ES6 symbols: turn symbols into a proper primitive type

src/arm/full-codegen-arm.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 2746 matching lines @@
   __ ldrb(r2, FieldMemOperand(r1, Map::kBitField2Offset));
   __ orr(r2, r2, Operand(1 << Map::kStringWrapperSafeForDefaultValueOf));
   __ strb(r2, FieldMemOperand(r1, Map::kBitField2Offset));
   __ jmp(if_true);
 
   PrepareForBailoutBeforeSplit(expr, true, if_true, if_false);
   context()->Plug(if_true, if_false);
 }
 
 
-void FullCodeGenerator::EmitIsSymbol(CallRuntime* expr) {
-  ZoneList<Expression*>* args = expr->arguments();
-  ASSERT(args->length() == 1);
-
-  VisitForAccumulatorValue(args->at(0));
-
-  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);
-
-  __ JumpIfSmi(r0, if_false);
-  __ CompareObjectType(r0, r1, r2, SYMBOL_TYPE);
-  PrepareForBailoutBeforeSplit(expr, true, if_true, if_false);
-  Split(eq, if_true, if_false, fall_through);
-
-  context()->Plug(if_true, if_false);
-}
-
-
 void FullCodeGenerator::EmitIsFunction(CallRuntime* expr) {
   ZoneList<Expression*>* args = expr->arguments();
   ASSERT(args->length() == 1);
 
   VisitForAccumulatorValue(args->at(0));
 
   Label materialize_true, materialize_false;
   Label* if_true = NULL;
   Label* if_false = NULL;
   Label* fall_through = NULL;
@@ skipping 1486 matching lines @@
     __ cmp(r0, ip);
     Split(eq, if_true, if_false, fall_through);
   } else if (check->Equals(isolate()->heap()->string_string())) {
     __ JumpIfSmi(r0, if_false);
     // Check for undetectable objects => false.
     __ CompareObjectType(r0, r0, r1, FIRST_NONSTRING_TYPE);
     __ b(ge, if_false);
     __ ldrb(r1, FieldMemOperand(r0, Map::kBitFieldOffset));
     __ tst(r1, Operand(1 << Map::kIsUndetectable));
     Split(eq, if_true, if_false, fall_through);
+  } else if (check->Equals(isolate()->heap()->symbol_string())) {
+    __ JumpIfSmi(r0, if_false);
+    __ CompareObjectType(r0, r0, r1, SYMBOL_TYPE);
+    Split(eq, if_true, if_false, fall_through);
   } else if (check->Equals(isolate()->heap()->boolean_string())) {
     __ CompareRoot(r0, Heap::kTrueValueRootIndex);
     __ b(eq, if_true);
     __ CompareRoot(r0, Heap::kFalseValueRootIndex);
     Split(eq, if_true, if_false, fall_through);
   } else if (FLAG_harmony_typeof &&
              check->Equals(isolate()->heap()->null_string())) {
     __ CompareRoot(r0, Heap::kNullValueRootIndex);
     Split(eq, if_true, if_false, fall_through);
   } else if (check->Equals(isolate()->heap()->undefined_string())) {
@@ skipping 12 matching lines @@
     __ CompareObjectType(r0, r0, r1, JS_FUNCTION_TYPE);
     __ b(eq, if_true);
     __ cmp(r1, Operand(JS_FUNCTION_PROXY_TYPE));
     Split(eq, if_true, if_false, fall_through);
   } else if (check->Equals(isolate()->heap()->object_string())) {
     __ JumpIfSmi(r0, if_false);
     if (!FLAG_harmony_typeof) {
       __ CompareRoot(r0, Heap::kNullValueRootIndex);
       __ b(eq, if_true);
     }
-    if (FLAG_harmony_symbols) {
-      __ CompareObjectType(r0, r0, r1, SYMBOL_TYPE);
-      __ b(eq, if_true);
-    }
     // Check for JS objects => true.
     __ CompareObjectType(r0, r0, r1, FIRST_NONCALLABLE_SPEC_OBJECT_TYPE);
     __ 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 {
@@ skipping 261 matching lines @@
   *context_length = 0;
   return previous_;
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM