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

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//===--- SemaInit.cpp - Semantic Analysis for Initializers ----------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements semantic analysis for initializers. The entry
// point is Sema::CheckInitList(), but all of the work is performed
// within the InitListChecker class.
//
//===----------------------------------------------------------------------===//
#include "Sema.h"
#include "clang/Parse/Designator.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Expr.h"
#include <map>
using namespace clang;
/// @brief 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 the "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.
namespace clang {
class InitListChecker {
Sema *SemaRef;
bool hadError;
std::map<InitListExpr *, InitListExpr *> SyntacticToSemantic;
InitListExpr *FullyStructuredList;
void CheckImplicitInitList(InitListExpr *ParentIList, QualType T,
unsigned &Index, InitListExpr *StructuredList,
unsigned &StructuredIndex);
void CheckExplicitInitList(InitListExpr *IList, QualType &T,
unsigned &Index, InitListExpr *StructuredList,
unsigned &StructuredIndex);
void CheckListElementTypes(InitListExpr *IList, QualType &DeclType,
bool SubobjectIsDesignatorContext,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex);
void CheckSubElementType(InitListExpr *IList, QualType ElemType,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex);
// FIXME: Does DeclType need to be a reference type?
void CheckScalarType(InitListExpr *IList, QualType &DeclType,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex);
void CheckVectorType(InitListExpr *IList, QualType DeclType, unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex);
void CheckStructUnionTypes(InitListExpr *IList, QualType DeclType,
RecordDecl::field_iterator Field,
bool SubobjectIsDesignatorContext, unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex);
void CheckArrayType(InitListExpr *IList, QualType &DeclType,
llvm::APSInt elementIndex,
bool SubobjectIsDesignatorContext, unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex);
bool CheckDesignatedInitializer(InitListExpr *IList, DesignatedInitExpr *DIE,
DesignatedInitExpr::designators_iterator D,
QualType &CurrentObjectType,
RecordDecl::field_iterator *NextField,
llvm::APSInt *NextElementIndex,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex,
bool FinishSubobjectInit = true);
InitListExpr *getStructuredSubobjectInit(InitListExpr *IList, unsigned Index,
QualType CurrentObjectType,
InitListExpr *StructuredList,
unsigned StructuredIndex,
SourceRange InitRange);
void UpdateStructuredListElement(InitListExpr *StructuredList,
unsigned &StructuredIndex,
Expr *expr);
int numArrayElements(QualType DeclType);
int numStructUnionElements(QualType DeclType);
public:
InitListChecker(Sema *S, InitListExpr *IL, QualType &T);
bool HadError() { return hadError; }
// @brief Retrieves the fully-structured initializer list used for
// semantic analysis and code generation.
InitListExpr *getFullyStructuredList() const { return FullyStructuredList; }
};
}
/// Recursively replaces NULL values within the given initializer list
/// with expressions that perform value-initialization of the
/// appropriate type.
static void fillInValueInitializations(ASTContext &Context, InitListExpr *ILE) {
assert((ILE->getType() != Context.VoidTy) && "Should not have void type");
if (const RecordType *RType = ILE->getType()->getAsRecordType()) {
unsigned Init = 0, NumInits = ILE->getNumInits();
for (RecordDecl::field_iterator Field = RType->getDecl()->field_begin(),
FieldEnd = RType->getDecl()->field_end();
Field != FieldEnd; ++Field) {
if (Field->isUnnamedBitfield())
continue;
if (Init >= NumInits)
break;
// FIXME: Check for fields with reference type in C++?
