[PATCH 2/3] sim: callback: add printf attributes

[Mike Frysinger <vapier@gentoo.org>]

This helps these funcs get printf format checking coverage.

The sim-io.c hack as a result is a bit unfortunate, but the compiler
throws warnings when printing with empty strings.  In this one case,
we actually want that due to the side-effect of the callback halting
execution for us.
---
 include/sim/callback.h | 12 ++++++++----
 sim/common/sim-io.c    |  3 ++-
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/include/sim/callback.h b/include/sim/callback.h
index be72f4503e1a..06aa2d4be790 100644
--- a/include/sim/callback.h
+++ b/include/sim/callback.h
@@ -113,18 +113,22 @@ struct host_callback_struct
   int (*init)     (host_callback *);
 
   /* depreciated, use vprintf_filtered - Talk to the user on a console.  */
-  void (*printf_filtered) (host_callback *, const char *, ...);
+  void (*printf_filtered) (host_callback *, const char *, ...)
+    ATTRIBUTE_PRINTF_2;
 
   /* Talk to the user on a console.  */
-  void (*vprintf_filtered) (host_callback *, const char *, va_list);
+  void (*vprintf_filtered) (host_callback *, const char *, va_list)
+    ATTRIBUTE_PRINTF (2, 0);
 
   /* Same as vprintf_filtered but to stderr.  */
-  void (*evprintf_filtered) (host_callback *, const char *, va_list);
+  void (*evprintf_filtered) (host_callback *, const char *, va_list)
+    ATTRIBUTE_PRINTF (2, 0);
 
   /* Print an error message and "exit".
      In the case of gdb "exiting" means doing a longjmp back to the main
      command loop.  */
-  void (*error) (host_callback *, const char *, ...) ATTRIBUTE_NORETURN;
+  void (*error) (host_callback *, const char *, ...)
+    ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF_2;
 
   int last_errno;		/* host format */
 
diff --git a/sim/common/sim-io.c b/sim/common/sim-io.c
index e09a4af7ba2e..0d14e0dfc452 100644
--- a/sim/common/sim-io.c
+++ b/sim/common/sim-io.c
@@ -309,7 +309,8 @@ sim_io_error (SIM_DESC sd,
     va_start (ap, fmt);
     STATE_CALLBACK (sd)->evprintf_filtered (STATE_CALLBACK (sd), fmt, ap);
     va_end (ap);
-    STATE_CALLBACK (sd)->error (STATE_CALLBACK (sd), "");
+    /* Printing a space here avoids empty printf compiler warnings.  */
+    STATE_CALLBACK (sd)->error (STATE_CALLBACK (sd), " ");
   }
 }
 
-- 
2.31.1