src/librustc_driver/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 //! The various pretty print routines.
  12
  13 pub use self::UserIdentifiedItem::*;
  14 pub use self::PpSourceMode::*;
  15 pub use self::PpMode::*;
  16 use self::NodesMatchingUII::*;
  17
  18 use rustc_trans::back::link;
  19
  20 use driver;
  21
  22 use rustc::middle::ty;
  23 use rustc::middle::cfg;
  24 use rustc::middle::cfg::graphviz::LabelledCFG;
  25 use rustc::session::Session;
  26 use rustc::session::config::Input;
  27 use rustc::util::ppaux;
  28 use rustc_borrowck as borrowck;
  29 use rustc_borrowck::graphviz as borrowck_dot;
  30 use rustc_resolve as resolve;
  31
  32 use syntax::ast;
  33 use syntax::ast_map::{self, blocks, NodePrinter};
  34 use syntax::codemap;
  35 use syntax::fold::{self, Folder};
  36 use syntax::print::{pp, pprust};
  37 use syntax::ptr::P;
  38
  39 use graphviz as dot;
  40
  41 use std::old_io::{self, MemReader};
  42 use std::option;
  43 use std::str::FromStr;
  44
  45 #[derive(Copy, PartialEq, Debug)]
  46 pub enum PpSourceMode {
  47     PpmNormal,
  48     PpmEveryBodyLoops,
  49     PpmExpanded,
  50     PpmTyped,
  51     PpmIdentified,
  52     PpmExpandedIdentified,
  53     PpmExpandedHygiene,
  54 }
  55
  56
  57 #[derive(Copy, PartialEq, Debug)]
  58 pub enum PpFlowGraphMode {
  59     Default,
  60     /// Drops the labels from the edges in the flowgraph output. This
  61     /// is mostly for use in the --xpretty flowgraph run-make tests,
  62     /// since the labels are largely uninteresting in those cases and
  63     /// have become a pain to maintain.
  64     UnlabelledEdges,
  65 }
  66 #[derive(Copy, PartialEq, Debug)]
  67 pub enum PpMode {
  68     PpmSource(PpSourceMode),
  69     PpmFlowGraph(PpFlowGraphMode),
  70 }
  71
  72 pub fn parse_pretty(sess: &Session,
  73                     name: &str,
  74                     extended: bool) -> (PpMode, Option<UserIdentifiedItem>) {
  75     let mut split = name.splitn(1, '=');
  76     let first = split.next().unwrap();
  77     let opt_second = split.next();
  78     let first = match (first, extended) {
  79         ("normal", _)       => PpmSource(PpmNormal),
  80         ("everybody_loops", true) => PpmSource(PpmEveryBodyLoops),
  81         ("expanded", _)     => PpmSource(PpmExpanded),
  82         ("typed", _)        => PpmSource(PpmTyped),
  83         ("expanded,identified", _) => PpmSource(PpmExpandedIdentified),
  84         ("expanded,hygiene", _) => PpmSource(PpmExpandedHygiene),
  85         ("identified", _)   => PpmSource(PpmIdentified),
  86         ("flowgraph", true)    => PpmFlowGraph(PpFlowGraphMode::Default),
  87         ("flowgraph,unlabelled", true)    => PpmFlowGraph(PpFlowGraphMode::UnlabelledEdges),
  88         _ => {
  89             if extended {
  90                 sess.fatal(&format!(
  91                     "argument to `xpretty` must be one of `normal`, \
  92                      `expanded`, `flowgraph[,unlabelled]=<nodeid>`, `typed`, `identified`, \
  93                      `expanded,identified`, or `everybody_loops`; got {}", name));
  94             } else {
  95                 sess.fatal(&format!(
  96                     "argument to `pretty` must be one of `normal`, \
  97                      `expanded`, `typed`, `identified`, \
  98                      or `expanded,identified`; got {}", name));
  99             }
 100         }
 101     };
 102     let opt_second = opt_second.and_then(|s| s.parse::<UserIdentifiedItem>().ok());
 103     (first, opt_second)
 104 }
 105
 106
 107
 108 // This slightly awkward construction is to allow for each PpMode to
 109 // choose whether it needs to do analyses (which can consume the
 110 // Session) and then pass through the session (now attached to the
 111 // analysis results) on to the chosen pretty-printer, along with the
 112 // `&PpAnn` object.
