Update V8 to r7427: Initial merge by git
As required by WebKit r82507
Change-Id: I7ae83ef3f689356043b4929255b7c1dd31d8c5df
diff --git a/src/api.h b/src/api.h
index d07d75b..6d46713 100644
--- a/src/api.h
+++ b/src/api.h
@@ -122,7 +122,7 @@
template <typename T>
static inline v8::internal::Handle<v8::internal::Object> FromCData(T obj) {
STATIC_ASSERT(sizeof(T) == sizeof(v8::internal::Address));
- return v8::internal::Factory::NewProxy(
+ return FACTORY->NewProxy(
reinterpret_cast<v8::internal::Address>(reinterpret_cast<intptr_t>(obj)));
}
@@ -157,7 +157,6 @@
RegisteredExtension* next_auto_;
ExtensionTraversalState state_;
static RegisteredExtension* first_extension_;
- static RegisteredExtension* first_auto_extension_;
};
@@ -321,16 +320,83 @@
namespace internal {
+// Tracks string usage to help make better decisions when
+// externalizing strings.
+//
+// Implementation note: internally this class only tracks fresh
+// strings and keeps a single use counter for them.
+class StringTracker {
+ public:
+ // Records that the given string's characters were copied to some
+ // external buffer. If this happens often we should honor
+ // externalization requests for the string.
+ void RecordWrite(Handle<String> string) {
+ Address address = reinterpret_cast<Address>(*string);
+ Address top = isolate_->heap()->NewSpaceTop();
+ if (IsFreshString(address, top)) {
+ IncrementUseCount(top);
+ }
+ }
+
+ // Estimates freshness and use frequency of the given string based
+ // on how close it is to the new space top and the recorded usage
+ // history.
+ inline bool IsFreshUnusedString(Handle<String> string) {
+ Address address = reinterpret_cast<Address>(*string);
+ Address top = isolate_->heap()->NewSpaceTop();
+ return IsFreshString(address, top) && IsUseCountLow(top);
+ }
+
+ private:
+ StringTracker() : use_count_(0), last_top_(NULL), isolate_(NULL) { }
+
+ static inline bool IsFreshString(Address string, Address top) {
+ return top - kFreshnessLimit <= string && string <= top;
+ }
+
+ inline bool IsUseCountLow(Address top) {
+ if (last_top_ != top) return true;
+ return use_count_ < kUseLimit;
+ }
+
+ inline void IncrementUseCount(Address top) {
+ if (last_top_ != top) {
+ use_count_ = 0;
+ last_top_ = top;
+ }
+ ++use_count_;
+ }
+
+ // Single use counter shared by all fresh strings.
+ int use_count_;
+
+ // Last new space top when the use count above was valid.
+ Address last_top_;
+
+ Isolate* isolate_;
+
+ // How close to the new space top a fresh string has to be.
+ static const int kFreshnessLimit = 1024;
+
+ // The number of uses required to consider a string useful.
+ static const int kUseLimit = 32;
+
+ friend class Isolate;
+
+ DISALLOW_COPY_AND_ASSIGN(StringTracker);
+};
+
+
// This class is here in order to be able to declare it a friend of
// HandleScope. Moving these methods to be members of HandleScope would be
-// neat in some ways, but it would expose external implementation details in
+// neat in some ways, but it would expose internal implementation details in
// our public header file, which is undesirable.
//
-// There is a singleton instance of this class to hold the per-thread data.
-// For multithreaded V8 programs this data is copied in and out of storage
+// An isolate has a single instance of this class to hold the current thread's
+// data. In multithreaded V8 programs this data is copied in and out of storage
// so that the currently executing thread always has its own copy of this
// data.
-class HandleScopeImplementer {
+ISOLATED_CLASS HandleScopeImplementer {
public:
HandleScopeImplementer()
@@ -341,16 +407,14 @@
ignore_out_of_memory_(false),
call_depth_(0) { }
- static HandleScopeImplementer* instance();
-
// Threading support for handle data.
static int ArchiveSpacePerThread();
- static char* RestoreThread(char* from);
- static char* ArchiveThread(char* to);
- static void FreeThreadResources();
+ char* RestoreThread(char* from);
+ char* ArchiveThread(char* to);
+ void FreeThreadResources();
// Garbage collection support.
- static void Iterate(v8::internal::ObjectVisitor* v);
+ void Iterate(v8::internal::ObjectVisitor* v);
static char* Iterate(v8::internal::ObjectVisitor* v, char* data);