src/librustc/middle/astencode.rs

   1 // Copyright 2012-2015 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 #![allow(non_camel_case_types)]
  12 // FIXME: remove this after snapshot, and Results are handled
  13 #![allow(unused_must_use)]
  14
  15 use metadata::common as c;
  16 use metadata::cstore as cstore;
  17 use session::Session;
  18 use metadata::decoder;
  19 use middle::def;
  20 use metadata::encoder as e;
  21 use middle::region;
  22 use metadata::tydecode;
  23 use metadata::tydecode::{DefIdSource, NominalType, TypeWithId, TypeParameter};
  24 use metadata::tydecode::{RegionParameter, ClosureSource};
  25 use metadata::tyencode;
  26 use middle::check_const::ConstQualif;
  27 use middle::mem_categorization::Typer;
  28 use middle::privacy::{AllPublic, LastMod};
  29 use middle::subst;
  30 use middle::subst::VecPerParamSpace;
  31 use middle::ty::{self, Ty, MethodCall, MethodCallee, MethodOrigin};
  32 use util::ppaux::ty_to_string;
  33
  34 use syntax::{ast, ast_map, ast_util, codemap, fold};
  35 use syntax::codemap::Span;
  36 use syntax::fold::Folder;
  37 use syntax::parse::token;
  38 use syntax::ptr::P;
  39 use syntax;
  40
  41 use std::cell::Cell;
  42 use std::io::SeekFrom;
  43 use std::io::prelude::*;
  44 use std::num::FromPrimitive;
  45 use std::rc::Rc;
  46 use std::fmt::Debug;
  47
  48 use rbml::reader;
  49 use rbml::writer::Encoder;
  50 use rbml;
  51 use serialize;
  52 use serialize::{Decodable, Decoder, DecoderHelpers, Encodable};
  53 use serialize::{EncoderHelpers};
  54
  55 #[cfg(test)] use std::io::Cursor;
  56 #[cfg(test)] use syntax::parse;
  57 #[cfg(test)] use syntax::print::pprust;
  58
  59 struct DecodeContext<'a, 'b, 'tcx: 'a> {
  60     tcx: &'a ty::ctxt<'tcx>,
  61     cdata: &'b cstore::crate_metadata,
  62     from_id_range: ast_util::IdRange,
  63     to_id_range: ast_util::IdRange,
  64     // Cache the last used filemap for translating spans as an optimization.
  65     last_filemap_index: Cell<usize>,
  66 }
  67
  68 trait tr {
  69     fn tr(&self, dcx: &DecodeContext) -> Self;
  70 }
  71
  72 trait tr_intern {
  73     fn tr_intern(&self, dcx: &DecodeContext) -> ast::DefId;
  74 }
  75
  76 // ______________________________________________________________________
  77 // Top-level methods.
  78
  79 pub fn encode_inlined_item(ecx: &e::EncodeContext,
  80                            rbml_w: &mut Encoder,
  81                            ii: e::InlinedItemRef) {
  82     let id = match ii {
  83         e::IIItemRef(i) => i.id,
  84         e::IIForeignRef(i) => i.id,
  85         e::IITraitItemRef(_, ti) => ti.id,
  86         e::IIImplItemRef(_, ii) => ii.id,
  87     };
  88     debug!("> Encoding inlined item: {} ({:?})",
  89            ecx.tcx.map.path_to_string(id),
  90            rbml_w.writer.seek(SeekFrom::Current(0)));
  91
  92     // Folding could be avoided with a smarter encoder.
  93     let ii = simplify_ast(ii);
  94     let id_range = ast_util::compute_id_range_for_inlined_item(&ii);
  95
  96     rbml_w.start_tag(c::tag_ast as uint);
  97     id_range.encode(rbml_w);
  98     encode_ast(rbml_w, &ii);
  99     encode_side_tables_for_ii(ecx, rbml_w, &ii);
 100     rbml_w.end_tag();
 101
 102     debug!("< Encoded inlined fn: {} ({:?})",
 103            ecx.tcx.map.path_to_string(id),
 104            rbml_w.writer.seek(SeekFrom::Current(0)));
 105 }
 106
 107 impl<'a, 'b, 'c, 'tcx> ast_map::FoldOps for &'a DecodeContext<'b, 'c, 'tcx> {
 108     fn new_id(&self, id: ast::NodeId) -> ast::NodeId {
 109         if id == ast::DUMMY_NODE_ID {
 110             // Used by ast_map to map the NodeInlinedParent.
 111             self.tcx.sess.next_node_id()
 112         } else {
 113             self.tr_id(id)
 114         }
 115     }
 116     fn new_def_id(&self, def_id: ast::DefId) -> ast::DefId {
 117         self.tr_def_id(def_id)
 118     }
 119     fn new_span(&self, span: Span) -> Span {
 120         self.tr_span(span)
 121     }
 122 }
 123
 124 /// Decodes an item from its AST in the cdata's metadata and adds it to the
 125 /// ast-map.
 126 pub fn decode_inlined_item<'tcx>(cdata: &cstore::crate_metadata,
 127                                  tcx: &ty::ctxt<'tcx>,
 128                                  path: Vec<ast_map::PathElem>,
 129                                  par_doc: rbml::Doc)
 130                                  -> Result<&'tcx ast::InlinedItem, Vec<ast_map::PathElem>> {
 131     match par_doc.opt_child(c::tag_ast) {
 132       None => Err(path),
 133       Some(ast_doc) => {
 134         let mut path_as_str = None;
 135         debug!("> Decoding inlined fn: {:?}::?",
 136         {
 137             // Do an Option dance to use the path after it is moved below.
 138             let s = ast_map::path_to_string(path.iter().cloned());
 139             path_as_str = Some(s);
 140             path_as_str.as_ref().map(|x| &x[..])
 141         });
 142         let mut ast_dsr = reader::Decoder::new(ast_doc);
 143         let from_id_range = Decodable::decode(&mut ast_dsr).unwrap();
 144         let to_id_range = reserve_id_range(&tcx.sess, from_id_range);
 145         let dcx = &DecodeContext {
 146             cdata: cdata,
 147             tcx: tcx,
 148             from_id_range: from_id_range,
 149             to_id_range: to_id_range,
 150             last_filemap_index: Cell::new(0)
 151         };
 152         let raw_ii = decode_ast(ast_doc);
 153         let ii = ast_map::map_decoded_item(&dcx.tcx.map, path, raw_ii, dcx);
 154
 155         let ident = match *ii {
 156             ast::IIItem(ref i) => i.ident,
 157             ast::IIForeign(ref i) => i.ident,
 158             ast::IITraitItem(_, ref ti) => ti.ident,
 159             ast::IIImplItem(_, ref ii) => ii.ident
 160         };
 161         debug!("Fn named: {}", token::get_ident(ident));
 162         debug!("< Decoded inlined fn: {}::{}",
 163                path_as_str.unwrap(),
 164                token::get_ident(ident));
 165         region::resolve_inlined_item(&tcx.sess, &tcx.region_maps, ii);
 166         decode_side_tables(dcx, ast_doc);
 167         match *ii {
 168           ast::IIItem(ref i) => {
 169             debug!(">>> DECODED ITEM >>>\n{}\n<<< DECODED ITEM <<<",
 170                    syntax::print::pprust::item_to_string(&**i));
 171           }
 172           _ => { }
 173         }
 174         Ok(ii)
 175       }
 176     }
 177 }
 178
 179 // ______________________________________________________________________
 180 // Enumerating the IDs which appear in an AST
 181
 182 fn reserve_id_range(sess: &Session,
 183                     from_id_range: ast_util::IdRange) -> ast_util::IdRange {
 184     // Handle the case of an empty range:
 185     if from_id_range.empty() { return from_id_range; }
 186     let cnt = from_id_range.max - from_id_range.min;
 187     let to_id_min = sess.reserve_node_ids(cnt);
 188     let to_id_max = to_id_min + cnt;
 189     ast_util::IdRange { min: to_id_min, max: to_id_max }
 190 }
 191
 192 impl<'a, 'b, 'tcx> DecodeContext<'a, 'b, 'tcx> {
 193     /// Translates an internal id, meaning a node id that is known to refer to some part of the
 194     /// item currently being inlined, such as a local variable or argument.  All naked node-ids
 195     /// that appear in types have this property, since if something might refer to an external item
 196     /// we would use a def-id to allow for the possibility that the item resides in another crate.
 197     pub fn tr_id(&self, id: ast::NodeId) -> ast::NodeId {
 198         // from_id_range should be non-empty
 199         assert!(!self.from_id_range.empty());
 200         // Use wrapping arithmetic because otherwise it introduces control flow.
 201         // Maybe we should just have the control flow? -- aatch
 202         (id.wrapping_sub(self.from_id_range.min).wrapping_add(self.to_id_range.min))
 203     }
 204
 205     /// Translates an EXTERNAL def-id, converting the crate number from the one used in the encoded
 206     /// data to the current crate numbers..  By external, I mean that it be translated to a
 207     /// reference to the item in its original crate, as opposed to being translated to a reference
 208     /// to the inlined version of the item.  This is typically, but not always, what you want,
 209     /// because most def-ids refer to external things like types or other fns that may or may not
 210     /// be inlined.  Note that even when the inlined function is referencing itself recursively, we
 211     /// would want `tr_def_id` for that reference--- conceptually the function calls the original,
 212     /// non-inlined version, and trans deals with linking that recursive call to the inlined copy.
 213     ///
 214     /// However, there are a *few* cases where def-ids are used but we know that the thing being
 215     /// referenced is in fact *internal* to the item being inlined.  In those cases, you should use
 216     /// `tr_intern_def_id()` below.
 217     pub fn tr_def_id(&self, did: ast::DefId) -> ast::DefId {
 218
 219         decoder::translate_def_id(self.cdata, did)
 220     }
 221
 222     /// Translates an INTERNAL def-id, meaning a def-id that is
 223     /// known to refer to some part of the item currently being
 224     /// inlined.  In that case, we want to convert the def-id to
 225     /// refer to the current crate and to the new, inlined node-id.
 226     pub fn tr_intern_def_id(&self, did: ast::DefId) -> ast::DefId {
 227         assert_eq!(did.krate, ast::LOCAL_CRATE);
 228         ast::DefId { krate: ast::LOCAL_CRATE, node: self.tr_id(did.node) }
 229     }
 230
 231     /// Translates a `Span` from an extern crate to the corresponding `Span`
 232     /// within the local crate's codemap. `creader::import_codemap()` will
 233     /// already have allocated any additionally needed FileMaps in the local
 234     /// codemap as a side-effect of creating the crate_metadata's
 235     /// `codemap_import_info`.
 236     pub fn tr_span(&self, span: Span) -> Span {
 237         let imported_filemaps = &self.cdata.codemap_import_info[..];
 238
 239         let span = if span.lo > span.hi {
 240             // Currently macro expansion sometimes produces invalid Span values
 241             // where lo > hi. In order not to crash the compiler when trying to
 242             // translate these values, let's transform them into something we
 243             // can handle (and which will produce useful debug locations at
 244             // least some of the time).
 245             // This workaround is only necessary as long as macro expansion is
 246             // not fixed. FIXME(#23480)
 247             codemap::mk_sp(span.lo, span.lo)
 248         } else {
 249             span
 250         };
 251
 252         let filemap_index = {
 253             // Optimize for the case that most spans within a translated item
 254             // originate from the same filemap.
