5 files changed, 44 insertions, 0 deletions
diff --git a/src/wasm/wasm-binary.cpp b/src/wasm/wasm-binary.cpp
index d75973ab0..b7daeda5a 100644
--- a/src/wasm/wasm-binary.cpp
+++ b/src/wasm/wasm-binary.cpp
@@ -2302,6 +2302,9 @@ BinaryConsts::ASTNodes WasmBinaryBuilder::readExpression(Expression*& curr) {
       if (maybeVisitAtomicNotify(curr, code)) {
         break;
       }
+      if (maybeVisitAtomicFence(curr, code)) {
+        break;
+      }
       throwError("invalid code after atomic prefix: " + std::to_string(code));
       break;
     }
@@ -3172,6 +3175,20 @@ bool WasmBinaryBuilder::maybeVisitAtomicNotify(Expression*& out, uint8_t code) {
   return true;
 }
 
+bool WasmBinaryBuilder::maybeVisitAtomicFence(Expression*& out, uint8_t code) {
+  if (code != BinaryConsts::AtomicFence) {
+    return false;
+  }
+  auto* curr = allocator.alloc<AtomicFence>();
+  if (debug) {
+    std::cerr << "zz node: AtomicFence" << std::endl;
+  }
+  curr->order = getU32LEB();
+  curr->finalize();
+  out = curr;
+  return true;
+}
+
 bool WasmBinaryBuilder::maybeVisitConst(Expression*& out, uint8_t code) {
   Const* curr;
   if (debug) {
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;
diff --git a/src/wasm/wasm-stack.cpp b/src/wasm/wasm-stack.cpp
index cb60c50f9..faa06330b 100644
--- a/src/wasm/wasm-stack.cpp
+++ b/src/wasm/wasm-stack.cpp
@@ -422,6 +422,11 @@ void BinaryInstWriter::visitAtomicNotify(AtomicNotify* curr) {
   emitMemoryAccess(4, 4, 0);
 }
 
+void BinaryInstWriter::visitAtomicFence(AtomicFence* curr) {
+  o << int8_t(BinaryConsts::AtomicPrefix) << int8_t(BinaryConsts::AtomicFence)
+    << int8_t(curr->order);
+}
+
 void BinaryInstWriter::visitSIMDExtract(SIMDExtract* curr) {
   o << int8_t(BinaryConsts::SIMDPrefix);
   switch (curr->op) {
diff --git a/src/wasm/wasm-validator.cpp b/src/wasm/wasm-validator.cpp
index 339ad6f68..9b1220371 100644
--- a/src/wasm/wasm-validator.cpp
+++ b/src/wasm/wasm-validator.cpp
@@ -270,6 +270,7 @@ public:
   void visitAtomicCmpxchg(AtomicCmpxchg* curr);
   void visitAtomicWait(AtomicWait* curr);
   void visitAtomicNotify(AtomicNotify* curr);
+  void visitAtomicFence(AtomicFence* curr);
   void visitSIMDExtract(SIMDExtract* curr);
   void visitSIMDReplace(SIMDReplace* curr);
   void visitSIMDShuffle(SIMDShuffle* curr);
@@ -917,6 +918,21 @@ void FunctionValidator::visitAtomicNotify(AtomicNotify* curr) {
     "AtomicNotify notifyCount type must be i32");
 }
 
+void FunctionValidator::visitAtomicFence(AtomicFence* curr) {
+  shouldBeTrue(
+    getModule()->memory.exists, curr, "Memory operations require a memory");
+  shouldBeTrue(getModule()->features.hasAtomics(),
+               curr,
+               "Atomic operation (atomics are disabled)");
+  shouldBeFalse(!getModule()->memory.shared,
+                curr,
+                "Atomic operation with non-shared memory");
+  shouldBeTrue(curr->order == 0,
+               curr,
+               "Currently only sequentially consistent atomics are supported, "
+               "so AtomicFence's order should be 0");
+}
+
 void FunctionValidator::visitSIMDExtract(SIMDExtract* curr) {
   shouldBeTrue(
     getModule()->features.hasSIMD(), curr, "SIMD operation (SIMD is disabled)");
diff --git a/src/wasm/wasm.cpp b/src/wasm/wasm.cpp
index f8791286c..b13797c89 100644
--- a/src/wasm/wasm.cpp
+++ b/src/wasm/wasm.cpp
@@ -147,6 +147,8 @@ const char* getExpressionName(Expression* curr) {
       return "atomic_wait";
     case Expression::Id::AtomicNotifyId:
       return "atomic_notify";
+    case Expression::Id::AtomicFenceId:
+      return "atomic_fence";
     case Expression::Id::SIMDExtractId:
       return "simd_extract";
     case Expression::Id::SIMDReplaceId: