1 use std::convert::TryFrom;
3 use rustc_apfloat::Float;
5 use rustc_middle::mir::interpret::{InterpResult, Scalar};
6 use rustc_middle::ty::layout::{LayoutOf, TyAndLayout};
7 use rustc_middle::ty::{self, FloatTy, Ty};
9 use super::{ImmTy, Immediate, InterpCx, Machine, PlaceTy};
11 impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
12 /// Applies the binary operation `op` to the two operands and writes a tuple of the result
13 /// and a boolean signifying the potential overflow to the destination.
14 pub fn binop_with_overflow(
17 left: &ImmTy<'tcx, M::PointerTag>,
18 right: &ImmTy<'tcx, M::PointerTag>,
19 dest: &PlaceTy<'tcx, M::PointerTag>,
20 ) -> InterpResult<'tcx> {
21 let (val, overflowed, ty) = self.overflowing_binary_op(op, &left, &right)?;
23 self.tcx.intern_tup(&[ty, self.tcx.types.bool]),
25 "type mismatch for result of {:?}",
28 let val = Immediate::ScalarPair(val.into(), Scalar::from_bool(overflowed).into());
29 self.write_immediate(val, dest)
32 /// Applies the binary operation `op` to the arguments and writes the result to the
34 pub fn binop_ignore_overflow(
37 left: &ImmTy<'tcx, M::PointerTag>,
38 right: &ImmTy<'tcx, M::PointerTag>,
39 dest: &PlaceTy<'tcx, M::PointerTag>,
40 ) -> InterpResult<'tcx> {
41 let (val, _overflowed, ty) = self.overflowing_binary_op(op, left, right)?;
42 assert_eq!(ty, dest.layout.ty, "type mismatch for result of {:?}", op);
43 self.write_scalar(val, dest)
47 impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
53 ) -> (Scalar<M::PointerTag>, bool, Ty<'tcx>) {
54 use rustc_middle::mir::BinOp::*;
56 let res = match bin_op {
63 _ => span_bug!(self.cur_span(), "Invalid operation on char: {:?}", bin_op),
65 (Scalar::from_bool(res), false, self.tcx.types.bool)
73 ) -> (Scalar<M::PointerTag>, bool, Ty<'tcx>) {
74 use rustc_middle::mir::BinOp::*;
76 let res = match bin_op {
86 _ => span_bug!(self.cur_span(), "Invalid operation on bool: {:?}", bin_op),
88 (Scalar::from_bool(res), false, self.tcx.types.bool)
91 fn binary_float_op<F: Float + Into<Scalar<M::PointerTag>>>(
97 ) -> (Scalar<M::PointerTag>, bool, Ty<'tcx>) {
98 use rustc_middle::mir::BinOp::*;
100 let (val, ty) = match bin_op {
101 Eq => (Scalar::from_bool(l == r), self.tcx.types.bool),
102 Ne => (Scalar::from_bool(l != r), self.tcx.types.bool),
103 Lt => (Scalar::from_bool(l < r), self.tcx.types.bool),
104 Le => (Scalar::from_bool(l <= r), self.tcx.types.bool),
105 Gt => (Scalar::from_bool(l > r), self.tcx.types.bool),
106 Ge => (Scalar::from_bool(l >= r), self.tcx.types.bool),
107 Add => ((l + r).value.into(), ty),
108 Sub => ((l - r).value.into(), ty),
109 Mul => ((l * r).value.into(), ty),
110 Div => ((l / r).value.into(), ty),
111 Rem => ((l % r).value.into(), ty),
112 _ => span_bug!(self.cur_span(), "invalid float op: `{:?}`", bin_op),
120 // passing in raw bits
122 left_layout: TyAndLayout<'tcx>,
124 right_layout: TyAndLayout<'tcx>,
125 ) -> InterpResult<'tcx, (Scalar<M::PointerTag>, bool, Ty<'tcx>)> {
126 use rustc_middle::mir::BinOp::*;
128 // Shift ops can have an RHS with a different numeric type.
129 if bin_op == Shl || bin_op == Shr {
130 let signed = left_layout.abi.is_signed();
131 let size = u128::from(left_layout.size.bits());
132 let overflow = r >= size;
133 // The shift offset is implicitly masked to the type size, to make sure this operation
134 // is always defined. This is the one MIR operator that does *not* directly map to a
135 // single LLVM operation. See
136 // <https://github.com/rust-lang/rust/blob/a3b9405ae7bb6ab4e8103b414e75c44598a10fd2/compiler/rustc_codegen_ssa/src/common.rs#L131-L158>
137 // for the corresponding truncation in our codegen backends.
