Make internalized string parser in JSON.parse GC-safe

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index 89ac974e89e27b4c2e4c5a0b34ae5153cc3084f6..e2414d290046927d3d3f4a7e13d3b09e0311d5df 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -533,21 +533,17 @@ class OneByteStringKey : public SequentialStringKey<uint8_t> {
 };
 
 
-template<class Char>
-class SubStringKey : public HashTableKey {
+class SeqOneByteSubStringKey : public HashTableKey {
  public:
-  SubStringKey(Handle<String> string, int from, int length)
+  SeqOneByteSubStringKey(Handle<SeqOneByteString> string, int from, int length)
       : string_(string), from_(from), length_(length) {
-    if (string_->IsSlicedString()) {
-      string_ = Handle<String>(Unslice(*string_, &from_));
-    }
-    DCHECK(string_->IsSeqString() || string->IsExternalString());
+    DCHECK(string_->IsSeqOneByteString());
   }
 
   virtual uint32_t Hash() V8_OVERRIDE {
     DCHECK(length_ >= 0);
     DCHECK(from_ + length_ <= string_->length());
-    const Char* chars = GetChars() + from_;
+    const uint8_t* chars = string_->GetChars() + from_;
     hash_field_ = StringHasher::HashSequentialString(
         chars, length_, string_->GetHeap()->HashSeed());
     uint32_t result = hash_field_ >> String::kHashShift;
@@ -563,17 +559,7 @@ class SubStringKey : public HashTableKey {
   virtual Handle<Object> AsHandle(Isolate* isolate) V8_OVERRIDE;
 
  private:
-  const Char* GetChars();
-  String* Unslice(String* string, int* offset) {
-    while (string->IsSlicedString()) {
-      SlicedString* sliced = SlicedString::cast(string);
-      *offset += sliced->offset();
-      string = sliced->parent();
-    }
-    return string;
-  }
-
-  Handle<String> string_;
+  Handle<SeqOneByteString> string_;
   int from_;
   int length_;
   uint32_t hash_field_;