Ifdef out more code with LLVM_ENABLE_THREADS, mxe doesn't include definitions of std::mutex etc.

Author: vargaz

llvm/include/llvm/Support/ThreadPool.h

@@ -48,6 +48,7 @@ class ThreadPool {
   /// Blocking destructor: the pool will wait for all the threads to complete.
   ~ThreadPool();
 
+#if LLVM_ENABLE_THREADS
   /// Asynchronous submission of a task to the pool. The returned future can be
   /// used to wait for the task to finish and is *non-blocking* on destruction.
   template <typename Function, typename... Args>
@@ -63,6 +64,15 @@ class ThreadPool {
   inline std::shared_future<void> async(Function &&F) {
     return asyncImpl(std::forward<Function>(F));
   }
+#else
+  template <typename Function, typename... Args>
+  inline void async(Function &&F, Args &&... ArgList) {
+  }
+
+  template <typename Function>
+  inline void async(Function &&F) {
+  }
+#endif
 
   /// Blocking wait for all the threads to complete and the queue to be empty.
   /// It is an error to try to add new tasks while blocking on this call.
@@ -79,13 +89,15 @@ class ThreadPool {
   /// Tasks waiting for execution in the pool.
   std::queue<PackagedTaskTy> Tasks;
 
+#if LLVM_ENABLE_THREADS
   /// Locking and signaling for accessing the Tasks queue.
   std::mutex QueueLock;
   std::condition_variable QueueCondition;
 
   /// Locking and signaling for job completion
   std::mutex CompletionLock;
   std::condition_variable CompletionCondition;
+#endif
 
   /// Keep track of the number of thread actually busy
   std::atomic<unsigned> ActiveThreads;

llvm/lib/LTO/LTO.cpp

@@ -859,7 +859,9 @@ class InProcessThinBackend : public ThinBackendProc {
   std::set<GlobalValue::GUID> CfiFunctionDecls;
 
   Optional<Error> Err;
+#if LLVM_ENABLE_THREADS
   std::mutex ErrMu;
+#endif
 
 public:
   InProcessThinBackend(
@@ -946,7 +948,9 @@ class InProcessThinBackend : public ThinBackendProc {
               AddStream, Cache, Task, BM, CombinedIndex, ImportList, ExportList,
               ResolvedODR, DefinedGlobals, ModuleMap, TypeIdSummariesByGuid);
           if (E) {
+#if LLVM_ENABLE_THREADS
             std::unique_lock<std::mutex> L(ErrMu);
+#endif
             if (Err)
               Err = joinErrors(std::move(*Err), std::move(E));
             else

llvm/lib/Support/ThreadPool.cpp

@@ -11,8 +11,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/Support/ThreadPool.h"
-
 #include "llvm/Config/llvm-config.h"
 #include "llvm/Support/Threading.h"
 #include "llvm/Support/raw_ostream.h"
@@ -21,6 +19,8 @@ using namespace llvm;
 
 #if LLVM_ENABLE_THREADS
 
+#include "llvm/Support/ThreadPool.h"
+
 // Default to hardware_concurrency
 ThreadPool::ThreadPool() : ThreadPool(hardware_concurrency()) {}
 
@@ -109,6 +109,8 @@ ThreadPool::~ThreadPool() {
 
 #else // LLVM_ENABLE_THREADS Disabled
 
+#if 0
+
 ThreadPool::ThreadPool() : ThreadPool(0) {}
 
 // No threads are launched, issue a warning if ThreadCount is not 0
@@ -144,3 +146,5 @@ ThreadPool::~ThreadPool() {
 }
 
 #endif
+
+#endif