This is a live mirror of the Perl 5 development currently hosted at https://github.com/perl/perl5
Don't Deparse "${$}abc" as "$$abc"
[perl5.git] / regexec.c
index cf6b548..a19ede9 100644 (file)
--- a/regexec.c
+++ b/regexec.c
@@ -126,13 +126,16 @@ static const char* const non_utf8_target_but_utf8_required
                     (U8*)(off >= 0 ? reginfo->strend : reginfo->strbeg)) \
            : (U8*)(pos + off))
 
-#define HOPBACKc(pos, off) \
-       (char*)(reginfo->is_utf8_target \
-           ? reghopmaybe3((U8*)pos, (SSize_t)0-off, (U8*)(reginfo->strbeg)) \
-           : (pos - off >= reginfo->strbeg)    \
-               ? (U8*)pos - off                \
+/* like HOPMAYBE3 but backwards. lim must be +ve. Returns NULL on overshoot */
+#define HOPBACK3(pos, off, lim) \
+       (reginfo->is_utf8_target                          \
+           ? reghopmaybe3((U8*)pos, (SSize_t)0-off, (U8*)(lim)) \
+           : (pos - off >= lim)                                 \
+               ? (U8*)pos - off                                 \
                : NULL)
 
+#define HOPBACKc(pos, off) ((char*)HOPBACK3(pos, off, reginfo->strbeg))
+
 #define HOP3(pos,off,lim) (reginfo->is_utf8_target  ? reghop3((U8*)(pos), off, (U8*)(lim)) : (U8*)(pos + off))
 #define HOP3c(pos,off,lim) ((char*)HOP3(pos,off,lim))
 
@@ -704,7 +707,7 @@ Perl_re_intuit_start(pTHX_
        goto fail;
     }
 
-    RX_MATCH_UTF8_set(rx,utf8_target);
+    RXp_MATCH_UTF8_set(prog, utf8_target);
     reginfo->is_utf8_target = cBOOL(utf8_target);
     reginfo->info_aux = NULL;
     reginfo->strbeg = strbeg;
@@ -838,7 +841,7 @@ Perl_re_intuit_start(pTHX_
 #ifdef DEBUGGING       /* 7/99: reports of failure (with the older version) */
     if (end_shift < 0)
        Perl_croak(aTHX_ "panic: end_shift: %" IVdf " pattern:\n%s\n ",
-                  (IV)end_shift, RX_PRECOMP(prog));
+                  (IV)end_shift, RX_PRECOMP(rx));
 #endif
 
   restart:
@@ -884,7 +887,9 @@ Perl_re_intuit_start(pTHX_
                 (IV)prog->check_end_shift);
         });
         
-        end_point = HOP3(strend, -end_shift, strbeg);
+        end_point = HOPBACK3(strend, end_shift, rx_origin);
+        if (!end_point)
+            goto fail_finish;
         start_point = HOPMAYBE3(rx_origin, start_shift, end_point);
         if (!start_point)
             goto fail_finish;
@@ -2766,7 +2771,7 @@ S_reg_set_capture_string(pTHX_ REGEXP * const rx,
             }
             else {
                 /* create new COW SV to share string */
-                RX_MATCH_COPY_FREE(rx);
+                RXp_MATCH_COPY_FREE(prog);
                 prog->saved_copy = sv_setsv_cow(prog->saved_copy, sv);
             }
             prog->subbeg = (char *)SvPVX_const(prog->saved_copy);
@@ -2829,7 +2834,7 @@ S_reg_set_capture_string(pTHX_ REGEXP * const rx,
             assert(min >= 0 && min <= max && min <= strend - strbeg);
             sublen = max - min;
 
