[modules] If we reach a definition of a class for which we already have a

non-visible definition, skip the new definition and make the old one visible
instead of trying to parse it again and failing horribly. C++'s ODR allows
us to assume that the two definitions are identical.

llvm-svn: 233250
This commit is contained in:
Richard Smith 2015-03-26 04:09:53 +00:00
parent e972c36221
commit 65ebb4ac8a
18 changed files with 182 additions and 14 deletions

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@ -24,6 +24,7 @@ namespace clang {
class DeclContext;
class FunctionDecl;
class FunctionTemplateDecl;
class NamedDecl;
class ObjCCategoryDecl;
class ObjCContainerDecl;
class ObjCInterfaceDecl;
@ -113,6 +114,12 @@ public:
/// \param D the declaration marked OpenMP threadprivate.
virtual void DeclarationMarkedOpenMPThreadPrivate(const Decl *D) {}
/// \brief A definition has been made visible by being redefined locally.
///
/// \param D The definition that was previously not visible.
virtual void RedefinedHiddenDefinition(const NamedDecl *D,
SourceLocation Loc) {}
// NOTE: If new methods are added they should also be added to
// MultiplexASTMutationListener.
};

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@ -2284,6 +2284,10 @@ private:
AccessSpecifier AS, bool EnteringContext,
DeclSpecContext DSC,
ParsedAttributesWithRange &Attributes);
void SkipCXXMemberSpecification(SourceLocation StartLoc,
SourceLocation AttrFixitLoc,
unsigned TagType,
Decl *TagDecl);
void ParseCXXMemberSpecification(SourceLocation StartLoc,
SourceLocation AttrFixitLoc,
ParsedAttributesWithRange &Attrs,

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@ -1279,6 +1279,10 @@ private:
bool RequireCompleteTypeImpl(SourceLocation Loc, QualType T,
TypeDiagnoser &Diagnoser);
public:
/// Determine if \p D has a visible definition. If not, suggest a declaration
/// that should be made visible to expose the definition.
bool hasVisibleDefinition(NamedDecl *D, NamedDecl **Suggested);
bool RequireCompleteType(SourceLocation Loc, QualType T,
TypeDiagnoser &Diagnoser);
bool RequireCompleteType(SourceLocation Loc, QualType T,
@ -1725,7 +1729,7 @@ public:
bool &OwnedDecl, bool &IsDependent,
SourceLocation ScopedEnumKWLoc,
bool ScopedEnumUsesClassTag, TypeResult UnderlyingType,
bool IsTypeSpecifier);
bool IsTypeSpecifier, bool *SkipBody = nullptr);
Decl *ActOnTemplatedFriendTag(Scope *S, SourceLocation FriendLoc,
unsigned TagSpec, SourceLocation TagLoc,
@ -1790,6 +1794,11 @@ public:
/// struct, or union).
void ActOnTagStartDefinition(Scope *S, Decl *TagDecl);
/// \brief Invoked when we enter a tag definition that we're skipping.
void ActOnTagStartSkippedDefinition(Scope *S, Decl *TD) {
PushDeclContext(S, cast<DeclContext>(TD));
}
Decl *ActOnObjCContainerStartDefinition(Decl *IDecl);
/// ActOnStartCXXMemberDeclarations - Invoked when we have parsed a
@ -1805,6 +1814,10 @@ public:
void ActOnTagFinishDefinition(Scope *S, Decl *TagDecl,
SourceLocation RBraceLoc);
void ActOnTagFinishSkippedDefinition() {
PopDeclContext();
}
void ActOnObjCContainerFinishDefinition();
/// \brief Invoked when we must temporarily exit the objective-c container

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@ -861,6 +861,8 @@ public:
const ObjCCategoryDecl *ClassExt) override;
void DeclarationMarkedUsed(const Decl *D) override;
void DeclarationMarkedOpenMPThreadPrivate(const Decl *D) override;
void RedefinedHiddenDefinition(const NamedDecl *D,
SourceLocation Loc) override;
};
/// \brief AST and semantic-analysis consumer that generates a

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@ -110,6 +110,8 @@ public:
const ObjCCategoryDecl *ClassExt) override;
void DeclarationMarkedUsed(const Decl *D) override;
void DeclarationMarkedOpenMPThreadPrivate(const Decl *D) override;
void RedefinedHiddenDefinition(const NamedDecl *D,
SourceLocation Loc) override;
private:
std::vector<ASTMutationListener*> Listeners;
@ -193,6 +195,11 @@ void MultiplexASTMutationListener::DeclarationMarkedOpenMPThreadPrivate(
for (size_t i = 0, e = Listeners.size(); i != e; ++i)
Listeners[i]->DeclarationMarkedOpenMPThreadPrivate(D);
}
void MultiplexASTMutationListener::RedefinedHiddenDefinition(
const NamedDecl *D, SourceLocation Loc) {
for (auto *L : Listeners)
L->RedefinedHiddenDefinition(D, Loc);
}
} // end namespace clang

