From: Dave Mitchell <davem@fdisolutions.com>
Date: Thu, 20 Mar 2003 01:26:19 +0000 (+0000)
Subject: [PATCH] Re: [perl #21542] local $_ [0] = $_ [0] fails.
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=51d9a56bf5df931c436b7ede535c78bc64655187;p=p5sagit%2Fp5-mst-13.2.git

[PATCH] Re: [perl #21542] local $_ [0] = $_ [0] fails.
Date: Thu, 20 Mar 2003 01:26:19 +0000
Message-ID: <20030320012619.C19869@fdgroup.com>

Subject: Re: [PATCH] Re: [perl #21542] local $_ [0] = $_ [0] fails.
From: Dave Mitchell <davem@fdgroup.com>
Date: Mon, 24 Mar 2003 16:06:51 +0000
Message-ID: <20030324160651.D1798@fdgroup.com>

p4raw-id: //depot/perl@19064
---

diff --git a/pp_ctl.c b/pp_ctl.c
index a35d600..ac33adf 100644
--- a/pp_ctl.c
+++ b/pp_ctl.c
@@ -1949,6 +1949,7 @@ PP(pp_return)
     }
     PL_stack_sp = newsp;
 
+    LEAVE;
     /* Stack values are safe: */
     if (popsub2) {
 	POPSUB(cx,sv);	/* release CV and @_ ... */
@@ -1957,7 +1958,6 @@ PP(pp_return)
 	sv = Nullsv;
     PL_curpm = newpm;	/* ... and pop $1 et al */
 
-    LEAVE;
     LEAVESUB(sv);
     if (clear_errsv)
 	sv_setpv(ERRSV,"");
@@ -2033,6 +2033,7 @@ PP(pp_last)
     SP = newsp;
     PUTBACK;
 
+    LEAVE;
     /* Stack values are safe: */
     switch (pop2) {
     case CXt_LOOP:
@@ -2045,7 +2046,6 @@ PP(pp_last)
     }
     PL_curpm = newpm;	/* ... and pop $1 et al */
 
-    LEAVE;
     LEAVESUB(sv);
     return nextop;
 }
diff --git a/pp_hot.c b/pp_hot.c
index 5981a5d..15ba94c 100644
--- a/pp_hot.c
+++ b/pp_hot.c
@@ -2320,10 +2320,10 @@ PP(pp_leavesub)
     }
     PUTBACK;
 
+    LEAVE;
     POPSUB(cx,sv);	/* Stack values are safe: release CV and @_ ... */
     PL_curpm = newpm;	/* ... and pop $1 et al */
 
-    LEAVE;
     LEAVESUB(sv);
     return pop_return();
 }
@@ -2376,9 +2376,9 @@ PP(pp_leavesublv)
 	 * the refcounts so the caller gets a live guy. Cannot set
 	 * TEMP, so sv_2mortal is out of question. */
 	if (!CvLVALUE(cx->blk_sub.cv)) {
+	    LEAVE;
 	    POPSUB(cx,sv);
 	    PL_curpm = newpm;
-	    LEAVE;
 	    LEAVESUB(sv);
 	    DIE(aTHX_ "Can't modify non-lvalue subroutine call");
 	}
@@ -2387,9 +2387,9 @@ PP(pp_leavesublv)
 	    EXTEND_MORTAL(1);
 	    if (MARK == SP) {
 		if (SvFLAGS(TOPs) & (SVs_TEMP | SVs_PADTMP | SVf_READONLY)) {
+		    LEAVE;
 		    POPSUB(cx,sv);
 		    PL_curpm = newpm;
-		    LEAVE;
 		    LEAVESUB(sv);
 		    DIE(aTHX_ "Can't return %s from lvalue subroutine",
 			SvREADONLY(TOPs) ? (TOPs == &PL_sv_undef) ? "undef"
@@ -2402,9 +2402,9 @@ PP(pp_leavesublv)
 		}
 	    }
 	    else {			/* Should not happen? */
+		LEAVE;
 		POPSUB(cx,sv);
 		PL_curpm = newpm;
-		LEAVE;
 		LEAVESUB(sv);
 		DIE(aTHX_ "%s returned from lvalue subroutine in scalar context",
 		    (MARK > SP ? "Empty array" : "Array"));
@@ -2418,9 +2418,9 @@ PP(pp_leavesublv)
 		    && SvFLAGS(*mark) & (SVs_TEMP | SVs_PADTMP | SVf_READONLY)) {
 		    /* Might be flattened array after $#array =  */
 		    PUTBACK;
+		    LEAVE;
 		    POPSUB(cx,sv);
 		    PL_curpm = newpm;
-		    LEAVE;
 		    LEAVESUB(sv);
 		    DIE(aTHX_ "Can't return a %s from lvalue subroutine",
 			SvREADONLY(TOPs) ? "readonly value" : "temporary");
@@ -2472,10 +2472,10 @@ PP(pp_leavesublv)
     }
     PUTBACK;
 
