Subzero: Make thread_local work under MacOS 10.6.

src/IceCfg.cpp

@@ -25,7 +25,7 @@
 
 namespace Ice {
 
-thread_local const Cfg *Cfg::CurrentCfg = nullptr;
+ICE_ATTRIBUTE_TLS const Cfg *Cfg::CurrentCfg = nullptr;
 
 ArenaAllocator<> *getCurrentCfgAllocator() {
   return Cfg::getCurrentCfgAllocator();

src/IceCfg.h

@@ -213,7 +213,7 @@ private:
   // Maintain a pointer in TLS to the current Cfg being translated.
   // This is primarily for accessing its allocator statelessly, but
   // other uses are possible.
-  thread_local static const Cfg *CurrentCfg;
+  ICE_ATTRIBUTE_TLS static const Cfg *CurrentCfg;
 };
 
 } // end of namespace Ice

src/IceDefs.h

@@ -38,6 +38,15 @@
 #include "llvm/Support/ELF.h"
 #include "llvm/Support/raw_ostream.h"
 
+// TODO(stichnot): Define ICE_ATTRIBUTE_TLS as thread_local after all
+// compilers support that C++11 keyword.  In particular, MacOS 10.6
+// does not support it.
+#if defined (_MSC_VER)
+#define ICE_ATTRIBUTE_TLS __declspec(thread)
+#else // !_MSC_VER
+#define ICE_ATTRIBUTE_TLS __thread
+#endif // !_MSC_VER
+
 namespace Ice {
 
 class Assembler;

src/IceGlobalContext.cpp

@@ -518,6 +518,6 @@ TimerMarker::TimerMarker(TimerIdT ID, const Cfg *Func)
   }
 }
 
-thread_local GlobalContext::ThreadContext *GlobalContext::TLS;
+ICE_ATTRIBUTE_TLS GlobalContext::ThreadContext *GlobalContext::TLS;
 
 } // end of namespace Ice

src/IceGlobalContext.h

@@ -274,7 +274,7 @@ private:
   std::vector<ThreadContext *> AllThreadContexts;
   // Each thread has its own TLS pointer which is also held in
   // AllThreadContexts.
-  thread_local static ThreadContext *TLS;
+  ICE_ATTRIBUTE_TLS static ThreadContext *TLS;
 
   // Private helpers for mangleName()
   typedef llvm::SmallVector<char, 32> ManglerVector;