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@ -1550,6 +1550,7 @@ void Parser::ParseClassSpecifier(tok::TokenKind TagTokKind,
TypeResult TypeResult = true; // invalid
bool Owned = false;
bool SkipBody = false;
if (TemplateId) {
// Explicit specialization, class template partial specialization,
// or explicit instantiation.
@ -1695,7 +1696,8 @@ void Parser::ParseClassSpecifier(tok::TokenKind TagTokKind,
TParams, Owned, IsDependent,
SourceLocation(), false,
clang::TypeResult(),
DSC == DSC_type_specifier);
DSC == DSC_type_specifier,
&SkipBody);
// If ActOnTag said the type was dependent, try again with the
// less common call.
@ -1711,7 +1713,10 @@ void Parser::ParseClassSpecifier(tok::TokenKind TagTokKind,
assert(Tok.is(tok::l_brace) ||
(getLangOpts().CPlusPlus && Tok.is(tok::colon)) ||
isCXX11FinalKeyword());
if (getLangOpts().CPlusPlus)
if (SkipBody)
SkipCXXMemberSpecification(StartLoc, AttrFixitLoc, TagType,
TagOrTempResult.get());
else if (getLangOpts().CPlusPlus)
ParseCXXMemberSpecification(StartLoc, AttrFixitLoc, attrs, TagType,
TagOrTempResult.get());
else
@ -2688,6 +2693,55 @@ ExprResult Parser::ParseCXXMemberInitializer(Decl *D, bool IsFunction,
return ParseInitializer();
}
void Parser::SkipCXXMemberSpecification(SourceLocation RecordLoc,
SourceLocation AttrFixitLoc,
unsigned TagType, Decl *TagDecl) {
// Skip the optional 'final' keyword.
if (getLangOpts().CPlusPlus && Tok.is(tok::identifier)) {
assert(isCXX11FinalKeyword() && "not a class definition");
ConsumeToken();
// Diagnose any C++11 attributes after 'final' keyword.
// We deliberately discard these attributes.
ParsedAttributesWithRange Attrs(AttrFactory);
CheckMisplacedCXX11Attribute(Attrs, AttrFixitLoc);
// This can only happen if we had malformed misplaced attributes;
// we only get called if there is a colon or left-brace after the
// attributes.
if (Tok.isNot(tok::colon) && Tok.isNot(tok::l_brace))
return;
}
// Skip the base clauses. This requires actually parsing them, because
// otherwise we can't be sure where they end (a left brace may appear
// within a template argument).
if (Tok.is(tok::colon)) {
// Enter the scope of the class so that we can correctly parse its bases.
ParseScope ClassScope(this, Scope::ClassScope|Scope::DeclScope);
ParsingClassDefinition ParsingDef(*this, TagDecl, /*NonNestedClass*/ true,
TagType == DeclSpec::TST_interface);
Actions.ActOnTagStartSkippedDefinition(getCurScope(), TagDecl);
// Parse the bases but don't attach them to the class.
ParseBaseClause(nullptr);
Actions.ActOnTagFinishSkippedDefinition();
if (!Tok.is(tok::l_brace)) {
Diag(PP.getLocForEndOfToken(PrevTokLocation),
diag::err_expected_lbrace_after_base_specifiers);
return;
}
}
// Skip the body.
assert(Tok.is(tok::l_brace));
BalancedDelimiterTracker T(*this, tok::l_brace);
T.consumeOpen();
T.skipToEnd();
}
/// ParseCXXMemberSpecification - Parse the class definition.
///
/// member-specification:

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@ -218,6 +218,7 @@ bool Sema::RequireCompleteDeclContext(CXXScopeSpec &SS,
// Fixed enum types are complete, but they aren't valid as scopes
// until we see a definition, so awkwardly pull out this special
// case.
// FIXME: The definition might not be visible; complain if it is not.
const EnumType *enumType = dyn_cast_or_null<EnumType>(tagType);
if (!enumType || enumType->getDecl()->isCompleteDefinition())
return false;

