Add Win32 support to llvm::llvm_execute_on_thread(). Thanks to Aaron Ballman!

llvm-svn: 140011

1 files changed, 33 insertions, 2 deletions

diff --git a/llvm/lib/Support/Threading.cpp b/llvm/lib/Support/Threading.cpp
index 29579567ac6..bf432a9af71 100644
--- a/llvm/lib/Support/Threading.cpp
+++ b/llvm/lib/Support/Threading.cpp
@@ -102,13 +102,44 @@ void llvm::llvm_execute_on_thread(void (*Fn)(void*), void *UserData,
  error:
   ::pthread_attr_destroy(&Attr);
 }
+#elif defined(LLVM_MULTITHREADED) && defined(LLVM_ON_WIN32)
+#include "Windows/Windows.h"
+#include <process.h>
 
-#else
+struct ThreadInfo {
+  void (*func)(void*);
+  void *param;
+};
 
-// No non-pthread implementation, currently.
+static unsigned __stdcall ThreadCallback(void *param) {
+  struct ThreadInfo *info = reinterpret_cast<struct ThreadInfo *>(param);
+  info->func(info->param);
+
+  return 0;
+}
 
 void llvm::llvm_execute_on_thread(void (*Fn)(void*), void *UserData,
                                   unsigned RequestedStackSize) {
+  struct ThreadInfo param = { Fn, UserData };
+
+  HANDLE hThread = (HANDLE)::_beginthreadex(NULL,
+                                            RequestedStackSize, ThreadCallback,
+                                            &param, 0, NULL);
+
+  if (hThread) {
+    // We actually don't care whether the wait succeeds or fails, in
+    // the same way we don't care whether the pthread_join call succeeds
+    // or fails.  There's not much we could do if this were to fail. But
+    // on success, this call will wait until the thread finishes executing
+    // before returning.
+    (void)::WaitForSingleObject(hThread, INFINITE);
+    ::CloseHandle(hThread);
+  }
+}
+#else
+// Support for non-Win32, non-pthread implementation.
+void llvm::llvm_execute_on_thread(void (*Fn)(void*), void *UserData,
+                                  unsigned RequestedStackSize) {
   (void) RequestedStackSize;
   Fn(UserData);
 }