src/librustc_metadata/tydecode.rs

   1 // Copyright 2012-2014 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
  12 // Type decoding
  13
  14 // tjc note: Would be great to have a `match check` macro equivalent
  15 // for some of these
  16
  17 #![allow(non_camel_case_types)]
  18
  19 use rustc_front::hir;
  20
  21 use middle::def_id::{DefId, DefIndex};
  22 use middle::region;
  23 use middle::subst;
  24 use middle::subst::VecPerParamSpace;
  25 use middle::ty::{self, ToPredicate, Ty, TypeFoldable};
  26
  27 use rbml;
  28 use rbml::leb128;
  29 use std::str;
  30 use syntax::abi;
  31 use syntax::ast;
  32 use syntax::parse::token;
  33
  34 // Compact string representation for Ty values. API TyStr &
  35 // parse_from_str. Extra parameters are for converting to/from def_ids in the
  36 // data buffer. Whatever format you choose should not contain pipe characters.
  37
  38 pub type DefIdConvert<'a> = &'a mut FnMut(DefId) -> DefId;
  39
  40 pub struct TyDecoder<'a, 'tcx: 'a> {
  41     data: &'a [u8],
  42     krate: ast::CrateNum,
  43     pos: usize,
  44     tcx: &'a ty::ctxt<'tcx>,
  45     conv_def_id: DefIdConvert<'a>,
  46 }
  47
  48 impl<'a,'tcx> TyDecoder<'a,'tcx> {
  49     pub fn with_doc(tcx: &'a ty::ctxt<'tcx>,
  50                     crate_num: ast::CrateNum,
  51                     doc: rbml::Doc<'a>,
  52                     conv: DefIdConvert<'a>)
  53                     -> TyDecoder<'a,'tcx> {
  54         TyDecoder::new(doc.data, crate_num, doc.start, tcx, conv)
  55     }
  56
  57     pub fn new(data: &'a [u8],
  58                crate_num: ast::CrateNum,
  59                pos: usize,
  60                tcx: &'a ty::ctxt<'tcx>,
  61                conv: DefIdConvert<'a>)
  62                -> TyDecoder<'a, 'tcx> {
  63         TyDecoder {
  64             data: data,
  65             krate: crate_num,
  66             pos: pos,
  67             tcx: tcx,
  68             conv_def_id: conv,
  69         }
  70     }
  71
  72     pub fn position(&self) -> usize {
  73         self.pos
  74     }
  75
  76     fn peek(&self) -> char {
  77         self.data[self.pos] as char
  78     }
  79
  80     fn next(&mut self) -> char {
  81         let ch = self.data[self.pos] as char;
  82         self.pos = self.pos + 1;
  83         return ch;
  84     }
  85
  86     fn next_byte(&mut self) -> u8 {
  87         let b = self.data[self.pos];
  88         self.pos = self.pos + 1;
  89         return b;
  90     }
  91
  92     fn scan<F>(&mut self, mut is_last: F) -> &'a [u8]
  93         where F: FnMut(char) -> bool,
  94     {
  95         let start_pos = self.pos;
  96         debug!("scan: '{}' (start)", self.data[self.pos] as char);
  97         while !is_last(self.data[self.pos] as char) {
  98             self.pos += 1;
  99             debug!("scan: '{}'", self.data[self.pos] as char);
 100         }
 101         let end_pos = self.pos;
 102         self.pos += 1;
 103         return &self.data[start_pos..end_pos];
 104     }
 105
 106     fn parse_vuint(&mut self) -> usize {
 107         let (value, bytes_read) = leb128::read_unsigned_leb128(self.data,
 108                                                                self.pos);
 109         self.pos += bytes_read;
 110         value as usize
 111     }
 112
 113     fn parse_name(&mut self, last: char) -> ast::Name {
 114         fn is_last(b: char, c: char) -> bool { return c == b; }
 115         let bytes = self.scan(|a| is_last(last, a));
 116         token::intern(str::from_utf8(bytes).unwrap())
 117     }
 118
 119     fn parse_size(&mut self) -> Option<usize> {
 120         assert_eq!(self.next(), '/');
 121
 122         if self.peek() == '|' {
 123             assert_eq!(self.next(), '|');
 124             None
 125         } else {
 126             let n = self.parse_uint();
 127             assert_eq!(self.next(), '|');
 128             Some(n)
 129         }
 130     }
 131
 132     fn parse_vec_per_param_space<T, F>(&mut self, mut f: F) -> VecPerParamSpace<T> where
 133         F: FnMut(&mut TyDecoder<'a, 'tcx>) -> T,
 134     {
 135         let mut r = VecPerParamSpace::empty();
 136         for &space in &subst::ParamSpace::all() {
 137             assert_eq!(self.next(), '[');
 138             while self.peek() != ']' {
 139                 r.push(space, f(self));
 140             }
 141             assert_eq!(self.next(), ']');
 142         }
 143         r
 144     }
 145
 146     pub fn parse_substs(&mut self) -> subst::Substs<'tcx> {
 147         let regions = self.parse_region_substs();
 148         let types = self.parse_vec_per_param_space(|this| this.parse_ty());
 149         subst::Substs { types: types, regions: regions }
 150     }
 151
 152     fn parse_region_substs(&mut self) -> subst::RegionSubsts {
 153         match self.next() {
 154             'e' => subst::ErasedRegions,
 155             'n' => {
 156                 subst::NonerasedRegions(
 157                     self.parse_vec_per_param_space(|this| this.parse_region()))
 158             }
 159             _ => panic!("parse_bound_region: bad input")
 160         }
 161     }
 162
 163     fn parse_bound_region(&mut self) -> ty::BoundRegion {
 164         match self.next() {
 165             'a' => {
 166                 let id = self.parse_u32();
 167                 assert_eq!(self.next(), '|');
 168                 ty::BrAnon(id)
 169             }
 170             '[' => {
 171                 let def = self.parse_def();
 172                 let name = token::intern(&self.parse_str(']'));
 173                 ty::BrNamed(def, name)
 174             }
 175             'f' => {
 176                 let id = self.parse_u32();
 177                 assert_eq!(self.next(), '|');
 178                 ty::BrFresh(id)
 179             }
 180             'e' => ty::BrEnv,
 181             _ => panic!("parse_bound_region: bad input")
 182         }
 183     }
 184
 185     pub fn parse_region(&mut self) -> ty::Region {
 186         match self.next() {
 187             'b' => {
 188                 assert_eq!(self.next(), '[');
 189                 let id = ty::DebruijnIndex::new(self.parse_u32());
 190                 assert_eq!(self.next(), '|');
 191                 let br = self.parse_bound_region();
 192                 assert_eq!(self.next(), ']');
 193                 ty::ReLateBound(id, br)
 194             }
 195             'B' => {
 196                 assert_eq!(self.next(), '[');
 197                 let space = self.parse_param_space();
 198                 assert_eq!(self.next(), '|');
 199                 let index = self.parse_u32();
 200                 assert_eq!(self.next(), '|');
 201                 let name = token::intern(&self.parse_str(']'));
 202                 ty::ReEarlyBound(ty::EarlyBoundRegion {
 203                     space: space,
 204                     index: index,
 205                     name: name
 206                 })
 207             }
 208             'f' => {
 209                 assert_eq!(self.next(), '[');
 210                 let scope = self.parse_scope();
 211                 assert_eq!(self.next(), '|');
 212                 let br = self.parse_bound_region();
 213                 assert_eq!(self.next(), ']');
 214                 ty::ReFree(ty::FreeRegion { scope: scope,
 215                                             bound_region: br})
 216             }
 217             's' => {
 218                 let scope = self.parse_scope();
 219                 assert_eq!(self.next(), '|');
 220                 ty::ReScope(scope)
 221             }
 222             't' => {
 223                 ty::ReStatic
 224             }
 225             'e' => {
 226                 ty::ReStatic
 227             }
 228             _ => panic!("parse_region: bad input")
 229         }
 230     }
 231
 232     fn parse_scope(&mut self) -> region::CodeExtent {
 233         self.tcx.region_maps.bogus_code_extent(match self.next() {
 234             // This creates scopes with the wrong NodeId. This isn't
 235             // actually a problem because scopes only exist *within*
 236             // functions, and functions aren't loaded until trans which
 237             // doesn't care about regions.