if (!ILE->getInit(Init))
ILE->setInit(Init,
new (Context) ImplicitValueInitExpr(Field->getType()));
else if (InitListExpr *InnerILE
= dyn_cast<InitListExpr>(ILE->getInit(Init)))
fillInValueInitializations(Context, InnerILE);
++Init;
}
return;
}
QualType ElementType;
if (const ArrayType *AType = Context.getAsArrayType(ILE->getType()))
ElementType = AType->getElementType();
else if (const VectorType *VType = ILE->getType()->getAsVectorType())
ElementType = VType->getElementType();
else
ElementType = ILE->getType();
for (unsigned Init = 0, NumInits = ILE->getNumInits(); Init != NumInits;
++Init) {
if (!ILE->getInit(Init))
ILE->setInit(Init, new (Context) ImplicitValueInitExpr(ElementType));
else if (InitListExpr *InnerILE =dyn_cast<InitListExpr>(ILE->getInit(Init)))
fillInValueInitializations(Context, InnerILE);
}
}
InitListChecker::InitListChecker(Sema *S, InitListExpr *IL, QualType &T) {
hadError = false;
SemaRef = S;
unsigned newIndex = 0;
unsigned newStructuredIndex = 0;
FullyStructuredList
= getStructuredSubobjectInit(IL, newIndex, T, 0, 0, SourceRange());
CheckExplicitInitList(IL, T, newIndex, FullyStructuredList, newStructuredIndex);
if (!hadError) {
fillInValueInitializations(SemaRef->Context, FullyStructuredList);
}
}
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->getAsRecordType()->getDecl();
int InitializableMembers = 0;
for (RecordDecl::field_iterator Field = structDecl->field_begin(),
FieldEnd = structDecl->field_end();
Field != FieldEnd; ++Field) {
if ((*Field)->getIdentifier() || !(*Field)->isBitField())
++InitializableMembers;
}
if (structDecl->isUnion())
return std::min(InitializableMembers, 1);
return InitializableMembers - structDecl->hasFlexibleArrayMember();
}
void InitListChecker::CheckImplicitInitList(InitListExpr *ParentIList,
QualType T, unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex) {
int maxElements = 0;
if (T->isArrayType())
maxElements = numArrayElements(T);
else if (T->isStructureType() || T->isUnionType())
maxElements = numStructUnionElements(T);
else if (T->isVectorType())
maxElements = T->getAsVectorType()->getNumElements();
else
assert(0 && "CheckImplicitInitList(): Illegal type");
// FIXME: Perhaps we should move this warning elsewhere?
if (maxElements == 0) {
SemaRef->Diag(ParentIList->getInit(Index)->getLocStart(),
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,
ParentIList->getInit(Index)->getSourceRange());
unsigned StructuredSubobjectInitIndex = 0;
// Check the element types and build the structural subobject.
CheckListElementTypes(ParentIList, T, false, Index,
StructuredSubobjectInitList,
StructuredSubobjectInitIndex);
}
void InitListChecker::CheckExplicitInitList(InitListExpr *IList, QualType &T,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex) {
assert(IList->isExplicit() && "Illegal Implicit InitListExpr");
SyntacticToSemantic[IList] = StructuredList;
StructuredList->setSyntacticForm(IList);
CheckListElementTypes(IList, T, true, Index, StructuredList,
StructuredIndex);
IList->setType(T);
StructuredList->setType(T);
if (hadError)
return;
if (Index < IList->getNumInits()) {
// We have leftover initializers
if (IList->getNumInits() > 0 &&
SemaRef->IsStringLiteralInit(IList->getInit(Index), T)) {
// Special-case
SemaRef->Diag(IList->getInit(Index)->getLocStart(),
diag::err_excess_initializers_in_char_array_initializer)
<< IList->getInit(Index)->getSourceRange();
hadError = true;
} else if (!T->isIncompleteType()) {
// Don't warn for incomplete types, since we'll get an error elsewhere
SemaRef->Diag(IList->getInit(Index)->getLocStart(),
diag::warn_excess_initializers)
<< IList->getInit(Index)->getSourceRange();
}
}
if (T->isScalarType())
SemaRef->Diag(IList->getLocStart(), diag::warn_braces_around_scalar_init)
<< IList->getSourceRange();
}
void InitListChecker::CheckListElementTypes(InitListExpr *IList,
QualType &DeclType,
bool SubobjectIsDesignatorContext,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex) {
if (DeclType->isScalarType()) {
CheckScalarType(IList, DeclType, Index, StructuredList, StructuredIndex);
} else if (DeclType->isVectorType()) {
CheckVectorType(IList, DeclType, Index, StructuredList, StructuredIndex);
} else if (DeclType->isAggregateType()) {
if (DeclType->isRecordType()) {
RecordDecl *RD = DeclType->getAsRecordType()->getDecl();
CheckStructUnionTypes(IList, DeclType, RD->field_begin(),
SubobjectIsDesignatorContext, Index,
StructuredList, StructuredIndex);
} else if (DeclType->isArrayType()) {
llvm::APSInt Zero(
SemaRef->Context.getTypeSize(SemaRef->Context.getSizeType()),
false);
CheckArrayType(IList, DeclType, Zero, SubobjectIsDesignatorContext, Index,
StructuredList, StructuredIndex);
}
else
assert(0 && "Aggregate that isn't a structure or array?!");
} else if (DeclType->isVoidType() || DeclType->isFunctionType()) {
// This type is invalid, issue a diagnostic.
