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 astencode;
  12 use index;
  13
  14 use rustc::hir;
  15 use rustc::hir::def::{self, CtorKind};
  16 use rustc::hir::def_id::{DefIndex, DefId, CrateNum};
  17 use rustc::ich::StableHashingContext;
  18 use rustc::middle::cstore::{DepKind, LinkagePreference, NativeLibrary};
  19 use rustc::middle::lang_items;
  20 use rustc::mir;
  21 use rustc::session::CrateDisambiguator;
  22 use rustc::ty::{self, Ty, ReprOptions};
  23 use rustc_back::PanicStrategy;
  24
  25 use rustc_serialize as serialize;
  26 use syntax::{ast, attr};
  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: String,
 189     pub hash: hir::svh::Svh,
 190     pub disambiguator: CrateDisambiguator,
 191     pub panic_strategy: PanicStrategy,
 192     pub has_global_allocator: bool,
 193     pub has_default_lib_allocator: bool,
 194     pub plugin_registrar_fn: Option<DefIndex>,
 195     pub macro_derive_registrar: Option<DefIndex>,
 196
 197     pub crate_deps: LazySeq<CrateDep>,
 198     pub dylib_dependency_formats: LazySeq<Option<LinkagePreference>>,
 199     pub lang_items: LazySeq<(DefIndex, usize)>,
 200     pub lang_items_missing: LazySeq<lang_items::LangItem>,
 201     pub native_libraries: LazySeq<NativeLibrary>,
 202     pub codemap: LazySeq<syntax_pos::FileMap>,
 203     pub def_path_table: Lazy<hir::map::definitions::DefPathTable>,
 204     pub impls: LazySeq<TraitImpls>,
 205     pub exported_symbols: LazySeq<DefIndex>,
 206     pub index: LazySeq<index::Index>,
 207 }
 208
 209 #[derive(RustcEncodable, RustcDecodable)]
 210 pub struct CrateDep {
 211     pub name: ast::Name,
 212     pub hash: hir::svh::Svh,
 213     pub kind: DepKind,
 214 }
 215
 216 impl_stable_hash_for!(struct CrateDep {
 217     name,
 218     hash,
 219     kind
 220 });
 221
 222 #[derive(RustcEncodable, RustcDecodable)]
 223 pub struct TraitImpls {
 224     pub trait_id: (u32, DefIndex),
 225     pub impls: LazySeq<DefIndex>,
 226 }
 227
 228 impl<'gcx> HashStable<StableHashingContext<'gcx>> for TraitImpls {
 229     fn hash_stable<W: StableHasherResult>(&self,
 230                                           hcx: &mut StableHashingContext<'gcx>,
 231                                           hasher: &mut StableHasher<W>) {
 232         let TraitImpls {
 233             trait_id: (krate, def_index),
 234             ref impls,
 235         } = *self;
 236
 237         DefId {
 238             krate: CrateNum::from_u32(krate),
 239             index: def_index
 240         }.hash_stable(hcx, hasher);
 241         impls.hash_stable(hcx, hasher);
 242     }
 243 }
 244
 245 #[derive(RustcEncodable, RustcDecodable)]
 246 pub struct Entry<'tcx> {
 247     pub kind: EntryKind<'tcx>,
 248     pub visibility: Lazy<ty::Visibility>,
 249     pub span: Lazy<Span>,
 250     pub attributes: LazySeq<ast::Attribute>,
 251     pub children: LazySeq<DefIndex>,
 252     pub stability: Option<Lazy<attr::Stability>>,
 253     pub deprecation: Option<Lazy<attr::Deprecation>>,
 254
 255     pub ty: Option<Lazy<Ty<'tcx>>>,
 256     pub inherent_impls: LazySeq<DefIndex>,
 257     pub variances: LazySeq<ty::Variance>,
 258     pub generics: Option<Lazy<ty::Generics>>,
 259     pub predicates: Option<Lazy<ty::GenericPredicates<'tcx>>>,
 260
 261     pub ast: Option<Lazy<astencode::Ast<'tcx>>>,
 262     pub mir: Option<Lazy<mir::Mir<'tcx>>>,
 263 }
 264
 265 impl_stable_hash_for!(struct Entry<'tcx> {
 266     kind,
 267     visibility,
 268     span,
 269     attributes,
 270     children,
 271     stability,
 272     deprecation,
 273     ty,
 274     inherent_impls,
 275     variances,
 276     generics,
 277     predicates,
 278     ast,
 279     mir
 280 });
 281
 282 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
 283 pub enum EntryKind<'tcx> {
 284     Const(u8),
 285     ImmStatic,
 286     MutStatic,
 287     ForeignImmStatic,
 288     ForeignMutStatic,
 289     ForeignMod,
 290     ForeignType,
 291     GlobalAsm,
 292     Type,
 293     Enum(ReprOptions),
 294     Field,
 295     Variant(Lazy<VariantData<'tcx>>),
 296     Struct(Lazy<VariantData<'tcx>>, ReprOptions),
 297     Union(Lazy<VariantData<'tcx>>, ReprOptions),
 298     Fn(Lazy<FnData<'tcx>>),
 299     ForeignFn(Lazy<FnData<'tcx>>),
 300     Mod(Lazy<ModData>),
 301     MacroDef(Lazy<MacroDef>),
 302     Closure(Lazy<ClosureData<'tcx>>),