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@ -16,6 +16,7 @@
#include "clang/AST/ASTConsumer.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/ASTLambda.h"
#include "clang/AST/ASTMutationListener.h"
#include "clang/AST/CXXInheritance.h"
#include "clang/AST/CharUnits.h"
#include "clang/AST/CommentDiagnostic.h"
@ -11233,13 +11234,16 @@ static FixItHint createFriendTagNNSFixIt(Sema &SemaRef, NamedDecl *ND, Scope *S,
return FixItHint::CreateInsertion(NameLoc, Insertion);
}
/// ActOnTag - This is invoked when we see 'struct foo' or 'struct {'. In the
/// \brief This is invoked when we see 'struct foo' or 'struct {'. In the
/// former case, Name will be non-null. In the later case, Name will be null.
/// TagSpec indicates what kind of tag this is. TUK indicates whether this is a
/// reference/declaration/definition of a tag.
///
/// IsTypeSpecifier is true if this is a type-specifier (or
/// \param IsTypeSpecifier \c true if this is a type-specifier (or
/// trailing-type-specifier) other than one in an alias-declaration.
///
/// \param SkipBody If non-null, will be set to true if the caller should skip
/// the definition of this tag, and treat it as if it were a declaration.
Decl *Sema::ActOnTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
SourceLocation KWLoc, CXXScopeSpec &SS,
IdentifierInfo *Name, SourceLocation NameLoc,
@ -11250,7 +11254,7 @@ Decl *Sema::ActOnTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
SourceLocation ScopedEnumKWLoc,
bool ScopedEnumUsesClassTag,
TypeResult UnderlyingType,
bool IsTypeSpecifier) {
bool IsTypeSpecifier, bool *SkipBody) {
// If this is not a definition, it must have a name.
IdentifierInfo *OrigName = Name;
assert((Name != nullptr || TUK == TUK_Definition) &&
@ -11676,7 +11680,7 @@ Decl *Sema::ActOnTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
// Diagnose attempts to redefine a tag.
if (TUK == TUK_Definition) {
if (TagDecl *Def = PrevTagDecl->getDefinition()) {
if (NamedDecl *Def = PrevTagDecl->getDefinition()) {
// If we're defining a specialization and the previous definition
// is from an implicit instantiation, don't emit an error
// here; we'll catch this in the general case below.
@ -11692,7 +11696,19 @@ Decl *Sema::ActOnTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
TSK_ExplicitSpecialization;
}
if (!IsExplicitSpecializationAfterInstantiation) {
if (SkipBody && getLangOpts().CPlusPlus &&
!hasVisibleDefinition(Def, &Def)) {
// There is a definition of this tag, but it is not visible. We
// explicitly make use of C++'s one definition rule here, and
// assume that this definition is identical to the hidden one
// we already have. Make the existing definition visible and
// use it in place of this one.
*SkipBody = true;
if (auto *Listener = getASTMutationListener())
Listener->RedefinedHiddenDefinition(Def, KWLoc);
Def->setHidden(false);
return Def;
} else if (!IsExplicitSpecializationAfterInstantiation) {
// A redeclaration in function prototype scope in C isn't
// visible elsewhere, so merely issue a warning.
if (!getLangOpts().CPlusPlus && S->containedInPrototypeScope())

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@ -5126,9 +5126,9 @@ bool Sema::RequireCompleteType(SourceLocation Loc, QualType T,
/// \param D The definition of the entity.
/// \param Suggested Filled in with the declaration that should be made visible
/// in order to provide a definition of this entity.
static bool hasVisibleDefinition(Sema &S, NamedDecl *D, NamedDecl **Suggested) {
bool Sema::hasVisibleDefinition(NamedDecl *D, NamedDecl **Suggested) {
// Easy case: if we don't have modules, all declarations are visible.
if (!S.getLangOpts().Modules)
if (!getLangOpts().Modules)
return true;
// If this definition was instantiated from a template, map back to the
@ -5144,7 +5144,7 @@ static bool hasVisibleDefinition(Sema &S, NamedDecl *D, NamedDecl **Suggested) {
// If the enum has a fixed underlying type, any declaration of it will do.
*Suggested = nullptr;
for (auto *Redecl : ED->redecls()) {
if (LookupResult::isVisible(S, Redecl))
if (LookupResult::isVisible(*this, Redecl))
return true;
if (Redecl->isThisDeclarationADefinition() ||
(Redecl->isCanonicalDecl() && !*Suggested))
@ -5159,7 +5159,7 @@ static bool hasVisibleDefinition(Sema &S, NamedDecl *D, NamedDecl **Suggested) {
// FIXME: If we merged any other decl into D, and that declaration is visible,
// then we should consider a definition to be visible.
*Suggested = D;
return LookupResult::isVisible(S, D);
return LookupResult::isVisible(*this, D);
}
/// Locks in the inheritance model for the given class and all of its bases.
@ -5210,7 +5210,7 @@ bool Sema::RequireCompleteTypeImpl(SourceLocation Loc, QualType T,
// If we know about the definition but it is not visible, complain.
NamedDecl *SuggestedDef = nullptr;
if (!Diagnoser.Suppressed && Def &&
!hasVisibleDefinition(*this, Def, &SuggestedDef)) {
!hasVisibleDefinition(Def, &SuggestedDef)) {
// Suppress this error outside of a SFINAE context if we've already
// emitted the error once for this type. There's no usefulness in
// repeating the diagnostic.

