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, 4 insertions, 0 deletions

diff --git a/src/wasm/wasm-s-parser.cpp b/src/wasm/wasm-s-parser.cpp
index 39f6b0a9f..3a1e0db09 100644
--- a/src/wasm/wasm-s-parser.cpp
+++ b/src/wasm/wasm-s-parser.cpp
@@ -1421,6 +1421,10 @@ Expression* SExpressionWasmBuilder::makeAtomicNotify(Element& s) {
   return ret;
 }
 
+Expression* SExpressionWasmBuilder::makeAtomicFence(Element& s) {
+  return allocator.alloc<AtomicFence>();
+}
+
 static uint8_t parseLaneIndex(const Element* s, size_t lanes) {
   const char* str = s->c_str();
   char* end;