[Bug gcov-profile/108658] [GCOV] Function entry is not recorded in a function containing an infinite loop from another thread depending on the optimization level

[sebastian.huber--- via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108658

Sebastian Huber <sebastian.hu...@embedded-brains.de> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|INVALID                     |---
             Status|RESOLVED                    |UNCONFIRMED

--- Comment #4 from Sebastian Huber <sebastian.hu...@embedded-brains.de> ---
What is interesting is that -g changes the behaviour. I guess there is an error
in the mapping of the profiling counter to the associated source code lines.

gcc-12 -O2 --coverage -c main.c -g
rm -f *.gc??
gcc-12 -pthread -fprofile-update=atomic -O2 --coverage -c idle.c -g
gcc-12 -pthread --coverage main.o idle.o
./a.out
gcov-12 idle.c
File 'idle.c'
Lines executed:66.67% of 3
Creating 'idle.c.gcov'

Lines executed:66.67% of 3
cat idle.c.gcov
        -:    0:Source:idle.c
        -:    0:Graph:idle.gcno
        -:    0:Data:idle.gcda
        -:    0:Runs:1
    #####:    1:void *idle(void *ignored)
        -:    2:{
213413784:    3:  while (1) {
        -:    4:    /* Do nothing */
213413784:    5:  }
        -:    6:
        -:    7:  return 0;
        -:    8:}
rm -f *.gc??
gcc-12 -pthread -fprofile-update=atomic -Og --coverage -c idle.c -g
gcc-12 -pthread --coverage main.o idle.o
./a.out
gcov-12 idle.c
File 'idle.c'
Lines executed:66.67% of 3
Creating 'idle.c.gcov'

Lines executed:66.67% of 3
cat idle.c.gcov
        -:    0:Source:idle.c
        -:    0:Graph:idle.gcno
        -:    0:Data:idle.gcda
        -:    0:Runs:1
    #####:    1:void *idle(void *ignored)
        -:    2:{
214569562:    3:  while (1) {
        -:    4:    /* Do nothing */
214569562:    5:  }
        -:    6:
        -:    7:  return 0;
        -:    8:}
rm -f *.gc??
gcc-12 -pthread -fprofile-update=atomic -O0 --coverage -c idle.c -g
gcc-12 -pthread --coverage main.o idle.o
./a.out
gcov-12 idle.c
File 'idle.c'
Lines executed:100.00% of 2
Creating 'idle.c.gcov'

Lines executed:100.00% of 2
cat idle.c.gcov
        -:    0:Source:idle.c
        -:    0:Graph:idle.gcno
        -:    0:Data:idle.gcda
        -:    0:Runs:1
214896204:    1:void *idle(void *ignored)
        -:    2:{
214896204:    3:  while (1) {
        -:    4:    /* Do nothing */
        -:    5:  }
        -:    6:
        -:    7:  return 0;
        -:    8:}