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use crate::mir::graph_cyclic_cache::GraphIsCyclicCache;
use crate::mir::predecessors::{PredecessorCache, Predecessors};
use crate::mir::switch_sources::{SwitchSourceCache, SwitchSources};
use crate::mir::traversal::PostorderCache;
use crate::mir::{BasicBlock, BasicBlockData, Successors, START_BLOCK};
use rustc_data_structures::graph;
use rustc_data_structures::graph::dominators::{dominators, Dominators};
use rustc_index::vec::IndexVec;
#[derive(Clone, TyEncodable, TyDecodable, Debug, HashStable, TypeFoldable, TypeVisitable)]
pub struct BasicBlocks<'tcx> {
basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
predecessor_cache: PredecessorCache,
switch_source_cache: SwitchSourceCache,
is_cyclic: GraphIsCyclicCache,
postorder_cache: PostorderCache,
}
impl<'tcx> BasicBlocks<'tcx> {
#[inline]
pub fn new(basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>) -> Self {
BasicBlocks {
basic_blocks,
predecessor_cache: PredecessorCache::new(),
switch_source_cache: SwitchSourceCache::new(),
is_cyclic: GraphIsCyclicCache::new(),
postorder_cache: PostorderCache::new(),
}
}
/// Returns true if control-flow graph contains a cycle reachable from the `START_BLOCK`.
#[inline]
pub fn is_cfg_cyclic(&self) -> bool {
self.is_cyclic.is_cyclic(self)
}
#[inline]
pub fn dominators(&self) -> Dominators<BasicBlock> {
dominators(&self)
}
/// Returns predecessors for each basic block.
#[inline]
pub fn predecessors(&self) -> &Predecessors {
self.predecessor_cache.compute(&self.basic_blocks)
}
/// Returns basic blocks in a postorder.
#[inline]
pub fn postorder(&self) -> &[BasicBlock] {
self.postorder_cache.compute(&self.basic_blocks)
}
/// `switch_sources()[&(target, switch)]` returns a list of switch
/// values that lead to a `target` block from a `switch` block.
#[inline]
pub fn switch_sources(&self) -> &SwitchSources {
self.switch_source_cache.compute(&self.basic_blocks)
}
/// Returns mutable reference to basic blocks. Invalidates CFG cache.
#[inline]
pub fn as_mut(&mut self) -> &mut IndexVec<BasicBlock, BasicBlockData<'tcx>> {
self.invalidate_cfg_cache();
&mut self.basic_blocks
}
/// Get mutable access to basic blocks without invalidating the CFG cache.
///
/// By calling this method instead of e.g. [`BasicBlocks::as_mut`] you promise not to change
/// the CFG. This means that
///
/// 1) The number of basic blocks remains unchanged
/// 2) The set of successors of each terminator remains unchanged.
/// 3) For each `TerminatorKind::SwitchInt`, the `targets` remains the same and the terminator
/// kind is not changed.
///
/// If any of these conditions cannot be upheld, you should call [`BasicBlocks::invalidate_cfg_cache`].
#[inline]
pub fn as_mut_preserves_cfg(&mut self) -> &mut IndexVec<BasicBlock, BasicBlockData<'tcx>> {
&mut self.basic_blocks
}
/// Invalidates cached information about the CFG.
///
/// You will only ever need this if you have also called [`BasicBlocks::as_mut_preserves_cfg`].
/// All other methods that allow you to mutate the basic blocks also call this method
/// themselves, thereby avoiding any risk of accidentally cache invalidation.
pub fn invalidate_cfg_cache(&mut self) {
self.predecessor_cache.invalidate();
self.switch_source_cache.invalidate();
self.is_cyclic.invalidate();
self.postorder_cache.invalidate();
}
}
impl<'tcx> std::ops::Deref for BasicBlocks<'tcx> {
type Target = IndexVec<BasicBlock, BasicBlockData<'tcx>>;
#[inline]
fn deref(&self) -> &IndexVec<BasicBlock, BasicBlockData<'tcx>> {
&self.basic_blocks
}
}
impl<'tcx> graph::DirectedGraph for BasicBlocks<'tcx> {
type Node = BasicBlock;
}
impl<'tcx> graph::WithNumNodes for BasicBlocks<'tcx> {
#[inline]
fn num_nodes(&self) -> usize {
self.basic_blocks.len()
}
}
impl<'tcx> graph::WithStartNode for BasicBlocks<'tcx> {
#[inline]
fn start_node(&self) -> Self::Node {
START_BLOCK
}
}
impl<'tcx> graph::WithSuccessors for BasicBlocks<'tcx> {
#[inline]
fn successors(&self, node: Self::Node) -> <Self as graph::GraphSuccessors<'_>>::Iter {
self.basic_blocks[node].terminator().successors()
}
}
impl<'a, 'b> graph::GraphSuccessors<'b> for BasicBlocks<'a> {
type Item = BasicBlock;
type Iter = Successors<'b>;
}
impl<'tcx, 'graph> graph::GraphPredecessors<'graph> for BasicBlocks<'tcx> {
type Item = BasicBlock;
type Iter = std::iter::Copied<std::slice::Iter<'graph, BasicBlock>>;
}
impl<'tcx> graph::WithPredecessors for BasicBlocks<'tcx> {
#[inline]
fn predecessors(&self, node: Self::Node) -> <Self as graph::GraphPredecessors<'_>>::Iter {
self.predecessors()[node].iter().copied()
}
}
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