[PATCH 3/4] Return std::string from gdb_bfd_errmsg

[Tom Tromey <tom@tromey.com>]

This changes gdb_bfd_errmsg to return a std::string, removing a
cleanup.  This approach may be slightly less efficient than the
previous code, but I don't believe this is very important in this
situation.

gdb/ChangeLog
2018-09-03  Tom Tromey  <tom@tromey.com>

	* utils.h (gdb_bfd_errmsg): Return std::string.
	* exec.c (exec_file_attach): Update.
	* compile/compile-object-load.c (compile_object_load): Update.
	* utils.c (gdb_bfd_errmsg): Return std::string.
---
 gdb/ChangeLog                     |  7 +++++++
 gdb/compile/compile-object-load.c |  3 ++-
 gdb/exec.c                        |  2 +-
 gdb/utils.c                       | 27 +++++++--------------------
 gdb/utils.h                       |  2 +-
 5 files changed, 18 insertions(+), 23 deletions(-)

diff --git a/gdb/compile/compile-object-load.c b/gdb/compile/compile-object-load.c
index 873750b9440..40053d281a1 100644
--- a/gdb/compile/compile-object-load.c
+++ b/gdb/compile/compile-object-load.c
@@ -638,7 +638,8 @@ compile_object_load (const compile_file_names &file_names,
 
   if (!bfd_check_format_matches (abfd.get (), bfd_object, &matching))
     error (_("\"%s\": not in loadable format: %s"),
-          filename.get (), gdb_bfd_errmsg (bfd_get_error (), matching));
+	   filename.get (),
+	   gdb_bfd_errmsg (bfd_get_error (), matching).c_str ());
 
   if ((bfd_get_file_flags (abfd.get ()) & (EXEC_P | DYNAMIC)) != 0)
     error (_("\"%s\": not in object format."), filename.get ());
diff --git a/gdb/exec.c b/gdb/exec.c
index 3023ff7e5aa..6e44b0e821b 100644
--- a/gdb/exec.c
+++ b/gdb/exec.c
@@ -362,7 +362,7 @@ exec_file_attach (const char *filename, int from_tty)
 	  exec_close ();
 	  error (_("\"%s\": not in executable format: %s"),
 		 scratch_pathname,
-		 gdb_bfd_errmsg (bfd_get_error (), matching));
+		 gdb_bfd_errmsg (bfd_get_error (), matching).c_str ());
 	}
 
       if (build_section_table (exec_bfd, &sections, &sections_end))
diff --git a/gdb/utils.c b/gdb/utils.c
index 7a8c80c64ed..d7980fe3a18 100644
--- a/gdb/utils.c
+++ b/gdb/utils.c
@@ -2921,39 +2921,26 @@ compare_positive_ints (const void *ap, const void *bp)
 #define AMBIGUOUS_MESS2	\
   ".\nUse \"set gnutarget format-name\" to specify the format."
 
-const char *
+std::string
 gdb_bfd_errmsg (bfd_error_type error_tag, char **matching)
 {
-  char *ret, *retp;
-  int ret_len;
   char **p;
 
   /* Check if errmsg just need simple return.  */
   if (error_tag != bfd_error_file_ambiguously_recognized || matching == NULL)
     return bfd_errmsg (error_tag);
 
-  ret_len = strlen (bfd_errmsg (error_tag)) + strlen (AMBIGUOUS_MESS1)
-            + strlen (AMBIGUOUS_MESS2);
-  for (p = matching; *p; p++)
-    ret_len += strlen (*p) + 1;
-  ret = (char *) xmalloc (ret_len + 1);
-  retp = ret;
-  make_cleanup (xfree, ret);
-
-  strcpy (retp, bfd_errmsg (error_tag));
-  retp += strlen (retp);
-
-  strcpy (retp, AMBIGUOUS_MESS1);
-  retp += strlen (retp);
+  std::string ret (bfd_errmsg (error_tag));
+  ret += AMBIGUOUS_MESS1;
 
   for (p = matching; *p; p++)
     {
-      sprintf (retp, " %s", *p);
-      retp += strlen (retp);
+      ret += " ";
+      ret += *p;
     }
-  xfree (matching);
+  ret += AMBIGUOUS_MESS2;
 
-  strcpy (retp, AMBIGUOUS_MESS2);
+  xfree (matching);
 
   return ret;
 }
diff --git a/gdb/utils.h b/gdb/utils.h
index 68523994b94..fa9a59087da 100644
--- a/gdb/utils.h
+++ b/gdb/utils.h
@@ -115,7 +115,7 @@ compare_cstrings (const char *str1, const char *str2)
    MATCHING, if non-NULL, is the corresponding argument to
    bfd_check_format_matches, and will be freed.  */
 
-extern const char *gdb_bfd_errmsg (bfd_error_type error_tag, char **matching);
+extern std::string gdb_bfd_errmsg (bfd_error_type error_tag, char **matching);
 
 /* Reset the prompt_for_continue clock.  */
 void reset_prompt_for_continue_wait_time (void);
-- 
2.13.6