Re: [PATCH][stage1] Remove conditionals around free()

[Eric Gallager <egall@gwmail.gwu.edu>]

On 3/4/23, Janne Blomqvist via Gcc-patches <gcc-patches@gcc.gnu.org> wrote:
> On Wed, Mar 1, 2023 at 11:31 PM Bernhard Reutner-Fischer via Fortran
> <fortran@gcc.gnu.org> wrote:
>>
>> Hi!
>>
>> Mere cosmetics.
>>
>> - if (foo != NULL)
>>     free (foo);
>>
>> With the caveat that coccinelle ruins replacement whitespace or i'm
>> uneducated enough to be unable to _not_ run the diff through
>>  sed -e 's/^+\([[:space:]]*\)free(/+\1free (/'
>> at least. If anybody knows how to improve replacement whitespace,
>> i'd be interrested but didn't look nor ask. ISTM that leading
>> whitespace is somewhat ruined, too, so beware (8 spaces versus tab as
>> far as i have spot-checked).
>>
>> Would touch
>>  gcc/ada/rtinit.c             |    3 +--
>>  intl/bindtextdom.c           |    3 +--
>>  intl/loadmsgcat.c            |    6 ++----
>>  intl/localcharset.c          |    3 +--
>>  libbacktrace/xztest.c        |    9 +++------
>>  libbacktrace/zstdtest.c      |    9 +++------
>>  libbacktrace/ztest.c         |    9 +++------
>>  libgfortran/caf/single.c     |    6 ++----
>>  libgfortran/io/async.c       |    6 ++----
>>  libgfortran/io/format.c      |    3 +--
>>  libgfortran/io/transfer.c    |    6 ++----
>>  libgfortran/io/unix.c        |    3 +--
>>  libgo/runtime/go-setenv.c    |    6 ++----
>>  libgo/runtime/go-unsetenv.c  |    3 +--
>>  libgomp/target.c             |    3 +--
>>  libiberty/concat.c           |    3 +--
>>  zlib/contrib/minizip/unzip.c |    2 +-
>>  zlib/contrib/minizip/zip.c   |    2 +-
>>  zlib/examples/enough.c       |    6 ++----
>>  zlib/examples/gun.c          |    2 +-
>>  zlib/examples/gzjoin.c       |    3 +--
>>  zlib/examples/gzlog.c        |    6 ++----
>>
>> coccinelle script and invocation inline.
>> Would need to be split for the respective maintainers and run through
>> mklog with subject changelog and should of course be compiled and
>> tested before that.
>>
>> Remarks:
>> 1) We should do this in if-conversion (?) on our own.
>>    I suppose. Independently of -fdelete-null-pointer-checks
>> 2) Maybe not silently, but raise language awareness nowadays.
>>    By now it's been a long time since this was first mandated.
>> 3) fallout from looking at something completely different
>> 4) i most likely will not remember to split it apart and send proper
>>    patches, tested patches, in stage 1 to maintainers proper, so if
>>    anyone feels like pursuing this, be my guest. I thought i'd just
>>    mention it.
>>
>> cheers,
>
> Back in 2011 Jim Meyering applied a patch doing this, see
> https://gcc.gnu.org/legacy-ml/gcc-patches/2011-03/msg00403.html , and
> the gcc/README.Portability snippet added then which is still there.
>
> Per analysis done then, it seems SunOS 4 was the last system where
> free() of a NULL pointer didn't behave per the spec.
>
> Also in Jim's patch intl/ and zlib/ directories were not touched as
> those are imported from other upstreams.
>

Speaking of which, this reminded me that I opened bug 80528 to catch
code like this as a compiler warning:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80528

> --
> Janne Blomqvist
>