 113 //
 114 // Note that since the `&PrinterSupport` is freshly constructed on each
 115 // call, it would not make sense to try to attach the lifetime of `self`
 116 // to the lifetime of the `&PrinterObject`.
 117 //
 118 // (The `use_once_payload` is working around the current lack of once
 119 // functions in the compiler.)
 120
 121 impl PpSourceMode {
 122     /// Constructs a `PrinterSupport` object and passes it to `f`.
 123     fn call_with_pp_support<'tcx, A, B, F>(&self,
 124                                            sess: Session,
 125                                            ast_map: Option<ast_map::Map<'tcx>>,
 126                                            arenas: &'tcx ty::CtxtArenas<'tcx>,
 127                                            id: String,
 128                                            payload: B,
 129                                            f: F) -> A where
 130         F: FnOnce(&PrinterSupport, B) -> A,
 131     {
 132         match *self {
 133             PpmNormal | PpmEveryBodyLoops | PpmExpanded => {
 134                 let annotation = NoAnn { sess: sess, ast_map: ast_map };
 135                 f(&annotation, payload)
 136             }
 137
 138             PpmIdentified | PpmExpandedIdentified => {
 139                 let annotation = IdentifiedAnnotation { sess: sess, ast_map: ast_map };
 140                 f(&annotation, payload)
 141             }
 142             PpmExpandedHygiene => {
 143                 let annotation = HygieneAnnotation { sess: sess, ast_map: ast_map };
 144                 f(&annotation, payload)
 145             }
 146             PpmTyped => {
 147                 let ast_map = ast_map.expect("--pretty=typed missing ast_map");
 148                 let analysis = driver::phase_3_run_analysis_passes(sess,
 149                                                                    ast_map,
 150                                                                    arenas,
 151                                                                    id,
 152                                                                    resolve::MakeGlobMap::No);
 153                 let annotation = TypedAnnotation { analysis: analysis };
 154                 f(&annotation, payload)
 155             }
 156         }
 157     }
 158 }
 159
 160 trait PrinterSupport<'ast>: pprust::PpAnn {
 161     /// Provides a uniform interface for re-extracting a reference to a
 162     /// `Session` from a value that now owns it.
 163     fn sess<'a>(&'a self) -> &'a Session;
 164
 165     /// Provides a uniform interface for re-extracting a reference to an
 166     /// `ast_map::Map` from a value that now owns it.
 167     fn ast_map<'a>(&'a self) -> Option<&'a ast_map::Map<'ast>>;
 168
 169     /// Produces the pretty-print annotation object.
 170     ///
 171     /// (Rust does not yet support upcasting from a trait object to
 172     /// an object for one of its super-traits.)
