preprocessor: Fix non-fn fn-like macro at EOF [PR97471]

We inject EOF tokens between macro argument lists, but had
confused/stale logic in the non-fn invocation.  Renamed the magic
'eof' token, as it's now only used for macro argument termination.
Always rewind the non-OPEN_PAREN token.

	libcpp/
	* internal.h (struct cpp_reader): Rename 'eof' field to 'endarg'.
	* init.c (cpp_create_reader): Adjust.
	* macro.c (collect_args): Use endarg for separator.  Always rewind
	in the not-fn case.
	gcc/testsuite/
	* c-c++-common/cpp/pr97471.c: New.

1 files changed, 8 insertions, 12 deletions

diff --git a/libcpp/macro.c b/libcpp/macro.c
index 2c7d732..9cb3b10 100644
--- a/libcpp/macro.c
+++ b/libcpp/macro.c
@@ -1241,7 +1241,8 @@ collect_args (cpp_reader *pfile, const cpp_hashnode *node,
 	ntokens--;
 
       arg->count = ntokens;
-      set_arg_token (arg, &pfile->eof, pfile->eof.src_loc,
+      /* Append an EOF to mark end-of-argument.  */
+      set_arg_token (arg, &pfile->endarg, token->src_loc,
 		     ntokens, MACRO_ARG_TOKEN_NORMAL,
 		     CPP_OPTION (pfile, track_macro_expansion));
 
@@ -1328,17 +1329,12 @@ funlike_invocation_p (cpp_reader *pfile, cpp_hashnode *node,
       return collect_args (pfile, node, pragma_buff, num_args);
     }
 
-  /* CPP_EOF can be the end of macro arguments, or the end of the
-     file.  We mustn't back up over the latter.  Ugh.  */
-  if (token->type != CPP_EOF || token == &pfile->eof)
-    {
-      /* Back up.  We may have skipped padding, in which case backing
-	 up more than one token when expanding macros is in general
-	 too difficult.  We re-insert it in its own context.  */
-      _cpp_backup_tokens (pfile, 1);
-      if (padding)
-	_cpp_push_token_context (pfile, NULL, padding, 1);
-    }
+  /* Back up.  We may have skipped padding, in which case backing
+     up more than one token when expanding macros is in general
+     too difficult.  We re-insert it in its own context.  */
+  _cpp_backup_tokens (pfile, 1);
+  if (padding)
+    _cpp_push_token_context (pfile, NULL, padding, 1);
 
   return NULL;
 }