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LibJS/JIT: Add fast path for RightShift

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This commit is contained in:
iliadsh 2023-11-07 04:26:49 +00:00 • committed by Andreas Kling
parent 1244e91481
commit c956316c98
3 changed files with 55 additions and 1 deletions
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17
Userland/Libraries/LibJIT/X86_64/Assembler.h
View file

@ -583,6 +583,23 @@ struct X86_64Assembler {
}
}
void arithmetic_right_shift32(Operand dest, Optional<Operand> count)
{
VERIFY(dest.type == Operand::Type::Reg);
if (count.has_value()) {
VERIFY(count->type == Operand::Type::Imm);
VERIFY(count->fits_in_u8());
emit_rex_for_slash(dest, REX_W::No);
emit8(0xc1);
emit_modrm_slash(7, dest);
emit8(count->offset_or_immediate);
} else {
emit_rex_for_slash(dest, REX_W::No);
emit8(0xd3);
emit_modrm_slash(7, dest);
}
}
void enter()
{
push(Operand::Register(Reg::RBP));

38
Userland/Libraries/LibJS/JIT/Compiler.cpp
View file

@ -800,6 +800,44 @@ void Compiler::compile_left_shift(Bytecode::Op::LeftShift const& op)
end.link(m_assembler);
}
static Value cxx_right_shift(VM& vm, Value lhs, Value rhs)
{
return TRY_OR_SET_EXCEPTION(right_shift(vm, lhs, rhs));
}
void Compiler::compile_right_shift(Bytecode::Op::RightShift const& op)
{
load_vm_register(ARG1, op.lhs());
load_accumulator(ARG2);
Assembler::Label end {};
branch_if_both_int32(ARG1, ARG2, [&] {
// RCX = ARG2
m_assembler.mov(
Assembler::Operand::Register(Assembler::Reg::RCX),
Assembler::Operand::Register(ARG2));
// ARG1 >>= CL (32-bit)
m_assembler.arithmetic_right_shift32(Assembler::Operand::Register(ARG1), {});
// accumulator = ARG1 | SHIFTED_INT32_TAG;
m_assembler.mov(
Assembler::Operand::Register(GPR0),
Assembler::Operand::Imm(SHIFTED_INT32_TAG));
m_assembler.bitwise_or(
Assembler::Operand::Register(ARG1),
Assembler::Operand::Register(GPR0));
store_accumulator(ARG1);
m_assembler.jump(end);
});
native_call((void*)cxx_right_shift);
store_accumulator(RET);
check_exception();
end.link(m_assembler);
}
static ThrowCompletionOr<Value> not_(VM&, Value value)
{
return Value(!value.to_boolean());

1
Userland/Libraries/LibJS/JIT/Compiler.h
View file

@ -53,7 +53,6 @@ private:
O(LooselyEquals, abstract_equals) \
O(StrictlyInequals, typed_inequals) \
O(StrictlyEquals, typed_equals) \
O(RightShift, right_shift) \
O(UnsignedRightShift, unsigned_right_shift)
# define JS_ENUMERATE_NEW_BUILTIN_ERROR_BYTECODE_OPS(O) \