"unused parameter" warning when building with g++ #15979

p5pRT · 2017-05-14T19:24:51Z

Migrated from rt.perl.org#131314 (status was 'resolved')

Searchable as RT131314$

p5pRT · 2017-05-14T19:24:51Z

From @jkeenan

Observed today running 'make' on perl 5 blead when compiling with:

g++ --version
g++ (Ubuntu 5.4.0-6ubuntu1~16.04.4) 5.4.0 20160609

$ grep -nC2 'warning:' g++.en_US.utf8.typescript
886-g++ -c -DPERL_CORE -fwrapv -fno-strict-aliasing -pipe
-fstack-protector-strong -I/usr/local/include -D_LARGEFILE_SOURCE
-D_FILE_OFFSET_BITS=64 -ansi -O2 -Wall
-Werror=declaration-after-statement -Wextra -Wwrite-strings perlio.c
887-In file included from perlio.c:50:0:
888:XSUB.h:122:43: warning: unused parameter ‘cv’ [-Wunused-parameter]
889- #define XSPROTO(name) void name(pTHX_ CV* cv)
890- ^
--
898- XS(XS_PerlIO__Layer__NoWarnings)
899- ^
900:XSUB.h:122:43: warning: unused parameter ‘cv’ [-Wunused-parameter]
901- #define XSPROTO(name) void name(pTHX_ CV* cv)
902-

The patch attached silences the warning. Please review (for 5.27.0).

Thank you very much.
Jim Keenan

p5pRT · 2017-05-14T19:24:51Z

From @jkeenan

0001-Avoid-unused-parameter-warning-when-compiling-with-g.patch

From b7911fe4c1f885c2c72d97ed9cc223418934f374 Mon Sep 17 00:00:00 2001
From: James E Keenan <jkeenan@cpan.org>
Date: Sun, 14 May 2017 09:57:21 -0400
Subject: [PATCH] Avoid unused-parameter warning when compiling with g++.

---
 XSUB.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/XSUB.h b/XSUB.h
index e74abae..ec7b58d 100644
--- a/XSUB.h
+++ b/XSUB.h
@@ -119,7 +119,7 @@ is a lexical C<$_> in scope.
  * "STATIC", ie. it exports XSUB symbols. You probably don't want that.
  */
 
-#define XSPROTO(name) void name(pTHX_ CV* cv)
+#define XSPROTO(name) void name(pTHX_ CV* cv __attribute__unused__)
 
 #undef XS
 #undef XS_EXTERNAL
-- 
2.7.4

p5pRT · 2017-05-14T19:24:51Z

From @jkeenan

Summary of my perl5 (revision 5 version 26 subversion 0) configuration:
Commit id: 9e71673
Platform:
osname=linux
osvers=4.4.0-77-generic
archname=x86_64-linux
uname='linux zareason 4.4.0-77-generic #98-ubuntu smp wed apr 26 08:34:02 utc 2017 x86_64 x86_64 x86_64 gnulinux '
config_args='-des -Dusedevel -Dcc=g++'
hint=recommended
useposix=true
d_sigaction=define
useithreads=undef
usemultiplicity=undef
use64bitint=define
use64bitall=define
uselongdouble=undef
usemymalloc=n
default_inc_excludes_dot=define
bincompat5005=undef
Compiler:
cc='g++'
ccflags ='-fwrapv -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64'
optimize='-O2'
cppflags='-fwrapv -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include'
ccversion=''
gccversion='5.4.0 20160609'
gccosandvers=''
intsize=4
longsize=8
ptrsize=8
doublesize=8
byteorder=12345678
doublekind=3
d_longlong=define
longlongsize=8
d_longdbl=define
longdblsize=16
longdblkind=3
ivtype='long'
ivsize=8
nvtype='double'
nvsize=8
Off_t='off_t'
lseeksize=8
alignbytes=8
prototype=define
Linker and Libraries:
ld='g++'
ldflags =' -fstack-protector-strong -L/usr/local/lib'
libpth=/usr/include/c++/5 /usr/include/x86_64-linux-gnu/c++/5 /usr/include/c++/5/backward /usr/local/lib /usr/lib/gcc/x86_64-linux-gnu/5/include-fixed /usr/include/x86_64-linux-gnu /usr/lib /lib/x86_64-linux-gnu /lib/../lib /usr/lib/x86_64-linux-gnu /usr/lib/../lib /lib /lib64 /usr/lib64
libs=-lpthread -lnsl -ldb -ldl -lm -lcrypt -lutil -lc
perllibs=-lpthread -lnsl -ldl -lm -lcrypt -lutil -lc
libc=libc-2.23.so
so=so
useshrplib=false
libperl=libperl.a
gnulibc_version='2.23'
Dynamic Linking:
dlsrc=dl_dlopen.xs
dlext=so
d_dlsymun=undef
ccdlflags='-Wl,-E'
cccdlflags='-fPIC'
lddlflags='-shared -O2 -L/usr/local/lib -fstack-protector-strong'

