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::{MirSuite, MirPassIndex, MirSource};
  15 use rustc::ty::TyCtxt;
  16 use rustc::ty::item_path;
  17 use rustc_data_structures::fx::FxHashMap;
  18 use rustc_data_structures::indexed_vec::{Idx};
  19 use std::fmt::Display;
  20 use std::fs;
  21 use std::io::{self, Write};
  22 use std::path::{PathBuf, Path};
  23
  24 const INDENT: &'static str = "    ";
  25 /// Alignment for lining up comments following MIR statements
  26 const ALIGN: usize = 40;
  27
  28 /// If the session is properly configured, dumps a human-readable
  29 /// representation of the mir into:
  30 ///
  31 /// ```text
  32 /// rustc.node<node_id>.<pass_num>.<pass_name>.<disambiguator>
  33 /// ```
  34 ///
  35 /// Output from this function is controlled by passing `-Z dump-mir=<filter>`,
  36 /// where `<filter>` takes the following forms:
  37 ///
  38 /// - `all` -- dump MIR for all fns, all passes, all everything
  39 /// - `substring1&substring2,...` -- `&`-separated list of substrings
  40 ///   that can appear in the pass-name or the `item_path_str` for the given
  41 ///   node-id. If any one of the substrings match, the data is dumped out.
  42 pub fn dump_mir<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
  43                           pass_num: Option<(MirSuite, MirPassIndex)>,
  44                           pass_name: &str,
  45                           disambiguator: &Display,
  46                           source: MirSource,
  47                           mir: &Mir<'tcx>) {
  48     if !dump_enabled(tcx, pass_name, source) {
  49         return;
  50     }
  51
  52     let node_path = item_path::with_forced_impl_filename_line(|| { // see notes on #41697 below
  53         tcx.item_path_str(tcx.hir.local_def_id(source.item_id()))
  54     });
  55     dump_matched_mir_node(tcx, pass_num, pass_name, &node_path,
  56                           disambiguator, source, mir);
  57     for (index, promoted_mir) in mir.promoted.iter_enumerated() {
  58         let promoted_source = MirSource::Promoted(source.item_id(), index);
  59         dump_matched_mir_node(tcx, pass_num, pass_name, &node_path, disambiguator,
  60                               promoted_source, promoted_mir);
  61     }
  62 }
  63
  64 pub fn dump_enabled<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
  65                               pass_name: &str,
  66                               source: MirSource)
  67                               -> bool {
  68     let filters = match tcx.sess.opts.debugging_opts.dump_mir {
  69         None => return false,
  70         Some(ref filters) => filters,
  71     };
  72     let node_id = source.item_id();
  73     let node_path = item_path::with_forced_impl_filename_line(|| { // see notes on #41697 below
  74         tcx.item_path_str(tcx.hir.local_def_id(node_id))
  75     });
  76     filters.split("&")
  77            .any(|filter| {
  78                filter == "all" ||
  79                    pass_name.contains(filter) ||
  80                    node_path.contains(filter)
  81            })
  82 }
  83
  84 // #41697 -- we use `with_forced_impl_filename_line()` because
  85 // `item_path_str()` would otherwise trigger `type_of`, and this can
  86 // run while we are already attempting to evaluate `type_of`.
  87
  88 fn dump_matched_mir_node<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
  89                                    pass_num: Option<(MirSuite, MirPassIndex)>,
  90                                    pass_name: &str,
  91                                    node_path: &str,
  92                                    disambiguator: &Display,
  93                                    source: MirSource,
  94                                    mir: &Mir<'tcx>) {
  95     let promotion_id = match source {
  96         MirSource::Promoted(_, id) => format!("-{:?}", id),
  97         _ => String::new()
  98     };
  99
 100     let pass_num = if tcx.sess.opts.debugging_opts.dump_mir_exclude_pass_number {
 101         format!("")
 102     } else {
 103         match pass_num {
 104             None => format!(".-------"),
 105             Some((suite, pass_num)) => format!(".{:03}-{:03}", suite.0, pass_num.0),
 106         }
 107     };
 108
 109     let mut file_path = PathBuf::new();
 110     if let Some(ref file_dir) = tcx.sess.opts.debugging_opts.dump_mir_dir {
 111         let p = Path::new(file_dir);
 112         file_path.push(p);
 113     };
 114     let _ = fs::create_dir_all(&file_path);
 115     let file_name = format!("rustc.node{}{}{}.{}.{}.mir",
 116                             source.item_id(), promotion_id, pass_num, pass_name, disambiguator);
 117     file_path.push(&file_name);
 118     let _ = fs::File::create(&file_path).and_then(|mut file| {
 119         writeln!(file, "// MIR for `{}`", node_path)?;
 120         writeln!(file, "// source = {:?}", source)?;
 121         writeln!(file, "// pass_name = {}", pass_name)?;
 122         writeln!(file, "// disambiguator = {}", disambiguator)?;
 123         writeln!(file, "")?;
 124         write_mir_fn(tcx, source, mir, &mut file)?;
 125         Ok(())
 126     });
 127 }
 128
 129 /// Write out a human-readable textual representation for the given MIR.
