[PATCH v2] gdb: CTF support
Weimin Pan
weimin.pan@oracle.com
Wed Sep 25 00:22:00 GMT 2019
On 9/23/2019 8:10 PM, Simon Marchi wrote:
> On 2019-09-23 5:11 p.m., Weimin Pan wrote:
>> Hi Simon,
>>
>> On 9/21/2019 3:21 PM, Simon Marchi wrote:
>>> Hi Weimin,
>>>
>>> I'd like to give this a try and review this, but I hit a wall. I compiled
>>> gcc with this patch series (v5) applied:
>>>
>>> https://gcc.gnu.org/ml/gcc-patches/2019-09/msg00457.html
>>>
>>> I am able to compile a simple .c file with -gt, and the resulting
>>> binary contains a .ctf section. But when loading the file in GDB,
>>> I get this:
>>>
>>> (gdb) file a.out
>>> Reading symbols from a.out...
>>> ctf_bfdopen failed on /home/simark/build/binutils-gdb/gdb/a.out - File data structure corruption detected
>>>
>>> The error occurs in ctf_bufopen, at line 1294:
>>>
>>> 1294 if (hp.cth_lbloff > hp.cth_objtoff
>>> 1295 || hp.cth_objtoff > hp.cth_funcoff
>>> 1296 || hp.cth_funcoff > hp.cth_typeoff
>>> 1297 || hp.cth_funcoff > hp.cth_varoff
>>> 1298 || hp.cth_varoff > hp.cth_typeoff || hp.cth_typeoff > hp.cth_stroff)
>>> 1299 return (ctf_set_open_errno (errp, ECTF_CORRUPT));
>>>
>>> `hp` is:
>>>
>>> $10 = {
>>> cth_preamble = {
>>> ctp_magic = 57330,
>>> ctp_version = 4 '\004',
>>> ctp_flags = 0 '\000'
>>> },
>>> cth_parlabel = 0,
>>> cth_parname = 0,
>>> cth_lbloff = 10,
>>> cth_objtoff = 0,
>>> cth_funcoff = 0,
>>> cth_varoff = 0,
>>> cth_typeoff = 12,
>>> cth_stroff = 12,
>>> cth_strlen = 16
>>> }
>>>
>>> The program I compiled is:
>>>
>>> int main() {
>>> return 2;
>>> }
>>>
>>> compiled with:
>>>
>>> /data/scratch/gcc-install/bin/gcc test.c -gt -O0
>> Looks like you're using the latest gcc patch with current upstream binutils.
>> Unfortunately, these two are not compatible since the latter lacks two newer
>> header fields and the ability to transparently upgrade the ctf header. The
>> same problem can be reproduced with "readelf" from binutils master:
>>
>> % readelf --ctf=".ctf" a.out
>> readelf: Error: CTF open failure: File data structure corruption detected
>>
>> Please try applying the linker patch series that NicK posted on Sep 6 to
>> binutils, under the name of "CTF linking support", as mentioned in the
>> gcc patch sited above:
>>
>> NickA recently posted a changeset to the binutils mailing list that adds
>> initial support for linking CTF sections. Please see
>>
>> https://sourceware.org/ml/binutils/2019-09/msg00045.html
>>
>> ( This current GCCÂ patch set has the ctf.h in sync with the above-mentioned
>> Â Â binutils patch set. )
>>
>> which should fix this problem.
> Oh ok thanks. Do you happen to know if that binutils patchset is available on a
> git branch somewhere? I'd like to avoid applying these 33 patches by hand. If
> you have a combined branch with the binutils and gdb changes together, it would
> be even better :).
Hi Simon,
I have created a combined branch with changes in both binutils and gdb
on our server and tested it a bit. Trying to send it upstream doesn't work:
% git remote -v
origin git://ca-tools4.us.oracle.com/binutils-gdb.git (fetch)
origin git://ca-tools4.us.oracle.com/binutils-gdb.git (push)
upstream       ssh://sourceware.org/git/binutils-gdb.git (fetch)
upstream       ssh://sourceware.org/git/binutils-gdb.git (push)
% git push upstream oracle/ctf:oracle/ctf
Permission denied (publickey).
fatal: Could not read from remote repository.
Please make sure you have the correct access rights
and the repository exists.
%
Weimin
>
> Simon
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