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llvm-project/clang/lib/Sema/SemaInit.cpp

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//===--- SemaInit.cpp - Semantic Analysis for Initializers ----------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements semantic analysis for initializers.
//
//===----------------------------------------------------------------------===//
#include "clang/AST/ASTContext.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/ExprObjC.h"
#include "clang/AST/ExprOpenMP.h"
#include "clang/AST/TypeLoc.h"
#include "clang/Basic/CharInfo.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Sema/Designator.h"
#include "clang/Sema/Initialization.h"
#include "clang/Sema/Lookup.h"
#include "clang/Sema/SemaInternal.h"
#include "llvm/ADT/APInt.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
using namespace clang;
//===----------------------------------------------------------------------===//
// Sema Initialization Checking
//===----------------------------------------------------------------------===//
/// Check whether T is compatible with a wide character type (wchar_t,
/// char16_t or char32_t).
static bool IsWideCharCompatible(QualType T, ASTContext &Context) {
if (Context.typesAreCompatible(Context.getWideCharType(), T))
return true;
if (Context.getLangOpts().CPlusPlus || Context.getLangOpts().C11) {
return Context.typesAreCompatible(Context.Char16Ty, T) ||
Context.typesAreCompatible(Context.Char32Ty, T);
}
return false;
}
enum StringInitFailureKind {
SIF_None,
SIF_NarrowStringIntoWideChar,
SIF_WideStringIntoChar,
SIF_IncompatWideStringIntoWideChar,
SIF_UTF8StringIntoPlainChar,
SIF_PlainStringIntoUTF8Char,
SIF_Other
};
/// Check whether the array of type AT can be initialized by the Init
/// expression by means of string initialization. Returns SIF_None if so,
/// otherwise returns a StringInitFailureKind that describes why the
/// initialization would not work.
static StringInitFailureKind IsStringInit(Expr *Init, const ArrayType *AT,
ASTContext &Context) {
if (!isa<ConstantArrayType>(AT) && !isa<IncompleteArrayType>(AT))
return SIF_Other;
// See if this is a string literal or @encode.
Init = Init->IgnoreParens();
// Handle @encode, which is a narrow string.
if (isa<ObjCEncodeExpr>(Init) && AT->getElementType()->isCharType())
return SIF_None;
// Otherwise we can only handle string literals.
StringLiteral *SL = dyn_cast<StringLiteral>(Init);
if (!SL)
return SIF_Other;
const QualType ElemTy =
Context.getCanonicalType(AT->getElementType()).getUnqualifiedType();
switch (SL->getKind()) {
case StringLiteral::UTF8:
// char8_t array can be initialized with a UTF-8 string.
if (ElemTy->isChar8Type())
return SIF_None;
LLVM_FALLTHROUGH;
case StringLiteral::Ascii:
// char array can be initialized with a narrow string.
// Only allow char x[] = "foo"; not char x[] = L"foo";
if (ElemTy->isCharType())
return (SL->getKind() == StringLiteral::UTF8 &&
Context.getLangOpts().Char8)
? SIF_UTF8StringIntoPlainChar
: SIF_None;
if (ElemTy->isChar8Type())
return SIF_PlainStringIntoUTF8Char;
if (IsWideCharCompatible(ElemTy, Context))
return SIF_NarrowStringIntoWideChar;
return SIF_Other;
// C99 6.7.8p15 (with correction from DR343), or C11 6.7.9p15:
// "An array with element type compatible with a qualified or unqualified
// version of wchar_t, char16_t, or char32_t may be initialized by a wide
// string literal with the corresponding encoding prefix (L, u, or U,
// respectively), optionally enclosed in braces.
case StringLiteral::UTF16:
if (Context.typesAreCompatible(Context.Char16Ty, ElemTy))
return SIF_None;
if (ElemTy->isCharType() || ElemTy->isChar8Type())
return SIF_WideStringIntoChar;
if (IsWideCharCompatible(ElemTy, Context))
return SIF_IncompatWideStringIntoWideChar;
return SIF_Other;
case StringLiteral::UTF32:
if (Context.typesAreCompatible(Context.Char32Ty, ElemTy))
return SIF_None;
if (ElemTy->isCharType() || ElemTy->isChar8Type())
return SIF_WideStringIntoChar;
if (IsWideCharCompatible(ElemTy, Context))
return SIF_IncompatWideStringIntoWideChar;
return SIF_Other;
case StringLiteral::Wide:
if (Context.typesAreCompatible(Context.getWideCharType(), ElemTy))
return SIF_None;
if (ElemTy->isCharType() || ElemTy->isChar8Type())
return SIF_WideStringIntoChar;
if (IsWideCharCompatible(ElemTy, Context))
return SIF_IncompatWideStringIntoWideChar;
return SIF_Other;
}
llvm_unreachable("missed a StringLiteral kind?");
}
static StringInitFailureKind IsStringInit(Expr *init, QualType declType,
ASTContext &Context) {
const ArrayType *arrayType = Context.getAsArrayType(declType);
if (!arrayType)
return SIF_Other;
return IsStringInit(init, arrayType, Context);
}
bool Sema::IsStringInit(Expr *Init, const ArrayType *AT) {
return ::IsStringInit(Init, AT, Context) == SIF_None;
}
/// Update the type of a string literal, including any surrounding parentheses,
/// to match the type of the object which it is initializing.
static void updateStringLiteralType(Expr *E, QualType Ty) {
while (true) {
E->setType(Ty);
E->setValueKind(VK_RValue);
if (isa<StringLiteral>(E) || isa<ObjCEncodeExpr>(E)) {
break;
} else if (ParenExpr *PE = dyn_cast<ParenExpr>(E)) {
E = PE->getSubExpr();
} else if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
assert(UO->getOpcode() == UO_Extension);
E = UO->getSubExpr();
} else if (GenericSelectionExpr *GSE = dyn_cast<GenericSelectionExpr>(E)) {
E = GSE->getResultExpr();
} else if (ChooseExpr *CE = dyn_cast<ChooseExpr>(E)) {
E = CE->getChosenSubExpr();
} else {
llvm_unreachable("unexpected expr in string literal init");
}
}
}
/// Fix a compound literal initializing an array so it's correctly marked
/// as an rvalue.
static void updateGNUCompoundLiteralRValue(Expr *E) {
while (true) {
E->setValueKind(VK_RValue);
if (isa<CompoundLiteralExpr>(E)) {
break;
} else if (ParenExpr *PE = dyn_cast<ParenExpr>(E)) {
E = PE->getSubExpr();
} else if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
assert(UO->getOpcode() == UO_Extension);
E = UO->getSubExpr();
} else if (GenericSelectionExpr *GSE = dyn_cast<GenericSelectionExpr>(E)) {
E = GSE->getResultExpr();
} else if (ChooseExpr *CE = dyn_cast<ChooseExpr>(E)) {
E = CE->getChosenSubExpr();
} else {
llvm_unreachable("unexpected expr in array compound literal init");
}
}
}
static void CheckStringInit(Expr *Str, QualType &DeclT, const ArrayType *AT,
Sema &S) {
// Get the length of the string as parsed.
auto *ConstantArrayTy =
cast<ConstantArrayType>(Str->getType()->getAsArrayTypeUnsafe());
uint64_t StrLength = ConstantArrayTy->getSize().getZExtValue();
if (const IncompleteArrayType *IAT = dyn_cast<IncompleteArrayType>(AT)) {
// C99 6.7.8p14. We have an array of character type with unknown size
// being initialized to a string literal.
llvm::APInt ConstVal(32, StrLength);
// Return a new array type (C99 6.7.8p22).
DeclT = S.Context.getConstantArrayType(IAT->getElementType(),
ConstVal, nullptr,
ArrayType::Normal, 0);
updateStringLiteralType(Str, DeclT);
return;
}
const ConstantArrayType *CAT = cast<ConstantArrayType>(AT);
// We have an array of character type with known size. However,
// the size may be smaller or larger than the string we are initializing.
// FIXME: Avoid truncation for 64-bit length strings.
if (S.getLangOpts().CPlusPlus) {
if (StringLiteral *SL = dyn_cast<StringLiteral>(Str->IgnoreParens())) {
// For Pascal strings it's OK to strip off the terminating null character,
// so the example below is valid:
//
// unsigned char a[2] = "\pa";
if (SL->isPascal())
StrLength--;
}
// [dcl.init.string]p2
if (StrLength > CAT->getSize().getZExtValue())
S.Diag(Str->getBeginLoc(),
diag::err_initializer_string_for_char_array_too_long)
<< Str->getSourceRange();
} else {
// C99 6.7.8p14.
if (StrLength-1 > CAT->getSize().getZExtValue())
S.Diag(Str->getBeginLoc(),
diag::ext_initializer_string_for_char_array_too_long)
<< Str->getSourceRange();
}
// Set the type to the actual size that we are initializing. If we have
// something like:
// char x[1] = "foo";
// then this will set the string literal's type to char[1].
updateStringLiteralType(Str, DeclT);
}
//===----------------------------------------------------------------------===//
// Semantic checking for initializer lists.
//===----------------------------------------------------------------------===//
namespace {
/// Semantic checking for initializer lists.
///
/// The InitListChecker class contains a set of routines that each
/// handle the initialization of a certain kind of entity, e.g.,
/// arrays, vectors, struct/union types, scalars, etc. The
/// InitListChecker itself performs a recursive walk of the subobject
/// structure of the type to be initialized, while stepping through
/// the initializer list one element at a time. The IList and Index
/// parameters to each of the Check* routines contain the active
/// (syntactic) initializer list and the index into that initializer
/// list that represents the current initializer. Each routine is
/// responsible for moving that Index forward as it consumes elements.
///
/// Each Check* routine also has a StructuredList/StructuredIndex
/// arguments, which contains the current "structured" (semantic)
/// initializer list and the index into that initializer list where we
/// are copying initializers as we map them over to the semantic
/// list. Once we have completed our recursive walk of the subobject
/// structure, we will have constructed a full semantic initializer
/// list.
///
/// C99 designators cause changes in the initializer list traversal,
/// because they make the initialization "jump" into a specific
/// subobject and then continue the initialization from that
/// point. CheckDesignatedInitializer() recursively steps into the
/// designated subobject and manages backing out the recursion to
/// initialize the subobjects after the one designated.
///
/// If an initializer list contains any designators, we build a placeholder
/// structured list even in 'verify only' mode, so that we can track which
/// elements need 'empty' initializtion.
class InitListChecker {
Sema &SemaRef;
bool hadError = false;
bool VerifyOnly; // No diagnostics.
bool TreatUnavailableAsInvalid; // Used only in VerifyOnly mode.
bool InOverloadResolution;
InitListExpr *FullyStructuredList = nullptr;
NoInitExpr *DummyExpr = nullptr;
NoInitExpr *getDummyInit() {
if (!DummyExpr)
DummyExpr = new (SemaRef.Context) NoInitExpr(SemaRef.Context.VoidTy);
return DummyExpr;
}
void CheckImplicitInitList(const InitializedEntity &Entity,
InitListExpr *ParentIList, QualType T,
unsigned &Index, InitListExpr *StructuredList,
unsigned &StructuredIndex);
void CheckExplicitInitList(const InitializedEntity &Entity,
InitListExpr *IList, QualType &T,
InitListExpr *StructuredList,
bool TopLevelObject = false);
void CheckListElementTypes(const InitializedEntity &Entity,
InitListExpr *IList, QualType &DeclType,
bool SubobjectIsDesignatorContext,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex,
bool TopLevelObject = false);
void CheckSubElementType(const InitializedEntity &Entity,
InitListExpr *IList, QualType ElemType,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex);
void CheckComplexType(const InitializedEntity &Entity,
InitListExpr *IList, QualType DeclType,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex);
void CheckScalarType(const InitializedEntity &Entity,
InitListExpr *IList, QualType DeclType,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex);
void CheckReferenceType(const InitializedEntity &Entity,
InitListExpr *IList, QualType DeclType,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex);
void CheckVectorType(const InitializedEntity &Entity,
InitListExpr *IList, QualType DeclType, unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex);
void CheckStructUnionTypes(const InitializedEntity &Entity,
InitListExpr *IList, QualType DeclType,
CXXRecordDecl::base_class_range Bases,
RecordDecl::field_iterator Field,
bool SubobjectIsDesignatorContext, unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex,
bool TopLevelObject = false);
void CheckArrayType(const InitializedEntity &Entity,
InitListExpr *IList, QualType &DeclType,
llvm::APSInt elementIndex,
bool SubobjectIsDesignatorContext, unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex);
bool CheckDesignatedInitializer(const InitializedEntity &Entity,
InitListExpr *IList, DesignatedInitExpr *DIE,
unsigned DesigIdx,
QualType &CurrentObjectType,
RecordDecl::field_iterator *NextField,
llvm::APSInt *NextElementIndex,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex,
bool FinishSubobjectInit,
bool TopLevelObject);
InitListExpr *getStructuredSubobjectInit(InitListExpr *IList, unsigned Index,
QualType CurrentObjectType,
InitListExpr *StructuredList,
unsigned StructuredIndex,
SourceRange InitRange,
bool IsFullyOverwritten = false);
void UpdateStructuredListElement(InitListExpr *StructuredList,
unsigned &StructuredIndex,
Expr *expr);
InitListExpr *createInitListExpr(QualType CurrentObjectType,
SourceRange InitRange,
unsigned ExpectedNumInits);
int numArrayElements(QualType DeclType);
int numStructUnionElements(QualType DeclType);
ExprResult PerformEmptyInit(SourceLocation Loc,
const InitializedEntity &Entity);
/// Diagnose that OldInit (or part thereof) has been overridden by NewInit.
void diagnoseInitOverride(Expr *OldInit, SourceRange NewInitRange,
bool FullyOverwritten = true) {
// Overriding an initializer via a designator is valid with C99 designated
// initializers, but ill-formed with C++20 designated initializers.
unsigned DiagID = SemaRef.getLangOpts().CPlusPlus
? diag::ext_initializer_overrides
: diag::warn_initializer_overrides;
if (InOverloadResolution && SemaRef.getLangOpts().CPlusPlus) {
// In overload resolution, we have to strictly enforce the rules, and so
// don't allow any overriding of prior initializers. This matters for a
// case such as:
//
// union U { int a, b; };
// struct S { int a, b; };
// void f(U), f(S);
//
// Here, f({.a = 1, .b = 2}) is required to call the struct overload. For
// consistency, we disallow all overriding of prior initializers in
// overload resolution, not only overriding of union members.
hadError = true;
} else if (OldInit->getType().isDestructedType() && !FullyOverwritten) {
// If we'll be keeping around the old initializer but overwriting part of
// the object it initialized, and that object is not trivially
// destructible, this can leak. Don't allow that, not even as an
// extension.
//
// FIXME: It might be reasonable to allow this in cases where the part of
// the initializer that we're overriding has trivial destruction.
DiagID = diag::err_initializer_overrides_destructed;
} else if (!OldInit->getSourceRange().isValid()) {
// We need to check on source range validity because the previous
// initializer does not have to be an explicit initializer. e.g.,
//
// struct P { int a, b; };
// struct PP { struct P p } l = { { .a = 2 }, .p.b = 3 };
//
// There is an overwrite taking place because the first braced initializer
// list "{ .a = 2 }" already provides value for .p.b (which is zero).
//
// Such overwrites are harmless, so we don't diagnose them. (Note that in
// C++, this cannot be reached unless we've already seen and diagnosed a
// different conformance issue, such as a mixture of designated and
// non-designated initializers or a multi-level designator.)
return;
}
if (!VerifyOnly) {
SemaRef.Diag(NewInitRange.getBegin(), DiagID)
<< NewInitRange << FullyOverwritten << OldInit->getType();
SemaRef.Diag(OldInit->getBeginLoc(), diag::note_previous_initializer)
<< (OldInit->HasSideEffects(SemaRef.Context) && FullyOverwritten)
<< OldInit->getSourceRange();
}
}
// Explanation on the "FillWithNoInit" mode:
//
// Assume we have the following definitions (Case#1):
// struct P { char x[6][6]; } xp = { .x[1] = "bar" };
// struct PP { struct P lp; } l = { .lp = xp, .lp.x[1][2] = 'f' };
//
// l.lp.x[1][0..1] should not be filled with implicit initializers because the
// "base" initializer "xp" will provide values for them; l.lp.x[1] will be "baf".
//
// But if we have (Case#2):
// struct PP l = { .lp = xp, .lp.x[1] = { [2] = 'f' } };
//
// l.lp.x[1][0..1] are implicitly initialized and do not use values from the
// "base" initializer; l.lp.x[1] will be "\0\0f\0\0\0".
//
// To distinguish Case#1 from Case#2, and also to avoid leaving many "holes"
// in the InitListExpr, the "holes" in Case#1 are filled not with empty
// initializers but with special "NoInitExpr" place holders, which tells the
// CodeGen not to generate any initializers for these parts.
void FillInEmptyInitForBase(unsigned Init, const CXXBaseSpecifier &Base,
const InitializedEntity &ParentEntity,
InitListExpr *ILE, bool &RequiresSecondPass,
bool FillWithNoInit);
void FillInEmptyInitForField(unsigned Init, FieldDecl *Field,
const InitializedEntity &ParentEntity,
InitListExpr *ILE, bool &RequiresSecondPass,
bool FillWithNoInit = false);
void FillInEmptyInitializations(const InitializedEntity &Entity,
InitListExpr *ILE, bool &RequiresSecondPass,
InitListExpr *OuterILE, unsigned OuterIndex,
bool FillWithNoInit = false);
bool CheckFlexibleArrayInit(const InitializedEntity &Entity,
Expr *InitExpr, FieldDecl *Field,
bool TopLevelObject);
void CheckEmptyInitializable(const InitializedEntity &Entity,
SourceLocation Loc);
public:
InitListChecker(Sema &S, const InitializedEntity &Entity, InitListExpr *IL,
QualType &T, bool VerifyOnly, bool TreatUnavailableAsInvalid,
bool InOverloadResolution = false);
bool HadError() { return hadError; }
// Retrieves the fully-structured initializer list used for
// semantic analysis and code generation.
InitListExpr *getFullyStructuredList() const { return FullyStructuredList; }
};
} // end anonymous namespace
ExprResult InitListChecker::PerformEmptyInit(SourceLocation Loc,
const InitializedEntity &Entity) {
InitializationKind Kind = InitializationKind::CreateValue(Loc, Loc, Loc,
true);
MultiExprArg SubInit;
Expr *InitExpr;
InitListExpr DummyInitList(SemaRef.Context, Loc, None, Loc);
// C++ [dcl.init.aggr]p7:
// If there are fewer initializer-clauses in the list than there are
// members in the aggregate, then each member not explicitly initialized
// ...
bool EmptyInitList = SemaRef.getLangOpts().CPlusPlus11 &&
Entity.getType()->getBaseElementTypeUnsafe()->isRecordType();
if (EmptyInitList) {
// C++1y / DR1070:
// shall be initialized [...] from an empty initializer list.
//
// We apply the resolution of this DR to C++11 but not C++98, since C++98
// does not have useful semantics for initialization from an init list.
// We treat this as copy-initialization, because aggregate initialization
// always performs copy-initialization on its elements.
//
// Only do this if we're initializing a class type, to avoid filling in
// the initializer list where possible.
InitExpr = VerifyOnly ? &DummyInitList : new (SemaRef.Context)
InitListExpr(SemaRef.Context, Loc, None, Loc);
InitExpr->setType(SemaRef.Context.VoidTy);
SubInit = InitExpr;
Kind = InitializationKind::CreateCopy(Loc, Loc);
} else {
// C++03:
// shall be value-initialized.
}
InitializationSequence InitSeq(SemaRef, Entity, Kind, SubInit);
// libstdc++4.6 marks the vector default constructor as explicit in
// _GLIBCXX_DEBUG mode, so recover using the C++03 logic in that case.
// stlport does so too. Look for std::__debug for libstdc++, and for
// std:: for stlport. This is effectively a compiler-side implementation of
// LWG2193.
if (!InitSeq && EmptyInitList && InitSeq.getFailureKind() ==
InitializationSequence::FK_ExplicitConstructor) {
OverloadCandidateSet::iterator Best;
OverloadingResult O =
InitSeq.getFailedCandidateSet()
.BestViableFunction(SemaRef, Kind.getLocation(), Best);
(void)O;
assert(O == OR_Success && "Inconsistent overload resolution");
CXXConstructorDecl *CtorDecl = cast<CXXConstructorDecl>(Best->Function);
CXXRecordDecl *R = CtorDecl->getParent();
if (CtorDecl->getMinRequiredArguments() == 0 &&
CtorDecl->isExplicit() && R->getDeclName() &&
SemaRef.SourceMgr.isInSystemHeader(CtorDecl->getLocation())) {
bool IsInStd = false;
for (NamespaceDecl *ND = dyn_cast<NamespaceDecl>(R->getDeclContext());
ND && !IsInStd; ND = dyn_cast<NamespaceDecl>(ND->getParent())) {
if (SemaRef.getStdNamespace()->InEnclosingNamespaceSetOf(ND))
IsInStd = true;
}
if (IsInStd && llvm::StringSwitch<bool>(R->getName())
.Cases("basic_string", "deque", "forward_list", true)
.Cases("list", "map", "multimap", "multiset", true)
.Cases("priority_queue", "queue", "set", "stack", true)
.Cases("unordered_map", "unordered_set", "vector", true)
.Default(false)) {
InitSeq.InitializeFrom(
SemaRef, Entity,
InitializationKind::CreateValue(Loc, Loc, Loc, true),
MultiExprArg(), /*TopLevelOfInitList=*/false,
TreatUnavailableAsInvalid);
// Emit a warning for this. System header warnings aren't shown
// by default, but people working on system headers should see it.
if (!VerifyOnly) {
SemaRef.Diag(CtorDecl->getLocation(),
diag::warn_invalid_initializer_from_system_header);
if (Entity.getKind() == InitializedEntity::EK_Member)
SemaRef.Diag(Entity.getDecl()->getLocation(),
diag::note_used_in_initialization_here);
else if (Entity.getKind() == InitializedEntity::EK_ArrayElement)
SemaRef.Diag(Loc, diag::note_used_in_initialization_here);
}
}
}
}
if (!InitSeq) {
if (!VerifyOnly) {
InitSeq.Diagnose(SemaRef, Entity, Kind, SubInit);
if (Entity.getKind() == InitializedEntity::EK_Member)
SemaRef.Diag(Entity.getDecl()->getLocation(),
diag::note_in_omitted_aggregate_initializer)
<< /*field*/1 << Entity.getDecl();
else if (Entity.getKind() == InitializedEntity::EK_ArrayElement) {
bool IsTrailingArrayNewMember =
Entity.getParent() &&
Entity.getParent()->isVariableLengthArrayNew();
SemaRef.Diag(Loc, diag::note_in_omitted_aggregate_initializer)
<< (IsTrailingArrayNewMember ? 2 : /*array element*/0)
<< Entity.getElementIndex();
}
}
hadError = true;
return ExprError();
}
return VerifyOnly ? ExprResult()
: InitSeq.Perform(SemaRef, Entity, Kind, SubInit);
}
void InitListChecker::CheckEmptyInitializable(const InitializedEntity &Entity,
SourceLocation Loc) {
// If we're building a fully-structured list, we'll check this at the end
// once we know which elements are actually initialized. Otherwise, we know
// that there are no designators so we can just check now.
if (FullyStructuredList)
return;
PerformEmptyInit(Loc, Entity);
}
void InitListChecker::FillInEmptyInitForBase(
unsigned Init, const CXXBaseSpecifier &Base,
const InitializedEntity &ParentEntity, InitListExpr *ILE,
bool &RequiresSecondPass, bool FillWithNoInit) {
InitializedEntity BaseEntity = InitializedEntity::InitializeBase(
SemaRef.Context, &Base, false, &ParentEntity);
if (Init >= ILE->getNumInits() || !ILE->getInit(Init)) {
ExprResult BaseInit = FillWithNoInit
? new (SemaRef.Context) NoInitExpr(Base.getType())
: PerformEmptyInit(ILE->getEndLoc(), BaseEntity);
if (BaseInit.isInvalid()) {
hadError = true;
return;
}
if (!VerifyOnly) {
assert(Init < ILE->getNumInits() && "should have been expanded");
ILE->setInit(Init, BaseInit.getAs<Expr>());
}
} else if (InitListExpr *InnerILE =
dyn_cast<InitListExpr>(ILE->getInit(Init))) {
FillInEmptyInitializations(BaseEntity, InnerILE, RequiresSecondPass,
ILE, Init, FillWithNoInit);
} else if (DesignatedInitUpdateExpr *InnerDIUE =
dyn_cast<DesignatedInitUpdateExpr>(ILE->getInit(Init))) {
FillInEmptyInitializations(BaseEntity, InnerDIUE->getUpdater(),
RequiresSecondPass, ILE, Init,
/*FillWithNoInit =*/true);
}
}
void InitListChecker::FillInEmptyInitForField(unsigned Init, FieldDecl *Field,
const InitializedEntity &ParentEntity,
InitListExpr *ILE,
bool &RequiresSecondPass,
bool FillWithNoInit) {
SourceLocation Loc = ILE->getEndLoc();
unsigned NumInits = ILE->getNumInits();
InitializedEntity MemberEntity
= InitializedEntity::InitializeMember(Field, &ParentEntity);
if (Init >= NumInits || !ILE->getInit(Init)) {
if (const RecordType *RType = ILE->getType()->getAs<RecordType>())
if (!RType->getDecl()->isUnion())
assert((Init < NumInits || VerifyOnly) &&
"This ILE should have been expanded");
if (FillWithNoInit) {
assert(!VerifyOnly && "should not fill with no-init in verify-only mode");
Expr *Filler = new (SemaRef.Context) NoInitExpr(Field->getType());
if (Init < NumInits)
ILE->setInit(Init, Filler);
else
ILE->updateInit(SemaRef.Context, Init, Filler);
return;
}
// C++1y [dcl.init.aggr]p7:
// If there are fewer initializer-clauses in the list than there are
// members in the aggregate, then each member not explicitly initialized
// shall be initialized from its brace-or-equal-initializer [...]
if (Field->hasInClassInitializer()) {
if (VerifyOnly)
return;
ExprResult DIE = SemaRef.BuildCXXDefaultInitExpr(Loc, Field);
if (DIE.isInvalid()) {
hadError = true;
return;
}
SemaRef.checkInitializerLifetime(MemberEntity, DIE.get());
if (Init < NumInits)
ILE->setInit(Init, DIE.get());
else {
ILE->updateInit(SemaRef.Context, Init, DIE.get());
RequiresSecondPass = true;
}
return;
}
if (Field->getType()->isReferenceType()) {
if (!VerifyOnly) {
// C++ [dcl.init.aggr]p9:
// If an incomplete or empty initializer-list leaves a
// member of reference type uninitialized, the program is
// ill-formed.
SemaRef.Diag(Loc, diag::err_init_reference_member_uninitialized)
<< Field->getType()
<< ILE->getSyntacticForm()->getSourceRange();
SemaRef.Diag(Field->getLocation(),
diag::note_uninit_reference_member);
}
hadError = true;
return;
}
ExprResult MemberInit = PerformEmptyInit(Loc, MemberEntity);
if (MemberInit.isInvalid()) {
hadError = true;
return;
}
if (hadError || VerifyOnly) {
// Do nothing
} else if (Init < NumInits) {
ILE->setInit(Init, MemberInit.getAs<Expr>());
} else if (!isa<ImplicitValueInitExpr>(MemberInit.get())) {
// Empty initialization requires a constructor call, so
// extend the initializer list to include the constructor
// call and make a note that we'll need to take another pass
// through the initializer list.
ILE->updateInit(SemaRef.Context, Init, MemberInit.getAs<Expr>());
RequiresSecondPass = true;
}
} else if (InitListExpr *InnerILE
= dyn_cast<InitListExpr>(ILE->getInit(Init))) {
FillInEmptyInitializations(MemberEntity, InnerILE,
RequiresSecondPass, ILE, Init, FillWithNoInit);
} else if (DesignatedInitUpdateExpr *InnerDIUE =
dyn_cast<DesignatedInitUpdateExpr>(ILE->getInit(Init))) {
FillInEmptyInitializations(MemberEntity, InnerDIUE->getUpdater(),
RequiresSecondPass, ILE, Init,
/*FillWithNoInit =*/true);
}
}
/// Recursively replaces NULL values within the given initializer list
/// with expressions that perform value-initialization of the
/// appropriate type, and finish off the InitListExpr formation.
void
InitListChecker::FillInEmptyInitializations(const InitializedEntity &Entity,
InitListExpr *ILE,
bool &RequiresSecondPass,
InitListExpr *OuterILE,
unsigned OuterIndex,
bool FillWithNoInit) {
assert((ILE->getType() != SemaRef.Context.VoidTy) &&
"Should not have void type");
// We don't need to do any checks when just filling NoInitExprs; that can't
// fail.
if (FillWithNoInit && VerifyOnly)
return;
// If this is a nested initializer list, we might have changed its contents
// (and therefore some of its properties, such as instantiation-dependence)
// while filling it in. Inform the outer initializer list so that its state
// can be updated to match.
// FIXME: We should fully build the inner initializers before constructing
// the outer InitListExpr instead of mutating AST nodes after they have
// been used as subexpressions of other nodes.
struct UpdateOuterILEWithUpdatedInit {
InitListExpr *Outer;
unsigned OuterIndex;
~UpdateOuterILEWithUpdatedInit() {
if (Outer)
Outer->setInit(OuterIndex, Outer->getInit(OuterIndex));
}
} UpdateOuterRAII = {OuterILE, OuterIndex};
// A transparent ILE is not performing aggregate initialization and should
// not be filled in.
if (ILE->isTransparent())
return;
if (const RecordType *RType = ILE->getType()->getAs<RecordType>()) {
const RecordDecl *RDecl = RType->getDecl();
if (RDecl->isUnion() && ILE->getInitializedFieldInUnion())
FillInEmptyInitForField(0, ILE->getInitializedFieldInUnion(),
Entity, ILE, RequiresSecondPass, FillWithNoInit);
else if (RDecl->isUnion() && isa<CXXRecordDecl>(RDecl) &&
cast<CXXRecordDecl>(RDecl)->hasInClassInitializer()) {
for (auto *Field : RDecl->fields()) {
if (Field->hasInClassInitializer()) {
FillInEmptyInitForField(0, Field, Entity, ILE, RequiresSecondPass,
FillWithNoInit);
break;
}
}
} else {
// The fields beyond ILE->getNumInits() are default initialized, so in
// order to leave them uninitialized, the ILE is expanded and the extra
// fields are then filled with NoInitExpr.
unsigned NumElems = numStructUnionElements(ILE->getType());
if (RDecl->hasFlexibleArrayMember())
++NumElems;
if (!VerifyOnly && ILE->getNumInits() < NumElems)
ILE->resizeInits(SemaRef.Context, NumElems);
unsigned Init = 0;
if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RDecl)) {
for (auto &Base : CXXRD->bases()) {
if (hadError)
return;
FillInEmptyInitForBase(Init, Base, Entity, ILE, RequiresSecondPass,
FillWithNoInit);
++Init;
}
}
for (auto *Field : RDecl->fields()) {
if (Field->isUnnamedBitfield())
continue;
if (hadError)
return;
FillInEmptyInitForField(Init, Field, Entity, ILE, RequiresSecondPass,
FillWithNoInit);
if (hadError)
return;
++Init;
// Only look at the first initialization of a union.
if (RDecl->isUnion())
break;
}
}
return;
}
QualType ElementType;
InitializedEntity ElementEntity = Entity;
unsigned NumInits = ILE->getNumInits();
unsigned NumElements = NumInits;
if (const ArrayType *AType = SemaRef.Context.getAsArrayType(ILE->getType())) {
ElementType = AType->getElementType();
if (const auto *CAType = dyn_cast<ConstantArrayType>(AType))
NumElements = CAType->getSize().getZExtValue();
// For an array new with an unknown bound, ask for one additional element
// in order to populate the array filler.
if (Entity.isVariableLengthArrayNew())
++NumElements;
ElementEntity = InitializedEntity::InitializeElement(SemaRef.Context,
0, Entity);
} else if (const VectorType *VType = ILE->getType()->getAs<VectorType>()) {
ElementType = VType->getElementType();
NumElements = VType->getNumElements();
ElementEntity = InitializedEntity::InitializeElement(SemaRef.Context,
0, Entity);
} else
ElementType = ILE->getType();
bool SkipEmptyInitChecks = false;
for (unsigned Init = 0; Init != NumElements; ++Init) {
if (hadError)
return;
if (ElementEntity.getKind() == InitializedEntity::EK_ArrayElement ||
ElementEntity.getKind() == InitializedEntity::EK_VectorElement)
ElementEntity.setElementIndex(Init);
if (Init >= NumInits && (ILE->hasArrayFiller() || SkipEmptyInitChecks))
return;
Expr *InitExpr = (Init < NumInits ? ILE->getInit(Init) : nullptr);
if (!InitExpr && Init < NumInits && ILE->hasArrayFiller())
ILE->setInit(Init, ILE->getArrayFiller());
else if (!InitExpr && !ILE->hasArrayFiller()) {
// In VerifyOnly mode, there's no point performing empty initialization
// more than once.
if (SkipEmptyInitChecks)
continue;
Expr *Filler = nullptr;
if (FillWithNoInit)
Filler = new (SemaRef.Context) NoInitExpr(ElementType);
else {
ExprResult ElementInit =
PerformEmptyInit(ILE->getEndLoc(), ElementEntity);
if (ElementInit.isInvalid()) {
hadError = true;
return;
}
Filler = ElementInit.getAs<Expr>();
}
if (hadError) {
// Do nothing
} else if (VerifyOnly) {
SkipEmptyInitChecks = true;
} else if (Init < NumInits) {
// For arrays, just set the expression used for value-initialization
// of the "holes" in the array.
if (ElementEntity.getKind() == InitializedEntity::EK_ArrayElement)
ILE->setArrayFiller(Filler);
else
ILE->setInit(Init, Filler);
} else {
// For arrays, just set the expression used for value-initialization
// of the rest of elements and exit.
if (ElementEntity.getKind() == InitializedEntity::EK_ArrayElement) {
ILE->setArrayFiller(Filler);
return;
}
if (!isa<ImplicitValueInitExpr>(Filler) && !isa<NoInitExpr>(Filler)) {
// Empty initialization requires a constructor call, so
// extend the initializer list to include the constructor
// call and make a note that we'll need to take another pass
// through the initializer list.
ILE->updateInit(SemaRef.Context, Init, Filler);
RequiresSecondPass = true;
}
}
} else if (InitListExpr *InnerILE
= dyn_cast_or_null<InitListExpr>(InitExpr)) {
FillInEmptyInitializations(ElementEntity, InnerILE, RequiresSecondPass,
ILE, Init, FillWithNoInit);
} else if (DesignatedInitUpdateExpr *InnerDIUE =
dyn_cast_or_null<DesignatedInitUpdateExpr>(InitExpr)) {
FillInEmptyInitializations(ElementEntity, InnerDIUE->getUpdater(),
RequiresSecondPass, ILE, Init,
/*FillWithNoInit =*/true);
}
}
}
static bool hasAnyDesignatedInits(const InitListExpr *IL) {
for (const Stmt *Init : *IL)
if (Init && isa<DesignatedInitExpr>(Init))
return true;
return false;
}
InitListChecker::InitListChecker(Sema &S, const InitializedEntity &Entity,
InitListExpr *IL, QualType &T, bool VerifyOnly,
bool TreatUnavailableAsInvalid,
bool InOverloadResolution)
: SemaRef(S), VerifyOnly(VerifyOnly),
TreatUnavailableAsInvalid(TreatUnavailableAsInvalid),
InOverloadResolution(InOverloadResolution) {
if (!VerifyOnly || hasAnyDesignatedInits(IL)) {
FullyStructuredList =
createInitListExpr(T, IL->getSourceRange(), IL->getNumInits());
// FIXME: Check that IL isn't already the semantic form of some other
// InitListExpr. If it is, we'd create a broken AST.
if (!VerifyOnly)
FullyStructuredList->setSyntacticForm(IL);
}
CheckExplicitInitList(Entity, IL, T, FullyStructuredList,
/*TopLevelObject=*/true);
if (!hadError && FullyStructuredList) {
bool RequiresSecondPass = false;
FillInEmptyInitializations(Entity, FullyStructuredList, RequiresSecondPass,
/*OuterILE=*/nullptr, /*OuterIndex=*/0);
if (RequiresSecondPass && !hadError)
FillInEmptyInitializations(Entity, FullyStructuredList,
RequiresSecondPass, nullptr, 0);
}
if (hadError && FullyStructuredList)
FullyStructuredList->markError();
}
int InitListChecker::numArrayElements(QualType DeclType) {
// FIXME: use a proper constant
int maxElements = 0x7FFFFFFF;
if (const ConstantArrayType *CAT =
SemaRef.Context.getAsConstantArrayType(DeclType)) {
maxElements = static_cast<int>(CAT->getSize().getZExtValue());
}
return maxElements;
}
int InitListChecker::numStructUnionElements(QualType DeclType) {
RecordDecl *structDecl = DeclType->castAs<RecordType>()->getDecl();
int InitializableMembers = 0;
if (auto *CXXRD = dyn_cast<CXXRecordDecl>(structDecl))
InitializableMembers += CXXRD->getNumBases();
for (const auto *Field : structDecl->fields())
if (!Field->isUnnamedBitfield())
++InitializableMembers;
if (structDecl->isUnion())
return std::min(InitializableMembers, 1);
return InitializableMembers - structDecl->hasFlexibleArrayMember();
}
/// Determine whether Entity is an entity for which it is idiomatic to elide
/// the braces in aggregate initialization.
static bool isIdiomaticBraceElisionEntity(const InitializedEntity &Entity) {
// Recursive initialization of the one and only field within an aggregate
// class is considered idiomatic. This case arises in particular for
// initialization of std::array, where the C++ standard suggests the idiom of
//
// std::array<T, N> arr = {1, 2, 3};
//
// (where std::array is an aggregate struct containing a single array field.
// FIXME: Should aggregate initialization of a struct with a single
// base class and no members also suppress the warning?
if (Entity.getKind() != InitializedEntity::EK_Member || !Entity.getParent())
return false;
auto *ParentRD =
Entity.getParent()->getType()->castAs<RecordType>()->getDecl();
if (CXXRecordDecl *CXXRD = dyn_cast<CXXRecordDecl>(ParentRD))
if (CXXRD->getNumBases())
return false;
auto FieldIt = ParentRD->field_begin();
assert(FieldIt != ParentRD->field_end() &&
"no fields but have initializer for member?");
return ++FieldIt == ParentRD->field_end();
}
/// Check whether the range of the initializer \p ParentIList from element
/// \p Index onwards can be used to initialize an object of type \p T. Update
/// \p Index to indicate how many elements of the list were consumed.
///
/// This also fills in \p StructuredList, from element \p StructuredIndex
/// onwards, with the fully-braced, desugared form of the initialization.
void InitListChecker::CheckImplicitInitList(const InitializedEntity &Entity,
InitListExpr *ParentIList,
QualType T, unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex) {
int maxElements = 0;
if (T->isArrayType())
maxElements = numArrayElements(T);
else if (T->isRecordType())
maxElements = numStructUnionElements(T);
else if (T->isVectorType())
maxElements = T->castAs<VectorType>()->getNumElements();
else
llvm_unreachable("CheckImplicitInitList(): Illegal type");
if (maxElements == 0) {
if (!VerifyOnly)
SemaRef.Diag(ParentIList->getInit(Index)->getBeginLoc(),
diag::err_implicit_empty_initializer);
++Index;
hadError = true;
return;
}
// Build a structured initializer list corresponding to this subobject.
InitListExpr *StructuredSubobjectInitList = getStructuredSubobjectInit(
ParentIList, Index, T, StructuredList, StructuredIndex,
SourceRange(ParentIList->getInit(Index)->getBeginLoc(),
ParentIList->getSourceRange().getEnd()));
unsigned StructuredSubobjectInitIndex = 0;
// Check the element types and build the structural subobject.
unsigned StartIndex = Index;
CheckListElementTypes(Entity, ParentIList, T,
/*SubobjectIsDesignatorContext=*/false, Index,
StructuredSubobjectInitList,
StructuredSubobjectInitIndex);
if (StructuredSubobjectInitList) {
StructuredSubobjectInitList->setType(T);
unsigned EndIndex = (Index == StartIndex? StartIndex : Index - 1);
// Update the structured sub-object initializer so that it's ending
// range corresponds with the end of the last initializer it used.
if (EndIndex < ParentIList->getNumInits() &&
ParentIList->getInit(EndIndex)) {
SourceLocation EndLoc
= ParentIList->getInit(EndIndex)->getSourceRange().getEnd();
StructuredSubobjectInitList->setRBraceLoc(EndLoc);
}
// Complain about missing braces.
if (!VerifyOnly && (T->isArrayType() || T->isRecordType()) &&
!ParentIList->isIdiomaticZeroInitializer(SemaRef.getLangOpts()) &&
!isIdiomaticBraceElisionEntity(Entity)) {
SemaRef.Diag(StructuredSubobjectInitList->getBeginLoc(),
diag::warn_missing_braces)
<< StructuredSubobjectInitList->getSourceRange()
<< FixItHint::CreateInsertion(
StructuredSubobjectInitList->getBeginLoc(), "{")
<< FixItHint::CreateInsertion(
SemaRef.getLocForEndOfToken(
StructuredSubobjectInitList->getEndLoc()),
"}");
}
// Warn if this type won't be an aggregate in future versions of C++.
auto *CXXRD = T->getAsCXXRecordDecl();
if (!VerifyOnly && CXXRD && CXXRD->hasUserDeclaredConstructor()) {
SemaRef.Diag(StructuredSubobjectInitList->getBeginLoc(),
diag::warn_cxx20_compat_aggregate_init_with_ctors)
<< StructuredSubobjectInitList->getSourceRange() << T;
}
}
}
/// Warn that \p Entity was of scalar type and was initialized by a
/// single-element braced initializer list.
static void warnBracedScalarInit(Sema &S, const InitializedEntity &Entity,
SourceRange Braces) {
// Don't warn during template instantiation. If the initialization was
// non-dependent, we warned during the initial parse; otherwise, the
// type might not be scalar in some uses of the template.
if (S.inTemplateInstantiation())
return;
unsigned DiagID = 0;
switch (Entity.getKind()) {
case InitializedEntity::EK_VectorElement:
case InitializedEntity::EK_ComplexElement:
case InitializedEntity::EK_ArrayElement:
case InitializedEntity::EK_Parameter:
case InitializedEntity::EK_Parameter_CF_Audited:
case InitializedEntity::EK_TemplateParameter:
case InitializedEntity::EK_Result:
// Extra braces here are suspicious.
DiagID = diag::warn_braces_around_init;
break;
case InitializedEntity::EK_Member:
// Warn on aggregate initialization but not on ctor init list or
// default member initializer.
if (Entity.getParent())
DiagID = diag::warn_braces_around_init;
break;
case InitializedEntity::EK_Variable:
case InitializedEntity::EK_LambdaCapture:
// No warning, might be direct-list-initialization.
// FIXME: Should we warn for copy-list-initialization in these cases?
break;
case InitializedEntity::EK_New:
case InitializedEntity::EK_Temporary:
case InitializedEntity::EK_CompoundLiteralInit:
// No warning, braces are part of the syntax of the underlying construct.
break;
case InitializedEntity::EK_RelatedResult:
// No warning, we already warned when initializing the result.
break;
case InitializedEntity::EK_Exception:
case InitializedEntity::EK_Base:
case InitializedEntity::EK_Delegating:
case InitializedEntity::EK_BlockElement:
case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
case InitializedEntity::EK_Binding:
case InitializedEntity::EK_StmtExprResult:
llvm_unreachable("unexpected braced scalar init");
}
if (DiagID) {
S.Diag(Braces.getBegin(), DiagID)
<< Entity.getType()->isSizelessBuiltinType() << Braces
<< FixItHint::CreateRemoval(Braces.getBegin())
<< FixItHint::CreateRemoval(Braces.getEnd());
}
}
/// Check whether the initializer \p IList (that was written with explicit
/// braces) can be used to initialize an object of type \p T.
///
/// This also fills in \p StructuredList with the fully-braced, desugared
/// form of the initialization.
void InitListChecker::CheckExplicitInitList(const InitializedEntity &Entity,
InitListExpr *IList, QualType &T,
InitListExpr *StructuredList,
bool TopLevelObject) {
unsigned Index = 0, StructuredIndex = 0;
CheckListElementTypes(Entity, IList, T, /*SubobjectIsDesignatorContext=*/true,
Index, StructuredList, StructuredIndex, TopLevelObject);
if (StructuredList) {
QualType ExprTy = T;
if (!ExprTy->isArrayType())
ExprTy = ExprTy.getNonLValueExprType(SemaRef.Context);
if (!VerifyOnly)
IList->setType(ExprTy);
StructuredList->setType(ExprTy);
}
if (hadError)
return;
// Don't complain for incomplete types, since we'll get an error elsewhere.
if (Index < IList->getNumInits() && !T->isIncompleteType()) {
// We have leftover initializers
bool ExtraInitsIsError = SemaRef.getLangOpts().CPlusPlus ||
(SemaRef.getLangOpts().OpenCL && T->isVectorType());
hadError = ExtraInitsIsError;
if (VerifyOnly) {
return;
} else if (StructuredIndex == 1 &&
IsStringInit(StructuredList->getInit(0), T, SemaRef.Context) ==
SIF_None) {
unsigned DK =
ExtraInitsIsError
? diag::err_excess_initializers_in_char_array_initializer
: diag::ext_excess_initializers_in_char_array_initializer;
SemaRef.Diag(IList->getInit(Index)->getBeginLoc(), DK)
<< IList->getInit(Index)->getSourceRange();
} else if (T->isSizelessBuiltinType()) {
unsigned DK = ExtraInitsIsError
? diag::err_excess_initializers_for_sizeless_type
: diag::ext_excess_initializers_for_sizeless_type;
SemaRef.Diag(IList->getInit(Index)->getBeginLoc(), DK)
<< T << IList->getInit(Index)->getSourceRange();
} else {
int initKind = T->isArrayType() ? 0 :
T->isVectorType() ? 1 :
T->isScalarType() ? 2 :
T->isUnionType() ? 3 :
4;
unsigned DK = ExtraInitsIsError ? diag::err_excess_initializers
: diag::ext_excess_initializers;
SemaRef.Diag(IList->getInit(Index)->getBeginLoc(), DK)
<< initKind << IList->getInit(Index)->getSourceRange();
}
}
if (!VerifyOnly) {
if (T->isScalarType() && IList->getNumInits() == 1 &&
!isa<InitListExpr>(IList->getInit(0)))
warnBracedScalarInit(SemaRef, Entity, IList->getSourceRange());
// Warn if this is a class type that won't be an aggregate in future
// versions of C++.
auto *CXXRD = T->getAsCXXRecordDecl();
if (CXXRD && CXXRD->hasUserDeclaredConstructor()) {
// Don't warn if there's an equivalent default constructor that would be
// used instead.
bool HasEquivCtor = false;
if (IList->getNumInits() == 0) {
auto *CD = SemaRef.LookupDefaultConstructor(CXXRD);
HasEquivCtor = CD && !CD->isDeleted();
}
if (!HasEquivCtor) {
SemaRef.Diag(IList->getBeginLoc(),
diag::warn_cxx20_compat_aggregate_init_with_ctors)
<< IList->getSourceRange() << T;
}
}
}
}
void InitListChecker::CheckListElementTypes(const InitializedEntity &Entity,
InitListExpr *IList,
QualType &DeclType,
bool SubobjectIsDesignatorContext,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex,
bool TopLevelObject) {
if (DeclType->isAnyComplexType() && SubobjectIsDesignatorContext) {
// Explicitly braced initializer for complex type can be real+imaginary
// parts.