 173     fn pp_ann<'a>(&'a self) -> &'a pprust::PpAnn;
 174 }
 175
 176 struct NoAnn<'ast> {
 177     sess: Session,
 178     ast_map: Option<ast_map::Map<'ast>>
 179 }
 180
 181 impl<'ast> PrinterSupport<'ast> for NoAnn<'ast> {
 182     fn sess<'a>(&'a self) -> &'a Session { &self.sess }
 183
 184     fn ast_map<'a>(&'a self) -> Option<&'a ast_map::Map<'ast>> {
 185         self.ast_map.as_ref()
 186     }
 187
 188     fn pp_ann<'a>(&'a self) -> &'a pprust::PpAnn { self }
 189 }
 190
 191 impl<'ast> pprust::PpAnn for NoAnn<'ast> {}
 192
 193 struct IdentifiedAnnotation<'ast> {
 194     sess: Session,
 195     ast_map: Option<ast_map::Map<'ast>>,
 196 }
 197
 198 impl<'ast> PrinterSupport<'ast> for IdentifiedAnnotation<'ast> {
 199     fn sess<'a>(&'a self) -> &'a Session { &self.sess }
 200
 201     fn ast_map<'a>(&'a self) -> Option<&'a ast_map::Map<'ast>> {
 202         self.ast_map.as_ref()
 203     }
 204
 205     fn pp_ann<'a>(&'a self) -> &'a pprust::PpAnn { self }
 206 }
 207
 208 impl<'ast> pprust::PpAnn for IdentifiedAnnotation<'ast> {
 209     fn pre(&self,
 210            s: &mut pprust::State,
 211            node: pprust::AnnNode) -> old_io::IoResult<()> {
 212         match node {
 213             pprust::NodeExpr(_) => s.popen(),
 214             _ => Ok(())
 215         }
 216     }
 217     fn post(&self,
 218             s: &mut pprust::State,
 219             node: pprust::AnnNode) -> old_io::IoResult<()> {
 220         match node {
 221             pprust::NodeIdent(_) | pprust::NodeName(_) => Ok(()),
 222
 223             pprust::NodeItem(item) => {
 224                 try!(pp::space(&mut s.s));
 225                 s.synth_comment(item.id.to_string())
 226             }
 227             pprust::NodeBlock(blk) => {
 228                 try!(pp::space(&mut s.s));
 229                 s.synth_comment(format!("block {}", blk.id))
 230             }
 231             pprust::NodeExpr(expr) => {
 232                 try!(pp::space(&mut s.s));
 233                 try!(s.synth_comment(expr.id.to_string()));
 234                 s.pclose()
 235             }
 236             pprust::NodePat(pat) => {
 237                 try!(pp::space(&mut s.s));
 238                 s.synth_comment(format!("pat {}", pat.id))
 239             }
 240         }
 241     }
 242 }
 243
 244 struct HygieneAnnotation<'ast> {
 245     sess: Session,
 246     ast_map: Option<ast_map::Map<'ast>>,
 247 }
 248
 249 impl<'ast> PrinterSupport<'ast> for HygieneAnnotation<'ast> {
 250     fn sess<'a>(&'a self) -> &'a Session { &self.sess }
 251
 252     fn ast_map<'a>(&'a self) -> Option<&'a ast_map::Map<'ast>> {
 253         self.ast_map.as_ref()
 254     }
 255
 256     fn pp_ann<'a>(&'a self) -> &'a pprust::PpAnn { self }
 257 }
 258
 259 impl<'ast> pprust::PpAnn for HygieneAnnotation<'ast> {
 260     fn post(&self,
 261             s: &mut pprust::State,
 262             node: pprust::AnnNode) -> old_io::IoResult<()> {
 263         match node {
 264             pprust::NodeIdent(&ast::Ident { name: ast::Name(nm), ctxt }) => {
 265                 try!(pp::space(&mut s.s));
 266                 // FIXME #16420: this doesn't display the connections
 267                 // between syntax contexts
 268                 s.synth_comment(format!("{}#{}", nm, ctxt))
 269             }
 270             pprust::NodeName(&ast::Name(nm)) => {
 271                 try!(pp::space(&mut s.s));
 272                 s.synth_comment(nm.to_string())
 273             }
 274             _ => Ok(())
 275         }
 276     }
 277 }
 278
 279
 280 struct TypedAnnotation<'tcx> {
 281     analysis: ty::CrateAnalysis<'tcx>,
 282 }
 283
 284 impl<'tcx> PrinterSupport<'tcx> for TypedAnnotation<'tcx> {
 285     fn sess<'a>(&'a self) -> &'a Session { &self.analysis.ty_cx.sess }
