src/librustc_metadata/schema.rs

   1 // Copyright 2012-2016 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 use index;
  12
  13 use rustc::hir;
  14 use rustc::hir::def::{self, CtorKind};
  15 use rustc::hir::def_id::{DefIndex, DefId, CrateNum};
  16 use rustc::ich::StableHashingContext;
  17 use rustc::middle::cstore::{DepKind, LinkagePreference, NativeLibrary, ForeignModule};
  18 use rustc::middle::lang_items;
  19 use rustc::mir;
  20 use rustc::session::CrateDisambiguator;
  21 use rustc::ty::{self, Ty, ReprOptions};
  22 use rustc_target::spec::{PanicStrategy, TargetTriple};
  23 use rustc_data_structures::svh::Svh;
  24
  25 use rustc_serialize as serialize;
  26 use syntax::{ast, attr};
  27 use syntax::edition::Edition;
  28 use syntax::symbol::Symbol;
  29 use syntax_pos::{self, Span};
  30
  31 use std::marker::PhantomData;
  32 use std::mem;
  33
  34 use rustc_data_structures::stable_hasher::{StableHasher, HashStable,
  35                                            StableHasherResult};
  36
  37 pub fn rustc_version() -> String {
  38     format!("rustc {}",
  39             option_env!("CFG_VERSION").unwrap_or("unknown version"))
  40 }
  41
  42 /// Metadata encoding version.
  43 /// NB: increment this if you change the format of metadata such that
  44 /// the rustc version can't be found to compare with `rustc_version()`.
  45 pub const METADATA_VERSION: u8 = 4;
  46
  47 /// Metadata header which includes `METADATA_VERSION`.
  48 /// To get older versions of rustc to ignore this metadata,
  49 /// there are 4 zero bytes at the start, which are treated
  50 /// as a length of 0 by old compilers.
  51 ///
  52 /// This header is followed by the position of the `CrateRoot`,
  53 /// which is encoded as a 32-bit big-endian unsigned integer,
  54 /// and further followed by the rustc version string.
  55 pub const METADATA_HEADER: &[u8; 12] =
  56     &[0, 0, 0, 0, b'r', b'u', b's', b't', 0, 0, 0, METADATA_VERSION];
  57
  58 /// A value of type T referred to by its absolute position
  59 /// in the metadata, and which can be decoded lazily.
  60 ///
  61 /// Metadata is effective a tree, encoded in post-order,
  62 /// and with the root's position written next to the header.
  63 /// That means every single `Lazy` points to some previous
  64 /// location in the metadata and is part of a larger node.
  65 ///
  66 /// The first `Lazy` in a node is encoded as the backwards
  67 /// distance from the position where the containing node
  68 /// starts and where the `Lazy` points to, while the rest
  69 /// use the forward distance from the previous `Lazy`.
  70 /// Distances start at 1, as 0-byte nodes are invalid.
  71 /// Also invalid are nodes being referred in a different
  72 /// order than they were encoded in.
  73 #[must_use]
  74 pub struct Lazy<T> {
  75     pub position: usize,
  76     _marker: PhantomData<T>,
  77 }
  78
  79 impl<T> Lazy<T> {
  80     pub fn with_position(position: usize) -> Lazy<T> {
  81         Lazy {
  82             position,
  83             _marker: PhantomData,
  84         }
  85     }
  86
  87     /// Returns the minimum encoded size of a value of type `T`.
  88     // FIXME(eddyb) Give better estimates for certain types.
  89     pub fn min_size() -> usize {
  90         1
  91     }
  92 }
  93
  94 impl<T> Copy for Lazy<T> {}
  95 impl<T> Clone for Lazy<T> {
  96     fn clone(&self) -> Self {
  97         *self
  98     }
  99 }
 100
 101 impl<T> serialize::UseSpecializedEncodable for Lazy<T> {}
 102 impl<T> serialize::UseSpecializedDecodable for Lazy<T> {}
 103
 104 impl<CTX, T> HashStable<CTX> for Lazy<T> {
 105     fn hash_stable<W: StableHasherResult>(&self,
 106                                           _: &mut CTX,
 107                                           _: &mut StableHasher<W>) {
 108         // There's nothing to do. Whatever got encoded within this Lazy<>
 109         // wrapper has already been hashed.