CheckComplexType(Entity, IList, DeclType, Index,
StructuredList, StructuredIndex);
} else if (DeclType->isScalarType()) {
CheckScalarType(Entity, IList, DeclType, Index,
StructuredList, StructuredIndex);
} else if (DeclType->isVectorType()) {
CheckVectorType(Entity, IList, DeclType, Index,
StructuredList, StructuredIndex);
} else if (DeclType->isRecordType()) {
assert(DeclType->isAggregateType() &&
"non-aggregate records should be handed in CheckSubElementType");
RecordDecl *RD = DeclType->castAs<RecordType>()->getDecl();
auto Bases =
CXXRecordDecl::base_class_range(CXXRecordDecl::base_class_iterator(),
CXXRecordDecl::base_class_iterator());
if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD))
Bases = CXXRD->bases();
CheckStructUnionTypes(Entity, IList, DeclType, Bases, RD->field_begin(),
SubobjectIsDesignatorContext, Index, StructuredList,
StructuredIndex, TopLevelObject);
} else if (DeclType->isArrayType()) {
llvm::APSInt Zero(
SemaRef.Context.getTypeSize(SemaRef.Context.getSizeType()),
false);
CheckArrayType(Entity, IList, DeclType, Zero,
SubobjectIsDesignatorContext, Index,
StructuredList, StructuredIndex);
} else if (DeclType->isVoidType() || DeclType->isFunctionType()) {
// This type is invalid, issue a diagnostic.
++Index;
if (!VerifyOnly)
SemaRef.Diag(IList->getBeginLoc(), diag::err_illegal_initializer_type)
<< DeclType;
hadError = true;
} else if (DeclType->isReferenceType()) {
CheckReferenceType(Entity, IList, DeclType, Index,
StructuredList, StructuredIndex);
} else if (DeclType->isObjCObjectType()) {
if (!VerifyOnly)
SemaRef.Diag(IList->getBeginLoc(), diag::err_init_objc_class) << DeclType;
hadError = true;
} else if (DeclType->isOCLIntelSubgroupAVCType() ||
DeclType->isSizelessBuiltinType()) {
// Checks for scalar type are sufficient for these types too.
CheckScalarType(Entity, IList, DeclType, Index, StructuredList,
StructuredIndex);
} else {
if (!VerifyOnly)
SemaRef.Diag(IList->getBeginLoc(), diag::err_illegal_initializer_type)
<< DeclType;
hadError = true;
}
}
void InitListChecker::CheckSubElementType(const InitializedEntity &Entity,
InitListExpr *IList,
QualType ElemType,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex) {
Expr *expr = IList->getInit(Index);
if (ElemType->isReferenceType())
return CheckReferenceType(Entity, IList, ElemType, Index,
StructuredList, StructuredIndex);
if (InitListExpr *SubInitList = dyn_cast<InitListExpr>(expr)) {
if (SubInitList->getNumInits() == 1 &&
IsStringInit(SubInitList->getInit(0), ElemType, SemaRef.Context) ==
SIF_None) {
// FIXME: It would be more faithful and no less correct to include an
// InitListExpr in the semantic form of the initializer list in this case.
expr = SubInitList->getInit(0);
}
// Nested aggregate initialization and C++ initialization are handled later.
} else if (isa<ImplicitValueInitExpr>(expr)) {
// This happens during template instantiation when we see an InitListExpr
// that we've already checked once.
assert(SemaRef.Context.hasSameType(expr->getType(), ElemType) &&
"found implicit initialization for the wrong type");
UpdateStructuredListElement(StructuredList, StructuredIndex, expr);
++Index;
return;
}
if (SemaRef.getLangOpts().CPlusPlus || isa<InitListExpr>(expr)) {
// C++ [dcl.init.aggr]p2:
// Each member is copy-initialized from the corresponding
// initializer-clause.
// FIXME: Better EqualLoc?
InitializationKind Kind =
InitializationKind::CreateCopy(expr->getBeginLoc(), SourceLocation());
// Vector elements can be initialized from other vectors in which case
// we need initialization entity with a type of a vector (and not a vector
// element!) initializing multiple vector elements.
auto TmpEntity =
(ElemType->isExtVectorType() && !Entity.getType()->isExtVectorType())
? InitializedEntity::InitializeTemporary(ElemType)
: Entity;
InitializationSequence Seq(SemaRef, TmpEntity, Kind, expr,
/*TopLevelOfInitList*/ true);
// C++14 [dcl.init.aggr]p13:
// If the assignment-expression can initialize a member, the member is
// initialized. Otherwise [...] brace elision is assumed
//
// Brace elision is never performed if the element is not an
// assignment-expression.
if (Seq || isa<InitListExpr>(expr)) {
if (!VerifyOnly) {
ExprResult Result = Seq.Perform(SemaRef, TmpEntity, Kind, expr);
if (Result.isInvalid())
hadError = true;
UpdateStructuredListElement(StructuredList, StructuredIndex,
Result.getAs<Expr>());
} else if (!Seq) {
hadError = true;
} else if (StructuredList) {
UpdateStructuredListElement(StructuredList, StructuredIndex,
getDummyInit());
}
++Index;
return;
}
// Fall through for subaggregate initialization
} else if (ElemType->isScalarType() || ElemType->isAtomicType()) {
// FIXME: Need to handle atomic aggregate types with implicit init lists.
return CheckScalarType(Entity, IList, ElemType, Index,
StructuredList, StructuredIndex);
} else if (const ArrayType *arrayType =
SemaRef.Context.getAsArrayType(ElemType)) {
// arrayType can be incomplete if we're initializing a flexible
// array member. There's nothing we can do with the completed
// type here, though.
if (IsStringInit(expr, arrayType, SemaRef.Context) == SIF_None) {
// FIXME: Should we do this checking in verify-only mode?
if (!VerifyOnly)
CheckStringInit(expr, ElemType, arrayType, SemaRef);
if (StructuredList)
UpdateStructuredListElement(StructuredList, StructuredIndex, expr);
++Index;
return;
}
// Fall through for subaggregate initialization.
} else {
assert((ElemType->isRecordType() || ElemType->isVectorType() ||
ElemType->isOpenCLSpecificType()) && "Unexpected type");
// C99 6.7.8p13:
//
// The initializer for a structure or union object that has
// automatic storage duration shall be either an initializer
// list as described below, or a single expression that has
// compatible structure or union type. In the latter case, the
// initial value of the object, including unnamed members, is
// that of the expression.
ExprResult ExprRes = expr;
if (SemaRef.CheckSingleAssignmentConstraints(
ElemType, ExprRes, !VerifyOnly) != Sema::Incompatible) {
if (ExprRes.isInvalid())
hadError = true;
else {
ExprRes = SemaRef.DefaultFunctionArrayLvalueConversion(ExprRes.get());
if (ExprRes.isInvalid())
hadError = true;
}
UpdateStructuredListElement(StructuredList, StructuredIndex,
ExprRes.getAs<Expr>());
++Index;
return;
}
ExprRes.get();
// Fall through for subaggregate initialization
}
// C++ [dcl.init.aggr]p12:
//
// [...] Otherwise, if the member is itself a non-empty
// subaggregate, brace elision is assumed and the initializer is
// considered for the initialization of the first member of
// the subaggregate.
// OpenCL vector initializer is handled elsewhere.
if ((!SemaRef.getLangOpts().OpenCL && ElemType->isVectorType()) ||
ElemType->isAggregateType()) {
CheckImplicitInitList(Entity, IList, ElemType, Index, StructuredList,
StructuredIndex);
++StructuredIndex;
} else {
if (!VerifyOnly) {
// We cannot initialize this element, so let PerformCopyInitialization
// produce the appropriate diagnostic. We already checked that this
// initialization will fail.
ExprResult Copy =
SemaRef.PerformCopyInitialization(Entity, SourceLocation(), expr,
/*TopLevelOfInitList=*/true);
(void)Copy;
assert(Copy.isInvalid() &&
"expected non-aggregate initialization to fail");
}
hadError = true;
++Index;
++StructuredIndex;
}
}
void InitListChecker::CheckComplexType(const InitializedEntity &Entity,
InitListExpr *IList, QualType DeclType,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex) {
assert(Index == 0 && "Index in explicit init list must be zero");
// As an extension, clang supports complex initializers, which initialize
// a complex number component-wise. When an explicit initializer list for
// a complex number contains two two initializers, this extension kicks in:
// it exepcts the initializer list to contain two elements convertible to
// the element type of the complex type. The first element initializes
// the real part, and the second element intitializes the imaginary part.
if (IList->getNumInits() != 2)
return CheckScalarType(Entity, IList, DeclType, Index, StructuredList,
StructuredIndex);
// This is an extension in C. (The builtin _Complex type does not exist
// in the C++ standard.)
if (!SemaRef.getLangOpts().CPlusPlus && !VerifyOnly)
SemaRef.Diag(IList->getBeginLoc(), diag::ext_complex_component_init)
<< IList->getSourceRange();
// Initialize the complex number.
QualType elementType = DeclType->castAs<ComplexType>()->getElementType();
InitializedEntity ElementEntity =
InitializedEntity::InitializeElement(SemaRef.Context, 0, Entity);
for (unsigned i = 0; i < 2; ++i) {
ElementEntity.setElementIndex(Index);
CheckSubElementType(ElementEntity, IList, elementType, Index,
StructuredList, StructuredIndex);
}
}
void InitListChecker::CheckScalarType(const InitializedEntity &Entity,
InitListExpr *IList, QualType DeclType,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex) {
if (Index >= IList->getNumInits()) {
if (!VerifyOnly) {
if (DeclType->isSizelessBuiltinType())
SemaRef.Diag(IList->getBeginLoc(),
SemaRef.getLangOpts().CPlusPlus11
? diag::warn_cxx98_compat_empty_sizeless_initializer
: diag::err_empty_sizeless_initializer)
<< DeclType << IList->getSourceRange();
else
SemaRef.Diag(IList->getBeginLoc(),
SemaRef.getLangOpts().CPlusPlus11
? diag::warn_cxx98_compat_empty_scalar_initializer
: diag::err_empty_scalar_initializer)
<< IList->getSourceRange();
}
hadError = !SemaRef.getLangOpts().CPlusPlus11;
++Index;
++StructuredIndex;
return;
}
Expr *expr = IList->getInit(Index);
if (InitListExpr *SubIList = dyn_cast<InitListExpr>(expr)) {
// FIXME: This is invalid, and accepting it causes overload resolution
// to pick the wrong overload in some corner cases.
if (!VerifyOnly)
SemaRef.Diag(SubIList->getBeginLoc(), diag::ext_many_braces_around_init)
<< DeclType->isSizelessBuiltinType() << SubIList->getSourceRange();
CheckScalarType(Entity, SubIList, DeclType, Index, StructuredList,
StructuredIndex);
return;
} else if (isa<DesignatedInitExpr>(expr)) {
if (!VerifyOnly)
SemaRef.Diag(expr->getBeginLoc(),
diag::err_designator_for_scalar_or_sizeless_init)
<< DeclType->isSizelessBuiltinType() << DeclType
<< expr->getSourceRange();
hadError = true;
++Index;
++StructuredIndex;
return;
}
ExprResult Result;
if (VerifyOnly) {
if (SemaRef.CanPerformCopyInitialization(Entity, expr))
Result = getDummyInit();
else
Result = ExprError();
} else {
Result =
SemaRef.PerformCopyInitialization(Entity, expr->getBeginLoc(), expr,
/*TopLevelOfInitList=*/true);
}
Expr *ResultExpr = nullptr;
if (Result.isInvalid())
hadError = true; // types weren't compatible.
else {
ResultExpr = Result.getAs<Expr>();
if (ResultExpr != expr && !VerifyOnly) {
// The type was promoted, update initializer list.
// FIXME: Why are we updating the syntactic init list?
IList->setInit(Index, ResultExpr);
}
}
UpdateStructuredListElement(StructuredList, StructuredIndex, ResultExpr);
++Index;
}
void InitListChecker::CheckReferenceType(const InitializedEntity &Entity,
InitListExpr *IList, QualType DeclType,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex) {
if (Index >= IList->getNumInits()) {
// FIXME: It would be wonderful if we could point at the actual member. In
// general, it would be useful to pass location information down the stack,
// so that we know the location (or decl) of the "current object" being
// initialized.
if (!VerifyOnly)
SemaRef.Diag(IList->getBeginLoc(),
diag::err_init_reference_member_uninitialized)
<< DeclType << IList->getSourceRange();
hadError = true;
++Index;
++StructuredIndex;
return;
}
Expr *expr = IList->getInit(Index);
if (isa<InitListExpr>(expr) && !SemaRef.getLangOpts().CPlusPlus11) {
if (!VerifyOnly)
SemaRef.Diag(IList->getBeginLoc(), diag::err_init_non_aggr_init_list)
<< DeclType << IList->getSourceRange();
hadError = true;
++Index;
++StructuredIndex;
return;
}
ExprResult Result;
if (VerifyOnly) {
if (SemaRef.CanPerformCopyInitialization(Entity,expr))
Result = getDummyInit();
else
Result = ExprError();
} else {
Result =
SemaRef.PerformCopyInitialization(Entity, expr->getBeginLoc(), expr,
/*TopLevelOfInitList=*/true);
}
if (Result.isInvalid())
hadError = true;
expr = Result.getAs<Expr>();
// FIXME: Why are we updating the syntactic init list?
if (!VerifyOnly && expr)
IList->setInit(Index, expr);
UpdateStructuredListElement(StructuredList, StructuredIndex, expr);
++Index;
}
void InitListChecker::CheckVectorType(const InitializedEntity &Entity,
InitListExpr *IList, QualType DeclType,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex) {
const VectorType *VT = DeclType->castAs<VectorType>();
unsigned maxElements = VT->getNumElements();
unsigned numEltsInit = 0;
QualType elementType = VT->getElementType();
if (Index >= IList->getNumInits()) {
// Make sure the element type can be value-initialized.
CheckEmptyInitializable(
InitializedEntity::InitializeElement(SemaRef.Context, 0, Entity),
IList->getEndLoc());
return;
}
if (!SemaRef.getLangOpts().OpenCL) {
// If the initializing element is a vector, try to copy-initialize
// instead of breaking it apart (which is doomed to failure anyway).
Expr *Init = IList->getInit(Index);
if (!isa<InitListExpr>(Init) && Init->getType()->isVectorType()) {
ExprResult Result;
if (VerifyOnly) {
if (SemaRef.CanPerformCopyInitialization(Entity, Init))
Result = getDummyInit();
else
Result = ExprError();
} else {
Result =
SemaRef.PerformCopyInitialization(Entity, Init->getBeginLoc(), Init,
/*TopLevelOfInitList=*/true);
}
Expr *ResultExpr = nullptr;
if (Result.isInvalid())
hadError = true; // types weren't compatible.
else {
ResultExpr = Result.getAs<Expr>();
if (ResultExpr != Init && !VerifyOnly) {
// The type was promoted, update initializer list.
// FIXME: Why are we updating the syntactic init list?
IList->setInit(Index, ResultExpr);
}
}
UpdateStructuredListElement(StructuredList, StructuredIndex, ResultExpr);
++Index;
return;
}
InitializedEntity ElementEntity =
InitializedEntity::InitializeElement(SemaRef.Context, 0, Entity);
for (unsigned i = 0; i < maxElements; ++i, ++numEltsInit) {
// Don't attempt to go past the end of the init list
if (Index >= IList->getNumInits()) {
CheckEmptyInitializable(ElementEntity, IList->getEndLoc());
break;
}
ElementEntity.setElementIndex(Index);
CheckSubElementType(ElementEntity, IList, elementType, Index,
StructuredList, StructuredIndex);
}
if (VerifyOnly)
return;
bool isBigEndian = SemaRef.Context.getTargetInfo().isBigEndian();
const VectorType *T = Entity.getType()->castAs<VectorType>();
if (isBigEndian && (T->getVectorKind() == VectorType::NeonVector ||
T->getVectorKind() == VectorType::NeonPolyVector)) {
// The ability to use vector initializer lists is a GNU vector extension
// and is unrelated to the NEON intrinsics in arm_neon.h. On little
// endian machines it works fine, however on big endian machines it
// exhibits surprising behaviour:
//
// uint32x2_t x = {42, 64};
// return vget_lane_u32(x, 0); // Will return 64.
//
// Because of this, explicitly call out that it is non-portable.
//
SemaRef.Diag(IList->getBeginLoc(),
diag::warn_neon_vector_initializer_non_portable);
const char *typeCode;
unsigned typeSize = SemaRef.Context.getTypeSize(elementType);
if (elementType->isFloatingType())
typeCode = "f";
else if (elementType->isSignedIntegerType())
typeCode = "s";
else if (elementType->isUnsignedIntegerType())
typeCode = "u";
else
llvm_unreachable("Invalid element type!");
SemaRef.Diag(IList->getBeginLoc(),
SemaRef.Context.getTypeSize(VT) > 64
? diag::note_neon_vector_initializer_non_portable_q
: diag::note_neon_vector_initializer_non_portable)
<< typeCode << typeSize;
}
return;
}
InitializedEntity ElementEntity =
InitializedEntity::InitializeElement(SemaRef.Context, 0, Entity);
// OpenCL initializers allows vectors to be constructed from vectors.
for (unsigned i = 0; i < maxElements; ++i) {
// Don't attempt to go past the end of the init list
if (Index >= IList->getNumInits())
break;
ElementEntity.setElementIndex(Index);
QualType IType = IList->getInit(Index)->getType();
if (!IType->isVectorType()) {
CheckSubElementType(ElementEntity, IList, elementType, Index,
StructuredList, StructuredIndex);
++numEltsInit;
} else {
QualType VecType;
const VectorType *IVT = IType->castAs<VectorType>();
unsigned numIElts = IVT->getNumElements();
if (IType->isExtVectorType())
VecType = SemaRef.Context.getExtVectorType(elementType, numIElts);
else
VecType = SemaRef.Context.getVectorType(elementType, numIElts,
IVT->getVectorKind());
CheckSubElementType(ElementEntity, IList, VecType, Index,
StructuredList, StructuredIndex);
numEltsInit += numIElts;
}
}
// OpenCL requires all elements to be initialized.
if (numEltsInit != maxElements) {
if (!VerifyOnly)
SemaRef.Diag(IList->getBeginLoc(),
diag::err_vector_incorrect_num_initializers)
<< (numEltsInit < maxElements) << maxElements << numEltsInit;
hadError = true;
}
}
/// Check if the type of a class element has an accessible destructor, and marks
/// it referenced. Returns true if we shouldn't form a reference to the
/// destructor.
///
/// Aggregate initialization requires a class element's destructor be
/// accessible per 11.6.1 [dcl.init.aggr]:
///
/// The destructor for each element of class type is potentially invoked
/// (15.4 [class.dtor]) from the context where the aggregate initialization
/// occurs.
static bool checkDestructorReference(QualType ElementType, SourceLocation Loc,
Sema &SemaRef) {
auto *CXXRD = ElementType->getAsCXXRecordDecl();
if (!CXXRD)
return false;
CXXDestructorDecl *Destructor = SemaRef.LookupDestructor(CXXRD);
SemaRef.CheckDestructorAccess(Loc, Destructor,
SemaRef.PDiag(diag::err_access_dtor_temp)
<< ElementType);
SemaRef.MarkFunctionReferenced(Loc, Destructor);
return SemaRef.DiagnoseUseOfDecl(Destructor, Loc);
}
void InitListChecker::CheckArrayType(const InitializedEntity &Entity,
InitListExpr *IList, QualType &DeclType,
llvm::APSInt elementIndex,
bool SubobjectIsDesignatorContext,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex) {
const ArrayType *arrayType = SemaRef.Context.getAsArrayType(DeclType);
if (!VerifyOnly) {
if (checkDestructorReference(arrayType->getElementType(),
IList->getEndLoc(), SemaRef)) {
hadError = true;
return;
}
}
// Check for the special-case of initializing an array with a string.
if (Index < IList->getNumInits()) {
if (IsStringInit(IList->getInit(Index), arrayType, SemaRef.Context) ==
SIF_None) {
// We place the string literal directly into the resulting
// initializer list. This is the only place where the structure
// of the structured initializer list doesn't match exactly,
// because doing so would involve allocating one character
// constant for each string.
// FIXME: Should we do these checks in verify-only mode too?
if (!VerifyOnly)
CheckStringInit(IList->getInit(Index), DeclType, arrayType, SemaRef);
if (StructuredList) {
UpdateStructuredListElement(StructuredList, StructuredIndex,
IList->getInit(Index));
StructuredList->resizeInits(SemaRef.Context, StructuredIndex);
}
++Index;
return;
}
}
if (const VariableArrayType *VAT = dyn_cast<VariableArrayType>(arrayType)) {
// Check for VLAs; in standard C it would be possible to check this
// earlier, but I don't know where clang accepts VLAs (gcc accepts
// them in all sorts of strange places).
if (!VerifyOnly)
SemaRef.Diag(VAT->getSizeExpr()->getBeginLoc(),
diag::err_variable_object_no_init)
<< VAT->getSizeExpr()->getSourceRange();
hadError = true;
++Index;
++StructuredIndex;
return;
}
// We might know the maximum number of elements in advance.
llvm::APSInt maxElements(elementIndex.getBitWidth(),
elementIndex.isUnsigned());
bool maxElementsKnown = false;
if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(arrayType)) {
maxElements = CAT->getSize();
elementIndex = elementIndex.extOrTrunc(maxElements.getBitWidth());
elementIndex.setIsUnsigned(maxElements.isUnsigned());
maxElementsKnown = true;
}
QualType elementType = arrayType->getElementType();
while (Index < IList->getNumInits()) {
Expr *Init = IList->getInit(Index);
if (DesignatedInitExpr *DIE = dyn_cast<DesignatedInitExpr>(Init)) {
// If we're not the subobject that matches up with the '{' for
// the designator, we shouldn't be handling the
// designator. Return immediately.
if (!SubobjectIsDesignatorContext)
return;
// Handle this designated initializer. elementIndex will be
// updated to be the next array element we'll initialize.
if (CheckDesignatedInitializer(Entity, IList, DIE, 0,
DeclType, nullptr, &elementIndex, Index,
StructuredList, StructuredIndex, true,
false)) {
hadError = true;
continue;
}
if (elementIndex.getBitWidth() > maxElements.getBitWidth())
maxElements = maxElements.extend(elementIndex.getBitWidth());
else if (elementIndex.getBitWidth() < maxElements.getBitWidth())
elementIndex = elementIndex.extend(maxElements.getBitWidth());
elementIndex.setIsUnsigned(maxElements.isUnsigned());
// If the array is of incomplete type, keep track of the number of
// elements in the initializer.
if (!maxElementsKnown && elementIndex > maxElements)
maxElements = elementIndex;
continue;
}
// If we know the maximum number of elements, and we've already
// hit it, stop consuming elements in the initializer list.
if (maxElementsKnown && elementIndex == maxElements)
break;
InitializedEntity ElementEntity =
InitializedEntity::InitializeElement(SemaRef.Context, StructuredIndex,
Entity);
// Check this element.
CheckSubElementType(ElementEntity, IList, elementType, Index,
StructuredList, StructuredIndex);
++elementIndex;
// If the array is of incomplete type, keep track of the number of
// elements in the initializer.
if (!maxElementsKnown && elementIndex > maxElements)
maxElements = elementIndex;
}
if (!hadError && DeclType->isIncompleteArrayType() && !VerifyOnly) {
// If this is an incomplete array type, the actual type needs to
// be calculated here.
llvm::APSInt Zero(maxElements.getBitWidth(), maxElements.isUnsigned());
if (maxElements == Zero && !Entity.isVariableLengthArrayNew()) {
// Sizing an array implicitly to zero is not allowed by ISO C,
// but is supported by GNU.
SemaRef.Diag(IList->getBeginLoc(), diag::ext_typecheck_zero_array_size);
}
DeclType = SemaRef.Context.getConstantArrayType(
elementType, maxElements, nullptr, ArrayType::Normal, 0);
}
if (!hadError) {
// If there are any members of the array that get value-initialized, check
// that is possible. That happens if we know the bound and don't have
// enough elements, or if we're performing an array new with an unknown
// bound.
if ((maxElementsKnown && elementIndex < maxElements) ||
Entity.isVariableLengthArrayNew())
CheckEmptyInitializable(
InitializedEntity::InitializeElement(SemaRef.Context, 0, Entity),
IList->getEndLoc());
}
}
bool InitListChecker::CheckFlexibleArrayInit(const InitializedEntity &Entity,
Expr *InitExpr,
FieldDecl *Field,
bool TopLevelObject) {
// Handle GNU flexible array initializers.
unsigned FlexArrayDiag;
if (isa<InitListExpr>(InitExpr) &&
cast<InitListExpr>(InitExpr)->getNumInits() == 0) {
// Empty flexible array init always allowed as an extension
FlexArrayDiag = diag::ext_flexible_array_init;
} else if (SemaRef.getLangOpts().CPlusPlus) {
// Disallow flexible array init in C++; it is not required for gcc
// compatibility, and it needs work to IRGen correctly in general.
FlexArrayDiag = diag::err_flexible_array_init;
} else if (!TopLevelObject) {
// Disallow flexible array init on non-top-level object
FlexArrayDiag = diag::err_flexible_array_init;
} else if (Entity.getKind() != InitializedEntity::EK_Variable) {
// Disallow flexible array init on anything which is not a variable.
FlexArrayDiag = diag::err_flexible_array_init;
} else if (cast<VarDecl>(Entity.getDecl())->hasLocalStorage()) {
// Disallow flexible array init on local variables.
FlexArrayDiag = diag::err_flexible_array_init;
} else {
// Allow other cases.
FlexArrayDiag = diag::ext_flexible_array_init;
}
if (!VerifyOnly) {
SemaRef.Diag(InitExpr->getBeginLoc(), FlexArrayDiag)
<< InitExpr->getBeginLoc();
SemaRef.Diag(Field->getLocation(), diag::note_flexible_array_member)
<< Field;
}
return FlexArrayDiag != diag::ext_flexible_array_init;
}
void InitListChecker::CheckStructUnionTypes(
const InitializedEntity &Entity, InitListExpr *IList, QualType DeclType,
CXXRecordDecl::base_class_range Bases, RecordDecl::field_iterator Field,
bool SubobjectIsDesignatorContext, unsigned &Index,
InitListExpr *StructuredList, unsigned &StructuredIndex,
bool TopLevelObject) {
RecordDecl *structDecl = DeclType->castAs<RecordType>()->getDecl();
// If the record is invalid, some of it's members are invalid. To avoid
// confusion, we forgo checking the intializer for the entire record.
if (structDecl->isInvalidDecl()) {
// Assume it was supposed to consume a single initializer.
++Index;
hadError = true;
return;
}
if (DeclType->isUnionType() && IList->getNumInits() == 0) {
RecordDecl *RD = DeclType->castAs<RecordType>()->getDecl();
if (!VerifyOnly)
for (FieldDecl *FD : RD->fields()) {
QualType ET = SemaRef.Context.getBaseElementType(FD->getType());
if (checkDestructorReference(ET, IList->getEndLoc(), SemaRef)) {
hadError = true;
return;
}
}
// If there's a default initializer, use it.
if (isa<CXXRecordDecl>(RD) &&
cast<CXXRecordDecl>(RD)->hasInClassInitializer()) {
if (!StructuredList)
return;
for (RecordDecl::field_iterator FieldEnd = RD->field_end();
Field != FieldEnd; ++Field) {
if (Field->hasInClassInitializer()) {
StructuredList->setInitializedFieldInUnion(*Field);
// FIXME: Actually build a CXXDefaultInitExpr?
return;
}
}
}
// Value-initialize the first member of the union that isn't an unnamed
// bitfield.
for (RecordDecl::field_iterator FieldEnd = RD->field_end();
Field != FieldEnd; ++Field) {
if (!Field->isUnnamedBitfield()) {
CheckEmptyInitializable(
InitializedEntity::InitializeMember(*Field, &Entity),
IList->getEndLoc());
if (StructuredList)
StructuredList->setInitializedFieldInUnion(*Field);
break;
}
}
return;
}
bool InitializedSomething = false;
// If we have any base classes, they are initialized prior to the fields.
for (auto &Base : Bases) {
Expr *Init = Index < IList->getNumInits() ? IList->getInit(Index) : nullptr;
// Designated inits always initialize fields, so if we see one, all
// remaining base classes have no explicit initializer.
if (Init && isa<DesignatedInitExpr>(Init))
Init = nullptr;
SourceLocation InitLoc = Init ? Init->getBeginLoc() : IList->getEndLoc();
InitializedEntity BaseEntity = InitializedEntity::InitializeBase(
SemaRef.Context, &Base, false, &Entity);
if (Init) {
CheckSubElementType(BaseEntity, IList, Base.getType(), Index,
StructuredList, StructuredIndex);
InitializedSomething = true;
} else {
CheckEmptyInitializable(BaseEntity, InitLoc);
}
if (!VerifyOnly)
if (checkDestructorReference(Base.getType(), InitLoc, SemaRef)) {
hadError = true;
return;
}
}
// If structDecl is a forward declaration, this loop won't do
// anything except look at designated initializers; That's okay,
// because an error should get printed out elsewhere. It might be
// worthwhile to skip over the rest of the initializer, though.
RecordDecl *RD = DeclType->castAs<RecordType>()->getDecl();
RecordDecl::field_iterator FieldEnd = RD->field_end();
bool CheckForMissingFields =
!IList->isIdiomaticZeroInitializer(SemaRef.getLangOpts());
bool HasDesignatedInit = false;
while (Index < IList->getNumInits()) {
Expr *Init = IList->getInit(Index);
SourceLocation InitLoc = Init->getBeginLoc();
if (DesignatedInitExpr *DIE = dyn_cast<DesignatedInitExpr>(Init)) {
// If we're not the subobject that matches up with the '{' for
// the designator, we shouldn't be handling the
// designator. Return immediately.
if (!SubobjectIsDesignatorContext)
return;
HasDesignatedInit = true;
// Handle this designated initializer. Field will be updated to
// the next field that we'll be initializing.
if (CheckDesignatedInitializer(Entity, IList, DIE, 0,
DeclType, &Field, nullptr, Index,
StructuredList, StructuredIndex,
true, TopLevelObject))
hadError = true;
else if (!VerifyOnly) {
// Find the field named by the designated initializer.
RecordDecl::field_iterator F = RD->field_begin();
while (std::next(F) != Field)
++F;
QualType ET = SemaRef.Context.getBaseElementType(F->getType());
if (checkDestructorReference(ET, InitLoc, SemaRef)) {
hadError = true;
return;
}
}
InitializedSomething = true;
// Disable check for missing fields when designators are used.
// This matches gcc behaviour.
CheckForMissingFields = false;
continue;
}
if (Field == FieldEnd) {
// We've run out of fields. We're done.
break;
}
// We've already initialized a member of a union. We're done.
if (InitializedSomething && DeclType->isUnionType())
break;
// If we've hit the flexible array member at the end, we're done.
if (Field->getType()->isIncompleteArrayType())
break;
if (Field->isUnnamedBitfield()) {
// Don't initialize unnamed bitfields, e.g. "int : 20;"
++Field;
continue;
}
// Make sure we can use this declaration.
bool InvalidUse;
if (VerifyOnly)
InvalidUse = !SemaRef.CanUseDecl(*Field, TreatUnavailableAsInvalid);
else
InvalidUse = SemaRef.DiagnoseUseOfDecl(
*Field, IList->getInit(Index)->getBeginLoc());
if (InvalidUse) {
++Index;
++Field;
hadError = true;
continue;
}
if (!VerifyOnly) {
QualType ET = SemaRef.Context.getBaseElementType(Field->getType());
if (checkDestructorReference(ET, InitLoc, SemaRef)) {
hadError = true;
return;
}
}
InitializedEntity MemberEntity =
InitializedEntity::InitializeMember(*Field, &Entity);
CheckSubElementType(MemberEntity, IList, Field->getType(), Index,
StructuredList, StructuredIndex);
InitializedSomething = true;
if (DeclType->isUnionType() && StructuredList) {
// Initialize the first field within the union.
StructuredList->setInitializedFieldInUnion(*Field);
}
++Field;
}
// Emit warnings for missing struct field initializers.
if (!VerifyOnly && InitializedSomething && CheckForMissingFields &&
Field != FieldEnd && !Field->getType()->isIncompleteArrayType() &&
!DeclType->isUnionType()) {
// It is possible we have one or more unnamed bitfields remaining.
// Find first (if any) named field and emit warning.
for (RecordDecl::field_iterator it = Field, end = RD->field_end();
it != end; ++it) {
if (!it->isUnnamedBitfield() && !it->hasInClassInitializer()) {
SemaRef.Diag(IList->getSourceRange().getEnd(),
diag::warn_missing_field_initializers) << *it;
break;
}
}
}
// Check that any remaining fields can be value-initialized if we're not
// building a structured list. (If we are, we'll check this later.)
if (!StructuredList && Field != FieldEnd && !DeclType->isUnionType() &&
!Field->getType()->isIncompleteArrayType()) {
for (; Field != FieldEnd && !hadError; ++Field) {
if (!Field->isUnnamedBitfield() && !Field->hasInClassInitializer())
CheckEmptyInitializable(
InitializedEntity::InitializeMember(*Field, &Entity),
IList->getEndLoc());
}
}
// Check that the types of the remaining fields have accessible destructors.
if (!VerifyOnly) {
// If the initializer expression has a designated initializer, check the
// elements for which a designated initializer is not provided too.
RecordDecl::field_iterator I = HasDesignatedInit ? RD->field_begin()
: Field;
for (RecordDecl::field_iterator E = RD->field_end(); I != E; ++I) {
QualType ET = SemaRef.Context.getBaseElementType(I->getType());
if (checkDestructorReference(ET, IList->getEndLoc(), SemaRef)) {
hadError = true;
return;
}
}
}
if (Field == FieldEnd || !Field->getType()->isIncompleteArrayType() ||
Index >= IList->getNumInits())
return;
if (CheckFlexibleArrayInit(Entity, IList->getInit(Index), *Field,
TopLevelObject)) {
hadError = true;
++Index;
return;
}
InitializedEntity MemberEntity =
InitializedEntity::InitializeMember(*Field, &Entity);
if (isa<InitListExpr>(IList->getInit(Index)))
CheckSubElementType(MemberEntity, IList, Field->getType(), Index,
StructuredList, StructuredIndex);
else
CheckImplicitInitList(MemberEntity, IList, Field->getType(), Index,
StructuredList, StructuredIndex);
}
/// Expand a field designator that refers to a member of an
/// anonymous struct or union into a series of field designators that
/// refers to the field within the appropriate subobject.
///
static void ExpandAnonymousFieldDesignator(Sema &SemaRef,
DesignatedInitExpr *DIE,
unsigned DesigIdx,
IndirectFieldDecl *IndirectField) {
typedef DesignatedInitExpr::Designator Designator;
// Build the replacement designators.
SmallVector<Designator, 4> Replacements;
for (IndirectFieldDecl::chain_iterator PI = IndirectField->chain_begin(),
PE = IndirectField->chain_end(); PI != PE; ++PI) {
if (PI + 1 == PE)
Replacements.push_back(Designator((IdentifierInfo *)nullptr,
DIE->getDesignator(DesigIdx)->getDotLoc(),
DIE->getDesignator(DesigIdx)->getFieldLoc()));
else
Replacements.push_back(Designator((IdentifierInfo *)nullptr,
SourceLocation(), SourceLocation()));
assert(isa<FieldDecl>(*PI));
Replacements.back().setField(cast<FieldDecl>(*PI));
}
// Expand the current designator into the set of replacement
// designators, so we have a full subobject path down to where the
// member of the anonymous struct/union is actually stored.
DIE->ExpandDesignator(SemaRef.Context, DesigIdx, &Replacements[0],
&Replacements[0] + Replacements.size());
}
static DesignatedInitExpr *CloneDesignatedInitExpr(Sema &SemaRef,
DesignatedInitExpr *DIE) {
unsigned NumIndexExprs = DIE->getNumSubExprs() - 1;
SmallVector<Expr*, 4> IndexExprs(NumIndexExprs);
for (unsigned I = 0; I < NumIndexExprs; ++I)
IndexExprs[I] = DIE->getSubExpr(I + 1);
return DesignatedInitExpr::Create(SemaRef.Context, DIE->designators(),
IndexExprs,
DIE->getEqualOrColonLoc(),
DIE->usesGNUSyntax(), DIE->getInit());
}
namespace {
// Callback to only accept typo corrections that are for field members of
// the given struct or union.
class FieldInitializerValidatorCCC final : public CorrectionCandidateCallback {
public:
explicit FieldInitializerValidatorCCC(RecordDecl *RD)
: Record(RD) {}
bool ValidateCandidate(const TypoCorrection &candidate) override {
FieldDecl *FD = candidate.getCorrectionDeclAs<FieldDecl>();
return FD && FD->getDeclContext()->getRedeclContext()->Equals(Record);
}
std::unique_ptr<CorrectionCandidateCallback> clone() override {
return std::make_unique<FieldInitializerValidatorCCC>(*this);
}
private:
RecordDecl *Record;
};
} // end anonymous namespace
/// Check the well-formedness of a C99 designated initializer.
///
/// Determines whether the designated initializer @p DIE, which
/// resides at the given @p Index within the initializer list @p
/// IList, is well-formed for a current object of type @p DeclType
/// (C99 6.7.8). The actual subobject that this designator refers to
/// within the current subobject is returned in either
/// @p NextField or @p NextElementIndex (whichever is appropriate).
///
/// @param IList The initializer list in which this designated
/// initializer occurs.
///
/// @param DIE The designated initializer expression.
///
/// @param DesigIdx The index of the current designator.
///
/// @param CurrentObjectType The type of the "current object" (C99 6.7.8p17),
/// into which the designation in @p DIE should refer.
///
/// @param NextField If non-NULL and the first designator in @p DIE is
/// a field, this will be set to the field declaration corresponding
/// to the field named by the designator. On input, this is expected to be
/// the next field that would be initialized in the absence of designation,
/// if the complete object being initialized is a struct.
///
/// @param NextElementIndex If non-NULL and the first designator in @p
/// DIE is an array designator or GNU array-range designator, this
/// will be set to the last index initialized by this designator.
///
/// @param Index Index into @p IList where the designated initializer
/// @p DIE occurs.
///
/// @param StructuredList The initializer list expression that
/// describes all of the subobject initializers in the order they'll
/// actually be initialized.
///
/// @returns true if there was an error, false otherwise.
bool
InitListChecker::CheckDesignatedInitializer(const InitializedEntity &Entity,
InitListExpr *IList,
DesignatedInitExpr *DIE,
unsigned DesigIdx,
QualType &CurrentObjectType,
RecordDecl::field_iterator *NextField,
llvm::APSInt *NextElementIndex,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex,
bool FinishSubobjectInit,
bool TopLevelObject) {
if (DesigIdx == DIE->size()) {
// C++20 designated initialization can result in direct-list-initialization
// of the designated subobject. This is the only way that we can end up
// performing direct initialization as part of aggregate initialization, so
// it needs special handling.
if (DIE->isDirectInit()) {
Expr *Init = DIE->getInit();
assert(isa<InitListExpr>(Init) &&
"designator result in direct non-list initialization?");
InitializationKind Kind = InitializationKind::CreateDirectList(
DIE->getBeginLoc(), Init->getBeginLoc(), Init->getEndLoc());
InitializationSequence Seq(SemaRef, Entity, Kind, Init,
/*TopLevelOfInitList*/ true);
if (StructuredList) {
ExprResult Result = VerifyOnly
? getDummyInit()
: Seq.Perform(SemaRef, Entity, Kind, Init);
UpdateStructuredListElement(StructuredList, StructuredIndex,
Result.get());
}
++Index;
return !Seq;
}
// Check the actual initialization for the designated object type.
bool prevHadError = hadError;
// Temporarily remove the designator expression from the
// initializer list that the child calls see, so that we don't try
// to re-process the designator.
unsigned OldIndex = Index;
IList->setInit(OldIndex, DIE->getInit());
CheckSubElementType(Entity, IList, CurrentObjectType, Index,
StructuredList, StructuredIndex);
// Restore the designated initializer expression in the syntactic
// form of the initializer list.
if (IList->getInit(OldIndex) != DIE->getInit())
DIE->setInit(IList->getInit(OldIndex));
IList->setInit(OldIndex, DIE);
return hadError && !prevHadError;
}
DesignatedInitExpr::Designator *D = DIE->getDesignator(DesigIdx);
bool IsFirstDesignator = (DesigIdx == 0);
if (IsFirstDesignator ? FullyStructuredList : StructuredList) {
// Determine the structural initializer list that corresponds to the
// current subobject.
if (IsFirstDesignator)
StructuredList = FullyStructuredList;
else {
Expr *ExistingInit = StructuredIndex < StructuredList->getNumInits() ?
StructuredList->getInit(StructuredIndex) : nullptr;
if (!ExistingInit && StructuredList->hasArrayFiller())
ExistingInit = StructuredList->getArrayFiller();
if (!ExistingInit)
StructuredList = getStructuredSubobjectInit(
IList, Index, CurrentObjectType, StructuredList, StructuredIndex,
SourceRange(D->getBeginLoc(), DIE->getEndLoc()));
else if (InitListExpr *Result = dyn_cast<InitListExpr>(ExistingInit))
StructuredList = Result;
else {
// We are creating an initializer list that initializes the
// subobjects of the current object, but there was already an
// initialization that completely initialized the current
// subobject, e.g., by a compound literal:
//
// struct X { int a, b; };
// struct X xs[] = { [0] = (struct X) { 1, 2 }, [0].b = 3 };
//
// Here, xs[0].a == 1 and xs[0].b == 3, since the second,
// designated initializer re-initializes only its current object
// subobject [0].b.
diagnoseInitOverride(ExistingInit,
SourceRange(D->getBeginLoc(), DIE->getEndLoc()),
/*FullyOverwritten=*/false);
if (!VerifyOnly) {
if (DesignatedInitUpdateExpr *E =
dyn_cast<DesignatedInitUpdateExpr>(ExistingInit))
StructuredList = E->getUpdater();
else {
DesignatedInitUpdateExpr *DIUE = new (SemaRef.Context)
DesignatedInitUpdateExpr(SemaRef.Context, D->getBeginLoc(),
ExistingInit, DIE->getEndLoc());
StructuredList->updateInit(SemaRef.Context, StructuredIndex, DIUE);
StructuredList = DIUE->getUpdater();
}
} else {
// We don't need to track the structured representation of a
// designated init update of an already-fully-initialized object in
// verify-only mode. The only reason we would need the structure is
// to determine where the uninitialized "holes" are, and in this
// case, we know there aren't any and we can't introduce any.
StructuredList = nullptr;
}
}
}
}
if (D->isFieldDesignator()) {
// C99 6.7.8p7:
//
// If a designator has the form
//
// . identifier
//
// then the current object (defined below) shall have
// structure or union type and the identifier shall be the
// name of a member of that type.
const RecordType *RT = CurrentObjectType->getAs<RecordType>();
if (!RT) {
SourceLocation Loc = D->getDotLoc();
if (Loc.isInvalid())
Loc = D->getFieldLoc();
if (!VerifyOnly)
SemaRef.Diag(Loc, diag::err_field_designator_non_aggr)
<< SemaRef.getLangOpts().CPlusPlus << CurrentObjectType;
++Index;
return true;
}
FieldDecl *KnownField = D->getField();
if (!KnownField) {
IdentifierInfo *FieldName = D->getFieldName();
DeclContext::lookup_result Lookup = RT->getDecl()->lookup(FieldName);
for (NamedDecl *ND : Lookup) {
if (auto *FD = dyn_cast<FieldDecl>(ND)) {
KnownField = FD;
break;
}
if (auto *IFD = dyn_cast<IndirectFieldDecl>(ND)) {
// In verify mode, don't modify the original.
if (VerifyOnly)
DIE = CloneDesignatedInitExpr(SemaRef, DIE);
ExpandAnonymousFieldDesignator(SemaRef, DIE, DesigIdx, IFD);
D = DIE->getDesignator(DesigIdx);
KnownField = cast<FieldDecl>(*IFD->chain_begin());
break;
}
}
if (!KnownField) {
if (VerifyOnly) {
++Index;
return true; // No typo correction when just trying this out.
}
// Name lookup found something, but it wasn't a field.
if (!Lookup.empty()) {
SemaRef.Diag(D->getFieldLoc(), diag::err_field_designator_nonfield)
<< FieldName;
SemaRef.Diag(Lookup.front()->getLocation(),
diag::note_field_designator_found);
++Index;
return true;
}
// Name lookup didn't find anything.
// Determine whether this was a typo for another field name.
FieldInitializerValidatorCCC CCC(RT->getDecl());
if (TypoCorrection Corrected = SemaRef.CorrectTypo(
DeclarationNameInfo(FieldName, D->getFieldLoc()),
Sema::LookupMemberName, /*Scope=*/nullptr, /*SS=*/nullptr, CCC,
Sema::CTK_ErrorRecovery, RT->getDecl())) {
SemaRef.diagnoseTypo(
Corrected,
SemaRef.PDiag(diag::err_field_designator_unknown_suggest)
<< FieldName << CurrentObjectType);
KnownField = Corrected.getCorrectionDeclAs<FieldDecl>();
hadError = true;
} else {
// Typo correction didn't find anything.
