[WIP] Less hacky way of supporting dylibs

src/Cargo.lock

@@ -1554,6 +1554,7 @@ dependencies = [
  "ar 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "arena 0.0.0",
  "env_logger 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "flate2 0.2.19 (registry+https://github.com/rust-lang/crates.io-index)",
  "graphviz 0.0.0",
  "log 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "owning_ref 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",

src/librustc_driver/Cargo.toml

@@ -10,6 +10,7 @@ crate-type = ["dylib"]
 
 [dependencies]
 arena = { path = "../libarena" }
+flate2 = "0.2"
 graphviz = { path = "../libgraphviz" }
 log = { version = "0.3", features = ["release_max_level_info"] }
 owning_ref = "0.3.3"
@@ -41,4 +42,4 @@ syntax_pos = { path = "../libsyntax_pos" }
 ar = "0.3.0"
 
 [features]
-llvm = ["rustc_trans", "rustc_metadata/llvm"]
+llvm = ["rustc_trans"]

src/librustc_driver/driver.rs

@@ -69,7 +69,7 @@ use derive_registrar;
 
 use profile;
 
-pub fn compile_input(sess: &mut Session,
+pub fn compile_input(sess: &Session,
                      cstore: &CStore,
                      input: &Input,
                      outdir: &Option<PathBuf>,
@@ -100,32 +100,21 @@ pub fn compile_input(sess: &mut Session,
             sess.err("LLVM is not supported by this rustc. Please use -Z no-trans to compile")
         }
 
-        for cty in sess.opts.crate_types.iter_mut() {
+        for cty in sess.opts.crate_types.iter() {
             match *cty {
-                CrateType::CrateTypeRlib | CrateType::CrateTypeExecutable => {},
-                CrateType::CrateTypeDylib | CrateType::CrateTypeCdylib |
-                CrateType::CrateTypeStaticlib => {
+                CrateType::CrateTypeRlib | CrateType::CrateTypeDylib |
+                CrateType::CrateTypeExecutable => {},
+                _ => {
                     sess.parse_sess.span_diagnostic.warn(
-                        &format!("LLVM unsupported, so non rlib output type {} \
-                                  will be treated like rlib lib", cty)
+                        &format!("LLVM unsupported, so output type {} is not supported", cty)
                     );
-                    *cty = CrateType::CrateTypeRlib;
                 },
-                CrateType::CrateTypeProcMacro => {
-                    sess.parse_sess.span_diagnostic.err(
-                        "No LLVM support, so cant compile proc macros"
-                    );
-                }
             }
         }
 
         sess.abort_if_errors();
     }
 
-    // Make sure nobody changes sess after crate types
-    // have optionally been adjusted for no llvm builds
-    let sess = &*sess;
-
     if sess.profile_queries() {
         profile::begin();
     }
@@ -283,7 +272,8 @@ pub fn compile_input(sess: &mut Session,
     if cfg!(not(feature="llvm")) {
         let (_, _) = (outputs, trans);
 
-        if sess.opts.crate_types.contains(&CrateType::CrateTypeRlib) {
+        if sess.opts.crate_types.contains(&CrateType::CrateTypeRlib)
+            || sess.opts.crate_types.contains(&CrateType::CrateTypeDylib) {
             return Ok(())
         }
         sess.fatal("LLVM is not supported by this rustc");

src/librustc_driver/lib.rs

@@ -27,6 +27,8 @@
 
 #[cfg(not(feature="llvm"))]
 extern crate ar;
+#[cfg(not(feature="llvm"))]
+extern crate flate2;
 extern crate arena;
 extern crate getopts;
 extern crate graphviz;
@@ -202,7 +204,8 @@ mod no_llvm_metadata_loader {
                             _target: &Target,
                             _filename: &Path)
                             -> Result<ErasedBoxRef<[u8]>, String> {
-            panic!("Dylib metadata loading not supported without LLVM")
+            // FIXME: Support reading dylibs from llvm enabled rustc
+            self.get_rlib_metadata(_target, _filename)
         }
     }
 }

src/librustc_metadata/Cargo.toml

@@ -21,6 +21,3 @@ serialize = { path = "../libserialize" }
 syntax = { path = "../libsyntax" }
 syntax_ext = { path = "../libsyntax_ext" }
 syntax_pos = { path = "../libsyntax_pos" }
-
-[features]
-llvm = []

src/librustc_metadata/locator.rs

@@ -457,14 +457,6 @@ impl<'a> Context<'a> {
         //
         // The goal of this step is to look at as little metadata as possible.
         self.filesearch.search(|path, kind| {
-            let mut path = path.to_owned();
-            if cfg!(not(feature="llvm")) {
-                // This is a hack to make crates both defined as dylib
-                // and rlib to be findable without LLVM
-                path.set_extension("rlib");
-            }
-            let path = &path;
-
             let file = match path.file_name().and_then(|s| s.to_str()) {
                 None => return FileDoesntMatch,
                 Some(file) => file,
@@ -753,15 +745,7 @@ impl<'a> Context<'a> {
         let mut rmetas = FxHashMap();
         let mut dylibs = FxHashMap();
         {
-            let locs = locs.map(|l| PathBuf::from(l))
-                .map(|mut l| {
-                    if cfg!(not(feature="llvm")) {
-                        // This is a hack to make crates both defined as dylib
-                        // and rlib to be findable without LLVM
-                        l.set_extension("rlib");
-                    }
-                    l
-                }).filter(|loc| {
+            let locs = locs.map(|l| PathBuf::from(l)).filter(|loc| {
                 if !loc.exists() {
                     sess.err(&format!("extern location for {} does not exist: {}",
                                       self.crate_name,