Avoid calling ToObject on JSFunction receiver arguments for Function.call and Function.apply.

src/mips/builtins-mips.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1205 matching lines @@
     // a1: function
     // a2: first argument
     __ JumpIfSmi(a2, &convert_to_object, t2);
 
     __ LoadRoot(a3, Heap::kUndefinedValueRootIndex);
     __ Branch(&use_global_receiver, eq, a2, Operand(a3));
     __ LoadRoot(a3, Heap::kNullValueRootIndex);
     __ Branch(&use_global_receiver, eq, a2, Operand(a3));
 
     __ GetObjectType(a2, a3, a3);
-    __ Branch(&convert_to_object, lt, a3, Operand(FIRST_JS_OBJECT_TYPE));
-    __ Branch(&shift_arguments, le, a3, Operand(LAST_JS_OBJECT_TYPE));
+    __ Branch(&shift_arguments, ge, a3, Operand(FIRST_JS_OBJECT_TYPE));

[Vyacheslav Egorov (Chromium), 2011/05/23 14:58:01]

add an assertion that LAST_TYPE == JS_FUNCTION_TYPE?

 
     __ bind(&convert_to_object);
     __ EnterInternalFrame();  // In order to preserve argument count.
     __ sll(a0, a0, kSmiTagSize);  // Smi tagged.
     __ push(a0);
 
     __ push(a2);
     __ InvokeBuiltin(Builtins::TO_OBJECT, CALL_FUNCTION);
     __ mov(a2, v0);
 
@@ skipping 157 matching lines @@
   __ And(t0, a0, Operand(kSmiTagMask));
   __ Branch(&call_to_object, eq, t0, Operand(zero_reg));
   __ LoadRoot(a1, Heap::kNullValueRootIndex);
   __ Branch(&use_global_receiver, eq, a0, Operand(a1));
   __ LoadRoot(a2, Heap::kUndefinedValueRootIndex);
   __ Branch(&use_global_receiver, eq, a0, Operand(a2));
 
   // Check if the receiver is already a JavaScript object.
   // a0: receiver
   __ GetObjectType(a0, a1, a1);
-  __ Branch(&call_to_object, lt, a1, Operand(FIRST_JS_OBJECT_TYPE));
-  __ Branch(&push_receiver, le, a1, Operand(LAST_JS_OBJECT_TYPE));
+  __ Branch(&push_receiver, ge, a1, Operand(FIRST_JS_OBJECT_TYPE));
 
   // Convert the receiver to a regular object.
   // a0: receiver
   __ bind(&call_to_object);
   __ push(a0);
   __ InvokeBuiltin(Builtins::TO_OBJECT, CALL_FUNCTION);
   __ mov(a0, v0);  // Put object in a0 to match other paths to push_receiver.
   __ Branch(&push_receiver);
 
   // Use the current global receiver object as the receiver.
@@ skipping 186 matching lines @@
   __ bind(&dont_adapt_arguments);
   __ Jump(a3);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_MIPS