 255             let last_filemap_index = self.last_filemap_index.get();
 256
 257             if span.lo >= imported_filemaps[last_filemap_index].original_start_pos &&
 258                span.lo <= imported_filemaps[last_filemap_index].original_end_pos &&
 259                span.hi >= imported_filemaps[last_filemap_index].original_start_pos &&
 260                span.hi <= imported_filemaps[last_filemap_index].original_end_pos {
 261                 last_filemap_index
 262             } else {
 263                 let mut a = 0;
 264                 let mut b = imported_filemaps.len();
 265
 266                 while b - a > 1 {
 267                     let m = (a + b) / 2;
 268                     if imported_filemaps[m].original_start_pos > span.lo {
 269                         b = m;
 270                     } else {
 271                         a = m;
 272                     }
 273                 }
 274
 275                 self.last_filemap_index.set(a);
 276                 a
 277             }
 278         };
 279
 280         let lo = (span.lo - imported_filemaps[filemap_index].original_start_pos) +
 281                   imported_filemaps[filemap_index].translated_filemap.start_pos;
 282         let hi = (span.hi - imported_filemaps[filemap_index].original_start_pos) +
 283                   imported_filemaps[filemap_index].translated_filemap.start_pos;
 284
 285         codemap::mk_sp(lo, hi)
 286     }
 287 }
 288
 289 impl tr_intern for ast::DefId {
 290     fn tr_intern(&self, dcx: &DecodeContext) -> ast::DefId {
 291         dcx.tr_intern_def_id(*self)
 292     }
 293 }
 294
 295 impl tr for ast::DefId {
 296     fn tr(&self, dcx: &DecodeContext) -> ast::DefId {
 297         dcx.tr_def_id(*self)
 298     }
 299 }
 300
 301 impl tr for Option<ast::DefId> {
 302     fn tr(&self, dcx: &DecodeContext) -> Option<ast::DefId> {
 303         self.map(|d| dcx.tr_def_id(d))
 304     }
 305 }
 306
 307 impl tr for Span {
 308     fn tr(&self, dcx: &DecodeContext) -> Span {
 309         dcx.tr_span(*self)
 310     }
 311 }
 312
 313 trait def_id_encoder_helpers {
 314     fn emit_def_id(&mut self, did: ast::DefId);
 315 }
 316
 317 impl<S:serialize::Encoder> def_id_encoder_helpers for S
 318     where <S as serialize::serialize::Encoder>::Error: Debug
 319 {
 320     fn emit_def_id(&mut self, did: ast::DefId) {
 321         did.encode(self).unwrap()
 322     }
 323 }
 324
 325 trait def_id_decoder_helpers {
 326     fn read_def_id(&mut self, dcx: &DecodeContext) -> ast::DefId;
 327     fn read_def_id_nodcx(&mut self,
 328                          cdata: &cstore::crate_metadata) -> ast::DefId;
 329 }
 330
 331 impl<D:serialize::Decoder> def_id_decoder_helpers for D
 332     where <D as serialize::serialize::Decoder>::Error: Debug
 333 {
 334     fn read_def_id(&mut self, dcx: &DecodeContext) -> ast::DefId {
 335         let did: ast::DefId = Decodable::decode(self).unwrap();
 336         did.tr(dcx)
 337     }
 338
 339     fn read_def_id_nodcx(&mut self,
 340                          cdata: &cstore::crate_metadata)
 341                          -> ast::DefId {
 342         let did: ast::DefId = Decodable::decode(self).unwrap();
 343         decoder::translate_def_id(cdata, did)
 344     }
 345 }
 346
 347 // ______________________________________________________________________
 348 // Encoding and decoding the AST itself
 349 //
 350 // The hard work is done by an autogenerated module astencode_gen.  To
 351 // regenerate astencode_gen, run src/etc/gen-astencode.  It will
 352 // replace astencode_gen with a dummy file and regenerate its
 353 // contents.  If you get compile errors, the dummy file
 354 // remains---resolve the errors and then rerun astencode_gen.
 355 // Annoying, I know, but hopefully only temporary.
 356 //
 357 // When decoding, we have to renumber the AST so that the node ids that
 358 // appear within are disjoint from the node ids in our existing ASTs.
 359 // We also have to adjust the spans: for now we just insert a dummy span,
 360 // but eventually we should add entries to the local codemap as required.
 361
 362 fn encode_ast(rbml_w: &mut Encoder, item: &ast::InlinedItem) {
 363     rbml_w.start_tag(c::tag_tree as uint);
 364     item.encode(rbml_w);
 365     rbml_w.end_tag();
 366 }
 367
 368 struct NestedItemsDropper;
 369
 370 impl Folder for NestedItemsDropper {
 371     fn fold_block(&mut self, blk: P<ast::Block>) -> P<ast::Block> {
 372         blk.and_then(|ast::Block {id, stmts, expr, rules, span, ..}| {
 373             let stmts_sans_items = stmts.into_iter().filter_map(|stmt| {
 374                 let use_stmt = match stmt.node {
 375                     ast::StmtExpr(_, _) | ast::StmtSemi(_, _) => true,
 376                     ast::StmtDecl(ref decl, _) => {
 377                         match decl.node {
 378                             ast::DeclLocal(_) => true,
 379                             ast::DeclItem(_) => false,
 380                         }
 381                     }
 382                     ast::StmtMac(..) => panic!("unexpanded macro in astencode")
 383                 };
 384                 if use_stmt {
 385                     Some(stmt)
 386                 } else {
 387                     None
 388                 }
 389             }).collect();
 390             let blk_sans_items = P(ast::Block {
 391                 stmts: stmts_sans_items,
 392                 expr: expr,
 393                 id: id,
 394                 rules: rules,
 395                 span: span,
 396             });
 397             fold::noop_fold_block(blk_sans_items, self)
 398         })
 399     }
 400 }
 401
 402 // Produces a simplified copy of the AST which does not include things
 403 // that we do not need to or do not want to export.  For example, we
 404 // do not include any nested items: if these nested items are to be
 405 // inlined, their AST will be exported separately (this only makes
 406 // sense because, in Rust, nested items are independent except for
 407 // their visibility).
 408 //
 409 // As it happens, trans relies on the fact that we do not export
 410 // nested items, as otherwise it would get confused when translating
 411 // inlined items.
 412 fn simplify_ast(ii: e::InlinedItemRef) -> ast::InlinedItem {
 413     let mut fld = NestedItemsDropper;
 414
 415     match ii {
 416         // HACK we're not dropping items.
 417         e::IIItemRef(i) => {
 418             ast::IIItem(fold::noop_fold_item(P(i.clone()), &mut fld)
 419                             .expect_one("expected one item"))
 420         }
 421         e::IITraitItemRef(d, ti) => {
 422             ast::IITraitItem(d,
 423                 fold::noop_fold_trait_item(P(ti.clone()), &mut fld)
 424                     .expect_one("noop_fold_trait_item must produce \
 425                                  exactly one trait item"))
 426         }
 427         e::IIImplItemRef(d, ii) => {
 428             ast::IIImplItem(d,
 429                 fold::noop_fold_impl_item(P(ii.clone()), &mut fld)
 430                     .expect_one("noop_fold_impl_item must produce \
 431                                  exactly one impl item"))
 432         }
 433         e::IIForeignRef(i) => {
 434             ast::IIForeign(fold::noop_fold_foreign_item(P(i.clone()), &mut fld))
 435         }
 436     }
 437 }
 438
 439 fn decode_ast(par_doc: rbml::Doc) -> ast::InlinedItem {
 440     let chi_doc = par_doc.get(c::tag_tree as uint);
 441     let mut d = reader::Decoder::new(chi_doc);
 442     Decodable::decode(&mut d).unwrap()
 443 }
 444
 445 // ______________________________________________________________________
 446 // Encoding and decoding of ast::def
 447
 448 fn decode_def(dcx: &DecodeContext, dsr: &mut reader::Decoder) -> def::Def {
 449     let def: def::Def = Decodable::decode(dsr).unwrap();
 450     def.tr(dcx)
 451 }
 452
 453 impl tr for def::Def {
 454     fn tr(&self, dcx: &DecodeContext) -> def::Def {
 455         match *self {
 456           def::DefFn(did, is_ctor) => def::DefFn(did.tr(dcx), is_ctor),
 457           def::DefMethod(did, p) => {
 458             def::DefMethod(did.tr(dcx), p.map(|did2| did2.tr(dcx)))
 459           }
 460           def::DefSelfTy(nid) => { def::DefSelfTy(dcx.tr_id(nid)) }
 461           def::DefMod(did) => { def::DefMod(did.tr(dcx)) }
 462           def::DefForeignMod(did) => { def::DefForeignMod(did.tr(dcx)) }
 463           def::DefStatic(did, m) => { def::DefStatic(did.tr(dcx), m) }
 464           def::DefConst(did) => { def::DefConst(did.tr(dcx)) }
 465           def::DefLocal(nid) => { def::DefLocal(dcx.tr_id(nid)) }
 466           def::DefVariant(e_did, v_did, is_s) => {
 467             def::DefVariant(e_did.tr(dcx), v_did.tr(dcx), is_s)
 468           },
 469           def::DefTrait(did) => def::DefTrait(did.tr(dcx)),
 470           def::DefTy(did, is_enum) => def::DefTy(did.tr(dcx), is_enum),
 471           def::DefAssociatedTy(trait_did, did) =>
 472               def::DefAssociatedTy(trait_did.tr(dcx), did.tr(dcx)),
 473           def::DefPrimTy(p) => def::DefPrimTy(p),
 474           def::DefTyParam(s, index, def_id, n) => def::DefTyParam(s, index, def_id.tr(dcx), n),
 475           def::DefUse(did) => def::DefUse(did.tr(dcx)),
 476           def::DefUpvar(nid1, nid2) => {
 477             def::DefUpvar(dcx.tr_id(nid1), dcx.tr_id(nid2))
 478           }
 479           def::DefStruct(did) => def::DefStruct(did.tr(dcx)),
 480           def::DefRegion(nid) => def::DefRegion(dcx.tr_id(nid)),
 481           def::DefLabel(nid) => def::DefLabel(dcx.tr_id(nid))
 482         }
 483     }
 484 }
 485
 486 // ______________________________________________________________________
 487 // Encoding and decoding of ancillary information
 488
 489 impl tr for ty::Region {
 490     fn tr(&self, dcx: &DecodeContext) -> ty::Region {
 491         match *self {
 492             ty::ReLateBound(debruijn, br) => {
 493                 ty::ReLateBound(debruijn, br.tr(dcx))
 494             }
 495             ty::ReEarlyBound(id, space, index, ident) => {
 496                 ty::ReEarlyBound(dcx.tr_id(id), space, index, ident)
 497             }
 498             ty::ReScope(scope) => {
 499                 ty::ReScope(scope.tr(dcx))
 500             }
 501             ty::ReEmpty | ty::ReStatic | ty::ReInfer(..) => {
 502                 *self
 503             }
 504             ty::ReFree(ref fr) => {
 505                 ty::ReFree(fr.tr(dcx))
 506             }
 507         }
 508     }
 509 }
 510
 511 impl tr for ty::FreeRegion {
 512     fn tr(&self, dcx: &DecodeContext) -> ty::FreeRegion {
 513         ty::FreeRegion { scope: self.scope.tr(dcx),
 514                          bound_region: self.bound_region.tr(dcx) }
 515     }
 516 }
 517
 518 impl tr for region::CodeExtent {
 519     fn tr(&self, dcx: &DecodeContext) -> region::CodeExtent {
 520         self.map_id(|id| dcx.tr_id(id))
 521     }
 522 }
 523
 524 impl tr for region::DestructionScopeData {
 525     fn tr(&self, dcx: &DecodeContext) -> region::DestructionScopeData {
 526         region::DestructionScopeData { node_id: dcx.tr_id(self.node_id) }
 527     }
 528 }
 529
 530 impl tr for ty::BoundRegion {
 531     fn tr(&self, dcx: &DecodeContext) -> ty::BoundRegion {
