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[perl #98184] [PATCH] Use OPpDEREF for lvalue sub, such that the flags contains the deref type, instead of deriving it from the opchain.

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From:
Gerard Goossen
Date:
August 31, 2011 10:55
Subject:
[perl #98184] [PATCH] Use OPpDEREF for lvalue sub, such that the flags contains the deref type, instead of deriving it from the opchain.
Message ID:
rt-3.6.HEAD-31297-1314813323-1615.98184-75-0@perl.org
# New Ticket Created by  Gerard Goossen 
# Please include the string:  [perl #98184]
# in the subject line of all future correspondence about this issue. 
# <URL: https://rt.perl.org:443/rt3/Ticket/Display.html?id=98184 >



This is a bug report for perl from gerard@ggoossen.net,
generated with the help of perlbug 1.39 running under perl 5.15.2.

>From 57e586dab7e727ea61a1f264e0c5cc665007bcdc Mon Sep 17 00:00:00 2001
From: Gerard Goossen <gerard@ggoossen.net>
Date: Wed, 31 Aug 2011 15:55:26 +0200
Subject: [PATCH] Use OPpDEREF for lvalue sub, such that the flags contains
 the deref type, instead of deriving it from the opchain.

Also contains a test were using the opchain to determine the deref
type fails.
---
 cop.h           |    2 +-
 op.c            |    4 +++-
 op.h            |    2 +-
 pp_ctl.c        |   15 +++------------
 t/op/sub_lval.t |    5 ++++-
 5 files changed, 12 insertions(+), 16 deletions(-)

diff --git a/cop.h b/cop.h
index 6512451..8cd8a8a 100644
--- a/cop.h
+++ b/cop.h
@@ -643,7 +643,7 @@ struct block_format {
 	           ? 0 : Perl_was_lvalue_sub(aTHX);			\
 	PUSHSUB_BASE(cx)						\
 	cx->blk_u16 = PL_op->op_private &				\
-	                  (phlags|OPpENTERSUB_DEREF);			\
+	                  (phlags|OPpDEREF);				\
     }
 
 /* variant for use by OP_DBSTATE, where op_private holds hint bits */
diff --git a/op.c b/op.c
index 2b31f09..1d2b437 100644
--- a/op.c
+++ b/op.c
@@ -2177,7 +2177,9 @@ Perl_doref(pTHX_ OP *o, I32 type, bool set_op_ref)
 	    o->op_private &= ~1;
 	}
 	else if (type == OP_RV2SV || type == OP_RV2AV || type == OP_RV2HV){
-	    o->op_private |= OPpENTERSUB_DEREF;
+	    o->op_private |= (type == OP_RV2AV ? OPpDEREF_AV
+			      : type == OP_RV2HV ? OPpDEREF_HV
+			      : OPpDEREF_SV);
 	    o->op_flags |= OPf_MOD;
 	}
 
diff --git a/op.h b/op.h
index 70b6358..903f7cd 100644
--- a/op.h
+++ b/op.h
@@ -206,7 +206,7 @@ Deprecated.  Use C<GIMME_V> instead.
 #define OPpENTERSUB_DB		16	/* Debug subroutine. */
 #define OPpENTERSUB_HASTARG	4	/* Called from OP tree. */
 #define OPpENTERSUB_INARGS	1	/* Lval used as arg to a sub. */
-#define OPpENTERSUB_DEREF	32	/* Lval call that autovivifies. */
+/* used by OPpDEREF             (32|64) */
 /* used by HINT_STRICT_SUBS     2          */
   /* Mask for OP_ENTERSUB flags, the absence of which must be propagated
      in dynamic context */
diff --git a/pp_ctl.c b/pp_ctl.c
index 67b11e3..0d2aae1 100644
--- a/pp_ctl.c
+++ b/pp_ctl.c
@@ -2365,24 +2365,15 @@ S_return_lvalues(pTHX_ SV **mark, SV **sp, SV **newsp, I32 gimme,
 	    EXTEND(newsp,1);
 	    *++newsp = &PL_sv_undef;
 	}
-	if (CxLVAL(cx) & OPpENTERSUB_DEREF) {
+	if (CxLVAL(cx) & OPpDEREF) {
 	    SvGETMAGIC(TOPs);
 	    if (!SvOK(TOPs)) {
-		U8 deref_type;
-		if (cx->blk_sub.retop->op_type == OP_RV2SV)
-		    deref_type = OPpDEREF_SV;
-		else if (cx->blk_sub.retop->op_type == OP_RV2AV)
-		    deref_type = OPpDEREF_AV;
-		else {
-		    assert(cx->blk_sub.retop->op_type == OP_RV2HV);
-		    deref_type = OPpDEREF_HV;
-		}
-		TOPs = vivify_ref(TOPs, deref_type);
+		TOPs = vivify_ref(TOPs, CxLVAL(cx) & OPpDEREF);
 	    }
 	}
     }
     else if (gimme == G_ARRAY) {
-	assert (!(CxLVAL(cx) & OPpENTERSUB_DEREF));
+	assert (!(CxLVAL(cx) & OPpDEREF));
 	if (ref || !CxLVAL(cx))
 	    while (++MARK <= SP)
 		*++newsp =
diff --git a/t/op/sub_lval.t b/t/op/sub_lval.t
index f34fab9..ce5da8d 100644
--- a/t/op/sub_lval.t
+++ b/t/op/sub_lval.t
@@ -3,7 +3,7 @@ BEGIN {
     @INC = '../lib';
     require './test.pl';
 }
-plan tests=>179;
+plan tests=>181;
 