SemaRef.Diag(D->getFieldLoc(), diag::err_field_designator_unknown)
<< FieldName << CurrentObjectType;
++Index;
return true;
}
}
}
unsigned NumBases = 0;
if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RT->getDecl()))
NumBases = CXXRD->getNumBases();
unsigned FieldIndex = NumBases;
for (auto *FI : RT->getDecl()->fields()) {
if (FI->isUnnamedBitfield())
continue;
if (declaresSameEntity(KnownField, FI)) {
KnownField = FI;
break;
}
++FieldIndex;
}
RecordDecl::field_iterator Field =
RecordDecl::field_iterator(DeclContext::decl_iterator(KnownField));
// All of the fields of a union are located at the same place in
// the initializer list.
if (RT->getDecl()->isUnion()) {
FieldIndex = 0;
if (StructuredList) {
FieldDecl *CurrentField = StructuredList->getInitializedFieldInUnion();
if (CurrentField && !declaresSameEntity(CurrentField, *Field)) {
assert(StructuredList->getNumInits() == 1
&& "A union should never have more than one initializer!");
Expr *ExistingInit = StructuredList->getInit(0);
if (ExistingInit) {
// We're about to throw away an initializer, emit warning.
diagnoseInitOverride(
ExistingInit, SourceRange(D->getBeginLoc(), DIE->getEndLoc()));
}
// remove existing initializer
StructuredList->resizeInits(SemaRef.Context, 0);
StructuredList->setInitializedFieldInUnion(nullptr);
}
StructuredList->setInitializedFieldInUnion(*Field);
}
}
// Make sure we can use this declaration.
bool InvalidUse;
if (VerifyOnly)
InvalidUse = !SemaRef.CanUseDecl(*Field, TreatUnavailableAsInvalid);
else
InvalidUse = SemaRef.DiagnoseUseOfDecl(*Field, D->getFieldLoc());
if (InvalidUse) {
++Index;
return true;
}
// C++20 [dcl.init.list]p3:
// The ordered identifiers in the designators of the designated-
// initializer-list shall form a subsequence of the ordered identifiers
// in the direct non-static data members of T.
//
// Note that this is not a condition on forming the aggregate
// initialization, only on actually performing initialization,
// so it is not checked in VerifyOnly mode.
//
// FIXME: This is the only reordering diagnostic we produce, and it only
// catches cases where we have a top-level field designator that jumps
// backwards. This is the only such case that is reachable in an
// otherwise-valid C++20 program, so is the only case that's required for
// conformance, but for consistency, we should diagnose all the other
// cases where a designator takes us backwards too.
if (IsFirstDesignator && !VerifyOnly && SemaRef.getLangOpts().CPlusPlus &&
NextField &&
(*NextField == RT->getDecl()->field_end() ||
(*NextField)->getFieldIndex() > Field->getFieldIndex() + 1)) {
// Find the field that we just initialized.
FieldDecl *PrevField = nullptr;
for (auto FI = RT->getDecl()->field_begin();
FI != RT->getDecl()->field_end(); ++FI) {
if (FI->isUnnamedBitfield())
continue;
if (*NextField != RT->getDecl()->field_end() &&
declaresSameEntity(*FI, **NextField))
break;
PrevField = *FI;
}
if (PrevField &&
PrevField->getFieldIndex() > KnownField->getFieldIndex()) {
SemaRef.Diag(DIE->getBeginLoc(), diag::ext_designated_init_reordered)
<< KnownField << PrevField << DIE->getSourceRange();
unsigned OldIndex = NumBases + PrevField->getFieldIndex();
if (StructuredList && OldIndex <= StructuredList->getNumInits()) {
if (Expr *PrevInit = StructuredList->getInit(OldIndex)) {
SemaRef.Diag(PrevInit->getBeginLoc(),
diag::note_previous_field_init)
<< PrevField << PrevInit->getSourceRange();
}
}
}
}
// Update the designator with the field declaration.
if (!VerifyOnly)
D->setField(*Field);
// Make sure that our non-designated initializer list has space
// for a subobject corresponding to this field.
if (StructuredList && FieldIndex >= StructuredList->getNumInits())
StructuredList->resizeInits(SemaRef.Context, FieldIndex + 1);
// This designator names a flexible array member.
if (Field->getType()->isIncompleteArrayType()) {
bool Invalid = false;
if ((DesigIdx + 1) != DIE->size()) {
// We can't designate an object within the flexible array
// member (because GCC doesn't allow it).
if (!VerifyOnly) {
DesignatedInitExpr::Designator *NextD
= DIE->getDesignator(DesigIdx + 1);
SemaRef.Diag(NextD->getBeginLoc(),
diag::err_designator_into_flexible_array_member)
<< SourceRange(NextD->getBeginLoc(), DIE->getEndLoc());
SemaRef.Diag(Field->getLocation(), diag::note_flexible_array_member)
<< *Field;
}
Invalid = true;
}
if (!hadError && !isa<InitListExpr>(DIE->getInit()) &&
!isa<StringLiteral>(DIE->getInit())) {
// The initializer is not an initializer list.
if (!VerifyOnly) {
SemaRef.Diag(DIE->getInit()->getBeginLoc(),
diag::err_flexible_array_init_needs_braces)
<< DIE->getInit()->getSourceRange();
SemaRef.Diag(Field->getLocation(), diag::note_flexible_array_member)
<< *Field;
}
Invalid = true;
}
// Check GNU flexible array initializer.
if (!Invalid && CheckFlexibleArrayInit(Entity, DIE->getInit(), *Field,
TopLevelObject))
Invalid = true;
if (Invalid) {
++Index;
return true;
}
// Initialize the array.
bool prevHadError = hadError;
unsigned newStructuredIndex = FieldIndex;
unsigned OldIndex = Index;
IList->setInit(Index, DIE->getInit());
InitializedEntity MemberEntity =
InitializedEntity::InitializeMember(*Field, &Entity);
CheckSubElementType(MemberEntity, IList, Field->getType(), Index,
StructuredList, newStructuredIndex);
IList->setInit(OldIndex, DIE);
if (hadError && !prevHadError) {
++Field;
++FieldIndex;
if (NextField)
*NextField = Field;
StructuredIndex = FieldIndex;
return true;
}
} else {
// Recurse to check later designated subobjects.
QualType FieldType = Field->getType();
unsigned newStructuredIndex = FieldIndex;
InitializedEntity MemberEntity =
InitializedEntity::InitializeMember(*Field, &Entity);
if (CheckDesignatedInitializer(MemberEntity, IList, DIE, DesigIdx + 1,
FieldType, nullptr, nullptr, Index,
StructuredList, newStructuredIndex,
FinishSubobjectInit, false))
return true;
}
// Find the position of the next field to be initialized in this
// subobject.
++Field;
++FieldIndex;
// If this the first designator, our caller will continue checking
// the rest of this struct/class/union subobject.
if (IsFirstDesignator) {
if (NextField)
*NextField = Field;
StructuredIndex = FieldIndex;
return false;
}
if (!FinishSubobjectInit)
return false;
// We've already initialized something in the union; we're done.
if (RT->getDecl()->isUnion())
return hadError;
// Check the remaining fields within this class/struct/union subobject.
bool prevHadError = hadError;
auto NoBases =
CXXRecordDecl::base_class_range(CXXRecordDecl::base_class_iterator(),
CXXRecordDecl::base_class_iterator());
CheckStructUnionTypes(Entity, IList, CurrentObjectType, NoBases, Field,
false, Index, StructuredList, FieldIndex);
return hadError && !prevHadError;
}
// C99 6.7.8p6:
//
// If a designator has the form
//
// [ constant-expression ]
//
// then the current object (defined below) shall have array
// type and the expression shall be an integer constant
// expression. If the array is of unknown size, any
// nonnegative value is valid.
//
// Additionally, cope with the GNU extension that permits
// designators of the form
//
// [ constant-expression ... constant-expression ]
const ArrayType *AT = SemaRef.Context.getAsArrayType(CurrentObjectType);
if (!AT) {
if (!VerifyOnly)
SemaRef.Diag(D->getLBracketLoc(), diag::err_array_designator_non_array)
<< CurrentObjectType;
++Index;
return true;
}
Expr *IndexExpr = nullptr;
llvm::APSInt DesignatedStartIndex, DesignatedEndIndex;
if (D->isArrayDesignator()) {
IndexExpr = DIE->getArrayIndex(*D);
DesignatedStartIndex = IndexExpr->EvaluateKnownConstInt(SemaRef.Context);
DesignatedEndIndex = DesignatedStartIndex;
} else {
assert(D->isArrayRangeDesignator() && "Need array-range designator");
DesignatedStartIndex =
DIE->getArrayRangeStart(*D)->EvaluateKnownConstInt(SemaRef.Context);
DesignatedEndIndex =
DIE->getArrayRangeEnd(*D)->EvaluateKnownConstInt(SemaRef.Context);
IndexExpr = DIE->getArrayRangeEnd(*D);
// Codegen can't handle evaluating array range designators that have side
// effects, because we replicate the AST value for each initialized element.
// As such, set the sawArrayRangeDesignator() bit if we initialize multiple
// elements with something that has a side effect, so codegen can emit an
// "error unsupported" error instead of miscompiling the app.
if (DesignatedStartIndex.getZExtValue()!=DesignatedEndIndex.getZExtValue()&&
DIE->getInit()->HasSideEffects(SemaRef.Context) && !VerifyOnly)
FullyStructuredList->sawArrayRangeDesignator();
}
if (isa<ConstantArrayType>(AT)) {
llvm::APSInt MaxElements(cast<ConstantArrayType>(AT)->getSize(), false);
DesignatedStartIndex
= DesignatedStartIndex.extOrTrunc(MaxElements.getBitWidth());
DesignatedStartIndex.setIsUnsigned(MaxElements.isUnsigned());
DesignatedEndIndex
= DesignatedEndIndex.extOrTrunc(MaxElements.getBitWidth());
DesignatedEndIndex.setIsUnsigned(MaxElements.isUnsigned());
if (DesignatedEndIndex >= MaxElements) {
if (!VerifyOnly)
SemaRef.Diag(IndexExpr->getBeginLoc(),
diag::err_array_designator_too_large)
<< DesignatedEndIndex.toString(10) << MaxElements.toString(10)
<< IndexExpr->getSourceRange();
++Index;
return true;
}
} else {
unsigned DesignatedIndexBitWidth =
ConstantArrayType::getMaxSizeBits(SemaRef.Context);
DesignatedStartIndex =
DesignatedStartIndex.extOrTrunc(DesignatedIndexBitWidth);
DesignatedEndIndex =
DesignatedEndIndex.extOrTrunc(DesignatedIndexBitWidth);
DesignatedStartIndex.setIsUnsigned(true);
DesignatedEndIndex.setIsUnsigned(true);
}
bool IsStringLiteralInitUpdate =
StructuredList && StructuredList->isStringLiteralInit();
if (IsStringLiteralInitUpdate && VerifyOnly) {
// We're just verifying an update to a string literal init. We don't need
// to split the string up into individual characters to do that.
StructuredList = nullptr;
} else if (IsStringLiteralInitUpdate) {
// We're modifying a string literal init; we have to decompose the string
// so we can modify the individual characters.
ASTContext &Context = SemaRef.Context;
Expr *SubExpr = StructuredList->getInit(0)->IgnoreParens();
// Compute the character type
QualType CharTy = AT->getElementType();
// Compute the type of the integer literals.
QualType PromotedCharTy = CharTy;
if (CharTy->isPromotableIntegerType())
PromotedCharTy = Context.getPromotedIntegerType(CharTy);
unsigned PromotedCharTyWidth = Context.getTypeSize(PromotedCharTy);
if (StringLiteral *SL = dyn_cast<StringLiteral>(SubExpr)) {
// Get the length of the string.
uint64_t StrLen = SL->getLength();
if (cast<ConstantArrayType>(AT)->getSize().ult(StrLen))
StrLen = cast<ConstantArrayType>(AT)->getSize().getZExtValue();
StructuredList->resizeInits(Context, StrLen);
// Build a literal for each character in the string, and put them into
// the init list.
for (unsigned i = 0, e = StrLen; i != e; ++i) {
llvm::APInt CodeUnit(PromotedCharTyWidth, SL->getCodeUnit(i));
Expr *Init = new (Context) IntegerLiteral(
Context, CodeUnit, PromotedCharTy, SubExpr->getExprLoc());
if (CharTy != PromotedCharTy)
Init =
ImplicitCastExpr::Create(Context, CharTy, CK_IntegralCast, Init,
nullptr, VK_RValue, FPOptionsOverride());
StructuredList->updateInit(Context, i, Init);
}
} else {
ObjCEncodeExpr *E = cast<ObjCEncodeExpr>(SubExpr);
std::string Str;
Context.getObjCEncodingForType(E->getEncodedType(), Str);
// Get the length of the string.
uint64_t StrLen = Str.size();
if (cast<ConstantArrayType>(AT)->getSize().ult(StrLen))
StrLen = cast<ConstantArrayType>(AT)->getSize().getZExtValue();
StructuredList->resizeInits(Context, StrLen);
// Build a literal for each character in the string, and put them into
// the init list.
for (unsigned i = 0, e = StrLen; i != e; ++i) {
llvm::APInt CodeUnit(PromotedCharTyWidth, Str[i]);
Expr *Init = new (Context) IntegerLiteral(
Context, CodeUnit, PromotedCharTy, SubExpr->getExprLoc());
if (CharTy != PromotedCharTy)
Init =
ImplicitCastExpr::Create(Context, CharTy, CK_IntegralCast, Init,
nullptr, VK_RValue, FPOptionsOverride());
StructuredList->updateInit(Context, i, Init);
}
}
}
// Make sure that our non-designated initializer list has space
// for a subobject corresponding to this array element.
if (StructuredList &&
DesignatedEndIndex.getZExtValue() >= StructuredList->getNumInits())
StructuredList->resizeInits(SemaRef.Context,
DesignatedEndIndex.getZExtValue() + 1);
// Repeatedly perform subobject initializations in the range
// [DesignatedStartIndex, DesignatedEndIndex].
// Move to the next designator
unsigned ElementIndex = DesignatedStartIndex.getZExtValue();
unsigned OldIndex = Index;
InitializedEntity ElementEntity =
InitializedEntity::InitializeElement(SemaRef.Context, 0, Entity);
while (DesignatedStartIndex <= DesignatedEndIndex) {
// Recurse to check later designated subobjects.
QualType ElementType = AT->getElementType();
Index = OldIndex;
ElementEntity.setElementIndex(ElementIndex);
if (CheckDesignatedInitializer(
ElementEntity, IList, DIE, DesigIdx + 1, ElementType, nullptr,
nullptr, Index, StructuredList, ElementIndex,
FinishSubobjectInit && (DesignatedStartIndex == DesignatedEndIndex),
false))
return true;
// Move to the next index in the array that we'll be initializing.
++DesignatedStartIndex;
ElementIndex = DesignatedStartIndex.getZExtValue();
}
// If this the first designator, our caller will continue checking
// the rest of this array subobject.
if (IsFirstDesignator) {
if (NextElementIndex)
*NextElementIndex = DesignatedStartIndex;
StructuredIndex = ElementIndex;
return false;
}
if (!FinishSubobjectInit)
return false;
// Check the remaining elements within this array subobject.
bool prevHadError = hadError;
CheckArrayType(Entity, IList, CurrentObjectType, DesignatedStartIndex,
/*SubobjectIsDesignatorContext=*/false, Index,
StructuredList, ElementIndex);
return hadError && !prevHadError;
}
// Get the structured initializer list for a subobject of type
// @p CurrentObjectType.
InitListExpr *
InitListChecker::getStructuredSubobjectInit(InitListExpr *IList, unsigned Index,
QualType CurrentObjectType,
InitListExpr *StructuredList,
unsigned StructuredIndex,
SourceRange InitRange,
bool IsFullyOverwritten) {
if (!StructuredList)
return nullptr;
Expr *ExistingInit = nullptr;
if (StructuredIndex < StructuredList->getNumInits())
ExistingInit = StructuredList->getInit(StructuredIndex);
if (InitListExpr *Result = dyn_cast_or_null<InitListExpr>(ExistingInit))
// There might have already been initializers for subobjects of the current
// object, but a subsequent initializer list will overwrite the entirety
// of the current object. (See DR 253 and C99 6.7.8p21). e.g.,
//
// struct P { char x[6]; };
// struct P l = { .x[2] = 'x', .x = { [0] = 'f' } };
//
// The first designated initializer is ignored, and l.x is just "f".
if (!IsFullyOverwritten)
return Result;
if (ExistingInit) {
// We are creating an initializer list that initializes the
// subobjects of the current object, but there was already an
// initialization that completely initialized the current
// subobject:
//
// struct X { int a, b; };
// struct X xs[] = { [0] = { 1, 2 }, [0].b = 3 };
//
// Here, xs[0].a == 1 and xs[0].b == 3, since the second,
// designated initializer overwrites the [0].b initializer
// from the prior initialization.
//
// When the existing initializer is an expression rather than an
// initializer list, we cannot decompose and update it in this way.
// For example:
//
// struct X xs[] = { [0] = (struct X) { 1, 2 }, [0].b = 3 };
//
// This case is handled by CheckDesignatedInitializer.
diagnoseInitOverride(ExistingInit, InitRange);
}
unsigned ExpectedNumInits = 0;
if (Index < IList->getNumInits()) {
if (auto *Init = dyn_cast_or_null<InitListExpr>(IList->getInit(Index)))
ExpectedNumInits = Init->getNumInits();
else
ExpectedNumInits = IList->getNumInits() - Index;
}
InitListExpr *Result =
createInitListExpr(CurrentObjectType, InitRange, ExpectedNumInits);
// Link this new initializer list into the structured initializer
// lists.
StructuredList->updateInit(SemaRef.Context, StructuredIndex, Result);
return Result;
}
InitListExpr *
InitListChecker::createInitListExpr(QualType CurrentObjectType,
SourceRange InitRange,
unsigned ExpectedNumInits) {
InitListExpr *Result
= new (SemaRef.Context) InitListExpr(SemaRef.Context,
InitRange.getBegin(), None,
InitRange.getEnd());
QualType ResultType = CurrentObjectType;
if (!ResultType->isArrayType())
ResultType = ResultType.getNonLValueExprType(SemaRef.Context);
Result->setType(ResultType);
// Pre-allocate storage for the structured initializer list.
unsigned NumElements = 0;
if (const ArrayType *AType
= SemaRef.Context.getAsArrayType(CurrentObjectType)) {
if (const ConstantArrayType *CAType = dyn_cast<ConstantArrayType>(AType)) {
NumElements = CAType->getSize().getZExtValue();
// Simple heuristic so that we don't allocate a very large
// initializer with many empty entries at the end.
if (NumElements > ExpectedNumInits)
NumElements = 0;
}
} else if (const VectorType *VType = CurrentObjectType->getAs<VectorType>()) {
NumElements = VType->getNumElements();
} else if (CurrentObjectType->isRecordType()) {
NumElements = numStructUnionElements(CurrentObjectType);
}
Result->reserveInits(SemaRef.Context, NumElements);
return Result;
}
/// Update the initializer at index @p StructuredIndex within the
/// structured initializer list to the value @p expr.
void InitListChecker::UpdateStructuredListElement(InitListExpr *StructuredList,
unsigned &StructuredIndex,
Expr *expr) {
// No structured initializer list to update
if (!StructuredList)
return;
if (Expr *PrevInit = StructuredList->updateInit(SemaRef.Context,
StructuredIndex, expr)) {
// This initializer overwrites a previous initializer.
// No need to diagnose when `expr` is nullptr because a more relevant
// diagnostic has already been issued and this diagnostic is potentially
// noise.
if (expr)
diagnoseInitOverride(PrevInit, expr->getSourceRange());
}
++StructuredIndex;
}
/// Determine whether we can perform aggregate initialization for the purposes
/// of overload resolution.
bool Sema::CanPerformAggregateInitializationForOverloadResolution(
const InitializedEntity &Entity, InitListExpr *From) {
QualType Type = Entity.getType();
InitListChecker Check(*this, Entity, From, Type, /*VerifyOnly=*/true,
/*TreatUnavailableAsInvalid=*/false,
/*InOverloadResolution=*/true);
return !Check.HadError();
}
/// Check that the given Index expression is a valid array designator
/// value. This is essentially just a wrapper around
/// VerifyIntegerConstantExpression that also checks for negative values
/// and produces a reasonable diagnostic if there is a
/// failure. Returns the index expression, possibly with an implicit cast
/// added, on success. If everything went okay, Value will receive the
/// value of the constant expression.
static ExprResult
CheckArrayDesignatorExpr(Sema &S, Expr *Index, llvm::APSInt &Value) {
SourceLocation Loc = Index->getBeginLoc();
// Make sure this is an integer constant expression.
ExprResult Result =
S.VerifyIntegerConstantExpression(Index, &Value, Sema::AllowFold);
if (Result.isInvalid())
return Result;
if (Value.isSigned() && Value.isNegative())
return S.Diag(Loc, diag::err_array_designator_negative)
<< Value.toString(10) << Index->getSourceRange();
Value.setIsUnsigned(true);
return Result;
}
ExprResult Sema::ActOnDesignatedInitializer(Designation &Desig,
SourceLocation EqualOrColonLoc,
bool GNUSyntax,
ExprResult Init) {
typedef DesignatedInitExpr::Designator ASTDesignator;
bool Invalid = false;
SmallVector<ASTDesignator, 32> Designators;
SmallVector<Expr *, 32> InitExpressions;
// Build designators and check array designator expressions.
for (unsigned Idx = 0; Idx < Desig.getNumDesignators(); ++Idx) {
const Designator &D = Desig.getDesignator(Idx);
switch (D.getKind()) {
case Designator::FieldDesignator:
Designators.push_back(ASTDesignator(D.getField(), D.getDotLoc(),
D.getFieldLoc()));
break;
case Designator::ArrayDesignator: {
Expr *Index = static_cast<Expr *>(D.getArrayIndex());
llvm::APSInt IndexValue;
if (!Index->isTypeDependent() && !Index->isValueDependent())
Index = CheckArrayDesignatorExpr(*this, Index, IndexValue).get();
if (!Index)
Invalid = true;
else {
Designators.push_back(ASTDesignator(InitExpressions.size(),
D.getLBracketLoc(),
D.getRBracketLoc()));
InitExpressions.push_back(Index);
}
break;
}
case Designator::ArrayRangeDesignator: {
Expr *StartIndex = static_cast<Expr *>(D.getArrayRangeStart());
Expr *EndIndex = static_cast<Expr *>(D.getArrayRangeEnd());
llvm::APSInt StartValue;
llvm::APSInt EndValue;
bool StartDependent = StartIndex->isTypeDependent() ||
StartIndex->isValueDependent();
bool EndDependent = EndIndex->isTypeDependent() ||
EndIndex->isValueDependent();
if (!StartDependent)
StartIndex =
CheckArrayDesignatorExpr(*this, StartIndex, StartValue).get();
if (!EndDependent)
EndIndex = CheckArrayDesignatorExpr(*this, EndIndex, EndValue).get();
if (!StartIndex || !EndIndex)
Invalid = true;
else {
// Make sure we're comparing values with the same bit width.
if (StartDependent || EndDependent) {
// Nothing to compute.
} else if (StartValue.getBitWidth() > EndValue.getBitWidth())
EndValue = EndValue.extend(StartValue.getBitWidth());
else if (StartValue.getBitWidth() < EndValue.getBitWidth())
StartValue = StartValue.extend(EndValue.getBitWidth());
if (!StartDependent && !EndDependent && EndValue < StartValue) {
Diag(D.getEllipsisLoc(), diag::err_array_designator_empty_range)
<< StartValue.toString(10) << EndValue.toString(10)
<< StartIndex->getSourceRange() << EndIndex->getSourceRange();
Invalid = true;
} else {
Designators.push_back(ASTDesignator(InitExpressions.size(),
D.getLBracketLoc(),
D.getEllipsisLoc(),
D.getRBracketLoc()));
InitExpressions.push_back(StartIndex);
InitExpressions.push_back(EndIndex);
}
}
break;
}
}
}
if (Invalid || Init.isInvalid())
return ExprError();
// Clear out the expressions within the designation.
Desig.ClearExprs(*this);
return DesignatedInitExpr::Create(Context, Designators, InitExpressions,
EqualOrColonLoc, GNUSyntax,
Init.getAs<Expr>());
}
//===----------------------------------------------------------------------===//
// Initialization entity
//===----------------------------------------------------------------------===//
InitializedEntity::InitializedEntity(ASTContext &Context, unsigned Index,
const InitializedEntity &Parent)
: Parent(&Parent), Index(Index)
{
if (const ArrayType *AT = Context.getAsArrayType(Parent.getType())) {
Kind = EK_ArrayElement;
Type = AT->getElementType();
} else if (const VectorType *VT = Parent.getType()->getAs<VectorType>()) {
Kind = EK_VectorElement;
Type = VT->getElementType();
} else {
const ComplexType *CT = Parent.getType()->getAs<ComplexType>();
assert(CT && "Unexpected type");
Kind = EK_ComplexElement;
Type = CT->getElementType();
}
}
InitializedEntity
InitializedEntity::InitializeBase(ASTContext &Context,
const CXXBaseSpecifier *Base,
bool IsInheritedVirtualBase,
const InitializedEntity *Parent) {
InitializedEntity Result;
Result.Kind = EK_Base;
Result.Parent = Parent;
Result.Base = reinterpret_cast<uintptr_t>(Base);
if (IsInheritedVirtualBase)
Result.Base |= 0x01;
Result.Type = Base->getType();
return Result;
}
DeclarationName InitializedEntity::getName() const {
switch (getKind()) {
case EK_Parameter:
case EK_Parameter_CF_Audited: {
ParmVarDecl *D = reinterpret_cast<ParmVarDecl*>(Parameter & ~0x1);
return (D ? D->getDeclName() : DeclarationName());
}
case EK_Variable:
case EK_Member:
case EK_Binding:
case EK_TemplateParameter:
return Variable.VariableOrMember->getDeclName();
case EK_LambdaCapture:
return DeclarationName(Capture.VarID);
case EK_Result:
case EK_StmtExprResult:
case EK_Exception:
case EK_New:
case EK_Temporary:
case EK_Base:
case EK_Delegating:
case EK_ArrayElement:
case EK_VectorElement:
case EK_ComplexElement:
case EK_BlockElement:
case EK_LambdaToBlockConversionBlockElement:
case EK_CompoundLiteralInit:
case EK_RelatedResult:
return DeclarationName();
}
llvm_unreachable("Invalid EntityKind!");
}
ValueDecl *InitializedEntity::getDecl() const {
switch (getKind()) {
case EK_Variable:
case EK_Member:
case EK_Binding:
case EK_TemplateParameter:
return Variable.VariableOrMember;
case EK_Parameter:
case EK_Parameter_CF_Audited:
return reinterpret_cast<ParmVarDecl*>(Parameter & ~0x1);
case EK_Result:
case EK_StmtExprResult:
case EK_Exception:
case EK_New:
case EK_Temporary:
case EK_Base:
case EK_Delegating:
case EK_ArrayElement:
case EK_VectorElement:
case EK_ComplexElement:
case EK_BlockElement:
case EK_LambdaToBlockConversionBlockElement:
case EK_LambdaCapture:
case EK_CompoundLiteralInit:
case EK_RelatedResult:
return nullptr;
}
llvm_unreachable("Invalid EntityKind!");
}
bool InitializedEntity::allowsNRVO() const {
switch (getKind()) {
case EK_Result:
case EK_Exception:
return LocAndNRVO.NRVO;
case EK_StmtExprResult:
case EK_Variable:
case EK_Parameter:
case EK_Parameter_CF_Audited:
case EK_TemplateParameter:
case EK_Member:
case EK_Binding:
case EK_New:
case EK_Temporary:
case EK_CompoundLiteralInit:
case EK_Base:
case EK_Delegating:
case EK_ArrayElement:
case EK_VectorElement:
case EK_ComplexElement:
case EK_BlockElement:
case EK_LambdaToBlockConversionBlockElement:
case EK_LambdaCapture:
case EK_RelatedResult:
break;
}
return false;
}
unsigned InitializedEntity::dumpImpl(raw_ostream &OS) const {
assert(getParent() != this);
unsigned Depth = getParent() ? getParent()->dumpImpl(OS) : 0;
for (unsigned I = 0; I != Depth; ++I)
OS << "`-";
switch (getKind()) {
case EK_Variable: OS << "Variable"; break;
case EK_Parameter: OS << "Parameter"; break;
case EK_Parameter_CF_Audited: OS << "CF audited function Parameter";
break;
case EK_TemplateParameter: OS << "TemplateParameter"; break;
case EK_Result: OS << "Result"; break;
case EK_StmtExprResult: OS << "StmtExprResult"; break;
case EK_Exception: OS << "Exception"; break;
case EK_Member: OS << "Member"; break;
case EK_Binding: OS << "Binding"; break;
case EK_New: OS << "New"; break;
case EK_Temporary: OS << "Temporary"; break;
case EK_CompoundLiteralInit: OS << "CompoundLiteral";break;
case EK_RelatedResult: OS << "RelatedResult"; break;
case EK_Base: OS << "Base"; break;
case EK_Delegating: OS << "Delegating"; break;
case EK_ArrayElement: OS << "ArrayElement " << Index; break;
case EK_VectorElement: OS << "VectorElement " << Index; break;
case EK_ComplexElement: OS << "ComplexElement " << Index; break;
case EK_BlockElement: OS << "Block"; break;
case EK_LambdaToBlockConversionBlockElement:
OS << "Block (lambda)";
break;
case EK_LambdaCapture:
OS << "LambdaCapture ";
OS << DeclarationName(Capture.VarID);
break;
}
if (auto *D = getDecl()) {
OS << " ";
D->printQualifiedName(OS);
}
OS << " '" << getType().getAsString() << "'\n";
return Depth + 1;
}
LLVM_DUMP_METHOD void InitializedEntity::dump() const {
dumpImpl(llvm::errs());
}
//===----------------------------------------------------------------------===//
// Initialization sequence
//===----------------------------------------------------------------------===//
void InitializationSequence::Step::Destroy() {
switch (Kind) {
case SK_ResolveAddressOfOverloadedFunction:
case SK_CastDerivedToBaseRValue:
case SK_CastDerivedToBaseXValue:
case SK_CastDerivedToBaseLValue:
case SK_BindReference:
case SK_BindReferenceToTemporary:
case SK_FinalCopy:
case SK_ExtraneousCopyToTemporary:
case SK_UserConversion:
case SK_QualificationConversionRValue:
case SK_QualificationConversionXValue:
case SK_QualificationConversionLValue:
case SK_FunctionReferenceConversion:
case SK_AtomicConversion:
case SK_ListInitialization:
case SK_UnwrapInitList:
case SK_RewrapInitList:
case SK_ConstructorInitialization:
case SK_ConstructorInitializationFromList:
case SK_ZeroInitialization:
case SK_CAssignment:
case SK_StringInit:
case SK_ObjCObjectConversion:
case SK_ArrayLoopIndex:
case SK_ArrayLoopInit:
case SK_ArrayInit:
case SK_GNUArrayInit:
case SK_ParenthesizedArrayInit:
case SK_PassByIndirectCopyRestore:
case SK_PassByIndirectRestore:
case SK_ProduceObjCObject:
case SK_StdInitializerList:
case SK_StdInitializerListConstructorCall:
case SK_OCLSamplerInit:
case SK_OCLZeroOpaqueType:
break;
case SK_ConversionSequence:
case SK_ConversionSequenceNoNarrowing:
delete ICS;
}
}
bool InitializationSequence::isDirectReferenceBinding() const {
// There can be some lvalue adjustments after the SK_BindReference step.
for (auto I = Steps.rbegin(); I != Steps.rend(); ++I) {
if (I->Kind == SK_BindReference)
return true;
if (I->Kind == SK_BindReferenceToTemporary)
return false;
}
return false;
}
bool InitializationSequence::isAmbiguous() const {
if (!Failed())
return false;
switch (getFailureKind()) {
case FK_TooManyInitsForReference:
case FK_ParenthesizedListInitForReference:
case FK_ArrayNeedsInitList:
case FK_ArrayNeedsInitListOrStringLiteral:
case FK_ArrayNeedsInitListOrWideStringLiteral:
case FK_NarrowStringIntoWideCharArray:
case FK_WideStringIntoCharArray:
case FK_IncompatWideStringIntoWideChar:
case FK_PlainStringIntoUTF8Char:
case FK_UTF8StringIntoPlainChar:
case FK_AddressOfOverloadFailed: // FIXME: Could do better
case FK_NonConstLValueReferenceBindingToTemporary:
case FK_NonConstLValueReferenceBindingToBitfield:
case FK_NonConstLValueReferenceBindingToVectorElement:
case FK_NonConstLValueReferenceBindingToMatrixElement:
case FK_NonConstLValueReferenceBindingToUnrelated:
case FK_RValueReferenceBindingToLValue:
case FK_ReferenceAddrspaceMismatchTemporary:
case FK_ReferenceInitDropsQualifiers:
case FK_ReferenceInitFailed:
case FK_ConversionFailed:
case FK_ConversionFromPropertyFailed:
case FK_TooManyInitsForScalar:
case FK_ParenthesizedListInitForScalar:
case FK_ReferenceBindingToInitList:
case FK_InitListBadDestinationType:
case FK_DefaultInitOfConst:
case FK_Incomplete:
case FK_ArrayTypeMismatch:
case FK_NonConstantArrayInit:
case FK_ListInitializationFailed:
case FK_VariableLengthArrayHasInitializer:
case FK_PlaceholderType:
case FK_ExplicitConstructor:
case FK_AddressOfUnaddressableFunction:
return false;
case FK_ReferenceInitOverloadFailed:
case FK_UserConversionOverloadFailed:
case FK_ConstructorOverloadFailed:
case FK_ListConstructorOverloadFailed:
return FailedOverloadResult == OR_Ambiguous;
}
llvm_unreachable("Invalid EntityKind!");
}
bool InitializationSequence::isConstructorInitialization() const {
return !Steps.empty() && Steps.back().Kind == SK_ConstructorInitialization;
}
void
InitializationSequence
::AddAddressOverloadResolutionStep(FunctionDecl *Function,
DeclAccessPair Found,
bool HadMultipleCandidates) {
Step S;
S.Kind = SK_ResolveAddressOfOverloadedFunction;
S.Type = Function->getType();
S.Function.HadMultipleCandidates = HadMultipleCandidates;
S.Function.Function = Function;
S.Function.FoundDecl = Found;
Steps.push_back(S);
}
void InitializationSequence::AddDerivedToBaseCastStep(QualType BaseType,
ExprValueKind VK) {
Step S;
switch (VK) {
case VK_RValue: S.Kind = SK_CastDerivedToBaseRValue; break;
case VK_XValue: S.Kind = SK_CastDerivedToBaseXValue; break;
case VK_LValue: S.Kind = SK_CastDerivedToBaseLValue; break;
}
S.Type = BaseType;
Steps.push_back(S);
}
void InitializationSequence::AddReferenceBindingStep(QualType T,
bool BindingTemporary) {
Step S;
S.Kind = BindingTemporary? SK_BindReferenceToTemporary : SK_BindReference;
S.Type = T;
Steps.push_back(S);
}
void InitializationSequence::AddFinalCopy(QualType T) {
Step S;
S.Kind = SK_FinalCopy;
S.Type = T;
Steps.push_back(S);
}
void InitializationSequence::AddExtraneousCopyToTemporary(QualType T) {
Step S;
S.Kind = SK_ExtraneousCopyToTemporary;
S.Type = T;
Steps.push_back(S);
}
void
InitializationSequence::AddUserConversionStep(FunctionDecl *Function,
DeclAccessPair FoundDecl,
QualType T,
bool HadMultipleCandidates) {
Step S;
S.Kind = SK_UserConversion;
S.Type = T;
S.Function.HadMultipleCandidates = HadMultipleCandidates;
S.Function.Function = Function;
S.Function.FoundDecl = FoundDecl;
Steps.push_back(S);
}
void InitializationSequence::AddQualificationConversionStep(QualType Ty,
ExprValueKind VK) {
Step S;
S.Kind = SK_QualificationConversionRValue; // work around a gcc warning
switch (VK) {
case VK_RValue:
S.Kind = SK_QualificationConversionRValue;
break;
case VK_XValue:
S.Kind = SK_QualificationConversionXValue;
break;
case VK_LValue:
S.Kind = SK_QualificationConversionLValue;
break;
}
S.Type = Ty;
Steps.push_back(S);
}
void InitializationSequence::AddFunctionReferenceConversionStep(QualType Ty) {
Step S;
S.Kind = SK_FunctionReferenceConversion;
S.Type = Ty;
Steps.push_back(S);
}
void InitializationSequence::AddAtomicConversionStep(QualType Ty) {
Step S;
S.Kind = SK_AtomicConversion;
S.Type = Ty;
Steps.push_back(S);
}
void InitializationSequence::AddConversionSequenceStep(
const ImplicitConversionSequence &ICS, QualType T,
bool TopLevelOfInitList) {
Step S;
S.Kind = TopLevelOfInitList ? SK_ConversionSequenceNoNarrowing
: SK_ConversionSequence;
S.Type = T;
S.ICS = new ImplicitConversionSequence(ICS);
Steps.push_back(S);
}
void InitializationSequence::AddListInitializationStep(QualType T) {
Step S;
S.Kind = SK_ListInitialization;
S.Type = T;
Steps.push_back(S);
}
void InitializationSequence::AddConstructorInitializationStep(
DeclAccessPair FoundDecl, CXXConstructorDecl *Constructor, QualType T,
bool HadMultipleCandidates, bool FromInitList, bool AsInitList) {
Step S;
S.Kind = FromInitList ? AsInitList ? SK_StdInitializerListConstructorCall
: SK_ConstructorInitializationFromList
: SK_ConstructorInitialization;
S.Type = T;
S.Function.HadMultipleCandidates = HadMultipleCandidates;
S.Function.Function = Constructor;
S.Function.FoundDecl = FoundDecl;
Steps.push_back(S);
}
void InitializationSequence::AddZeroInitializationStep(QualType T) {
Step S;
S.Kind = SK_ZeroInitialization;
S.Type = T;
Steps.push_back(S);
}
void InitializationSequence::AddCAssignmentStep(QualType T) {
Step S;
S.Kind = SK_CAssignment;
S.Type = T;
Steps.push_back(S);
}
void InitializationSequence::AddStringInitStep(QualType T) {
Step S;
S.Kind = SK_StringInit;
S.Type = T;
Steps.push_back(S);
}
void InitializationSequence::AddObjCObjectConversionStep(QualType T) {
Step S;
S.Kind = SK_ObjCObjectConversion;
S.Type = T;
Steps.push_back(S);
}
void InitializationSequence::AddArrayInitStep(QualType T, bool IsGNUExtension) {
Step S;
S.Kind = IsGNUExtension ? SK_GNUArrayInit : SK_ArrayInit;
S.Type = T;
Steps.push_back(S);
}
void InitializationSequence::AddArrayInitLoopStep(QualType T, QualType EltT) {
Step S;
S.Kind = SK_ArrayLoopIndex;
S.Type = EltT;
Steps.insert(Steps.begin(), S);
S.Kind = SK_ArrayLoopInit;
S.Type = T;
Steps.push_back(S);
}
void InitializationSequence::AddParenthesizedArrayInitStep(QualType T) {
Step S;
S.Kind = SK_ParenthesizedArrayInit;
S.Type = T;
Steps.push_back(S);
}
void InitializationSequence::AddPassByIndirectCopyRestoreStep(QualType type,
bool shouldCopy) {
Step s;
s.Kind = (shouldCopy ? SK_PassByIndirectCopyRestore
: SK_PassByIndirectRestore);
s.Type = type;
Steps.push_back(s);
}
void InitializationSequence::AddProduceObjCObjectStep(QualType T) {
Step S;
S.Kind = SK_ProduceObjCObject;
S.Type = T;
Steps.push_back(S);
}
void InitializationSequence::AddStdInitializerListConstructionStep(QualType T) {
Step S;
S.Kind = SK_StdInitializerList;
S.Type = T;
Steps.push_back(S);
}
void InitializationSequence::AddOCLSamplerInitStep(QualType T) {
Step S;
S.Kind = SK_OCLSamplerInit;
S.Type = T;
Steps.push_back(S);
}
void InitializationSequence::AddOCLZeroOpaqueTypeStep(QualType T) {
Step S;
S.Kind = SK_OCLZeroOpaqueType;
S.Type = T;
Steps.push_back(S);
}
void InitializationSequence::RewrapReferenceInitList(QualType T,
InitListExpr *Syntactic) {
assert(Syntactic->getNumInits() == 1 &&
"Can only rewrap trivial init lists.");
Step S;
S.Kind = SK_UnwrapInitList;
S.Type = Syntactic->getInit(0)->getType();
Steps.insert(Steps.begin(), S);
S.Kind = SK_RewrapInitList;
S.Type = T;
S.WrappingSyntacticList = Syntactic;
Steps.push_back(S);
}
void InitializationSequence::SetOverloadFailure(FailureKind Failure,
OverloadingResult Result) {
setSequenceKind(FailedSequence);
this->Failure = Failure;
this->FailedOverloadResult = Result;
}
//===----------------------------------------------------------------------===//
// Attempt initialization
//===----------------------------------------------------------------------===//
/// Tries to add a zero initializer. Returns true if that worked.
static bool
maybeRecoverWithZeroInitialization(Sema &S, InitializationSequence &Sequence,
const InitializedEntity &Entity) {
if (Entity.getKind() != InitializedEntity::EK_Variable)
return false;
VarDecl *VD = cast<VarDecl>(Entity.getDecl());
if (VD->getInit() || VD->getEndLoc().isMacroID())
return false;
QualType VariableTy = VD->getType().getCanonicalType();
SourceLocation Loc = S.getLocForEndOfToken(VD->getEndLoc());
std::string Init = S.getFixItZeroInitializerForType(VariableTy, Loc);
if (!Init.empty()) {
Sequence.AddZeroInitializationStep(Entity.getType());
Sequence.SetZeroInitializationFixit(Init, Loc);
return true;
}
return false;
}
static void MaybeProduceObjCObject(Sema &S,
InitializationSequence &Sequence,
const InitializedEntity &Entity) {
if (!S.getLangOpts().ObjCAutoRefCount) return;
/// When initializing a parameter, produce the value if it's marked
/// __attribute__((ns_consumed)).
if (Entity.isParameterKind()) {
if (!Entity.isParameterConsumed())
return;
assert(Entity.getType()->isObjCRetainableType() &&
"consuming an object of unretainable type?");
Sequence.AddProduceObjCObjectStep(Entity.getType());
/// When initializing a return value, if the return type is a
/// retainable type, then returns need to immediately retain the
/// object. If an autorelease is required, it will be done at the
/// last instant.
} else if (Entity.getKind() == InitializedEntity::EK_Result ||
Entity.getKind() == InitializedEntity::EK_StmtExprResult) {
if (!Entity.getType()->isObjCRetainableType())
return;
Sequence.AddProduceObjCObjectStep(Entity.getType());
}
}
static void TryListInitialization(Sema &S,
const InitializedEntity &Entity,
const InitializationKind &Kind,
InitListExpr *InitList,
InitializationSequence &Sequence,
bool TreatUnavailableAsInvalid);
/// When initializing from init list via constructor, handle
/// initialization of an object of type std::initializer_list<T>.
///
/// \return true if we have handled initialization of an object of type
/// std::initializer_list<T>, false otherwise.
static bool TryInitializerListConstruction(Sema &S,
InitListExpr *List,
QualType DestType,
InitializationSequence &Sequence,
bool TreatUnavailableAsInvalid) {
QualType E;
if (!S.isStdInitializerList(DestType, &E))
return false;
if (!S.isCompleteType(List->getExprLoc(), E)) {
Sequence.setIncompleteTypeFailure(E);
return true;
}
// Try initializing a temporary array from the init list.
QualType ArrayType = S.Context.getConstantArrayType(
E.withConst(),
llvm::APInt(S.Context.getTypeSize(S.Context.getSizeType()),
List->getNumInits()),
nullptr, clang::ArrayType::Normal, 0);
InitializedEntity HiddenArray =
InitializedEntity::InitializeTemporary(ArrayType);
InitializationKind Kind = InitializationKind::CreateDirectList(
List->getExprLoc(), List->getBeginLoc(), List->getEndLoc());
TryListInitialization(S, HiddenArray, Kind, List, Sequence,
TreatUnavailableAsInvalid);
if (Sequence)
Sequence.AddStdInitializerListConstructionStep(DestType);
return true;
}
/// Determine if the constructor has the signature of a copy or move
/// constructor for the type T of the class in which it was found. That is,
/// determine if its first parameter is of type T or reference to (possibly
/// cv-qualified) T.
static bool hasCopyOrMoveCtorParam(ASTContext &Ctx,
const ConstructorInfo &Info) {
if (Info.Constructor->getNumParams() == 0)
return false;
QualType ParmT =
Info.Constructor->getParamDecl(0)->getType().getNonReferenceType();
QualType ClassT =
Ctx.getRecordType(cast<CXXRecordDecl>(Info.FoundDecl->getDeclContext()));
return Ctx.hasSameUnqualifiedType(ParmT, ClassT);
}
static OverloadingResult
ResolveConstructorOverload(Sema &S, SourceLocation DeclLoc,
MultiExprArg Args,
OverloadCandidateSet &CandidateSet,
QualType DestType,
DeclContext::lookup_result Ctors,
OverloadCandidateSet::iterator &Best,
bool CopyInitializing, bool AllowExplicit,
bool OnlyListConstructors, bool IsListInit,
bool SecondStepOfCopyInit = false) {
CandidateSet.clear(OverloadCandidateSet::CSK_InitByConstructor);
CandidateSet.setDestAS(DestType.getQualifiers().getAddressSpace());
for (NamedDecl *D : Ctors) {
auto Info = getConstructorInfo(D);
if (!Info.Constructor || Info.Constructor->isInvalidDecl())
continue;
if (OnlyListConstructors && !S.isInitListConstructor(Info.Constructor))
continue;
// C++11 [over.best.ics]p4:
// ... and the constructor or user-defined conversion function is a
// candidate by
// - 13.3.1.3, when the argument is the temporary in the second step
// of a class copy-initialization, or
// - 13.3.1.4, 13.3.1.5, or 13.3.1.6 (in all cases), [not handled here]
// - the second phase of 13.3.1.7 when the initializer list has exactly
// one element that is itself an initializer list, and the target is
// the first parameter of a constructor of class X, and the conversion
// is to X or reference to (possibly cv-qualified X),
// user-defined conversion sequences are not considered.
bool SuppressUserConversions =
SecondStepOfCopyInit ||
(IsListInit && Args.size() == 1 && isa<InitListExpr>(Args[0]) &&
hasCopyOrMoveCtorParam(S.Context, Info));
if (Info.ConstructorTmpl)
S.AddTemplateOverloadCandidate(
Info.ConstructorTmpl, Info.FoundDecl,
/*ExplicitArgs*/ nullptr, Args, CandidateSet, SuppressUserConversions,
/*PartialOverloading=*/false, AllowExplicit);
else {
// C++ [over.match.copy]p1:
// - When initializing a temporary to be bound to the first parameter
// of a constructor [for type T] that takes a reference to possibly
// cv-qualified T as its first argument, called with a single
// argument in the context of direct-initialization, explicit
// conversion functions are also considered.
