patch for gas/dwarf2dbg.c, core dump and corrupted .debug_line section
Jim Wilson
wilson@cygnus.com
Wed Aug 25 20:43:00 GMT 1999
This fixes 4 problems I noticed while trying to use this code from gcc.
1) The comments in get_filenum do not match the code. The code is correct.
2) get_filenum performs an out-of-bounds array access if filenum is 0, which
makes last == -1.
3) get_filenum does not update ls.last_filename when creating a new filetable
entry.
4) dwarf2_gen_line_info saves seg/subseg info after it has already been
clobbered by a subseg_new call. This causes gas to accidentally emit code
into the .debug_line section.
Wed Aug 25 20:20:33 1999 Jim Wilson <wilson@cygnus.com>
* dwarf2dbg.c (out_end_sequence): Correct comments. Set last to
ls.last_filename if last is less than zero. Set ls.last_filename
when allocating new entry.
(dwarf2_gen_line_info): Save seg and subseg info before subseg_new
call.
Index: dwarf2dbg.c
===================================================================
RCS file: /cvs/cvsfiles/devo/gas/dwarf2dbg.c,v
retrieving revision 1.7
diff -p -r1.7 dwarf2dbg.c
*** dwarf2dbg.c 1999/07/23 22:12:34 1.7
--- dwarf2dbg.c 1999/08/26 03:34:48
*************** out_end_sequence ()
*** 359,365 ****
/* Look up a filenumber either by filename or by filenumber. If both
a filenumber and a filename are specified, lookup by filename takes
precedence. If the filename cannot be found, it is added to the
! filetable the filenumber for the new entry is returned. */
static int
get_filenum (filenum, file)
int filenum;
--- 359,365 ----
/* Look up a filenumber either by filename or by filenumber. If both
a filenumber and a filename are specified, lookup by filename takes
precedence. If the filename cannot be found, it is added to the
! filetable and the filenumber for the new entry is returned. */
static int
get_filenum (filenum, file)
int filenum;
*************** get_filenum (filenum, file)
*** 368,377 ****
int i, last = filenum - 1;
char char0 = file[0];
! if (last >= ls.num_filenames)
last = ls.last_filename;
! /* do a quick check against the previously used filename: */
if (ls.num_filenames > 0 && ls.file[last].name[0] == char0
&& strcmp (ls.file[last].name + 1, file + 1) == 0)
return last + 1;
--- 368,379 ----
int i, last = filenum - 1;
char char0 = file[0];
! /* If filenum is out of range of the filename table, then try using the
! table entry returned from the previous call. */
! if (last >= ls.num_filenames || last < 0)
last = ls.last_filename;
! /* Do a quick check against the specified or previously used filenum. */
if (ls.num_filenames > 0 && ls.file[last].name[0] == char0
&& strcmp (ls.file[last].name + 1, file + 1) == 0)
return last + 1;
*************** get_filenum (filenum, file)
*** 395,400 ****
--- 397,403 ----
}
ls.file[ls.num_filenames].dir = 0;
ls.file[ls.num_filenames].name = file;
+ ls.last_filename = ls.num_filenames;
return ++ls.num_filenames;
}
*************** dwarf2_gen_line_info (addr, l)
*** 425,430 ****
--- 428,438 ----
else
return; /* no filename, no filnum => no play */
+ /* Must save these before the subseg_new call, as that call will change
+ them. */
+ saved_seg = now_seg;
+ saved_subseg = now_subseg;
+
if (!ls.line_seg)
{
#ifdef BFD_ASSEMBLER
*************** dwarf2_gen_line_info (addr, l)
*** 445,452 ****
#endif
}
- saved_seg = now_seg;
- saved_subseg = now_subseg;
subseg_set (ls.line_seg, DL_BODY);
if (ls.text_seg != saved_seg || ls.text_subseg != saved_subseg)
--- 453,458 ----
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