# Gfortran -fanalyzer option

**URL:** <https://fortran-lang.discourse.group/t/gfortran-fanalyzer-option/781>\
**Category:** Uncategorized\
**Created:** [March 5, 2021, 1:10pm UTC](https://fortran-lang.discourse.group/t/gfortran-fanalyzer-option/781 "2021-03-05T13:10:26Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![Beliavsky](https://avatars.discourse-cdn.com/v4/letter/b/ba8739/32.png) [@Beliavsky](https://fortran-lang.discourse.group/u/Beliavsky)\
**Post date:** [March 5, 2021, 1:10pm UTC](https://fortran-lang.discourse.group/t/gfortran-fanalyzer-option/781/1 "2021-03-05T13:10:26Z")

</div>

Gcc has an [-fanalyzer option](https://gcc.gnu.org/onlinedocs/gcc-10.2.0/gcc/Static-Analyzer-Options.html) for static analysis, ([added by a developer at Red Hat in 2020](https://developers.redhat.com/blog/2020/03/26/static-analysis-in-gcc-10/)) as does gfortran. Does anyone use if for Fortran code or for C code? I tried it on one of my Fortran source files (5600 lines), and it slowed the compilation dramatically, from 1.3s without to 54s with the -fanalyzer option. The documentation does say “This analysis is much more expensive than other GCC warnings.” `Gfortran -c -fanalyzer statistics.f90` said

```
statistics.f90:338:0:

  338 | if (size(ix) /= size(xx)) return
      | 
Warning: leak of 'istat.0_92' [CWE-401] [-Wanalyzer-malloc-leak]
  'stat_categories_many_str': events 1-3
    |
    | 344 | function stat_categories_many_str(cstat,ncat,ix,xx) result(yy)
    | | 
    |......
    | 350 | yy = stat_categories_many(istat_str(cstat),ncat,ix,xx)
    | | 
    |
    +--> 'stat_categories_many': events 4-7
           |
           | 330 | function stat_categories_many(istat,ncat,ix,xx) result(yy)
           | | 
           |......
           | 338 | if (size(ix) /= size(xx)) return
           | | 
           |

```

for the subroutine

```
function stat_categories_many(istat,ncat,ix,xx) result(yy)
integer , intent(in) :: istat(:)
integer , intent(in) :: ncat
integer , intent(in) :: ix(:)
real(kind=dp), intent(in) :: xx(:)
real(kind=dp) :: yy(size(istat),ncat)
integer :: i
yy = 0.0_dp
if (size(ix) /= size(xx)) return
do i=1,ncat
   yy(:,i) = stat_vec_int_many(istat,pack(xx,ix==i))
end do
end function stat_categories_many

```

I don’t see anything wrong with the code.

---

<div class="post-metadata">

**Author:** ![Beliavsky](https://avatars.discourse-cdn.com/v4/letter/b/ba8739/32.png) [@Beliavsky](https://fortran-lang.discourse.group/u/Beliavsky)\
**Post date:** [March 5, 2021, 1:36pm UTC](https://fortran-lang.discourse.group/t/gfortran-fanalyzer-option/781/2 "2021-03-05T13:36:35Z")

</div>

For the code

```
implicit none
integer, pointer :: ivec(:)
allocate(ivec(2))
ivec = [3,5]
print*,"ivec=",ivec
! deallocate(ivec)
end

```

the -fanalyzer option does say something useful:

```
c:\fortran\test>gfortran -fanalyzer -Wall -Wextra pointer.f90
pointer.f90:7:0:

    7 | end
      | 
Warning: leak of 'ivec.data' [CWE-401] [-Wanalyzer-malloc-leak]
  'main': events 1-2
    |
    |
    +--> 'MAIN__': events 3-14
           |
           | 1 | implicit none
           | | 
           | 2 | integer, pointer :: ivec(:)
           | 3 | allocate(ivec(2))
           | | 
           | 4 | ivec = [3,5]
           | | 
           | 5 | print*,"ivec=",ivec
           | | 
           | 6 | ! deallocate(ivec)
           | 7 | end
           | | 
           |

```

with the -Wall -Wextra options alone, gfortran does not warn about the pointer not being deallocated. I believe such deallocations are recommended before the end of a program.

---

<div class="post-metadata">

**Author:** ![Arjen](https://avatars.discourse-cdn.com/v4/letter/a/b9bd4f/32.png) [@Arjen](https://fortran-lang.discourse.group/u/Arjen)\
**Post date:** [March 5, 2021, 2:11pm UTC](https://fortran-lang.discourse.group/t/gfortran-fanalyzer-option/781/3 "2021-03-05T14:11:20Z")

</div>

O, I did not know of that option - interesting! Like I wrote in another thread, I am collecting small programs that can demonstrate the capabilities of compilers to perform such analyses. The compile time is a trifle bothersome, but then having to dig up an error deep in the code is bothersome too.