This is a live mirror of the Perl 5 development currently hosted at https://github.com/perl/perl5
back out change #22167 "freeing a CV reference that was currently
[perl5.git] / scope.c
diff --git a/scope.c b/scope.c
index 7c02951..2c2ce36 100644 (file)
--- a/scope.c
+++ b/scope.c
@@ -1,6 +1,7 @@
 /*    scope.c
  *
- *    Copyright (c) 1991-2001, Larry Wall
+ *    Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
+ *    2000, 2001, 2002, 2003, by Larry Wall and others
  *
  *    You may distribute under the terms of either the GNU General Public
  *    License or the Artistic License, as specified in the README file.
@@ -81,14 +82,21 @@ Perl_new_stackinfo(pTHX_ I32 stitems, I32 cxitems)
     si->si_cxix = -1;
     si->si_type = PERLSI_UNDEF;
     New(56, si->si_cxstack, cxitems, PERL_CONTEXT);
+    /* Without any kind of initialising PUSHSUBST()
+     * in pp_subst() will read uninitialised heap. */
+    Poison(si->si_cxstack, cxitems, PERL_CONTEXT);
     return si;
 }
 
 I32
 Perl_cxinc(pTHX)
 {
+    IV old_max = cxstack_max;
     cxstack_max = GROW(cxstack_max);
     Renew(cxstack, cxstack_max + 1, PERL_CONTEXT);     /* XXX should fix CXINC macro */
+    /* Without any kind of initialising deep enough recursion
+     * will end up reading uninitialised PERL_CONTEXTs. */
+    Poison(cxstack + old_max + 1, cxstack_max - old_max, PERL_CONTEXT);
     return cxstack_ix + 1;
 }
 
@@ -147,6 +155,13 @@ Perl_savestack_grow(pTHX)
     Renew(PL_savestack, PL_savestack_max, ANY);
 }
 
+void
+Perl_savestack_grow_cnt(pTHX_ I32 need)
+{
+    PL_savestack_max = PL_savestack_ix + need;
+    Renew(PL_savestack, PL_savestack_max, ANY);
+}
+
 #undef GROW
 
 void
@@ -184,9 +199,9 @@ S_save_scalar_at(pTHX_ SV **sptr)
 
     sv = *sptr = NEWSV(0,0);
     if (SvTYPE(osv) >= SVt_PVMG && SvMAGIC(osv) && SvTYPE(osv) != SVt_PVGV) {
+       MAGIC *mg;
        sv_upgrade(sv, SvTYPE(osv));
        if (SvGMAGICAL(osv)) {
-           MAGIC* mg;
            bool oldtainted = PL_tainted;
            mg_get(osv);                /* note, can croak! */
            if (PL_tainting && PL_tainted &&
@@ -199,6 +214,16 @@ S_save_scalar_at(pTHX_ SV **sptr)
            PL_tainted = oldtainted;
        }
        SvMAGIC(sv) = SvMAGIC(osv);
+       /* if it's a special scalar or if it has no 'set' magic,
+        * propagate the SvREADONLY flag. --rgs 20030922 */
+       for (mg = SvMAGIC(sv); mg; mg = mg->mg_moremagic) {
+           if (SvMAGIC(sv)->mg_type == '\0'
+                   || !SvMAGIC(sv)->mg_virtual->svt_set)
+           {
+               SvFLAGS(sv) |= SvREADONLY(osv);
+               break;
+           }
+       }
        SvFLAGS(sv) |= SvMAGICAL(osv);
        /* XXX SvMAGIC() is *shared* between osv and sv.  This can
         * lead to coredumps when both SVs are destroyed without one
@@ -254,10 +279,34 @@ Perl_save_generic_pvref(pTHX_ char **str)
     SSPUSHINT(SAVEt_GENERIC_PVREF);
 }
 
+/* Like save_generic_pvref(), but uses PerlMemShared_free() rather than Safefree().
+ * Can be used to restore a shared global char* to its prior
+ * contents, freeing new value. */
+void
+Perl_save_shared_pvref(pTHX_ char **str)
+{
+    SSCHECK(3);
+    SSPUSHPTR(str);
+    SSPUSHPTR(*str);
+    SSPUSHINT(SAVEt_SHARED_PVREF);
+}
+
+/* set the SvFLAGS specified by mask to the values in val */
+
+void
+Perl_save_set_svflags(pTHX_ SV* sv, U32 mask, U32 val)
+{
+    SSCHECK(4);
+    SSPUSHPTR(sv);
+    SSPUSHINT(mask);
+    SSPUSHINT(val);
+    SSPUSHINT(SAVEt_SET_SVFLAGS);
+}
+
 void
 Perl_save_gp(pTHX_ GV *gv, I32 empty)
 {
-    SSCHECK(6);
+    SSGROW(6);
     SSPUSHIV((IV)SvLEN(gv));
     SvLEN(gv) = 0; /* forget that anything was allocated here */
     SSPUSHIV((IV)SvCUR(gv));
@@ -372,6 +421,15 @@ Perl_save_long(pTHX_ long int *longp)
 }
 
