Make rustc compile without LLVM

Doesn't yet compile when `llvm-enabled = false` due to crate metadata loading needing LLVM

src/librustc_driver/Cargo.toml

@@ -29,9 +29,12 @@ rustc_plugin = { path = "../librustc_plugin" }
 rustc_privacy = { path = "../librustc_privacy" }
 rustc_resolve = { path = "../librustc_resolve" }
 rustc_save_analysis = { path = "../librustc_save_analysis" }
-rustc_trans = { path = "../librustc_trans" }
+rustc_trans = { path = "../librustc_trans", optional=true }
 rustc_typeck = { path = "../librustc_typeck" }
 serialize = { path = "../libserialize" }
 syntax = { path = "../libsyntax" }
 syntax_ext = { path = "../libsyntax_ext" }
 syntax_pos = { path = "../libsyntax_pos" }
+
+[features]
+llvm = ["rustc_trans"]

src/librustc_driver/driver.rs

@@ -31,7 +31,11 @@ use rustc_incremental::{self, IncrementalHashesMap};
 use rustc_resolve::{MakeGlobMap, Resolver};
 use rustc_metadata::creader::CrateLoader;
 use rustc_metadata::cstore::{self, CStore};
+#[cfg(feature="llvm")]
 use rustc_trans::back::{link, write};
+#[cfg(not(feature="llvm"))]
+use ::link;
+#[cfg(feature="llvm")]
 use rustc_trans as trans;
 use rustc_typeck as typeck;
 use rustc_privacy;
@@ -111,7 +115,7 @@ pub fn compile_input(sess: &Session,
         };
 
         let outputs = build_output_filenames(input, outdir, output, &krate.attrs, sess);
-        let crate_name = link::find_crate_name(Some(sess), &krate.attrs, input);
+        let crate_name: String = link::find_crate_name(Some(sess), &krate.attrs, input);
         let ExpansionResult { expanded_crate, defs, analysis, resolutions, mut hir_forest } = {
             phase_2_configure_and_expand(
                 sess, &cstore, krate, registry, &crate_name, addl_plugins, control.make_glob_map,
@@ -204,55 +208,71 @@ pub fn compile_input(sess: &Session,
                 println!("Pre-trans");
                 tcx.print_debug_stats();
             }
-            let trans = phase_4_translate_to_llvm(tcx, analysis, &incremental_hashes_map,
-                                                  &outputs);
 
-            if log_enabled!(::log::LogLevel::Info) {
-                println!("Post-trans");
-                tcx.print_debug_stats();
-            }
+            #[cfg(feature="llvm")]
+            {
+                let trans = phase_4_translate_to_llvm(tcx, analysis, &incremental_hashes_map,
+                                                    &outputs);
+
+                if log_enabled!(::log::LogLevel::Info) {
+                    println!("Post-trans");
+                    tcx.print_debug_stats();
+                }
 
-            if tcx.sess.opts.output_types.contains_key(&OutputType::Mir) {
-                if let Err(e) = mir::transform::dump_mir::emit_mir(tcx, &outputs) {
-                    sess.err(&format!("could not emit MIR: {}", e));
-                    sess.abort_if_errors();
+                if tcx.sess.opts.output_types.contains_key(&OutputType::Mir) {
+                    if let Err(e) = mir::transform::dump_mir::emit_mir(tcx, &outputs) {
+                        sess.err(&format!("could not emit MIR: {}", e));
+                        sess.abort_if_errors();
+                    }
                 }
+
+                return Ok((outputs, trans))
             }
 
-            Ok((outputs, trans))
+            #[cfg(not(feature="llvm"))]
+            panic!("Unreachable")
         })??
     };
 
     if sess.opts.debugging_opts.print_type_sizes {
         sess.code_stats.borrow().print_type_sizes();
     }
 
-    let phase5_result = phase_5_run_llvm_passes(sess, &trans, &outputs);
+    #[cfg(feature="llvm")]
+    {
+        let phase5_result = phase_5_run_llvm_passes(sess, &trans, &outputs);
 
