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

src/full-codegen/arm/full-codegen-arm.cc

 // Copyright 2012 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_ARM
 
 #include "src/ast/scopes.h"
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/codegen.h"
@@ skipping 519 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 3741 matching lines @@
   } else if (String::Equals(check, factory->symbol_string())) {
     __ JumpIfSmi(r0, if_false);
     __ CompareObjectType(r0, r0, r1, SYMBOL_TYPE);
     Split(eq, if_true, if_false, fall_through);
   } else if (String::Equals(check, factory->boolean_string())) {
     __ CompareRoot(r0, Heap::kTrueValueRootIndex);
     __ b(eq, if_true);
     __ CompareRoot(r0, Heap::kFalseValueRootIndex);
     Split(eq, if_true, if_false, fall_through);
   } else if (String::Equals(check, factory->undefined_string())) {
-    __ CompareRoot(r0, Heap::kUndefinedValueRootIndex);
-    __ b(eq, if_true);
+    __ CompareRoot(r0, Heap::kNullValueRootIndex);
+    __ b(eq, if_false);
     __ JumpIfSmi(r0, if_false);
     // Check for undetectable objects => true.
     __ ldr(r0, FieldMemOperand(r0, HeapObject::kMapOffset));
     __ ldrb(r1, FieldMemOperand(r0, Map::kBitFieldOffset));
     __ tst(r1, Operand(1 << Map::kIsUndetectable));
     Split(ne, if_true, if_false, fall_through);
 
   } else if (String::Equals(check, factory->function_string())) {
     __ JumpIfSmi(r0, if_false);
     __ ldr(r0, FieldMemOperand(r0, HeapObject::kMapOffset));
@@ skipping 388 matching lines @@
   DCHECK(interrupt_address ==
          isolate->builtins()->OsrAfterStackCheck()->entry());
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_ARM