++Index;
SemaRef->Diag(IList->getLocStart(), diag::err_illegal_initializer_type)
<< DeclType;
hadError = true;
} else {
// In C, all types are either scalars or aggregates, but
// additional handling is needed here for C++ (and possibly others?).
assert(0 && "Unsupported initializer type");
}
}
void InitListChecker::CheckSubElementType(InitListExpr *IList,
QualType ElemType,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex) {
Expr *expr = IList->getInit(Index);
if (InitListExpr *SubInitList = dyn_cast<InitListExpr>(expr)) {
unsigned newIndex = 0;
unsigned newStructuredIndex = 0;
InitListExpr *newStructuredList
= getStructuredSubobjectInit(IList, Index, ElemType,
StructuredList, StructuredIndex,
SubInitList->getSourceRange());
CheckExplicitInitList(SubInitList, ElemType, newIndex,
newStructuredList, newStructuredIndex);
++StructuredIndex;
++Index;
} else if (StringLiteral *lit =
SemaRef->IsStringLiteralInit(expr, ElemType)) {
SemaRef->CheckStringLiteralInit(lit, ElemType);
UpdateStructuredListElement(StructuredList, StructuredIndex, lit);
++Index;
} else if (ElemType->isScalarType()) {
CheckScalarType(IList, ElemType, Index, StructuredList, StructuredIndex);
} else if (expr->getType()->getAsRecordType() &&
SemaRef->Context.typesAreCompatible(
expr->getType().getUnqualifiedType(),
ElemType.getUnqualifiedType())) {
UpdateStructuredListElement(StructuredList, StructuredIndex, expr);
++Index;
// FIXME: Add checking
} else {
CheckImplicitInitList(IList, ElemType, Index, StructuredList,
StructuredIndex);
++StructuredIndex;
}
}
void InitListChecker::CheckScalarType(InitListExpr *IList, QualType &DeclType,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex) {
if (Index < IList->getNumInits()) {
Expr *expr = IList->getInit(Index);
if (isa<InitListExpr>(expr)) {
SemaRef->Diag(IList->getLocStart(),
diag::err_many_braces_around_scalar_init)
<< IList->getSourceRange();
hadError = true;
++Index;
++StructuredIndex;
return;
} else if (isa<DesignatedInitExpr>(expr)) {
SemaRef->Diag(expr->getSourceRange().getBegin(),
diag::err_designator_for_scalar_init)
<< DeclType << expr->getSourceRange();
hadError = true;
++Index;
++StructuredIndex;
return;
}
Expr *savExpr = expr; // Might be promoted by CheckSingleInitializer.
if (SemaRef->CheckSingleInitializer(expr, DeclType, false))
hadError = true; // types weren't compatible.
else if (savExpr != expr) {
// The type was promoted, update initializer list.
IList->setInit(Index, expr);
}
if (hadError)
++StructuredIndex;
else
UpdateStructuredListElement(StructuredList, StructuredIndex, expr);
++Index;
} else {
SemaRef->Diag(IList->getLocStart(), diag::err_empty_scalar_initializer)
<< IList->getSourceRange();
hadError = true;
++Index;
++StructuredIndex;
return;
}
}
void InitListChecker::CheckVectorType(InitListExpr *IList, QualType DeclType,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex) {
if (Index < IList->getNumInits()) {
const VectorType *VT = DeclType->getAsVectorType();
int maxElements = VT->getNumElements();
QualType elementType = VT->getElementType();
for (int i = 0; i < maxElements; ++i) {
// Don't attempt to go past the end of the init list
if (Index >= IList->getNumInits())
break;
CheckSubElementType(IList, elementType, Index,
StructuredList, StructuredIndex);
}
}
}
void InitListChecker::CheckArrayType(InitListExpr *IList, QualType &DeclType,
llvm::APSInt elementIndex,
bool SubobjectIsDesignatorContext,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex) {
// Check for the special-case of initializing an array with a string.
if (Index < IList->getNumInits()) {
if (StringLiteral *lit =
SemaRef->IsStringLiteralInit(IList->getInit(Index), DeclType)) {
SemaRef->CheckStringLiteralInit(lit, DeclType);
// 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.
UpdateStructuredListElement(StructuredList, StructuredIndex, lit);
StructuredList->resizeInits(SemaRef->Context, StructuredIndex);
++Index;
return;
}
}
if (const VariableArrayType *VAT =
SemaRef->Context.getAsVariableArrayType(DeclType)) {
// 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).
SemaRef->Diag(VAT->getSizeExpr()->getLocStart(),
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 =
SemaRef->Context.getAsConstantArrayType(DeclType)) {
maxElements = CAT->getSize();
elementIndex.extOrTrunc(maxElements.getBitWidth());
elementIndex.setIsUnsigned(maxElements.isUnsigned());
maxElementsKnown = true;
}
QualType elementType = SemaRef->Context.getAsArrayType(DeclType)
->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(IList, DIE, DIE->designators_begin(),
DeclType, 0, &elementIndex, Index,
StructuredList, StructuredIndex)) {
hadError = true;
continue;
}
if (elementIndex.getBitWidth() > maxElements.getBitWidth())
maxElements.extend(elementIndex.getBitWidth());
else if (elementIndex.getBitWidth() < maxElements.getBitWidth())
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;
// Check this element.
CheckSubElementType(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 (DeclType->isIncompleteArrayType()) {
// 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) {
// Sizing an array implicitly to zero is not allowed by ISO C,
// but is supported by GNU.
SemaRef->Diag(IList->getLocStart(),
diag::ext_typecheck_zero_array_size);
}
DeclType = SemaRef->Context.getConstantArrayType(elementType, maxElements,
ArrayType::Normal, 0);
}
}
void InitListChecker::CheckStructUnionTypes(InitListExpr *IList,
QualType DeclType,
RecordDecl::field_iterator Field,
bool SubobjectIsDesignatorContext,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex) {
RecordDecl* structDecl = DeclType->getAsRecordType()->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()) {
hadError = true;
return;
}
if (DeclType->isUnionType() && IList->getNumInits() == 0) {
// Value-initialize the first named member of the union.
RecordDecl *RD = DeclType->getAsRecordType()->getDecl();
for (RecordDecl::field_iterator FieldEnd = RD->field_end();
Field != FieldEnd; ++Field) {
if (Field->getDeclName()) {
StructuredList->setInitializedFieldInUnion(*Field);
break;
}
}
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->getAsRecordType()->getDecl();
RecordDecl::field_iterator FieldEnd = RD->field_end();
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. Field will be updated to
// the next field that we'll be initializing.
if (CheckDesignatedInitializer(IList, DIE, DIE->designators_begin(),
DeclType, &Field, 0, Index,
StructuredList, StructuredIndex))
hadError = true;
// Abort early for unions: the designator handled the
// initialization of the appropriate field.
if (DeclType->isUnionType())
break;
continue;
}
if (Field == FieldEnd) {
// We've run out of fields. We're done.
