Specialize JSON parser to only check for SequentialAsciiString once.

Review URL: http://codereview.chromium.org/7134010

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@8214 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/SConscript

@@ -85,7 +85,6 @@ SOURCES = {
     inspector.cc
     interpreter-irregexp.cc
     isolate.cc
-    json-parser.cc
     jsregexp.cc
     lithium-allocator.cc
     lithium.cc

src/runtime.cc

@@ -8480,7 +8480,14 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_ParseJson) {
   ASSERT_EQ(1, args.length());
   CONVERT_ARG_CHECKED(String, source, 0);
 
-  Handle<Object> result = JsonParser::Parse(source);
+  source = Handle<String>(source->TryFlattenGetString());
+  // Optimized fast case where we only have ascii characters.
+  Handle<Object> result;
+  if (source->IsSeqAsciiString()) {
+    result = JsonParser<true>::Parse(source);
+  } else {
+    result = JsonParser<false>::Parse(source);
+  }
   if (result.is_null()) {
     // Syntax error or stack overflow in scanner.
     ASSERT(isolate->has_pending_exception());

tools/gyp/v8.gyp

@@ -525,7 +525,6 @@
             '../../src/inspector.h',
             '../../src/interpreter-irregexp.cc',
             '../../src/interpreter-irregexp.h',
-            '../../src/json-parser.cc',
             '../../src/json-parser.h',
             '../../src/jsregexp.cc',
             '../../src/jsregexp.h',