Move encode_metadata out of CrateStore.

Author: cjgillot

compiler/rustc_interface/src/callbacks.rs

@@ -11,6 +11,7 @@
 
 use rustc_errors::{Diagnostic, TRACK_DIAGNOSTICS};
 use rustc_middle::ty::tls;
+use rustc_middle::ty::TyCtxt;
 use std::fmt;
 
 /// This is a callback from librustc_ast as it cannot access the implicit state
@@ -57,5 +58,7 @@ fn def_id_debug(def_id: rustc_hir::def_id::DefId, f: &mut fmt::Formatter<'_>) ->
 pub fn setup_callbacks() {
     rustc_span::SPAN_DEBUG.swap(&(span_debug as fn(_, &mut fmt::Formatter<'_>) -> _));
     rustc_hir::def_id::DEF_ID_DEBUG.swap(&(def_id_debug as fn(_, &mut fmt::Formatter<'_>) -> _));
+    rustc_middle::ty::ENCODE_METADATA
+        .swap(&(rustc_metadata::encode_metadata as fn(TyCtxt<'_>) -> _));
     TRACK_DIAGNOSTICS.swap(&(track_diagnostic as fn(&_)));
 }

compiler/rustc_metadata/src/lib.rs

@@ -34,3 +34,5 @@ mod rmeta;
 pub mod creader;
 pub mod dynamic_lib;
 pub mod locator;
+
+pub use rmeta::encode_metadata;

compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs

@@ -2,7 +2,7 @@ use crate::creader::{CStore, LoadedMacro};
 use crate::foreign_modules;
 use crate::link_args;
 use crate::native_libs;
-use crate::rmeta::{self, encoder};
+use crate::rmeta;
 
 use rustc_ast as ast;
 use rustc_ast::expand::allocator::AllocatorKind;
@@ -14,7 +14,7 @@ use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, CRATE_DEF_INDEX, LOCAL_CRATE}
 use rustc_hir::definitions::{DefKey, DefPath, DefPathHash};
 use rustc_middle::hir::exports::Export;
 use rustc_middle::middle::cstore::ForeignModule;
-use rustc_middle::middle::cstore::{CrateSource, CrateStore, EncodedMetadata};
+use rustc_middle::middle::cstore::{CrateSource, CrateStore};
 use rustc_middle::middle::exported_symbols::ExportedSymbol;
 use rustc_middle::middle::stability::DeprecationEntry;
 use rustc_middle::ty::query::Providers;
@@ -512,10 +512,6 @@ impl CrateStore for CStore {
         result
     }
 
-    fn encode_metadata(&self, tcx: TyCtxt<'_>) -> EncodedMetadata {
-        encoder::encode_metadata(tcx)
-    }
-
     fn metadata_encoding_version(&self) -> &[u8] {
         rmeta::METADATA_HEADER
     }

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -2002,7 +2002,7 @@ impl<'tcx, 'v> ParItemLikeVisitor<'v> for PrefetchVisitor<'tcx> {
 // will allow us to slice the metadata to the precise length that we just
 // generated regardless of trailing bytes that end up in it.
 
-pub(super) fn encode_metadata(tcx: TyCtxt<'_>) -> EncodedMetadata {
+pub fn encode_metadata(tcx: TyCtxt<'_>) -> EncodedMetadata {
     // Since encoding metadata is not in a query, and nothing is cached,
     // there's no need to do dep-graph tracking for any of it.
     tcx.dep_graph.assert_ignored();

compiler/rustc_metadata/src/rmeta/mod.rs

@@ -30,6 +30,7 @@ use std::num::NonZeroUsize;
 use decoder::DecodeContext;
 pub use decoder::{provide, provide_extern};
 crate use decoder::{CrateMetadata, CrateNumMap, MetadataBlob};
+pub use encoder::encode_metadata;
 use encoder::EncodeContext;
 use rustc_span::hygiene::SyntaxContextData;
 

compiler/rustc_middle/src/middle/cstore.rs

@@ -203,7 +203,6 @@ pub trait CrateStore {
     fn crates_untracked(&self) -> Vec<CrateNum>;
 
     // utility functions
-    fn encode_metadata(&self, tcx: TyCtxt<'_>) -> EncodedMetadata;
     fn metadata_encoding_version(&self) -> &[u8];
     fn allocator_kind(&self) -> Option<AllocatorKind>;
 }

compiler/rustc_middle/src/ty/context.rs

@@ -35,6 +35,7 @@ use rustc_data_structures::stable_hasher::{
 use rustc_data_structures::steal::Steal;
 use rustc_data_structures::sync::{self, Lock, Lrc, WorkerLocal};
 use rustc_data_structures::unhash::UnhashMap;
+use rustc_data_structures::AtomicRef;
 use rustc_errors::ErrorReported;
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
@@ -979,6 +980,12 @@ pub struct GlobalCtxt<'tcx> {
     output_filenames: Arc<OutputFilenames>,
 }
 
+fn dummy_encode_metadata(_: TyCtxt<'_>) -> EncodedMetadata {
+    panic!("Unregistered callback to `encode_metadata`.")
+}
+pub static ENCODE_METADATA: AtomicRef<fn(TyCtxt<'_>) -> EncodedMetadata> =
+    AtomicRef::new(&(dummy_encode_metadata as fn(TyCtxt<'_>) -> _));
+
 impl<'tcx> TyCtxt<'tcx> {
     pub fn typeck_opt_const_arg(
         self,
@@ -1279,7 +1286,7 @@ impl<'tcx> TyCtxt<'tcx> {
 
     pub fn encode_metadata(self) -> EncodedMetadata {
         let _prof_timer = self.prof.verbose_generic_activity("generate_crate_metadata");
-        self.cstore.encode_metadata(self)
+        (*ENCODE_METADATA)(self)
     }
 
     // Note that this is *untracked* and should only be used within the query

compiler/rustc_middle/src/ty/mod.rs

@@ -119,6 +119,8 @@ mod list;
 mod structural_impls;
 mod sty;
 
+pub use context::ENCODE_METADATA;
+
 // Data types
 
 pub struct ResolverOutputs {