 130 pub fn write_mir_pretty<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 131                                   single: Option<DefId>,
 132                                   w: &mut Write)
 133                                   -> io::Result<()>
 134 {
 135     writeln!(w, "// WARNING: This output format is intended for human consumers only")?;
 136     writeln!(w, "// and is subject to change without notice. Knock yourself out.")?;
 137
 138     let mut first = true;
 139     for def_id in dump_mir_def_ids(tcx, single) {
 140         let mir = &tcx.optimized_mir(def_id);
 141
 142         if first {
 143             first = false;
 144         } else {
 145             // Put empty lines between all items
 146             writeln!(w, "")?;
 147         }
 148
 149         let id = tcx.hir.as_local_node_id(def_id).unwrap();
 150         let src = MirSource::from_node(tcx, id);
 151         write_mir_fn(tcx, src, mir, w)?;
 152
 153         for (i, mir) in mir.promoted.iter_enumerated() {
 154             writeln!(w, "")?;
 155             write_mir_fn(tcx, MirSource::Promoted(id, i), mir, w)?;
 156         }
 157     }
 158     Ok(())
 159 }
 160
 161 pub fn write_mir_fn<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 162                               src: MirSource,
 163                               mir: &Mir<'tcx>,
 164                               w: &mut Write)
 165                               -> io::Result<()> {
 166     write_mir_intro(tcx, src, mir, w)?;
 167     for block in mir.basic_blocks().indices() {
 168         write_basic_block(tcx, block, mir, w)?;
 169         if block.index() + 1 != mir.basic_blocks().len() {
 170             writeln!(w, "")?;
 171         }
 172     }
 173
 174     writeln!(w, "}}")?;
 175     Ok(())
 176 }
 177
 178 /// Write out a human-readable textual representation for the given basic block.
 179 fn write_basic_block(tcx: TyCtxt,
 180                      block: BasicBlock,
 181                      mir: &Mir,
 182                      w: &mut Write)
 183                      -> io::Result<()> {
 184     let data = &mir[block];
 185
 186     // Basic block label at the top.
 187     writeln!(w, "{}{:?}: {{", INDENT, block)?;
 188
 189     // List of statements in the middle.
 190     let mut current_location = Location { block: block, statement_index: 0 };
 191     for statement in &data.statements {
 192         let indented_mir = format!("{0}{0}{1:?};", INDENT, statement);
 193         writeln!(w, "{0:1$} // {2}",
 194                  indented_mir,
 195                  ALIGN,
 196                  comment(tcx, statement.source_info))?;
 197
 198         current_location.statement_index += 1;
 199     }
 200
 201     // Terminator at the bottom.
 202     let indented_terminator = format!("{0}{0}{1:?};", INDENT, data.terminator().kind);
 203     writeln!(w, "{0:1$} // {2}",
 204              indented_terminator,
 205              ALIGN,
 206              comment(tcx, data.terminator().source_info))?;
 207
 208     writeln!(w, "{}}}", INDENT)
 209 }
 210
 211 fn comment(tcx: TyCtxt, SourceInfo { span, scope }: SourceInfo) -> String {
 212     format!("scope {} at {}", scope.index(), tcx.sess.codemap().span_to_string(span))
 213 }
 214
 215 /// Prints user-defined variables in a scope tree.
 216 ///
 217 /// Returns the total number of variables printed.
 218 fn write_scope_tree(tcx: TyCtxt,
 219                     mir: &Mir,
 220                     scope_tree: &FxHashMap<VisibilityScope, Vec<VisibilityScope>>,
 221                     w: &mut Write,
 222                     parent: VisibilityScope,
 223                     depth: usize)
 224                     -> io::Result<()> {
 225     let indent = depth * INDENT.len();
 226
 227     let children = match scope_tree.get(&parent) {
 228         Some(childs) => childs,
 229         None => return Ok(()),
 230     };
 231
 232     for &child in children {
 233         let data = &mir.visibility_scopes[child];
 234         assert_eq!(data.parent_scope, Some(parent));
 235         writeln!(w, "{0:1$}scope {2} {{", "", indent, child.index())?;
 236
 237         // User variable types (including the user's name in a comment).
 238         for local in mir.vars_iter() {
 239             let var = &mir.local_decls[local];
 240             let (name, source_info) = if var.source_info.scope == child {
 241                 (var.name.unwrap(), var.source_info)
 242             } else {
 243                 // Not a variable or not declared in this scope.
