MIPS: Simplify StringCharCodeAt in non-crankshaft codegen.

Port r9936 (61034d).

BUG=
TEST=

Review URL: http://codereview.chromium.org/8506024
Patch from Gergely Kis <gergely@homejinni.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9947 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

diff --git a/src/arm/code-stubs-arm.cc b/src/arm/code-stubs-arm.cc
index 0d82682..6bf4d99 100644 (file)
--- a/src/arm/code-stubs-arm.cc
+++ b/src/arm/code-stubs-arm.cc
@@ -5103,7 +5103,7 @@ void StringCharCodeAtGenerator::GenerateFast(MacroAssembler* masm) {
   // Check that parent is not an external string. Go to runtime otherwise.
   // Note that if the original string is a cons or slice with an external
   // string as underlying string, we pass that unpacked underlying string with
-  // the updated index to the runtime function.
+  // the adjusted index to the runtime function.
   STATIC_ASSERT(kSeqStringTag == 0);
   __ tst(result_, Operand(kStringRepresentationMask));
   __ b(ne, &call_runtime_);

diff --git a/src/arm/lithium-codegen-arm.cc b/src/arm/lithium-codegen-arm.cc
index 880a34d..54526ed 100644 (file)
--- a/src/arm/lithium-codegen-arm.cc
+++ b/src/arm/lithium-codegen-arm.cc
@@ -3649,7 +3649,7 @@ void LCodeGen::DoStringCharCodeAt(LStringCharCodeAt* instr) {
   // shapes we support have just been unwrapped above.
   // Note that if the original string is a cons or slice with an external
   // string as underlying string, we pass that unpacked underlying string with
-  // the updated index to the runtime function.
+  // the adjusted index to the runtime function.
   __ bind(&check_sequential);
   STATIC_ASSERT(kSeqStringTag == 0);
   __ tst(result, Operand(kStringRepresentationMask));

diff --git a/src/ia32/code-stubs-ia32.cc b/src/ia32/code-stubs-ia32.cc
index 2b18af0..629f585 100644 (file)
--- a/src/ia32/code-stubs-ia32.cc
+++ b/src/ia32/code-stubs-ia32.cc
@@ -5146,7 +5146,7 @@ void StringCharCodeAtGenerator::GenerateFast(MacroAssembler* masm) {
   // Assure that we are dealing with a sequential string. Go to runtime if not.
   // Note that if the original string is a cons or slice with an external
   // string as underlying string, we pass that unpacked underlying string with
-  // the updated index to the runtime function.
+  // the adjusted index to the runtime function.
   __ bind(&assure_seq_string);
   __ mov(result_, FieldOperand(object_, HeapObject::kMapOffset));
   __ movzx_b(result_, FieldOperand(result_, Map::kInstanceTypeOffset));

diff --git a/src/ia32/lithium-codegen-ia32.cc b/src/ia32/lithium-codegen-ia32.cc
index 8eec9c4..0ec80e2 100644 (file)
--- a/src/ia32/lithium-codegen-ia32.cc
+++ b/src/ia32/lithium-codegen-ia32.cc
@@ -3453,7 +3453,7 @@ void LCodeGen::DoStringCharCodeAt(LStringCharCodeAt* instr) {
   // shapes we support have just been unwrapped above.
   // Note that if the original string is a cons or slice with an external
   // string as underlying string, we pass that unpacked underlying string with
-  // the updated index to the runtime function.
+  // the adjusted index to the runtime function.
   __ bind(&check_sequential);
   STATIC_ASSERT(kSeqStringTag == 0);
   __ test(result, Immediate(kStringRepresentationMask));

diff --git a/src/mips/code-stubs-mips.cc b/src/mips/code-stubs-mips.cc
index 5e0e238..b40ab16 100644 (file)
--- a/src/mips/code-stubs-mips.cc
+++ b/src/mips/code-stubs-mips.cc
@@ -5243,7 +5243,6 @@ void StringCharCodeAtGenerator::GenerateFast(MacroAssembler* masm) {
   Label got_char_code;
   Label sliced_string;
 
