AuroraMiddleware/v8
1
0
Fork 0
Code Issues 2 Pull Requests Releases Wiki Activity

Avoid a smi check when comparing an unknown to a constant smi for equality on ia32 and x64 platforms.

Browse Source 
Review URL: http://codereview.chromium.org/2897013

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5077 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
whesse@chromium.org 2010-07-15 10:34:08 +00:00
parent ee1598ad90
commit dd06f4f102
4 changed files with 288 additions and 210 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

249
src/ia32/codegen-ia32.cc
View File

@ -2487,8 +2487,7 @@ void CodeGenerator::Comparison(AstNode* node,
}
ASSERT(cc == less || cc == equal || cc == greater_equal);
// If either side is a constant of some sort, we can probably optimize the
// comparison.
// If either side is a constant smi, optimize the comparison.
bool left_side_constant_smi = false;
bool left_side_constant_null = false;
bool left_side_constant_1_char_string = false;
@ -2513,114 +2512,11 @@ void CodeGenerator::Comparison(AstNode* node,
}
if (left_side_constant_smi || right_side_constant_smi) {
if (left_side_constant_smi && right_side_constant_smi) {
// Trivial case, comparing two constants.
int left_value = Smi::cast(*left_side.handle())->value();
int right_value = Smi::cast(*right_side.handle())->value();
switch (cc) {
case less:
dest->Goto(left_value < right_value);
break;
case equal:
dest->Goto(left_value == right_value);
break;
case greater_equal:
dest->Goto(left_value >= right_value);
break;
default:
UNREACHABLE();
}
} else {
// Only one side is a constant Smi.
// If left side is a constant Smi, reverse the operands.
// Since one side is a constant Smi, conversion order does not matter.
if (left_side_constant_smi) {
Result temp = left_side;
left_side = right_side;
right_side = temp;
cc = ReverseCondition(cc);
// This may re-introduce greater or less_equal as the value of cc.
// CompareStub and the inline code both support all values of cc.
}
// Implement comparison against a constant Smi, inlining the case
// where both sides are Smis.
left_side.ToRegister();
Register left_reg = left_side.reg();
Handle<Object> right_val = right_side.handle();
// Here we split control flow to the stub call and inlined cases
// before finally splitting it to the control destination. We use
// a jump target and branching to duplicate the virtual frame at
// the first split. We manually handle the off-frame references
// by reconstituting them on the non-fall-through path.
if (left_side.is_smi()) {
if (FLAG_debug_code) {
__ AbortIfNotSmi(left_side.reg());
}
} else {
JumpTarget is_smi;
__ test(left_side.reg(), Immediate(kSmiTagMask));
is_smi.Branch(zero, taken);
bool is_loop_condition = (node->AsExpression() != NULL) &&
node->AsExpression()->is_loop_condition();
if (!is_loop_condition &&
CpuFeatures::IsSupported(SSE2) &&
right_val->IsSmi()) {
// Right side is a constant smi and left side has been checked
// not to be a smi.
CpuFeatures::Scope use_sse2(SSE2);
JumpTarget not_number;
__ cmp(FieldOperand(left_reg, HeapObject::kMapOffset),
Immediate(Factory::heap_number_map()));
not_number.Branch(not_equal, &left_side);
__ movdbl(xmm1,
FieldOperand(left_reg, HeapNumber::kValueOffset));
int value = Smi::cast(*right_val)->value();
if (value == 0) {
__ xorpd(xmm0, xmm0);
} else {
Result temp = allocator()->Allocate();
__ mov(temp.reg(), Immediate(value));
__ cvtsi2sd(xmm0, Operand(temp.reg()));
temp.Unuse();
}
__ ucomisd(xmm1, xmm0);
// Jump to builtin for NaN.
not_number.Branch(parity_even, &left_side);
left_side.Unuse();
dest->true_target()->Branch(DoubleCondition(cc));
dest->false_target()->Jump();
not_number.Bind(&left_side);
}
// Setup and call the compare stub.
CompareStub stub(cc, strict, kCantBothBeNaN);
Result result = frame_->CallStub(&stub, &left_side, &right_side);
result.ToRegister();
__ cmp(result.reg(), 0);
result.Unuse();
dest->true_target()->Branch(cc);
dest->false_target()->Jump();
is_smi.Bind();
}
left_side = Result(left_reg);
right_side = Result(right_val);
// Test smi equality and comparison by signed int comparison.
if (IsUnsafeSmi(right_side.handle())) {
right_side.ToRegister();
__ cmp(left_side.reg(), Operand(right_side.reg()));
} else {
__ cmp(Operand(left_side.reg()), Immediate(right_side.handle()));
}
left_side.Unuse();
right_side.Unuse();
dest->Split(cc);
}
bool is_loop_condition = (node->AsExpression() != NULL) &&
node->AsExpression()->is_loop_condition();