 110     }
 111 }
 112
 113 /// A sequence of type T referred to by its absolute position
 114 /// in the metadata and length, and which can be decoded lazily.
 115 /// The sequence is a single node for the purposes of `Lazy`.
 116 ///
 117 /// Unlike `Lazy<Vec<T>>`, the length is encoded next to the
 118 /// position, not at the position, which means that the length
 119 /// doesn't need to be known before encoding all the elements.
 120 ///
 121 /// If the length is 0, no position is encoded, but otherwise,
 122 /// the encoding is that of `Lazy`, with the distinction that
 123 /// the minimal distance the length of the sequence, i.e.
 124 /// it's assumed there's no 0-byte element in the sequence.
 125 #[must_use]
 126 pub struct LazySeq<T> {
 127     pub len: usize,
 128     pub position: usize,
 129     _marker: PhantomData<T>,
 130 }
 131
 132 impl<T> LazySeq<T> {
 133     pub fn empty() -> LazySeq<T> {
 134         LazySeq::with_position_and_length(0, 0)
 135     }
 136
 137     pub fn with_position_and_length(position: usize, len: usize) -> LazySeq<T> {
 138         LazySeq {
 139             len,
 140             position,
 141             _marker: PhantomData,
 142         }
 143     }
 144
 145     /// Returns the minimum encoded size of `length` values of type `T`.
 146     pub fn min_size(length: usize) -> usize {
 147         length
 148     }
 149 }
 150
 151 impl<T> Copy for LazySeq<T> {}
 152 impl<T> Clone for LazySeq<T> {
 153     fn clone(&self) -> Self {
 154         *self
 155     }
 156 }
 157
 158 impl<T> serialize::UseSpecializedEncodable for LazySeq<T> {}
 159 impl<T> serialize::UseSpecializedDecodable for LazySeq<T> {}
 160
 161 impl<CTX, T> HashStable<CTX> for LazySeq<T> {
 162     fn hash_stable<W: StableHasherResult>(&self,
 163                                           _: &mut CTX,
 164                                           _: &mut StableHasher<W>) {
 165         // There's nothing to do. Whatever got encoded within this Lazy<>
 166         // wrapper has already been hashed.
 167     }
 168 }
 169
 170 /// Encoding / decoding state for `Lazy` and `LazySeq`.
 171 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
 172 pub enum LazyState {
 173     /// Outside of a metadata node.
 174     NoNode,
 175
 176     /// Inside a metadata node, and before any `Lazy` or `LazySeq`.
 177     /// The position is that of the node itself.
 178     NodeStart(usize),
 179
 180     /// Inside a metadata node, with a previous `Lazy` or `LazySeq`.
 181     /// The position is a conservative estimate of where that
 182     /// previous `Lazy` / `LazySeq` would end (see their comments).
