Unix/Process: Don't use pthread_sigmask if we aren't built with threads

[oota-llvm.git] / lib / Support / CrashRecoveryContext.cpp

diff --git a/lib/Support/CrashRecoveryContext.cpp b/lib/Support/CrashRecoveryContext.cpp
index 016c805cc7abe907b60b01203a61f51b68c46e43..9b0e44339d8411dddf387fcb3afabc7141b1a315 100644 (file)
--- a/lib/Support/CrashRecoveryContext.cpp
+++ b/lib/Support/CrashRecoveryContext.cpp
@@ -332,12 +332,26 @@ const std::string &CrashRecoveryContext::getBacktrace() const {
   return CRC->Backtrace;
 }
 
-//
+// FIXME: Portability.
+static void setThreadBackgroundPriority() {
+#ifdef __APPLE__
+  setpriority(PRIO_DARWIN_THREAD, 0, PRIO_DARWIN_BG);
+#endif
+}
+
+static bool hasThreadBackgroundPriority() {
+#ifdef __APPLE__
+  return getpriority(PRIO_DARWIN_THREAD, 0) == 1;
+#else
+  return false;
+#endif
+}
 
 namespace {
 struct RunSafelyOnThreadInfo {
   function_ref<void()> Fn;
   CrashRecoveryContext *CRC;
+  bool UseBackgroundPriority;
   bool Result;
 };
 }
@@ -345,11 +359,16 @@ struct RunSafelyOnThreadInfo {
 static void RunSafelyOnThread_Dispatch(void *UserData) {
   RunSafelyOnThreadInfo *Info =
     reinterpret_cast<RunSafelyOnThreadInfo*>(UserData);
+
+  if (Info->UseBackgroundPriority)
+    setThreadBackgroundPriority();
+
   Info->Result = Info->CRC->RunSafely(Info->Fn);
 }
 bool CrashRecoveryContext::RunSafelyOnThread(function_ref<void()> Fn,
                                              unsigned RequestedStackSize) {
-  RunSafelyOnThreadInfo Info = { Fn, this, false };
+  bool UseBackgroundPriority = hasThreadBackgroundPriority();
+  RunSafelyOnThreadInfo Info = { Fn, this, UseBackgroundPriority, false };
   llvm_execute_on_thread(RunSafelyOnThread_Dispatch, &Info, RequestedStackSize);
   if (CrashRecoveryContextImpl *CRC = (CrashRecoveryContextImpl *)Impl)
     CRC->setSwitchedThread();