 286
 287     fn ast_map<'a>(&'a self) -> Option<&'a ast_map::Map<'tcx>> {
 288         Some(&self.analysis.ty_cx.map)
 289     }
 290
 291     fn pp_ann<'a>(&'a self) -> &'a pprust::PpAnn { self }
 292 }
 293
 294 impl<'tcx> pprust::PpAnn for TypedAnnotation<'tcx> {
 295     fn pre(&self,
 296            s: &mut pprust::State,
 297            node: pprust::AnnNode) -> old_io::IoResult<()> {
 298         match node {
 299             pprust::NodeExpr(_) => s.popen(),
 300             _ => Ok(())
 301         }
 302     }
 303     fn post(&self,
 304             s: &mut pprust::State,
 305             node: pprust::AnnNode) -> old_io::IoResult<()> {
 306         let tcx = &self.analysis.ty_cx;
 307         match node {
 308             pprust::NodeExpr(expr) => {
 309                 try!(pp::space(&mut s.s));
 310                 try!(pp::word(&mut s.s, "as"));
 311                 try!(pp::space(&mut s.s));
 312                 try!(pp::word(&mut s.s,
 313                               &ppaux::ty_to_string(
 314                                   tcx,
 315                                   ty::expr_ty(tcx, expr))[]));
 316                 s.pclose()
 317             }
 318             _ => Ok(())
 319         }
 320     }
 321 }
 322
 323 fn gather_flowgraph_variants(sess: &Session) -> Vec<borrowck_dot::Variant> {
 324     let print_loans = sess.opts.debugging_opts.flowgraph_print_loans;
 325     let print_moves = sess.opts.debugging_opts.flowgraph_print_moves;
 326     let print_assigns = sess.opts.debugging_opts.flowgraph_print_assigns;
 327     let print_all = sess.opts.debugging_opts.flowgraph_print_all;
 328     let mut variants = Vec::new();
 329     if print_all || print_loans {
 330         variants.push(borrowck_dot::Loans);
 331     }
 332     if print_all || print_moves {
 333         variants.push(borrowck_dot::Moves);
 334     }
 335     if print_all || print_assigns {
 336         variants.push(borrowck_dot::Assigns);
 337     }
 338     variants
 339 }
 340
 341 #[derive(Clone, Debug)]
 342 pub enum UserIdentifiedItem {
 343     ItemViaNode(ast::NodeId),
 344     ItemViaPath(Vec<String>),
 345 }
 346
 347 impl FromStr for UserIdentifiedItem {
 348     type Err = ();
 349     fn from_str(s: &str) -> Result<UserIdentifiedItem, ()> {
 350         Ok(s.parse().map(ItemViaNode).unwrap_or_else(|_| {
 351             ItemViaPath(s.split_str("::").map(|s| s.to_string()).collect())
 352         }))
 353     }
 354 }
 355
 356 enum NodesMatchingUII<'a, 'ast: 'a> {
 357     NodesMatchingDirect(option::IntoIter<ast::NodeId>),
 358     NodesMatchingSuffix(ast_map::NodesMatchingSuffix<'a, 'ast>),
 359 }
 360
 361 impl<'a, 'ast> Iterator for NodesMatchingUII<'a, 'ast> {
 362     type Item = ast::NodeId;
 363
 364     fn next(&mut self) -> Option<ast::NodeId> {
 365         match self {
 366             &mut NodesMatchingDirect(ref mut iter) => iter.next(),
 367             &mut NodesMatchingSuffix(ref mut iter) => iter.next(),
 368         }
 369     }
 370 }
 371
 372 impl UserIdentifiedItem {
 373     fn reconstructed_input(&self) -> String {
 374         match *self {
 375             ItemViaNode(node_id) => node_id.to_string(),
 376             ItemViaPath(ref parts) => parts.connect("::"),
 377         }
 378     }
 379
 380     fn all_matching_node_ids<'a, 'ast>(&'a self, map: &'a ast_map::Map<'ast>)
 381                                        -> NodesMatchingUII<'a, 'ast> {
 382         match *self {
 383             ItemViaNode(node_id) =>
 384                 NodesMatchingDirect(Some(node_id).into_iter()),
 385             ItemViaPath(ref parts) =>
 386                 NodesMatchingSuffix(map.nodes_matching_suffix(&parts[])),
 387         }
 388     }
 389
 390     fn to_one_node_id(self, user_option: &str, sess: &Session, map: &ast_map::Map) -> ast::NodeId {
