From: Arthur Cohen <arthur.cohen@embecosm.com>
Date: Thu, 1 Jun 2023 14:23:27 +0000 (+0200)
Subject: gccrs: derive: Add dummy builtin transcriber for builtin derive macros.
X-Git-Tag: basepoints/gcc-15~2498
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=446c19201459ed73bc100b4844e8ecccee5bfe2e;p=thirdparty%2Fgcc.git

gccrs: derive: Add dummy builtin transcriber for builtin derive macros.

Fixes #2257.

Derive builtins do not need a real transcriber, but still need one. It
will however never be called since builtin derive macros get expanded
differently, and benefit from knowing on what kind of items they are
applied (struct, enums, unions) rather than receiving a list of tokens
like regular builtin macros.

gcc/rust/ChangeLog:

	* expand/rust-macro-builtins.cc (MacroBuiltin::dummy): New function.
	* expand/rust-macro-builtins.h: Declare it.

gcc/testsuite/ChangeLog:

	* rust/compile/derive_macro7.rs: New test.
---

diff --git a/gcc/rust/expand/rust-macro-builtins.cc b/gcc/rust/expand/rust-macro-builtins.cc
index f4577503c25e..33b813c45940 100644
--- a/gcc/rust/expand/rust-macro-builtins.cc
+++ b/gcc/rust/expand/rust-macro-builtins.cc
@@ -105,6 +105,22 @@ std::unordered_map<
     {"test_case", MacroBuiltin::sorry},
     {"global_allocator", MacroBuiltin::sorry},
     {"cfg_accessible", MacroBuiltin::sorry},
+    /* Derive builtins do not need a real transcriber, but still need one. It
+       will however never be called since builtin derive macros get expanded
+       differently, and benefit from knowing on what kind of items they are
+       applied (struct, enums, unions) rather than receiving a list of tokens
+       like regular builtin macros */
+    {"RustcEncodable", MacroBuiltin::proc_macro_builtin},
+    {"RustcDecodable", MacroBuiltin::proc_macro_builtin},
+    {"Clone", MacroBuiltin::proc_macro_builtin},
+    {"Copy", MacroBuiltin::proc_macro_builtin},
+    {"Debug", MacroBuiltin::proc_macro_builtin},
+    {"Default", MacroBuiltin::proc_macro_builtin},
+    {"Eq", MacroBuiltin::proc_macro_builtin},
+    {"PartialEq", MacroBuiltin::proc_macro_builtin},
+    {"Ord", MacroBuiltin::proc_macro_builtin},
+    {"PartialOrd", MacroBuiltin::proc_macro_builtin},
+    {"Hash", MacroBuiltin::proc_macro_builtin},
 };
 
 // FIXME: This should return an Optional
@@ -932,4 +948,11 @@ MacroBuiltin::sorry (Location invoc_locus, AST::MacroInvocData &invoc)
   return AST::Fragment::create_error ();
 }
 
+AST::Fragment
+MacroBuiltin::proc_macro_builtin (Location, AST::MacroInvocData &)
+{
+  // nothing to do!
+  return AST::Fragment::create_error ();
+}
+
 } // namespace Rust
diff --git a/gcc/rust/expand/rust-macro-builtins.h b/gcc/rust/expand/rust-macro-builtins.h
index 0d8c4dba2dc1..3ad10a33920e 100644
--- a/gcc/rust/expand/rust-macro-builtins.h
+++ b/gcc/rust/expand/rust-macro-builtins.h
@@ -159,6 +159,10 @@ public:
 				     AST::MacroInvocData &invoc);
 
   static AST::Fragment sorry (Location invoc_locus, AST::MacroInvocData &invoc);
+
+  /* Builtin procedural macros do not work directly on tokens, but still need an
+   * empty builtin transcriber to be considered proper builtin macros */
+  static AST::Fragment proc_macro_builtin (Location, AST::MacroInvocData &);
 };
 } // namespace Rust
 
diff --git a/gcc/testsuite/rust/compile/derive_macro7.rs b/gcc/testsuite/rust/compile/derive_macro7.rs
new file mode 100644
index 000000000000..108e3cf90406
--- /dev/null
+++ b/gcc/testsuite/rust/compile/derive_macro7.rs
@@ -0,0 +1,8 @@
+#![feature(rustc_attrs)]
+
+#[rustc_builtin_macro]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[allow_internal_unstable(core_intrinsics, libstd_sys_internals)]
+pub macro RustcDecodable($item:item) {
+    /* compiler built-in */
+}
\ No newline at end of file