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Consistently make the bounds check for AccessArgumentsAt explicit.

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This has the advantage that AccessArgumentsAt itself can't deopt anymore and the
bounds check is visible for the elimination phase. Furthermore, things are
simply more consistent now, a good thing in itself. :-)

Review URL: https://codereview.chromium.org/11106012

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12721 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
svenpanne@chromium.org 2012-10-15 07:25:20 +00:00
parent 2389a514a0
commit 5a0176222b
9 changed files with 15 additions and 40 deletions
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6
src/arm/lithium-arm.cc
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@ -2164,12 +2164,10 @@ LInstruction* LChunkBuilder::DoArgumentsObject(HArgumentsObject* instr) {
LInstruction* LChunkBuilder::DoAccessArgumentsAt(HAccessArgumentsAt* instr) {
LOperand* arguments = UseRegister(instr->arguments());
LOperand* args = UseRegister(instr->arguments());
LOperand* length = UseTempRegister(instr->length());
LOperand* index = UseRegister(instr->index());
LAccessArgumentsAt* result =
new(zone()) LAccessArgumentsAt(arguments, length, index);
return AssignEnvironment(DefineAsRegister(result));
return DefineAsRegister(new(zone()) LAccessArgumentsAt(args, length, index));
}

7
src/arm/lithium-codegen-arm.cc
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@ -2904,14 +2904,9 @@ void LCodeGen::DoAccessArgumentsAt(LAccessArgumentsAt* instr) {
Register length = ToRegister(instr->length());
Register index = ToRegister(instr->index());
Register result = ToRegister(instr->result());
// Bailout index is not a valid argument index. Use unsigned check to get
// negative check for free.
__ sub(length, length, index, SetCC);
DeoptimizeIf(ls, instr->environment());
// There are two words between the frame pointer and the last argument.
// Subtracting from length accounts for one of them add one more.
__ sub(length, length, index);
__ add(length, length, Operand(1));
__ ldr(result, MemOperand(arguments, length, LSL, kPointerSizeLog2));
}

4
src/hydrogen.cc
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@ -9016,8 +9016,10 @@ void HGraphBuilder::GenerateArguments(CallRuntime* call) {
HInstruction* elements = AddInstruction(
new(zone()) HArgumentsElements(false));
HInstruction* length = AddInstruction(new(zone()) HArgumentsLength(elements));
HInstruction* checked_index =
AddInstruction(new(zone()) HBoundsCheck(index, length));
HAccessArgumentsAt* result =
new(zone()) HAccessArgumentsAt(elements, length, index);
new(zone()) HAccessArgumentsAt(elements, length, checked_index);
return ast_context()->ReturnInstruction(result, call->id());
}

5
src/ia32/lithium-codegen-ia32.cc
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@ -2742,12 +2742,9 @@ void LCodeGen::DoAccessArgumentsAt(LAccessArgumentsAt* instr) {
Register length = ToRegister(instr->length());
Operand index = ToOperand(instr->index());
Register result = ToRegister(instr->result());
__ sub(length, index);
DeoptimizeIf(below_equal, instr->environment());
// There are two words between the frame pointer and the last argument.
// Subtracting from length accounts for one of them add one more.
__ sub(length, index);
__ mov(result, Operand(arguments, length, times_4, kPointerSize));
}

6
src/ia32/lithium-ia32.cc
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@ -2279,12 +2279,10 @@ LInstruction* LChunkBuilder::DoArgumentsObject(HArgumentsObject* instr) {
LInstruction* LChunkBuilder::DoAccessArgumentsAt(HAccessArgumentsAt* instr) {
LOperand* arguments = UseRegister(instr->arguments());
LOperand* args = UseRegister(instr->arguments());
LOperand* length = UseTempRegister(instr->length());
LOperand* index = Use(instr->index());
LAccessArgumentsAt* result =
new(zone()) LAccessArgumentsAt(arguments, length, index);
return AssignEnvironment(DefineAsRegister(result));
return DefineAsRegister(new(zone()) LAccessArgumentsAt(args, length, index));
}

8
src/mips/lithium-codegen-mips.cc
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@ -2612,14 +2612,6 @@ void LCodeGen::DoAccessArgumentsAt(LAccessArgumentsAt* instr) {
Register length = ToRegister(instr->length());
Register index = ToRegister(instr->index());
Register result = ToRegister(instr->result());
// Bailout index is not a valid argument index. Use unsigned check to get
// negative check for free.
// TODO(plind): Shoud be optimized to do the sub before the DeoptimizeIf(),
// as they do in Arm. It will save us an instruction.
DeoptimizeIf(ls, instr->environment(), length, Operand(index));
// There are two words between the frame pointer and the last argument.
// Subtracting from length accounts for one of them, add one more.
__ subu(length, length, index);

6
src/mips/lithium-mips.cc
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@ -2106,12 +2106,10 @@ LInstruction* LChunkBuilder::DoArgumentsObject(HArgumentsObject* instr) {
LInstruction* LChunkBuilder::DoAccessArgumentsAt(HAccessArgumentsAt* instr) {
LOperand* arguments = UseRegister(instr->arguments());
LOperand* args = UseRegister(instr->arguments());
LOperand* length = UseTempRegister(instr->length());
LOperand* index = UseRegister(instr->index());
LAccessArgumentsAt* result =
new(zone()) LAccessArgumentsAt(arguments, length, index);
return AssignEnvironment(DefineAsRegister(result));
return DefineAsRegister(new(zone()) LAccessArgumentsAt(args, length, index));
}

7
src/x64/lithium-codegen-x64.cc
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@ -2601,16 +2601,13 @@ void LCodeGen::DoAccessArgumentsAt(LAccessArgumentsAt* instr) {
Register arguments = ToRegister(instr->arguments());
Register length = ToRegister(instr->length());
Register result = ToRegister(instr->result());
// There are two words between the frame pointer and the last argument.
// Subtracting from length accounts for one of them add one more.
if (instr->index()->IsRegister()) {
__ subl(length, ToRegister(instr->index()));
} else {
__ subl(length, ToOperand(instr->index()));
}
DeoptimizeIf(below_equal, instr->environment());
// There are two words between the frame pointer and the last argument.
// Subtracting from length accounts for one of them add one more.
__ movq(result, Operand(arguments, length, times_pointer_size, kPointerSize));
}

6
src/x64/lithium-x64.cc
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@ -2167,12 +2167,10 @@ LInstruction* LChunkBuilder::DoArgumentsObject(HArgumentsObject* instr) {
LInstruction* LChunkBuilder::DoAccessArgumentsAt(HAccessArgumentsAt* instr) {
LOperand* arguments = UseRegister(instr->arguments());
LOperand* args = UseRegister(instr->arguments());
LOperand* length = UseTempRegister(instr->length());
LOperand* index = Use(instr->index());
LAccessArgumentsAt* result =
new(zone()) LAccessArgumentsAt(arguments, length, index);
return AssignEnvironment(DefineAsRegister(result));
return DefineAsRegister(new(zone()) LAccessArgumentsAt(args, length, index));
}