diff options
| -rw-r--r-- | compiler/rustc_data_structures/src/graph/dominators/mod.rs | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/compiler/rustc_data_structures/src/graph/dominators/mod.rs b/compiler/rustc_data_structures/src/graph/dominators/mod.rs index 0d2ae115cb0..00913a483db 100644 --- a/compiler/rustc_data_structures/src/graph/dominators/mod.rs +++ b/compiler/rustc_data_structures/src/graph/dominators/mod.rs @@ -241,9 +241,19 @@ fn compress( v: PreorderIndex, ) { assert!(is_processed(v, lastlinked)); - let u = ancestor[v]; - if is_processed(u, lastlinked) { - compress(ancestor, lastlinked, semi, label, u); + // Compute the processed list of ancestors + // + // We use a heap stack here to avoid recursing too deeply, exhausting the + // stack space. + let mut stack: smallvec::SmallVec<[_; 8]> = smallvec::smallvec![v]; + let mut u = ancestor[v]; + while is_processed(u, lastlinked) { + stack.push(u); + u = ancestor[u]; + } + + // Then in reverse order, popping the stack + for &[v, u] in stack.array_windows().rev() { if semi[label[u]] < semi[label[v]] { label[v] = label[u]; } |