Improve SeqString::Truncate for latest allocated strings.

src/runtime.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 5119 matching lines @@
   if (length == 0) return isolate->heap()->empty_string();
   if (is_one_byte) {
     return isolate->heap()->AllocateRawOneByteString(length);
   } else {
     return isolate->heap()->AllocateRawTwoByteString(length);
   }
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_TruncateString) {
-  NoHandleAllocation ha(isolate);
-  CONVERT_ARG_CHECKED(SeqString, string, 0);
+  HandleScope scope(isolate);
+  CONVERT_ARG_HANDLE_CHECKED(SeqString, string, 0);
   CONVERT_SMI_ARG_CHECKED(new_length, 1);
-  return string->Truncate(new_length);
+  return *SeqString::Truncate(string, new_length);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_URIEscape) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(String, source, 0);
   Handle<String> string = FlattenGetString(source);
   String::FlatContent content = string->GetFlatContent();
   ASSERT(content.IsFlat());
@@ skipping 7832 matching lines @@
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     isolate->counters()->gc_last_resort_from_js()->Increment();
     isolate->heap()->CollectAllGarbage(Heap::kNoGCFlags,
                                        "Runtime::PerformGC");
   }
 }
 
 
 } }  // namespace v8::internal