 238             //
 239             // May still be worth fixing though.
 240             'C' => {
 241                 assert_eq!(self.next(), '[');
 242                 let fn_id = self.parse_uint() as ast::NodeId;
 243                 assert_eq!(self.next(), '|');
 244                 let body_id = self.parse_uint() as ast::NodeId;
 245                 assert_eq!(self.next(), ']');
 246                 region::CodeExtentData::CallSiteScope {
 247                     fn_id: fn_id, body_id: body_id
 248                 }
 249             }
 250             // This creates scopes with the wrong NodeId. (See note above.)
 251             'P' => {
 252                 assert_eq!(self.next(), '[');
 253                 let fn_id = self.parse_uint() as ast::NodeId;
 254                 assert_eq!(self.next(), '|');
 255                 let body_id = self.parse_uint() as ast::NodeId;
 256                 assert_eq!(self.next(), ']');
 257                 region::CodeExtentData::ParameterScope {
 258                     fn_id: fn_id, body_id: body_id
 259                 }
 260             }
 261             'M' => {
 262                 let node_id = self.parse_uint() as ast::NodeId;
 263                 region::CodeExtentData::Misc(node_id)
 264             }
 265             'D' => {
 266                 let node_id = self.parse_uint() as ast::NodeId;
 267                 region::CodeExtentData::DestructionScope(node_id)
 268             }
 269             'B' => {
 270                 assert_eq!(self.next(), '[');
 271                 let node_id = self.parse_uint() as ast::NodeId;
 272                 assert_eq!(self.next(), '|');
 273                 let first_stmt_index = self.parse_u32();
 274                 assert_eq!(self.next(), ']');
 275                 let block_remainder = region::BlockRemainder {
 276                     block: node_id, first_statement_index: first_stmt_index,
 277                 };
 278                 region::CodeExtentData::Remainder(block_remainder)
 279             }
 280             _ => panic!("parse_scope: bad input")
 281         })
 282     }
 283
 284     fn parse_opt<T, F>(&mut self, f: F) -> Option<T>
 285         where F: FnOnce(&mut TyDecoder<'a, 'tcx>) -> T,
 286     {
 287         match self.next() {
 288             'n' => None,
 289             's' => Some(f(self)),
 290             _ => panic!("parse_opt: bad input")
 291         }
 292     }
 293
 294     fn parse_str(&mut self, term: char) -> String {
 295         let mut result = String::new();
 296         while self.peek() != term {
 297             unsafe {
 298                 result.as_mut_vec().extend_from_slice(&[self.next_byte()])
 299             }
 300         }
 301         self.next();
 302         result
 303     }
 304
 305     pub fn parse_trait_ref(&mut self) -> ty::TraitRef<'tcx> {
 306         let def = self.parse_def();
 307         let substs = self.tcx.mk_substs(self.parse_substs());
 308         ty::TraitRef {def_id: def, substs: substs}
 309     }
 310
 311     pub fn parse_ty(&mut self) -> Ty<'tcx> {
 312         let tcx = self.tcx;
 313         match self.next() {
 314             'b' => return tcx.types.bool,
 315             'i' => { /* eat the s of is */ self.next(); return tcx.types.isize },
 316             'u' => { /* eat the s of us */ self.next(); return tcx.types.usize },
 317             'M' => {
 318                 match self.next() {
 319                     'b' => return tcx.types.u8,
 320                     'w' => return tcx.types.u16,
 321                     'l' => return tcx.types.u32,
 322                     'd' => return tcx.types.u64,
 323                     'B' => return tcx.types.i8,
 324                     'W' => return tcx.types.i16,
 325                     'L' => return tcx.types.i32,
 326                     'D' => return tcx.types.i64,
 327                     'f' => return tcx.types.f32,
