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, 11 insertions, 26 deletions

diff --git a/gdb/xml-tdesc.c b/gdb/xml-tdesc.c
index daa713f..5a1f459 100644
--- a/gdb/xml-tdesc.c
+++ b/gdb/xml-tdesc.c
@@ -673,24 +673,16 @@ tdesc_parse_xml (const char *document, xml_fetch_another fetcher,
 const struct target_desc *
 file_read_description_xml (const char *filename)
 {
-  struct target_desc *tdesc;
-  char *tdesc_str;
-  struct cleanup *back_to;
-
-  tdesc_str = xml_fetch_content_from_file (filename, NULL);
+  gdb::unique_xmalloc_ptr<char> tdesc_str
+    = xml_fetch_content_from_file (filename, NULL);
   if (tdesc_str == NULL)
     {
       warning (_("Could not open \"%s\""), filename);
       return NULL;
     }
 
-  back_to = make_cleanup (xfree, tdesc_str);
-
-  tdesc = tdesc_parse_xml (tdesc_str, xml_fetch_content_from_file,
-			   (void *) ldirname (filename).c_str ());
-  do_cleanups (back_to);
-
-  return tdesc;
+  return tdesc_parse_xml (tdesc_str.get (), xml_fetch_content_from_file,
+			  (void *) ldirname (filename).c_str ());
 }
 
 /* Read a string representation of available features from the target,
@@ -700,7 +692,7 @@ file_read_description_xml (const char *filename)
    is "target.xml".  Other calls may be performed for the DTD or
    for <xi:include>.  */
 
-static char *
+static gdb::unique_xmalloc_ptr<char>
 fetch_available_features_from_target (const char *name, void *baton_)
 {
   struct target_ops *ops = (struct target_ops *) baton_;
@@ -719,21 +711,14 @@ fetch_available_features_from_target (const char *name, void *baton_)
 const struct target_desc *
 target_read_description_xml (struct target_ops *ops)
 {
-  struct target_desc *tdesc;
-  char *tdesc_str;
-  struct cleanup *back_to;
-
-  tdesc_str = fetch_available_features_from_target ("target.xml", ops);
+  gdb::unique_xmalloc_ptr<char> tdesc_str
+    = fetch_available_features_from_target ("target.xml", ops);
   if (tdesc_str == NULL)
     return NULL;
 
-  back_to = make_cleanup (xfree, tdesc_str);
-  tdesc = tdesc_parse_xml (tdesc_str,
-			   fetch_available_features_from_target,
-			   ops);
-  do_cleanups (back_to);
-
-  return tdesc;
+  return tdesc_parse_xml (tdesc_str.get (),
+			  fetch_available_features_from_target,
+			  ops);
 }
 
 /* Fetches an XML target description using OPS,  processing
@@ -758,7 +743,7 @@ target_fetch_description_xml (struct target_ops *ops)
   struct target_desc *tdesc;
 
   gdb::unique_xmalloc_ptr<char>
-    tdesc_str (fetch_available_features_from_target ("target.xml", ops));
+    tdesc_str = fetch_available_features_from_target ("target.xml", ops);
   if (tdesc_str == NULL)
     return {};