 sub a : lvalue { my $a = 34; ${\(bless \$a)} }  # Return a temporary
 sub b : lvalue { ${\shift} }
@@ -880,6 +880,9 @@ for my $sub (sub :lvalue {$_}, sub :lvalue {return $_}) {
     undef $_;
     %{&$sub()} = (4,5);
     is join('-',%$_), '4-5', '%{func()} autovivification'.$suffix;
+    undef $_;
+    ${ (), &$sub()} = 4;
+    is $$_, 4, '${ (), func()} autovivification'      .$suffix;
 }
 continue { $suffix = ' (explicit return)' }
 
-- 
1.7.5.4

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

Configured by gerard at Wed Aug 31 16:05:28 CEST 2011.

Summary of my perl5 (revision 5 version 15 subversion 2) configuration:
  Derived from: 01d5c162aa4c4b026e65e57d933dcebbe4c706a9
  Platform:
    osname=linux, osvers=3.0.0-1-686-pae, archname=i686-linux-thread-multi
    uname='linux zeus 3.0.0-1-686-pae #1 smp sun jul 24 14:27:32 utc 2011 i686 gnulinux '
    config_args='-des -Dusethreads -Dnoextensions= -Doptimize=-O3 -g3 -DDEBUGGING -Dusedevel -Dprefix=/home/gerard/perl/inst/blead-codegen'
    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=undef
    usemymalloc=n, bincompat5005=undef
  Compiler:
    cc='cc', ccflags ='-D_REENTRANT -D_GNU_SOURCE -DDEBUGGING -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64',
    optimize='-O3 -g3',
    cppflags='-D_REENTRANT -D_GNU_SOURCE -DDEBUGGING -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include'
    ccversion='', gccversion='4.6.1', 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='cc', ldflags =' -fstack-protector -L/usr/local/lib'
    libpth=/usr/local/lib /lib /usr/lib /usr/lib/i386-linux-gnu /usr/lib64
    libs=-lnsl -ldb -ldl -lm -lcrypt -lutil -lpthread -lc
    perllibs=-lnsl -ldl -lm -lcrypt -lutil -lpthread -lc
    libc=, so=so, useshrplib=false, libperl=libperl.a
    gnulibc_version='2.13'
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E'
    cccdlflags='-fPIC', lddlflags='-shared -O3 -g3 -L/usr/local/lib -fstack-protector'

Locally applied patches:
    

---
@INC for perl 5.15.2:
    lib
    /home/gerard/perl/inst/blead-codegen/lib/site_perl/5.15.2/i686-linux-thread-multi
    /home/gerard/perl/inst/blead-codegen/lib/site_perl/5.15.2
    /home/gerard/perl/inst/blead-codegen/lib/5.15.2/i686-linux-thread-multi
    /home/gerard/perl/inst/blead-codegen/lib/5.15.2
    /home/gerard/perl/inst/blead-codegen/lib/site_perl
    .

---
Environment for perl 5.15.2:
    HOME=/home/gerard
    LANG=en_US.UTF-8
    LANGUAGE (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/home/gerard/bin:/usr/local/bin:/usr/bin:/bin:/usr/games
    PERL_BADLANG (unset)
    SHELL=/bin/bash


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