Better handling of lib defaults

src/librustc/session/config.rs

@@ -288,7 +288,7 @@ top_level_options!(
         //            much sense: The search path can stay the same while the
         //            things discovered there might have changed on disk.
         search_paths: SearchPaths [TRACKED],
-        libs: Vec<(String, Option<String>, cstore::NativeLibraryKind)> [TRACKED],
+        libs: Vec<(String, Option<String>, Option<cstore::NativeLibraryKind>)> [TRACKED],
         maybe_sysroot: Option<PathBuf> [TRACKED],
 
         target_triple: String [TRACKED],
@@ -1495,18 +1495,18 @@ pub fn build_session_options_and_crate_config(matches: &getopts::Matches)
         let mut parts = s.splitn(2, '=');
         let kind = parts.next().unwrap();
         let (name, kind) = match (parts.next(), kind) {
-            (None, name) |
-            (Some(name), "dylib") => (name, cstore::NativeUnknown),
-            (Some(name), "framework") => (name, cstore::NativeFramework),
-            (Some(name), "static") => (name, cstore::NativeStatic),
-            (Some(name), "static-nobundle") => (name, cstore::NativeStaticNobundle),
+            (None, name) => (name, None),
+            (Some(name), "dylib") => (name, Some(cstore::NativeUnknown)),
+            (Some(name), "framework") => (name, Some(cstore::NativeFramework)),
+            (Some(name), "static") => (name, Some(cstore::NativeStatic)),
+            (Some(name), "static-nobundle") => (name, Some(cstore::NativeStaticNobundle)),
             (_, s) => {
                 early_error(error_format, &format!("unknown library kind `{}`, expected \
                                                   one of dylib, framework, or static",
                                                  s));
             }
         };
-        if kind == cstore::NativeStaticNobundle && !nightly_options::is_nightly_build() {
+        if kind == Some(cstore::NativeStaticNobundle) && !nightly_options::is_nightly_build() {
             early_error(error_format, &format!("the library kind 'static-nobundle' is only \
                                                 accepted on the nightly compiler"));
         }
@@ -1772,6 +1772,7 @@ mod dep_tracking {
     impl_dep_tracking_hash_via_hash!(Option<PanicStrategy>);
     impl_dep_tracking_hash_via_hash!(Option<lint::Level>);
     impl_dep_tracking_hash_via_hash!(Option<PathBuf>);
+    impl_dep_tracking_hash_via_hash!(Option<cstore::NativeLibraryKind>);
     impl_dep_tracking_hash_via_hash!(CrateType);
     impl_dep_tracking_hash_via_hash!(PanicStrategy);
     impl_dep_tracking_hash_via_hash!(Passes);
@@ -1786,7 +1787,7 @@ mod dep_tracking {
     impl_dep_tracking_hash_for_sortable_vec_of!(CrateType);
     impl_dep_tracking_hash_for_sortable_vec_of!((String, lint::Level));
     impl_dep_tracking_hash_for_sortable_vec_of!((String, Option<String>,
-                                                 cstore::NativeLibraryKind));
+                                                 Option<cstore::NativeLibraryKind>));
     impl DepTrackingHash for SearchPaths {
         fn hash(&self, hasher: &mut DefaultHasher, _: ErrorOutputType) {
             let mut elems: Vec<_> = self
@@ -2230,24 +2231,24 @@ mod tests {
         let mut v4 = super::basic_options();
 
         // Reference
-        v1.libs = vec![(String::from("a"), None, cstore::NativeStatic),
-                       (String::from("b"), None, cstore::NativeFramework),
-                       (String::from("c"), None, cstore::NativeUnknown)];
+        v1.libs = vec![(String::from("a"), None, Some(cstore::NativeStatic)),
+                       (String::from("b"), None, Some(cstore::NativeFramework)),
+                       (String::from("c"), None, Some(cstore::NativeUnknown))];
 
         // Change label
-        v2.libs = vec![(String::from("a"), None, cstore::NativeStatic),
-                       (String::from("X"), None, cstore::NativeFramework),
-                       (String::from("c"), None, cstore::NativeUnknown)];
+        v2.libs = vec![(String::from("a"), None, Some(cstore::NativeStatic)),
+                       (String::from("X"), None, Some(cstore::NativeFramework)),
+                       (String::from("c"), None, Some(cstore::NativeUnknown))];
 
