3 files changed, 33 insertions, 32 deletions
diff --git a/llvm/lib/Support/Windows/Process.inc b/llvm/lib/Support/Windows/Process.inc
index 4b91f9f7fc6..3526e3dee6f 100644
--- a/llvm/lib/Support/Windows/Process.inc
+++ b/llvm/lib/Support/Windows/Process.inc
@@ -439,13 +439,6 @@ const char *Process::ResetColor() {
   return 0;
 }
 
-// Include GetLastError() in a fatal error message.
-static void ReportLastErrorFatal(const char *Msg) {
-  std::string ErrMsg;
-  MakeErrMsg(&ErrMsg, Msg);
-  report_fatal_error(ErrMsg);
-}
-
 unsigned Process::GetRandomNumber() {
   HCRYPTPROV HCPC;
   if (!::CryptAcquireContextW(&HCPC, NULL, NULL, PROV_RSA_FULL,
diff --git a/llvm/lib/Support/Windows/Threading.inc b/llvm/lib/Support/Windows/Threading.inc
index 96649472cc9..83b47ea1e3d 100644
--- a/llvm/lib/Support/Windows/Threading.inc
+++ b/llvm/lib/Support/Windows/Threading.inc
@@ -21,36 +21,36 @@
 #undef MemoryFence
 #endif
 
-namespace {
-  struct ThreadInfo {
-    void(*func)(void*);
-    void *param;
-  };
+static unsigned __stdcall threadFuncSync(void *Arg) {
+  SyncThreadInfo *TI = static_cast<SyncThreadInfo *>(Arg);
+  TI->UserFn(TI->UserData);
+  return 0;
 }
 
-static unsigned __stdcall ThreadCallback(void *param) {
-  struct ThreadInfo *info = reinterpret_cast<struct ThreadInfo *>(param);
-  info->func(info->param);
-
+static unsigned __stdcall threadFuncAsync(void *Arg) {
+  std::unique_ptr<AsyncThreadInfo> Info(static_cast<AsyncThreadInfo *>(Arg));
+  (*Info)();
   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);
+static void
+llvm_execute_on_thread_impl(_beginthreadex_proc_type ThreadFunc, void *Arg,
+                            llvm::Optional<unsigned> StackSizeInBytes,
+                            JoiningPolicy JP) {
+  HANDLE hThread = (HANDLE)::_beginthreadex(
+      NULL, StackSizeInBytes.getValueOr(0), ThreadFunc, Arg, 0, NULL);
+
+  if (!hThread) {
+    ReportLastErrorFatal("_beginthreadex failed");
+  }
+
+  if (JP == JoiningPolicy::Join) {
+    if (::WaitForSingleObject(hThread, INFINITE) == WAIT_FAILED) {
+      ReportLastErrorFatal("WaitForSingleObject failed");
+    }
+  }
+  if (::CloseHandle(hThread) == FALSE) {
+    ReportLastErrorFatal("CloseHandle failed");
   }
 }
 
diff --git a/llvm/lib/Support/Windows/WindowsSupport.h b/llvm/lib/Support/Windows/WindowsSupport.h
index 2e2e97430b7..bb7e79b8601 100644
--- a/llvm/lib/Support/Windows/WindowsSupport.h
+++ b/llvm/lib/Support/Windows/WindowsSupport.h
@@ -41,6 +41,7 @@
 #include "llvm/Support/Allocator.h"
 #include "llvm/Support/Chrono.h"
 #include "llvm/Support/Compiler.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/VersionTuple.h"
 #include <cassert>
 #include <string>
@@ -66,6 +67,13 @@ llvm::VersionTuple GetWindowsOSVersion();
 
 bool MakeErrMsg(std::string *ErrMsg, const std::string &prefix);
 
+// Include GetLastError() in a fatal error message.
+LLVM_ATTRIBUTE_NORETURN inline void ReportLastErrorFatal(const char *Msg) {
+  std::string ErrMsg;
+  MakeErrMsg(&ErrMsg, Msg);
+  llvm::report_fatal_error(ErrMsg);
+}
+
 template <typename HandleTraits>
 class ScopedHandle {
   typedef typename HandleTraits::handle_type handle_type;