-  ASSERT(!t0.is(scratch_));
   ASSERT(!t0.is(index_));
   ASSERT(!t0.is(result_));
   ASSERT(!t0.is(object_));
@@ -5261,13 +5260,11 @@ void StringCharCodeAtGenerator::GenerateFast(MacroAssembler* masm) {
   // If the index is non-smi trigger the non-smi case.
   __ JumpIfNotSmi(index_, &index_not_smi_);
 
-  // Put smi-tagged index into scratch register.
-  __ mov(scratch_, index_);
   __ bind(&got_smi_index_);
 
   // Check for index out of range.
   __ lw(t0, FieldMemOperand(object_, String::kLengthOffset));
-  __ Branch(index_out_of_range_, ls, t0, Operand(scratch_));
+  __ Branch(index_out_of_range_, ls, t0, Operand(index_));
 
   // We need special handling for non-flat strings.
   STATIC_ASSERT(kSeqStringTag == 0);
@@ -5291,28 +5288,28 @@ void StringCharCodeAtGenerator::GenerateFast(MacroAssembler* masm) {
   __ LoadRoot(t0, Heap::kEmptyStringRootIndex);
   __ Branch(&call_runtime_, ne, result_, Operand(t0));
 
-  // Get the first of the two strings and load its instance type.
-  __ lw(result_, FieldMemOperand(object_, ConsString::kFirstOffset));
+  // Get the first of the two parts.
+  __ lw(object_, FieldMemOperand(object_, ConsString::kFirstOffset));
   __ jmp(&assure_seq_string);
 
   // SlicedString, unpack and add offset.
   __ bind(&sliced_string);
   __ lw(result_, FieldMemOperand(object_, SlicedString::kOffsetOffset));
-  __ addu(scratch_, scratch_, result_);
-  __ lw(result_, FieldMemOperand(object_, SlicedString::kParentOffset));
+  __ Addu(index_, index_, result_);
+  __ lw(object_, FieldMemOperand(object_, SlicedString::kParentOffset));
 
   // Assure that we are dealing with a sequential string. Go to runtime if not.
   __ bind(&assure_seq_string);
-  __ lw(result_, FieldMemOperand(result_, HeapObject::kMapOffset));
+  __ lw(result_, FieldMemOperand(object_, HeapObject::kMapOffset));
   __ lbu(result_, FieldMemOperand(result_, Map::kInstanceTypeOffset));
   // Check that parent is not an external string. Go to runtime otherwise.
+  // Note that if the original string is a cons or slice with an external
+  // string as underlying string, we pass that unpacked underlying string with
+  // the adjusted index to the runtime function.
   STATIC_ASSERT(kSeqStringTag == 0);
 
   __ And(t0, result_, Operand(kStringRepresentationMask));
   __ Branch(&call_runtime_, ne, t0, Operand(zero_reg));
-  // Actually fetch the parent string if it is confirmed to be sequential.
-  STATIC_ASSERT(SlicedString::kParentOffset == ConsString::kFirstOffset);
-  __ lw(object_, FieldMemOperand(object_, SlicedString::kParentOffset));
 
   // Check for 1-byte or 2-byte string.
   __ bind(&flat_string);
@@ -5326,18 +5323,18 @@ void StringCharCodeAtGenerator::GenerateFast(MacroAssembler* masm) {
   // add without shifting since the smi tag size is the log2 of the
   // number of bytes in a two-byte character.
   STATIC_ASSERT(kSmiTag == 0 && kSmiTagSize == 1 && kSmiShiftSize == 0);
-  __ Addu(scratch_, object_, Operand(scratch_));
-  __ lhu(result_, FieldMemOperand(scratch_, SeqTwoByteString::kHeaderSize));
+  __ Addu(index_, object_, Operand(index_));
+  __ lhu(result_, FieldMemOperand(index_, SeqTwoByteString::kHeaderSize));
   __ Branch(&got_char_code);
 
   // ASCII string.
   // Load the byte into the result register.
   __ bind(&ascii_string);
 
-  __ srl(t0, scratch_, kSmiTagSize);
-  __ Addu(scratch_, object_, t0);
+  __ srl(t0, index_, kSmiTagSize);
+  __ Addu(index_, object_, t0);
 
