Unify the handling of comparinsons against null and undefined.

src/arm/full-codegen-arm.cc

 // Copyright 2011 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 3885 matching lines @@
 
     context()->Plug(r0);
   } else {
     // This expression cannot throw a reference error at the top level.
     VisitInCurrentContext(expr);
   }
 }
 
 
 void FullCodeGenerator::EmitLiteralCompareTypeof(Expression* expr,
-                                                 Handle<String> check,
-                                                 Label* if_true,
-                                                 Label* if_false,
-                                                 Label* fall_through) {
+                                                 Handle<String> check) {
+  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);
+
   { AccumulatorValueContext context(this);
     VisitForTypeofValue(expr);
   }
   PrepareForBailoutBeforeSplit(TOS_REG, true, if_true, if_false);
 
   if (check->Equals(isolate()->heap()->number_symbol())) {
     __ JumpIfSmi(r0, if_true);
     __ ldr(r0, FieldMemOperand(r0, HeapObject::kMapOffset));
     __ LoadRoot(ip, Heap::kHeapNumberMapRootIndex);
     __ cmp(r0, ip);
@@ skipping 41 matching lines @@
     __ b(lt, if_false);
     __ CompareInstanceType(r0, r1, LAST_NONCALLABLE_SPEC_OBJECT_TYPE);
     __ b(gt, if_false);
     // Check for undetectable objects => false.
     __ ldrb(r1, FieldMemOperand(r0, Map::kBitFieldOffset));
     __ tst(r1, Operand(1 << Map::kIsUndetectable));
     Split(eq, if_true, if_false, fall_through);
   } else {
     if (if_false != fall_through) __ jmp(if_false);
   }
-}
-
-
-void FullCodeGenerator::EmitLiteralCompareUndefined(Expression* expr,
-                                                    Label* if_true,
-                                                    Label* if_false,
-                                                    Label* fall_through) {
-  VisitForAccumulatorValue(expr);
-  PrepareForBailoutBeforeSplit(TOS_REG, true, if_true, if_false);
-
-  __ CompareRoot(r0, Heap::kUndefinedValueRootIndex);
-  Split(eq, if_true, if_false, fall_through);
+  context()->Plug(if_true, if_false);
 }
 
 
 void FullCodeGenerator::VisitCompareOperation(CompareOperation* expr) {
   Comment cmnt(masm_, "[ CompareOperation");
   SetSourcePosition(expr->position());
 
+  // First we try a fast inlined version of the compare when one of
+  // the operands is a literal.
+  if (TryLiteralCompare(expr)) return;
+
   // Always perform the comparison for its control flow.  Pack the result
   // into the expression's context after the comparison is performed.
-
   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);
 
-  // First we try a fast inlined version of the compare when one of
-  // the operands is a literal.
-  if (TryLiteralCompare(expr, if_true, if_false, fall_through)) {
-    context()->Plug(if_true, if_false);
-    return;
-  }
-
   Token::Value op = expr->op();
   VisitForStackValue(expr->left());
   switch (op) {
     case Token::IN:
       VisitForStackValue(expr->right());
       __ InvokeBuiltin(Builtins::IN, CALL_FUNCTION);
       PrepareForBailoutBeforeSplit(TOS_REG, false, NULL, NULL);
       __ LoadRoot(ip, Heap::kTrueValueRootIndex);
       __ cmp(r0, ip);
       Split(eq, if_true, if_false, fall_through);
@@ skipping 66 matching lines @@
       Split(cond, if_true, if_false, fall_through);
     }
   }
 
   // Convert the result of the comparison into one expected for this
   // expression's context.
   context()->Plug(if_true, if_false);
 }
 
 
-void FullCodeGenerator::EmitLiteralCompareNull(Expression* expr,
-                                               bool is_strict,
-                                               Label* if_true,
-                                               Label* if_false,
-                                               Label* fall_through) {
-  VisitForAccumulatorValue(expr);
+void FullCodeGenerator::EmitLiteralCompareNil(CompareOperation* expr,
+                                              Expression* sub_expr,
+                                              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(TOS_REG, true, if_true, if_false);
-  __ LoadRoot(r1, Heap::kNullValueRootIndex);
+  Heap::RootListIndex nil_value = nil == kNullValue ?
+      Heap::kNullValueRootIndex :
+      Heap::kUndefinedValueRootIndex;
+  __ LoadRoot(r1, nil_value);
   __ cmp(r0, r1);
-  if (is_strict) {
+  if (expr->op() == Token::EQ_STRICT) {
     Split(eq, if_true, if_false, fall_through);
   } else {
+    Heap::RootListIndex other_nil_value = nil == kNullValue ?
+        Heap::kUndefinedValueRootIndex :
+        Heap::kNullValueRootIndex;
     __ b(eq, if_true);
-    __ LoadRoot(r1, Heap::kUndefinedValueRootIndex);
+    __ LoadRoot(r1, other_nil_value);
     __ cmp(r0, r1);
     __ b(eq, if_true);
     __ JumpIfSmi(r0, if_false);
     // It can be an undetectable object.
     __ ldr(r1, FieldMemOperand(r0, HeapObject::kMapOffset));
     __ ldrb(r1, FieldMemOperand(r1, Map::kBitFieldOffset));
     __ and_(r1, r1, Operand(1 << Map::kIsUndetectable));
     __ cmp(r1, Operand(1 << Map::kIsUndetectable));
     Split(eq, if_true, if_false, fall_through);
   }
+  context()->Plug(if_true, if_false);
 }
 
 
 void FullCodeGenerator::VisitThisFunction(ThisFunction* expr) {
   __ ldr(r0, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
   context()->Plug(r0);
 }
 
 
 Register FullCodeGenerator::result_register() {
@@ skipping 92 matching lines @@
   *context_length = 0;
   return previous_;
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM