src/librustc_mir/pretty.rs

   1 // Copyright 2014 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 rustc::hir;
  12 use rustc::hir::def_id::DefId;
  13 use rustc::mir::*;
  14 use rustc::mir::transform::MirSource;
  15 use rustc::ty::TyCtxt;
  16 use rustc_data_structures::fx::FxHashMap;
  17 use rustc_data_structures::indexed_vec::{Idx};
  18 use std::fmt::Display;
  19 use std::fs;
  20 use std::io::{self, Write};
  21 use std::path::{PathBuf, Path};
  22
  23 const INDENT: &'static str = "    ";
  24 /// Alignment for lining up comments following MIR statements
  25 const ALIGN: usize = 40;
  26
  27 /// If the session is properly configured, dumps a human-readable
  28 /// representation of the mir into:
  29 ///
  30 /// ```text
  31 /// rustc.node<node_id>.<pass_name>.<disambiguator>
  32 /// ```
  33 ///
  34 /// Output from this function is controlled by passing `-Z dump-mir=<filter>`,
  35 /// where `<filter>` takes the following forms:
  36 ///
  37 /// - `all` -- dump MIR for all fns, all passes, all everything
  38 /// - `substring1&substring2,...` -- `&`-separated list of substrings
  39 ///   that can appear in the pass-name or the `item_path_str` for the given
  40 ///   node-id. If any one of the substrings match, the data is dumped out.
  41 pub fn dump_mir<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
  42                           pass_name: &str,
  43                           disambiguator: &Display,
  44                           src: MirSource,
  45                           mir: &Mir<'tcx>) {
  46     let filters = match tcx.sess.opts.debugging_opts.dump_mir {
  47         None => return,
  48         Some(ref filters) => filters,
  49     };
  50     let node_id = src.item_id();
  51     let node_path = tcx.item_path_str(tcx.hir.local_def_id(node_id));
  52     let is_matched =
  53         filters.split("&")
  54                .any(|filter| {
  55                    filter == "all" ||
  56                        pass_name.contains(filter) ||
  57                        node_path.contains(filter)
  58                });
  59     if !is_matched {
  60         return;
  61     }
  62
  63     let promotion_id = match src {
  64         MirSource::Promoted(_, id) => format!("-{:?}", id),
  65         _ => String::new()
  66     };
  67
  68     let mut file_path = PathBuf::new();
  69     if let Some(ref file_dir) = tcx.sess.opts.debugging_opts.dump_mir_dir {
  70         let p = Path::new(file_dir);
  71         file_path.push(p);
  72     };
  73     let file_name = format!("rustc.node{}{}.{}.{}.mir",
  74                             node_id, promotion_id, pass_name, disambiguator);
  75     file_path.push(&file_name);
  76     let _ = fs::File::create(&file_path).and_then(|mut file| {
  77         writeln!(file, "// MIR for `{}`", node_path)?;
  78         writeln!(file, "// node_id = {}", node_id)?;
  79         writeln!(file, "// pass_name = {}", pass_name)?;
  80         writeln!(file, "// disambiguator = {}", disambiguator)?;
  81         writeln!(file, "")?;
  82         write_mir_fn(tcx, src, mir, &mut file)?;
  83         Ok(())
  84     });
  85 }
  86
  87 /// Write out a human-readable textual representation for the given MIR.
