TLS for MinGW

[yaron.keren]

Summary

Patch by Martell Malone (posted cfe-commits)

[yaron.keren]

It looks like LLVM has TLS support, in lib\Target\X86\X86ISelLowering.cpp:8550

if (Subtarget->isTargetKnownWindowsMSVC() ||
    Subtarget->isTargetWindowsGNU()) {
  // Just use the implicit TLS architecture

and test\CodeGen\X86\tls* do test for triple==x86-pc-win32, x86_64-pc-win32

[martell]

yaron FYI the mingw triplets have been changed to "windows-gnu" by compnerd

[yaron.keren]

Hi Martell,

Yes I know of the change, these are just the triples from the test which I did not modify.
The triples could be updated for new style in all tests but this is other decision to make.

[rnk]

Nice, LGTM.

Clang now compiles thread variables correctly on Windows for me. C++11 thread_local and declpsec(thread) need more work though.

[yaron.keren]

Committed by rnk in r207470.

clang-3.4/lib/Basic/Targets.cpp

 public:
   WindowsX86_32TargetInfo(const llvm::Triple &Triple)
       : WindowsTargetInfo<X86_32TargetInfo>(Triple) {
-    TLSSupported = false;
+    TLSSupported = true;
     WCharType = UnsignedShort;
     DoubleAlign = LongLongAlign = 64;
     DescriptionString = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-"

 public:
   WindowsX86_64TargetInfo(const llvm::Triple &Triple)
       : WindowsTargetInfo<X86_64TargetInfo>(Triple) {
-    TLSSupported = false;
+    TLSSupported = true;
     WCharType = UnsignedShort;
     LongWidth = LongAlign = 32;
     DoubleAlign = LongLongAlign = 64;