[Bug gcov-profile/114820] New: Gcov 11.4.0 .gcda:stamp mismatch with notes file

["gejoed at rediffmail dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114820

            Bug ID: 114820
           Summary: Gcov 11.4.0  .gcda:stamp mismatch with notes file
           Product: gcc
           Version: 11.4.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: gcov-profile
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gejoed at rediffmail dot com
  Target Milestone: ---

Hi team,

In my org project we use gcc/gcov which is customised by another team. However
with version 11.4.0 we did see a '.gcda:stamp mismatch with notes file' while
running gcov tool. The same command goes fine with the previous branch code
which uses gcc 10.3.0. 

Example of the command would be like :
<toolchain-path>/gcov -l src-file.c -o ./src-file-obj-dir-path

src-file.gcda:stamp mismatch with notes file      <<<<<<<<
File 'src-file.c'
Lines executed:0.00% of 36
Creating 'src-file.c.gcov'

File '../../abcd/ef/hijk.h'
Lines executed:0.00% of 2
Creating 'src-file.c##hijk.h.gcov'

File '../include/lmno.h'
Lines executed:0.00% of 2
Creating 'src-file.c##lmno.h.gcov'

Lines executed:0.00% of 40

This is seen for several files in the new branch of code where gcc v11.4.0 is
used and not seen with older branch where the gcc version is 10.3.0.

We generate the gcov based image (compiled with --coverage in CFLAGS) , load
the image on the device, do testing, collect gcda files from device and put it
back in the same obj-dir location and run the gcov tool to get the gcov files
(ie. :src-file.c.gcov).

I checked the gcov-dump of the respective gcda and gcno file and saw different
stamp values.
$gcov-dump ./obj-dir-path/src-file.gcda
./obj-dir-path/src-file.gcda:data:magic `gcda':version `B14*'
./obj-dir-path/src-file.gcda:stamp 2912455990
:
<the rest truncated>

$ gcov-dump ./obj-dir-path/src-file.gcno
./obj-dir-path/src-file.gcno:note:magic `gcno':version `B14*'
./obj-dir-path/src-file.gcno:stamp 2912494680
:
<the rest truncated>

-------------------------------
For same file gcno & gcda files in the older branch (where it is gcc10.3.0) the
gcov-dump gives same value :
$gcov-dump src-file.gcda
src-file.gcda:data:magic `gcda':version `B03*'
src-file.gcda:stamp 3176078538
<.....>

$gcov-dump src-file.gcno
src-file.gcno:note:magic `gcno':version `B03*'
src-file.gcno:stamp 3176078538

--------------------------------

I checked if any recompilation of the src file happens (from the build logs)
and I couldn't see any difference between the logs of branches using v11.4.0
and v10.3.0. Do we need to check anything more on why gcda stamp value in the
newer branch(using gcc v11.4.0) is getting different from the gcno value ?
Was there any specific enhancement with 11.x version which would be causing the
issue or is there any further check to be done during the compilation with
--coverage or during the gcov tool run ?

Thank you team for your support always !