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 rustc_target::spec::Target;
  19 use rustc_data_structures::sync::{self, MetadataRef, Lrc};
  20 use rustc_macros::HashStable;
  21
  22 pub use self::NativeLibraryKind::*;
  23
  24 // lonely orphan structs and enums looking for a better home
  25
  26 /// Where a crate came from on the local filesystem. One of these three options
  27 /// must be non-None.
  28 #[derive(PartialEq, Clone, Debug, HashStable)]
  29 pub struct CrateSource {
  30     pub dylib: Option<(PathBuf, PathKind)>,
  31     pub rlib: Option<(PathBuf, PathKind)>,
  32     pub rmeta: Option<(PathBuf, PathKind)>,
  33 }
  34
  35 #[derive(RustcEncodable, RustcDecodable, Copy, Clone,
  36          Ord, PartialOrd, Eq, PartialEq, Debug, HashStable)]
  37 pub enum DepKind {
  38     /// A dependency that is only used for its macros, none of which are visible from other crates.
  39     /// These are included in the metadata only as placeholders and are ignored when decoding.
  40     UnexportedMacrosOnly,
  41     /// A dependency that is only used for its macros.
  42     MacrosOnly,
  43     /// A dependency that is always injected into the dependency list and so
  44     /// doesn't need to be linked to an rlib, e.g., the injected allocator.
  45     Implicit,
  46     /// A dependency that is required by an rlib version of this crate.
  47     /// Ordinary `extern crate`s result in `Explicit` dependencies.
  48     Explicit,
  49 }
  50
  51 impl DepKind {
  52     pub fn macros_only(self) -> bool {
  53         match self {
  54             DepKind::UnexportedMacrosOnly | DepKind::MacrosOnly => true,
  55             DepKind::Implicit | DepKind::Explicit => false,
  56         }
  57     }
  58 }
  59
  60 #[derive(PartialEq, Clone, Debug)]
  61 pub enum LibSource {
  62     Some(PathBuf),
  63     MetadataOnly,
  64     None,
  65 }
  66
  67 impl LibSource {
  68     pub fn is_some(&self) -> bool {
  69         if let LibSource::Some(_) = *self {
  70             true
  71         } else {
  72             false
  73         }
  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, RustcEncodable, RustcDecodable, HashStable)]
  85 pub enum LinkagePreference {
  86     RequireDynamic,
  87     RequireStatic,
  88 }
  89
  90 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash,
  91          RustcEncodable, RustcDecodable, HashStable)]
  92 pub enum NativeLibraryKind {
  93     /// native static library (.a archive)
  94     NativeStatic,
  95     /// native static library, which doesn't get bundled into .rlibs
  96     NativeStaticNobundle,
  97     /// macOS-specific
  98     NativeFramework,
  99     /// default way to specify a dynamic library
 100     NativeUnknown,
 101 }
 102
 103 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
 104 pub struct NativeLibrary {
 105     pub kind: NativeLibraryKind,
 106     pub name: Option<Symbol>,
 107     pub cfg: Option<ast::MetaItem>,
 108     pub foreign_module: Option<DefId>,
 109     pub wasm_import_module: Option<Symbol>,
 110 }
 111
 112 #[derive(Clone, Hash, RustcEncodable, RustcDecodable, HashStable)]
 113 pub struct ForeignModule {
 114     pub foreign_items: Vec<DefId>,
 115     pub def_id: DefId,
 116 }
 117
 118 #[derive(Copy, Clone, Debug, HashStable)]
 119 pub struct ExternCrate {
 120     pub src: ExternCrateSource,
 121
 122     /// span of the extern crate that caused this to be loaded
 123     pub span: Span,
 124
 125     /// Number of links to reach the extern;
 126     /// used to select the extern with the shortest path
 127     pub path_len: usize,
 128
 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 direct: bool,
 133 }
 134
 135 #[derive(Copy, Clone, Debug, HashStable)]
 136 pub enum ExternCrateSource {
 137     /// Crate is loaded by `extern crate`.
 138     Extern(
 139         /// def_id of the item in the current crate that caused
 140         /// this crate to be loaded; note that there could be multiple
 141         /// such ids
 142         DefId,
 143     ),
 144     // Crate is loaded by `use`.
 145     Use,
 146     /// Crate is implicitly loaded by an absolute path.
