src/librustc_mir/transform/mod.rs

   1 // Copyright 2015 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 use build;
  12 use rustc::hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
  13 use rustc::mir::Mir;
  14 use rustc::mir::transform::{MirPassIndex, MirSuite, MirSource,
  15                             MIR_CONST, MIR_VALIDATED, MIR_OPTIMIZED};
  16 use rustc::ty::{self, TyCtxt};
  17 use rustc::ty::maps::Providers;
  18 use rustc::ty::steal::Steal;
  19 use rustc::hir;
  20 use rustc::hir::intravisit::{self, Visitor, NestedVisitorMap};
  21 use rustc::util::nodemap::DefIdSet;
  22 use std::rc::Rc;
  23 use syntax::ast;
  24 use syntax_pos::{DUMMY_SP, Span};
  25 use transform;
  26
  27 pub mod clean_end_regions;
  28 pub mod simplify_branches;
  29 pub mod simplify;
  30 pub mod erase_regions;
  31 pub mod no_landing_pads;
  32 pub mod type_check;
  33 pub mod rustc_peek;
  34 pub mod elaborate_drops;
  35 pub mod add_call_guards;
  36 pub mod promote_consts;
  37 pub mod qualify_consts;
  38 pub mod dump_mir;
  39 pub mod deaggregator;
  40 pub mod instcombine;
  41 pub mod copy_prop;
  42 pub mod inline;
  43
  44 pub(crate) fn provide(providers: &mut Providers) {
  45     self::qualify_consts::provide(providers);
  46     *providers = Providers {
  47         mir_keys,
  48         mir_const,
  49         mir_validated,
  50         optimized_mir,
  51         is_mir_available,
  52         ..*providers
  53     };
  54 }
  55
  56 fn is_mir_available<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> bool {
  57     tcx.mir_keys(def_id.krate).contains(&def_id)
  58 }
  59
  60 /// Finds the full set of def-ids within the current crate that have
  61 /// MIR associated with them.
  62 fn mir_keys<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, krate: CrateNum)
  63                       -> Rc<DefIdSet> {
  64     assert_eq!(krate, LOCAL_CRATE);
  65
  66     let mut set = DefIdSet();
  67
  68     // All body-owners have MIR associated with them.
  69     set.extend(tcx.body_owners());
  70
  71     // Additionally, tuple struct/variant constructors have MIR, but
  72     // they don't have a BodyId, so we need to build them separately.
  73     struct GatherCtors<'a, 'tcx: 'a> {
  74         tcx: TyCtxt<'a, 'tcx, 'tcx>,
  75         set: &'a mut DefIdSet,
  76     }
  77     impl<'a, 'tcx> Visitor<'tcx> for GatherCtors<'a, 'tcx> {
  78         fn visit_variant_data(&mut self,
  79                               v: &'tcx hir::VariantData,
  80                               _: ast::Name,
  81                               _: &'tcx hir::Generics,
  82                               _: ast::NodeId,
  83                               _: Span) {
  84             if let hir::VariantData::Tuple(_, node_id) = *v {
  85                 self.set.insert(self.tcx.hir.local_def_id(node_id));
  86             }
  87             intravisit::walk_struct_def(self, v)
  88         }
  89         fn nested_visit_map<'b>(&'b mut self) -> NestedVisitorMap<'b, 'tcx> {
  90             NestedVisitorMap::None
  91         }
  92     }
  93     tcx.hir.krate().visit_all_item_likes(&mut GatherCtors {
  94         tcx: tcx,
  95         set: &mut set,
  96     }.as_deep_visitor());
  97
  98     Rc::new(set)
  99 }
 100
 101 fn mir_const<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> &'tcx Steal<Mir<'tcx>> {
 102     let mut mir = build::mir_build(tcx, def_id);
 103     let source = MirSource::from_local_def_id(tcx, def_id);
 104     transform::run_suite(tcx, source, MIR_CONST, &mut mir);
 105     tcx.alloc_steal_mir(mir)
 106 }
 107
 108 fn mir_validated<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> &'tcx Steal<Mir<'tcx>> {
 109     let source = MirSource::from_local_def_id(tcx, def_id);
 110     if let MirSource::Const(_) = source {
 111         // Ensure that we compute the `mir_const_qualif` for constants at
 112         // this point, before we steal the mir-const result. We don't
 113         // directly need the result or `mir_const_qualif`, so we can just force it.
 114         ty::queries::mir_const_qualif::force(tcx, DUMMY_SP, def_id);
 115     }
 116
 117     let mut mir = tcx.mir_const(def_id).steal();
 118     transform::run_suite(tcx, source, MIR_VALIDATED, &mut mir);
 119     tcx.alloc_steal_mir(mir)
 120 }
 121
 122 fn optimized_mir<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> &'tcx Mir<'tcx> {
 123     // Borrowck uses `mir_validated`, so we have to force it to
 124     // execute before we can steal.
 125     ty::queries::borrowck::force(tcx, DUMMY_SP, def_id);
 126
 127     let mut mir = tcx.mir_validated(def_id).steal();
 128     let source = MirSource::from_local_def_id(tcx, def_id);
 129     transform::run_suite(tcx, source, MIR_OPTIMIZED, &mut mir);
 130     tcx.alloc_mir(mir)
 131 }
 132
 133 fn run_suite<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 134                        source: MirSource,
 135                        suite: MirSuite,
 136                        mir: &mut Mir<'tcx>)
 137 {
 138     let passes = tcx.mir_passes.passes(suite);
 139
 140     for (pass, index) in passes.iter().zip(0..) {
 141         let pass_num = MirPassIndex(index);
 142
 143         for hook in tcx.mir_passes.hooks() {
 144             hook.on_mir_pass(tcx, suite, pass_num, &pass.name(), source, &mir, false);
 145         }
 146
 147         pass.run_pass(tcx, source, mir);
 148
 149         for hook in tcx.mir_passes.hooks() {
 150             hook.on_mir_pass(tcx, suite, pass_num, &pass.name(), source, &mir, true);
 151         }
 152     }
 153 }