X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=pp_ctl.c;h=e69107e87413ae1718d20588e606f66706cffa65;hb=8cf8bfae8ab20c53dc9b668f5e3be813b5d11cb0;hp=c62ce2689a129602d5d3bf0911dedcfbf7028e34;hpb=dc35ab6e9838269debf9973a573bbd31031f3f31;p=p5sagit%2Fp5-mst-13.2.git

diff --git a/pp_ctl.c b/pp_ctl.c
index c62ce26..e69107e 100644
--- a/pp_ctl.c
+++ b/pp_ctl.c
@@ -93,36 +93,63 @@ PP(pp_regcomp)
 	RETURN;
     }
 #endif
+
+#define tryAMAGICregexp(rx)			\
+    STMT_START {				\
+	if (SvROK(rx) && SvAMAGIC(rx)) {	\
+	    SV *sv = AMG_CALLun(rx, regexp);	\
+	    if (sv) {				\
+		if (SvROK(sv))			\
+		    sv = SvRV(sv);		\
+		if (SvTYPE(sv) != SVt_REGEXP)	\
+		    Perl_croak(aTHX_ "Overloaded qr did not return a REGEXP"); \
+		rx = sv;			\
+	    }					\
+	}					\
+    } STMT_END
+	    
+
     if (PL_op->op_flags & OPf_STACKED) {
 	/* multiple args; concatentate them */
 	dMARK; dORIGMARK;
 	tmpstr = PAD_SV(ARGTARG);
 	sv_setpvs(tmpstr, "");
 	while (++MARK <= SP) {
+	    SV *msv = *MARK;
 	    if (PL_amagic_generation) {
 		SV *sv;
-		if ((SvAMAGIC(tmpstr) || SvAMAGIC(*MARK)) &&
-		    (sv = amagic_call(tmpstr, *MARK, concat_amg, AMGf_assign)))
+
+		tryAMAGICregexp(msv);
+
+		if ((SvAMAGIC(tmpstr) || SvAMAGIC(msv)) &&
+		    (sv = amagic_call(tmpstr, msv, concat_amg, AMGf_assign)))
 		{
 		   sv_setsv(tmpstr, sv);
 		   continue;
 		}
 	    }
-	    sv_catsv(tmpstr, *MARK);
+	    sv_catsv(tmpstr, msv);
 	}
     	SvSETMAGIC(tmpstr);
 	SP = ORIGMARK;
     }
-    else
+    else {
 	tmpstr = POPs;
+	tryAMAGICregexp(tmpstr);
+    }
+
+#undef tryAMAGICregexp
 
     if (SvROK(tmpstr)) {
 	SV * const sv = SvRV(tmpstr);
 	if (SvTYPE(sv) == SVt_REGEXP)
 	    re = (REGEXP*) sv;
     }
+    else if (SvTYPE(tmpstr) == SVt_REGEXP)
+	re = (REGEXP*) tmpstr;
+
     if (re) {
-	re = reg_temp_copy(re);
+	re = reg_temp_copy(NULL, re);
 	ReREFCNT_dec(PM_GETRE(pm));
 	PM_SETRE(pm, re);
     }
@@ -969,14 +996,14 @@ PP(pp_grepstart)
     PL_stack_sp = PL_stack_base + *PL_markstack_ptr + 1;
     pp_pushmark();				/* push dst */
     pp_pushmark();				/* push src */
-    ENTER;					/* enter outer scope */
+    ENTER_with_name("grep");					/* enter outer scope */
 
     SAVETMPS;
     if (PL_op->op_private & OPpGREP_LEX)
 	SAVESPTR(PAD_SVl(PL_op->op_targ));
     else
 	SAVE_DEFSV;
-    ENTER;					/* enter inner scope */
+    ENTER_with_name("grep_item");					/* enter inner scope */
     SAVEVPTR(PL_curpm);
 
     src = PL_stack_base[*PL_markstack_ptr];
@@ -1057,13 +1084,13 @@ PP(pp_mapwhile)
 	    }
 	}
     }
-    LEAVE;					/* exit inner scope */
+    LEAVE_with_name("grep_item");					/* exit inner scope */
 
     /* All done yet? */
     if (PL_markstack_ptr[-1] > *PL_markstack_ptr) {
 
 	(void)POPMARK;				/* pop top */
-	LEAVE;					/* exit outer scope */
+	LEAVE_with_name("grep");					/* exit outer scope */
 	(void)POPMARK;				/* pop src */
 	items = --*PL_markstack_ptr - PL_markstack_ptr[-1];
 	(void)POPMARK;				/* pop dst */
@@ -1086,7 +1113,7 @@ PP(pp_mapwhile)
     else {
 	SV *src;
 
-	ENTER;					/* enter inner scope */
+	ENTER_with_name("grep_item");					/* enter inner scope */
 	SAVEVPTR(PL_curpm);
 
 	/* set $_ to the new source item */
@@ -1516,8 +1543,8 @@ Perl_qerror(pTHX_ SV *err)
 	++PL_parser->error_count;
 }
 
-OP *
-Perl_die_where(pTHX_ const char *message, STRLEN msglen)
+void
+Perl_die_where(pTHX_ SV *msv)
 {
     dVAR;
 
@@ -1525,15 +1552,17 @@ Perl_die_where(pTHX_ const char *message, STRLEN msglen)
 	I32 cxix;
 	I32 gimme;
 
-	if (message) {
+	if (msv) {
 	    if (PL_in_eval & EVAL_KEEPERR) {
                 static const char prefix[] = "\t(in cleanup) ";
 		SV * const err = ERRSV;
 		const char *e = NULL;
 		if (!SvPOK(err))
 		    sv_setpvs(err,"");
-		else if (SvCUR(err) >= sizeof(prefix)+msglen-1) {
+		else if (SvCUR(err) >= sizeof(prefix)+SvCUR(msv)-1) {
 		    STRLEN len;
+		    STRLEN msglen;
+		    const char* message = SvPV_const(msv, msglen);
 		    e = SvPV_const(err, len);
 		    e += len - msglen;
 		    if (*e != *message || strNE(e,message))
@@ -1541,16 +1570,19 @@ Perl_die_where(pTHX_ const char *message, STRLEN msglen)
 		}
 		if (!e) {
 		    STRLEN start;
-		    SvGROW(err, SvCUR(err)+sizeof(prefix)+msglen);
+		    SvGROW(err, SvCUR(err)+sizeof(prefix)+SvCUR(msv));
 		    sv_catpvn(err, prefix, sizeof(prefix)-1);
-		    sv_catpvn(err, message, msglen);
-		    start = SvCUR(err)-msglen-sizeof(prefix)+1;
+		    sv_catsv(err, msv);
+		    start = SvCUR(err)-SvCUR(msv)-sizeof(prefix)+1;
 		    Perl_ck_warner(aTHX_ packWARN(WARN_MISC), "%s",
 				   SvPVX_const(err)+start);
 		}
 	    }
 	    else {
+		STRLEN msglen;
+		const char* message = SvPV_const(msv, msglen);
 		sv_setpvn(ERRSV, message, msglen);
+		SvFLAGS(ERRSV) |= SvFLAGS(msv) & SVf_UTF8;
 	    }
 	}
 
@@ -1571,8 +1603,8 @@ Perl_die_where(pTHX_ const char *message, STRLEN msglen)
 
 	    POPBLOCK(cx,PL_curpm);
 	    if (CxTYPE(cx) != CXt_EVAL) {
-		if (!message)
-		    message = SvPVx_const(ERRSV, msglen);
+		STRLEN msglen;
+		const char* message = SvPVx_const( msv ? msv : ERRSV, msglen);
 		PerlIO_write(Perl_error_log, (const char *)"panic: die ", 11);
 		PerlIO_write(Perl_error_log, message, msglen);
 		my_exit(1);
@@ -1600,16 +1632,15 @@ Perl_die_where(pTHX_ const char *message, STRLEN msglen)
 		    *msg ? msg : "Unknown error\n");
 	    }
 	    assert(CxTYPE(cx) == CXt_EVAL);
-	    return cx->blk_eval.retop;
+	    PL_restartop = cx->blk_eval.retop;
+	    JMPENV_JUMP(3);
+	    /* NOTREACHED */
 	}
     }
-    if (!message)
-	message = SvPVx_const(ERRSV, msglen);
 
-    write_to_stderr(message, msglen);
+    write_to_stderr( msv ? msv : ERRSV );
     my_failure_exit();
     /* NOTREACHED */
-    return 0;
 }
 
 PP(pp_xor)
@@ -1827,7 +1858,7 @@ PP(pp_dbstate)
 	    /* don't do recursive DB::DB call */
 	    return NORMAL;
 
-	ENTER;
+	ENTER_with_name("sub");
 	SAVETMPS;
 
