Build DefPathHash->DefId table when incr.comp. is enabled

6 files changed, 77 insertions, 4 deletions

diff --git a/src/librustc/hir/map/definitions.rs b/src/librustc/hir/map/definitions.rs
index 7f91e8e0c30..745af53e7a3 100644
--- a/src/librustc/hir/map/definitions.rs
+++ b/src/librustc/hir/map/definitions.rs
@@ -126,6 +126,30 @@ impl DefPathTable {
 
         Some(index)
     }
+
+    pub fn add_def_path_hashes_to(&self,
+                                  cnum: CrateNum,
+                                  out: &mut FxHashMap<DefPathHash, DefId>) {
+        for address_space in &[DefIndexAddressSpace::Low, DefIndexAddressSpace::High] {
+            let start_index = address_space.start();
+            out.extend(
+                (&self.def_path_hashes[address_space.index()])
+                    .iter()
+                    .enumerate()
+                    .map(|(index, &hash)| {
+                        let def_id = DefId {
+                            krate: cnum,
+                            index: DefIndex::new(index + start_index),
+                        };
+                        (hash, def_id)
+                    })
+            );
+        }
+    }
+
+    pub fn size(&self) -> usize {
+        self.key_to_index.len()
+    }
 }
 
 
diff --git a/src/librustc/middle/cstore.rs b/src/librustc/middle/cstore.rs
index 55a6de62732..71b066c6688 100644
--- a/src/librustc/middle/cstore.rs
+++ b/src/librustc/middle/cstore.rs
@@ -26,7 +26,8 @@ use hir::def;
 use dep_graph::DepNode;
 use hir::def_id::{CrateNum, DefId, DefIndex};
 use hir::map as hir_map;
-use hir::map::definitions::{Definitions, DefKey, DisambiguatedDefPathData};
+use hir::map::definitions::{Definitions, DefKey, DisambiguatedDefPathData,
+                            DefPathTable};
 use hir::svh::Svh;
 use ich;
 use middle::lang_items;
@@ -282,6 +283,7 @@ pub trait CrateStore {
     fn def_key(&self, def: DefId) -> DefKey;
     fn def_path(&self, def: DefId) -> hir_map::DefPath;
     fn def_path_hash(&self, def: DefId) -> hir_map::DefPathHash;
+    fn def_path_table(&self, cnum: CrateNum) -> Rc<DefPathTable>;
     fn struct_field_names(&self, def: DefId) -> Vec<ast::Name>;
     fn item_children(&self, did: DefId) -> Vec<def::Export>;
     fn load_macro(&self, did: DefId, sess: &Session) -> LoadedMacro;
@@ -415,6 +417,9 @@ impl CrateStore for DummyCrateStore {
     fn def_path_hash(&self, def: DefId) -> hir_map::DefPathHash {
         bug!("def_path_hash")
     }
+    fn def_path_table(&self, cnum: CrateNum) -> Rc<DefPathTable> {
+        bug!("def_path_table")
+    }
     fn struct_field_names(&self, def: DefId) -> Vec<ast::Name> { bug!("struct_field_names") }
     fn item_children(&self, did: DefId) -> Vec<def::Export> { bug!("item_children") }
     fn load_macro(&self, did: DefId, sess: &Session) -> LoadedMacro { bug!("load_macro") }
diff --git a/src/librustc/ty/context.rs b/src/librustc/ty/context.rs
index 7316d45dc21..17e06571394 100644
--- a/src/librustc/ty/context.rs
+++ b/src/librustc/ty/context.rs
@@ -18,7 +18,7 @@ use hir::TraitMap;
 use hir::def::{Def, ExportMap};
 use hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
 use hir::map as hir_map;
-use hir::map::DisambiguatedDefPathData;
+use hir::map::{DisambiguatedDefPathData, DefPathHash};
 use middle::free_region::FreeRegionMap;
 use middle::lang_items;
 use middle::resolve_lifetime;
@@ -448,6 +448,10 @@ pub struct GlobalCtxt<'tcx> {
 
     pub hir: hir_map::Map<'tcx>,
 
+    /// A map from DefPathHash -> DefId. Includes DefIds from the local crate
+    /// as well as all upstream crates. Only populated in incremental mode.
+    pub def_path_hash_to_def_id: Option<FxHashMap<DefPathHash, DefId>>,
+
     pub maps: maps::Maps<'tcx>,
 
