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::const_val::ConstVal;
18 use rustc::middle::cstore::{DepKind, LinkagePreference, NativeLibrary};
19 use rustc::middle::lang_items;
21 use rustc::ty::{self, Ty, ReprOptions};
22 use rustc_back::PanicStrategy;
24 use rustc_serialize as serialize;
25 use syntax::{ast, attr};
26 use syntax::symbol::Symbol;
27 use syntax_pos::{self, Span};
29 use std::marker::PhantomData;
31 pub fn rustc_version() -> String {
33 option_env!("CFG_VERSION").unwrap_or("unknown version"))
36 /// Metadata encoding version.
37 /// NB: increment this if you change the format of metadata such that
38 /// the rustc version can't be found to compare with `rustc_version()`.
39 pub const METADATA_VERSION: u8 = 4;
41 /// Metadata header which includes `METADATA_VERSION`.
42 /// To get older versions of rustc to ignore this metadata,
43 /// there are 4 zero bytes at the start, which are treated
44 /// as a length of 0 by old compilers.
46 /// This header is followed by the position of the `CrateRoot`,
47 /// which is encoded as a 32-bit big-endian unsigned integer,
48 /// and further followed by the rustc version string.
49 pub const METADATA_HEADER: &'static [u8; 12] =
50 &[0, 0, 0, 0, b'r', b'u', b's', b't', 0, 0, 0, METADATA_VERSION];
52 /// The shorthand encoding uses an enum's variant index `usize`
53 /// and is offset by this value so it never matches a real variant.
54 /// This offset is also chosen so that the first byte is never < 0x80.
55 pub const SHORTHAND_OFFSET: usize = 0x80;
57 /// A value of type T referred to by its absolute position
58 /// in the metadata, and which can be decoded lazily.
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.
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.
75 _marker: PhantomData<T>,
79 pub fn with_position(position: usize) -> Lazy<T> {
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 {
93 impl<T> Copy for Lazy<T> {}
94 impl<T> Clone for Lazy<T> {
95 fn clone(&self) -> Self {
100 impl<T> serialize::UseSpecializedEncodable for Lazy<T> {}
101 impl<T> serialize::UseSpecializedDecodable for Lazy<T> {}
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`.
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.
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.
116 pub struct LazySeq<T> {
119 _marker: PhantomData<T>,
123 pub fn empty() -> LazySeq<T> {
124 LazySeq::with_position_and_length(0, 0)
127 pub fn with_position_and_length(position: usize, len: usize) -> LazySeq<T> {
131 _marker: PhantomData,
135 /// Returns the minimum encoded size of `length` values of type `T`.
136 pub fn min_size(length: usize) -> usize {
141 impl<T> Copy for LazySeq<T> {}
142 impl<T> Clone for LazySeq<T> {
143 fn clone(&self) -> Self {
148 impl<T> serialize::UseSpecializedEncodable for LazySeq<T> {}
149 impl<T> serialize::UseSpecializedDecodable for LazySeq<T> {}
151 /// Encoding / decoding state for `Lazy` and `LazySeq`.
152 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
154 /// Outside of a metadata node.
157 /// Inside a metadata node, and before any `Lazy` or `LazySeq`.
158 /// The position is that of the node itself.
161 /// Inside a metadata node, with a previous `Lazy` or `LazySeq`.
162 /// The position is a conservative estimate of where that
163 /// previous `Lazy` / `LazySeq` would end (see their comments).
