bfd/dwarf2.c: allow use of DWARF5 directory entry 0
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Commit Message
I think the test for table->files[file].dir being non-zero is wrong
for DWARF5 where index zero is allowed and is the current directory of
the compilation. Most times this will be covered by the use of
table->comp_dir (from DW_AT_comp_dir) in concat_filename but the point
of putting the current dir in .debug_line was so the section could
stand alone without .debug_info.
Also, there is no need to check for table->dirs non-NULL, the
table->num_dirs test is sufficient.
* dwarf2.c (concat_filename): Correct and simplify tests of
directory index.
@@ -2044,19 +2044,16 @@ concat_filename (struct line_info_table *table, unsigned int file)
char *subdir_name = NULL;
char *name;
size_t len;
-
- if (table->files[file].dir
- /* PR 17512: file: 0317e960. */
- && table->files[file].dir
- <= (table->use_dir_and_file_0 ? table->num_dirs - 1 : table->num_dirs)
- /* PR 17512: file: 7f3d2e4b. */
- && table->dirs != NULL)
- {
- if (table->use_dir_and_file_0)
- subdir_name = table->dirs[table->files[file].dir];
- else
- subdir_name = table->dirs[table->files[file].dir - 1];
- }
+ unsigned int dir = table->files[file].dir;
+
+ if (!table->use_dir_and_file_0)
+ --dir;
+ /* Wrapping from 0 to -1u above gives the intended result with
+ the test below of leaving subdir_name NULL for pre-DWARF5 dir
+ of 0. */
+ /* PR 17512: file: 0317e960, file: 7f3d2e4b. */
+ if (dir < table->num_dirs)
+ subdir_name = table->dirs[dir];
if (!subdir_name || !IS_ABSOLUTE_PATH (subdir_name))
dir_name = table->comp_dir;