incr.comp.: Make the StableHashingContext mostly independent of the tcx.

5 files changed, 61 insertions, 39 deletions

diff --git a/src/librustc/ich/hcx.rs b/src/librustc/ich/hcx.rs
index 616b966cb50..136190f7573 100644
--- a/src/librustc/ich/hcx.rs
+++ b/src/librustc/ich/hcx.rs
@@ -9,11 +9,12 @@
 // except according to those terms.
 
 use hir;
-use hir::def_id::DefId;
+use hir::def_id::{DefId, DefIndex};
 use hir::map::DefPathHash;
 use ich::{self, CachingCodemapView};
 use session::config::DebugInfoLevel::NoDebugInfo;
 use ty::{self, TyCtxt, fast_reject};
+use session::Session;
 
 use std::cmp::Ord;
 use std::hash as std_hash;
@@ -42,6 +43,7 @@ thread_local!(static IGNORED_ATTR_NAMES: RefCell<FxHashSet<Symbol>> =
 /// things (e.g. each DefId/DefPath is only hashed once).
 pub struct StableHashingContext<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
     tcx: TyCtxt<'a, 'gcx, 'tcx>,
+    body_resolver: BodyResolver<'gcx>,
     hash_spans: bool,
     hash_bodies: bool,
     overflow_checks_enabled: bool,
@@ -59,6 +61,20 @@ pub enum NodeIdHashingMode {
     HashDefPath,
 }
 
+/// The BodyResolver allows to map a BodyId to the corresponding hir::Body.
+/// We could also just store a plain reference to the hir::Crate but we want
+/// to avoid that the crate is used to get untracked access to all of the HIR.
+#[derive(Clone, Copy)]
+struct BodyResolver<'hir>(&'hir hir::Crate);
+
+impl<'hir> BodyResolver<'hir> {
+    // Return a reference to the hir::Body with the given BodyId.
+    // DOES NOT DO ANY TRACKING, use carefully.
+    fn body(self, id: hir::BodyId) -> &'hir hir::Body {
+        self.0.body(id)
+    }
+}
+
 impl<'a, 'gcx, 'tcx> StableHashingContext<'a, 'gcx, 'tcx> {
 
     pub fn new(tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Self {
@@ -74,8 +90,11 @@ impl<'a, 'gcx, 'tcx> StableHashingContext<'a, 'gcx, 'tcx> {
             }
         });
 
+        let body_resolver = BodyResolver(tcx.dep_graph.with_ignore(|| tcx.hir.krate()));
+
         StableHashingContext {
             tcx,
+            body_resolver,
             caching_codemap: None,
             raw_codemap: tcx.sess.codemap(),
             hash_spans: hash_spans_initial,
@@ -85,6 +104,11 @@ impl<'a, 'gcx, 'tcx> StableHashingContext<'a, 'gcx, 'tcx> {
         }
     }
 
+    #[inline]
+    pub fn sess(&self) -> &'gcx Session {
+        self.tcx.sess
+    }
+
     pub fn force_span_hashing(mut self) -> Self {
         self.hash_spans = true;
         self
@@ -121,13 +145,13 @@ impl<'a, 'gcx, 'tcx> StableHashingContext<'a, 'gcx, 'tcx> {
     }
 
     #[inline]
-    pub fn tcx(&self) -> TyCtxt<'a, 'gcx, 'tcx> {
-        self.tcx
+    pub fn def_path_hash(&self, def_id: DefId) -> DefPathHash {
+        self.tcx.def_path_hash(def_id)
     }
 
     #[inline]
-    pub fn def_path_hash(&mut self, def_id: DefId) -> DefPathHash {
-        self.tcx.def_path_hash(def_id)
+    pub fn local_def_path_hash(&self, def_index: DefIndex) -> DefPathHash {
+        self.tcx.hir.definitions().def_path_hash(def_index)
     }
 
     #[inline]
@@ -221,6 +245,16 @@ impl<'a, 'gcx, 'lcx> StableHashingContextProvider for ty::TyCtxt<'a, 'gcx, 'lcx>
     }
 }
 
