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mgretermgreter
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Optimize most common binary expression evaluation cases
By testing the most common cases first we can avoid the pretty expensive overhead for the more complex cases. This adds a bit of code overhead trading for better performance.
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2 files changed

+155
-26
lines changed

2 files changed

+155
-26
lines changed

‎src/eval.cpp

Lines changed: 152 additions & 26 deletions
Original file line numberDiff line numberDiff line change
@@ -52,7 +52,10 @@ namespace Sass {
5252
ctx(exp.ctx),
5353
force(false),
5454
is_in_comment(false)
55-
{ }
55+
{
56+
bool_true = SASS_MEMORY_NEW(Boolean, "[NA]", true);
57+
bool_false = SASS_MEMORY_NEW(Boolean, "[NA]", false);
58+
}
5659
Eval::~Eval() { }
5760

5861
Env* Eval::environment()
@@ -535,9 +538,138 @@ namespace Sass {
535538
Expression_Ptr Eval::operator()(Binary_Expression_Ptr b_in)
536539
{
537540

538-
String_Schema_Obj ret_schema;
541+
Expression_Obj lhs = b_in->left();
542+
Expression_Obj rhs = b_in->right();
543+
enum Sass_OP op_type = b_in->optype();
544+
545+
if (op_type == Sass_OP::AND) {
546+
// LOCAL_FLAG(force, true);
547+
lhs = lhs->perform(this);
548+
if (!*lhs) return lhs.detach();
549+
return rhs->perform(this);
550+
}
551+
else if (op_type == Sass_OP::OR) {
552+
// LOCAL_FLAG(force, true);
553+
lhs = lhs->perform(this);
554+
if (*lhs) return lhs.detach();
555+
return rhs->perform(this);
556+
}
557+
558+
// Evaluate variables as early o
559+
while (Variable_Ptr l_v = Cast<Variable>(lhs)) {
560+
lhs = operator()(l_v);
561+
}
562+
while (Variable_Ptr r_v = Cast<Variable>(rhs)) {
563+
rhs = operator()(r_v);
564+
}
565+
539566
Binary_Expression_Obj b = b_in;
540-
enum Sass_OP op_type = b->optype();
567+
568+
// Evaluate sub-expressions early on
569+
while (Binary_Expression_Ptr l_b = Cast<Binary_Expression>(lhs)) {
570+
if (!force && l_b->is_delayed()) break;
571+
lhs = operator()(l_b);
572+
}
573+
while (Binary_Expression_Ptr r_b = Cast<Binary_Expression>(rhs)) {
574+
if (!force && r_b->is_delayed()) break;
575+
rhs = operator()(r_b);
576+
}
577+
578+
// don't eval delayed expressions (the '/' when used as a separator)
579+
if (!force && op_type == Sass_OP::DIV && b->is_delayed()) {
580+
b->right(b->right()->perform(this));
581+
b->left(b->left()->perform(this));
582+
return b.detach();
583+
}
584+
585+
// specific types we know are final
586+
// handle them early to avoid overhead
587+
if (Number_Ptr l_n = Cast<Number>(lhs)) {
588+
// lhs is number and rhs is number
589+
if (Number_Ptr r_n = Cast<Number>(rhs)) {
590+
try {
591+
switch (op_type) {
592+
case Sass_OP::EQ: return *l_n == *r_n ? bool_true : bool_false;
593+
case Sass_OP::NEQ: return *l_n == *r_n ? bool_false : bool_true;
594+
case Sass_OP::LT: return *l_n < *r_n ? bool_true : bool_false;
595+
case Sass_OP::GTE: return *l_n < *r_n ? bool_false : bool_true;
596+
case Sass_OP::LTE: return *l_n < *r_n || *l_n == *r_n ? bool_true : bool_false;
597+
case Sass_OP::GT: return *l_n < *r_n || *l_n == *r_n ? bool_false : bool_true;
598+
case Sass_OP::ADD: case Sass_OP::SUB: case Sass_OP::MUL: case Sass_OP::DIV: case Sass_OP::MOD:
599+
return op_numbers(op_type, *l_n, *r_n, ctx.c_options, b_in->pstate());
600+
default: break;
601+
}
602+
}
603+
catch (Exception::OperationError& err)
604+
{
605+
throw Exception::SassValueError(b_in->pstate(), err);
606+
}
607+
}
608+
// lhs is number and rhs is color
609+
else if (Color_Ptr r_c = Cast<Color>(rhs)) {
610+
try {
611+
switch (op_type) {
612+
case Sass_OP::EQ: return *l_n == *r_c ? bool_true : bool_false;
613+
case Sass_OP::NEQ: return *l_n == *r_c ? bool_false : bool_true;
614+
case Sass_OP::LT: return *l_n < *r_c ? bool_true : bool_false;
615+
case Sass_OP::GTE: return *l_n < *r_c ? bool_false : bool_true;
616+
case Sass_OP::LTE: return *l_n < *r_c || *l_n == *r_c ? bool_true : bool_false;
617+
case Sass_OP::GT: return *l_n < *r_c || *l_n == *r_c ? bool_false : bool_true;
618+
case Sass_OP::ADD: case Sass_OP::SUB: case Sass_OP::MUL: case Sass_OP::DIV: case Sass_OP::MOD:
619+
return op_number_color(op_type, *l_n, *r_c, ctx.c_options, b_in->pstate());
620+
default: break;
621+
}
622+
}
623+
catch (Exception::OperationError& err)
624+
{
625+
throw Exception::SassValueError(b_in->pstate(), err);
626+
}
627+
}
628+
}
629+
else if (Color_Ptr l_c = Cast<Color>(lhs)) {
630+
// lhs is color and rhs is color
631+
if (Color_Ptr r_c = Cast<Color>(rhs)) {
632+
try {
633+
switch (op_type) {
634+
case Sass_OP::EQ: return *l_c == *r_c ? bool_true : bool_false;
635+
case Sass_OP::NEQ: return *l_c == *r_c ? bool_false : bool_true;
636+
case Sass_OP::LT: return *l_c < *r_c ? bool_true : bool_false;
637+
case Sass_OP::GTE: return *l_c < *r_c ? bool_false : bool_true;
638+
case Sass_OP::LTE: return *l_c < *r_c || *l_c == *r_c ? bool_true : bool_false;
639+
case Sass_OP::GT: return *l_c < *r_c || *l_c == *r_c ? bool_false : bool_true;
640+
case Sass_OP::ADD: case Sass_OP::SUB: case Sass_OP::MUL: case Sass_OP::DIV: case Sass_OP::MOD:
641+
return op_colors(op_type, *l_c, *r_c, ctx.c_options, b_in->pstate());
642+
default: break;
643+
}
644+
}
645+
catch (Exception::OperationError& err)
646+
{
647+
throw Exception::SassValueError(b_in->pstate(), err);
648+
}
649+
}
650+
// lhs is color and rhs is number
651+
else if (Number_Ptr r_n = Cast<Number>(rhs)) {
652+
try {
653+
switch (op_type) {
654+
case Sass_OP::EQ: return *l_c == *r_n ? bool_true : bool_false;
655+
case Sass_OP::NEQ: return *l_c == *r_n ? bool_false : bool_true;
656+
case Sass_OP::LT: return *l_c < *r_n ? bool_true : bool_false;
657+
case Sass_OP::GTE: return *l_c < *r_n ? bool_false : bool_true;
658+
case Sass_OP::LTE: return *l_c < *r_n || *l_c == *r_n ? bool_true : bool_false;
659+
case Sass_OP::GT: return *l_c < *r_n || *l_c == *r_n ? bool_false : bool_true;
660+
case Sass_OP::ADD: case Sass_OP::SUB: case Sass_OP::MUL: case Sass_OP::DIV: case Sass_OP::MOD:
661+
return op_color_number(op_type, *l_c, *r_n, ctx.c_options, b_in->pstate());
662+
default: break;
663+
}
664+
}
665+
catch (Exception::OperationError& err)
666+
{
667+
throw Exception::SassValueError(b_in->pstate(), err);
668+
}
669+
}
670+
}
671+
672+
String_Schema_Obj ret_schema;
541673

