src/librustc_mir/util/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, LOCAL_CRATE};
  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_num>.<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_num: usize,
  43                           pass_name: &str,
  44                           disambiguator: &Display,
  45                           source: MirSource,
  46                           mir: &Mir<'tcx>) {
  47     let filters = match tcx.sess.opts.debugging_opts.dump_mir {
  48         None => return,
  49         Some(ref filters) => filters,
  50     };
  51     let node_id = source.item_id();
  52     let node_path = tcx.item_path_str(tcx.hir.local_def_id(node_id));
  53     let is_matched =
  54         filters.split("&")
  55                .any(|filter| {
  56                    filter == "all" ||
  57                        pass_name.contains(filter) ||
  58                        node_path.contains(filter)
  59                });
  60     if !is_matched {
  61         return;
  62     }
  63
  64     dump_matched_mir_node(tcx, pass_num, pass_name, &node_path, disambiguator, source, mir);
  65     for (index, promoted_mir) in mir.promoted.iter_enumerated() {
  66         let promoted_source = MirSource::Promoted(source.item_id(), index);
  67         dump_matched_mir_node(tcx, pass_num, pass_name, &node_path, disambiguator,
  68                               promoted_source, promoted_mir);
  69     }
  70 }
  71
  72 fn dump_matched_mir_node<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
  73                                    pass_num: usize,
  74                                    pass_name: &str,
  75                                    node_path: &str,
  76                                    disambiguator: &Display,
  77                                    source: MirSource,
  78                                    mir: &Mir<'tcx>) {
  79     let promotion_id = match source {
  80         MirSource::Promoted(_, id) => format!("-{:?}", id),
  81         _ => String::new()
  82     };
  83
  84     let pass_num = if tcx.sess.opts.debugging_opts.dump_mir_exclude_pass_number {
  85         format!("")
  86     } else {
  87         format!(".{:03}", pass_num)
  88     };
  89
  90     let mut file_path = PathBuf::new();
  91     if let Some(ref file_dir) = tcx.sess.opts.debugging_opts.dump_mir_dir {
  92         let p = Path::new(file_dir);
  93         file_path.push(p);
  94     };
  95     let file_name = format!("rustc.node{}{}{}.{}.{}.mir",
  96                             source.item_id(), promotion_id, pass_num, pass_name, disambiguator);
  97     file_path.push(&file_name);
  98     let _ = fs::File::create(&file_path).and_then(|mut file| {
  99         writeln!(file, "// MIR for `{}`", node_path)?;
 100         writeln!(file, "// source = {:?}", source)?;
 101         writeln!(file, "// pass_name = {}", pass_name)?;
 102         writeln!(file, "// disambiguator = {}", disambiguator)?;
 103         writeln!(file, "")?;
 104         write_mir_fn(tcx, source, mir, &mut file)?;
 105         Ok(())
 106     });
 107 }
 108
 109 /// Write out a human-readable textual representation for the given MIR.
 110 pub fn write_mir_pretty<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 111                                   single: Option<DefId>,
 112                                   w: &mut Write)
 113                                   -> io::Result<()>
 114 {
 115     writeln!(w, "// WARNING: This output format is intended for human consumers only")?;
 116     writeln!(w, "// and is subject to change without notice. Knock yourself out.")?;
 117
 118     let mut first = true;
 119     for def_id in dump_mir_def_ids(tcx, single) {
 120         let mir = &tcx.item_mir(def_id);
 121
 122         if first {
 123             first = false;
 124         } else {
 125             // Put empty lines between all items
 126             writeln!(w, "")?;
 127         }
 128
 129         let id = tcx.hir.as_local_node_id(def_id).unwrap();
 130         let src = MirSource::from_node(tcx, id);
 131         write_mir_fn(tcx, src, mir, w)?;
 132
 133         for (i, mir) in mir.promoted.iter_enumerated() {
 134             writeln!(w, "")?;
 135             write_mir_fn(tcx, MirSource::Promoted(id, i), mir, w)?;
 136         }
 137     }
 138     Ok(())
 139 }
 140
 141 pub fn write_mir_fn<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 142                               src: MirSource,
 143                               mir: &Mir<'tcx>,
 144                               w: &mut Write)
 145                               -> io::Result<()> {
 146     write_mir_intro(tcx, src, mir, w)?;
 147     for block in mir.basic_blocks().indices() {
 148         write_basic_block(tcx, block, mir, w)?;
 149         if block.index() + 1 != mir.basic_blocks().len() {
 150             writeln!(w, "")?;
 151         }
 152     }
 153
 154     writeln!(w, "}}")?;
 155     Ok(())
 156 }
 157
 158 /// Write out a human-readable textual representation for the given basic block.
