Implement new Function.prototype.toString and fix CreateDynamicFunction parsing

src/builtins/builtins-function.cc

Index: src/builtins/builtins-function.cc
diff --git a/src/builtins/builtins-function.cc b/src/builtins/builtins-function.cc
index 6cd1b283ec6f1e144bc1fe8cff3b5a5783da185c..ceec1a4bad959f2342c3730c4533fa016c9a4999 100644
--- a/src/builtins/builtins-function.cc
+++ b/src/builtins/builtins-function.cc
@@ -31,11 +31,16 @@ MaybeHandle<Object> CreateDynamicFunction(Isolate* isolate,
 
   // Build the source string.
   Handle<String> source;
+  int parameters_end_pos = kNoSourcePosition;
   {
     IncrementalStringBuilder builder(isolate);
     builder.AppendCharacter('(');
     builder.AppendCString(token);
-    builder.AppendCharacter('(');
+    if (FLAG_harmony_function_tostring) {
+      builder.AppendCString(" anonymous(");
+    } else {
+      builder.AppendCharacter('(');
+    }
     bool parenthesis_in_arg_string = false;
     if (argc > 1) {
       for (int i = 1; i < argc; ++i) {
@@ -46,24 +51,33 @@ MaybeHandle<Object> CreateDynamicFunction(Isolate* isolate,
             Object);
         param = String::Flatten(param);
         builder.AppendString(param);
-        // If the formal parameters string include ) - an illegal
-        // character - it may make the combined function expression
-        // compile. We avoid this problem by checking for this early on.
-        DisallowHeapAllocation no_gc;  // Ensure vectors stay valid.
-        String::FlatContent param_content = param->GetFlatContent();
-        for (int i = 0, length = param->length(); i < length; ++i) {
-          if (param_content.Get(i) == ')') {
-            parenthesis_in_arg_string = true;
-            break;
+        if (!FLAG_harmony_function_tostring) {
+          // If the formal parameters string include ) - an illegal
+          // character - it may make the combined function expression
+          // compile. We avoid this problem by checking for this early on.
+          DisallowHeapAllocation no_gc;  // Ensure vectors stay valid.
+          String::FlatContent param_content = param->GetFlatContent();
+          for (int i = 0, length = param->length(); i < length; ++i) {
+            if (param_content.Get(i) == ')') {
+              parenthesis_in_arg_string = true;
+              break;
+            }
           }
         }
       }
-      // If the formal parameters include an unbalanced block comment, the
-      // function must be rejected. Since JavaScript does not allow nested
-      // comments we can include a trailing block comment to catch this.
-      builder.AppendCString("\n/*``*/");
+      if (!FLAG_harmony_function_tostring) {
+        // If the formal parameters include an unbalanced block comment, the
+        // function must be rejected. Since JavaScript does not allow nested
+        // comments we can include a trailing block comment to catch this.
+        builder.AppendCString("\n/*``*/");
+      }
+    }
+    if (FLAG_harmony_function_tostring) {
+      parameters_end_pos = builder.Length() + 1;
+      builder.AppendCString("\n) {");
+    } else {
+      builder.AppendCString(") {\n");
     }
-    builder.AppendCString(") {\n");
     if (argc > 0) {
       Handle<String> body;
       ASSIGN_RETURN_ON_EXCEPTION(
@@ -87,11 +101,12 @@ MaybeHandle<Object> CreateDynamicFunction(Isolate* isolate,
   // come from here.
   Handle<JSFunction> function;
   {
-    ASSIGN_RETURN_ON_EXCEPTION(isolate, function,
-                               Compiler::GetFunctionFromString(
-                                   handle(target->native_context(), isolate),
-                                   source, ONLY_SINGLE_FUNCTION_LITERAL),
-                               Object);
+    ASSIGN_RETURN_ON_EXCEPTION(
+        isolate, function,
+        Compiler::GetFunctionFromString(
+            handle(target->native_context(), isolate), source,
+            ONLY_SINGLE_FUNCTION_LITERAL, parameters_end_pos),
+        Object);
     Handle<Object> result;
     ASSIGN_RETURN_ON_EXCEPTION(
         isolate, result,