 532         match *self {
 533             ty::BrAnon(_) |
 534             ty::BrFresh(_) |
 535             ty::BrEnv => *self,
 536             ty::BrNamed(id, ident) => ty::BrNamed(dcx.tr_def_id(id),
 537                                                     ident),
 538         }
 539     }
 540 }
 541
 542 // ______________________________________________________________________
 543 // Encoding and decoding of freevar information
 544
 545 fn encode_freevar_entry(rbml_w: &mut Encoder, fv: &ty::Freevar) {
 546     (*fv).encode(rbml_w).unwrap();
 547 }
 548
 549 trait rbml_decoder_helper {
 550     fn read_freevar_entry(&mut self, dcx: &DecodeContext)
 551                           -> ty::Freevar;
 552     fn read_capture_mode(&mut self) -> ast::CaptureClause;
 553 }
 554
 555 impl<'a> rbml_decoder_helper for reader::Decoder<'a> {
 556     fn read_freevar_entry(&mut self, dcx: &DecodeContext)
 557                           -> ty::Freevar {
 558         let fv: ty::Freevar = Decodable::decode(self).unwrap();
 559         fv.tr(dcx)
 560     }
 561
 562     fn read_capture_mode(&mut self) -> ast::CaptureClause {
 563         let cm: ast::CaptureClause = Decodable::decode(self).unwrap();
 564         cm
 565     }
 566 }
 567
 568 impl tr for ty::Freevar {
 569     fn tr(&self, dcx: &DecodeContext) -> ty::Freevar {
 570         ty::Freevar {
 571             def: self.def.tr(dcx),
 572             span: self.span.tr(dcx),
 573         }
 574     }
 575 }
 576
 577 impl tr for ty::UpvarBorrow {
 578     fn tr(&self, dcx: &DecodeContext) -> ty::UpvarBorrow {
 579         ty::UpvarBorrow {
 580             kind: self.kind,
 581             region: self.region.tr(dcx)
 582         }
 583     }
 584 }
 585
 586 impl tr for ty::UpvarCapture {
 587     fn tr(&self, dcx: &DecodeContext) -> ty::UpvarCapture {
 588         match *self {
 589             ty::UpvarCapture::ByValue => ty::UpvarCapture::ByValue,
 590             ty::UpvarCapture::ByRef(ref data) => ty::UpvarCapture::ByRef(data.tr(dcx)),
 591         }
 592     }
 593 }
 594
 595 // ______________________________________________________________________
 596 // Encoding and decoding of MethodCallee
 597
 598 trait read_method_callee_helper<'tcx> {
 599     fn read_method_callee<'a, 'b>(&mut self, dcx: &DecodeContext<'a, 'b, 'tcx>)
 600         -> (ty::ExprAdjustment, MethodCallee<'tcx>);
 601 }
 602
 603 fn encode_method_callee<'a, 'tcx>(ecx: &e::EncodeContext<'a, 'tcx>,
 604                                   rbml_w: &mut Encoder,
 605                                   adjustment: ty::ExprAdjustment,
 606                                   method: &MethodCallee<'tcx>) {
 607     use serialize::Encoder;
 608
 609     rbml_w.emit_struct("MethodCallee", 4, |rbml_w| {
 610         rbml_w.emit_struct_field("adjustment", 0, |rbml_w| {
 611             adjustment.encode(rbml_w)
 612         });
 613         rbml_w.emit_struct_field("origin", 1, |rbml_w| {
 614             Ok(rbml_w.emit_method_origin(ecx, &method.origin))
 615         });
 616         rbml_w.emit_struct_field("ty", 2, |rbml_w| {
 617             Ok(rbml_w.emit_ty(ecx, method.ty))
 618         });
 619         rbml_w.emit_struct_field("substs", 3, |rbml_w| {
 620             Ok(rbml_w.emit_substs(ecx, &method.substs))
 621         })
 622     }).unwrap();
 623 }
 624
 625 impl<'a, 'tcx> read_method_callee_helper<'tcx> for reader::Decoder<'a> {
 626     fn read_method_callee<'b, 'c>(&mut self, dcx: &DecodeContext<'b, 'c, 'tcx>)
 627         -> (ty::ExprAdjustment, MethodCallee<'tcx>) {
 628
 629         self.read_struct("MethodCallee", 4, |this| {
 630             let adjustment = this.read_struct_field("adjustment", 0, |this| {
 631                 Decodable::decode(this)
 632             }).unwrap();
 633             Ok((adjustment, MethodCallee {
 634                 origin: this.read_struct_field("origin", 1, |this| {
 635                     Ok(this.read_method_origin(dcx))
 636                 }).unwrap(),
 637                 ty: this.read_struct_field("ty", 2, |this| {
 638                     Ok(this.read_ty(dcx))
 639                 }).unwrap(),
 640                 substs: this.read_struct_field("substs", 3, |this| {
 641                     Ok(this.read_substs(dcx))
 642                 }).unwrap()
 643             }))
 644         }).unwrap()
 645     }
 646 }
 647
 648 impl<'tcx> tr for MethodOrigin<'tcx> {
 649     fn tr(&self, dcx: &DecodeContext) -> MethodOrigin<'tcx> {
 650         match *self {
 651             ty::MethodStatic(did) => ty::MethodStatic(did.tr(dcx)),
 652             ty::MethodStaticClosure(did) => {
 653                 ty::MethodStaticClosure(did.tr(dcx))
 654             }
 655             ty::MethodTypeParam(ref mp) => {
 656                 ty::MethodTypeParam(
 657                     ty::MethodParam {
 658                         // def-id is already translated when we read it out
 659                         trait_ref: mp.trait_ref.clone(),
 660                         method_num: mp.method_num,
 661                         impl_def_id: mp.impl_def_id.tr(dcx),
 662                     }
 663                 )
 664             }
 665             ty::MethodTraitObject(ref mo) => {
 666                 ty::MethodTraitObject(
 667                     ty::MethodObject {
 668                         trait_ref: mo.trait_ref.clone(),
 669                         .. *mo
 670                     }
 671                 )
 672             }
 673         }
 674     }
 675 }
 676
 677 pub fn encode_closure_kind(ebml_w: &mut Encoder, kind: ty::ClosureKind) {
 678     kind.encode(ebml_w).unwrap();
 679 }
 680
 681 pub trait vtable_decoder_helpers<'tcx> {
 682     fn read_vec_per_param_space<T, F>(&mut self, f: F) -> VecPerParamSpace<T> where
 683         F: FnMut(&mut Self) -> T;
 684     fn read_vtable_res_with_key(&mut self,
 685                                 tcx: &ty::ctxt<'tcx>,
 686                                 cdata: &cstore::crate_metadata)
 687                                 -> (ty::ExprAdjustment, ty::vtable_res<'tcx>);
 688     fn read_vtable_res(&mut self,
 689                        tcx: &ty::ctxt<'tcx>, cdata: &cstore::crate_metadata)
 690                       -> ty::vtable_res<'tcx>;
 691     fn read_vtable_param_res(&mut self,
 692                        tcx: &ty::ctxt<'tcx>, cdata: &cstore::crate_metadata)
 693                       -> ty::vtable_param_res<'tcx>;
 694     fn read_vtable_origin(&mut self,
 695                           tcx: &ty::ctxt<'tcx>, cdata: &cstore::crate_metadata)
 696                           -> ty::vtable_origin<'tcx>;
 697 }
 698
 699 impl<'tcx, 'a> vtable_decoder_helpers<'tcx> for reader::Decoder<'a> {
 700     fn read_vec_per_param_space<T, F>(&mut self, mut f: F) -> VecPerParamSpace<T> where
 701         F: FnMut(&mut reader::Decoder<'a>) -> T,
 702     {
 703         let types = self.read_to_vec(|this| Ok(f(this))).unwrap();
 704         let selfs = self.read_to_vec(|this| Ok(f(this))).unwrap();
 705         let fns = self.read_to_vec(|this| Ok(f(this))).unwrap();
 706         VecPerParamSpace::new(types, selfs, fns)
 707     }
 708
 709     fn read_vtable_res_with_key(&mut self,
 710                                 tcx: &ty::ctxt<'tcx>,
 711                                 cdata: &cstore::crate_metadata)
 712                                 -> (ty::ExprAdjustment, ty::vtable_res<'tcx>) {
 713         self.read_struct("VtableWithKey", 2, |this| {
 714             let adjustment = this.read_struct_field("adjustment", 0, |this| {
 715                 Decodable::decode(this)
 716             }).unwrap();
 717             Ok((adjustment, this.read_struct_field("vtable_res", 1, |this| {
 718                 Ok(this.read_vtable_res(tcx, cdata))
 719             }).unwrap()))
 720         }).unwrap()
 721     }
 722
 723     fn read_vtable_res(&mut self,
 724                        tcx: &ty::ctxt<'tcx>,
 725                        cdata: &cstore::crate_metadata)
 726                        -> ty::vtable_res<'tcx>
 727     {
 728         self.read_vec_per_param_space(
 729             |this| this.read_vtable_param_res(tcx, cdata))
 730     }
 731
 732     fn read_vtable_param_res(&mut self,
 733                              tcx: &ty::ctxt<'tcx>, cdata: &cstore::crate_metadata)
 734                       -> ty::vtable_param_res<'tcx> {
 735         self.read_to_vec(|this| Ok(this.read_vtable_origin(tcx, cdata)))
 736              .unwrap().into_iter().collect()
 737     }
 738
 739     fn read_vtable_origin(&mut self,
 740                           tcx: &ty::ctxt<'tcx>, cdata: &cstore::crate_metadata)
 741         -> ty::vtable_origin<'tcx> {
 742         self.read_enum("vtable_origin", |this| {
 743             this.read_enum_variant(&["vtable_static",
 744                                      "vtable_param",
 745                                      "vtable_error",
 746                                      "vtable_closure"],
 747                                    |this, i| {
 748                 Ok(match i {
 749                   0 => {
 750                     ty::vtable_static(
 751                         this.read_enum_variant_arg(0, |this| {
 752                             Ok(this.read_def_id_nodcx(cdata))
 753                         }).unwrap(),
 754                         this.read_enum_variant_arg(1, |this| {
 755                             Ok(this.read_substs_nodcx(tcx, cdata))
 756                         }).unwrap(),
 757                         this.read_enum_variant_arg(2, |this| {
 758                             Ok(this.read_vtable_res(tcx, cdata))
 759                         }).unwrap()
 760                     )
 761                   }
 762                   1 => {
 763                     ty::vtable_param(
 764                         this.read_enum_variant_arg(0, |this| {
 765                             Decodable::decode(this)
 766                         }).unwrap(),
 767                         this.read_enum_variant_arg(1, |this| {
 768                             this.read_uint()
 769                         }).unwrap()
 770                     )
 771                   }
 772                   2 => {
 773                     ty::vtable_closure(
 774                         this.read_enum_variant_arg(0, |this| {
 775                             Ok(this.read_def_id_nodcx(cdata))
 776                         }).unwrap()
 777                     )
 778                   }
 779                   3 => {
 780                     ty::vtable_error
 781                   }
 782                   _ => panic!("bad enum variant")
 783                 })
 784             })
 785         }).unwrap()
 786     }
 787 }
 788
 789 // ___________________________________________________________________________
 790 //
 791
 792 fn encode_vec_per_param_space<T, F>(rbml_w: &mut Encoder,
 793                                     v: &subst::VecPerParamSpace<T>,
 794                                     mut f: F) where
 795     F: FnMut(&mut Encoder, &T),
 796 {
 797     for &space in &subst::ParamSpace::all() {
 798         rbml_w.emit_from_vec(v.get_slice(space),
 799                              |rbml_w, n| Ok(f(rbml_w, n))).unwrap();
 800     }