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;
}
CheckSubElementType(IList, Field->getType(), Index,
StructuredList, StructuredIndex);
if (DeclType->isUnionType()) {
// Initialize the first field within the union.
StructuredList->setInitializedFieldInUnion(*Field);
break;
}
++Field;
}
// FIXME: Implement flexible array initialization GCC extension (it's a
// really messy extension to implement, unfortunately...the necessary
// information isn't actually even here!)
}
/// @brief 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 and its initialization
/// expression.
///
/// @param DeclType 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.
///
/// @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(InitListExpr *IList,
DesignatedInitExpr *DIE,
DesignatedInitExpr::designators_iterator D,
QualType &CurrentObjectType,
RecordDecl::field_iterator *NextField,
llvm::APSInt *NextElementIndex,
unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex,
bool FinishSubobjectInit) {
if (D == DIE->designators_end()) {
// 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(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;
}
bool IsFirstDesignator = (D == DIE->designators_begin());
assert((IsFirstDesignator || StructuredList) &&
"Need a non-designated initializer list to start from");
// Determine the structural initializer list that corresponds to the
// current subobject.
StructuredList = IsFirstDesignator? SyntacticToSemantic[IList]
: getStructuredSubobjectInit(IList, Index, CurrentObjectType, StructuredList,
StructuredIndex,
SourceRange(D->getStartLocation(),
DIE->getSourceRange().getEnd()));
assert(StructuredList && "Expected a structured initializer list");
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->getAsRecordType();
if (!RT) {
SourceLocation Loc = D->getDotLoc();
if (Loc.isInvalid())
Loc = D->getFieldLoc();
SemaRef->Diag(Loc, diag::err_field_designator_non_aggr)
<< SemaRef->getLangOptions().CPlusPlus << CurrentObjectType;
++Index;
return true;
}
// Note: we perform a linear search of the fields here, despite
// the fact that we have a faster lookup method, because we always
// need to compute the field's index.
IdentifierInfo *FieldName = D->getFieldName();
unsigned FieldIndex = 0;
RecordDecl::field_iterator Field = RT->getDecl()->field_begin(),
FieldEnd = RT->getDecl()->field_end();
for (; Field != FieldEnd; ++Field) {
if (Field->isUnnamedBitfield())
continue;
if (Field->getIdentifier() == FieldName)
break;
++FieldIndex;
}
if (Field == FieldEnd) {
// We did not find the field we're looking for. Produce a
// suitable diagnostic and return a failure.
DeclContext::lookup_result Lookup = RT->getDecl()->lookup(FieldName);
if (Lookup.first == Lookup.second) {
// Name lookup didn't find anything.
SemaRef->Diag(D->getFieldLoc(), diag::err_field_designator_unknown)
<< FieldName << CurrentObjectType;
} else {
// Name lookup found something, but it wasn't a field.
SemaRef->Diag(D->getFieldLoc(), diag::err_field_designator_nonfield)
<< FieldName;
SemaRef->Diag((*Lookup.first)->getLocation(),
diag::note_field_designator_found);
}
++Index;
return true;
} else if (cast<RecordDecl>((*Field)->getDeclContext())
->isAnonymousStructOrUnion()) {
SemaRef->Diag(D->getFieldLoc(), diag::err_field_designator_anon_class)
<< FieldName
<< (cast<RecordDecl>((*Field)->getDeclContext())->isUnion()? 2 :
(int)SemaRef->getLangOptions().CPlusPlus);
SemaRef->Diag((*Field)->getLocation(), diag::note_field_designator_found);
++Index;
return true;
}
// All of the fields of a union are located at the same place in
// the initializer list.
if (RT->getDecl()->isUnion()) {
FieldIndex = 0;
StructuredList->setInitializedFieldInUnion(*Field);
}
// Update the designator with the field declaration.
D->setField(*Field);
// Make sure that our non-designated initializer list has space
// for a subobject corresponding to this field.
if (FieldIndex >= StructuredList->getNumInits())
StructuredList->resizeInits(SemaRef->Context, FieldIndex + 1);
// Recurse to check later designated subobjects.
