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::io::{self, MemReader};
  42 use std::option;
  43 use std::str::FromStr;
  44
  45 #[derive(Copy, PartialEq, Show)]
  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, Show)]
  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, Show)]
  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).as_slice());
  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).as_slice());
  99             }
 100         }
 101     };
 102     let opt_second = opt_second.and_then(|s| s.parse::<UserIdentifiedItem>());
 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) -> 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) -> 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) -> 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) -> 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) -> 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, Show)]
 342 pub enum UserIdentifiedItem {
 343     ItemViaNode(ast::NodeId),
 344     ItemViaPath(Vec<String>),
 345 }
 346
 347 impl FromStr for UserIdentifiedItem {
 348     fn from_str(s: &str) -> Option<UserIdentifiedItem> {
 349         s.parse().map(ItemViaNode).or_else(|| {
 350             let v : Vec<_> = s.split_str("::")
 351                 .map(|x|x.to_string())
 352                 .collect();
 353             Some(ItemViaPath(v))
 354         })
 355     }
 356 }
 357
 358 enum NodesMatchingUII<'a, 'ast: 'a> {
 359     NodesMatchingDirect(option::IntoIter<ast::NodeId>),
 360     NodesMatchingSuffix(ast_map::NodesMatchingSuffix<'a, 'ast>),
 361 }
 362
 363 impl<'a, 'ast> Iterator for NodesMatchingUII<'a, 'ast> {
 364     type Item = ast::NodeId;
 365
 366     fn next(&mut self) -> Option<ast::NodeId> {
 367         match self {
 368             &mut NodesMatchingDirect(ref mut iter) => iter.next(),
 369             &mut NodesMatchingSuffix(ref mut iter) => iter.next(),
 370         }
 371     }
 372 }
 373
 374 impl UserIdentifiedItem {
 375     fn reconstructed_input(&self) -> String {
 376         match *self {
 377             ItemViaNode(node_id) => node_id.to_string(),
 378             ItemViaPath(ref parts) => parts.connect("::"),
 379         }
 380     }
 381
 382     fn all_matching_node_ids<'a, 'ast>(&'a self, map: &'a ast_map::Map<'ast>)
 383                                        -> NodesMatchingUII<'a, 'ast> {
 384         match *self {
 385             ItemViaNode(node_id) =>
 386                 NodesMatchingDirect(Some(node_id).into_iter()),
 387             ItemViaPath(ref parts) =>
 388                 NodesMatchingSuffix(map.nodes_matching_suffix(&parts[])),
 389         }
 390     }
 391
 392     fn to_one_node_id(self, user_option: &str, sess: &Session, map: &ast_map::Map) -> ast::NodeId {
 393         let fail_because = |&: is_wrong_because| -> ast::NodeId {
 394             let message =
 395                 format!("{} needs NodeId (int) or unique \
 396                          path suffix (b::c::d); got {}, which {}",
 397                         user_option,
 398                         self.reconstructed_input(),
 399                         is_wrong_because);
 400             sess.fatal(&message[])
 401         };
 402
 403         let mut saw_node = ast::DUMMY_NODE_ID;
 404         let mut seen = 0u;
 405         for node in self.all_matching_node_ids(map) {
 406             saw_node = node;
 407             seen += 1;
 408             if seen > 1 {
 409                 fail_because("does not resolve uniquely");
 410             }
 411         }
 412         if seen == 0 {
 413             fail_because("does not resolve to any item");
 414         }
 415
 416         assert!(seen == 1);
 417         return saw_node;
 418     }
 419 }
 420
 421 fn needs_ast_map(ppm: &PpMode, opt_uii: &Option<UserIdentifiedItem>) -> bool {
 422     match *ppm {
 423         PpmSource(PpmNormal) |
 424         PpmSource(PpmEveryBodyLoops) |
 425         PpmSource(PpmIdentified) => opt_uii.is_some(),
 426
 427         PpmSource(PpmExpanded) |
 428         PpmSource(PpmExpandedIdentified) |
 429         PpmSource(PpmExpandedHygiene) |
 430         PpmSource(PpmTyped) |
 431         PpmFlowGraph(_) => true
 432     }
 433 }
 434
 435 fn needs_expansion(ppm: &PpMode) -> bool {
 436     match *ppm {
 437         PpmSource(PpmNormal) |
 438         PpmSource(PpmEveryBodyLoops) |
 439         PpmSource(PpmIdentified) => false,
 440
 441         PpmSource(PpmExpanded) |
 442         PpmSource(PpmExpandedIdentified) |
 443         PpmSource(PpmExpandedHygiene) |
 444         PpmSource(PpmTyped) |
 445         PpmFlowGraph(_) => true
 446     }
 447 }
 448
 449 struct ReplaceBodyWithLoop {
 450     within_static_or_const: bool,
 451 }
 452
 453 impl ReplaceBodyWithLoop {
 454     fn new() -> ReplaceBodyWithLoop {
 455         ReplaceBodyWithLoop { within_static_or_const: false }
 456     }
 457 }
 458
 459 impl fold::Folder for ReplaceBodyWithLoop {
 460     fn fold_item_underscore(&mut self, i: ast::Item_) -> ast::Item_ {
 461         match i {
 462             ast::ItemStatic(..) | ast::ItemConst(..) => {
 463                 self.within_static_or_const = true;
 464                 let ret = fold::noop_fold_item_underscore(i, self);
