Add back r201608, r201622, r201624 and r201625

r201608 made llvm corretly handle private globals with MachO. r201622 fixed
a bug in it and r201624 and r201625 were changes for using private linkage,
assuming that llvm would do the right thing.

They all got reverted because r201608 introduced a crash in LTO. This patch
includes a fix for that. The issue was that TargetLoweringObjectFile now has
to be initialized before we can mangle names of private globals. This is
trivially true during the normal codegen pipeline (the asm printer does it),
but LTO has to do it manually.

llvm-svn: 201700

1 files changed, 5 insertions, 11 deletions

diff --git a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index cf10af61d2d..ee2692dced5 100644
--- a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -561,19 +561,13 @@ static size_t TypeSizeToSizeIndex(uint32_t TypeSize) {
 static GlobalVariable *createPrivateGlobalForString(
     Module &M, StringRef Str, bool AllowMerging) {
   Constant *StrConst = ConstantDataArray::getString(M.getContext(), Str);
-  // 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;
+  // We use private linkage for module-local strings. If they can be merged
+  // with another one, we set the unnamed_addr attribute.
   GlobalVariable *GV =
       new GlobalVariable(M, StrConst->getType(), true,
-                         linkage, StrConst, kAsanGenPrefix);
-  if (AllowMerging) GV->setUnnamedAddr(true);
+                         GlobalValue::PrivateLinkage, StrConst, kAsanGenPrefix);
+  if (AllowMerging)
+    GV->setUnnamedAddr(true);
   GV->setAlignment(1);  // Strings may not be merged w/o setting align 1.
   return GV;
 }