[llvm] df9d64e - [IR] Add missing GlobalAlias copying of ThreadLocalMode attribute

[Teresa Johnson via llvm-commits]

Author: Itay Bookstein
Date: 2020-06-16T20:15:27-07:00
New Revision: df9d64ed9c1d819bc0a040e3ef4c4a4003bf5c93

URL: https://github.com/llvm/llvm-project/commit/df9d64ed9c1d819bc0a040e3ef4c4a4003bf5c93
DIFF: https://github.com/llvm/llvm-project/commit/df9d64ed9c1d819bc0a040e3ef4c4a4003bf5c93.diff

LOG: [IR] Add missing GlobalAlias copying of ThreadLocalMode attribute

Summary:
Previously, GlobalAlias::copyAttributesFrom did not preserve ThreadLocalMode,
causing incorrect IR generation in IR linking flows. This patch pushes the code
responsible for copying this attribute from GlobalVariable::copyAttributesFrom
down to GlobalValue::copyAttributesFrom so that it is shared by GlobalAlias.
Fixes PR46297.

Reviewers: tejohnson, pcc, hans

Reviewed By: tejohnson, hans

Subscribers: hiraditya, ibookstein, dexonsmith, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D81605

Added: 
    llvm/test/Linker/Inputs/alias-threadlocal-defs.ll
    llvm/test/Linker/alias-threadlocal.ll

Modified: 
    llvm/lib/IR/Globals.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/IR/Globals.cpp b/llvm/lib/IR/Globals.cpp
index eefd221ec389..34c767ff3672 100644
--- a/llvm/lib/IR/Globals.cpp
+++ b/llvm/lib/IR/Globals.cpp
@@ -65,6 +65,7 @@ Value *GlobalValue::handleOperandChangeImpl(Value *From, Value *To) {
 void GlobalValue::copyAttributesFrom(const GlobalValue *Src) {
   setVisibility(Src->getVisibility());
   setUnnamedAddr(Src->getUnnamedAddr());
+  setThreadLocalMode(Src->getThreadLocalMode());
   setDLLStorageClass(Src->getDLLStorageClass());
   setDSOLocal(Src->isDSOLocal());
   setPartition(Src->getPartition());
@@ -419,7 +420,6 @@ void GlobalVariable::setInitializer(Constant *InitVal) {
 /// from the GlobalVariable Src to this one.
 void GlobalVariable::copyAttributesFrom(const GlobalVariable *Src) {
   GlobalObject::copyAttributesFrom(Src);
-  setThreadLocalMode(Src->getThreadLocalMode());
   setExternallyInitialized(Src->isExternallyInitialized());
   setAttributes(Src->getAttributes());
 }

diff  --git a/llvm/test/Linker/Inputs/alias-threadlocal-defs.ll b/llvm/test/Linker/Inputs/alias-threadlocal-defs.ll
new file mode 100644
index 000000000000..7b7062cc3cd1
--- /dev/null
+++ b/llvm/test/Linker/Inputs/alias-threadlocal-defs.ll
@@ -0,0 +1,2 @@
+ at tlsvar1 = thread_local global i32 0, align 4
+ at tlsvar2 = hidden thread_local alias i32, i32* @tlsvar1

diff  --git a/llvm/test/Linker/alias-threadlocal.ll b/llvm/test/Linker/alias-threadlocal.ll
new file mode 100644
index 000000000000..3e50a62770b0
--- /dev/null
+++ b/llvm/test/Linker/alias-threadlocal.ll
@@ -0,0 +1,9 @@
+; RUN: llvm-link %s %p/Inputs/alias-threadlocal-defs.ll -S -o - | FileCheck %s
+
+; PR46297
+; Verify that linking GlobalAliases preserves the thread_local attribute
+
+; CHECK: @tlsvar1 = thread_local global i32 0, align 4
+; CHECK: @tlsvar2 = hidden thread_local alias i32, i32* @tlsvar1
+
+ at tlsvar2 = external thread_local global i32, align 4