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 f306ea2bc4b03e2632f49f1756b6b8172433af0e..1e9b7f7d525970ae11afa0323b2babafbf5003e2 100644
--- a/src/builtins/builtins-function.cc
+++ b/src/builtins/builtins-function.cc
@@ -32,11 +32,16 @@ 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) {
@@ -46,22 +51,30 @@ MaybeHandle<Object> CreateDynamicFunction(Isolate* isolate,
             isolate, param, Object::ToString(isolate, args.at(i)), 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) {
+      builder.AppendCharacter('\n');
+      parameters_end_pos = builder.Length();
     }
     builder.AppendCString(") {\n");
     if (argc > 0) {
@@ -86,11 +99,12 @@ 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,