-            if (RX_MATCH_COPIED(rx)) {
+            if (RXp_MATCH_COPIED(prog)) {
                 if (sublen > prog->sublen)
                     prog->subbeg =
                             (char*)saferealloc(prog->subbeg, sublen+1);
@@ -2840,7 +2845,7 @@ S_reg_set_capture_string(pTHX_ REGEXP * const rx,
             prog->subbeg[sublen] = '\0';
             prog->suboffset = min;
             prog->sublen = sublen;
-            RX_MATCH_COPIED_on(rx);
+            RXp_MATCH_COPIED_on(prog);
         }
         prog->subcoffset = prog->suboffset;
         if (prog->suboffset && utf8_target) {
@@ -2867,7 +2872,7 @@ S_reg_set_capture_string(pTHX_ REGEXP * const rx,
         }
     }
     else {
-        RX_MATCH_COPY_FREE(rx);
+        RXp_MATCH_COPY_FREE(prog);
         prog->subbeg = strbeg;
         prog->suboffset = 0;
         prog->subcoffset = 0;
@@ -3024,7 +3029,7 @@ Perl_regexec_flags(pTHX_ REGEXP * const rx, char *stringarg, char *strend,
             /* match via INTUIT shouldn't have any captures.
              * Let @-, @+, $^N know */
             prog->lastparen = prog->lastcloseparen = 0;
-            RX_MATCH_UTF8_set(rx, utf8_target);
+            RXp_MATCH_UTF8_set(prog, utf8_target);
             prog->offs[0].start = s - strbeg;
             prog->offs[0].end = utf8_target
                 ? (char*)utf8_hop((U8*)s, prog->minlenret) - strbeg
@@ -3051,8 +3056,8 @@ Perl_regexec_flags(pTHX_ REGEXP * const rx, char *stringarg, char *strend,
        Perl_croak(aTHX_ "corrupted regexp program");
     }
 
-    RX_MATCH_TAINTED_off(rx);
-    RX_MATCH_UTF8_set(rx, utf8_target);
+    RXp_MATCH_TAINTED_off(prog);
+    RXp_MATCH_UTF8_set(prog, utf8_target);
 
     reginfo->prog = rx;         /* Yes, sorry that this is confusing.  */
     reginfo->intuit = 0;
@@ -3374,7 +3379,7 @@ Perl_regexec_flags(pTHX_ REGEXP * const rx, char *stringarg, char *strend,
             regprop(prog, prop, c, reginfo, NULL);
            {
                RE_PV_QUOTED_DECL(quoted,utf8_target,PERL_DEBUG_PAD_ZERO(1),
-                   s,strend-s,60);
+                   s,strend-s,PL_dump_re_max_len);
                 Perl_re_printf( aTHX_
                    "Matching stclass %.*s against %s (%d bytes)\n",
                    (int)SvCUR(prop), SvPVX_const(prop),
@@ -3894,10 +3899,10 @@ S_debug_start_match(pTHX_ const REGEXP *prog, const bool utf8_target,
             reginitcolors();    
     {
         RE_PV_QUOTED_DECL(s0, utf8_pat, PERL_DEBUG_PAD_ZERO(0), 
-            RX_PRECOMP_const(prog), RX_PRELEN(prog), 60);   
+            RX_PRECOMP_const(prog), RX_PRELEN(prog), PL_dump_re_max_len);
         
         RE_PV_QUOTED_DECL(s1, utf8_target, PERL_DEBUG_PAD_ZERO(1),
-            start, end - start, 60); 
+            start, end - start, PL_dump_re_max_len);
         
         Perl_re_printf( aTHX_
             "%s%s REx%s %s against %s\n", 
@@ -3953,11 +3958,11 @@ S_dump_exec_pos(pTHX_ const char *locinput,
        const int is_uni = utf8_target ? 1 : 0;
 
        RE_PV_COLOR_DECL(s0,len0,is_uni,PERL_DEBUG_PAD(0),
-           (locinput - pref_len),pref0_len, 60, 4, 5);
+           (locinput - pref_len),pref0_len, PL_dump_re_max_len, 4, 5);
        
        RE_PV_COLOR_DECL(s1,len1,is_uni,PERL_DEBUG_PAD(1),
                    (locinput - pref_len + pref0_len),
-                   pref_len - pref0_len, 60, 2, 3);
+                   pref_len - pref0_len, PL_dump_re_max_len, 2, 3);
        
