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 file_name = format!("rustc.node{}{}{}.{}.{}.mir",
 115                             source.item_id(), promotion_id, pass_num, pass_name, disambiguator);
 116     file_path.push(&file_name);
 117     let _ = fs::File::create(&file_path).and_then(|mut file| {
 118         writeln!(file, "// MIR for `{}`", node_path)?;
 119         writeln!(file, "// source = {:?}", source)?;
 120         writeln!(file, "// pass_name = {}", pass_name)?;
 121         writeln!(file, "// disambiguator = {}", disambiguator)?;
 122         writeln!(file, "")?;
 123         write_mir_fn(tcx, source, mir, &mut file)?;
 124         Ok(())
 125     });
 126 }
 127
 128 /// Write out a human-readable textual representation for the given MIR.
 129 pub fn write_mir_pretty<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 130                                   single: Option<DefId>,
 131                                   w: &mut Write)
 132                                   -> io::Result<()>
 133 {
 134     writeln!(w, "// WARNING: This output format is intended for human consumers only")?;
 135     writeln!(w, "// and is subject to change without notice. Knock yourself out.")?;
 136
 137     let mut first = true;
 138     for def_id in dump_mir_def_ids(tcx, single) {
 139         let mir = &tcx.optimized_mir(def_id);
 140
 141         if first {
 142             first = false;
 143         } else {
 144             // Put empty lines between all items
 145             writeln!(w, "")?;
 146         }
 147
 148         let id = tcx.hir.as_local_node_id(def_id).unwrap();
 149         let src = MirSource::from_node(tcx, id);
 150         write_mir_fn(tcx, src, mir, w)?;
 151
 152         for (i, mir) in mir.promoted.iter_enumerated() {
 153             writeln!(w, "")?;
 154             write_mir_fn(tcx, MirSource::Promoted(id, i), mir, w)?;
 155         }
 156     }
 157     Ok(())
 158 }
 159
 160 pub fn write_mir_fn<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 161                               src: MirSource,
 162                               mir: &Mir<'tcx>,
 163                               w: &mut Write)
 164                               -> io::Result<()> {
 165     write_mir_intro(tcx, src, mir, w)?;
 166     for block in mir.basic_blocks().indices() {
 167         write_basic_block(tcx, block, mir, w)?;
 168         if block.index() + 1 != mir.basic_blocks().len() {
 169             writeln!(w, "")?;
 170         }
 171     }
 172
 173     writeln!(w, "}}")?;
 174     Ok(())
 175 }
 176
 177 /// Write out a human-readable textual representation for the given basic block.
 178 fn write_basic_block(tcx: TyCtxt,
 179                      block: BasicBlock,
 180                      mir: &Mir,
 181                      w: &mut Write)
 182                      -> io::Result<()> {
 183     let data = &mir[block];
 184
 185     // Basic block label at the top.
 186     writeln!(w, "{}{:?}: {{", INDENT, block)?;
 187
 188     // List of statements in the middle.
 189     let mut current_location = Location { block: block, statement_index: 0 };
 190     for statement in &data.statements {
 191         let indented_mir = format!("{0}{0}{1:?};", INDENT, statement);
 192         writeln!(w, "{0:1$} // {2}",
 193                  indented_mir,
 194                  ALIGN,
 195                  comment(tcx, statement.source_info))?;
 196
 197         current_location.statement_index += 1;
 198     }
 199
 200     // Terminator at the bottom.
 201     let indented_terminator = format!("{0}{0}{1:?};", INDENT, data.terminator().kind);
 202     writeln!(w, "{0:1$} // {2}",
 203              indented_terminator,
 204              ALIGN,
 205              comment(tcx, data.terminator().source_info))?;
 206
 207     writeln!(w, "{}}}", INDENT)
 208 }
 209
 210 fn comment(tcx: TyCtxt, SourceInfo { span, scope }: SourceInfo) -> String {
 211     format!("scope {} at {}", scope.index(), tcx.sess.codemap().span_to_string(span))
 212 }
 213
 214 /// Prints user-defined variables in a scope tree.
 215 ///
 216 /// Returns the total number of variables printed.
 217 fn write_scope_tree(tcx: TyCtxt,
 218                     mir: &Mir,
 219                     scope_tree: &FxHashMap<VisibilityScope, Vec<VisibilityScope>>,
 220                     w: &mut Write,
 221                     parent: VisibilityScope,
 222                     depth: usize)
 223                     -> io::Result<()> {
 224     let indent = depth * INDENT.len();
 225
 226     let children = match scope_tree.get(&parent) {
 227         Some(childs) => childs,
 228         None => return Ok(()),
 229     };
 230
 231     for &child in children {
 232         let data = &mir.visibility_scopes[child];
 233         assert_eq!(data.parent_scope, Some(parent));
 234         writeln!(w, "{0:1$}scope {2} {{", "", indent, child.index())?;
 235
 236         // User variable types (including the user's name in a comment).