 183     Previous(usize),
 184 }
 185
 186 #[derive(RustcEncodable, RustcDecodable)]
 187 pub struct CrateRoot {
 188     pub name: Symbol,
 189     pub triple: TargetTriple,
 190     pub extra_filename: String,
 191     pub hash: Svh,
 192     pub disambiguator: CrateDisambiguator,
 193     pub panic_strategy: PanicStrategy,
 194     pub edition: Edition,
 195     pub has_global_allocator: bool,
 196     pub has_panic_handler: bool,
 197     pub has_default_lib_allocator: bool,
 198     pub plugin_registrar_fn: Option<DefIndex>,
 199     pub proc_macro_decls_static: Option<DefIndex>,
 200
 201     pub crate_deps: LazySeq<CrateDep>,
 202     pub dylib_dependency_formats: LazySeq<Option<LinkagePreference>>,
 203     pub lib_features: LazySeq<(Symbol, Option<Symbol>)>,
 204     pub lang_items: LazySeq<(DefIndex, usize)>,
 205     pub lang_items_missing: LazySeq<lang_items::LangItem>,
 206     pub native_libraries: LazySeq<NativeLibrary>,
 207     pub foreign_modules: LazySeq<ForeignModule>,
 208     pub source_map: LazySeq<syntax_pos::SourceFile>,
 209     pub def_path_table: Lazy<hir::map::definitions::DefPathTable>,
 210     pub impls: LazySeq<TraitImpls>,
 211     pub exported_symbols: EncodedExportedSymbols,
 212     pub interpret_alloc_index: LazySeq<u32>,
 213
 214     pub index: LazySeq<index::Index>,
 215
 216     pub compiler_builtins: bool,
 217     pub needs_allocator: bool,
 218     pub needs_panic_runtime: bool,
 219     pub no_builtins: bool,
 220     pub panic_runtime: bool,
 221     pub profiler_runtime: bool,
 222     pub sanitizer_runtime: bool,
 223 }
 224
 225 #[derive(RustcEncodable, RustcDecodable)]
 226 pub struct CrateDep {
 227     pub name: ast::Name,
 228     pub hash: Svh,
 229     pub kind: DepKind,
 230     pub extra_filename: String,
 231 }
 232
 233 impl_stable_hash_for!(struct CrateDep {
 234     name,
 235     hash,
 236     kind,
 237     extra_filename
 238 });
 239
 240 #[derive(RustcEncodable, RustcDecodable)]
 241 pub struct TraitImpls {
 242     pub trait_id: (u32, DefIndex),
 243     pub impls: LazySeq<DefIndex>,
 244 }
 245
 246 impl<'a, 'gcx> HashStable<StableHashingContext<'a>> for TraitImpls {
 247     fn hash_stable<W: StableHasherResult>(&self,
 248                                           hcx: &mut StableHashingContext<'a>,
 249                                           hasher: &mut StableHasher<W>) {
 250         let TraitImpls {
 251             trait_id: (krate, def_index),
 252             ref impls,
 253         } = *self;
 254
 255         DefId {
 256             krate: CrateNum::from_u32(krate),
 257             index: def_index
 258         }.hash_stable(hcx, hasher);
 259         impls.hash_stable(hcx, hasher);
 260     }
 261 }
 262
 263 #[derive(RustcEncodable, RustcDecodable)]
 264 pub struct Entry<'tcx> {
 265     pub kind: EntryKind<'tcx>,
 266     pub visibility: Lazy<ty::Visibility>,
 267     pub span: Lazy<Span>,
 268     pub attributes: LazySeq<ast::Attribute>,
 269     pub children: LazySeq<DefIndex>,
 270     pub stability: Option<Lazy<attr::Stability>>,
 271     pub deprecation: Option<Lazy<attr::Deprecation>>,
 272
 273     pub ty: Option<Lazy<Ty<'tcx>>>,
 274     pub inherent_impls: LazySeq<DefIndex>,
 275     pub variances: LazySeq<ty::Variance>,
 276     pub generics: Option<Lazy<ty::Generics>>,
 277     pub predicates: Option<Lazy<ty::GenericPredicates<'tcx>>>,
 278     pub predicates_defined_on: Option<Lazy<ty::GenericPredicates<'tcx>>>,
 279
 280     pub mir: Option<Lazy<mir::Mir<'tcx>>>,
 281 }
 282
 283 impl_stable_hash_for!(struct Entry<'tcx> {
 284     kind,
 285     visibility,
 286     span,
 287     attributes,
 288     children,
 289     stability,
 290     deprecation,
 291     ty,