 147     Path,
 148 }
 149
 150 pub struct EncodedMetadata {
 151     pub raw_data: Vec<u8>
 152 }
 153
 154 impl EncodedMetadata {
 155     pub fn new() -> EncodedMetadata {
 156         EncodedMetadata {
 157             raw_data: Vec::new(),
 158         }
 159     }
 160 }
 161
 162 /// The backend's way to give the crate store access to the metadata in a library.
 163 /// Note that it returns the raw metadata bytes stored in the library file, whether
 164 /// it is compressed, uncompressed, some weird mix, etc.
 165 /// rmeta files are backend independent and not handled here.
 166 ///
 167 /// At the time of this writing, there is only one backend and one way to store
 168 /// metadata in library -- this trait just serves to decouple rustc_metadata from
 169 /// the archive reader, which depends on LLVM.
 170 pub trait MetadataLoader {
 171     fn get_rlib_metadata(&self,
 172                          target: &Target,
 173                          filename: &Path)
 174                          -> Result<MetadataRef, String>;
 175     fn get_dylib_metadata(&self,
 176                           target: &Target,
 177                           filename: &Path)
 178                           -> Result<MetadataRef, String>;
 179 }
 180
 181 /// A store of Rust crates, through with their metadata
 182 /// can be accessed.
 183 ///
 184 /// Note that this trait should probably not be expanding today. All new
 185 /// functionality should be driven through queries instead!
 186 ///
 187 /// If you find a method on this trait named `{name}_untracked` it signifies
 188 /// that it's *not* tracked for dependency information throughout compilation
 189 /// (it'd break incremental compilation) and should only be called pre-HIR (e.g.
 190 /// during resolve)
 191 pub trait CrateStore {
 192     fn crate_data_as_rc_any(&self, krate: CrateNum) -> Lrc<dyn Any>;
 193
 194     // resolve
 195     fn def_key(&self, def: DefId) -> DefKey;
 196     fn def_path(&self, def: DefId) -> hir_map::DefPath;
 197     fn def_path_hash(&self, def: DefId) -> hir_map::DefPathHash;
 198     fn def_path_table(&self, cnum: CrateNum) -> Lrc<DefPathTable>;
 199
 200     // "queries" used in resolve that aren't tracked for incremental compilation
 201     fn crate_name_untracked(&self, cnum: CrateNum) -> Symbol;
 202     fn crate_is_private_dep_untracked(&self, cnum: CrateNum) -> bool;
 203     fn crate_disambiguator_untracked(&self, cnum: CrateNum) -> CrateDisambiguator;
 204     fn crate_hash_untracked(&self, cnum: CrateNum) -> Svh;
 205     fn extern_mod_stmt_cnum_untracked(&self, emod_id: ast::NodeId) -> Option<CrateNum>;
 206     fn item_generics_cloned_untracked(&self, def: DefId, sess: &Session) -> ty::Generics;
 207     fn postorder_cnums_untracked(&self) -> Vec<CrateNum>;
 208
 209     // This is basically a 1-based range of ints, which is a little
 210     // silly - I may fix that.
 211     fn crates_untracked(&self) -> Vec<CrateNum>;
 212
 213     // utility functions
 214     fn encode_metadata<'a, 'tcx>(&self,
 215                                  tcx: TyCtxt<'a, 'tcx, 'tcx>)
 216                                  -> EncodedMetadata;
 217     fn metadata_encoding_version(&self) -> &[u8];
 218 }
 219
 220 pub type CrateStoreDyn = dyn CrateStore + sync::Sync;
 221
 222 // This method is used when generating the command line to pass through to
 223 // system linker. The linker expects undefined symbols on the left of the
 224 // command line to be defined in libraries on the right, not the other way
 225 // around. For more info, see some comments in the add_used_library function
 226 // below.
 227 //
 228 // In order to get this left-to-right dependency ordering, we perform a
 229 // topological sort of all crates putting the leaves at the right-most
 230 // positions.
 231 pub fn used_crates(tcx: TyCtxt<'_, '_, '_>, prefer: LinkagePreference)
 232     -> Vec<(CrateNum, LibSource)>
 233 {
 234     let mut libs = tcx.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(LOCAL_CRATE);
 260     Lrc::make_mut(&mut ordering).reverse();
 261     libs.sort_by_cached_key(|&(a, _)| {
 262         ordering.iter().position(|x| *x == a)
 263     });
 264     libs
 265 }