 	SAVEI32(PL_debug);
@@ -1842,7 +1873,7 @@ PP(pp_dbstate)
 	    (void)(*CvXSUB(cv))(aTHX_ cv);
 	    CvDEPTH(cv)--;
 	    FREETMPS;
-	    LEAVE;
+	    LEAVE_with_name("sub");
 	    return NORMAL;
 	}
 	else {
@@ -1870,7 +1901,7 @@ PP(pp_enteriter)
     PAD *iterdata;
 #endif
 
-    ENTER;
+    ENTER_with_name("loop1");
     SAVETMPS;
 
     if (PL_op->op_targ) {
@@ -1899,7 +1930,7 @@ PP(pp_enteriter)
     if (PL_op->op_private & OPpITER_DEF)
 	cxtype |= CXp_FOR_DEF;
 
-    ENTER;
+    ENTER_with_name("loop2");
 
     PUSHBLOCK(cx, cxtype, SP);
 #ifdef USE_ITHREADS
@@ -1996,9 +2027,9 @@ PP(pp_enterloop)
     register PERL_CONTEXT *cx;
     const I32 gimme = GIMME_V;
 
-    ENTER;
+    ENTER_with_name("loop1");
     SAVETMPS;
-    ENTER;
+    ENTER_with_name("loop2");
 
     PUSHBLOCK(cx, CXt_LOOP_PLAIN, SP);
     PUSHLOOP_PLAIN(cx, SP);
@@ -2041,8 +2072,8 @@ PP(pp_leaveloop)
     POPLOOP(cx);	/* Stack values are safe: release loop vars ... */
     PL_curpm = newpm;	/* ... and pop $1 et al */
 
-    LEAVE;
-    LEAVE;
+    LEAVE_with_name("loop2");
+    LEAVE_with_name("loop1");
 
     return NORMAL;
 }
@@ -2058,7 +2089,7 @@ PP(pp_return)
     PMOP *newpm;
     I32 optype = 0;
     SV *sv;
-    OP *retop;
+    OP *retop = NULL;
 
     const I32 cxix = dopoptosub(cxstack_ix);
 
@@ -2180,7 +2211,7 @@ PP(pp_last)
     I32 pop2 = 0;
     I32 gimme;
     I32 optype;
-    OP *nextop;
+    OP *nextop = NULL;
     SV **newsp;
     PMOP *newpm;
     SV **mark;
@@ -2503,7 +2534,7 @@ PP(pp_goto)
 		PUSHMARK(mark);
 		PUTBACK;
 		(void)(*CvXSUB(cv))(aTHX_ cv);
-		LEAVE;
+		LEAVE_with_name("sub");
 		return retop;
 	    }
 	    else {
@@ -2667,6 +2698,12 @@ PP(pp_goto)
                     DIE(aTHX_ "Can't \"goto\" into the middle of a foreach loop");
 	}
 
+	if (*enterops && enterops[1]) {
+	    I32 i = enterops[1]->op_type == OP_ENTER && in_block ? 2 : 1;
+	    if (enterops[i])
+		deprecate("\"goto\" to jump into a construct");
+	}
+
 	/* pop unwanted frames */
 
 	if (ix < cxstack_ix) {
@@ -2841,7 +2878,7 @@ Perl_sv_compile_2op(pTHX_ SV *sv, OP** startop, const char *code, PAD** padp)
 
     PERL_ARGS_ASSERT_SV_COMPILE_2OP;
 
-    ENTER;
+    ENTER_with_name("eval");
     lex_start(sv, NULL, FALSE);
     SAVETMPS;
     /* switch to eval mode */
@@ -2902,7 +2939,7 @@ Perl_sv_compile_2op(pTHX_ SV *sv, OP** startop, const char *code, PAD** padp)
     lex_end();
     /* XXX DAPM do this properly one year */
     *padp = MUTABLE_AV(SvREFCNT_inc_simple(PL_comppad));
-    LEAVE;
+    LEAVE_with_name("eval");
     if (IN_PERL_COMPILETIME)
 	CopHINTS_set(&PL_compiling, PL_hints);
 #ifdef OP_IN_REGISTER
@@ -3040,7 +3077,7 @@ S_doeval(pTHX_ int gimme, OP** startop, CV* outside, U32 seq)
 	    POPEVAL(cx);
 	}
 	lex_end();
-	LEAVE; /* pp_entereval knows about this LEAVE.  */
+	LEAVE_with_name("eval"); /* pp_entereval knows about this LEAVE.  */
 
 	msg = SvPVx_nolen_const(ERRSV);
 	if (optype == OP_REQUIRE) {
@@ -3073,14 +3110,8 @@ S_doeval(pTHX_ int gimme, OP** startop, CV* outside, U32 seq)
 	SAVEFREEOP(PL_eval_root);
 
     /* Set the context for this new optree.
-     * If the last op is an OP_REQUIRE, force scalar context.
-     * Otherwise, propagate the context from the eval(). */
-    if (PL_eval_root->op_type == OP_LEAVEEVAL
-	    && cUNOPx(PL_eval_root)->op_first->op_type == OP_LINESEQ
-	    && cLISTOPx(cUNOPx(PL_eval_root)->op_first)->op_last->op_type
-	    == OP_REQUIRE)
-	scalar(PL_eval_root);
-    else if ((gimme & G_WANT) == G_VOID)
+     * Propagate the context from the eval(). */
+    if ((gimme & G_WANT) == G_VOID)
 	scalarvoid(PL_eval_root);
     else if ((gimme & G_WANT) == G_ARRAY)
 	list(PL_eval_root);
@@ -3246,9 +3277,9 @@ PP(pp_require)
 		vcmp(sv, sv_2mortal(upg_version(newSVnv(5.009005), FALSE))) >= 0) {
 	    SV *const importsv = vnormal(sv);
 	    *SvPVX_mutable(importsv) = ':';
-	    ENTER;
+	    ENTER_with_name("load_feature");
 	    Perl_load_module(aTHX_ 0, newSVpvs("feature"), NULL, importsv, NULL);
-	    LEAVE;
+	    LEAVE_with_name("load_feature");
 	}
 	/* If a version >= 5.11.0 is requested, strictures are on by default! */
 	if (PL_compcv &&
@@ -3331,7 +3362,7 @@ PP(pp_require)
 		    tryname = SvPVX_const(namesv);
 		    tryrsfp = NULL;
 
-		    ENTER;
+		    ENTER_with_name("call_INC");
 		    SAVETMPS;
 		    EXTEND(SP, 2);
 
@@ -3409,7 +3440,7 @@ PP(pp_require)
 
 		    PUTBACK;
 		    FREETMPS;
-		    LEAVE;
+		    LEAVE_with_name("call_INC");
 
 		    if (tryrsfp) {
 			hook_sv = dirsv;
@@ -3556,7 +3587,7 @@ PP(pp_require)
 			   unixname, unixlen, SvREFCNT_inc_simple(hook_sv), 0 );
     }
 
-    ENTER;
+    ENTER_with_name("eval");
     SAVETMPS;
     lex_start(NULL, tryrsfp, TRUE);
 
@@ -3573,11 +3604,14 @@ PP(pp_require)
         PL_compiling.cop_warnings = pWARN_STD ;
 
     if (filter_sub || filter_cache) {
-	SV * const datasv = filter_add(S_run_user_filter, NULL);
+	/* We can use the SvPV of the filter PVIO itself as our cache, rather
+	   than hanging another SV from it. In turn, filter_add() optionally
+	   takes the SV to use as the filter (or creates a new SV if passed
+	   NULL), so simply pass in whatever value filter_cache has.  */
+	SV * const datasv = filter_add(S_run_user_filter, filter_cache);
 	IoLINES(datasv) = filter_has_file;
 	IoTOP_GV(datasv) = MUTABLE_GV(filter_state);
 	IoBOTTOM_GV(datasv) = MUTABLE_GV(filter_sub);
-	IoFMT_GV(datasv) = MUTABLE_GV(filter_cache);
     }
 
     /* switch to eval mode */
@@ -3640,7 +3674,7 @@ PP(pp_entereval)
     TAINT_IF(SvTAINTED(sv));
     TAINT_PROPER("eval");
 
-    ENTER;
+    ENTER_with_name("eval");
     lex_start(sv, NULL, FALSE);
     SAVETMPS;
 
@@ -3784,7 +3818,7 @@ PP(pp_leaveeval)
 	/* die_where() did LEAVE, or we won't be here */
     }
     else {
-	LEAVE;
+	LEAVE_with_name("eval");
 	if (!(save_flags & OPf_SPECIAL)) {
 	    CLEAR_ERRSV();
 	}
@@ -3807,7 +3841,7 @@ Perl_delete_eval_scope(pTHX)
     POPBLOCK(cx,newpm);
     POPEVAL(cx);
     PL_curpm = newpm;
-    LEAVE;
+    LEAVE_with_name("eval_scope");
     PERL_UNUSED_VAR(newsp);
     PERL_UNUSED_VAR(gimme);
     PERL_UNUSED_VAR(optype);
@@ -3821,7 +3855,7 @@ Perl_create_eval_scope(pTHX_ U32 flags)
     PERL_CONTEXT *cx;
     const I32 gimme = GIMME_V;
 	
