compiler/rustc_middle/src/middle/cstore.rs

   1 //! the rustc crate store interface. This also includes types that
   2 //! are *mostly* used as a part of that interface, but these should
   3 //! probably get a better home if someone can find one.
   4
   5 use crate::ty::TyCtxt;
   6
   7 use rustc_ast as ast;
   8 use rustc_ast::expand::allocator::AllocatorKind;
   9 use rustc_data_structures::svh::Svh;
  10 use rustc_data_structures::sync::{self, MetadataRef};
  11 use rustc_hir::def::DefKind;
  12 use rustc_hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
  13 use rustc_hir::definitions::{DefKey, DefPath, DefPathHash};
  14 use rustc_macros::HashStable;
  15 use rustc_session::search_paths::PathKind;
  16 use rustc_session::utils::NativeLibKind;
  17 use rustc_session::CrateDisambiguator;
  18 use rustc_span::symbol::Symbol;
  19 use rustc_span::Span;
  20 use rustc_target::spec::Target;
  21
  22 use std::any::Any;
  23 use std::path::{Path, PathBuf};
  24
  25 // lonely orphan structs and enums looking for a better home
  26
  27 /// Where a crate came from on the local filesystem. One of these three options
  28 /// must be non-None.
  29 #[derive(PartialEq, Clone, Debug, HashStable, Encodable, Decodable)]
  30 pub struct CrateSource {
  31     pub dylib: Option<(PathBuf, PathKind)>,
  32     pub rlib: Option<(PathBuf, PathKind)>,
  33     pub rmeta: Option<(PathBuf, PathKind)>,
  34 }
  35
  36 impl CrateSource {
  37     pub fn paths(&self) -> impl Iterator<Item = &PathBuf> {
  38         self.dylib.iter().chain(self.rlib.iter()).chain(self.rmeta.iter()).map(|p| &p.0)
  39     }
  40 }
  41
  42 #[derive(Encodable, Decodable, Copy, Clone, Ord, PartialOrd, Eq, PartialEq, Debug)]
  43 #[derive(HashStable)]
  44 pub enum CrateDepKind {
  45     /// A dependency that is only used for its macros.
  46     MacrosOnly,
  47     /// A dependency that is always injected into the dependency list and so
  48     /// doesn't need to be linked to an rlib, e.g., the injected allocator.
  49     Implicit,
  50     /// A dependency that is required by an rlib version of this crate.
  51     /// Ordinary `extern crate`s result in `Explicit` dependencies.
  52     Explicit,
  53 }
  54
  55 impl CrateDepKind {
  56     pub fn macros_only(self) -> bool {
  57         match self {
  58             CrateDepKind::MacrosOnly => true,
  59             CrateDepKind::Implicit | CrateDepKind::Explicit => false,
  60         }
  61     }
  62 }
  63
  64 #[derive(PartialEq, Clone, Debug, Encodable, Decodable)]
  65 pub enum LibSource {
  66     Some(PathBuf),
  67     MetadataOnly,
  68     None,
  69 }
  70
  71 impl LibSource {
  72     pub fn is_some(&self) -> bool {
  73         matches!(self, LibSource::Some(_))
  74     }
  75
  76     pub fn option(&self) -> Option<PathBuf> {
  77         match *self {
  78             LibSource::Some(ref p) => Some(p.clone()),
  79             LibSource::MetadataOnly | LibSource::None => None,
  80         }
  81     }
  82 }
  83
  84 #[derive(Copy, Debug, PartialEq, Clone, Encodable, Decodable, HashStable)]
  85 pub enum LinkagePreference {
  86     RequireDynamic,
  87     RequireStatic,
  88 }
  89
  90 #[derive(Clone, Debug, Encodable, Decodable, HashStable)]
  91 pub struct NativeLib {
  92     pub kind: NativeLibKind,
  93     pub name: Option<Symbol>,
  94     pub cfg: Option<ast::MetaItem>,
  95     pub foreign_module: Option<DefId>,
  96     pub wasm_import_module: Option<Symbol>,
  97 }
  98
  99 #[derive(Clone, TyEncodable, TyDecodable, HashStable)]
 100 pub struct ForeignModule {
 101     pub foreign_items: Vec<DefId>,
 102     pub def_id: DefId,
 103 }
 104
 105 #[derive(Copy, Clone, Debug, HashStable)]
 106 pub struct ExternCrate {
 107     pub src: ExternCrateSource,
 108
 109     /// span of the extern crate that caused this to be loaded
 110     pub span: Span,
 111
 112     /// Number of links to reach the extern;
 113     /// used to select the extern with the shortest path
 114     pub path_len: usize,
 115
 116     /// Crate that depends on this crate
 117     pub dependency_of: CrateNum,
 118 }
 119
 120 impl ExternCrate {
 121     /// If true, then this crate is the crate named by the extern
 122     /// crate referenced above. If false, then this crate is a dep
 123     /// of the crate.
 124     pub fn is_direct(&self) -> bool {
 125         self.dependency_of == LOCAL_CRATE
 126     }
 127
 128     pub fn rank(&self) -> impl PartialOrd {
 129         // Prefer:
 130         // - direct extern crate to indirect
 131         // - shorter paths to longer
 132         (self.is_direct(), !self.path_len)
 133     }
 134 }
 135
 136 #[derive(Copy, Clone, Debug, HashStable)]
 137 pub enum ExternCrateSource {
 138     /// Crate is loaded by `extern crate`.
