src/librustc_metadata/schema.rs

   1 use crate::index;
   2
   3 use rustc::hir;
   4 use rustc::hir::def::{self, CtorKind};
   5 use rustc::hir::def_id::{DefIndex, DefId, CrateNum};
   6 use rustc::ich::StableHashingContext;
   7 use rustc::middle::cstore::{DepKind, LinkagePreference, NativeLibrary, ForeignModule};
   8 use rustc::middle::lang_items;
   9 use rustc::mir;
  10 use rustc::session::CrateDisambiguator;
  11 use rustc::ty::{self, Ty, ReprOptions};
  12 use rustc_target::spec::{PanicStrategy, TargetTriple};
  13 use rustc_data_structures::svh::Svh;
  14
  15 use rustc_serialize as serialize;
  16 use syntax::{ast, attr};
  17 use syntax::edition::Edition;
  18 use syntax::symbol::Symbol;
  19 use syntax_pos::{self, Span};
  20
  21 use std::marker::PhantomData;
  22 use std::mem;
  23
  24 use rustc_data_structures::stable_hasher::{StableHasher, HashStable,
  25                                            StableHasherResult};
  26
  27 pub fn rustc_version() -> String {
  28     format!("rustc {}",
  29             option_env!("CFG_VERSION").unwrap_or("unknown version"))
  30 }
  31
  32 /// Metadata encoding version.
  33 /// N.B., increment this if you change the format of metadata such that
  34 /// the rustc version can't be found to compare with `rustc_version()`.
  35 pub const METADATA_VERSION: u8 = 4;
  36
  37 /// Metadata header which includes `METADATA_VERSION`.
  38 /// To get older versions of rustc to ignore this metadata,
  39 /// there are 4 zero bytes at the start, which are treated
  40 /// as a length of 0 by old compilers.
  41 ///
  42 /// This header is followed by the position of the `CrateRoot`,
  43 /// which is encoded as a 32-bit big-endian unsigned integer,
  44 /// and further followed by the rustc version string.
  45 pub const METADATA_HEADER: &[u8; 12] =
  46     &[0, 0, 0, 0, b'r', b'u', b's', b't', 0, 0, 0, METADATA_VERSION];
  47
  48 /// A value of type T referred to by its absolute position
  49 /// in the metadata, and which can be decoded lazily.
  50 ///
  51 /// Metadata is effective a tree, encoded in post-order,
  52 /// and with the root's position written next to the header.
  53 /// That means every single `Lazy` points to some previous
  54 /// location in the metadata and is part of a larger node.
  55 ///
  56 /// The first `Lazy` in a node is encoded as the backwards
  57 /// distance from the position where the containing node
  58 /// starts and where the `Lazy` points to, while the rest
  59 /// use the forward distance from the previous `Lazy`.
  60 /// Distances start at 1, as 0-byte nodes are invalid.
  61 /// Also invalid are nodes being referred in a different
  62 /// order than they were encoded in.
  63 #[must_use]
  64 pub struct Lazy<T> {
  65     pub position: usize,
  66     _marker: PhantomData<T>,
  67 }
  68
  69 impl<T> Lazy<T> {
  70     pub fn with_position(position: usize) -> Lazy<T> {
  71         Lazy {
  72             position,
  73             _marker: PhantomData,
  74         }
  75     }
  76
  77     /// Returns the minimum encoded size of a value of type `T`.
  78     // FIXME(eddyb) Give better estimates for certain types.
  79     pub fn min_size() -> usize {
  80         1
  81     }
  82 }
  83
  84 impl<T> Copy for Lazy<T> {}
  85 impl<T> Clone for Lazy<T> {
  86     fn clone(&self) -> Self {
  87         *self
  88     }
  89 }
  90
  91 impl<T> serialize::UseSpecializedEncodable for Lazy<T> {}
  92 impl<T> serialize::UseSpecializedDecodable for Lazy<T> {}
  93
  94 impl<CTX, T> HashStable<CTX> for Lazy<T> {
  95     fn hash_stable<W: StableHasherResult>(&self,
  96                                           _: &mut CTX,
  97                                           _: &mut StableHasher<W>) {
  98         // There's nothing to do. Whatever got encoded within this Lazy<>
  99         // wrapper has already been hashed.
