Separating the back folder between backend-agnostic and LLVM-specific code

Author: denismerigoux

src/Cargo.lock

@@ -2132,10 +2132,24 @@ dependencies = [
 name = "rustc_codegen_ssa"
 version = "0.0.0"
 dependencies = [
+ "bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cc 1.0.25 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jobserver 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "memmap 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num_cpus 1.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc 0.0.0",
+ "rustc-demangle 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc_allocator 0.0.0",
+ "rustc_apfloat 0.0.0",
+ "rustc_codegen_utils 0.0.0",
  "rustc_data_structures 0.0.0",
+ "rustc_errors 0.0.0",
+ "rustc_fs_util 0.0.0",
+ "rustc_incremental 0.0.0",
  "rustc_mir 0.0.0",
  "rustc_target 0.0.0",
+ "serialize 0.0.0",
  "syntax 0.0.0",
  "syntax_pos 0.0.0",
 ]

src/librustc_codegen_llvm/back/archive.rs

@@ -18,6 +18,7 @@ use std::ptr;
 use std::str;
 
 use back::bytecode::RLIB_BYTECODE_EXTENSION;
+use rustc_codegen_ssa::back::archive::find_library;
 use libc;
 use llvm::archive_ro::{ArchiveRO, Child};
 use llvm::{self, ArchiveKind};
@@ -52,29 +53,6 @@ enum Addition {
     },
 }
 
-pub fn find_library(name: &str, search_paths: &[PathBuf], sess: &Session)
-                    -> PathBuf {
-    // On Windows, static libraries sometimes show up as libfoo.a and other
-    // times show up as foo.lib
-    let oslibname = format!("{}{}{}",
-                            sess.target.target.options.staticlib_prefix,
-                            name,
-                            sess.target.target.options.staticlib_suffix);
-    let unixlibname = format!("lib{}.a", name);
-
-    for path in search_paths {
-        debug!("looking for {} inside {:?}", name, path);
-        let test = path.join(&oslibname);
-        if test.exists() { return test }
-        if oslibname != unixlibname {
-            let test = path.join(&unixlibname);
-            if test.exists() { return test }
-        }
-    }
-    sess.fatal(&format!("could not find native static library `{}`, \
-                         perhaps an -L flag is missing?", name));
-}
-
 fn is_relevant_child(c: &Child) -> bool {
     match c.name() {
         Some(name) => !name.contains("SYMDEF"),