Auto merge of #58847 - bjorn3:remove_metadata_only_cg, r=alexcrichton

Remove metadata only codegen backend

It is unused and probably broken at the moment.

Cargo.lock

@@ -2650,7 +2650,6 @@ dependencies = [
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc 0.0.0",
  "rustc_data_structures 0.0.0",
- "rustc_incremental 0.0.0",
  "rustc_metadata 0.0.0",
  "rustc_mir 0.0.0",
  "rustc_target 0.0.0",

config.toml.example

@@ -14,10 +14,6 @@
 # =============================================================================
 [llvm]
 
-# Indicates whether rustc will support compilation with LLVM
-# note: rustc does not compile without LLVM at the moment
-#enabled = true
-
 # Indicates whether the LLVM build is a Release or Debug build
 #optimize = true
 

src/bootstrap/builder.rs

@@ -996,10 +996,7 @@ impl<'a> Builder<'a> {
         // For other crates, however, we know that we've already got a standard
         // library up and running, so we can use the normal compiler to compile
         // build scripts in that situation.
-        //
-        // If LLVM support is disabled we need to use the snapshot compiler to compile
-        // build scripts, as the new compiler doesn't support executables.
-        if mode == Mode::Std || !self.config.llvm_enabled {
+        if mode == Mode::Std {
             cargo
                 .env("RUSTC_SNAPSHOT", &self.initial_rustc)
                 .env("RUSTC_SNAPSHOT_LIBDIR", self.rustc_snapshot_libdir());

src/bootstrap/config.rs

@@ -64,7 +64,6 @@ pub struct Config {
     pub backtrace_on_ice: bool,
 
     // llvm codegen options
-    pub llvm_enabled: bool,
     pub llvm_assertions: bool,
     pub llvm_optimize: bool,
     pub llvm_thin_lto: bool,
@@ -244,7 +243,6 @@ struct Install {
 #[derive(Deserialize, Default)]
 #[serde(deny_unknown_fields, rename_all = "kebab-case")]
 struct Llvm {
-    enabled: Option<bool>,
     ccache: Option<StringOrBool>,
     ninja: Option<bool>,
     assertions: Option<bool>,
@@ -360,7 +358,6 @@ impl Config {
 
     pub fn default_opts() -> Config {
         let mut config = Config::default();
-        config.llvm_enabled = true;
         config.llvm_optimize = true;
         config.llvm_version_check = true;
         config.backtrace = true;
@@ -512,7 +509,6 @@ impl Config {
                 Some(StringOrBool::Bool(false)) | None => {}
             }
             set(&mut config.ninja, llvm.ninja);
-            set(&mut config.llvm_enabled, llvm.enabled);
             llvm_assertions = llvm.assertions;
             set(&mut config.llvm_optimize, llvm.optimize);
             set(&mut config.llvm_thin_lto, llvm.thin_lto);
@@ -671,6 +667,11 @@ impl Config {
     pub fn very_verbose(&self) -> bool {
         self.verbose > 1
     }
+
+    pub fn llvm_enabled(&self) -> bool {
+        self.rust_codegen_backends.contains(&INTERNER.intern_str("llvm"))
+        || self.rust_codegen_backends.contains(&INTERNER.intern_str("emscripten"))
+    }
 }
 
 fn set<T>(field: &mut T, val: Option<T>) {

src/bootstrap/test.rs

@@ -1194,7 +1194,7 @@ impl Step for Compiletest {
             cmd.arg("--quiet");
         }
 
-        if builder.config.llvm_enabled {
+        if builder.config.llvm_enabled() {
             let llvm_config = builder.ensure(native::Llvm {
                 target: builder.config.build,
                 emscripten: false,
@@ -1227,12 +1227,6 @@ impl Step for Compiletest {
                 }
             }
         }
-        if suite == "run-make-fulldeps" && !builder.config.llvm_enabled {
-            builder.info(
-                "Ignoring run-make test suite as they generally don't work without LLVM"
-            );
-            return;
-        }
 
         if suite != "run-make-fulldeps" {
             cmd.arg("--cc")