-  __ lbu(result_, FieldMemOperand(scratch_, SeqAsciiString::kHeaderSize));
+  __ lbu(result_, FieldMemOperand(index_, SeqAsciiString::kHeaderSize));
 
   __ bind(&got_char_code);
   __ sll(result_, result_, kSmiTagSize);
@@ -5354,13 +5351,13 @@ void StringCharCodeAtGenerator::GenerateSlow(
   __ bind(&index_not_smi_);
   // If index is a heap number, try converting it to an integer.
   __ CheckMap(index_,
-              scratch_,
+              result_,
               Heap::kHeapNumberMapRootIndex,
               index_not_number_,
               DONT_DO_SMI_CHECK);
   call_helper.BeforeCall(masm);
   // Consumed by runtime conversion function:
-  __ Push(object_, index_, index_);
+  __ Push(object_, index_);
   if (index_flags_ == STRING_INDEX_IS_NUMBER) {
     __ CallRuntime(Runtime::kNumberToIntegerMapMinusZero, 1);
   } else {
@@ -5372,16 +5369,14 @@ void StringCharCodeAtGenerator::GenerateSlow(
   // Save the conversion result before the pop instructions below
   // have a chance to overwrite it.
 
-  __ Move(scratch_, v0);
-
-  __ pop(index_);
+  __ Move(index_, v0);
   __ pop(object_);
   // Reload the instance type.
   __ lw(result_, FieldMemOperand(object_, HeapObject::kMapOffset));
   __ lbu(result_, FieldMemOperand(result_, Map::kInstanceTypeOffset));
   call_helper.AfterCall(masm);
   // If index is still not a smi, it must be out of range.
-  __ JumpIfNotSmi(scratch_, index_out_of_range_);
+  __ JumpIfNotSmi(index_, index_out_of_range_);
   // Otherwise, return to the fast path.
   __ Branch(&got_smi_index_);
 

diff --git a/src/mips/full-codegen-mips.cc b/src/mips/full-codegen-mips.cc
index 2c82bfa..555cad9 100644 (file)
--- a/src/mips/full-codegen-mips.cc
+++ b/src/mips/full-codegen-mips.cc
@@ -3058,7 +3058,6 @@ void FullCodeGenerator::EmitStringCharCodeAt(CallRuntime* expr) {
 
   Register object = a1;
   Register index = a0;
-  Register scratch = a2;
   Register result = v0;
 
   __ pop(object);
@@ -3068,7 +3067,6 @@ void FullCodeGenerator::EmitStringCharCodeAt(CallRuntime* expr) {
   Label done;
   StringCharCodeAtGenerator generator(object,
                                       index,
-                                      scratch,
                                       result,
                                       &need_conversion,
                                       &need_conversion,
@@ -3107,8 +3105,7 @@ void FullCodeGenerator::EmitStringCharAt(CallRuntime* expr) {
 
   Register object = a1;
   Register index = a0;
-  Register scratch1 = a2;
-  Register scratch2 = a3;
+  Register scratch = a3;
   Register result = v0;
 
   __ pop(object);
@@ -3118,8 +3115,7 @@ void FullCodeGenerator::EmitStringCharAt(CallRuntime* expr) {
   Label done;
   StringCharAtGenerator generator(object,
                                   index,
-                                  scratch1,
-                                  scratch2,
+                                  scratch,
                                   result,
                                   &need_conversion,
                                   &need_conversion,

diff --git a/src/mips/ic-mips.cc b/src/mips/ic-mips.cc
index a8b3fa3..b057695 100644 (file)
--- a/src/mips/ic-mips.cc
+++ b/src/mips/ic-mips.cc
@@ -1120,14 +1120,12 @@ void KeyedLoadIC::GenerateString(MacroAssembler* masm) {
 
   Register receiver = a1;
   Register index = a0;
-  Register scratch1 = a2;
-  Register scratch2 = a3;
+  Register scratch = a3;
   Register result = v0;
 
   StringCharAtGenerator char_at_generator(receiver,
                                           index,
-                                          scratch1,
-                                          scratch2,
+                                          scratch,
                                           result,
                                           &miss,  // When not a string.
                                           &miss,  // When not a number.

