From 279b6df1f2355b0b9af5993f38fd9524d74c320d Mon Sep 17 00:00:00 2001
From: Michael Woerister <michaelwoerister@posteo>
Date: Wed, 15 Nov 2017 14:18:00 +0100
Subject: [PATCH] incr.comp.: Refactor query cache serialization to be more
 re-usable.

---
 src/librustc/ty/context.rs            |  2 +-
 src/librustc/ty/maps/on_disk_cache.rs | 53 ++++++++++++++++++---------
 src/librustc/ty/maps/plumbing.rs      | 14 ++++++-
 3 files changed, 49 insertions(+), 20 deletions(-)

diff --git a/src/librustc/ty/context.rs b/src/librustc/ty/context.rs
index 512860a02b0..1395f37722e 100644
--- a/src/librustc/ty/context.rs
+++ b/src/librustc/ty/context.rs
@@ -1313,7 +1313,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
                                            -> Result<(), E::Error>
         where E: ty::codec::TyEncoder
     {
-        self.on_disk_query_result_cache.serialize(self, self.cstore, encoder)
+        self.on_disk_query_result_cache.serialize(self.global_tcx(), self.cstore, encoder)
     }
 
 }
diff --git a/src/librustc/ty/maps/on_disk_cache.rs b/src/librustc/ty/maps/on_disk_cache.rs
index d325d1437fc..98727b5d10d 100644
--- a/src/librustc/ty/maps/on_disk_cache.rs
+++ b/src/librustc/ty/maps/on_disk_cache.rs
@@ -32,7 +32,6 @@ use syntax_pos::{BytePos, Span, NO_EXPANSION, DUMMY_SP};
 use ty;
 use ty::codec::{self as ty_codec, TyDecoder, TyEncoder};
 use ty::context::TyCtxt;
-use ty::maps::config::QueryDescription;
 use ty::subst::Substs;
 
 // Some magic values used for verifying that encoding and decoding. These are
@@ -162,11 +161,11 @@ impl<'sess> OnDiskCache<'sess> {
         }
     }
 
-    pub fn serialize<'a, 'gcx, 'lcx, E>(&self,
-                                        tcx: TyCtxt<'a, 'gcx, 'lcx>,
-                                        cstore: &CrateStore,
-                                        encoder: &mut E)
-                                        -> Result<(), E::Error>
+    pub fn serialize<'a, 'tcx, E>(&self,
+                                  tcx: TyCtxt<'a, 'tcx, 'tcx>,
+                                  cstore: &CrateStore,
+                                  encoder: &mut E)
+                                  -> Result<(), E::Error>
         where E: ty_codec::TyEncoder
      {
         // Serializing the DepGraph should not modify it:
@@ -232,19 +231,13 @@ impl<'sess> OnDiskCache<'sess> {
         // Encode query results
         let mut query_result_index = EncodedQueryResultIndex::new();
 
-        // Encode TypeckTables
-        for (def_id, entry) in tcx.maps.typeck_tables_of.borrow().map.iter() {
-            if ty::maps::queries::typeck_tables_of::cache_on_disk(*def_id) {
-                let dep_node = SerializedDepNodeIndex::new(entry.index.index());
+        {
+            use ty::maps::queries::*;
+            let enc = &mut encoder;
+            let qri = &mut query_result_index;
 
-                // Record position of the cache entry
-                query_result_index.push((dep_node, encoder.position()));
-
-                // Encode the type check tables with the SerializedDepNodeIndex
-                // as tag.
-                let typeck_tables: &ty::TypeckTables<'gcx> = &entry.value;
-                encoder.encode_tagged(dep_node, typeck_tables)?;
-            }
+            // Encode TypeckTables
+            encode_query_results::<typeck_tables_of, _>(tcx, enc, qri)?;
         }
 
         // Encode query result index
@@ -842,3 +835,27 @@ for CacheDecoder<'a, 'tcx, 'x> {
         Ok(IntEncodedWithFixedSize(value))
     }
 }
+
+fn encode_query_results<'x, 'a, 'tcx, Q, E>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
+                                            encoder: &mut CacheEncoder<'x, 'tcx, E>,
+                                            query_result_index: &mut EncodedQueryResultIndex)
+                                            -> Result<(), E::Error>
+    where Q: super::plumbing::GetCacheInternal<'tcx>,
+          E: 'x + TyEncoder,
+          Q::Value: Encodable,
+{
+    for (key, entry) in Q::get_cache_internal(tcx).map.iter() {
+        if Q::cache_on_disk(key.clone()) {
+            let dep_node = SerializedDepNodeIndex::new(entry.index.index());
+
+            // Record position of the cache entry
+            query_result_index.push((dep_node, encoder.position()));
+
+            // Encode the type check tables with the SerializedDepNodeIndex
+            // as tag.
+            encoder.encode_tagged(dep_node, &entry.value)?;
+        }
+    }
+
+    Ok(())
+}
diff --git a/src/librustc/ty/maps/plumbing.rs b/src/librustc/ty/maps/plumbing.rs
index 2f8f724edad..1ca8fc6eb48 100644
--- a/src/librustc/ty/maps/plumbing.rs
+++ b/src/librustc/ty/maps/plumbing.rs
@@ -20,7 +20,7 @@ use ty::maps::config::QueryDescription;
 use ty::item_path;
 
 use rustc_data_structures::fx::{FxHashMap};
-use std::cell::RefMut;
+use std::cell::{Ref, RefMut};
 use std::marker::PhantomData;
 use std::mem;
 use syntax_pos::Span;
@@ -55,6 +55,11 @@ impl<'tcx, M: QueryDescription<'tcx>> QueryMap<'tcx, M> {
     }
 }
 
+pub(super) trait GetCacheInternal<'tcx>: QueryDescription<'tcx> + Sized {
+    fn get_cache_internal<'a>(tcx: TyCtxt<'a, 'tcx, 'tcx>)
+                              -> Ref<'a, QueryMap<'tcx, Self>>;
+}
+
 pub(super) struct CycleError<'a, 'tcx: 'a> {
     span: Span,
     cycle: RefMut<'a, [(Span, Query<'tcx>)]>,
@@ -242,6 +247,13 @@ macro_rules! define_maps {
             type Value = $V;
         }
 
+        impl<$tcx> GetCacheInternal<$tcx> for queries::$name<$tcx> {
+            fn get_cache_internal<'a>(tcx: TyCtxt<'a, $tcx, $tcx>)
+                                      -> ::std::cell::Ref<'a, QueryMap<$tcx, Self>> {
+                tcx.maps.$name.borrow()
+            }
+        }
+
         impl<'a, $tcx, 'lcx> queries::$name<$tcx> {
 
             #[allow(unused)]