Separate JSON parsing from the JavaScript parser.

Switch JSON parsing to creating the value directly instead of createing
code to create the value.

Review URL: http://codereview.chromium.org/4135004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5715 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/compiler.cc

@@ -152,10 +152,8 @@ static Handle<SharedFunctionInfo> MakeFunctionInfo(CompilationInfo* info) {
   script->set_context_data((*i::Top::global_context())->data());
 
 #ifdef ENABLE_DEBUGGER_SUPPORT
-  if (info->is_eval() || info->is_json()) {
-    Script::CompilationType compilation_type = info->is_json()
-        ? Script::COMPILATION_TYPE_JSON
-        : Script::COMPILATION_TYPE_EVAL;
+  if (info->is_eval()) {
+    Script::CompilationType compilation_type = Script::COMPILATION_TYPE_EVAL;
     script->set_compilation_type(Smi::FromInt(compilation_type));
     // For eval scripts add information on the function from which eval was
     // called.
@@ -323,13 +321,7 @@ Handle<SharedFunctionInfo> Compiler::Compile(Handle<String> source,
 
 Handle<SharedFunctionInfo> Compiler::CompileEval(Handle<String> source,
                                                  Handle<Context> context,
-                                                 bool is_global,
-                                                 ValidationState validate) {
-  // Note that if validation is required then no path through this function
-  // is allowed to return a value without validating that the input is legal
-  // json.
-  bool is_json = (validate == VALIDATE_JSON);
-
+                                                 bool is_global) {
   int source_length = source->length();
   Counters::total_eval_size.Increment(source_length);
   Counters::total_compile_size.Increment(source_length);
@@ -338,13 +330,9 @@ Handle<SharedFunctionInfo> Compiler::CompileEval(Handle<String> source,
   VMState state(COMPILER);
 
   // Do a lookup in the compilation cache; if the entry is not there, invoke
-  // the compiler and add the result to the cache.  If we're evaluating json
-  // we bypass the cache since we can't be sure a potential value in the
-  // cache has been validated.
+  // the compiler and add the result to the cache.
   Handle<SharedFunctionInfo> result;
-  if (!is_json) {
-    result = CompilationCache::LookupEval(source, context, is_global);
-  }
+  result = CompilationCache::LookupEval(source, context, is_global);
 
   if (result.is_null()) {
     // Create a script object describing the script to be compiled.
@@ -352,12 +340,9 @@ Handle<SharedFunctionInfo> Compiler::CompileEval(Handle<String> source,
     CompilationInfo info(script);
     info.MarkAsEval();
     if (is_global) info.MarkAsGlobal();
-    if (is_json) info.MarkAsJson();
     info.SetCallingContext(context);
     result = MakeFunctionInfo(&info);
-    if (!result.is_null() && !is_json) {
-      // For json it's unlikely that we'll ever see exactly the same string
-      // again so we don't use the compilation cache.
+    if (!result.is_null()) {
       CompilationCache::PutEval(source, context, is_global, result);
     }
   }

src/compiler.h

@@ -49,7 +49,6 @@ class CompilationInfo BASE_EMBEDDED {
   bool is_lazy() const { return (flags_ & IsLazy::mask()) != 0; }
   bool is_eval() const { return (flags_ & IsEval::mask()) != 0; }
   bool is_global() const { return (flags_ & IsGlobal::mask()) != 0; }
-  bool is_json() const { return (flags_ & IsJson::mask()) != 0; }
   bool is_in_loop() const { return (flags_ & IsInLoop::mask()) != 0; }
   FunctionLiteral* function() const { return function_; }
   Scope* scope() const { return scope_; }
@@ -69,10 +68,6 @@ class CompilationInfo BASE_EMBEDDED {
     ASSERT(!is_lazy());
     flags_ |= IsGlobal::encode(true);
   }
-  void MarkAsJson() {
-    ASSERT(!is_lazy());
-    flags_ |= IsJson::encode(true);
-  }
   void MarkAsInLoop() {
     ASSERT(is_lazy());
     flags_ |= IsInLoop::encode(true);
@@ -108,16 +103,15 @@ class CompilationInfo BASE_EMBEDDED {
   // Flags that can be set for eager compilation.
   class IsEval:   public BitField<bool, 1, 1> {};
   class IsGlobal: public BitField<bool, 2, 1> {};
-  class IsJson:   public BitField<bool, 3, 1> {};
   // Flags that can be set for lazy compilation.
-  class IsInLoop: public BitField<bool, 4, 1> {};
+  class IsInLoop: public BitField<bool, 3, 1> {};
 
