Build-time warnings using g++ as compiler about devel-nytprof

[jkeenan]

#190 -- which is a cherry-pick of a patch from @rurban from 2 years ago -- appears to clear up most of these warnings. Here is my before/after comparison:

Effect of applying rurban patch 5599d1a in branch gpp-build-time-warnings-20210505

[perlmonger: devel-nytprof] $ ~/bin/perl/report-build-warnings gpp.master.output.txt
File:  gpp.master.output.txt

  Wliteral-suffix                           35
  Wwrite-strings                             3

[perlmonger: devel-nytprof] $ ~/bin/perl/report-build-warnings gpp.branch.output.txt
File:  gpp.branch.output.txt

  Wwrite-strings                             3

[jkeenan]

With one more commit to the gpp-build-time-warnings-20210505 branch (#190), we can reduce the remaining number of g++ build-time warnings from 3 to 2.

 ~/bin/perl/report-build-warnings gpp.branch.output.2nd.txt
File:  gpp.branch.output.2nd.txt

  Wwrite-strings                             2

[jkeenan]

With release of CPAN version 6.10, 2 -Wwrite-strings build-time warnings remain when compiling with g++.

[jkeenan]

With release of CPAN version 6.10, 2 -Wwrite-strings build-time warnings remain when compiling with g++.

$ parse-build-warnings 5c915c93d2.freebsd.g++9.make.output.txt.gz 
File:  5c915c93d2.freebsd.g++9.make.output.txt.gz

[
  {
    char   => 37,
    group  => "Wwrite-strings",
    line   => 226,
    source => "NYTProf.xs",
    text   => "ISO C++ forbids converting a string constant to 'char*'",
  },
  {
    char   => 37,
    group  => "Wwrite-strings",
    line   => 231,
    source => "NYTProf.xs",
    text   => "ISO C++ forbids converting a string constant to 'char*'",
  },
]

[jkeenan]

My local and remote machines have been upgraded. Here is a status update on warnings emitted during make when compiling Devel-NYTProf (master branch) with the default versions of g++.

Ubuntu Linux 22.04 LTS

$ g++ --version | head -n 1
g++ (Ubuntu 11.4.0-1ubuntu1~22.04) 11.4.0

$ report-build-warnings 2a11e63e8d.linux.g++-11.make.output.txt.gz 
File:  2a11e63e8d.linux.g++-11.make.output.txt.gz

  Wregister                                  4
  Wwrite-strings                             2

$ parse-build-warnings 2a11e63e8d.linux.g++-11.make.output.txt.gz 
File:  2a11e63e8d.linux.g++-11.make.output.txt.gz

[
  {
    char   => 37,
    group  => "Wwrite-strings",
    line   => 226,
    source => "NYTProf.xs",
    text   => "ISO C++ forbids converting a string constant to \xE2\x80\x98char*\xE2\x80\x99",
  },
  {
    char   => 37,
    group  => "Wwrite-strings",
    line   => 231,
    source => "NYTProf.xs",
    text   => "ISO C++ forbids converting a string constant to \xE2\x80\x98char*\xE2\x80\x99",
  },
  {
    char   => 28,
    group  => "Wregister",
    line   => 1281,
    source => "NYTProf.xs",
    text   => "ISO C++17 does not allow \xE2\x80\x98register\xE2\x80\x99 storage class specifier",
  },
  {
    char   => 18,
    group  => "Wregister",
    line   => 1407,
    source => "NYTProf.xs",
    text   => "ISO C++17 does not allow \xE2\x80\x98register\xE2\x80\x99 storage class specifier",
  },
  {
    char   => 28,
    group  => "Wregister",
    line   => 1408,
    source => "NYTProf.xs",
    text   => "ISO C++17 does not allow \xE2\x80\x98register\xE2\x80\x99 storage class specifier",
  },
  {
    char   => 28,
    group  => "Wregister",
    line   => 1409,
    source => "NYTProf.xs",
    text   => "ISO C++17 does not allow \xE2\x80\x98register\xE2\x80\x99 storage class specifier",
  },
]

FreeBSD-13

$ g++ --version | head -n 1
g++ (FreeBSD Ports Collection) 12.2.0

$ report-build-warnings 2a11e63e8d.freebsd.threaded.gcc12.make.output.tx
t.gz
File:  2a11e63e8d.freebsd.threaded.gcc12.make.output.txt.gz

  Wregister                                  4
  Wwrite-strings                             2

$ parse-build-warnings 2a11e63e8d.freebsd.threaded.gcc12.make.output.txt.gz 
File:  2a11e63e8d.freebsd.threaded.gcc12.make.output.txt.gz

[
  {
    char   => 37,
    group  => "Wwrite-strings",
    line   => 226,
    source => "NYTProf.xs",
    text   => "ISO C++ forbids converting a string constant to 'char*'",
  },
  {
    char   => 37,
    group  => "Wwrite-strings",
    line   => 231,
    source => "NYTProf.xs",
    text   => "ISO C++ forbids converting a string constant to 'char*'",
  },
  {
    char   => 28,
    group  => "Wregister",
    line   => 1281,
    source => "NYTProf.xs",
    text   => "ISO C++17 does not allow 'register' storage class specifier",
  },
  {
    char   => 18,
    group  => "Wregister",
    line   => 1407,
    source => "NYTProf.xs",
    text   => "ISO C++17 does not allow 'register' storage class specifier",
  },
  {
    char   => 28,
    group  => "Wregister",
    line   => 1408,
    source => "NYTProf.xs",
    text   => "ISO C++17 does not allow 'register' storage class specifier",
  },
  {
    char   => 28,
    group  => "Wregister",
    line   => 1409,
    source => "NYTProf.xs",
    text   => "ISO C++17 does not allow 'register' storage class specifier",
  },
]

So on both platforms g++ is now emitting -Wregister warnings related to C++17. Context (from the FreeBSD run):

NYTProf.xs: In function ‘int dopopcx_at(PerlInterpreter*, PERL_CONTEXT*, I32, UV)’:
NYTProf.xs:1281:28: warning: ISO C++17 does not allow ‘register’ storage class specifier [-Wregister]
 1281 |     register PERL_CONTEXT *cx;
      |                            ^~
NYTProf.xs: In function ‘PERL_CONTEXT* visit_contexts(PerlInterpreter*, UV, int (*)(PerlInterpreter*, PERL_CONTEXT*, UV*))’:
NYTProf.xs:1407:18: warning: ISO C++17 does not allow ‘register’ storage class specifier [-Wregister]
 1407 |     register I32 cxix = cxstack_ix;
      |                  ^~~~
NYTProf.xs:1408:28: warning: ISO C++17 does not allow ‘register’ storage class specifier [-Wregister]
 1408 |     register PERL_CONTEXT *cx = NULL;
      |                            ^~
NYTProf.xs:1409:28: warning: ISO C++17 does not allow ‘register’ storage class specifier [-Wregister]
 1409 |     register PERL_CONTEXT *ccstack = cxstack;
      |                            ^~~~~~~

I don't follow C++ development. Is there anyone who could shed some light on this?

[jkeenan]

The 4 -Wregister warnings should be gone as of version 6.13 of Devel-NYTProf, uploaded just now to CPAN. That should leave the 2 -Wwrite-strings warnings.