src/librustc/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::hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
   6 use crate::hir::map as hir_map;
   7 use crate::hir::map::definitions::{DefKey, DefPathTable};
   8 use rustc_data_structures::svh::Svh;
   9 use crate::ty::{self, TyCtxt};
  10 use crate::session::{Session, CrateDisambiguator};
  11 use crate::session::search_paths::PathKind;
  12
  13 use std::any::Any;
  14 use std::path::{Path, PathBuf};
  15 use syntax::ast;
  16 use syntax::symbol::Symbol;
  17 use syntax_pos::Span;
  18 use syntax::expand::allocator::AllocatorKind;
  19 use rustc_target::spec::Target;
  20 use rustc_data_structures::sync::{self, MetadataRef};
  21 use rustc_macros::HashStable;
  22
  23 pub use rustc_session::utils::NativeLibraryKind;
  24 pub use self::NativeLibraryKind::*;
  25
  26 // lonely orphan structs and enums looking for a better home
  27
  28 /// Where a crate came from on the local filesystem. One of these three options
  29 /// must be non-None.
  30 #[derive(PartialEq, Clone, Debug, HashStable)]
  31 pub struct CrateSource {
  32     pub dylib: Option<(PathBuf, PathKind)>,
  33     pub rlib: Option<(PathBuf, PathKind)>,
  34     pub rmeta: Option<(PathBuf, PathKind)>,
  35 }
  36
  37 impl CrateSource {
  38     pub fn paths(&self) -> impl Iterator<Item = &PathBuf> {
  39         self.dylib.iter().chain(self.rlib.iter()).chain(self.rmeta.iter()).map(|p| &p.0)
  40     }
  41 }
  42
  43 #[derive(RustcEncodable, RustcDecodable, Copy, Clone,
  44          Ord, PartialOrd, Eq, PartialEq, Debug, HashStable)]
  45 pub enum DepKind {
  46     /// A dependency that is only used for its macros, none of which are visible from other crates.
  47     /// These are included in the metadata only as placeholders and are ignored when decoding.
  48     UnexportedMacrosOnly,
  49     /// A dependency that is only used for its macros.
  50     MacrosOnly,
  51     /// A dependency that is always injected into the dependency list and so
  52     /// doesn't need to be linked to an rlib, e.g., the injected allocator.
  53     Implicit,
  54     /// A dependency that is required by an rlib version of this crate.
  55     /// Ordinary `extern crate`s result in `Explicit` dependencies.
  56     Explicit,
  57 }
  58
  59 impl DepKind {
  60     pub fn macros_only(self) -> bool {
  61         match self {
  62             DepKind::UnexportedMacrosOnly | DepKind::MacrosOnly => true,
  63             DepKind::Implicit | DepKind::Explicit => false,
  64         }
  65     }
  66 }
  67
  68 #[derive(PartialEq, Clone, Debug)]
  69 pub enum LibSource {
  70     Some(PathBuf),
  71     MetadataOnly,
  72     None,
  73 }
  74
  75 impl LibSource {
  76     pub fn is_some(&self) -> bool {
  77         if let LibSource::Some(_) = *self {
  78             true
  79         } else {
  80             false
  81         }
  82     }
  83
  84     pub fn option(&self) -> Option<PathBuf> {
  85         match *self {
  86             LibSource::Some(ref p) => Some(p.clone()),
  87             LibSource::MetadataOnly | LibSource::None => None,
  88         }
  89     }
  90 }
  91
  92 #[derive(Copy, Debug, PartialEq, Clone, RustcEncodable, RustcDecodable, HashStable)]
  93 pub enum LinkagePreference {
  94     RequireDynamic,
  95     RequireStatic,
  96 }
  97
  98 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
  99 pub struct NativeLibrary {
 100     pub kind: NativeLibraryKind,
 101     pub name: Option<Symbol>,
 102     pub cfg: Option<ast::MetaItem>,
 103     pub foreign_module: Option<DefId>,
 104     pub wasm_import_module: Option<Symbol>,
 105 }
 106
 107 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
 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 pub struct EncodedMetadata {
 158     pub raw_data: Vec<u8>
 159 }
 160
 161 impl EncodedMetadata {
 162     pub fn new() -> EncodedMetadata {
 163         EncodedMetadata {
 164             raw_data: Vec::new(),
 165         }
 166     }
 167 }
 168
 169 /// The backend's way to give the crate store access to the metadata in a library.
 170 /// Note that it returns the raw metadata bytes stored in the library file, whether
 171 /// it is compressed, uncompressed, some weird mix, etc.
