compiler/rustc_codegen_cranelift/src/analyze.rs

   1 //! SSA analysis
   2
   3 use crate::prelude::*;
   4
   5 use rustc_index::vec::IndexVec;
   6 use rustc_middle::mir::StatementKind::*;
   7
   8 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
   9 pub(crate) enum SsaKind {
  10     NotSsa,
  11     Ssa,
  12 }
  13
  14 pub(crate) fn analyze(fx: &FunctionCx<'_, '_, '_>) -> IndexVec<Local, SsaKind> {
  15     let mut flag_map = fx
  16         .mir
  17         .local_decls
  18         .iter()
  19         .map(|local_decl| {
  20             let ty = fx.monomorphize(local_decl.ty);
  21             if fx.clif_type(ty).is_some() || fx.clif_pair_type(ty).is_some() {
  22                 SsaKind::Ssa
  23             } else {
  24                 SsaKind::NotSsa
  25             }
  26         })
  27         .collect::<IndexVec<Local, SsaKind>>();
  28
  29     for bb in fx.mir.basic_blocks().iter() {
  30         for stmt in bb.statements.iter() {
  31             match &stmt.kind {
  32                 Assign(place_and_rval) => match &place_and_rval.1 {
  33                     Rvalue::Ref(_, _, place) | Rvalue::AddressOf(_, place) => {
  34                         not_ssa(&mut flag_map, place.local)
  35                     }
  36                     _ => {}
  37                 },
  38                 _ => {}
  39             }
  40         }
  41     }
  42
  43     flag_map
  44 }
  45
  46 fn not_ssa(flag_map: &mut IndexVec<Local, SsaKind>, local: Local) {
  47     flag_map[local] = SsaKind::NotSsa;
  48 }