[es5] Class of object is "Function" if object has [[Call]].

src/x64/lithium-codegen-x64.cc

Index: src/x64/lithium-codegen-x64.cc
diff --git a/src/x64/lithium-codegen-x64.cc b/src/x64/lithium-codegen-x64.cc
index 250589097452890ef6631493e43d4ccf17269d27..322de11f5d267a89d9cc18eb1aa4527d6062ce04 100644
--- a/src/x64/lithium-codegen-x64.cc
+++ b/src/x64/lithium-codegen-x64.cc
@@ -2572,32 +2572,20 @@ void LCodeGen::EmitClassOfTest(Label* is_true,
 
   __ JumpIfSmi(input, is_false);
 
+  STATIC_ASSERT(LAST_JS_RECEIVER_TYPE == LAST_TYPE);
+  __ CmpObjectType(input, FIRST_JS_RECEIVER_TYPE, temp);
+  __ j(below, is_false);
+
+  // Objects with [[Call]] have class 'Function'.
+  __ testb(FieldOperand(temp, Map::kBitFieldOffset),
+           Immediate(1 << Map::kIsCallable));
   if (String::Equals(isolate()->factory()->Function_string(), class_name)) {
-    // Assuming the following assertions, we can use the same compares to test
-    // for both being a function type and being in the object type range.
-    STATIC_ASSERT(NUM_OF_CALLABLE_SPEC_OBJECT_TYPES == 2);
-    STATIC_ASSERT(FIRST_NONCALLABLE_SPEC_OBJECT_TYPE ==
-                  FIRST_SPEC_OBJECT_TYPE + 1);
-    STATIC_ASSERT(LAST_NONCALLABLE_SPEC_OBJECT_TYPE ==
-                  LAST_SPEC_OBJECT_TYPE - 1);
-    STATIC_ASSERT(LAST_SPEC_OBJECT_TYPE == LAST_TYPE);
-    __ CmpObjectType(input, FIRST_SPEC_OBJECT_TYPE, temp);
-    __ j(below, is_false);
-    __ j(equal, is_true);
-    __ CmpInstanceType(temp, LAST_SPEC_OBJECT_TYPE);
-    __ j(equal, is_true);
+    __ j(not_zero, is_true);
   } else {
-    // Faster code path to avoid two compares: subtract lower bound from the
-    // actual type and do a signed compare with the width of the type range.
-    __ movp(temp, FieldOperand(input, HeapObject::kMapOffset));
-    __ movzxbl(temp2, FieldOperand(temp, Map::kInstanceTypeOffset));
-    __ subp(temp2, Immediate(FIRST_NONCALLABLE_SPEC_OBJECT_TYPE));
-    __ cmpp(temp2, Immediate(LAST_NONCALLABLE_SPEC_OBJECT_TYPE -
-                             FIRST_NONCALLABLE_SPEC_OBJECT_TYPE));
-    __ j(above, is_false);
+    __ j(not_zero, is_false);
   }
 
-  // Now we are in the FIRST-LAST_NONCALLABLE_SPEC_OBJECT_TYPE range.
+  // Now we are in the FIRST-LAST_JS_RECEIVER_TYPE range.
   // Check if the constructor in the map is a function.
   __ GetMapConstructor(temp, temp, kScratchRegister);