Optimize calls to evals. Most of the time there is no reason to...

src/runtime.cc

Index: src/runtime.cc
===================================================================
--- src/runtime.cc	(revision 4792)
+++ src/runtime.cc	(working copy)
@@ -7245,6 +7245,24 @@
 }
 
 
+static ObjectPair CompileGlobalEval(Handle<String> source,
+                                    Handle<Object> receiver) {
+  // Deal with a normal eval call with a string argument. Compile it
+  // and return the compiled function bound in the local context.
+  Handle<SharedFunctionInfo> shared = Compiler::CompileEval(
+      source,
+      Handle<Context>(Top::context()),
+      Top::context()->IsGlobalContext(),
+      Compiler::DONT_VALIDATE_JSON);
+  if (shared.is_null()) return MakePair(Failure::Exception(), NULL);
+  Handle<JSFunction> compiled = Factory::NewFunctionFromSharedFunctionInfo(
+      shared,
+      Handle<Context>(Top::context()),
+      NOT_TENURED);
+  return MakePair(*compiled, *receiver);
+}
+
+
 static ObjectPair Runtime_ResolvePossiblyDirectEval(Arguments args) {
   ASSERT(args.length() == 3);
   if (!args[0]->IsJSFunction()) {
@@ -7310,23 +7328,30 @@
     return MakePair(*callee, Top::context()->global()->global_receiver());
   }
 
-  // Deal with a normal eval call with a string argument. Compile it
-  // and return the compiled function bound in the local context.
-  Handle<String> source = args.at<String>(1);
-  Handle<SharedFunctionInfo> shared = Compiler::CompileEval(
-      source,
-      Handle<Context>(Top::context()),
-      Top::context()->IsGlobalContext(),
-      Compiler::DONT_VALIDATE_JSON);
-  if (shared.is_null()) return MakePair(Failure::Exception(), NULL);
-  callee = Factory::NewFunctionFromSharedFunctionInfo(
-      shared,
-      Handle<Context>(Top::context()),
-      NOT_TENURED);
-  return MakePair(*callee, args[2]);
+  return CompileGlobalEval(args.at<String>(1), args.at<Object>(2));
 }
 
 
+static ObjectPair Runtime_ResolvePossiblyDirectEvalNoLookup(Arguments args) {
+  ASSERT(args.length() == 3);
+  if (!args[0]->IsJSFunction()) {
+    return MakePair(Top::ThrowIllegalOperation(), NULL);
+  }
+
+  HandleScope scope;
+  Handle<JSFunction> callee = args.at<JSFunction>(0);
+
+  // 'eval' is bound in the global context, but it may have been overwritten.
+  // Compare it to the builtin 'GlobalEval' function to make sure.
+  if (*callee != Top::global_context()->global_eval_fun() ||
+      !args[1]->IsString()) {
+    return MakePair(*callee, Top::context()->global()->global_receiver());
+  }
+
+  return CompileGlobalEval(args.at<String>(1), args.at<Object>(2));
+}
+
+
 static Object* Runtime_SetNewFunctionAttributes(Arguments args) {
   // This utility adjusts the property attributes for newly created Function
   // object ("new Function(...)") by changing the map.