 391         let fail_because = |is_wrong_because| -> ast::NodeId {
 392             let message =
 393                 format!("{} needs NodeId (int) or unique \
 394                          path suffix (b::c::d); got {}, which {}",
 395                         user_option,
 396                         self.reconstructed_input(),
 397                         is_wrong_because);
 398             sess.fatal(&message[])
 399         };
 400
 401         let mut saw_node = ast::DUMMY_NODE_ID;
 402         let mut seen = 0;
 403         for node in self.all_matching_node_ids(map) {
 404             saw_node = node;
 405             seen += 1;
 406             if seen > 1 {
 407                 fail_because("does not resolve uniquely");
 408             }
 409         }
 410         if seen == 0 {
 411             fail_because("does not resolve to any item");
 412         }
 413
 414         assert!(seen == 1);
 415         return saw_node;
 416     }
 417 }
 418
 419 fn needs_ast_map(ppm: &PpMode, opt_uii: &Option<UserIdentifiedItem>) -> bool {
 420     match *ppm {
 421         PpmSource(PpmNormal) |
 422         PpmSource(PpmEveryBodyLoops) |
 423         PpmSource(PpmIdentified) => opt_uii.is_some(),
 424
 425         PpmSource(PpmExpanded) |
 426         PpmSource(PpmExpandedIdentified) |
 427         PpmSource(PpmExpandedHygiene) |
 428         PpmSource(PpmTyped) |
 429         PpmFlowGraph(_) => true
 430     }
 431 }
 432
 433 fn needs_expansion(ppm: &PpMode) -> bool {
 434     match *ppm {
 435         PpmSource(PpmNormal) |
 436         PpmSource(PpmEveryBodyLoops) |
 437         PpmSource(PpmIdentified) => false,
 438
 439         PpmSource(PpmExpanded) |
 440         PpmSource(PpmExpandedIdentified) |
 441         PpmSource(PpmExpandedHygiene) |
 442         PpmSource(PpmTyped) |
 443         PpmFlowGraph(_) => true
 444     }
 445 }
 446
 447 struct ReplaceBodyWithLoop {
 448     within_static_or_const: bool,
 449 }
 450
 451 impl ReplaceBodyWithLoop {
 452     fn new() -> ReplaceBodyWithLoop {
 453         ReplaceBodyWithLoop { within_static_or_const: false }
 454     }
 455 }
 456
 457 impl fold::Folder for ReplaceBodyWithLoop {
 458     fn fold_item_underscore(&mut self, i: ast::Item_) -> ast::Item_ {
 459         match i {
 460             ast::ItemStatic(..) | ast::ItemConst(..) => {
 461                 self.within_static_or_const = true;
 462                 let ret = fold::noop_fold_item_underscore(i, self);
 463                 self.within_static_or_const = false;
 464                 return ret;
 465             }
 466             _ => {
 467                 fold::noop_fold_item_underscore(i, self)
 468             }
 469         }
 470     }
 471
 472
 473     fn fold_block(&mut self, b: P<ast::Block>) -> P<ast::Block> {
 474         fn expr_to_block(rules: ast::BlockCheckMode,
 475                          e: Option<P<ast::Expr>>) -> P<ast::Block> {
 476             P(ast::Block {
 477                 expr: e,
 478                 stmts: vec![], rules: rules,
 479                 id: ast::DUMMY_NODE_ID, span: codemap::DUMMY_SP,
 480             })
 481         }
 482
 483         if !self.within_static_or_const {
 484
 485             let empty_block = expr_to_block(ast::DefaultBlock, None);
 486             let loop_expr = P(ast::Expr {
 487                 node: ast::ExprLoop(empty_block, None),
 488                 id: ast::DUMMY_NODE_ID, span: codemap::DUMMY_SP
 489             });
 490
 491             expr_to_block(b.rules, Some(loop_expr))
 492
 493         } else {
 494             fold::noop_fold_block(b, self)
 495         }
 496     }
 497
 498     // in general the pretty printer processes unexpanded code, so
 499     // we override the default `fold_mac` method which panics.
