fix validation of memBytes, if the load type is unreachable, we can't and shouldn't try to validate

Author: kripken

src/wasm-validator.h

@@ -217,7 +217,7 @@ struct WasmValidator : public PostWalker<WasmValidator> {
 
   void validateAlignment(size_t align, WasmType type, Index bytes, bool isAtomic,
                          Expression* curr);
-  void validateMemBytes(uint8_t bytes, WasmType ty, Expression* curr);
+  void validateMemBytes(uint8_t bytes, WasmType type, Expression* curr);
   void validateBinaryenIR(Module& wasm);
 };
 

src/wasm/wasm-validator.cpp

@@ -237,14 +237,17 @@ void WasmValidator::visitAtomicRMW(AtomicRMW* curr) {
 void WasmValidator::visitAtomicCmpxchg(AtomicCmpxchg* curr) {
   validateMemBytes(curr->bytes, curr->type, curr);
 }
-void WasmValidator::validateMemBytes(uint8_t bytes, WasmType ty, Expression* curr) {
+void WasmValidator::validateMemBytes(uint8_t bytes, WasmType type, Expression* curr) {
+  if (type == unreachable) {
+    return; // nothing to validate in this case
+  }
   switch (bytes) {
     case 1:
     case 2:
     case 4:
       break;
     case 8: {
-      shouldBeEqual(getWasmTypeSize(ty), 8U, curr, "8-byte mem operations are only allowed with 8-byte wasm types");
+      shouldBeEqual(getWasmTypeSize(type), 8U, curr, "8-byte mem operations are only allowed with 8-byte wasm types");
       break;
     }
     default: fail("Memory operations must be 1,2,4, or 8 bytes", curr);