   unsigned flags_;
 
   // Fields filled in by the compilation pipeline.
   // AST filled in by the parser.
   FunctionLiteral* function_;
-  // The scope of the function literal as a convenience.  Set to indidicate
+  // The scope of the function literal as a convenience.  Set to indicate
   // that scopes have been analyzed.
   Scope* scope_;
   // The compiled code.
@@ -153,8 +147,6 @@ class CompilationInfo BASE_EMBEDDED {
 
 class Compiler : public AllStatic {
  public:
-  enum ValidationState { DONT_VALIDATE_JSON, VALIDATE_JSON };
-
   // All routines return a JSFunction.
   // If an error occurs an exception is raised and
   // the return handle contains NULL.
@@ -172,8 +164,7 @@ class Compiler : public AllStatic {
   // Compile a String source within a context for Eval.
   static Handle<SharedFunctionInfo> CompileEval(Handle<String> source,
                                                 Handle<Context> context,
-                                                bool is_global,
-                                                ValidationState validation);
+                                                bool is_global);
 
   // Compile from function info (used for lazy compilation). Returns true on
   // success and false if the compilation resulted in a stack overflow.

src/debug-debugger.js

@@ -1301,7 +1301,7 @@ DebugCommandProcessor.prototype.processDebugJSONRequest = function(json_request)
   try {
     try {
       // Convert the JSON string to an object.
-      request = %CompileString('(' + json_request + ')', false)();
+      request = %CompileString('(' + json_request + ')')();
 
       // Create an initial response.
       response = this.createResponse(request);

src/json.js

@@ -29,8 +29,7 @@ var $JSON = global.JSON;
 
 function ParseJSONUnfiltered(text) {
   var s = $String(text);
-  var f = %CompileString(s, true);
-  return f();
+  return %ParseJson(s);
 }
 
 function Revive(holder, name, reviver) {

src/objects.h

@@ -3409,8 +3409,7 @@ class Script: public Struct {
   // Script compilation types.
   enum CompilationType {
     COMPILATION_TYPE_HOST = 0,
-    COMPILATION_TYPE_EVAL = 1,
-    COMPILATION_TYPE_JSON = 2
+    COMPILATION_TYPE_EVAL = 1
   };
 
   // [source]: the script source.

src/parser.h

@@ -218,7 +218,6 @@ class Parser {
   FunctionLiteral* ParseProgram(Handle<String> source,
                                 bool in_global_context);
   FunctionLiteral* ParseLazy(Handle<SharedFunctionInfo> info);
-  FunctionLiteral* ParseJson(Handle<String> source);
 
   // The minimum number of contiguous assignment that will
   // be treated as an initialization block. Benchmarks show that
@@ -411,29 +410,6 @@ class Parser {
                             Handle<String> type,
                             Vector< Handle<Object> > arguments);
 