 237         for local in mir.vars_iter() {
 238             let var = &mir.local_decls[local];
 239             let (name, source_info) = if var.source_info.scope == child {
 240                 (var.name.unwrap(), var.source_info)
 241             } else {
 242                 // Not a variable or not declared in this scope.
 243                 continue;
 244             };
 245
 246             let mut_str = if var.mutability == Mutability::Mut {
 247                 "mut "
 248             } else {
 249                 ""
 250             };
 251
 252             let indent = indent + INDENT.len();
 253             let indented_var = format!("{0:1$}let {2}{3:?}: {4};",
 254                                        INDENT,
 255                                        indent,
 256                                        mut_str,
 257                                        local,
 258                                        var.ty);
 259             writeln!(w, "{0:1$} // \"{2}\" in {3}",
 260                      indented_var,
 261                      ALIGN,
 262                      name,
 263                      comment(tcx, source_info))?;
 264         }
 265
 266         write_scope_tree(tcx, mir, scope_tree, w, child, depth + 1)?;
 267
 268         writeln!(w, "{0:1$}}}", "", depth * INDENT.len())?;
 269     }
 270
 271     Ok(())
 272 }
 273
 274 /// Write out a human-readable textual representation of the MIR's `fn` type and the types of its
 275 /// local variables (both user-defined bindings and compiler temporaries).
 276 fn write_mir_intro<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 277                              src: MirSource,
 278                              mir: &Mir,
 279                              w: &mut Write)
 280                              -> io::Result<()> {
 281     write_mir_sig(tcx, src, mir, w)?;
 282     writeln!(w, " {{")?;
 283
 284     // construct a scope tree and write it out
 285     let mut scope_tree: FxHashMap<VisibilityScope, Vec<VisibilityScope>> = FxHashMap();
 286     for (index, scope_data) in mir.visibility_scopes.iter().enumerate() {
 287         if let Some(parent) = scope_data.parent_scope {
 288             scope_tree.entry(parent)
 289                       .or_insert(vec![])
 290                       .push(VisibilityScope::new(index));
 291         } else {
 292             // Only the argument scope has no parent, because it's the root.
 293             assert_eq!(index, ARGUMENT_VISIBILITY_SCOPE.index());
 294         }
 295     }
 296
 297     // Print return pointer
 298     let indented_retptr = format!("{}let mut {:?}: {};",
 299                                   INDENT,
 300                                   RETURN_POINTER,
 301                                   mir.return_ty);
 302     writeln!(w, "{0:1$} // return pointer",
 303              indented_retptr,
 304              ALIGN)?;
 305
 306     write_scope_tree(tcx, mir, &scope_tree, w, ARGUMENT_VISIBILITY_SCOPE, 1)?;
 307
 308     write_temp_decls(mir, w)?;
 309
 310     // Add an empty line before the first block is printed.
 311     writeln!(w, "")?;
 312
 313     Ok(())
 314 }
 315
 316 fn write_mir_sig(tcx: TyCtxt, src: MirSource, mir: &Mir, w: &mut Write)
 317                  -> io::Result<()>
 318 {
 319     match src {
 320         MirSource::Fn(_) => write!(w, "fn")?,
 321         MirSource::Const(_) => write!(w, "const")?,
 322         MirSource::Static(_, hir::MutImmutable) => write!(w, "static")?,
 323         MirSource::Static(_, hir::MutMutable) => write!(w, "static mut")?,
 324         MirSource::Promoted(_, i) => write!(w, "{:?} in", i)?
 325     }
 326
 327     item_path::with_forced_impl_filename_line(|| { // see notes on #41697 elsewhere
 328         write!(w, " {}", tcx.node_path_str(src.item_id()))
 329     })?;
 330
 331     if let MirSource::Fn(_) = src {
 332         write!(w, "(")?;
 333
 334         // fn argument types.
 335         for (i, arg) in mir.args_iter().enumerate() {
 336             if i != 0 {
 337                 write!(w, ", ")?;
 338             }
 339             write!(w, "{:?}: {}", Lvalue::Local(arg), mir.local_decls[arg].ty)?;
 340         }
 341
 342         write!(w, ") -> {}", mir.return_ty)
 343     } else {
 344         assert_eq!(mir.arg_count, 0);
 345         write!(w, ": {} =", mir.return_ty)
 346     }
 347 }
 348
 349 fn write_temp_decls(mir: &Mir, w: &mut Write) -> io::Result<()> {
 350     // Compiler-introduced temporary types.
 351     for temp in mir.temps_iter() {
 352         writeln!(w, "{}let mut {:?}: {};", INDENT, temp, mir.local_decls[temp].ty)?;
 353     }
 354
 355     Ok(())
 356 }
 357
 358 pub fn dump_mir_def_ids(tcx: TyCtxt, single: Option<DefId>) -> Vec<DefId> {
 359     if let Some(i) = single {
 360         vec![i]
 361     } else {
 362         tcx.mir_keys(LOCAL_CRATE).iter().cloned().collect()
 363     }
 364 }