7 files changed, 132 insertions, 61 deletions

diff --git a/llvm/lib/Support/CrashRecoveryContext.cpp b/llvm/lib/Support/CrashRecoveryContext.cpp
index 9d13fce9cc5..8d8529b474f 100644
--- a/llvm/lib/Support/CrashRecoveryContext.cpp
+++ b/llvm/lib/Support/CrashRecoveryContext.cpp
@@ -404,7 +404,10 @@ bool CrashRecoveryContext::RunSafelyOnThread(function_ref<void()> Fn,
                                              unsigned RequestedStackSize) {
   bool UseBackgroundPriority = hasThreadBackgroundPriority();
   RunSafelyOnThreadInfo Info = { Fn, this, UseBackgroundPriority, false };
-  llvm_execute_on_thread(RunSafelyOnThread_Dispatch, &Info, RequestedStackSize);
+  llvm_execute_on_thread(RunSafelyOnThread_Dispatch, &Info,
+                         RequestedStackSize == 0
+                             ? llvm::None
+                             : llvm::Optional<unsigned>(RequestedStackSize));
   if (CrashRecoveryContextImpl *CRC = (CrashRecoveryContextImpl *)Impl)
     CRC->setSwitchedThread();
   return Info.Result;
diff --git a/llvm/lib/Support/Threading.cpp b/llvm/lib/Support/Threading.cpp
index e5899a60f4d..48750cef5ec 100644
--- a/llvm/lib/Support/Threading.cpp
+++ b/llvm/lib/Support/Threading.cpp
@@ -12,6 +12,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Support/Threading.h"
+#include "llvm/ADT/Optional.h"
 #include "llvm/Config/config.h"
 #include "llvm/Support/Host.h"
 
@@ -39,8 +40,8 @@ bool llvm::llvm_is_multithreaded() {
     (!defined(_WIN32) && !defined(HAVE_PTHREAD_H))
 // Support for non-Win32, non-pthread implementation.
 void llvm::llvm_execute_on_thread(void (*Fn)(void *), void *UserData,
-                                  unsigned RequestedStackSize) {
-  (void)RequestedStackSize;
+                                  llvm::Optional<unsigned> StackSizeInBytes) {
+  (void)StackSizeInBytes;
   Fn(UserData);
 }
 
@@ -56,6 +57,25 @@ void llvm::set_thread_name(const Twine &Name) {}
 
 void llvm::get_thread_name(SmallVectorImpl<char> &Name) { Name.clear(); }
 
+#if LLVM_ENABLE_THREADS == 0
+void llvm::llvm_execute_on_thread_async(
+    llvm::unique_function<void()> Func,
+    llvm::Optional<unsigned> StackSizeInBytes) {
+  (void)Func;
+  (void)StackSizeInBytes;
+  report_fatal_error("Spawning a detached thread doesn't make sense with no "
+                     "threading support");
+}
+#else
+// Support for non-Win32, non-pthread implementation.
+void llvm::llvm_execute_on_thread_async(
+    llvm::unique_function<void()> Func,
+    llvm::Optional<unsigned> StackSizeInBytes) {
+  (void)StackSizeInBytes;
+  std::thread(std::move(Func)).detach();
+}
+#endif
+
 #else
 
 #include <thread>
@@ -84,6 +104,17 @@ unsigned llvm::hardware_concurrency() {
   return 1;
 }
 
+namespace {
+struct SyncThreadInfo {
+  void (*UserFn)(void *);
+  void *UserData;
+};
+
+using AsyncThreadInfo = llvm::unique_function<void()>;
+
+enum class JoiningPolicy { Join, Detach };
+} // namespace
+
 // Include the platform-specific parts of this class.
 #ifdef LLVM_ON_UNIX
 #include "Unix/Threading.inc"
@@ -92,4 +123,20 @@ unsigned llvm::hardware_concurrency() {
 #include "Windows/Threading.inc"
 #endif
 
+void llvm::llvm_execute_on_thread(void (*Fn)(void *), void *UserData,
+                                  llvm::Optional<unsigned> StackSizeInBytes) {
+
+  SyncThreadInfo Info = {Fn, UserData};
+  llvm_execute_on_thread_impl(threadFuncSync, &Info, StackSizeInBytes,
+                              JoiningPolicy::Join);
+}
+
+void llvm::llvm_execute_on_thread_async(
+    llvm::unique_function<void()> Func,
+    llvm::Optional<unsigned> StackSizeInBytes) {
+  llvm_execute_on_thread_impl(&threadFuncAsync,
+                              new AsyncThreadInfo(std::move(Func)),
+                              StackSizeInBytes, JoiningPolicy::Detach);
+}
+
 #endif
diff --git a/llvm/lib/Support/Unix/Threading.inc b/llvm/lib/Support/Unix/Threading.inc
index ed9a9656305..afb887fc109 100644
--- a/llvm/lib/Support/Unix/Threading.inc
+++ b/llvm/lib/Support/Unix/Threading.inc
@@ -10,6 +10,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "Unix.h"
+#include "llvm/ADT/ScopeExit.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/Twine.h"
 