Characteristics of this binary (from libperl):
Compile-time options:
HAS_TIMES
PERLIO_LAYERS
PERL_COPY_ON_WRITE
PERL_DONT_CREATE_GVSV
PERL_MALLOC_WRAP
PERL_OP_PARENT
PERL_PRESERVE_IVUV
PERL_USE_DEVEL
USE_64_BIT_ALL
USE_64_BIT_INT
USE_LARGE_FILES
USE_LOCALE
USE_LOCALE_COLLATE
USE_LOCALE_CTYPE
USE_LOCALE_NUMERIC
USE_LOCALE_TIME
USE_PERLIO
USE_PERL_ATOF
Built under linux
Compiled at May 14 2017 09:10:27
%ENV:
PERLBREW_BASHRC_VERSION="0.78"
PERLBREW_HOME="/home/jkeenan/.perlbrew"
PERLBREW_MANPATH="/home/jkeenan/perl5/perlbrew/perls/perl-5.24.1/man"
PERLBREW_PATH="/home/jkeenan/perl5/perlbrew/bin:/home/jkeenan/perl5/perlbrew/perls/perl-5.24.1/bin"
PERLBREW_PERL="perl-5.24.1"
PERLBREW_ROOT="/home/jkeenan/perl5/perlbrew"
PERLBREW_VERSION="0.78"
PERL_WORKDIR="/home/jkeenan/gitwork/perl"
@INC:
lib
/usr/local/lib/perl5/site_perl/5.26.0/x86_64-linux
/usr/local/lib/perl5/site_perl/5.26.0
/usr/local/lib/perl5/5.26.0/x86_64-linux
/usr/local/lib/perl5/5.26.0

p5pRT · 2017-05-14T19:28:01Z

From @jkeenan

On Sun, 14 May 2017 19:24:51 GMT, jkeenan@pobox.com wrote:

Observed today running 'make' on perl 5 blead when compiling with:

g++ --version
g++ (Ubuntu 5.4.0-6ubuntu1~16.04.4) 5.4.0 20160609

$ grep -nC2 'warning:' g++.en_US.utf8.typescript
886-g++ -c -DPERL_CORE -fwrapv -fno-strict-aliasing -pipe
-fstack-protector-strong -I/usr/local/include -D_LARGEFILE_SOURCE
-D_FILE_OFFSET_BITS=64 -ansi -O2 -Wall
-Werror=declaration-after-statement -Wextra -Wwrite-strings perlio.c
887-In file included from perlio.c:50:0:
888:XSUB.h:122:43: warning: unused parameter ‘cv’ [-Wunused-parameter]
889- #define XSPROTO(name) void name(pTHX_ CV* cv)
890- ^

Available for smoking in the smoke-me/jkeenan/gplusplus-warning branch.

