Remove the DW_AT_MIPS_linkage name attribute when we don't need it
output (we're emitting a specification already and the information
isn't changing) and we're not in old gdb compat mode.

Saves 1% on the debug information for a build of llvm.

Fixes rdar://11043421

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162493 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
index d30e5bb..7a3eb32 100644
--- a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -1028,8 +1028,10 @@
   // AT_specification code in order to work around a bug in older
   // gdbs that requires the linkage name to resolve multiple template
   // functions.
+  // TODO: Remove this set of code when we get rid of the old gdb
+  // compatibility.
   StringRef LinkageName = SP.getLinkageName();
-  if (!LinkageName.empty())
+  if (!LinkageName.empty() && DD->useDarwinGDBCompat())
     addString(SPDie, dwarf::DW_AT_MIPS_linkage_name,
               getRealLinkageName(LinkageName));
 
@@ -1043,6 +1045,11 @@
     return SPDie;
   }
 
+  // Add the linkage name if we have one.
+  if (!LinkageName.empty() && !DD->useDarwinGDBCompat())
+    addString(SPDie, dwarf::DW_AT_MIPS_linkage_name,
+              getRealLinkageName(LinkageName));
+
   // Constructors and operators for anonymous aggregates do not have names.
   if (!SP.getName().empty())
     addString(SPDie, dwarf::DW_AT_name, SP.getName());