Explictly track tentative definitions within Sema, then hand those
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.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@69681 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index 0526e78..9ae9359 100644
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -424,13 +424,6 @@
// 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 @@
const VarDecl *VD = cast<VarDecl>(Global);
assert(VD->isFileVarDecl() && "Invalid decl");
+
return VD->getStorageClass() == VarDecl::Static;
}
@@ -520,16 +514,14 @@
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 @@
// 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;
diff --git a/lib/CodeGen/CodeGenModule.h b/lib/CodeGen/CodeGenModule.h
index e7924fa..21ef8da 100644
--- a/lib/CodeGen/CodeGenModule.h
+++ b/lib/CodeGen/CodeGenModule.h
@@ -119,14 +119,6 @@
/// is done.
std::vector<const ValueDecl*> DeferredDeclsToEmit;
- /// TentativeDefinitions - A list of declarations which are
- /// tentative definitions. Code generation for these must be
- /// deferred because they are allowed to have incomplete type when
- /// they are seen. This also allows us to avoid generating an extra
- /// common definiton in situations where the tentative definition is
- /// followed by an actual definition.
- std::vector<const VarDecl*> TentativeDefinitions;
-
/// LLVMUsed - List of global values which are required to be
/// present in the object file; bitcast to i8*. This is used for
/// forcing visibility of symbols which may otherwise be optimized
@@ -339,6 +331,8 @@
CXXCtorType Type);
const char *getMangledCXXDtorName(const CXXDestructorDecl *D,
CXXDtorType Type);
+
+ void EmitTentativeDefinition(const VarDecl *D);
enum GVALinkage {
GVA_Internal,
@@ -382,7 +376,6 @@
void EmitGlobalDefinition(const ValueDecl *D);
void EmitGlobalFunctionDefinition(const FunctionDecl *D);
- void EmitTentativeDefinition(const VarDecl *D);
void EmitGlobalVarDefinition(const VarDecl *D);
void EmitAliasDefinition(const ValueDecl *D);
void EmitObjCPropertyImplementations(const ObjCImplementationDecl *D);
diff --git a/lib/CodeGen/ModuleBuilder.cpp b/lib/CodeGen/ModuleBuilder.cpp
index 896464e..9b85df6 100644
--- a/lib/CodeGen/ModuleBuilder.cpp
+++ b/lib/CodeGen/ModuleBuilder.cpp
@@ -83,6 +83,13 @@
if (Builder)
Builder->Release();
};
+
+ virtual void CompleteTentativeDefinition(VarDecl *D) {
+ if (Diags.hasErrorOccurred())
+ return;
+
+ Builder->EmitTentativeDefinition(D);
+ }
};
}