Refactor `explicitly_linked: bool` -> `dep_kind: DepKind`.

src/librustc/middle/cstore.rs

@@ -63,6 +63,16 @@ pub struct CrateSource {
     pub rlib: Option<(PathBuf, PathKind)>,
 }
 
+#[derive(RustcEncodable, RustcDecodable, Copy, Clone, Ord, PartialOrd, Eq, PartialEq, Debug)]
+pub enum DepKind {
+    /// A dependency that is always injected into the dependency list and so
+    /// doesn't need to be linked to an rlib, e.g. the injected allocator.
+    Implicit,
+    /// A dependency that is required by an rlib version of this crate.
+    /// Ordinary `extern crate`s result in `Explicit` dependencies.
+    Explicit,
+}
+
 #[derive(Copy, Debug, PartialEq, Clone, RustcEncodable, RustcDecodable)]
 pub enum LinkagePreference {
     RequireDynamic,
@@ -169,10 +179,10 @@ fn associated_item<'a>(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>, def: DefId)
     // crate metadata
     fn dylib_dependency_formats(&self, cnum: CrateNum)
                                     -> Vec<(CrateNum, LinkagePreference)>;
+    fn dep_kind(&self, cnum: CrateNum) -> DepKind;
     fn lang_items(&self, cnum: CrateNum) -> Vec<(DefIndex, usize)>;
     fn missing_lang_items(&self, cnum: CrateNum) -> Vec<lang_items::LangItem>;
     fn is_staged_api(&self, cnum: CrateNum) -> bool;
-    fn is_explicitly_linked(&self, cnum: CrateNum) -> bool;
     fn is_allocator(&self, cnum: CrateNum) -> bool;
     fn is_panic_runtime(&self, cnum: CrateNum) -> bool;
     fn is_compiler_builtins(&self, cnum: CrateNum) -> bool;
@@ -341,7 +351,7 @@ fn lang_items(&self, cnum: CrateNum) -> Vec<(DefIndex, usize)>
     fn missing_lang_items(&self, cnum: CrateNum) -> Vec<lang_items::LangItem>
         { bug!("missing_lang_items") }
     fn is_staged_api(&self, cnum: CrateNum) -> bool { bug!("is_staged_api") }
-    fn is_explicitly_linked(&self, cnum: CrateNum) -> bool { bug!("is_explicitly_linked") }
+    fn dep_kind(&self, cnum: CrateNum) -> DepKind { bug!("is_explicitly_linked") }
     fn is_allocator(&self, cnum: CrateNum) -> bool { bug!("is_allocator") }
     fn is_panic_runtime(&self, cnum: CrateNum) -> bool { bug!("is_panic_runtime") }
     fn is_compiler_builtins(&self, cnum: CrateNum) -> bool { bug!("is_compiler_builtins") }

src/librustc/middle/dependency_format.rs

@@ -65,6 +65,7 @@
 
 use session;
 use session::config;
+use middle::cstore::DepKind;
 use middle::cstore::LinkagePreference::{self, RequireStatic, RequireDynamic};
 use util::nodemap::FxHashMap;
 use rustc_back::PanicStrategy;
@@ -188,7 +189,7 @@ fn calculate_type(sess: &session::Session,
         let src = sess.cstore.used_crate_source(cnum);
         if src.dylib.is_none() &&
            !formats.contains_key(&cnum) &&
-           sess.cstore.is_explicitly_linked(cnum) {
+           sess.cstore.dep_kind(cnum) == DepKind::Explicit {
             assert!(src.rlib.is_some());
             info!("adding staticlib: {}", sess.cstore.crate_name(cnum));
             add_library(sess, cnum, RequireStatic, &mut formats);
@@ -272,7 +273,7 @@ fn attempt_static(sess: &session::Session) -> Option<DependencyList> {
     // everything in explicitly so long as it's actually required.
     let last_crate = sess.cstore.crates().len();
     let mut ret = (1..last_crate+1).map(|cnum| {
-        if sess.cstore.is_explicitly_linked(CrateNum::new(cnum)) {
+        if sess.cstore.dep_kind(CrateNum::new(cnum)) == DepKind::Explicit {
             Linkage::Static
         } else {
             Linkage::NotLinked

src/librustc_metadata/creader.rs

@@ -16,7 +16,7 @@
 
 use rustc::hir::def_id::{CrateNum, DefIndex};
 use rustc::hir::svh::Svh;
-use rustc::middle::cstore::LoadedMacros;
+use rustc::middle::cstore::{DepKind, LoadedMacros};
 use rustc::session::{config, Session};
 use rustc_back::PanicStrategy;
 use rustc::session::search_paths::PathKind;
@@ -29,7 +29,7 @@
 use std::ops::Deref;
 use std::path::PathBuf;
 use std::rc::Rc;
-use std::fs;
+use std::{cmp, fs};
 
