Add a hack to avoid adding '\01' to asm names when possible. It would be

better for clang to always compute the right name, but for now this hack
fixes PR9177 and lets us build firefox with LTO :-)

llvm-svn: 125607

1 files changed, 12 insertions, 1 deletions

diff --git a/clang/lib/AST/ItaniumMangle.cpp b/clang/lib/AST/ItaniumMangle.cpp
index 7d641e45c1f..df6e39b2b3a 100644
--- a/clang/lib/AST/ItaniumMangle.cpp
+++ b/clang/lib/AST/ItaniumMangle.cpp
@@ -23,6 +23,7 @@
 #include "clang/AST/ExprCXX.h"
 #include "clang/Basic/ABI.h"
 #include "clang/Basic/SourceManager.h"
+#include "clang/Basic/TargetInfo.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Support/ErrorHandling.h"
@@ -328,7 +329,17 @@ void CXXNameMangler::mangle(const NamedDecl *D, llvm::StringRef Prefix) {
   // over all other naming in the .o file.
   if (const AsmLabelAttr *ALA = D->getAttr<AsmLabelAttr>()) {
     // If we have an asm name, then we use it as the mangling.
-    Out << '\01';  // LLVM IR Marker for __asm("foo")
+
+    // Adding the prefix can cause problems when one file has a "foo" and
+    // another has a "\01foo". That is known to happen on ELF with the
+    // tricks normally used for producing aliases (PR9177). Fortunately the
+    // llvm mangler on ELF is a nop, so we can just avoid adding the \01
+    // marker.
+    llvm::StringRef UserLabelPrefix =
+      getASTContext().Target.getUserLabelPrefix();
+    if (!UserLabelPrefix.empty())
+      Out << '\01';  // LLVM IR Marker for __asm("foo")
+
     Out << ALA->getLabel();
     return;
   }