-    ENTER;
+    ENTER_with_name("eval_scope");
     SAVETMPS;
 
     PUSHBLOCK(cx, (CXt_EVAL|CXp_TRYBLOCK), PL_stack_sp);
@@ -3889,7 +3923,7 @@ PP(pp_leavetry)
     }
     PL_curpm = newpm;	/* Don't pop $1 et al till now */
 
-    LEAVE;
+    LEAVE_with_name("eval_scope");
     CLEAR_ERRSV();
     RETURN;
 }
@@ -3900,7 +3934,7 @@ PP(pp_entergiven)
     register PERL_CONTEXT *cx;
     const I32 gimme = GIMME_V;
     
-    ENTER;
+    ENTER_with_name("given");
     SAVETMPS;
 
     sv_setsv(PAD_SV(PL_op->op_targ), POPs);
@@ -3928,7 +3962,7 @@ PP(pp_leavegiven)
 
     PL_curpm = newpm;   /* pop $1 et al */
 
-    LEAVE;
+    LEAVE_with_name("given");
 
     return NORMAL;
 }
@@ -3945,7 +3979,7 @@ S_make_matcher(pTHX_ REGEXP *re)
     PM_SETRE(matcher, ReREFCNT_inc(re));
 
     SAVEFREEOP((OP *) matcher);
-    ENTER; SAVETMPS;
+    ENTER_with_name("matcher"); SAVETMPS;
     SAVEOP();
     return matcher;
 }
@@ -3975,7 +4009,7 @@ S_destroy_matcher(pTHX_ PMOP *matcher)
     PERL_UNUSED_ARG(matcher);
 
     FREETMPS;
-    LEAVE;
+    LEAVE_with_name("matcher");
 }
 
 /* Do a smart match */
@@ -4062,7 +4096,7 @@ S_do_smartmatch(pTHX_ HV *seen_this, HV *seen_other)
 		RETPUSHYES;
 	    while ( (he = hv_iternext(hv)) ) {
 		DEBUG_M(Perl_deb(aTHX_ "        testing hash key...\n"));
-		ENTER;
+		ENTER_with_name("smartmatch_hash_key_test");
 		SAVETMPS;
 		PUSHMARK(SP);
 		PUSHs(hv_iterkeysv(he));
@@ -4074,7 +4108,7 @@ S_do_smartmatch(pTHX_ HV *seen_this, HV *seen_other)
 		else
 		    andedresults = SvTRUEx(POPs) && andedresults;
 		FREETMPS;
-		LEAVE;
+		LEAVE_with_name("smartmatch_hash_key_test");
 	    }
 	    if (andedresults)
 		RETPUSHYES;
@@ -4093,7 +4127,7 @@ S_do_smartmatch(pTHX_ HV *seen_this, HV *seen_other)
 	    for (i = 0; i <= len; ++i) {
 		SV * const * const svp = av_fetch(av, i, FALSE);
 		DEBUG_M(Perl_deb(aTHX_ "        testing array element...\n"));
-		ENTER;
+		ENTER_with_name("smartmatch_array_elem_test");
 		SAVETMPS;
 		PUSHMARK(SP);
 		if (svp)
@@ -4106,7 +4140,7 @@ S_do_smartmatch(pTHX_ HV *seen_this, HV *seen_other)
 		else
 		    andedresults = SvTRUEx(POPs) && andedresults;
 		FREETMPS;
-		LEAVE;
+		LEAVE_with_name("smartmatch_array_elem_test");
 	    }
 	    if (andedresults)
 		RETPUSHYES;
@@ -4116,7 +4150,7 @@ S_do_smartmatch(pTHX_ HV *seen_this, HV *seen_other)
 	else {
 	  sm_any_sub:
 	    DEBUG_M(Perl_deb(aTHX_ "    applying rule Any-CodeRef\n"));
-	    ENTER;
+	    ENTER_with_name("smartmatch_coderef");
 	    SAVETMPS;
 	    PUSHMARK(SP);
 	    PUSHs(d);
@@ -4128,7 +4162,7 @@ S_do_smartmatch(pTHX_ HV *seen_this, HV *seen_other)
 	    else if (SvTEMP(TOPs))
 		SvREFCNT_inc_void(TOPs);
 	    FREETMPS;
-	    LEAVE;
+	    LEAVE_with_name("smartmatch_coderef");
 	    RETURN;
 	}
     }
@@ -4473,7 +4507,7 @@ PP(pp_enterwhen)
     if ((0 == (PL_op->op_flags & OPf_SPECIAL)) && !SvTRUEx(POPs))
 	return cLOGOP->op_other->op_next;
 
