[asan] Give global metadata private linkage.

Internal linkage preserves names like "__asan_global_foo" which may
account to 2% of unstripped binary size.

llvm-svn: 299995

2 files changed, 7 insertions, 6 deletions

diff --git a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index a68f97cff0d..94cfc69ed55 100644
--- a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -1625,11 +1625,12 @@ void AddressSanitizerModule::SetComdatForGlobalMetadata(
 GlobalVariable *
 AddressSanitizerModule::CreateMetadataGlobal(Module &M, Constant *Initializer,
                                              StringRef OriginalName) {
-  GlobalVariable *Metadata =
-      new GlobalVariable(M, Initializer->getType(), false,
-                         GlobalVariable::InternalLinkage, Initializer,
-                         Twine("__asan_global_") +
-                             GlobalValue::getRealLinkageName(OriginalName));
+  auto Linkage = TargetTriple.isOSBinFormatMachO()
+                     ? GlobalVariable::InternalLinkage
+                     : GlobalVariable::PrivateLinkage;
+  GlobalVariable *Metadata = new GlobalVariable(
+      M, Initializer->getType(), false, Linkage, Initializer,
+      Twine("__asan_global_") + GlobalValue::getRealLinkageName(OriginalName));
   Metadata->setSection(getGlobalMetadataSection());
   return Metadata;
 }
diff --git a/llvm/test/Instrumentation/AddressSanitizer/global_metadata_windows.ll b/llvm/test/Instrumentation/AddressSanitizer/global_metadata_windows.ll
index 686b506a96c..27cbd61ef81 100644
--- a/llvm/test/Instrumentation/AddressSanitizer/global_metadata_windows.ll
+++ b/llvm/test/Instrumentation/AddressSanitizer/global_metadata_windows.ll
@@ -13,7 +13,7 @@ $mystr = comdat any
 
 ; CHECK: $dead_global = comdat noduplicates
 ; CHECK: @dead_global = local_unnamed_addr global { i32, [60 x i8] } { i32 42, [60 x i8] zeroinitializer }, comdat, align 32
-; CHECK: @__asan_global_dead_global = internal global { {{.*}} }, section ".ASAN$GL", comdat($dead_global), align 64
+; CHECK: @__asan_global_dead_global = private global { {{.*}} }, section ".ASAN$GL", comdat($dead_global), align 64
 
 @dead_global = local_unnamed_addr global i32 42, align 4
 @mystr = linkonce_odr unnamed_addr constant [5 x i8] c"main\00", comdat, align 1