ConstantSmiComparison(cc, strict, dest, &left_side, &right_side,
left_side_constant_smi, right_side_constant_smi,
is_loop_condition);
} else if (cc == equal &&
(left_side_constant_null || right_side_constant_null)) {
// To make null checks efficient, we check if either the left side or
@ -2882,6 +2778,139 @@ void CodeGenerator::Comparison(AstNode* node,
}
void CodeGenerator::ConstantSmiComparison(Condition cc,
bool strict,
ControlDestination* dest,
Result* left_side,
Result* right_side,
bool left_side_constant_smi,
bool right_side_constant_smi,
bool is_loop_condition) {
if (left_side_constant_smi && right_side_constant_smi) {
// Trivial case, comparing two constants.
int left_value = Smi::cast(*left_side->handle())->value();
int right_value = Smi::cast(*right_side->handle())->value();
switch (cc) {
case less:
dest->Goto(left_value < right_value);
break;
case equal:
dest->Goto(left_value == right_value);
break;
case greater_equal:
dest->Goto(left_value >= right_value);
break;
default:
UNREACHABLE();
}
} else {
// Only one side is a constant Smi.
// If left side is a constant Smi, reverse the operands.
// Since one side is a constant Smi, conversion order does not matter.
if (left_side_constant_smi) {
Result* temp = left_side;
left_side = right_side;
right_side = temp;
cc = ReverseCondition(cc);
// This may re-introduce greater or less_equal as the value of cc.
// CompareStub and the inline code both support all values of cc.
}
// Implement comparison against a constant Smi, inlining the case
// where both sides are Smis.
left_side->ToRegister();
Register left_reg = left_side->reg();
Handle<Object> right_val = right_side->handle();
if (left_side->is_smi()) {
if (FLAG_debug_code) {
__ AbortIfNotSmi(left_reg);
}
// Test smi equality and comparison by signed int comparison.
if (IsUnsafeSmi(right_side->handle())) {
right_side->ToRegister();
__ cmp(left_reg, Operand(right_side->reg()));
} else {
__ cmp(Operand(left_reg), Immediate(right_side->handle()));
}
left_side->Unuse();
right_side->Unuse();
dest->Split(cc);
} else {
// Only the case where the left side could possibly be a non-smi is left.
JumpTarget is_smi;
if (cc == equal) {
// We can do the equality comparison before the smi check.
__ cmp(Operand(left_reg), Immediate(right_side->handle()));
dest->true_target()->Branch(equal);
__ test(left_reg, Immediate(kSmiTagMask));
dest->false_target()->Branch(zero);
} else {
// Do the smi check, then the comparison.
JumpTarget is_not_smi;
__ test(left_reg, Immediate(kSmiTagMask));
is_smi.Branch(zero, left_side, right_side);
}
// Jump or fall through to here if we are comparing a non-smi to a
// constant smi. If the non-smi is a heap number and this is not
// a loop condition, inline the floating point code.
if (!is_loop_condition && CpuFeatures::IsSupported(SSE2)) {
// Right side is a constant smi and left side has been checked
// not to be a smi.
CpuFeatures::Scope use_sse2(SSE2);
JumpTarget not_number;
__ cmp(FieldOperand(left_reg, HeapObject::kMapOffset),
Immediate(Factory::heap_number_map()));
not_number.Branch(not_equal, left_side);
__ movdbl(xmm1,
FieldOperand(left_reg, HeapNumber::kValueOffset));
int value = Smi::cast(*right_val)->value();
if (value == 0) {
__ xorpd(xmm0, xmm0);
} else {
Result temp = allocator()->Allocate();
__ mov(temp.reg(), Immediate(value));
__ cvtsi2sd(xmm0, Operand(temp.reg()));
temp.Unuse();
}
__ ucomisd(xmm1, xmm0);
// Jump to builtin for NaN.
not_number.Branch(parity_even, left_side);
left_side->Unuse();
dest->true_target()->Branch(DoubleCondition(cc));
dest->false_target()->Jump();
not_number.Bind(left_side);
}
// Setup and call the compare stub.
CompareStub stub(cc, strict, kCantBothBeNaN);
Result result = frame_->CallStub(&stub, left_side, right_side);
result.ToRegister();
__ test(result.reg(), Operand(result.reg()));
result.Unuse();
if (cc == equal) {
dest->Split(cc);
} else {
dest->true_target()->Branch(cc);
dest->false_target()->Jump();
// It is important for performance for this case to be at the end.
is_smi.Bind(left_side, right_side);
if (IsUnsafeSmi(right_side->handle())) {
right_side->ToRegister();
__ cmp(left_reg, Operand(right_side->reg()));
} else {
__ cmp(Operand(left_reg), Immediate(right_side->handle()));
}
left_side->Unuse();
right_side->Unuse();
dest->Split(cc);
}
}
}
}
// Check that the comparison operand is a number. Jump to not_numbers jump
// target passing the left and right result if the operand is not a number.
static void CheckComparisonOperand(MacroAssembler* masm_,