+impl<'a, 'gcx, 'tcx> HashStable<StableHashingContext<'a, 'gcx, 'tcx>> for hir::BodyId {
+    fn hash_stable<W: StableHasherResult>(&self,
+                                          hcx: &mut StableHashingContext<'a, 'gcx, 'tcx>,
+                                          hasher: &mut StableHasher<W>) {
+        if hcx.hash_bodies() {
+            hcx.body_resolver.body(*self).hash_stable(hcx, hasher);
+        }
+    }
+}
+
 impl<'a, 'gcx, 'tcx> HashStable<StableHashingContext<'a, 'gcx, 'tcx>> for hir::HirId {
     #[inline]
     fn hash_stable<W: StableHasherResult>(&self,
@@ -250,7 +284,7 @@ impl<'a, 'gcx, 'tcx> ToStableHashKey<StableHashingContext<'a, 'gcx, 'tcx>> for h
     fn to_stable_hash_key(&self,
                           hcx: &StableHashingContext<'a, 'gcx, 'tcx>)
                           -> (DefPathHash, hir::ItemLocalId) {
-        let def_path_hash = hcx.tcx().hir.definitions().def_path_hash(self.owner);
+        let def_path_hash = hcx.local_def_path_hash(self.owner);
         (def_path_hash, self.local_id)
     }
 }
@@ -378,10 +412,9 @@ pub fn hash_stable_trait_impls<'a, 'tcx, 'gcx, W, R>(
     }
 
     {
-        let tcx = hcx.tcx();
         let mut keys: AccumulateVec<[_; 8]> =
             non_blanket_impls.keys()
-                             .map(|k| (k, k.map_def(|d| tcx.def_path_hash(d))))
+                             .map(|k| (k, k.map_def(|d| hcx.def_path_hash(d))))
                              .collect();
         keys.sort_unstable_by(|&(_, ref k1), &(_, ref k2)| k1.cmp(k2));
         keys.len().hash_stable(hcx, hasher);
diff --git a/src/librustc/ich/impls_hir.rs b/src/librustc/ich/impls_hir.rs
index 3c89e10a0d2..aa4826528ec 100644
--- a/src/librustc/ich/impls_hir.rs
+++ b/src/librustc/ich/impls_hir.rs
@@ -34,7 +34,7 @@ impl<'a, 'gcx, 'tcx> ToStableHashKey<StableHashingContext<'a, 'gcx, 'tcx>> for D
 
     #[inline]
     fn to_stable_hash_key(&self, hcx: &StableHashingContext<'a, 'gcx, 'tcx>) -> DefPathHash {
-        hcx.tcx().def_path_hash(*self)
+        hcx.def_path_hash(*self)
     }
 }
 
@@ -995,16 +995,6 @@ impl<'a, 'gcx, 'tcx> HashStable<StableHashingContext<'a, 'gcx, 'tcx>> for hir::B
     }
 }
 
-impl<'a, 'gcx, 'tcx> HashStable<StableHashingContext<'a, 'gcx, 'tcx>> for hir::BodyId {
-    fn hash_stable<W: StableHasherResult>(&self,
-                                          hcx: &mut StableHashingContext<'a, 'gcx, 'tcx>,
-                                          hasher: &mut StableHasher<W>) {
-        if hcx.hash_bodies() {
-            hcx.tcx().hir.body(*self).hash_stable(hcx, hasher);
-        }
-    }
-}
-
 impl<'a, 'gcx, 'tcx> ToStableHashKey<StableHashingContext<'a, 'gcx, 'tcx>> for hir::BodyId {
     type KeyType = (DefPathHash, hir::ItemLocalId);
 
@@ -1119,7 +1109,7 @@ for hir::def_id::DefIndex {
     fn hash_stable<W: StableHasherResult>(&self,
                                           hcx: &mut StableHashingContext<'a, 'gcx, 'tcx>,
                                           hasher: &mut StableHasher<W>) {
-        hcx.tcx().hir.definitions().def_path_hash(*self).hash_stable(hcx, hasher);
+        hcx.local_def_path_hash(*self).hash_stable(hcx, hasher);
     }
 }
 