        RE_PV_COLOR_DECL(s2,len2,is_uni,PERL_DEBUG_PAD(2),
                    locinput, loc_regeol - locinput, 10, 0, 1);
@@ -4340,7 +4345,7 @@ S_isGCB(pTHX_ const GCB_enum before, const GCB_enum after, const U8 * const strb
                 /* Do not break within emoji flag sequences. That is, do not
                  * break between regional indicator (RI) symbols if there is an
                  * odd number of RI characters before the break point.
-                 *  GB12     ^ (RI RI)* RI × RI
+                 *  GB12   sot (RI RI)* RI × RI
                  *  GB13 [^RI] (RI RI)* RI × RI */
 
                 while (backup_one_GCB(strbeg,
@@ -4632,7 +4637,7 @@ S_isLB(pTHX_ LB_enum before,
                  * only if there are an even number of regional indicators
                  * preceding the position of the break.
                  *
-                 *  sot (RI RI)* RI × RI
+                 *    sot (RI RI)* RI × RI
                  *  [^RI] (RI RI)* RI × RI */
 
                 while (backup_one_LB(strbeg,
@@ -5162,7 +5167,7 @@ S_isWB(pTHX_ WB_enum previous,
                  * odd number of RI characters before the potential break
                  * point.
                  *
-                 * WB15     ^ (RI RI)* RI × RI
+                 * WB15   sot (RI RI)* RI × RI
                  * WB16 [^RI] (RI RI)* RI × RI */
 
                 while (backup_one_WB(&previous,
@@ -5370,7 +5375,7 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
     SV *sv_yes_mark = NULL; /* last mark name we have seen 
                                during a successful match */
     U32 lastopen = 0;       /* last open we saw */
-    bool has_cutgroup = RX_HAS_CUTGROUP(rex) ? 1 : 0;   
+    bool has_cutgroup = RXp_HAS_CUTGROUP(rex) ? 1 : 0;
     SV* const oreplsv = GvSVn(PL_replgv);
     /* these three flags are set by various ops to signal information to
      * the very next op. They have a useful lifetime of exactly one loop
@@ -5391,12 +5396,12 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
     U8 gimme = G_SCALAR;
     CV *caller_cv = NULL;      /* who called us */
     CV *last_pushed_cv = NULL; /* most recently called (?{}) CV */
-    CHECKPOINT runops_cp;      /* savestack position before executing EVAL */
     U32 maxopenparen = 0;       /* max '(' index seen so far */
     int to_complement;  /* Invert the result? */
     _char_class_number classnum;
     bool is_utf8_pat = reginfo->is_utf8_pat;
     bool match = FALSE;
+    I32 orig_savestack_ix = PL_savestack_ix;
 
 /* Solaris Studio 12.3 messes up fetching PL_charclass['\n'] */
 #if (defined(__SUNPRO_C) && (__SUNPRO_C == 0x5120) && defined(__x86_64) && defined(USE_64_BIT_ALL))
@@ -5593,6 +5598,7 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
                 if (scan->flags == EXACTL || scan->flags == EXACTFLU8) {
                     _CHECK_AND_WARN_PROBLEMATIC_LOCALE;
                     if (utf8_target
+                        && nextchr >= 0 /* guard against negative EOS value in nextchr */
                         && UTF8_IS_ABOVE_LATIN1(nextchr)
                         && scan->flags == EXACTL)
                     {
@@ -5736,6 +5742,11 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
         {
             U8 *uc;
             if ( ST.jump ) {
+                /* undo any captures done in the tail part of a branch,
+                 * e.g.
+                 *    /(?:X(.)(.)|Y(.)).../
+                 * where the trie just matches X then calls out to do the
+                 * rest of the branch */
                 REGCP_UNWIND(ST.cp);
                 UNWIND_PAREN(ST.lastparen, ST.lastcloseparen);
            }
@@ -6786,7 +6797,7 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
             goto eval_recurse_doit;
             /* NOTREACHED */
 
