Reviewers: jochen, ulan,
Message:
PTAL
Description:
A64: Relax the register constraints for LSeqStringGetChar.
[email protected], [email protected]
Please review this at https://codereview.chromium.org/197763006/
SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files (+14, -12 lines):
M src/a64/lithium-a64.cc
M src/a64/lithium-codegen-a64.cc
Index: src/a64/lithium-a64.cc
diff --git a/src/a64/lithium-a64.cc b/src/a64/lithium-a64.cc
index
ab76044546d887eb119058b1fb9ba668236c4ffc..6106efc7538217389948875d12c9e63d4d4c129a
100644
--- a/src/a64/lithium-a64.cc
+++ b/src/a64/lithium-a64.cc
@@ -2014,11 +2014,8 @@ LInstruction* LChunkBuilder::DoReturn(HReturn*
instr) {
LInstruction* LChunkBuilder::DoSeqStringGetChar(HSeqStringGetChar* instr) {
- // TODO(all): Use UseRegisterAtStart and UseRegisterOrConstantAtStart
here.
- // We cannot do it now because the debug code in the implementation
changes
- // temp.
- LOperand* string = UseRegister(instr->string());
- LOperand* index = UseRegisterOrConstant(instr->index());
+ LOperand* string = UseRegisterAtStart(instr->string());
+ LOperand* index = UseRegisterOrConstantAtStart(instr->index());
LOperand* temp = TempRegister();
LSeqStringGetChar* result =
new(zone()) LSeqStringGetChar(string, index, temp);
Index: src/a64/lithium-codegen-a64.cc
diff --git a/src/a64/lithium-codegen-a64.cc b/src/a64/lithium-codegen-a64.cc
index
4766fa55fd078d3ad2d902732094fec8dc38cc0e..ad0ccfe8153e51afeea0811c688d509214e867a6
100644
--- a/src/a64/lithium-codegen-a64.cc
+++ b/src/a64/lithium-codegen-a64.cc
@@ -4643,8 +4643,7 @@ MemOperand LCodeGen::BuildSeqStringOperand(Register
string,
STATIC_ASSERT(kCharSize == 1);
return FieldMemOperand(string, SeqString::kHeaderSize + offset);
}
- ASSERT(!temp.is(string));
- ASSERT(!temp.is(ToRegister(index)));
+
if (encoding == String::ONE_BYTE_ENCODING) {
__ Add(temp, string, Operand(ToRegister32(index), SXTW));
} else {
@@ -4662,15 +4661,21 @@ void
LCodeGen::DoSeqStringGetChar(LSeqStringGetChar* instr) {
Register temp = ToRegister(instr->temp());
if (FLAG_debug_code) {
- __ Ldr(temp, FieldMemOperand(string, HeapObject::kMapOffset));
- __ Ldrb(temp, FieldMemOperand(temp, Map::kInstanceTypeOffset));
+ // Even though this lithium instruction comes with a temp register, we
+ // can't use it here because we want to use "AtStart" constraints on
the
+ // inputs and the debug code here needs a scratch register.
+ UseScratchRegisterScope temps(masm());
+ Register dbg_temp = temps.AcquireX();
+
+ __ Ldr(dbg_temp, FieldMemOperand(string, HeapObject::kMapOffset));
+ __ Ldrb(dbg_temp, FieldMemOperand(dbg_temp, Map::kInstanceTypeOffset));
- __ And(temp, temp,
+ __ And(dbg_temp, dbg_temp,
Operand(kStringRepresentationMask | kStringEncodingMask));
static const uint32_t one_byte_seq_type = kSeqStringTag |
kOneByteStringTag;
static const uint32_t two_byte_seq_type = kSeqStringTag |
kTwoByteStringTag;
- __ Cmp(temp, Operand(encoding == String::ONE_BYTE_ENCODING
- ? one_byte_seq_type : two_byte_seq_type));
+ __ Cmp(dbg_temp, Operand(encoding == String::ONE_BYTE_ENCODING
+ ? one_byte_seq_type : two_byte_seq_type));
__ Check(eq, kUnexpectedStringType);
}
--
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