mirrors/ladybird
0
0
Fork 0
mirror of https://github.com/LadybirdBrowser/ladybird.git synced 2025-08-01 21:59:07 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 9

LibJS/Bytecode: Round constant operands of bitwise binary expressions

Browse source 
This helps some of the Cloudflare Turnstile stuff run faster, since they
are deliberately screwing with JS engines by asking us to do a bunch of
bitwise operations on e.g 65535.56

By rounding such values in bytecode generation, the interpreter can stay
on the happy path while executing, and finish quite a bit faster.
This commit is contained in:
Andreas Kling 2024-05-09 15:17:34 +02:00 • committed by Alexander Kalenik
commit 448f837d38
Notes: sideshowbarker 2024-07-18 02:47:59 +09:00
1 changed files with 52 additions and 2 deletions
Download patch file Download diff file Expand all files Collapse all files

54
Userland/Libraries/LibJS/Bytecode/ASTCodegen.cpp
View file

@ -90,9 +90,59 @@ Bytecode::CodeGenerationErrorOr<Optional<ScopedOperand>> BinaryExpression::gener
return dst;
}
auto lhs = TRY(m_lhs->generate_bytecode(generator)).value();
auto rhs = TRY(m_rhs->generate_bytecode(generator)).value();
// OPTIMIZATION: If LHS and/or RHS are numeric literals, we make sure they are converted to i32/u32
// as appropriate, to avoid having to perform these conversions at runtime.
auto get_left_side = [&](Expression const& side) -> CodeGenerationErrorOr<Optional<ScopedOperand>> {
switch (m_op) {
case BinaryOp::BitwiseAnd:
case BinaryOp::BitwiseOr:
case BinaryOp::BitwiseXor:
case BinaryOp::LeftShift:
case BinaryOp::RightShift:
case BinaryOp::UnsignedRightShift:
// LHS will always be converted to i32 for these ops.
if (side.is_numeric_literal()) {
auto value = MUST(static_cast<NumericLiteral const&>(side).value().to_i32(generator.vm()));
return generator.add_constant(Value(value));
}
break;
default:
break;
}
return side.generate_bytecode(generator);
};
auto get_right_side = [&](Expression const& side) -> CodeGenerationErrorOr<Optional<ScopedOperand>> {
switch (m_op) {
case BinaryOp::BitwiseAnd:
case BinaryOp::BitwiseOr:
case BinaryOp::BitwiseXor:
// RHS will always be converted to i32 for these ops.
if (side.is_numeric_literal()) {
auto value = MUST(static_cast<NumericLiteral const&>(side).value().to_i32(generator.vm()));
return generator.add_constant(Value(value));
}
break;
case BinaryOp::LeftShift:
case BinaryOp::RightShift:
case BinaryOp::UnsignedRightShift:
// RHS will always be converted to u32 for these ops.
if (side.is_numeric_literal()) {
auto value = MUST(static_cast<NumericLiteral const&>(side).value().to_u32(generator.vm()));
return generator.add_constant(Value(value));
}
break;
default:
break;
}
return side.generate_bytecode(generator);
};
auto lhs = TRY(get_left_side(*m_lhs)).value();
auto rhs = TRY(get_right_side(*m_rhs)).value();
auto dst = choose_dst(generator, preferred_dst);
switch (m_op) {
case BinaryOp::Addition: