Move CrateStore::expn_hash_to_expn_id to a hook

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

@@ -21,7 +21,7 @@
 use rustc_middle::util::Providers;
 use rustc_session::cstore::{CrateStore, ExternCrate};
 use rustc_session::{Session, StableCrateId};
-use rustc_span::hygiene::{ExpnHash, ExpnId};
+use rustc_span::hygiene::ExpnId;
 use rustc_span::symbol::{kw, Symbol};
 use rustc_span::Span;
 
@@ -655,19 +655,13 @@ fn def_path_hash_to_def_id(&self, cnum: CrateNum, hash: DefPathHash) -> DefId {
         let def_index = self.get_crate_data(cnum).def_path_hash_to_def_index(hash);
         DefId { krate: cnum, index: def_index }
     }
-
-    fn expn_hash_to_expn_id(
-        &self,
-        sess: &Session,
-        cnum: CrateNum,
-        index_guess: u32,
-        hash: ExpnHash,
-    ) -> ExpnId {
-        self.get_crate_data(cnum).expn_hash_to_expn_id(sess, index_guess, hash)
-    }
 }
 
 fn provide_cstore_hooks(providers: &mut Providers) {
+    providers.hooks.expn_hash_to_expn_id = |tcx, cnum, index_guess, hash| {
+        let cstore = CStore::from_tcx(tcx.tcx);
+        cstore.get_crate_data(cnum).expn_hash_to_expn_id(tcx.sess, index_guess, hash)
+    };
     providers.hooks.import_source_files = |tcx, cnum| {
         let cstore = CStore::from_tcx(tcx.tcx);
         let cdata = cstore.get_crate_data(cnum);

compiler/rustc_middle/src/hooks/mod.rs

@@ -7,7 +7,7 @@
 use crate::query::TyCtxtAt;
 use crate::ty::{Ty, TyCtxt};
 use rustc_span::def_id::{CrateNum, LocalDefId};
-use rustc_span::DUMMY_SP;
+use rustc_span::{ExpnHash, ExpnId, DUMMY_SP};
 
 macro_rules! declare_hooks {
     ($($(#[$attr:meta])*hook $name:ident($($arg:ident: $K:ty),*) -> $V:ty;)*) => {
@@ -88,4 +88,10 @@ fn clone(&self) -> Self { *self }
     /// that crate's metadata - however, the incr comp cache needs
     /// to trigger this manually when decoding a foreign `Span`
     hook import_source_files(key: CrateNum) -> ();
+
+    hook expn_hash_to_expn_id(
+        cnum: CrateNum,
+        index_guess: u32,
+        hash: ExpnHash
+    ) -> ExpnId;
 }

compiler/rustc_middle/src/query/on_disk_cache.rs

@@ -632,12 +632,7 @@ fn decode_expn_id(&mut self) -> ExpnId {
             expn_id
         } else {
             let index_guess = self.foreign_expn_data[&hash];
-            self.tcx.cstore_untracked().expn_hash_to_expn_id(
-                self.tcx.sess,
-                krate,
-                index_guess,
-                hash,
-            )
+            self.tcx.expn_hash_to_expn_id(krate, index_guess, hash)
         };
 
         debug_assert_eq!(expn_id.krate, krate);

compiler/rustc_session/src/cstore.rs

@@ -4,12 +4,10 @@
 
 use crate::search_paths::PathKind;
 use crate::utils::NativeLibKind;
-use crate::Session;
 use rustc_ast as ast;
 use rustc_data_structures::sync::{self, AppendOnlyIndexVec, FreezeLock};
 use rustc_hir::def_id::{CrateNum, DefId, LocalDefId, StableCrateId, LOCAL_CRATE};
 use rustc_hir::definitions::{DefKey, DefPath, DefPathHash, Definitions};
-use rustc_span::hygiene::{ExpnHash, ExpnId};
 use rustc_span::symbol::Symbol;
 use rustc_span::Span;
 use rustc_target::spec::abi::Abi;
@@ -223,13 +221,6 @@ pub trait CrateStore: std::fmt::Debug {
 
     /// Fetch a DefId from a DefPathHash for a foreign crate.
     fn def_path_hash_to_def_id(&self, cnum: CrateNum, hash: DefPathHash) -> DefId;
-    fn expn_hash_to_expn_id(
-        &self,
-        sess: &Session,
-        cnum: CrateNum,
-        index_guess: u32,
-        hash: ExpnHash,
-    ) -> ExpnId;
 }
 
 pub type CrateStoreDyn = dyn CrateStore + sync::DynSync + sync::DynSend;