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.

Sign up for GitHub

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

Note that BasicBlock is just an index #78035

Merged
merged 1 commit into from
Oct 18, 2020
Merged

Note that BasicBlock is just an index #78035

Changes from all commits
Commits
Show all changes
1 commit
Select commit
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
5 changes: 4 additions & 1 deletion compiler/rustc_middle/src/mir/mod.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -146,7 +146,7 @@ impl<'tcx> MirSource<'tcx> {
/// The lowered representation of a single function.
#[derive(Clone, TyEncodable, TyDecodable, Debug, HashStable, TypeFoldable)]
pub struct Body<'tcx> {
/// A list of basic blocks. References to basic block use a newtyped index type `BasicBlock`
/// A list of basic blocks. References to basic block use a newtyped index type [`BasicBlock`]
/// that indexes into this vector.
basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,

Expand Down Expand Up @@ -1106,6 +1106,9 @@ rustc_index::newtype_index! {
/// are edges that go from a multi-successor node to a multi-predecessor node. This pass is
/// needed because some analyses require that there are no critical edges in the CFG.
///
/// Note that this type is just an index into [`Body.basic_blocks`](Body::basic_blocks);
Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Are there other places where BasicBlock is an index?

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I don't really understand the question?

Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I wasn’t sure if there are other places where it is an index into a vector of blocks and I want to make sure I don’t mislead people by saying that it’s an index into specifically Body when in fact there are other places that hold a vector of blocks that are indexed by BasicBlock. Hope that was clearer!

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Ah I see, thanks for clarifying.

I don't think there are other lists this is an index into, but you can audit all IndexVec<BasicBlock, _> if you want to be sure.

/// the actual data that a basic block holds is in [`BasicBlockData`].
///
/// Read more about basic blocks in the [rustc-dev-guide][guide-mir].
///
/// [CFG]: https://rustc-dev-guide.rust-lang.org/appendix/background.html#cfg
Expand Down