On Thu, 12 Jul 2018 10:37:33 +0100
Stuart Henderson <[email protected]> wrote:
> On 2018/07/12 16:16, YASUOKA Masahiko wrote:
>> > The next command of GDB does not work properly.
>> > I use OpenBSD 6.3 and /usr/bin/gdb (GDB 6.3).
>>
>> It seems that gdb can't read the dwarf generated by clang properly.
>> I found a better fix at the upstream.
>>
>>
>> https://sourceware.org/git/?p=binutils-gdb.git;a=commitdiff;h=ca5f395d6255337974262b4a6f40da531fcf6204
>>
>> ok?
>
> I believe that is a post-GPLv3 commit..
Indeed...
>> Index: gnu/usr.bin/binutils/gdb/dwarf2read.c
>> ===================================================================
>> RCS file: /var/cvs/openbsd/src/gnu/usr.bin/binutils/gdb/dwarf2read.c,v
>> retrieving revision 1.5
>> diff -u -p -r1.5 dwarf2read.c
>> --- gnu/usr.bin/binutils/gdb/dwarf2read.c 27 Dec 2004 21:05:10 -0000
>> 1.5
>> +++ gnu/usr.bin/binutils/gdb/dwarf2read.c 12 Jul 2018 07:07:57 -0000
>> @@ -6479,13 +6479,13 @@ dwarf_decode_lines (struct line_header *
>> * lh->minimum_instruction_length;
>> line += lh->line_base + (adj_opcode % lh->line_range);
>> lh->file_names[file - 1].included_p = 1;
>> - if (!decode_for_pst_p)
>> + if (!decode_for_pst_p && is_stmt)
>> {
>> /* Append row to matrix using current values. */
>> record_line (current_subfile, line,
>> check_cu_functions (address, cu));
>> }
>> - basic_block = 1;
>> + basic_block = 0;
>> }
>> else switch (op_code)
>> {
>> @@ -6499,7 +6499,7 @@ dwarf_decode_lines (struct line_header *
>> case DW_LNE_end_sequence:
>> end_sequence = 1;
>> lh->file_names[file - 1].included_p = 1;
>> - if (!decode_for_pst_p)
>> + if (!decode_for_pst_p && is_stmt)
>> record_line (current_subfile, 0, address);
>> break;
>> case DW_LNE_set_address:
>>
>> On Thu, 28 Jun 2018 14:14:51 +0900 (JST)
>> Masato Asou <[email protected]> wrote:
>> > Hi tech,
>> >
>> > I have a problem and I have ad hoc patch to solve this problem.
>> > However, this patch is AD HOC. Does anybody have correct solution?
>> >
>> > The next command of GDB does not work properly.
>> > I use OpenBSD 6.3 and /usr/bin/gdb (GDB 6.3).
>> >
>> > When I debuging my program with next command, I expect stop at next
>> > line. However, program returned from current function unusual.
>> >
>> > It seems that this problem will occur if there is a WHILE immediately
>> > after the function call.
>> >
>> > Example as below:
>> >
>> > $ uname -a
>> > OpenBSD asou-obsd63.soum.co.jp 6.3 GENERIC#100 amd64
>> > $ cat main.c
>> > #include <err.h>
>> > #include <locale.h>
>> > #include <stdio.h>
>> > #include <unistd.h>
>> >
>> > int
>> > main(int argc, char *argv[])
>> > {
>> > extern void sub(int);
>> > int ch;
>> > int flag_a = 0;
>> >
>> > sub(1);
>> > while ((ch = getopt(argc, argv, "a")) != -1) {
>> > switch (ch) {
>> > case 'a':
>> > flag_a = 1;
>> > break;
>> > default:
>> > err(1, "Unknown option: %c\n", ch);
>> > break;
>> > }
>> > }
>> >
>> > printf("flag_a = %d\n", flag_a);
>> > return (0);
>> > }
>> >
>> > void
>> > sub(int flag)
>> > {
>> > printf("flag = %d\n", flag);
>> > }
>> > $ cc -g main.c
>> > $ gdb a.out
>> > GNU gdb 6.3
>> > Copyright 2004 Free Software Foundation, Inc.
>> > GDB is free software, covered by the GNU General Public License, and you
>> > are
>> > welcome to change it and/or distribute copies of it under certain
>> > conditions.
>> > Type "show copying" to see the conditions.
>> > There is absolutely no warranty for GDB. Type "show warranty" for details.
>> > This GDB was configured as "amd64-unknown-openbsd6.3"...
>> > (gdb) b main
>> > Breakpoint 1 at 0x56b: file main.c, line 11.
>> > (gdb) run
>> > Starting program: /home/asou/tmp/a.out
>> > Breakpoint 1 at 0x12776150056b: file main.c, line 11.
>> >
>> > Breakpoint 1, main (argc=1, argv=0x7f7ffffc3b08) at main.c:11
>> > 11 int flag_a = 0;
>> > Current language: auto; currently minimal
>> > (gdb) next
>> > 13 sub(1);
>> > (gdb) next
>> > flag = 1
>> > 0x0000127761500579 in main (argc=1, argv=0x7f7ffffc3b08)
>> > from /home/asou/tmp/a.out
>> > (gdb) next
>> > Single stepping until exit from function main,
>> > which has no line number information.
>> > flag_a = 0
>> > 0x0000127761500436 in _start () from /home/asou/tmp/a.out
>> > (gdb) bt
>> > #0 0x0000127761500436 in _start () from /home/asou/tmp/a.out
>> > #1 0x0000000000000000 in ?? ()
>> > (gdb)
>> >
>> > My patch as below:
>> >
>> > $ git diff
>> > diff --git a/gnu/usr.bin/binutils/gdb/dwarf2read.c
>> > b/gnu/usr.bin/binutils/gdb/dwarf2read.c
>> > index 96f9e0f8551..651904d763d 100644
>> > --- a/gnu/usr.bin/binutils/gdb/dwarf2read.c
>> > +++ b/gnu/usr.bin/binutils/gdb/dwarf2read.c
>> > @@ -6479,7 +6479,11 @@ dwarf_decode_lines (struct line_header *lh, char
>> > *comp_dir, bfd *abfd,
>> > * lh->minimum_instruction_length;
>> > line += lh->line_base + (adj_opcode % lh->line_range);
>> > lh->file_names[file - 1].included_p = 1;
>> > +#if 0 /* for debug by asou */
>> > if (!decode_for_pst_p)
>> > +#else /* for debug by asou */
>> > + if (line != 0 && !decode_for_pst_p)
>> > +#endif /* for debug by asou */
>> > {
>> > /* Append row to matrix using current values. */
>> > record_line (current_subfile, line,
>> > --
>> > ASOU Masato
>> >
>>
>
