Use metadata to avoid always passing -Lrustllvm to the linker.

Author: cixtor

src/comp/driver/rustc.rs

@@ -299,7 +299,7 @@ fn build_session(@session::options sopts) -> session::session {
     auto target_crate_num = 0;
     auto sess =
         session::session(target_crate_num, target_cfg, sopts, crate_cache, [],
-                         [], front::codemap::new_codemap(), 0u);
+                         [], [], front::codemap::new_codemap(), 0u);
     ret sess;
 }
 
@@ -460,7 +460,7 @@ fn main(vec[str] args) {
                 case (_) { rmext(filename) }
             };
         }
-        
+
         for (str cratepath in sess.get_used_crate_files()) {
             auto dir = fs::dirname(cratepath);
             if (dir != "") {
@@ -470,6 +470,7 @@ fn main(vec[str] args) {
             gcc_args += ["-l" + libarg];
         }
 
+        gcc_args += sess.get_used_link_args();
         auto used_libs = sess.get_used_libraries();
         for (str l in used_libs) {
             gcc_args += ["-l" + l];
@@ -478,9 +479,8 @@ fn main(vec[str] args) {
         if (sopts.shared) {
             gcc_args += [shared_cmd];
         } else {
-            // FIXME: having -Lrustllvm hardcoded in here is hack
-            // FIXME: same for -lm
-            gcc_args += ["-Lrustllvm", "-lm", main];
+            // FIXME: why do we hardcode -lm?
+            gcc_args += ["-lm", main];
         }
         // We run 'gcc' here
 

src/comp/driver/session.rs

@@ -10,6 +10,7 @@ import std::map;
 import std::option;
 import std::option::some;
 import std::option::none;
+import std::str;
 
 tag os { os_win32; os_macos; os_linux; }
 
@@ -71,6 +72,7 @@ obj session(ast::crate_num cnum,
             map::hashmap[int, crate_metadata] crates,
             mutable vec[str] used_crate_files,
             mutable vec[str] used_libraries,
+            mutable vec[str] used_link_args,
             codemap::codemap cm,
             mutable uint err_count) {
     fn get_targ_cfg() -> @config { ret targ_cfg; }
@@ -130,18 +132,25 @@ obj session(ast::crate_num cnum,
         crates.insert(num, metadata);
     }
     fn has_external_crate(int num) -> bool { ret crates.contains_key(num); }
-    fn add_used_library(&str lib) {
+    fn add_used_link_args(&str args) {
+        used_link_args += str::split(args, ' ' as u8);
+    }
+    fn get_used_link_args() -> vec[str] {
+        ret used_link_args;
+    }
+    fn add_used_library(&str lib) -> bool {
         if (lib == "") {
-            ret;
+            ret false;
         }
         // A program has a small number of libraries, so a vector is probably
         // a good data structure in here.
         for (str l in used_libraries) {
             if (l == lib) {
-                ret;
+                ret false;
             }
         }
         used_libraries += [lib];
+        ret true;
     }
     fn get_used_libraries() -> vec[str] {
        ret used_libraries;

src/comp/lib/llvm.rs

@@ -125,6 +125,7 @@ const uint LLVMRealULT = 12u;
 const uint LLVMRealULE = 13u;
 const uint LLVMRealUNE = 14u;
 
+#[link_args = "-Lrustllvm"]
 native mod llvm = "rustllvm" {
 
     type ModuleRef;

src/comp/metadata/creader.rs

@@ -170,9 +170,25 @@ fn visit_view_item(env e, &@ast::view_item i) {
 fn visit_item(env e, &@ast::item i) {
     alt (i.node) {
         case (ast::item_native_mod(?m)) {
-            if (m.abi == ast::native_abi_rust ||
-                m.abi == ast::native_abi_cdecl) {
-                e.sess.add_used_library(m.native_name);
+            if (m.abi != ast::native_abi_rust &&
+                m.abi != ast::native_abi_cdecl) {
+                ret;
+            }
+            if (!e.sess.add_used_library(m.native_name)) {
+                ret;
+            }
+            for (ast::attribute a in i.attrs) {
+                auto v = a.node.value.node;
+                alt (v) {
+                    case (ast::meta_name_value(?i, ?s)) {
+                        if (i != "link_args") {
+                            cont;
+                        }
+                        e.sess.add_used_link_args(s);
+                    }
+                    case (_) {
+                    }
+                }
             }
         }
         case (_) {