// FIXME: What if a constructor template instantiates to such a signature?
bool AllowExplicitConv = AllowExplicit && !CopyInitializing &&
Args.size() == 1 &&
hasCopyOrMoveCtorParam(S.Context, Info);
S.AddOverloadCandidate(Info.Constructor, Info.FoundDecl, Args,
CandidateSet, SuppressUserConversions,
/*PartialOverloading=*/false, AllowExplicit,
AllowExplicitConv);
}
}
// FIXME: Work around a bug in C++17 guaranteed copy elision.
//
// When initializing an object of class type T by constructor
// ([over.match.ctor]) or by list-initialization ([over.match.list])
// from a single expression of class type U, conversion functions of
// U that convert to the non-reference type cv T are candidates.
// Explicit conversion functions are only candidates during
// direct-initialization.
//
// Note: SecondStepOfCopyInit is only ever true in this case when
// evaluating whether to produce a C++98 compatibility warning.
if (S.getLangOpts().CPlusPlus17 && Args.size() == 1 &&
!SecondStepOfCopyInit) {
Expr *Initializer = Args[0];
auto *SourceRD = Initializer->getType()->getAsCXXRecordDecl();
if (SourceRD && S.isCompleteType(DeclLoc, Initializer->getType())) {
const auto &Conversions = SourceRD->getVisibleConversionFunctions();
for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
NamedDecl *D = *I;
CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(D->getDeclContext());
D = D->getUnderlyingDecl();
FunctionTemplateDecl *ConvTemplate = dyn_cast<FunctionTemplateDecl>(D);
CXXConversionDecl *Conv;
if (ConvTemplate)
Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
else
Conv = cast<CXXConversionDecl>(D);
if (ConvTemplate)
S.AddTemplateConversionCandidate(
ConvTemplate, I.getPair(), ActingDC, Initializer, DestType,
CandidateSet, AllowExplicit, AllowExplicit,
/*AllowResultConversion*/ false);
else
S.AddConversionCandidate(Conv, I.getPair(), ActingDC, Initializer,
DestType, CandidateSet, AllowExplicit,
AllowExplicit,
/*AllowResultConversion*/ false);
}
}
}
// Perform overload resolution and return the result.
return CandidateSet.BestViableFunction(S, DeclLoc, Best);
}
/// Attempt initialization by constructor (C++ [dcl.init]), which
/// enumerates the constructors of the initialized entity and performs overload
/// resolution to select the best.
/// \param DestType The destination class type.
/// \param DestArrayType The destination type, which is either DestType or
/// a (possibly multidimensional) array of DestType.
/// \param IsListInit Is this list-initialization?
/// \param IsInitListCopy Is this non-list-initialization resulting from a
/// list-initialization from {x} where x is the same
/// type as the entity?
static void TryConstructorInitialization(Sema &S,
const InitializedEntity &Entity,
const InitializationKind &Kind,
MultiExprArg Args, QualType DestType,
QualType DestArrayType,
InitializationSequence &Sequence,
bool IsListInit = false,
bool IsInitListCopy = false) {
assert(((!IsListInit && !IsInitListCopy) ||
(Args.size() == 1 && isa<InitListExpr>(Args[0]))) &&
"IsListInit/IsInitListCopy must come with a single initializer list "
"argument.");
InitListExpr *ILE =
(IsListInit || IsInitListCopy) ? cast<InitListExpr>(Args[0]) : nullptr;
MultiExprArg UnwrappedArgs =
ILE ? MultiExprArg(ILE->getInits(), ILE->getNumInits()) : Args;
// The type we're constructing needs to be complete.
if (!S.isCompleteType(Kind.getLocation(), DestType)) {
Sequence.setIncompleteTypeFailure(DestType);
return;
}
// C++17 [dcl.init]p17:
// - If the initializer expression is a prvalue and the cv-unqualified
// version of the source type is the same class as the class of the
// destination, the initializer expression is used to initialize the
// destination object.
// Per DR (no number yet), this does not apply when initializing a base
// class or delegating to another constructor from a mem-initializer.
// ObjC++: Lambda captured by the block in the lambda to block conversion
// should avoid copy elision.
if (S.getLangOpts().CPlusPlus17 &&
Entity.getKind() != InitializedEntity::EK_Base &&
Entity.getKind() != InitializedEntity::EK_Delegating &&
Entity.getKind() !=
InitializedEntity::EK_LambdaToBlockConversionBlockElement &&
UnwrappedArgs.size() == 1 && UnwrappedArgs[0]->isRValue() &&
S.Context.hasSameUnqualifiedType(UnwrappedArgs[0]->getType(), DestType)) {
// Convert qualifications if necessary.
Sequence.AddQualificationConversionStep(DestType, VK_RValue);
if (ILE)
Sequence.RewrapReferenceInitList(DestType, ILE);
return;
}
const RecordType *DestRecordType = DestType->getAs<RecordType>();
assert(DestRecordType && "Constructor initialization requires record type");
CXXRecordDecl *DestRecordDecl
= cast<CXXRecordDecl>(DestRecordType->getDecl());
// Build the candidate set directly in the initialization sequence
// structure, so that it will persist if we fail.
OverloadCandidateSet &CandidateSet = Sequence.getFailedCandidateSet();
// Determine whether we are allowed to call explicit constructors or
// explicit conversion operators.
bool AllowExplicit = Kind.AllowExplicit() || IsListInit;
bool CopyInitialization = Kind.getKind() == InitializationKind::IK_Copy;
// - Otherwise, if T is a class type, constructors are considered. The
// applicable constructors are enumerated, and the best one is chosen
// through overload resolution.
DeclContext::lookup_result Ctors = S.LookupConstructors(DestRecordDecl);
OverloadingResult Result = OR_No_Viable_Function;
OverloadCandidateSet::iterator Best;
bool AsInitializerList = false;
// C++11 [over.match.list]p1, per DR1467:
// When objects of non-aggregate type T are list-initialized, such that
// 8.5.4 [dcl.init.list] specifies that overload resolution is performed
// according to the rules in this section, overload resolution selects
// the constructor in two phases:
//
// - Initially, the candidate functions are the initializer-list
// constructors of the class T and the argument list consists of the
// initializer list as a single argument.
if (IsListInit) {
AsInitializerList = true;
// If the initializer list has no elements and T has a default constructor,
// the first phase is omitted.
if (!(UnwrappedArgs.empty() && S.LookupDefaultConstructor(DestRecordDecl)))
Result = ResolveConstructorOverload(S, Kind.getLocation(), Args,
CandidateSet, DestType, Ctors, Best,
CopyInitialization, AllowExplicit,
/*OnlyListConstructors=*/true,
IsListInit);
}
// C++11 [over.match.list]p1:
// - If no viable initializer-list constructor is found, overload resolution
// is performed again, where the candidate functions are all the
// constructors of the class T and the argument list consists of the
// elements of the initializer list.
if (Result == OR_No_Viable_Function) {
AsInitializerList = false;
Result = ResolveConstructorOverload(S, Kind.getLocation(), UnwrappedArgs,
CandidateSet, DestType, Ctors, Best,
CopyInitialization, AllowExplicit,
/*OnlyListConstructors=*/false,
IsListInit);
}
if (Result) {
Sequence.SetOverloadFailure(
IsListInit ? InitializationSequence::FK_ListConstructorOverloadFailed
: InitializationSequence::FK_ConstructorOverloadFailed,
Result);
if (Result != OR_Deleted)
return;
}
bool HadMultipleCandidates = (CandidateSet.size() > 1);
// In C++17, ResolveConstructorOverload can select a conversion function
// instead of a constructor.
if (auto *CD = dyn_cast<CXXConversionDecl>(Best->Function)) {
// Add the user-defined conversion step that calls the conversion function.
QualType ConvType = CD->getConversionType();
assert(S.Context.hasSameUnqualifiedType(ConvType, DestType) &&
"should not have selected this conversion function");
Sequence.AddUserConversionStep(CD, Best->FoundDecl, ConvType,
HadMultipleCandidates);
if (!S.Context.hasSameType(ConvType, DestType))
Sequence.AddQualificationConversionStep(DestType, VK_RValue);
if (IsListInit)
Sequence.RewrapReferenceInitList(Entity.getType(), ILE);
return;
}
CXXConstructorDecl *CtorDecl = cast<CXXConstructorDecl>(Best->Function);
if (Result != OR_Deleted) {
// C++11 [dcl.init]p6:
// If a program calls for the default initialization of an object
// of a const-qualified type T, T shall be a class type with a
// user-provided default constructor.
// C++ core issue 253 proposal:
// If the implicit default constructor initializes all subobjects, no
// initializer should be required.
// The 253 proposal is for example needed to process libstdc++ headers
// in 5.x.
if (Kind.getKind() == InitializationKind::IK_Default &&
Entity.getType().isConstQualified()) {
if (!CtorDecl->getParent()->allowConstDefaultInit()) {
if (!maybeRecoverWithZeroInitialization(S, Sequence, Entity))
Sequence.SetFailed(InitializationSequence::FK_DefaultInitOfConst);
return;
}
}
// C++11 [over.match.list]p1:
// In copy-list-initialization, if an explicit constructor is chosen, the
// initializer is ill-formed.
if (IsListInit && !Kind.AllowExplicit() && CtorDecl->isExplicit()) {
Sequence.SetFailed(InitializationSequence::FK_ExplicitConstructor);
return;
}
}
// [class.copy.elision]p3:
// In some copy-initialization contexts, a two-stage overload resolution
// is performed.
// If the first overload resolution selects a deleted function, we also
// need the initialization sequence to decide whether to perform the second
// overload resolution.
// For deleted functions in other contexts, there is no need to get the
// initialization sequence.
if (Result == OR_Deleted && Kind.getKind() != InitializationKind::IK_Copy)
return;
// Add the constructor initialization step. Any cv-qualification conversion is
// subsumed by the initialization.
Sequence.AddConstructorInitializationStep(
Best->FoundDecl, CtorDecl, DestArrayType, HadMultipleCandidates,
IsListInit | IsInitListCopy, AsInitializerList);
}
static bool
ResolveOverloadedFunctionForReferenceBinding(Sema &S,
Expr *Initializer,
QualType &SourceType,
QualType &UnqualifiedSourceType,
QualType UnqualifiedTargetType,
InitializationSequence &Sequence) {
if (S.Context.getCanonicalType(UnqualifiedSourceType) ==
S.Context.OverloadTy) {
DeclAccessPair Found;
bool HadMultipleCandidates = false;
if (FunctionDecl *Fn
= S.ResolveAddressOfOverloadedFunction(Initializer,
UnqualifiedTargetType,
false, Found,
&HadMultipleCandidates)) {
Sequence.AddAddressOverloadResolutionStep(Fn, Found,
HadMultipleCandidates);
SourceType = Fn->getType();
UnqualifiedSourceType = SourceType.getUnqualifiedType();
} else if (!UnqualifiedTargetType->isRecordType()) {
Sequence.SetFailed(InitializationSequence::FK_AddressOfOverloadFailed);
return true;
}
}
return false;
}
static void TryReferenceInitializationCore(Sema &S,
const InitializedEntity &Entity,
const InitializationKind &Kind,
Expr *Initializer,
QualType cv1T1, QualType T1,
Qualifiers T1Quals,
QualType cv2T2, QualType T2,
Qualifiers T2Quals,
InitializationSequence &Sequence);
static void TryValueInitialization(Sema &S,
const InitializedEntity &Entity,
const InitializationKind &Kind,
InitializationSequence &Sequence,
InitListExpr *InitList = nullptr);
/// Attempt list initialization of a reference.
static void TryReferenceListInitialization(Sema &S,
const InitializedEntity &Entity,
const InitializationKind &Kind,
InitListExpr *InitList,
InitializationSequence &Sequence,
bool TreatUnavailableAsInvalid) {
// First, catch C++03 where this isn't possible.
if (!S.getLangOpts().CPlusPlus11) {
Sequence.SetFailed(InitializationSequence::FK_ReferenceBindingToInitList);
return;
}
// Can't reference initialize a compound literal.
if (Entity.getKind() == InitializedEntity::EK_CompoundLiteralInit) {
Sequence.SetFailed(InitializationSequence::FK_ReferenceBindingToInitList);
return;
}
QualType DestType = Entity.getType();
QualType cv1T1 = DestType->castAs<ReferenceType>()->getPointeeType();
Qualifiers T1Quals;
QualType T1 = S.Context.getUnqualifiedArrayType(cv1T1, T1Quals);
// Reference initialization via an initializer list works thus:
// If the initializer list consists of a single element that is
// reference-related to the referenced type, bind directly to that element
// (possibly creating temporaries).
// Otherwise, initialize a temporary with the initializer list and
// bind to that.
if (InitList->getNumInits() == 1) {
Expr *Initializer = InitList->getInit(0);
QualType cv2T2 = S.getCompletedType(Initializer);
Qualifiers T2Quals;
QualType T2 = S.Context.getUnqualifiedArrayType(cv2T2, T2Quals);
// If this fails, creating a temporary wouldn't work either.
if (ResolveOverloadedFunctionForReferenceBinding(S, Initializer, cv2T2, T2,
T1, Sequence))
return;
SourceLocation DeclLoc = Initializer->getBeginLoc();
Sema::ReferenceCompareResult RefRelationship
= S.CompareReferenceRelationship(DeclLoc, cv1T1, cv2T2);
if (RefRelationship >= Sema::Ref_Related) {
// Try to bind the reference here.
TryReferenceInitializationCore(S, Entity, Kind, Initializer, cv1T1, T1,
T1Quals, cv2T2, T2, T2Quals, Sequence);
if (Sequence)
Sequence.RewrapReferenceInitList(cv1T1, InitList);
return;
}
// Update the initializer if we've resolved an overloaded function.
if (Sequence.step_begin() != Sequence.step_end())
Sequence.RewrapReferenceInitList(cv1T1, InitList);
}
// Not reference-related. Create a temporary and bind to that.
InitializedEntity TempEntity = InitializedEntity::InitializeTemporary(cv1T1);
TryListInitialization(S, TempEntity, Kind, InitList, Sequence,
TreatUnavailableAsInvalid);
if (Sequence) {
if (DestType->isRValueReferenceType() ||
(T1Quals.hasConst() && !T1Quals.hasVolatile()))
Sequence.AddReferenceBindingStep(cv1T1, /*BindingTemporary=*/true);
else
Sequence.SetFailed(
InitializationSequence::FK_NonConstLValueReferenceBindingToTemporary);
}
}
/// Attempt list initialization (C++0x [dcl.init.list])
static void TryListInitialization(Sema &S,
const InitializedEntity &Entity,
const InitializationKind &Kind,
InitListExpr *InitList,
InitializationSequence &Sequence,
bool TreatUnavailableAsInvalid) {
QualType DestType = Entity.getType();
// C++ doesn't allow scalar initialization with more than one argument.
// But C99 complex numbers are scalars and it makes sense there.
if (S.getLangOpts().CPlusPlus && DestType->isScalarType() &&
!DestType->isAnyComplexType() && InitList->getNumInits() > 1) {
Sequence.SetFailed(InitializationSequence::FK_TooManyInitsForScalar);
return;
}
if (DestType->isReferenceType()) {
TryReferenceListInitialization(S, Entity, Kind, InitList, Sequence,
TreatUnavailableAsInvalid);
return;
}
if (DestType->isRecordType() &&
!S.isCompleteType(InitList->getBeginLoc(), DestType)) {
Sequence.setIncompleteTypeFailure(DestType);
return;
}
// C++11 [dcl.init.list]p3, per DR1467:
// - If T is a class type and the initializer list has a single element of
// type cv U, where U is T or a class derived from T, the object is
// initialized from that element (by copy-initialization for
// copy-list-initialization, or by direct-initialization for
// direct-list-initialization).
// - Otherwise, if T is a character array and the initializer list has a
// single element that is an appropriately-typed string literal
// (8.5.2 [dcl.init.string]), initialization is performed as described
// in that section.
// - Otherwise, if T is an aggregate, [...] (continue below).
if (S.getLangOpts().CPlusPlus11 && InitList->getNumInits() == 1) {
if (DestType->isRecordType()) {
QualType InitType = InitList->getInit(0)->getType();
if (S.Context.hasSameUnqualifiedType(InitType, DestType) ||
S.IsDerivedFrom(InitList->getBeginLoc(), InitType, DestType)) {
Expr *InitListAsExpr = InitList;
TryConstructorInitialization(S, Entity, Kind, InitListAsExpr, DestType,
DestType, Sequence,
/*InitListSyntax*/false,
/*IsInitListCopy*/true);
return;
}
}
if (const ArrayType *DestAT = S.Context.getAsArrayType(DestType)) {
Expr *SubInit[1] = {InitList->getInit(0)};
if (!isa<VariableArrayType>(DestAT) &&
IsStringInit(SubInit[0], DestAT, S.Context) == SIF_None) {
InitializationKind SubKind =
Kind.getKind() == InitializationKind::IK_DirectList
? InitializationKind::CreateDirect(Kind.getLocation(),
InitList->getLBraceLoc(),
InitList->getRBraceLoc())
: Kind;
Sequence.InitializeFrom(S, Entity, SubKind, SubInit,
/*TopLevelOfInitList*/ true,
TreatUnavailableAsInvalid);
// TryStringLiteralInitialization() (in InitializeFrom()) will fail if
// the element is not an appropriately-typed string literal, in which
// case we should proceed as in C++11 (below).
if (Sequence) {
Sequence.RewrapReferenceInitList(Entity.getType(), InitList);
return;
}
}
}
}
// C++11 [dcl.init.list]p3:
// - If T is an aggregate, aggregate initialization is performed.
if ((DestType->isRecordType() && !DestType->isAggregateType()) ||
(S.getLangOpts().CPlusPlus11 &&
S.isStdInitializerList(DestType, nullptr))) {
if (S.getLangOpts().CPlusPlus11) {
// - Otherwise, if the initializer list has no elements and T is a
// class type with a default constructor, the object is
// value-initialized.
if (InitList->getNumInits() == 0) {
CXXRecordDecl *RD = DestType->getAsCXXRecordDecl();
if (S.LookupDefaultConstructor(RD)) {
TryValueInitialization(S, Entity, Kind, Sequence, InitList);
return;
}
}
// - Otherwise, if T is a specialization of std::initializer_list<E>,
// an initializer_list object constructed [...]
if (TryInitializerListConstruction(S, InitList, DestType, Sequence,
TreatUnavailableAsInvalid))
return;
// - Otherwise, if T is a class type, constructors are considered.
Expr *InitListAsExpr = InitList;
TryConstructorInitialization(S, Entity, Kind, InitListAsExpr, DestType,
DestType, Sequence, /*InitListSyntax*/true);
} else
Sequence.SetFailed(InitializationSequence::FK_InitListBadDestinationType);
return;
}
if (S.getLangOpts().CPlusPlus && !DestType->isAggregateType() &&
InitList->getNumInits() == 1) {
Expr *E = InitList->getInit(0);
// - Otherwise, if T is an enumeration with a fixed underlying type,
// the initializer-list has a single element v, and the initialization
// is direct-list-initialization, the object is initialized with the
// value T(v); if a narrowing conversion is required to convert v to
// the underlying type of T, the program is ill-formed.
auto *ET = DestType->getAs<EnumType>();
if (S.getLangOpts().CPlusPlus17 &&
Kind.getKind() == InitializationKind::IK_DirectList &&
ET && ET->getDecl()->isFixed() &&
!S.Context.hasSameUnqualifiedType(E->getType(), DestType) &&
(E->getType()->isIntegralOrEnumerationType() ||
E->getType()->isFloatingType())) {
// There are two ways that T(v) can work when T is an enumeration type.
// If there is either an implicit conversion sequence from v to T or
// a conversion function that can convert from v to T, then we use that.
// Otherwise, if v is of integral, enumeration, or floating-point type,
// it is converted to the enumeration type via its underlying type.
// There is no overlap possible between these two cases (except when the
// source value is already of the destination type), and the first
// case is handled by the general case for single-element lists below.
ImplicitConversionSequence ICS;
ICS.setStandard();
ICS.Standard.setAsIdentityConversion();
if (!E->isRValue())
ICS.Standard.First = ICK_Lvalue_To_Rvalue;
// If E is of a floating-point type, then the conversion is ill-formed
// due to narrowing, but go through the motions in order to produce the
// right diagnostic.
ICS.Standard.Second = E->getType()->isFloatingType()
? ICK_Floating_Integral
: ICK_Integral_Conversion;
ICS.Standard.setFromType(E->getType());
ICS.Standard.setToType(0, E->getType());
ICS.Standard.setToType(1, DestType);
ICS.Standard.setToType(2, DestType);
Sequence.AddConversionSequenceStep(ICS, ICS.Standard.getToType(2),
/*TopLevelOfInitList*/true);
Sequence.RewrapReferenceInitList(Entity.getType(), InitList);
return;
}
// - Otherwise, if the initializer list has a single element of type E
// [...references are handled above...], the object or reference is
// initialized from that element (by copy-initialization for
// copy-list-initialization, or by direct-initialization for
// direct-list-initialization); if a narrowing conversion is required
// to convert the element to T, the program is ill-formed.
//
// Per core-24034, this is direct-initialization if we were performing
// direct-list-initialization and copy-initialization otherwise.
// We can't use InitListChecker for this, because it always performs
// copy-initialization. This only matters if we might use an 'explicit'
// conversion operator, or for the special case conversion of nullptr_t to
// bool, so we only need to handle those cases.
//
// FIXME: Why not do this in all cases?
Expr *Init = InitList->getInit(0);
if (Init->getType()->isRecordType() ||
(Init->getType()->isNullPtrType() && DestType->isBooleanType())) {
InitializationKind SubKind =
Kind.getKind() == InitializationKind::IK_DirectList
? InitializationKind::CreateDirect(Kind.getLocation(),
InitList->getLBraceLoc(),
InitList->getRBraceLoc())
: Kind;
Expr *SubInit[1] = { Init };
Sequence.InitializeFrom(S, Entity, SubKind, SubInit,
/*TopLevelOfInitList*/true,
TreatUnavailableAsInvalid);
if (Sequence)
Sequence.RewrapReferenceInitList(Entity.getType(), InitList);
return;
}
}
InitListChecker CheckInitList(S, Entity, InitList,
DestType, /*VerifyOnly=*/true, TreatUnavailableAsInvalid);
if (CheckInitList.HadError()) {
Sequence.SetFailed(InitializationSequence::FK_ListInitializationFailed);
return;
}
// Add the list initialization step with the built init list.
Sequence.AddListInitializationStep(DestType);
}
/// Try a reference initialization that involves calling a conversion
/// function.
static OverloadingResult TryRefInitWithConversionFunction(
Sema &S, const InitializedEntity &Entity, const InitializationKind &Kind,
Expr *Initializer, bool AllowRValues, bool IsLValueRef,
InitializationSequence &Sequence) {
QualType DestType = Entity.getType();
QualType cv1T1 = DestType->castAs<ReferenceType>()->getPointeeType();
QualType T1 = cv1T1.getUnqualifiedType();
QualType cv2T2 = Initializer->getType();
QualType T2 = cv2T2.getUnqualifiedType();
assert(!S.CompareReferenceRelationship(Initializer->getBeginLoc(), T1, T2) &&
"Must have incompatible references when binding via conversion");
// Build the candidate set directly in the initialization sequence
// structure, so that it will persist if we fail.
OverloadCandidateSet &CandidateSet = Sequence.getFailedCandidateSet();
CandidateSet.clear(OverloadCandidateSet::CSK_InitByUserDefinedConversion);
// Determine whether we are allowed to call explicit conversion operators.
// Note that none of [over.match.copy], [over.match.conv], nor
// [over.match.ref] permit an explicit constructor to be chosen when
// initializing a reference, not even for direct-initialization.
bool AllowExplicitCtors = false;
bool AllowExplicitConvs = Kind.allowExplicitConversionFunctionsInRefBinding();
const RecordType *T1RecordType = nullptr;
if (AllowRValues && (T1RecordType = T1->getAs<RecordType>()) &&
S.isCompleteType(Kind.getLocation(), T1)) {
// The type we're converting to is a class type. Enumerate its constructors
// to see if there is a suitable conversion.
CXXRecordDecl *T1RecordDecl = cast<CXXRecordDecl>(T1RecordType->getDecl());
for (NamedDecl *D : S.LookupConstructors(T1RecordDecl)) {
auto Info = getConstructorInfo(D);
if (!Info.Constructor)
continue;
if (!Info.Constructor->isInvalidDecl() &&
Info.Constructor->isConvertingConstructor(/*AllowExplicit*/true)) {
if (Info.ConstructorTmpl)
S.AddTemplateOverloadCandidate(
Info.ConstructorTmpl, Info.FoundDecl,
/*ExplicitArgs*/ nullptr, Initializer, CandidateSet,
/*SuppressUserConversions=*/true,
/*PartialOverloading*/ false, AllowExplicitCtors);
else
S.AddOverloadCandidate(
Info.Constructor, Info.FoundDecl, Initializer, CandidateSet,
/*SuppressUserConversions=*/true,
/*PartialOverloading*/ false, AllowExplicitCtors);
}
}
}
if (T1RecordType && T1RecordType->getDecl()->isInvalidDecl())
return OR_No_Viable_Function;
const RecordType *T2RecordType = nullptr;
if ((T2RecordType = T2->getAs<RecordType>()) &&
S.isCompleteType(Kind.getLocation(), T2)) {
// The type we're converting from is a class type, enumerate its conversion
// functions.
CXXRecordDecl *T2RecordDecl = cast<CXXRecordDecl>(T2RecordType->getDecl());
const auto &Conversions = T2RecordDecl->getVisibleConversionFunctions();
for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
NamedDecl *D = *I;
CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(D->getDeclContext());
if (isa<UsingShadowDecl>(D))
D = cast<UsingShadowDecl>(D)->getTargetDecl();
FunctionTemplateDecl *ConvTemplate = dyn_cast<FunctionTemplateDecl>(D);
CXXConversionDecl *Conv;
if (ConvTemplate)
Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
else
Conv = cast<CXXConversionDecl>(D);
// If the conversion function doesn't return a reference type,
// it can't be considered for this conversion unless we're allowed to
// consider rvalues.
// FIXME: Do we need to make sure that we only consider conversion
// candidates with reference-compatible results? That might be needed to
// break recursion.
if ((AllowRValues ||
Conv->getConversionType()->isLValueReferenceType())) {
if (ConvTemplate)
S.AddTemplateConversionCandidate(
ConvTemplate, I.getPair(), ActingDC, Initializer, DestType,
CandidateSet,
/*AllowObjCConversionOnExplicit=*/false, AllowExplicitConvs);
else
S.AddConversionCandidate(
Conv, I.getPair(), ActingDC, Initializer, DestType, CandidateSet,
/*AllowObjCConversionOnExplicit=*/false, AllowExplicitConvs);
}
}
}
if (T2RecordType && T2RecordType->getDecl()->isInvalidDecl())
return OR_No_Viable_Function;
SourceLocation DeclLoc = Initializer->getBeginLoc();
// Perform overload resolution. If it fails, return the failed result.
OverloadCandidateSet::iterator Best;
if (OverloadingResult Result
= CandidateSet.BestViableFunction(S, DeclLoc, Best))
return Result;
FunctionDecl *Function = Best->Function;
// This is the overload that will be used for this initialization step if we
// use this initialization. Mark it as referenced.
Function->setReferenced();
// Compute the returned type and value kind of the conversion.
QualType cv3T3;
if (isa<CXXConversionDecl>(Function))
cv3T3 = Function->getReturnType();
else
cv3T3 = T1;
ExprValueKind VK = VK_RValue;
if (cv3T3->isLValueReferenceType())
VK = VK_LValue;
else if (const auto *RRef = cv3T3->getAs<RValueReferenceType>())
VK = RRef->getPointeeType()->isFunctionType() ? VK_LValue : VK_XValue;
cv3T3 = cv3T3.getNonLValueExprType(S.Context);
// Add the user-defined conversion step.
bool HadMultipleCandidates = (CandidateSet.size() > 1);
Sequence.AddUserConversionStep(Function, Best->FoundDecl, cv3T3,
HadMultipleCandidates);
// Determine whether we'll need to perform derived-to-base adjustments or
// other conversions.
Sema::ReferenceConversions RefConv;
Sema::ReferenceCompareResult NewRefRelationship =
S.CompareReferenceRelationship(DeclLoc, T1, cv3T3, &RefConv);
// Add the final conversion sequence, if necessary.
if (NewRefRelationship == Sema::Ref_Incompatible) {
assert(!isa<CXXConstructorDecl>(Function) &&
"should not have conversion after constructor");
ImplicitConversionSequence ICS;
ICS.setStandard();
ICS.Standard = Best->FinalConversion;
Sequence.AddConversionSequenceStep(ICS, ICS.Standard.getToType(2));
// Every implicit conversion results in a prvalue, except for a glvalue
// derived-to-base conversion, which we handle below.
cv3T3 = ICS.Standard.getToType(2);
VK = VK_RValue;
}
// If the converted initializer is a prvalue, its type T4 is adjusted to
// type "cv1 T4" and the temporary materialization conversion is applied.
//
// We adjust the cv-qualifications to match the reference regardless of
// whether we have a prvalue so that the AST records the change. In this
// case, T4 is "cv3 T3".
QualType cv1T4 = S.Context.getQualifiedType(cv3T3, cv1T1.getQualifiers());
if (cv1T4.getQualifiers() != cv3T3.getQualifiers())
Sequence.AddQualificationConversionStep(cv1T4, VK);
Sequence.AddReferenceBindingStep(cv1T4, VK == VK_RValue);
VK = IsLValueRef ? VK_LValue : VK_XValue;
if (RefConv & Sema::ReferenceConversions::DerivedToBase)
Sequence.AddDerivedToBaseCastStep(cv1T1, VK);
else if (RefConv & Sema::ReferenceConversions::ObjC)
Sequence.AddObjCObjectConversionStep(cv1T1);
else if (RefConv & Sema::ReferenceConversions::Function)
Sequence.AddFunctionReferenceConversionStep(cv1T1);
else if (RefConv & Sema::ReferenceConversions::Qualification) {
if (!S.Context.hasSameType(cv1T4, cv1T1))
Sequence.AddQualificationConversionStep(cv1T1, VK);
}
return OR_Success;
}
static void CheckCXX98CompatAccessibleCopy(Sema &S,
const InitializedEntity &Entity,
Expr *CurInitExpr);
/// Attempt reference initialization (C++0x [dcl.init.ref])
static void TryReferenceInitialization(Sema &S,
const InitializedEntity &Entity,
const InitializationKind &Kind,
Expr *Initializer,
InitializationSequence &Sequence) {
QualType DestType = Entity.getType();
QualType cv1T1 = DestType->castAs<ReferenceType>()->getPointeeType();
Qualifiers T1Quals;
QualType T1 = S.Context.getUnqualifiedArrayType(cv1T1, T1Quals);
QualType cv2T2 = S.getCompletedType(Initializer);
Qualifiers T2Quals;
QualType T2 = S.Context.getUnqualifiedArrayType(cv2T2, T2Quals);
// If the initializer is the address of an overloaded function, try
// to resolve the overloaded function. If all goes well, T2 is the
// type of the resulting function.
if (ResolveOverloadedFunctionForReferenceBinding(S, Initializer, cv2T2, T2,
T1, Sequence))
return;
// Delegate everything else to a subfunction.
TryReferenceInitializationCore(S, Entity, Kind, Initializer, cv1T1, T1,
T1Quals, cv2T2, T2, T2Quals, Sequence);
}
/// Determine whether an expression is a non-referenceable glvalue (one to
/// which a reference can never bind). Attempting to bind a reference to
/// such a glvalue will always create a temporary.
static bool isNonReferenceableGLValue(Expr *E) {
return E->refersToBitField() || E->refersToVectorElement() ||
E->refersToMatrixElement();
}
/// Reference initialization without resolving overloaded functions.
///
/// We also can get here in C if we call a builtin which is declared as
/// a function with a parameter of reference type (such as __builtin_va_end()).
static void TryReferenceInitializationCore(Sema &S,
const InitializedEntity &Entity,
const InitializationKind &Kind,
Expr *Initializer,
QualType cv1T1, QualType T1,
Qualifiers T1Quals,
QualType cv2T2, QualType T2,
Qualifiers T2Quals,
InitializationSequence &Sequence) {
QualType DestType = Entity.getType();
SourceLocation DeclLoc = Initializer->getBeginLoc();
// Compute some basic properties of the types and the initializer.
bool isLValueRef = DestType->isLValueReferenceType();
bool isRValueRef = !isLValueRef;
Expr::Classification InitCategory = Initializer->Classify(S.Context);
Sema::ReferenceConversions RefConv;
Sema::ReferenceCompareResult RefRelationship =
S.CompareReferenceRelationship(DeclLoc, cv1T1, cv2T2, &RefConv);
// C++0x [dcl.init.ref]p5:
// A reference to type "cv1 T1" is initialized by an expression of type
// "cv2 T2" as follows:
//
// - If the reference is an lvalue reference and the initializer
// expression
// Note the analogous bullet points for rvalue refs to functions. Because
// there are no function rvalues in C++, rvalue refs to functions are treated
// like lvalue refs.
OverloadingResult ConvOvlResult = OR_Success;
bool T1Function = T1->isFunctionType();
if (isLValueRef || T1Function) {
if (InitCategory.isLValue() && !isNonReferenceableGLValue(Initializer) &&
(RefRelationship == Sema::Ref_Compatible ||
(Kind.isCStyleOrFunctionalCast() &&
RefRelationship == Sema::Ref_Related))) {
// - is an lvalue (but is not a bit-field), and "cv1 T1" is
// reference-compatible with "cv2 T2," or
if (RefConv & (Sema::ReferenceConversions::DerivedToBase |
Sema::ReferenceConversions::ObjC)) {
// If we're converting the pointee, add any qualifiers first;
// these qualifiers must all be top-level, so just convert to "cv1 T2".
if (RefConv & (Sema::ReferenceConversions::Qualification))
Sequence.AddQualificationConversionStep(
S.Context.getQualifiedType(T2, T1Quals),
Initializer->getValueKind());
if (RefConv & Sema::ReferenceConversions::DerivedToBase)
Sequence.AddDerivedToBaseCastStep(cv1T1, VK_LValue);
else
Sequence.AddObjCObjectConversionStep(cv1T1);
} else if (RefConv & Sema::ReferenceConversions::Qualification) {
// Perform a (possibly multi-level) qualification conversion.
Sequence.AddQualificationConversionStep(cv1T1,
Initializer->getValueKind());
} else if (RefConv & Sema::ReferenceConversions::Function) {
Sequence.AddFunctionReferenceConversionStep(cv1T1);
}
// We only create a temporary here when binding a reference to a
// bit-field or vector element. Those cases are't supposed to be
// handled by this bullet, but the outcome is the same either way.
Sequence.AddReferenceBindingStep(cv1T1, false);
return;
}
// - has a class type (i.e., T2 is a class type), where T1 is not
// reference-related to T2, and can be implicitly converted to an
// lvalue of type "cv3 T3," where "cv1 T1" is reference-compatible
// with "cv3 T3" (this conversion is selected by enumerating the
// applicable conversion functions (13.3.1.6) and choosing the best
// one through overload resolution (13.3)),
// If we have an rvalue ref to function type here, the rhs must be
// an rvalue. DR1287 removed the "implicitly" here.
if (RefRelationship == Sema::Ref_Incompatible && T2->isRecordType() &&
(isLValueRef || InitCategory.isRValue())) {
if (S.getLangOpts().CPlusPlus) {
// Try conversion functions only for C++.
ConvOvlResult = TryRefInitWithConversionFunction(
S, Entity, Kind, Initializer, /*AllowRValues*/ isRValueRef,
/*IsLValueRef*/ isLValueRef, Sequence);
if (ConvOvlResult == OR_Success)
return;
if (ConvOvlResult != OR_No_Viable_Function)
Sequence.SetOverloadFailure(
InitializationSequence::FK_ReferenceInitOverloadFailed,
ConvOvlResult);
} else {
ConvOvlResult = OR_No_Viable_Function;
}
}
}
// - Otherwise, the reference shall be an lvalue reference to a
// non-volatile const type (i.e., cv1 shall be const), or the reference
// shall be an rvalue reference.
// For address spaces, we interpret this to mean that an addr space
// of a reference "cv1 T1" is a superset of addr space of "cv2 T2".
if (isLValueRef && !(T1Quals.hasConst() && !T1Quals.hasVolatile() &&
T1Quals.isAddressSpaceSupersetOf(T2Quals))) {
if (S.Context.getCanonicalType(T2) == S.Context.OverloadTy)
Sequence.SetFailed(InitializationSequence::FK_AddressOfOverloadFailed);
else if (ConvOvlResult && !Sequence.getFailedCandidateSet().empty())
Sequence.SetOverloadFailure(
InitializationSequence::FK_ReferenceInitOverloadFailed,
ConvOvlResult);
else if (!InitCategory.isLValue())
Sequence.SetFailed(
T1Quals.isAddressSpaceSupersetOf(T2Quals)
? InitializationSequence::
FK_NonConstLValueReferenceBindingToTemporary
: InitializationSequence::FK_ReferenceInitDropsQualifiers);
else {
InitializationSequence::FailureKind FK;
switch (RefRelationship) {
case Sema::Ref_Compatible:
if (Initializer->refersToBitField())
FK = InitializationSequence::
FK_NonConstLValueReferenceBindingToBitfield;
else if (Initializer->refersToVectorElement())
FK = InitializationSequence::
FK_NonConstLValueReferenceBindingToVectorElement;
else if (Initializer->refersToMatrixElement())
FK = InitializationSequence::
FK_NonConstLValueReferenceBindingToMatrixElement;
else
llvm_unreachable("unexpected kind of compatible initializer");
break;
case Sema::Ref_Related:
FK = InitializationSequence::FK_ReferenceInitDropsQualifiers;
break;
case Sema::Ref_Incompatible:
FK = InitializationSequence::
FK_NonConstLValueReferenceBindingToUnrelated;
break;
}
Sequence.SetFailed(FK);
}
return;
}
// - If the initializer expression
// - is an
// [<=14] xvalue (but not a bit-field), class prvalue, array prvalue, or
// [1z] rvalue (but not a bit-field) or
// function lvalue and "cv1 T1" is reference-compatible with "cv2 T2"
//
// Note: functions are handled above and below rather than here...
if (!T1Function &&
(RefRelationship == Sema::Ref_Compatible ||
(Kind.isCStyleOrFunctionalCast() &&
RefRelationship == Sema::Ref_Related)) &&
((InitCategory.isXValue() && !isNonReferenceableGLValue(Initializer)) ||
(InitCategory.isPRValue() &&
(S.getLangOpts().CPlusPlus17 || T2->isRecordType() ||
T2->isArrayType())))) {
ExprValueKind ValueKind = InitCategory.isXValue() ? VK_XValue : VK_RValue;
if (InitCategory.isPRValue() && T2->isRecordType()) {
// The corresponding bullet in C++03 [dcl.init.ref]p5 gives the
// compiler the freedom to perform a copy here or bind to the
// object, while C++0x requires that we bind directly to the
// object. Hence, we always bind to the object without making an
// extra copy. However, in C++03 requires that we check for the
// presence of a suitable copy constructor:
//
// The constructor that would be used to make the copy shall
// be callable whether or not the copy is actually done.
if (!S.getLangOpts().CPlusPlus11 && !S.getLangOpts().MicrosoftExt)
Sequence.AddExtraneousCopyToTemporary(cv2T2);
else if (S.getLangOpts().CPlusPlus11)
CheckCXX98CompatAccessibleCopy(S, Entity, Initializer);
}
// C++1z [dcl.init.ref]/5.2.1.2:
// If the converted initializer is a prvalue, its type T4 is adjusted
// to type "cv1 T4" and the temporary materialization conversion is
// applied.
// Postpone address space conversions to after the temporary materialization
// conversion to allow creating temporaries in the alloca address space.
auto T1QualsIgnoreAS = T1Quals;
auto T2QualsIgnoreAS = T2Quals;
if (T1Quals.getAddressSpace() != T2Quals.getAddressSpace()) {
T1QualsIgnoreAS.removeAddressSpace();
T2QualsIgnoreAS.removeAddressSpace();
}
QualType cv1T4 = S.Context.getQualifiedType(cv2T2, T1QualsIgnoreAS);
if (T1QualsIgnoreAS != T2QualsIgnoreAS)
Sequence.AddQualificationConversionStep(cv1T4, ValueKind);
Sequence.AddReferenceBindingStep(cv1T4, ValueKind == VK_RValue);
ValueKind = isLValueRef ? VK_LValue : VK_XValue;
// Add addr space conversion if required.
if (T1Quals.getAddressSpace() != T2Quals.getAddressSpace()) {
auto T4Quals = cv1T4.getQualifiers();
T4Quals.addAddressSpace(T1Quals.getAddressSpace());
QualType cv1T4WithAS = S.Context.getQualifiedType(T2, T4Quals);
Sequence.AddQualificationConversionStep(cv1T4WithAS, ValueKind);
cv1T4 = cv1T4WithAS;
}
// In any case, the reference is bound to the resulting glvalue (or to
// an appropriate base class subobject).
if (RefConv & Sema::ReferenceConversions::DerivedToBase)
Sequence.AddDerivedToBaseCastStep(cv1T1, ValueKind);
else if (RefConv & Sema::ReferenceConversions::ObjC)
Sequence.AddObjCObjectConversionStep(cv1T1);
else if (RefConv & Sema::ReferenceConversions::Qualification) {
if (!S.Context.hasSameType(cv1T4, cv1T1))
Sequence.AddQualificationConversionStep(cv1T1, ValueKind);
}
return;
}
// - has a class type (i.e., T2 is a class type), where T1 is not
// reference-related to T2, and can be implicitly converted to an
// xvalue, class prvalue, or function lvalue of type "cv3 T3",
// where "cv1 T1" is reference-compatible with "cv3 T3",
//
// DR1287 removes the "implicitly" here.
if (T2->isRecordType()) {
if (RefRelationship == Sema::Ref_Incompatible) {
ConvOvlResult = TryRefInitWithConversionFunction(
S, Entity, Kind, Initializer, /*AllowRValues*/ true,
/*IsLValueRef*/ isLValueRef, Sequence);
if (ConvOvlResult)
Sequence.SetOverloadFailure(
InitializationSequence::FK_ReferenceInitOverloadFailed,
ConvOvlResult);
return;
}
if (RefRelationship == Sema::Ref_Compatible &&
isRValueRef && InitCategory.isLValue()) {
Sequence.SetFailed(
InitializationSequence::FK_RValueReferenceBindingToLValue);
return;
}
Sequence.SetFailed(InitializationSequence::FK_ReferenceInitDropsQualifiers);
return;
}
// - Otherwise, a temporary of type "cv1 T1" is created and initialized
// from the initializer expression using the rules for a non-reference
// copy-initialization (8.5). The reference is then bound to the
// temporary. [...]
// Ignore address space of reference type at this point and perform address
// space conversion after the reference binding step.
QualType cv1T1IgnoreAS =
T1Quals.hasAddressSpace()
? S.Context.getQualifiedType(T1, T1Quals.withoutAddressSpace())
: cv1T1;
InitializedEntity TempEntity =
InitializedEntity::InitializeTemporary(cv1T1IgnoreAS);
// FIXME: Why do we use an implicit conversion here rather than trying
// copy-initialization?
ImplicitConversionSequence ICS
= S.TryImplicitConversion(Initializer, TempEntity.getType(),
/*SuppressUserConversions=*/false,
Sema::AllowedExplicit::None,
/*FIXME:InOverloadResolution=*/false,
/*CStyle=*/Kind.isCStyleOrFunctionalCast(),
/*AllowObjCWritebackConversion=*/false);
if (ICS.isBad()) {
// FIXME: Use the conversion function set stored in ICS to turn
// this into an overloading ambiguity diagnostic. However, we need
// to keep that set as an OverloadCandidateSet rather than as some
// other kind of set.
if (ConvOvlResult && !Sequence.getFailedCandidateSet().empty())
Sequence.SetOverloadFailure(
InitializationSequence::FK_ReferenceInitOverloadFailed,
ConvOvlResult);
else if (S.Context.getCanonicalType(T2) == S.Context.OverloadTy)
Sequence.SetFailed(InitializationSequence::FK_AddressOfOverloadFailed);
else
Sequence.SetFailed(InitializationSequence::FK_ReferenceInitFailed);
return;
} else {
Sequence.AddConversionSequenceStep(ICS, TempEntity.getType());
}
// [...] If T1 is reference-related to T2, cv1 must be the
// same cv-qualification as, or greater cv-qualification
// than, cv2; otherwise, the program is ill-formed.
unsigned T1CVRQuals = T1Quals.getCVRQualifiers();
unsigned T2CVRQuals = T2Quals.getCVRQualifiers();
if ((RefRelationship == Sema::Ref_Related &&
(T1CVRQuals | T2CVRQuals) != T1CVRQuals) ||
!T1Quals.isAddressSpaceSupersetOf(T2Quals)) {
Sequence.SetFailed(InitializationSequence::FK_ReferenceInitDropsQualifiers);
return;
}
// [...] If T1 is reference-related to T2 and the reference is an rvalue
// reference, the initializer expression shall not be an lvalue.
if (RefRelationship >= Sema::Ref_Related && !isLValueRef &&
InitCategory.isLValue()) {
Sequence.SetFailed(
InitializationSequence::FK_RValueReferenceBindingToLValue);
return;
}
Sequence.AddReferenceBindingStep(cv1T1IgnoreAS, /*BindingTemporary=*/true);
if (T1Quals.hasAddressSpace()) {
if (!Qualifiers::isAddressSpaceSupersetOf(T1Quals.getAddressSpace(),
LangAS::Default)) {
Sequence.SetFailed(
InitializationSequence::FK_ReferenceAddrspaceMismatchTemporary);
return;
}
Sequence.AddQualificationConversionStep(cv1T1, isLValueRef ? VK_LValue
: VK_XValue);
}
}
/// Attempt character array initialization from a string literal
/// (C++ [dcl.init.string], C99 6.7.8).
static void TryStringLiteralInitialization(Sema &S,
const InitializedEntity &Entity,
const InitializationKind &Kind,
Expr *Initializer,
InitializationSequence &Sequence) {
Sequence.AddStringInitStep(Entity.getType());
}
/// Attempt value initialization (C++ [dcl.init]p7).
static void TryValueInitialization(Sema &S,
const InitializedEntity &Entity,
const InitializationKind &Kind,
InitializationSequence &Sequence,
InitListExpr *InitList) {
assert((!InitList || InitList->getNumInits() == 0) &&
"Shouldn't use value-init for non-empty init lists");
// C++98 [dcl.init]p5, C++11 [dcl.init]p7:
//
// To value-initialize an object of type T means:
QualType T = Entity.getType();
// -- if T is an array type, then each element is value-initialized;
T = S.Context.getBaseElementType(T);
if (const RecordType *RT = T->getAs<RecordType>()) {
if (CXXRecordDecl *ClassDecl = dyn_cast<CXXRecordDecl>(RT->getDecl())) {
bool NeedZeroInitialization = true;
// C++98:
// -- if T is a class type (clause 9) with a user-declared constructor
// (12.1), then the default constructor for T is called (and the
// initialization is ill-formed if T has no accessible default
// constructor);
// C++11:
// -- if T is a class type (clause 9) with either no default constructor
// (12.1 [class.ctor]) or a default constructor that is user-provided
// or deleted, then the object is default-initialized;
//
// Note that the C++11 rule is the same as the C++98 rule if there are no
// defaulted or deleted constructors, so we just use it unconditionally.
