gccrs: Allow rustc_const_stable and rustc_const_unstable

gcc/rust/ChangeLog:

	* expand/rust-macro-builtins.cc
	(MacroBuiltin::builtin_transcribers):
	Add entries for "rustc_const_stable" and "rustc_const_unstable".
	* util/rust-attributes.cc
	(__definitions): Add entries for RUSTC_CONST_STABLE and
	RUSTC_CONST_UNSTABLE.
	* util/rust-attribute-values.h
	(Attributes::RUSTC_CONST_STABLE): New.
	(Attributes::RUSTC_CONST_UNSTABLE): New.

gcc/testsuite/ChangeLog:

	* rust/compile/rustc_const_stable.rs:
	Enable feature rustc_attrs, expect no errors.
	* rust/compile/rustc_const_unstable.rs: New test.

Signed-off-by: Owen Avery <powerboat9.gamer@gmail.com>

5 files changed, 15 insertions, 2 deletions

diff --git a/gcc/rust/expand/rust-macro-builtins.cc b/gcc/rust/expand/rust-macro-builtins.cc
index ed6c0e9..61b677a 100644
--- a/gcc/rust/expand/rust-macro-builtins.cc
+++ b/gcc/rust/expand/rust-macro-builtins.cc
@@ -123,6 +123,8 @@ std::unordered_map<std::string, AST::MacroTranscriberFunc>
     {"test_case", MacroBuiltin::sorry},
     {"global_allocator", MacroBuiltin::sorry},
     {"cfg_accessible", MacroBuiltin::sorry},
+    {"rustc_const_stable", MacroBuiltin::sorry},
+    {"rustc_const_unstable", MacroBuiltin::sorry},
     /* Derive builtins do not need a real transcriber, but still need one. It
        should however never be called since builtin derive macros get expanded
        differently, and benefit from knowing on what kind of items they are
diff --git a/gcc/rust/util/rust-attribute-values.h b/gcc/rust/util/rust-attribute-values.h
index e51ec07..fec73b1 100644
--- a/gcc/rust/util/rust-attribute-values.h
+++ b/gcc/rust/util/rust-attribute-values.h
@@ -53,6 +53,8 @@ public:
     = "rustc_inherit_overflow_checks";
   static constexpr auto &STABLE = "stable";
   static constexpr auto &UNSTABLE = "unstable";
+  static constexpr auto &RUSTC_CONST_STABLE = "rustc_const_stable";
+  static constexpr auto &RUSTC_CONST_UNSTABLE = "rustc_const_unstable";
 };
 } // namespace Values
 } // namespace Rust
diff --git a/gcc/rust/util/rust-attributes.cc b/gcc/rust/util/rust-attributes.cc
index aef51b7..c9e3764 100644
--- a/gcc/rust/util/rust-attributes.cc
+++ b/gcc/rust/util/rust-attributes.cc
@@ -61,7 +61,10 @@ static const BuiltinAttrDefinition __definitions[]
      {Attrs::RUSTC_DEPRECATED, STATIC_ANALYSIS},
      {Attrs::RUSTC_INHERIT_OVERFLOW_CHECKS, CODE_GENERATION},
      {Attrs::STABLE, STATIC_ANALYSIS},
-     {Attrs::UNSTABLE, STATIC_ANALYSIS}};
+     {Attrs::UNSTABLE, STATIC_ANALYSIS},
+     // assuming we keep these for static analysis
+     {Attrs::RUSTC_CONST_STABLE, STATIC_ANALYSIS},
+     {Attrs::RUSTC_CONST_UNSTABLE, STATIC_ANALYSIS}};
 
 BuiltinAttributeMappings *
 BuiltinAttributeMappings::get ()
diff --git a/gcc/testsuite/rust/compile/rustc_const_stable.rs b/gcc/testsuite/rust/compile/rustc_const_stable.rs
index 9208b1a..a45355d 100644
--- a/gcc/testsuite/rust/compile/rustc_const_stable.rs
+++ b/gcc/testsuite/rust/compile/rustc_const_stable.rs
@@ -1,2 +1,4 @@
+#![feature(rustc_attrs)]
+
 #[rustc_const_stable(feature = "const_ascii_ctype_on_intrinsics", since = "1.47.0")]
-pub fn foo() {} // { dg-error "macro not found" "" { target *-*-* } .-1 }
+pub fn foo() {}
diff --git a/gcc/testsuite/rust/compile/rustc_const_unstable.rs b/gcc/testsuite/rust/compile/rustc_const_unstable.rs
new file mode 100644
index 0000000..6cedefa
--- /dev/null
+++ b/gcc/testsuite/rust/compile/rustc_const_unstable.rs
@@ -0,0 +1,4 @@
+#![feature(rustc_attrs)]
+
+#[rustc_const_unstable(feature = "const_ascii_ctype_on_intrinsics", issue = "1234")]
+pub fn foo() {}