139 let r = u32::try_from(r).unwrap(); // we masked so this will always fit
140 let result = if signed {
141 let l = self.sign_extend(l, left_layout) as i128;
142 let result = match bin_op {
143 Shl => l.checked_shl(r).unwrap(),
144 Shr => l.checked_shr(r).unwrap(),
145 _ => bug!("it has already been checked that this is a shift op"),
150 Shl => l.checked_shl(r).unwrap(),
151 Shr => l.checked_shr(r).unwrap(),
152 _ => bug!("it has already been checked that this is a shift op"),
155 let truncated = self.truncate(result, left_layout);
156 return Ok((Scalar::from_uint(truncated, left_layout.size), overflow, left_layout.ty));
159 // For the remaining ops, the types must be the same on both sides
160 if left_layout.ty != right_layout.ty {
163 "invalid asymmetric binary op {:?}: {:?} ({:?}), {:?} ({:?})",
172 let size = left_layout.size;
174 // Operations that need special treatment for signed integers
175 if left_layout.abi.is_signed() {
176 let op: Option<fn(&i128, &i128) -> bool> = match bin_op {
177 Lt => Some(i128::lt),
178 Le => Some(i128::le),
179 Gt => Some(i128::gt),
180 Ge => Some(i128::ge),
183 if let Some(op) = op {
184 let l = self.sign_extend(l, left_layout) as i128;
185 let r = self.sign_extend(r, right_layout) as i128;
186 return Ok((Scalar::from_bool(op(&l, &r)), false, self.tcx.types.bool));
188 let op: Option<fn(i128, i128) -> (i128, bool)> = match bin_op {
189 Div if r == 0 => throw_ub!(DivisionByZero),
190 Rem if r == 0 => throw_ub!(RemainderByZero),
191 Div => Some(i128::overflowing_div),
192 Rem => Some(i128::overflowing_rem),
193 Add => Some(i128::overflowing_add),
194 Sub => Some(i128::overflowing_sub),
195 Mul => Some(i128::overflowing_mul),
198 if let Some(op) = op {
199 let r = self.sign_extend(r, right_layout) as i128;
200 // We need a special check for overflowing remainder:
201 // "int_min % -1" overflows and returns 0, but after casting things to a larger int
202 // type it does *not* overflow nor give an unrepresentable result!
204 if r == -1 && l == (1 << (size.bits() - 1)) {
205 return Ok((Scalar::from_int(0, size), true, left_layout.ty));
208 let l = self.sign_extend(l, left_layout) as i128;
210 let (result, oflo) = op(l, r);
211 // This may be out-of-bounds for the result type, so we have to truncate ourselves.
212 // If that truncation loses any information, we have an overflow.
213 let result = result as u128;
214 let truncated = self.truncate(result, left_layout);
216 Scalar::from_uint(truncated, size),
217 oflo || self.sign_extend(truncated, left_layout) != result,
223 let (val, ty) = match bin_op {
224 Eq => (Scalar::from_bool(l == r), self.tcx.types.bool),
225 Ne => (Scalar::from_bool(l != r), self.tcx.types.bool),
227 Lt => (Scalar::from_bool(l < r), self.tcx.types.bool),
228 Le => (Scalar::from_bool(l <= r), self.tcx.types.bool),
229 Gt => (Scalar::from_bool(l > r), self.tcx.types.bool),
230 Ge => (Scalar::from_bool(l >= r), self.tcx.types.bool),
232 BitOr => (Scalar::from_uint(l | r, size), left_layout.ty),
233 BitAnd => (Scalar::from_uint(l & r, size), left_layout.ty),
234 BitXor => (Scalar::from_uint(l ^ r, size), left_layout.ty),
236 Add | Sub | Mul | Rem | Div => {
237 assert!(!left_layout.abi.is_signed());
238 let op: fn(u128, u128) -> (u128, bool) = match bin_op {
239 Add => u128::overflowing_add,
240 Sub => u128::overflowing_sub,
241 Mul => u128::overflowing_mul,
242 Div if r == 0 => throw_ub!(DivisionByZero),
243 Rem if r == 0 => throw_ub!(RemainderByZero),
244 Div => u128::overflowing_div,
245 Rem => u128::overflowing_rem,
248 let (result, oflo) = op(l, r);
249 // Truncate to target type.
250 // If that truncation loses any information, we have an overflow.