167 #[derive(RustcEncodable, RustcDecodable)]
168 pub struct CrateRoot {
171 pub hash: hir::svh::Svh,
172 pub disambiguator: Symbol,
173 pub panic_strategy: PanicStrategy,
174 pub plugin_registrar_fn: Option<DefIndex>,
175 pub macro_derive_registrar: Option<DefIndex>,
177 pub crate_deps: LazySeq<CrateDep>,
178 pub dylib_dependency_formats: LazySeq<Option<LinkagePreference>>,
179 pub lang_items: LazySeq<(DefIndex, usize)>,
180 pub lang_items_missing: LazySeq<lang_items::LangItem>,
181 pub native_libraries: LazySeq<NativeLibrary>,
182 pub codemap: LazySeq<syntax_pos::FileMap>,
183 pub def_path_table: Lazy<hir::map::definitions::DefPathTable>,
184 pub impls: LazySeq<TraitImpls>,
185 pub exported_symbols: LazySeq<DefIndex>,
186 pub index: LazySeq<index::Index>,
189 #[derive(RustcEncodable, RustcDecodable)]
190 pub struct CrateDep {
192 pub hash: hir::svh::Svh,
196 #[derive(RustcEncodable, RustcDecodable)]
197 pub struct TraitImpls {
198 pub trait_id: (u32, DefIndex),
199 pub impls: LazySeq<DefIndex>,
202 #[derive(RustcEncodable, RustcDecodable)]
203 pub struct Entry<'tcx> {
204 pub kind: EntryKind<'tcx>,
205 pub visibility: Lazy<ty::Visibility>,
206 pub span: Lazy<Span>,
207 pub attributes: LazySeq<ast::Attribute>,
208 pub children: LazySeq<DefIndex>,
209 pub stability: Option<Lazy<attr::Stability>>,
210 pub deprecation: Option<Lazy<attr::Deprecation>>,
212 pub ty: Option<Lazy<Ty<'tcx>>>,
213 pub inherent_impls: LazySeq<DefIndex>,
214 pub variances: LazySeq<ty::Variance>,
215 pub generics: Option<Lazy<ty::Generics>>,
216 pub predicates: Option<Lazy<ty::GenericPredicates<'tcx>>>,
218 pub ast: Option<Lazy<astencode::Ast<'tcx>>>,
219 pub mir: Option<Lazy<mir::Mir<'tcx>>>,
222 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
223 pub enum EntryKind<'tcx> {
233 Variant(Lazy<VariantData<'tcx>>),
234 Struct(Lazy<VariantData<'tcx>>, ReprOptions),
235 Union(Lazy<VariantData<'tcx>>, ReprOptions),
237 ForeignFn(Lazy<FnData>),
239 MacroDef(Lazy<MacroDef>),
240 Closure(Lazy<ClosureData<'tcx>>),
241 Trait(Lazy<TraitData<'tcx>>),
242 Impl(Lazy<ImplData<'tcx>>),
243 DefaultImpl(Lazy<ImplData<'tcx>>),
244 Method(Lazy<MethodData>),
245 AssociatedType(AssociatedContainer),
246 AssociatedConst(AssociatedContainer, u8),
249 #[derive(RustcEncodable, RustcDecodable)]
251 pub reexports: LazySeq<def::Export>,
254 #[derive(RustcEncodable, RustcDecodable)]
255 pub struct MacroDef {
259 #[derive(RustcEncodable, RustcDecodable)]
261 pub constness: hir::Constness,
262 pub arg_names: LazySeq<ast::Name>,
265 #[derive(RustcEncodable, RustcDecodable)]
266 pub struct VariantData<'tcx> {
267 pub ctor_kind: CtorKind,
268 pub discr: ty::VariantDiscr,
269 pub evaluated_discr: Option<ConstVal<'tcx>>,
271 /// If this is a struct's only variant, this
272 /// is the index of the "struct ctor" item.
273 pub struct_ctor: Option<DefIndex>,
276 #[derive(RustcEncodable, RustcDecodable)]
277 pub struct TraitData<'tcx> {
278 pub unsafety: hir::Unsafety,
279 pub paren_sugar: bool,
280 pub has_default_impl: bool,
281 pub super_predicates: Lazy<ty::GenericPredicates<'tcx>>,
284 #[derive(RustcEncodable, RustcDecodable)]
285 pub struct ImplData<'tcx> {
286 pub polarity: hir::ImplPolarity,
287 pub parent_impl: Option<DefId>,
289 /// This is `Some` only for impls of `CoerceUnsized`.
290 pub coerce_unsized_info: Option<ty::adjustment::CoerceUnsizedInfo>,
291 pub trait_ref: Option<Lazy<ty::TraitRef<'tcx>>>,
294 /// Describes whether the container of an associated item
295 /// is a trait or an impl and whether, in a trait, it has
296 /// a default, or an in impl, whether it's marked "default".
297 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
298 pub enum AssociatedContainer {
305 impl AssociatedContainer {
306 pub fn with_def_id(&self, def_id: DefId) -> ty::AssociatedItemContainer {
308 AssociatedContainer::TraitRequired |
309 AssociatedContainer::TraitWithDefault => ty::TraitContainer(def_id),
311 AssociatedContainer::ImplDefault |
312 AssociatedContainer::ImplFinal => ty::ImplContainer(def_id),
316 pub fn defaultness(&self) -> hir::Defaultness {
318 AssociatedContainer::TraitRequired => hir::Defaultness::Default {
322 AssociatedContainer::TraitWithDefault |
323 AssociatedContainer::ImplDefault => hir::Defaultness::Default {
327 AssociatedContainer::ImplFinal => hir::Defaultness::Final,
332 #[derive(RustcEncodable, RustcDecodable)]
333 pub struct MethodData {
335 pub container: AssociatedContainer,
339 #[derive(RustcEncodable, RustcDecodable)]
340 pub struct ClosureData<'tcx> {
341 pub kind: ty::ClosureKind,
342 pub ty: Lazy<ty::PolyFnSig<'tcx>>,