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Explictly track tentative definitions within Sema, then hand those

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tentative definitions off to the ASTConsumer at the end of the
translation unit. 

Eliminate CodeGen's internal tracking of tentative definitions, and
instead hook into ASTConsumer::CompleteTentativeDefinition. Also,
tweak the definition-deferal logic for C++, where there are no
tentative definitions.

Fixes <rdar://problem/6808352>, and will make it much easier for
precompiled headers to cope with tentative definitions in the future.

llvm-svn: 69681
This commit is contained in:
Douglas Gregor
2009-04-21 17:11:58 +00:00
parent 69223bb7f5
commit beecd58e21
12 changed files with 103 additions and 63 deletions
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27
clang/lib/CodeGen/CodeGenModule.cpp
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@@ -424,13 +424,6 @@ void CodeGenModule::EmitDeferred() {
// Otherwise, emit the definition and move on to the next one.
EmitGlobalDefinition(D);
}
// Emit any tentative definitions, in reverse order so the most
// important (merged) decl will be seen and emitted first.
for (std::vector<const VarDecl*>::reverse_iterator
it = TentativeDefinitions.rbegin(), ie = TentativeDefinitions.rend();
it != ie; ++it)
EmitTentativeDefinition(*it);
}
/// EmitAnnotateAttr - Generate the llvm::ConstantStruct which contains the
@@ -502,6 +495,7 @@ bool CodeGenModule::MayDeferGeneration(const ValueDecl *Global) {
const VarDecl *VD = cast<VarDecl>(Global);
assert(VD->isFileVarDecl() && "Invalid decl");
return VD->getStorageClass() == VarDecl::Static;
}
@@ -520,16 +514,14 @@ void CodeGenModule::EmitGlobal(const ValueDecl *Global) {
const VarDecl *VD = cast<VarDecl>(Global);
assert(VD->isFileVarDecl() && "Cannot emit local var decl as global.");
// If this isn't a definition, defer code generation.
if (!VD->getInit()) {
// If this is a tentative definition, remember it so that we can
// emit the common definition if needed. It is important to
// defer tentative definitions, since they may have incomplete
// type.
if (!VD->hasExternalStorage())
TentativeDefinitions.push_back(VD);
// In C++, if this is marked "extern", defer code generation.
if (getLangOptions().CPlusPlus &&
VD->getStorageClass() == VarDecl::Extern && !VD->getInit())
return;
// In C, if this isn't a definition, defer code generation.
if (!getLangOptions().CPlusPlus && !VD->getInit())
return;
}
}
// Defer code generation when possible if this is a static definition, inline
@@ -727,6 +719,9 @@ void CodeGenModule::EmitTentativeDefinition(const VarDecl *D) {
// See if we have already defined this (as a variable), if so we do
// not need to do anything.
llvm::GlobalValue *GV = GlobalDeclMap[getMangledName(D)];
if (!GV && MayDeferGeneration(D)) // this variable was never referenced
return;
if (llvm::GlobalVariable *Var = dyn_cast_or_null<llvm::GlobalVariable>(GV))
if (Var->hasInitializer())
return;