 303     Generator(Lazy<GeneratorData<'tcx>>),
 304     Trait(Lazy<TraitData<'tcx>>),
 305     Impl(Lazy<ImplData<'tcx>>),
 306     AutoImpl(Lazy<ImplData<'tcx>>),
 307     Method(Lazy<MethodData<'tcx>>),
 308     AssociatedType(AssociatedContainer),
 309     AssociatedConst(AssociatedContainer, u8),
 310 }
 311
 312 impl<'gcx> HashStable<StableHashingContext<'gcx>> for EntryKind<'gcx> {
 313     fn hash_stable<W: StableHasherResult>(&self,
 314                                           hcx: &mut StableHashingContext<'gcx>,
 315                                           hasher: &mut StableHasher<W>) {
 316         mem::discriminant(self).hash_stable(hcx, hasher);
 317         match *self {
 318             EntryKind::ImmStatic        |
 319             EntryKind::MutStatic        |
 320             EntryKind::ForeignImmStatic |
 321             EntryKind::ForeignMutStatic |
 322             EntryKind::ForeignMod       |
 323             EntryKind::GlobalAsm        |
 324             EntryKind::ForeignType      |
 325             EntryKind::Field |
 326             EntryKind::Type => {
 327                 // Nothing else to hash here.
 328             }
 329             EntryKind::Const(qualif) => {
 330                 qualif.hash_stable(hcx, hasher);
 331             }
 332             EntryKind::Enum(ref repr_options) => {
 333                 repr_options.hash_stable(hcx, hasher);
 334             }
 335             EntryKind::Variant(ref variant_data) => {
 336                 variant_data.hash_stable(hcx, hasher);
 337             }
 338             EntryKind::Struct(ref variant_data, ref repr_options) |
 339             EntryKind::Union(ref variant_data, ref repr_options)  => {
 340                 variant_data.hash_stable(hcx, hasher);
 341                 repr_options.hash_stable(hcx, hasher);
 342             }
 343             EntryKind::Fn(ref fn_data) |
 344             EntryKind::ForeignFn(ref fn_data) => {
 345                 fn_data.hash_stable(hcx, hasher);
 346             }
 347             EntryKind::Mod(ref mod_data) => {
 348                 mod_data.hash_stable(hcx, hasher);
 349             }
 350             EntryKind::MacroDef(ref macro_def) => {
 351                 macro_def.hash_stable(hcx, hasher);
 352             }
 353             EntryKind::Generator(data) => {
 354                 data.hash_stable(hcx, hasher);
 355             }
 356             EntryKind::Closure(closure_data) => {
 357                 closure_data.hash_stable(hcx, hasher);
 358             }
 359             EntryKind::Trait(ref trait_data) => {
 360                 trait_data.hash_stable(hcx, hasher);
 361             }
 362             EntryKind::AutoImpl(ref impl_data) |
 363             EntryKind::Impl(ref impl_data) => {
 364                 impl_data.hash_stable(hcx, hasher);
 365             }
 366             EntryKind::Method(ref method_data) => {
 367                 method_data.hash_stable(hcx, hasher);
 368             }
 369             EntryKind::AssociatedType(associated_container) => {
 370                 associated_container.hash_stable(hcx, hasher);
 371             }
 372             EntryKind::AssociatedConst(associated_container, qualif) => {
 373                 associated_container.hash_stable(hcx, hasher);
 374                 qualif.hash_stable(hcx, hasher);
 375             }
 376         }
 377     }
 378 }
 379
 380 #[derive(RustcEncodable, RustcDecodable)]
 381 pub struct ModData {
 382     pub reexports: LazySeq<def::Export>,
 383 }
 384
 385 impl_stable_hash_for!(struct ModData { reexports });
 386
 387 #[derive(RustcEncodable, RustcDecodable)]
 388 pub struct MacroDef {
 389     pub body: String,
 390     pub legacy: bool,
 391 }
 392
 393 impl_stable_hash_for!(struct MacroDef { body, legacy });
 394
 395 #[derive(RustcEncodable, RustcDecodable)]
 396 pub struct FnData<'tcx> {
 397     pub constness: hir::Constness,
 398     pub arg_names: LazySeq<ast::Name>,
 399     pub sig: Lazy<ty::PolyFnSig<'tcx>>,
 400 }
 401
 402 impl_stable_hash_for!(struct FnData<'tcx> { constness, arg_names, sig });
 403
 404 #[derive(RustcEncodable, RustcDecodable)]
 405 pub struct VariantData<'tcx> {
 406     pub ctor_kind: CtorKind,
 407     pub discr: ty::VariantDiscr,
 408
 409     /// If this is a struct's only variant, this
 410     /// is the index of the "struct ctor" item.
