PR42111: Use guarded initialization for thread-local variables with

unordered initialization and internal linkage.

We'll run their initializers once on each reference, so we need a guard
variable even though they only have a single definition.

llvm-svn: 362562

1 files changed, 7 insertions, 1 deletions

diff --git a/clang/lib/CodeGen/CGDeclCXX.cpp b/clang/lib/CodeGen/CGDeclCXX.cpp
index ce0163723c4..199e0ac99e8 100644
--- a/clang/lib/CodeGen/CGDeclCXX.cpp
+++ b/clang/lib/CodeGen/CGDeclCXX.cpp
@@ -630,7 +630,13 @@ void CodeGenFunction::GenerateCXXGlobalVarDeclInitFunc(llvm::Function *Fn,
   // Use guarded initialization if the global variable is weak. This
   // occurs for, e.g., instantiated static data members and
   // definitions explicitly marked weak.
-  if (Addr->hasWeakLinkage() || Addr->hasLinkOnceLinkage()) {
+  //
+  // Also use guarded initialization for a variable with dynamic TLS and
+  // unordered initialization. (If the initialization is ordered, the ABI
+  // layer will guard the whole-TU initialization for us.)
+  if (Addr->hasWeakLinkage() || Addr->hasLinkOnceLinkage() ||
+      (D->getTLSKind() == VarDecl::TLS_Dynamic &&
+       isTemplateInstantiation(D->getTemplateSpecializationKind()))) {
     EmitCXXGuardedInit(*D, Addr, PerformInit);
   } else {
     EmitCXXGlobalVarDeclInit(*D, Addr, PerformInit);