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use syntax::symbol::Symbol;
use rustc::ty;
use rustc::ty::layout::{LayoutOf, Primitive};
use rustc::mir::BinOp;
use rustc::mir::interpret::{
EvalResult, EvalErrorKind, Scalar,
};
use super::{
Machine, PlaceTy, OpTy, EvalContext,
};
fn numeric_intrinsic<'tcx>(
name: &str,
bits: u128,
kind: Primitive,
) -> EvalResult<'tcx, Scalar> {
let size = match kind {
Primitive::Int(integer, _) => integer.size(),
_ => bug!("invalid `{}` argument: {:?}", name, bits),
};
let extra = 128 - size.bits() as u128;
let bits_out = match name {
"ctpop" => bits.count_ones() as u128,
"ctlz" => bits.leading_zeros() as u128 - extra,
"cttz" => (bits << extra).trailing_zeros() as u128 - extra,
"bswap" => (bits << extra).swap_bytes(),
"bitreverse" => (bits << extra).reverse_bits(),
_ => bug!("not a numeric intrinsic: {}", name),
};
Ok(Scalar::from_uint(bits_out, size))
}
impl<'a, 'mir, 'tcx, M: Machine<'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M> {
pub fn emulate_intrinsic(
&mut self,
instance: ty::Instance<'tcx>,
args: &[OpTy<'tcx>],
dest: PlaceTy<'tcx>,
) -> EvalResult<'tcx, bool> {
let substs = instance.substs;
let intrinsic_name = &self.tcx.item_name(instance.def_id()).as_str()[..];
match intrinsic_name {
"min_align_of" => {
let elem_ty = substs.type_at(0);
let elem_align = self.layout_of(elem_ty)?.align.abi();
let align_val = Scalar::from_uint(elem_align, dest.layout.size);
self.write_scalar(align_val, dest)?;
}
"size_of" => {
let ty = substs.type_at(0);
let size = self.layout_of(ty)?.size.bytes() as u128;
let size_val = Scalar::from_uint(size, dest.layout.size);
self.write_scalar(size_val, dest)?;
}
"type_id" => {
let ty = substs.type_at(0);
let type_id = self.tcx.type_id_hash(ty) as u128;
let id_val = Scalar::from_uint(type_id, dest.layout.size);
self.write_scalar(id_val, dest)?;
}
| "ctpop"
| "cttz"
| "cttz_nonzero"
| "ctlz"
| "ctlz_nonzero"
| "bswap"
| "bitreverse" => {
let ty = substs.type_at(0);
let layout_of = self.layout_of(ty)?;
let bits = self.read_scalar(args[0])?.to_bits(layout_of.size)?;
let kind = match layout_of.abi {
ty::layout::Abi::Scalar(ref scalar) => scalar.value,
_ => Err(::rustc::mir::interpret::EvalErrorKind::TypeNotPrimitive(ty))?,
};
let out_val = if intrinsic_name.ends_with("_nonzero") {
if bits == 0 {
return err!(Intrinsic(format!("{} called on 0", intrinsic_name)));
}
numeric_intrinsic(intrinsic_name.trim_right_matches("_nonzero"), bits, kind)?
} else {
numeric_intrinsic(intrinsic_name, bits, kind)?
};
self.write_scalar(out_val, dest)?;
}
| "overflowing_add"
| "overflowing_sub"
| "overflowing_mul"
| "add_with_overflow"
| "sub_with_overflow"
| "mul_with_overflow" => {
let lhs = self.read_value(args[0])?;
let rhs = self.read_value(args[1])?;
let (bin_op, ignore_overflow) = match intrinsic_name {
"overflowing_add" => (BinOp::Add, true),
"overflowing_sub" => (BinOp::Sub, true),
"overflowing_mul" => (BinOp::Mul, true),
"add_with_overflow" => (BinOp::Add, false),
"sub_with_overflow" => (BinOp::Sub, false),
"mul_with_overflow" => (BinOp::Mul, false),
_ => bug!("Already checked for int ops")
};
if ignore_overflow {
self.binop_ignore_overflow(bin_op, lhs, rhs, dest)?;
} else {
self.binop_with_overflow(bin_op, lhs, rhs, dest)?;
}
}
"unchecked_shl" | "unchecked_shr" => {
let l = self.read_value(args[0])?;
let r = self.read_value(args[1])?;
let bin_op = match intrinsic_name {
"unchecked_shl" => BinOp::Shl,
"unchecked_shr" => BinOp::Shr,
_ => bug!("Already checked for int ops")
};
let (val, overflowed) = self.binary_op_val(bin_op, l, r)?;
if overflowed {
let layout = self.layout_of(substs.type_at(0))?;
let r_val = r.to_scalar()?.to_bits(layout.size)?;
return err!(Intrinsic(
format!("Overflowing shift by {} in {}", r_val, intrinsic_name),
));
}
self.write_scalar(val, dest)?;
}
"transmute" => {
let dest = self.force_allocation(dest)?;
self.copy_op(args[0], dest.into())?;
}
_ => return Ok(false),
}
Ok(true)
}
pub fn hook_fn(
&mut self,
instance: ty::Instance<'tcx>,
args: &[OpTy<'tcx>],
dest: Option<PlaceTy<'tcx>>,
) -> EvalResult<'tcx, bool> {
let def_id = instance.def_id();
if let Some((op, oflo)) = self.tcx.is_binop_lang_item(def_id) {
let dest = dest.expect("128 lowerings can't diverge");
let l = self.read_value(args[0])?;
let r = self.read_value(args[1])?;
if oflo {
self.binop_with_overflow(op, l, r, dest)?;
} else {
self.binop_ignore_overflow(op, l, r, dest)?;
}
return Ok(true);
} else if Some(def_id) == self.tcx.lang_items().panic_fn() {
assert!(args.len() == 1);
let ptr = self.read_value(args[0])?;
let place = self.ref_to_mplace(ptr)?;
let (msg, file, line, col) = (
self.mplace_field(place, 0)?,
self.mplace_field(place, 1)?,
self.mplace_field(place, 2)?,
self.mplace_field(place, 3)?,
);
let msg_place = self.ref_to_mplace(self.read_value(msg.into())?)?;
let msg = Symbol::intern(self.read_str(msg_place)?);
let file_place = self.ref_to_mplace(self.read_value(file.into())?)?;
let file = Symbol::intern(self.read_str(file_place)?);
let line = self.read_scalar(line.into())?.to_u32()?;
let col = self.read_scalar(col.into())?.to_u32()?;
return Err(EvalErrorKind::Panic { msg, file, line, col }.into());
} else if Some(def_id) == self.tcx.lang_items().begin_panic_fn() {
assert!(args.len() == 2);
let msg = args[0];
let ptr = self.read_value(args[1])?;
let place = self.ref_to_mplace(ptr)?;
let (file, line, col) = (
self.mplace_field(place, 0)?,
self.mplace_field(place, 1)?,
self.mplace_field(place, 2)?,
);
let msg_place = self.ref_to_mplace(self.read_value(msg.into())?)?;
let msg = Symbol::intern(self.read_str(msg_place)?);
let file_place = self.ref_to_mplace(self.read_value(file.into())?)?;
let file = Symbol::intern(self.read_str(file_place)?);
let line = self.read_scalar(line.into())?.to_u32()?;
let col = self.read_scalar(col.into())?.to_u32()?;
return Err(EvalErrorKind::Panic { msg, file, line, col }.into());
} else {
return Ok(false);
}
}
}