--
James E Keenan (jkeenan@cpan.org)

p5pRT · 2017-05-14T19:28:02Z

From [Unknown Contact. See original ticket]

On Sun, 14 May 2017 19:24:51 GMT, jkeenan@pobox.com wrote:

Observed today running 'make' on perl 5 blead when compiling with:

g++ --version
g++ (Ubuntu 5.4.0-6ubuntu1~16.04.4) 5.4.0 20160609

$ grep -nC2 'warning:' g++.en_US.utf8.typescript
886-g++ -c -DPERL_CORE -fwrapv -fno-strict-aliasing -pipe
-fstack-protector-strong -I/usr/local/include -D_LARGEFILE_SOURCE
-D_FILE_OFFSET_BITS=64 -ansi -O2 -Wall
-Werror=declaration-after-statement -Wextra -Wwrite-strings perlio.c
887-In file included from perlio.c:50:0:
888:XSUB.h:122:43: warning: unused parameter ‘cv’ [-Wunused-parameter]
889- #define XSPROTO(name) void name(pTHX_ CV* cv)
890- ^

Available for smoking in the smoke-me/jkeenan/gplusplus-warning branch.

--
James E Keenan (jkeenan@cpan.org)

p5pRT · 2017-06-01T13:51:52Z

From @jkeenan

On Sun, 14 May 2017 19:24:51 GMT, jkeenan@pobox.com wrote:

Observed today running 'make' on perl 5 blead when compiling with:

g++ --version
g++ (Ubuntu 5.4.0-6ubuntu1~16.04.4) 5.4.0 20160609

$ grep -nC2 'warning:' g++.en_US.utf8.typescript
886-g++ -c -DPERL_CORE -fwrapv -fno-strict-aliasing -pipe
-fstack-protector-strong -I/usr/local/include -D_LARGEFILE_SOURCE
-D_FILE_OFFSET_BITS=64 -ansi -O2 -Wall
-Werror=declaration-after-statement -Wextra -Wwrite-strings perlio.c
887-In file included from perlio.c:50:0:
888:XSUB.h:122:43: warning: unused parameter ‘cv’ [-Wunused-parameter]
889- #define XSPROTO(name) void name(pTHX_ CV* cv)
890- ^

Patch applied to blead in commit 53dfb2b. Will monitor for 7 days, then close unless problems appear.

Thank you very much.

--
James E Keenan (jkeenan@cpan.org)

p5pRT · 2017-06-01T13:51:52Z

The RT System itself - Status changed from 'new' to 'open'

p5pRT · 2017-06-07T21:57:18Z

From @jkeenan

On Thu, 01 Jun 2017 13:51:52 GMT, jkeenan wrote:

On Sun, 14 May 2017 19:24:51 GMT, jkeenan@pobox.com wrote:

Observed today running 'make' on perl 5 blead when compiling with:

g++ --version
g++ (Ubuntu 5.4.0-6ubuntu1~16.04.4) 5.4.0 20160609

$ grep -nC2 'warning:' g++.en_US.utf8.typescript
886-g++ -c -DPERL_CORE -fwrapv -fno-strict-aliasing -pipe
-fstack-protector-strong -I/usr/local/include -D_LARGEFILE_SOURCE
-D_FILE_OFFSET_BITS=64 -ansi -O2 -Wall
-Werror=declaration-after-statement -Wextra -Wwrite-strings perlio.c
887-In file included from perlio.c:50:0:
888:XSUB.h:122:43: warning: unused parameter ‘cv’ [-Wunused-
parameter]
889- #define XSPROTO(name) void name(pTHX_ CV* cv)
890- ^

Patch applied to blead in commit
53dfb2b. Will monitor for 7 days,
then close unless problems appear.

Thank you very much.

Let's explore one smoke-test failure.