-  // JSON is a subset of JavaScript, as specified in, e.g., the ECMAScript 5
-  // specification section 15.12.1 (and appendix A.8).
-  // The grammar is given section 15.12.1.2 (and appendix A.8.2).
-
-  // Parse JSON input as a single JSON value.
-  Expression* ParseJson(bool* ok);
-
-  // Parse a single JSON value from input (grammar production JSONValue).
-  // A JSON value is either a (double-quoted) string literal, a number literal,
-  // one of "true", "false", or "null", or an object or array literal.
-  Expression* ParseJsonValue(bool* ok);
-  // Parse a JSON object literal (grammar production JSONObject).
-  // An object literal is a squiggly-braced and comma separated sequence
-  // (possibly empty) of key/value pairs, where the key is a JSON string
-  // literal, the value is a JSON value, and the two are spearated by a colon.
-  // A JavaScript object also allows numbers and identifiers as keys.
-  Expression* ParseJsonObject(bool* ok);
-  // Parses a JSON array literal (grammar production JSONArray). An array
-  // literal is a square-bracketed and comma separated sequence (possibly empty)
-  // of JSON values.
-  // A JavaScript array allows leaving out values from the sequence.
-  Expression* ParseJsonArray(bool* ok);
-
   friend class Target;
   friend class TargetScope;
   friend class LexicalScope;
@@ -472,6 +448,49 @@ class CompileTimeValue: public AllStatic {
 };
 
 
+// JSON is a subset of JavaScript, as specified in, e.g., the ECMAScript 5
+// specification section 15.12.1 (and appendix A.8).
+// The grammar is given section 15.12.1.2 (and appendix A.8.2).
+class JsonParser BASE_EMBEDDED {
+ public:
+  // Parse JSON input as a single JSON value.
+  // Returns null handle and sets exception if parsing failed.
+  static Handle<Object> Parse(Handle<String> source) {
+    return JsonParser().ParseJson(source);
+  }
+
+ private:
+  JsonParser() { }
+  ~JsonParser() { }
+
+  // Parse a string containing a single JSON value.
+  Handle<Object> ParseJson(Handle<String>);
+  // Parse a single JSON value from input (grammar production JSONValue).
+  // A JSON value is either a (double-quoted) string literal, a number literal,
+  // one of "true", "false", or "null", or an object or array literal.
+  Handle<Object> ParseJsonValue();
+  // Parse a JSON object literal (grammar production JSONObject).
+  // An object literal is a squiggly-braced and comma separated sequence
+  // (possibly empty) of key/value pairs, where the key is a JSON string
+  // literal, the value is a JSON value, and the two are separated by a colon.
+  // A JSON array dosn't allow numbers and identifiers as keys, like a
+  // JavaScript array.
+  Handle<Object> ParseJsonObject();
+  // Parses a JSON array literal (grammar production JSONArray). An array
+  // literal is a square-bracketed and comma separated sequence (possibly empty)
+  // of JSON values.
+  // A JSON array doesn't allow leaving out values from the sequence, nor does
+  // it allow a terminal comma, like a JavaScript array does.
+  Handle<Object> ParseJsonArray();
+
+  // Mark that a parsing error has happened at the current token, and
+  // return a null handle. Primarily for readability.
+  Handle<Object> ReportUnexpectedToken() { return Handle<Object>::null(); }
+  // Converts the currently parsed literal to a JavaScript String.
+  Handle<String> GetString();
+
+  Scanner scanner_;
+};
 } }  // namespace v8::internal
 
 #endif  // V8_PARSER_H_

src/runtime.cc

@@ -7129,20 +7129,31 @@ static MaybeObject* Runtime_GlobalReceiver(Arguments args) {
 }
 
 
+static MaybeObject* Runtime_ParseJson(Arguments args) {
+  HandleScope scope;
+  ASSERT_EQ(1, args.length());
+  CONVERT_ARG_CHECKED(String, source, 0);
+
+  Handle<Object> result = JsonParser::Parse(source);
+  if (result.is_null()) {
+    // Syntax error or stack overflow in scanner.
+    ASSERT(Top::has_pending_exception());
+    return Failure::Exception();
+  }
+  return *result;
+}
+
+
 static MaybeObject* Runtime_CompileString(Arguments args) {
   HandleScope scope;
-  ASSERT_EQ(2, args.length());
+  ASSERT_EQ(1, args.length());
   CONVERT_ARG_CHECKED(String, source, 0);
-  CONVERT_ARG_CHECKED(Oddball, is_json, 1)
 