-    controller_entry_point!(after_llvm,
-                            sess,
-                            CompileState::state_after_llvm(input, sess, outdir, output, &trans),
-                            phase5_result);
-    phase5_result?;
+        controller_entry_point!(after_llvm,
+                                sess,
+                                CompileState::state_after_llvm(input, sess, outdir, output, &trans),
+                                phase5_result);
+        phase5_result?;
 
-    write::cleanup_llvm(&trans);
+        write::cleanup_llvm(&trans);
 
-    phase_6_link_output(sess, &trans, &outputs);
+        phase_6_link_output(sess, &trans, &outputs);
 
-    // Now that we won't touch anything in the incremental compilation directory
-    // any more, we can finalize it (which involves renaming it)
-    rustc_incremental::finalize_session_directory(sess, trans.link.crate_hash);
+        // Now that we won't touch anything in the incremental compilation directory
+        // any more, we can finalize it (which involves renaming it)
+        rustc_incremental::finalize_session_directory(sess, trans.link.crate_hash);
 
-    if sess.opts.debugging_opts.perf_stats {
-        sess.print_perf_stats();
-    }
+        if sess.opts.debugging_opts.perf_stats {
+            sess.print_perf_stats();
+        }
+
+        controller_entry_point!(compilation_done,
+                                sess,
+                                CompileState::state_when_compilation_done(input,
+                                                                          sess,
+                                                                          outdir,
+                                                                          output),
+                                Ok(()));
 
-    controller_entry_point!(compilation_done,
-                            sess,
-                            CompileState::state_when_compilation_done(input, sess, outdir, output),
-                            Ok(()));
+        return Ok(())
+    }
 
-    Ok(())
+    #[cfg(not(feature="llvm"))]
+    panic!("Unreachable")
 }
 
 fn keep_hygiene_data(sess: &Session) -> bool {
@@ -355,6 +375,7 @@ pub struct CompileState<'a, 'tcx: 'a> {
     pub resolutions: Option<&'a Resolutions>,
     pub analysis: Option<&'a ty::CrateAnalysis>,
     pub tcx: Option<TyCtxt<'a, 'tcx, 'tcx>>,
+    #[cfg(feature="llvm")]
     pub trans: Option<&'a trans::CrateTranslation>,
 }
 
@@ -381,6 +402,7 @@ impl<'a, 'tcx> CompileState<'a, 'tcx> {
             resolutions: None,
             analysis: None,
             tcx: None,
+            #[cfg(feature="llvm")]
             trans: None,
         }
     }
@@ -470,6 +492,7 @@ impl<'a, 'tcx> CompileState<'a, 'tcx> {
     }
 
 
+    #[cfg(feature="llvm")]
     fn state_after_llvm(input: &'a Input,
                         session: &'tcx Session,
                         out_dir: &'a Option<PathBuf>,
@@ -893,6 +916,7 @@ pub fn phase_3_run_analysis_passes<'tcx, F, R>(sess: &'tcx Session,
     mir::provide(&mut local_providers);
     reachable::provide(&mut local_providers);
     rustc_privacy::provide(&mut local_providers);
+    #[cfg(feature="llvm")]
     trans::provide(&mut local_providers);
     typeck::provide(&mut local_providers);
     ty::provide(&mut local_providers);
@@ -904,6 +928,7 @@ pub fn phase_3_run_analysis_passes<'tcx, F, R>(sess: &'tcx Session,
 
     let mut extern_providers = ty::maps::Providers::default();
     cstore::provide(&mut extern_providers);
+    #[cfg(feature="llvm")]
     trans::provide(&mut extern_providers);
     ty::provide_extern(&mut extern_providers);
     traits::provide_extern(&mut extern_providers);
@@ -1045,6 +1070,7 @@ pub fn phase_3_run_analysis_passes<'tcx, F, R>(sess: &'tcx Session,
 