 292     inherent_impls,
 293     variances,
 294     generics,
 295     predicates,
 296     predicates_defined_on,
 297     mir
 298 });
 299
 300 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
 301 pub enum EntryKind<'tcx> {
 302     Const(ConstQualif, Lazy<RenderedConst>),
 303     ImmStatic,
 304     MutStatic,
 305     ForeignImmStatic,
 306     ForeignMutStatic,
 307     ForeignMod,
 308     ForeignType,
 309     GlobalAsm,
 310     Type,
 311     Existential,
 312     Enum(ReprOptions),
 313     Field,
 314     Variant(Lazy<VariantData<'tcx>>),
 315     Struct(Lazy<VariantData<'tcx>>, ReprOptions),
 316     Union(Lazy<VariantData<'tcx>>, ReprOptions),
 317     Fn(Lazy<FnData<'tcx>>),
 318     ForeignFn(Lazy<FnData<'tcx>>),
 319     Mod(Lazy<ModData>),
 320     MacroDef(Lazy<MacroDef>),
 321     Closure(Lazy<ClosureData<'tcx>>),
 322     Generator(Lazy<GeneratorData<'tcx>>),
 323     Trait(Lazy<TraitData<'tcx>>),
 324     Impl(Lazy<ImplData<'tcx>>),
 325     Method(Lazy<MethodData<'tcx>>),
 326     AssociatedType(AssociatedContainer),
 327     AssociatedExistential(AssociatedContainer),
 328     AssociatedConst(AssociatedContainer, ConstQualif, Lazy<RenderedConst>),
 329 }
 330
 331 impl<'a, 'gcx> HashStable<StableHashingContext<'a>> for EntryKind<'gcx> {
 332     fn hash_stable<W: StableHasherResult>(&self,
 333                                           hcx: &mut StableHashingContext<'a>,
 334                                           hasher: &mut StableHasher<W>) {
 335         mem::discriminant(self).hash_stable(hcx, hasher);
 336         match *self {
 337             EntryKind::ImmStatic        |
 338             EntryKind::MutStatic        |
 339             EntryKind::ForeignImmStatic |
 340             EntryKind::ForeignMutStatic |
 341             EntryKind::ForeignMod       |
 342             EntryKind::GlobalAsm        |
 343             EntryKind::ForeignType      |
 344             EntryKind::Field |
 345             EntryKind::Existential |
 346             EntryKind::Type => {
 347                 // Nothing else to hash here.
 348             }
 349             EntryKind::Const(qualif, ref const_data) => {
 350                 qualif.hash_stable(hcx, hasher);
 351                 const_data.hash_stable(hcx, hasher);
 352             }
 353             EntryKind::Enum(ref repr_options) => {
 354                 repr_options.hash_stable(hcx, hasher);
 355             }
 356             EntryKind::Variant(ref variant_data) => {
 357                 variant_data.hash_stable(hcx, hasher);
 358             }
 359             EntryKind::Struct(ref variant_data, ref repr_options) |
 360             EntryKind::Union(ref variant_data, ref repr_options)  => {
 361                 variant_data.hash_stable(hcx, hasher);
 362                 repr_options.hash_stable(hcx, hasher);
 363             }
 364             EntryKind::Fn(ref fn_data) |
 365             EntryKind::ForeignFn(ref fn_data) => {
 366                 fn_data.hash_stable(hcx, hasher);
 367             }
 368             EntryKind::Mod(ref mod_data) => {
 369                 mod_data.hash_stable(hcx, hasher);
 370             }
 371             EntryKind::MacroDef(ref macro_def) => {
 372                 macro_def.hash_stable(hcx, hasher);
 373             }
 374             EntryKind::Generator(data) => {
 375                 data.hash_stable(hcx, hasher);
 376             }
 377             EntryKind::Closure(closure_data) => {
 378                 closure_data.hash_stable(hcx, hasher);
 379             }
 380             EntryKind::Trait(ref trait_data) => {
 381                 trait_data.hash_stable(hcx, hasher);
 382             }
 383             EntryKind::Impl(ref impl_data) => {