 100     }
 101 }
 102
 103 /// A sequence of type T referred to by its absolute position
 104 /// in the metadata and length, and which can be decoded lazily.
 105 /// The sequence is a single node for the purposes of `Lazy`.
 106 ///
 107 /// Unlike `Lazy<Vec<T>>`, the length is encoded next to the
 108 /// position, not at the position, which means that the length
 109 /// doesn't need to be known before encoding all the elements.
 110 ///
 111 /// If the length is 0, no position is encoded, but otherwise,
 112 /// the encoding is that of `Lazy`, with the distinction that
 113 /// the minimal distance the length of the sequence, i.e.
 114 /// it's assumed there's no 0-byte element in the sequence.
 115 #[must_use]
 116 pub struct LazySeq<T> {
 117     pub len: usize,
 118     pub position: usize,
 119     _marker: PhantomData<T>,
 120 }
 121
 122 impl<T> LazySeq<T> {
 123     pub fn empty() -> LazySeq<T> {
 124         LazySeq::with_position_and_length(0, 0)
 125     }
 126
 127     pub fn with_position_and_length(position: usize, len: usize) -> LazySeq<T> {
 128         LazySeq {
 129             len,
 130             position,
 131             _marker: PhantomData,
 132         }
 133     }
 134
 135     /// Returns the minimum encoded size of `length` values of type `T`.
 136     pub fn min_size(length: usize) -> usize {
 137         length
 138     }
 139 }
 140
 141 impl<T> Copy for LazySeq<T> {}
 142 impl<T> Clone for LazySeq<T> {
 143     fn clone(&self) -> Self {
 144         *self
 145     }
 146 }
 147
 148 impl<T> serialize::UseSpecializedEncodable for LazySeq<T> {}
 149 impl<T> serialize::UseSpecializedDecodable for LazySeq<T> {}
 150
 151 impl<CTX, T> HashStable<CTX> for LazySeq<T> {
 152     fn hash_stable<W: StableHasherResult>(&self,
 153                                           _: &mut CTX,
 154                                           _: &mut StableHasher<W>) {
 155         // There's nothing to do. Whatever got encoded within this Lazy<>
 156         // wrapper has already been hashed.
 157     }
 158 }
 159
 160 /// Encoding / decoding state for `Lazy` and `LazySeq`.
 161 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
 162 pub enum LazyState {
 163     /// Outside of a metadata node.
 164     NoNode,
 165
 166     /// Inside a metadata node, and before any `Lazy` or `LazySeq`.
 167     /// The position is that of the node itself.
 168     NodeStart(usize),
 169
 170     /// Inside a metadata node, with a previous `Lazy` or `LazySeq`.
 171     /// The position is a conservative estimate of where that
 172     /// previous `Lazy` / `LazySeq` would end (see their comments).