11
src/ia32/codegen-ia32.h
View File

@ -560,6 +560,17 @@ class CodeGenerator: public AstVisitor {
Condition cc,
bool strict,
ControlDestination* destination);
// If at least one of the sides is a constant smi, generate optimized code.
void ConstantSmiComparison(Condition cc,
bool strict,
ControlDestination* destination,
Result* left_side,
Result* right_side,
bool left_side_constant_smi,
bool right_side_constant_smi,
bool is_loop_condition);
void GenerateInlineNumberComparison(Result* left_side,
Result* right_side,
Condition cc,

227
src/x64/codegen-x64.cc
View File

@ -2002,106 +2002,11 @@ void CodeGenerator::Comparison(AstNode* node,
}
if (left_side_constant_smi || right_side_constant_smi) {
if (left_side_constant_smi && right_side_constant_smi) {
// Trivial case, comparing two constants.
int left_value = Smi::cast(*left_side.handle())->value();
int right_value = Smi::cast(*right_side.handle())->value();
switch (cc) {
case less:
dest->Goto(left_value < right_value);
break;
case equal:
dest->Goto(left_value == right_value);
break;
case greater_equal:
dest->Goto(left_value >= right_value);
break;
default:
UNREACHABLE();
}
} else {
// Only one side is a constant Smi.
// If left side is a constant Smi, reverse the operands.
// Since one side is a constant Smi, conversion order does not matter.
if (left_side_constant_smi) {
Result temp = left_side;
left_side = right_side;
right_side = temp;
cc = ReverseCondition(cc);
// This may re-introduce greater or less_equal as the value of cc.
// CompareStub and the inline code both support all values of cc.
}
// Implement comparison against a constant Smi, inlining the case
// where both sides are Smis.
left_side.ToRegister();
Register left_reg = left_side.reg();
Handle<Object> right_val = right_side.handle();
// Here we split control flow to the stub call and inlined cases
// before finally splitting it to the control destination. We use
// a jump target and branching to duplicate the virtual frame at
// the first split. We manually handle the off-frame references
// by reconstituting them on the non-fall-through path.
JumpTarget is_smi;
if (left_side.is_smi()) {
if (FLAG_debug_code) {
__ AbortIfNotSmi(left_side.reg());
}
} else {
Condition left_is_smi = masm_->CheckSmi(left_side.reg());
is_smi.Branch(left_is_smi);
bool is_loop_condition = (node->AsExpression() != NULL) &&
node->AsExpression()->is_loop_condition();
if (!is_loop_condition && right_val->IsSmi()) {
// Right side is a constant smi and left side has been checked
// not to be a smi.
JumpTarget not_number;
__ Cmp(FieldOperand(left_reg, HeapObject::kMapOffset),
Factory::heap_number_map());
not_number.Branch(not_equal, &left_side);
__ movsd(xmm1,
FieldOperand(left_reg, HeapNumber::kValueOffset));
int value = Smi::cast(*right_val)->value();
if (value == 0) {
__ xorpd(xmm0, xmm0);
} else {
Result temp = allocator()->Allocate();
__ movl(temp.reg(), Immediate(value));
__ cvtlsi2sd(xmm0, temp.reg());
temp.Unuse();
}
__ ucomisd(xmm1, xmm0);
// Jump to builtin for NaN.
not_number.Branch(parity_even, &left_side);
left_side.Unuse();
dest->true_target()->Branch(DoubleCondition(cc));
dest->false_target()->Jump();
not_number.Bind(&left_side);
}
// Setup and call the compare stub.
CompareStub stub(cc, strict, kCantBothBeNaN);
Result result = frame_->CallStub(&stub, &left_side, &right_side);
result.ToRegister();
__ testq(result.reg(), result.reg());
result.Unuse();
dest->true_target()->Branch(cc);
dest->false_target()->Jump();
is_smi.Bind();
}
left_side = Result(left_reg);
right_side = Result(right_val);
// Test smi equality and comparison by signed int comparison.
// Both sides are smis, so we can use an Immediate.
__ SmiCompare(left_side.reg(), Smi::cast(*right_side.handle()));
left_side.Unuse();
right_side.Unuse();
dest->Split(cc);
}
bool is_loop_condition = (node->AsExpression() != NULL) &&
node->AsExpression()->is_loop_condition();
ConstantSmiComparison(cc, strict, dest, &left_side, &right_side,
left_side_constant_smi, right_side_constant_smi,
is_loop_condition);
} else if (cc == equal &&
(left_side_constant_null || right_side_constant_null)) {
// To make null checks efficient, we check if either the left side or
@ -2366,6 +2271,128 @@ void CodeGenerator::Comparison(AstNode* node,
}
void CodeGenerator::ConstantSmiComparison(Condition cc,
