Compare IC: add STRINGS state.

BUG=1340

Review URL: http://codereview.chromium.org/6937001

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@7783 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/code-stubs-arm.cc

@@ -5903,6 +5903,71 @@ void ICCompareStub::GenerateHeapNumbers(MacroAssembler* masm) {
 }
 
 
+void ICCompareStub::GenerateStrings(MacroAssembler* masm) {
+  ASSERT(state_ == CompareIC::STRINGS);
+  Label miss;
+
+  // Registers containing left and right operands respectively.
+  Register left = r1;
+  Register right = r0;
+  Register tmp1 = r2;
+  Register tmp2 = r3;
+  Register tmp3 = r4;
+  Register tmp4 = r5;
+
+  // Check that both operands are heap objects.
+  __ JumpIfEitherSmi(left, right, &miss);
+
+  // Check that both operands are strings. This leaves the instance
+  // types loaded in tmp1 and tmp2.
+  __ ldr(tmp1, FieldMemOperand(left, HeapObject::kMapOffset));
+  __ ldr(tmp2, FieldMemOperand(right, HeapObject::kMapOffset));
+  __ ldrb(tmp1, FieldMemOperand(tmp1, Map::kInstanceTypeOffset));
+  __ ldrb(tmp2, FieldMemOperand(tmp2, Map::kInstanceTypeOffset));
+  STATIC_ASSERT(kNotStringTag != 0);
+  __ orr(tmp3, tmp1, tmp2);
+  __ tst(tmp3, Operand(kIsNotStringMask));
+  __ b(ne, &miss);
+
+  // Fast check for identical strings.
+  __ cmp(left, right);
+  STATIC_ASSERT(EQUAL == 0);
+  STATIC_ASSERT(kSmiTag == 0);
+  __ mov(r0, Operand(Smi::FromInt(EQUAL)), LeaveCC, eq);
+  __ Ret(eq);
+
+  // Handle not identical strings.
+
+  // Check that both strings are symbols. If they are, we're done
+  // because we already know they are not identical.
+  ASSERT(GetCondition() == eq);
+  STATIC_ASSERT(kSymbolTag != 0);
+  __ and_(tmp3, tmp1, Operand(tmp2));
+  __ tst(tmp3, Operand(kIsSymbolMask));
+  // Make sure r0 is non-zero. At this point input operands are
+  // guaranteed to be non-zero.
+  ASSERT(right.is(r0));
+  __ Ret(ne);
+
+  // Check that both strings are sequential ASCII.
+  Label runtime;
+  __ JumpIfBothInstanceTypesAreNotSequentialAscii(tmp1, tmp2, tmp3, tmp4,
+                                                  &runtime);
+
+  // Compare flat ASCII strings. Returns when done.
+  StringCompareStub::GenerateCompareFlatAsciiStrings(
+      masm, left, right, tmp1, tmp2, tmp3, tmp4);
+
+  // Handle more complex cases in runtime.
+  __ bind(&runtime);
+  __ Push(left, right);
+  __ TailCallRuntime(Runtime::kStringCompare, 2, 1);
+
+  __ bind(&miss);
+  GenerateMiss(masm);
+}
+
+
 void ICCompareStub::GenerateObjects(MacroAssembler* masm) {
   ASSERT(state_ == CompareIC::OBJECTS);
   Label miss;

src/code-stubs.cc

@@ -197,6 +197,9 @@ void ICCompareStub::Generate(MacroAssembler* masm) {
     case CompareIC::HEAP_NUMBERS:
       GenerateHeapNumbers(masm);
       break;
+    case CompareIC::STRINGS:
+      GenerateStrings(masm);
+      break;
     case CompareIC::OBJECTS:
       GenerateObjects(masm);
       break;

src/code-stubs.h

@@ -424,6 +424,7 @@ class ICCompareStub: public CodeStub {
 
   void GenerateSmis(MacroAssembler* masm);
   void GenerateHeapNumbers(MacroAssembler* masm);
+  void GenerateStrings(MacroAssembler* masm);
   void GenerateObjects(MacroAssembler* masm);
   void GenerateMiss(MacroAssembler* masm);
 

src/ia32/code-stubs-ia32.cc

@@ -5806,6 +5806,83 @@ void ICCompareStub::GenerateHeapNumbers(MacroAssembler* masm) {
 }
 
