[gcc/devel/rust/master] privacy: Keep DefIds in reachability map instead

[gcc/devel/rust/master] privacy: Keep DefIds in reachability map instead

[Thomas Schwinge]

https://gcc.gnu.org/g:ece3809c505c8a474b81f6c00fbe6fc83718a2cf

commit ece3809c505c8a474b81f6c00fbe6fc83718a2cf
Author: Arthur Cohen <arthur.cohen@embecosm.com>
Date:   Tue Apr 12 10:19:11 2022 +0200

    privacy: Keep DefIds in reachability map instead
    
    This commit also specialized `std::hash<DefId>` to be able to use it as
    key in {unordered_}maps

Diff:
---
 gcc/rust/privacy/rust-privacy-ctx.cc |  9 +++++----
 gcc/rust/privacy/rust-privacy-ctx.h  |  2 +-
 gcc/rust/util/rust-mapping-common.h  | 13 +++++++++++++
 3 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/gcc/rust/privacy/rust-privacy-ctx.cc b/gcc/rust/privacy/rust-privacy-ctx.cc
index 629944a390c..9ebc86988e9 100644
--- a/gcc/rust/privacy/rust-privacy-ctx.cc
+++ b/gcc/rust/privacy/rust-privacy-ctx.cc
@@ -24,7 +24,7 @@ namespace Privacy {
 
 static ReachLevel
 insert_if_higher (ReachLevel new_level,
-		  std::unordered_map<HirId, ReachLevel>::iterator &existing)
+		  std::unordered_map<DefId, ReachLevel>::iterator &existing)
 {
   if (new_level > existing->second)
     existing->second = new_level;
@@ -36,18 +36,19 @@ ReachLevel
 PrivacyContext::update_reachability (const Analysis::NodeMapping &mapping,
 				     ReachLevel reach)
 {
-  auto existing_reach = reachability_map.find (mapping.get_hirid ());
+  auto def_id = mapping.get_defid ();
+  auto existing_reach = reachability_map.find (def_id);
   if (existing_reach != reachability_map.end ())
     return insert_if_higher (reach, existing_reach);
 
-  reachability_map.insert ({mapping.get_hirid (), reach});
+  reachability_map.insert ({def_id, reach});
   return reach;
 }
 
 const ReachLevel *
 PrivacyContext::lookup_reachability (const Analysis::NodeMapping &mapping)
 {
-  auto existing_reach = reachability_map.find (mapping.get_hirid ());
+  auto existing_reach = reachability_map.find (mapping.get_defid ());
   if (existing_reach == reachability_map.end ())
     return nullptr;
 
diff --git a/gcc/rust/privacy/rust-privacy-ctx.h b/gcc/rust/privacy/rust-privacy-ctx.h
index 7626df300e7..52d790edf63 100644
--- a/gcc/rust/privacy/rust-privacy-ctx.h
+++ b/gcc/rust/privacy/rust-privacy-ctx.h
@@ -64,7 +64,7 @@ public:
   const ReachLevel *lookup_reachability (const Analysis::NodeMapping &mapping);
 
 private:
-  std::unordered_map<HirId, ReachLevel> reachability_map;
+  std::unordered_map<DefId, ReachLevel> reachability_map;
 };
 } // namespace Privacy
 } // namespace Rust
diff --git a/gcc/rust/util/rust-mapping-common.h b/gcc/rust/util/rust-mapping-common.h
index 27faa7f4254..c440ae98931 100644
--- a/gcc/rust/util/rust-mapping-common.h
+++ b/gcc/rust/util/rust-mapping-common.h
@@ -69,4 +69,17 @@ struct DefId
 
 } // namespace Rust
 
+namespace std {
+template <> struct hash<Rust::DefId>
+{
+  size_t operator() (const Rust::DefId &id) const noexcept
+  {
+    // TODO: Check if we can improve performance by having a better hash
+    // algorithm for `DefId`s
+    return hash<uint32_t> () (hash<uint32_t> () (id.crateNum)
+			      + hash<uint32_t> () (id.localDefId));
+  }
+};
+} // namespace std
+
 #endif // RUST_MAPPING_COMMON