Retire StringTracker.

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 5114 matching lines @@
 static inline int WriteHelper(const String* string,
                               CharType* buffer,
                               int start,
                               int length,
                               int options) {
   i::Isolate* isolate = Utils::OpenHandle(string)->GetIsolate();
   LOG_API(isolate, "String::Write");
   ENTER_V8(isolate);
   DCHECK(start >= 0 && length >= -1);
   i::Handle<i::String> str = Utils::OpenHandle(string);
-  isolate->string_tracker()->RecordWrite(str);
   if (options & String::HINT_MANY_WRITES_EXPECTED) {
     // Flatten the string for efficiency.  This applies whether we are
     // using StringCharacterStream or Get(i) to access the characters.
     str = i::String::Flatten(str);
   }
   int end = start + length;
   if ((length == -1) || (length > str->length() - start) )
     end = str->length();
   if (end < 0) return 0;
   i::String::WriteToFlat(*str, buffer, start, end);
@@ skipping 685 matching lines @@
 }
 
 
 bool v8::String::MakeExternal(v8::String::ExternalStringResource* resource) {
   i::Handle<i::String> obj = Utils::OpenHandle(this);
   i::Isolate* isolate = obj->GetIsolate();
   if (i::StringShape(*obj).IsExternal()) {
     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());
 
   bool result = obj->MakeExternal(resource);
   // Assert that if CanMakeExternal(), then externalizing actually succeeds.
   DCHECK(!CanMakeExternal() || result);
   if (result) {
     DCHECK(obj->IsExternalString());
     isolate->heap()->external_string_table()->AddString(*obj);
   }
   return result;
 }
 
 
 bool v8::String::MakeExternal(
     v8::String::ExternalOneByteStringResource* resource) {
   i::Handle<i::String> obj = Utils::OpenHandle(this);
   i::Isolate* isolate = obj->GetIsolate();
   if (i::StringShape(*obj).IsExternal()) {
     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());
 
   bool result = obj->MakeExternal(resource);
   // Assert that if CanMakeExternal(), then externalizing actually succeeds.
   DCHECK(!CanMakeExternal() || result);
   if (result) {
     DCHECK(obj->IsExternalString());
     isolate->heap()->external_string_table()->AddString(*obj);
   }
   return result;
 }
 
 
 bool v8::String::CanMakeExternal() {
   i::Handle<i::String> obj = Utils::OpenHandle(this);
   i::Isolate* isolate = obj->GetIsolate();
 
-  if (isolate->string_tracker()->IsFreshUnusedString(obj)) return false;
+  // Old space strings should be externalized.
+  if (!isolate->heap()->new_space()->Contains(*obj)) return true;
   int size = obj->Size();  // Byte size of the original string.
-  if (size < i::ExternalString::kShortSize) return false;
+  if (size <= i::ExternalString::kShortSize) return false;
   i::StringShape shape(*obj);
   return !shape.IsExternal();
 }
 
 
 Isolate* v8::Object::GetIsolate() {
   i::Isolate* i_isolate = Utils::OpenHandle(this)->GetIsolate();
   return reinterpret_cast<Isolate*>(i_isolate);
 }
 
@@ skipping 2499 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