Use ThreadLauncher to launch TaskPool threads

Summary:
This allows for the stack size to be configured, which isn't
possible with std::thread. Prevents overflowing the stack when
performing complex operations in the task pool on darwin,
where the default pthread stack size is only 512kb.

Reviewers: labath, tberghammer, clayborg

Subscribers: lldb-commits

Differential Revision: https://reviews.llvm.org/D37930

llvm-svn: 313537

lldb/source/Utility/TaskPool.cpp

@@ -8,6 +8,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "lldb/Utility/TaskPool.h"
+#include "lldb/Host/ThreadLauncher.h"
 
 #include <cstdint> // for uint32_t
 #include <queue>   // for queue
@@ -23,6 +24,8 @@ public:
 private:
   TaskPoolImpl();
 
+  static lldb::thread_result_t WorkerPtr(void *pool);
+
   static void Worker(TaskPoolImpl *pool);
 
   std::queue<std::function<void()>> m_tasks;
@@ -45,6 +48,7 @@ TaskPoolImpl::TaskPoolImpl() : m_thread_count(0) {}
 
 void TaskPoolImpl::AddTask(std::function<void()> &&task_fn) {
   static const uint32_t max_threads = std::thread::hardware_concurrency();
+  const size_t min_stack_size = 8 * 1024 * 1024;
 
   std::unique_lock<std::mutex> lock(m_tasks_mutex);
   m_tasks.emplace(std::move(task_fn));
@@ -54,10 +58,17 @@ void TaskPoolImpl::AddTask(std::function<void()> &&task_fn) {
     // This prevents the thread
     // from exiting prematurely and triggering a linux libc bug
     // (https://sourceware.org/bugzilla/show_bug.cgi?id=19951).
-    std::thread(Worker, this).detach();
+    lldb_private::ThreadLauncher::LaunchThread("task-pool.worker", WorkerPtr,
+                                               this, nullptr, min_stack_size)
+        .Release();
   }
 }
 
+lldb::thread_result_t TaskPoolImpl::WorkerPtr(void *pool) {
+  Worker((TaskPoolImpl *)pool);
+  return 0;
+}
+
 void TaskPoolImpl::Worker(TaskPoolImpl *pool) {
   while (true) {
     std::unique_lock<std::mutex> lock(pool->m_tasks_mutex);