ES6 symbols: turn symbols into a proper primitive type

src/ia32/lithium-codegen-ia32.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 2098 matching lines @@
         // String value -> false iff empty.
         Label not_string;
         __ CmpInstanceType(map, FIRST_NONSTRING_TYPE);
         __ j(above_equal, &not_string, Label::kNear);
         __ cmp(FieldOperand(reg, String::kLengthOffset), Immediate(0));
         __ j(not_zero, true_label);
         __ jmp(false_label);
         __ bind(&not_string);
       }
 
+      if (expected.Contains(ToBooleanStub::SYMBOL)) {
+        // Symbol value -> true.
+        __ CmpInstanceType(map, SYMBOL_TYPE);
+        __ j(equal, true_label);
+      }
+
       if (expected.Contains(ToBooleanStub::HEAP_NUMBER)) {
         // heap number -> false iff +0, -0, or NaN.
         Label not_heap_number;
         __ cmp(FieldOperand(reg, HeapObject::kMapOffset),
                factory()->heap_number_map());
         __ j(not_equal, &not_heap_number, Label::kNear);
         __ xorps(xmm0, xmm0);
         __ ucomisd(xmm0, FieldOperand(reg, HeapNumber::kValueOffset));
         __ j(zero, false_label);
         __ jmp(true_label);
@@ skipping 3843 matching lines @@
     final_branch_condition = equal;
 
   } else if (type_name->Equals(heap()->string_string())) {
     __ JumpIfSmi(input, false_label);
     __ CmpObjectType(input, FIRST_NONSTRING_TYPE, input);
     __ j(above_equal, false_label);
     __ test_b(FieldOperand(input, Map::kBitFieldOffset),
               1 << Map::kIsUndetectable);
     final_branch_condition = zero;
 
+  } else if (type_name->Equals(heap()->symbol_string())) {
+    __ JumpIfSmi(input, false_label);
+    __ CmpObjectType(input, SYMBOL_TYPE, input);
+    final_branch_condition = equal;
+
   } else if (type_name->Equals(heap()->boolean_string())) {
     __ cmp(input, factory()->true_value());
     __ j(equal, true_label);
     __ cmp(input, factory()->false_value());
     final_branch_condition = equal;
 
   } else if (FLAG_harmony_typeof && type_name->Equals(heap()->null_string())) {
     __ cmp(input, factory()->null_value());
     final_branch_condition = equal;
 
@@ skipping 14 matching lines @@
     __ j(equal, true_label);
     __ CmpInstanceType(input, JS_FUNCTION_PROXY_TYPE);
     final_branch_condition = equal;
 
   } else if (type_name->Equals(heap()->object_string())) {
     __ JumpIfSmi(input, false_label);
     if (!FLAG_harmony_typeof) {
       __ cmp(input, factory()->null_value());
       __ j(equal, true_label);
     }
-    if (FLAG_harmony_symbols) {
-      __ CmpObjectType(input, SYMBOL_TYPE, input);
-      __ j(equal, true_label);
-      __ CmpInstanceType(input, FIRST_NONCALLABLE_SPEC_OBJECT_TYPE);
-    } else {
-      __ CmpObjectType(input, FIRST_NONCALLABLE_SPEC_OBJECT_TYPE, input);
-    }
+    __ CmpObjectType(input, FIRST_NONCALLABLE_SPEC_OBJECT_TYPE, input);
     __ j(below, false_label);
     __ CmpInstanceType(input, LAST_NONCALLABLE_SPEC_OBJECT_TYPE);
     __ j(above, false_label);
     // Check for undetectable objects => false.
     __ test_b(FieldOperand(input, Map::kBitFieldOffset),
               1 << Map::kIsUndetectable);
     final_branch_condition = zero;
 
   } else {
     __ jmp(false_label);
@@ skipping 261 matching lines @@
                               FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32