src/librustc_mir/mir_map.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 //! An experimental pass that scources for `#[rustc_mir]` attributes,
  12 //! builds the resulting MIR, and dumps it out into a file for inspection.
  13 //!
  14 //! The attribute formats that are currently accepted are:
  15 //!
  16 //! - `#[rustc_mir(graphviz="file.gv")]`
  17 //! - `#[rustc_mir(pretty="file.mir")]`
  18
  19 extern crate syntax;
  20 extern crate rustc;
  21 extern crate rustc_front;
  22
  23 use build;
  24 use graphviz;
  25 use pretty;
  26 use transform::*;
  27 use rustc::mir::repr::Mir;
  28 use hair::cx::Cx;
  29 use std::fs::File;
  30
  31 use self::rustc::middle::infer;
  32 use self::rustc::middle::region::CodeExtentData;
  33 use self::rustc::middle::ty::{self, Ty};
  34 use self::rustc::util::common::ErrorReported;
  35 use self::rustc::util::nodemap::NodeMap;
  36 use self::rustc_front::hir;
  37 use self::rustc_front::intravisit::{self, Visitor};
  38 use self::syntax::ast;
  39 use self::syntax::attr::AttrMetaMethods;
  40 use self::syntax::codemap::Span;
  41
  42 pub type MirMap<'tcx> = NodeMap<Mir<'tcx>>;
  43
  44 pub fn build_mir_for_crate<'tcx>(tcx: &ty::ctxt<'tcx>) -> MirMap<'tcx> {
  45     let mut map = NodeMap();
  46     {
  47         let mut dump = OuterDump {
  48             tcx: tcx,
  49             map: &mut map,
  50         };
  51         tcx.map.krate().visit_all_items(&mut dump);
  52     }
  53     map
  54 }
  55
  56 ///////////////////////////////////////////////////////////////////////////
  57 // OuterDump -- walks a crate, looking for fn items and methods to build MIR from
  58
  59 struct OuterDump<'a, 'tcx: 'a> {
  60     tcx: &'a ty::ctxt<'tcx>,
  61     map: &'a mut MirMap<'tcx>,
  62 }
  63
  64 impl<'a, 'tcx> OuterDump<'a, 'tcx> {
  65     fn visit_mir<OP>(&mut self, attributes: &'a [ast::Attribute], mut walk_op: OP)
  66         where OP: for<'m> FnMut(&mut InnerDump<'a, 'm, 'tcx>)
  67     {
  68         let mut closure_dump = InnerDump {
  69             tcx: self.tcx,
  70             attr: None,
  71             map: &mut *self.map,
  72         };
  73         for attr in attributes {
  74             if attr.check_name("rustc_mir") {
  75                 closure_dump.attr = Some(attr);
  76             }
  77         }
  78         walk_op(&mut closure_dump);
  79     }
  80 }
  81
  82
  83 impl<'a, 'tcx> Visitor<'tcx> for OuterDump<'a, 'tcx> {
  84     fn visit_item(&mut self, item: &'tcx hir::Item) {
  85         self.visit_mir(&item.attrs, |c| intravisit::walk_item(c, item));
  86         intravisit::walk_item(self, item);
  87     }
  88
  89     fn visit_trait_item(&mut self, trait_item: &'tcx hir::TraitItem) {
  90         match trait_item.node {
  91             hir::MethodTraitItem(_, Some(_)) => {
  92                 self.visit_mir(&trait_item.attrs, |c| intravisit::walk_trait_item(c, trait_item));
  93             }
  94             hir::MethodTraitItem(_, None) |
  95             hir::ConstTraitItem(..) |
  96             hir::TypeTraitItem(..) => {}
  97         }
  98         intravisit::walk_trait_item(self, trait_item);
  99     }
 100
 101     fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem) {
 102         match impl_item.node {
 103             hir::ImplItemKind::Method(..) => {
 104                 self.visit_mir(&impl_item.attrs, |c| intravisit::walk_impl_item(c, impl_item));
 105             }
 106             hir::ImplItemKind::Const(..) | hir::ImplItemKind::Type(..) => {}
 107         }
 108         intravisit::walk_impl_item(self, impl_item);
 109     }
 110 }
 111
 112 ///////////////////////////////////////////////////////////////////////////
 113 // InnerDump -- dumps MIR for a single fn and its contained closures
 114
 115 struct InnerDump<'a, 'm, 'tcx: 'a + 'm> {
 116     tcx: &'a ty::ctxt<'tcx>,
 117     map: &'m mut MirMap<'tcx>,
 118     attr: Option<&'a ast::Attribute>,
 119 }
 120
 121 impl<'a, 'm, 'tcx> Visitor<'tcx> for InnerDump<'a,'m,'tcx> {
 122     fn visit_trait_item(&mut self, _: &'tcx hir::TraitItem) {
 123         // ignore methods; the outer dump will call us for them independently
 124     }
 125
 126     fn visit_impl_item(&mut self, _: &'tcx hir::ImplItem) {
 127         // ignore methods; the outer dump will call us for them independently
 128     }
 129
 130     fn visit_fn(&mut self,
 131                 fk: intravisit::FnKind<'tcx>,
 132                 decl: &'tcx hir::FnDecl,
 133                 body: &'tcx hir::Block,
 134                 span: Span,
 135                 id: ast::NodeId) {
 136         let (prefix, implicit_arg_tys) = match fk {
 137             intravisit::FnKind::Closure =>
 138                 (format!("{}-", id), vec![closure_self_ty(&self.tcx, id, body.id)]),
 139             _ =>
 140                 (format!(""), vec![]),
 141         };
 142
 143         let param_env = ty::ParameterEnvironment::for_item(self.tcx, id);
 144
 145         let infcx = infer::new_infer_ctxt(self.tcx, &self.tcx.tables, Some(param_env), true);
 146
 147         match build_mir(Cx::new(&infcx), implicit_arg_tys, id, span, decl, body) {
