This reverts commit r201625 and r201624.

Since r201608 got reverted, it is not safe to use private linkage in these cases
until it is committed back.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@201688 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 13 insertions, 8 deletions

diff --git a/examples/ExceptionDemo/ExceptionDemo.cpp b/examples/ExceptionDemo/ExceptionDemo.cpp
index d997cc55a9..be357730e6 100644
--- a/examples/ExceptionDemo/ExceptionDemo.cpp
+++ b/examples/ExceptionDemo/ExceptionDemo.cpp
@@ -915,7 +915,7 @@ void generateStringPrint(llvm::LLVMContext &context,
     new llvm::GlobalVariable(module,
                              stringConstant->getType(),
                              true,
-                             llvm::GlobalValue::PrivateLinkage,
+                             llvm::GlobalValue::LinkerPrivateLinkage,
                              stringConstant,
                              "");
   }
@@ -959,7 +959,7 @@ void generateIntegerPrint(llvm::LLVMContext &context,
     new llvm::GlobalVariable(module,
                              stringConstant->getType(),
                              true,
-                             llvm::GlobalValue::PrivateLinkage,
+                             llvm::GlobalValue::LinkerPrivateLinkage,
                              stringConstant,
                              "");
   }
diff --git a/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index ee2692dced..cf10af61d2 100644
--- a/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -561,13 +561,19 @@ static size_t TypeSizeToSizeIndex(uint32_t TypeSize) {
 static GlobalVariable *createPrivateGlobalForString(
     Module &M, StringRef Str, bool AllowMerging) {
   Constant *StrConst = ConstantDataArray::getString(M.getContext(), Str);
-  // We use private linkage for module-local strings. If they can be merged
-  // with another one, we set the unnamed_addr attribute.
+  // For module-local strings that can be merged with another one we set the
+  // private linkage and the unnamed_addr attribute.
+  // Non-mergeable strings are made linker_private to remove them from the
+  // symbol table. "private" linkage doesn't work for Darwin, where the
+  // "L"-prefixed globals  end up in __TEXT,__const section
+  // (see http://llvm.org/bugs/show_bug.cgi?id=17976 for more info).
+  GlobalValue::LinkageTypes linkage =
+      AllowMerging ? GlobalValue::PrivateLinkage
+                   : GlobalValue::LinkerPrivateLinkage;
   GlobalVariable *GV =
       new GlobalVariable(M, StrConst->getType(), true,
-                         GlobalValue::PrivateLinkage, StrConst, kAsanGenPrefix);
-  if (AllowMerging)
-    GV->setUnnamedAddr(true);
+                         linkage, StrConst, kAsanGenPrefix);
+  if (AllowMerging) GV->setUnnamedAddr(true);
   GV->setAlignment(1);  // Strings may not be merged w/o setting align 1.
   return GV;
 }
diff --git a/test/Instrumentation/AddressSanitizer/instrument_global.ll b/test/Instrumentation/AddressSanitizer/instrument_global.ll
index 7945e816ca..4717277b9a 100644
--- a/test/Instrumentation/AddressSanitizer/instrument_global.ll
+++ b/test/Instrumentation/AddressSanitizer/instrument_global.ll
@@ -7,7 +7,6 @@ target triple = "x86_64-unknown-linux-gnu"
 ; module ctor/dtor
 
 ; CHECK: llvm.global_ctors
-; CHECK: @__asan_gen_ = private constant [8 x i8] c"<stdin>\00", align 1
 ; CHECK: llvm.global_dtors
 
 ; Test that we don't instrument global arrays with static initializer