e6376631cc
detects redundant imports that can be eliminated. for #117772 : In order to facilitate review and modification, split the checking code and removing redundant imports code into two PR.
40 lines
1.1 KiB
Rust
40 lines
1.1 KiB
Rust
//! SSA analysis
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use rustc_index::IndexVec;
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use rustc_middle::mir::StatementKind::*;
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use crate::prelude::*;
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#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
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pub(crate) enum SsaKind {
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NotSsa,
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MaybeSsa,
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}
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impl SsaKind {
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pub(crate) fn is_ssa<'tcx>(self, fx: &FunctionCx<'_, '_, 'tcx>, ty: Ty<'tcx>) -> bool {
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self == SsaKind::MaybeSsa && (fx.clif_type(ty).is_some() || fx.clif_pair_type(ty).is_some())
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}
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}
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pub(crate) fn analyze(fx: &FunctionCx<'_, '_, '_>) -> IndexVec<Local, SsaKind> {
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let mut flag_map =
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fx.mir.local_decls.iter().map(|_| SsaKind::MaybeSsa).collect::<IndexVec<Local, SsaKind>>();
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for bb in fx.mir.basic_blocks.iter() {
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for stmt in bb.statements.iter() {
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match &stmt.kind {
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Assign(place_and_rval) => match &place_and_rval.1 {
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Rvalue::Ref(_, _, place) | Rvalue::AddressOf(_, place) => {
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flag_map[place.local] = SsaKind::NotSsa;
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}
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_ => {}
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},
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_ => {}
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}
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}
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}
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flag_map
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}
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