   // Compile source string in the global context.
   Handle<Context> context(Top::context()->global_context());
-  Compiler::ValidationState validate = (is_json->IsTrue())
-    ? Compiler::VALIDATE_JSON : Compiler::DONT_VALIDATE_JSON;
   Handle<SharedFunctionInfo> shared = Compiler::CompileEval(source,
                                                             context,
-                                                            true,
-                                                            validate);
+                                                            true);
   if (shared.is_null()) return Failure::Exception();
   Handle<JSFunction> fun =
       Factory::NewFunctionFromSharedFunctionInfo(shared, context, NOT_TENURED);
@@ -7157,8 +7168,7 @@ static ObjectPair CompileGlobalEval(Handle<String> source,
   Handle<SharedFunctionInfo> shared = Compiler::CompileEval(
       source,
       Handle<Context>(Top::context()),
-      Top::context()->IsGlobalContext(),
-      Compiler::DONT_VALIDATE_JSON);
+      Top::context()->IsGlobalContext());
   if (shared.is_null()) return MakePair(Failure::Exception(), NULL);
   Handle<JSFunction> compiled = Factory::NewFunctionFromSharedFunctionInfo(
       shared,
@@ -9370,8 +9380,7 @@ static MaybeObject* Runtime_DebugEvaluate(Arguments args) {
   Handle<SharedFunctionInfo> shared =
       Compiler::CompileEval(function_source,
                             context,
-                            context->IsGlobalContext(),
-                            Compiler::DONT_VALIDATE_JSON);
+                            context->IsGlobalContext());
   if (shared.is_null()) return Failure::Exception();
   Handle<JSFunction> compiled_function =
       Factory::NewFunctionFromSharedFunctionInfo(shared, context);
@@ -9442,8 +9451,7 @@ static MaybeObject* Runtime_DebugEvaluateGlobal(Arguments args) {
   Handle<SharedFunctionInfo> shared =
       Compiler::CompileEval(source,
                             context,
-                            true,
-                            Compiler::DONT_VALIDATE_JSON);
+                            true);
   if (shared.is_null()) return Failure::Exception();
   Handle<JSFunction> compiled_function =
       Handle<JSFunction>(Factory::NewFunctionFromSharedFunctionInfo(shared,

src/runtime.h

@@ -164,6 +164,9 @@ namespace internal {
   F(RegExpConstructResult, 3, 1) \
   F(RegExpCloneResult, 1, 1) \
   \
+  /* JSON */ \
+  F(ParseJson, 1, 1) \
+  \
   /* Strings */ \
   F(StringCharCodeAt, 2, 1) \
   F(StringIndexOf, 3, 1) \
@@ -222,7 +225,7 @@ namespace internal {
   /* Numbers */ \
   \
   /* Globals */ \
-  F(CompileString, 2, 1) \
+  F(CompileString, 1, 1) \
   F(GlobalPrint, 1, 1) \
   \
   /* Eval */ \

src/scanner.h

@@ -296,6 +296,9 @@ class Scanner {
   // Returns the next token.
   Token::Value Next();
 
+  // Returns the current token again.
+  Token::Value current_token() { return current_.token; }
+
   // One token look-ahead (past the token returned by Next()).
   Token::Value peek() const { return next_.token; }
 

src/v8natives.js

@@ -140,7 +140,7 @@ function GlobalEval(x) {
                          'be the global object from which eval originated');
   }
 
-  var f = %CompileString(x, false);
+  var f = %CompileString(x);
   if (!IS_FUNCTION(f)) return f;
 
   return f.call(this);
@@ -151,7 +151,7 @@ function GlobalEval(x) {
 function GlobalExecScript(expr, lang) {
   // NOTE: We don't care about the character casing.
   if (!lang || /javascript/i.test(lang)) {
-    var f = %CompileString(ToString(expr), false);
+    var f = %CompileString(ToString(expr));
     f.call(%GlobalReceiver(global));
   }
   return null;
@@ -1177,7 +1177,7 @@ function NewFunction(arg1) {  // length == 1
 