 /// Run the translation phase to LLVM, after which the AST and analysis can
 /// be discarded.
+#[cfg(feature="llvm")]
 pub fn phase_4_translate_to_llvm<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                                            analysis: ty::CrateAnalysis,
                                            incremental_hashes_map: &IncrementalHashesMap,
@@ -1076,6 +1102,7 @@ pub fn phase_4_translate_to_llvm<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 
 /// Run LLVM itself, producing a bitcode file, assembly file or object file
 /// as a side effect.
+#[cfg(feature="llvm")]
 pub fn phase_5_run_llvm_passes(sess: &Session,
                                trans: &trans::CrateTranslation,
                                outputs: &OutputFilenames) -> CompileResult {
@@ -1124,6 +1151,7 @@ pub fn phase_5_run_llvm_passes(sess: &Session,
 
 /// Run the linker on any artifacts that resulted from the LLVM run.
 /// This should produce either a finished executable or library.
+#[cfg(feature="llvm")]
 pub fn phase_6_link_output(sess: &Session,
                            trans: &trans::CrateTranslation,
                            outputs: &OutputFilenames) {

src/librustc_driver/lib.rs

@@ -48,6 +48,7 @@ extern crate rustc_metadata;
 extern crate rustc_mir;
 extern crate rustc_resolve;
 extern crate rustc_save_analysis;
+#[cfg(feature="llvm")]
 extern crate rustc_trans;
 extern crate rustc_typeck;
 extern crate serialize;
@@ -63,7 +64,9 @@ use pretty::{PpMode, UserIdentifiedItem};
 use rustc_resolve as resolve;
 use rustc_save_analysis as save;
 use rustc_save_analysis::DumpHandler;
+#[cfg(feature="llvm")]
 use rustc_trans::back::link;
+#[cfg(feature="llvm")]
 use rustc_trans::back::write::{RELOC_MODEL_ARGS, CODE_GEN_MODEL_ARGS};
 use rustc::dep_graph::DepGraph;
 use rustc::session::{self, config, Session, build_session, CompileResult};
@@ -175,6 +178,7 @@ pub fn run_compiler<'a>(args: &[String],
     let (sopts, cfg) = config::build_session_options_and_crate_config(&matches);
 
     if sopts.debugging_opts.debug_llvm {
+        #[cfg(feature="llvm")]
         rustc_trans::enable_llvm_debug();
     }
 
@@ -204,6 +208,7 @@ pub fn run_compiler<'a>(args: &[String],
     let mut sess = session::build_session_with_codemap(
         sopts, &dep_graph, input_file_path, descriptions, cstore.clone(), codemap, emitter_dest,
     );
+    #[cfg(feature="llvm")]
     rustc_trans::init(&sess);
     rustc_lint::register_builtins(&mut sess.lint_store.borrow_mut(), Some(&sess));
 
@@ -409,6 +414,7 @@ impl<'a> CompilerCalls<'a> for RustcDefaultCalls {
                     None,
                     descriptions.clone(),
                     cstore.clone());
+                #[cfg(feature="llvm")]
                 rustc_trans::init(&sess);
                 rustc_lint::register_builtins(&mut sess.lint_store.borrow_mut(), Some(&sess));
                 let mut cfg = config::build_configuration(&sess, cfg.clone());
@@ -607,7 +613,7 @@ impl RustcDefaultCalls {
                     };
                     let attrs = attrs.as_ref().unwrap();
                     let t_outputs = driver::build_output_filenames(input, odir, ofile, attrs, sess);
-                    let id = link::find_crate_name(Some(sess), attrs, input);
+                    let id: String = link::find_crate_name(Some(sess), attrs, input);
                     if *req == PrintRequest::CrateName {
                         println!("{}", id);
                         continue;
@@ -662,20 +668,36 @@ impl RustcDefaultCalls {
                     }
                 }
                 PrintRequest::RelocationModels => {
-                    println!("Available relocation models:");
-                    for &(name, _) in RELOC_MODEL_ARGS.iter() {
-                        println!("    {}", name);
+                    #[cfg(not(feature="llvm"))]
+                    panic!("LLVM is not enabled for this rustc version");
+
+                    #[cfg(feature="llvm")]
+                    {
+                        println!("Available relocation models:");
+                        for &(name, _) in RELOC_MODEL_ARGS.iter() {
+                            println!("    {}", name);
+                        }
+                        println!("");
                     }
-                    println!("");
                 }
                 PrintRequest::CodeModels => {
-                    println!("Available code models:");
-                    for &(name, _) in CODE_GEN_MODEL_ARGS.iter(){
-                        println!("    {}", name);
+                    #[cfg(not(feature="llvm"))]
+                    panic!("LLVM is not enabled for this rustc version");
+
+                    #[cfg(feature="llvm")]
+                    {
+                        println!("Available code models:");
+                        for &(name, _) in CODE_GEN_MODEL_ARGS.iter(){
+                            println!("    {}", name);
+                        }
+                        println!("");
                     }
-                    println!("");
                 }
                 PrintRequest::TargetCPUs | PrintRequest::TargetFeatures => {
+                    #[cfg(not(feature="llvm"))]
+                    panic!("LLVM is not enabled for this rustc version");
+
+                    #[cfg(feature="llvm")]
                     rustc_trans::print(*req, sess);
                 }
             }
@@ -715,6 +737,7 @@ pub fn version(binary: &str, matches: &getopts::Matches) {
         println!("commit-date: {}", unw(commit_date_str()));
         println!("host: {}", config::host_triple());
         println!("release: {}", unw(release_str()));
+        #[cfg(feature="llvm")]
         rustc_trans::print_version();
     }
 }
@@ -1008,6 +1031,10 @@ pub fn handle_options(args: &[String]) -> Option<getopts::Matches> {
     }
 
