MC: Add support for disabling "temporary label" behavior. Useful for debugging
on Darwin.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128430 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/llvm-mc/llvm-mc.cpp b/tools/llvm-mc/llvm-mc.cpp
index b781866..f76b6ed 100644
--- a/tools/llvm-mc/llvm-mc.cpp
+++ b/tools/llvm-mc/llvm-mc.cpp
@@ -113,6 +113,10 @@
 NoInitialTextSection("n", cl::desc(
                    "Don't assume assembly file starts in the text section"));
 
+static cl::opt<bool>
+SaveTempLabels("L", cl::desc(
+                 "Don't discard temporary labels"));
+
 enum ActionType {
   AC_AsLex,
   AC_Assemble,
@@ -327,6 +331,8 @@
 
   const TargetAsmInfo *tai = new TargetAsmInfo(*TM);
   MCContext Ctx(*MAI, tai);
+  if (SaveTempLabels)
+    Ctx.setAllowTemporaryLabels(false);
 
   OwningPtr<tool_output_file> Out(GetOutputStream());
   if (!Out)