-        case EVAL:  /*   /(?{A})B/   /(??{A})B/  and /(?(?{A})X|Y)B/   */        
+        case EVAL:  /*   /(?{...})B/   /(??{A})B/  and  /(?(?{...})X|Y)B/   */
             if (cur_eval && cur_eval->locinput==locinput) {
                if ( ++nochange_depth > max_nochange_depth )
                     Perl_croak(aTHX_ "EVAL without pos change exceeded limit in regex");
@@ -6805,7 +6816,7 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
 
                /* save *all* paren positions */
                 regcppush(rex, 0, maxopenparen);
-               REGCP_SET(runops_cp);
+                REGCP_SET(ST.lastcp);
 
                if (!caller_cv)
                    caller_cv = find_runcv(NULL);
@@ -6830,30 +6841,67 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
                    nop = (OP*)rexi->data->data[n];
                }
 
-               /* normally if we're about to execute code from the same
-                * CV that we used previously, we just use the existing
-                * CX stack entry. However, its possible that in the
-                * meantime we may have backtracked, popped from the save
-                * stack, and undone the SAVECOMPPAD(s) associated with
-                * PUSH_MULTICALL; in which case PL_comppad no longer
-                * points to newcv's pad. */
+                /* Some notes about MULTICALL and the context and save stacks.
+                 *
+                 * In something like
+                 *   /...(?{ my $x)}...(?{ my $y)}...(?{ my $z)}.../
+                 * since codeblocks don't introduce a new scope (so that
+                 * local() etc accumulate), at the end of a successful
+                 * match there will be a SAVEt_CLEARSV on the savestack
+                 * for each of $x, $y, $z. If the three code blocks above
+                 * happen to have come from different CVs (e.g. via
+                 * embedded qr//s), then we must ensure that during any
+                 * savestack unwinding, PL_comppad always points to the
+                 * right pad at each moment. We achieve this by
+                 * interleaving SAVEt_COMPPAD's on the savestack whenever
+                 * there is a change of pad.
+                 * In theory whenever we call a code block, we should
+                 * push a CXt_SUB context, then pop it on return from
+                 * that code block. This causes a bit of an issue in that
+                 * normally popping a context also clears the savestack
+                 * back to cx->blk_oldsaveix, but here we specifically
+                 * don't want to clear the save stack on exit from the
+                 * code block.
+                 * Also for efficiency we don't want to keep pushing and
+                 * popping the single SUB context as we backtrack etc.
+                 * So instead, we push a single context the first time
+                 * we need, it, then hang onto it until the end of this
+                 * function. Whenever we encounter a new code block, we
+                 * update the CV etc if that's changed. During the times
+                 * in this function where we're not executing a code
+                 * block, having the SUB context still there is a bit
+                 * naughty - but we hope that no-one notices.
+                 * When the SUB context is initially pushed, we fake up
+                 * cx->blk_oldsaveix to be as if we'd pushed this context
+                 * on first entry to S_regmatch rather than at some random
+                 * point during the regexe execution. That way if we
+                 * croak, popping the context stack will ensure that
+                 * *everything* SAVEd by this function is undone and then
+                 * the context popped, rather than e.g., popping the
+                 * context (and restoring the original PL_comppad) then
+                 * popping more of the savestack and restoring a bad
+                 * PL_comppad.
+                 */
+
+                /* If this is the first EVAL, push a MULTICALL. On
+                 * subsequent calls, if we're executing a different CV, or
+                 * if PL_comppad has got messed up from backtracking
+                 * through SAVECOMPPADs, then refresh the context.
+                 */
                if (newcv != last_pushed_cv || PL_comppad != last_pad)
                {
                     U8 flags = (CXp_SUB_RE |
                                 ((newcv == caller_cv) ? CXp_SUB_RE_FAKE : 0));
+                    SAVECOMPPAD();
                    if (last_pushed_cv) {
-                        /* PUSH/POP_MULTICALL save and restore the
-                         * caller's PL_comppad; if we call multiple subs
-                         * using the same CX block, we have to save and
-                         * unwind the varying PL_comppad's ourselves,
-                         * especially restoring the right PL_comppad on
-                         * backtrack - so save it on the save stack */
-                        SAVECOMPPAD();
                        CHANGE_MULTICALL_FLAGS(newcv, flags);
                    }
                    else {
                        PUSH_MULTICALL_FLAGS(newcv, flags);
                    }
+                    /* see notes above */
+                    CX_CUR()->blk_oldsaveix = orig_savestack_ix;
+
                    last_pushed_cv = newcv;
                }
                else {
@@ -6935,7 +6983,7 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
                if (logical == 0)        /*   (?{})/   */
                    sv_setsv(save_scalar(PL_replgv), ret); /* $^R */
                else if (logical == 1) { /*   /(?(?{...})X|Y)/    */
-                   sw = cBOOL(SvTRUE(ret));
+                   sw = cBOOL(SvTRUE_NN(ret));
                    logical = 0;
                }
                else {                   /*  /(??{})  */
@@ -6970,12 +7018,14 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
                 * in the regexp code uses the pad ! */
                PL_op = oop;
                PL_curcop = ocurcop;
-                regcp_restore(rex, runops_cp, &maxopenparen);
+                regcp_restore(rex, ST.lastcp, &maxopenparen);
                 PL_curpm_under = PL_curpm;
                 PL_curpm = PL_reg_curpm;
 
