Re: [PATCH][gdb/symtab] Ignore cold clones

[Tom de Vries <tdevries@suse.de>]

On 6/1/21 7:18 AM, Bernd Edlinger wrote:
> So, I did a gcc lto-bootstrap over night with the current trunk version,
> and got these symbols in cc1:
> 
> $ nm cc1|grep do_rpo_vn
> 0000000000fb9a70 T _Z9do_rpo_vnP8functionP8edge_defP11bitmap_head
> 0000000000fb7a40 t _ZL9do_rpo_vnP8functionP8edge_defP11bitmap_headbb.lto_priv.0
> 0000000000719052 t _ZL9do_rpo_vnP8functionP8edge_defP11bitmap_headbb.lto_priv.0.cold
> 
> does your patch handle these?

It does.

Demangled we have:
...
$ c++filt _ZL9do_rpo_vnP8functionP8edge_defP11bitmap_headbb.lto_priv.0.cold
do_rpo_vn(function*, edge_def*, bitmap_head*, bool, bool) [clone
.lto_priv.0] [clone .cold]
...

I build gdb using gcc-11 and -O2 -flto=auto, and found a similar simbol:
...
$ nm -C gdb.lto | grep " init_syscalls_info"
0000000000878a10 T init_syscalls_info(gdbarch*) [clone .lto_priv.0]
0000000000436d19 t init_syscalls_info(gdbarch*) [clone .lto_priv.0] \
                     [clone .cold]
...

With the patch, I have:
...
$ gdb -q -batch ./gdb.lto -ex "b init_syscalls_info" -ex "info break"
Breakpoint 1 at 0x878a10: file xml-syscall.c, line 338.
Num     Type           Disp Enb Address            What
1       breakpoint     keep y   0x0000000000878a10 in
init_syscalls_info(gdbarch*) at xml-syscall.c:338
...
and without:
...
$ gdb -q -batch ./gdb.lto -ex "b init_syscalls_info" -ex "info break"
Breakpoint 1 at 0x436d19: init_syscalls_info. (2 locations)
Num     Type           Disp Enb Address
1       breakpoint     keep y   <MULTIPLE>
1.1                         y   0x0000000000436d19
1.2                         y   0x0000000000878a10
...

Thanks,
- Tom