2 use rustc::ty::{self, Ty, layout};
3 use syntax::ast::FloatTy;
4 use rustc::ty::layout::LayoutOf;
5 use rustc_apfloat::ieee::{Double, Single};
6 use rustc_apfloat::Float;
8 use super::{EvalContext, Place, Machine, ValTy};
10 use rustc::mir::interpret::{EvalResult, Scalar, Value};
12 impl<'a, 'mir, 'tcx, M: Machine<'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M> {
13 fn binop_with_overflow(
18 ) -> EvalResult<'tcx, (Scalar, bool)> {
19 let left_val = self.value_to_scalar(left)?;
20 let right_val = self.value_to_scalar(right)?;
21 self.binary_op(op, left_val, left.ty, right_val, right.ty)
24 /// Applies the binary operation `op` to the two operands and writes a tuple of the result
25 /// and a boolean signifying the potential overflow to the destination.
26 pub fn intrinsic_with_overflow(
33 ) -> EvalResult<'tcx> {
34 let (val, overflowed) = self.binop_with_overflow(op, left, right)?;
35 let val = Value::ScalarPair(val, Scalar::from_bool(overflowed));
40 self.write_value(valty, dest)
43 /// Applies the binary operation `op` to the arguments and writes the result to the
44 /// destination. Returns `true` if the operation overflowed.
45 pub fn intrinsic_overflowing(
52 ) -> EvalResult<'tcx, bool> {
53 let (val, overflowed) = self.binop_with_overflow(op, left, right)?;
54 self.write_scalar(dest, val, dest_ty)?;
59 impl<'a, 'mir, 'tcx, M: Machine<'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M> {
60 /// Returns the result of the specified operation and whether it overflowed.
68 ) -> EvalResult<'tcx, (Scalar, bool)> {
69 use rustc::mir::BinOp::*;
71 let left_layout = self.layout_of(left_ty)?;
72 let right_layout = self.layout_of(right_ty)?;
74 let left_kind = match left_layout.abi {
75 layout::Abi::Scalar(ref scalar) => scalar.value,
76 _ => return err!(TypeNotPrimitive(left_ty)),
78 let right_kind = match right_layout.abi {
79 layout::Abi::Scalar(ref scalar) => scalar.value,
80 _ => return err!(TypeNotPrimitive(right_ty)),
82 trace!("Running binary op {:?}: {:?} ({:?}), {:?} ({:?})", bin_op, left, left_kind, right, right_kind);
84 // I: Handle operations that support pointers
85 if !left_kind.is_float() && !right_kind.is_float() {
86 if let Some(handled) = M::try_ptr_op(self, bin_op, left, left_ty, right, right_ty)? {
91 // II: From now on, everything must be bytes, no pointers
92 let l = left.to_bits(left_layout.size)?;
93 let r = right.to_bits(right_layout.size)?;
95 // These ops can have an RHS with a different numeric type.
96 if right_kind.is_int() && (bin_op == Shl || bin_op == Shr) {
97 let signed = left_layout.abi.is_signed();
98 let mut oflo = (r as u32 as u128) != r;
100 let size = left_layout.size.bits() as u32;
105 let result = if signed {
106 let l = self.sign_extend(l, left_ty)? as i128;
107 let result = match bin_op {
110 _ => bug!("it has already been checked that this is a shift op"),
117 _ => bug!("it has already been checked that this is a shift op"),
120 let truncated = self.truncate(result, left_ty)?;
121 return Ok((Scalar::Bits {
127 if left_kind != right_kind {
129 "unimplemented binary op {:?}: {:?} ({:?}), {:?} ({:?})",
136 return err!(Unimplemented(msg));
139 if left_layout.abi.is_signed() {
140 let op: Option<fn(&i128, &i128) -> bool> = match bin_op {
141 Lt => Some(i128::lt),
142 Le => Some(i128::le),
143 Gt => Some(i128::gt),
144 Ge => Some(i128::ge),
147 if let Some(op) = op {
148 let l = self.sign_extend(l, left_ty)? as i128;
149 let r = self.sign_extend(r, right_ty)? as i128;
150 return Ok((Scalar::from_bool(op(&l, &r)), false));
152 let op: Option<fn(i128, i128) -> (i128, bool)> = match bin_op {
