ES6 symbols: Implement Symbol intrinsic and basic functionality

src/x64/full-codegen-x64.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 2642 matching lines @@
   // default valueOf and set true result.
   __ or_(FieldOperand(rbx, Map::kBitField2Offset),
          Immediate(1 << Map::kStringWrapperSafeForDefaultValueOf));
   __ 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(rax, if_false);
+  __ CmpObjectType(rax, SYMBOL_TYPE, rbx);
+  PrepareForBailoutBeforeSplit(expr, true, if_true, if_false);
+  Split(equal, 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 1579 matching lines @@
     __ CmpObjectType(rax, JS_FUNCTION_TYPE, rdx);
     __ j(equal, if_true);
     __ CmpInstanceType(rdx, JS_FUNCTION_PROXY_TYPE);
     Split(equal, if_true, if_false, fall_through);
   } else if (check->Equals(isolate()->heap()->object_string())) {
     __ JumpIfSmi(rax, if_false);
     if (!FLAG_harmony_typeof) {
       __ CompareRoot(rax, Heap::kNullValueRootIndex);
       __ j(equal, if_true);
     }
+    if (FLAG_harmony_symbols) {
+      __ CmpObjectType(rax, SYMBOL_TYPE, rdx);
+      __ j(equal, if_true);
+    }
     __ CmpObjectType(rax, FIRST_NONCALLABLE_SPEC_OBJECT_TYPE, rdx);
     __ j(below, if_false);
     __ CmpInstanceType(rdx, LAST_NONCALLABLE_SPEC_OBJECT_TYPE);
     __ j(above, if_false);
     // Check for undetectable objects => false.
     __ testb(FieldOperand(rdx, Map::kBitFieldOffset),
              Immediate(1 << Map::kIsUndetectable));
     Split(zero, if_true, if_false, fall_through);
   } else {
     if (if_false != fall_through) __ jmp(if_false);
@@ skipping 254 matching lines @@
   *context_length = 0;
   return previous_;
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64