 173     Previous(usize),
 174 }
 175
 176 #[derive(RustcEncodable, RustcDecodable)]
 177 pub struct CrateRoot {
 178     pub name: Symbol,
 179     pub triple: TargetTriple,
 180     pub extra_filename: String,
 181     pub hash: Svh,
 182     pub disambiguator: CrateDisambiguator,
 183     pub panic_strategy: PanicStrategy,
 184     pub edition: Edition,
 185     pub has_global_allocator: bool,
 186     pub has_panic_handler: bool,
 187     pub has_default_lib_allocator: bool,
 188     pub plugin_registrar_fn: Option<DefIndex>,
 189     pub proc_macro_decls_static: Option<DefIndex>,
 190     pub proc_macro_stability: Option<attr::Stability>,
 191
 192     pub crate_deps: LazySeq<CrateDep>,
 193     pub dylib_dependency_formats: LazySeq<Option<LinkagePreference>>,
 194     pub lib_features: LazySeq<(Symbol, Option<Symbol>)>,
 195     pub lang_items: LazySeq<(DefIndex, usize)>,
 196     pub lang_items_missing: LazySeq<lang_items::LangItem>,
 197     pub native_libraries: LazySeq<NativeLibrary>,
 198     pub foreign_modules: LazySeq<ForeignModule>,
 199     pub source_map: LazySeq<syntax_pos::SourceFile>,
 200     pub def_path_table: Lazy<hir::map::definitions::DefPathTable>,
 201     pub impls: LazySeq<TraitImpls>,
 202     pub exported_symbols: EncodedExportedSymbols,
 203     pub interpret_alloc_index: LazySeq<u32>,
 204
 205     pub index: LazySeq<index::Index>,
 206
 207     pub compiler_builtins: bool,
 208     pub needs_allocator: bool,
 209     pub needs_panic_runtime: bool,
 210     pub no_builtins: bool,
 211     pub panic_runtime: bool,
 212     pub profiler_runtime: bool,
 213     pub sanitizer_runtime: bool,
 214 }
 215
 216 #[derive(RustcEncodable, RustcDecodable)]
 217 pub struct CrateDep {
 218     pub name: ast::Name,
 219     pub hash: Svh,
 220     pub kind: DepKind,
 221     pub extra_filename: String,
 222 }
 223
 224 impl_stable_hash_for!(struct CrateDep {
 225     name,
 226     hash,
 227     kind,
 228     extra_filename
 229 });
 230
 231 #[derive(RustcEncodable, RustcDecodable)]
 232 pub struct TraitImpls {
 233     pub trait_id: (u32, DefIndex),
 234     pub impls: LazySeq<DefIndex>,
 235 }
 236
 237 impl<'a, 'gcx> HashStable<StableHashingContext<'a>> for TraitImpls {
 238     fn hash_stable<W: StableHasherResult>(&self,
 239                                           hcx: &mut StableHashingContext<'a>,
 240                                           hasher: &mut StableHasher<W>) {
 241         let TraitImpls {
 242             trait_id: (krate, def_index),
 243             ref impls,
 244         } = *self;
 245
 246         DefId {
 247             krate: CrateNum::from_u32(krate),
 248             index: def_index
 249         }.hash_stable(hcx, hasher);
 250         impls.hash_stable(hcx, hasher);
 251     }
 252 }
 253
 254 #[derive(RustcEncodable, RustcDecodable)]
 255 pub struct Entry<'tcx> {
 256     pub kind: EntryKind<'tcx>,
 257     pub visibility: Lazy<ty::Visibility>,
 258     pub span: Lazy<Span>,
 259     pub attributes: LazySeq<ast::Attribute>,
 260     pub children: LazySeq<DefIndex>,
 261     pub stability: Option<Lazy<attr::Stability>>,
 262     pub deprecation: Option<Lazy<attr::Deprecation>>,
 263
 264     pub ty: Option<Lazy<Ty<'tcx>>>,
 265     pub inherent_impls: LazySeq<DefIndex>,
 266     pub variances: LazySeq<ty::Variance>,
 267     pub generics: Option<Lazy<ty::Generics>>,
 268     pub predicates: Option<Lazy<ty::GenericPredicates<'tcx>>>,
 269     pub predicates_defined_on: Option<Lazy<ty::GenericPredicates<'tcx>>>,
 270
 271     pub mir: Option<Lazy<mir::Mir<'tcx>>>,
 272 }
 273
 274 impl_stable_hash_for!(struct Entry<'tcx> {
 275     kind,
 276     visibility,
 277     span,
 278     attributes,
 279     children,
 280     stability,
 281     deprecation,
 282     ty,
 283     inherent_impls,
 284     variances,
 285     generics,
 286     predicates,
 287     predicates_defined_on,
 288     mir
 289 });
 290
 291 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
 292 pub enum EntryKind<'tcx> {
 293     Const(ConstQualif, Lazy<RenderedConst>),
 294     ImmStatic,
 295     MutStatic,
 296     ForeignImmStatic,
 297     ForeignMutStatic,
 298     ForeignMod,
 299     ForeignType,
 300     GlobalAsm,
 301     Type,
 302     Existential,
 303     Enum(ReprOptions),
 304     Field,
 305     Variant(Lazy<VariantData<'tcx>>),
 306     Struct(Lazy<VariantData<'tcx>>, ReprOptions),
 307     Union(Lazy<VariantData<'tcx>>, ReprOptions),
