r197193 - [-cxx-abi microsoft] Add commentary for mangleStaticGuardVariable

[David Majnemer]

Author: majnemer
Date: Thu Dec 12 18:52:45 2013
New Revision: 197193

URL: http://llvm.org/viewvc/llvm-project?rev=197193&view=rev
Log:
[-cxx-abi microsoft] Add commentary for mangleStaticGuardVariable

We will need to do some work here if we want to play nice with MSVC2013.
Add a TODO indicating what changed and why this matters.

Modified:
    cfe/trunk/lib/AST/MicrosoftMangle.cpp

Modified: cfe/trunk/lib/AST/MicrosoftMangle.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/MicrosoftMangle.cpp?rev=197193&r1=197192&r2=197193&view=diff
==============================================================================
--- cfe/trunk/lib/AST/MicrosoftMangle.cpp (original)
+++ cfe/trunk/lib/AST/MicrosoftMangle.cpp Thu Dec 12 18:52:45 2013
@@ -2048,6 +2048,15 @@ void MicrosoftMangleContextImpl::mangleR
 
 void MicrosoftMangleContextImpl::mangleStaticGuardVariable(const VarDecl *VD,
                                                            raw_ostream &Out) {
+  // TODO: This is not correct, especially with respect to MSVC2013.  MSVC2013
+  // utilizes thread local variables to implement thread safe, re-entrant
+  // initialization for statics.  They no longer differentiate between an
+  // externally visible and non-externally visible static with respect to
+  // mangling, they all get $TSS <number>.
+  //
+  // N.B. This means that they can get more than 32 static variable guards in a
+  // scope.  It also means that they broke compatibility with their own ABI.
+
   // <guard-name> ::= ?_B <postfix> @51
   //              ::= ?$S <guard-num> @ <postfix> @4IA