ES6 symbols: Implement Symbol intrinsic and basic functionality

src/arm/code-stubs-arm.cc

Index: src/arm/code-stubs-arm.cc
diff --git a/src/arm/code-stubs-arm.cc b/src/arm/code-stubs-arm.cc
index a6805e7b8029750f1dfdff376b3737517005651c..5368dd507a522b21c5f37128b0af44cfe8dac5fb 100644
--- a/src/arm/code-stubs-arm.cc
+++ b/src/arm/code-stubs-arm.cc
@@ -7099,6 +7099,57 @@ void ICCompareStub::GenerateInternalizedStrings(MacroAssembler* masm) {
 }
 
 
+void ICCompareStub::GenerateUniqueNames(MacroAssembler* masm) {
+  ASSERT(state_ == CompareIC::UNIQUE_NAME);
+  ASSERT(GetCondition() == eq);
+  Label miss;
+
+  // Registers containing left and right operands respectively.
+  Register left = r1;
+  Register right = r0;
+  Register tmp1 = r2;
+  Register tmp2 = r3;
+
+  // Check that both operands are heap objects.
+  __ JumpIfEitherSmi(left, right, &miss);
+
+  // Check that both operands are unique names. This leaves the instance
+  // types loaded in tmp1 and tmp2.
+  STATIC_ASSERT(kInternalizedTag != 0);
+  __ ldr(tmp1, FieldMemOperand(left, HeapObject::kMapOffset));
+  __ ldr(tmp2, FieldMemOperand(right, HeapObject::kMapOffset));
+  __ ldrb(tmp1, FieldMemOperand(tmp1, Map::kInstanceTypeOffset));
+  __ ldrb(tmp2, FieldMemOperand(tmp2, Map::kInstanceTypeOffset));
+
+  Label succeed1;
+  __ tst(tmp1, Operand(kIsInternalizedMask));
+  __ b(ne, &succeed1);
+  __ cmp(tmp1, Operand(SYMBOL_TYPE));
+  __ b(ne, &miss);
+  __ bind(&succeed1);
+
+  Label succeed2;
+  __ tst(tmp2, Operand(kIsInternalizedMask));
+  __ b(ne, &succeed2);
+  __ cmp(tmp2, Operand(SYMBOL_TYPE));
+  __ b(ne, &miss);
+  __ bind(&succeed2);
+
+  // Unique names are compared by identity.
+  __ cmp(left, right);
+  // Make sure r0 is non-zero. At this point input operands are
+  // guaranteed to be non-zero.
+  ASSERT(right.is(r0));
+  STATIC_ASSERT(EQUAL == 0);
+  STATIC_ASSERT(kSmiTag == 0);
+  __ mov(r0, Operand(Smi::FromInt(EQUAL)), LeaveCC, eq);
+  __ Ret();
+
+  __ bind(&miss);
+  GenerateMiss(masm);
+}
+
+
 void ICCompareStub::GenerateStrings(MacroAssembler* masm) {
   ASSERT(state_ == CompareIC::STRING);
   Label miss;