 308     Fn(Lazy<FnData<'tcx>>),
 309     ForeignFn(Lazy<FnData<'tcx>>),
 310     Mod(Lazy<ModData>),
 311     MacroDef(Lazy<MacroDef>),
 312     Closure(Lazy<ClosureData<'tcx>>),
 313     Generator(Lazy<GeneratorData<'tcx>>),
 314     Trait(Lazy<TraitData<'tcx>>),
 315     Impl(Lazy<ImplData<'tcx>>),
 316     Method(Lazy<MethodData<'tcx>>),
 317     AssociatedType(AssociatedContainer),
 318     AssociatedExistential(AssociatedContainer),
 319     AssociatedConst(AssociatedContainer, ConstQualif, Lazy<RenderedConst>),
 320     TraitAlias(Lazy<TraitAliasData<'tcx>>),
 321 }
 322
 323 impl<'a, 'gcx> HashStable<StableHashingContext<'a>> for EntryKind<'gcx> {
 324     fn hash_stable<W: StableHasherResult>(&self,
 325                                           hcx: &mut StableHashingContext<'a>,
 326                                           hasher: &mut StableHasher<W>) {
 327         mem::discriminant(self).hash_stable(hcx, hasher);
 328         match *self {
 329             EntryKind::ImmStatic        |
 330             EntryKind::MutStatic        |
 331             EntryKind::ForeignImmStatic |
 332             EntryKind::ForeignMutStatic |
 333             EntryKind::ForeignMod       |
 334             EntryKind::GlobalAsm        |
 335             EntryKind::ForeignType      |
 336             EntryKind::Field |
 337             EntryKind::Existential |
 338             EntryKind::Type => {
 339                 // Nothing else to hash here.
 340             }
 341             EntryKind::Const(qualif, ref const_data) => {
 342                 qualif.hash_stable(hcx, hasher);
 343                 const_data.hash_stable(hcx, hasher);
 344             }
 345             EntryKind::Enum(ref repr_options) => {
 346                 repr_options.hash_stable(hcx, hasher);
 347             }
 348             EntryKind::Variant(ref variant_data) => {
 349                 variant_data.hash_stable(hcx, hasher);
 350             }
 351             EntryKind::Struct(ref variant_data, ref repr_options) |
 352             EntryKind::Union(ref variant_data, ref repr_options)  => {
 353                 variant_data.hash_stable(hcx, hasher);
 354                 repr_options.hash_stable(hcx, hasher);
 355             }
 356             EntryKind::Fn(ref fn_data) |
 357             EntryKind::ForeignFn(ref fn_data) => {
 358                 fn_data.hash_stable(hcx, hasher);
 359             }
 360             EntryKind::Mod(ref mod_data) => {
 361                 mod_data.hash_stable(hcx, hasher);
 362             }
 363             EntryKind::MacroDef(ref macro_def) => {
 364                 macro_def.hash_stable(hcx, hasher);
 365             }
 366             EntryKind::Generator(data) => {
 367                 data.hash_stable(hcx, hasher);
 368             }
 369             EntryKind::Closure(closure_data) => {
 370                 closure_data.hash_stable(hcx, hasher);
 371             }
 372             EntryKind::Trait(ref trait_data) => {
 373                 trait_data.hash_stable(hcx, hasher);
 374             }
 375             EntryKind::TraitAlias(ref trait_alias_data) => {
 376                 trait_alias_data.hash_stable(hcx, hasher);
 377             }
 378             EntryKind::Impl(ref impl_data) => {
 379                 impl_data.hash_stable(hcx, hasher);
 380             }
 381             EntryKind::Method(ref method_data) => {
 382                 method_data.hash_stable(hcx, hasher);
 383             }
 384             EntryKind::AssociatedExistential(associated_container) |
 385             EntryKind::AssociatedType(associated_container) => {
 386                 associated_container.hash_stable(hcx, hasher);
 387             }
 388             EntryKind::AssociatedConst(associated_container, qualif, ref const_data) => {
 389                 associated_container.hash_stable(hcx, hasher);
 390                 qualif.hash_stable(hcx, hasher);
 391                 const_data.hash_stable(hcx, hasher);
 392             }
 393         }
 394     }
 395 }
 396
 397 /// Additional data for EntryKind::Const and EntryKind::AssociatedConst
 398 #[derive(Clone, Copy, RustcEncodable, RustcDecodable)]
 399 pub struct ConstQualif {
 400     pub mir: u8,
 401     pub ast_promotable: bool,
 402 }
 403
 404 impl_stable_hash_for!(struct ConstQualif { mir, ast_promotable });
 405
 406 /// Contains a constant which has been rendered to a String.
