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.
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.
15 use rustc::hir::def::{self, CtorKind};
16 use rustc::hir::def_id::{DefIndex, DefId};
17 use rustc::middle::cstore::{DepKind, LinkagePreference, NativeLibrary};
18 use rustc::middle::lang_items;
20 use rustc::ty::{self, Ty};
21 use rustc_back::PanicStrategy;
23 use rustc_serialize as serialize;
24 use syntax::{ast, attr};
25 use syntax::symbol::Symbol;
26 use syntax_pos::{self, Span};
28 use std::marker::PhantomData;
32 pub fn rustc_version() -> String {
34 option_env!("CFG_VERSION").unwrap_or("unknown version"))
37 /// Metadata encoding version.
38 /// NB: increment this if you change the format of metadata such that
39 /// the rustc version can't be found to compare with `rustc_version()`.
40 pub const METADATA_VERSION: u8 = 4;
42 /// Metadata header which includes `METADATA_VERSION`.
43 /// To get older versions of rustc to ignore this metadata,
44 /// there are 4 zero bytes at the start, which are treated
45 /// as a length of 0 by old compilers.
47 /// This header is followed by the position of the `CrateRoot`,
48 /// which is encoded as a 32-bit big-endian unsigned integer,
49 /// and further followed by the rustc version string.
50 pub const METADATA_HEADER: &'static [u8; 12] =
51 &[0, 0, 0, 0, b'r', b'u', b's', b't', 0, 0, 0, METADATA_VERSION];
53 /// The shorthand encoding uses an enum's variant index `usize`
54 /// and is offset by this value so it never matches a real variant.
55 /// This offset is also chosen so that the first byte is never < 0x80.
56 pub const SHORTHAND_OFFSET: usize = 0x80;
58 /// A value of type T referred to by its absolute position
59 /// in the metadata, and which can be decoded lazily.
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.
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.
76 _marker: PhantomData<T>,
80 pub fn with_position(position: usize) -> Lazy<T> {
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 {
94 impl<T> Copy for Lazy<T> {}
95 impl<T> Clone for Lazy<T> {
96 fn clone(&self) -> Self {
101 impl<T> serialize::UseSpecializedEncodable for Lazy<T> {}
102 impl<T> serialize::UseSpecializedDecodable for Lazy<T> {}
104 /// A sequence of type T referred to by its absolute position
105 /// in the metadata and length, and which can be decoded lazily.
106 /// The sequence is a single node for the purposes of `Lazy`.
108 /// Unlike `Lazy<Vec<T>>`, the length is encoded next to the
109 /// position, not at the position, which means that the length
110 /// doesn't need to be known before encoding all the elements.
112 /// If the length is 0, no position is encoded, but otherwise,
113 /// the encoding is that of `Lazy`, with the distinction that
114 /// the minimal distance the length of the sequence, i.e.
115 /// it's assumed there's no 0-byte element in the sequence.
117 pub struct LazySeq<T> {
120 _marker: PhantomData<T>,
124 pub fn empty() -> LazySeq<T> {
125 LazySeq::with_position_and_length(0, 0)
128 pub fn with_position_and_length(position: usize, len: usize) -> LazySeq<T> {
132 _marker: PhantomData,
136 /// Returns the minimum encoded size of `length` values of type `T`.
137 pub fn min_size(length: usize) -> usize {
142 impl<T> Copy for LazySeq<T> {}
143 impl<T> Clone for LazySeq<T> {
144 fn clone(&self) -> Self {
149 impl<T> serialize::UseSpecializedEncodable for LazySeq<T> {}
150 impl<T> serialize::UseSpecializedDecodable for LazySeq<T> {}
152 /// Encoding / decoding state for `Lazy` and `LazySeq`.
153 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
155 /// Outside of a metadata node.
158 /// Inside a metadata node, and before any `Lazy` or `LazySeq`.
159 /// The position is that of the node itself.
162 /// Inside a metadata node, with a previous `Lazy` or `LazySeq`.
163 /// The position is a conservative estimate of where that
164 /// previous `Lazy` / `LazySeq` would end (see their comments).
