Move metadata encoding earlier.

This commit separates metadata encoding (`tcx.encode_metadata`) from the
creation of the metadata module (which is now handled by
`write_compressed_metadata`, formerly `write_metadata`).

The metadata encoding now occurs slightly earlier in the pipeline, at
the very start of code generation within `start_codegen`.

Metadata *writing* still occurs near the end of compilation; that will
be moved forward in subsequent commits.

1 files changed, 3 insertions, 1 deletions

diff --git a/src/librustc_codegen_utils/codegen_backend.rs b/src/librustc_codegen_utils/codegen_backend.rs
index 56eaffb1ca3..191c6605b43 100644
--- a/src/librustc_codegen_utils/codegen_backend.rs
+++ b/src/librustc_codegen_utils/codegen_backend.rs
@@ -18,7 +18,7 @@ use rustc::util::common::ErrorReported;
 use rustc::session::config::{OutputFilenames, PrintRequest};
 use rustc::ty::TyCtxt;
 use rustc::ty::query::Providers;
-use rustc::middle::cstore::MetadataLoader;
+use rustc::middle::cstore::{EncodedMetadata, MetadataLoader};
 use rustc::dep_graph::DepGraph;
 
 pub use rustc_data_structures::sync::MetadataRef;
@@ -37,6 +37,8 @@ pub trait CodegenBackend {
     fn codegen_crate<'a, 'tcx>(
         &self,
         tcx: TyCtxt<'a, 'tcx, 'tcx>,
+        metadata: EncodedMetadata,
+        need_metadata_module: bool,
         rx: mpsc::Receiver<Box<dyn Any + Send>>
     ) -> Box<dyn Any>;