 159 fn write_basic_block(tcx: TyCtxt,
 160                      block: BasicBlock,
 161                      mir: &Mir,
 162                      w: &mut Write)
 163                      -> io::Result<()> {
 164     let data = &mir[block];
 165
 166     // Basic block label at the top.
 167     writeln!(w, "{}{:?}: {{", INDENT, block)?;
 168
 169     // List of statements in the middle.
 170     let mut current_location = Location { block: block, statement_index: 0 };
 171     for statement in &data.statements {
 172         let indented_mir = format!("{0}{0}{1:?};", INDENT, statement);
 173         writeln!(w, "{0:1$} // {2}",
 174                  indented_mir,
 175                  ALIGN,
 176                  comment(tcx, statement.source_info))?;
 177
 178         current_location.statement_index += 1;
 179     }
 180
 181     // Terminator at the bottom.
 182     let indented_terminator = format!("{0}{0}{1:?};", INDENT, data.terminator().kind);
 183     writeln!(w, "{0:1$} // {2}",
 184              indented_terminator,
 185              ALIGN,
 186              comment(tcx, data.terminator().source_info))?;
 187
 188     writeln!(w, "{}}}", INDENT)
 189 }
 190
 191 fn comment(tcx: TyCtxt, SourceInfo { span, scope }: SourceInfo) -> String {
 192     format!("scope {} at {}", scope.index(), tcx.sess.codemap().span_to_string(span))
 193 }
 194
 195 /// Prints user-defined variables in a scope tree.
 196 ///
 197 /// Returns the total number of variables printed.
 198 fn write_scope_tree(tcx: TyCtxt,
 199                     mir: &Mir,
 200                     scope_tree: &FxHashMap<VisibilityScope, Vec<VisibilityScope>>,
 201                     w: &mut Write,
 202                     parent: VisibilityScope,
 203                     depth: usize)
 204                     -> io::Result<()> {
 205     let indent = depth * INDENT.len();
 206
 207     let children = match scope_tree.get(&parent) {
 208         Some(childs) => childs,
 209         None => return Ok(()),
 210     };
 211
 212     for &child in children {
 213         let data = &mir.visibility_scopes[child];
 214         assert_eq!(data.parent_scope, Some(parent));
 215         writeln!(w, "{0:1$}scope {2} {{", "", indent, child.index())?;
 216
 217         // User variable types (including the user's name in a comment).
 218         for local in mir.vars_iter() {
 219             let var = &mir.local_decls[local];
 220             let (name, source_info) = if var.source_info.scope == child {
 221                 (var.name.unwrap(), var.source_info)
 222             } else {
 223                 // Not a variable or not declared in this scope.
 224                 continue;
 225             };
 226
 227             let mut_str = if var.mutability == Mutability::Mut {
 228                 "mut "
 229             } else {
 230                 ""
 231             };
 232
 233             let indent = indent + INDENT.len();
 234             let indented_var = format!("{0:1$}let {2}{3:?}: {4};",
 235                                        INDENT,
 236                                        indent,
 237                                        mut_str,
 238                                        local,
 239                                        var.ty);
 240             writeln!(w, "{0:1$} // \"{2}\" in {3}",
 241                      indented_var,
 242                      ALIGN,
 243                      name,
 244                      comment(tcx, source_info))?;
 245         }
 246
 247         write_scope_tree(tcx, mir, scope_tree, w, child, depth + 1)?;
 248
 249         writeln!(w, "{0:1$}}}", "", depth * INDENT.len())?;
 250     }
 251
 252     Ok(())
 253 }
 254
 255 /// Write out a human-readable textual representation of the MIR's `fn` type and the types of its
 256 /// local variables (both user-defined bindings and compiler temporaries).
