From 10251753b6897adcd22cc981c0cc42f348c109de Mon Sep 17 00:00:00 2001
From: Eric Christopher <echristo@gmail.com>
Date: Wed, 7 Aug 2013 21:13:06 +0000
Subject: [PATCH] Using the integrated assembler we'd fail to change section to
 the .tbss section for zerofill thread locals. Make sure we do this before
 emitting the zerofills.

Fixes PR15972.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187913 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/AsmPrinter/AsmPrinter.cpp |  5 +++--
 test/MC/MachO/tlv-bss.ll              | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+), 2 deletions(-)
 create mode 100644 test/MC/MachO/tlv-bss.ll

diff --git a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 0c59286fa95..12c35747ee4 100644
--- a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -368,9 +368,10 @@ void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
     MCSymbol *MangSym =
       OutContext.GetOrCreateSymbol(GVSym->getName() + Twine("$tlv$init"));
 
-    if (GVKind.isThreadBSS())
+    if (GVKind.isThreadBSS()) {
+      TheSection = getObjFileLowering().getTLSBSSSection();
       OutStreamer.EmitTBSSSymbol(TheSection, MangSym, Size, 1 << AlignLog);
-    else if (GVKind.isThreadData()) {
+    } else if (GVKind.isThreadData()) {
       OutStreamer.SwitchSection(TheSection);
 
       EmitAlignment(AlignLog, GV);
diff --git a/test/MC/MachO/tlv-bss.ll b/test/MC/MachO/tlv-bss.ll
new file mode 100644
index 00000000000..af620f9e304
--- /dev/null
+++ b/test/MC/MachO/tlv-bss.ll
@@ -0,0 +1,33 @@
+; RUN: llc -O0 -mtriple=x86_64-apple-darwin12 -filetype=obj -o - %s | macho-dump | FileCheck %s
+; Test that we emit weak_odr thread_locals correctly into the thread_bss section
+; PR15972
+
+; CHECK: __thread_bss
+; CHECK: 'size', 8
+; CHECK: 'alignment', 3
+; CHECK: __thread_vars
+
+; Generated from this C++ source
+; template<class T>
+; struct Tls {
+;   static __thread void* val;
+; };
+
+; template<class T> __thread void* Tls<T>::val;
+
+; void* f(int x) {
+;         return Tls<long>::val;
+; }
+
+@_ZN3TlsIlE3valE = weak_odr thread_local global i8* null, align 8
+
+; Function Attrs: nounwind ssp uwtable
+define i8* @_Z1fi(i32 %x) #0 {
+entry:
+  %x.addr = alloca i32, align 4
+  store i32 %x, i32* %x.addr, align 4
+  %0 = load i8** @_ZN3TlsIlE3valE, align 8
+  ret i8* %0
+}
+
+attributes #0 = { nounwind ssp uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf"="true" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
-- 
2.11.0