1 files changed, 64 insertions, 0 deletions

diff --git a/src/wasm/wasm-binary.cpp b/src/wasm/wasm-binary.cpp
index 69d3ecdbb..efbd82e8b 100644
--- a/src/wasm/wasm-binary.cpp
+++ b/src/wasm/wasm-binary.cpp
@@ -877,6 +877,37 @@ void WasmBinaryWriter::visitAtomicRMW(AtomicRMW *curr) {
   emitMemoryAccess(curr->bytes, curr->bytes, curr->offset);
 }
 
+void WasmBinaryWriter::visitAtomicCmpxchg(AtomicCmpxchg *curr) {
+  if (debug) std::cerr << "zz node: AtomicCmpxchg" << std::endl;
+  recurse(curr->ptr);
+  recurse(curr->expected);
+  recurse(curr->replacement);
+
+  o << int8_t(BinaryConsts::AtomicPrefix);
+  switch (curr->type) {
+    case i32:
+      switch (curr->bytes) {
+        case 1: o << int8_t(BinaryConsts::I32AtomicCmpxchg8U); break;
+        case 2: o << int8_t(BinaryConsts::I32AtomicCmpxchg16U); break;
+        case 4: o << int8_t(BinaryConsts::I32AtomicCmpxchg); break;
+        default: WASM_UNREACHABLE();
+      }
+      break;
+    case i64:
+      switch (curr->bytes) {
+        case 1: o << int8_t(BinaryConsts::I64AtomicCmpxchg8U); break;
+        case 2: o << int8_t(BinaryConsts::I64AtomicCmpxchg16U); break;
+        case 4: o << int8_t(BinaryConsts::I64AtomicCmpxchg32U); break;
+        case 8: o << int8_t(BinaryConsts::I64AtomicCmpxchg); break;
+        default: WASM_UNREACHABLE();
+      }
+      break;
+    default: WASM_UNREACHABLE();
+  }
+  emitMemoryAccess(curr->bytes, curr->bytes, curr->offset);
+}
+
+
 void WasmBinaryWriter::visitConst(Const *curr) {
   if (debug) std::cerr << "zz node: Const" << curr << " : " << curr->type << std::endl;
   switch (curr->type) {
@@ -1980,6 +2011,7 @@ BinaryConsts::ASTNodes WasmBinaryBuilder::readExpression(Expression*& curr) {
       if (maybeVisitLoad(curr, code, /*isAtomic=*/true)) break;
       if (maybeVisitStore(curr, code, /*isAtomic=*/true)) break;
       if (maybeVisitAtomicRMW(curr, code)) break;
+      if (maybeVisitAtomicCmpxchg(curr, code)) break;
       throw ParseException("invalid code after atomic prefix: " + std::to_string(code));
     }
     default: {
@@ -2372,6 +2404,38 @@ bool WasmBinaryBuilder::maybeVisitAtomicRMW(Expression*& out, uint8_t code) {
   return true;
 }
 
+bool WasmBinaryBuilder::maybeVisitAtomicCmpxchg(Expression*& out, uint8_t code) {
+  if (code < BinaryConsts::AtomicCmpxchgOps_Begin || code > BinaryConsts::AtomicCmpxchgOps_End) return false;
+  auto* curr = allocator.alloc<AtomicCmpxchg>();
+
+  // Set curr to the given type and size.
+#define SET(optype, size)         \
+  curr->type = optype;            \
+  curr->bytes = size
+
+  switch (code) {
+    case BinaryConsts::I32AtomicCmpxchg: SET(i32, 4); break;
+    case BinaryConsts::I64AtomicCmpxchg: SET(i64, 8); break;
+    case BinaryConsts::I32AtomicCmpxchg8U: SET(i32, 1); break;
+    case BinaryConsts::I32AtomicCmpxchg16U: SET(i32, 2); break;
+    case BinaryConsts::I64AtomicCmpxchg8U: SET(i64, 1); break;
+    case BinaryConsts::I64AtomicCmpxchg16U: SET(i64, 2); break;
+    case BinaryConsts::I64AtomicCmpxchg32U: SET(i64, 4); break;
+    default: WASM_UNREACHABLE();
+  }
+
+  if (debug) std::cerr << "zz node: AtomicCmpxchg" << std::endl;
+  Address readAlign;
+  readMemoryAccess(readAlign, curr->bytes, curr->offset);
+  if (readAlign != curr->bytes) throw ParseException("Align of AtomicCpxchg must match size");
+  curr->replacement = popNonVoidExpression();
+  curr->expected = popNonVoidExpression();
+  curr->ptr = popNonVoidExpression();
+  curr->finalize();
+  out = curr;
+  return true;
+}
+
 bool WasmBinaryBuilder::maybeVisitConst(Expression*& out, uint8_t code) {
   Const* curr;
   if (debug) std::cerr << "zz node: Const, code " << code << std::endl;