Change gdbscm_exception_message_to_string to return a unique_xmalloc_ptr

This changes gdbscm_exception_message_to_string to return a
unique_xmalloc_ptr, allowing for the removal of some cleanups.
unique_xmalloc_ptr was chosen because at the root of the call chains
is a function from Guile that returns a malloc'd string.

gdb/ChangeLog
2018-07-17  Tom Tromey  <tom@tromey.com>

	* guile/scm-param.c (pascm_signal_setshow_error): Update.
	* guile/guile-internal.h (gdbscm_exception_message_to_string):
	Update.
	* guile/scm-cmd.c (cmdscm_function): Update.
	* guile/scm-pretty-print.c
	(ppscm_print_exception_unless_memory_error): Update.
	* guile/scm-exception.c (gdbscm_exception_message_to_string):
	Return unique_xmalloc_ptr.

1 files changed, 4 insertions, 7 deletions

diff --git a/gdb/guile/scm-exception.c b/gdb/guile/scm-exception.c
index e4b81a1..f0bcdcd 100644
--- a/gdb/guile/scm-exception.c
+++ b/gdb/guile/scm-exception.c
@@ -575,16 +575,13 @@ gdbscm_print_gdb_exception (SCM port, SCM exception)
 
 /* Return a string description of <gdb:exception> EXCEPTION.
    If EXCEPTION is a gdb:with-stack exception, unwrap it, a backtrace
-   is never returned as part of the result.
+   is never returned as part of the result.  */
 
-   Space for the result is malloc'd, the caller must free.  */
-
-char *
+gdb::unique_xmalloc_ptr<char>
 gdbscm_exception_message_to_string (SCM exception)
 {
   SCM port = scm_open_output_string ();
   SCM key, args;
-  char *result;
 
   gdb_assert (gdbscm_is_exception (exception));
 
@@ -601,9 +598,9 @@ gdbscm_exception_message_to_string (SCM exception)
     }
 
   gdbscm_print_exception_message (port, SCM_BOOL_F, key, args);
-  result = gdbscm_scm_to_c_string (scm_get_output_string (port));
+  gdb::unique_xmalloc_ptr<char> result
+    (gdbscm_scm_to_c_string (scm_get_output_string (port)));
   scm_close_port (port);
-
   return result;
 }