1 files changed, 85 insertions, 0 deletions
diff --git a/gcc/rust/util/rust-mapping-common.h b/gcc/rust/util/rust-mapping-common.h
new file mode 100644
index 00000000000..c440ae98931
--- /dev/null
+++ b/gcc/rust/util/rust-mapping-common.h
@@ -0,0 +1,85 @@
+// Copyright (C) 2020-2022 Free Software Foundation, Inc.
+
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#ifndef RUST_MAPPING_COMMON
+#define RUST_MAPPING_COMMON
+
+#include "rust-system.h"
+
+namespace Rust {
+
+// refers to a Crate
+typedef uint32_t CrateNum;
+// refers to any node in the AST in current Crate
+typedef uint32_t NodeId;
+// refers to any node in the HIR for the current crate
+typedef uint32_t HirId;
+// refers to any top-level decl in HIR
+typedef uint32_t LocalDefId;
+
+struct DefId
+{
+  CrateNum crateNum;
+  LocalDefId localDefId;
+
+  bool operator== (const DefId &other) const
+  {
+    return this->crateNum == other.crateNum
+	   && this->localDefId == other.localDefId;
+  }
+
+  bool operator!= (const DefId &other) const { return !(*this == other); }
+
+  bool operator< (const DefId &other) const
+  {
+    return ((uint64_t) this->crateNum << 32 | this->localDefId)
+	   < ((uint64_t) other.crateNum << 32 | other.localDefId);
+  }
+
+  std::string as_string () const
+  {
+    std::string buf;
+    buf += std::to_string (crateNum);
+    buf += " "; // or anything else
+    buf += std::to_string (localDefId);
+    return buf;
+  }
+};
+
+#define UNKNOWN_CREATENUM ((uint32_t) (0))
+#define UNKNOWN_NODEID ((uint32_t) (0))
+#define UNKNOWN_HIRID ((uint32_t) (0))
+#define UNKNOWN_LOCAL_DEFID ((uint32_t) (0))
+#define UNKNOWN_DEFID (DefId{0, 0})
+
+} // 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