Check that ExternalString objects get aligned resources.

src/api.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 762 matching lines @@
   isolate->set_context_exit_happened(true);
 }
 
 
 static void* DecodeSmiToAligned(i::Object* value, const char* location) {
   ApiCheck(value->IsSmi(), location, "Not a Smi");
   return reinterpret_cast<void*>(value);
 }
 
 
-static i::Smi* EncodeAlignedAsSmi(void* value, const char* location) {
-  i::Smi* smi = reinterpret_cast<i::Smi*>(value);
+static i::Smi* EncodeAlignedAsSmi(const void* value, const char* location) {
+  i::Smi* smi = const_cast<i::Smi*>(reinterpret_cast<const i::Smi*>(value));
   ApiCheck(smi->IsSmi(), location, "Pointer is not aligned");
   return smi;
 }
 
 
 static i::Handle<i::FixedArray> EmbedderDataFor(Context* context,
                                                 int index,
                                                 bool can_grow,
                                                 const char* location) {
   i::Handle<i::Context> env = Utils::OpenHandle(context);
@@ skipping 5136 matching lines @@
 }
 
 
 Local<String> v8::String::NewExternal(
       v8::String::ExternalStringResource* resource) {
   i::Isolate* isolate = i::Isolate::Current();
   EnsureInitializedForIsolate(isolate, "v8::String::NewExternal()");
   LOG_API(isolate, "String::NewExternal");
   ENTER_V8(isolate);
   CHECK(resource && resource->data());
+  // Resource pointers need to look like Smis since ExternalString objects
+  // are sometimes put into old pointer space (see i::String::MakeExternal).
+  CHECK(EncodeAlignedAsSmi(resource, "v8::String::NewExternal()"));
+  CHECK(EncodeAlignedAsSmi(resource->data(), "v8::String::NewExternal()"));
   i::Handle<i::String> result = NewExternalStringHandle(isolate, resource);
   isolate->heap()->external_string_table()->AddString(*result);
   return Utils::ToLocal(result);
 }
 
 
 bool v8::String::MakeExternal(v8::String::ExternalStringResource* resource) {
   i::Handle<i::String> obj = Utils::OpenHandle(this);
   i::Isolate* isolate = obj->GetIsolate();
   if (IsDeadCheck(isolate, "v8::String::MakeExternal()")) return false;
   if (i::StringShape(*obj).IsExternalTwoByte()) {
     return false;  // Already an external string.
   }
   ENTER_V8(isolate);
   if (isolate->string_tracker()->IsFreshUnusedString(obj)) {
     return false;
   }
   if (isolate->heap()->IsInGCPostProcessing()) {
     return false;
   }
   CHECK(resource && resource->data());
+  // Resource pointers need to look like Smis since ExternalString objects
+  // are sometimes put into old pointer space (see i::String::MakeExternal).
+  CHECK(EncodeAlignedAsSmi(resource, "v8::String::MakeExternal()"));
+  CHECK(EncodeAlignedAsSmi(resource->data(), "v8::String::MakeExternal()"));
   bool result = obj->MakeExternal(resource);
   if (result && !obj->IsInternalizedString()) {
     isolate->heap()->external_string_table()->AddString(*obj);
   }
   return result;
 }
 
 
 Local<String> v8::String::NewExternal(
       v8::String::ExternalAsciiStringResource* resource) {
   i::Isolate* isolate = i::Isolate::Current();
   EnsureInitializedForIsolate(isolate, "v8::String::NewExternal()");
   LOG_API(isolate, "String::NewExternal");
   ENTER_V8(isolate);
   CHECK(resource && resource->data());
+  // Resource pointers need to look like Smis since ExternalString objects
+  // are sometimes put into old pointer space (see i::String::MakeExternal).
+  CHECK(EncodeAlignedAsSmi(resource, "v8::String::NewExternal()"));
+  CHECK(EncodeAlignedAsSmi(resource->data(), "v8::String::NewExternal()"));
   i::Handle<i::String> result = NewExternalAsciiStringHandle(isolate, resource);
   isolate->heap()->external_string_table()->AddString(*result);
   return Utils::ToLocal(result);
 }
 
 
 bool v8::String::MakeExternal(
     v8::String::ExternalAsciiStringResource* resource) {
   i::Handle<i::String> obj = Utils::OpenHandle(this);
   i::Isolate* isolate = obj->GetIsolate();
   if (IsDeadCheck(isolate, "v8::String::MakeExternal()")) return false;
   if (i::StringShape(*obj).IsExternalTwoByte()) {
     return false;  // Already an external string.
   }
   ENTER_V8(isolate);
   if (isolate->string_tracker()->IsFreshUnusedString(obj)) {
     return false;
   }
   if (isolate->heap()->IsInGCPostProcessing()) {
     return false;
   }
   CHECK(resource && resource->data());
+  // Resource pointers need to look like Smis since ExternalString objects
+  // are sometimes put into old pointer space (see i::String::MakeExternal).
+  CHECK(EncodeAlignedAsSmi(resource, "v8::String::MakeExternal()"));
+  CHECK(EncodeAlignedAsSmi(resource->data(), "v8::String::MakeExternal()"));
   bool result = obj->MakeExternal(resource);
   if (result && !obj->IsInternalizedString()) {
     isolate->heap()->external_string_table()->AddString(*obj);
   }
   return result;
 }
 
 
 bool v8::String::CanMakeExternal() {
   if (!internal::FLAG_clever_optimizations) return false;
@@ skipping 2044 matching lines @@
   Isolate* isolate = reinterpret_cast<Isolate*>(info.GetIsolate());
   Address callback_address =
       reinterpret_cast<Address>(reinterpret_cast<intptr_t>(callback));
   VMState<EXTERNAL> state(isolate);
   ExternalCallbackScope call_scope(isolate, callback_address);
   return callback(info);
 }
 
 
 } }  // namespace v8::internal