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/ir/ExpressionAnalyzer.cpp b/src/ir/ExpressionAnalyzer.cpp
index f8f96d5c8..a52d7af90 100644
--- a/src/ir/ExpressionAnalyzer.cpp
+++ b/src/ir/ExpressionAnalyzer.cpp
@@ -180,6 +180,7 @@ template<typename T> void visitImmediates(Expression* curr, T& visitor) {
     void visitAtomicNotify(AtomicNotify* curr) {
       visitor.visitAddress(curr->offset);
     }
+    void visitAtomicFence(AtomicFence* curr) { visitor.visitInt(curr->order); }
     void visitSIMDExtract(SIMDExtract* curr) {
       visitor.visitInt(curr->op);
       visitor.visitInt(curr->index);