Mark null and undefined as undetectable, and use it to handle abstract equality comparison in the g…

src/full-codegen/arm64/full-codegen-arm64.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_ARM64
 
 #include "src/ast/scopes.h"
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/codegen.h"
@@ skipping 513 matching lines @@
   __ Mov(result_register(), Operand(lit));
   __ Push(result_register());
 }
 
 
 void FullCodeGenerator::TestContext::Plug(Handle<Object> lit) const {
   codegen()->PrepareForBailoutBeforeSplit(condition(),
                                           true,
                                           true_label_,
                                           false_label_);
-  DCHECK(!lit->IsUndetectableObject());  // There are no undetectable literals.
+  DCHECK(lit->IsNull() || lit->IsUndefined() || !lit->IsUndetectableObject());
   if (lit->IsUndefined() || lit->IsNull() || lit->IsFalse()) {
     if (false_label_ != fall_through_) __ B(false_label_);
   } else if (lit->IsTrue() || lit->IsJSObject()) {
     if (true_label_ != fall_through_) __ B(true_label_);
   } else if (lit->IsString()) {
     if (String::cast(*lit)->length() == 0) {
       if (false_label_ != fall_through_) __ B(false_label_);
     } else {
       if (true_label_ != fall_through_) __ B(true_label_);
     }
@@ skipping 3555 matching lines @@
     __ CompareObjectType(x0, x0, x1, SYMBOL_TYPE);
     Split(eq, if_true, if_false, fall_through);
   } else if (String::Equals(check, factory->boolean_string())) {
     ASM_LOCATION("FullCodeGenerator::EmitLiteralCompareTypeof boolean_string");
     __ JumpIfRoot(x0, Heap::kTrueValueRootIndex, if_true);
     __ CompareRoot(x0, Heap::kFalseValueRootIndex);
     Split(eq, if_true, if_false, fall_through);
   } else if (String::Equals(check, factory->undefined_string())) {
     ASM_LOCATION(
         "FullCodeGenerator::EmitLiteralCompareTypeof undefined_string");
-    __ JumpIfRoot(x0, Heap::kUndefinedValueRootIndex, if_true);
+    __ JumpIfRoot(x0, Heap::kNullValueRootIndex, if_false);
     __ JumpIfSmi(x0, if_false);
     // Check for undetectable objects => true.
     __ Ldr(x0, FieldMemOperand(x0, HeapObject::kMapOffset));
     __ Ldrb(x1, FieldMemOperand(x0, Map::kBitFieldOffset));
     __ TestAndSplit(x1, 1 << Map::kIsUndetectable, if_false, if_true,
                     fall_through);
   } else if (String::Equals(check, factory->function_string())) {
     ASM_LOCATION("FullCodeGenerator::EmitLiteralCompareTypeof function_string");
     __ JumpIfSmi(x0, if_false);
     __ Ldr(x0, FieldMemOperand(x0, HeapObject::kMapOffset));
@@ skipping 561 matching lines @@
   }
 
   return INTERRUPT;
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_ARM64