Merge pull request #682 from loganchien/fix-empty-deadlock

Fix asm2wasm dead lock caused by empty module

1 files changed, 11 insertions, 4 deletions

diff --git a/src/wasm-module-building.h b/src/wasm-module-building.h
index 3cdebc558..ead074991 100644
--- a/src/wasm-module-building.h
+++ b/src/wasm-module-building.h
@@ -86,7 +86,15 @@ class OptimizingIncrementalModuleBuilder {
 public:
   // numFunctions must be equal to the number of functions allocated, or higher. Knowing
   // this bounds helps avoid locking.
-  OptimizingIncrementalModuleBuilder(Module* wasm, Index numFunctions) : wasm(wasm), numFunctions(numFunctions), nextFunction(0), finishing(false) {
+  OptimizingIncrementalModuleBuilder(Module* wasm, Index numFunctions)
+      : wasm(wasm), numFunctions(numFunctions), endMarker(nullptr), list(nullptr), nextFunction(0),
+        numWorkers(0), liveWorkers(0), activeWorkers(0), availableFuncs(0), finishedFuncs(0),
+        finishing(false) {
+    if (numFunctions == 0) {
+      // special case: no functions to be optimized.  Don't create any threads.
+      return;
+    }
+
     // prepare work list
     endMarker = new Function();
     list = new std::atomic<Function*>[numFunctions];
@@ -139,7 +147,7 @@ public:
 private:
   void createWorker() {
     DEBUG_THREAD("create a worker");
-    threads.emplace_back(std::unique_ptr<std::thread>(new std::thread(workerMain, this)));
+    threads.emplace_back(make_unique<std::thread>(workerMain, this));
   }
 
   void wakeWorker() {
@@ -197,9 +205,8 @@ private:
     passRunner.runFunction(func);
   }
 
-  static void workerMain(void* param) {
+  static void workerMain(OptimizingIncrementalModuleBuilder* self) {
     DEBUG_THREAD("workerMain");
-    OptimizingIncrementalModuleBuilder* self = (OptimizingIncrementalModuleBuilder*)param;
     {
       std::lock_guard<std::mutex> lock(self->mutex);
       self->liveWorkers++;