-    ENTER;
+    ENTER_with_name("eval");
     SAVETMPS;
 
     PUSHBLOCK(cx, CXt_WHEN, SP);
@@ -4498,7 +4532,7 @@ PP(pp_leavewhen)
 
     PL_curpm = newpm;   /* pop $1 et al */
 
-    LEAVE;
+    LEAVE_with_name("eval");
     return NORMAL;
 }
 
@@ -4815,8 +4849,8 @@ S_run_user_filter(pTHX_ int idx, SV *buf_sv, int maxlen)
     int status = 0;
     SV *upstream;
     STRLEN got_len;
-    const char *got_p = NULL;
-    const char *prune_from = NULL;
+    char *got_p = NULL;
+    char *prune_from = NULL;
     bool read_from_cache = FALSE;
     STRLEN umaxlen;
 
@@ -4830,8 +4864,8 @@ S_run_user_filter(pTHX_ int idx, SV *buf_sv, int maxlen)
        for PL_parser->error_count == 0.)  Solaris doesn't segfault --
        not sure where the trouble is yet.  XXX */
 
-    if (IoFMT_GV(datasv)) {
-	SV *const cache = MUTABLE_SV(IoFMT_GV(datasv));
+    {
+	SV *const cache = datasv;
 	if (SvOK(cache)) {
 	    STRLEN cache_len;
 	    const char *cache_p = SvPV(cache, cache_len);
@@ -4885,7 +4919,7 @@ S_run_user_filter(pTHX_ int idx, SV *buf_sv, int maxlen)
 	dSP;
 	int count;
 
-	ENTER;
+	ENTER_with_name("call_filter_sub");
 	SAVE_DEFSV;
 	SAVETMPS;
 	EXTEND(SP, 2);
@@ -4909,7 +4943,7 @@ S_run_user_filter(pTHX_ int idx, SV *buf_sv, int maxlen)
 
 	PUTBACK;
 	FREETMPS;
-	LEAVE;
+	LEAVE_with_name("call_filter_sub");
     }
 
     if(SvOK(upstream)) {
@@ -4919,8 +4953,7 @@ S_run_user_filter(pTHX_ int idx, SV *buf_sv, int maxlen)
 		prune_from = got_p + umaxlen;
 	    }
 	} else {
-	    const char *const first_nl =
-		(const char *)memchr(got_p, '\n', got_len);
+	    char *const first_nl = (char *)memchr(got_p, '\n', got_len);
 	    if (first_nl && first_nl + 1 < got_p + got_len) {
 		/* There's a second line here... */
 		prune_from = first_nl + 1;
@@ -4930,11 +4963,9 @@ S_run_user_filter(pTHX_ int idx, SV *buf_sv, int maxlen)
     if (prune_from) {
 	/* Oh. Too long. Stuff some in our cache.  */
 	STRLEN cached_len = got_p + got_len - prune_from;
-	SV *cache = MUTABLE_SV(IoFMT_GV(datasv));
+	SV *const cache = datasv;
 
-	if (!cache) {
-	    IoFMT_GV(datasv) = MUTABLE_GV((cache = newSV(got_len - umaxlen)));
-	} else if (SvOK(cache)) {
+	if (SvOK(cache)) {
 	    /* Cache should be empty.  */
 	    assert(!SvCUR(cache));
 	}
@@ -4948,6 +4979,7 @@ S_run_user_filter(pTHX_ int idx, SV *buf_sv, int maxlen)
 	    SvUTF8_on(cache);
 	}
 	SvCUR_set(upstream, got_len - cached_len);
+	*prune_from = 0;
 	/* Can't yet be EOF  */
 	if (status == 0)
 	    status = 1;
@@ -4963,7 +4995,6 @@ S_run_user_filter(pTHX_ int idx, SV *buf_sv, int maxlen)
 
     if (status <= 0) {
 	IoLINES(datasv) = 0;
-	SvREFCNT_dec(IoFMT_GV(datasv));
 	if (filter_state) {
 	    SvREFCNT_dec(filter_state);
 	    IoTOP_GV(datasv) = NULL;