         // Change kind
-        v3.libs = vec![(String::from("a"), None, cstore::NativeStatic),
-                       (String::from("b"), None, cstore::NativeStatic),
-                       (String::from("c"), None, cstore::NativeUnknown)];
+        v3.libs = vec![(String::from("a"), None, Some(cstore::NativeStatic)),
+                       (String::from("b"), None, Some(cstore::NativeStatic)),
+                       (String::from("c"), None, Some(cstore::NativeUnknown))];
 
         // Change new-name
-        v4.libs = vec![(String::from("a"), None, cstore::NativeStatic),
-                       (String::from("b"), Some(String::from("X")), cstore::NativeFramework),
-                       (String::from("c"), None, cstore::NativeUnknown)];
+        v4.libs = vec![(String::from("a"), None, Some(cstore::NativeStatic)),
+                       (String::from("b"), Some(String::from("X")), Some(cstore::NativeFramework)),
+                       (String::from("c"), None, Some(cstore::NativeUnknown))];
 
         assert!(v1.dep_tracking_hash() != v2.dep_tracking_hash());
         assert!(v1.dep_tracking_hash() != v3.dep_tracking_hash());
@@ -2267,17 +2268,17 @@ mod tests {
         let mut v3 = super::basic_options();
 
         // Reference
-        v1.libs = vec![(String::from("a"), None, cstore::NativeStatic),
-                       (String::from("b"), None, cstore::NativeFramework),
-                       (String::from("c"), None, cstore::NativeUnknown)];
+        v1.libs = vec![(String::from("a"), None, Some(cstore::NativeStatic)),
+                       (String::from("b"), None, Some(cstore::NativeFramework)),
+                       (String::from("c"), None, Some(cstore::NativeUnknown))];
 
-        v2.libs = vec![(String::from("b"), None, cstore::NativeFramework),
-                       (String::from("a"), None, cstore::NativeStatic),
-                       (String::from("c"), None, cstore::NativeUnknown)];
+        v2.libs = vec![(String::from("b"), None, Some(cstore::NativeFramework)),
+                       (String::from("a"), None, Some(cstore::NativeStatic)),
+                       (String::from("c"), None, Some(cstore::NativeUnknown))];
 
-        v3.libs = vec![(String::from("c"), None, cstore::NativeUnknown),
-                       (String::from("a"), None, cstore::NativeStatic),
-                       (String::from("b"), None, cstore::NativeFramework)];
+        v3.libs = vec![(String::from("c"), None, Some(cstore::NativeUnknown)),
+                       (String::from("a"), None, Some(cstore::NativeStatic)),
+                       (String::from("b"), None, Some(cstore::NativeFramework))];
 
         assert!(v1.dep_tracking_hash() == v2.dep_tracking_hash());
         assert!(v1.dep_tracking_hash() == v3.dep_tracking_hash());

src/librustc_metadata/creader.rs

@@ -1077,10 +1077,20 @@ impl<'a> middle::cstore::CrateLoader for CrateLoader<'a> {
             let mut found = false;
             for lib in self.cstore.get_used_libraries().borrow_mut().iter_mut() {
                 if lib.name == name as &str {
-                    lib.kind = kind;
+                    let mut changed = false;
+                    if let Some(k) = kind {
+                        lib.kind = k;
+                        changed = true;
+                    }
                     if let &Some(ref new_name) = new_name {
                         lib.name = Symbol::intern(new_name);
+                        changed = true;
+                    }
+                    if !changed {
+                        self.sess.warn(&format!("redundant linker flag specified for library `{}`",
+                                                name));
                     }
+
                     found = true;
                 }
             }
@@ -1089,7 +1099,7 @@ impl<'a> middle::cstore::CrateLoader for CrateLoader<'a> {
                 let new_name = new_name.as_ref().map(|s| &**s); // &Option<String> -> Option<&str>
                 let lib = NativeLibrary {
                     name: Symbol::intern(new_name.unwrap_or(name)),
-                    kind: kind,
+                    kind: if let Some(k) = kind { k } else { cstore::NativeUnknown },
                     cfg: None,
                     foreign_items: Vec::new(),
                 };

src/test/run-pass/auxiliary/clibrary.rs

@@ -0,0 +1,15 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// no-prefer-dynamic
+#![crate_type = "staticlib"]
+
+#[no_mangle]
+pub extern "C" fn foo(x:i32) -> i32 { x }

src/test/run-pass/lib-defaults.rs

@@ -0,0 +1,23 @@
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// aux-build:clibrary.rs
+// compile-flags: -lclibrary
+
+#[link(name = "clibrary", kind = "static")]
+extern "C" {
+    pub fn foo(x:i32) -> i32;
+}
+
+fn main() {
+    unsafe {
+        foo(42);
+    }
+}