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Port optimized comparison of a string to a constant single character string to X64 platform. Fix small mistake on ia32 platform.

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Review URL: http://codereview.chromium.org/1627014

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4398 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
whesse@chromium.org 2010-04-13 13:42:45 +00:00
parent 7bca61c11d
commit f720592ac3
2 changed files with 169 additions and 17 deletions
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21
src/ia32/codegen-ia32.cc
View File

@ -2432,7 +2432,8 @@ void CodeGenerator::Comparison(AstNode* node,
left_side_constant_null = left_side.handle()->IsNull();
left_side_constant_1_char_string =
(left_side.handle()->IsString() &&
(String::cast(*left_side.handle())->length() == 1));
String::cast(*left_side.handle())->length() == 1 &&
String::cast(*left_side.handle())->IsAsciiRepresentation());
}
bool right_side_constant_smi = false;
bool right_side_constant_null = false;
@ -2442,7 +2443,8 @@ void CodeGenerator::Comparison(AstNode* node,
right_side_constant_null = right_side.handle()->IsNull();
right_side_constant_1_char_string =
(right_side.handle()->IsString() &&
(String::cast(*right_side.handle())->length() == 1));
String::cast(*right_side.handle())->length() == 1 &&
String::cast(*right_side.handle())->IsAsciiRepresentation());
}
if (left_side_constant_smi || right_side_constant_smi) {
@ -2631,6 +2633,7 @@ void CodeGenerator::Comparison(AstNode* node,
JumpTarget is_not_string, is_string;
Register left_reg = left_side.reg();
Handle<Object> right_val = right_side.handle();
ASSERT(StringShape(String::cast(*right_val)).IsSymbol());
__ test(left_side.reg(), Immediate(kSmiTagMask));
is_not_string.Branch(zero, &left_side);
Result temp = allocator_->Allocate();
@ -2655,7 +2658,7 @@ void CodeGenerator::Comparison(AstNode* node,
dest->false_target()->Branch(not_equal);
__ bind(&not_a_symbol);
}
// If the receiver is not a string of the type we handle call the stub.
// Call the compare stub if the left side is not a flat ascii string.
__ and_(temp.reg(),
kIsNotStringMask | kStringRepresentationMask | kStringEncodingMask);
__ cmp(temp.reg(), kStringTag | kSeqStringTag | kAsciiStringTag);
@ -2673,7 +2676,7 @@ void CodeGenerator::Comparison(AstNode* node,
dest->false_target()->Jump();
is_string.Bind(&left_side);
// Here we know we have a sequential ASCII string.
// left_side is a sequential ASCII string.
left_side = Result(left_reg);
right_side = Result(right_val);
Result temp2 = allocator_->Allocate();
@ -2685,7 +2688,7 @@ void CodeGenerator::Comparison(AstNode* node,
Immediate(1));
__ j(not_equal, &comparison_done);
uint8_t char_value =
static_cast<uint8_t>(String::cast(*right_side.handle())->Get(0));
static_cast<uint8_t>(String::cast(*right_val)->Get(0));
__ cmpb(FieldOperand(left_side.reg(), SeqAsciiString::kHeaderSize),
char_value);
__ bind(&comparison_done);
@ -2694,17 +2697,17 @@ void CodeGenerator::Comparison(AstNode* node,
FieldOperand(left_side.reg(), String::kLengthOffset));
__ sub(Operand(temp2.reg()), Immediate(1));
Label comparison;
// If the length is 0 then our subtraction gave -1 which compares less
// If the length is 0 then the subtraction gave -1 which compares less
// than any character.
__ j(negative, &comparison);
// Otherwise load the first character.
__ movzx_b(temp2.reg(),
FieldOperand(left_side.reg(), SeqAsciiString::kHeaderSize));
__ bind(&comparison);
// Compare the first character of the string with out constant
// 1-character string.
// Compare the first character of the string with the
// constant 1-character string.
uint8_t char_value =
static_cast<uint8_t>(String::cast(*right_side.handle())->Get(0));
static_cast<uint8_t>(String::cast(*right_val)->Get(0));
__ cmp(Operand(temp2.reg()), Immediate(char_value));
Label characters_were_different;
__ j(not_equal, &characters_were_different);