542674
// only the last item will be used to eval the binary expression
543675
if (String_Schema_Ptr s_l = Cast<String_Schema>(b->left())) {
@@ -568,16 +700,6 @@ namespace Sass {
568700
}
569701
}
570702

571-
// don't eval delayed expressions (the '/' when used as a separator)
572-
if (!force && op_type == Sass_OP::DIV && b->is_delayed()) {
573-
b->right(b->right()->perform(this));
574-
b->left(b->left()->perform(this));
575-
return b.detach();
576-
}
577-
578-
Expression_Obj lhs = b->left();
579-
Expression_Obj rhs = b->right();
580-
581703
// fully evaluate their values
582704
if (op_type == Sass_OP::EQ ||
583705
op_type == Sass_OP::NEQ ||
@@ -598,19 +720,6 @@ namespace Sass {
598720
lhs = lhs->perform(this);
599721
}
600722

601-
Binary_Expression_Obj u3 = b;
602-
switch (op_type) {
603-
case Sass_OP::AND: {
604-
return *lhs ? b->right()->perform(this) : lhs.detach();
605-
}
606-
607-
case Sass_OP::OR: {
608-
return *lhs ? lhs.detach() : b->right()->perform(this);
609-
}
610-
611-
default:
612-
break;
613-
}
614723
// not a logical connective, so go ahead and eval the rhs
615724
rhs = rhs->perform(this);
616725
AST_Node_Obj lu = lhs;
@@ -1385,6 +1494,23 @@ namespace Sass {
13851494
throw Exception::ZeroDivisionError(l, r);
13861495
}
13871496

1497+
size_t l_n_units = l.numerator_units().size();
1498+
size_t l_d_units = l.numerator_units().size();
1499+
size_t r_n_units = r.denominator_units().size();
1500+
size_t r_d_units = r.denominator_units().size();
1501+
// optimize out the most common and simplest case
1502+
if (l_n_units == r_n_units && l_d_units == r_d_units) {
1503+
if (l_n_units + l_d_units <= 1 && r_n_units + r_d_units <= 1) {
1504+
if (l.numerator_units() == r.numerator_units()) {
1505+
if (l.denominator_units() == r.denominator_units()) {
1506+
Number_Ptr v = SASS_MEMORY_COPY(&l);
1507+
v->value(ops[op](lv, rv));
1508+
return v;
1509+
}
1510+
}
1511+
}
1512+
}
1513+
13881514
Number tmp(&r); // copy
13891515
bool strict = op != Sass_OP::MUL && op != Sass_OP::DIV;
13901516
tmp.normalize(l.find_convertible_unit(), strict);

‎src/eval.hpp

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -26,6 +26,9 @@ namespace Sass {
2626
bool force;
2727
bool is_in_comment;
2828

29+
Boolean_Obj bool_true;
30+
Boolean_Obj bool_false;
31+
2932
Env* environment();
3033
Backtrace* backtrace();
3134
Selector_List_Obj selector();

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