gas/Dwarf5: adjust .debug_line file 0 checking

First of all when a table entry has a NULL filename, the two inner if()s
are better done the other way around: The 2nd doesn't depend on what the
first does. This then renders redundant half of the conditions of the
other if() and clarifies that subsequently only entry 0 is dealt with
(indicating that part of the comment was wrong). Finally for there to be
a usable name in slot 1, files_in_use needs to be larger than 1 and slot
1's (rather than slot 0's) name needs to be non-NULL.

diff --git a/gas/dwarf2dbg.c b/gas/dwarf2dbg.c
index c6778fe996abaf85fa11b615869cc9699fcb91a1..c0a052df7d5f94a9c6d0dbe000a2d754b8b813aa 100644 (file)
--- a/gas/dwarf2dbg.c
+++ b/gas/dwarf2dbg.c
@@ -2271,11 +2271,15 @@ out_dir_and_file_list (segT line_seg, int sizeof_offset)
 
       if (files[i].filename == NULL)
        {
-         /* Prevent a crash later, particularly for file 1.  DWARF5
-            uses slot zero, but that is only set explicitly using a
-            .file 0 directive.  If that isn't used, but file 1 is,
-            then use that as main file name.  */
-         if (DWARF2_LINE_VERSION >= 5 && i == 0 && files_in_use >= 1 && files[0].filename == NULL)
+         if (DWARF2_LINE_VERSION < 5 || i != 0)
+           {
+             as_bad (_("unassigned file number %ld"), (long) i);
+             continue;
+           }
+         /* DWARF5 uses slot zero, but that is only set explicitly using
+            a .file 0 directive.  If that isn't used, but file 1 is, then
+            use that as main file name.  */
+         if (files_in_use > 1 && files[1].filename != NULL)
            {
              files[0].filename = files[1].filename;
              files[0].dir = files[1].dir;
@@ -2284,12 +2288,7 @@ out_dir_and_file_list (segT line_seg, int sizeof_offset)
                  files[0].md5[j] = files[1].md5[j];
            }
          else
-           files[i].filename = "";
-         if (DWARF2_LINE_VERSION < 5 || i != 0)
-           {
-             as_bad (_("unassigned file number %ld"), (long) i);
-             continue;
-           }
+           files[0].filename = "";
        }
 
       fullfilename = DWARF2_FILE_NAME (files[i].filename,