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