[tux], recently you submitted our very first ever smoke test reports using GCC version 7. I'm glad that as part of that effort you tested building perl with g++ version 7.1.1, as reported here:

http://perl5.test-smoke.org/report/56002

The g++-7.1.1 build failed in all cases where you did not include these config_args:

-Duse64bitall -Duselongdouble

#####
Test failures:
~~ ../t/op/sprintf2.t .......................................... FAILED 1492-1497
[stdio/perlio/locale:en_US.utf8] -Dcc=g++ -Duseithreads
[stdio/perlio/locale:en_US.utf8] -Dcc=g++ DEBUGGING
[stdio/perlio/locale:en_US.utf8] -Dcc=g++
[stdio/perlio/locale:en_US.utf8] -Dcc=g++ -Duseithreads DEBUGGING
#####

Have you had a chance to look at these test failures?

I ask because I need to rule out the possibility that the changes in 53dfb2b were the source of the problem.

Thank you very much.

--
James E Keenan (jkeenan@cpan.org)

p5pRT · 2017-06-08T10:55:43Z

From @Tux

On Wed, 07 Jun 2017 14:57:18 -0700, "James E Keenan via RT"
<perlbug-followup@perl.org> wrote:

On Thu, 01 Jun 2017 13:51:52 GMT, jkeenan wrote:

On Sun, 14 May 2017 19:24:51 GMT, jkeenan@pobox.com wrote:

Observed today running 'make' on perl 5 blead when compiling with:

g++ --version
g++ (Ubuntu 5.4.0-6ubuntu1~16.04.4) 5.4.0 20160609

$ grep -nC2 'warning:' g++.en_US.utf8.typescript
886-g++ -c -DPERL_CORE -fwrapv -fno-strict-aliasing -pipe
-fstack-protector-strong -I/usr/local/include -D_LARGEFILE_SOURCE
-D_FILE_OFFSET_BITS=64 -ansi -O2 -Wall
-Werror=declaration-after-statement -Wextra -Wwrite-strings perlio.c
887-In file included from perlio.c:50:0:
888:XSUB.h:122:43: warning: unused parameter ‘cv’ [-Wunused-
parameter]
889- #define XSPROTO(name) void name(pTHX_ CV* cv)
890- ^

Patch applied to blead in commit
53dfb2b. Will monitor for 7 days,
then close unless problems appear.

Thank you very much.

Let's explore one smoke-test failure.

[tux], recently you submitted our very first ever smoke test reports
using GCC version 7. I'm glad that as part of that effort you tested
building perl with g++ version 7.1.1, as reported here:

http://perl5.test-smoke.org/report/56002

The g++-7.1.1 build failed in all cases where you did not include
these config_args:

-Duse64bitall -Duselongdouble

#####
Test failures:
~~ ../t/op/sprintf2.t ..........................................
FAILED 1492-1497 [stdio/perlio/locale:en_US.utf8] -Dcc=g++
-Duseithreads [stdio/perlio/locale:en_US.utf8] -Dcc=g++ DEBUGGING
[stdio/perlio/locale:en_US.utf8] -Dcc=g++
[stdio/perlio/locale:en_US.utf8] -Dcc=g++ -Duseithreads DEBUGGING
#####

Have you had a chance to look at these test failures?

I think they are related to Jarkko's ongoing work on fpclassify and
subnormal behavior:

