deps: backport 1f8555 from v8's upstream

Original commit message:

    api: introduce SealHandleScope

    When debugging Handle leaks in io.js we found it very convenient to be
    able to Seal some specific (root in our case) scope to prevent Handle
    allocations in it, and easily find leakage.

    R=yangguo
    BUG=

    Review URL: https://codereview.chromium.org/1079713002

    Cr-Commit-Position: refs/heads/master@{#27766}

Should help us identify and fix Handle leaks in core and user-space code.

NOTE: Works only in Debug build now, but is still better than nothing.

PR-URL: https://github.com/iojs/io.js/pull/1395
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>

diff --git a/deps/v8/include/v8.h b/deps/v8/include/v8.h
index 32730eb..218e919 100644 (file)
--- a/deps/v8/include/v8.h
+++ b/deps/v8/include/v8.h
@@ -1006,6 +1006,24 @@ class ScriptOrigin {
   Handle<Integer> script_id_;
 };
 
+class V8_EXPORT SealHandleScope {
+ public:
+  SealHandleScope(Isolate* isolate);
+  ~SealHandleScope();
+
+ private:
+  // Make it hard to create heap-allocated or illegal handle scopes by
+  // disallowing certain operations.
+  SealHandleScope(const SealHandleScope&);
+  void operator=(const SealHandleScope&);
+  void* operator new(size_t size);
+  void operator delete(void*, size_t);
+
+  internal::Isolate* isolate_;
+  int prev_level_;
+  internal::Object** prev_limit_;
+};
+
 
 /**
  * A compiled JavaScript script, not yet tied to a Context.

diff --git a/deps/v8/src/api.cc b/deps/v8/src/api.cc
index 88d3c88..c3f8453 100644 (file)
--- a/deps/v8/src/api.cc
+++ b/deps/v8/src/api.cc
@@ -515,6 +515,27 @@ i::Object** EscapableHandleScope::Escape(i::Object** escape_value) {
 }
 
 
+SealHandleScope::SealHandleScope(Isolate* isolate) {
+  i::Isolate* internal_isolate = reinterpret_cast<i::Isolate*>(isolate);
+
+  isolate_ = internal_isolate;
+  i::HandleScopeData* current = internal_isolate->handle_scope_data();
+  prev_limit_ = current->limit;
+  current->limit = current->next;
+  prev_level_ = current->level;
+  current->level = 0;
+}
+
+
+SealHandleScope::~SealHandleScope() {
+  i::HandleScopeData* current = isolate_->handle_scope_data();
+  DCHECK_EQ(0, current->level);
+  current->level = prev_level_;
+  DCHECK_EQ(current->next, current->limit);
+  current->limit = prev_limit_;
+}
+
+
 void Context::Enter() {
   i::Handle<i::Context> env = Utils::OpenHandle(this);
   i::Isolate* isolate = env->GetIsolate();

diff --git a/deps/v8/src/api.h b/deps/v8/src/api.h
index 1d2a8c8..62f9f1e 100644 (file)
--- a/deps/v8/src/api.h
+++ b/deps/v8/src/api.h
@@ -650,7 +650,7 @@ void HandleScopeImplementer::DeleteExtensions(internal::Object** prev_limit) {
   while (!blocks_.is_empty()) {
     internal::Object** block_start = blocks_.last();
     internal::Object** block_limit = block_start + kHandleBlockSize;
-#ifdef DEBUG
+
     // SealHandleScope may make the prev_limit to point inside the block.
     if (block_start <= prev_limit && prev_limit <= block_limit) {
 #ifdef ENABLE_HANDLE_ZAPPING
@@ -658,9 +658,6 @@ void HandleScopeImplementer::DeleteExtensions(internal::Object** prev_limit) {
 #endif
       break;
     }
-#else
-    if (prev_limit == block_limit) break;
-#endif
 
     blocks_.RemoveLast();
 #ifdef ENABLE_HANDLE_ZAPPING

diff --git a/deps/v8/test/cctest/cctest.status b/deps/v8/test/cctest/cctest.status
index cc5414d..95fb839 100644 (file)
--- a/deps/v8/test/cctest/cctest.status
+++ b/deps/v8/test/cctest/cctest.status
@@ -40,6 +40,7 @@
   # they don't fail then test.py has failed.
   'test-serialize/TestThatAlwaysFails': [FAIL],
   'test-serialize/DependentTestThatAlwaysFails': [FAIL],
+  'test-api/SealHandleScope': [FAIL],
 
   # This test always fails.  It tests that LiveEdit causes abort when turned off.
   'test-debug/LiveEditDisabled': [FAIL],

diff --git a/deps/v8/test/cctest/test-api.cc b/deps/v8/test/cctest/test-api.cc
index 06cf553..17de186 100644 (file)
--- a/deps/v8/test/cctest/test-api.cc
+++ b/deps/v8/test/cctest/test-api.cc
@@ -21895,6 +21895,38 @@ void CallCompletedCallbackException() {
 }
 
 
+TEST(SealHandleScope) {
+  v8::Isolate* isolate = CcTest::isolate();
+  v8::HandleScope handle_scope(isolate);
+  LocalContext env;
+
+  v8::SealHandleScope seal(isolate);
+
+  // Should fail
+  v8::Local<v8::Object> obj = v8::Object::New(isolate);
+
+  USE(obj);
+}
+
+
+TEST(SealHandleScopeNested) {
+  v8::Isolate* isolate = CcTest::isolate();
+  v8::HandleScope handle_scope(isolate);
+  LocalContext env;
+
+  v8::SealHandleScope seal(isolate);
+
+  {
+    v8::HandleScope handle_scope(isolate);
+
+    // Should work
+    v8::Local<v8::Object> obj = v8::Object::New(isolate);
+
+    USE(obj);
+  }
+}
+
+
 TEST(CallCompletedCallbackOneException) {
   LocalContext env;
   v8::HandleScope scope(env->GetIsolate());