Add monomorphic CompareNilICs and Crankshaft support

src/x64/full-codegen-x64.cc

 // Copyright 2012 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 4417 matching lines @@
                                               NilValue nil) {
   Label materialize_true, materialize_false;
   Label* if_true = NULL;
   Label* if_false = NULL;
   Label* fall_through = NULL;
   context()->PrepareTest(&materialize_true, &materialize_false,
                          &if_true, &if_false, &fall_through);
 
   VisitForAccumulatorValue(sub_expr);
   PrepareForBailoutBeforeSplit(expr, true, if_true, if_false);
-  Heap::RootListIndex nil_value = nil == kNullValue ?
-      Heap::kNullValueRootIndex :
-      Heap::kUndefinedValueRootIndex;
-  __ CompareRoot(rax, nil_value);
-  if (expr->op() == Token::EQ_STRICT) {
+  EqualityKind kind = expr->op() == Token::EQ_STRICT
+      ? kStrictEquality : kNonStrictEquality;
+  if (kind == kStrictEquality) {
+    Heap::RootListIndex nil_value = nil == kNullValue ?
+        Heap::kNullValueRootIndex :
+        Heap::kUndefinedValueRootIndex;
+    __ CompareRoot(rax, nil_value);
     Split(equal, if_true, if_false, fall_through);
   } else {
-    Heap::RootListIndex other_nil_value = nil == kNullValue ?
-        Heap::kUndefinedValueRootIndex :
-        Heap::kNullValueRootIndex;
-    __ j(equal, if_true);
-    __ CompareRoot(rax, other_nil_value);
-    __ j(equal, if_true);
-    __ JumpIfSmi(rax, if_false);
-    // It can be an undetectable object.
-    __ movq(rdx, FieldOperand(rax, HeapObject::kMapOffset));
-    __ testb(FieldOperand(rdx, Map::kBitFieldOffset),
-             Immediate(1 << Map::kIsUndetectable));
+    Handle<Code> ic = CompareNilICStub::GetUninitialized(isolate(),
+                                                         kNonStrictEquality,
+                                                         nil);
+    CallIC(ic, RelocInfo::CODE_TARGET, expr->CompareOperationFeedbackId());
+    __ testq(rax, rax);
     Split(not_zero, if_true, if_false, fall_through);
   }
   context()->Plug(if_true, if_false);
 }
 
 
 void FullCodeGenerator::VisitThisFunction(ThisFunction* expr) {
   __ movq(rax, Operand(rbp, JavaScriptFrameConstants::kFunctionOffset));
   context()->Plug(rax);
 }
@@ skipping 135 matching lines @@
   *context_length = 0;
   return previous_;
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64