Return unique_xmalloc_ptr from target_read_stralloc

This changes target_read_stralloc to return a unique_xmalloc_ptr, and
then fixes all the callers.  unique_xmalloc_ptr is used, rather than
std::string, because target_read_stralloc gives a special meaning to a
NULL return.

ChangeLog
2017-10-16  Tom Tromey  <tom@tromey.com>

	* xml-syscall.c (xml_init_syscalls_info): Update.
	* xml-support.c (xinclude_start_include): Update.
	(xml_fetch_content_from_file): Return unique_xmalloc_ptr.
	* xml-support.h (xml_fetch_another): Return unique_xmalloc_ptr.
	(xml_fetch_content_from_file): Likewise.
	* osdata.c (get_osdata): Update.
	* target.h (target_read_stralloc, target_get_osdata): Return
	unique_xmalloc_ptr.
	* solib-aix.c (solib_aix_get_library_list): Update.
	* solib-target.c (solib_target_current_sos): Update.
	* solib-svr4.c (svr4_current_sos_via_xfer_libraries): Update.
	* xml-tdesc.c (fetch_available_features_from_target): Update.
	(target_fetch_description_xml): Update.
	(file_read_description_xml): Update.
	* remote.c (remote_get_threads_with_qxfer, remote_memory_map)
	(remote_traceframe_info, btrace_read_config, remote_read_btrace)
	(remote_pid_to_exec_file): Update.
	* target.c (target_read_stralloc): Return unique_xmalloc_ptr.
	(target_get_osdata): Likewise.

1 files changed, 3 insertions, 12 deletions

diff --git a/gdb/solib-target.c b/gdb/solib-target.c
index cf569ec3e6..01171f85dd 100644
--- a/gdb/solib-target.c
+++ b/gdb/solib-target.c
@@ -248,27 +248,18 @@ static struct so_list *
 solib_target_current_sos (void)
 {
   struct so_list *new_solib, *start = NULL, *last = NULL;
-  char *library_document;
-  struct cleanup *old_chain;
   VEC(lm_info_target_p) *library_list;
   lm_info_target *info;
   int ix;
 
   /* Fetch the list of shared libraries.  */
-  library_document = target_read_stralloc (&current_target,
-					   TARGET_OBJECT_LIBRARIES,
-					   NULL);
+  gdb::unique_xmalloc_ptr<char> library_document
+    = target_read_stralloc (&current_target, TARGET_OBJECT_LIBRARIES, NULL);
   if (library_document == NULL)
     return NULL;
 
-  /* solib_target_parse_libraries may throw, so we use a cleanup.  */
-  old_chain = make_cleanup (xfree, library_document);
-
   /* Parse the list.  */
-  library_list = solib_target_parse_libraries (library_document);
-
-  /* library_document string is not needed behind this point.  */
-  do_cleanups (old_chain);
+  library_list = solib_target_parse_libraries (library_document.get ());
 
   if (library_list == NULL)
     return NULL;