153 Div if r == 0 => return err!(DivisionByZero),
154 Rem if r == 0 => return err!(RemainderByZero),
155 Div => Some(i128::overflowing_div),
156 Rem => Some(i128::overflowing_rem),
157 Add => Some(i128::overflowing_add),
158 Sub => Some(i128::overflowing_sub),
159 Mul => Some(i128::overflowing_mul),
162 if let Some(op) = op {
163 let l128 = self.sign_extend(l, left_ty)? as i128;
164 let r = self.sign_extend(r, right_ty)? as i128;
165 let size = left_layout.size.bits();
169 if r == -1 && l == (1 << (size - 1)) {
170 return Ok((Scalar::Bits { bits: l, defined: size as u8 }, true));
175 trace!("{}, {}, {}", l, l128, r);
176 let (result, mut oflo) = op(l128, r);
177 trace!("{}, {}", result, oflo);
178 if !oflo && size != 128 {
179 let max = 1 << (size - 1);
180 oflo = result >= max || result < -max;
182 let result = result as u128;
183 let truncated = self.truncate(result, left_ty)?;
184 return Ok((Scalar::Bits {
191 if let ty::TyFloat(fty) = left_ty.sty {
192 macro_rules! float_math {
193 ($ty:path, $bitsize:expr) => {{
194 let l = <$ty>::from_bits(l);
195 let r = <$ty>::from_bits(r);
196 let bitify = |res: ::rustc_apfloat::StatusAnd<$ty>| Scalar::Bits {
197 bits: res.value.to_bits(),
200 let val = match bin_op {
201 Eq => Scalar::from_bool(l == r),
202 Ne => Scalar::from_bool(l != r),
203 Lt => Scalar::from_bool(l < r),
204 Le => Scalar::from_bool(l <= r),
205 Gt => Scalar::from_bool(l > r),
206 Ge => Scalar::from_bool(l >= r),
207 Add => bitify(l + r),
208 Sub => bitify(l - r),
209 Mul => bitify(l * r),
210 Div => bitify(l / r),
211 Rem => bitify(l % r),
212 _ => bug!("invalid float op: `{:?}`", bin_op),
214 return Ok((val, false));
218 FloatTy::F32 => float_math!(Single, 32),
219 FloatTy::F64 => float_math!(Double, 64),
223 let bit_width = self.layout_of(left_ty).unwrap().size.bits() as u8;
226 let val = match bin_op {
227 Eq => Scalar::from_bool(l == r),
228 Ne => Scalar::from_bool(l != r),
230 Lt => Scalar::from_bool(l < r),
231 Le => Scalar::from_bool(l <= r),
232 Gt => Scalar::from_bool(l > r),
233 Ge => Scalar::from_bool(l >= r),
235 BitOr => Scalar::Bits { bits: l | r, defined: bit_width },
236 BitAnd => Scalar::Bits { bits: l & r, defined: bit_width },
237 BitXor => Scalar::Bits { bits: l ^ r, defined: bit_width },
239 Add | Sub | Mul | Rem | Div => {
240 let op: fn(u128, u128) -> (u128, bool) = match bin_op {
241 Add => u128::overflowing_add,
242 Sub => u128::overflowing_sub,
243 Mul => u128::overflowing_mul,
244 Div if r == 0 => return err!(DivisionByZero),
245 Rem if r == 0 => return err!(RemainderByZero),
246 Div => u128::overflowing_div,
247 Rem => u128::overflowing_rem,
250 let (result, oflo) = op(l, r);
251 let truncated = self.truncate(result, left_ty)?;
252 return Ok((Scalar::Bits {
255 }, oflo || truncated != result));
260 "unimplemented binary op {:?}: {:?} ({:?}), {:?} ({:?})",
267 return err!(Unimplemented(msg));
279 ) -> EvalResult<'tcx, Scalar> {
280 use rustc::mir::UnOp::*;
281 use rustc_apfloat::ieee::{Single, Double};
282 use rustc_apfloat::Float;
284 let size = self.layout_of(ty)?.size;
285 let bytes = val.to_bits(size)?;
286 let size = size.bits();
288 let result_bytes = match (un_op, &ty.sty) {
290 (Not, ty::TyBool) => !val.to_bool()? as u128,
294 (Neg, ty::TyFloat(FloatTy::F32)) => Single::to_bits(-Single::from_bits(bytes)),
295 (Neg, ty::TyFloat(FloatTy::F64)) => Double::to_bits(-Double::from_bits(bytes)),
297 (Neg, _) if bytes == (1 << (size - 1)) => return err!(OverflowNeg),
298 (Neg, _) => (-(bytes as i128)) as u128,
302 bits: self.truncate(result_bytes, ty)?,