diff options
Diffstat (limited to 'compiler/rustc_mir_dataflow/src/storage.rs')
-rw-r--r-- | compiler/rustc_mir_dataflow/src/storage.rs | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/compiler/rustc_mir_dataflow/src/storage.rs b/compiler/rustc_mir_dataflow/src/storage.rs new file mode 100644 index 000000000..c909648ea --- /dev/null +++ b/compiler/rustc_mir_dataflow/src/storage.rs @@ -0,0 +1,20 @@ +use rustc_index::bit_set::BitSet; +use rustc_middle::mir::{self, Local}; + +/// The set of locals in a MIR body that do not have `StorageLive`/`StorageDead` annotations. +/// +/// These locals have fixed storage for the duration of the body. +pub fn always_storage_live_locals(body: &mir::Body<'_>) -> BitSet<Local> { + let mut always_live_locals = BitSet::new_filled(body.local_decls.len()); + + for block in body.basic_blocks() { + for statement in &block.statements { + use mir::StatementKind::{StorageDead, StorageLive}; + if let StorageLive(l) | StorageDead(l) = statement.kind { + always_live_locals.remove(l); + } + } + } + + always_live_locals +} |