Merge #953

953: Refactor lang item mappings r=philberty a=philberty

This refactors how we find our lang items so that during HIR lowering
we have a generic outer attributes handler on Items. The old code only
done lang item mappings during the type check pass and assumed all
lang items are Traits which is not the case. To implement slices range
syntax actually map to structs within libcore/ops/range.rs which have
lang items on structs. This means we can have lang items on any Item.

Co-authored-by: Philip Herron <philip.herron@embecosm.com>

1 files changed, 61 insertions, 0 deletions

diff --git a/gcc/rust/util/rust-attributes.cc b/gcc/rust/util/rust-attributes.cc
new file mode 100644
index 0000000..3809ad7
--- /dev/null
+++ b/gcc/rust/util/rust-attributes.cc
@@ -0,0 +1,61 @@
+// 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/>.
+
+#include "rust-attributes.h"
+
+namespace Rust {
+namespace Analysis {
+
+// https://doc.rust-lang.org/stable/nightly-rustc/src/rustc_feature/builtin_attrs.rs.html#256
+static const BuiltinAttrDefinition __definitions[] = {
+  {"inline", CODE_GENERATION}, {"cfg", EXPANSION},     {"cfg_attr", EXPANSION},
+  {"allow", STATIC_ANALYSIS},  {"lang", HIR_LOWERING},
+};
+
+BuiltinAttributeMappings *
+BuiltinAttributeMappings::get ()
+{
+  static BuiltinAttributeMappings *instance = nullptr;
+  if (instance == nullptr)
+    instance = new BuiltinAttributeMappings ();
+
+  return instance;
+}
+
+const BuiltinAttrDefinition &
+BuiltinAttributeMappings::lookup_builtin (const std::string &attr_name) const
+{
+  auto it = mappings.find (attr_name);
+  if (it == mappings.end ())
+    return BuiltinAttrDefinition::error_node ();
+
+  return it->second;
+}
+
+BuiltinAttributeMappings::BuiltinAttributeMappings ()
+{
+  size_t ndefinitions = sizeof (__definitions) / sizeof (BuiltinAttrDefinition);
+  for (size_t i = 0; i < ndefinitions; i++)
+    {
+      const BuiltinAttrDefinition &def = __definitions[i];
+      mappings.insert ({def.name, def});
+    }
+}
+
+} // namespace Analysis
+} // namespace Rust