 407 /// Used by rustdoc.
 408 #[derive(RustcEncodable, RustcDecodable)]
 409 pub struct RenderedConst(pub String);
 410
 411 impl<'a> HashStable<StableHashingContext<'a>> for RenderedConst {
 412     #[inline]
 413     fn hash_stable<W: StableHasherResult>(&self,
 414                                           hcx: &mut StableHashingContext<'a>,
 415                                           hasher: &mut StableHasher<W>) {
 416         self.0.hash_stable(hcx, hasher);
 417     }
 418 }
 419
 420 #[derive(RustcEncodable, RustcDecodable)]
 421 pub struct ModData {
 422     pub reexports: LazySeq<def::Export>,
 423 }
 424
 425 impl_stable_hash_for!(struct ModData { reexports });
 426
 427 #[derive(RustcEncodable, RustcDecodable)]
 428 pub struct MacroDef {
 429     pub body: String,
 430     pub legacy: bool,
 431 }
 432
 433 impl_stable_hash_for!(struct MacroDef { body, legacy });
 434
 435 #[derive(RustcEncodable, RustcDecodable)]
 436 pub struct FnData<'tcx> {
 437     pub constness: hir::Constness,
 438     pub arg_names: LazySeq<ast::Name>,
 439     pub sig: Lazy<ty::PolyFnSig<'tcx>>,
 440 }
 441
 442 impl_stable_hash_for!(struct FnData<'tcx> { constness, arg_names, sig });
 443
 444 #[derive(RustcEncodable, RustcDecodable)]
 445 pub struct VariantData<'tcx> {
 446     pub ctor_kind: CtorKind,
 447     pub discr: ty::VariantDiscr,
 448     /// If this is unit or tuple-variant/struct, then this is the index of the ctor id.
 449     pub ctor: Option<DefIndex>,
 450     /// If this is a tuple struct or variant
 451     /// ctor, this is its "function" signature.
 452     pub ctor_sig: Option<Lazy<ty::PolyFnSig<'tcx>>>,
 453 }
 454
 455 impl_stable_hash_for!(struct VariantData<'tcx> {
 456     ctor_kind,
 457     discr,
 458     ctor,
 459     ctor_sig
 460 });
 461
 462 #[derive(RustcEncodable, RustcDecodable)]
 463 pub struct TraitData<'tcx> {
 464     pub unsafety: hir::Unsafety,
 465     pub paren_sugar: bool,
 466     pub has_auto_impl: bool,
 467     pub is_marker: bool,
 468     pub super_predicates: Lazy<ty::GenericPredicates<'tcx>>,
 469 }
 470
 471 impl_stable_hash_for!(struct TraitData<'tcx> {
 472     unsafety,
 473     paren_sugar,
 474     has_auto_impl,
 475     is_marker,
 476     super_predicates
 477 });
 478
 479 #[derive(RustcEncodable, RustcDecodable)]
 480 pub struct TraitAliasData<'tcx> {
 481     pub super_predicates: Lazy<ty::GenericPredicates<'tcx>>,
 482 }
 483
 484 impl_stable_hash_for!(struct TraitAliasData<'tcx> {
 485     super_predicates
 486 });
 487
 488 #[derive(RustcEncodable, RustcDecodable)]
 489 pub struct ImplData<'tcx> {
 490     pub polarity: hir::ImplPolarity,
 491     pub defaultness: hir::Defaultness,
 492     pub parent_impl: Option<DefId>,
 493
 494     /// This is `Some` only for impls of `CoerceUnsized`.