 801 }
 802
 803 // ______________________________________________________________________
 804 // Encoding and decoding the side tables
 805
 806 trait get_ty_str_ctxt<'tcx> {
 807     fn ty_str_ctxt<'a>(&'a self) -> tyencode::ctxt<'a, 'tcx>;
 808 }
 809
 810 impl<'a, 'tcx> get_ty_str_ctxt<'tcx> for e::EncodeContext<'a, 'tcx> {
 811     fn ty_str_ctxt<'b>(&'b self) -> tyencode::ctxt<'b, 'tcx> {
 812         tyencode::ctxt {
 813             diag: self.tcx.sess.diagnostic(),
 814             ds: e::def_to_string,
 815             tcx: self.tcx,
 816             abbrevs: &self.type_abbrevs
 817         }
 818     }
 819 }
 820
 821 trait rbml_writer_helpers<'tcx> {
 822     fn emit_closure_type<'a>(&mut self, ecx: &e::EncodeContext<'a, 'tcx>,
 823                              closure_type: &ty::ClosureTy<'tcx>);
 824     fn emit_method_origin<'a>(&mut self,
 825                               ecx: &e::EncodeContext<'a, 'tcx>,
 826                               method_origin: &ty::MethodOrigin<'tcx>);
 827     fn emit_ty<'a>(&mut self, ecx: &e::EncodeContext<'a, 'tcx>, ty: Ty<'tcx>);
 828     fn emit_tys<'a>(&mut self, ecx: &e::EncodeContext<'a, 'tcx>, tys: &[Ty<'tcx>]);
 829     fn emit_type_param_def<'a>(&mut self, ecx: &e::EncodeContext<'a, 'tcx>,
 830                                type_param_def: &ty::TypeParameterDef<'tcx>);
 831     fn emit_predicate<'a>(&mut self, ecx: &e::EncodeContext<'a, 'tcx>,
 832                           predicate: &ty::Predicate<'tcx>);
 833     fn emit_trait_ref<'a>(&mut self, ecx: &e::EncodeContext<'a, 'tcx>,
 834                           ty: &ty::TraitRef<'tcx>);
 835     fn emit_type_scheme<'a>(&mut self, ecx: &e::EncodeContext<'a, 'tcx>,
 836                             type_scheme: ty::TypeScheme<'tcx>);
 837     fn emit_substs<'a>(&mut self, ecx: &e::EncodeContext<'a, 'tcx>,
 838                        substs: &subst::Substs<'tcx>);
 839     fn emit_existential_bounds<'b>(&mut self, ecx: &e::EncodeContext<'b,'tcx>,
 840                                    bounds: &ty::ExistentialBounds<'tcx>);
 841     fn emit_builtin_bounds(&mut self, ecx: &e::EncodeContext, bounds: &ty::BuiltinBounds);
 842     fn emit_auto_adjustment<'a>(&mut self, ecx: &e::EncodeContext<'a, 'tcx>,
 843                                 adj: &ty::AutoAdjustment<'tcx>);
 844     fn emit_autoref<'a>(&mut self, ecx: &e::EncodeContext<'a, 'tcx>,
 845                         autoref: &ty::AutoRef<'tcx>);
 846     fn emit_auto_deref_ref<'a>(&mut self, ecx: &e::EncodeContext<'a, 'tcx>,
 847                                auto_deref_ref: &ty::AutoDerefRef<'tcx>);
 848     fn emit_unsize_kind<'a>(&mut self, ecx: &e::EncodeContext<'a, 'tcx>,
 849                             uk: &ty::UnsizeKind<'tcx>);
 850 }
 851
 852 impl<'a, 'tcx> rbml_writer_helpers<'tcx> for Encoder<'a> {
 853     fn emit_closure_type<'b>(&mut self,
 854                              ecx: &e::EncodeContext<'b, 'tcx>,
 855                              closure_type: &ty::ClosureTy<'tcx>) {
 856         self.emit_opaque(|this| {
 857             Ok(e::write_closure_type(ecx, this, closure_type))
 858         });
 859     }
 860
 861     fn emit_method_origin<'b>(&mut self,
 862                               ecx: &e::EncodeContext<'b, 'tcx>,
 863                               method_origin: &ty::MethodOrigin<'tcx>)
 864     {
 865         use serialize::Encoder;
 866
 867         self.emit_enum("MethodOrigin", |this| {
 868             match *method_origin {
 869                 ty::MethodStatic(def_id) => {
 870                     this.emit_enum_variant("MethodStatic", 0, 1, |this| {
 871                         Ok(this.emit_def_id(def_id))
 872                     })
 873                 }
 874
 875                 ty::MethodStaticClosure(def_id) => {
 876                     this.emit_enum_variant("MethodStaticClosure", 1, 1, |this| {
 877                         Ok(this.emit_def_id(def_id))
 878                     })
 879                 }
 880
 881                 ty::MethodTypeParam(ref p) => {
 882                     this.emit_enum_variant("MethodTypeParam", 2, 1, |this| {
 883                         this.emit_struct("MethodParam", 2, |this| {
 884                             try!(this.emit_struct_field("trait_ref", 0, |this| {
 885                                 Ok(this.emit_trait_ref(ecx, &*p.trait_ref))
 886                             }));
 887                             try!(this.emit_struct_field("method_num", 0, |this| {
 888                                 this.emit_uint(p.method_num)
 889                             }));
 890                             try!(this.emit_struct_field("impl_def_id", 0, |this| {
 891                                 this.emit_option(|this| {
 892                                     match p.impl_def_id {
 893                                         None => this.emit_option_none(),
 894                                         Some(did) => this.emit_option_some(|this| {
 895                                             Ok(this.emit_def_id(did))
 896                                         })
 897                                     }
 898                                 })
 899                             }));
 900                             Ok(())
 901                         })
 902                     })
 903                 }
 904
 905                 ty::MethodTraitObject(ref o) => {
 906                     this.emit_enum_variant("MethodTraitObject", 3, 1, |this| {
 907                         this.emit_struct("MethodObject", 2, |this| {
 908                             try!(this.emit_struct_field("trait_ref", 0, |this| {
 909                                 Ok(this.emit_trait_ref(ecx, &*o.trait_ref))
 910                             }));
 911                             try!(this.emit_struct_field("object_trait_id", 0, |this| {
 912                                 Ok(this.emit_def_id(o.object_trait_id))
 913                             }));
 914                             try!(this.emit_struct_field("method_num", 0, |this| {
 915                                 this.emit_uint(o.method_num)
 916                             }));
 917                             try!(this.emit_struct_field("vtable_index", 0, |this| {
 918                                 this.emit_uint(o.vtable_index)
 919                             }));
 920                             Ok(())
 921                         })
 922                     })
 923                 }
 924             }
 925         });
 926     }
 927
 928     fn emit_ty<'b>(&mut self, ecx: &e::EncodeContext<'b, 'tcx>, ty: Ty<'tcx>) {
 929         self.emit_opaque(|this| Ok(e::write_type(ecx, this, ty)));
 930     }
 931
 932     fn emit_tys<'b>(&mut self, ecx: &e::EncodeContext<'b, 'tcx>, tys: &[Ty<'tcx>]) {
 933         self.emit_from_vec(tys, |this, ty| Ok(this.emit_ty(ecx, *ty)));
 934     }
 935
 936     fn emit_trait_ref<'b>(&mut self, ecx: &e::EncodeContext<'b, 'tcx>,
 937                           trait_ref: &ty::TraitRef<'tcx>) {
 938         self.emit_opaque(|this| Ok(e::write_trait_ref(ecx, this, trait_ref)));
 939     }
 940
 941     fn emit_type_param_def<'b>(&mut self, ecx: &e::EncodeContext<'b, 'tcx>,
 942                                type_param_def: &ty::TypeParameterDef<'tcx>) {
 943         self.emit_opaque(|this| {
 944             Ok(tyencode::enc_type_param_def(this,
 945                                          &ecx.ty_str_ctxt(),
 946                                          type_param_def))
 947         });
 948     }
 949
 950     fn emit_predicate<'b>(&mut self, ecx: &e::EncodeContext<'b, 'tcx>,
 951                           predicate: &ty::Predicate<'tcx>) {
 952         self.emit_opaque(|this| {
 953             Ok(tyencode::enc_predicate(this,
 954                                        &ecx.ty_str_ctxt(),
 955                                        predicate))
 956         });
 957     }
 958
 959     fn emit_type_scheme<'b>(&mut self,
 960                             ecx: &e::EncodeContext<'b, 'tcx>,
 961                             type_scheme: ty::TypeScheme<'tcx>) {
 962         use serialize::Encoder;
 963
 964         self.emit_struct("TypeScheme", 2, |this| {
 965             this.emit_struct_field("generics", 0, |this| {
 966                 this.emit_struct("Generics", 2, |this| {
 967                     this.emit_struct_field("types", 0, |this| {
 968                         Ok(encode_vec_per_param_space(
 969                             this, &type_scheme.generics.types,
 970                             |this, def| this.emit_type_param_def(ecx, def)))
 971                     });
 972                     this.emit_struct_field("regions", 1, |this| {
 973                         Ok(encode_vec_per_param_space(
 974                             this, &type_scheme.generics.regions,
 975                             |this, def| def.encode(this).unwrap()))
 976                     })
 977                 })
 978             });
 979             this.emit_struct_field("ty", 1, |this| {
 980                 Ok(this.emit_ty(ecx, type_scheme.ty))
 981             })
 982         });
 983     }
 984
 985     fn emit_existential_bounds<'b>(&mut self, ecx: &e::EncodeContext<'b,'tcx>,
 986                                    bounds: &ty::ExistentialBounds<'tcx>) {
 987         self.emit_opaque(|this| Ok(tyencode::enc_existential_bounds(this,
 988                                                                     &ecx.ty_str_ctxt(),
 989                                                                     bounds)));
 990     }
 991
 992     fn emit_builtin_bounds(&mut self, ecx: &e::EncodeContext, bounds: &ty::BuiltinBounds) {
 993         self.emit_opaque(|this| Ok(tyencode::enc_builtin_bounds(this,
 994                                                                 &ecx.ty_str_ctxt(),
 995                                                                 bounds)));
 996     }
 997
 998     fn emit_substs<'b>(&mut self, ecx: &e::EncodeContext<'b, 'tcx>,
 999                        substs: &subst::Substs<'tcx>) {
1000         self.emit_opaque(|this| Ok(tyencode::enc_substs(this,
1001                                                            &ecx.ty_str_ctxt(),
1002                                                            substs)));
1003     }
1004
1005     fn emit_auto_adjustment<'b>(&mut self, ecx: &e::EncodeContext<'b, 'tcx>,
1006                                 adj: &ty::AutoAdjustment<'tcx>) {
1007         use serialize::Encoder;
1008
1009         self.emit_enum("AutoAdjustment", |this| {
1010             match *adj {
1011                 ty::AdjustReifyFnPointer(def_id) => {
1012                     this.emit_enum_variant("AdjustReifyFnPointer", 1, 2, |this| {
1013                         this.emit_enum_variant_arg(0, |this| def_id.encode(this))
1014                     })
1015                 }
1016
1017                 ty::AdjustUnsafeFnPointer => {
1018                     this.emit_enum_variant("AdjustUnsafeFnPointer", 2, 0, |_| {
1019                         Ok(())
1020                     })
1021                 }
1022
1023                 ty::AdjustDerefRef(ref auto_deref_ref) => {
1024                     this.emit_enum_variant("AdjustDerefRef", 3, 2, |this| {