QualType FieldType = (*Field)->getType();
unsigned newStructuredIndex = FieldIndex;
if (CheckDesignatedInitializer(IList, DIE, ++D, FieldType, 0, 0, Index,
StructuredList, newStructuredIndex))
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;
// Check the remaining fields within this class/struct/union subobject.
bool prevHadError = hadError;
CheckStructUnionTypes(IList, CurrentObjectType, 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) {
SemaRef->Diag(D->getLBracketLoc(), diag::err_array_designator_non_array)
<< CurrentObjectType;
++Index;
return true;
}
Expr *IndexExpr = 0;
llvm::APSInt DesignatedStartIndex, DesignatedEndIndex;
if (D->isArrayDesignator()) {
IndexExpr = DIE->getArrayIndex(*D);
bool ConstExpr
= IndexExpr->isIntegerConstantExpr(DesignatedStartIndex, SemaRef->Context);
assert(ConstExpr && "Expression must be constant"); (void)ConstExpr;
DesignatedEndIndex = DesignatedStartIndex;
} else {
assert(D->isArrayRangeDesignator() && "Need array-range designator");
bool StartConstExpr
= DIE->getArrayRangeStart(*D)->isIntegerConstantExpr(DesignatedStartIndex,
SemaRef->Context);
assert(StartConstExpr && "Expression must be constant"); (void)StartConstExpr;
bool EndConstExpr
= DIE->getArrayRangeEnd(*D)->isIntegerConstantExpr(DesignatedEndIndex,
SemaRef->Context);
assert(EndConstExpr && "Expression must be constant"); (void)EndConstExpr;
IndexExpr = DIE->getArrayRangeEnd(*D);
if (DesignatedStartIndex.getZExtValue() != DesignatedEndIndex.getZExtValue())
FullyStructuredList->sawArrayRangeDesignator();
}
if (isa<ConstantArrayType>(AT)) {
llvm::APSInt MaxElements(cast<ConstantArrayType>(AT)->getSize(), false);
DesignatedStartIndex.extOrTrunc(MaxElements.getBitWidth());
DesignatedStartIndex.setIsUnsigned(MaxElements.isUnsigned());
DesignatedEndIndex.extOrTrunc(MaxElements.getBitWidth());
DesignatedEndIndex.setIsUnsigned(MaxElements.isUnsigned());
if (DesignatedEndIndex >= MaxElements) {
SemaRef->Diag(IndexExpr->getSourceRange().getBegin(),
diag::err_array_designator_too_large)
<< DesignatedEndIndex.toString(10) << MaxElements.toString(10)
<< IndexExpr->getSourceRange();
++Index;
return true;
}
} else {
// Make sure the bit-widths and signedness match.
if (DesignatedStartIndex.getBitWidth() > DesignatedEndIndex.getBitWidth())
DesignatedEndIndex.extend(DesignatedStartIndex.getBitWidth());
else if (DesignatedStartIndex.getBitWidth() < DesignatedEndIndex.getBitWidth())
DesignatedStartIndex.extend(DesignatedEndIndex.getBitWidth());
DesignatedStartIndex.setIsUnsigned(true);
DesignatedEndIndex.setIsUnsigned(true);
}
// Make sure that our non-designated initializer list has space
// for a subobject corresponding to this array element.
if (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;
++D;
while (DesignatedStartIndex <= DesignatedEndIndex) {
// Recurse to check later designated subobjects.
QualType ElementType = AT->getElementType();
Index = OldIndex;
if (CheckDesignatedInitializer(IList, DIE, D, ElementType, 0, 0, Index,
StructuredList, ElementIndex,
(DesignatedStartIndex == DesignatedEndIndex)))
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(IList, CurrentObjectType, DesignatedStartIndex, true, 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) {
Expr *ExistingInit = 0;
if (!StructuredList)
ExistingInit = SyntacticToSemantic[IList];
else if (StructuredIndex < StructuredList->getNumInits())
ExistingInit = StructuredList->getInit(StructuredIndex);
if (InitListExpr *Result = dyn_cast_or_null<InitListExpr>(ExistingInit))
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, 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 == 0 and xs[0].b == 3, since the second,
// designated initializer re-initializes the whole
// subobject [0], overwriting previous initializers.