 500     fn fold_mac(&mut self, mac: ast::Mac) -> ast::Mac {
 501         fold::noop_fold_mac(mac, self)
 502     }
 503 }
 504
 505 pub fn pretty_print_input(sess: Session,
 506                           cfg: ast::CrateConfig,
 507                           input: &Input,
 508                           ppm: PpMode,
 509                           opt_uii: Option<UserIdentifiedItem>,
 510                           ofile: Option<Path>) {
 511     let krate = driver::phase_1_parse_input(&sess, cfg, input);
 512
 513     let krate = if let PpmSource(PpmEveryBodyLoops) = ppm {
 514         let mut fold = ReplaceBodyWithLoop::new();
 515         fold.fold_crate(krate)
 516     } else {
 517         krate
 518     };
 519
 520     let id = link::find_crate_name(Some(&sess), &krate.attrs, input);
 521
 522     let is_expanded = needs_expansion(&ppm);
 523     let compute_ast_map = needs_ast_map(&ppm, &opt_uii);
 524     let krate = if compute_ast_map {
 525         match driver::phase_2_configure_and_expand(&sess, krate, &id[], None) {
 526             None => return,
 527             Some(k) => k
 528         }
 529     } else {
 530         krate
 531     };
 532
 533     let mut forest = ast_map::Forest::new(krate);
 534     let arenas = ty::CtxtArenas::new();
 535
 536     let (krate, ast_map) = if compute_ast_map {
 537         let map = driver::assign_node_ids_and_map(&sess, &mut forest);
 538         (map.krate(), Some(map))
 539     } else {
 540         (forest.krate(), None)
 541     };
 542
 543     let src_name = driver::source_name(input);
 544     let src = sess.codemap().get_filemap(&src_name[])
 545                             .src.as_bytes().to_vec();
 546     let mut rdr = MemReader::new(src);
 547
 548     let out = match ofile {
 549         None => box old_io::stdout() as Box<Writer+'static>,
 550         Some(p) => {
 551             let r = old_io::File::create(&p);
 552             match r {
 553                 Ok(w) => box w as Box<Writer+'static>,
 554                 Err(e) => panic!("print-print failed to open {} due to {}",
 555                                 p.display(), e),
 556             }
 557         }
 558     };
 559
 560     match (ppm, opt_uii) {
 561         (PpmSource(s), None) =>
 562             s.call_with_pp_support(
 563                 sess, ast_map, &arenas, id, out, |annotation, out| {
 564                     debug!("pretty printing source code {:?}", s);
 565                     let sess = annotation.sess();
 566                     pprust::print_crate(sess.codemap(),
 567                                         sess.diagnostic(),
 568                                         krate,
 569                                         src_name.to_string(),
 570                                         &mut rdr,
 571                                         out,
 572                                         annotation.pp_ann(),
 573                                         is_expanded)
 574                 }),
 575
 576         (PpmSource(s), Some(uii)) =>
 577             s.call_with_pp_support(
 578                 sess, ast_map, &arenas, id, (out,uii), |annotation, (out,uii)| {
 579                     debug!("pretty printing source code {:?}", s);
 580                     let sess = annotation.sess();
 581                     let ast_map = annotation.ast_map()
 582                         .expect("--pretty missing ast_map");
 583                     let mut pp_state =
 584                         pprust::State::new_from_input(sess.codemap(),
 585                                                       sess.diagnostic(),
 586                                                       src_name.to_string(),
 587                                                       &mut rdr,
 588                                                       out,
 589                                                       annotation.pp_ann(),
 590                                                       is_expanded);
 591                     for node_id in uii.all_matching_node_ids(ast_map) {
 592                         let node = ast_map.get(node_id);
 593                         try!(pp_state.print_node(&node));
 594                         try!(pp::space(&mut pp_state.s));
 595                         try!(pp_state.synth_comment(ast_map.path_to_string(node_id)));
 596                         try!(pp::hardbreak(&mut pp_state.s));
 597                     }
 598                     pp::eof(&mut pp_state.s)
 599                 }),
 600
 601         (PpmFlowGraph(mode), opt_uii) => {
