Add atomic.fence instruction (#2307)

This adds `atomic.fence` instruction:
https://github.com/WebAssembly/threads/blob/master/proposals/threads/Overview.md#fence-operator

This also fix bugs in `atomic.wait` and `atomic.notify` instructions in
binaryen.js and adds tests for them.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/passes/RemoveUnusedModuleElements.cpp b/src/passes/RemoveUnusedModuleElements.cpp
index 20c30d271..d4c6d5a5d 100644
--- a/src/passes/RemoveUnusedModuleElements.cpp
+++ b/src/passes/RemoveUnusedModuleElements.cpp
@@ -106,6 +106,7 @@ struct ReachabilityAnalyzer : public PostWalker<ReachabilityAnalyzer> {
   void visitAtomicRMW(AtomicRMW* curr) { usesMemory = true; }
   void visitAtomicWait(AtomicWait* curr) { usesMemory = true; }
   void visitAtomicNotify(AtomicNotify* curr) { usesMemory = true; }
+  void visitAtomicFence(AtomicFence* curr) { usesMemory = true; }
   void visitMemoryInit(MemoryInit* curr) { usesMemory = true; }
   void visitDataDrop(DataDrop* curr) { usesMemory = true; }
   void visitMemoryCopy(MemoryCopy* curr) { usesMemory = true; }