Reland "Allow inlining of functions containing %_ArgumentsLength."

The layout test failures were unrelated to this change.

R=svenpanne@chromium.org
TBR=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/355993002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22038 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/ast.cc

@@ -1117,11 +1117,9 @@ void AstConstructionVisitor::VisitCallRuntime(CallRuntime* node) {
     // optimize them.
     add_flag(kDontInline);
   } else if (node->function()->intrinsic_type == Runtime::INLINE &&
-             (node->raw_name()->IsOneByteEqualTo("_ArgumentsLength") ||
-              node->raw_name()->IsOneByteEqualTo("_Arguments"))) {
-    // Don't inline the %_ArgumentsLength or %_Arguments because their
-    // implementation will not work.  There is no stack frame to get them
-    // from.
+             node->raw_name()->IsOneByteEqualTo("_Arguments")) {
+    // Don't inline the %_Arguments because it's implementation will not work.
+    // There is no stack frame to get them from.
     add_flag(kDontInline);
   }
 }

src/hydrogen.cc

@@ -11310,13 +11310,17 @@ void HOptimizedGraphBuilder::GenerateIsConstructCall(CallRuntime* call) {
 
 // Support for arguments.length and arguments[?].
 void HOptimizedGraphBuilder::GenerateArgumentsLength(CallRuntime* call) {
-  // Our implementation of arguments (based on this stack frame or an
-  // adapter below it) does not work for inlined functions.  This runtime
-  // function is blacklisted by AstNode::IsInlineable.
-  ASSERT(function_state()->outer() == NULL);
   ASSERT(call->arguments()->length() == 0);
-  HInstruction* elements = Add<HArgumentsElements>(false);
-  HArgumentsLength* result = New<HArgumentsLength>(elements);
+  HInstruction* result = NULL;
+  if (function_state()->outer() == NULL) {
+    HInstruction* elements = Add<HArgumentsElements>(false);
+    result = New<HArgumentsLength>(elements);
+  } else {
+    // Number of arguments without receiver.
+    int argument_count = environment()->
+        arguments_environment()->parameter_count() - 1;
+    result = New<HConstant>(argument_count);
+  }
   return ast_context()->ReturnInstruction(result, call->id());
 }