     pub mir_passes: Rc<Passes>,
@@ -676,6 +680,40 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         let max_cnum = s.cstore.crates().iter().map(|c| c.as_usize()).max().unwrap_or(0);
         let mut providers = IndexVec::from_elem_n(extern_providers, max_cnum + 1);
         providers[LOCAL_CRATE] = local_providers;
+
+        let def_path_hash_to_def_id = if s.opts.build_dep_graph() {
+            let upstream_def_path_tables: Vec<(CrateNum, Rc<_>)> = s
+                .cstore
+                .crates()
+                .iter()
+                .map(|&cnum| (cnum, s.cstore.def_path_table(cnum)))
+                .collect();
+
+            let def_path_tables = || {
+                upstream_def_path_tables
+                    .iter()
+                    .map(|&(cnum, ref rc)| (cnum, &**rc))
+                    .chain(iter::once((LOCAL_CRATE, hir.definitions().def_path_table())))
+            };
+
+            // Precompute the capacity of the hashmap so we don't have to
+            // re-allocate when populating it.
+            let capacity = def_path_tables().map(|(_, t)| t.size()).sum::<usize>();
+
+            let mut map: FxHashMap<_, _> = FxHashMap::with_capacity_and_hasher(
+                capacity,
+                ::std::default::Default::default()
+            );
+
+            for (cnum, def_path_table) in def_path_tables() {
+                def_path_table.add_def_path_hashes_to(cnum, &mut map);
+            }
+
+            Some(map)
+        } else {
+            None
+        };
+
         tls::enter_global(GlobalCtxt {
             sess: s,
             trans_trait_caches: traits::trans::TransTraitCaches::new(dep_graph.clone()),
@@ -689,6 +727,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
             export_map: resolutions.export_map,
             fulfilled_predicates: RefCell::new(fulfilled_predicates),
             hir: hir,
+            def_path_hash_to_def_id: def_path_hash_to_def_id,
             maps: maps::Maps::new(providers),
             mir_passes,
             freevars: RefCell::new(resolutions.freevars),
diff --git a/src/librustc_metadata/creader.rs b/src/librustc_metadata/creader.rs
index ec6947b4a48..51f152991fd 100644
--- a/src/librustc_metadata/creader.rs
+++ b/src/librustc_metadata/creader.rs
@@ -326,7 +326,7 @@ impl<'a> CrateLoader<'a> {
         let mut cmeta = cstore::CrateMetadata {
             name: name,
             extern_crate: Cell::new(None),
-            def_path_table: def_path_table,
+            def_path_table: Rc::new(def_path_table),
             exported_symbols: exported_symbols,
             trait_impls: trait_impls,
             proc_macros: crate_root.macro_derive_registrar.map(|_| {
diff --git a/src/librustc_metadata/cstore.rs b/src/librustc_metadata/cstore.rs
index 64fccb0314e..5066b927c11 100644
--- a/src/librustc_metadata/cstore.rs
+++ b/src/librustc_metadata/cstore.rs
@@ -76,7 +76,7 @@ pub struct CrateMetadata {
     /// hashmap, which gives the reverse mapping.  This allows us to
     /// quickly retrace a `DefPath`, which is needed for incremental
     /// compilation support.
-    pub def_path_table: DefPathTable,
+    pub def_path_table: Rc<DefPathTable>,
 
     pub exported_symbols: Tracked<FxHashSet<DefIndex>>,
 
diff --git a/src/librustc_metadata/cstore_impl.rs b/src/librustc_metadata/cstore_impl.rs
index c6695ebc4bf..dcc55846b53 100644
--- a/src/librustc_metadata/cstore_impl.rs
+++ b/src/librustc_metadata/cstore_impl.rs
@@ -25,6 +25,7 @@ use rustc::hir::def_id::{CrateNum, DefId, DefIndex, CRATE_DEF_INDEX, LOCAL_CRATE
 
 use rustc::dep_graph::{DepNode, GlobalMetaDataKind};
 use rustc::hir::map::{DefKey, DefPath, DisambiguatedDefPathData, DefPathHash};
+use rustc::hir::map::definitions::DefPathTable;
 use rustc::util::nodemap::{NodeSet, DefIdMap};
 use rustc_back::PanicStrategy;
 
@@ -337,6 +338,10 @@ impl CrateStore for cstore::CStore {
         self.get_crate_data(def.krate).def_path_hash(def.index)
     }
 
+    fn def_path_table(&self, cnum: CrateNum) -> Rc<DefPathTable> {
+        self.get_crate_data(cnum).def_path_table.clone()
+    }
+
     fn struct_field_names(&self, def: DefId) -> Vec<ast::Name>
     {
         self.dep_graph.read(DepNode::MetaData(def));