  88 pub fn write_mir_pretty<'a, 'b, 'tcx, I>(tcx: TyCtxt<'b, 'tcx, 'tcx>,
  89                                          iter: I,
  90                                          w: &mut Write)
  91                                          -> io::Result<()>
  92     where I: Iterator<Item=DefId>, 'tcx: 'a
  93 {
  94     let mut first = true;
  95     for def_id in iter.filter(DefId::is_local) {
  96         let mir = &tcx.item_mir(def_id);
  97
  98         if first {
  99             first = false;
 100         } else {
 101             // Put empty lines between all items
 102             writeln!(w, "")?;
 103         }
 104
 105         let id = tcx.hir.as_local_node_id(def_id).unwrap();
 106         let src = MirSource::from_node(tcx, id);
 107         write_mir_fn(tcx, src, mir, w)?;
 108
 109         for (i, mir) in mir.promoted.iter_enumerated() {
 110             writeln!(w, "")?;
 111             write_mir_fn(tcx, MirSource::Promoted(id, i), mir, w)?;
 112         }
 113     }
 114     Ok(())
 115 }
 116
 117 pub fn write_mir_fn<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 118                               src: MirSource,
 119                               mir: &Mir<'tcx>,
 120                               w: &mut Write)
 121                               -> io::Result<()> {
 122     write_mir_intro(tcx, src, mir, w)?;
 123     for block in mir.basic_blocks().indices() {
 124         write_basic_block(tcx, block, mir, w)?;
 125         if block.index() + 1 != mir.basic_blocks().len() {
 126             writeln!(w, "")?;
 127         }
 128     }
 129
 130     writeln!(w, "}}")?;
 131     Ok(())
 132 }
 133
 134 /// Write out a human-readable textual representation for the given basic block.
 135 fn write_basic_block(tcx: TyCtxt,
 136                      block: BasicBlock,
 137                      mir: &Mir,
 138                      w: &mut Write)
 139                      -> io::Result<()> {
 140     let data = &mir[block];
 141
 142     // Basic block label at the top.
 143     writeln!(w, "{}{:?}: {{", INDENT, block)?;
 144
 145     // List of statements in the middle.
 146     let mut current_location = Location { block: block, statement_index: 0 };
 147     for statement in &data.statements {
 148         let indented_mir = format!("{0}{0}{1:?};", INDENT, statement);
 149         writeln!(w, "{0:1$} // {2}",
 150                  indented_mir,
 151                  ALIGN,
 152                  comment(tcx, statement.source_info))?;
 153
 154         current_location.statement_index += 1;
 155     }
 156
 157     // Terminator at the bottom.
 158     let indented_terminator = format!("{0}{0}{1:?};", INDENT, data.terminator().kind);
 159     writeln!(w, "{0:1$} // {2}",
 160              indented_terminator,
 161              ALIGN,
 162              comment(tcx, data.terminator().source_info))?;
 163
 164     writeln!(w, "{}}}", INDENT)
 165 }
 166
 167 fn comment(tcx: TyCtxt, SourceInfo { span, scope }: SourceInfo) -> String {
 168     format!("scope {} at {}", scope.index(), tcx.sess.codemap().span_to_string(span))
 169 }
 170
 171 /// Prints user-defined variables in a scope tree.
 172 ///
 173 /// Returns the total number of variables printed.
 174 fn write_scope_tree(tcx: TyCtxt,
 175                     mir: &Mir,
 176                     scope_tree: &FxHashMap<VisibilityScope, Vec<VisibilityScope>>,
 177                     w: &mut Write,
 178                     parent: VisibilityScope,
 179                     depth: usize)
 180                     -> io::Result<()> {
 181     let indent = depth * INDENT.len();
 182
 183     let children = match scope_tree.get(&parent) {
 184         Some(childs) => childs,
 185         None => return Ok(()),
 186     };
 187
 188     for &child in children {
 189         let data = &mir.visibility_scopes[child];
 190         assert_eq!(data.parent_scope, Some(parent));
 191         writeln!(w, "{0:1$}scope {2} {{", "", indent, child.index())?;
 192
 193         // User variable types (including the user's name in a comment).
 194         for local in mir.vars_iter() {
 195             let var = &mir.local_decls[local];
 196             let (name, source_info) = if var.source_info.unwrap().scope == child {
 197                 (var.name.unwrap(), var.source_info.unwrap())
 198             } else {
 199                 // Not a variable or not declared in this scope.