 void
+Perl_save_bool(pTHX_ bool *boolp)
+{
+    SSCHECK(3);
+    SSPUSHBOOL(*boolp);
+    SSPUSHPTR(boolp);
+    SSPUSHINT(SAVEt_BOOL);
+}
+
+void
 Perl_save_I32(pTHX_ I32 *intp)
 {
     SSCHECK(3);
@@ -441,8 +499,9 @@ void
 Perl_save_padsv(pTHX_ PADOFFSET off)
 {
     SSCHECK(4);
+    ASSERT_CURPAD_ACTIVE("save_padsv");
     SSPUSHPTR(PL_curpad[off]);
-    SSPUSHPTR(PL_curpad);
+    SSPUSHPTR(PL_comppad);
     SSPUSHLONG((long)off);
     SSPUSHINT(SAVEt_PADSV);
 }
@@ -450,16 +509,8 @@ Perl_save_padsv(pTHX_ PADOFFSET off)
 SV **
 Perl_save_threadsv(pTHX_ PADOFFSET i)
 {
-#ifdef USE_5005THREADS
-    SV **svp = &THREADSV(i);   /* XXX Change to save by offset */
-    DEBUG_S(PerlIO_printf(Perl_debug_log, "save_threadsv %"UVuf": %p %p:%s\n",
-                         (UV)i, svp, *svp, SvPEEK(*svp)));
-    save_svref(svp);
-    return svp;
-#else
     Perl_croak(aTHX_ "panic: save_threadsv called in non-threaded perl");
     return 0;
-#endif /* USE_5005THREADS */
 }
 
 void
@@ -523,9 +574,11 @@ Perl_save_freepv(pTHX_ char *pv)
 void
 Perl_save_clearsv(pTHX_ SV **svp)
 {
+    ASSERT_CURPAD_ACTIVE("save_clearsv");
     SSCHECK(2);
     SSPUSHLONG((long)(svp-PL_curpad));
     SSPUSHINT(SAVEt_CLEARSV);
+    SvPADSTALE_off(*svp); /* mark lexical as active */
 }
 
 void
@@ -575,23 +628,42 @@ Perl_save_destructor_x(pTHX_ DESTRUCTORFUNC_t f, void* p)
 void
 Perl_save_aelem(pTHX_ AV *av, I32 idx, SV **sptr)
 {
+    SV *sv;
     SSCHECK(4);
     SSPUSHPTR(SvREFCNT_inc(av));
     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
+     * won't actually be stored in the array - so it won't get
+     * reaped when the localize ends. Ensure it gets reaped by
+     * mortifying it instead. DAPM */
+    if (SvTIED_mg(sv, PERL_MAGIC_tiedelem))
+       sv_2mortal(sv);
 }
 
 void
 Perl_save_helem(pTHX_ HV *hv, SV *key, SV **sptr)
 {
+    SV *sv;
     SSCHECK(4);
     SSPUSHPTR(SvREFCNT_inc(hv));
     SSPUSHPTR(SvREFCNT_inc(key));
     SSPUSHPTR(SvREFCNT_inc(*sptr));
     SSPUSHINT(SAVEt_HELEM);
     save_scalar_at(sptr);
+    sv = *sptr;
+    /* If we're localizing a tied hash element, this new sv
+     * won't actually be stored in the hash - so it won't get
+     * reaped when the localize ends. Ensure it gets reaped by
+     * mortifying it instead. DAPM */
+    if (SvTIED_mg(sv, PERL_MAGIC_tiedelem))
+       sv_2mortal(sv);
 }
 