 328                     'F' => return tcx.types.f64,
 329                     _ => panic!("parse_ty: bad numeric type")
 330                 }
 331             }
 332             'c' => return tcx.types.char,
 333             't' => {
 334                 assert_eq!(self.next(), '[');
 335                 let did = self.parse_def();
 336                 let substs = self.parse_substs();
 337                 assert_eq!(self.next(), ']');
 338                 let def = self.tcx.lookup_adt_def(did);
 339                 return tcx.mk_enum(def, self.tcx.mk_substs(substs));
 340             }
 341             'x' => {
 342                 assert_eq!(self.next(), '[');
 343                 let trait_ref = ty::Binder(self.parse_trait_ref());
 344                 let bounds = self.parse_existential_bounds();
 345                 assert_eq!(self.next(), ']');
 346                 return tcx.mk_trait(trait_ref, bounds);
 347             }
 348             'p' => {
 349                 assert_eq!(self.next(), '[');
 350                 let index = self.parse_u32();
 351                 assert_eq!(self.next(), '|');
 352                 let space = self.parse_param_space();
 353                 assert_eq!(self.next(), '|');
 354                 let name = token::intern(&self.parse_str(']'));
 355                 return tcx.mk_param(space, index, name);
 356             }
 357             '~' => return tcx.mk_box(self.parse_ty()),
 358             '*' => return tcx.mk_ptr(self.parse_mt()),
 359             '&' => {
 360                 let r = self.parse_region();
 361                 let mt = self.parse_mt();
 362                 return tcx.mk_ref(tcx.mk_region(r), mt);
 363             }
 364             'V' => {
 365                 let t = self.parse_ty();
 366                 return match self.parse_size() {
 367                     Some(n) => tcx.mk_array(t, n),
 368                     None => tcx.mk_slice(t)
 369                 };
 370             }
 371             'v' => {
 372                 return tcx.mk_str();
 373             }
 374             'T' => {
 375                 assert_eq!(self.next(), '[');
 376                 let mut params = Vec::new();
 377                 while self.peek() != ']' { params.push(self.parse_ty()); }
 378                 self.pos = self.pos + 1;
 379                 return tcx.mk_tup(params);
 380             }
 381             'F' => {
 382                 let def_id = self.parse_def();
 383                 return tcx.mk_fn(Some(def_id), tcx.mk_bare_fn(self.parse_bare_fn_ty()));
 384             }
 385             'G' => {
 386                 return tcx.mk_fn(None, tcx.mk_bare_fn(self.parse_bare_fn_ty()));
 387             }
 388             '#' => {
 389                 // This is a hacky little caching scheme. The idea is that if we encode
 390                 // the same type twice, the second (and third, and fourth...) time we will
 391                 // just write `#123`, where `123` is the offset in the metadata of the
 392                 // first appearance. Now when we are *decoding*, if we see a `#123`, we
 393                 // can first check a cache (`tcx.rcache`) for that offset. If we find something,
 394                 // we return it (modulo closure types, see below). But if not, then we
 395                 // jump to offset 123 and read the type from there.
 396
 397                 let pos = self.parse_vuint();
 398                 let key = ty::CReaderCacheKey { cnum: self.krate, pos: pos };
 399                 match tcx.rcache.borrow().get(&key).cloned() {
 400                     Some(tt) => {
 401                         // If there is a closure buried in the type some where, then we
 402                         // need to re-convert any def ids (see case 'k', below). That means
 403                         // we can't reuse the cached version.