 200                 continue;
 201             };
 202
 203             let mut_str = if var.mutability == Mutability::Mut {
 204                 "mut "
 205             } else {
 206                 ""
 207             };
 208
 209             let indent = indent + INDENT.len();
 210             let indented_var = format!("{0:1$}let {2}{3:?}: {4};",
 211                                        INDENT,
 212                                        indent,
 213                                        mut_str,
 214                                        local,
 215                                        var.ty);
 216             writeln!(w, "{0:1$} // \"{2}\" in {3}",
 217                      indented_var,
 218                      ALIGN,
 219                      name,
 220                      comment(tcx, source_info))?;
 221         }
 222
 223         write_scope_tree(tcx, mir, scope_tree, w, child, depth + 1)?;
 224
 225         writeln!(w, "{0:1$}}}", "", depth * INDENT.len())?;
 226     }
 227
 228     Ok(())
 229 }
 230
 231 /// Write out a human-readable textual representation of the MIR's `fn` type and the types of its
 232 /// local variables (both user-defined bindings and compiler temporaries).
 233 fn write_mir_intro<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 234                              src: MirSource,
 235                              mir: &Mir,
 236                              w: &mut Write)
 237                              -> io::Result<()> {
 238     write_mir_sig(tcx, src, mir, w)?;
 239     writeln!(w, " {{")?;
 240
 241     // construct a scope tree and write it out
 242     let mut scope_tree: FxHashMap<VisibilityScope, Vec<VisibilityScope>> = FxHashMap();
 243     for (index, scope_data) in mir.visibility_scopes.iter().enumerate() {
 244         if let Some(parent) = scope_data.parent_scope {
 245             scope_tree.entry(parent)
 246                       .or_insert(vec![])
 247                       .push(VisibilityScope::new(index));
 248         } else {
 249             // Only the argument scope has no parent, because it's the root.
 250             assert_eq!(index, ARGUMENT_VISIBILITY_SCOPE.index());
 251         }
 252     }
 253
 254     // Print return pointer
 255     let indented_retptr = format!("{}let mut {:?}: {};",
 256                                   INDENT,
 257                                   RETURN_POINTER,
 258                                   mir.return_ty);
 259     writeln!(w, "{0:1$} // return pointer",
 260              indented_retptr,
 261              ALIGN)?;
 262
 263     write_scope_tree(tcx, mir, &scope_tree, w, ARGUMENT_VISIBILITY_SCOPE, 1)?;
 264
 265     write_temp_decls(mir, w)?;
 266
 267     // Add an empty line before the first block is printed.
 268     writeln!(w, "")?;
 269
 270     Ok(())
 271 }
 272
 273 fn write_mir_sig(tcx: TyCtxt, src: MirSource, mir: &Mir, w: &mut Write)
 274                  -> io::Result<()>
 275 {
 276     match src {
 277         MirSource::Fn(_) => write!(w, "fn")?,
 278         MirSource::Const(_) => write!(w, "const")?,
 279         MirSource::Static(_, hir::MutImmutable) => write!(w, "static")?,
 280         MirSource::Static(_, hir::MutMutable) => write!(w, "static mut")?,
 281         MirSource::Promoted(_, i) => write!(w, "{:?} in", i)?
 282     }
 283
 284     write!(w, " {}", tcx.node_path_str(src.item_id()))?;
 285
 286     if let MirSource::Fn(_) = src {
 287         write!(w, "(")?;
 288
 289         // fn argument types.
 290         for (i, arg) in mir.args_iter().enumerate() {
 291             if i != 0 {
 292                 write!(w, ", ")?;
 293             }
 294             write!(w, "{:?}: {}", Lvalue::Local(arg), mir.local_decls[arg].ty)?;
 295         }
 296
 297         write!(w, ") -> {}", mir.return_ty)
 298     } else {
 299         assert_eq!(mir.arg_count, 0);
 300         write!(w, ": {} =", mir.return_ty)
 301     }
 302 }
 303
 304 fn write_temp_decls(mir: &Mir, w: &mut Write) -> io::Result<()> {
 305     // Compiler-introduced temporary types.
 306     for temp in mir.temps_iter() {
 307         writeln!(w, "{}let mut {:?}: {};", INDENT, temp, mir.local_decls[temp].ty)?;
 308     }
 309
 310     Ok(())
 311 }