 384                 impl_data.hash_stable(hcx, hasher);
 385             }
 386             EntryKind::Method(ref method_data) => {
 387                 method_data.hash_stable(hcx, hasher);
 388             }
 389             EntryKind::AssociatedExistential(associated_container) |
 390             EntryKind::AssociatedType(associated_container) => {
 391                 associated_container.hash_stable(hcx, hasher);
 392             }
 393             EntryKind::AssociatedConst(associated_container, qualif, ref const_data) => {
 394                 associated_container.hash_stable(hcx, hasher);
 395                 qualif.hash_stable(hcx, hasher);
 396                 const_data.hash_stable(hcx, hasher);
 397             }
 398         }
 399     }
 400 }
 401
 402 /// Additional data for EntryKind::Const and EntryKind::AssociatedConst
 403 #[derive(Clone, Copy, RustcEncodable, RustcDecodable)]
 404 pub struct ConstQualif {
 405     pub mir: u8,
 406     pub ast_promotable: bool,
 407 }
 408
 409 impl_stable_hash_for!(struct ConstQualif { mir, ast_promotable });
 410
 411 /// Contains a constant which has been rendered to a String.
 412 /// Used by rustdoc.
 413 #[derive(RustcEncodable, RustcDecodable)]
 414 pub struct RenderedConst(pub String);
 415
 416 impl<'a> HashStable<StableHashingContext<'a>> for RenderedConst {
 417     #[inline]
 418     fn hash_stable<W: StableHasherResult>(&self,
 419                                           hcx: &mut StableHashingContext<'a>,
 420                                           hasher: &mut StableHasher<W>) {
 421         self.0.hash_stable(hcx, hasher);
 422     }
 423 }
 424
 425 #[derive(RustcEncodable, RustcDecodable)]
 426 pub struct ModData {
 427     pub reexports: LazySeq<def::Export>,
 428 }
 429
 430 impl_stable_hash_for!(struct ModData { reexports });
 431
 432 #[derive(RustcEncodable, RustcDecodable)]
 433 pub struct MacroDef {
 434     pub body: String,
 435     pub legacy: bool,
 436 }
 437
 438 impl_stable_hash_for!(struct MacroDef { body, legacy });
 439
 440 #[derive(RustcEncodable, RustcDecodable)]
 441 pub struct FnData<'tcx> {
 442     pub constness: hir::Constness,
 443     pub arg_names: LazySeq<ast::Name>,
 444     pub sig: Lazy<ty::PolyFnSig<'tcx>>,
 445 }
 446
 447 impl_stable_hash_for!(struct FnData<'tcx> { constness, arg_names, sig });
 448
 449 #[derive(RustcEncodable, RustcDecodable)]
 450 pub struct VariantData<'tcx> {
 451     pub ctor_kind: CtorKind,
 452     pub discr: ty::VariantDiscr,
 453
 454     /// If this is a struct's only variant, this
 455     /// is the index of the "struct ctor" item.
 456     pub struct_ctor: Option<DefIndex>,
 457
 458     /// If this is a tuple struct or variant
 459     /// ctor, this is its "function" signature.
 460     pub ctor_sig: Option<Lazy<ty::PolyFnSig<'tcx>>>,
 461 }
 462
 463 impl_stable_hash_for!(struct VariantData<'tcx> {
 464     ctor_kind,
 465     discr,
 466     struct_ctor,
 467     ctor_sig
 468 });
 469
 470 #[derive(RustcEncodable, RustcDecodable)]
 471 pub struct TraitData<'tcx> {
 472     pub unsafety: hir::Unsafety,
 473     pub paren_sugar: bool,
 474     pub has_auto_impl: bool,
 475     pub is_marker: bool,
 476     pub super_predicates: Lazy<ty::GenericPredicates<'tcx>>,
 477 }
 478
 479 impl_stable_hash_for!(struct TraitData<'tcx> {
 480     unsafety,
 481     paren_sugar,
 482     has_auto_impl,
 483     is_marker,
 484     super_predicates
 485 });
 486
 487 #[derive(RustcEncodable, RustcDecodable)]
 488 pub struct ImplData<'tcx> {
 489     pub polarity: hir::ImplPolarity,
 490     pub defaultness: hir::Defaultness,
 491     pub parent_impl: Option<DefId>,
 492
 493     /// This is `Some` only for impls of `CoerceUnsized`.