1025                         this.emit_enum_variant_arg(0,
1026                             |this| Ok(this.emit_auto_deref_ref(ecx, auto_deref_ref)))
1027                     })
1028                 }
1029             }
1030         });
1031     }
1032
1033     fn emit_autoref<'b>(&mut self, ecx: &e::EncodeContext<'b, 'tcx>,
1034                         autoref: &ty::AutoRef<'tcx>) {
1035         use serialize::Encoder;
1036
1037         self.emit_enum("AutoRef", |this| {
1038             match autoref {
1039                 &ty::AutoPtr(r, m, None) => {
1040                     this.emit_enum_variant("AutoPtr", 0, 3, |this| {
1041                         this.emit_enum_variant_arg(0, |this| r.encode(this));
1042                         this.emit_enum_variant_arg(1, |this| m.encode(this));
1043                         this.emit_enum_variant_arg(2,
1044                             |this| this.emit_option(|this| this.emit_option_none()))
1045                     })
1046                 }
1047                 &ty::AutoPtr(r, m, Some(box ref a)) => {
1048                     this.emit_enum_variant("AutoPtr", 0, 3, |this| {
1049                         this.emit_enum_variant_arg(0, |this| r.encode(this));
1050                         this.emit_enum_variant_arg(1, |this| m.encode(this));
1051                         this.emit_enum_variant_arg(2, |this| this.emit_option(
1052                             |this| this.emit_option_some(|this| Ok(this.emit_autoref(ecx, a)))))
1053                     })
1054                 }
1055                 &ty::AutoUnsize(ref uk) => {
1056                     this.emit_enum_variant("AutoUnsize", 1, 1, |this| {
1057                         this.emit_enum_variant_arg(0, |this| Ok(this.emit_unsize_kind(ecx, uk)))
1058                     })
1059                 }
1060                 &ty::AutoUnsizeUniq(ref uk) => {
1061                     this.emit_enum_variant("AutoUnsizeUniq", 2, 1, |this| {
1062                         this.emit_enum_variant_arg(0, |this| Ok(this.emit_unsize_kind(ecx, uk)))
1063                     })
1064                 }
1065                 &ty::AutoUnsafe(m, None) => {
1066                     this.emit_enum_variant("AutoUnsafe", 3, 2, |this| {
1067                         this.emit_enum_variant_arg(0, |this| m.encode(this));
1068                         this.emit_enum_variant_arg(1,
1069                             |this| this.emit_option(|this| this.emit_option_none()))
1070                     })
1071                 }
1072                 &ty::AutoUnsafe(m, Some(box ref a)) => {
1073                     this.emit_enum_variant("AutoUnsafe", 3, 2, |this| {
1074                         this.emit_enum_variant_arg(0, |this| m.encode(this));
1075                         this.emit_enum_variant_arg(1, |this| this.emit_option(
1076                             |this| this.emit_option_some(|this| Ok(this.emit_autoref(ecx, a)))))
1077                     })
1078                 }
1079             }
1080         });
1081     }
1082
1083     fn emit_auto_deref_ref<'b>(&mut self, ecx: &e::EncodeContext<'b, 'tcx>,
1084                                auto_deref_ref: &ty::AutoDerefRef<'tcx>) {
1085         use serialize::Encoder;
1086
1087         self.emit_struct("AutoDerefRef", 2, |this| {
1088             this.emit_struct_field("autoderefs", 0, |this| auto_deref_ref.autoderefs.encode(this));
1089             this.emit_struct_field("autoref", 1, |this| {
1090                 this.emit_option(|this| {
1091                     match auto_deref_ref.autoref {
1092                         None => this.emit_option_none(),
1093                         Some(ref a) => this.emit_option_some(|this| Ok(this.emit_autoref(ecx, a))),
1094                     }
1095                 })
1096             })
1097         });
1098     }
1099
1100     fn emit_unsize_kind<'b>(&mut self, ecx: &e::EncodeContext<'b, 'tcx>,
1101                             uk: &ty::UnsizeKind<'tcx>) {
1102         use serialize::Encoder;
1103
1104         self.emit_enum("UnsizeKind", |this| {
1105             match *uk {
1106                 ty::UnsizeLength(len) => {
1107                     this.emit_enum_variant("UnsizeLength", 0, 1, |this| {
1108                         this.emit_enum_variant_arg(0, |this| len.encode(this))
1109                     })
1110                 }
1111                 ty::UnsizeStruct(box ref uk, idx) => {
1112                     this.emit_enum_variant("UnsizeStruct", 1, 2, |this| {
1113                         this.emit_enum_variant_arg(0, |this| Ok(this.emit_unsize_kind(ecx, uk)));
1114                         this.emit_enum_variant_arg(1, |this| idx.encode(this))
1115                     })
1116                 }
1117                 ty::UnsizeVtable(ty::TyTrait { ref principal,
1118                                                bounds: ref b },
1119                                  self_ty) => {
1120                     this.emit_enum_variant("UnsizeVtable", 2, 4, |this| {
1121                         this.emit_enum_variant_arg(0, |this| {
1122                             try!(this.emit_struct_field("principal", 0, |this| {
1123                                 Ok(this.emit_trait_ref(ecx, &*principal.0))
1124                             }));
1125                             this.emit_struct_field("bounds", 1, |this| {
1126                                 Ok(this.emit_existential_bounds(ecx, b))
1127                             })
1128                         });
1129                         this.emit_enum_variant_arg(1, |this| Ok(this.emit_ty(ecx, self_ty)))
1130                     })
1131                 }
1132                 ty::UnsizeUpcast(target_ty) => {
1133                     this.emit_enum_variant("UnsizeUpcast", 3, 1, |this| {
1134                         this.emit_enum_variant_arg(0, |this| Ok(this.emit_ty(ecx, target_ty)))
1135                     })
1136                 }
1137             }
1138         });
1139     }
1140 }
1141
1142 trait write_tag_and_id {
1143     fn tag<F>(&mut self, tag_id: c::astencode_tag, f: F) where F: FnOnce(&mut Self);
1144     fn id(&mut self, id: ast::NodeId);
1145 }
1146
1147 impl<'a> write_tag_and_id for Encoder<'a> {
1148     fn tag<F>(&mut self,
1149               tag_id: c::astencode_tag,
1150               f: F) where
1151         F: FnOnce(&mut Encoder<'a>),
1152     {
1153         self.start_tag(tag_id as uint);
1154         f(self);
1155         self.end_tag();
1156     }
1157
1158     fn id(&mut self, id: ast::NodeId) {
1159         id.encode(self).unwrap();
1160     }
1161 }
1162
1163 struct SideTableEncodingIdVisitor<'a, 'b:'a, 'c:'a, 'tcx:'c> {
1164     ecx: &'a e::EncodeContext<'c, 'tcx>,
1165     rbml_w: &'a mut Encoder<'b>,
1166 }
1167
1168 impl<'a, 'b, 'c, 'tcx> ast_util::IdVisitingOperation for
1169         SideTableEncodingIdVisitor<'a, 'b, 'c, 'tcx> {
1170     fn visit_id(&mut self, id: ast::NodeId) {
1171         encode_side_tables_for_id(self.ecx, self.rbml_w, id)
1172     }
1173 }
1174
1175 fn encode_side_tables_for_ii(ecx: &e::EncodeContext,
1176                              rbml_w: &mut Encoder,
1177                              ii: &ast::InlinedItem) {
1178     rbml_w.start_tag(c::tag_table as uint);
1179     ast_util::visit_ids_for_inlined_item(ii, &mut SideTableEncodingIdVisitor {
1180         ecx: ecx,
1181         rbml_w: rbml_w
1182     });
1183     rbml_w.end_tag();
1184 }
1185
1186 fn encode_side_tables_for_id(ecx: &e::EncodeContext,
1187                              rbml_w: &mut Encoder,
1188                              id: ast::NodeId) {
1189     let tcx = ecx.tcx;
1190
1191     debug!("Encoding side tables for id {}", id);
1192
1193     if let Some(def) = tcx.def_map.borrow().get(&id).map(|d| d.full_def()) {
1194         rbml_w.tag(c::tag_table_def, |rbml_w| {
1195             rbml_w.id(id);
1196             def.encode(rbml_w).unwrap();
1197         })
1198     }
1199
1200     if let Some(ty) = tcx.node_types.borrow().get(&id) {
1201         rbml_w.tag(c::tag_table_node_type, |rbml_w| {
1202             rbml_w.id(id);
1203             rbml_w.emit_ty(ecx, *ty);
1204         })
1205     }
1206
1207     if let Some(item_substs) = tcx.item_substs.borrow().get(&id) {
1208         rbml_w.tag(c::tag_table_item_subst, |rbml_w| {
1209             rbml_w.id(id);
1210             rbml_w.emit_substs(ecx, &item_substs.substs);
1211         })
1212     }
1213
1214     if let Some(fv) = tcx.freevars.borrow().get(&id) {
1215         rbml_w.tag(c::tag_table_freevars, |rbml_w| {
1216             rbml_w.id(id);
1217             rbml_w.emit_from_vec(fv, |rbml_w, fv_entry| {
1218                 Ok(encode_freevar_entry(rbml_w, fv_entry))
1219             });
1220         });
1221
1222         for freevar in fv {
1223             rbml_w.tag(c::tag_table_upvar_capture_map, |rbml_w| {
1224                 rbml_w.id(id);
1225
1226                 let var_id = freevar.def.def_id().node;
1227                 let upvar_id = ty::UpvarId {
1228                     var_id: var_id,
1229                     closure_expr_id: id
1230                 };
1231                 let upvar_capture = tcx.upvar_capture_map.borrow()[upvar_id].clone();
1232                 var_id.encode(rbml_w);
1233                 upvar_capture.encode(rbml_w);
1234             })
1235         }
1236     }
1237
1238     let lid = ast::DefId { krate: ast::LOCAL_CRATE, node: id };
1239     if let Some(type_scheme) = tcx.tcache.borrow().get(&lid) {
1240         rbml_w.tag(c::tag_table_tcache, |rbml_w| {
1241             rbml_w.id(id);
1242             rbml_w.emit_type_scheme(ecx, type_scheme.clone());
1243         })
1244     }
1245
1246     if let Some(type_param_def) = tcx.ty_param_defs.borrow().get(&id) {
1247         rbml_w.tag(c::tag_table_param_defs, |rbml_w| {
1248             rbml_w.id(id);
1249             rbml_w.emit_type_param_def(ecx, type_param_def)
1250         })
1251     }
1252
1253     let method_call = MethodCall::expr(id);
1254     if let Some(method) = tcx.method_map.borrow().get(&method_call) {
1255         rbml_w.tag(c::tag_table_method_map, |rbml_w| {
1256             rbml_w.id(id);
1257             encode_method_callee(ecx, rbml_w, method_call.adjustment, method)
1258         })
1259     }
1260
1261     if let Some(trait_ref) = tcx.object_cast_map.borrow().get(&id) {
1262         rbml_w.tag(c::tag_table_object_cast_map, |rbml_w| {
1263             rbml_w.id(id);
1264             rbml_w.emit_trait_ref(ecx, &*trait_ref.0);
1265         })
1266     }
1267
1268     if let Some(adjustment) = tcx.adjustments.borrow().get(&id) {
1269         match *adjustment {
1270             _ if ty::adjust_is_object(adjustment) => {
1271                 let method_call = MethodCall::autoobject(id);
1272                 if let Some(method) = tcx.method_map.borrow().get(&method_call) {
1273                     rbml_w.tag(c::tag_table_method_map, |rbml_w| {
1274                         rbml_w.id(id);
1275                         encode_method_callee(ecx, rbml_w, method_call.adjustment, method)
1276                     })
1277                 }
1278             }
1279             ty::AdjustDerefRef(ref adj) => {
1280                 assert!(!ty::adjust_is_object(adjustment));
1281                 for autoderef in 0..adj.autoderefs {
