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| 1 | +use crate::mir::graph_cyclic_cache::GraphIsCyclicCache; |
| 2 | +use crate::mir::predecessors::{PredecessorCache, Predecessors}; |
| 3 | +use crate::mir::switch_sources::{SwitchSourceCache, SwitchSources}; |
| 4 | +use crate::mir::traversal::PostorderCache; |
| 5 | +use crate::mir::{BasicBlock, BasicBlockData, Successors, START_BLOCK}; |
| 6 | + |
| 7 | +use rustc_data_structures::graph; |
| 8 | +use rustc_data_structures::graph::dominators::{dominators, Dominators}; |
| 9 | +use rustc_index::vec::IndexVec; |
| 10 | + |
| 11 | +#[derive(Clone, TyEncodable, TyDecodable, Debug, HashStable, TypeFoldable, TypeVisitable)] |
| 12 | +pub struct BasicBlocks<'tcx> { |
| 13 | + basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>, |
| 14 | + predecessor_cache: PredecessorCache, |
| 15 | + switch_source_cache: SwitchSourceCache, |
| 16 | + is_cyclic: GraphIsCyclicCache, |
| 17 | + postorder_cache: PostorderCache, |
| 18 | +} |
| 19 | + |
| 20 | +impl<'tcx> BasicBlocks<'tcx> { |
| 21 | + #[inline] |
| 22 | + pub fn new(basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>) -> Self { |
| 23 | + BasicBlocks { |
| 24 | + basic_blocks, |
| 25 | + predecessor_cache: PredecessorCache::new(), |
| 26 | + switch_source_cache: SwitchSourceCache::new(), |
| 27 | + is_cyclic: GraphIsCyclicCache::new(), |
| 28 | + postorder_cache: PostorderCache::new(), |
| 29 | + } |
| 30 | + } |
| 31 | + |
| 32 | + /// Returns true if control-flow graph contains a cycle reachable from the `START_BLOCK`. |
| 33 | + #[inline] |
| 34 | + pub fn is_cfg_cyclic(&self) -> bool { |
| 35 | + self.is_cyclic.is_cyclic(self) |
| 36 | + } |
| 37 | + |
| 38 | + #[inline] |
| 39 | + pub fn dominators(&self) -> Dominators<BasicBlock> { |
| 40 | + dominators(&self) |
| 41 | + } |
| 42 | + |
| 43 | + /// Returns predecessors for each basic block. |
| 44 | + #[inline] |
| 45 | + pub fn predecessors(&self) -> &Predecessors { |
| 46 | + self.predecessor_cache.compute(&self.basic_blocks) |
| 47 | + } |
| 48 | + |
| 49 | + /// Returns basic blocks in a postorder. |
| 50 | + #[inline] |
| 51 | + pub fn postorder(&self) -> &[BasicBlock] { |
| 52 | + self.postorder_cache.compute(&self.basic_blocks) |
| 53 | + } |
| 54 | + |
| 55 | + /// `switch_sources()[&(target, switch)]` returns a list of switch |
| 56 | + /// values that lead to a `target` block from a `switch` block. |
| 57 | + #[inline] |
| 58 | + pub fn switch_sources(&self) -> &SwitchSources { |
| 59 | + self.switch_source_cache.compute(&self.basic_blocks) |
| 60 | + } |
| 61 | + |
| 62 | + /// Returns mutable reference to basic blocks. Invalidates CFG cache. |
| 63 | + #[inline] |
| 64 | + pub fn as_mut(&mut self) -> &mut IndexVec<BasicBlock, BasicBlockData<'tcx>> { |
| 65 | + self.invalidate_cfg_cache(); |
| 66 | + &mut self.basic_blocks |
| 67 | + } |
| 68 | + |
| 69 | + /// Get mutable access to basic blocks without invalidating the CFG cache. |
| 70 | + /// |
| 71 | + /// By calling this method instead of e.g. [`BasicBlocks::as_mut`] you promise not to change |
| 72 | + /// the CFG. This means that |
