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, 6 insertions, 0 deletions

diff --git a/src/passes/Print.cpp b/src/passes/Print.cpp
index 0bf61e784..b1e1240ae 100644
--- a/src/passes/Print.cpp
+++ b/src/passes/Print.cpp
@@ -268,6 +268,7 @@ struct PrintExpressionContents
       o << " offset=" << curr->offset;
     }
   }
+  void visitAtomicFence(AtomicFence* curr) { printMedium(o, "atomic.fence"); }
   void visitSIMDExtract(SIMDExtract* curr) {
     prepareColor(o);
     switch (curr->op) {
@@ -1505,6 +1506,11 @@ struct PrintSExpression : public OverriddenVisitor<PrintSExpression> {
     printFullLine(curr->notifyCount);
     decIndent();
   }
+  void visitAtomicFence(AtomicFence* curr) {
+    o << '(';
+    PrintExpressionContents(currFunction, o).visit(curr);
+    o << ')';
+  }
   void visitSIMDExtract(SIMDExtract* curr) {
     o << '(';
     PrintExpressionContents(currFunction, o).visit(curr);