 172 /// rmeta files are backend independent and not handled here.
 173 ///
 174 /// At the time of this writing, there is only one backend and one way to store
 175 /// metadata in library -- this trait just serves to decouple rustc_metadata from
 176 /// the archive reader, which depends on LLVM.
 177 pub trait MetadataLoader {
 178     fn get_rlib_metadata(&self,
 179                          target: &Target,
 180                          filename: &Path)
 181                          -> Result<MetadataRef, String>;
 182     fn get_dylib_metadata(&self,
 183                           target: &Target,
 184                           filename: &Path)
 185                           -> Result<MetadataRef, String>;
 186 }
 187
 188 pub type MetadataLoaderDyn = dyn MetadataLoader + Sync;
 189
 190 /// A store of Rust crates, through which their metadata can be accessed.
 191 ///
 192 /// Note that this trait should probably not be expanding today. All new
 193 /// functionality should be driven through queries instead!
 194 ///
 195 /// If you find a method on this trait named `{name}_untracked` it signifies
 196 /// that it's *not* tracked for dependency information throughout compilation
 197 /// (it'd break incremental compilation) and should only be called pre-HIR (e.g.
 198 /// during resolve)
 199 pub trait CrateStore {
 200     fn as_any(&self) -> &dyn Any;
 201
 202     // resolve
 203     fn def_key(&self, def: DefId) -> DefKey;
 204     fn def_path(&self, def: DefId) -> hir_map::DefPath;
 205     fn def_path_hash(&self, def: DefId) -> hir_map::DefPathHash;
 206     fn def_path_table(&self, cnum: CrateNum) -> &DefPathTable;
 207
 208     // "queries" used in resolve that aren't tracked for incremental compilation
 209     fn crate_name_untracked(&self, cnum: CrateNum) -> Symbol;
 210     fn crate_is_private_dep_untracked(&self, cnum: CrateNum) -> bool;
 211     fn crate_disambiguator_untracked(&self, cnum: CrateNum) -> CrateDisambiguator;
 212     fn crate_hash_untracked(&self, cnum: CrateNum) -> Svh;
 213     fn item_generics_cloned_untracked(&self, def: DefId, sess: &Session) -> ty::Generics;
 214
 215     // This is basically a 1-based range of ints, which is a little
 216     // silly - I may fix that.
 217     fn crates_untracked(&self) -> Vec<CrateNum>;
 218
 219     // utility functions
 220     fn encode_metadata(&self, tcx: TyCtxt<'_>) -> EncodedMetadata;
 221     fn metadata_encoding_version(&self) -> &[u8];
 222     fn allocator_kind(&self) -> Option<AllocatorKind>;
 223 }
 224
 225 pub type CrateStoreDyn = dyn CrateStore + sync::Sync;
 226
 227 // This method is used when generating the command line to pass through to
 228 // system linker. The linker expects undefined symbols on the left of the
 229 // command line to be defined in libraries on the right, not the other way
 230 // around. For more info, see some comments in the add_used_library function
 231 // below.
 232 //
 233 // In order to get this left-to-right dependency ordering, we perform a
 234 // topological sort of all crates putting the leaves at the right-most
 235 // positions.
 236 pub fn used_crates(tcx: TyCtxt<'_>, prefer: LinkagePreference) -> Vec<(CrateNum, LibSource)> {
 237     let mut libs = tcx.crates()
 238         .iter()
 239         .cloned()
 240         .filter_map(|cnum| {
 241             if tcx.dep_kind(cnum).macros_only() {
 242                 return None
 243             }
 244             let source = tcx.used_crate_source(cnum);
 245             let path = match prefer {
 246                 LinkagePreference::RequireDynamic => source.dylib.clone().map(|p| p.0),
 247                 LinkagePreference::RequireStatic => source.rlib.clone().map(|p| p.0),
 248             };
 249             let path = match path {
 250                 Some(p) => LibSource::Some(p),
 251                 None => {
 252                     if source.rmeta.is_some() {
 253                         LibSource::MetadataOnly
 254                     } else {
 255                         LibSource::None
 256                     }
 257                 }
 258             };
 259             Some((cnum, path))
 260         })
 261         .collect::<Vec<_>>();
 262     let mut ordering = tcx.postorder_cnums(LOCAL_CRATE).to_owned();
 263     ordering.reverse();
 264     libs.sort_by_cached_key(|&(a, _)| {
 265         ordering.iter().position(|x| *x == a)
 266     });
 267     libs
 268 }