Auto merge of #37681 - nrc:crate-metadata, r=@alexcrichton

add --crate-type metadata

r? @alexcrichton

src/librustc/middle/cstore.rs

@@ -56,12 +56,13 @@ pub struct LinkMeta {
     pub crate_hash: Svh,
 }
 
-// Where a crate came from on the local filesystem. One of these two options
+// Where a crate came from on the local filesystem. One of these three options
 // must be non-None.
 #[derive(PartialEq, Clone, Debug)]
 pub struct CrateSource {
     pub dylib: Option<(PathBuf, PathKind)>,
     pub rlib: Option<(PathBuf, PathKind)>,
+    pub rmeta: Option<(PathBuf, PathKind)>,
 }
 
 #[derive(RustcEncodable, RustcDecodable, Copy, Clone, Ord, PartialOrd, Eq, PartialEq, Debug)]
@@ -76,6 +77,30 @@ pub enum DepKind {
     Explicit,
 }
 
+#[derive(PartialEq, Clone, Debug)]
+pub enum LibSource {
+    Some(PathBuf),
+    MetadataOnly,
+    None,
+}
+
+impl LibSource {
+    pub fn is_some(&self) -> bool {
+        if let LibSource::Some(_) = *self {
+            true
+        } else {
+            false
+        }
+    }
+
+    pub fn option(&self) -> Option<PathBuf> {
+        match *self {
+            LibSource::Some(ref p) => Some(p.clone()),
+            LibSource::MetadataOnly | LibSource::None => None,
+        }
+    }
+}
+
 #[derive(Copy, Debug, PartialEq, Clone, RustcEncodable, RustcDecodable)]
 pub enum LinkagePreference {
     RequireDynamic,
@@ -244,7 +269,7 @@ pub trait CrateStore<'tcx> {
     // utility functions
     fn metadata_filename(&self) -> &str;
     fn metadata_section_name(&self, target: &Target) -> &str;
-    fn used_crates(&self, prefer: LinkagePreference) -> Vec<(CrateNum, Option<PathBuf>)>;
+    fn used_crates(&self, prefer: LinkagePreference) -> Vec<(CrateNum, LibSource)>;
     fn used_crate_source(&self, cnum: CrateNum) -> CrateSource;
     fn extern_mod_stmt_cnum(&self, emod_id: ast::NodeId) -> Option<CrateNum>;
     fn encode_metadata<'a>(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>,
@@ -427,7 +452,7 @@ impl<'tcx> CrateStore<'tcx> for DummyCrateStore {
     // utility functions
     fn metadata_filename(&self) -> &str { bug!("metadata_filename") }
     fn metadata_section_name(&self, target: &Target) -> &str { bug!("metadata_section_name") }
-    fn used_crates(&self, prefer: LinkagePreference) -> Vec<(CrateNum, Option<PathBuf>)>
+    fn used_crates(&self, prefer: LinkagePreference) -> Vec<(CrateNum, LibSource)>
         { vec![] }
     fn used_crate_source(&self, cnum: CrateNum) -> CrateSource { bug!("used_crate_source") }
     fn extern_mod_stmt_cnum(&self, emod_id: ast::NodeId) -> Option<CrateNum> { None }

src/librustc/middle/dependency_format.rs

@@ -114,7 +114,7 @@ fn calculate_type(sess: &session::Session,
 
         // No linkage happens with rlibs, we just needed the metadata (which we
         // got long ago), so don't bother with anything.
-        config::CrateTypeRlib => return Vec::new(),
+        config::CrateTypeRlib | config::CrateTypeMetadata => return Vec::new(),
 
         // Staticlibs and cdylibs must have all static dependencies. If any fail
         // to be found, we generate some nice pretty errors.
@@ -192,7 +192,7 @@ fn calculate_type(sess: &session::Session,
         if src.dylib.is_none() &&
            !formats.contains_key(&cnum) &&
            sess.cstore.dep_kind(cnum) == DepKind::Explicit {
-            assert!(src.rlib.is_some());
+            assert!(src.rlib.is_some() || src.rmeta.is_some());
             info!("adding staticlib: {}", sess.cstore.crate_name(cnum));
             add_library(sess, cnum, RequireStatic, &mut formats);
             ret[cnum.as_usize() - 1] = Linkage::Static;

src/librustc/middle/reachable.rs

@@ -140,7 +140,7 @@ impl<'a, 'tcx> ReachableContext<'a, 'tcx> {
     fn new(tcx: TyCtxt<'a, 'tcx, 'tcx>) -> ReachableContext<'a, 'tcx> {
         let any_library = tcx.sess.crate_types.borrow().iter().any(|ty| {
             *ty == config::CrateTypeRlib || *ty == config::CrateTypeDylib ||
-            *ty == config::CrateTypeProcMacro
+            *ty == config::CrateTypeProcMacro || *ty == config::CrateTypeMetadata
         });
         ReachableContext {
             tcx: tcx,

src/librustc/middle/weak_lang_items.rs

@@ -75,7 +75,8 @@ fn verify(sess: &Session, items: &lang_items::LanguageItems) {
             config::CrateTypeCdylib |
             config::CrateTypeExecutable |
             config::CrateTypeStaticlib => true,
-            config::CrateTypeRlib => false,
+            config::CrateTypeRlib |
+            config::CrateTypeMetadata => false,
         }
     });
     if !needs_check {