Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Unimplement ExactSizeIterator for MIR traversing iterators #55271

Merged
merged 1 commit into from
Oct 26, 2018
Merged
Changes from all commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
36 changes: 24 additions & 12 deletions src/librustc/mir/traversal.rs
Original file line number Diff line number Diff line change
Expand Up @@ -34,6 +34,7 @@ pub struct Preorder<'a, 'tcx: 'a> {
mir: &'a Mir<'tcx>,
visited: BitSet<BasicBlock>,
worklist: Vec<BasicBlock>,
root_is_start_block: bool,
}

impl<'a, 'tcx> Preorder<'a, 'tcx> {
Expand All @@ -44,6 +45,7 @@ impl<'a, 'tcx> Preorder<'a, 'tcx> {
mir,
visited: BitSet::new_empty(mir.basic_blocks().len()),
worklist,
root_is_start_block: root == START_BLOCK,
}
}
}
Expand Down Expand Up @@ -75,15 +77,19 @@ impl<'a, 'tcx> Iterator for Preorder<'a, 'tcx> {

fn size_hint(&self) -> (usize, Option<usize>) {
// All the blocks, minus the number of blocks we've visited.
let remaining = self.mir.basic_blocks().len() - self.visited.count();
let upper = self.mir.basic_blocks().len() - self.visited.count();

// We will visit all remaining blocks exactly once.
(remaining, Some(remaining))
let lower = if self.root_is_start_block {
// We will visit all remaining blocks exactly once.
upper
} else {
self.worklist.len()
};

(lower, Some(upper))
}
}

impl<'a, 'tcx> ExactSizeIterator for Preorder<'a, 'tcx> {}

/// Postorder traversal of a graph.
///
/// Postorder traversal is when each node is visited after all of it's
Expand All @@ -105,15 +111,17 @@ impl<'a, 'tcx> ExactSizeIterator for Preorder<'a, 'tcx> {}
pub struct Postorder<'a, 'tcx: 'a> {
mir: &'a Mir<'tcx>,
visited: BitSet<BasicBlock>,
visit_stack: Vec<(BasicBlock, Successors<'a>)>
visit_stack: Vec<(BasicBlock, Successors<'a>)>,
root_is_start_block: bool,
}

impl<'a, 'tcx> Postorder<'a, 'tcx> {
pub fn new(mir: &'a Mir<'tcx>, root: BasicBlock) -> Postorder<'a, 'tcx> {
let mut po = Postorder {
mir,
visited: BitSet::new_empty(mir.basic_blocks().len()),
visit_stack: Vec::new()
visit_stack: Vec::new(),
root_is_start_block: root == START_BLOCK,
};


Expand Down Expand Up @@ -214,15 +222,19 @@ impl<'a, 'tcx> Iterator for Postorder<'a, 'tcx> {

fn size_hint(&self) -> (usize, Option<usize>) {
// All the blocks, minus the number of blocks we've visited.
let remaining = self.mir.basic_blocks().len() - self.visited.count();
let upper = self.mir.basic_blocks().len() - self.visited.count();

// We will visit all remaining blocks exactly once.
(remaining, Some(remaining))
let lower = if self.root_is_start_block {
// We will visit all remaining blocks exactly once.
upper
} else {
self.visit_stack.len()
};

(lower, Some(upper))
}
}

impl<'a, 'tcx> ExactSizeIterator for Postorder<'a, 'tcx> {}

/// Reverse postorder traversal of a graph
///
/// Reverse postorder is the reverse order of a postorder traversal.
Expand Down