 void
@@ -647,7 +719,7 @@ 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;
@@ -657,6 +729,18 @@ Perl_leave_scope(pTHX_ I32 base)
                *(char**)ptr = str;
            }
            break;
+       case SAVEt_SHARED_PVREF:                /* shared pv */
+           str = (char*)SSPOPPTR;
+           ptr = SSPOPPTR;
+           if (*(char**)ptr != str) {
+#ifdef NETWARE
+               PerlMem_free(*(char**)ptr);
+#else
+               PerlMemShared_free(*(char**)ptr);
+#endif
+               *(char**)ptr = str;
+           }
+           break;
        case SAVEt_GENERIC_SVREF:               /* generic sv */
            value = (SV*)SSPOPPTR;
            ptr = SSPOPPTR;
@@ -668,6 +752,7 @@ 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,
@@ -703,6 +788,8 @@ 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;
@@ -748,6 +835,10 @@ Perl_leave_scope(pTHX_ I32 base)
            ptr = SSPOPPTR;
            *(long*)ptr = (long)SSPOPLONG;
            break;
+       case SAVEt_BOOL:                        /* bool reference */
+           ptr = SSPOPPTR;
+           *(bool*)ptr = (bool)SSPOPBOOL;
+           break;
        case SAVEt_I32:                         /* I32 reference */
            ptr = SSPOPPTR;
            *(I32*)ptr = (I32)SSPOPINT;
@@ -810,8 +901,7 @@ Perl_leave_scope(pTHX_ I32 base)
            break;
        case SAVEt_FREEOP:
            ptr = SSPOPPTR;
-           if (PL_comppad)
-               PL_curpad = AvARRAY(PL_comppad);
+           ASSERT_CURPAD_LEGAL("SAVEt_FREEOP"); /* XXX DAPM tmp */
            op_free((OP*)ptr);
            break;
        case SAVEt_FREEPV:
@@ -821,6 +911,14 @@ Perl_leave_scope(pTHX_ I32 base)
        case SAVEt_CLEARSV:
            ptr = (void*)&PL_curpad[SSPOPLONG];
            sv = *(SV**)ptr;
+
+           DEBUG_Xv(PerlIO_printf(Perl_debug_log,
+            "Pad 0x%"UVxf"[0x%"UVxf"] clearsv: %ld sv=0x%"UVxf"<%"IVdf"> %s\n",
+               PTR2UV(PL_comppad), PTR2UV(PL_curpad),
+               (long)((SV **)ptr-PL_curpad), PTR2UV(sv), (IV)SvREFCNT(sv),
+               (SvREFCNT(sv) <= 1 && !SvOBJECT(sv)) ? "clear" : "abandon"
+           ));
+
            /* Can clear pad variable in place? */
            if (SvREFCNT(sv) <= 1 && !SvOBJECT(sv)) {
                /*
@@ -857,16 +955,19 @@ Perl_leave_scope(pTHX_ I32 base)
                    (void)SvOOK_off(sv);
                    break;
                }
+               SvPADSTALE_on(sv); /* mark as no longer live */
            }
            else {      /* Someone has a claim on this, so abandon it. */
-               U32 padflags = SvFLAGS(sv) & (SVs_PADBUSY|SVs_PADMY|SVs_PADTMP);
+               U32 padflags = SvFLAGS(sv) & (SVs_PADMY|SVs_PADTMP);
                switch (SvTYPE(sv)) {   /* Console ourselves with a new value */
                case SVt_PVAV:  *(SV**)ptr = (SV*)newAV();      break;
                case SVt_PVHV:  *(SV**)ptr = (SV*)newHV();      break;
                default:        *(SV**)ptr = NEWSV(0,0);        break;
                }
                SvREFCNT_dec(sv);       /* Cast current value to the winds. */
-               SvFLAGS(*(SV**)ptr) |= padflags; /* preserve pad nature */
+               /* preserve pad nature, but also mark as not live
+                * for any closure capturing */
+               SvFLAGS(*(SV**)ptr) |= padflags | SVs_PADSTALE;
            }
            break;
        case SAVEt_DELETE:
@@ -898,13 +999,14 @@ 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;
                }
            }
@@ -922,8 +1024,8 @@ 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;
                }
            }
@@ -935,10 +1037,14 @@ Perl_leave_scope(pTHX_ I32 base)
            PL_op = (OP*)SSPOPPTR;
            break;
        case SAVEt_HINTS:
+           if ((PL_hints & HINT_LOCALIZE_HH) && GvHV(PL_hintgv)) {
+               SvREFCNT_dec((SV*)GvHV(PL_hintgv));
+               GvHV(PL_hintgv) = NULL;
+           }
            *(I32*)&PL_hints = (I32)SSPOPINT;
            break;
        case SAVEt_COMPPAD:
-           PL_comppad = (AV*)SSPOPPTR;
+           PL_comppad = (PAD*)SSPOPPTR;
            if (PL_comppad)
                PL_curpad = AvARRAY(PL_comppad);
            else
@@ -949,7 +1055,16 @@ Perl_leave_scope(pTHX_ I32 base)
                PADOFFSET off = (PADOFFSET)SSPOPLONG;
                ptr = SSPOPPTR;
                if (ptr)
-                   ((SV**)ptr)[off] = (SV*)SSPOPPTR;
+                   AvARRAY((PAD*)ptr)[off] = (SV*)SSPOPPTR;
+           }
+           break;
+       case SAVEt_SET_SVFLAGS:
+           {
+               U32 val  = (U32)SSPOPINT;
+               U32 mask = (U32)SSPOPINT;
+               sv = (SV*)SSPOPPTR;
+               SvFLAGS(sv) &= ~mask;
+               SvFLAGS(sv) |= val;
            }
            break;
        default: