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     pub verbatim: Option<bool>,
  98     pub dll_imports: Vec<DllImport>,
  99 }
 100
 101 #[derive(Clone, Debug, Encodable, Decodable, HashStable)]
 102 pub struct DllImport {
 103     pub name: Symbol,
 104     pub ordinal: Option<u16>,
 105 }
 106
 107 #[derive(Clone, TyEncodable, TyDecodable, HashStable, Debug)]
 108 pub struct ForeignModule {
 109     pub foreign_items: Vec<DefId>,
 110     pub def_id: DefId,
 111 }
 112
 113 #[derive(Copy, Clone, Debug, HashStable)]
 114 pub struct ExternCrate {
 115     pub src: ExternCrateSource,
 116
 117     /// span of the extern crate that caused this to be loaded
 118     pub span: Span,
 119
 120     /// Number of links to reach the extern;
 121     /// used to select the extern with the shortest path
 122     pub path_len: usize,
 123
 124     /// Crate that depends on this crate
 125     pub dependency_of: CrateNum,
 126 }
 127
 128 impl ExternCrate {
 129     /// If true, then this crate is the crate named by the extern
 130     /// crate referenced above. If false, then this crate is a dep
 131     /// of the crate.
 132     pub fn is_direct(&self) -> bool {
 133         self.dependency_of == LOCAL_CRATE
 134     }
 135
 136     pub fn rank(&self) -> impl PartialOrd {
 137         // Prefer:
 138         // - direct extern crate to indirect
 139         // - shorter paths to longer
 140         (self.is_direct(), !self.path_len)
 141     }
 142 }
 143
 144 #[derive(Copy, Clone, Debug, HashStable)]
 145 pub enum ExternCrateSource {
 146     /// Crate is loaded by `extern crate`.
 147     Extern(
 148         /// def_id of the item in the current crate that caused
 149         /// this crate to be loaded; note that there could be multiple
 150         /// such ids
 151         DefId,
 152     ),
 153     /// Crate is implicitly loaded by a path resolving through extern prelude.
 154     Path,
 155 }
 156
 157 #[derive(Encodable, Decodable)]
 158 pub struct EncodedMetadata {
 159     pub raw_data: Vec<u8>,
 160 }
 161
 162 impl EncodedMetadata {
 163     pub fn new() -> EncodedMetadata {
 164         EncodedMetadata { raw_data: Vec::new() }
 165     }
 166 }
 167
 168 /// The backend's way to give the crate store access to the metadata in a library.
 169 /// Note that it returns the raw metadata bytes stored in the library file, whether
 170 /// it is compressed, uncompressed, some weird mix, etc.
 171 /// rmeta files are backend independent and not handled here.
 172 ///
 173 /// At the time of this writing, there is only one backend and one way to store
 174 /// metadata in library -- this trait just serves to decouple rustc_metadata from
 175 /// the archive reader, which depends on LLVM.
 176 pub trait MetadataLoader {
 177     fn get_rlib_metadata(&self, target: &Target, filename: &Path) -> Result<MetadataRef, String>;
 178     fn get_dylib_metadata(&self, target: &Target, filename: &Path) -> Result<MetadataRef, String>;
 179 }
 180
 181 pub type MetadataLoaderDyn = dyn MetadataLoader + Sync;
 182
 183 /// A store of Rust crates, through which their metadata can be accessed.
 184 ///
 185 /// Note that this trait should probably not be expanding today. All new
 186 /// functionality should be driven through queries instead!
 187 ///
 188 /// If you find a method on this trait named `{name}_untracked` it signifies
 189 /// that it's *not* tracked for dependency information throughout compilation
 190 /// (it'd break incremental compilation) and should only be called pre-HIR (e.g.
 191 /// during resolve)
 192 pub trait CrateStore {
 193     fn as_any(&self) -> &dyn Any;
 194
 195     // resolve
 196     fn def_key(&self, def: DefId) -> DefKey;
 197     fn def_kind(&self, def: DefId) -> DefKind;
 198     fn def_path(&self, def: DefId) -> DefPath;
 199     fn def_path_hash(&self, def: DefId) -> DefPathHash;
 200     fn def_path_hash_to_def_id(
 201         &self,
 202         cnum: CrateNum,
 203         index_guess: u32,
 204         hash: DefPathHash,
 205     ) -> Option<DefId>;
 206
 207     // "queries" used in resolve that aren't tracked for incremental compilation
 208     fn crate_name_untracked(&self, cnum: CrateNum) -> Symbol;
 209     fn crate_disambiguator_untracked(&self, cnum: CrateNum) -> CrateDisambiguator;
 210     fn crate_hash_untracked(&self, cnum: CrateNum) -> Svh;
 211
 212     // This is basically a 1-based range of ints, which is a little
 213     // silly - I may fix that.
 214     fn crates_untracked(&self) -> Vec<CrateNum>;
 215
 216     // utility functions
 217     fn encode_metadata(&self, tcx: TyCtxt<'_>) -> EncodedMetadata;
 218     fn allocator_kind(&self) -> Option<AllocatorKind>;
 219 }
 220
 221 pub type CrateStoreDyn = dyn CrateStore + sync::Sync;
 222
 223 // This method is used when generating the command line to pass through to
 224 // system linker. The linker expects undefined symbols on the left of the
 225 // command line to be defined in libraries on the right, not the other way
 226 // around. For more info, see some comments in the add_used_library function
 227 // below.
 228 //
 229 // In order to get this left-to-right dependency ordering, we perform a
 230 // topological sort of all crates putting the leaves at the right-most
 231 // positions.
 232 pub fn used_crates(tcx: TyCtxt<'_>, prefer: LinkagePreference) -> Vec<(CrateNum, LibSource)> {
 233     let mut libs = tcx
 234         .crates()
 235         .iter()
 236         .cloned()
 237         .filter_map(|cnum| {
 238             if tcx.dep_kind(cnum).macros_only() {
 239                 return None;
 240             }
 241             let source = tcx.used_crate_source(cnum);
 242             let path = match prefer {
 243                 LinkagePreference::RequireDynamic => source.dylib.clone().map(|p| p.0),
 244                 LinkagePreference::RequireStatic => source.rlib.clone().map(|p| p.0),
 245             };
 246             let path = match path {
 247                 Some(p) => LibSource::Some(p),
 248                 None => {
 249                     if source.rmeta.is_some() {
 250                         LibSource::MetadataOnly
 251                     } else {
 252                         LibSource::None
 253                     }
 254                 }
 255             };
 256             Some((cnum, path))
 257         })
 258         .collect::<Vec<_>>();
 259     let mut ordering = tcx.postorder_cnums(()).to_owned();
 260     ordering.reverse();
 261     libs.sort_by_cached_key(|&(a, _)| ordering.iter().position(|x| *x == a));
 262     libs
 263 }