168 #[derive(RustcEncodable, RustcDecodable)]
169 pub struct CrateRoot {
172 pub hash: hir::svh::Svh,
173 pub disambiguator: Symbol,
174 pub panic_strategy: PanicStrategy,
175 pub plugin_registrar_fn: Option<DefIndex>,
176 pub macro_derive_registrar: Option<DefIndex>,
178 pub crate_deps: LazySeq<CrateDep>,
179 pub dylib_dependency_formats: LazySeq<Option<LinkagePreference>>,
180 pub lang_items: LazySeq<(DefIndex, usize)>,
181 pub lang_items_missing: LazySeq<lang_items::LangItem>,
182 pub native_libraries: LazySeq<NativeLibrary>,
183 pub codemap: LazySeq<syntax_pos::FileMap>,
184 pub def_path_table: Lazy<hir::map::definitions::DefPathTable>,
185 pub impls: LazySeq<TraitImpls>,
186 pub exported_symbols: LazySeq<DefIndex>,
187 pub index: LazySeq<index::Index>,
190 #[derive(RustcEncodable, RustcDecodable)]
191 pub struct CrateDep {
193 pub hash: hir::svh::Svh,
197 #[derive(RustcEncodable, RustcDecodable)]
198 pub struct TraitImpls {
199 pub trait_id: (u32, DefIndex),
200 pub impls: LazySeq<DefIndex>,
203 #[derive(RustcEncodable, RustcDecodable)]
204 pub struct Entry<'tcx> {
205 pub kind: EntryKind<'tcx>,
206 pub visibility: Lazy<ty::Visibility>,
207 pub span: Lazy<Span>,
208 pub attributes: LazySeq<ast::Attribute>,
209 pub children: LazySeq<DefIndex>,
210 pub stability: Option<Lazy<attr::Stability>>,
211 pub deprecation: Option<Lazy<attr::Deprecation>>,
213 pub ty: Option<Lazy<Ty<'tcx>>>,
214 pub inherent_impls: LazySeq<DefIndex>,
215 pub variances: LazySeq<ty::Variance>,
216 pub generics: Option<Lazy<Generics<'tcx>>>,
217 pub predicates: Option<Lazy<ty::GenericPredicates<'tcx>>>,
219 pub ast: Option<Lazy<astencode::Ast<'tcx>>>,
220 pub mir: Option<Lazy<mir::Mir<'tcx>>>,
223 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
224 pub enum EntryKind<'tcx> {
234 Variant(Lazy<VariantData>),
235 Struct(Lazy<VariantData>),
236 Union(Lazy<VariantData>),
238 ForeignFn(Lazy<FnData>),
240 MacroDef(Lazy<MacroDef>),
241 Closure(Lazy<ClosureData<'tcx>>),
242 Trait(Lazy<TraitData<'tcx>>),
243 Impl(Lazy<ImplData<'tcx>>),
244 DefaultImpl(Lazy<ImplData<'tcx>>),
245 Method(Lazy<MethodData>),
246 AssociatedType(AssociatedContainer),
247 AssociatedConst(AssociatedContainer),
250 /// A copy of `ty::Generics` which allows lazy decoding of
251 /// `regions` and `types` (e.g. knowing the number of type
252 /// and lifetime parameters before `TyCtxt` is created).
253 #[derive(RustcEncodable, RustcDecodable)]
254 pub struct Generics<'tcx> {
255 pub parent: Option<DefId>,
256 pub parent_regions: u32,
257 pub parent_types: u32,
258 pub regions: LazySeq<ty::RegionParameterDef<'tcx>>,
259 pub types: LazySeq<ty::TypeParameterDef<'tcx>>,
263 #[derive(RustcEncodable, RustcDecodable)]
265 pub reexports: LazySeq<def::Export>,
268 #[derive(RustcEncodable, RustcDecodable)]
269 pub struct MacroDef {
273 #[derive(RustcEncodable, RustcDecodable)]
275 pub constness: hir::Constness,
276 pub arg_names: LazySeq<ast::Name>,
279 #[derive(RustcEncodable, RustcDecodable)]
280 pub struct VariantData {
281 pub ctor_kind: CtorKind,
284 /// If this is a struct's only variant, this
285 /// is the index of the "struct ctor" item.
286 pub struct_ctor: Option<DefIndex>,
289 #[derive(RustcEncodable, RustcDecodable)]
290 pub struct TraitData<'tcx> {
291 pub unsafety: hir::Unsafety,
292 pub paren_sugar: bool,
293 pub has_default_impl: bool,
294 pub super_predicates: Lazy<ty::GenericPredicates<'tcx>>,
297 #[derive(RustcEncodable, RustcDecodable)]
298 pub struct ImplData<'tcx> {
299 pub polarity: hir::ImplPolarity,
300 pub parent_impl: Option<DefId>,
301 pub coerce_unsized_kind: Option<ty::adjustment::CustomCoerceUnsized>,
302 pub trait_ref: Option<Lazy<ty::TraitRef<'tcx>>>,
305 /// Describes whether the container of an associated item
306 /// is a trait or an impl and whether, in a trait, it has
307 /// a default, or an in impl, whether it's marked "default".
308 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
309 pub enum AssociatedContainer {
316 impl AssociatedContainer {
317 pub fn with_def_id(&self, def_id: DefId) -> ty::AssociatedItemContainer {
319 AssociatedContainer::TraitRequired |
320 AssociatedContainer::TraitWithDefault => ty::TraitContainer(def_id),
322 AssociatedContainer::ImplDefault |
323 AssociatedContainer::ImplFinal => ty::ImplContainer(def_id),
327 pub fn defaultness(&self) -> hir::Defaultness {
329 AssociatedContainer::TraitRequired => hir::Defaultness::Default {
333 AssociatedContainer::TraitWithDefault |
334 AssociatedContainer::ImplDefault => hir::Defaultness::Default {
338 AssociatedContainer::ImplFinal => hir::Defaultness::Final,
343 #[derive(RustcEncodable, RustcDecodable)]
344 pub struct MethodData {
346 pub container: AssociatedContainer,
350 #[derive(RustcEncodable, RustcDecodable)]
351 pub struct ClosureData<'tcx> {
352 pub kind: ty::ClosureKind,
353 pub ty: Lazy<ty::ClosureTy<'tcx>>,