@@ -1129,7 +1119,7 @@ for hir::def_id::DefIndex {
 
     #[inline]
     fn to_stable_hash_key(&self, hcx: &StableHashingContext<'a, 'gcx, 'tcx>) -> DefPathHash {
-         hcx.tcx().hir.definitions().def_path_hash(*self)
+         hcx.local_def_path_hash(*self)
     }
 }
 
diff --git a/src/librustc/ich/impls_syntax.rs b/src/librustc/ich/impls_syntax.rs
index 4e3caca2b61..6bcbce4b693 100644
--- a/src/librustc/ich/impls_syntax.rs
+++ b/src/librustc/ich/impls_syntax.rs
@@ -324,11 +324,11 @@ fn hash_token<'a, 'gcx, 'tcx, W: StableHasherResult>(token: &token::Token,
             //            in a stable way, in addition to the HIR.
             //            Since this is hardly used anywhere, just emit a
             //            warning for now.
-            if hcx.tcx().sess.opts.debugging_opts.incremental.is_some() {
+            if hcx.sess().opts.debugging_opts.incremental.is_some() {
                 let msg = format!("Quasi-quoting might make incremental \
                                    compilation very inefficient: {:?}",
                                   non_terminal);
-                hcx.tcx().sess.span_warn(error_reporting_span, &msg[..]);
+                hcx.sess().span_warn(error_reporting_span, &msg[..]);
             }
 
             std_hash::Hash::hash(non_terminal, hasher);
diff --git a/src/librustc/ty/context.rs b/src/librustc/ty/context.rs
index 0ea466a1bbc..61cd5db9a19 100644
--- a/src/librustc/ty/context.rs
+++ b/src/librustc/ty/context.rs
@@ -736,9 +736,9 @@ impl<'a, 'gcx, 'tcx> HashStable<StableHashingContext<'a, 'gcx, 'tcx>> for Typeck
                     krate: local_id_root.krate,
                     index: closure_expr_id,
                 };
-                (hcx.tcx().def_path_hash(var_owner_def_id),
+                (hcx.def_path_hash(var_owner_def_id),
                  var_id.local_id,
-                 hcx.tcx().def_path_hash(closure_def_id))
+                 hcx.def_path_hash(closure_def_id))
             });
 
             closure_tys.hash_stable(hcx, hasher);
diff --git a/src/librustc_incremental/calculate_svh/mod.rs b/src/librustc_incremental/calculate_svh/mod.rs
index d8e201d3acd..60e1f238f44 100644
--- a/src/librustc_incremental/calculate_svh/mod.rs
+++ b/src/librustc_incremental/calculate_svh/mod.rs
@@ -90,6 +90,7 @@ impl<'a> ::std::ops::Index<&'a DepNode> for IncrementalHashesMap {
 }
 
 struct ComputeItemHashesVisitor<'a, 'tcx: 'a> {
+    tcx: TyCtxt<'a, 'tcx, 'tcx>,
     hcx: StableHashingContext<'a, 'tcx, 'tcx>,
     hashes: IncrementalHashesMap,
 }
@@ -101,14 +102,14 @@ impl<'a, 'tcx: 'a> ComputeItemHashesVisitor<'a, 'tcx> {
                                               item_like: T)
         where T: HashStable<StableHashingContext<'a, 'tcx, 'tcx>>
     {
-        if !hash_bodies && !self.hcx.tcx().sess.opts.build_dep_graph() {
+        if !hash_bodies && !self.tcx.sess.opts.build_dep_graph() {
             // If we just need the hashes in order to compute the SVH, we don't
             // need have two hashes per item. Just the one containing also the
             // item's body is sufficient.
             return
         }
 
-        let def_path_hash = self.hcx.tcx().hir.definitions().def_path_hash(def_index);
+        let def_path_hash = self.hcx.local_def_path_hash(def_index);
 
         let mut hasher = IchHasher::new();
         self.hcx.while_hashing_hir_bodies(hash_bodies, |hcx| {
@@ -125,14 +126,12 @@ impl<'a, 'tcx: 'a> ComputeItemHashesVisitor<'a, 'tcx> {
         debug!("calculate_def_hash: dep_node={:?} hash={:?}", dep_node, item_hash);
         self.hashes.insert(dep_node, item_hash);
 
