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Re: [patch, dwarf2] avoid segfault on missing directory table
- From: Joel Brobecker <brobecker at adacore dot com>
- To: Sandra Loosemore <sandra at codesourcery dot com>
- Cc: gdb-patches at sourceware dot org, Yao Qi <qiyaoltc at gmail dot com>
- Date: Fri, 8 May 2015 10:23:10 -0700
- Subject: Re: [patch, dwarf2] avoid segfault on missing directory table
- Authentication-results: sourceware.org; auth=none
- References: <554CEDD3 dot 80407 at codesourcery dot com>
> 2015-05-07 Yao Qi <yao@codesourcery.com>
> Sandra Loosemore <sandra@codesourcery.com>
>
> Avoid segfault on missing directory table.
>
> gdb/
> * dwarf2read.c (setup_type_unit_groups): Do NULL pointer check
> to 'lh->include_dirs' before accessing to it.
> (psymtab_include_file_name): Likewise.
> (dwarf_decode_lines_1): Likewise.
> (dwarf_decode_lines): Likewise.
> (file_file_name): Likewise.
It looks reasonable to me.
I might also have added a complaint somewhere, to help diagnoze
mysterious behavior caused by the lack of the include_dirs table.
But I'm not sure where we would have put that complaint without
causing it to be triggered for each and every reference. It's not
very important, as the situation is unlikely.
OK to push.
> diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
> index 4982922..e2ea7e2 100644
> --- a/gdb/dwarf2read.c
> +++ b/gdb/dwarf2read.c
> @@ -9320,7 +9320,7 @@ setup_type_unit_groups (struct die_info *die, struct dwarf2_cu *cu)
> const char *dir = NULL;
> struct file_entry *fe = &lh->file_names[i];
>
> - if (fe->dir_index)
> + if (fe->dir_index && lh->include_dirs != NULL)
> dir = lh->include_dirs[fe->dir_index - 1];
> dwarf2_start_subfile (fe->name, dir);
>
> @@ -17396,7 +17396,7 @@ psymtab_include_file_name (const struct line_header *lh, int file_index,
> char *copied_name = NULL;
> int file_is_pst;
>
> - if (fe.dir_index)
> + if (fe.dir_index && lh->include_dirs != NULL)
> dir_name = lh->include_dirs[fe.dir_index - 1];
>
> if (!IS_ABSOLUTE_PATH (include_name)
> @@ -17595,7 +17595,7 @@ dwarf_decode_lines_1 (struct line_header *lh, struct dwarf2_cu *cu,
> struct file_entry *fe = &lh->file_names[file - 1];
> const char *dir = NULL;
>
> - if (fe->dir_index)
> + if (fe->dir_index && lh->include_dirs != NULL)
> dir = lh->include_dirs[fe->dir_index - 1];
>
> dwarf2_start_subfile (fe->name, dir);
> @@ -17815,7 +17815,7 @@ dwarf_decode_lines_1 (struct line_header *lh, struct dwarf2_cu *cu,
> else
> {
> fe = &lh->file_names[file - 1];
> - if (fe->dir_index)
> + if (fe->dir_index && lh->include_dirs != NULL)
> dir = lh->include_dirs[fe->dir_index - 1];
> if (!decode_for_pst_p)
> {
> @@ -17958,7 +17958,7 @@ dwarf_decode_lines (struct line_header *lh, const char *comp_dir,
> struct file_entry *fe;
>
> fe = &lh->file_names[i];
> - if (fe->dir_index)
> + if (fe->dir_index && lh->include_dirs != NULL)
> dir = lh->include_dirs[fe->dir_index - 1];
> dwarf2_start_subfile (fe->name, dir);
>
> @@ -20640,7 +20640,8 @@ file_file_name (int file, struct line_header *lh)
> {
> struct file_entry *fe = &lh->file_names[file - 1];
>
> - if (IS_ABSOLUTE_PATH (fe->name) || fe->dir_index == 0)
> + if (IS_ABSOLUTE_PATH (fe->name) || fe->dir_index == 0
> + || lh->include_dirs == NULL)
> return xstrdup (fe->name);
> return concat (lh->include_dirs[fe->dir_index - 1], SLASH_STRING,
> fe->name, NULL);
--
Joel