251 let truncated = self.truncate(result, left_layout);
253 Scalar::from_uint(truncated, size),
254 oflo || truncated != result,
261 "invalid binary op {:?}: {:?}, {:?} (both {:?})",
272 /// Returns the result of the specified operation, whether it overflowed, and
274 pub fn overflowing_binary_op(
277 left: &ImmTy<'tcx, M::PointerTag>,
278 right: &ImmTy<'tcx, M::PointerTag>,
279 ) -> InterpResult<'tcx, (Scalar<M::PointerTag>, bool, Ty<'tcx>)> {
281 "Running binary op {:?}: {:?} ({:?}), {:?} ({:?})",
289 match left.layout.ty.kind() {
291 assert_eq!(left.layout.ty, right.layout.ty);
292 let left = left.to_scalar()?;
293 let right = right.to_scalar()?;
294 Ok(self.binary_char_op(bin_op, left.to_char()?, right.to_char()?))
297 assert_eq!(left.layout.ty, right.layout.ty);
298 let left = left.to_scalar()?;
299 let right = right.to_scalar()?;
300 Ok(self.binary_bool_op(bin_op, left.to_bool()?, right.to_bool()?))
303 assert_eq!(left.layout.ty, right.layout.ty);
304 let ty = left.layout.ty;
305 let left = left.to_scalar()?;
306 let right = right.to_scalar()?;
309 self.binary_float_op(bin_op, ty, left.to_f32()?, right.to_f32()?)
312 self.binary_float_op(bin_op, ty, left.to_f64()?, right.to_f64()?)
316 _ if left.layout.ty.is_integral() => {
317 // the RHS type can be different, e.g. for shifts -- but it has to be integral, too
319 right.layout.ty.is_integral(),
320 "Unexpected types for BinOp: {:?} {:?} {:?}",
326 let l = left.to_scalar()?.to_bits(left.layout.size)?;
327 let r = right.to_scalar()?.to_bits(right.layout.size)?;
328 self.binary_int_op(bin_op, l, left.layout, r, right.layout)
330 _ if left.layout.ty.is_any_ptr() => {
331 // The RHS type must be a `pointer` *or an integer type* (for `Offset`).
332 // (Even when both sides are pointers, their type might differ, see issue #91636)
334 right.layout.ty.is_any_ptr() || right.layout.ty.is_integral(),
335 "Unexpected types for BinOp: {:?} {:?} {:?}",
341 M::binary_ptr_op(self, bin_op, left, right)
345 "Invalid MIR: bad LHS type for binop: {:?}",
351 /// Typed version of `overflowing_binary_op`, returning an `ImmTy`. Also ignores overflows.
356 left: &ImmTy<'tcx, M::PointerTag>,
357 right: &ImmTy<'tcx, M::PointerTag>,
358 ) -> InterpResult<'tcx, ImmTy<'tcx, M::PointerTag>> {
359 let (val, _overflow, ty) = self.overflowing_binary_op(bin_op, left, right)?;
360 Ok(ImmTy::from_scalar(val, self.layout_of(ty)?))
363 /// Returns the result of the specified operation, whether it overflowed, and
365 pub fn overflowing_unary_op(
368 val: &ImmTy<'tcx, M::PointerTag>,
369 ) -> InterpResult<'tcx, (Scalar<M::PointerTag>, bool, Ty<'tcx>)> {
370 use rustc_middle::mir::UnOp::*;
372 let layout = val.layout;
373 let val = val.to_scalar()?;
374 trace!("Running unary op {:?}: {:?} ({:?})", un_op, val, layout.ty);
376 match layout.ty.kind() {
378 let val = val.to_bool()?;
379 let res = match un_op {
381 _ => span_bug!(self.cur_span(), "Invalid bool op {:?}", un_op),
383 Ok((Scalar::from_bool(res), false, self.tcx.types.bool))
386 let res = match (un_op, fty) {
387 (Neg, FloatTy::F32) => Scalar::from_f32(-val.to_f32()?),
388 (Neg, FloatTy::F64) => Scalar::from_f64(-val.to_f64()?),
389 _ => span_bug!(self.cur_span(), "Invalid float op {:?}", un_op),
391 Ok((res, false, layout.ty))
394 assert!(layout.ty.is_integral());
395 let val = val.to_bits(layout.size)?;
396 let (res, overflow) = match un_op {
397 Not => (self.truncate(!val, layout), false), // bitwise negation, then truncate
399 // arithmetic negation
400 assert!(layout.abi.is_signed());
401 let val = self.sign_extend(val, layout) as i128;
402 let (res, overflow) = val.overflowing_neg();
403 let res = res as u128;
404 // Truncate to target type.
405 // If that truncation loses any information, we have an overflow.
406 let truncated = self.truncate(res, layout);
407 (truncated, overflow || self.sign_extend(truncated, layout) != res)
410 Ok((Scalar::from_uint(res, layout.size), overflow, layout.ty))
418 val: &ImmTy<'tcx, M::PointerTag>,
419 ) -> InterpResult<'tcx, ImmTy<'tcx, M::PointerTag>> {
420 let (val, _overflow, ty) = self.overflowing_unary_op(un_op, val)?;
421 Ok(ImmTy::from_scalar(val, self.layout_of(ty)?))