Import LLVM 10.0.0 release including clang, lld and lldb.

ok hackroom
tested by plenty

1 files changed, 126 insertions, 0 deletions

diff --git a/gnu/llvm/lldb/source/Host/common/TaskPool.cpp b/gnu/llvm/lldb/source/Host/common/TaskPool.cpp
new file mode 100644
index 00000000000..73f761b5cf6
--- /dev/null
+++ b/gnu/llvm/lldb/source/Host/common/TaskPool.cpp
@@ -0,0 +1,126 @@
+//===--------------------- TaskPool.cpp -------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "lldb/Host/TaskPool.h"
+#include "lldb/Host/ThreadLauncher.h"
+#include "lldb/Utility/Log.h"
+
+#include <cstdint>
+#include <queue>
+#include <thread>
+
+namespace lldb_private {
+
+namespace {
+class TaskPoolImpl {
+public:
+  static TaskPoolImpl &GetInstance();
+
+  void AddTask(std::function<void()> &&task_fn);
+
+private:
+  TaskPoolImpl();
+
+  static lldb::thread_result_t WorkerPtr(void *pool);
+
+  static void Worker(TaskPoolImpl *pool);
+
+  std::queue<std::function<void()>> m_tasks;
+  std::mutex m_tasks_mutex;
+  uint32_t m_thread_count;
+};
+
+} // end of anonymous namespace
+
+TaskPoolImpl &TaskPoolImpl::GetInstance() {
+  static TaskPoolImpl g_task_pool_impl;
+  return g_task_pool_impl;
+}
+
+void TaskPool::AddTaskImpl(std::function<void()> &&task_fn) {
+  TaskPoolImpl::GetInstance().AddTask(std::move(task_fn));
+}
+
+TaskPoolImpl::TaskPoolImpl() : m_thread_count(0) {}
+
+unsigned GetHardwareConcurrencyHint() {
+  // std::thread::hardware_concurrency may return 0 if the value is not well
+  // defined or not computable.
+  static const unsigned g_hardware_concurrency = 
+    std::max(1u, std::thread::hardware_concurrency());
+  return g_hardware_concurrency;
+}
+
+void TaskPoolImpl::AddTask(std::function<void()> &&task_fn) {
+  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));
+  if (m_thread_count < GetHardwareConcurrencyHint()) {
+    m_thread_count++;
+    // Note that this detach call needs to happen with the m_tasks_mutex held.
+    // This prevents the thread from exiting prematurely and triggering a linux
+    // libc bug (https://sourceware.org/bugzilla/show_bug.cgi?id=19951).
+    llvm::Expected<HostThread> host_thread =
+        lldb_private::ThreadLauncher::LaunchThread(
+            "task-pool.worker", WorkerPtr, this, min_stack_size);
+    if (host_thread) {
+      host_thread->Release();
+    } else {
+      LLDB_LOG(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST),
+               "failed to launch host thread: {}",
+               llvm::toString(host_thread.takeError()));
+    }
+  }
+}
+
+lldb::thread_result_t TaskPoolImpl::WorkerPtr(void *pool) {
+  Worker((TaskPoolImpl *)pool);
+  return {};
+}
+
+void TaskPoolImpl::Worker(TaskPoolImpl *pool) {
+  while (true) {
+    std::unique_lock<std::mutex> lock(pool->m_tasks_mutex);
+    if (pool->m_tasks.empty()) {
+      pool->m_thread_count--;
+      break;
+    }
+
+    std::function<void()> f = std::move(pool->m_tasks.front());
+    pool->m_tasks.pop();
+    lock.unlock();
+
+    f();
+  }
+}
+
+void TaskMapOverInt(size_t begin, size_t end,
+                    const llvm::function_ref<void(size_t)> &func) {
+  const size_t num_workers = std::min<size_t>(end, GetHardwareConcurrencyHint());
+  std::atomic<size_t> idx{begin};
+  
+  auto wrapper = [&idx, end, &func]() {
+    while (true) {
+      size_t i = idx.fetch_add(1);
+      if (i >= end)
+        break;
+      func(i);
+    }
+  };
+
+  std::vector<std::future<void>> futures;
+  futures.reserve(num_workers);
+  for (size_t i = 0; i < num_workers; i++)
+    futures.push_back(TaskPool::AddTask(wrapper));
+  for (size_t i = 0; i < num_workers; i++)
+    futures[i].wait();
+}
+
+} // namespace lldb_private
+