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h2ph generates incorrect code for '#if defined A || defined B' #8449

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p5pRT opened this issue May 11, 2006 · 3 comments
Closed

h2ph generates incorrect code for '#if defined A || defined B' #8449

p5pRT opened this issue May 11, 2006 · 3 comments

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@p5pRT
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@p5pRT p5pRT commented May 11, 2006

Migrated from rt.perl.org#39130 (status was 'resolved')

Searchable as RT39130$

@p5pRT
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@p5pRT p5pRT commented May 11, 2006

From jvdias@redhat.com

Created by jvdias@redhat.com

For cpp statements like :

  #if defined A || defined B

h2ph would generate the code :

  if(defined (defined(&A) ? &A : 0) || defined (defined(&B) ? &B : 0)) {

which is tautologous, as defined(0) is always true .

This turns out to cause real problems on the Linux ppc64 platform,
where "endian-ness" is selectable in the compiler; every inclusion
of "endian.ph", which includes "bits/endian.ph", generates an error​:

$ perl -e 'require "sys/socket.ph";'
Both BIG_ENDIAN and LITTLE_ENDIAN defined! at
/usr/lib/perl5/5.8.8/ppc-linux-thread-multi/bits/endian.ph line 10.
Compilation failed in require at...

Because h2ph generated this code in ../bits/endian.ph​:
if(defined (defined(&__BIG_ENDIAN__) ? &__BIG_ENDIAN__ : 0) || defined (defined(&_BIG_ENDIAN) ? &_BIG_ENDIAN : 0)) {
  if(defined (defined(&__LITTLE_ENDIAN__) ? &__LITTLE_ENDIAN__ : 0) || defined (defined(&_LITTLE_ENDIAN) ? &_LITTLE_ENDIAN : 0)) {
  die("Both\ BIG_ENDIAN\ and\ LITTLE_ENDIAN\ defined\!");
  }
For the cpp code in /usr/include/bits/endian.h​:
#if defined __BIG_ENDIAN__ || defined _BIG_ENDIAN
# if defined __LITTLE_ENDIAN__ || defined _LITTLE_ENDIAN
# error Both BIG_ENDIAN and LITTLE_ENDIAN defined!
...

The problem does not happen if the 'defined..' conditions are in parentheses -
ie.
  #if defined(A) || defined(B)
produces correct code​:
  if( defined(&A) || defined(&B) )

A trivial fix for this is to simply replace the '​: 0' with '​: undef' in
h2ph.PL line 517, as with this patch​:

Inline Patch
--- perl-5.8.8/utils/h2ph.PL~   2006-01-12 17:55:04.000000000 -0500
+++ perl-5.8.8/utils/h2ph.PL    2006-05-11 13:50:04.000000000 -0400
@@ -514,7 +514,7 @@
                }
            } else {
                if ($inif && $new !~ /defined\s*\($/) {
-                   $new .= '(defined(&' . $id . ') ? &' . $id . ' : 0)';
+                   $new .= '(defined(&' . $id . ') ? &' . $id . ' : undef)';
                } elsif (/^\[/) {
                    $new .= " \$$id";
                } else {


Please consider applying the above patch / fixing this issue in maint .

Thanks & Regards,

Jason Vas Dias <jvdias@​redhat.com>
perl package maintainer
Red Hat, Inc.

Perl Info

Flags:
    category=core
    severity=medium

This perlbug was built using Perl v5.8.8 in the Red Hat build system.
It is being executed now by Perl v5.8.8 - Fri Apr 21 17:40:46 EDT 2006.

Site configuration information for perl v5.8.8:

Configured by Red Hat, Inc. at Fri Apr 21 17:40:46 EDT 2006.

Summary of my perl5 (revision 5 version 8 subversion 8) configuration:
  Platform:
    osname=linux, osvers=2.6.16-1.2136_fc6, archname=i386-linux-thread-multi
    uname='linux jvdias 2.6.16-1.2136_fc6 #1 smp tue apr 18 14:56:23 edt 2006 i686 i686 i386 gnulinux '
    config_args='-des -Doptimize=-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m32 -march=i386 -mtune=generic -fasynchronous-unwind-tables -Dversion=5.8.8 -Dmyhostname=localhost -Dperladmin=root@localhost -Dcc=gcc -Dcf_by=Red Hat, Inc. -Dinstallprefix=/usr -Dprefix=/usr -Darchname=i386-linux -Dvendorprefix=/usr -Dsiteprefix=/usr -Duseshrplib -Dusethreads -Duseithreads -Duselargefiles -Dd_dosuid -Dd_semctl_semun -Di_db -Ui_ndbm -Di_gdbm -Di_shadow -Di_syslog -Dman3ext=3pm -Duseperlio -Dinstallusrbinperl=n -Ubincompat5005 -Uversiononly -Dpager=/usr/bin/less -isr -Dd_gethostent_r_proto -Ud_endhostent_r_proto -Ud_sethostent_r_proto -Ud_endprotoent_r_proto -Ud_setprotoent_r_proto -Ud_endservent_r_proto -Ud_setservent_r_proto -Dinc_version_list=5.8.7 5.8.6 5.8.5 5.8.4 5.8.3 -Dscriptdir=/usr/bin'
    hint=recommended, useposix=true, d_sigaction=define
    usethreads=define use5005threads=undef useithreads=define usemultiplicity=define
    useperlio=define d_sfio=undef uselargefiles=define usesocks=undef
    use64bitint=undef use64bitall=undef uselongdouble=undef
    usemymalloc=n, bincompat5005=undef
  Compiler:
    cc='gcc', ccflags ='-D_REENTRANT -D_GNU_SOURCE -DDEBUGGING -fno-strict-aliasing -pipe -Wdeclaration-after-statement -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -I/usr/include/gdbm',
    optimize='-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m32 -march=i386 -mtune=generic -fasynchronous-unwind-tables',
    cppflags='-D_REENTRANT -D_GNU_SOURCE -DDEBUGGING -fno-strict-aliasing -pipe -Wdeclaration-after-statement -I/usr/local/include -I/usr/include/gdbm'
    ccversion='', gccversion='4.1.0 20060420 (Red Hat 4.1.0-9)', gccosandvers=''
    intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12
    ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8
    alignbytes=4, prototype=define
  Linker and Libraries:
    ld='gcc', ldflags =' -L/usr/local/lib'
    libpth=/usr/local/lib /lib /usr/lib
    libs=-lresolv -lnsl -lgdbm -ldb -ldl -lm -lcrypt -lutil -lpthread -lc
    perllibs=-lresolv -lnsl -ldl -lm -lcrypt -lutil -lpthread -lc
    libc=/lib/libc-2.4.so, so=so, useshrplib=true, libperl=libperl.so
    gnulibc_version='2.4'
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E -Wl,-rpath,/usr/lib/perl5/5.8.8/i386-linux-thread-multi/CORE'
    cccdlflags='-fPIC', lddlflags='-shared -L/usr/local/lib'