 465                 self.within_static_or_const = false;
 466                 return ret;
 467             }
 468             _ => {
 469                 fold::noop_fold_item_underscore(i, self)
 470             }
 471         }
 472     }
 473
 474
 475     fn fold_block(&mut self, b: P<ast::Block>) -> P<ast::Block> {
 476         fn expr_to_block(rules: ast::BlockCheckMode,
 477                          e: Option<P<ast::Expr>>) -> P<ast::Block> {
 478             P(ast::Block {
 479                 expr: e,
 480                 view_items: vec![], stmts: vec![], rules: rules,
 481                 id: ast::DUMMY_NODE_ID, span: codemap::DUMMY_SP,
 482             })
 483         }
 484
 485         if !self.within_static_or_const {
 486
 487             let empty_block = expr_to_block(ast::DefaultBlock, None);
 488             let loop_expr = P(ast::Expr {
 489                 node: ast::ExprLoop(empty_block, None),
 490                 id: ast::DUMMY_NODE_ID, span: codemap::DUMMY_SP
 491             });
 492
 493             expr_to_block(b.rules, Some(loop_expr))
 494
 495         } else {
 496             fold::noop_fold_block(b, self)
 497         }
 498     }
 499
 500     // in general the pretty printer processes unexpanded code, so
 501     // we override the default `fold_mac` method which panics.
 502     fn fold_mac(&mut self, mac: ast::Mac) -> ast::Mac {
 503         fold::noop_fold_mac(mac, self)
 504     }
 505 }
 506
 507 pub fn pretty_print_input(sess: Session,
 508                           cfg: ast::CrateConfig,
 509                           input: &Input,
 510                           ppm: PpMode,
 511                           opt_uii: Option<UserIdentifiedItem>,
 512                           ofile: Option<Path>) {
 513     let krate = driver::phase_1_parse_input(&sess, cfg, input);
 514
 515     let krate = if let PpmSource(PpmEveryBodyLoops) = ppm {
 516         let mut fold = ReplaceBodyWithLoop::new();
 517         fold.fold_crate(krate)
 518     } else {
 519         krate
 520     };
 521
 522     let id = link::find_crate_name(Some(&sess), krate.attrs.as_slice(), input);
 523
 524     let is_expanded = needs_expansion(&ppm);
 525     let compute_ast_map = needs_ast_map(&ppm, &opt_uii);
 526     let krate = if compute_ast_map {
 527         match driver::phase_2_configure_and_expand(&sess, krate, &id[], None) {
 528             None => return,
 529             Some(k) => k
 530         }
 531     } else {
 532         krate
 533     };
 534
 535     let mut forest = ast_map::Forest::new(krate);
 536     let arenas = ty::CtxtArenas::new();
 537
 538     let (krate, ast_map) = if compute_ast_map {
 539         let map = driver::assign_node_ids_and_map(&sess, &mut forest);
 540         (map.krate(), Some(map))
 541     } else {
 542         (forest.krate(), None)
 543     };
 544
 545     let src_name = driver::source_name(input);
 546     let src = sess.codemap().get_filemap(&src_name[])
 547                             .src.as_bytes().to_vec();
 548     let mut rdr = MemReader::new(src);
 549
 550     let out = match ofile {
 551         None => box io::stdout() as Box<Writer+'static>,
 552         Some(p) => {
 553             let r = io::File::create(&p);
 554             match r {
 555                 Ok(w) => box w as Box<Writer+'static>,
 556                 Err(e) => panic!("print-print failed to open {} due to {}",
 557                                 p.display(), e),
 558             }
 559         }
 560     };
 561
 562     match (ppm, opt_uii) {
 563         (PpmSource(s), None) =>
 564             s.call_with_pp_support(
 565                 sess, ast_map, &arenas, id, out, |annotation, out| {
 566                     debug!("pretty printing source code {:?}", s);
 567                     let sess = annotation.sess();
 568                     pprust::print_crate(sess.codemap(),
 569                                         sess.diagnostic(),
 570                                         krate,
 571                                         src_name.to_string(),
 572                                         &mut rdr,
 573                                         out,
 574                                         annotation.pp_ann(),
 575                                         is_expanded)
 576                 }),
 577
 578         (PpmSource(s), Some(uii)) =>
 579             s.call_with_pp_support(
 580                 sess, ast_map, &arenas, id, (out,uii), |annotation, (out,uii)| {
 581                     debug!("pretty printing source code {:?}", s);
 582                     let sess = annotation.sess();
 583                     let ast_map = annotation.ast_map()
 584                         .expect("--pretty missing ast_map");
 585                     let mut pp_state =
 586                         pprust::State::new_from_input(sess.codemap(),
 587                                                       sess.diagnostic(),
 588                                                       src_name.to_string(),
 589                                                       &mut rdr,
 590                                                       out,
 591                                                       annotation.pp_ann(),
 592                                                       is_expanded);
 593                     for node_id in uii.all_matching_node_ids(ast_map) {
 594                         let node = ast_map.get(node_id);
 595                         try!(pp_state.print_node(&node));
 596                         try!(pp::space(&mut pp_state.s));
 597                         try!(pp_state.synth_comment(ast_map.path_to_string(node_id)));
 598                         try!(pp::hardbreak(&mut pp_state.s));
 599                     }
 600                     pp::eof(&mut pp_state.s)
 601                 }),
 602
 603         (PpmFlowGraph(mode), opt_uii) => {
 604             debug!("pretty printing flow graph for {:?}", opt_uii);
 605             let uii = opt_uii.unwrap_or_else(|| {
 606                 sess.fatal(&format!("`pretty flowgraph=..` needs NodeId (int) or
 607                                      unique path suffix (b::c::d)")[])
 608
 609             });
 610             let ast_map = ast_map.expect("--pretty flowgraph missing ast_map");
 611             let nodeid = uii.to_one_node_id("--pretty", &sess, &ast_map);
 612
 613             let node = ast_map.find(nodeid).unwrap_or_else(|| {
 614                 sess.fatal(&format!("--pretty flowgraph couldn't find id: {}",
 615                                    nodeid)[])
 616             });
 617
 618             let code = blocks::Code::from_node(node);
 619             match code {
 620                 Some(code) => {
 621                     let variants = gather_flowgraph_variants(&sess);
 622                     let analysis = driver::phase_3_run_analysis_passes(sess,
 623                                                                        ast_map,
 624                                                                        &arenas,
 625                                                                        id,
 626                                                                        resolve::MakeGlobMap::No);
 627                     print_flowgraph(variants, analysis, code, mode, out)
 628                 }
 629                 None => {
 630                     let message = format!("--pretty=flowgraph needs \
 631                                            block, fn, or method; got {:?}",
 632                                           node);
 633
 634                     // point to what was found, if there's an
 635                     // accessible span.
 636                     match ast_map.opt_span(nodeid) {
 637                         Some(sp) => sess.span_fatal(sp, &message[]),
 638                         None => sess.fatal(&message[])
 639                     }
 640                 }
 641             }
 642         }
 643     }.unwrap()
 644 }
 645
 646 fn print_flowgraph<W:io::Writer>(variants: Vec<borrowck_dot::Variant>,
 647                                  analysis: ty::CrateAnalysis,
 648                                  code: blocks::Code,
 649                                  mode: PpFlowGraphMode,
 650                                  mut out: W) -> io::IoResult<()> {
 651     let ty_cx = &analysis.ty_cx;
 652     let cfg = match code {
 653         blocks::BlockCode(block) => cfg::CFG::new(ty_cx, &*block),
 654         blocks::FnLikeCode(fn_like) => cfg::CFG::new(ty_cx, &*fn_like.body()),
 655     };
 656     let labelled_edges = mode != PpFlowGraphMode::UnlabelledEdges;
 657     let lcfg = LabelledCFG {
 658         ast_map: &ty_cx.map,
 659         cfg: &cfg,
 660         name: format!("node_{}", code.id()),
 661         labelled_edges: labelled_edges,
 662     };
 663
 664     match code {
 665         _ if variants.len() == 0 => {
 666             let r = dot::render(&lcfg, &mut out);
 667             return expand_err_details(r);
 668         }
 669         blocks::BlockCode(_) => {
 670             ty_cx.sess.err("--pretty flowgraph with -Z flowgraph-print \
 671                             annotations requires fn-like node id.");
 672             return Ok(())
 673         }
 674         blocks::FnLikeCode(fn_like) => {
 675             let fn_parts = borrowck::FnPartsWithCFG::from_fn_like(&fn_like, &cfg);
 676             let (bccx, analysis_data) =
 677                 borrowck::build_borrowck_dataflow_data_for_fn(ty_cx, fn_parts);
 678
 679             let lcfg = borrowck_dot::DataflowLabeller {
 680                 inner: lcfg,
 681                 variants: variants,
 682                 borrowck_ctxt: &bccx,
 683                 analysis_data: &analysis_data,
 684             };
 685             let r = dot::render(&lcfg, &mut out);
 686             return expand_err_details(r);
 687         }
 688     }
 689
 690     fn expand_err_details(r: io::IoResult<()>) -> io::IoResult<()> {
 691         r.map_err(|ioerr| {
 692             let orig_detail = ioerr.detail.clone();
 693             let m = "graphviz::render failed";
 694             io::IoError {
 695                 detail: Some(match orig_detail {
 696                     None => m.to_string(),
 697                     Some(d) => format!("{}: {}", m, d)
 698                 }),
 699                 ..ioerr
 700             }
 701         })
 702     }
 703 }