CXXConstructorDecl *CD = S.LookupDefaultConstructor(ClassDecl);
if (!CD || !CD->getCanonicalDecl()->isDefaulted() || CD->isDeleted())
NeedZeroInitialization = false;
// -- if T is a (possibly cv-qualified) non-union class type without a
// user-provided or deleted default constructor, then the object is
// zero-initialized and, if T has a non-trivial default constructor,
// default-initialized;
// The 'non-union' here was removed by DR1502. The 'non-trivial default
// constructor' part was removed by DR1507.
if (NeedZeroInitialization)
Sequence.AddZeroInitializationStep(Entity.getType());
// C++03:
// -- if T is a non-union class type without a user-declared constructor,
// then every non-static data member and base class component of T is
// value-initialized;
// [...] A program that calls for [...] value-initialization of an
// entity of reference type is ill-formed.
//
// C++11 doesn't need this handling, because value-initialization does not
// occur recursively there, and the implicit default constructor is
// defined as deleted in the problematic cases.
if (!S.getLangOpts().CPlusPlus11 &&
ClassDecl->hasUninitializedReferenceMember()) {
Sequence.SetFailed(InitializationSequence::FK_TooManyInitsForReference);
return;
}
// If this is list-value-initialization, pass the empty init list on when
// building the constructor call. This affects the semantics of a few
// things (such as whether an explicit default constructor can be called).
Expr *InitListAsExpr = InitList;
MultiExprArg Args(&InitListAsExpr, InitList ? 1 : 0);
bool InitListSyntax = InitList;
// FIXME: Instead of creating a CXXConstructExpr of array type here,
// wrap a class-typed CXXConstructExpr in an ArrayInitLoopExpr.
return TryConstructorInitialization(
S, Entity, Kind, Args, T, Entity.getType(), Sequence, InitListSyntax);
}
}
Sequence.AddZeroInitializationStep(Entity.getType());
}
/// Attempt default initialization (C++ [dcl.init]p6).
static void TryDefaultInitialization(Sema &S,
const InitializedEntity &Entity,
const InitializationKind &Kind,
InitializationSequence &Sequence) {
assert(Kind.getKind() == InitializationKind::IK_Default);
// C++ [dcl.init]p6:
// To default-initialize an object of type T means:
// - if T is an array type, each element is default-initialized;
QualType DestType = S.Context.getBaseElementType(Entity.getType());
// - if T is a (possibly cv-qualified) class type (Clause 9), the default
// constructor for T is called (and the initialization is ill-formed if
// T has no accessible default constructor);
if (DestType->isRecordType() && S.getLangOpts().CPlusPlus) {
TryConstructorInitialization(S, Entity, Kind, None, DestType,
Entity.getType(), Sequence);
return;
}
// - otherwise, no initialization is performed.
// If a program calls for the default initialization of an object of
// a const-qualified type T, T shall be a class type with a user-provided
// default constructor.
if (DestType.isConstQualified() && S.getLangOpts().CPlusPlus) {
if (!maybeRecoverWithZeroInitialization(S, Sequence, Entity))
Sequence.SetFailed(InitializationSequence::FK_DefaultInitOfConst);
return;
}
// If the destination type has a lifetime property, zero-initialize it.
if (DestType.getQualifiers().hasObjCLifetime()) {
Sequence.AddZeroInitializationStep(Entity.getType());
return;
}
}
/// Attempt a user-defined conversion between two types (C++ [dcl.init]),
/// which enumerates all conversion functions and performs overload resolution
/// to select the best.
static void TryUserDefinedConversion(Sema &S,
QualType DestType,
const InitializationKind &Kind,
Expr *Initializer,
InitializationSequence &Sequence,
bool TopLevelOfInitList) {
assert(!DestType->isReferenceType() && "References are handled elsewhere");
QualType SourceType = Initializer->getType();
assert((DestType->isRecordType() || SourceType->isRecordType()) &&
"Must have a class type to perform a user-defined conversion");
// Build the candidate set directly in the initialization sequence
// structure, so that it will persist if we fail.
OverloadCandidateSet &CandidateSet = Sequence.getFailedCandidateSet();
CandidateSet.clear(OverloadCandidateSet::CSK_InitByUserDefinedConversion);
CandidateSet.setDestAS(DestType.getQualifiers().getAddressSpace());
// Determine whether we are allowed to call explicit constructors or
// explicit conversion operators.
bool AllowExplicit = Kind.AllowExplicit();
if (const RecordType *DestRecordType = DestType->getAs<RecordType>()) {
// The type we're converting to is a class type. Enumerate its constructors
// to see if there is a suitable conversion.
CXXRecordDecl *DestRecordDecl
= cast<CXXRecordDecl>(DestRecordType->getDecl());
// Try to complete the type we're converting to.
if (S.isCompleteType(Kind.getLocation(), DestType)) {
for (NamedDecl *D : S.LookupConstructors(DestRecordDecl)) {
auto Info = getConstructorInfo(D);
if (!Info.Constructor)
continue;
if (!Info.Constructor->isInvalidDecl() &&
Info.Constructor->isConvertingConstructor(/*AllowExplicit*/true)) {
if (Info.ConstructorTmpl)
S.AddTemplateOverloadCandidate(
Info.ConstructorTmpl, Info.FoundDecl,
/*ExplicitArgs*/ nullptr, Initializer, CandidateSet,
/*SuppressUserConversions=*/true,
/*PartialOverloading*/ false, AllowExplicit);
else
S.AddOverloadCandidate(Info.Constructor, Info.FoundDecl,
Initializer, CandidateSet,
/*SuppressUserConversions=*/true,
/*PartialOverloading*/ false, AllowExplicit);
}
}
}
}
SourceLocation DeclLoc = Initializer->getBeginLoc();
if (const RecordType *SourceRecordType = SourceType->getAs<RecordType>()) {
// The type we're converting from is a class type, enumerate its conversion
// functions.
// We can only enumerate the conversion functions for a complete type; if
// the type isn't complete, simply skip this step.
if (S.isCompleteType(DeclLoc, SourceType)) {
CXXRecordDecl *SourceRecordDecl
= cast<CXXRecordDecl>(SourceRecordType->getDecl());
const auto &Conversions =
SourceRecordDecl->getVisibleConversionFunctions();
for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
NamedDecl *D = *I;
CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(D->getDeclContext());
if (isa<UsingShadowDecl>(D))
D = cast<UsingShadowDecl>(D)->getTargetDecl();
FunctionTemplateDecl *ConvTemplate = dyn_cast<FunctionTemplateDecl>(D);
CXXConversionDecl *Conv;
if (ConvTemplate)
Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
else
Conv = cast<CXXConversionDecl>(D);
if (ConvTemplate)
S.AddTemplateConversionCandidate(
ConvTemplate, I.getPair(), ActingDC, Initializer, DestType,
CandidateSet, AllowExplicit, AllowExplicit);
else
S.AddConversionCandidate(Conv, I.getPair(), ActingDC, Initializer,
DestType, CandidateSet, AllowExplicit,
AllowExplicit);
}
}
}
// Perform overload resolution. If it fails, return the failed result.
OverloadCandidateSet::iterator Best;
if (OverloadingResult Result
= CandidateSet.BestViableFunction(S, DeclLoc, Best)) {
Sequence.SetOverloadFailure(
InitializationSequence::FK_UserConversionOverloadFailed, Result);
// [class.copy.elision]p3:
// In some copy-initialization contexts, a two-stage overload resolution
// is performed.
// If the first overload resolution selects a deleted function, we also
// need the initialization sequence to decide whether to perform the second
// overload resolution.
if (!(Result == OR_Deleted &&
Kind.getKind() == InitializationKind::IK_Copy))
return;
}
FunctionDecl *Function = Best->Function;
Function->setReferenced();
bool HadMultipleCandidates = (CandidateSet.size() > 1);
if (isa<CXXConstructorDecl>(Function)) {
// Add the user-defined conversion step. Any cv-qualification conversion is
// subsumed by the initialization. Per DR5, the created temporary is of the
// cv-unqualified type of the destination.
Sequence.AddUserConversionStep(Function, Best->FoundDecl,
DestType.getUnqualifiedType(),
HadMultipleCandidates);
// C++14 and before:
// - if the function is a constructor, the call initializes a temporary
// of the cv-unqualified version of the destination type. The [...]
// temporary [...] is then used to direct-initialize, according to the
// rules above, the object that is the destination of the
// copy-initialization.
// Note that this just performs a simple object copy from the temporary.
//
// C++17:
// - if the function is a constructor, the call is a prvalue of the
// cv-unqualified version of the destination type whose return object
// is initialized by the constructor. The call is used to
// direct-initialize, according to the rules above, the object that
// is the destination of the copy-initialization.
// Therefore we need to do nothing further.
//
// FIXME: Mark this copy as extraneous.
if (!S.getLangOpts().CPlusPlus17)
Sequence.AddFinalCopy(DestType);
else if (DestType.hasQualifiers())
Sequence.AddQualificationConversionStep(DestType, VK_RValue);
return;
}
// Add the user-defined conversion step that calls the conversion function.
QualType ConvType = Function->getCallResultType();
Sequence.AddUserConversionStep(Function, Best->FoundDecl, ConvType,
HadMultipleCandidates);
if (ConvType->getAs<RecordType>()) {
// The call is used to direct-initialize [...] the object that is the
// destination of the copy-initialization.
//
// In C++17, this does not call a constructor if we enter /17.6.1:
// - If the initializer expression is a prvalue and the cv-unqualified
// version of the source type is the same as the class of the
// destination [... do not make an extra copy]
//
// FIXME: Mark this copy as extraneous.
if (!S.getLangOpts().CPlusPlus17 ||
Function->getReturnType()->isReferenceType() ||
!S.Context.hasSameUnqualifiedType(ConvType, DestType))
Sequence.AddFinalCopy(DestType);
else if (!S.Context.hasSameType(ConvType, DestType))
Sequence.AddQualificationConversionStep(DestType, VK_RValue);
return;
}
// If the conversion following the call to the conversion function
// is interesting, add it as a separate step.
if (Best->FinalConversion.First || Best->FinalConversion.Second ||
Best->FinalConversion.Third) {
ImplicitConversionSequence ICS;
ICS.setStandard();
ICS.Standard = Best->FinalConversion;
Sequence.AddConversionSequenceStep(ICS, DestType, TopLevelOfInitList);
}
}
/// An egregious hack for compatibility with libstdc++-4.2: in <tr1/hashtable>,
/// a function with a pointer return type contains a 'return false;' statement.
/// In C++11, 'false' is not a null pointer, so this breaks the build of any
/// code using that header.
///
/// Work around this by treating 'return false;' as zero-initializing the result
/// if it's used in a pointer-returning function in a system header.
static bool isLibstdcxxPointerReturnFalseHack(Sema &S,
const InitializedEntity &Entity,
const Expr *Init) {
return S.getLangOpts().CPlusPlus11 &&
Entity.getKind() == InitializedEntity::EK_Result &&
Entity.getType()->isPointerType() &&
isa<CXXBoolLiteralExpr>(Init) &&
!cast<CXXBoolLiteralExpr>(Init)->getValue() &&
S.getSourceManager().isInSystemHeader(Init->getExprLoc());
}
/// The non-zero enum values here are indexes into diagnostic alternatives.
enum InvalidICRKind { IIK_okay, IIK_nonlocal, IIK_nonscalar };
/// Determines whether this expression is an acceptable ICR source.
static InvalidICRKind isInvalidICRSource(ASTContext &C, Expr *e,
bool isAddressOf, bool &isWeakAccess) {
// Skip parens.
e = e->IgnoreParens();
// Skip address-of nodes.
if (UnaryOperator *op = dyn_cast<UnaryOperator>(e)) {
if (op->getOpcode() == UO_AddrOf)
return isInvalidICRSource(C, op->getSubExpr(), /*addressof*/ true,
isWeakAccess);
// Skip certain casts.
} else if (CastExpr *ce = dyn_cast<CastExpr>(e)) {
switch (ce->getCastKind()) {
case CK_Dependent:
case CK_BitCast:
case CK_LValueBitCast:
case CK_NoOp:
return isInvalidICRSource(C, ce->getSubExpr(), isAddressOf, isWeakAccess);
case CK_ArrayToPointerDecay:
return IIK_nonscalar;
case CK_NullToPointer:
return IIK_okay;
default:
break;
}
// If we have a declaration reference, it had better be a local variable.
} else if (isa<DeclRefExpr>(e)) {
// set isWeakAccess to true, to mean that there will be an implicit
// load which requires a cleanup.
if (e->getType().getObjCLifetime() == Qualifiers::OCL_Weak)
isWeakAccess = true;
if (!isAddressOf) return IIK_nonlocal;
VarDecl *var = dyn_cast<VarDecl>(cast<DeclRefExpr>(e)->getDecl());
if (!var) return IIK_nonlocal;
return (var->hasLocalStorage() ? IIK_okay : IIK_nonlocal);
// If we have a conditional operator, check both sides.
} else if (ConditionalOperator *cond = dyn_cast<ConditionalOperator>(e)) {
if (InvalidICRKind iik = isInvalidICRSource(C, cond->getLHS(), isAddressOf,
isWeakAccess))
return iik;
return isInvalidICRSource(C, cond->getRHS(), isAddressOf, isWeakAccess);
// These are never scalar.
} else if (isa<ArraySubscriptExpr>(e)) {
return IIK_nonscalar;
// Otherwise, it needs to be a null pointer constant.
} else {
return (e->isNullPointerConstant(C, Expr::NPC_ValueDependentIsNull)
? IIK_okay : IIK_nonlocal);
}
return IIK_nonlocal;
}
/// Check whether the given expression is a valid operand for an
/// indirect copy/restore.
static void checkIndirectCopyRestoreSource(Sema &S, Expr *src) {
assert(src->isRValue());
bool isWeakAccess = false;
InvalidICRKind iik = isInvalidICRSource(S.Context, src, false, isWeakAccess);
// If isWeakAccess to true, there will be an implicit
// load which requires a cleanup.
if (S.getLangOpts().ObjCAutoRefCount && isWeakAccess)
S.Cleanup.setExprNeedsCleanups(true);
if (iik == IIK_okay) return;
S.Diag(src->getExprLoc(), diag::err_arc_nonlocal_writeback)
<< ((unsigned) iik - 1) // shift index into diagnostic explanations
<< src->getSourceRange();
}
/// Determine whether we have compatible array types for the
/// purposes of GNU by-copy array initialization.
static bool hasCompatibleArrayTypes(ASTContext &Context, const ArrayType *Dest,
const ArrayType *Source) {
// If the source and destination array types are equivalent, we're
// done.
if (Context.hasSameType(QualType(Dest, 0), QualType(Source, 0)))
return true;
// Make sure that the element types are the same.
if (!Context.hasSameType(Dest->getElementType(), Source->getElementType()))
return false;
// The only mismatch we allow is when the destination is an
// incomplete array type and the source is a constant array type.
return Source->isConstantArrayType() && Dest->isIncompleteArrayType();
}
static bool tryObjCWritebackConversion(Sema &S,
InitializationSequence &Sequence,
const InitializedEntity &Entity,
Expr *Initializer) {
bool ArrayDecay = false;
QualType ArgType = Initializer->getType();
QualType ArgPointee;
if (const ArrayType *ArgArrayType = S.Context.getAsArrayType(ArgType)) {
ArrayDecay = true;
ArgPointee = ArgArrayType->getElementType();
ArgType = S.Context.getPointerType(ArgPointee);
}
// Handle write-back conversion.
QualType ConvertedArgType;
if (!S.isObjCWritebackConversion(ArgType, Entity.getType(),
ConvertedArgType))
return false;
// We should copy unless we're passing to an argument explicitly
// marked 'out'.
bool ShouldCopy = true;
if (ParmVarDecl *param = cast_or_null<ParmVarDecl>(Entity.getDecl()))
ShouldCopy = (param->getObjCDeclQualifier() != ParmVarDecl::OBJC_TQ_Out);
// Do we need an lvalue conversion?
if (ArrayDecay || Initializer->isGLValue()) {
ImplicitConversionSequence ICS;
ICS.setStandard();
ICS.Standard.setAsIdentityConversion();
QualType ResultType;
if (ArrayDecay) {
ICS.Standard.First = ICK_Array_To_Pointer;
ResultType = S.Context.getPointerType(ArgPointee);
} else {
ICS.Standard.First = ICK_Lvalue_To_Rvalue;
ResultType = Initializer->getType().getNonLValueExprType(S.Context);
}
Sequence.AddConversionSequenceStep(ICS, ResultType);
}
Sequence.AddPassByIndirectCopyRestoreStep(Entity.getType(), ShouldCopy);
return true;
}
static bool TryOCLSamplerInitialization(Sema &S,
InitializationSequence &Sequence,
QualType DestType,
Expr *Initializer) {
if (!S.getLangOpts().OpenCL || !DestType->isSamplerT() ||
(!Initializer->isIntegerConstantExpr(S.Context) &&
!Initializer->getType()->isSamplerT()))
return false;
Sequence.AddOCLSamplerInitStep(DestType);
return true;
}
static bool IsZeroInitializer(Expr *Initializer, Sema &S) {
return Initializer->isIntegerConstantExpr(S.getASTContext()) &&
(Initializer->EvaluateKnownConstInt(S.getASTContext()) == 0);
}
static bool TryOCLZeroOpaqueTypeInitialization(Sema &S,
InitializationSequence &Sequence,
QualType DestType,
Expr *Initializer) {
if (!S.getLangOpts().OpenCL)
return false;
//
// OpenCL 1.2 spec, s6.12.10
//
// The event argument can also be used to associate the
// async_work_group_copy with a previous async copy allowing
// an event to be shared by multiple async copies; otherwise
// event should be zero.
//
if (DestType->isEventT() || DestType->isQueueT()) {
if (!IsZeroInitializer(Initializer, S))
return false;
Sequence.AddOCLZeroOpaqueTypeStep(DestType);
return true;
}
// We should allow zero initialization for all types defined in the
// cl_intel_device_side_avc_motion_estimation extension, except
// intel_sub_group_avc_mce_payload_t and intel_sub_group_avc_mce_result_t.
if (S.getOpenCLOptions().isEnabled(
"cl_intel_device_side_avc_motion_estimation") &&
DestType->isOCLIntelSubgroupAVCType()) {
if (DestType->isOCLIntelSubgroupAVCMcePayloadType() ||
DestType->isOCLIntelSubgroupAVCMceResultType())
return false;
if (!IsZeroInitializer(Initializer, S))
return false;
Sequence.AddOCLZeroOpaqueTypeStep(DestType);
return true;
}
return false;
}
InitializationSequence::InitializationSequence(
Sema &S, const InitializedEntity &Entity, const InitializationKind &Kind,
MultiExprArg Args, bool TopLevelOfInitList, bool TreatUnavailableAsInvalid)
: FailedOverloadResult(OR_Success),
FailedCandidateSet(Kind.getLocation(), OverloadCandidateSet::CSK_Normal) {
InitializeFrom(S, Entity, Kind, Args, TopLevelOfInitList,
TreatUnavailableAsInvalid);
}
/// Tries to get a FunctionDecl out of `E`. If it succeeds and we can take the
/// address of that function, this returns true. Otherwise, it returns false.
static bool isExprAnUnaddressableFunction(Sema &S, const Expr *E) {
auto *DRE = dyn_cast<DeclRefExpr>(E);
if (!DRE || !isa<FunctionDecl>(DRE->getDecl()))
return false;
return !S.checkAddressOfFunctionIsAvailable(
cast<FunctionDecl>(DRE->getDecl()));
}
/// Determine whether we can perform an elementwise array copy for this kind
/// of entity.
static bool canPerformArrayCopy(const InitializedEntity &Entity) {
switch (Entity.getKind()) {
case InitializedEntity::EK_LambdaCapture:
// C++ [expr.prim.lambda]p24:
// For array members, the array elements are direct-initialized in
// increasing subscript order.
return true;
case InitializedEntity::EK_Variable:
// C++ [dcl.decomp]p1:
// [...] each element is copy-initialized or direct-initialized from the
// corresponding element of the assignment-expression [...]
return isa<DecompositionDecl>(Entity.getDecl());
case InitializedEntity::EK_Member:
// C++ [class.copy.ctor]p14:
// - if the member is an array, each element is direct-initialized with
// the corresponding subobject of x
return Entity.isImplicitMemberInitializer();
case InitializedEntity::EK_ArrayElement:
// All the above cases are intended to apply recursively, even though none
// of them actually say that.
if (auto *E = Entity.getParent())
return canPerformArrayCopy(*E);
break;
default:
break;
}
return false;
}
void InitializationSequence::InitializeFrom(Sema &S,
const InitializedEntity &Entity,
const InitializationKind &Kind,
MultiExprArg Args,
bool TopLevelOfInitList,
bool TreatUnavailableAsInvalid) {
ASTContext &Context = S.Context;
// Eliminate non-overload placeholder types in the arguments. We
// need to do this before checking whether types are dependent
// because lowering a pseudo-object expression might well give us
// something of dependent type.
for (unsigned I = 0, E = Args.size(); I != E; ++I)
if (Args[I]->getType()->isNonOverloadPlaceholderType()) {
// FIXME: should we be doing this here?
ExprResult result = S.CheckPlaceholderExpr(Args[I]);
if (result.isInvalid()) {
SetFailed(FK_PlaceholderType);
return;
}
Args[I] = result.get();
}
// C++0x [dcl.init]p16:
// The semantics of initializers are as follows. The destination type is
// the type of the object or reference being initialized and the source
// type is the type of the initializer expression. The source type is not
// defined when the initializer is a braced-init-list or when it is a
// parenthesized list of expressions.
QualType DestType = Entity.getType();
if (DestType->isDependentType() ||
Expr::hasAnyTypeDependentArguments(Args)) {
SequenceKind = DependentSequence;
return;
}
// Almost everything is a normal sequence.
setSequenceKind(NormalSequence);
QualType SourceType;
Expr *Initializer = nullptr;
if (Args.size() == 1) {
Initializer = Args[0];
if (S.getLangOpts().ObjC) {
if (S.CheckObjCBridgeRelatedConversions(Initializer->getBeginLoc(),
DestType, Initializer->getType(),
Initializer) ||
S.CheckConversionToObjCLiteral(DestType, Initializer))
Args[0] = Initializer;
}
if (!isa<InitListExpr>(Initializer))
SourceType = Initializer->getType();
}
// - If the initializer is a (non-parenthesized) braced-init-list, the
// object is list-initialized (8.5.4).
if (Kind.getKind() != InitializationKind::IK_Direct) {
if (InitListExpr *InitList = dyn_cast_or_null<InitListExpr>(Initializer)) {
TryListInitialization(S, Entity, Kind, InitList, *this,
TreatUnavailableAsInvalid);
return;
}
}
// - If the destination type is a reference type, see 8.5.3.
if (DestType->isReferenceType()) {
// C++0x [dcl.init.ref]p1:
// A variable declared to be a T& or T&&, that is, "reference to type T"
// (8.3.2), shall be initialized by an object, or function, of type T or
// by an object that can be converted into a T.
// (Therefore, multiple arguments are not permitted.)
if (Args.size() != 1)
SetFailed(FK_TooManyInitsForReference);
// C++17 [dcl.init.ref]p5:
// A reference [...] is initialized by an expression [...] as follows:
// If the initializer is not an expression, presumably we should reject,
// but the standard fails to actually say so.
else if (isa<InitListExpr>(Args[0]))
SetFailed(FK_ParenthesizedListInitForReference);
else
TryReferenceInitialization(S, Entity, Kind, Args[0], *this);
return;
}
// - If the initializer is (), the object is value-initialized.
if (Kind.getKind() == InitializationKind::IK_Value ||
(Kind.getKind() == InitializationKind::IK_Direct && Args.empty())) {
TryValueInitialization(S, Entity, Kind, *this);
return;
}
// Handle default initialization.
if (Kind.getKind() == InitializationKind::IK_Default) {
TryDefaultInitialization(S, Entity, Kind, *this);
return;
}
// - If the destination type is an array of characters, an array of
// char16_t, an array of char32_t, or an array of wchar_t, and the
// initializer is a string literal, see 8.5.2.
// - Otherwise, if the destination type is an array, the program is
// ill-formed.
if (const ArrayType *DestAT = Context.getAsArrayType(DestType)) {
if (Initializer && isa<VariableArrayType>(DestAT)) {
SetFailed(FK_VariableLengthArrayHasInitializer);
return;
}
if (Initializer) {
switch (IsStringInit(Initializer, DestAT, Context)) {
case SIF_None:
TryStringLiteralInitialization(S, Entity, Kind, Initializer, *this);
return;
case SIF_NarrowStringIntoWideChar:
SetFailed(FK_NarrowStringIntoWideCharArray);
return;
case SIF_WideStringIntoChar:
SetFailed(FK_WideStringIntoCharArray);
return;
case SIF_IncompatWideStringIntoWideChar:
SetFailed(FK_IncompatWideStringIntoWideChar);
return;
case SIF_PlainStringIntoUTF8Char:
SetFailed(FK_PlainStringIntoUTF8Char);
return;
case SIF_UTF8StringIntoPlainChar:
SetFailed(FK_UTF8StringIntoPlainChar);
return;
case SIF_Other:
break;
}
}
// Some kinds of initialization permit an array to be initialized from
// another array of the same type, and perform elementwise initialization.
if (Initializer && isa<ConstantArrayType>(DestAT) &&
S.Context.hasSameUnqualifiedType(Initializer->getType(),
Entity.getType()) &&
canPerformArrayCopy(Entity)) {
// If source is a prvalue, use it directly.
if (Initializer->getValueKind() == VK_RValue) {
AddArrayInitStep(DestType, /*IsGNUExtension*/false);
return;
}
// Emit element-at-a-time copy loop.
InitializedEntity Element =
InitializedEntity::InitializeElement(S.Context, 0, Entity);
QualType InitEltT =
Context.getAsArrayType(Initializer->getType())->getElementType();
OpaqueValueExpr OVE(Initializer->getExprLoc(), InitEltT,
Initializer->getValueKind(),
Initializer->getObjectKind());
Expr *OVEAsExpr = &OVE;
InitializeFrom(S, Element, Kind, OVEAsExpr, TopLevelOfInitList,
TreatUnavailableAsInvalid);
if (!Failed())
AddArrayInitLoopStep(Entity.getType(), InitEltT);
return;
}
// Note: as an GNU C extension, we allow initialization of an
// array from a compound literal that creates an array of the same
// type, so long as the initializer has no side effects.
if (!S.getLangOpts().CPlusPlus && Initializer &&
isa<CompoundLiteralExpr>(Initializer->IgnoreParens()) &&
Initializer->getType()->isArrayType()) {
const ArrayType *SourceAT
= Context.getAsArrayType(Initializer->getType());
if (!hasCompatibleArrayTypes(S.Context, DestAT, SourceAT))
SetFailed(FK_ArrayTypeMismatch);
else if (Initializer->HasSideEffects(S.Context))
SetFailed(FK_NonConstantArrayInit);
else {
AddArrayInitStep(DestType, /*IsGNUExtension*/true);
}
}
// Note: as a GNU C++ extension, we allow list-initialization of a
// class member of array type from a parenthesized initializer list.
else if (S.getLangOpts().CPlusPlus &&
Entity.getKind() == InitializedEntity::EK_Member &&
Initializer && isa<InitListExpr>(Initializer)) {
TryListInitialization(S, Entity, Kind, cast<InitListExpr>(Initializer),
*this, TreatUnavailableAsInvalid);
AddParenthesizedArrayInitStep(DestType);
} else if (DestAT->getElementType()->isCharType())
SetFailed(FK_ArrayNeedsInitListOrStringLiteral);
else if (IsWideCharCompatible(DestAT->getElementType(), Context))
SetFailed(FK_ArrayNeedsInitListOrWideStringLiteral);
else
SetFailed(FK_ArrayNeedsInitList);
return;
}
// Determine whether we should consider writeback conversions for
// Objective-C ARC.
bool allowObjCWritebackConversion = S.getLangOpts().ObjCAutoRefCount &&
Entity.isParameterKind();
if (TryOCLSamplerInitialization(S, *this, DestType, Initializer))
return;
// We're at the end of the line for C: it's either a write-back conversion
// or it's a C assignment. There's no need to check anything else.
if (!S.getLangOpts().CPlusPlus) {
// If allowed, check whether this is an Objective-C writeback conversion.
if (allowObjCWritebackConversion &&
tryObjCWritebackConversion(S, *this, Entity, Initializer)) {
return;
}
if (TryOCLZeroOpaqueTypeInitialization(S, *this, DestType, Initializer))
return;
// Handle initialization in C
AddCAssignmentStep(DestType);
MaybeProduceObjCObject(S, *this, Entity);
return;
}
assert(S.getLangOpts().CPlusPlus);
// - If the destination type is a (possibly cv-qualified) class type:
if (DestType->isRecordType()) {
// - If the initialization is direct-initialization, or if it is
// copy-initialization where the cv-unqualified version of the
// source type is the same class as, or a derived class of, the
// class of the destination, constructors are considered. [...]
if (Kind.getKind() == InitializationKind::IK_Direct ||
(Kind.getKind() == InitializationKind::IK_Copy &&
(Context.hasSameUnqualifiedType(SourceType, DestType) ||
S.IsDerivedFrom(Initializer->getBeginLoc(), SourceType, DestType))))
TryConstructorInitialization(S, Entity, Kind, Args,
DestType, DestType, *this);
// - Otherwise (i.e., for the remaining copy-initialization cases),
// user-defined conversion sequences that can convert from the source
// type to the destination type or (when a conversion function is
// used) to a derived class thereof are enumerated as described in
// 13.3.1.4, and the best one is chosen through overload resolution
// (13.3).
else
TryUserDefinedConversion(S, DestType, Kind, Initializer, *this,
TopLevelOfInitList);
return;
}
assert(Args.size() >= 1 && "Zero-argument case handled above");
// The remaining cases all need a source type.
if (Args.size() > 1) {
SetFailed(FK_TooManyInitsForScalar);
return;
} else if (isa<InitListExpr>(Args[0])) {
SetFailed(FK_ParenthesizedListInitForScalar);
return;
}
// - Otherwise, if the source type is a (possibly cv-qualified) class
// type, conversion functions are considered.
if (!SourceType.isNull() && SourceType->isRecordType()) {
// For a conversion to _Atomic(T) from either T or a class type derived
// from T, initialize the T object then convert to _Atomic type.
bool NeedAtomicConversion = false;
if (const AtomicType *Atomic = DestType->getAs<AtomicType>()) {
if (Context.hasSameUnqualifiedType(SourceType, Atomic->getValueType()) ||
S.IsDerivedFrom(Initializer->getBeginLoc(), SourceType,
Atomic->getValueType())) {
DestType = Atomic->getValueType();
NeedAtomicConversion = true;
}
}
TryUserDefinedConversion(S, DestType, Kind, Initializer, *this,
TopLevelOfInitList);
MaybeProduceObjCObject(S, *this, Entity);
if (!Failed() && NeedAtomicConversion)
AddAtomicConversionStep(Entity.getType());
return;
}
// - Otherwise, if the initialization is direct-initialization, the source
// type is std::nullptr_t, and the destination type is bool, the initial
// value of the object being initialized is false.
if (!SourceType.isNull() && SourceType->isNullPtrType() &&
DestType->isBooleanType() &&
Kind.getKind() == InitializationKind::IK_Direct) {
AddConversionSequenceStep(
ImplicitConversionSequence::getNullptrToBool(SourceType, DestType,
Initializer->isGLValue()),
DestType);
return;
}
// - Otherwise, the initial value of the object being initialized is the
// (possibly converted) value of the initializer expression. Standard
// conversions (Clause 4) will be used, if necessary, to convert the
// initializer expression to the cv-unqualified version of the
// destination type; no user-defined conversions are considered.
ImplicitConversionSequence ICS
= S.TryImplicitConversion(Initializer, DestType,
/*SuppressUserConversions*/true,
Sema::AllowedExplicit::None,
/*InOverloadResolution*/ false,
/*CStyle=*/Kind.isCStyleOrFunctionalCast(),
allowObjCWritebackConversion);
if (ICS.isStandard() &&
ICS.Standard.Second == ICK_Writeback_Conversion) {
// Objective-C ARC writeback conversion.
// We should copy unless we're passing to an argument explicitly
// marked 'out'.
bool ShouldCopy = true;
if (ParmVarDecl *Param = cast_or_null<ParmVarDecl>(Entity.getDecl()))
ShouldCopy = (Param->getObjCDeclQualifier() != ParmVarDecl::OBJC_TQ_Out);
// If there was an lvalue adjustment, add it as a separate conversion.
if (ICS.Standard.First == ICK_Array_To_Pointer ||
ICS.Standard.First == ICK_Lvalue_To_Rvalue) {
ImplicitConversionSequence LvalueICS;
LvalueICS.setStandard();
LvalueICS.Standard.setAsIdentityConversion();
LvalueICS.Standard.setAllToTypes(ICS.Standard.getToType(0));
LvalueICS.Standard.First = ICS.Standard.First;
AddConversionSequenceStep(LvalueICS, ICS.Standard.getToType(0));
}
AddPassByIndirectCopyRestoreStep(DestType, ShouldCopy);
} else if (ICS.isBad()) {
DeclAccessPair dap;
if (isLibstdcxxPointerReturnFalseHack(S, Entity, Initializer)) {
AddZeroInitializationStep(Entity.getType());
} else if (Initializer->getType() == Context.OverloadTy &&
!S.ResolveAddressOfOverloadedFunction(Initializer, DestType,
false, dap))
SetFailed(InitializationSequence::FK_AddressOfOverloadFailed);
else if (Initializer->getType()->isFunctionType() &&
isExprAnUnaddressableFunction(S, Initializer))
SetFailed(InitializationSequence::FK_AddressOfUnaddressableFunction);
else
SetFailed(InitializationSequence::FK_ConversionFailed);
} else {
AddConversionSequenceStep(ICS, DestType, TopLevelOfInitList);
MaybeProduceObjCObject(S, *this, Entity);
}
}
InitializationSequence::~InitializationSequence() {
for (auto &S : Steps)
S.Destroy();
}
//===----------------------------------------------------------------------===//
// Perform initialization
//===----------------------------------------------------------------------===//
static Sema::AssignmentAction
getAssignmentAction(const InitializedEntity &Entity, bool Diagnose = false) {
switch(Entity.getKind()) {
case InitializedEntity::EK_Variable:
case InitializedEntity::EK_New:
case InitializedEntity::EK_Exception:
case InitializedEntity::EK_Base:
case InitializedEntity::EK_Delegating:
return Sema::AA_Initializing;
case InitializedEntity::EK_Parameter:
if (Entity.getDecl() &&
isa<ObjCMethodDecl>(Entity.getDecl()->getDeclContext()))
return Sema::AA_Sending;
return Sema::AA_Passing;
case InitializedEntity::EK_Parameter_CF_Audited:
if (Entity.getDecl() &&
isa<ObjCMethodDecl>(Entity.getDecl()->getDeclContext()))
return Sema::AA_Sending;
return !Diagnose ? Sema::AA_Passing : Sema::AA_Passing_CFAudited;
case InitializedEntity::EK_Result:
case InitializedEntity::EK_StmtExprResult: // FIXME: Not quite right.
return Sema::AA_Returning;
case InitializedEntity::EK_Temporary:
case InitializedEntity::EK_RelatedResult:
// FIXME: Can we tell apart casting vs. converting?
return Sema::AA_Casting;
case InitializedEntity::EK_TemplateParameter:
// This is really initialization, but refer to it as conversion for
// consistency with CheckConvertedConstantExpression.
return Sema::AA_Converting;
case InitializedEntity::EK_Member:
case InitializedEntity::EK_Binding:
case InitializedEntity::EK_ArrayElement:
case InitializedEntity::EK_VectorElement:
case InitializedEntity::EK_ComplexElement:
case InitializedEntity::EK_BlockElement:
case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
case InitializedEntity::EK_LambdaCapture:
case InitializedEntity::EK_CompoundLiteralInit:
return Sema::AA_Initializing;
}
llvm_unreachable("Invalid EntityKind!");
}
/// Whether we should bind a created object as a temporary when
/// initializing the given entity.
static bool shouldBindAsTemporary(const InitializedEntity &Entity) {
switch (Entity.getKind()) {
case InitializedEntity::EK_ArrayElement:
case InitializedEntity::EK_Member:
case InitializedEntity::EK_Result:
case InitializedEntity::EK_StmtExprResult:
case InitializedEntity::EK_New:
case InitializedEntity::EK_Variable:
case InitializedEntity::EK_Base:
case InitializedEntity::EK_Delegating:
case InitializedEntity::EK_VectorElement:
case InitializedEntity::EK_ComplexElement:
case InitializedEntity::EK_Exception:
case InitializedEntity::EK_BlockElement:
case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
case InitializedEntity::EK_LambdaCapture:
case InitializedEntity::EK_CompoundLiteralInit:
case InitializedEntity::EK_TemplateParameter:
return false;
case InitializedEntity::EK_Parameter:
case InitializedEntity::EK_Parameter_CF_Audited:
case InitializedEntity::EK_Temporary:
case InitializedEntity::EK_RelatedResult:
case InitializedEntity::EK_Binding:
return true;
}
llvm_unreachable("missed an InitializedEntity kind?");
}
/// Whether the given entity, when initialized with an object
/// created for that initialization, requires destruction.
static bool shouldDestroyEntity(const InitializedEntity &Entity) {
switch (Entity.getKind()) {
case InitializedEntity::EK_Result:
case InitializedEntity::EK_StmtExprResult:
case InitializedEntity::EK_New:
case InitializedEntity::EK_Base:
case InitializedEntity::EK_Delegating:
case InitializedEntity::EK_VectorElement:
case InitializedEntity::EK_ComplexElement:
case InitializedEntity::EK_BlockElement:
case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
case InitializedEntity::EK_LambdaCapture:
return false;
case InitializedEntity::EK_Member:
case InitializedEntity::EK_Binding:
case InitializedEntity::EK_Variable:
case InitializedEntity::EK_Parameter:
case InitializedEntity::EK_Parameter_CF_Audited:
case InitializedEntity::EK_TemplateParameter:
case InitializedEntity::EK_Temporary:
case InitializedEntity::EK_ArrayElement:
case InitializedEntity::EK_Exception:
case InitializedEntity::EK_CompoundLiteralInit:
case InitializedEntity::EK_RelatedResult:
return true;
}
llvm_unreachable("missed an InitializedEntity kind?");
}
/// Get the location at which initialization diagnostics should appear.
static SourceLocation getInitializationLoc(const InitializedEntity &Entity,
Expr *Initializer) {
switch (Entity.getKind()) {
case InitializedEntity::EK_Result:
case InitializedEntity::EK_StmtExprResult:
return Entity.getReturnLoc();
case InitializedEntity::EK_Exception:
return Entity.getThrowLoc();
case InitializedEntity::EK_Variable:
case InitializedEntity::EK_Binding:
return Entity.getDecl()->getLocation();
case InitializedEntity::EK_LambdaCapture:
return Entity.getCaptureLoc();
case InitializedEntity::EK_ArrayElement:
case InitializedEntity::EK_Member:
case InitializedEntity::EK_Parameter:
case InitializedEntity::EK_Parameter_CF_Audited:
case InitializedEntity::EK_TemplateParameter:
case InitializedEntity::EK_Temporary:
case InitializedEntity::EK_New:
case InitializedEntity::EK_Base:
case InitializedEntity::EK_Delegating:
case InitializedEntity::EK_VectorElement:
case InitializedEntity::EK_ComplexElement:
case InitializedEntity::EK_BlockElement:
case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
case InitializedEntity::EK_CompoundLiteralInit:
case InitializedEntity::EK_RelatedResult:
return Initializer->getBeginLoc();
}
llvm_unreachable("missed an InitializedEntity kind?");
}
/// Make a (potentially elidable) temporary copy of the object
/// provided by the given initializer by calling the appropriate copy
/// constructor.
///
/// \param S The Sema object used for type-checking.
///
/// \param T The type of the temporary object, which must either be
/// the type of the initializer expression or a superclass thereof.
///
/// \param Entity The entity being initialized.
///
/// \param CurInit The initializer expression.
///
/// \param IsExtraneousCopy Whether this is an "extraneous" copy that
/// is permitted in C++03 (but not C++0x) when binding a reference to
/// an rvalue.
///
/// \returns An expression that copies the initializer expression into
/// a temporary object, or an error expression if a copy could not be
/// created.
static ExprResult CopyObject(Sema &S,
QualType T,
const InitializedEntity &Entity,
ExprResult CurInit,
bool IsExtraneousCopy) {
if (CurInit.isInvalid())
return CurInit;
// Determine which class type we're copying to.
Expr *CurInitExpr = (Expr *)CurInit.get();
CXXRecordDecl *Class = nullptr;
if (const RecordType *Record = T->getAs<RecordType>())
Class = cast<CXXRecordDecl>(Record->getDecl());
if (!Class)
return CurInit;
SourceLocation Loc = getInitializationLoc(Entity, CurInit.get());
// Make sure that the type we are copying is complete.
if (S.RequireCompleteType(Loc, T, diag::err_temp_copy_incomplete))
return CurInit;
// Perform overload resolution using the class's constructors. Per
// C++11 [dcl.init]p16, second bullet for class types, this initialization
// is direct-initialization.
OverloadCandidateSet CandidateSet(Loc, OverloadCandidateSet::CSK_Normal);
DeclContext::lookup_result Ctors = S.LookupConstructors(Class);
OverloadCandidateSet::iterator Best;
switch (ResolveConstructorOverload(
S, Loc, CurInitExpr, CandidateSet, T, Ctors, Best,
/*CopyInitializing=*/false, /*AllowExplicit=*/true,
/*OnlyListConstructors=*/false, /*IsListInit=*/false,
/*SecondStepOfCopyInit=*/true)) {
case OR_Success:
break;
case OR_No_Viable_Function:
CandidateSet.NoteCandidates(
PartialDiagnosticAt(
Loc, S.PDiag(IsExtraneousCopy && !S.isSFINAEContext()
? diag::ext_rvalue_to_reference_temp_copy_no_viable
: diag::err_temp_copy_no_viable)
<< (int)Entity.getKind() << CurInitExpr->getType()
<< CurInitExpr->getSourceRange()),
S, OCD_AllCandidates, CurInitExpr);
if (!IsExtraneousCopy || S.isSFINAEContext())
return ExprError();
return CurInit;
case OR_Ambiguous:
CandidateSet.NoteCandidates(
PartialDiagnosticAt(Loc, S.PDiag(diag::err_temp_copy_ambiguous)
<< (int)Entity.getKind()
<< CurInitExpr->getType()
<< CurInitExpr->getSourceRange()),
S, OCD_AmbiguousCandidates, CurInitExpr);
return ExprError();
case OR_Deleted:
S.Diag(Loc, diag::err_temp_copy_deleted)
<< (int)Entity.getKind() << CurInitExpr->getType()
<< CurInitExpr->getSourceRange();
S.NoteDeletedFunction(Best->Function);
return ExprError();
}
bool HadMultipleCandidates = CandidateSet.size() > 1;
CXXConstructorDecl *Constructor = cast<CXXConstructorDecl>(Best->Function);
SmallVector<Expr*, 8> ConstructorArgs;
CurInit.get(); // Ownership transferred into MultiExprArg, below.
S.CheckConstructorAccess(Loc, Constructor, Best->FoundDecl, Entity,
IsExtraneousCopy);
if (IsExtraneousCopy) {
// If this is a totally extraneous copy for C++03 reference
// binding purposes, just return the original initialization
// expression. We don't generate an (elided) copy operation here
// because doing so would require us to pass down a flag to avoid
// infinite recursion, where each step adds another extraneous,
// elidable copy.
// Instantiate the default arguments of any extra parameters in
// the selected copy constructor, as if we were going to create a
// proper call to the copy constructor.
for (unsigned I = 1, N = Constructor->getNumParams(); I != N; ++I) {
ParmVarDecl *Parm = Constructor->getParamDecl(I);
if (S.RequireCompleteType(Loc, Parm->getType(),
diag::err_call_incomplete_argument))
break;
// Build the default argument expression; we don't actually care
// if this succeeds or not, because this routine will complain
// if there was a problem.
S.BuildCXXDefaultArgExpr(Loc, Constructor, Parm);
}
return CurInitExpr;
}
// Determine the arguments required to actually perform the
// constructor call (we might have derived-to-base conversions, or
// the copy constructor may have default arguments).
if (S.CompleteConstructorCall(Constructor, CurInitExpr, Loc, ConstructorArgs))
return ExprError();
// C++0x [class.copy]p32:
// When certain criteria are met, an implementation is allowed to
// omit the copy/move construction of a class object, even if the
// copy/move constructor and/or destructor for the object have
// side effects. [...]
// - when a temporary class object that has not been bound to a
// reference (12.2) would be copied/moved to a class object
// with the same cv-unqualified type, the copy/move operation
// can be omitted by constructing the temporary object
// directly into the target of the omitted copy/move
//
// Note that the other three bullets are handled elsewhere. Copy
// elision for return statements and throw expressions are handled as part
// of constructor initialization, while copy elision for exception handlers
// is handled by the run-time.
//
// FIXME: If the function parameter is not the same type as the temporary, we
// should still be able to elide the copy, but we don't have a way to
// represent in the AST how much should be elided in this case.
bool Elidable =
CurInitExpr->isTemporaryObject(S.Context, Class) &&
S.Context.hasSameUnqualifiedType(
Best->Function->getParamDecl(0)->getType().getNonReferenceType(),
CurInitExpr->getType());
// Actually perform the constructor call.
