[es6] Initial steps towards a correct implementation of IsCallable.

src/x64/lithium-codegen-x64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/cpu-profiler.h"
@@ skipping 5593 matching lines @@
     __ CompareRoot(input, Heap::kUndefinedValueRootIndex);
     __ j(equal, true_label, true_distance);
     __ JumpIfSmi(input, false_label, false_distance);
     // Check for undetectable objects => true.
     __ movp(input, FieldOperand(input, HeapObject::kMapOffset));
     __ testb(FieldOperand(input, Map::kBitFieldOffset),
              Immediate(1 << Map::kIsUndetectable));
     final_branch_condition = not_zero;
 
   } else if (String::Equals(type_name, factory->function_string())) {
-    STATIC_ASSERT(NUM_OF_CALLABLE_SPEC_OBJECT_TYPES == 2);
     __ JumpIfSmi(input, false_label, false_distance);
-    __ CmpObjectType(input, JS_FUNCTION_TYPE, input);
-    __ j(equal, true_label, true_distance);
-    __ CmpInstanceType(input, JS_FUNCTION_PROXY_TYPE);
+    // Check for callable and not undetectable objects => true.
+    __ movp(input, FieldOperand(input, HeapObject::kMapOffset));
+    __ movzxbl(input, FieldOperand(input, Map::kBitFieldOffset));
+    __ andb(input,
+            Immediate((1 << Map::kIsCallable) | (1 << Map::kIsUndetectable)));
+    __ cmpb(input, Immediate(1 << Map::kIsCallable));
     final_branch_condition = equal;
 
   } else if (String::Equals(type_name, factory->object_string())) {
     __ JumpIfSmi(input, false_label, false_distance);
     __ CompareRoot(input, Heap::kNullValueRootIndex);
     __ j(equal, true_label, true_distance);
-    __ CmpObjectType(input, FIRST_NONCALLABLE_SPEC_OBJECT_TYPE, input);
+    STATIC_ASSERT(LAST_SPEC_OBJECT_TYPE == LAST_TYPE);
+    __ CmpObjectType(input, FIRST_SPEC_OBJECT_TYPE, input);
     __ j(below, false_label, false_distance);
-    __ CmpInstanceType(input, LAST_NONCALLABLE_SPEC_OBJECT_TYPE);
-    __ j(above, false_label, false_distance);
-    // Check for undetectable objects => false.
+    // Check for callable or undetectable objects => false.
     __ testb(FieldOperand(input, Map::kBitFieldOffset),
-             Immediate(1 << Map::kIsUndetectable));
+             Immediate((1 << Map::kIsCallable) | (1 << Map::kIsUndetectable)));
     final_branch_condition = zero;
 
 // clang-format off
 #define SIMD128_TYPE(TYPE, Type, type, lane_count, lane_type)       \
   } else if (String::Equals(type_name, factory->type##_string())) { \
     __ JumpIfSmi(input, false_label, false_distance);               \
-    __ movp(input, FieldOperand(input, HeapObject::kMapOffset));    \
-    __ CompareRoot(input, Heap::k##Type##MapRootIndex);             \
+    __ CompareRoot(FieldOperand(input, HeapObject::kMapOffset),     \
+                   Heap::k##Type##MapRootIndex);                    \
     final_branch_condition = equal;
   SIMD128_TYPES(SIMD128_TYPE)
 #undef SIMD128_TYPE
     // clang-format on
 
   } else {
     __ jmp(false_label, false_distance);
   }
 
   return final_branch_condition;
@@ skipping 289 matching lines @@
   RecordSafepoint(Safepoint::kNoLazyDeopt);
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64