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LibJS+LibJIT: Add fast path for Int32 - Int32

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This commit is contained in:
Andreas Kling 2023-11-03 08:35:07 +01:00
parent 56b4586d65
commit 17ae6edd8e
3 changed files with 67 additions and 1 deletions
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25
Userland/Libraries/LibJIT/Assembler.h
View file

@ -664,6 +664,31 @@ struct Assembler {
}
}
void sub32(Operand dst, Operand src, Optional<Label&> overflow_label)
{
if (dst.is_register_or_memory() && src.type == Operand::Type::Reg) {
emit_rex_for_mr(dst, src, REX_W::No);
emit8(0x29);
emit_modrm_mr(dst, src);
} else if (dst.is_register_or_memory() && src.type == Operand::Type::Imm && src.fits_in_i8()) {
emit_rex_for_slash(dst, REX_W::No);
emit8(0x83);
emit_modrm_slash(5, dst);
emit8(src.offset_or_immediate);
} else if (dst.is_register_or_memory() && src.type == Operand::Type::Imm && src.fits_in_i32()) {
emit_rex_for_slash(dst, REX_W::No);
emit8(0x81);
emit_modrm_slash(5, dst);
emit32(src.offset_or_immediate);
} else {
VERIFY_NOT_REACHED();
}
if (overflow_label.has_value()) {
jump_if(Condition::Overflow, *overflow_label);
}
}
// NOTE: It's up to the caller of this function to preserve registers as needed.
void native_call(void* callee, Vector<Operand> const& stack_arguments = {})
{

42
Userland/Libraries/LibJS/JIT/Compiler.cpp
View file

@ -536,6 +536,48 @@ void Compiler::compile_add(Bytecode::Op::Add const& op)
end.link(m_assembler);
}
static Value cxx_sub(VM& vm, Value lhs, Value rhs)
{
return TRY_OR_SET_EXCEPTION(sub(vm, lhs, rhs));
}
void Compiler::compile_sub(Bytecode::Op::Sub const& op)
{
load_vm_register(ARG1, op.lhs());
load_accumulator(ARG2);
Assembler::Label end {};
Assembler::Label slow_case {};
branch_if_both_int32(ARG1, ARG2, [&] {
// GPR0 = ARG1 + ARG2 (32-bit)
// if (overflow) goto slow_case;
m_assembler.mov(
Assembler::Operand::Register(GPR0),
Assembler::Operand::Register(ARG1));
m_assembler.sub32(
Assembler::Operand::Register(GPR0),
Assembler::Operand::Register(ARG2),
slow_case);
// accumulator = GPR0 | SHIFTED_INT32_TAG;
m_assembler.mov(
Assembler::Operand::Register(GPR1),
Assembler::Operand::Imm(SHIFTED_INT32_TAG));
m_assembler.bitwise_or(
Assembler::Operand::Register(GPR0),
Assembler::Operand::Register(GPR1));
store_accumulator(GPR0);
m_assembler.jump(end);
});
slow_case.link(m_assembler);
native_call((void*)cxx_sub);
store_accumulator(RET);
check_exception();
end.link(m_assembler);
}
static Value cxx_less_than(VM& vm, Value lhs, Value rhs)
{
return TRY_OR_SET_EXCEPTION(less_than(vm, lhs, rhs));

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

@ -41,7 +41,6 @@ private:
# endif
# define JS_ENUMERATE_COMMON_BINARY_OPS_WITHOUT_FAST_PATH(O) \
O(Sub, sub) \
O(Mul, mul) \
O(Div, div) \
O(Exp, exp) \