 404                         if !tt.has_closure_types() {
 405                             return tt;
 406                         }
 407                     }
 408                     None => {}
 409                 }
 410
 411                 let mut substate = TyDecoder::new(self.data,
 412                                                   self.krate,
 413                                                   pos,
 414                                                   self.tcx,
 415                                                   self.conv_def_id);
 416                 let tt = substate.parse_ty();
 417                 tcx.rcache.borrow_mut().insert(key, tt);
 418                 return tt;
 419             }
 420             '\"' => {
 421                 let _ = self.parse_def();
 422                 let inner = self.parse_ty();
 423                 inner
 424             }
 425             'a' => {
 426                 assert_eq!(self.next(), '[');
 427                 let did = self.parse_def();
 428                 let substs = self.parse_substs();
 429                 assert_eq!(self.next(), ']');
 430                 let def = self.tcx.lookup_adt_def(did);
 431                 return self.tcx.mk_struct(def, self.tcx.mk_substs(substs));
 432             }
 433             'k' => {
 434                 assert_eq!(self.next(), '[');
 435                 let did = self.parse_def();
 436                 let substs = self.parse_substs();
 437                 let mut tys = vec![];
 438                 while self.peek() != '.' {
 439                     tys.push(self.parse_ty());
 440                 }
 441                 assert_eq!(self.next(), '.');
 442                 assert_eq!(self.next(), ']');
 443                 return self.tcx.mk_closure(did, self.tcx.mk_substs(substs), tys);
 444             }
 445             'P' => {
 446                 assert_eq!(self.next(), '[');
 447                 let trait_ref = self.parse_trait_ref();
 448                 let name = token::intern(&self.parse_str(']'));
 449                 return tcx.mk_projection(trait_ref, name);
 450             }
 451             'e' => {
 452                 return tcx.types.err;
 453             }
 454             c => { panic!("unexpected char in type string: {}", c);}
 455         }
 456     }
 457
 458     fn parse_mutability(&mut self) -> hir::Mutability {
 459         match self.peek() {
 460             'm' => { self.next(); hir::MutMutable }
 461             _ => { hir::MutImmutable }
 462         }
 463     }
 464
 465     fn parse_mt(&mut self) -> ty::TypeAndMut<'tcx> {
 466         let m = self.parse_mutability();
 467         ty::TypeAndMut { ty: self.parse_ty(), mutbl: m }
 468     }
 469
 470     fn parse_def(&mut self) -> DefId {
 471         let def_id = parse_defid(self.scan(|c| c == '|'));
 472         return (self.conv_def_id)(def_id);
 473     }
 474
 475     fn parse_uint(&mut self) -> usize {
 476         let mut n = 0;
 477         loop {
 478             let cur = self.peek();
 479             if cur < '0' || cur > '9' { return n; }
 480             self.pos = self.pos + 1;
 481             n *= 10;
 482             n += (cur as usize) - ('0' as usize);
 483         };
 484     }
 485
 486     fn parse_u32(&mut self) -> u32 {
 487         let n = self.parse_uint();
 488         let m = n as u32;
 489         assert_eq!(m as usize, n);
 490         m
 491     }
 492
 493     fn parse_param_space(&mut self) -> subst::ParamSpace {
 494         subst::ParamSpace::from_uint(self.parse_uint())
 495     }
 496
 497     fn parse_abi_set(&mut self) -> abi::Abi {
 498         assert_eq!(self.next(), '[');
 499         let bytes = self.scan(|c| c == ']');
 500         let abi_str = str::from_utf8(bytes).unwrap();
 501         abi::lookup(&abi_str[..]).expect(abi_str)
 502     }
 503
 504     pub fn parse_closure_ty(&mut self) -> ty::ClosureTy<'tcx> {
 505         let unsafety = parse_unsafety(self.next());
 506         let sig = self.parse_sig();
 507         let abi = self.parse_abi_set();
 508         ty::ClosureTy {
 509             unsafety: unsafety,
 510             sig: sig,
