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