165
src/x64/codegen-x64.cc
View File

@ -5241,14 +5241,28 @@ void CodeGenerator::Comparison(AstNode* node,
ASSERT(cc == less || cc == equal || cc == greater_equal);
// If either side is a constant smi, optimize the comparison.
bool left_side_constant_smi =
left_side.is_constant() && left_side.handle()->IsSmi();
bool right_side_constant_smi =
right_side.is_constant() && right_side.handle()->IsSmi();
bool left_side_constant_null =
left_side.is_constant() && left_side.handle()->IsNull();
bool right_side_constant_null =
right_side.is_constant() && right_side.handle()->IsNull();
bool left_side_constant_smi = false;
bool left_side_constant_null = false;
bool left_side_constant_1_char_string = false;
if (left_side.is_constant()) {
left_side_constant_smi = left_side.handle()->IsSmi();
left_side_constant_null = left_side.handle()->IsNull();
left_side_constant_1_char_string =
(left_side.handle()->IsString() &&
String::cast(*left_side.handle())->length() == 1 &&
String::cast(*left_side.handle())->IsAsciiRepresentation());
}
bool right_side_constant_smi = false;
bool right_side_constant_null = false;
bool right_side_constant_1_char_string = false;
if (right_side.is_constant()) {
right_side_constant_smi = right_side.handle()->IsSmi();
right_side_constant_null = right_side.handle()->IsNull();
right_side_constant_1_char_string =
(right_side.handle()->IsString() &&
String::cast(*right_side.handle())->length() == 1 &&
String::cast(*right_side.handle())->IsAsciiRepresentation());
}
if (left_side_constant_smi || right_side_constant_smi) {
if (left_side_constant_smi && right_side_constant_smi) {
@ -5388,6 +5402,141 @@ void CodeGenerator::Comparison(AstNode* node,
operand.Unuse();
dest->Split(not_zero);
}
} else if (left_side_constant_1_char_string ||
right_side_constant_1_char_string) {
if (left_side_constant_1_char_string && right_side_constant_1_char_string) {
// Trivial case, comparing two constants.
int left_value = String::cast(*left_side.handle())->Get(0);
int right_value = String::cast(*right_side.handle())->Get(0);
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 1 character string.
// If left side is a constant 1-character string, reverse the operands.
// Since one side is a constant string, conversion order does not matter.
if (left_side_constant_1_char_string) {
Result temp = left_side;
left_side = right_side;
right_side = temp;
cc = ReverseCondition(cc);
// This may reintroduce 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 string, inlining the case
// where both sides are strings.
left_side.ToRegister();
// 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_not_string, is_string;
Register left_reg = left_side.reg();
Handle<Object> right_val = right_side.handle();
ASSERT(StringShape(String::cast(*right_val)).IsSymbol());
Condition is_smi = masm()->CheckSmi(left_reg);
is_not_string.Branch(is_smi, &left_side);
Result temp = allocator_->Allocate();
ASSERT(temp.is_valid());
__ movq(temp.reg(),
FieldOperand(left_reg, HeapObject::kMapOffset));
__ movzxbl(temp.reg(),
FieldOperand(temp.reg(), Map::kInstanceTypeOffset));
// If we are testing for equality then make use of the symbol shortcut.
// Check if the left hand side has the same type as the right hand
// side (which is always a symbol).
if (cc == equal) {
Label not_a_symbol;
ASSERT(kSymbolTag != 0);
// Ensure that no non-strings have the symbol bit set.
ASSERT(kNotStringTag + kIsSymbolMask > LAST_TYPE);
__ testb(temp.reg(), Immediate(kIsSymbolMask)); // Test the symbol bit.
__ j(zero, &not_a_symbol);
// They are symbols, so do identity compare.
__ Cmp(left_reg, right_side.handle());
dest->true_target()->Branch(equal);
dest->false_target()->Branch(not_equal);
__ bind(&not_a_symbol);
}
// Call the compare stub if the left side is not a flat ascii string.
__ andb(temp.reg(),
Immediate(kIsNotStringMask |
kStringRepresentationMask |
kStringEncodingMask));
__ cmpb(temp.reg(),
Immediate(kStringTag | kSeqStringTag | kAsciiStringTag));
temp.Unuse();
is_string.Branch(equal, &left_side);
// Setup and call the compare stub.
is_not_string.Bind(&left_side);
CompareStub stub(cc, strict, kCantBothBeNaN);
Result result = frame_->CallStub(&stub, &left_side, &right_side);
result.ToRegister();
__ SmiCompare(result.reg(), Smi::FromInt(0));
result.Unuse();
dest->true_target()->Branch(cc);
dest->false_target()->Jump();
is_string.Bind(&left_side);
// left_side is a sequential ASCII string.
ASSERT(left_side.reg().is(left_reg));
right_side = Result(right_val);
Result temp2 = allocator_->Allocate();
ASSERT(temp2.is_valid());
// Test string equality and comparison.
if (cc == equal) {
Label comparison_done;
__ cmpl(FieldOperand(left_side.reg(), String::kLengthOffset),
Immediate(1));
__ j(not_equal, &comparison_done);
uint8_t char_value =
static_cast<uint8_t>(String::cast(*right_val)->Get(0));
__ cmpb(FieldOperand(left_side.reg(), SeqAsciiString::kHeaderSize),
Immediate(char_value));
__ bind(&comparison_done);
} else {
__ movl(temp2.reg(),
FieldOperand(left_side.reg(), String::kLengthOffset));
__ subl(temp2.reg(), Immediate(1));
Label comparison;
// If the length is 0 then the subtraction gave -1 which compares less
// than any character.
__ j(negative, &comparison);
// Otherwise load the first character.
__ movzxbl(temp2.reg(),
FieldOperand(left_side.reg(), SeqAsciiString::kHeaderSize));
__ bind(&comparison);
// Compare the first character of the string with the
// constant 1-character string.
uint8_t char_value =
static_cast<uint8_t>(String::cast(*right_side.handle())->Get(0));
__ cmpb(temp2.reg(), Immediate(char_value));
Label characters_were_different;
__ j(not_equal, &characters_were_different);
// If the first character is the same then the long string sorts after
// the short one.
__ cmpl(FieldOperand(left_side.reg(), String::kLengthOffset),
Immediate(1));
__ bind(&characters_were_different);
}
temp2.Unuse();
left_side.Unuse();
right_side.Unuse();
dest->Split(cc);
}
} else { // Neither side is a constant Smi or null.
// If either side is a non-smi constant, skip the smi check.
bool known_non_smi =