 257 fn write_mir_intro<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 258                              src: MirSource,
 259                              mir: &Mir,
 260                              w: &mut Write)
 261                              -> io::Result<()> {
 262     write_mir_sig(tcx, src, mir, w)?;
 263     writeln!(w, " {{")?;
 264
 265     // construct a scope tree and write it out
 266     let mut scope_tree: FxHashMap<VisibilityScope, Vec<VisibilityScope>> = FxHashMap();
 267     for (index, scope_data) in mir.visibility_scopes.iter().enumerate() {
 268         if let Some(parent) = scope_data.parent_scope {
 269             scope_tree.entry(parent)
 270                       .or_insert(vec![])
 271                       .push(VisibilityScope::new(index));
 272         } else {
 273             // Only the argument scope has no parent, because it's the root.
 274             assert_eq!(index, ARGUMENT_VISIBILITY_SCOPE.index());
 275         }
 276     }
 277
 278     // Print return pointer
 279     let indented_retptr = format!("{}let mut {:?}: {};",
 280                                   INDENT,
 281                                   RETURN_POINTER,
 282                                   mir.return_ty);
 283     writeln!(w, "{0:1$} // return pointer",
 284              indented_retptr,
 285              ALIGN)?;
 286
 287     write_scope_tree(tcx, mir, &scope_tree, w, ARGUMENT_VISIBILITY_SCOPE, 1)?;
 288
 289     write_temp_decls(mir, w)?;
 290
 291     // Add an empty line before the first block is printed.
 292     writeln!(w, "")?;
 293
 294     Ok(())
 295 }
 296
 297 fn write_mir_sig(tcx: TyCtxt, src: MirSource, mir: &Mir, w: &mut Write)
 298                  -> io::Result<()>
 299 {
 300     match src {
 301         MirSource::Fn(_) => write!(w, "fn")?,
 302         MirSource::Const(_) => write!(w, "const")?,
 303         MirSource::Static(_, hir::MutImmutable) => write!(w, "static")?,
 304         MirSource::Static(_, hir::MutMutable) => write!(w, "static mut")?,
 305         MirSource::Promoted(_, i) => write!(w, "{:?} in", i)?
 306     }
 307
 308     write!(w, " {}", tcx.node_path_str(src.item_id()))?;
 309
 310     if let MirSource::Fn(_) = src {
 311         write!(w, "(")?;
 312
 313         // fn argument types.
 314         for (i, arg) in mir.args_iter().enumerate() {
 315             if i != 0 {
 316                 write!(w, ", ")?;
 317             }
 318             write!(w, "{:?}: {}", Lvalue::Local(arg), mir.local_decls[arg].ty)?;
 319         }
 320
 321         write!(w, ") -> {}", mir.return_ty)
 322     } else {
 323         assert_eq!(mir.arg_count, 0);
 324         write!(w, ": {} =", mir.return_ty)
 325     }
 326 }
 327
 328 fn write_temp_decls(mir: &Mir, w: &mut Write) -> io::Result<()> {
 329     // Compiler-introduced temporary types.
 330     for temp in mir.temps_iter() {
 331         writeln!(w, "{}let mut {:?}: {};", INDENT, temp, mir.local_decls[temp].ty)?;
 332     }
 333
 334     Ok(())
 335 }
 336
 337 pub fn dump_mir_def_ids(tcx: TyCtxt, single: Option<DefId>) -> Vec<DefId> {
 338     if let Some(i) = single {
 339         vec![i]
 340     } else {
 341         tcx.mir_keys(LOCAL_CRATE).iter().cloned().collect()
 342     }
 343 }