 602             debug!("pretty printing flow graph for {:?}", opt_uii);
 603             let uii = opt_uii.unwrap_or_else(|| {
 604                 sess.fatal(&format!("`pretty flowgraph=..` needs NodeId (int) or
 605                                      unique path suffix (b::c::d)")[])
 606
 607             });
 608             let ast_map = ast_map.expect("--pretty flowgraph missing ast_map");
 609             let nodeid = uii.to_one_node_id("--pretty", &sess, &ast_map);
 610
 611             let node = ast_map.find(nodeid).unwrap_or_else(|| {
 612                 sess.fatal(&format!("--pretty flowgraph couldn't find id: {}",
 613                                    nodeid)[])
 614             });
 615
 616             let code = blocks::Code::from_node(node);
 617             match code {
 618                 Some(code) => {
 619                     let variants = gather_flowgraph_variants(&sess);
 620                     let analysis = driver::phase_3_run_analysis_passes(sess,
 621                                                                        ast_map,
 622                                                                        &arenas,
 623                                                                        id,
 624                                                                        resolve::MakeGlobMap::No);
 625                     print_flowgraph(variants, analysis, code, mode, out)
 626                 }
 627                 None => {
 628                     let message = format!("--pretty=flowgraph needs \
 629                                            block, fn, or method; got {:?}",
 630                                           node);
 631
 632                     // point to what was found, if there's an
 633                     // accessible span.
 634                     match ast_map.opt_span(nodeid) {
 635                         Some(sp) => sess.span_fatal(sp, &message[]),
 636                         None => sess.fatal(&message[])
 637                     }
 638                 }
 639             }
 640         }
 641     }.unwrap()
 642 }
 643
 644 fn print_flowgraph<W:old_io::Writer>(variants: Vec<borrowck_dot::Variant>,
 645                                  analysis: ty::CrateAnalysis,
 646                                  code: blocks::Code,
 647                                  mode: PpFlowGraphMode,
 648                                  mut out: W) -> old_io::IoResult<()> {
 649     let ty_cx = &analysis.ty_cx;
 650     let cfg = match code {
 651         blocks::BlockCode(block) => cfg::CFG::new(ty_cx, &*block),
 652         blocks::FnLikeCode(fn_like) => cfg::CFG::new(ty_cx, &*fn_like.body()),
 653     };
 654     let labelled_edges = mode != PpFlowGraphMode::UnlabelledEdges;
 655     let lcfg = LabelledCFG {
 656         ast_map: &ty_cx.map,
 657         cfg: &cfg,
 658         name: format!("node_{}", code.id()),
 659         labelled_edges: labelled_edges,
 660     };
 661
 662     match code {
 663         _ if variants.len() == 0 => {
 664             let r = dot::render(&lcfg, &mut out);
 665             return expand_err_details(r);
 666         }
 667         blocks::BlockCode(_) => {
 668             ty_cx.sess.err("--pretty flowgraph with -Z flowgraph-print \
 669                             annotations requires fn-like node id.");
 670             return Ok(())
 671         }
 672         blocks::FnLikeCode(fn_like) => {
 673             let fn_parts = borrowck::FnPartsWithCFG::from_fn_like(&fn_like, &cfg);
 674             let (bccx, analysis_data) =
 675                 borrowck::build_borrowck_dataflow_data_for_fn(ty_cx, fn_parts);
 676
 677             let lcfg = borrowck_dot::DataflowLabeller {
 678                 inner: lcfg,
 679                 variants: variants,
 680                 borrowck_ctxt: &bccx,
 681                 analysis_data: &analysis_data,
 682             };
 683             let r = dot::render(&lcfg, &mut out);
 684             return expand_err_details(r);
 685         }
 686     }
 687
 688     fn expand_err_details(r: old_io::IoResult<()>) -> old_io::IoResult<()> {
 689         r.map_err(|ioerr| {
 690             let orig_detail = ioerr.detail.clone();
 691             let m = "graphviz::render failed";
 692             old_io::IoError {
 693                 detail: Some(match orig_detail {
 694                     None => m.to_string(),
 695                     Some(d) => format!("{}: {}", m, d)
 696                 }),
 697                 ..ioerr
 698             }
 699         })
 700     }
 701 }