   // The call to SetNewFunctionAttributes will ensure the prototype
   // property of the resulting function is enumerable (ECMA262, 15.3.5.2).
-  var f = %CompileString(source, false)();
+  var f = %CompileString(source)();
   %FunctionSetName(f, "anonymous");
   return %SetNewFunctionAttributes(f);
 }

test/mjsunit/debug-compile-event.js

@@ -36,7 +36,6 @@ var current_source = '';  // Current source being compiled.
 var source_count = 0;  // Total number of scources compiled.
 var host_compilations = 0;  // Number of scources compiled through the API.
 var eval_compilations = 0;  // Number of scources compiled through eval.
-var json_compilations = 0;  // Number of scources compiled through JSON.parse.
 
 
 function compileSource(source) {
@@ -62,9 +61,6 @@ function listener(event, exec_state, event_data, data) {
           case Debug.ScriptCompilationType.Eval:
             eval_compilations++;
             break;
-          case Debug.ScriptCompilationType.JSON:
-            json_compilations++;
-            break;
         }
       }
 
@@ -74,13 +70,6 @@ function listener(event, exec_state, event_data, data) {
         // For source with 'eval' there will be compile events with substrings
         // as well as with with the exact source.
         assertTrue(current_source.indexOf(event_data.script().source()) >= 0);
-      } else if (current_source.indexOf('JSON.parse') == 0) {
-        // For JSON the JSON source will be in parentheses.
-        var s = event_data.script().source();
-        if (s[0] == '(') {
-          s = s.substring(1, s.length - 2);
-        }
-        assertTrue(current_source.indexOf(s) >= 0);
       } else {
         // For source without 'eval' there will be a compile events with the
         // exact source.
@@ -113,7 +102,7 @@ source_count++;  // Using eval causes additional compilation event.
 compileSource('eval("eval(\'(function(){return a;})\')")');
 source_count += 2;  // Using eval causes additional compilation event.
 compileSource('JSON.parse(\'{"a":1,"b":2}\')');
-source_count++;  // Using JSON.parse causes additional compilation event.
+// Using JSON.parse does not causes additional compilation events.
 compileSource('x=1; //@ sourceURL=myscript.js');
 
 // Make sure that the debug event listener was invoked.
@@ -123,10 +112,9 @@ assertFalse(exception, "exception in listener")
 assertEquals(before_compile_count, after_compile_count);
 
 // Check the actual number of events (no compilation through the API as all
-// source compiled through eval except for one JSON.parse call).
+// source compiled through eval).
 assertEquals(source_count, after_compile_count);
 assertEquals(0, host_compilations);
-assertEquals(source_count - 1, eval_compilations);
-assertEquals(1, json_compilations);
+assertEquals(source_count, eval_compilations);
 
 Debug.setListener(null);

test/mjsunit/mirror-script.js

@@ -83,12 +83,10 @@ function testScriptMirror(f, file_name, file_lines, type, compilation_type,
 
 
 // Test the script mirror for different functions.
-testScriptMirror(function(){}, 'mirror-script.js', 100, 2, 0);
+testScriptMirror(function(){}, 'mirror-script.js', 98, 2, 0);
 testScriptMirror(Math.sin, 'native math.js', -1, 0, 0);
 testScriptMirror(eval('(function(){})'), null, 1, 2, 1, '(function(){})', 87);
 testScriptMirror(eval('(function(){\n  })'), null, 2, 2, 1, '(function(){\n  })', 88);
-testScriptMirror(%CompileString('{"a":1,"b":2}', true), null, 1, 2, 2, '{"a":1,"b":2}');
-testScriptMirror(%CompileString('{"a":1,\n  "b":2}', true), null, 2, 2, 2, '{"a":1,\n  "b":2}');
 
 // Test taking slices of source.
 var mirror = debug.MakeMirror(eval('(function(){\n  1;\n})')).script();