CurInit = S.BuildCXXConstructExpr(Loc, T, Best->FoundDecl, Constructor,
Elidable,
ConstructorArgs,
HadMultipleCandidates,
/*ListInit*/ false,
/*StdInitListInit*/ false,
/*ZeroInit*/ false,
CXXConstructExpr::CK_Complete,
SourceRange());
// If we're supposed to bind temporaries, do so.
if (!CurInit.isInvalid() && shouldBindAsTemporary(Entity))
CurInit = S.MaybeBindToTemporary(CurInit.getAs<Expr>());
return CurInit;
}
/// Check whether elidable copy construction for binding a reference to
/// a temporary would have succeeded if we were building in C++98 mode, for
/// -Wc++98-compat.
static void CheckCXX98CompatAccessibleCopy(Sema &S,
const InitializedEntity &Entity,
Expr *CurInitExpr) {
assert(S.getLangOpts().CPlusPlus11);
const RecordType *Record = CurInitExpr->getType()->getAs<RecordType>();
if (!Record)
return;
SourceLocation Loc = getInitializationLoc(Entity, CurInitExpr);
if (S.Diags.isIgnored(diag::warn_cxx98_compat_temp_copy, Loc))
return;
// Find constructors which would have been considered.
OverloadCandidateSet CandidateSet(Loc, OverloadCandidateSet::CSK_Normal);
DeclContext::lookup_result Ctors =
S.LookupConstructors(cast<CXXRecordDecl>(Record->getDecl()));
// Perform overload resolution.
OverloadCandidateSet::iterator Best;
OverloadingResult OR = ResolveConstructorOverload(
S, Loc, CurInitExpr, CandidateSet, CurInitExpr->getType(), Ctors, Best,
/*CopyInitializing=*/false, /*AllowExplicit=*/true,
/*OnlyListConstructors=*/false, /*IsListInit=*/false,
/*SecondStepOfCopyInit=*/true);
PartialDiagnostic Diag = S.PDiag(diag::warn_cxx98_compat_temp_copy)
<< OR << (int)Entity.getKind() << CurInitExpr->getType()
<< CurInitExpr->getSourceRange();
switch (OR) {
case OR_Success:
S.CheckConstructorAccess(Loc, cast<CXXConstructorDecl>(Best->Function),
Best->FoundDecl, Entity, Diag);
// FIXME: Check default arguments as far as that's possible.
break;
case OR_No_Viable_Function:
CandidateSet.NoteCandidates(PartialDiagnosticAt(Loc, Diag), S,
OCD_AllCandidates, CurInitExpr);
break;
case OR_Ambiguous:
CandidateSet.NoteCandidates(PartialDiagnosticAt(Loc, Diag), S,
OCD_AmbiguousCandidates, CurInitExpr);
break;
case OR_Deleted:
S.Diag(Loc, Diag);
S.NoteDeletedFunction(Best->Function);
break;
}
}
void InitializationSequence::PrintInitLocationNote(Sema &S,
const InitializedEntity &Entity) {
if (Entity.isParamOrTemplateParamKind() && Entity.getDecl()) {
if (Entity.getDecl()->getLocation().isInvalid())
return;
if (Entity.getDecl()->getDeclName())
S.Diag(Entity.getDecl()->getLocation(), diag::note_parameter_named_here)
<< Entity.getDecl()->getDeclName();
else
S.Diag(Entity.getDecl()->getLocation(), diag::note_parameter_here);
}
else if (Entity.getKind() == InitializedEntity::EK_RelatedResult &&
Entity.getMethodDecl())
S.Diag(Entity.getMethodDecl()->getLocation(),
diag::note_method_return_type_change)
<< Entity.getMethodDecl()->getDeclName();
}
/// Returns true if the parameters describe a constructor initialization of
/// an explicit temporary object, e.g. "Point(x, y)".
static bool isExplicitTemporary(const InitializedEntity &Entity,
const InitializationKind &Kind,
unsigned NumArgs) {
switch (Entity.getKind()) {
case InitializedEntity::EK_Temporary:
case InitializedEntity::EK_CompoundLiteralInit:
case InitializedEntity::EK_RelatedResult:
break;
default:
return false;
}
switch (Kind.getKind()) {
case InitializationKind::IK_DirectList:
return true;
// FIXME: Hack to work around cast weirdness.
case InitializationKind::IK_Direct:
case InitializationKind::IK_Value:
return NumArgs != 1;
default:
return false;
}
}
static ExprResult
PerformConstructorInitialization(Sema &S,
const InitializedEntity &Entity,
const InitializationKind &Kind,
MultiExprArg Args,
const InitializationSequence::Step& Step,
bool &ConstructorInitRequiresZeroInit,
bool IsListInitialization,
bool IsStdInitListInitialization,
SourceLocation LBraceLoc,
SourceLocation RBraceLoc) {
unsigned NumArgs = Args.size();
CXXConstructorDecl *Constructor
= cast<CXXConstructorDecl>(Step.Function.Function);
bool HadMultipleCandidates = Step.Function.HadMultipleCandidates;
// Build a call to the selected constructor.
SmallVector<Expr*, 8> ConstructorArgs;
SourceLocation Loc = (Kind.isCopyInit() && Kind.getEqualLoc().isValid())
? Kind.getEqualLoc()
: Kind.getLocation();
if (Kind.getKind() == InitializationKind::IK_Default) {
// Force even a trivial, implicit default constructor to be
// semantically checked. We do this explicitly because we don't build
// the definition for completely trivial constructors.
assert(Constructor->getParent() && "No parent class for constructor.");
if (Constructor->isDefaulted() && Constructor->isDefaultConstructor() &&
Constructor->isTrivial() && !Constructor->isUsed(false)) {
S.runWithSufficientStackSpace(Loc, [&] {
S.DefineImplicitDefaultConstructor(Loc, Constructor);
});
}
}
ExprResult CurInit((Expr *)nullptr);
// C++ [over.match.copy]p1:
// - When initializing a temporary to be bound to the first parameter
// of a constructor that takes a reference to possibly cv-qualified
// T as its first argument, called with a single argument in the
// context of direct-initialization, explicit conversion functions
// are also considered.
bool AllowExplicitConv =
Kind.AllowExplicit() && !Kind.isCopyInit() && Args.size() == 1 &&
hasCopyOrMoveCtorParam(S.Context,
getConstructorInfo(Step.Function.FoundDecl));
// Determine the arguments required to actually perform the constructor
// call.
if (S.CompleteConstructorCall(Constructor, Args,
Loc, ConstructorArgs,
AllowExplicitConv,
IsListInitialization))
return ExprError();
if (isExplicitTemporary(Entity, Kind, NumArgs)) {
// An explicitly-constructed temporary, e.g., X(1, 2).
if (S.DiagnoseUseOfDecl(Constructor, Loc))
return ExprError();
TypeSourceInfo *TSInfo = Entity.getTypeSourceInfo();
if (!TSInfo)
TSInfo = S.Context.getTrivialTypeSourceInfo(Entity.getType(), Loc);
SourceRange ParenOrBraceRange =
(Kind.getKind() == InitializationKind::IK_DirectList)
? SourceRange(LBraceLoc, RBraceLoc)
: Kind.getParenOrBraceRange();
if (auto *Shadow = dyn_cast<ConstructorUsingShadowDecl>(
Step.Function.FoundDecl.getDecl())) {
Constructor = S.findInheritingConstructor(Loc, Constructor, Shadow);
if (S.DiagnoseUseOfDecl(Constructor, Loc))
return ExprError();
}
S.MarkFunctionReferenced(Loc, Constructor);
CurInit = S.CheckForImmediateInvocation(
CXXTemporaryObjectExpr::Create(
S.Context, Constructor,
Entity.getType().getNonLValueExprType(S.Context), TSInfo,
ConstructorArgs, ParenOrBraceRange, HadMultipleCandidates,
IsListInitialization, IsStdInitListInitialization,
ConstructorInitRequiresZeroInit),
Constructor);
} else {
CXXConstructExpr::ConstructionKind ConstructKind =
CXXConstructExpr::CK_Complete;
if (Entity.getKind() == InitializedEntity::EK_Base) {
ConstructKind = Entity.getBaseSpecifier()->isVirtual() ?
CXXConstructExpr::CK_VirtualBase :
CXXConstructExpr::CK_NonVirtualBase;
} else if (Entity.getKind() == InitializedEntity::EK_Delegating) {
ConstructKind = CXXConstructExpr::CK_Delegating;
}
// Only get the parenthesis or brace range if it is a list initialization or
// direct construction.
SourceRange ParenOrBraceRange;
if (IsListInitialization)
ParenOrBraceRange = SourceRange(LBraceLoc, RBraceLoc);
else if (Kind.getKind() == InitializationKind::IK_Direct)
ParenOrBraceRange = Kind.getParenOrBraceRange();
// If the entity allows NRVO, mark the construction as elidable
// unconditionally.
if (Entity.allowsNRVO())
CurInit = S.BuildCXXConstructExpr(Loc, Step.Type,
Step.Function.FoundDecl,
Constructor, /*Elidable=*/true,
ConstructorArgs,
HadMultipleCandidates,
IsListInitialization,
IsStdInitListInitialization,
ConstructorInitRequiresZeroInit,
ConstructKind,
ParenOrBraceRange);
else
CurInit = S.BuildCXXConstructExpr(Loc, Step.Type,
Step.Function.FoundDecl,
Constructor,
ConstructorArgs,
HadMultipleCandidates,
IsListInitialization,
IsStdInitListInitialization,
ConstructorInitRequiresZeroInit,
ConstructKind,
ParenOrBraceRange);
}
if (CurInit.isInvalid())
return ExprError();
// Only check access if all of that succeeded.
S.CheckConstructorAccess(Loc, Constructor, Step.Function.FoundDecl, Entity);
if (S.DiagnoseUseOfDecl(Step.Function.FoundDecl, Loc))
return ExprError();
if (const ArrayType *AT = S.Context.getAsArrayType(Entity.getType()))
if (checkDestructorReference(S.Context.getBaseElementType(AT), Loc, S))
return ExprError();
if (shouldBindAsTemporary(Entity))
CurInit = S.MaybeBindToTemporary(CurInit.get());
return CurInit;
}
namespace {
enum LifetimeKind {
/// The lifetime of a temporary bound to this entity ends at the end of the
/// full-expression, and that's (probably) fine.
LK_FullExpression,
/// The lifetime of a temporary bound to this entity is extended to the
/// lifeitme of the entity itself.
LK_Extended,
/// The lifetime of a temporary bound to this entity probably ends too soon,
/// because the entity is allocated in a new-expression.
LK_New,
/// The lifetime of a temporary bound to this entity ends too soon, because
/// the entity is a return object.
LK_Return,
/// The lifetime of a temporary bound to this entity ends too soon, because
/// the entity is the result of a statement expression.
LK_StmtExprResult,
/// This is a mem-initializer: if it would extend a temporary (other than via
/// a default member initializer), the program is ill-formed.
LK_MemInitializer,
};
using LifetimeResult =
llvm::PointerIntPair<const InitializedEntity *, 3, LifetimeKind>;
}
/// Determine the declaration which an initialized entity ultimately refers to,
/// for the purpose of lifetime-extending a temporary bound to a reference in
/// the initialization of \p Entity.
static LifetimeResult getEntityLifetime(
const InitializedEntity *Entity,
const InitializedEntity *InitField = nullptr) {
// C++11 [class.temporary]p5:
switch (Entity->getKind()) {
case InitializedEntity::EK_Variable:
// The temporary [...] persists for the lifetime of the reference
return {Entity, LK_Extended};
case InitializedEntity::EK_Member:
// For subobjects, we look at the complete object.
if (Entity->getParent())
return getEntityLifetime(Entity->getParent(), Entity);
// except:
// C++17 [class.base.init]p8:
// A temporary expression bound to a reference member in a
// mem-initializer is ill-formed.
// C++17 [class.base.init]p11:
// A temporary expression bound to a reference member from a
// default member initializer is ill-formed.
//
// The context of p11 and its example suggest that it's only the use of a
// default member initializer from a constructor that makes the program
// ill-formed, not its mere existence, and that it can even be used by
// aggregate initialization.
return {Entity, Entity->isDefaultMemberInitializer() ? LK_Extended
: LK_MemInitializer};
case InitializedEntity::EK_Binding:
// Per [dcl.decomp]p3, the binding is treated as a variable of reference
// type.
return {Entity, LK_Extended};
case InitializedEntity::EK_Parameter:
case InitializedEntity::EK_Parameter_CF_Audited:
// -- A temporary bound to a reference parameter in a function call
// persists until the completion of the full-expression containing
// the call.
return {nullptr, LK_FullExpression};
case InitializedEntity::EK_TemplateParameter:
// FIXME: This will always be ill-formed; should we eagerly diagnose it here?
return {nullptr, LK_FullExpression};
case InitializedEntity::EK_Result:
// -- The lifetime of a temporary bound to the returned value in a
// function return statement is not extended; the temporary is
// destroyed at the end of the full-expression in the return statement.
return {nullptr, LK_Return};
case InitializedEntity::EK_StmtExprResult:
// FIXME: Should we lifetime-extend through the result of a statement
// expression?
return {nullptr, LK_StmtExprResult};
case InitializedEntity::EK_New:
// -- A temporary bound to a reference in a new-initializer persists
// until the completion of the full-expression containing the
// new-initializer.
return {nullptr, LK_New};
case InitializedEntity::EK_Temporary:
case InitializedEntity::EK_CompoundLiteralInit:
case InitializedEntity::EK_RelatedResult:
// We don't yet know the storage duration of the surrounding temporary.
// Assume it's got full-expression duration for now, it will patch up our
// storage duration if that's not correct.
return {nullptr, LK_FullExpression};
case InitializedEntity::EK_ArrayElement:
// For subobjects, we look at the complete object.
return getEntityLifetime(Entity->getParent(), InitField);
case InitializedEntity::EK_Base:
// For subobjects, we look at the complete object.
if (Entity->getParent())
return getEntityLifetime(Entity->getParent(), InitField);
return {InitField, LK_MemInitializer};
case InitializedEntity::EK_Delegating:
// We can reach this case for aggregate initialization in a constructor:
// struct A { int &&r; };
// struct B : A { B() : A{0} {} };
// In this case, use the outermost field decl as the context.
return {InitField, LK_MemInitializer};
case InitializedEntity::EK_BlockElement:
case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
case InitializedEntity::EK_LambdaCapture:
case InitializedEntity::EK_VectorElement:
case InitializedEntity::EK_ComplexElement:
return {nullptr, LK_FullExpression};
case InitializedEntity::EK_Exception:
// FIXME: Can we diagnose lifetime problems with exceptions?
return {nullptr, LK_FullExpression};
}
llvm_unreachable("unknown entity kind");
}
namespace {
enum ReferenceKind {
/// Lifetime would be extended by a reference binding to a temporary.
RK_ReferenceBinding,
/// Lifetime would be extended by a std::initializer_list object binding to
/// its backing array.
RK_StdInitializerList,
};
/// A temporary or local variable. This will be one of:
/// * A MaterializeTemporaryExpr.
/// * A DeclRefExpr whose declaration is a local.
/// * An AddrLabelExpr.
/// * A BlockExpr for a block with captures.
using Local = Expr*;
/// Expressions we stepped over when looking for the local state. Any steps
/// that would inhibit lifetime extension or take us out of subexpressions of
/// the initializer are included.
struct IndirectLocalPathEntry {
enum EntryKind {
DefaultInit,
AddressOf,
VarInit,
LValToRVal,
LifetimeBoundCall,
TemporaryCopy,
LambdaCaptureInit,
GslReferenceInit,
GslPointerInit
} Kind;
Expr *E;
union {
const Decl *D = nullptr;
const LambdaCapture *Capture;
};
IndirectLocalPathEntry() {}
IndirectLocalPathEntry(EntryKind K, Expr *E) : Kind(K), E(E) {}
IndirectLocalPathEntry(EntryKind K, Expr *E, const Decl *D)
: Kind(K), E(E), D(D) {}
IndirectLocalPathEntry(EntryKind K, Expr *E, const LambdaCapture *Capture)
: Kind(K), E(E), Capture(Capture) {}
};
using IndirectLocalPath = llvm::SmallVectorImpl<IndirectLocalPathEntry>;
struct RevertToOldSizeRAII {
IndirectLocalPath &Path;
unsigned OldSize = Path.size();
RevertToOldSizeRAII(IndirectLocalPath &Path) : Path(Path) {}
~RevertToOldSizeRAII() { Path.resize(OldSize); }
};
using LocalVisitor = llvm::function_ref<bool(IndirectLocalPath &Path, Local L,
ReferenceKind RK)>;
}
static bool isVarOnPath(IndirectLocalPath &Path, VarDecl *VD) {
for (auto E : Path)
if (E.Kind == IndirectLocalPathEntry::VarInit && E.D == VD)
return true;
return false;
}
static bool pathContainsInit(IndirectLocalPath &Path) {
return llvm::any_of(Path, [=](IndirectLocalPathEntry E) {
return E.Kind == IndirectLocalPathEntry::DefaultInit ||
E.Kind == IndirectLocalPathEntry::VarInit;
});
}
static void visitLocalsRetainedByInitializer(IndirectLocalPath &Path,
Expr *Init, LocalVisitor Visit,
bool RevisitSubinits,
bool EnableLifetimeWarnings);
static void visitLocalsRetainedByReferenceBinding(IndirectLocalPath &Path,
Expr *Init, ReferenceKind RK,
LocalVisitor Visit,
bool EnableLifetimeWarnings);
template <typename T> static bool isRecordWithAttr(QualType Type) {
if (auto *RD = Type->getAsCXXRecordDecl())
return RD->hasAttr<T>();
return false;
}
// Decl::isInStdNamespace will return false for iterators in some STL
// implementations due to them being defined in a namespace outside of the std
// namespace.
static bool isInStlNamespace(const Decl *D) {
const DeclContext *DC = D->getDeclContext();
if (!DC)
return false;
if (const auto *ND = dyn_cast<NamespaceDecl>(DC))
if (const IdentifierInfo *II = ND->getIdentifier()) {
StringRef Name = II->getName();
if (Name.size() >= 2 && Name.front() == '_' &&
(Name[1] == '_' || isUppercase(Name[1])))
return true;
}
return DC->isStdNamespace();
}
static bool shouldTrackImplicitObjectArg(const CXXMethodDecl *Callee) {
if (auto *Conv = dyn_cast_or_null<CXXConversionDecl>(Callee))
if (isRecordWithAttr<PointerAttr>(Conv->getConversionType()))
return true;
if (!isInStlNamespace(Callee->getParent()))
return false;
if (!isRecordWithAttr<PointerAttr>(Callee->getThisObjectType()) &&
!isRecordWithAttr<OwnerAttr>(Callee->getThisObjectType()))
return false;
if (Callee->getReturnType()->isPointerType() ||
isRecordWithAttr<PointerAttr>(Callee->getReturnType())) {
if (!Callee->getIdentifier())
return false;
return llvm::StringSwitch<bool>(Callee->getName())
.Cases("begin", "rbegin", "cbegin", "crbegin", true)
.Cases("end", "rend", "cend", "crend", true)
.Cases("c_str", "data", "get", true)
// Map and set types.
.Cases("find", "equal_range", "lower_bound", "upper_bound", true)
.Default(false);
} else if (Callee->getReturnType()->isReferenceType()) {
if (!Callee->getIdentifier()) {
auto OO = Callee->getOverloadedOperator();
return OO == OverloadedOperatorKind::OO_Subscript ||
OO == OverloadedOperatorKind::OO_Star;
}
return llvm::StringSwitch<bool>(Callee->getName())
.Cases("front", "back", "at", "top", "value", true)
.Default(false);
}
return false;
}
static bool shouldTrackFirstArgument(const FunctionDecl *FD) {
if (!FD->getIdentifier() || FD->getNumParams() != 1)
return false;
const auto *RD = FD->getParamDecl(0)->getType()->getPointeeCXXRecordDecl();
if (!FD->isInStdNamespace() || !RD || !RD->isInStdNamespace())
return false;
if (!isRecordWithAttr<PointerAttr>(QualType(RD->getTypeForDecl(), 0)) &&
!isRecordWithAttr<OwnerAttr>(QualType(RD->getTypeForDecl(), 0)))
return false;
if (FD->getReturnType()->isPointerType() ||
isRecordWithAttr<PointerAttr>(FD->getReturnType())) {
return llvm::StringSwitch<bool>(FD->getName())
.Cases("begin", "rbegin", "cbegin", "crbegin", true)
.Cases("end", "rend", "cend", "crend", true)
.Case("data", true)
.Default(false);
} else if (FD->getReturnType()->isReferenceType()) {
return llvm::StringSwitch<bool>(FD->getName())
.Cases("get", "any_cast", true)
.Default(false);
}
return false;
}
static void handleGslAnnotatedTypes(IndirectLocalPath &Path, Expr *Call,
LocalVisitor Visit) {
auto VisitPointerArg = [&](const Decl *D, Expr *Arg, bool Value) {
// We are not interested in the temporary base objects of gsl Pointers:
// Temp().ptr; // Here ptr might not dangle.
if (isa<MemberExpr>(Arg->IgnoreImpCasts()))
return;
// Once we initialized a value with a reference, it can no longer dangle.
if (!Value) {
for (auto It = Path.rbegin(), End = Path.rend(); It != End; ++It) {
if (It->Kind == IndirectLocalPathEntry::GslReferenceInit)
continue;
if (It->Kind == IndirectLocalPathEntry::GslPointerInit)
return;
break;
}
}
Path.push_back({Value ? IndirectLocalPathEntry::GslPointerInit
: IndirectLocalPathEntry::GslReferenceInit,
Arg, D});
if (Arg->isGLValue())
visitLocalsRetainedByReferenceBinding(Path, Arg, RK_ReferenceBinding,
Visit,
/*EnableLifetimeWarnings=*/true);
else
visitLocalsRetainedByInitializer(Path, Arg, Visit, true,
/*EnableLifetimeWarnings=*/true);
Path.pop_back();
};
if (auto *MCE = dyn_cast<CXXMemberCallExpr>(Call)) {
const auto *MD = cast_or_null<CXXMethodDecl>(MCE->getDirectCallee());
if (MD && shouldTrackImplicitObjectArg(MD))
VisitPointerArg(MD, MCE->getImplicitObjectArgument(),
!MD->getReturnType()->isReferenceType());
return;
} else if (auto *OCE = dyn_cast<CXXOperatorCallExpr>(Call)) {
FunctionDecl *Callee = OCE->getDirectCallee();
if (Callee && Callee->isCXXInstanceMember() &&
shouldTrackImplicitObjectArg(cast<CXXMethodDecl>(Callee)))
VisitPointerArg(Callee, OCE->getArg(0),
!Callee->getReturnType()->isReferenceType());
return;
} else if (auto *CE = dyn_cast<CallExpr>(Call)) {
FunctionDecl *Callee = CE->getDirectCallee();
if (Callee && shouldTrackFirstArgument(Callee))
VisitPointerArg(Callee, CE->getArg(0),
!Callee->getReturnType()->isReferenceType());
return;
}
if (auto *CCE = dyn_cast<CXXConstructExpr>(Call)) {
const auto *Ctor = CCE->getConstructor();
const CXXRecordDecl *RD = Ctor->getParent();
if (CCE->getNumArgs() > 0 && RD->hasAttr<PointerAttr>())
VisitPointerArg(Ctor->getParamDecl(0), CCE->getArgs()[0], true);
}
}
static bool implicitObjectParamIsLifetimeBound(const FunctionDecl *FD) {
const TypeSourceInfo *TSI = FD->getTypeSourceInfo();
if (!TSI)
return false;
// Don't declare this variable in the second operand of the for-statement;
// GCC miscompiles that by ending its lifetime before evaluating the
// third operand. See gcc.gnu.org/PR86769.
AttributedTypeLoc ATL;
for (TypeLoc TL = TSI->getTypeLoc();
(ATL = TL.getAsAdjusted<AttributedTypeLoc>());
TL = ATL.getModifiedLoc()) {
if (ATL.getAttrAs<LifetimeBoundAttr>())
return true;
}
// Assume that all assignment operators with a "normal" return type return
// *this, that is, an lvalue reference that is the same type as the implicit
// object parameter (or the LHS for a non-member operator$=).
OverloadedOperatorKind OO = FD->getDeclName().getCXXOverloadedOperator();
if (OO == OO_Equal || isCompoundAssignmentOperator(OO)) {
QualType RetT = FD->getReturnType();
if (RetT->isLValueReferenceType()) {
ASTContext &Ctx = FD->getASTContext();
QualType LHST;
auto *MD = dyn_cast<CXXMethodDecl>(FD);
if (MD && MD->isCXXInstanceMember())
LHST = Ctx.getLValueReferenceType(MD->getThisObjectType());
else
LHST = MD->getParamDecl(0)->getType();
if (Ctx.hasSameType(RetT, LHST))
return true;
}
}
return false;
}
static void visitLifetimeBoundArguments(IndirectLocalPath &Path, Expr *Call,
LocalVisitor Visit) {
const FunctionDecl *Callee;
ArrayRef<Expr*> Args;
if (auto *CE = dyn_cast<CallExpr>(Call)) {
Callee = CE->getDirectCallee();
Args = llvm::makeArrayRef(CE->getArgs(), CE->getNumArgs());
} else {
auto *CCE = cast<CXXConstructExpr>(Call);
Callee = CCE->getConstructor();
Args = llvm::makeArrayRef(CCE->getArgs(), CCE->getNumArgs());
}
if (!Callee)
return;
Expr *ObjectArg = nullptr;
if (isa<CXXOperatorCallExpr>(Call) && Callee->isCXXInstanceMember()) {
ObjectArg = Args[0];
Args = Args.slice(1);
} else if (auto *MCE = dyn_cast<CXXMemberCallExpr>(Call)) {
ObjectArg = MCE->getImplicitObjectArgument();
}
auto VisitLifetimeBoundArg = [&](const Decl *D, Expr *Arg) {
Path.push_back({IndirectLocalPathEntry::LifetimeBoundCall, Arg, D});
if (Arg->isGLValue())
visitLocalsRetainedByReferenceBinding(Path, Arg, RK_ReferenceBinding,
Visit,
/*EnableLifetimeWarnings=*/false);
else
visitLocalsRetainedByInitializer(Path, Arg, Visit, true,
/*EnableLifetimeWarnings=*/false);
Path.pop_back();
};
if (ObjectArg && implicitObjectParamIsLifetimeBound(Callee))
VisitLifetimeBoundArg(Callee, ObjectArg);
for (unsigned I = 0,
N = std::min<unsigned>(Callee->getNumParams(), Args.size());
I != N; ++I) {
if (Callee->getParamDecl(I)->hasAttr<LifetimeBoundAttr>())
VisitLifetimeBoundArg(Callee->getParamDecl(I), Args[I]);
}
}
/// Visit the locals that would be reachable through a reference bound to the
/// glvalue expression \c Init.
static void visitLocalsRetainedByReferenceBinding(IndirectLocalPath &Path,
Expr *Init, ReferenceKind RK,
LocalVisitor Visit,
bool EnableLifetimeWarnings) {
RevertToOldSizeRAII RAII(Path);
// Walk past any constructs which we can lifetime-extend across.
Expr *Old;
do {
Old = Init;
if (auto *FE = dyn_cast<FullExpr>(Init))
Init = FE->getSubExpr();
if (InitListExpr *ILE = dyn_cast<InitListExpr>(Init)) {
// If this is just redundant braces around an initializer, step over it.
if (ILE->isTransparent())
Init = ILE->getInit(0);
}
// Step over any subobject adjustments; we may have a materialized
// temporary inside them.
Init = const_cast<Expr *>(Init->skipRValueSubobjectAdjustments());
// Per current approach for DR1376, look through casts to reference type
// when performing lifetime extension.
if (CastExpr *CE = dyn_cast<CastExpr>(Init))
if (CE->getSubExpr()->isGLValue())
Init = CE->getSubExpr();
// Per the current approach for DR1299, look through array element access
// on array glvalues when performing lifetime extension.
if (auto *ASE = dyn_cast<ArraySubscriptExpr>(Init)) {
Init = ASE->getBase();
auto *ICE = dyn_cast<ImplicitCastExpr>(Init);
if (ICE && ICE->getCastKind() == CK_ArrayToPointerDecay)
Init = ICE->getSubExpr();
else
// We can't lifetime extend through this but we might still find some
// retained temporaries.
return visitLocalsRetainedByInitializer(Path, Init, Visit, true,
EnableLifetimeWarnings);
}
// Step into CXXDefaultInitExprs so we can diagnose cases where a
// constructor inherits one as an implicit mem-initializer.
if (auto *DIE = dyn_cast<CXXDefaultInitExpr>(Init)) {
Path.push_back(
{IndirectLocalPathEntry::DefaultInit, DIE, DIE->getField()});
Init = DIE->getExpr();
}
} while (Init != Old);
if (auto *MTE = dyn_cast<MaterializeTemporaryExpr>(Init)) {
if (Visit(Path, Local(MTE), RK))
visitLocalsRetainedByInitializer(Path, MTE->getSubExpr(), Visit, true,
EnableLifetimeWarnings);
}
if (isa<CallExpr>(Init)) {
if (EnableLifetimeWarnings)
handleGslAnnotatedTypes(Path, Init, Visit);
return visitLifetimeBoundArguments(Path, Init, Visit);
}
switch (Init->getStmtClass()) {
case Stmt::DeclRefExprClass: {
// If we find the name of a local non-reference parameter, we could have a
// lifetime problem.
auto *DRE = cast<DeclRefExpr>(Init);
auto *VD = dyn_cast<VarDecl>(DRE->getDecl());
if (VD && VD->hasLocalStorage() &&
!DRE->refersToEnclosingVariableOrCapture()) {
if (!VD->getType()->isReferenceType()) {
Visit(Path, Local(DRE), RK);
} else if (isa<ParmVarDecl>(DRE->getDecl())) {
// The lifetime of a reference parameter is unknown; assume it's OK
// for now.
break;
} else if (VD->getInit() && !isVarOnPath(Path, VD)) {
Path.push_back({IndirectLocalPathEntry::VarInit, DRE, VD});
visitLocalsRetainedByReferenceBinding(Path, VD->getInit(),
RK_ReferenceBinding, Visit,
EnableLifetimeWarnings);
}
}
break;
}
case Stmt::UnaryOperatorClass: {
// The only unary operator that make sense to handle here
// is Deref. All others don't resolve to a "name." This includes
// handling all sorts of rvalues passed to a unary operator.
const UnaryOperator *U = cast<UnaryOperator>(Init);
if (U->getOpcode() == UO_Deref)
visitLocalsRetainedByInitializer(Path, U->getSubExpr(), Visit, true,
EnableLifetimeWarnings);
break;
}
case Stmt::OMPArraySectionExprClass: {
visitLocalsRetainedByInitializer(Path,
cast<OMPArraySectionExpr>(Init)->getBase(),
Visit, true, EnableLifetimeWarnings);
break;
}
case Stmt::ConditionalOperatorClass:
case Stmt::BinaryConditionalOperatorClass: {
auto *C = cast<AbstractConditionalOperator>(Init);
if (!C->getTrueExpr()->getType()->isVoidType())
visitLocalsRetainedByReferenceBinding(Path, C->getTrueExpr(), RK, Visit,
EnableLifetimeWarnings);
if (!C->getFalseExpr()->getType()->isVoidType())
visitLocalsRetainedByReferenceBinding(Path, C->getFalseExpr(), RK, Visit,
EnableLifetimeWarnings);
break;
}
// FIXME: Visit the left-hand side of an -> or ->*.
default:
break;
}
}
/// Visit the locals that would be reachable through an object initialized by
/// the prvalue expression \c Init.
static void visitLocalsRetainedByInitializer(IndirectLocalPath &Path,
Expr *Init, LocalVisitor Visit,
bool RevisitSubinits,
bool EnableLifetimeWarnings) {
RevertToOldSizeRAII RAII(Path);
Expr *Old;
do {
Old = Init;
// Step into CXXDefaultInitExprs so we can diagnose cases where a
// constructor inherits one as an implicit mem-initializer.
if (auto *DIE = dyn_cast<CXXDefaultInitExpr>(Init)) {
Path.push_back({IndirectLocalPathEntry::DefaultInit, DIE, DIE->getField()});
Init = DIE->getExpr();
}
if (auto *FE = dyn_cast<FullExpr>(Init))
Init = FE->getSubExpr();
// Dig out the expression which constructs the extended temporary.
Init = const_cast<Expr *>(Init->skipRValueSubobjectAdjustments());
if (CXXBindTemporaryExpr *BTE = dyn_cast<CXXBindTemporaryExpr>(Init))
Init = BTE->getSubExpr();
Init = Init->IgnoreParens();
// Step over value-preserving rvalue casts.
if (auto *CE = dyn_cast<CastExpr>(Init)) {
switch (CE->getCastKind()) {
case CK_LValueToRValue:
// If we can match the lvalue to a const object, we can look at its
// initializer.
Path.push_back({IndirectLocalPathEntry::LValToRVal, CE});
return visitLocalsRetainedByReferenceBinding(
Path, Init, RK_ReferenceBinding,
[&](IndirectLocalPath &Path, Local L, ReferenceKind RK) -> bool {
if (auto *DRE = dyn_cast<DeclRefExpr>(L)) {
auto *VD = dyn_cast<VarDecl>(DRE->getDecl());
if (VD && VD->getType().isConstQualified() && VD->getInit() &&
!isVarOnPath(Path, VD)) {
Path.push_back({IndirectLocalPathEntry::VarInit, DRE, VD});
visitLocalsRetainedByInitializer(Path, VD->getInit(), Visit, true,
EnableLifetimeWarnings);
}
} else if (auto *MTE = dyn_cast<MaterializeTemporaryExpr>(L)) {
if (MTE->getType().isConstQualified())
visitLocalsRetainedByInitializer(Path, MTE->getSubExpr(), Visit,
true, EnableLifetimeWarnings);
}
return false;
}, EnableLifetimeWarnings);
// We assume that objects can be retained by pointers cast to integers,
// but not if the integer is cast to floating-point type or to _Complex.
// We assume that casts to 'bool' do not preserve enough information to
// retain a local object.
case CK_NoOp:
case CK_BitCast:
case CK_BaseToDerived:
case CK_DerivedToBase:
case CK_UncheckedDerivedToBase:
case CK_Dynamic:
case CK_ToUnion:
case CK_UserDefinedConversion:
case CK_ConstructorConversion:
case CK_IntegralToPointer:
case CK_PointerToIntegral:
case CK_VectorSplat:
case CK_IntegralCast:
case CK_CPointerToObjCPointerCast:
case CK_BlockPointerToObjCPointerCast:
case CK_AnyPointerToBlockPointerCast:
case CK_AddressSpaceConversion:
break;
case CK_ArrayToPointerDecay:
// Model array-to-pointer decay as taking the address of the array
// lvalue.
Path.push_back({IndirectLocalPathEntry::AddressOf, CE});
return visitLocalsRetainedByReferenceBinding(Path, CE->getSubExpr(),
RK_ReferenceBinding, Visit,
EnableLifetimeWarnings);
default:
return;
}
Init = CE->getSubExpr();
}
} while (Old != Init);
// C++17 [dcl.init.list]p6:
// initializing an initializer_list object from the array extends the
// lifetime of the array exactly like binding a reference to a temporary.
if (auto *ILE = dyn_cast<CXXStdInitializerListExpr>(Init))
return visitLocalsRetainedByReferenceBinding(Path, ILE->getSubExpr(),
RK_StdInitializerList, Visit,
EnableLifetimeWarnings);
if (InitListExpr *ILE = dyn_cast<InitListExpr>(Init)) {
// We already visited the elements of this initializer list while
// performing the initialization. Don't visit them again unless we've
// changed the lifetime of the initialized entity.
if (!RevisitSubinits)
return;
if (ILE->isTransparent())
return visitLocalsRetainedByInitializer(Path, ILE->getInit(0), Visit,
RevisitSubinits,
EnableLifetimeWarnings);
if (ILE->getType()->isArrayType()) {
for (unsigned I = 0, N = ILE->getNumInits(); I != N; ++I)
visitLocalsRetainedByInitializer(Path, ILE->getInit(I), Visit,
RevisitSubinits,
EnableLifetimeWarnings);
return;
}
if (CXXRecordDecl *RD = ILE->getType()->getAsCXXRecordDecl()) {
assert(RD->isAggregate() && "aggregate init on non-aggregate");
// If we lifetime-extend a braced initializer which is initializing an
// aggregate, and that aggregate contains reference members which are
// bound to temporaries, those temporaries are also lifetime-extended.
if (RD->isUnion() && ILE->getInitializedFieldInUnion() &&
ILE->getInitializedFieldInUnion()->getType()->isReferenceType())
visitLocalsRetainedByReferenceBinding(Path, ILE->getInit(0),
RK_ReferenceBinding, Visit,
EnableLifetimeWarnings);
else {
unsigned Index = 0;
for (; Index < RD->getNumBases() && Index < ILE->getNumInits(); ++Index)
visitLocalsRetainedByInitializer(Path, ILE->getInit(Index), Visit,
RevisitSubinits,
EnableLifetimeWarnings);
for (const auto *I : RD->fields()) {
if (Index >= ILE->getNumInits())
break;
if (I->isUnnamedBitfield())
continue;
Expr *SubInit = ILE->getInit(Index);
if (I->getType()->isReferenceType())
visitLocalsRetainedByReferenceBinding(Path, SubInit,
RK_ReferenceBinding, Visit,
EnableLifetimeWarnings);
else
// This might be either aggregate-initialization of a member or
// initialization of a std::initializer_list object. Regardless,
// we should recursively lifetime-extend that initializer.
visitLocalsRetainedByInitializer(Path, SubInit, Visit,
RevisitSubinits,
EnableLifetimeWarnings);
++Index;
}
}
}
return;
}
// The lifetime of an init-capture is that of the closure object constructed
// by a lambda-expression.
if (auto *LE = dyn_cast<LambdaExpr>(Init)) {
LambdaExpr::capture_iterator CapI = LE->capture_begin();
for (Expr *E : LE->capture_inits()) {
assert(CapI != LE->capture_end());
const LambdaCapture &Cap = *CapI++;
if (!E)
continue;
if (Cap.capturesVariable())
Path.push_back({IndirectLocalPathEntry::LambdaCaptureInit, E, &Cap});
if (E->isGLValue())
visitLocalsRetainedByReferenceBinding(Path, E, RK_ReferenceBinding,
Visit, EnableLifetimeWarnings);
else
visitLocalsRetainedByInitializer(Path, E, Visit, true,
EnableLifetimeWarnings);
if (Cap.capturesVariable())
Path.pop_back();
}
}
// Assume that a copy or move from a temporary references the same objects
// that the temporary does.
if (auto *CCE = dyn_cast<CXXConstructExpr>(Init)) {
if (CCE->getConstructor()->isCopyOrMoveConstructor()) {
if (auto *MTE = dyn_cast<MaterializeTemporaryExpr>(CCE->getArg(0))) {
Expr *Arg = MTE->getSubExpr();
Path.push_back({IndirectLocalPathEntry::TemporaryCopy, Arg,
CCE->getConstructor()});
visitLocalsRetainedByInitializer(Path, Arg, Visit, true,
/*EnableLifetimeWarnings*/false);
Path.pop_back();
}
}
}
if (isa<CallExpr>(Init) || isa<CXXConstructExpr>(Init)) {
if (EnableLifetimeWarnings)
handleGslAnnotatedTypes(Path, Init, Visit);
return visitLifetimeBoundArguments(Path, Init, Visit);
}
switch (Init->getStmtClass()) {
case Stmt::UnaryOperatorClass: {
auto *UO = cast<UnaryOperator>(Init);
// If the initializer is the address of a local, we could have a lifetime
// problem.
if (UO->getOpcode() == UO_AddrOf) {
// If this is &rvalue, then it's ill-formed and we have already diagnosed
// it. Don't produce a redundant warning about the lifetime of the
// temporary.
if (isa<MaterializeTemporaryExpr>(UO->getSubExpr()))
return;
Path.push_back({IndirectLocalPathEntry::AddressOf, UO});
visitLocalsRetainedByReferenceBinding(Path, UO->getSubExpr(),
RK_ReferenceBinding, Visit,
EnableLifetimeWarnings);
}
break;
}
case Stmt::BinaryOperatorClass: {
// Handle pointer arithmetic.
auto *BO = cast<BinaryOperator>(Init);
BinaryOperatorKind BOK = BO->getOpcode();
if (!BO->getType()->isPointerType() || (BOK != BO_Add && BOK != BO_Sub))
break;
if (BO->getLHS()->getType()->isPointerType())
visitLocalsRetainedByInitializer(Path, BO->getLHS(), Visit, true,
EnableLifetimeWarnings);
else if (BO->getRHS()->getType()->isPointerType())
visitLocalsRetainedByInitializer(Path, BO->getRHS(), Visit, true,
EnableLifetimeWarnings);
break;
}
case Stmt::ConditionalOperatorClass:
case Stmt::BinaryConditionalOperatorClass: {
auto *C = cast<AbstractConditionalOperator>(Init);
// In C++, we can have a throw-expression operand, which has 'void' type
// and isn't interesting from a lifetime perspective.
if (!C->getTrueExpr()->getType()->isVoidType())
visitLocalsRetainedByInitializer(Path, C->getTrueExpr(), Visit, true,
EnableLifetimeWarnings);
if (!C->getFalseExpr()->getType()->isVoidType())
visitLocalsRetainedByInitializer(Path, C->getFalseExpr(), Visit, true,
EnableLifetimeWarnings);
break;
}
case Stmt::BlockExprClass:
if (cast<BlockExpr>(Init)->getBlockDecl()->hasCaptures()) {
// This is a local block, whose lifetime is that of the function.
Visit(Path, Local(cast<BlockExpr>(Init)), RK_ReferenceBinding);
}
break;
case Stmt::AddrLabelExprClass:
// We want to warn if the address of a label would escape the function.
Visit(Path, Local(cast<AddrLabelExpr>(Init)), RK_ReferenceBinding);
break;
default:
break;
}
}
/// Whether a path to an object supports lifetime extension.
enum PathLifetimeKind {
/// Lifetime-extend along this path.
Extend,
/// We should lifetime-extend, but we don't because (due to technical
/// limitations) we can't. This happens for default member initializers,
/// which we don't clone for every use, so we don't have a unique
/// MaterializeTemporaryExpr to update.
ShouldExtend,
/// Do not lifetime extend along this path.
NoExtend
};
/// Determine whether this is an indirect path to a temporary that we are
/// supposed to lifetime-extend along.
static PathLifetimeKind
shouldLifetimeExtendThroughPath(const IndirectLocalPath &Path) {
PathLifetimeKind Kind = PathLifetimeKind::Extend;
for (auto Elem : Path) {
if (Elem.Kind == IndirectLocalPathEntry::DefaultInit)
Kind = PathLifetimeKind::ShouldExtend;
else if (Elem.Kind != IndirectLocalPathEntry::LambdaCaptureInit)
return PathLifetimeKind::NoExtend;
}
return Kind;
}
/// Find the range for the first interesting entry in the path at or after I.
static SourceRange nextPathEntryRange(const IndirectLocalPath &Path, unsigned I,
Expr *E) {
for (unsigned N = Path.size(); I != N; ++I) {
switch (Path[I].Kind) {
case IndirectLocalPathEntry::AddressOf:
case IndirectLocalPathEntry::LValToRVal:
case IndirectLocalPathEntry::LifetimeBoundCall:
case IndirectLocalPathEntry::TemporaryCopy:
case IndirectLocalPathEntry::GslReferenceInit:
case IndirectLocalPathEntry::GslPointerInit:
// These exist primarily to mark the path as not permitting or
// supporting lifetime extension.
break;
case IndirectLocalPathEntry::VarInit:
if (cast<VarDecl>(Path[I].D)->isImplicit())
return SourceRange();
LLVM_FALLTHROUGH;
case IndirectLocalPathEntry::DefaultInit:
return Path[I].E->getSourceRange();
case IndirectLocalPathEntry::LambdaCaptureInit:
if (!Path[I].Capture->capturesVariable())
continue;
return Path[I].E->getSourceRange();
}
}
return E->getSourceRange();
}
static bool pathOnlyInitializesGslPointer(IndirectLocalPath &Path) {
for (auto It = Path.rbegin(), End = Path.rend(); It != End; ++It) {
if (It->Kind == IndirectLocalPathEntry::VarInit)
continue;
if (It->Kind == IndirectLocalPathEntry::AddressOf)
continue;
return It->Kind == IndirectLocalPathEntry::GslPointerInit ||
It->Kind == IndirectLocalPathEntry::GslReferenceInit;
}
return false;
}
void Sema::checkInitializerLifetime(const InitializedEntity &Entity,
Expr *Init) {
LifetimeResult LR = getEntityLifetime(&Entity);
LifetimeKind LK = LR.getInt();
const InitializedEntity *ExtendingEntity = LR.getPointer();
// If this entity doesn't have an interesting lifetime, don't bother looking
// for temporaries within its initializer.
if (LK == LK_FullExpression)
return;
auto TemporaryVisitor = [&](IndirectLocalPath &Path, Local L,
ReferenceKind RK) -> bool {
SourceRange DiagRange = nextPathEntryRange(Path, 0, L);
SourceLocation DiagLoc = DiagRange.getBegin();
auto *MTE = dyn_cast<MaterializeTemporaryExpr>(L);
bool IsGslPtrInitWithGslTempOwner = false;
bool IsLocalGslOwner = false;
if (pathOnlyInitializesGslPointer(Path)) {
if (isa<DeclRefExpr>(L)) {
// We do not want to follow the references when returning a pointer originating
// from a local owner to avoid the following false positive:
// int &p = *localUniquePtr;
// someContainer.add(std::move(localUniquePtr));
// return p;
IsLocalGslOwner = isRecordWithAttr<OwnerAttr>(L->getType());
if (pathContainsInit(Path) || !IsLocalGslOwner)
return false;
} else {
IsGslPtrInitWithGslTempOwner = MTE && !MTE->getExtendingDecl() &&
isRecordWithAttr<OwnerAttr>(MTE->getType());
// Skipping a chain of initializing gsl::Pointer annotated objects.
// We are looking only for the final source to find out if it was
// a local or temporary owner or the address of a local variable/param.
if (!IsGslPtrInitWithGslTempOwner)
return true;
}
}
switch (LK) {
case LK_FullExpression:
llvm_unreachable("already handled this");
case LK_Extended: {
if (!MTE) {
// The initialized entity has lifetime beyond the full-expression,
// and the local entity does too, so don't warn.
//
// FIXME: We should consider warning if a static / thread storage
// duration variable retains an automatic storage duration local.
return false;
}
if (IsGslPtrInitWithGslTempOwner && DiagLoc.isValid()) {
Diag(DiagLoc, diag::warn_dangling_lifetime_pointer) << DiagRange;
return false;
}
switch (shouldLifetimeExtendThroughPath(Path)) {
case PathLifetimeKind::Extend:
// Update the storage duration of the materialized temporary.
// FIXME: Rebuild the expression instead of mutating it.
MTE->setExtendingDecl(ExtendingEntity->getDecl(),
ExtendingEntity->allocateManglingNumber());
// Also visit the temporaries lifetime-extended by this initializer.
return true;
case PathLifetimeKind::ShouldExtend:
// We're supposed to lifetime-extend the temporary along this path (per
// the resolution of DR1815), but we don't support that yet.
