pub use super::query::*;
+#[derive(Debug, Clone, TyEncodable, TyDecodable, HashStable, PartialEq)]
+pub struct SwitchTargets<'tcx> {
+ /// Possible values. The locations to branch to in each case
+ /// are found in the corresponding indices from the `targets` vector.
+ values: Cow<'tcx, [u128]>,
+
+ /// Possible branch sites. The last element of this vector is used
+ /// for the otherwise branch, so targets.len() == values.len() + 1
+ /// should hold.
+ //
+ // This invariant is quite non-obvious and also could be improved.
+ // One way to make this invariant is to have something like this instead:
+ //
+ // branches: Vec<(ConstInt, BasicBlock)>,
+ // otherwise: Option<BasicBlock> // exhaustive if None
+ //
+ // However we’ve decided to keep this as-is until we figure a case
+ // where some other approach seems to be strictly better than other.
+ targets: Vec<BasicBlock>,
+}
+
+impl<'tcx> SwitchTargets<'tcx> {
+ /// Creates switch targets from an iterator of values and target blocks.
+ ///
+ /// The iterator may be empty, in which case the `SwitchInt` instruction is equivalent to
+ /// `goto otherwise;`.
+ pub fn new(targets: impl Iterator<Item = (u128, BasicBlock)>, otherwise: BasicBlock) -> Self {
+ let (values, mut targets): (Vec<_>, Vec<_>) = targets.unzip();
+ targets.push(otherwise);
+ Self { values: values.into(), targets }
+ }
+
+ /// Builds a switch targets definition that jumps to `then` if the tested value equals `value`,
+ /// and to `else_` if not.
+ pub fn static_if(value: &'static [u128; 1], then: BasicBlock, else_: BasicBlock) -> Self {
+ Self { values: Cow::Borrowed(value), targets: vec![then, else_] }
+ }
+
+ /// Returns the fallback target that is jumped to when none of the values match the operand.
+ pub fn otherwise(&self) -> BasicBlock {
+ *self.targets.last().unwrap()
+ }
+
+ /// Returns an iterator over the switch targets.
+ ///
+ /// The iterator will yield tuples containing the value and corresponding target to jump to, not
+ /// including the `otherwise` fallback target.
+ ///
+ /// Note that this may yield 0 elements. Only the `otherwise` branch is mandatory.
+ pub fn iter(&self) -> SwitchTargetsIter<'_> {
+ SwitchTargetsIter { inner: self.values.iter().zip(self.targets.iter()) }
+ }
+
+ /// Returns a slice with all possible jump targets (including the fallback target).
+ pub fn all_targets(&self) -> &[BasicBlock] {
+ &self.targets
+ }
+
+ pub fn all_targets_mut(&mut self) -> &mut [BasicBlock] {
+ &mut self.targets
+ }
+}
+
+pub struct SwitchTargetsIter<'a> {
+ inner: iter::Zip<slice::Iter<'a, u128>, slice::Iter<'a, BasicBlock>>,
+}
+
+impl<'a> Iterator for SwitchTargetsIter<'a> {
+ type Item = (u128, BasicBlock);
+
+ fn next(&mut self) -> Option<Self::Item> {
+ self.inner.next().map(|(val, bb)| (*val, *bb))
+ }
+
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ self.inner.size_hint()
+ }
+}
+
+impl<'a> ExactSizeIterator for SwitchTargetsIter<'a> {}
+
#[derive(Clone, TyEncodable, TyDecodable, HashStable, PartialEq)]
pub enum TerminatorKind<'tcx> {
/// Block should have one successor in the graph; we jump there.
/// FIXME: remove this redundant information. Currently, it is relied on by pretty-printing.
switch_ty: Ty<'tcx>,
- /// Possible values. The locations to branch to in each case
- /// are found in the corresponding indices from the `targets` vector.
- values: Cow<'tcx, [u128]>,
-
- /// Possible branch sites. The last element of this vector is used
- /// for the otherwise branch, so targets.len() == values.len() + 1
- /// should hold.
- //
- // This invariant is quite non-obvious and also could be improved.
- // One way to make this invariant is to have something like this instead:
- //
- // branches: Vec<(ConstInt, BasicBlock)>,
- // otherwise: Option<BasicBlock> // exhaustive if None
- //
- // However we’ve decided to keep this as-is until we figure a case
- // where some other approach seems to be strictly better than other.
- targets: Vec<BasicBlock>,
+ targets: SwitchTargets<'tcx>,
},
/// Indicates that the landing pad is finished and unwinding should
t: BasicBlock,
f: BasicBlock,
) -> TerminatorKind<'tcx> {
- static BOOL_SWITCH_FALSE: &[u128] = &[0];
TerminatorKind::SwitchInt {
discr: cond,
switch_ty: tcx.types.bool,
- values: From::from(BOOL_SWITCH_FALSE),
- targets: vec![f, t],
+ targets: SwitchTargets::static_if(&[0], f, t),
}
}
| FalseUnwind { real_target: ref t, unwind: Some(ref u) } => {
Some(t).into_iter().chain(slice::from_ref(u))
}
- SwitchInt { ref targets, .. } => None.into_iter().chain(&targets[..]),
+ SwitchInt { ref targets, .. } => None.into_iter().chain(&targets.targets[..]),
FalseEdge { ref real_target, ref imaginary_target } => {
Some(real_target).into_iter().chain(slice::from_ref(imaginary_target))
}
| FalseUnwind { real_target: ref mut t, unwind: Some(ref mut u) } => {
Some(t).into_iter().chain(slice::from_mut(u))
}
- SwitchInt { ref mut targets, .. } => None.into_iter().chain(&mut targets[..]),
+ SwitchInt { ref mut targets, .. } => None.into_iter().chain(&mut targets.targets[..]),
FalseEdge { ref mut real_target, ref mut imaginary_target } => {
Some(real_target).into_iter().chain(slice::from_mut(imaginary_target))
}
match *self {
Return | Resume | Abort | Unreachable | GeneratorDrop => vec![],
Goto { .. } => vec!["".into()],
- SwitchInt { ref values, switch_ty, .. } => ty::tls::with(|tcx| {
+ SwitchInt { ref targets, switch_ty, .. } => ty::tls::with(|tcx| {
let param_env = ty::ParamEnv::empty();
let switch_ty = tcx.lift(&switch_ty).unwrap();
let size = tcx.layout_of(param_env.and(switch_ty)).unwrap().size;
- values
+ targets
+ .values
.iter()
.map(|&u| {
ty::Const::from_scalar(tcx, Scalar::from_uint(u, size), switch_ty)
projects / rust.git / blobdiff