 
+void ICCompareStub::GenerateStrings(MacroAssembler* masm) {
+  ASSERT(state_ == CompareIC::STRINGS);
+  Label miss;
+
+  // Registers containing left and right operands respectively.
+  Register left = edx;
+  Register right = eax;
+  Register tmp1 = ecx;
+  Register tmp2 = ebx;
+  Register tmp3 = edi;
+
+  // Check that both operands are heap objects.
+  __ mov(tmp1, Operand(left));
+  STATIC_ASSERT(kSmiTag == 0);
+  __ and_(tmp1, Operand(right));
+  __ test(tmp1, Immediate(kSmiTagMask));
+  __ j(zero, &miss);
+
+  // Check that both operands are strings. This leaves the instance
+  // types loaded in tmp1 and tmp2.
+  __ mov(tmp1, FieldOperand(left, HeapObject::kMapOffset));
+  __ mov(tmp2, FieldOperand(right, HeapObject::kMapOffset));
+  __ movzx_b(tmp1, FieldOperand(tmp1, Map::kInstanceTypeOffset));
+  __ movzx_b(tmp2, FieldOperand(tmp2, Map::kInstanceTypeOffset));
+  __ mov(tmp3, tmp1);
+  STATIC_ASSERT(kNotStringTag != 0);
+  __ or_(tmp3, Operand(tmp2));
+  __ test(tmp3, Immediate(kIsNotStringMask));
+  __ j(not_zero, &miss);
+
+  // Fast check for identical strings.
+  NearLabel not_same;
+  __ cmp(left, Operand(right));
+  __ j(not_equal, &not_same);
+  STATIC_ASSERT(EQUAL == 0);
+  STATIC_ASSERT(kSmiTag == 0);
+  __ Set(eax, Immediate(Smi::FromInt(EQUAL)));
+  __ ret(0);
+
+  // Handle not identical strings.
+  __ bind(&not_same);
+
+  // Check that both strings are symbols. If they are, we're done
+  // because we already know they are not identical.
+  NearLabel do_compare;
+  ASSERT(GetCondition() == equal);
+  STATIC_ASSERT(kSymbolTag != 0);
+  __ and_(tmp1, Operand(tmp2));
+  __ test(tmp1, Immediate(kIsSymbolMask));
+  __ j(zero, &do_compare);
+  // Make sure eax is non-zero. At this point input operands are
+  // guaranteed to be non-zero.
+  ASSERT(right.is(eax));
+  __ ret(0);
+
+  // Check that both strings are sequential ASCII.
+  Label runtime;
+  __ bind(&do_compare);
+  __ JumpIfNotBothSequentialAsciiStrings(left, right, tmp1, tmp2, &runtime);
+
+  // Compare flat ASCII strings. Returns when done.
+  StringCompareStub::GenerateCompareFlatAsciiStrings(
+      masm, left, right, tmp1, tmp2, tmp3);
+
+  // Handle more complex cases in runtime.
+  __ bind(&runtime);
+  __ pop(tmp1);  // Return address.
+  __ push(left);
+  __ push(right);
+  __ push(tmp1);
+  __ TailCallRuntime(Runtime::kStringCompare, 2, 1);
+
+  __ bind(&miss);
+  GenerateMiss(masm);
+}
+
+
 void ICCompareStub::GenerateObjects(MacroAssembler* masm) {
   ASSERT(state_ == CompareIC::OBJECTS);
   NearLabel miss;

src/ic.cc

@@ -2141,6 +2141,7 @@ const char* CompareIC::GetStateName(State state) {
     case SMIS: return "SMIS";
     case HEAP_NUMBERS: return "HEAP_NUMBERS";
     case OBJECTS: return "OBJECTS";
+    case STRINGS: return "STRINGS";
     case GENERIC: return "GENERIC";
     default:
       UNREACHABLE();
@@ -2158,6 +2159,8 @@ CompareIC::State CompareIC::TargetState(State state,
   if ((state == UNINITIALIZED || (state == SMIS && has_inlined_smi_code)) &&
       x->IsNumber() && y->IsNumber()) return HEAP_NUMBERS;
   if (op_ != Token::EQ && op_ != Token::EQ_STRICT) return GENERIC;
+  if (state == UNINITIALIZED &&
+      x->IsString() && y->IsString()) return STRINGS;
   if (state == UNINITIALIZED &&
       x->IsJSObject() && y->IsJSObject()) return OBJECTS;
   return GENERIC;