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@ -35,7 +35,8 @@ enum DeclUpdateKind {
UPD_DECL_MARKED_USED,
UPD_MANGLING_NUMBER,
UPD_STATIC_LOCAL_NUMBER,
UPD_DECL_MARKED_OPENMP_THREADPRIVATE
UPD_DECL_MARKED_OPENMP_THREADPRIVATE,
UPD_DECL_EXPORTED
};
TypeIdx TypeIdxFromBuiltin(const BuiltinType *BT);

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@ -3793,10 +3793,24 @@ void ASTDeclReader::UpdateDecl(Decl *D, ModuleFile &ModuleFile,
case UPD_STATIC_LOCAL_NUMBER:
Reader.Context.setStaticLocalNumber(cast<VarDecl>(D), Record[Idx++]);
break;
case UPD_DECL_MARKED_OPENMP_THREADPRIVATE:
D->addAttr(OMPThreadPrivateDeclAttr::CreateImplicit(
Reader.Context, ReadSourceRange(Record, Idx)));
break;
case UPD_DECL_EXPORTED:
unsigned SubmoduleID = readSubmoduleID(Record, Idx);
Module *Owner = SubmoduleID ? Reader.getSubmodule(SubmoduleID) : nullptr;
if (Owner && Owner->NameVisibility != Module::AllVisible) {
// If Owner is made visible at some later point, make this declaration
// visible too.
Reader.HiddenNamesMap[Owner].HiddenDecls.push_back(D);
} else {
// The declaration is now visible.
D->Hidden = false;
}
break;
}
}
}

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@ -4927,10 +4927,15 @@ void ASTWriter::WriteDeclUpdatesBlocks(RecordDataImpl &OffsetsRecord) {
case UPD_STATIC_LOCAL_NUMBER:
Record.push_back(Update.getNumber());
break;
case UPD_DECL_MARKED_OPENMP_THREADPRIVATE:
AddSourceRange(D->getAttr<OMPThreadPrivateDeclAttr>()->getRange(),
Record);
break;
case UPD_DECL_EXPORTED:
Record.push_back(inferSubmoduleIDFromLocation(Update.getLoc()));
break;
}
}
@ -6074,3 +6079,11 @@ void ASTWriter::DeclarationMarkedOpenMPThreadPrivate(const Decl *D) {
DeclUpdates[D].push_back(DeclUpdate(UPD_DECL_MARKED_OPENMP_THREADPRIVATE));
}
void ASTWriter::RedefinedHiddenDefinition(const NamedDecl *D,
SourceLocation Loc) {
assert(!WritingAST && "Already writing the AST!");
assert(D->isHidden() && "expected a hidden declaration");
assert(D->isFromASTFile() && "hidden decl not from AST file");
DeclUpdates[D].push_back(DeclUpdate(UPD_DECL_EXPORTED, Loc));
}

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@ -0,0 +1,6 @@
struct A {};
class B {
struct Inner1 {};
struct Inner2;
};
struct B::Inner2 : Inner1 {};

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@ -0,0 +1,5 @@
// Trigger import of definitions, but don't make them visible.
#include "empty.h"
// Now parse the definitions again.
#include "defs.h"

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@ -0,0 +1,11 @@
module "stuff" {
textual header "defs.h"
module "empty" { header "empty.h" }
module "use" { header "use-defs.h" }
}
module "redef" {
header "import-and-redefine.h"
// Do not re-export stuff.use
use "stuff"
}

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@ -0,0 +1 @@
#include "defs.h"

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@ -0,0 +1,13 @@
// RUN: rm -rf %t
// RUN: %clang_cc1 -x c++ -fmodules-cache-path=%t -fmodules -I %S/Inputs/submodules-merge-defs %s -verify -fno-modules-error-recovery
// Trigger import of definitions, but don't make them visible.
#include "empty.h"
A pre_a; // expected-error {{must be imported}} expected-error {{must use 'struct'}}
// expected-note@defs.h:1 {{here}}
// Make definitions from second module visible.
#include "import-and-redefine.h"
A post_a;