SemaRef->Diag(InitRange.getBegin(), diag::warn_subobject_initializer_overrides)
<< InitRange;
SemaRef->Diag(ExistingInit->getSourceRange().getBegin(),
diag::note_previous_initializer)
<< /*FIXME:has side effects=*/0
<< ExistingInit->getSourceRange();
}
InitListExpr *Result
= new (SemaRef->Context) InitListExpr(SourceLocation(), 0, 0,
SourceLocation());
Result->setType(CurrentObjectType);
// Link this new initializer list into the structured initializer
// lists.
if (StructuredList)
StructuredList->updateInit(StructuredIndex, Result);
else {
Result->setSyntacticForm(IList);
SyntacticToSemantic[IList] = Result;
}
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(StructuredIndex, expr)) {
// This initializer overwrites a previous initializer. Warn.
SemaRef->Diag(expr->getSourceRange().getBegin(),
diag::warn_initializer_overrides)
<< expr->getSourceRange();
SemaRef->Diag(PrevInit->getSourceRange().getBegin(),
diag::note_previous_initializer)
<< /*FIXME:has side effects=*/0
<< PrevInit->getSourceRange();
}
++StructuredIndex;
}
/// Check that the given Index expression is a valid array designator
/// value. This is essentailly just a wrapper around
/// Expr::isIntegerConstantExpr that also checks for negative values
/// and produces a reasonable diagnostic if there is a
/// failure. Returns true if there was an error, false otherwise. If
/// everything went okay, Value will receive the value of the constant
/// expression.
static bool
CheckArrayDesignatorExpr(Sema &Self, Expr *Index, llvm::APSInt &Value) {
SourceLocation Loc = Index->getSourceRange().getBegin();
// Make sure this is an integer constant expression.
if (!Index->isIntegerConstantExpr(Value, Self.Context, &Loc))
return Self.Diag(Loc, diag::err_array_designator_nonconstant)
<< Index->getSourceRange();
// Make sure this constant expression is non-negative.
llvm::APSInt Zero(llvm::APSInt::getNullValue(Value.getBitWidth()),
Value.isUnsigned());
if (Value < Zero)
return Self.Diag(Loc, diag::err_array_designator_negative)
<< Value.toString(10) << Index->getSourceRange();
Value.setIsUnsigned(true);
return false;
}
Sema::OwningExprResult Sema::ActOnDesignatedInitializer(Designation &Desig,
SourceLocation Loc,
bool UsedColonSyntax,
OwningExprResult Init) {
typedef DesignatedInitExpr::Designator ASTDesignator;
bool Invalid = false;
llvm::SmallVector<ASTDesignator, 32> Designators;
llvm::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 (CheckArrayDesignatorExpr(*this, Index, IndexValue))
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;
if (CheckArrayDesignatorExpr(*this, StartIndex, StartValue) ||
CheckArrayDesignatorExpr(*this, EndIndex, EndValue))
Invalid = true;
else {
// Make sure we're comparing values with the same bit width.
if (StartValue.getBitWidth() > EndValue.getBitWidth())
EndValue.extend(StartValue.getBitWidth());
else if (StartValue.getBitWidth() < EndValue.getBitWidth())
StartValue.extend(EndValue.getBitWidth());
if (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);
DesignatedInitExpr *DIE
= DesignatedInitExpr::Create(Context, &Designators[0], Designators.size(),
&InitExpressions[0], InitExpressions.size(),
Loc, UsedColonSyntax,
static_cast<Expr *>(Init.release()));
return Owned(DIE);
}
bool Sema::CheckInitList(InitListExpr *&InitList, QualType &DeclType) {
InitListChecker CheckInitList(this, InitList, DeclType);
if (!CheckInitList.HadError())
InitList = CheckInitList.getFullyStructuredList();
return CheckInitList.HadError();
}
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