Locally applied patches:
    


@INC for perl v5.8.8:
    /usr/lib/perl5/site_perl/5.8.8/i386-linux-thread-multi
    /usr/lib/perl5/site_perl/5.8.7/i386-linux-thread-multi
    /usr/lib/perl5/site_perl/5.8.6/i386-linux-thread-multi
    /usr/lib/perl5/site_perl/5.8.5/i386-linux-thread-multi
    /usr/lib/perl5/site_perl/5.8.4/i386-linux-thread-multi
    /usr/lib/perl5/site_perl/5.8.3/i386-linux-thread-multi
    /usr/lib/perl5/site_perl/5.8.8
    /usr/lib/perl5/site_perl/5.8.7
    /usr/lib/perl5/site_perl/5.8.6
    /usr/lib/perl5/site_perl/5.8.5
    /usr/lib/perl5/site_perl/5.8.4
    /usr/lib/perl5/site_perl/5.8.3
    /usr/lib/perl5/site_perl
    /usr/lib/perl5/vendor_perl/5.8.8/i386-linux-thread-multi
    /usr/lib/perl5/vendor_perl/5.8.7/i386-linux-thread-multi
    /usr/lib/perl5/vendor_perl/5.8.6/i386-linux-thread-multi
    /usr/lib/perl5/vendor_perl/5.8.5/i386-linux-thread-multi
    /usr/lib/perl5/vendor_perl/5.8.4/i386-linux-thread-multi
    /usr/lib/perl5/vendor_perl/5.8.3/i386-linux-thread-multi
    /usr/lib/perl5/vendor_perl/5.8.8
    /usr/lib/perl5/vendor_perl/5.8.7
    /usr/lib/perl5/vendor_perl/5.8.6
    /usr/lib/perl5/vendor_perl/5.8.5
    /usr/lib/perl5/vendor_perl/5.8.4
    /usr/lib/perl5/vendor_perl/5.8.3
    /usr/lib/perl5/vendor_perl
    /usr/lib/perl5/5.8.8/i386-linux-thread-multi
    /usr/lib/perl5/5.8.8
    .


Environment for perl v5.8.8:
    HOME=/home/jvd
    LANG=en_US.UTF-8
    LANGUAGE (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/usr/kerberos/bin:/usr/bin:/bin:/usr/bin:/usr/games:/usr/X11R6/bin:/home/jvd/bin
    PERL_BADLANG (unset)
    SHELL=/bin/bash

@p5pRT
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@p5pRT p5pRT commented May 18, 2006

@rgs - Status changed from 'new' to 'resolved'

@p5pRT p5pRT closed this May 18, 2006
@p5pRT
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@p5pRT p5pRT commented May 18, 2006

From @rgs

Jason Vas Dias (via RT) wrote​:

For cpp statements like :

#if defined A || defined B

h2ph would generate the code :

if(defined (defined(&A) ? &A : 0) || defined (defined(&B) ? &B : 0)) {

which is tautologous, as defined(0) is always true .
...
A trivial fix for this is to simply replace the '​: 0' with '​: undef' in
h2ph.PL line 517, as with this patch​:
--- perl-5.8.8/utils/h2ph.PL~ 2006-01-12 17​:55​:04.000000000 -0500
+++ perl-5.8.8/utils/h2ph.PL 2006-05-11 13​:50​:04.000000000 -0400
@​@​ -514,7 +514,7 @​@​
}
} else {
if ($inif && $new !~ /defined\s*\($/) {
- $new .= '(defined(&' . $id . ') ? &' . $id . ' : 0)';
+ $new .= '(defined(&' . $id . ') ? &' . $id . ' : undef)';

Thanks, applied to bleadperl as change #28225.

Please consider applying the above patch / fixing this issue in maint .

(To Nicholas​:) I concur.

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