 411     pub struct_ctor: Option<DefIndex>,
 412
 413     /// If this is a tuple struct or variant
 414     /// ctor, this is its "function" signature.
 415     pub ctor_sig: Option<Lazy<ty::PolyFnSig<'tcx>>>,
 416 }
 417
 418 impl_stable_hash_for!(struct VariantData<'tcx> {
 419     ctor_kind,
 420     discr,
 421     struct_ctor,
 422     ctor_sig
 423 });
 424
 425 #[derive(RustcEncodable, RustcDecodable)]
 426 pub struct TraitData<'tcx> {
 427     pub unsafety: hir::Unsafety,
 428     pub paren_sugar: bool,
 429     pub has_auto_impl: bool,
 430     pub super_predicates: Lazy<ty::GenericPredicates<'tcx>>,
 431 }
 432
 433 impl_stable_hash_for!(struct TraitData<'tcx> {
 434     unsafety,
 435     paren_sugar,
 436     has_auto_impl,
 437     super_predicates
 438 });
 439
 440 #[derive(RustcEncodable, RustcDecodable)]
 441 pub struct ImplData<'tcx> {
 442     pub polarity: hir::ImplPolarity,
 443     pub defaultness: hir::Defaultness,
 444     pub parent_impl: Option<DefId>,
 445
 446     /// This is `Some` only for impls of `CoerceUnsized`.
 447     pub coerce_unsized_info: Option<ty::adjustment::CoerceUnsizedInfo>,
 448     pub trait_ref: Option<Lazy<ty::TraitRef<'tcx>>>,
 449 }
 450
 451 impl_stable_hash_for!(struct ImplData<'tcx> {
 452     polarity,
 453     defaultness,
 454     parent_impl,
 455     coerce_unsized_info,
 456     trait_ref
 457 });
 458
 459
 460 /// Describes whether the container of an associated item
 461 /// is a trait or an impl and whether, in a trait, it has
 462 /// a default, or an in impl, whether it's marked "default".
 463 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
 464 pub enum AssociatedContainer {
 465     TraitRequired,
 466     TraitWithDefault,
 467     ImplDefault,
 468     ImplFinal,
 469 }
 470
 471 impl_stable_hash_for!(enum ::schema::AssociatedContainer {
 472     TraitRequired,
 473     TraitWithDefault,
 474     ImplDefault,
 475     ImplFinal
 476 });
 477
 478 impl AssociatedContainer {
 479     pub fn with_def_id(&self, def_id: DefId) -> ty::AssociatedItemContainer {
 480         match *self {
 481             AssociatedContainer::TraitRequired |
 482             AssociatedContainer::TraitWithDefault => ty::TraitContainer(def_id),
 483
 484             AssociatedContainer::ImplDefault |
 485             AssociatedContainer::ImplFinal => ty::ImplContainer(def_id),
 486         }
 487     }
 488
 489     pub fn defaultness(&self) -> hir::Defaultness {
 490         match *self {
 491             AssociatedContainer::TraitRequired => hir::Defaultness::Default {
 492                 has_value: false,
 493             },
 494
 495             AssociatedContainer::TraitWithDefault |
 496             AssociatedContainer::ImplDefault => hir::Defaultness::Default {
 497                 has_value: true,
 498             },
 499
 500             AssociatedContainer::ImplFinal => hir::Defaultness::Final,
 501         }
 502     }
 503 }
 504
 505 #[derive(RustcEncodable, RustcDecodable)]
 506 pub struct MethodData<'tcx> {
 507     pub fn_data: FnData<'tcx>,
 508     pub container: AssociatedContainer,
 509     pub has_self: bool,
 510 }
 511 impl_stable_hash_for!(struct MethodData<'tcx> { fn_data, container, has_self });
 512
 513 #[derive(RustcEncodable, RustcDecodable)]
 514 pub struct ClosureData<'tcx> {
 515     pub sig: Lazy<ty::PolyFnSig<'tcx>>,
 516 }
 517 impl_stable_hash_for!(struct ClosureData<'tcx> { sig });
 518
 519 #[derive(RustcEncodable, RustcDecodable)]
 520 pub struct GeneratorData<'tcx> {
 521     pub layout: mir::GeneratorLayout<'tcx>,
 522 }
 523 impl_stable_hash_for!(struct GeneratorData<'tcx> { layout });