 139     Extern(
 140         /// def_id of the item in the current crate that caused
 141         /// this crate to be loaded; note that there could be multiple
 142         /// such ids
 143         DefId,
 144     ),
 145     /// Crate is implicitly loaded by a path resolving through extern prelude.
 146     Path,
 147 }
 148
 149 #[derive(Encodable, Decodable)]
 150 pub struct EncodedMetadata {
 151     pub raw_data: Vec<u8>,
 152 }
 153
 154 impl EncodedMetadata {
 155     pub fn new() -> EncodedMetadata {
 156         EncodedMetadata { raw_data: Vec::new() }
 157     }
 158 }
 159
 160 /// The backend's way to give the crate store access to the metadata in a library.
 161 /// Note that it returns the raw metadata bytes stored in the library file, whether
 162 /// it is compressed, uncompressed, some weird mix, etc.
 163 /// rmeta files are backend independent and not handled here.
 164 ///
 165 /// At the time of this writing, there is only one backend and one way to store
 166 /// metadata in library -- this trait just serves to decouple rustc_metadata from
 167 /// the archive reader, which depends on LLVM.
 168 pub trait MetadataLoader {
 169     fn get_rlib_metadata(&self, target: &Target, filename: &Path) -> Result<MetadataRef, String>;
 170     fn get_dylib_metadata(&self, target: &Target, filename: &Path) -> Result<MetadataRef, String>;
 171 }
 172
 173 pub type MetadataLoaderDyn = dyn MetadataLoader + Sync;
 174
 175 /// A store of Rust crates, through which their metadata can be accessed.
 176 ///
 177 /// Note that this trait should probably not be expanding today. All new
 178 /// functionality should be driven through queries instead!
 179 ///
 180 /// If you find a method on this trait named `{name}_untracked` it signifies
 181 /// that it's *not* tracked for dependency information throughout compilation
 182 /// (it'd break incremental compilation) and should only be called pre-HIR (e.g.
 183 /// during resolve)
 184 pub trait CrateStore {
 185     fn as_any(&self) -> &dyn Any;
 186
 187     // resolve
 188     fn def_key(&self, def: DefId) -> DefKey;
 189     fn def_kind(&self, def: DefId) -> DefKind;
 190     fn def_path(&self, def: DefId) -> DefPath;
 191     fn def_path_hash(&self, def: DefId) -> DefPathHash;
 192     fn def_path_hash_to_def_id(
 193         &self,
 194         cnum: CrateNum,
 195         index_guess: u32,
 196         hash: DefPathHash,
 197     ) -> Option<DefId>;
 198
 199     // "queries" used in resolve that aren't tracked for incremental compilation
 200     fn crate_name_untracked(&self, cnum: CrateNum) -> Symbol;
 201     fn crate_is_private_dep_untracked(&self, cnum: CrateNum) -> bool;
 202     fn crate_disambiguator_untracked(&self, cnum: CrateNum) -> CrateDisambiguator;
 203     fn crate_hash_untracked(&self, cnum: CrateNum) -> Svh;
 204
 205     // This is basically a 1-based range of ints, which is a little
 206     // silly - I may fix that.
 207     fn crates_untracked(&self) -> Vec<CrateNum>;
 208
 209     // utility functions
 210     fn encode_metadata(&self, tcx: TyCtxt<'_>) -> EncodedMetadata;
 211     fn metadata_encoding_version(&self) -> &[u8];
 212     fn allocator_kind(&self) -> Option<AllocatorKind>;
 213 }
 214
 215 pub type CrateStoreDyn = dyn CrateStore + sync::Sync;
 216
 217 // This method is used when generating the command line to pass through to
 218 // system linker. The linker expects undefined symbols on the left of the
 219 // command line to be defined in libraries on the right, not the other way
 220 // around. For more info, see some comments in the add_used_library function
 221 // below.
 222 //
 223 // In order to get this left-to-right dependency ordering, we perform a
 224 // topological sort of all crates putting the leaves at the right-most
 225 // positions.
 226 pub fn used_crates(tcx: TyCtxt<'_>, prefer: LinkagePreference) -> Vec<(CrateNum, LibSource)> {
 227     let mut libs = tcx
 228         .crates()
 229         .iter()
 230         .cloned()
 231         .filter_map(|cnum| {
 232             if tcx.dep_kind(cnum).macros_only() {
 233                 return None;
 234             }
 235             let source = tcx.used_crate_source(cnum);
 236             let path = match prefer {
 237                 LinkagePreference::RequireDynamic => source.dylib.clone().map(|p| p.0),
 238                 LinkagePreference::RequireStatic => source.rlib.clone().map(|p| p.0),
 239             };
 240             let path = match path {
 241                 Some(p) => LibSource::Some(p),
 242                 None => {
 243                     if source.rmeta.is_some() {
 244                         LibSource::MetadataOnly
 245                     } else {
 246                         LibSource::None
 247                     }
 248                 }
 249             };
 250             Some((cnum, path))
 251         })
 252         .collect::<Vec<_>>();
 253     let mut ordering = tcx.postorder_cnums(LOCAL_CRATE).to_owned();
 254     ordering.reverse();
 255     libs.sort_by_cached_key(|&(a, _)| ordering.iter().position(|x| *x == a));
 256     libs
 257 }