 494     pub coerce_unsized_info: Option<ty::adjustment::CoerceUnsizedInfo>,
 495     pub trait_ref: Option<Lazy<ty::TraitRef<'tcx>>>,
 496 }
 497
 498 impl_stable_hash_for!(struct ImplData<'tcx> {
 499     polarity,
 500     defaultness,
 501     parent_impl,
 502     coerce_unsized_info,
 503     trait_ref
 504 });
 505
 506
 507 /// Describes whether the container of an associated item
 508 /// is a trait or an impl and whether, in a trait, it has
 509 /// a default, or an in impl, whether it's marked "default".
 510 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
 511 pub enum AssociatedContainer {
 512     TraitRequired,
 513     TraitWithDefault,
 514     ImplDefault,
 515     ImplFinal,
 516 }
 517
 518 impl_stable_hash_for!(enum ::schema::AssociatedContainer {
 519     TraitRequired,
 520     TraitWithDefault,
 521     ImplDefault,
 522     ImplFinal
 523 });
 524
 525 impl AssociatedContainer {
 526     pub fn with_def_id(&self, def_id: DefId) -> ty::AssociatedItemContainer {
 527         match *self {
 528             AssociatedContainer::TraitRequired |
 529             AssociatedContainer::TraitWithDefault => ty::TraitContainer(def_id),
 530
 531             AssociatedContainer::ImplDefault |
 532             AssociatedContainer::ImplFinal => ty::ImplContainer(def_id),
 533         }
 534     }
 535
 536     pub fn defaultness(&self) -> hir::Defaultness {
 537         match *self {
 538             AssociatedContainer::TraitRequired => hir::Defaultness::Default {
 539                 has_value: false,
 540             },
 541
 542             AssociatedContainer::TraitWithDefault |
 543             AssociatedContainer::ImplDefault => hir::Defaultness::Default {
 544                 has_value: true,
 545             },
 546
 547             AssociatedContainer::ImplFinal => hir::Defaultness::Final,
 548         }
 549     }
 550 }
 551
 552 #[derive(RustcEncodable, RustcDecodable)]
 553 pub struct MethodData<'tcx> {
 554     pub fn_data: FnData<'tcx>,
 555     pub container: AssociatedContainer,
 556     pub has_self: bool,
 557 }
 558 impl_stable_hash_for!(struct MethodData<'tcx> { fn_data, container, has_self });
 559
 560 #[derive(RustcEncodable, RustcDecodable)]
 561 pub struct ClosureData<'tcx> {
 562     pub sig: Lazy<ty::PolyFnSig<'tcx>>,
 563 }
 564 impl_stable_hash_for!(struct ClosureData<'tcx> { sig });
 565
 566 #[derive(RustcEncodable, RustcDecodable)]
 567 pub struct GeneratorData<'tcx> {
 568     pub layout: mir::GeneratorLayout<'tcx>,
 569 }
 570 impl_stable_hash_for!(struct GeneratorData<'tcx> { layout });
 571
 572 // Tags used for encoding Spans:
 573 pub const TAG_VALID_SPAN: u8 = 0;
 574 pub const TAG_INVALID_SPAN: u8 = 1;
 575
 576 #[derive(RustcEncodable, RustcDecodable)]
 577 pub struct EncodedExportedSymbols {
 578     pub position: usize,
 579     pub len: usize,
 580 }