1282                     let method_call = MethodCall::autoderef(id, autoderef);
1283                     if let Some(method) = tcx.method_map.borrow().get(&method_call) {
1284                         rbml_w.tag(c::tag_table_method_map, |rbml_w| {
1285                             rbml_w.id(id);
1286                             encode_method_callee(ecx, rbml_w,
1287                                                  method_call.adjustment, method)
1288                         })
1289                     }
1290                 }
1291             }
1292             _ => {
1293                 assert!(!ty::adjust_is_object(adjustment));
1294             }
1295         }
1296
1297         rbml_w.tag(c::tag_table_adjustments, |rbml_w| {
1298             rbml_w.id(id);
1299             rbml_w.emit_auto_adjustment(ecx, adjustment);
1300         })
1301     }
1302
1303     if let Some(closure_type) = tcx.closure_tys.borrow().get(&ast_util::local_def(id)) {
1304         rbml_w.tag(c::tag_table_closure_tys, |rbml_w| {
1305             rbml_w.id(id);
1306             rbml_w.emit_closure_type(ecx, closure_type);
1307         })
1308     }
1309
1310     if let Some(closure_kind) = tcx.closure_kinds.borrow().get(&ast_util::local_def(id)) {
1311         rbml_w.tag(c::tag_table_closure_kinds, |rbml_w| {
1312             rbml_w.id(id);
1313             encode_closure_kind(rbml_w, *closure_kind)
1314         })
1315     }
1316
1317     for &qualif in tcx.const_qualif_map.borrow().get(&id).iter() {
1318         rbml_w.tag(c::tag_table_const_qualif, |rbml_w| {
1319             rbml_w.id(id);
1320             qualif.encode(rbml_w).unwrap()
1321         })
1322     }
1323 }
1324
1325 trait doc_decoder_helpers {
1326     fn as_int(&self) -> int;
1327     fn opt_child(&self, tag: c::astencode_tag) -> Option<Self>;
1328 }
1329
1330 impl<'a> doc_decoder_helpers for rbml::Doc<'a> {
1331     fn as_int(&self) -> int { reader::doc_as_u64(*self) as int }
1332     fn opt_child(&self, tag: c::astencode_tag) -> Option<rbml::Doc<'a>> {
1333         reader::maybe_get_doc(*self, tag as uint)
1334     }
1335 }
1336
1337 trait rbml_decoder_decoder_helpers<'tcx> {
1338     fn read_method_origin<'a, 'b>(&mut self, dcx: &DecodeContext<'a, 'b, 'tcx>)
1339                                   -> ty::MethodOrigin<'tcx>;
1340     fn read_ty<'a, 'b>(&mut self, dcx: &DecodeContext<'a, 'b, 'tcx>) -> Ty<'tcx>;
1341     fn read_tys<'a, 'b>(&mut self, dcx: &DecodeContext<'a, 'b, 'tcx>) -> Vec<Ty<'tcx>>;
1342     fn read_trait_ref<'a, 'b>(&mut self, dcx: &DecodeContext<'a, 'b, 'tcx>)
1343                               -> Rc<ty::TraitRef<'tcx>>;
1344     fn read_poly_trait_ref<'a, 'b>(&mut self, dcx: &DecodeContext<'a, 'b, 'tcx>)
1345                                    -> ty::PolyTraitRef<'tcx>;
1346     fn read_type_param_def<'a, 'b>(&mut self, dcx: &DecodeContext<'a, 'b, 'tcx>)
1347                                    -> ty::TypeParameterDef<'tcx>;
1348     fn read_predicate<'a, 'b>(&mut self, dcx: &DecodeContext<'a, 'b, 'tcx>)
1349                               -> ty::Predicate<'tcx>;
1350     fn read_type_scheme<'a, 'b>(&mut self, dcx: &DecodeContext<'a, 'b, 'tcx>)
1351                                 -> ty::TypeScheme<'tcx>;
1352     fn read_existential_bounds<'a, 'b>(&mut self, dcx: &DecodeContext<'a, 'b, 'tcx>)
1353                                        -> ty::ExistentialBounds<'tcx>;
1354     fn read_substs<'a, 'b>(&mut self, dcx: &DecodeContext<'a, 'b, 'tcx>)
1355                            -> subst::Substs<'tcx>;
1356     fn read_auto_adjustment<'a, 'b>(&mut self, dcx: &DecodeContext<'a, 'b, 'tcx>)
1357                                     -> ty::AutoAdjustment<'tcx>;
1358     fn read_closure_kind<'a, 'b>(&mut self, dcx: &DecodeContext<'a, 'b, 'tcx>)
1359                                  -> ty::ClosureKind;
1360     fn read_closure_ty<'a, 'b>(&mut self, dcx: &DecodeContext<'a, 'b, 'tcx>)
1361                                -> ty::ClosureTy<'tcx>;
1362     fn read_auto_deref_ref<'a, 'b>(&mut self, dcx: &DecodeContext<'a, 'b, 'tcx>)
1363                                    -> ty::AutoDerefRef<'tcx>;
1364     fn read_autoref<'a, 'b>(&mut self, dcx: &DecodeContext<'a, 'b, 'tcx>)
1365                             -> ty::AutoRef<'tcx>;
1366     fn read_unsize_kind<'a, 'b>(&mut self, dcx: &DecodeContext<'a, 'b, 'tcx>)
1367                                 -> ty::UnsizeKind<'tcx>;
1368     fn convert_def_id(&mut self,
1369                       dcx: &DecodeContext,
1370                       source: DefIdSource,
1371                       did: ast::DefId)
1372                       -> ast::DefId;
1373
1374     // Versions of the type reading functions that don't need the full
1375     // DecodeContext.
1376     fn read_ty_nodcx(&mut self,
1377                      tcx: &ty::ctxt<'tcx>, cdata: &cstore::crate_metadata) -> Ty<'tcx>;
1378     fn read_tys_nodcx(&mut self,
1379                       tcx: &ty::ctxt<'tcx>,
1380                       cdata: &cstore::crate_metadata) -> Vec<Ty<'tcx>>;
1381     fn read_substs_nodcx(&mut self, tcx: &ty::ctxt<'tcx>,
1382                          cdata: &cstore::crate_metadata)
1383                          -> subst::Substs<'tcx>;
1384 }
1385
1386 impl<'a, 'tcx> rbml_decoder_decoder_helpers<'tcx> for reader::Decoder<'a> {
1387     fn read_ty_nodcx(&mut self,
1388                      tcx: &ty::ctxt<'tcx>, cdata: &cstore::crate_metadata) -> Ty<'tcx> {
1389         self.read_opaque(|_, doc| {
1390             Ok(tydecode::parse_ty_data(
1391                 doc.data,
1392                 cdata.cnum,
1393                 doc.start,
1394                 tcx,
1395                 |_, id| decoder::translate_def_id(cdata, id)))
1396         }).unwrap()
1397     }
1398
1399     fn read_tys_nodcx(&mut self,
1400                       tcx: &ty::ctxt<'tcx>,
1401                       cdata: &cstore::crate_metadata) -> Vec<Ty<'tcx>> {
1402         self.read_to_vec(|this| Ok(this.read_ty_nodcx(tcx, cdata)) )
1403             .unwrap()
1404             .into_iter()
1405             .collect()
1406     }
1407
1408     fn read_substs_nodcx(&mut self,
1409                          tcx: &ty::ctxt<'tcx>,
1410                          cdata: &cstore::crate_metadata)
1411                          -> subst::Substs<'tcx>
1412     {
1413         self.read_opaque(|_, doc| {
1414             Ok(tydecode::parse_substs_data(
1415                 doc.data,
1416                 cdata.cnum,
1417                 doc.start,
1418                 tcx,
1419                 |_, id| decoder::translate_def_id(cdata, id)))
1420         }).unwrap()
1421     }
1422
1423     fn read_method_origin<'b, 'c>(&mut self, dcx: &DecodeContext<'b, 'c, 'tcx>)
1424                                   -> ty::MethodOrigin<'tcx>
1425     {
1426         self.read_enum("MethodOrigin", |this| {
1427             let variants = &["MethodStatic", "MethodStaticClosure",
1428                              "MethodTypeParam", "MethodTraitObject"];
1429             this.read_enum_variant(variants, |this, i| {
1430                 Ok(match i {
1431                     0 => {
1432                         let def_id = this.read_def_id(dcx);
1433                         ty::MethodStatic(def_id)
1434                     }
1435
1436                     1 => {
1437                         let def_id = this.read_def_id(dcx);
1438                         ty::MethodStaticClosure(def_id)
1439                     }
1440
1441                     2 => {
1442                         this.read_struct("MethodTypeParam", 2, |this| {
1443                             Ok(ty::MethodTypeParam(
1444                                 ty::MethodParam {
1445                                     trait_ref: {
1446                                         this.read_struct_field("trait_ref", 0, |this| {
1447                                             Ok(this.read_trait_ref(dcx))
1448                                         }).unwrap()
1449                                     },
1450                                     method_num: {
1451                                         this.read_struct_field("method_num", 1, |this| {
1452                                             this.read_uint()
1453                                         }).unwrap()
1454                                     },
1455                                     impl_def_id: {
1456                                         this.read_struct_field("impl_def_id", 2, |this| {
1457                                             this.read_option(|this, b| {
1458                                                 if b {
1459                                                     Ok(Some(this.read_def_id(dcx)))
1460                                                 } else {
1461                                                     Ok(None)
1462                                                 }
1463                                             })
1464                                         }).unwrap()
1465                                     }
1466                                 }))
1467                         }).unwrap()
1468                     }
1469
1470                     3 => {
1471                         this.read_struct("MethodTraitObject", 2, |this| {
1472                             Ok(ty::MethodTraitObject(
1473                                 ty::MethodObject {
1474                                     trait_ref: {
1475                                         this.read_struct_field("trait_ref", 0, |this| {
1476                                             Ok(this.read_trait_ref(dcx))
1477                                         }).unwrap()
1478                                     },
1479                                     object_trait_id: {
1480                                         this.read_struct_field("object_trait_id", 1, |this| {
1481                                             Ok(this.read_def_id(dcx))
1482                                         }).unwrap()
1483                                     },
1484                                     method_num: {
1485                                         this.read_struct_field("method_num", 2, |this| {
1486                                             this.read_uint()
1487                                         }).unwrap()
1488                                     },
1489                                     vtable_index: {
1490                                         this.read_struct_field("vtable_index", 3, |this| {
1491                                             this.read_uint()
1492                                         }).unwrap()
1493                                     },
1494                                 }))
1495                         }).unwrap()
1496                     }
1497
1498                     _ => panic!("..")
1499                 })
1500             })
1501         }).unwrap()
1502     }
1503
1504
1505     fn read_ty<'b, 'c>(&mut self, dcx: &DecodeContext<'b, 'c, 'tcx>) -> Ty<'tcx> {
1506         // Note: regions types embed local node ids.  In principle, we
1507         // should translate these node ids into the new decode
1508         // context.  However, we do not bother, because region types
1509         // are not used during trans.