+    LEAVE;
     POPSUB(cx,sv);	/* Stack values are safe: release CV and @_ ... */
     PL_curpm = newpm;	/* ... and pop $1 et al */
 
-    LEAVE;
     LEAVESUB(sv);
     return pop_return();
 }
diff --git a/scope.c b/scope.c
index a5cc4f4..a64ec3e 100644
--- a/scope.c
+++ b/scope.c
@@ -604,6 +604,9 @@ Perl_save_aelem(pTHX_ AV *av, I32 idx, SV **sptr)
     SSPUSHINT(idx);
     SSPUSHPTR(SvREFCNT_inc(*sptr));
     SSPUSHINT(SAVEt_AELEM);
+    /* if it gets reified later, the restore will have the wrong refcnt */
+    if (!AvREAL(av) && AvREIFY(av))
+	SvREFCNT_inc(*sptr);
     save_scalar_at(sptr);
     sv = *sptr;
     /* If we're localizing a tied array element, this new sv
@@ -686,7 +689,7 @@ Perl_leave_scope(pTHX_ I32 base)
 	    value = (SV*)SSPOPPTR;
 	    gv = (GV*)SSPOPPTR;
 	    ptr = &GvSV(gv);
-	    SvREFCNT_dec(gv);
+	    av = (AV*)gv; /* what to refcnt_dec */
 	    goto restore_sv;
 	case SAVEt_GENERIC_PVREF:		/* generic pv */
 	    str = (char*)SSPOPPTR;
@@ -719,6 +722,7 @@ Perl_leave_scope(pTHX_ I32 base)
 	case SAVEt_SVREF:			/* scalar reference */
 	    value = (SV*)SSPOPPTR;
 	    ptr = SSPOPPTR;
+	    av = Nullav; /* what to refcnt_dec */
 	restore_sv:
 	    sv = *(SV**)ptr;
 	    DEBUG_S(PerlIO_printf(Perl_debug_log,
@@ -754,6 +758,8 @@ Perl_leave_scope(pTHX_ I32 base)
 	    SvSETMAGIC(value);
 	    PL_localizing = 0;
 	    SvREFCNT_dec(value);
+	    if (av) /* actually an av, hv or gv */
+		SvREFCNT_dec(av);
 	    break;
 	case SAVEt_AV:				/* array reference */
 	    av = (AV*)SSPOPPTR;
@@ -963,13 +969,14 @@ Perl_leave_scope(pTHX_ I32 base)
 	    value = (SV*)SSPOPPTR;
 	    i = SSPOPINT;
 	    av = (AV*)SSPOPPTR;
+	    if (!AvREAL(av) && AvREIFY(av)) /* undo reify guard */
+		SvREFCNT_dec(value);
 	    ptr = av_fetch(av,i,1);
 	    if (ptr) {
 		sv = *(SV**)ptr;
 		if (sv && sv != &PL_sv_undef) {
 		    if (SvTIED_mg((SV*)av, PERL_MAGIC_tied))
 			(void)SvREFCNT_inc(sv);
-		    SvREFCNT_dec(av);
 		    goto restore_sv;
 		}
 	    }
@@ -987,8 +994,8 @@ Perl_leave_scope(pTHX_ I32 base)
 		    ptr = &HeVAL((HE*)ptr);
 		    if (SvTIED_mg((SV*)hv, PERL_MAGIC_tied))
 			(void)SvREFCNT_inc(*(SV**)ptr);
-		    SvREFCNT_dec(hv);
 		    SvREFCNT_dec(sv);
+		    av = (AV*)hv; /* what to refcnt_dec */
 		    goto restore_sv;
 		}
 	    }
diff --git a/t/op/args.t b/t/op/args.t
index ce2c398..90a7d25 100755
--- a/t/op/args.t
+++ b/t/op/args.t
@@ -1,6 +1,6 @@
 #!./perl
 
-print "1..9\n";
+print "1..11\n";
 
 # test various operations on @_
 
@@ -73,3 +73,16 @@ sub try {
 for (1..5) { try() }
 ++$ord;
 print "ok $ord\n";
+
+# bug #21542 local $_[0] causes reify problems and coredumps
+
+sub local1 { local $_[0] }
+my $foo = 'foo'; local1($foo); local1($foo);
+print "got [$foo], expected [foo]\nnot " if $foo ne 'foo';
+$ord++;
+print "ok $ord\n";
+
+sub local2 { local $_[0]; last L }
+L: { local2 }
+$ord++;
+print "ok $ord\n";