src/bootstrap/tool.rs

@@ -700,7 +700,7 @@ impl<'a> Builder<'a> {
     }
 
     fn llvm_bin_path(&self) -> Option<PathBuf> {
-        if self.config.llvm_enabled {
+        if self.config.llvm_enabled() {
             let llvm_config = self.ensure(native::Llvm {
                 target: self.config.build,
                 emscripten: false,

src/librustc_codegen_utils/Cargo.toml

@@ -21,4 +21,3 @@ rustc_target = { path = "../librustc_target" }
 rustc_data_structures = { path = "../librustc_data_structures" }
 rustc_metadata = { path = "../librustc_metadata" }
 rustc_mir = { path = "../librustc_mir" }
-rustc_incremental = { path = "../librustc_incremental" }

src/librustc_codegen_utils/codegen_backend.rs

@@ -10,27 +10,16 @@
 #![feature(box_syntax)]
 
 use std::any::Any;
-use std::io::Write;
-use std::fs;
-use std::path::Path;
-use std::sync::{mpsc, Arc};
-
-use rustc_data_structures::owning_ref::OwningRef;
-use flate2::Compression;
-use flate2::write::DeflateEncoder;
+use std::sync::mpsc;
 
 use syntax::symbol::Symbol;
-use rustc::hir::def_id::LOCAL_CRATE;
 use rustc::session::Session;
 use rustc::util::common::ErrorReported;
-use rustc::session::config::{CrateType, OutputFilenames, PrintRequest};
+use rustc::session::config::{OutputFilenames, PrintRequest};
 use rustc::ty::TyCtxt;
 use rustc::ty::query::Providers;
-use rustc::middle::cstore::EncodedMetadata;
 use rustc::middle::cstore::MetadataLoader;
 use rustc::dep_graph::DepGraph;
-use rustc_target::spec::Target;
-use crate::link::out_filename;
 
 pub use rustc_data_structures::sync::MetadataRef;
 