1510
1511         return self.read_opaque(|this, doc| {
1512             debug!("read_ty({})", type_string(doc));
1513
1514             let ty = tydecode::parse_ty_data(
1515                 doc.data,
1516                 dcx.cdata.cnum,
1517                 doc.start,
1518                 dcx.tcx,
1519                 |s, a| this.convert_def_id(dcx, s, a));
1520
1521             Ok(ty)
1522         }).unwrap();
1523
1524         fn type_string(doc: rbml::Doc) -> String {
1525             let mut str = String::new();
1526             for i in doc.start..doc.end {
1527                 str.push(doc.data[i] as char);
1528             }
1529             str
1530         }
1531     }
1532
1533     fn read_tys<'b, 'c>(&mut self, dcx: &DecodeContext<'b, 'c, 'tcx>)
1534                         -> Vec<Ty<'tcx>> {
1535         self.read_to_vec(|this| Ok(this.read_ty(dcx))).unwrap().into_iter().collect()
1536     }
1537
1538     fn read_trait_ref<'b, 'c>(&mut self, dcx: &DecodeContext<'b, 'c, 'tcx>)
1539                               -> Rc<ty::TraitRef<'tcx>> {
1540         self.read_opaque(|this, doc| {
1541             let ty = tydecode::parse_trait_ref_data(
1542                 doc.data,
1543                 dcx.cdata.cnum,
1544                 doc.start,
1545                 dcx.tcx,
1546                 |s, a| this.convert_def_id(dcx, s, a));
1547             Ok(ty)
1548         }).unwrap()
1549     }
1550
1551     fn read_poly_trait_ref<'b, 'c>(&mut self, dcx: &DecodeContext<'b, 'c, 'tcx>)
1552                                    -> ty::PolyTraitRef<'tcx> {
1553         ty::Binder(self.read_opaque(|this, doc| {
1554             let ty = tydecode::parse_trait_ref_data(
1555                 doc.data,
1556                 dcx.cdata.cnum,
1557                 doc.start,
1558                 dcx.tcx,
1559                 |s, a| this.convert_def_id(dcx, s, a));
1560             Ok(ty)
1561         }).unwrap())
1562     }
1563
1564     fn read_type_param_def<'b, 'c>(&mut self, dcx: &DecodeContext<'b, 'c, 'tcx>)
1565                                    -> ty::TypeParameterDef<'tcx> {
1566         self.read_opaque(|this, doc| {
1567             Ok(tydecode::parse_type_param_def_data(
1568                 doc.data,
1569                 doc.start,
1570                 dcx.cdata.cnum,
1571                 dcx.tcx,
1572                 |s, a| this.convert_def_id(dcx, s, a)))
1573         }).unwrap()
1574     }
1575
1576     fn read_predicate<'b, 'c>(&mut self, dcx: &DecodeContext<'b, 'c, 'tcx>)
1577                               -> ty::Predicate<'tcx>
1578     {
1579         self.read_opaque(|this, doc| {
1580             Ok(tydecode::parse_predicate_data(doc.data, doc.start, dcx.cdata.cnum, dcx.tcx,
1581                                               |s, a| this.convert_def_id(dcx, s, a)))
1582         }).unwrap()
1583     }
1584
1585     fn read_type_scheme<'b, 'c>(&mut self, dcx: &DecodeContext<'b, 'c, 'tcx>)
1586                                 -> ty::TypeScheme<'tcx> {
1587         self.read_struct("TypeScheme", 3, |this| {
1588             Ok(ty::TypeScheme {
1589                 generics: this.read_struct_field("generics", 0, |this| {
1590                     this.read_struct("Generics", 2, |this| {
1591                         Ok(ty::Generics {
1592                             types:
1593                             this.read_struct_field("types", 0, |this| {
1594                                 Ok(this.read_vec_per_param_space(
1595                                     |this| this.read_type_param_def(dcx)))
1596                             }).unwrap(),
1597
1598                             regions:
1599                             this.read_struct_field("regions", 1, |this| {
1600                                 Ok(this.read_vec_per_param_space(
1601                                     |this| Decodable::decode(this).unwrap()))
1602                             }).unwrap(),
1603                         })
1604                     })
1605                 }).unwrap(),
1606                 ty: this.read_struct_field("ty", 1, |this| {
1607                     Ok(this.read_ty(dcx))
1608                 }).unwrap()
1609             })
1610         }).unwrap()
1611     }
1612
1613     fn read_existential_bounds<'b, 'c>(&mut self, dcx: &DecodeContext<'b, 'c, 'tcx>)
1614                                        -> ty::ExistentialBounds<'tcx>
1615     {
1616         self.read_opaque(|this, doc| {
1617             Ok(tydecode::parse_existential_bounds_data(doc.data,
1618                                                        dcx.cdata.cnum,
1619                                                        doc.start,
1620                                                        dcx.tcx,
1621                                                        |s, a| this.convert_def_id(dcx, s, a)))
1622         }).unwrap()
1623     }
1624
1625     fn read_substs<'b, 'c>(&mut self, dcx: &DecodeContext<'b, 'c, 'tcx>)
1626                            -> subst::Substs<'tcx> {
1627         self.read_opaque(|this, doc| {
1628             Ok(tydecode::parse_substs_data(doc.data,
1629                                         dcx.cdata.cnum,
1630                                         doc.start,
1631                                         dcx.tcx,
1632                                         |s, a| this.convert_def_id(dcx, s, a)))
1633         }).unwrap()
1634     }
1635
1636     fn read_auto_adjustment<'b, 'c>(&mut self, dcx: &DecodeContext<'b, 'c, 'tcx>)
1637                                     -> ty::AutoAdjustment<'tcx> {
1638         self.read_enum("AutoAdjustment", |this| {
1639             let variants = ["AutoAddEnv", "AutoDerefRef"];
1640             this.read_enum_variant(&variants, |this, i| {
1641                 Ok(match i {
1642                     1 => {
1643                         let def_id: ast::DefId =
1644                             this.read_def_id(dcx);
1645
1646                         ty::AdjustReifyFnPointer(def_id)
1647                     }
1648                     2 => {
1649                         ty::AdjustUnsafeFnPointer
1650                     }
1651                     3 => {
1652                         let auto_deref_ref: ty::AutoDerefRef =
1653                             this.read_enum_variant_arg(0,
1654                                 |this| Ok(this.read_auto_deref_ref(dcx))).unwrap();
1655
1656                         ty::AdjustDerefRef(auto_deref_ref)
1657                     }
1658                     _ => panic!("bad enum variant for ty::AutoAdjustment")
1659                 })
1660             })
1661         }).unwrap()
1662     }
1663
1664     fn read_auto_deref_ref<'b, 'c>(&mut self, dcx: &DecodeContext<'b, 'c, 'tcx>)
1665                                    -> ty::AutoDerefRef<'tcx> {
1666         self.read_struct("AutoDerefRef", 2, |this| {
1667             Ok(ty::AutoDerefRef {
1668                 autoderefs: this.read_struct_field("autoderefs", 0, |this| {
1669                     Decodable::decode(this)
1670                 }).unwrap(),
1671                 autoref: this.read_struct_field("autoref", 1, |this| {
1672                     this.read_option(|this, b| {
1673                         if b {
1674                             Ok(Some(this.read_autoref(dcx)))
1675                         } else {
1676                             Ok(None)
1677                         }
1678                     })
1679                 }).unwrap(),
1680             })
1681         }).unwrap()
1682     }
1683
1684     fn read_autoref<'b, 'c>(&mut self, dcx: &DecodeContext<'b, 'c, 'tcx>) -> ty::AutoRef<'tcx> {
1685         self.read_enum("AutoRef", |this| {
1686             let variants = ["AutoPtr",
1687                             "AutoUnsize",
1688                             "AutoUnsizeUniq",
1689                             "AutoUnsafe"];
1690             this.read_enum_variant(&variants, |this, i| {
1691                 Ok(match i {
1692                     0 => {
1693                         let r: ty::Region =
1694                             this.read_enum_variant_arg(0, |this| Decodable::decode(this)).unwrap();
1695                         let m: ast::Mutability =
1696                             this.read_enum_variant_arg(1, |this| Decodable::decode(this)).unwrap();
1697                         let a: Option<Box<ty::AutoRef>> =
1698                             this.read_enum_variant_arg(2, |this| this.read_option(|this, b| {
1699                                 if b {
1700                                     Ok(Some(box this.read_autoref(dcx)))
1701                                 } else {
1702                                     Ok(None)
1703                                 }
1704                             })).unwrap();
1705
1706                         ty::AutoPtr(r.tr(dcx), m, a)
1707                     }
1708                     1 => {
1709                         let uk: ty::UnsizeKind =
1710                             this.read_enum_variant_arg(0,
1711                                 |this| Ok(this.read_unsize_kind(dcx))).unwrap();
1712
1713                         ty::AutoUnsize(uk)
1714                     }
1715                     2 => {
1716                         let uk: ty::UnsizeKind =
1717                             this.read_enum_variant_arg(0,
1718                                 |this| Ok(this.read_unsize_kind(dcx))).unwrap();
1719
1720                         ty::AutoUnsizeUniq(uk)
1721                     }
1722                     3 => {
1723                         let m: ast::Mutability =
1724                             this.read_enum_variant_arg(0, |this| Decodable::decode(this)).unwrap();
1725                         let a: Option<Box<ty::AutoRef>> =
1726                             this.read_enum_variant_arg(1, |this| this.read_option(|this, b| {
1727                                 if b {
1728                                     Ok(Some(box this.read_autoref(dcx)))
1729                                 } else {
1730                                     Ok(None)
1731                                 }
1732                             })).unwrap();
1733
1734                         ty::AutoUnsafe(m, a)
1735                     }
1736                     _ => panic!("bad enum variant for ty::AutoRef")
1737                 })
1738             })
1739         }).unwrap()
1740     }
1741
1742     fn read_unsize_kind<'b, 'c>(&mut self, dcx: &DecodeContext<'b, 'c, 'tcx>)
1743                                 -> ty::UnsizeKind<'tcx> {
1744         self.read_enum("UnsizeKind", |this| {
1745             let variants = &["UnsizeLength", "UnsizeStruct", "UnsizeVtable", "UnsizeUpcast"];
1746             this.read_enum_variant(variants, |this, i| {
1747                 Ok(match i {
1748                     0 => {
1749                         let len: uint =
1750                             this.read_enum_variant_arg(0, |this| Decodable::decode(this)).unwrap();
1751
1752                         ty::UnsizeLength(len)
1753                     }
1754                     1 => {
1755                         let uk: ty::UnsizeKind =
1756                             this.read_enum_variant_arg(0,
1757                                 |this| Ok(this.read_unsize_kind(dcx))).unwrap();
1758                         let idx: uint =
1759                             this.read_enum_variant_arg(1, |this| Decodable::decode(this)).unwrap();
1760
1761                         ty::UnsizeStruct(box uk, idx)
1762                     }
1763                     2 => {
1764                         let ty_trait = try!(this.read_enum_variant_arg(0, |this| {
1765                             let principal = try!(this.read_struct_field("principal", 0, |this| {
1766                                 Ok(this.read_poly_trait_ref(dcx))
1767                             }));
1768                             Ok(ty::TyTrait {
1769                                 principal: principal,
1770                                 bounds: try!(this.read_struct_field("bounds", 1, |this| {
1771                                     Ok(this.read_existential_bounds(dcx))
1772                                 })),
1773                             })
1774                         }));
1775                         let self_ty =
1776                             this.read_enum_variant_arg(1, |this| Ok(this.read_ty(dcx))).unwrap();
1777                         ty::UnsizeVtable(ty_trait, self_ty)
1778                     }
1779                     3 => {
1780                         let target_ty =
1781                             this.read_enum_variant_arg(0, |this| Ok(this.read_ty(dcx))).unwrap();
1782                         ty::UnsizeUpcast(target_ty)
1783                     }
1784                     _ => panic!("bad enum variant for ty::UnsizeKind")
1785                 })
1786             })
1787         }).unwrap()
1788     }
1789
1790     fn read_closure_kind<'b, 'c>(&mut self, _dcx: &DecodeContext<'b, 'c, 'tcx>)
1791                                  -> ty::ClosureKind
1792     {
1793         Decodable::decode(self).unwrap()
1794     }
1795
1796     fn read_closure_ty<'b, 'c>(&mut self, dcx: &DecodeContext<'b, 'c, 'tcx>)
1797                                -> ty::ClosureTy<'tcx>
1798     {
1799         self.read_opaque(|this, doc| {
1800             Ok(tydecode::parse_ty_closure_data(
1801                 doc.data,
1802                 dcx.cdata.cnum,
1803                 doc.start,
1804                 dcx.tcx,
1805                 |s, a| this.convert_def_id(dcx, s, a)))
1806         }).unwrap()
1807     }
1808
1809     /// Converts a def-id that appears in a type.  The correct
1810     /// translation will depend on what kind of def-id this is.
