Fix a segment-fault caused by Value::IntegerValue

src/api.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/api.h"
 
 #include <string.h>  // For memcpy, strlen.
 #ifdef V8_USE_ADDRESS_SANITIZER
 #include <sanitizer/asan_interface.h>
 #endif  // V8_USE_ADDRESS_SANITIZER
@@ skipping 3246 matching lines @@
   return NumberValue(ContextFromHeapObject(obj))
       .FromMaybe(std::numeric_limits<double>::quiet_NaN());
 }
 
 
 Maybe<int64_t> Value::IntegerValue(Local<Context> context) const {
   auto obj = Utils::OpenHandle(this);
   i::Handle<i::Object> num;
   if (obj->IsNumber()) {
     num = obj;
+    return Just(num->IsSmi() ? static_cast<int64_t>(i::Smi::cast(*num)->value())
+                             : static_cast<int64_t>(num->Number()));
   } else {
     PREPARE_FOR_EXECUTION_PRIMITIVE(context, "IntegerValue", int64_t);
     has_pending_exception =

[jochen (gone - plz use gerrit), 2015/09/09 14:16:59]

can you pull the if() case in here instead of duplicating the returns?

something like

PREPARE_FOR...
if (obj->isNumber())
 num = obj;
else {
 has_pending = ...

[noordhuis, 2015/09/09 23:35:56]

That pessimizes the common case when the input is a SMI or double. 
PREPARE_FOR_EXECUTION_PRIMITIVE mutates a couple of per-isolate data structures
and is fairly heavy-weight.

         !i::Execution::ToInteger(isolate, obj).ToHandle(&num);
     RETURN_ON_FAILED_EXECUTION_PRIMITIVE(int64_t);
+    return Just(num->IsSmi() ? static_cast<int64_t>(i::Smi::cast(*num)->value())
+                             : static_cast<int64_t>(num->Number()));
   }
-  return Just(num->IsSmi() ? static_cast<int64_t>(i::Smi::cast(*num)->value())
-                           : static_cast<int64_t>(num->Number()));
 }
 
 
 int64_t Value::IntegerValue() const {
   auto obj = Utils::OpenHandle(this);
   if (obj->IsNumber()) {
     if (obj->IsSmi()) {
       return i::Smi::cast(*obj)->value();
     } else {
       return static_cast<int64_t>(obj->Number());
@@ skipping 5118 matching lines @@
   Address callback_address =
       reinterpret_cast<Address>(reinterpret_cast<intptr_t>(callback));
   VMState<EXTERNAL> state(isolate);
   ExternalCallbackScope call_scope(isolate, callback_address);
   callback(info);
 }
 
 
 }  // namespace internal
 }  // namespace v8