-               if (logical != 2)
-                   break;
+               if (logical != 2) {
+                    PUSH_STATE_GOTO(EVAL_B, next, locinput);
+                   /* NOTREACHED */
+                }
            }
 
                /* only /(??{})/  from now on */
@@ -7073,11 +7123,11 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
                ST.prev_eval = cur_eval;
                cur_eval = st;
                /* now continue from first node in postoned RE */
-               PUSH_YES_STATE_GOTO(EVAL_AB, startpoint, locinput);
+               PUSH_YES_STATE_GOTO(EVAL_postponed_AB, startpoint, locinput);
                NOT_REACHED; /* NOTREACHED */
        }
 
-       case EVAL_AB: /* cleanup after a successful (??{A})B */
+       case EVAL_postponed_AB: /* cleanup after a successful (??{A})B */
             /* note: this is called twice; first after popping B, then A */
             DEBUG_STACK_r({
                 Perl_re_exec_indentf( aTHX_  "EVAL_AB cur_eval=%p prev_eval=%p\n",
@@ -7123,7 +7173,11 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
            sayYES;
 
 
-       case EVAL_AB_fail: /* unsuccessfully ran A or B in (??{A})B */
+       case EVAL_B_fail: /* unsuccessful B in (?{...})B */
+           REGCP_UNWIND(ST.lastcp);
+            sayNO;
+
+       case EVAL_postponed_AB_fail: /* unsuccessfully ran A or B in (??{A})B */
            /* note: this is called twice; first after popping B, then A */
             DEBUG_STACK_r({
                 Perl_re_exec_indentf( aTHX_  "EVAL_AB_fail cur_eval=%p prev_eval=%p\n",
@@ -7523,9 +7577,6 @@ NULL
            if (cur_curlyx->u.curlyx.minmod) {
                ST.save_curlyx = cur_curlyx;
                cur_curlyx = cur_curlyx->u.curlyx.prev_curlyx;
-                ST.cp = regcppush(rex, ST.save_curlyx->u.curlyx.parenfloor,
-                            maxopenparen);
-               REGCP_SET(ST.lastcp);
                PUSH_YES_STATE_GOTO(WHILEM_B_min, ST.save_curlyx->u.curlyx.B,
                                     locinput);
                NOT_REACHED; /* NOTREACHED */
@@ -7558,11 +7609,11 @@ NULL
            CACHEsayNO;
            NOT_REACHED; /* NOTREACHED */
 