diff --git a/src/mips/lithium-codegen-mips.cc b/src/mips/lithium-codegen-mips.cc
index fee9dad..ca1d2b5 100644 (file)
--- a/src/mips/lithium-codegen-mips.cc
+++ b/src/mips/lithium-codegen-mips.cc
@@ -3569,6 +3569,9 @@ void LCodeGen::DoStringCharCodeAt(LStringCharCodeAt* instr) {
 
   // Check whether the string is sequential. The only non-sequential
   // shapes we support have just been unwrapped above.
+  // Note that if the original string is a cons or slice with an external
+  // string as underlying string, we pass that unpacked underlying string with
+  // the adjusted index to the runtime function.
   __ bind(&check_sequential);
   STATIC_ASSERT(kSeqStringTag == 0);
   __ And(temp, result, Operand(kStringRepresentationMask));

diff --git a/src/mips/stub-cache-mips.cc b/src/mips/stub-cache-mips.cc
index 2d60693..1cc8a97 100644 (file)
--- a/src/mips/stub-cache-mips.cc
+++ b/src/mips/stub-cache-mips.cc
@@ -1751,7 +1751,6 @@ Handle<Code> CallStubCompiler::CompileStringCharCodeAtCall(
 
   Register receiver = a1;
   Register index = t1;
-  Register scratch = a3;
   Register result = v0;
   __ lw(receiver, MemOperand(sp, argc * kPointerSize));
   if (argc > 0) {
@@ -1762,7 +1761,6 @@ Handle<Code> CallStubCompiler::CompileStringCharCodeAtCall(
 
   StringCharCodeAtGenerator generator(receiver,
                                       index,
-                                      scratch,
                                       result,
                                       &miss,  // When not a string.
                                       &miss,  // When not a number.
@@ -1833,8 +1831,7 @@ Handle<Code> CallStubCompiler::CompileStringCharAtCall(
 
   Register receiver = v0;
   Register index = t1;
-  Register scratch1 = a1;
-  Register scratch2 = a3;
+  Register scratch = a3;
   Register result = v0;
   __ lw(receiver, MemOperand(sp, argc * kPointerSize));
   if (argc > 0) {
@@ -1845,8 +1842,7 @@ Handle<Code> CallStubCompiler::CompileStringCharAtCall(
 
   StringCharAtGenerator generator(receiver,
                                   index,
-                                  scratch1,
-                                  scratch2,
+                                  scratch,
                                   result,
                                   &miss,  // When not a string.
                                   &miss,  // When not a number.

diff --git a/src/x64/code-stubs-x64.cc b/src/x64/code-stubs-x64.cc
index 3dcc110..cd269cb 100644 (file)
--- a/src/x64/code-stubs-x64.cc
+++ b/src/x64/code-stubs-x64.cc
@@ -4108,7 +4108,7 @@ void StringCharCodeAtGenerator::GenerateFast(MacroAssembler* masm) {
   // Assure that we are dealing with a sequential string. Go to runtime if not.
   // Note that if the original string is a cons or slice with an external
   // string as underlying string, we pass that unpacked underlying string with
-  // the updated index to the runtime function.
+  // the adjusted index to the runtime function.
   __ bind(&assure_seq_string);
   __ movq(result_, FieldOperand(object_, HeapObject::kMapOffset));
   __ movzxbl(result_, FieldOperand(result_, Map::kInstanceTypeOffset));

diff --git a/src/x64/lithium-codegen-x64.cc b/src/x64/lithium-codegen-x64.cc
index 3b71234..22d4c3d 100644 (file)
--- a/src/x64/lithium-codegen-x64.cc
+++ b/src/x64/lithium-codegen-x64.cc
@@ -3382,7 +3382,7 @@ void LCodeGen::DoStringCharCodeAt(LStringCharCodeAt* instr) {
   // shapes we support have just been unwrapped above.
   // Note that if the original string is a cons or slice with an external
   // string as underlying string, we pass that unpacked underlying string with
-  // the updated index to the runtime function.
+  // the adjusted index to the runtime function.
   __ bind(&check_sequential);
   STATIC_ASSERT(kSeqStringTag == 0);
   __ testb(result, Immediate(kStringRepresentationMask));