From 0732e9437825550e65aab45050423cb87da55850 Mon Sep 17 00:00:00 2001
From: Rafael Espindola <rafael.espindola@gmail.com>
Date: Fri, 7 Feb 2014 16:21:30 +0000
Subject: [PATCH] Fix a bug with .weak_def_can_be_hidden: Mutable variables
 cannot use it.

Thanks to John McCall for noticing it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200977 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/AsmPrinter/AsmPrinter.cpp         | 12 ++++++++++
 .../CodeGen/PowerPC/weak_def_can_be_hidden.ll | 24 ++++++++++++++-----
 test/CodeGen/X86/weak_def_can_be_hidden.ll    | 24 ++++++++++++++-----
 3 files changed, 48 insertions(+), 12 deletions(-)

diff --git a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 141a6686304..89da65eb3fb 100644
--- a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -245,6 +245,18 @@ static bool canBeHidden(const GlobalValue *GV, const MCAsmInfo &MAI) {
   if (GV->hasUnnamedAddr())
     return true;
 
+  // This is only used for MachO, so right now it doesn't really matter how
+  // we handle alias. Revisit this once the MachO linker implements aliases.
+  if (isa<GlobalAlias>(GV))
+    return false;
+
+  // If it is a non constant variable, it needs to be uniqued across shared
+  // objects.
+  if (const GlobalVariable *Var = dyn_cast<GlobalVariable>(GV)) {
+    if (!Var->isConstant())
+      return false;
+  }
+
   GlobalStatus GS;
   if (!GlobalStatus::analyzeGlobal(GV, GS) && !GS.IsCompared)
     return true;
diff --git a/test/CodeGen/PowerPC/weak_def_can_be_hidden.ll b/test/CodeGen/PowerPC/weak_def_can_be_hidden.ll
index 130d8faaf8b..e038b3f2fb2 100644
--- a/test/CodeGen/PowerPC/weak_def_can_be_hidden.ll
+++ b/test/CodeGen/PowerPC/weak_def_can_be_hidden.ll
@@ -3,7 +3,7 @@
 ; RUN: llc -mtriple=powerpc-apple-darwin9 -O0 < %s | FileCheck --check-prefix=CHECK-D89 %s
 ; RUN: llc -mtriple=powerpc-apple-darwin8 -O0 < %s | FileCheck --check-prefix=CHECK-D89 %s
 
-@v1 = linkonce_odr global i32 32
+@v1 = linkonce_odr constant i32 32
 ; CHECK: .globl  _v1
 ; CHECK: .weak_def_can_be_hidden _v1
 
@@ -15,13 +15,17 @@ define i32 @f1() {
   ret i32 %x
 }
 
-@v2 = linkonce_odr global i32 32
+@v2 = linkonce_odr constant i32 32
 ; CHECK: .globl  _v2
 ; CHECK: .weak_definition _v2
 
 ; CHECK-D89: .globl  _v2
 ; CHECK-D89: .weak_definition _v2
 
+define i32* @f2() {
+  ret i32* @v2
+}
+
 @v3 = linkonce_odr unnamed_addr global i32 32
 ; CHECK: .globl  _v3
 ; CHECK: .weak_def_can_be_hidden _v3
@@ -29,10 +33,18 @@ define i32 @f1() {
 ; CHECK-D89: .globl  _v3
 ; CHECK-D89: .weak_definition _v3
 
-define i32* @f2() {
-  ret i32* @v2
-}
-
 define i32* @f3() {
   ret i32* @v3
 }
+
+@v4 = linkonce_odr global i32 32
+; CHECK: .globl  _v4
+; CHECK: .weak_definition _v4
+
+; CHECK-D89: .globl  _v4
+; CHECK-D89: .weak_definition _v4
+
+define i32 @f4() {
+  %x = load i32 * @v4
+  ret i32 %x
+}
diff --git a/test/CodeGen/X86/weak_def_can_be_hidden.ll b/test/CodeGen/X86/weak_def_can_be_hidden.ll
index 22aa135e65e..b17f372afed 100644
--- a/test/CodeGen/X86/weak_def_can_be_hidden.ll
+++ b/test/CodeGen/X86/weak_def_can_be_hidden.ll
@@ -4,7 +4,7 @@
 ; RUN: llc -mtriple=i686-apple-darwin9 -O0 < %s | FileCheck --check-prefix=CHECK-D89 %s
 ; RUN: llc -mtriple=i686-apple-darwin8 -O0 < %s | FileCheck --check-prefix=CHECK-D89 %s
 
-@v1 = linkonce_odr global i32 32
+@v1 = linkonce_odr constant i32 32
 ; CHECK: .globl  _v1
 ; CHECK: .weak_def_can_be_hidden _v1
 
@@ -16,13 +16,17 @@ define i32 @f1() {
   ret i32 %x
 }
 
-@v2 = linkonce_odr global i32 32
+@v2 = linkonce_odr constant i32 32
 ; CHECK: .globl  _v2
 ; CHECK: .weak_definition _v2
 
 ; CHECK-D89: .globl  _v2
 ; CHECK-D89: .weak_definition _v2
 
+define i32* @f2() {
+  ret i32* @v2
+}
+
 @v3 = linkonce_odr unnamed_addr global i32 32
 ; CHECK: .globl  _v3
 ; CHECK: .weak_def_can_be_hidden _v3
@@ -30,10 +34,18 @@ define i32 @f1() {
 ; CHECK-D89: .globl  _v3
 ; CHECK-D89: .weak_definition _v3
 
-define i32* @f2() {
-  ret i32* @v2
-}
-
 define i32* @f3() {
   ret i32* @v3
 }
+
+@v4 = linkonce_odr global i32 32
+; CHECK: .globl  _v4
+; CHECK: .weak_definition _v4
+
+; CHECK-D89: .globl  _v4
+; CHECK-D89: .weak_definition _v4
+
+define i32 @f4() {
+  %x = load i32 * @v4
+  ret i32 %x
+}
-- 
2.34.1