 495     pub coerce_unsized_info: Option<ty::adjustment::CoerceUnsizedInfo>,
 496     pub trait_ref: Option<Lazy<ty::TraitRef<'tcx>>>,
 497 }
 498
 499 impl_stable_hash_for!(struct ImplData<'tcx> {
 500     polarity,
 501     defaultness,
 502     parent_impl,
 503     coerce_unsized_info,
 504     trait_ref
 505 });
 506
 507
 508 /// Describes whether the container of an associated item
 509 /// is a trait or an impl and whether, in a trait, it has
 510 /// a default, or an in impl, whether it's marked "default".
 511 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
 512 pub enum AssociatedContainer {
 513     TraitRequired,
 514     TraitWithDefault,
 515     ImplDefault,
 516     ImplFinal,
 517 }
 518
 519 impl_stable_hash_for!(enum crate::schema::AssociatedContainer {
 520     TraitRequired,
 521     TraitWithDefault,
 522     ImplDefault,
 523     ImplFinal
 524 });
 525
 526 impl AssociatedContainer {
 527     pub fn with_def_id(&self, def_id: DefId) -> ty::AssociatedItemContainer {
 528         match *self {
 529             AssociatedContainer::TraitRequired |
 530             AssociatedContainer::TraitWithDefault => ty::TraitContainer(def_id),
 531
 532             AssociatedContainer::ImplDefault |
 533             AssociatedContainer::ImplFinal => ty::ImplContainer(def_id),
 534         }
 535     }
 536
 537     pub fn defaultness(&self) -> hir::Defaultness {
 538         match *self {
 539             AssociatedContainer::TraitRequired => hir::Defaultness::Default {
 540                 has_value: false,
 541             },
 542
 543             AssociatedContainer::TraitWithDefault |
 544             AssociatedContainer::ImplDefault => hir::Defaultness::Default {
 545                 has_value: true,
 546             },
 547
 548             AssociatedContainer::ImplFinal => hir::Defaultness::Final,
 549         }
 550     }
 551 }
 552
 553 #[derive(RustcEncodable, RustcDecodable)]
 554 pub struct MethodData<'tcx> {
 555     pub fn_data: FnData<'tcx>,
 556     pub container: AssociatedContainer,
 557     pub has_self: bool,
 558 }
 559 impl_stable_hash_for!(struct MethodData<'tcx> { fn_data, container, has_self });
 560
 561 #[derive(RustcEncodable, RustcDecodable)]
 562 pub struct ClosureData<'tcx> {
 563     pub sig: Lazy<ty::PolyFnSig<'tcx>>,
 564 }
 565 impl_stable_hash_for!(struct ClosureData<'tcx> { sig });
 566
 567 #[derive(RustcEncodable, RustcDecodable)]
 568 pub struct GeneratorData<'tcx> {
 569     pub layout: mir::GeneratorLayout<'tcx>,
 570 }
 571 impl_stable_hash_for!(struct GeneratorData<'tcx> { layout });
 572
 573 // Tags used for encoding Spans:
 574 pub const TAG_VALID_SPAN: u8 = 0;
 575 pub const TAG_INVALID_SPAN: u8 = 1;
 576
 577 #[derive(RustcEncodable, RustcDecodable)]
 578 pub struct EncodedExportedSymbols {
 579     pub position: usize,
 580     pub len: usize,
 581 }