src/ic.h

@@ -592,6 +592,7 @@ class CompareIC: public IC {
     UNINITIALIZED,
     SMIS,
     HEAP_NUMBERS,
+    STRINGS,
     OBJECTS,
     GENERIC
   };

src/x64/code-stubs-x64.cc

@@ -4685,6 +4685,81 @@ void ICCompareStub::GenerateHeapNumbers(MacroAssembler* masm) {
 }
 
 
+void ICCompareStub::GenerateStrings(MacroAssembler* masm) {
+  ASSERT(state_ == CompareIC::STRINGS);
+  Label miss;
+
+  // Registers containing left and right operands respectively.
+  Register left = rdx;
+  Register right = rax;
+  Register tmp1 = rcx;
+  Register tmp2 = rbx;
+  Register tmp3 = rdi;
+  Register tmp4 = r8;
+
+  // Check that both operands are heap objects.
+  Condition cond = masm->CheckEitherSmi(left, right, tmp1);
+  __ j(cond, &miss);
+
+  // Check that both operands are strings. This leaves the instance
+  // types loaded in tmp1 and tmp2.
+  __ movq(tmp1, FieldOperand(left, HeapObject::kMapOffset));
+  __ movq(tmp2, FieldOperand(right, HeapObject::kMapOffset));
+  __ movzxbq(tmp1, FieldOperand(tmp1, Map::kInstanceTypeOffset));
+  __ movzxbq(tmp2, FieldOperand(tmp2, Map::kInstanceTypeOffset));
+  __ movq(tmp3, tmp1);
+  STATIC_ASSERT(kNotStringTag != 0);
+  __ or_(tmp3, tmp2);
+  __ testl(tmp3, Immediate(kIsNotStringMask));
+  __ j(not_zero, &miss);
+
+  // Fast check for identical strings.
+  NearLabel not_same;
+  __ cmpq(left, right);
+  __ j(not_equal, &not_same);
+  STATIC_ASSERT(EQUAL == 0);
+  STATIC_ASSERT(kSmiTag == 0);
+  __ Move(rax, Smi::FromInt(EQUAL));
+  __ ret(0);
+
+  // Handle not identical strings.
+  __ bind(&not_same);
+
+  // Check that both strings are symbols. If they are, we're done
+  // because we already know they are not identical.
+  NearLabel do_compare;
+  ASSERT(GetCondition() == equal);
+  STATIC_ASSERT(kSymbolTag != 0);
+  __ and_(tmp1, tmp2);
+  __ testl(tmp1, Immediate(kIsSymbolMask));
+  __ j(zero, &do_compare);
+  // Make sure rax is non-zero. At this point input operands are
+  // guaranteed to be non-zero.
+  ASSERT(right.is(rax));
+  __ ret(0);
+
+  // Check that both strings are sequential ASCII.
+  Label runtime;
+  __ bind(&do_compare);
+  __ JumpIfNotBothSequentialAsciiStrings(left, right, tmp1, tmp2, &runtime);
+
+  // Compare flat ASCII strings. Returns when done.
+  StringCompareStub::GenerateCompareFlatAsciiStrings(
+      masm, left, right, tmp1, tmp2, tmp3, tmp4);
+
+  // Handle more complex cases in runtime.
+  __ bind(&runtime);
+  __ pop(tmp1);  // Return address.
+  __ push(left);
+  __ push(right);
+  __ push(tmp1);
+  __ TailCallRuntime(Runtime::kStringCompare, 2, 1);
+
+  __ bind(&miss);
+  GenerateMiss(masm);
+}
+
+
 void ICCompareStub::GenerateObjects(MacroAssembler* masm) {
   ASSERT(state_ == CompareIC::OBJECTS);
   NearLabel miss;