[debugging] Add %Verify() helper and check verify a HeapObject has a Map.

R=jkummerow@chromium.org

Review-Url: https://codereview.chromium.org/2625053006
Cr-Commit-Position: refs/heads/master@{#42322}

src/objects-debug.cc

@@ -44,6 +44,8 @@ void Smi::SmiVerify() {
 
 
 void HeapObject::HeapObjectVerify() {
+  VerifyHeapPointer(map());
+  CHECK(map()->IsMap());
   InstanceType instance_type = map()->instance_type();
 
   if (instance_type < FIRST_NONSTRING_TYPE) {

src/runtime/runtime-test.cc

@@ -828,5 +828,22 @@ RUNTIME_FUNCTION(Runtime_ValidateWasmOrphanedInstance) {
   return isolate->heap()->ToBoolean(true);
 }
 
+RUNTIME_FUNCTION(Runtime_Verify) {
+  HandleScope shs(isolate);
+  DCHECK_EQ(1, args.length());
+  CONVERT_ARG_HANDLE_CHECKED(Object, object, 0);
+#ifdef VERIFY_HEAP
+  object->ObjectVerify();
+#else
+  CHECK(object->IsObject());
+  if (object->IsHeapObject()) {
+    CHECK(HeapObject::cast(*object)->map()->IsMap());
+  } else {
+    CHECK(object->IsSmi());
+  }
+#endif
+  return isolate->heap()->ToBoolean(true);
+}
+
 }  // namespace internal
 }  // namespace v8

src/runtime/runtime.h

@@ -910,7 +910,8 @@ namespace internal {
   F(IsWasmCode, 1, 1)                         \
   F(ValidateWasmInstancesChain, 2, 1)         \
   F(ValidateWasmModuleState, 1, 1)            \
-  F(ValidateWasmOrphanedInstance, 1, 1)
+  F(ValidateWasmOrphanedInstance, 1, 1)       \
+  F(Verify, 1, 1)
 
 #define FOR_EACH_INTRINSIC_TYPEDARRAY(F)     \
   F(ArrayBufferGetByteLength, 1, 1)          \