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Don't mark 'extern "C" void f(void)' as having extern storage class. 

Instead, we check for one line extern "C" context in linkage computation and
when deciding if a variable is a definition.

This hopefully completes the transition to having "as written" semantics for
hasExternalStorage.

llvm-svn: 180258
This commit is contained in:
Rafael Espindola 2013-04-25 12:11:36 +00:00
parent 5c38383205
commit bff5956cfa
3 changed files with 33 additions and 17 deletions
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17
clang/lib/AST/Decl.cpp
View File

@ -1572,17 +1572,20 @@ VarDecl::DefinitionKind VarDecl::isThisDeclarationADefinition(
// initializer, the declaration is an external definition for the identifier
if (hasInit())
return Definition;
// AST for 'extern "C" int foo;' is annotated with 'extern'.
if (hasExternalStorage())
return DeclarationOnly;
if (hasExternalStorage()) {
for (const VarDecl *PrevVar = getPreviousDecl();
PrevVar; PrevVar = PrevVar->getPreviousDecl()) {
if (PrevVar->getLinkage() == InternalLinkage)
return DeclarationOnly;
}
// [dcl.link] p7:
// A declaration directly contained in a linkage-specification is treated
// as if it contains the extern specifier for the purpose of determining
// the linkage of the declared name and whether it is a definition.
const DeclContext *DC = getDeclContext();
if (const LinkageSpecDecl *SD = dyn_cast<LinkageSpecDecl>(DC)) {
if (SD->getLanguage() == LinkageSpecDecl::lang_c && !SD->hasBraces())
return DeclarationOnly;
}
// C99 6.9.2p2:
// A declaration of an object that has file scope without an initializer,
// and without a storage class specifier or the scs 'static', constitutes

26
clang/lib/Sema/SemaDecl.cpp
View File

@ -3350,10 +3350,16 @@ static bool InjectAnonymousStructOrUnionMembers(Sema &SemaRef, Scope *S,
/// a VarDecl::StorageClass. Any error reporting is up to the caller:
/// illegal input values are mapped to SC_None.
static StorageClass
StorageClassSpecToVarDeclStorageClass(DeclSpec::SCS StorageClassSpec) {
StorageClassSpecToVarDeclStorageClass(const DeclSpec &DS) {
DeclSpec::SCS StorageClassSpec = DS.getStorageClassSpec();
assert(StorageClassSpec != DeclSpec::SCS_typedef &&
"Parser allowed 'typedef' as storage class VarDecl.");
switch (StorageClassSpec) {
case DeclSpec::SCS_unspecified: return SC_None;
case DeclSpec::SCS_extern: return SC_Extern;
case DeclSpec::SCS_extern:
if (DS.isExternInLinkageSpec())
return SC_None;
return SC_Extern;
case DeclSpec::SCS_static: return SC_Static;
case DeclSpec::SCS_auto: return SC_Auto;
case DeclSpec::SCS_register: return SC_Register;
@ -3551,9 +3557,7 @@ Decl *Sema::BuildAnonymousStructOrUnion(Scope *S, DeclSpec &DS,
FieldCollector->Add(cast<FieldDecl>(Anon));
} else {
DeclSpec::SCS SCSpec = DS.getStorageClassSpec();
assert(SCSpec != DeclSpec::SCS_typedef &&
"Parser allowed 'typedef' as storage class VarDecl.");
VarDecl::StorageClass SC = StorageClassSpecToVarDeclStorageClass(SCSpec);
VarDecl::StorageClass SC = StorageClassSpecToVarDeclStorageClass(DS);
if (SCSpec == DeclSpec::SCS_mutable) {
// mutable can only appear on non-static class members, so it's always
// an error here
@ -4676,9 +4680,8 @@ Sema::ActOnVariableDeclarator(Scope *S, Declarator &D, DeclContext *DC,
DeclarationName Name = GetNameForDeclarator(D).getName();
DeclSpec::SCS SCSpec = D.getDeclSpec().getStorageClassSpec();
assert(SCSpec != DeclSpec::SCS_typedef &&
"Parser allowed 'typedef' as storage class VarDecl.");
VarDecl::StorageClass SC = StorageClassSpecToVarDeclStorageClass(SCSpec);
VarDecl::StorageClass SC =
StorageClassSpecToVarDeclStorageClass(D.getDeclSpec());
if (getLangOpts().OpenCL && !getOpenCLOptions().cl_khr_fp16) {
// OpenCL v1.2 s6.1.1.1: reject declaring variables of the half and
@ -5290,7 +5293,7 @@ bool Sema::CheckVariableDeclaration(VarDecl *NewVD,
// Filter out any non-conflicting previous declarations.
filterNonConflictingPreviousDecls(Context, NewVD, Previous);
if (T->isVoidType() && !NewVD->hasExternalStorage()) {
if (T->isVoidType() && NewVD->isThisDeclarationADefinition()) {
Diag(NewVD->getLocation(), diag::err_typecheck_decl_incomplete_type)
<< T;
NewVD->setInvalidDecl();
@ -5642,7 +5645,10 @@ static FunctionDecl::StorageClass getFunctionStorageClass(Sema &SemaRef,
D.setInvalidType();
break;
case DeclSpec::SCS_unspecified: break;
case DeclSpec::SCS_extern: return SC_Extern;
case DeclSpec::SCS_extern:
if (D.getDeclSpec().isExternInLinkageSpec())
return SC_None;
return SC_Extern;
case DeclSpec::SCS_static: {
if (SemaRef.CurContext->getRedeclContext()->isFunctionOrMethod()) {
// C99 6.7.1p5:

7
clang/test/CXX/dcl.dcl/dcl.link/p7-2.cpp Normal file
View File

@ -0,0 +1,7 @@
// RUN: %clang_cc1 -ast-print -o - %s | FileCheck %s
extern "C" void f(void);
// CHECK: extern "C" void f()
extern "C" void v;
// CHECK: extern "C" void v