1811     /// This is a subtle point: type definitions are not
1812     /// inlined into the current crate, so if the def-id names
1813     /// a nominal type or type alias, then it should be
1814     /// translated to refer to the source crate.
1815     ///
1816     /// However, *type parameters* are cloned along with the function
1817     /// they are attached to.  So we should translate those def-ids
1818     /// to refer to the new, cloned copy of the type parameter.
1819     /// We only see references to free type parameters in the body of
1820     /// an inlined function. In such cases, we need the def-id to
1821     /// be a local id so that the TypeContents code is able to lookup
1822     /// the relevant info in the ty_param_defs table.
1823     ///
1824     /// *Region parameters*, unfortunately, are another kettle of fish.
1825     /// In such cases, def_id's can appear in types to distinguish
1826     /// shadowed bound regions and so forth. It doesn't actually
1827     /// matter so much what we do to these, since regions are erased
1828     /// at trans time, but it's good to keep them consistent just in
1829     /// case. We translate them with `tr_def_id()` which will map
1830     /// the crate numbers back to the original source crate.
1831     ///
1832     /// Unboxed closures are cloned along with the function being
1833     /// inlined, and all side tables use interned node IDs, so we
1834     /// translate their def IDs accordingly.
1835     ///
1836     /// It'd be really nice to refactor the type repr to not include
1837     /// def-ids so that all these distinctions were unnecessary.
1838     fn convert_def_id(&mut self,
1839                       dcx: &DecodeContext,
1840                       source: tydecode::DefIdSource,
1841                       did: ast::DefId)
1842                       -> ast::DefId {
1843         let r = match source {
1844             NominalType | TypeWithId | RegionParameter => dcx.tr_def_id(did),
1845             TypeParameter | ClosureSource => dcx.tr_intern_def_id(did)
1846         };
1847         debug!("convert_def_id(source={:?}, did={:?})={:?}", source, did, r);
1848         return r;
1849     }
1850 }
1851
1852 fn decode_side_tables(dcx: &DecodeContext,
1853                       ast_doc: rbml::Doc) {
1854     let tbl_doc = ast_doc.get(c::tag_table as uint);
1855     reader::docs(tbl_doc, |tag, entry_doc| {
1856         let mut entry_dsr = reader::Decoder::new(entry_doc);
1857         let id0: ast::NodeId = Decodable::decode(&mut entry_dsr).unwrap();
1858         let id = dcx.tr_id(id0);
1859
1860         debug!(">> Side table document with tag 0x{:x} \
1861                 found for id {} (orig {})",
1862                tag, id, id0);
1863         let decoded_tag: Option<c::astencode_tag> = FromPrimitive::from_usize(tag);
1864         match decoded_tag {
1865             None => {
1866                 dcx.tcx.sess.bug(
1867                     &format!("unknown tag found in side tables: {:x}",
1868                             tag));
1869             }
1870             Some(value) => {
1871                 let val_dsr = &mut entry_dsr;
1872
1873                 match value {
1874                     c::tag_table_def => {
1875                         let def = decode_def(dcx, val_dsr);
1876                         dcx.tcx.def_map.borrow_mut().insert(id, def::PathResolution {
1877                             base_def: def,
1878                             // This doesn't matter cross-crate.
1879                             last_private: LastMod(AllPublic),
1880                             depth: 0
1881                         });
1882                     }
1883                     c::tag_table_node_type => {
1884                         let ty = val_dsr.read_ty(dcx);
1885                         debug!("inserting ty for node {}: {}",
1886                                id, ty_to_string(dcx.tcx, ty));
1887                         dcx.tcx.node_types.borrow_mut().insert(id, ty);
1888                     }
1889                     c::tag_table_item_subst => {
1890                         let item_substs = ty::ItemSubsts {
1891                             substs: val_dsr.read_substs(dcx)
1892                         };
1893                         dcx.tcx.item_substs.borrow_mut().insert(
1894                             id, item_substs);
1895                     }
1896                     c::tag_table_freevars => {
1897                         let fv_info = val_dsr.read_to_vec(|val_dsr| {
1898                             Ok(val_dsr.read_freevar_entry(dcx))
1899                         }).unwrap().into_iter().collect();
1900                         dcx.tcx.freevars.borrow_mut().insert(id, fv_info);
1901                     }
1902                     c::tag_table_upvar_capture_map => {
1903                         let var_id: ast::NodeId = Decodable::decode(val_dsr).unwrap();
1904                         let upvar_id = ty::UpvarId {
1905                             var_id: dcx.tr_id(var_id),
1906                             closure_expr_id: id
1907                         };
1908                         let ub: ty::UpvarCapture = Decodable::decode(val_dsr).unwrap();
1909                         dcx.tcx.upvar_capture_map.borrow_mut().insert(upvar_id, ub.tr(dcx));
1910                     }
1911                     c::tag_table_tcache => {
1912                         let type_scheme = val_dsr.read_type_scheme(dcx);
1913                         let lid = ast::DefId { krate: ast::LOCAL_CRATE, node: id };
1914                         dcx.tcx.tcache.borrow_mut().insert(lid, type_scheme);
1915                     }
1916                     c::tag_table_param_defs => {
1917                         let bounds = val_dsr.read_type_param_def(dcx);
1918                         dcx.tcx.ty_param_defs.borrow_mut().insert(id, bounds);
1919                     }
1920                     c::tag_table_method_map => {
1921                         let (adjustment, method) = val_dsr.read_method_callee(dcx);
1922                         let method_call = MethodCall {
1923                             expr_id: id,
1924                             adjustment: adjustment
1925                         };
1926                         dcx.tcx.method_map.borrow_mut().insert(method_call, method);
1927                     }
1928                     c::tag_table_object_cast_map => {
1929                         let trait_ref = val_dsr.read_poly_trait_ref(dcx);
1930                         dcx.tcx.object_cast_map.borrow_mut()
1931                                                .insert(id, trait_ref);
1932                     }
1933                     c::tag_table_adjustments => {
1934                         let adj: ty::AutoAdjustment = val_dsr.read_auto_adjustment(dcx);
1935                         dcx.tcx.adjustments.borrow_mut().insert(id, adj);
1936                     }
1937                     c::tag_table_closure_tys => {
1938                         let closure_ty =
1939                             val_dsr.read_closure_ty(dcx);
1940                         dcx.tcx.closure_tys.borrow_mut().insert(ast_util::local_def(id),
1941                                                                 closure_ty);
1942                     }
1943                     c::tag_table_closure_kinds => {
1944                         let closure_kind =
1945                             val_dsr.read_closure_kind(dcx);
1946                         dcx.tcx.closure_kinds.borrow_mut().insert(ast_util::local_def(id),
1947                                                                   closure_kind);
1948                     }
1949                     c::tag_table_const_qualif => {
1950                         let qualif: ConstQualif = Decodable::decode(val_dsr).unwrap();
1951                         dcx.tcx.const_qualif_map.borrow_mut().insert(id, qualif);
1952                     }
1953                     _ => {
1954                         dcx.tcx.sess.bug(
1955                             &format!("unknown tag found in side tables: {:x}",
1956                                     tag));
1957                     }
1958                 }
1959             }
1960         }
1961
1962         debug!(">< Side table doc loaded");
1963         true
1964     });
1965 }
1966
1967 // ______________________________________________________________________
1968 // Testing of astencode_gen
1969
1970 #[cfg(test)]
1971 fn encode_item_ast(rbml_w: &mut Encoder, item: &ast::Item) {
1972     rbml_w.start_tag(c::tag_tree as uint);
1973     (*item).encode(rbml_w);
1974     rbml_w.end_tag();
1975 }
1976
1977 #[cfg(test)]
1978 fn decode_item_ast(par_doc: rbml::Doc) -> ast::Item {
1979     let chi_doc = par_doc.get(c::tag_tree as uint);
1980     let mut d = reader::Decoder::new(chi_doc);
1981     Decodable::decode(&mut d).unwrap()
1982 }
1983
1984 #[cfg(test)]
1985 trait fake_ext_ctxt {
1986     fn cfg(&self) -> ast::CrateConfig;
1987     fn parse_sess<'a>(&'a self) -> &'a parse::ParseSess;
1988     fn call_site(&self) -> Span;
1989     fn ident_of(&self, st: &str) -> ast::Ident;
1990 }
1991
1992 #[cfg(test)]
1993 impl fake_ext_ctxt for parse::ParseSess {
1994     fn cfg(&self) -> ast::CrateConfig {
1995         Vec::new()
1996     }
1997     fn parse_sess<'a>(&'a self) -> &'a parse::ParseSess { self }
1998     fn call_site(&self) -> Span {
1999         codemap::Span {
2000             lo: codemap::BytePos(0),
2001             hi: codemap::BytePos(0),
2002             expn_id: codemap::NO_EXPANSION
2003         }
2004     }
2005     fn ident_of(&self, st: &str) -> ast::Ident {
2006         token::str_to_ident(st)
2007     }
2008 }
2009
2010 #[cfg(test)]
2011 fn mk_ctxt() -> parse::ParseSess {
2012     parse::new_parse_sess()
2013 }
2014
2015 #[cfg(test)]
2016 fn roundtrip(in_item: Option<P<ast::Item>>) {
2017     let in_item = in_item.unwrap();
2018     let mut wr = Cursor::new(Vec::new());
2019     encode_item_ast(&mut Encoder::new(&mut wr), &*in_item);
2020     let rbml_doc = rbml::Doc::new(wr.get_ref());
2021     let out_item = decode_item_ast(rbml_doc);
2022
2023     assert!(*in_item == out_item);
2024 }
2025
2026 #[test]
2027 fn test_basic() {
2028     let cx = mk_ctxt();
2029     roundtrip(quote_item!(&cx,
2030         fn foo() {}
2031     ));
2032 }
2033 /* NOTE: When there's a snapshot, update this (yay quasiquoter!)
2034 #[test]
2035 fn test_smalltalk() {
2036     let cx = mk_ctxt();
2037     roundtrip(quote_item!(&cx,
2038         fn foo() -> int { 3 + 4 } // first smalltalk program ever executed.
2039     ));
2040 }
2041 */
2042
2043 #[test]
2044 fn test_more() {
2045     let cx = mk_ctxt();
2046     roundtrip(quote_item!(&cx,
2047         fn foo(x: uint, y: uint) -> uint {
2048             let z = x + y;
2049             return z;
2050         }
2051     ));
2052 }
2053
2054 #[test]
2055 fn test_simplification() {
2056     let cx = mk_ctxt();
2057     let item = quote_item!(&cx,
2058         fn new_int_alist<B>() -> alist<int, B> {
2059             fn eq_int(a: int, b: int) -> bool { a == b }
2060             return alist {eq_fn: eq_int, data: Vec::new()};
2061         }
2062     ).unwrap();
2063     let item_in = e::IIItemRef(&*item);
2064     let item_out = simplify_ast(item_in);
2065     let item_exp = ast::IIItem(quote_item!(&cx,
2066         fn new_int_alist<B>() -> alist<int, B> {
2067             return alist {eq_fn: eq_int, data: Vec::new()};
2068         }
2069     ).unwrap());
2070     match (item_out, item_exp) {
2071       (ast::IIItem(item_out), ast::IIItem(item_exp)) => {
2072         assert!(pprust::item_to_string(&*item_out) ==
2073                 pprust::item_to_string(&*item_exp));
2074       }
2075       _ => panic!()
2076     }
2077 }