 use syntax::ast;
 use syntax::abi::Abi;
@@ -60,7 +60,7 @@ fn dump_crates(cstore: &CStore) {
         info!("  name: {}", data.name());
         info!("  cnum: {}", data.cnum);
         info!("  hash: {}", data.hash());
-        info!("  reqd: {}", data.explicitly_linked.get());
+        info!("  reqd: {:?}", data.dep_kind.get());
         let CrateSource { dylib, rlib } = data.source.clone();
         dylib.map(|dl| info!("  dylib: {}", dl.0.display()));
         rlib.map(|rl|  info!("   rlib: {}", rl.0.display()));
@@ -258,7 +258,7 @@ fn register_crate(&mut self,
                       name: &str,
                       span: Span,
                       lib: Library,
-                      explicitly_linked: bool)
+                      dep_kind: DepKind)
                       -> (CrateNum, Rc<cstore::CrateMetadata>) {
         info!("register crate `extern crate {} as {}`", name, ident);
         let crate_root = lib.metadata.get_root();
@@ -299,7 +299,7 @@ fn register_crate(&mut self,
             cnum_map: RefCell::new(cnum_map),
             cnum: cnum,
             codemap_import_info: RefCell::new(vec![]),
-            explicitly_linked: Cell::new(explicitly_linked),
+            dep_kind: Cell::new(dep_kind),
             source: cstore::CrateSource {
                 dylib: dylib,
                 rlib: rlib,
@@ -317,7 +317,7 @@ fn resolve_crate(&mut self,
                      hash: Option<&Svh>,
                      span: Span,
                      kind: PathKind,
-                     explicitly_linked: bool)
+                     dep_kind: DepKind)
                      -> (CrateNum, Rc<cstore::CrateMetadata>) {
         info!("resolving crate `extern crate {} as {}`", name, ident);
         let result = match self.existing_match(name, hash, kind) {
@@ -350,12 +350,11 @@ fn resolve_crate(&mut self,
         match result {
             LoadResult::Previous(cnum) => {
                 let data = self.cstore.get_crate_data(cnum);
-                data.explicitly_linked.set(explicitly_linked || data.explicitly_linked.get());
+                data.dep_kind.set(cmp::max(data.dep_kind.get(), dep_kind));
                 (cnum, data)
             }
             LoadResult::Loaded(library) => {
-                self.register_crate(root, ident, name, span, library,
-                                    explicitly_linked)
+                self.register_crate(root, ident, name, span, library, dep_kind)
             }
         }
     }
@@ -442,7 +441,7 @@ fn resolve_crate_deps(&mut self,
                                                         Some(&dep.hash),
                                                         span,
                                                         PathKind::Dependency,
-                                                        dep.explicitly_linked);
+                                                        dep.kind);
             (CrateNum::new(crate_num + 1), local_cnum)
         }).collect();
 
@@ -716,7 +715,7 @@ fn inject_panic_runtime(&mut self, krate: &ast::Crate) {
                 // #![panic_runtime] crate.
                 self.inject_dependency_if(cnum, "a panic runtime",
                                           &|data| data.needs_panic_runtime());
-                runtime_found = runtime_found || data.explicitly_linked.get();
+                runtime_found = runtime_found || data.dep_kind.get() == DepKind::Explicit;
             }
         });
 
@@ -745,8 +744,9 @@ fn inject_panic_runtime(&mut self, krate: &ast::Crate) {
         };
         info!("panic runtime not found -- loading {}", name);
 
+        let dep_kind = DepKind::Implicit;
         let (cnum, data) =
-            self.resolve_crate(&None, name, name, None, DUMMY_SP, PathKind::Crate, false);
+            self.resolve_crate(&None, name, name, None, DUMMY_SP, PathKind::Crate, dep_kind);
 
         // Sanity check the loaded crate to ensure it is indeed a panic runtime
         // and the panic strategy is indeed what we thought it was.
@@ -780,7 +780,7 @@ fn inject_allocator_crate(&mut self) {
                 self.inject_dependency_if(cnum, "an allocator",
                                           &|data| data.needs_allocator());
                 found_required_allocator = found_required_allocator ||
-                    data.explicitly_linked.get();
+                    data.dep_kind.get() == DepKind::Explicit;
             }
         });
         if !needs_allocator || found_required_allocator { return }
@@ -826,8 +826,9 @@ fn inject_allocator_crate(&mut self) {
         } else {
             &self.sess.target.target.options.exe_allocation_crate
         };
+        let dep_kind = DepKind::Implicit;
         let (cnum, data) =
-            self.resolve_crate(&None, name, name, None, DUMMY_SP, PathKind::Crate, false);
+            self.resolve_crate(&None, name, name, None, DUMMY_SP, PathKind::Crate, dep_kind);
 
