Support: add llvm::thread class that supports specifying stack size.

This adds a new llvm::thread class with the same interface as std::thread
except there is an extra constructor that allows us to set the new thread's
stack size. On Darwin even the default size is boosted to 8MB to match the main
thread.

It also switches all users of the older C-style `llvm_execute_on_thread` API
family over to `llvm::thread` followed by either a `detach` or `join` call and
removes the old API.

1 files changed, 7 insertions, 4 deletions

diff --git a/llvm/lib/Support/CrashRecoveryContext.cpp b/llvm/lib/Support/CrashRecoveryContext.cpp
index 3ee6a4fd36f4..433d99df5932 100644
--- a/llvm/lib/Support/CrashRecoveryContext.cpp
+++ b/llvm/lib/Support/CrashRecoveryContext.cpp
@@ -13,6 +13,7 @@
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/Signals.h"
 #include "llvm/Support/ThreadLocal.h"
+#include "llvm/Support/thread.h"
 #include <mutex>
 #include <setjmp.h>
 
@@ -500,10 +501,12 @@ 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 == 0
-                             ? llvm::None
-                             : llvm::Optional<unsigned>(RequestedStackSize));
+  llvm::thread Thread(RequestedStackSize == 0
+                          ? llvm::None
+                          : llvm::Optional<unsigned>(RequestedStackSize),
+                      RunSafelyOnThread_Dispatch, &Info);
+  Thread.join();
+
   if (CrashRecoveryContextImpl *CRC = (CrashRecoveryContextImpl *)Impl)
     CRC->setSwitchedThread();
   return Info.Result;