 244                 continue;
 245             };
 246
 247             let mut_str = if var.mutability == Mutability::Mut {
 248                 "mut "
 249             } else {
 250                 ""
 251             };
 252
 253             let indent = indent + INDENT.len();
 254             let indented_var = format!("{0:1$}let {2}{3:?}: {4};",
 255                                        INDENT,
 256                                        indent,
 257                                        mut_str,
 258                                        local,
 259                                        var.ty);
 260             writeln!(w, "{0:1$} // \"{2}\" in {3}",
 261                      indented_var,
 262                      ALIGN,
 263                      name,
 264                      comment(tcx, source_info))?;
 265         }
 266
 267         write_scope_tree(tcx, mir, scope_tree, w, child, depth + 1)?;
 268
 269         writeln!(w, "{0:1$}}}", "", depth * INDENT.len())?;
 270     }
 271
 272     Ok(())
 273 }
 274
 275 /// Write out a human-readable textual representation of the MIR's `fn` type and the types of its
 276 /// local variables (both user-defined bindings and compiler temporaries).
 277 fn write_mir_intro<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 278                              src: MirSource,
 279                              mir: &Mir,
 280                              w: &mut Write)
 281                              -> io::Result<()> {
 282     write_mir_sig(tcx, src, mir, w)?;
 283     writeln!(w, " {{")?;
 284
 285     // construct a scope tree and write it out
 286     let mut scope_tree: FxHashMap<VisibilityScope, Vec<VisibilityScope>> = FxHashMap();
 287     for (index, scope_data) in mir.visibility_scopes.iter().enumerate() {
 288         if let Some(parent) = scope_data.parent_scope {
 289             scope_tree.entry(parent)
 290                       .or_insert(vec![])
 291                       .push(VisibilityScope::new(index));
 292         } else {
 293             // Only the argument scope has no parent, because it's the root.
 294             assert_eq!(index, ARGUMENT_VISIBILITY_SCOPE.index());
 295         }
 296     }
 297
 298     // Print return pointer
 299     let indented_retptr = format!("{}let mut {:?}: {};",
 300                                   INDENT,
 301                                   RETURN_POINTER,
 302                                   mir.return_ty);
 303     writeln!(w, "{0:1$} // return pointer",
 304              indented_retptr,
 305              ALIGN)?;
 306
 307     write_scope_tree(tcx, mir, &scope_tree, w, ARGUMENT_VISIBILITY_SCOPE, 1)?;
 308
 309     write_temp_decls(mir, w)?;
 310
 311     // Add an empty line before the first block is printed.
 312     writeln!(w, "")?;
 313
 314     Ok(())
 315 }
 316
 317 fn write_mir_sig(tcx: TyCtxt, src: MirSource, mir: &Mir, w: &mut Write)
 318                  -> io::Result<()>
 319 {
 320     match src {
 321         MirSource::Fn(_) => write!(w, "fn")?,
 322         MirSource::Const(_) => write!(w, "const")?,
 323         MirSource::Static(_, hir::MutImmutable) => write!(w, "static")?,
 324         MirSource::Static(_, hir::MutMutable) => write!(w, "static mut")?,
 325         MirSource::Promoted(_, i) => write!(w, "{:?} in", i)?
 326     }
 327
 328     item_path::with_forced_impl_filename_line(|| { // see notes on #41697 elsewhere
 329         write!(w, " {}", tcx.node_path_str(src.item_id()))
 330     })?;
 331
 332     if let MirSource::Fn(_) = src {
 333         write!(w, "(")?;
 334
 335         // fn argument types.
 336         for (i, arg) in mir.args_iter().enumerate() {
 337             if i != 0 {
 338                 write!(w, ", ")?;
 339             }
 340             write!(w, "{:?}: {}", Lvalue::Local(arg), mir.local_decls[arg].ty)?;
 341         }
 342
 343         write!(w, ") -> {}", mir.return_ty)
 344     } else {
 345         assert_eq!(mir.arg_count, 0);
 346         write!(w, ": {} =", mir.return_ty)
 347     }
 348 }
 349
 350 fn write_temp_decls(mir: &Mir, w: &mut Write) -> io::Result<()> {
 351     // Compiler-introduced temporary types.
 352     for temp in mir.temps_iter() {
 353         writeln!(w, "{}let mut {:?}: {};", INDENT, temp, mir.local_decls[temp].ty)?;
 354     }
 355
 356     Ok(())
 357 }
 358
 359 pub fn dump_mir_def_ids(tcx: TyCtxt, single: Option<DefId>) -> Vec<DefId> {
 360     if let Some(i) = single {
 361         vec![i]
 362     } else {
 363         tcx.mir_keys(LOCAL_CRATE).iter().cloned().collect()
 364     }
 365 }