src/test/run-make-fulldeps/hotplug_codegen_backend/the_backend.rs

   1 #![feature(rustc_private)]
   2
   3 extern crate rustc;
   4 extern crate rustc_codegen_utils;
   5 #[macro_use]
   6 extern crate rustc_data_structures;
   7 extern crate rustc_hir;
   8 extern crate rustc_target;
   9 extern crate rustc_driver;
  10 extern crate rustc_span;
  11
  12 use std::any::Any;
  13 use std::sync::Arc;
  14 use std::path::Path;
  15 use rustc_span::symbol::Symbol;
  16 use rustc::session::Session;
  17 use rustc::session::config::OutputFilenames;
  18 use rustc::ty::TyCtxt;
  19 use rustc::ty::query::Providers;
  20 use rustc::middle::cstore::{EncodedMetadata, MetadataLoader, MetadataLoaderDyn};
  21 use rustc::dep_graph::DepGraph;
  22 use rustc::util::common::ErrorReported;
  23 use rustc_codegen_utils::codegen_backend::CodegenBackend;
  24 use rustc_data_structures::sync::MetadataRef;
  25 use rustc_data_structures::owning_ref::OwningRef;
  26 use rustc_target::spec::Target;
  27
  28 pub struct NoLlvmMetadataLoader;
  29
  30 impl MetadataLoader for NoLlvmMetadataLoader {
  31     fn get_rlib_metadata(&self, _: &Target, filename: &Path) -> Result<MetadataRef, String> {
  32         let buf = std::fs::read(filename).map_err(|e| format!("metadata file open err: {:?}", e))?;
  33         let buf: OwningRef<Vec<u8>, [u8]> = OwningRef::new(buf);
  34         Ok(rustc_erase_owner!(buf.map_owner_box()))
  35     }
  36
  37     fn get_dylib_metadata(&self, target: &Target, filename: &Path) -> Result<MetadataRef, String> {
  38         self.get_rlib_metadata(target, filename)
  39     }
  40 }
  41
  42 struct TheBackend;
  43
  44 impl CodegenBackend for TheBackend {
  45     fn metadata_loader(&self) -> Box<MetadataLoaderDyn> {
  46         Box::new(NoLlvmMetadataLoader)
  47     }
  48
  49     fn provide(&self, providers: &mut Providers) {
  50         rustc_codegen_utils::symbol_names::provide(providers);
  51
  52         providers.target_features_whitelist = |tcx, _cnum| {
  53             tcx.arena.alloc(Default::default()) // Just a dummy
  54         };
  55         providers.is_reachable_non_generic = |_tcx, _defid| true;
  56         providers.exported_symbols = |_tcx, _crate| Arc::new(Vec::new());
  57     }
  58
  59     fn provide_extern(&self, providers: &mut Providers) {
  60         providers.is_reachable_non_generic = |_tcx, _defid| true;
  61     }
  62
  63     fn codegen_crate<'a, 'tcx>(
  64         &self,
  65         tcx: TyCtxt<'tcx>,
  66         _metadata: EncodedMetadata,
  67         _need_metadata_module: bool,
  68     ) -> Box<dyn Any> {
  69         use rustc_hir::def_id::LOCAL_CRATE;
  70
  71         Box::new(tcx.crate_name(LOCAL_CRATE) as Symbol)
  72     }
  73
  74     fn join_codegen(
  75         &self,
  76         ongoing_codegen: Box<dyn Any>,
  77         _sess: &Session,
  78         _dep_graph: &DepGraph,
  79     ) -> Result<Box<dyn Any>, ErrorReported> {
  80         let crate_name = ongoing_codegen.downcast::<Symbol>()
  81             .expect("in join_codegen: ongoing_codegen is not a Symbol");
  82         Ok(crate_name)
  83     }
  84
  85     fn link(
  86         &self,
  87         sess: &Session,
  88         codegen_results: Box<dyn Any>,
  89         outputs: &OutputFilenames,
  90     ) -> Result<(), ErrorReported> {
  91         use std::io::Write;
  92         use rustc::session::config::CrateType;
  93         use rustc_codegen_utils::link::out_filename;
  94         let crate_name = codegen_results.downcast::<Symbol>()
  95             .expect("in link: codegen_results is not a Symbol");
  96         for &crate_type in sess.opts.crate_types.iter() {
  97             if crate_type != CrateType::Rlib {
  98                 sess.fatal(&format!("Crate type is {:?}", crate_type));
  99             }
 100             let output_name =
 101                 out_filename(sess, crate_type, &outputs, &*crate_name.as_str());
 102             let mut out_file = ::std::fs::File::create(output_name).unwrap();
 103             write!(out_file, "This has been \"compiled\" successfully.").unwrap();
 104         }
 105         Ok(())
 106     }
 107 }
 108
 109 /// This is the entrypoint for a hot plugged rustc_codegen_llvm
 110 #[no_mangle]
 111 pub fn __rustc_codegen_backend() -> Box<dyn CodegenBackend> {
 112     Box::new(TheBackend)
 113 }