         // Sanity check the crate we loaded to ensure that it is indeed an
         // allocator.
@@ -993,7 +994,7 @@ fn process_item(&mut self, item: &ast::Item, definitions: &Definitions, load_mac
             if let PMDSource::Owned(lib) = ekrate.metadata {
                 if ekrate.target_only || config::host_triple() == self.sess.opts.target_triple {
                     let ExternCrateInfo { ref ident, ref name, .. } = info;
-                    self.register_crate(&None, ident, name, item.span, lib, true);
+                    self.register_crate(&None, ident, name, item.span, lib, DepKind::Explicit);
                 }
             }
 
@@ -1006,7 +1007,7 @@ fn process_item(&mut self, item: &ast::Item, definitions: &Definitions, load_mac
         };
 
         let (cnum, ..) = self.resolve_crate(
-            &None, &info.ident, &info.name, None, item.span, PathKind::Crate, true,
+            &None, &info.ident, &info.name, None, item.span, PathKind::Crate, DepKind::Explicit,
         );
 
         let def_id = definitions.opt_local_def_id(item.id).unwrap();

src/librustc_metadata/cstore.rs

@@ -18,7 +18,7 @@
 use rustc::hir::def_id::{CRATE_DEF_INDEX, CrateNum, DefIndex, DefId};
 use rustc::hir::map::DefKey;
 use rustc::hir::svh::Svh;
-use rustc::middle::cstore::ExternCrate;
+use rustc::middle::cstore::{DepKind, ExternCrate};
 use rustc_back::PanicStrategy;
 use rustc_data_structures::indexed_vec::IndexVec;
 use rustc::util::nodemap::{FxHashMap, NodeMap, NodeSet, DefIdMap};
@@ -78,12 +78,7 @@ pub struct CrateMetadata {
     /// compilation support.
     pub key_map: FxHashMap<DefKey, DefIndex>,
 
-    /// Flag if this crate is required by an rlib version of this crate, or in
-    /// other words whether it was explicitly linked to. An example of a crate
-    /// where this is false is when an allocator crate is injected into the
-    /// dependency list, and therefore isn't actually needed to link an rlib.
-    pub explicitly_linked: Cell<bool>,
-
+    pub dep_kind: Cell<DepKind>,
     pub source: CrateSource,
 }
 

src/librustc_metadata/cstore_impl.rs

@@ -13,7 +13,7 @@
 use locator;
 use schema;
 
-use rustc::middle::cstore::{InlinedItem, CrateStore, CrateSource, ExternCrate};
+use rustc::middle::cstore::{InlinedItem, CrateStore, CrateSource, DepKind, ExternCrate};
 use rustc::middle::cstore::{NativeLibraryKind, LinkMeta, LinkagePreference};
 use rustc::hir::def::{self, Def};
 use rustc::middle::lang_items;
@@ -221,6 +221,11 @@ fn dylib_dependency_formats(&self, cnum: CrateNum)
         self.get_crate_data(cnum).get_dylib_dependency_formats()
     }
 
+    fn dep_kind(&self, cnum: CrateNum) -> DepKind
+    {
+        self.get_crate_data(cnum).dep_kind.get()
+    }
+
     fn lang_items(&self, cnum: CrateNum) -> Vec<(DefIndex, usize)>
     {
         self.get_crate_data(cnum).get_lang_items()
@@ -237,11 +242,6 @@ fn is_staged_api(&self, cnum: CrateNum) -> bool
         self.get_crate_data(cnum).is_staged_api()
     }
 
-    fn is_explicitly_linked(&self, cnum: CrateNum) -> bool
-    {
-        self.get_crate_data(cnum).explicitly_linked.get()
-    }
-
     fn is_allocator(&self, cnum: CrateNum) -> bool
     {
         self.get_crate_data(cnum).is_allocator()

src/librustc_metadata/encoder.rs

@@ -1080,7 +1080,7 @@ fn get_ordered_deps(cstore: &cstore::CStore) -> Vec<(CrateNum, Rc<cstore::CrateM
             CrateDep {
                 name: syntax::parse::token::intern(dep.name()),
                 hash: dep.hash(),
-                explicitly_linked: dep.explicitly_linked.get(),
+                kind: dep.dep_kind.get(),
             }
         }))
     }

src/librustc_metadata/schema.rs

@@ -14,7 +14,7 @@
 use rustc::hir;
 use rustc::hir::def::{self, CtorKind};
 use rustc::hir::def_id::{DefIndex, DefId};
-use rustc::middle::cstore::{LinkagePreference, NativeLibraryKind};
+use rustc::middle::cstore::{DepKind, LinkagePreference, NativeLibraryKind};
 use rustc::middle::lang_items;
 use rustc::mir;
 use rustc::ty::{self, Ty};
@@ -187,7 +187,7 @@ pub struct CrateRoot {
 pub struct CrateDep {
     pub name: ast::Name,
     pub hash: hir::svh::Svh,
-    pub explicitly_linked: bool,
+    pub kind: DepKind,
 }
 
 #[derive(RustcEncodable, RustcDecodable)]