gdb: Make ldirname return a std::string

Eliminates several uses of cleanups.

Tested on x86_64 Fedora 23 with Python 2 and 3.

gdb/ChangeLog
2017-03-27  Pedro Alves  <palves@redhat.com>

	* dwarf2read.c (struct file_and_directory): New.
	(dwarf2_get_dwz_file): Adjust to use std::string.
	(dw2_get_file_names_reader): Adjust to use file_and_directory.
	(find_file_and_directory): Adjust to return a file_and_directory
	object.
	(read_file_scope): Adjust to use file_and_directory.  Remove
	make_cleanup/do_cleanups calls.
	(open_and_init_dwp_file): Adjust to use std::string.  Remove
	make_cleanup/do_cleanups calls.
	* python/python.c (do_start_initialization): Adjust to ldirname
	returning a std::string.
	* utils.c (ldirname): Now returns a std::string.
	* utils.h (ldirname): Change return type to std::string.
	* xml-syscall.c (xml_init_syscalls_info): Adjust to ldirname
	returning a std::string.
	* xml-tdesc.c (file_read_description_xml): Likewise.

1 files changed, 4 insertions, 6 deletions

diff --git a/gdb/utils.c b/gdb/utils.c
index 27021a1..39798cc 100644
--- a/gdb/utils.c
+++ b/gdb/utils.c
@@ -2943,20 +2943,19 @@ dummy_obstack_deallocate (void *object, void *data)
 /* Simple, portable version of dirname that does not modify its
    argument.  */
 
-char *
+std::string
 ldirname (const char *filename)
 {
+  std::string dirname;
   const char *base = lbasename (filename);
-  char *dirname;
 
   while (base > filename && IS_DIR_SEPARATOR (base[-1]))
     --base;
 
   if (base == filename)
-    return NULL;
+    return dirname;
 
-  dirname = (char *) xmalloc (base - filename + 2);
-  memcpy (dirname, filename, base - filename);
+  dirname = std::string (filename, base - filename);
 
   /* On DOS based file systems, convert "d:foo" to "d:.", so that we
      create "d:./bar" later instead of the (different) "d:/bar".  */
@@ -2964,7 +2963,6 @@ ldirname (const char *filename)
       && !IS_DIR_SEPARATOR (filename[0]))
     dirname[base++ - filename] = '.';
 
-  dirname[base - filename] = '\0';
   return dirname;
 }