perl-git/t $ ./perl -I ../lib harness -v op/sprintf2.t |& grep -v '^ok '
# Failed test 1530 - subnormal 0x1.fffffffffffffp-1022 %a 0x1.fffffffffffffp-1022 got 0x0p+0 at op/sprintf2.t line 811
# got "0x0p+0"
# expected "0x1.fffffffffffffp-1022"
# Failed test 1531 - subnormal 0x0.fffffffffffffp-1022 %a 0x1.ffffffffffffep-1023 got 0x0p+0 at op/sprintf2.t line 811
# got "0x0p+0"
# expected "0x1.ffffffffffffep-1023"
# Failed test 1532 - subnormal 0x0.7ffffffffffffp-1022 %a 0x1.ffffffffffffcp-1024 got 0x0p+0 at op/sprintf2.t line 811
# got "0x0p+0"
# expected "0x1.ffffffffffffcp-1024"
# Failed test 1533 - subnormal 0x0.3ffffffffffffp-1022 %a 0x1.ffffffffffff8p-1025 got 0x0p+0 at op/sprintf2.t line 811
# got "0x0p+0"
# expected "0x1.ffffffffffff8p-1025"
# Failed test 1534 - subnormal 0x0.1ffffffffffffp-1022 %a 0x1.ffffffffffffp-1026 got 0x0p+0 at op/sprintf2.t line 811
# got "0x0p+0"
# expected "0x1.ffffffffffffp-1026"
# Failed test 1535 - subnormal 0x0.0ffffffffffffp-1022 %a 0x1.fffffffffffep-1027 got 0x0p+0 at op/sprintf2.t line 811
# got "0x0p+0"
# expected "0x1.fffffffffffep-1027"
op/sprintf2.t ..
# uvsize = 8
# nvsize = 8
# nv_preserves_uv_bits = 53
# d_quad = define
# uselongdouble = undef
not ok 1530 - subnormal 0x1.fffffffffffffp-1022 %a 0x1.fffffffffffffp-1022 got 0x0p+0
not ok 1531 - subnormal 0x0.fffffffffffffp-1022 %a 0x1.ffffffffffffep-1023 got 0x0p+0
not ok 1532 - subnormal 0x0.7ffffffffffffp-1022 %a 0x1.ffffffffffffcp-1024 got 0x0p+0
not ok 1533 - subnormal 0x0.3ffffffffffffp-1022 %a 0x1.ffffffffffff8p-1025 got 0x0p+0
not ok 1534 - subnormal 0x0.1ffffffffffffp-1022 %a 0x1.ffffffffffffp-1026 got 0x0p+0
not ok 1535 - subnormal 0x0.0ffffffffffffp-1022 %a 0x1.fffffffffffep-1027 got 0x0p+0
1..1674
Failed 6/1674 subtests
(less 30 skipped subtests: 1638 okay)

Test Summary Report

op/sprintf2.t (Wstat: 0 Tests: 1674 Failed: 6)
Failed tests: 1530-1535
Files=1, Tests=1674, 0 wallclock secs ( 0.13 usr 0.00 sys + 0.27 cusr 0.12 csys = 0.52 CPU)
Result: FAIL

I ask because I need to rule out the possibility that the changes in
53dfb2b were the source of the
problem.

Thank you very much.

--
H.Merijn Brand http://tux.nl Perl Monger http://amsterdam.pm.org/
using perl5.00307 .. 5.27 porting perl5 on HP-UX, AIX, and openSUSE
http://mirrors.develooper.com/hpux/ http://www.test-smoke.org/
http://qa.perl.org http://www.goldmark.org/jeff/stupid-disclaimers/

p5pRT · 2017-06-08T12:13:44Z

From @jkeenan

On Thu, 08 Jun 2017 10:55:43 GMT, hmbrand wrote:

On Wed, 07 Jun 2017 14:57:18 -0700, "James E Keenan via RT"
[snip]

Let's explore one smoke-test failure.

[tux], recently you submitted our very first ever smoke test reports
using GCC version 7. I'm glad that as part of that effort you tested
building perl with g++ version 7.1.1, as reported here:

http://perl5.test-smoke.org/report/56002

The g++-7.1.1 build failed in all cases where you did not include
these config_args:

-Duse64bitall -Duselongdouble

I think they are related to Jarkko's ongoing work on fpclassify and
subnormal behavior:

Sounds reasonable. Thanks for your rapid response. Marking ticket Resolved.

--
James E Keenan (jkeenan@cpan.org)

p5pRT · 2017-06-08T12:13:45Z

@jkeenan - Status changed from 'open' to 'resolved'

p5pRT closed this as completed Jun 8, 2017

p5pRT added the Severity Low label Oct 19, 2019

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