 511             abi: abi,
 512         }
 513     }
 514
 515     pub fn parse_bare_fn_ty(&mut self) -> ty::BareFnTy<'tcx> {
 516         let unsafety = parse_unsafety(self.next());
 517         let abi = self.parse_abi_set();
 518         let sig = self.parse_sig();
 519         ty::BareFnTy {
 520             unsafety: unsafety,
 521             abi: abi,
 522             sig: sig
 523         }
 524     }
 525
 526     fn parse_sig(&mut self) -> ty::PolyFnSig<'tcx> {
 527         assert_eq!(self.next(), '[');
 528         let mut inputs = Vec::new();
 529         while self.peek() != ']' {
 530             inputs.push(self.parse_ty());
 531         }
 532         self.pos += 1; // eat the ']'
 533         let variadic = match self.next() {
 534             'V' => true,
 535             'N' => false,
 536             r => panic!(format!("bad variadic: {}", r)),
 537         };
 538         let output = match self.peek() {
 539             'z' => {
 540                 self.pos += 1;
 541                 ty::FnDiverging
 542             }
 543             _ => ty::FnConverging(self.parse_ty())
 544         };
 545         ty::Binder(ty::FnSig {inputs: inputs,
 546                               output: output,
 547                               variadic: variadic})
 548     }
 549
 550     pub fn parse_predicate(&mut self) -> ty::Predicate<'tcx> {
 551         match self.next() {
 552             't' => ty::Binder(self.parse_trait_ref()).to_predicate(),
 553             'e' => ty::Binder(ty::EquatePredicate(self.parse_ty(),
 554                                                   self.parse_ty())).to_predicate(),
 555             'r' => ty::Binder(ty::OutlivesPredicate(self.parse_region(),
 556                                                     self.parse_region())).to_predicate(),
 557             'o' => ty::Binder(ty::OutlivesPredicate(self.parse_ty(),
 558                                                     self.parse_region())).to_predicate(),
 559             'p' => ty::Binder(self.parse_projection_predicate()).to_predicate(),
 560             'w' => ty::Predicate::WellFormed(self.parse_ty()),
 561             'O' => {
 562                 let def_id = self.parse_def();
 563                 assert_eq!(self.next(), '|');
 564                 ty::Predicate::ObjectSafe(def_id)
 565             }
 566             c => panic!("Encountered invalid character in metadata: {}", c)
 567         }
 568     }
 569
 570     fn parse_projection_predicate(&mut self) -> ty::ProjectionPredicate<'tcx> {
 571         ty::ProjectionPredicate {
 572             projection_ty: ty::ProjectionTy {
 573                 trait_ref: self.parse_trait_ref(),
 574                 item_name: token::intern(&self.parse_str('|')),
 575             },
 576             ty: self.parse_ty(),
 577         }
 578     }
 579
 580     pub fn parse_type_param_def(&mut self) -> ty::TypeParameterDef<'tcx> {
 581         let name = self.parse_name(':');
 582         let def_id = self.parse_def();
 583         let space = self.parse_param_space();
 584         assert_eq!(self.next(), '|');
 585         let index = self.parse_u32();
 586         assert_eq!(self.next(), '|');
 587         let default_def_id = self.parse_def();
 588         let default = self.parse_opt(|this| this.parse_ty());
 589         let object_lifetime_default = self.parse_object_lifetime_default();
 590
 591         ty::TypeParameterDef {
 592             name: name,
 593             def_id: def_id,
 594             space: space,
 595             index: index,
 596             default_def_id: default_def_id,
 597             default: default,
 598             object_lifetime_default: object_lifetime_default,
 599         }
 600     }
 601
 602     pub fn parse_region_param_def(&mut self) -> ty::RegionParameterDef {
 603         let name = self.parse_name(':');
 604         let def_id = self.parse_def();
 605         let space = self.parse_param_space();
 606         assert_eq!(self.next(), '|');
 607         let index = self.parse_u32();
 608         assert_eq!(self.next(), '|');
 609         let mut bounds = vec![];
 610         loop {