@@ -40,47 +42,56 @@
 #include <unistd.h>      // For syscall()
 #endif
 
-namespace {
-  struct ThreadInfo {
-    void(*UserFn)(void *);
-    void *UserData;
-  };
+static void *threadFuncSync(void *Arg) {
+  SyncThreadInfo *TI = static_cast<SyncThreadInfo *>(Arg);
+  TI->UserFn(TI->UserData);
+  return nullptr;
 }
 
-static void *ExecuteOnThread_Dispatch(void *Arg) {
-  ThreadInfo *TI = reinterpret_cast<ThreadInfo*>(Arg);
-  TI->UserFn(TI->UserData);
+static void *threadFuncAsync(void *Arg) {
+  std::unique_ptr<AsyncThreadInfo> Info(static_cast<AsyncThreadInfo *>(Arg));
+  (*Info)();
   return nullptr;
 }
 
-void llvm::llvm_execute_on_thread(void(*Fn)(void*), void *UserData,
-  unsigned RequestedStackSize) {
-  ThreadInfo Info = { Fn, UserData };
-  pthread_attr_t Attr;
-  pthread_t Thread;
+static void
+llvm_execute_on_thread_impl(void *(*ThreadFunc)(void *), void *Arg,
+                            llvm::Optional<unsigned> StackSizeInBytes,
+                            JoiningPolicy JP) {
+  int errnum;
 
   // Construct the attributes object.
-  if (::pthread_attr_init(&Attr) != 0)
-    return;
+  pthread_attr_t Attr;
+  if ((errnum = ::pthread_attr_init(&Attr)) != 0) {
+    ReportErrnumFatal("pthread_attr_init failed", errnum);
+  }
+
+  auto AttrGuard = llvm::make_scope_exit([&] {
+    if ((errnum = ::pthread_attr_destroy(&Attr)) != 0) {
+      ReportErrnumFatal("pthread_attr_destroy failed", errnum);
+    }
+  });
 
   // Set the requested stack size, if given.
-  if (RequestedStackSize != 0) {
-    if (::pthread_attr_setstacksize(&Attr, RequestedStackSize) != 0)
-      goto error;
+  if (StackSizeInBytes) {
+    if ((errnum = ::pthread_attr_setstacksize(&Attr, *StackSizeInBytes)) != 0) {
+      ReportErrnumFatal("pthread_attr_setstacksize failed", errnum);
+    }
   }
 
   // Construct and execute the thread.
-  if (::pthread_create(&Thread, &Attr, ExecuteOnThread_Dispatch, &Info) != 0)
-    goto error;
-
-  // Wait for the thread and clean up.
-  ::pthread_join(Thread, nullptr);
+  pthread_t Thread;
+  if ((errnum = ::pthread_create(&Thread, &Attr, ThreadFunc, Arg)) != 0)
+    ReportErrnumFatal("pthread_create failed", errnum);
 
-error:
-  ::pthread_attr_destroy(&Attr);
+  if (JP == JoiningPolicy::Join) {
+    // Wait for the thread
+    if ((errnum = ::pthread_join(Thread, nullptr)) != 0) {
+      ReportErrnumFatal("pthread_join failed", errnum);
+    }
+  }
 }
 
-
 uint64_t llvm::get_threadid() {
 #if defined(__APPLE__)
   // Calling "mach_thread_self()" bumps the reference count on the thread
diff --git a/llvm/lib/Support/Unix/Unix.h b/llvm/lib/Support/Unix/Unix.h
index 86309b0567f..1fc9a414f74 100644
--- a/llvm/lib/Support/Unix/Unix.h
+++ b/llvm/lib/Support/Unix/Unix.h
@@ -21,6 +21,7 @@
 #include "llvm/Config/config.h"
 #include "llvm/Support/Chrono.h"
 #include "llvm/Support/Errno.h"
+#include "llvm/Support/ErrorHandling.h"
 #include <algorithm>
 #include <assert.h>
 #include <cerrno>
@@ -69,6 +70,14 @@ static inline bool MakeErrMsg(
   return true;
 }
 
+// Include StrError(errnum) in a fatal error message.
+LLVM_ATTRIBUTE_NORETURN static inline void ReportErrnumFatal(const char *Msg,
+                                                             int errnum) {
+  std::string ErrMsg;
+  MakeErrMsg(&ErrMsg, Msg, errnum);
+  llvm::report_fatal_error(ErrMsg);
+}
+
 namespace llvm {
 namespace sys {
 
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;