//
// FIXME: Properly handle this situation. Perhaps the easiest approach
// would be to clone the initializer expression on each use that would
// lifetime extend its temporaries.
Diag(DiagLoc, diag::warn_unsupported_lifetime_extension)
<< RK << DiagRange;
break;
case PathLifetimeKind::NoExtend:
// If the path goes through the initialization of a variable or field,
// it can't possibly reach a temporary created in this full-expression.
// We will have already diagnosed any problems with the initializer.
if (pathContainsInit(Path))
return false;
Diag(DiagLoc, diag::warn_dangling_variable)
<< RK << !Entity.getParent()
<< ExtendingEntity->getDecl()->isImplicit()
<< ExtendingEntity->getDecl() << Init->isGLValue() << DiagRange;
break;
}
break;
}
case LK_MemInitializer: {
if (isa<MaterializeTemporaryExpr>(L)) {
// Under C++ DR1696, if a mem-initializer (or a default member
// initializer used by the absence of one) would lifetime-extend a
// temporary, the program is ill-formed.
if (auto *ExtendingDecl =
ExtendingEntity ? ExtendingEntity->getDecl() : nullptr) {
if (IsGslPtrInitWithGslTempOwner) {
Diag(DiagLoc, diag::warn_dangling_lifetime_pointer_member)
<< ExtendingDecl << DiagRange;
Diag(ExtendingDecl->getLocation(),
diag::note_ref_or_ptr_member_declared_here)
<< true;
return false;
}
bool IsSubobjectMember = ExtendingEntity != &Entity;
Diag(DiagLoc, shouldLifetimeExtendThroughPath(Path) !=
PathLifetimeKind::NoExtend
? diag::err_dangling_member
: diag::warn_dangling_member)
<< ExtendingDecl << IsSubobjectMember << RK << DiagRange;
// Don't bother adding a note pointing to the field if we're inside
// its default member initializer; our primary diagnostic points to
// the same place in that case.
if (Path.empty() ||
Path.back().Kind != IndirectLocalPathEntry::DefaultInit) {
Diag(ExtendingDecl->getLocation(),
diag::note_lifetime_extending_member_declared_here)
<< RK << IsSubobjectMember;
}
} else {
// We have a mem-initializer but no particular field within it; this
// is either a base class or a delegating initializer directly
// initializing the base-class from something that doesn't live long
// enough.
//
// FIXME: Warn on this.
return false;
}
} else {
// Paths via a default initializer can only occur during error recovery
// (there's no other way that a default initializer can refer to a
// local). Don't produce a bogus warning on those cases.
if (pathContainsInit(Path))
return false;
// Suppress false positives for code like the one below:
// Ctor(unique_ptr<T> up) : member(*up), member2(move(up)) {}
if (IsLocalGslOwner && pathOnlyInitializesGslPointer(Path))
return false;
auto *DRE = dyn_cast<DeclRefExpr>(L);
auto *VD = DRE ? dyn_cast<VarDecl>(DRE->getDecl()) : nullptr;
if (!VD) {
// A member was initialized to a local block.
// FIXME: Warn on this.
return false;
}
if (auto *Member =
ExtendingEntity ? ExtendingEntity->getDecl() : nullptr) {
bool IsPointer = !Member->getType()->isReferenceType();
Diag(DiagLoc, IsPointer ? diag::warn_init_ptr_member_to_parameter_addr
: diag::warn_bind_ref_member_to_parameter)
<< Member << VD << isa<ParmVarDecl>(VD) << DiagRange;
Diag(Member->getLocation(),
diag::note_ref_or_ptr_member_declared_here)
<< (unsigned)IsPointer;
}
}
break;
}
case LK_New:
if (isa<MaterializeTemporaryExpr>(L)) {
if (IsGslPtrInitWithGslTempOwner)
Diag(DiagLoc, diag::warn_dangling_lifetime_pointer) << DiagRange;
else
Diag(DiagLoc, RK == RK_ReferenceBinding
? diag::warn_new_dangling_reference
: diag::warn_new_dangling_initializer_list)
<< !Entity.getParent() << DiagRange;
} else {
// We can't determine if the allocation outlives the local declaration.
return false;
}
break;
case LK_Return:
case LK_StmtExprResult:
if (auto *DRE = dyn_cast<DeclRefExpr>(L)) {
// We can't determine if the local variable outlives the statement
// expression.
if (LK == LK_StmtExprResult)
return false;
Diag(DiagLoc, diag::warn_ret_stack_addr_ref)
<< Entity.getType()->isReferenceType() << DRE->getDecl()
<< isa<ParmVarDecl>(DRE->getDecl()) << DiagRange;
} else if (isa<BlockExpr>(L)) {
Diag(DiagLoc, diag::err_ret_local_block) << DiagRange;
} else if (isa<AddrLabelExpr>(L)) {
// Don't warn when returning a label from a statement expression.
// Leaving the scope doesn't end its lifetime.
if (LK == LK_StmtExprResult)
return false;
Diag(DiagLoc, diag::warn_ret_addr_label) << DiagRange;
} else {
Diag(DiagLoc, diag::warn_ret_local_temp_addr_ref)
<< Entity.getType()->isReferenceType() << DiagRange;
}
break;
}
for (unsigned I = 0; I != Path.size(); ++I) {
auto Elem = Path[I];
switch (Elem.Kind) {
case IndirectLocalPathEntry::AddressOf:
case IndirectLocalPathEntry::LValToRVal:
// These exist primarily to mark the path as not permitting or
// supporting lifetime extension.
break;
case IndirectLocalPathEntry::LifetimeBoundCall:
case IndirectLocalPathEntry::TemporaryCopy:
case IndirectLocalPathEntry::GslPointerInit:
case IndirectLocalPathEntry::GslReferenceInit:
// FIXME: Consider adding a note for these.
break;
case IndirectLocalPathEntry::DefaultInit: {
auto *FD = cast<FieldDecl>(Elem.D);
Diag(FD->getLocation(), diag::note_init_with_default_member_initalizer)
<< FD << nextPathEntryRange(Path, I + 1, L);
break;
}
case IndirectLocalPathEntry::VarInit: {
const VarDecl *VD = cast<VarDecl>(Elem.D);
Diag(VD->getLocation(), diag::note_local_var_initializer)
<< VD->getType()->isReferenceType()
<< VD->isImplicit() << VD->getDeclName()
<< nextPathEntryRange(Path, I + 1, L);
break;
}
case IndirectLocalPathEntry::LambdaCaptureInit:
if (!Elem.Capture->capturesVariable())
break;
// FIXME: We can't easily tell apart an init-capture from a nested
// capture of an init-capture.
const VarDecl *VD = Elem.Capture->getCapturedVar();
Diag(Elem.Capture->getLocation(), diag::note_lambda_capture_initializer)
<< VD << VD->isInitCapture() << Elem.Capture->isExplicit()
<< (Elem.Capture->getCaptureKind() == LCK_ByRef) << VD
<< nextPathEntryRange(Path, I + 1, L);
break;
}
}
// We didn't lifetime-extend, so don't go any further; we don't need more
// warnings or errors on inner temporaries within this one's initializer.
return false;
};
bool EnableLifetimeWarnings = !getDiagnostics().isIgnored(
diag::warn_dangling_lifetime_pointer, SourceLocation());
llvm::SmallVector<IndirectLocalPathEntry, 8> Path;
if (Init->isGLValue())
visitLocalsRetainedByReferenceBinding(Path, Init, RK_ReferenceBinding,
TemporaryVisitor,
EnableLifetimeWarnings);
else
visitLocalsRetainedByInitializer(Path, Init, TemporaryVisitor, false,
EnableLifetimeWarnings);
}
static void DiagnoseNarrowingInInitList(Sema &S,
const ImplicitConversionSequence &ICS,
QualType PreNarrowingType,
QualType EntityType,
const Expr *PostInit);
/// Provide warnings when std::move is used on construction.
static void CheckMoveOnConstruction(Sema &S, const Expr *InitExpr,
bool IsReturnStmt) {
if (!InitExpr)
return;
if (S.inTemplateInstantiation())
return;
QualType DestType = InitExpr->getType();
if (!DestType->isRecordType())
return;
unsigned DiagID = 0;
if (IsReturnStmt) {
const CXXConstructExpr *CCE =
dyn_cast<CXXConstructExpr>(InitExpr->IgnoreParens());
if (!CCE || CCE->getNumArgs() != 1)
return;
if (!CCE->getConstructor()->isCopyOrMoveConstructor())
return;
InitExpr = CCE->getArg(0)->IgnoreImpCasts();
}
// Find the std::move call and get the argument.
const CallExpr *CE = dyn_cast<CallExpr>(InitExpr->IgnoreParens());
if (!CE || !CE->isCallToStdMove())
return;
const Expr *Arg = CE->getArg(0)->IgnoreImplicit();
if (IsReturnStmt) {
const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Arg->IgnoreParenImpCasts());
if (!DRE || DRE->refersToEnclosingVariableOrCapture())
return;
const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl());
if (!VD || !VD->hasLocalStorage())
return;
// __block variables are not moved implicitly.
if (VD->hasAttr<BlocksAttr>())
return;
QualType SourceType = VD->getType();
if (!SourceType->isRecordType())
return;
if (!S.Context.hasSameUnqualifiedType(DestType, SourceType)) {
return;
}
// If we're returning a function parameter, copy elision
// is not possible.
if (isa<ParmVarDecl>(VD))
DiagID = diag::warn_redundant_move_on_return;
else
DiagID = diag::warn_pessimizing_move_on_return;
} else {
DiagID = diag::warn_pessimizing_move_on_initialization;
const Expr *ArgStripped = Arg->IgnoreImplicit()->IgnoreParens();
if (!ArgStripped->isRValue() || !ArgStripped->getType()->isRecordType())
return;
}
S.Diag(CE->getBeginLoc(), DiagID);
// Get all the locations for a fix-it. Don't emit the fix-it if any location
// is within a macro.
SourceLocation CallBegin = CE->getCallee()->getBeginLoc();
if (CallBegin.isMacroID())
return;
SourceLocation RParen = CE->getRParenLoc();
if (RParen.isMacroID())
return;
SourceLocation LParen;
SourceLocation ArgLoc = Arg->getBeginLoc();
// Special testing for the argument location. Since the fix-it needs the
// location right before the argument, the argument location can be in a
// macro only if it is at the beginning of the macro.
while (ArgLoc.isMacroID() &&
S.getSourceManager().isAtStartOfImmediateMacroExpansion(ArgLoc)) {
ArgLoc = S.getSourceManager().getImmediateExpansionRange(ArgLoc).getBegin();
}
if (LParen.isMacroID())
return;
LParen = ArgLoc.getLocWithOffset(-1);
S.Diag(CE->getBeginLoc(), diag::note_remove_move)
<< FixItHint::CreateRemoval(SourceRange(CallBegin, LParen))
<< FixItHint::CreateRemoval(SourceRange(RParen, RParen));
}
static void CheckForNullPointerDereference(Sema &S, const Expr *E) {
// Check to see if we are dereferencing a null pointer. If so, this is
// undefined behavior, so warn about it. This only handles the pattern
// "*null", which is a very syntactic check.
if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(E->IgnoreParenCasts()))
if (UO->getOpcode() == UO_Deref &&
UO->getSubExpr()->IgnoreParenCasts()->
isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull)) {
S.DiagRuntimeBehavior(UO->getOperatorLoc(), UO,
S.PDiag(diag::warn_binding_null_to_reference)
<< UO->getSubExpr()->getSourceRange());
}
}
MaterializeTemporaryExpr *
Sema::CreateMaterializeTemporaryExpr(QualType T, Expr *Temporary,
bool BoundToLvalueReference) {
auto MTE = new (Context)
MaterializeTemporaryExpr(T, Temporary, BoundToLvalueReference);
// Order an ExprWithCleanups for lifetime marks.
//
// TODO: It'll be good to have a single place to check the access of the
// destructor and generate ExprWithCleanups for various uses. Currently these
// are done in both CreateMaterializeTemporaryExpr and MaybeBindToTemporary,
// but there may be a chance to merge them.
Cleanup.setExprNeedsCleanups(false);
return MTE;
}
ExprResult Sema::TemporaryMaterializationConversion(Expr *E) {
// In C++98, we don't want to implicitly create an xvalue.
// FIXME: This means that AST consumers need to deal with "prvalues" that
// denote materialized temporaries. Maybe we should add another ValueKind
// for "xvalue pretending to be a prvalue" for C++98 support.
if (!E->isRValue() || !getLangOpts().CPlusPlus11)
return E;
// C++1z [conv.rval]/1: T shall be a complete type.
// FIXME: Does this ever matter (can we form a prvalue of incomplete type)?
// If so, we should check for a non-abstract class type here too.
QualType T = E->getType();
if (RequireCompleteType(E->getExprLoc(), T, diag::err_incomplete_type))
return ExprError();
return CreateMaterializeTemporaryExpr(E->getType(), E, false);
}
ExprResult Sema::PerformQualificationConversion(Expr *E, QualType Ty,
ExprValueKind VK,
CheckedConversionKind CCK) {
CastKind CK = CK_NoOp;
if (VK == VK_RValue) {
auto PointeeTy = Ty->getPointeeType();
auto ExprPointeeTy = E->getType()->getPointeeType();
if (!PointeeTy.isNull() &&
PointeeTy.getAddressSpace() != ExprPointeeTy.getAddressSpace())
CK = CK_AddressSpaceConversion;
} else if (Ty.getAddressSpace() != E->getType().getAddressSpace()) {
CK = CK_AddressSpaceConversion;
}
return ImpCastExprToType(E, Ty, CK, VK, /*BasePath=*/nullptr, CCK);
}
ExprResult InitializationSequence::Perform(Sema &S,
const InitializedEntity &Entity,
const InitializationKind &Kind,
MultiExprArg Args,
QualType *ResultType) {
if (Failed()) {
Diagnose(S, Entity, Kind, Args);
return ExprError();
}
if (!ZeroInitializationFixit.empty()) {
unsigned DiagID = diag::err_default_init_const;
if (Decl *D = Entity.getDecl())
if (S.getLangOpts().MSVCCompat && D->hasAttr<SelectAnyAttr>())
DiagID = diag::ext_default_init_const;
// The initialization would have succeeded with this fixit. Since the fixit
// is on the error, we need to build a valid AST in this case, so this isn't
// handled in the Failed() branch above.
QualType DestType = Entity.getType();
S.Diag(Kind.getLocation(), DiagID)
<< DestType << (bool)DestType->getAs<RecordType>()
<< FixItHint::CreateInsertion(ZeroInitializationFixitLoc,
ZeroInitializationFixit);
}
if (getKind() == DependentSequence) {
// If the declaration is a non-dependent, incomplete array type
// that has an initializer, then its type will be completed once
// the initializer is instantiated.
if (ResultType && !Entity.getType()->isDependentType() &&
Args.size() == 1) {
QualType DeclType = Entity.getType();
if (const IncompleteArrayType *ArrayT
= S.Context.getAsIncompleteArrayType(DeclType)) {
// FIXME: We don't currently have the ability to accurately
// compute the length of an initializer list without
// performing full type-checking of the initializer list
// (since we have to determine where braces are implicitly
// introduced and such). So, we fall back to making the array
// type a dependently-sized array type with no specified
// bound.
if (isa<InitListExpr>((Expr *)Args[0])) {
SourceRange Brackets;
// Scavange the location of the brackets from the entity, if we can.
if (auto *DD = dyn_cast_or_null<DeclaratorDecl>(Entity.getDecl())) {
if (TypeSourceInfo *TInfo = DD->getTypeSourceInfo()) {
TypeLoc TL = TInfo->getTypeLoc();
if (IncompleteArrayTypeLoc ArrayLoc =
TL.getAs<IncompleteArrayTypeLoc>())
Brackets = ArrayLoc.getBracketsRange();
}
}
*ResultType
= S.Context.getDependentSizedArrayType(ArrayT->getElementType(),
/*NumElts=*/nullptr,
ArrayT->getSizeModifier(),
ArrayT->getIndexTypeCVRQualifiers(),
Brackets);
}
}
}
if (Kind.getKind() == InitializationKind::IK_Direct &&
!Kind.isExplicitCast()) {
// Rebuild the ParenListExpr.
SourceRange ParenRange = Kind.getParenOrBraceRange();
return S.ActOnParenListExpr(ParenRange.getBegin(), ParenRange.getEnd(),
Args);
}
assert(Kind.getKind() == InitializationKind::IK_Copy ||
Kind.isExplicitCast() ||
Kind.getKind() == InitializationKind::IK_DirectList);
return ExprResult(Args[0]);
}
// No steps means no initialization.
if (Steps.empty())
return ExprResult((Expr *)nullptr);
if (S.getLangOpts().CPlusPlus11 && Entity.getType()->isReferenceType() &&
Args.size() == 1 && isa<InitListExpr>(Args[0]) &&
!Entity.isParamOrTemplateParamKind()) {
// Produce a C++98 compatibility warning if we are initializing a reference
// from an initializer list. For parameters, we produce a better warning
// elsewhere.
Expr *Init = Args[0];
S.Diag(Init->getBeginLoc(), diag::warn_cxx98_compat_reference_list_init)
<< Init->getSourceRange();
}
// OpenCL v2.0 s6.13.11.1. atomic variables can be initialized in global scope
QualType ETy = Entity.getType();
bool HasGlobalAS = ETy.hasAddressSpace() &&
ETy.getAddressSpace() == LangAS::opencl_global;
if (S.getLangOpts().OpenCLVersion >= 200 &&
ETy->isAtomicType() && !HasGlobalAS &&
Entity.getKind() == InitializedEntity::EK_Variable && Args.size() > 0) {
S.Diag(Args[0]->getBeginLoc(), diag::err_opencl_atomic_init)
<< 1
<< SourceRange(Entity.getDecl()->getBeginLoc(), Args[0]->getEndLoc());
return ExprError();
}
QualType DestType = Entity.getType().getNonReferenceType();
// FIXME: Ugly hack around the fact that Entity.getType() is not
// the same as Entity.getDecl()->getType() in cases involving type merging,
// and we want latter when it makes sense.
if (ResultType)
*ResultType = Entity.getDecl() ? Entity.getDecl()->getType() :
Entity.getType();
ExprResult CurInit((Expr *)nullptr);
SmallVector<Expr*, 4> ArrayLoopCommonExprs;
// For initialization steps that start with a single initializer,
// grab the only argument out the Args and place it into the "current"
// initializer.
switch (Steps.front().Kind) {
case SK_ResolveAddressOfOverloadedFunction:
case SK_CastDerivedToBaseRValue:
case SK_CastDerivedToBaseXValue:
case SK_CastDerivedToBaseLValue:
case SK_BindReference:
case SK_BindReferenceToTemporary:
case SK_FinalCopy:
case SK_ExtraneousCopyToTemporary:
case SK_UserConversion:
case SK_QualificationConversionLValue:
case SK_QualificationConversionXValue:
case SK_QualificationConversionRValue:
case SK_FunctionReferenceConversion:
case SK_AtomicConversion:
case SK_ConversionSequence:
case SK_ConversionSequenceNoNarrowing:
case SK_ListInitialization:
case SK_UnwrapInitList:
case SK_RewrapInitList:
case SK_CAssignment:
case SK_StringInit:
case SK_ObjCObjectConversion:
case SK_ArrayLoopIndex:
case SK_ArrayLoopInit:
case SK_ArrayInit:
case SK_GNUArrayInit:
case SK_ParenthesizedArrayInit:
case SK_PassByIndirectCopyRestore:
case SK_PassByIndirectRestore:
case SK_ProduceObjCObject:
case SK_StdInitializerList:
case SK_OCLSamplerInit:
case SK_OCLZeroOpaqueType: {
assert(Args.size() == 1);
CurInit = Args[0];
if (!CurInit.get()) return ExprError();
break;
}
case SK_ConstructorInitialization:
case SK_ConstructorInitializationFromList:
case SK_StdInitializerListConstructorCall:
case SK_ZeroInitialization:
break;
}
// Promote from an unevaluated context to an unevaluated list context in
// C++11 list-initialization; we need to instantiate entities usable in
// constant expressions here in order to perform narrowing checks =(
EnterExpressionEvaluationContext Evaluated(
S, EnterExpressionEvaluationContext::InitList,
CurInit.get() && isa<InitListExpr>(CurInit.get()));
// C++ [class.abstract]p2:
// no objects of an abstract class can be created except as subobjects
// of a class derived from it
auto checkAbstractType = [&](QualType T) -> bool {
if (Entity.getKind() == InitializedEntity::EK_Base ||
Entity.getKind() == InitializedEntity::EK_Delegating)
return false;
return S.RequireNonAbstractType(Kind.getLocation(), T,
diag::err_allocation_of_abstract_type);
};
// Walk through the computed steps for the initialization sequence,
// performing the specified conversions along the way.
bool ConstructorInitRequiresZeroInit = false;
for (step_iterator Step = step_begin(), StepEnd = step_end();
Step != StepEnd; ++Step) {
if (CurInit.isInvalid())
return ExprError();
QualType SourceType = CurInit.get() ? CurInit.get()->getType() : QualType();
switch (Step->Kind) {
case SK_ResolveAddressOfOverloadedFunction:
// Overload resolution determined which function invoke; update the
// initializer to reflect that choice.
S.CheckAddressOfMemberAccess(CurInit.get(), Step->Function.FoundDecl);
if (S.DiagnoseUseOfDecl(Step->Function.FoundDecl, Kind.getLocation()))
return ExprError();
CurInit = S.FixOverloadedFunctionReference(CurInit,
Step->Function.FoundDecl,
Step->Function.Function);
break;
case SK_CastDerivedToBaseRValue:
case SK_CastDerivedToBaseXValue:
case SK_CastDerivedToBaseLValue: {
// We have a derived-to-base cast that produces either an rvalue or an
// lvalue. Perform that cast.
CXXCastPath BasePath;
// Casts to inaccessible base classes are allowed with C-style casts.
bool IgnoreBaseAccess = Kind.isCStyleOrFunctionalCast();
if (S.CheckDerivedToBaseConversion(
SourceType, Step->Type, CurInit.get()->getBeginLoc(),
CurInit.get()->getSourceRange(), &BasePath, IgnoreBaseAccess))
return ExprError();
ExprValueKind VK =
Step->Kind == SK_CastDerivedToBaseLValue ?
VK_LValue :
(Step->Kind == SK_CastDerivedToBaseXValue ?
VK_XValue :
VK_RValue);
CurInit = ImplicitCastExpr::Create(S.Context, Step->Type,
CK_DerivedToBase, CurInit.get(),
&BasePath, VK, FPOptionsOverride());
break;
}
case SK_BindReference:
// Reference binding does not have any corresponding ASTs.
// Check exception specifications
if (S.CheckExceptionSpecCompatibility(CurInit.get(), DestType))
return ExprError();
// We don't check for e.g. function pointers here, since address
// availability checks should only occur when the function first decays
// into a pointer or reference.
if (CurInit.get()->getType()->isFunctionProtoType()) {
if (auto *DRE = dyn_cast<DeclRefExpr>(CurInit.get()->IgnoreParens())) {
if (auto *FD = dyn_cast<FunctionDecl>(DRE->getDecl())) {
if (!S.checkAddressOfFunctionIsAvailable(FD, /*Complain=*/true,
DRE->getBeginLoc()))
return ExprError();
}
}
}
CheckForNullPointerDereference(S, CurInit.get());
break;
case SK_BindReferenceToTemporary: {
// Make sure the "temporary" is actually an rvalue.
assert(CurInit.get()->isRValue() && "not a temporary");
// Check exception specifications
if (S.CheckExceptionSpecCompatibility(CurInit.get(), DestType))
return ExprError();
QualType MTETy = Step->Type;
// When this is an incomplete array type (such as when this is
// initializing an array of unknown bounds from an init list), use THAT
// type instead so that we propogate the array bounds.
if (MTETy->isIncompleteArrayType() &&
!CurInit.get()->getType()->isIncompleteArrayType() &&
S.Context.hasSameType(
MTETy->getPointeeOrArrayElementType(),
CurInit.get()->getType()->getPointeeOrArrayElementType()))
MTETy = CurInit.get()->getType();
// Materialize the temporary into memory.
MaterializeTemporaryExpr *MTE = S.CreateMaterializeTemporaryExpr(
MTETy, CurInit.get(), Entity.getType()->isLValueReferenceType());
CurInit = MTE;
// If we're extending this temporary to automatic storage duration -- we
// need to register its cleanup during the full-expression's cleanups.
if (MTE->getStorageDuration() == SD_Automatic &&
MTE->getType().isDestructedType())
S.Cleanup.setExprNeedsCleanups(true);
break;
}
case SK_FinalCopy:
if (checkAbstractType(Step->Type))
return ExprError();
// If the overall initialization is initializing a temporary, we already
// bound our argument if it was necessary to do so. If not (if we're
// ultimately initializing a non-temporary), our argument needs to be
// bound since it's initializing a function parameter.
// FIXME: This is a mess. Rationalize temporary destruction.
if (!shouldBindAsTemporary(Entity))
CurInit = S.MaybeBindToTemporary(CurInit.get());
CurInit = CopyObject(S, Step->Type, Entity, CurInit,
/*IsExtraneousCopy=*/false);
break;
case SK_ExtraneousCopyToTemporary:
CurInit = CopyObject(S, Step->Type, Entity, CurInit,
/*IsExtraneousCopy=*/true);
break;
case SK_UserConversion: {
// We have a user-defined conversion that invokes either a constructor
// or a conversion function.
CastKind CastKind;
FunctionDecl *Fn = Step->Function.Function;
DeclAccessPair FoundFn = Step->Function.FoundDecl;
bool HadMultipleCandidates = Step->Function.HadMultipleCandidates;
bool CreatedObject = false;
if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(Fn)) {
// Build a call to the selected constructor.
SmallVector<Expr*, 8> ConstructorArgs;
SourceLocation Loc = CurInit.get()->getBeginLoc();
// Determine the arguments required to actually perform the constructor
// call.
Expr *Arg = CurInit.get();
if (S.CompleteConstructorCall(Constructor,
MultiExprArg(&Arg, 1),
Loc, ConstructorArgs))
return ExprError();
// Build an expression that constructs a temporary.
CurInit = S.BuildCXXConstructExpr(Loc, Step->Type,
FoundFn, Constructor,
ConstructorArgs,
HadMultipleCandidates,
/*ListInit*/ false,
/*StdInitListInit*/ false,
/*ZeroInit*/ false,
CXXConstructExpr::CK_Complete,
SourceRange());
if (CurInit.isInvalid())
return ExprError();
S.CheckConstructorAccess(Kind.getLocation(), Constructor, FoundFn,
Entity);
if (S.DiagnoseUseOfDecl(FoundFn, Kind.getLocation()))
return ExprError();
CastKind = CK_ConstructorConversion;
CreatedObject = true;
} else {
// Build a call to the conversion function.
CXXConversionDecl *Conversion = cast<CXXConversionDecl>(Fn);
S.CheckMemberOperatorAccess(Kind.getLocation(), CurInit.get(), nullptr,
FoundFn);
if (S.DiagnoseUseOfDecl(FoundFn, Kind.getLocation()))
return ExprError();
CurInit = S.BuildCXXMemberCallExpr(CurInit.get(), FoundFn, Conversion,
HadMultipleCandidates);
if (CurInit.isInvalid())
return ExprError();
CastKind = CK_UserDefinedConversion;
CreatedObject = Conversion->getReturnType()->isRecordType();
}
if (CreatedObject && checkAbstractType(CurInit.get()->getType()))
return ExprError();
CurInit = ImplicitCastExpr::Create(
S.Context, CurInit.get()->getType(), CastKind, CurInit.get(), nullptr,
CurInit.get()->getValueKind(), S.CurFPFeatureOverrides());
if (shouldBindAsTemporary(Entity))
// The overall entity is temporary, so this expression should be
// destroyed at the end of its full-expression.
CurInit = S.MaybeBindToTemporary(CurInit.getAs<Expr>());
else if (CreatedObject && shouldDestroyEntity(Entity)) {
// The object outlasts the full-expression, but we need to prepare for
// a destructor being run on it.
// FIXME: It makes no sense to do this here. This should happen
// regardless of how we initialized the entity.
QualType T = CurInit.get()->getType();
if (const RecordType *Record = T->getAs<RecordType>()) {
CXXDestructorDecl *Destructor
= S.LookupDestructor(cast<CXXRecordDecl>(Record->getDecl()));
S.CheckDestructorAccess(CurInit.get()->getBeginLoc(), Destructor,
S.PDiag(diag::err_access_dtor_temp) << T);
S.MarkFunctionReferenced(CurInit.get()->getBeginLoc(), Destructor);
if (S.DiagnoseUseOfDecl(Destructor, CurInit.get()->getBeginLoc()))
return ExprError();
}
}
break;
}
case SK_QualificationConversionLValue:
case SK_QualificationConversionXValue:
case SK_QualificationConversionRValue: {
// Perform a qualification conversion; these can never go wrong.
ExprValueKind VK =
Step->Kind == SK_QualificationConversionLValue
? VK_LValue
: (Step->Kind == SK_QualificationConversionXValue ? VK_XValue
: VK_RValue);
CurInit = S.PerformQualificationConversion(CurInit.get(), Step->Type, VK);
break;
}
case SK_FunctionReferenceConversion:
assert(CurInit.get()->isLValue() &&
"function reference should be lvalue");
CurInit =
S.ImpCastExprToType(CurInit.get(), Step->Type, CK_NoOp, VK_LValue);
break;
case SK_AtomicConversion: {
assert(CurInit.get()->isRValue() && "cannot convert glvalue to atomic");
CurInit = S.ImpCastExprToType(CurInit.get(), Step->Type,
CK_NonAtomicToAtomic, VK_RValue);
break;
}
case SK_ConversionSequence:
case SK_ConversionSequenceNoNarrowing: {
if (const auto *FromPtrType =
CurInit.get()->getType()->getAs<PointerType>()) {
if (const auto *ToPtrType = Step->Type->getAs<PointerType>()) {
if (FromPtrType->getPointeeType()->hasAttr(attr::NoDeref) &&
!ToPtrType->getPointeeType()->hasAttr(attr::NoDeref)) {
// Do not check static casts here because they are checked earlier
// in Sema::ActOnCXXNamedCast()
if (!Kind.isStaticCast()) {
S.Diag(CurInit.get()->getExprLoc(),
diag::warn_noderef_to_dereferenceable_pointer)
<< CurInit.get()->getSourceRange();
}
}
}
}
Sema::CheckedConversionKind CCK
= Kind.isCStyleCast()? Sema::CCK_CStyleCast
: Kind.isFunctionalCast()? Sema::CCK_FunctionalCast
: Kind.isExplicitCast()? Sema::CCK_OtherCast
: Sema::CCK_ImplicitConversion;
ExprResult CurInitExprRes =
S.PerformImplicitConversion(CurInit.get(), Step->Type, *Step->ICS,
getAssignmentAction(Entity), CCK);
if (CurInitExprRes.isInvalid())
return ExprError();
S.DiscardMisalignedMemberAddress(Step->Type.getTypePtr(), CurInit.get());
CurInit = CurInitExprRes;
if (Step->Kind == SK_ConversionSequenceNoNarrowing &&
S.getLangOpts().CPlusPlus)
DiagnoseNarrowingInInitList(S, *Step->ICS, SourceType, Entity.getType(),
CurInit.get());
break;
}
case SK_ListInitialization: {
if (checkAbstractType(Step->Type))
return ExprError();
InitListExpr *InitList = cast<InitListExpr>(CurInit.get());
// If we're not initializing the top-level entity, we need to create an
// InitializeTemporary entity for our target type.
QualType Ty = Step->Type;
bool IsTemporary = !S.Context.hasSameType(Entity.getType(), Ty);
InitializedEntity TempEntity = InitializedEntity::InitializeTemporary(Ty);
InitializedEntity InitEntity = IsTemporary ? TempEntity : Entity;
InitListChecker PerformInitList(S, InitEntity,
InitList, Ty, /*VerifyOnly=*/false,
/*TreatUnavailableAsInvalid=*/false);
if (PerformInitList.HadError())
return ExprError();
// Hack: We must update *ResultType if available in order to set the
// bounds of arrays, e.g. in 'int ar[] = {1, 2, 3};'.
// Worst case: 'const int (&arref)[] = {1, 2, 3};'.
if (ResultType &&
ResultType->getNonReferenceType()->isIncompleteArrayType()) {
if ((*ResultType)->isRValueReferenceType())
Ty = S.Context.getRValueReferenceType(Ty);
else if ((*ResultType)->isLValueReferenceType())
Ty = S.Context.getLValueReferenceType(Ty,
(*ResultType)->castAs<LValueReferenceType>()->isSpelledAsLValue());
*ResultType = Ty;
}
InitListExpr *StructuredInitList =
PerformInitList.getFullyStructuredList();
CurInit.get();
CurInit = shouldBindAsTemporary(InitEntity)
? S.MaybeBindToTemporary(StructuredInitList)
: StructuredInitList;
break;
}
case SK_ConstructorInitializationFromList: {
if (checkAbstractType(Step->Type))
return ExprError();
// When an initializer list is passed for a parameter of type "reference
// to object", we don't get an EK_Temporary entity, but instead an
// EK_Parameter entity with reference type.
// FIXME: This is a hack. What we really should do is create a user
// conversion step for this case, but this makes it considerably more
// complicated. For now, this will do.
InitializedEntity TempEntity = InitializedEntity::InitializeTemporary(
Entity.getType().getNonReferenceType());
bool UseTemporary = Entity.getType()->isReferenceType();
assert(Args.size() == 1 && "expected a single argument for list init");
InitListExpr *InitList = cast<InitListExpr>(Args[0]);
S.Diag(InitList->getExprLoc(), diag::warn_cxx98_compat_ctor_list_init)
<< InitList->getSourceRange();
MultiExprArg Arg(InitList->getInits(), InitList->getNumInits());
CurInit = PerformConstructorInitialization(S, UseTemporary ? TempEntity :
Entity,
Kind, Arg, *Step,
ConstructorInitRequiresZeroInit,
/*IsListInitialization*/true,
/*IsStdInitListInit*/false,
InitList->getLBraceLoc(),
InitList->getRBraceLoc());
break;
}
case SK_UnwrapInitList:
CurInit = cast<InitListExpr>(CurInit.get())->getInit(0);
break;
case SK_RewrapInitList: {
Expr *E = CurInit.get();
InitListExpr *Syntactic = Step->WrappingSyntacticList;
InitListExpr *ILE = new (S.Context) InitListExpr(S.Context,
Syntactic->getLBraceLoc(), E, Syntactic->getRBraceLoc());
ILE->setSyntacticForm(Syntactic);
ILE->setType(E->getType());
ILE->setValueKind(E->getValueKind());
CurInit = ILE;
break;
}
case SK_ConstructorInitialization:
case SK_StdInitializerListConstructorCall: {
if (checkAbstractType(Step->Type))
return ExprError();
// When an initializer list is passed for a parameter of type "reference
// to object", we don't get an EK_Temporary entity, but instead an
// EK_Parameter entity with reference type.
// FIXME: This is a hack. What we really should do is create a user
// conversion step for this case, but this makes it considerably more
// complicated. For now, this will do.
InitializedEntity TempEntity = InitializedEntity::InitializeTemporary(
Entity.getType().getNonReferenceType());
bool UseTemporary = Entity.getType()->isReferenceType();
bool IsStdInitListInit =
Step->Kind == SK_StdInitializerListConstructorCall;
Expr *Source = CurInit.get();
SourceRange Range = Kind.hasParenOrBraceRange()
? Kind.getParenOrBraceRange()
: SourceRange();
CurInit = PerformConstructorInitialization(
S, UseTemporary ? TempEntity : Entity, Kind,
Source ? MultiExprArg(Source) : Args, *Step,
ConstructorInitRequiresZeroInit,
/*IsListInitialization*/ IsStdInitListInit,
/*IsStdInitListInitialization*/ IsStdInitListInit,
/*LBraceLoc*/ Range.getBegin(),
/*RBraceLoc*/ Range.getEnd());
break;
}
case SK_ZeroInitialization: {
step_iterator NextStep = Step;
++NextStep;
if (NextStep != StepEnd &&
(NextStep->Kind == SK_ConstructorInitialization ||
NextStep->Kind == SK_ConstructorInitializationFromList)) {
// The need for zero-initialization is recorded directly into
// the call to the object's constructor within the next step.
ConstructorInitRequiresZeroInit = true;
} else if (Kind.getKind() == InitializationKind::IK_Value &&
S.getLangOpts().CPlusPlus &&
!Kind.isImplicitValueInit()) {
TypeSourceInfo *TSInfo = Entity.getTypeSourceInfo();
if (!TSInfo)
TSInfo = S.Context.getTrivialTypeSourceInfo(Step->Type,
Kind.getRange().getBegin());
CurInit = new (S.Context) CXXScalarValueInitExpr(
Entity.getType().getNonLValueExprType(S.Context), TSInfo,
Kind.getRange().getEnd());
} else {
CurInit = new (S.Context) ImplicitValueInitExpr(Step->Type);
}
break;
}
case SK_CAssignment: {
QualType SourceType = CurInit.get()->getType();
// Save off the initial CurInit in case we need to emit a diagnostic
ExprResult InitialCurInit = CurInit;
ExprResult Result = CurInit;
Sema::AssignConvertType ConvTy =
S.CheckSingleAssignmentConstraints(Step->Type, Result, true,
Entity.getKind() == InitializedEntity::EK_Parameter_CF_Audited);
if (Result.isInvalid())
return ExprError();
CurInit = Result;
// If this is a call, allow conversion to a transparent union.
ExprResult CurInitExprRes = CurInit;
if (ConvTy != Sema::Compatible &&
Entity.isParameterKind() &&
S.CheckTransparentUnionArgumentConstraints(Step->Type, CurInitExprRes)
== Sema::Compatible)
ConvTy = Sema::Compatible;
if (CurInitExprRes.isInvalid())
return ExprError();
CurInit = CurInitExprRes;
bool Complained;
if (S.DiagnoseAssignmentResult(ConvTy, Kind.getLocation(),
Step->Type, SourceType,
InitialCurInit.get(),
getAssignmentAction(Entity, true),
&Complained)) {
PrintInitLocationNote(S, Entity);
return ExprError();
} else if (Complained)
PrintInitLocationNote(S, Entity);
break;
}
case SK_StringInit: {
QualType Ty = Step->Type;
bool UpdateType = ResultType && Entity.getType()->isIncompleteArrayType();
CheckStringInit(CurInit.get(), UpdateType ? *ResultType : Ty,
S.Context.getAsArrayType(Ty), S);
break;
}
case SK_ObjCObjectConversion:
CurInit = S.ImpCastExprToType(CurInit.get(), Step->Type,
CK_ObjCObjectLValueCast,
CurInit.get()->getValueKind());
break;
case SK_ArrayLoopIndex: {
Expr *Cur = CurInit.get();
Expr *BaseExpr = new (S.Context)
OpaqueValueExpr(Cur->getExprLoc(), Cur->getType(),
Cur->getValueKind(), Cur->getObjectKind(), Cur);
Expr *IndexExpr =
new (S.Context) ArrayInitIndexExpr(S.Context.getSizeType());
CurInit = S.CreateBuiltinArraySubscriptExpr(
BaseExpr, Kind.getLocation(), IndexExpr, Kind.getLocation());
ArrayLoopCommonExprs.push_back(BaseExpr);
break;
}
case SK_ArrayLoopInit: {
assert(!ArrayLoopCommonExprs.empty() &&
"mismatched SK_ArrayLoopIndex and SK_ArrayLoopInit");
Expr *Common = ArrayLoopCommonExprs.pop_back_val();
CurInit = new (S.Context) ArrayInitLoopExpr(Step->Type, Common,
CurInit.get());
break;
}
case SK_GNUArrayInit:
// Okay: we checked everything before creating this step. Note that
// this is a GNU extension.
S.Diag(Kind.getLocation(), diag::ext_array_init_copy)
<< Step->Type << CurInit.get()->getType()
<< CurInit.get()->getSourceRange();
updateGNUCompoundLiteralRValue(CurInit.get());
LLVM_FALLTHROUGH;
case SK_ArrayInit:
// If the destination type is an incomplete array type, update the
// type accordingly.
if (ResultType) {
if (const IncompleteArrayType *IncompleteDest
= S.Context.getAsIncompleteArrayType(Step->Type)) {
if (const ConstantArrayType *ConstantSource
= S.Context.getAsConstantArrayType(CurInit.get()->getType())) {
*ResultType = S.Context.getConstantArrayType(
IncompleteDest->getElementType(),
ConstantSource->getSize(),
ConstantSource->getSizeExpr(),
ArrayType::Normal, 0);
}
}
}
break;
case SK_ParenthesizedArrayInit:
// Okay: we checked everything before creating this step. Note that
// this is a GNU extension.
S.Diag(Kind.getLocation(), diag::ext_array_init_parens)
<< CurInit.get()->getSourceRange();
break;
case SK_PassByIndirectCopyRestore:
case SK_PassByIndirectRestore:
checkIndirectCopyRestoreSource(S, CurInit.get());
CurInit = new (S.Context) ObjCIndirectCopyRestoreExpr(
CurInit.get(), Step->Type,
Step->Kind == SK_PassByIndirectCopyRestore);
break;
case SK_ProduceObjCObject:
CurInit = ImplicitCastExpr::Create(
S.Context, Step->Type, CK_ARCProduceObject, CurInit.get(), nullptr,
VK_RValue, FPOptionsOverride());
break;
case SK_StdInitializerList: {
S.Diag(CurInit.get()->getExprLoc(),
diag::warn_cxx98_compat_initializer_list_init)
<< CurInit.get()->getSourceRange();
// Materialize the temporary into memory.
MaterializeTemporaryExpr *MTE = S.CreateMaterializeTemporaryExpr(
CurInit.get()->getType(), CurInit.get(),
/*BoundToLvalueReference=*/false);
// Wrap it in a construction of a std::initializer_list<T>.
CurInit = new (S.Context) CXXStdInitializerListExpr(Step->Type, MTE);
// Bind the result, in case the library has given initializer_list a
// non-trivial destructor.
if (shouldBindAsTemporary(Entity))
CurInit = S.MaybeBindToTemporary(CurInit.get());
break;
}
case SK_OCLSamplerInit: {
// Sampler initialization have 5 cases:
// 1. function argument passing
// 1a. argument is a file-scope variable
// 1b. argument is a function-scope variable
// 1c. argument is one of caller function's parameters
// 2. variable initialization
// 2a. initializing a file-scope variable
// 2b. initializing a function-scope variable
//
// For file-scope variables, since they cannot be initialized by function
// call of __translate_sampler_initializer in LLVM IR, their references
// need to be replaced by a cast from their literal initializers to
// sampler type. Since sampler variables can only be used in function
// calls as arguments, we only need to replace them when handling the
// argument passing.
assert(Step->Type->isSamplerT() &&
"Sampler initialization on non-sampler type.");
Expr *Init = CurInit.get()->IgnoreParens();
QualType SourceType = Init->getType();
// Case 1
if (Entity.isParameterKind()) {
if (!SourceType->isSamplerT() && !SourceType->isIntegerType()) {
S.Diag(Kind.getLocation(), diag::err_sampler_argument_required)
<< SourceType;
break;
} else if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Init)) {
auto Var = cast<VarDecl>(DRE->getDecl());
// Case 1b and 1c
// No cast from integer to sampler is needed.
if (!Var->hasGlobalStorage()) {
CurInit = ImplicitCastExpr::Create(
S.Context, Step->Type, CK_LValueToRValue, Init,
/*BasePath=*/nullptr, VK_RValue, FPOptionsOverride());
break;
}
// Case 1a
// For function call with a file-scope sampler variable as argument,
// get the integer literal.
// Do not diagnose if the file-scope variable does not have initializer
// since this has already been diagnosed when parsing the variable
// declaration.
if (!Var->getInit() || !isa<ImplicitCastExpr>(Var->getInit()))
break;
Init = cast<ImplicitCastExpr>(const_cast<Expr*>(
Var->getInit()))->getSubExpr();
SourceType = Init->getType();
}
} else {
// Case 2
// Check initializer is 32 bit integer constant.
// If the initializer is taken from global variable, do not diagnose since
// this has already been done when parsing the variable declaration.
if (!Init->isConstantInitializer(S.Context, false))
break;
if (!SourceType->isIntegerType() ||
32 != S.Context.getIntWidth(SourceType)) {
S.Diag(Kind.getLocation(), diag::err_sampler_initializer_not_integer)
<< SourceType;
break;
}
Expr::EvalResult EVResult;
Init->EvaluateAsInt(EVResult, S.Context);
llvm::APSInt Result = EVResult.Val.getInt();
const uint64_t SamplerValue = Result.getLimitedValue();
// 32-bit value of sampler's initializer is interpreted as
// bit-field with the following structure:
// |unspecified|Filter|Addressing Mode| Normalized Coords|
// |31 6|5 4|3 1| 0|
// This structure corresponds to enum values of sampler properties
// defined in SPIR spec v1.2 and also opencl-c.h
unsigned AddressingMode = (0x0E & SamplerValue) >> 1;
unsigned FilterMode = (0x30 & SamplerValue) >> 4;
if (FilterMode != 1 && FilterMode != 2 &&
!S.getOpenCLOptions().isEnabled(
"cl_intel_device_side_avc_motion_estimation"))
S.Diag(Kind.getLocation(),
diag::warn_sampler_initializer_invalid_bits)
<< "Filter Mode";
if (AddressingMode > 4)
S.Diag(Kind.getLocation(),
diag::warn_sampler_initializer_invalid_bits)
<< "Addressing Mode";
}
// Cases 1a, 2a and 2b
// Insert cast from integer to sampler.
CurInit = S.ImpCastExprToType(Init, S.Context.OCLSamplerTy,
CK_IntToOCLSampler);
break;
}
case SK_OCLZeroOpaqueType: {
assert((Step->Type->isEventT() || Step->Type->isQueueT() ||
Step->Type->isOCLIntelSubgroupAVCType()) &&
"Wrong type for initialization of OpenCL opaque type.");
CurInit = S.ImpCastExprToType(CurInit.get(), Step->Type,
CK_ZeroToOCLOpaqueType,
CurInit.get()->getValueKind());
break;
}
}
}
// Check whether the initializer has a shorter lifetime than the initialized
// entity, and if not, either lifetime-extend or warn as appropriate.
if (auto *Init = CurInit.get())
S.checkInitializerLifetime(Entity, Init);
// Diagnose non-fatal problems with the completed initialization.
if (Entity.getKind() == InitializedEntity::EK_Member &&
cast<FieldDecl>(Entity.getDecl())->isBitField())
S.CheckBitFieldInitialization(Kind.getLocation(),
cast<FieldDecl>(Entity.getDecl()),
CurInit.get());
// Check for std::move on construction.
if (const Expr *E = CurInit.get()) {
CheckMoveOnConstruction(S, E,
Entity.getKind() == InitializedEntity::EK_Result);
}
return CurInit;
}
/// Somewhere within T there is an uninitialized reference subobject.
