Don't use a global_ctors comdat for globals that aren't externally visible

In particular, if you have two identical templates in different TUs in
anonymous namespaces, we would use the same global_ctors comdat key for
both. As a result, only one would be run.

llvm-svn: 219806

1 files changed, 9 insertions, 9 deletions

diff --git a/clang/lib/CodeGen/CGDeclCXX.cpp b/clang/lib/CodeGen/CGDeclCXX.cpp
index ee3172ebc54..dcfc45ff84f 100644
--- a/clang/lib/CodeGen/CGDeclCXX.cpp
+++ b/clang/lib/CodeGen/CGDeclCXX.cpp
@@ -292,7 +292,8 @@ CodeGenModule::EmitCXXGlobalVarDeclInitFunc(const VarDecl *D,
   CodeGenFunction(*this).GenerateCXXGlobalVarDeclInitFunc(Fn, D, Addr,
                                                           PerformInit);
 
-  llvm::GlobalVariable *Key = supportsCOMDAT() ? Addr : nullptr;
+  llvm::GlobalVariable *COMDATKey =
+      supportsCOMDAT() && D->isExternallyVisible() ? Addr : nullptr;
 
   if (D->getTLSKind()) {
     // FIXME: Should we support init_priority for thread_local?
@@ -310,8 +311,7 @@ CodeGenModule::EmitCXXGlobalVarDeclInitFunc(const VarDecl *D,
     OrderGlobalInits Key(IPA->getPriority(), PrioritizedCXXGlobalInits.size());
     PrioritizedCXXGlobalInits.push_back(std::make_pair(Key, Fn));
     DelayedCXXInitPosition.erase(D);
-  } else if (D->getTemplateSpecializationKind() != TSK_ExplicitSpecialization &&
-             D->getTemplateSpecializationKind() != TSK_Undeclared) {
+  } else if (isTemplateInstantiation(D->getTemplateSpecializationKind())) {
     // C++ [basic.start.init]p2:
     //   Definitions of explicitly specialized class template static data
     //   members have ordered initialization. Other class template static data
@@ -320,16 +320,16 @@ CodeGenModule::EmitCXXGlobalVarDeclInitFunc(const VarDecl *D,
     //
     // As a consequence, we can put them into their own llvm.global_ctors entry.
     //
-    // In addition, put the initializer into a COMDAT group with the global
-    // being initialized.  On most platforms, this is a minor startup time
-    // optimization.  In the MS C++ ABI, there are no guard variables, so this
-    // COMDAT key is required for correctness.
-    AddGlobalCtor(Fn, 65535, Key);
+    // If the global is externally visible, put the initializer into a COMDAT
+    // group with the global being initialized.  On most platforms, this is a
+    // minor startup time optimization.  In the MS C++ ABI, there are no guard
+    // variables, so this COMDAT key is required for correctness.
+    AddGlobalCtor(Fn, 65535, COMDATKey);
     DelayedCXXInitPosition.erase(D);
   } else if (D->hasAttr<SelectAnyAttr>()) {
     // SelectAny globals will be comdat-folded. Put the initializer into a COMDAT
     // group associated with the global, so the initializers get folded too.
-    AddGlobalCtor(Fn, 65535, Key);
+    AddGlobalCtor(Fn, 65535, COMDATKey);
     DelayedCXXInitPosition.erase(D);
   } else {
     llvm::DenseMap<const Decl *, unsigned>::iterator I =