     if cg_flags.contains(&"passes=list".to_string()) {
+        #[cfg(not(feature="llvm"))]
+        panic!("LLVM is not enabled for this rustc version");
+
+        #[cfg(feature="llvm")]
         rustc_trans::print_passes();
         return None;
     }
@@ -1135,6 +1162,7 @@ pub fn diagnostics_registry() -> errors::registry::Registry {
     all_errors.extend_from_slice(&rustc_borrowck::DIAGNOSTICS);
     all_errors.extend_from_slice(&rustc_resolve::DIAGNOSTICS);
     all_errors.extend_from_slice(&rustc_privacy::DIAGNOSTICS);
+    #[cfg(feature="llvm")]
     all_errors.extend_from_slice(&rustc_trans::DIAGNOSTICS);
     all_errors.extend_from_slice(&rustc_const_eval::DIAGNOSTICS);
     all_errors.extend_from_slice(&rustc_metadata::DIAGNOSTICS);
@@ -1159,3 +1187,9 @@ pub fn main() {
                                      None));
     process::exit(result as i32);
 }
+
+
+#[cfg(not(feature="llvm"))]
+mod link {
+    include!("../librustc_trans/back/no_llvm_link.rs");
+}

src/librustc_driver/target_features.rs

@@ -11,6 +11,7 @@
 use syntax::ast;
 use rustc::session::Session;
 use syntax::symbol::Symbol;
+#[cfg(feature="llvm")]
 use rustc_trans;
 
 /// Add `target_feature = "..."` cfgs for a variety of platform
@@ -21,6 +22,7 @@ use rustc_trans;
 pub fn add_configuration(cfg: &mut ast::CrateConfig, sess: &Session) {
     let tf = Symbol::intern("target_feature");
 
+    #[cfg(feature="llvm")]
     for feat in rustc_trans::target_features(sess) {
         cfg.insert((tf, Some(feat)));
     }

src/librustc_driver/test.rs

@@ -14,6 +14,7 @@ use driver;
 use rustc::dep_graph::DepGraph;
 use rustc_lint;
 use rustc_resolve::MakeGlobMap;
+#[cfg(feature="llvm")]
 use rustc_trans;
 use rustc::middle::lang_items;
 use rustc::middle::free_region::FreeRegionMap;
@@ -113,6 +114,7 @@ fn test_env<F>(source_string: &str,
                                        diagnostic_handler,
                                        Rc::new(CodeMap::new(FilePathMapping::empty())),
                                        cstore.clone());
+    #[cfg(feature="llvm")]
     rustc_trans::init(&sess);
     rustc_lint::register_builtins(&mut sess.lint_store.borrow_mut(), Some(&sess));
     let input = config::Input::Str {