@@ -64,134 +53,3 @@ pub trait CodegenBackend {
         outputs: &OutputFilenames,
     ) -> Result<(), ErrorReported>;
 }
-
-pub struct NoLlvmMetadataLoader;
-
-impl MetadataLoader for NoLlvmMetadataLoader {
-    fn get_rlib_metadata(&self, _: &Target, filename: &Path) -> Result<MetadataRef, String> {
-        let buf = fs::read(filename).map_err(|e| format!("metadata file open err: {:?}", e))?;
-        let buf: OwningRef<Vec<u8>, [u8]> = OwningRef::new(buf);
-        Ok(rustc_erase_owner!(buf.map_owner_box()))
-    }
-
-    fn get_dylib_metadata(&self, target: &Target, filename: &Path) -> Result<MetadataRef, String> {
-        self.get_rlib_metadata(target, filename)
-    }
-}
-
-pub struct MetadataOnlyCodegenBackend(());
-pub struct OngoingCodegen {
-    metadata: EncodedMetadata,
-    metadata_version: Vec<u8>,
-    crate_name: Symbol,
-}
-
-impl MetadataOnlyCodegenBackend {
-    pub fn boxed() -> Box<dyn CodegenBackend> {
-        box MetadataOnlyCodegenBackend(())
-    }
-}
-
-impl CodegenBackend for MetadataOnlyCodegenBackend {
-    fn init(&self, sess: &Session) {
-        for cty in sess.opts.crate_types.iter() {
-            match *cty {
-                CrateType::Rlib | CrateType::Dylib | CrateType::Executable => {},
-                _ => {
-                    sess.diagnostic().warn(
-                        &format!("LLVM unsupported, so output type {} is not supported", cty)
-                    );
-                },
-            }
-        }
-    }
-
-    fn metadata_loader(&self) -> Box<dyn MetadataLoader + Sync> {
-        box NoLlvmMetadataLoader
-    }
-
-    fn provide(&self, providers: &mut Providers<'_>) {
-        crate::symbol_names::provide(providers);
-
-        providers.target_features_whitelist = |_tcx, _cnum| {
-            Default::default() // Just a dummy
-        };
-        providers.is_reachable_non_generic = |_tcx, _defid| true;
-        providers.exported_symbols = |_tcx, _crate| Arc::new(Vec::new());
-    }
-    fn provide_extern(&self, providers: &mut Providers<'_>) {
-        providers.is_reachable_non_generic = |_tcx, _defid| true;
-    }
-
-    fn codegen_crate<'a, 'tcx>(
-        &self,
-        tcx: TyCtxt<'a, 'tcx, 'tcx>,
-        _rx: mpsc::Receiver<Box<dyn Any + Send>>
-    ) -> Box<dyn Any> {
-        use rustc_mir::monomorphize::item::MonoItem;
-
-        crate::check_for_rustc_errors_attr(tcx);
-        crate::symbol_names_test::report_symbol_names(tcx);
-        rustc_incremental::assert_dep_graph(tcx);
-        rustc_incremental::assert_module_sources::assert_module_sources(tcx);
-        // FIXME: Fix this
-        // rustc::middle::dependency_format::calculate(tcx);
-        let _ = tcx.link_args(LOCAL_CRATE);
-        let _ = tcx.native_libraries(LOCAL_CRATE);
-        let (_, cgus) = tcx.collect_and_partition_mono_items(LOCAL_CRATE);
-        for (mono_item, _) in cgus.iter().flat_map(|cgu| cgu.items().iter()) {
-            if let MonoItem::Fn(inst) = mono_item {
-                let def_id = inst.def_id();
-                if def_id.is_local() {
-                    let _ = tcx.codegen_fn_attrs(def_id);
-                }
-            }
-        }
-        tcx.sess.abort_if_errors();
-
-        let metadata = tcx.encode_metadata();
-
-        box OngoingCodegen {
-            metadata,
-            metadata_version: tcx.metadata_encoding_version().to_vec(),
-            crate_name: tcx.crate_name(LOCAL_CRATE),
-        }
-    }
-
-    fn join_codegen_and_link(
-        &self,
-        ongoing_codegen: Box<dyn Any>,
-        sess: &Session,
-        _dep_graph: &DepGraph,
-        outputs: &OutputFilenames,
-    ) -> Result<(), ErrorReported> {
-        let ongoing_codegen = ongoing_codegen.downcast::<OngoingCodegen>()
-            .expect("Expected MetadataOnlyCodegenBackend's OngoingCodegen, found Box<dyn Any>");
-        for &crate_type in sess.opts.crate_types.iter() {
-            if crate_type != CrateType::Rlib &&
-               crate_type != CrateType::Dylib {
-                continue;
-            }
-            let output_name =
-                out_filename(sess, crate_type, &outputs, &ongoing_codegen.crate_name.as_str());
-            let mut compressed = ongoing_codegen.metadata_version.clone();
-            let metadata = if crate_type == CrateType::Dylib {
-                DeflateEncoder::new(&mut compressed, Compression::fast())
-                    .write_all(&ongoing_codegen.metadata.raw_data)
-                    .unwrap();
-                &compressed
-            } else {
-                &ongoing_codegen.metadata.raw_data
-            };
-            fs::write(&output_name, metadata).unwrap();
-        }
-
-        sess.abort_if_errors();
-        if !sess.opts.crate_types.contains(&CrateType::Rlib)
-            && !sess.opts.crate_types.contains(&CrateType::Dylib)
-        {
-            sess.fatal("Executables are not supported by the metadata-only backend.");
-        }
-        Ok(())
-    }
-}

src/librustc_codegen_utils/lib.rs

@@ -19,7 +19,6 @@
 
 #[macro_use]
 extern crate rustc;
-#[macro_use] extern crate rustc_data_structures;
 
 use rustc::ty::TyCtxt;
 use rustc::hir::def_id::LOCAL_CRATE;

src/librustc_driver/lib.rs

@@ -91,9 +91,6 @@ use syntax::feature_gate::{GatedCfg, UnstableFeatures};
 use syntax::parse::{self, PResult};
 use syntax_pos::{DUMMY_SP, MultiSpan, FileName};
 
-#[cfg(test)]
-mod test;
-
 pub mod pretty;
 
 /// Exit status code used for successful compilation and help output.