Auto merge of #123272 - saethlin:reachable-mono-cleanup, r= · rust-lang/rust@93c3b66 (original) (raw)
`@@ -30,7 +30,6 @@ pub use rustc_ast::Mutability;
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`use rustc_data_structures::fx::FxHashMap;
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`use rustc_data_structures::fx::FxHashSet;
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`use rustc_data_structures::graph::dominators::Dominators;
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``
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use rustc_data_structures::stack::ensure_sufficient_stack;
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`use rustc_index::bit_set::BitSet;
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`use rustc_index::{Idx, IndexSlice, IndexVec};
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`use rustc_serialize::{Decodable, Encodable};
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`@@ -687,57 +686,6 @@ impl<'tcx> Body<'tcx> {
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`self.injection_phase.is_some()
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`}
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``
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/// Finds which basic blocks are actually reachable for a specific
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/// monomorphization of this body.
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///
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/// This is allowed to have false positives; just because this says a block
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/// is reachable doesn't mean that's necessarily true. It's thus always
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/// legal for this to return a filled set.
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///
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/// Regardless, the [BitSet::domain_size] of the returned set will always
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/// exactly match the number of blocks in the body so that contains
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/// checks can be done without worrying about panicking.
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///
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/// This is mostly useful because it lets us skip lowering the false side
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/// of if <T as Trait>::CONST, as well as intrinsics::debug_assertions.
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pub fn reachable_blocks_in_mono(
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&self,
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tcx: TyCtxt<'tcx>,
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instance: Instance<'tcx>,
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) -> BitSet {
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let mut set = BitSet::new_empty(self.basic_blocks.len());
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self.reachable_blocks_in_mono_from(tcx, instance, &mut set, START_BLOCK);
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set
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}
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fn reachable_blocks_in_mono_from(
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&self,
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tcx: TyCtxt<'tcx>,
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instance: Instance<'tcx>,
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set: &mut BitSet,
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bb: BasicBlock,
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) {
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if !set.insert(bb) {
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return;
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}
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let data = &self.basic_blocks[bb];
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if let Some((bits, targets)) = Self::try_const_mono_switchint(tcx, instance, data) {
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let target = targets.target_for_value(bits);
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ensure_sufficient_stack(|| {
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self.reachable_blocks_in_mono_from(tcx, instance, set, target)
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});
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return;
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}
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for target in data.terminator().successors() {
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ensure_sufficient_stack(|| {
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self.reachable_blocks_in_mono_from(tcx, instance, set, target)
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});
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}
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}
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`` /// If this basic block ends with a [TerminatorKind::SwitchInt] for which we can evaluate the
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`/// dimscriminant in monomorphization, we return the discriminant bits and the
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`` /// [SwitchTargets], just so the caller doesn't also have to match on the terminator.
``