 611             match self.next() {
 612                 'R' => bounds.push(self.parse_region()),
 613                 '.' => { break; }
 614                 c => {
 615                     panic!("parse_region_param_def: bad bounds ('{}')", c)
 616                 }
 617             }
 618         }
 619         ty::RegionParameterDef {
 620             name: name,
 621             def_id: def_id,
 622             space: space,
 623             index: index,
 624             bounds: bounds
 625         }
 626     }
 627
 628
 629     fn parse_object_lifetime_default(&mut self) -> ty::ObjectLifetimeDefault {
 630         match self.next() {
 631             'a' => ty::ObjectLifetimeDefault::Ambiguous,
 632             'b' => ty::ObjectLifetimeDefault::BaseDefault,
 633             's' => {
 634                 let region = self.parse_region();
 635                 ty::ObjectLifetimeDefault::Specific(region)
 636             }
 637             _ => panic!("parse_object_lifetime_default: bad input")
 638         }
 639     }
 640
 641     pub fn parse_existential_bounds(&mut self) -> ty::ExistentialBounds<'tcx> {
 642         let builtin_bounds = self.parse_builtin_bounds();
 643         let region_bound = self.parse_region();
 644         let mut projection_bounds = Vec::new();
 645
 646         loop {
 647             match self.next() {
 648                 'P' => {
 649                     projection_bounds.push(ty::Binder(self.parse_projection_predicate()));
 650                 }
 651                 '.' => { break; }
 652                 c => {
 653                     panic!("parse_bounds: bad bounds ('{}')", c)
 654                 }
 655             }
 656         }
 657
 658         ty::ExistentialBounds::new(
 659             region_bound, builtin_bounds, projection_bounds)
 660     }
 661
 662     fn parse_builtin_bounds(&mut self) -> ty::BuiltinBounds {
 663         let mut builtin_bounds = ty::BuiltinBounds::empty();
 664         loop {
 665             match self.next() {
 666                 'S' => {
 667                     builtin_bounds.insert(ty::BoundSend);
 668                 }
 669                 'Z' => {
 670                     builtin_bounds.insert(ty::BoundSized);
 671                 }
 672                 'P' => {
 673                     builtin_bounds.insert(ty::BoundCopy);
 674                 }
 675                 'T' => {
 676                     builtin_bounds.insert(ty::BoundSync);
 677                 }
 678                 '.' => {
 679                     return builtin_bounds;
 680                 }
 681                 c => {
 682                     panic!("parse_bounds: bad builtin bounds ('{}')", c)
 683                 }
 684             }
 685         }
 686     }
 687 }
 688
 689 // Rust metadata parsing
 690 fn parse_defid(buf: &[u8]) -> DefId {
 691     let mut colon_idx = 0;
 692     let len = buf.len();
 693     while colon_idx < len && buf[colon_idx] != ':' as u8 { colon_idx += 1; }
 694     if colon_idx == len {
 695         error!("didn't find ':' when parsing def id");
 696         panic!();
 697     }
 698
 699     let crate_part = &buf[0..colon_idx];
 700     let def_part = &buf[colon_idx + 1..len];
 701
 702     let crate_num = match str::from_utf8(crate_part).ok().and_then(|s| {
 703         s.parse::<usize>().ok()
 704     }) {
 705         Some(cn) => cn as ast::CrateNum,
 706         None => panic!("internal error: parse_defid: crate number expected, found {:?}",
 707                        crate_part)
 708     };
 709     let def_num = match str::from_utf8(def_part).ok().and_then(|s| {
 710         s.parse::<usize>().ok()
 711     }) {
 712         Some(dn) => dn,
 713         None => panic!("internal error: parse_defid: id expected, found {:?}",
 714                        def_part)
 715     };
 716     let index = DefIndex::new(def_num);
 717     DefId { krate: crate_num, index: index }
 718 }
 719
 720 fn parse_unsafety(c: char) -> hir::Unsafety {
 721     match c {
 722         'u' => hir::Unsafety::Unsafe,
 723         'n' => hir::Unsafety::Normal,
 724         _ => panic!("parse_unsafety: bad unsafety {}", c)
 725     }
 726 }