/// Dig it out and diagnose it.
static bool DiagnoseUninitializedReference(Sema &S, SourceLocation Loc,
QualType T) {
if (T->isReferenceType()) {
S.Diag(Loc, diag::err_reference_without_init)
<< T.getNonReferenceType();
return true;
}
CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
if (!RD || !RD->hasUninitializedReferenceMember())
return false;
for (const auto *FI : RD->fields()) {
if (FI->isUnnamedBitfield())
continue;
if (DiagnoseUninitializedReference(S, FI->getLocation(), FI->getType())) {
S.Diag(Loc, diag::note_value_initialization_here) << RD;
return true;
}
}
for (const auto &BI : RD->bases()) {
if (DiagnoseUninitializedReference(S, BI.getBeginLoc(), BI.getType())) {
S.Diag(Loc, diag::note_value_initialization_here) << RD;
return true;
}
}
return false;
}
//===----------------------------------------------------------------------===//
// Diagnose initialization failures
//===----------------------------------------------------------------------===//
/// Emit notes associated with an initialization that failed due to a
/// "simple" conversion failure.
static void emitBadConversionNotes(Sema &S, const InitializedEntity &entity,
Expr *op) {
QualType destType = entity.getType();
if (destType.getNonReferenceType()->isObjCObjectPointerType() &&
op->getType()->isObjCObjectPointerType()) {
// Emit a possible note about the conversion failing because the
// operand is a message send with a related result type.
S.EmitRelatedResultTypeNote(op);
// Emit a possible note about a return failing because we're
// expecting a related result type.
if (entity.getKind() == InitializedEntity::EK_Result)
S.EmitRelatedResultTypeNoteForReturn(destType);
}
QualType fromType = op->getType();
auto *fromDecl = fromType.getTypePtr()->getPointeeCXXRecordDecl();
auto *destDecl = destType.getTypePtr()->getPointeeCXXRecordDecl();
if (fromDecl && destDecl && fromDecl->getDeclKind() == Decl::CXXRecord &&
destDecl->getDeclKind() == Decl::CXXRecord &&
!fromDecl->isInvalidDecl() && !destDecl->isInvalidDecl() &&
!fromDecl->hasDefinition())
S.Diag(fromDecl->getLocation(), diag::note_forward_class_conversion)
<< S.getASTContext().getTagDeclType(fromDecl)
<< S.getASTContext().getTagDeclType(destDecl);
}
static void diagnoseListInit(Sema &S, const InitializedEntity &Entity,
InitListExpr *InitList) {
QualType DestType = Entity.getType();
QualType E;
if (S.getLangOpts().CPlusPlus11 && S.isStdInitializerList(DestType, &E)) {
QualType ArrayType = S.Context.getConstantArrayType(
E.withConst(),
llvm::APInt(S.Context.getTypeSize(S.Context.getSizeType()),
InitList->getNumInits()),
nullptr, clang::ArrayType::Normal, 0);
InitializedEntity HiddenArray =
InitializedEntity::InitializeTemporary(ArrayType);
return diagnoseListInit(S, HiddenArray, InitList);
}
if (DestType->isReferenceType()) {
// A list-initialization failure for a reference means that we tried to
// create a temporary of the inner type (per [dcl.init.list]p3.6) and the
// inner initialization failed.
QualType T = DestType->castAs<ReferenceType>()->getPointeeType();
diagnoseListInit(S, InitializedEntity::InitializeTemporary(T), InitList);
SourceLocation Loc = InitList->getBeginLoc();
if (auto *D = Entity.getDecl())
Loc = D->getLocation();
S.Diag(Loc, diag::note_in_reference_temporary_list_initializer) << T;
return;
}
InitListChecker DiagnoseInitList(S, Entity, InitList, DestType,
/*VerifyOnly=*/false,
/*TreatUnavailableAsInvalid=*/false);
assert(DiagnoseInitList.HadError() &&
"Inconsistent init list check result.");
}
bool InitializationSequence::Diagnose(Sema &S,
const InitializedEntity &Entity,
const InitializationKind &Kind,
ArrayRef<Expr *> Args) {
if (!Failed())
return false;
// When we want to diagnose only one element of a braced-init-list,
// we need to factor it out.
Expr *OnlyArg;
if (Args.size() == 1) {
auto *List = dyn_cast<InitListExpr>(Args[0]);
if (List && List->getNumInits() == 1)
OnlyArg = List->getInit(0);
else
OnlyArg = Args[0];
}
else
OnlyArg = nullptr;
QualType DestType = Entity.getType();
switch (Failure) {
case FK_TooManyInitsForReference:
// FIXME: Customize for the initialized entity?
if (Args.empty()) {
// Dig out the reference subobject which is uninitialized and diagnose it.
// If this is value-initialization, this could be nested some way within
// the target type.
assert(Kind.getKind() == InitializationKind::IK_Value ||
DestType->isReferenceType());
bool Diagnosed =
DiagnoseUninitializedReference(S, Kind.getLocation(), DestType);
assert(Diagnosed && "couldn't find uninitialized reference to diagnose");
(void)Diagnosed;
} else // FIXME: diagnostic below could be better!
S.Diag(Kind.getLocation(), diag::err_reference_has_multiple_inits)
<< SourceRange(Args.front()->getBeginLoc(), Args.back()->getEndLoc());
break;
case FK_ParenthesizedListInitForReference:
S.Diag(Kind.getLocation(), diag::err_list_init_in_parens)
<< 1 << Entity.getType() << Args[0]->getSourceRange();
break;
case FK_ArrayNeedsInitList:
S.Diag(Kind.getLocation(), diag::err_array_init_not_init_list) << 0;
break;
case FK_ArrayNeedsInitListOrStringLiteral:
S.Diag(Kind.getLocation(), diag::err_array_init_not_init_list) << 1;
break;
case FK_ArrayNeedsInitListOrWideStringLiteral:
S.Diag(Kind.getLocation(), diag::err_array_init_not_init_list) << 2;
break;
case FK_NarrowStringIntoWideCharArray:
S.Diag(Kind.getLocation(), diag::err_array_init_narrow_string_into_wchar);
break;
case FK_WideStringIntoCharArray:
S.Diag(Kind.getLocation(), diag::err_array_init_wide_string_into_char);
break;
case FK_IncompatWideStringIntoWideChar:
S.Diag(Kind.getLocation(),
diag::err_array_init_incompat_wide_string_into_wchar);
break;
case FK_PlainStringIntoUTF8Char:
S.Diag(Kind.getLocation(),
diag::err_array_init_plain_string_into_char8_t);
S.Diag(Args.front()->getBeginLoc(),
diag::note_array_init_plain_string_into_char8_t)
<< FixItHint::CreateInsertion(Args.front()->getBeginLoc(), "u8");
break;
case FK_UTF8StringIntoPlainChar:
S.Diag(Kind.getLocation(),
diag::err_array_init_utf8_string_into_char)
<< S.getLangOpts().CPlusPlus20;
break;
case FK_ArrayTypeMismatch:
case FK_NonConstantArrayInit:
S.Diag(Kind.getLocation(),
(Failure == FK_ArrayTypeMismatch
? diag::err_array_init_different_type
: diag::err_array_init_non_constant_array))
<< DestType.getNonReferenceType()
<< OnlyArg->getType()
<< Args[0]->getSourceRange();
break;
case FK_VariableLengthArrayHasInitializer:
S.Diag(Kind.getLocation(), diag::err_variable_object_no_init)
<< Args[0]->getSourceRange();
break;
case FK_AddressOfOverloadFailed: {
DeclAccessPair Found;
S.ResolveAddressOfOverloadedFunction(OnlyArg,
DestType.getNonReferenceType(),
true,
Found);
break;
}
case FK_AddressOfUnaddressableFunction: {
auto *FD = cast<FunctionDecl>(cast<DeclRefExpr>(OnlyArg)->getDecl());
S.checkAddressOfFunctionIsAvailable(FD, /*Complain=*/true,
OnlyArg->getBeginLoc());
break;
}
case FK_ReferenceInitOverloadFailed:
case FK_UserConversionOverloadFailed:
switch (FailedOverloadResult) {
case OR_Ambiguous:
FailedCandidateSet.NoteCandidates(
PartialDiagnosticAt(
Kind.getLocation(),
Failure == FK_UserConversionOverloadFailed
? (S.PDiag(diag::err_typecheck_ambiguous_condition)
<< OnlyArg->getType() << DestType
<< Args[0]->getSourceRange())
: (S.PDiag(diag::err_ref_init_ambiguous)
<< DestType << OnlyArg->getType()
<< Args[0]->getSourceRange())),
S, OCD_AmbiguousCandidates, Args);
break;
case OR_No_Viable_Function: {
auto Cands = FailedCandidateSet.CompleteCandidates(S, OCD_AllCandidates, Args);
if (!S.RequireCompleteType(Kind.getLocation(),
DestType.getNonReferenceType(),
diag::err_typecheck_nonviable_condition_incomplete,
OnlyArg->getType(), Args[0]->getSourceRange()))
S.Diag(Kind.getLocation(), diag::err_typecheck_nonviable_condition)
<< (Entity.getKind() == InitializedEntity::EK_Result)
<< OnlyArg->getType() << Args[0]->getSourceRange()
<< DestType.getNonReferenceType();
FailedCandidateSet.NoteCandidates(S, Args, Cands);
break;
}
case OR_Deleted: {
S.Diag(Kind.getLocation(), diag::err_typecheck_deleted_function)
<< OnlyArg->getType() << DestType.getNonReferenceType()
<< Args[0]->getSourceRange();
OverloadCandidateSet::iterator Best;
OverloadingResult Ovl
= FailedCandidateSet.BestViableFunction(S, Kind.getLocation(), Best);
if (Ovl == OR_Deleted) {
S.NoteDeletedFunction(Best->Function);
} else {
llvm_unreachable("Inconsistent overload resolution?");
}
break;
}
case OR_Success:
llvm_unreachable("Conversion did not fail!");
}
break;
case FK_NonConstLValueReferenceBindingToTemporary:
if (isa<InitListExpr>(Args[0])) {
S.Diag(Kind.getLocation(),
diag::err_lvalue_reference_bind_to_initlist)
<< DestType.getNonReferenceType().isVolatileQualified()
<< DestType.getNonReferenceType()
<< Args[0]->getSourceRange();
break;
}
LLVM_FALLTHROUGH;
case FK_NonConstLValueReferenceBindingToUnrelated:
S.Diag(Kind.getLocation(),
Failure == FK_NonConstLValueReferenceBindingToTemporary
? diag::err_lvalue_reference_bind_to_temporary
: diag::err_lvalue_reference_bind_to_unrelated)
<< DestType.getNonReferenceType().isVolatileQualified()
<< DestType.getNonReferenceType()
<< OnlyArg->getType()
<< Args[0]->getSourceRange();
break;
case FK_NonConstLValueReferenceBindingToBitfield: {
// We don't necessarily have an unambiguous source bit-field.
FieldDecl *BitField = Args[0]->getSourceBitField();
S.Diag(Kind.getLocation(), diag::err_reference_bind_to_bitfield)
<< DestType.isVolatileQualified()
<< (BitField ? BitField->getDeclName() : DeclarationName())
<< (BitField != nullptr)
<< Args[0]->getSourceRange();
if (BitField)
S.Diag(BitField->getLocation(), diag::note_bitfield_decl);
break;
}
case FK_NonConstLValueReferenceBindingToVectorElement:
S.Diag(Kind.getLocation(), diag::err_reference_bind_to_vector_element)
<< DestType.isVolatileQualified()
<< Args[0]->getSourceRange();
break;
case FK_NonConstLValueReferenceBindingToMatrixElement:
S.Diag(Kind.getLocation(), diag::err_reference_bind_to_matrix_element)
<< DestType.isVolatileQualified() << Args[0]->getSourceRange();
break;
case FK_RValueReferenceBindingToLValue:
S.Diag(Kind.getLocation(), diag::err_lvalue_to_rvalue_ref)
<< DestType.getNonReferenceType() << OnlyArg->getType()
<< Args[0]->getSourceRange();
break;
case FK_ReferenceAddrspaceMismatchTemporary:
S.Diag(Kind.getLocation(), diag::err_reference_bind_temporary_addrspace)
<< DestType << Args[0]->getSourceRange();
break;
case FK_ReferenceInitDropsQualifiers: {
QualType SourceType = OnlyArg->getType();
QualType NonRefType = DestType.getNonReferenceType();
Qualifiers DroppedQualifiers =
SourceType.getQualifiers() - NonRefType.getQualifiers();
if (!NonRefType.getQualifiers().isAddressSpaceSupersetOf(
SourceType.getQualifiers()))
S.Diag(Kind.getLocation(), diag::err_reference_bind_drops_quals)
<< NonRefType << SourceType << 1 /*addr space*/
<< Args[0]->getSourceRange();
else if (DroppedQualifiers.hasQualifiers())
S.Diag(Kind.getLocation(), diag::err_reference_bind_drops_quals)
<< NonRefType << SourceType << 0 /*cv quals*/
<< Qualifiers::fromCVRMask(DroppedQualifiers.getCVRQualifiers())
<< DroppedQualifiers.getCVRQualifiers() << Args[0]->getSourceRange();
else
// FIXME: Consider decomposing the type and explaining which qualifiers
// were dropped where, or on which level a 'const' is missing, etc.
S.Diag(Kind.getLocation(), diag::err_reference_bind_drops_quals)
<< NonRefType << SourceType << 2 /*incompatible quals*/
<< Args[0]->getSourceRange();
break;
}
case FK_ReferenceInitFailed:
S.Diag(Kind.getLocation(), diag::err_reference_bind_failed)
<< DestType.getNonReferenceType()
<< DestType.getNonReferenceType()->isIncompleteType()
<< OnlyArg->isLValue()
<< OnlyArg->getType()
<< Args[0]->getSourceRange();
emitBadConversionNotes(S, Entity, Args[0]);
break;
case FK_ConversionFailed: {
QualType FromType = OnlyArg->getType();
PartialDiagnostic PDiag = S.PDiag(diag::err_init_conversion_failed)
<< (int)Entity.getKind()
<< DestType
<< OnlyArg->isLValue()
<< FromType
<< Args[0]->getSourceRange();
S.HandleFunctionTypeMismatch(PDiag, FromType, DestType);
S.Diag(Kind.getLocation(), PDiag);
emitBadConversionNotes(S, Entity, Args[0]);
break;
}
case FK_ConversionFromPropertyFailed:
// No-op. This error has already been reported.
break;
case FK_TooManyInitsForScalar: {
SourceRange R;
auto *InitList = dyn_cast<InitListExpr>(Args[0]);
if (InitList && InitList->getNumInits() >= 1) {
R = SourceRange(InitList->getInit(0)->getEndLoc(), InitList->getEndLoc());
} else {
assert(Args.size() > 1 && "Expected multiple initializers!");
R = SourceRange(Args.front()->getEndLoc(), Args.back()->getEndLoc());
}
R.setBegin(S.getLocForEndOfToken(R.getBegin()));
if (Kind.isCStyleOrFunctionalCast())
S.Diag(Kind.getLocation(), diag::err_builtin_func_cast_more_than_one_arg)
<< R;
else
S.Diag(Kind.getLocation(), diag::err_excess_initializers)
<< /*scalar=*/2 << R;
break;
}
case FK_ParenthesizedListInitForScalar:
S.Diag(Kind.getLocation(), diag::err_list_init_in_parens)
<< 0 << Entity.getType() << Args[0]->getSourceRange();
break;
case FK_ReferenceBindingToInitList:
S.Diag(Kind.getLocation(), diag::err_reference_bind_init_list)
<< DestType.getNonReferenceType() << Args[0]->getSourceRange();
break;
case FK_InitListBadDestinationType:
S.Diag(Kind.getLocation(), diag::err_init_list_bad_dest_type)
<< (DestType->isRecordType()) << DestType << Args[0]->getSourceRange();
break;
case FK_ListConstructorOverloadFailed:
case FK_ConstructorOverloadFailed: {
SourceRange ArgsRange;
if (Args.size())
ArgsRange =
SourceRange(Args.front()->getBeginLoc(), Args.back()->getEndLoc());
if (Failure == FK_ListConstructorOverloadFailed) {
assert(Args.size() == 1 &&
"List construction from other than 1 argument.");
InitListExpr *InitList = cast<InitListExpr>(Args[0]);
Args = MultiExprArg(InitList->getInits(), InitList->getNumInits());
}
// FIXME: Using "DestType" for the entity we're printing is probably
// bad.
switch (FailedOverloadResult) {
case OR_Ambiguous:
FailedCandidateSet.NoteCandidates(
PartialDiagnosticAt(Kind.getLocation(),
S.PDiag(diag::err_ovl_ambiguous_init)
<< DestType << ArgsRange),
S, OCD_AmbiguousCandidates, Args);
break;
case OR_No_Viable_Function:
if (Kind.getKind() == InitializationKind::IK_Default &&
(Entity.getKind() == InitializedEntity::EK_Base ||
Entity.getKind() == InitializedEntity::EK_Member) &&
isa<CXXConstructorDecl>(S.CurContext)) {
// This is implicit default initialization of a member or
// base within a constructor. If no viable function was
// found, notify the user that they need to explicitly
// initialize this base/member.
CXXConstructorDecl *Constructor
= cast<CXXConstructorDecl>(S.CurContext);
const CXXRecordDecl *InheritedFrom = nullptr;
if (auto Inherited = Constructor->getInheritedConstructor())
InheritedFrom = Inherited.getShadowDecl()->getNominatedBaseClass();
if (Entity.getKind() == InitializedEntity::EK_Base) {
S.Diag(Kind.getLocation(), diag::err_missing_default_ctor)
<< (InheritedFrom ? 2 : Constructor->isImplicit() ? 1 : 0)
<< S.Context.getTypeDeclType(Constructor->getParent())
<< /*base=*/0
<< Entity.getType()
<< InheritedFrom;
RecordDecl *BaseDecl
= Entity.getBaseSpecifier()->getType()->castAs<RecordType>()
->getDecl();
S.Diag(BaseDecl->getLocation(), diag::note_previous_decl)
<< S.Context.getTagDeclType(BaseDecl);
} else {
S.Diag(Kind.getLocation(), diag::err_missing_default_ctor)
<< (InheritedFrom ? 2 : Constructor->isImplicit() ? 1 : 0)
<< S.Context.getTypeDeclType(Constructor->getParent())
<< /*member=*/1
<< Entity.getName()
<< InheritedFrom;
S.Diag(Entity.getDecl()->getLocation(),
diag::note_member_declared_at);
if (const RecordType *Record
= Entity.getType()->getAs<RecordType>())
S.Diag(Record->getDecl()->getLocation(),
diag::note_previous_decl)
<< S.Context.getTagDeclType(Record->getDecl());
}
break;
}
FailedCandidateSet.NoteCandidates(
PartialDiagnosticAt(
Kind.getLocation(),
S.PDiag(diag::err_ovl_no_viable_function_in_init)
<< DestType << ArgsRange),
S, OCD_AllCandidates, Args);
break;
case OR_Deleted: {
OverloadCandidateSet::iterator Best;
OverloadingResult Ovl
= FailedCandidateSet.BestViableFunction(S, Kind.getLocation(), Best);
if (Ovl != OR_Deleted) {
S.Diag(Kind.getLocation(), diag::err_ovl_deleted_init)
<< DestType << ArgsRange;
llvm_unreachable("Inconsistent overload resolution?");
break;
}
// If this is a defaulted or implicitly-declared function, then
// it was implicitly deleted. Make it clear that the deletion was
// implicit.
if (S.isImplicitlyDeleted(Best->Function))
S.Diag(Kind.getLocation(), diag::err_ovl_deleted_special_init)
<< S.getSpecialMember(cast<CXXMethodDecl>(Best->Function))
<< DestType << ArgsRange;
else
S.Diag(Kind.getLocation(), diag::err_ovl_deleted_init)
<< DestType << ArgsRange;
S.NoteDeletedFunction(Best->Function);
break;
}
case OR_Success:
llvm_unreachable("Conversion did not fail!");
}
}
break;
case FK_DefaultInitOfConst:
if (Entity.getKind() == InitializedEntity::EK_Member &&
isa<CXXConstructorDecl>(S.CurContext)) {
// This is implicit default-initialization of a const member in
// a constructor. Complain that it needs to be explicitly
// initialized.
CXXConstructorDecl *Constructor = cast<CXXConstructorDecl>(S.CurContext);
S.Diag(Kind.getLocation(), diag::err_uninitialized_member_in_ctor)
<< (Constructor->getInheritedConstructor() ? 2 :
Constructor->isImplicit() ? 1 : 0)
<< S.Context.getTypeDeclType(Constructor->getParent())
<< /*const=*/1
<< Entity.getName();
S.Diag(Entity.getDecl()->getLocation(), diag::note_previous_decl)
<< Entity.getName();
} else {
S.Diag(Kind.getLocation(), diag::err_default_init_const)
<< DestType << (bool)DestType->getAs<RecordType>();
}
break;
case FK_Incomplete:
S.RequireCompleteType(Kind.getLocation(), FailedIncompleteType,
diag::err_init_incomplete_type);
break;
case FK_ListInitializationFailed: {
// Run the init list checker again to emit diagnostics.
InitListExpr *InitList = cast<InitListExpr>(Args[0]);
diagnoseListInit(S, Entity, InitList);
break;
}
case FK_PlaceholderType: {
// FIXME: Already diagnosed!
break;
}
case FK_ExplicitConstructor: {
S.Diag(Kind.getLocation(), diag::err_selected_explicit_constructor)
<< Args[0]->getSourceRange();
OverloadCandidateSet::iterator Best;
OverloadingResult Ovl
= FailedCandidateSet.BestViableFunction(S, Kind.getLocation(), Best);
(void)Ovl;
assert(Ovl == OR_Success && "Inconsistent overload resolution");
CXXConstructorDecl *CtorDecl = cast<CXXConstructorDecl>(Best->Function);
S.Diag(CtorDecl->getLocation(),
diag::note_explicit_ctor_deduction_guide_here) << false;
break;
}
}
PrintInitLocationNote(S, Entity);
return true;
}
void InitializationSequence::dump(raw_ostream &OS) const {
switch (SequenceKind) {
case FailedSequence: {
OS << "Failed sequence: ";
switch (Failure) {
case FK_TooManyInitsForReference:
OS << "too many initializers for reference";
break;
case FK_ParenthesizedListInitForReference:
OS << "parenthesized list init for reference";
break;
case FK_ArrayNeedsInitList:
OS << "array requires initializer list";
break;
case FK_AddressOfUnaddressableFunction:
OS << "address of unaddressable function was taken";
break;
case FK_ArrayNeedsInitListOrStringLiteral:
OS << "array requires initializer list or string literal";
break;
case FK_ArrayNeedsInitListOrWideStringLiteral:
OS << "array requires initializer list or wide string literal";
break;
case FK_NarrowStringIntoWideCharArray:
OS << "narrow string into wide char array";
break;
case FK_WideStringIntoCharArray:
OS << "wide string into char array";
break;
case FK_IncompatWideStringIntoWideChar:
OS << "incompatible wide string into wide char array";
break;
case FK_PlainStringIntoUTF8Char:
OS << "plain string literal into char8_t array";
break;
case FK_UTF8StringIntoPlainChar:
OS << "u8 string literal into char array";
break;
case FK_ArrayTypeMismatch:
OS << "array type mismatch";
break;
case FK_NonConstantArrayInit:
OS << "non-constant array initializer";
break;
case FK_AddressOfOverloadFailed:
OS << "address of overloaded function failed";
break;
case FK_ReferenceInitOverloadFailed:
OS << "overload resolution for reference initialization failed";
break;
case FK_NonConstLValueReferenceBindingToTemporary:
OS << "non-const lvalue reference bound to temporary";
break;
case FK_NonConstLValueReferenceBindingToBitfield:
OS << "non-const lvalue reference bound to bit-field";
break;
case FK_NonConstLValueReferenceBindingToVectorElement:
OS << "non-const lvalue reference bound to vector element";
break;
case FK_NonConstLValueReferenceBindingToMatrixElement:
OS << "non-const lvalue reference bound to matrix element";
break;
case FK_NonConstLValueReferenceBindingToUnrelated:
OS << "non-const lvalue reference bound to unrelated type";
break;
case FK_RValueReferenceBindingToLValue:
OS << "rvalue reference bound to an lvalue";
break;
case FK_ReferenceInitDropsQualifiers:
OS << "reference initialization drops qualifiers";
break;
case FK_ReferenceAddrspaceMismatchTemporary:
OS << "reference with mismatching address space bound to temporary";
break;
case FK_ReferenceInitFailed:
OS << "reference initialization failed";
break;
case FK_ConversionFailed:
OS << "conversion failed";
break;
case FK_ConversionFromPropertyFailed:
OS << "conversion from property failed";
break;
case FK_TooManyInitsForScalar:
OS << "too many initializers for scalar";
break;
case FK_ParenthesizedListInitForScalar:
OS << "parenthesized list init for reference";
break;
case FK_ReferenceBindingToInitList:
OS << "referencing binding to initializer list";
break;
case FK_InitListBadDestinationType:
OS << "initializer list for non-aggregate, non-scalar type";
break;
case FK_UserConversionOverloadFailed:
OS << "overloading failed for user-defined conversion";
break;
case FK_ConstructorOverloadFailed:
OS << "constructor overloading failed";
break;
case FK_DefaultInitOfConst:
OS << "default initialization of a const variable";
break;
case FK_Incomplete:
OS << "initialization of incomplete type";
break;
case FK_ListInitializationFailed:
OS << "list initialization checker failure";
break;
case FK_VariableLengthArrayHasInitializer:
OS << "variable length array has an initializer";
break;
case FK_PlaceholderType:
OS << "initializer expression isn't contextually valid";
break;
case FK_ListConstructorOverloadFailed:
OS << "list constructor overloading failed";
break;
case FK_ExplicitConstructor:
OS << "list copy initialization chose explicit constructor";
break;
}
OS << '\n';
return;
}
case DependentSequence:
OS << "Dependent sequence\n";
return;
case NormalSequence:
OS << "Normal sequence: ";
break;
}
for (step_iterator S = step_begin(), SEnd = step_end(); S != SEnd; ++S) {
if (S != step_begin()) {
OS << " -> ";
}
switch (S->Kind) {
case SK_ResolveAddressOfOverloadedFunction:
OS << "resolve address of overloaded function";
break;
case SK_CastDerivedToBaseRValue:
OS << "derived-to-base (rvalue)";
break;
case SK_CastDerivedToBaseXValue:
OS << "derived-to-base (xvalue)";
break;
case SK_CastDerivedToBaseLValue:
OS << "derived-to-base (lvalue)";
break;
case SK_BindReference:
OS << "bind reference to lvalue";
break;
case SK_BindReferenceToTemporary:
OS << "bind reference to a temporary";
break;
case SK_FinalCopy:
OS << "final copy in class direct-initialization";
break;
case SK_ExtraneousCopyToTemporary:
OS << "extraneous C++03 copy to temporary";
break;
case SK_UserConversion:
OS << "user-defined conversion via " << *S->Function.Function;
break;
case SK_QualificationConversionRValue:
OS << "qualification conversion (rvalue)";
break;
case SK_QualificationConversionXValue:
OS << "qualification conversion (xvalue)";
break;
case SK_QualificationConversionLValue:
OS << "qualification conversion (lvalue)";
break;
case SK_FunctionReferenceConversion:
OS << "function reference conversion";
break;
case SK_AtomicConversion:
OS << "non-atomic-to-atomic conversion";
break;
case SK_ConversionSequence:
OS << "implicit conversion sequence (";
S->ICS->dump(); // FIXME: use OS
OS << ")";
break;
case SK_ConversionSequenceNoNarrowing:
OS << "implicit conversion sequence with narrowing prohibited (";
S->ICS->dump(); // FIXME: use OS
OS << ")";
break;
case SK_ListInitialization:
OS << "list aggregate initialization";
break;
case SK_UnwrapInitList:
OS << "unwrap reference initializer list";
break;
case SK_RewrapInitList:
OS << "rewrap reference initializer list";
break;
case SK_ConstructorInitialization:
OS << "constructor initialization";
break;
case SK_ConstructorInitializationFromList:
OS << "list initialization via constructor";
break;
case SK_ZeroInitialization:
OS << "zero initialization";
break;
case SK_CAssignment:
OS << "C assignment";
break;
case SK_StringInit:
OS << "string initialization";
break;
case SK_ObjCObjectConversion:
OS << "Objective-C object conversion";
break;
case SK_ArrayLoopIndex:
OS << "indexing for array initialization loop";
break;
case SK_ArrayLoopInit:
OS << "array initialization loop";
break;
case SK_ArrayInit:
OS << "array initialization";
break;
case SK_GNUArrayInit:
OS << "array initialization (GNU extension)";
break;
case SK_ParenthesizedArrayInit:
OS << "parenthesized array initialization";
break;
case SK_PassByIndirectCopyRestore:
OS << "pass by indirect copy and restore";
break;
case SK_PassByIndirectRestore:
OS << "pass by indirect restore";
break;
case SK_ProduceObjCObject:
OS << "Objective-C object retension";
break;
case SK_StdInitializerList:
OS << "std::initializer_list from initializer list";
break;
case SK_StdInitializerListConstructorCall:
OS << "list initialization from std::initializer_list";
break;
case SK_OCLSamplerInit:
OS << "OpenCL sampler_t from integer constant";
break;
case SK_OCLZeroOpaqueType:
OS << "OpenCL opaque type from zero";
break;
}
OS << " [" << S->Type.getAsString() << ']';
}
OS << '\n';
}
void InitializationSequence::dump() const {
dump(llvm::errs());
}
static bool NarrowingErrs(const LangOptions &L) {
return L.CPlusPlus11 &&
(!L.MicrosoftExt || L.isCompatibleWithMSVC(LangOptions::MSVC2015));
}
static void DiagnoseNarrowingInInitList(Sema &S,
const ImplicitConversionSequence &ICS,
QualType PreNarrowingType,
QualType EntityType,
const Expr *PostInit) {
const StandardConversionSequence *SCS = nullptr;
switch (ICS.getKind()) {
case ImplicitConversionSequence::StandardConversion:
SCS = &ICS.Standard;
break;
case ImplicitConversionSequence::UserDefinedConversion:
SCS = &ICS.UserDefined.After;
break;
case ImplicitConversionSequence::AmbiguousConversion:
case ImplicitConversionSequence::EllipsisConversion:
case ImplicitConversionSequence::BadConversion:
return;
}
// C++11 [dcl.init.list]p7: Check whether this is a narrowing conversion.
APValue ConstantValue;
QualType ConstantType;
switch (SCS->getNarrowingKind(S.Context, PostInit, ConstantValue,
ConstantType)) {
case NK_Not_Narrowing:
case NK_Dependent_Narrowing:
// No narrowing occurred.
return;
case NK_Type_Narrowing:
// This was a floating-to-integer conversion, which is always considered a
// narrowing conversion even if the value is a constant and can be
// represented exactly as an integer.
S.Diag(PostInit->getBeginLoc(), NarrowingErrs(S.getLangOpts())
? diag::ext_init_list_type_narrowing
: diag::warn_init_list_type_narrowing)
<< PostInit->getSourceRange()
<< PreNarrowingType.getLocalUnqualifiedType()
<< EntityType.getLocalUnqualifiedType();
break;
case NK_Constant_Narrowing:
// A constant value was narrowed.
S.Diag(PostInit->getBeginLoc(),
NarrowingErrs(S.getLangOpts())
? diag::ext_init_list_constant_narrowing
: diag::warn_init_list_constant_narrowing)
<< PostInit->getSourceRange()
<< ConstantValue.getAsString(S.getASTContext(), ConstantType)
<< EntityType.getLocalUnqualifiedType();
break;
case NK_Variable_Narrowing:
// A variable's value may have been narrowed.
S.Diag(PostInit->getBeginLoc(),
NarrowingErrs(S.getLangOpts())
? diag::ext_init_list_variable_narrowing
: diag::warn_init_list_variable_narrowing)
<< PostInit->getSourceRange()
<< PreNarrowingType.getLocalUnqualifiedType()
<< EntityType.getLocalUnqualifiedType();
break;
}
SmallString<128> StaticCast;
llvm::raw_svector_ostream OS(StaticCast);
OS << "static_cast<";
if (const TypedefType *TT = EntityType->getAs<TypedefType>()) {
// It's important to use the typedef's name if there is one so that the
// fixit doesn't break code using types like int64_t.
//
// FIXME: This will break if the typedef requires qualification. But
// getQualifiedNameAsString() includes non-machine-parsable components.
OS << *TT->getDecl();
} else if (const BuiltinType *BT = EntityType->getAs<BuiltinType>())
OS << BT->getName(S.getLangOpts());
else {
// Oops, we didn't find the actual type of the variable. Don't emit a fixit
// with a broken cast.
return;
}
OS << ">(";
S.Diag(PostInit->getBeginLoc(), diag::note_init_list_narrowing_silence)
<< PostInit->getSourceRange()
<< FixItHint::CreateInsertion(PostInit->getBeginLoc(), OS.str())
<< FixItHint::CreateInsertion(
S.getLocForEndOfToken(PostInit->getEndLoc()), ")");
}
//===----------------------------------------------------------------------===//
// Initialization helper functions
//===----------------------------------------------------------------------===//
bool
Sema::CanPerformCopyInitialization(const InitializedEntity &Entity,
ExprResult Init) {
if (Init.isInvalid())
return false;
Expr *InitE = Init.get();
assert(InitE && "No initialization expression");
InitializationKind Kind =
InitializationKind::CreateCopy(InitE->getBeginLoc(), SourceLocation());
InitializationSequence Seq(*this, Entity, Kind, InitE);
return !Seq.Failed();
}
ExprResult
Sema::PerformCopyInitialization(const InitializedEntity &Entity,
SourceLocation EqualLoc,
ExprResult Init,
bool TopLevelOfInitList,
bool AllowExplicit) {
if (Init.isInvalid())
return ExprError();
Expr *InitE = Init.get();
assert(InitE && "No initialization expression?");
if (EqualLoc.isInvalid())
EqualLoc = InitE->getBeginLoc();
InitializationKind Kind = InitializationKind::CreateCopy(
InitE->getBeginLoc(), EqualLoc, AllowExplicit);
InitializationSequence Seq(*this, Entity, Kind, InitE, TopLevelOfInitList);
// Prevent infinite recursion when performing parameter copy-initialization.
const bool ShouldTrackCopy =
Entity.isParameterKind() && Seq.isConstructorInitialization();
if (ShouldTrackCopy) {
if (llvm::find(CurrentParameterCopyTypes, Entity.getType()) !=
CurrentParameterCopyTypes.end()) {
Seq.SetOverloadFailure(
InitializationSequence::FK_ConstructorOverloadFailed,
OR_No_Viable_Function);
// Try to give a meaningful diagnostic note for the problematic
// constructor.
const auto LastStep = Seq.step_end() - 1;
assert(LastStep->Kind ==
InitializationSequence::SK_ConstructorInitialization);
const FunctionDecl *Function = LastStep->Function.Function;
auto Candidate =
llvm::find_if(Seq.getFailedCandidateSet(),
[Function](const OverloadCandidate &Candidate) -> bool {
return Candidate.Viable &&
Candidate.Function == Function &&
Candidate.Conversions.size() > 0;
});
if (Candidate != Seq.getFailedCandidateSet().end() &&
Function->getNumParams() > 0) {
Candidate->Viable = false;
Candidate->FailureKind = ovl_fail_bad_conversion;
Candidate->Conversions[0].setBad(BadConversionSequence::no_conversion,
InitE,
Function->getParamDecl(0)->getType());
}
}
CurrentParameterCopyTypes.push_back(Entity.getType());
}
ExprResult Result = Seq.Perform(*this, Entity, Kind, InitE);
if (ShouldTrackCopy)
CurrentParameterCopyTypes.pop_back();
return Result;
}
/// Determine whether RD is, or is derived from, a specialization of CTD.
static bool isOrIsDerivedFromSpecializationOf(CXXRecordDecl *RD,
ClassTemplateDecl *CTD) {
auto NotSpecialization = [&] (const CXXRecordDecl *Candidate) {
auto *CTSD = dyn_cast<ClassTemplateSpecializationDecl>(Candidate);
return !CTSD || !declaresSameEntity(CTSD->getSpecializedTemplate(), CTD);
};
return !(NotSpecialization(RD) && RD->forallBases(NotSpecialization));
}
QualType Sema::DeduceTemplateSpecializationFromInitializer(
TypeSourceInfo *TSInfo, const InitializedEntity &Entity,
const InitializationKind &Kind, MultiExprArg Inits) {
auto *DeducedTST = dyn_cast<DeducedTemplateSpecializationType>(
TSInfo->getType()->getContainedDeducedType());
assert(DeducedTST && "not a deduced template specialization type");
auto TemplateName = DeducedTST->getTemplateName();
if (TemplateName.isDependent())
return SubstAutoType(TSInfo->getType(), Context.DependentTy);
// We can only perform deduction for class templates.
auto *Template =
dyn_cast_or_null<ClassTemplateDecl>(TemplateName.getAsTemplateDecl());
if (!Template) {
Diag(Kind.getLocation(),
diag::err_deduced_non_class_template_specialization_type)
<< (int)getTemplateNameKindForDiagnostics(TemplateName) << TemplateName;
if (auto *TD = TemplateName.getAsTemplateDecl())
Diag(TD->getLocation(), diag::note_template_decl_here);
return QualType();
}
// Can't deduce from dependent arguments.
if (Expr::hasAnyTypeDependentArguments(Inits)) {
Diag(TSInfo->getTypeLoc().getBeginLoc(),
diag::warn_cxx14_compat_class_template_argument_deduction)
<< TSInfo->getTypeLoc().getSourceRange() << 0;
return SubstAutoType(TSInfo->getType(), Context.DependentTy);
}
// FIXME: Perform "exact type" matching first, per CWG discussion?
// Or implement this via an implied 'T(T) -> T' deduction guide?
// FIXME: Do we need/want a std::initializer_list<T> special case?
// Look up deduction guides, including those synthesized from constructors.
//
// C++1z [over.match.class.deduct]p1:
// A set of functions and function templates is formed comprising:
// - For each constructor of the class template designated by the
// template-name, a function template [...]
// - For each deduction-guide, a function or function template [...]
DeclarationNameInfo NameInfo(
Context.DeclarationNames.getCXXDeductionGuideName(Template),
TSInfo->getTypeLoc().getEndLoc());
LookupResult Guides(*this, NameInfo, LookupOrdinaryName);
LookupQualifiedName(Guides, Template->getDeclContext());
// FIXME: Do not diagnose inaccessible deduction guides. The standard isn't
// clear on this, but they're not found by name so access does not apply.
Guides.suppressDiagnostics();
// Figure out if this is list-initialization.
InitListExpr *ListInit =
(Inits.size() == 1 && Kind.getKind() != InitializationKind::IK_Direct)
? dyn_cast<InitListExpr>(Inits[0])
: nullptr;
// C++1z [over.match.class.deduct]p1:
// Initialization and overload resolution are performed as described in
// [dcl.init] and [over.match.ctor], [over.match.copy], or [over.match.list]
// (as appropriate for the type of initialization performed) for an object
// of a hypothetical class type, where the selected functions and function
// templates are considered to be the constructors of that class type
//
// Since we know we're initializing a class type of a type unrelated to that
// of the initializer, this reduces to something fairly reasonable.
OverloadCandidateSet Candidates(Kind.getLocation(),
OverloadCandidateSet::CSK_Normal);
OverloadCandidateSet::iterator Best;
bool HasAnyDeductionGuide = false;
bool AllowExplicit = !Kind.isCopyInit() || ListInit;
auto tryToResolveOverload =
[&](bool OnlyListConstructors) -> OverloadingResult {
Candidates.clear(OverloadCandidateSet::CSK_Normal);
HasAnyDeductionGuide = false;
for (auto I = Guides.begin(), E = Guides.end(); I != E; ++I) {
NamedDecl *D = (*I)->getUnderlyingDecl();
if (D->isInvalidDecl())
continue;
auto *TD = dyn_cast<FunctionTemplateDecl>(D);
auto *GD = dyn_cast_or_null<CXXDeductionGuideDecl>(
TD ? TD->getTemplatedDecl() : dyn_cast<FunctionDecl>(D));
if (!GD)
continue;
if (!GD->isImplicit())
HasAnyDeductionGuide = true;
// C++ [over.match.ctor]p1: (non-list copy-initialization from non-class)
// For copy-initialization, the candidate functions are all the
// converting constructors (12.3.1) of that class.
// C++ [over.match.copy]p1: (non-list copy-initialization from class)
// The converting constructors of T are candidate functions.
if (!AllowExplicit) {
// Overload resolution checks whether the deduction guide is declared
// explicit for us.
// When looking for a converting constructor, deduction guides that
// could never be called with one argument are not interesting to
// check or note.
if (GD->getMinRequiredArguments() > 1 ||
(GD->getNumParams() == 0 && !GD->isVariadic()))
continue;
}
// C++ [over.match.list]p1.1: (first phase list initialization)
// Initially, the candidate functions are the initializer-list
// constructors of the class T
if (OnlyListConstructors && !isInitListConstructor(GD))
continue;
// C++ [over.match.list]p1.2: (second phase list initialization)
// the candidate functions are all the constructors of the class T
// C++ [over.match.ctor]p1: (all other cases)
// the candidate functions are all the constructors of the class of
// the object being initialized
// C++ [over.best.ics]p4:
// When [...] the constructor [...] is a candidate by
// - [over.match.copy] (in all cases)
// FIXME: The "second phase of [over.match.list] case can also
// theoretically happen here, but it's not clear whether we can
// ever have a parameter of the right type.
bool SuppressUserConversions = Kind.isCopyInit();
if (TD)
AddTemplateOverloadCandidate(TD, I.getPair(), /*ExplicitArgs*/ nullptr,
Inits, Candidates, SuppressUserConversions,
/*PartialOverloading*/ false,
AllowExplicit);
else
AddOverloadCandidate(GD, I.getPair(), Inits, Candidates,
SuppressUserConversions,
/*PartialOverloading*/ false, AllowExplicit);
}
return Candidates.BestViableFunction(*this, Kind.getLocation(), Best);
};
OverloadingResult Result = OR_No_Viable_Function;
// C++11 [over.match.list]p1, per DR1467: for list-initialization, first
// try initializer-list constructors.
if (ListInit) {
bool TryListConstructors = true;
// Try list constructors unless the list is empty and the class has one or
// more default constructors, in which case those constructors win.
if (!ListInit->getNumInits()) {
for (NamedDecl *D : Guides) {
auto *FD = dyn_cast<FunctionDecl>(D->getUnderlyingDecl());
if (FD && FD->getMinRequiredArguments() == 0) {
TryListConstructors = false;
break;
}
}
} else if (ListInit->getNumInits() == 1) {
// C++ [over.match.class.deduct]:
// As an exception, the first phase in [over.match.list] (considering
// initializer-list constructors) is omitted if the initializer list
// consists of a single expression of type cv U, where U is a
// specialization of C or a class derived from a specialization of C.
Expr *E = ListInit->getInit(0);
auto *RD = E->getType()->getAsCXXRecordDecl();
if (!isa<InitListExpr>(E) && RD &&
isCompleteType(Kind.getLocation(), E->getType()) &&
isOrIsDerivedFromSpecializationOf(RD, Template))
TryListConstructors = false;
}
if (TryListConstructors)
Result = tryToResolveOverload(/*OnlyListConstructor*/true);
// Then unwrap the initializer list and try again considering all
// constructors.
Inits = MultiExprArg(ListInit->getInits(), ListInit->getNumInits());
}
// If list-initialization fails, or if we're doing any other kind of
// initialization, we (eventually) consider constructors.
if (Result == OR_No_Viable_Function)
Result = tryToResolveOverload(/*OnlyListConstructor*/false);
switch (Result) {
case OR_Ambiguous:
// FIXME: For list-initialization candidates, it'd usually be better to
// list why they were not viable when given the initializer list itself as
// an argument.
Candidates.NoteCandidates(
PartialDiagnosticAt(
Kind.getLocation(),
PDiag(diag::err_deduced_class_template_ctor_ambiguous)
<< TemplateName),
*this, OCD_AmbiguousCandidates, Inits);
return QualType();
case OR_No_Viable_Function: {
CXXRecordDecl *Primary =
cast<ClassTemplateDecl>(Template)->getTemplatedDecl();
bool Complete =
isCompleteType(Kind.getLocation(), Context.getTypeDeclType(Primary));
Candidates.NoteCandidates(
PartialDiagnosticAt(
Kind.getLocation(),
PDiag(Complete ? diag::err_deduced_class_template_ctor_no_viable
: diag::err_deduced_class_template_incomplete)
<< TemplateName << !Guides.empty()),
*this, OCD_AllCandidates, Inits);
return QualType();
}
case OR_Deleted: {
Diag(Kind.getLocation(), diag::err_deduced_class_template_deleted)
<< TemplateName;
NoteDeletedFunction(Best->Function);
return QualType();
}
case OR_Success:
// C++ [over.match.list]p1:
// In copy-list-initialization, if an explicit constructor is chosen, the
// initialization is ill-formed.
if (Kind.isCopyInit() && ListInit &&
cast<CXXDeductionGuideDecl>(Best->Function)->isExplicit()) {
bool IsDeductionGuide = !Best->Function->isImplicit();
Diag(Kind.getLocation(), diag::err_deduced_class_template_explicit)
<< TemplateName << IsDeductionGuide;
Diag(Best->Function->getLocation(),
diag::note_explicit_ctor_deduction_guide_here)
<< IsDeductionGuide;
return QualType();
}
// Make sure we didn't select an unusable deduction guide, and mark it
// as referenced.
DiagnoseUseOfDecl(Best->Function, Kind.getLocation());
MarkFunctionReferenced(Kind.getLocation(), Best->Function);
break;
}
// C++ [dcl.type.class.deduct]p1:
// The placeholder is replaced by the return type of the function selected
// by overload resolution for class template deduction.
QualType DeducedType =
SubstAutoType(TSInfo->getType(), Best->Function->getReturnType());
Diag(TSInfo->getTypeLoc().getBeginLoc(),
diag::warn_cxx14_compat_class_template_argument_deduction)
<< TSInfo->getTypeLoc().getSourceRange() << 1 << DeducedType;
// Warn if CTAD was used on a type that does not have any user-defined
// deduction guides.
if (!HasAnyDeductionGuide) {
Diag(TSInfo->getTypeLoc().getBeginLoc(),
diag::warn_ctad_maybe_unsupported)
<< TemplateName;
Diag(Template->getLocation(), diag::note_suppress_ctad_maybe_unsupported);
}
return DeducedType;
}
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