develooper Front page | perl.perl5.porters | Postings from September 2011

[perl #99426] dead code in ck_sort

From:
Father Chrysostomos
Date:
September 18, 2011 14:25
Subject:
[perl #99426] dead code in ck_sort
Message ID:
rt-3.6.HEAD-31297-1316381129-312.99426-75-0@perl.org
# New Ticket Created by  Father Chrysostomos 
# Please include the string:  [perl #99426]
# in the subject line of all future correspondence about this issue. 
# <URL: https://rt.perl.org:443/rt3/Ticket/Display.html?id=99426 >


This commit added support for sort $coderef @foo:

commit 7a4920e67d1e2d67a4397a908141c6608866ebb0
Author: Graham Barr <gbarr@pobox.com>
Date:   Fri Nov 27 05:16:50 1998 +0000

    integrate change#2246 from mainline, while still allowing
    C<sort $globref @foo>
    
    allow C<sort $coderef @foo>
    
    p4raw-link: @2246 on //depot/perl: c6e96bcb406bc8b8d8610606459ff606ad6883aa
    
    p4raw-id: //depot/maint-5.005/perl@2315
    p4raw-integrated: from //depot/perl@2314 'merge in' t/op/sort.t
    	(@1760..)

But this part of it I don’t understand:

diff --git a/op.c b/op.c
index fcb5f0e..c991051 100644
--- a/op.c
+++ b/op.c
@@ -4768,7 +4768,9 @@ ck_sort(OP *o)
 		kid->op_next = k;
 	    o->op_flags |= OPf_SPECIAL;
 	}
-    }
+	else if (kid->op_type == OP_RV2SV || kid->op_type == OP_PADSV)
+	    null(cLISTOPo->op_first->op_sibling);
+     }
 
     return o;
 }

Nowadays, the op that it is trying to null is already a null, so presumably toke.c or perly.y has changed since then.  So I think this else block can be deleted.

The null I’m referring to is

$ perl -MO=Concise -e 'sort $fo @fo'
8  <@> leave[1 ref] vKP/REFC ->(end)
1     <0> enter ->2
2     <;> nextstate(main 1 -e:1) v:{ ->3
7     <@> sort vKS ->8
3        <0> pushmark s ->4
-        <1> null K/1 ->5                  <-- over here.
-           <1> ex-rv2sv sK/1 ->-
4              <#> gvsv[*fo] s ->5
6        <1> rv2av[t3] lK/1 ->7
5           <#> gv[*fo] s ->6
-e syntax OK

---
Flags:
    category=core
    severity=low
---
Site configuration information for perl 5.15.2:

Configured by sprout at Wed Sep 14 14:21:56 PDT 2011.

Summary of my perl5 (revision 5 version 15 subversion 2) configuration:
  Snapshot of: 828d619543f6e6d3ccfdad45caa681f9105b651a
  Platform:
    osname=darwin, osvers=10.5.0, archname=darwin-thread-multi-ld-2level
    uname='darwin pint.local 10.5.0 darwin kernel version 10.5.0: fri nov 5 23:20:39 pdt 2010; root:xnu-1504.9.17~1release_i386 i386 '
    config_args='-de -Dusedevel -Ui_db -Duseithreads -Duselongdouble -DDEBUGGING=-g'
    hint=recommended, useposix=true, d_sigaction=define
    useithreads=define, usemultiplicity=define
    useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef
    use64bitint=undef, use64bitall=undef, uselongdouble=define
    usemymalloc=n, bincompat5005=undef
  Compiler:
    cc='cc', ccflags ='-fno-common -DPERL_DARWIN -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include',
    optimize='-O3 -g',
    cppflags='-fno-common -DPERL_DARWIN -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include'
    ccversion='', gccversion='4.2.1 (Apple Inc. build 5664)', gccosandvers=''
    intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=16
    ivtype='long', ivsize=4, nvtype='long double', nvsize=16, Off_t='off_t', lseeksize=8
    alignbytes=8, prototype=define
  Linker and Libraries:
    ld='env MACOSX_DEPLOYMENT_TARGET=10.3 cc', ldflags =' -fstack-protector -L/usr/local/lib'
    libpth=/usr/local/lib /usr/lib
    libs=-ldbm -ldl -lm -lutil -lc
    perllibs=-ldl -lm -lutil -lc
    libc=, so=dylib, useshrplib=false, libperl=libperl.a
    gnulibc_version=''
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=bundle, d_dlsymun=undef, ccdlflags=' '
    cccdlflags=' ', lddlflags=' -bundle -undefined dynamic_lookup -L/usr/local/lib -fstack-protector'

Locally applied patches:
    

---
@INC for perl 5.15.2:
    /usr/local/lib/perl5/site_perl/5.15.2/darwin-thread-multi-ld-2level
    /usr/local/lib/perl5/site_perl/5.15.2
    /usr/local/lib/perl5/5.15.2/darwin-thread-multi-ld-2level
    /usr/local/lib/perl5/5.15.2
    /usr/local/lib/perl5/site_perl
    .

---
Environment for perl 5.15.2:
    DYLD_LIBRARY_PATH (unset)
    HOME=/Users/sprout
    LANG=en_US.UTF-8
    LANGUAGE (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin:/usr/local/bin
    PERL_BADLANG (unset)
    SHELL=/bin/bash




nntp.perl.org: Perl Programming lists via nntp and http.
Comments to Ask Bjørn Hansen at ask@perl.org | Group listing | About