| 73 | + /// |
| 74 | + /// 1) The number of basic blocks remains unchanged |
| 75 | + /// 2) The set of successors of each terminator remains unchanged. |
| 76 | + /// 3) For each `TerminatorKind::SwitchInt`, the `targets` remains the same and the terminator |
| 77 | + /// kind is not changed. |
| 78 | + /// |
| 79 | + /// If any of these conditions cannot be upheld, you should call [`BasicBlocks::invalidate_cfg_cache`]. |
| 80 | + #[inline] |
| 81 | + pub fn as_mut_preserves_cfg(&mut self) -> &mut IndexVec<BasicBlock, BasicBlockData<'tcx>> { |
| 82 | + &mut self.basic_blocks |
| 83 | + } |
| 84 | + |
| 85 | + /// Invalidates cached information about the CFG. |
| 86 | + /// |
| 87 | + /// You will only ever need this if you have also called [`BasicBlocks::as_mut_preserves_cfg`]. |
| 88 | + /// All other methods that allow you to mutate the basic blocks also call this method |
| 89 | + /// themselves, thereby avoiding any risk of accidentaly cache invalidation. |
| 90 | + pub fn invalidate_cfg_cache(&mut self) { |
| 91 | + self.predecessor_cache.invalidate(); |
| 92 | + self.switch_source_cache.invalidate(); |
| 93 | + self.is_cyclic.invalidate(); |
| 94 | + self.postorder_cache.invalidate(); |
| 95 | + } |
| 96 | +} |
| 97 | + |
| 98 | +impl<'tcx> std::ops::Deref for BasicBlocks<'tcx> { |
| 99 | + type Target = IndexVec<BasicBlock, BasicBlockData<'tcx>>; |
| 100 | + |
| 101 | + #[inline] |
| 102 | + fn deref(&self) -> &IndexVec<BasicBlock, BasicBlockData<'tcx>> { |
| 103 | + &self.basic_blocks |
| 104 | + } |
| 105 | +} |
| 106 | + |
| 107 | +impl<'tcx> graph::DirectedGraph for BasicBlocks<'tcx> { |
| 108 | + type Node = BasicBlock; |
| 109 | +} |
| 110 | + |
| 111 | +impl<'tcx> graph::WithNumNodes for BasicBlocks<'tcx> { |
| 112 | + #[inline] |
| 113 | + fn num_nodes(&self) -> usize { |
| 114 | + self.basic_blocks.len() |
| 115 | + } |
| 116 | +} |
| 117 | + |
| 118 | +impl<'tcx> graph::WithStartNode for BasicBlocks<'tcx> { |
| 119 | + #[inline] |
| 120 | + fn start_node(&self) -> Self::Node { |
| 121 | + START_BLOCK |
| 122 | + } |
| 123 | +} |
| 124 | + |
| 125 | +impl<'tcx> graph::WithSuccessors for BasicBlocks<'tcx> { |
| 126 | + #[inline] |
| 127 | + fn successors(&self, node: Self::Node) -> <Self as graph::GraphSuccessors<'_>>::Iter { |
| 128 | + self.basic_blocks[node].terminator().successors() |
| 129 | + } |
| 130 | +} |
| 131 | + |
| 132 | +impl<'a, 'b> graph::GraphSuccessors<'b> for BasicBlocks<'a> { |
| 133 | + type Item = BasicBlock; |
| 134 | + type Iter = Successors<'b>; |
| 135 | +} |
| 136 | + |
| 137 | +impl<'tcx, 'graph> graph::GraphPredecessors<'graph> for BasicBlocks<'tcx> { |
| 138 | + type Item = BasicBlock; |
| 139 | + type Iter = std::iter::Copied<std::slice::Iter<'graph, BasicBlock>>; |
| 140 | +} |
| 141 | + |
| 142 | +impl<'tcx> graph::WithPredecessors for BasicBlocks<'tcx> { |
| 143 | + #[inline] |
| 144 | + fn predecessors(&self, node: Self::Node) -> <Self as graph::GraphPredecessors<'_>>::Iter { |
| 145 | + self.predecessors()[node].iter().copied() |
| 146 | + } |
| 147 | +} |
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