-        let tcx = self.hcx.tcx();
         let bytes_hashed =
-            tcx.sess.perf_stats.incr_comp_bytes_hashed.get() +
-            bytes_hashed;
-        tcx.sess.perf_stats.incr_comp_bytes_hashed.set(bytes_hashed);
+            self.tcx.sess.perf_stats.incr_comp_bytes_hashed.get() + bytes_hashed;
+        self.tcx.sess.perf_stats.incr_comp_bytes_hashed.set(bytes_hashed);
 
         if hash_bodies {
-            let in_scope_traits_map = tcx.in_scope_traits_map(def_index);
+            let in_scope_traits_map = self.tcx.in_scope_traits_map(def_index);
             let mut hasher = IchHasher::new();
             in_scope_traits_map.hash_stable(&mut self.hcx, &mut hasher);
             let dep_node = def_path_hash.to_dep_node(DepKind::InScopeTraits);
@@ -141,12 +140,11 @@ impl<'a, 'tcx: 'a> ComputeItemHashesVisitor<'a, 'tcx> {
     }
 
     fn compute_crate_hash(&mut self) {
-        let tcx = self.hcx.tcx();
-        let krate = tcx.hir.krate();
+        let krate = self.tcx.hir.krate();
 
         let mut crate_state = IchHasher::new();
 
-        let crate_disambiguator = tcx.sess.local_crate_disambiguator();
+        let crate_disambiguator = self.tcx.sess.local_crate_disambiguator();
         "crate_disambiguator".hash(&mut crate_state);
         crate_disambiguator.as_str().len().hash(&mut crate_state);
         crate_disambiguator.as_str().hash(&mut crate_state);
@@ -221,7 +219,7 @@ impl<'a, 'tcx: 'a> ComputeItemHashesVisitor<'a, 'tcx> {
 
     fn compute_and_store_ich_for_trait_impls(&mut self, krate: &'tcx hir::Crate)
     {
-        let tcx = self.hcx.tcx();
+        let tcx = self.tcx;
 
         let mut impls: Vec<(DefPathHash, Fingerprint)> = krate
             .trait_impls
@@ -266,7 +264,7 @@ impl<'a, 'tcx: 'a> ComputeItemHashesVisitor<'a, 'tcx> {
 
 impl<'a, 'tcx: 'a> ItemLikeVisitor<'tcx> for ComputeItemHashesVisitor<'a, 'tcx> {
     fn visit_item(&mut self, item: &'tcx hir::Item) {
-        let def_index = self.hcx.tcx().hir.local_def_id(item.id).index;
+        let def_index = self.tcx.hir.local_def_id(item.id).index;
         self.compute_and_store_ich_for_item_like(def_index,
                                                  false,
                                                  item);
@@ -276,7 +274,7 @@ impl<'a, 'tcx: 'a> ItemLikeVisitor<'tcx> for ComputeItemHashesVisitor<'a, 'tcx>
     }
 
     fn visit_trait_item(&mut self, item: &'tcx hir::TraitItem) {
-        let def_index = self.hcx.tcx().hir.local_def_id(item.id).index;
+        let def_index = self.tcx.hir.local_def_id(item.id).index;
         self.compute_and_store_ich_for_item_like(def_index,
                                                  false,
                                                  item);
@@ -286,7 +284,7 @@ impl<'a, 'tcx: 'a> ItemLikeVisitor<'tcx> for ComputeItemHashesVisitor<'a, 'tcx>
     }
 
     fn visit_impl_item(&mut self, item: &'tcx hir::ImplItem) {
-        let def_index = self.hcx.tcx().hir.local_def_id(item.id).index;
+        let def_index = self.tcx.hir.local_def_id(item.id).index;
         self.compute_and_store_ich_for_item_like(def_index,
                                                  false,
                                                  item);
@@ -304,6 +302,7 @@ pub fn compute_incremental_hashes_map<'a, 'tcx: 'a>(tcx: TyCtxt<'a, 'tcx, 'tcx>)
     let krate = tcx.hir.krate();
 
     let mut visitor = ComputeItemHashesVisitor {
+        tcx,
         hcx: StableHashingContext::new(tcx),
         hashes: IncrementalHashesMap::new(),
     };