Introduce a handle zapping setting, and enable it by default for release and debug

The checks are split out from "extra checks" which are too expensive to
turn on by default.

R=danno@chromium.org

Review URL: https://codereview.chromium.org/18316006

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@15548 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

Makefile

@@ -80,6 +80,13 @@ endif
 ifeq ($(extrachecks), off)
   GYPFLAGS += -Dv8_enable_extra_checks=0
 endif
+# handlezapping=on/off
+ifeq ($(handlezapping), on)
+  GYPFLAGS += -Dv8_enable_handle_zapping=1
+endif
+ifeq ($(handlezapping), off)
+  GYPFLAGS += -Dv8_enable_handle_zapping=0
+endif
 # gdbjit=on/off
 ifeq ($(gdbjit), on)
   GYPFLAGS += -Dv8_enable_gdbjit=1

build/common.gypi

@@ -490,6 +490,7 @@
       'Debug': {
         'variables': {
           'v8_enable_extra_checks%': 1,
+          'v8_enable_handle_zapping%': 1,
         },
         'defines': [
           'DEBUG',
@@ -518,6 +519,9 @@
           ['v8_enable_extra_checks==1', {
             'defines': ['ENABLE_EXTRA_CHECKS',],
           }],
+          ['v8_enable_handle_zapping==1', {
+            'defines': ['ENABLE_HANDLE_ZAPPING',],
+          }],
           ['OS=="linux" or OS=="freebsd" or OS=="openbsd" or OS=="netbsd"', {
             'cflags': [ '-Wall', '<(werror)', '-W', '-Wno-unused-parameter',
                         '-Wnon-virtual-dtor', '-Woverloaded-virtual' ],
@@ -550,11 +554,15 @@
       'Release': {
         'variables': {
           'v8_enable_extra_checks%': 0,
+          'v8_enable_handle_zapping%': 1,
         },
         'conditions': [
           ['v8_enable_extra_checks==1', {
             'defines': ['ENABLE_EXTRA_CHECKS',],
           }],
+          ['v8_enable_handle_zapping==1', {
+            'defines': ['ENABLE_HANDLE_ZAPPING',],
+          }],
           ['OS=="linux" or OS=="freebsd" or OS=="openbsd" or OS=="netbsd"', {
             'cflags!': [
               '-O2',

src/api.cc

@@ -7979,7 +7979,7 @@ DeferredHandles::~DeferredHandles() {
   isolate_->UnlinkDeferredHandles(this);
 
   for (int i = 0; i < blocks_.length(); i++) {
-#ifdef ENABLE_EXTRA_CHECKS
+#ifdef ENABLE_HANDLE_ZAPPING
     HandleScope::ZapRange(blocks_[i], &blocks_[i][kHandleBlockSize]);
 #endif
     isolate_->handle_scope_implementer()->ReturnBlock(blocks_[i]);

src/api.h

@@ -665,17 +665,22 @@ void HandleScopeImplementer::DeleteExtensions(internal::Object** prev_limit) {
 #ifdef DEBUG
     // SealHandleScope may make the prev_limit to point inside the block.
     if (block_start <= prev_limit && prev_limit <= block_limit) {
-#ifdef ENABLE_EXTRA_CHECKS
+#ifdef ENABLE_HANDLE_ZAPPING
       internal::HandleScope::ZapRange(prev_limit, block_limit);
 #endif
       break;
     }
 #else
-    if (prev_limit == block_limit) break;
+    if (prev_limit == block_limit) {
+#ifdef ENABLE_HANDLE_ZAPPING
+      internal::HandleScope::ZapRange(prev_limit, block_limit);
+#endif
+      break;
+    }
 #endif
 
     blocks_.RemoveLast();
-#ifdef ENABLE_EXTRA_CHECKS
+#ifdef ENABLE_HANDLE_ZAPPING
     internal::HandleScope::ZapRange(block_start, block_limit);
 #endif
     if (spare_ != NULL) {

src/global-handles.cc

@@ -78,7 +78,7 @@ class GlobalHandles::Node {
                   Internals::kNodeIsPartiallyDependentShift);
   }
 
-#ifdef ENABLE_EXTRA_CHECKS
+#ifdef ENABLE_HANDLE_ZAPPING
   ~Node() {
     // TODO(1428): if it's a weak handle we should have invoked its callback.
     // Zap the values for eager trapping.
@@ -117,7 +117,7 @@ class GlobalHandles::Node {
   void Release() {
     ASSERT(state() != FREE);
     set_state(FREE);
-#ifdef ENABLE_EXTRA_CHECKS
+#ifdef ENABLE_HANDLE_ZAPPING
     // Zap the values for eager trapping.
     object_ = reinterpret_cast<Object*>(kGlobalHandleZapValue);
     class_id_ = v8::HeapProfiler::kPersistentHandleNoClassId;

src/handles-inl.h

@@ -134,7 +134,7 @@ void HandleScope::CloseScope(Isolate* isolate,
     DeleteExtensions(isolate);
   }
 
-#ifdef ENABLE_EXTRA_CHECKS
+#ifdef ENABLE_HANDLE_ZAPPING
   ZapRange(prev_next, prev_limit);
 #endif
 }

src/handles.cc

@@ -101,7 +101,7 @@ void HandleScope::DeleteExtensions(Isolate* isolate) {
 }
 
 
-#ifdef ENABLE_EXTRA_CHECKS
+#ifdef ENABLE_HANDLE_ZAPPING
 void HandleScope::ZapRange(Object** start, Object** end) {
   ASSERT(end - start <= kHandleBlockSize);
   for (Object** p = start; p != end; p++) {
@@ -554,7 +554,7 @@ v8::Handle<v8::Array> GetKeysForNamedInterceptor(Handle<JSReceiver> receiver,
     LOG(isolate, ApiObjectAccess("interceptor-named-enum", *object));
     result = args.Call(enum_fun);
   }
-#if ENABLE_EXTRA_CHECKS
+#if ENABLE_HANDLE_ZAPPING
   CHECK(result.IsEmpty() || v8::Utils::OpenHandle(*result)->IsJSObject());
 #endif
   return v8::Local<v8::Array>::New(reinterpret_cast<v8::Isolate*>(isolate),
@@ -575,7 +575,7 @@ v8::Handle<v8::Array> GetKeysForIndexedInterceptor(Handle<JSReceiver> receiver,
         v8::ToCData<v8::IndexedPropertyEnumerator>(interceptor->enumerator());
     LOG(isolate, ApiObjectAccess("interceptor-indexed-enum", *object));
     result = args.Call(enum_fun);
-#if ENABLE_EXTRA_CHECKS
+#if ENABLE_HANDLE_ZAPPING
     CHECK(result.IsEmpty() || v8::Utils::OpenHandle(*result)->IsJSObject());
 #endif
   }

src/handles.h

@@ -177,7 +177,7 @@ class HandleScope {
   // Extend the handle scope making room for more handles.
   static internal::Object** Extend(Isolate* isolate);
 
-#ifdef ENABLE_EXTRA_CHECKS
+#ifdef ENABLE_HANDLE_ZAPPING
   // Zaps the handles in the half-open interval [start, end).
   static void ZapRange(Object** start, Object** end);
 #endif