-       case WHILEM_A_min_fail: /* just failed to match A in a minimal match */
-           /* FALLTHROUGH */
        case WHILEM_A_pre_fail: /* just failed to match even minimal A */
            REGCP_UNWIND(ST.lastcp);
             regcppop(rex, &maxopenparen);
+           /* FALLTHROUGH */
+       case WHILEM_A_min_fail: /* just failed to match A in a minimal match */
            cur_curlyx->u.curlyx.lastloc = ST.save_lastloc;
            cur_curlyx->u.curlyx.count--;
            CACHEsayNO;
@@ -7595,8 +7646,6 @@ NULL
 
        case WHILEM_B_min_fail: /* just failed to match B in a minimal match */
            cur_curlyx = ST.save_curlyx;
-           REGCP_UNWIND(ST.lastcp);
-            regcppop(rex, &maxopenparen);
 
            if (cur_curlyx->u.curlyx.count >= /*max*/ARG2(cur_curlyx->u.curlyx.me)) {
                /* Maximum greed exceeded */
@@ -7618,9 +7667,6 @@ NULL
            );
            /* Try grabbing another A and see if it helps. */
            cur_curlyx->u.curlyx.lastloc = locinput;
-            ST.cp = regcppush(rex, cur_curlyx->u.curlyx.parenfloor,
-                            maxopenparen);
-           REGCP_SET(ST.lastcp);
            PUSH_STATE_GOTO(WHILEM_A_min,
                /*A*/ NEXTOPER(ST.save_curlyx->u.curlyx.me) + EXTRA_STEP_2ARGS,
                 locinput);
@@ -8225,7 +8271,7 @@ NULL
 
                 SET_RECURSE_LOCINPUT("FAKE-END[after]", cur_eval->locinput);
 
-                PUSH_YES_STATE_GOTO(EVAL_AB, st->u.eval.prev_eval->u.eval.B,
+                PUSH_YES_STATE_GOTO(EVAL_postponed_AB, st->u.eval.prev_eval->u.eval.B,
                                     locinput); /* match B */
            }
 
@@ -8482,16 +8528,17 @@ NULL
            DEBUG_STACK_r({
                regmatch_state *cur = st;
                regmatch_state *curyes = yes_state;
-               int curd = depth;
+               U32 i;
                regmatch_slab *slab = PL_regmatch_slab;
-                for (;curd > -1 && (depth-curd < 3);cur--,curd--) {
+                for (i = 0; i < 3 && i <= depth; cur--,i++) {
                     if (cur < SLAB_FIRST(slab)) {
                        slab = slab->prev;
                        cur = SLAB_LAST(slab);
                     }
-                    Perl_re_exec_indentf( aTHX_ "#%-3d %-10s %s\n",
+                    Perl_re_exec_indentf( aTHX_ "%4s #%-3d %-10s %s\n",
                         depth,
-                        curd, PL_reg_name[cur->resume_state],
+                        i ? "    " : "push",
+                        depth - i, PL_reg_name[cur->resume_state],
                         (curyes == cur) ? "yes" : ""
                     );
                     if (curyes == cur)
@@ -8643,9 +8690,12 @@ NULL
 
     if (last_pushed_cv) {
        dSP;
+        /* see "Some notes about MULTICALL" above */
        POP_MULTICALL;
         PERL_UNUSED_VAR(SP);
     }
+    else
+        LEAVE_SCOPE(orig_savestack_ix);
 
     assert(!result ||  locinput - reginfo->strbeg >= 0);
     return result ?  locinput - reginfo->strbeg : -1;
@@ -9705,6 +9755,8 @@ S_to_byte_substr(pTHX_ regexp *prog)
     return TRUE;
 }
 
+#ifndef PERL_IN_XSUB_RE
+
 bool
 Perl__is_grapheme(pTHX_ const U8 * strbeg, const U8 * s, const U8 * strend, const UV cp)
 {
@@ -9760,6 +9812,7 @@ Perl__is_grapheme(pTHX_ const U8 * strbeg, const U8 * s, const U8 * strend, cons
     return isGCB(cp_gcb_val, next_cp_gcb_val, strbeg, s, TRUE);
 }
 
+#endif