 148             Ok(mut mir) => {
 149                 simplify_cfg::SimplifyCfg::new().run_on_mir(&mut mir);
 150
 151                 let meta_item_list = self.attr
 152                                          .iter()
 153                                          .flat_map(|a| a.meta_item_list())
 154                                          .flat_map(|l| l.iter());
 155                 for item in meta_item_list {
 156                     if item.check_name("graphviz") || item.check_name("pretty") {
 157                         match item.value_str() {
 158                             Some(s) => {
 159                                 let filename = format!("{}{}", prefix, s);
 160                                 let result = File::create(&filename).and_then(|ref mut output| {
 161                                     if item.check_name("graphviz") {
 162                                         graphviz::write_mir_graphviz(&mir, output)
 163                                     } else {
 164                                         pretty::write_mir_pretty(&mir, output)
 165                                     }
 166                                 });
 167
 168                                 if let Err(e) = result {
 169                                     self.tcx.sess.span_fatal(
 170                                         item.span,
 171                                         &format!("Error writing MIR {} results to `{}`: {}",
 172                                                  item.name(), filename, e));
 173                                 }
 174                             }
 175                             None => {
 176                                 self.tcx.sess.span_err(
 177                                     item.span,
 178                                     &format!("{} attribute requires a path", item.name()));
 179                             }
 180                         }
 181                     }
 182                 }
 183
 184                 let previous = self.map.insert(id, mir);
 185                 assert!(previous.is_none());
 186             }
 187             Err(ErrorReported) => {}
 188         }
 189
 190         intravisit::walk_fn(self, fk, decl, body, span);
 191     }
 192 }
 193
 194 fn build_mir<'a,'tcx:'a>(cx: Cx<'a,'tcx>,
 195                          implicit_arg_tys: Vec<Ty<'tcx>>,
 196                          fn_id: ast::NodeId,
 197                          span: Span,
 198                          decl: &'tcx hir::FnDecl,
 199                          body: &'tcx hir::Block)
 200                          -> Result<Mir<'tcx>, ErrorReported> {
 201     // fetch the fully liberated fn signature (that is, all bound
 202     // types/lifetimes replaced)
 203     let fn_sig = match cx.tcx().tables.borrow().liberated_fn_sigs.get(&fn_id) {
 204         Some(f) => f.clone(),
 205         None => {
 206             cx.tcx().sess.span_bug(span,
 207                                    &format!("no liberated fn sig for {:?}", fn_id));
 208         }
 209     };
 210
 211     let arguments =
 212         decl.inputs
 213             .iter()
 214             .enumerate()
 215             .map(|(index, arg)| {
 216                 (fn_sig.inputs[index], &*arg.pat)
 217             })
 218             .collect();
 219
 220     let parameter_scope =
 221         cx.tcx().region_maps.lookup_code_extent(
 222             CodeExtentData::ParameterScope { fn_id: fn_id, body_id: body.id });
 223     Ok(build::construct(cx,
 224                         span,
 225                         implicit_arg_tys,
 226                         arguments,
 227                         parameter_scope,
 228                         fn_sig.output,
 229                         body))
 230 }
 231
 232 fn closure_self_ty<'a, 'tcx>(tcx: &ty::ctxt<'tcx>,
 233                              closure_expr_id: ast::NodeId,
 234                              body_id: ast::NodeId)
 235                              -> Ty<'tcx> {
 236     let closure_ty = tcx.node_id_to_type(closure_expr_id);
 237
 238     // We're just hard-coding the idea that the signature will be
 239     // &self or &mut self and hence will have a bound region with
 240     // number 0, hokey.
 241     let region = ty::Region::ReFree(ty::FreeRegion {
 242         scope: tcx.region_maps.item_extent(body_id),
 243         bound_region: ty::BoundRegion::BrAnon(0),
 244     });
 245     let region = tcx.mk_region(region);
 246
 247     match tcx.closure_kind(tcx.map.local_def_id(closure_expr_id)) {
 248         ty::ClosureKind::FnClosureKind =>
 249             tcx.mk_ref(region,
 250                        ty::TypeAndMut { ty: closure_ty,
 251                                         mutbl: hir::MutImmutable }),
 252         ty::ClosureKind::FnMutClosureKind =>
 253             tcx.mk_ref(region,
 254                        ty::TypeAndMut { ty: closure_ty,
 255                                         mutbl: hir::MutMutable }),
 256         ty::ClosureKind::FnOnceClosureKind =>
 257             closure_ty
 258     }
 259 }