bool strict,
ControlDestination* dest,
Result* left_side,
Result* right_side,
bool left_side_constant_smi,
bool right_side_constant_smi,
bool is_loop_condition) {
if (left_side_constant_smi && right_side_constant_smi) {
// Trivial case, comparing two constants.
int left_value = Smi::cast(*left_side->handle())->value();
int right_value = Smi::cast(*right_side->handle())->value();
switch (cc) {
case less:
dest->Goto(left_value < right_value);
break;
case equal:
dest->Goto(left_value == right_value);
break;
case greater_equal:
dest->Goto(left_value >= right_value);
break;
default:
UNREACHABLE();
}
} else {
// Only one side is a constant Smi.
// If left side is a constant Smi, reverse the operands.
// Since one side is a constant Smi, conversion order does not matter.
if (left_side_constant_smi) {
Result* temp = left_side;
left_side = right_side;
right_side = temp;
cc = ReverseCondition(cc);
// This may re-introduce greater or less_equal as the value of cc.
// CompareStub and the inline code both support all values of cc.
}
// Implement comparison against a constant Smi, inlining the case
// where both sides are Smis.
left_side->ToRegister();
Register left_reg = left_side->reg();
Smi* constant_smi = Smi::cast(*right_side->handle());
if (left_side->is_smi()) {
if (FLAG_debug_code) {
__ AbortIfNotSmi(left_reg);
}
// Test smi equality and comparison by signed int comparison.
// Both sides are smis, so we can use an Immediate.
__ SmiCompare(left_reg, constant_smi);
left_side->Unuse();
right_side->Unuse();
dest->Split(cc);
} else {
// Only the case where the left side could possibly be a non-smi is left.
JumpTarget is_smi;
if (cc == equal) {
// We can do the equality comparison before the smi check.
__ SmiCompare(left_reg, constant_smi);
dest->true_target()->Branch(equal);
Condition left_is_smi = masm_->CheckSmi(left_reg);
dest->false_target()->Branch(left_is_smi);
} else {
// Do the smi check, then the comparison.
Condition left_is_smi = masm_->CheckSmi(left_reg);
is_smi.Branch(left_is_smi, left_side, right_side);
}
// Jump or fall through to here if we are comparing a non-smi to a
// constant smi. If the non-smi is a heap number and this is not
// a loop condition, inline the floating point code.
if (!is_loop_condition) {
// Right side is a constant smi and left side has been checked
// not to be a smi.
JumpTarget not_number;
__ Cmp(FieldOperand(left_reg, HeapObject::kMapOffset),
Factory::heap_number_map());
not_number.Branch(not_equal, left_side);
__ movsd(xmm1,
FieldOperand(left_reg, HeapNumber::kValueOffset));
int value = constant_smi->value();
if (value == 0) {
__ xorpd(xmm0, xmm0);
} else {
Result temp = allocator()->Allocate();
__ movl(temp.reg(), Immediate(value));
__ cvtlsi2sd(xmm0, temp.reg());
temp.Unuse();
}
__ ucomisd(xmm1, xmm0);
// Jump to builtin for NaN.
not_number.Branch(parity_even, left_side);
left_side->Unuse();
dest->true_target()->Branch(DoubleCondition(cc));
dest->false_target()->Jump();
not_number.Bind(left_side);
}
// Setup and call the compare stub.
CompareStub stub(cc, strict, kCantBothBeNaN);
Result result = frame_->CallStub(&stub, left_side, right_side);
result.ToRegister();
__ testq(result.reg(), result.reg());
result.Unuse();
if (cc == equal) {
dest->Split(cc);
} else {
dest->true_target()->Branch(cc);
dest->false_target()->Jump();
// It is important for performance for this case to be at the end.
is_smi.Bind(left_side, right_side);
__ SmiCompare(left_reg, constant_smi);
left_side->Unuse();
right_side->Unuse();
dest->Split(cc);
}
}
}
}
// Load a comparison operand into into a XMM register. Jump to not_numbers jump
// target passing the left and right result if the operand is not a number.
static void LoadComparisonOperand(MacroAssembler* masm_,

11
src/x64/codegen-x64.h
View File

@ -521,6 +521,17 @@ class CodeGenerator: public AstVisitor {
Condition cc,
bool strict,
ControlDestination* destination);
// If at least one of the sides is a constant smi, generate optimized code.
void ConstantSmiComparison(Condition cc,
bool strict,
ControlDestination* destination,
Result* left_side,
Result* right_side,
bool left_side_constant_smi,
bool right_side_constant_smi,
bool is_loop_condition);
void GenerateInlineNumberComparison(Result* left_side,
Result* right_side,
Condition cc,