From: Father Chrysostomos Date: Mon, 12 Nov 2012 06:16:35 +0000 (-0800) Subject: [perl #43077] Make goto &sub leave @_ alone X-Git-Tag: v5.17.6~114 X-Git-Url: https://perl5.git.perl.org/perl5.git/commitdiff_plain/049bd5ffd62b73325d4b2e75e59ba04b3569137d [perl #43077] Make goto &sub leave @_ alone It is a little tricky, as we have to hang on to @_ while unwinding the effects of local @_. --- diff --git a/pp_ctl.c b/pp_ctl.c index 0ca5f2b..6849f88 100644 --- a/pp_ctl.c +++ b/pp_ctl.c @@ -2770,10 +2770,8 @@ PP(pp_goto) I32 cxix; PERL_CONTEXT *cx; CV *cv = MUTABLE_CV(SvRV(sv)); - SV** mark; - I32 items = 0; + AV *arg = GvAV(PL_defgv); I32 oldsave; - bool reified = 0; retry: if (!CvROOT(cv) && !CvXSUB(cv)) { @@ -2818,33 +2816,20 @@ PP(pp_goto) else if (CxMULTICALL(cx)) DIE(aTHX_ "Can't goto subroutine from a sort sub (or similar callback)"); if (CxTYPE(cx) == CXt_SUB && CxHASARGS(cx)) { - /* put @_ back onto stack */ AV* av = cx->blk_sub.argarray; - items = AvFILLp(av) + 1; - EXTEND(SP, items+1); /* @_ could have been extended. */ - Copy(AvARRAY(av), SP + 1, items, SV*); - SvREFCNT_dec(GvAV(PL_defgv)); - GvAV(PL_defgv) = cx->blk_sub.savearray; - CLEAR_ARGARRAY(av); - /* abandon @_ if it got reified */ - if (AvREAL(av)) { - reified = 1; + /* abandon the original @_ if it got reified or if it is + the same as the current @_ */ + if (AvREAL(av) || av == arg) { SvREFCNT_dec(av); av = newAV(); - av_extend(av, items-1); AvREIFY_only(av); PAD_SVl(0) = MUTABLE_SV(cx->blk_sub.argarray = av); } + else CLEAR_ARGARRAY(av); } - else if (CvISXSUB(cv)) { /* put GvAV(defgv) back onto stack */ - AV* const av = GvAV(PL_defgv); - items = AvFILLp(av) + 1; - EXTEND(SP, items+1); /* @_ could have been extended. */ - Copy(AvARRAY(av), SP + 1, items, SV*); - } - mark = SP; - SP += items; + /* We donate this refcount later to the callee’s pad. */ + SvREFCNT_inc_simple_void(arg); if (CxTYPE(cx) == CXt_SUB && !(CvDEPTH(cx->blk_sub.cv) = cx->blk_sub.olddepth)) SvREFCNT_dec(cx->blk_sub.cv); @@ -2855,6 +2840,7 @@ PP(pp_goto) * our precious cv. See bug #99850. */ if (!CvROOT(cv) && !CvXSUB(cv)) { const GV * const gv = CvGV(cv); + SvREFCNT_dec(arg); if (gv) { SV * const tmpstr = sv_newmortal(); gv_efullname3(tmpstr, gv, NULL); @@ -2871,10 +2857,25 @@ PP(pp_goto) OP* const retop = cx->blk_sub.retop; SV **newsp PERL_UNUSED_DECL; I32 gimme PERL_UNUSED_DECL; - if (reified) { + const SSize_t items = AvFILLp(arg) + 1; + SV** mark; + + /* put GvAV(defgv) back onto stack */ + EXTEND(SP, items+1); /* @_ could have been extended. */ + Copy(AvARRAY(arg), SP + 1, items, SV*); + mark = SP; + SP += items; + if (AvREAL(arg)) { I32 index; for (index=0; indexblk_sub.savearray; + SvREFCNT_dec(arg); } /* XS subs don't have a CxSUB, so pop it */ @@ -2909,41 +2910,26 @@ PP(pp_goto) PAD_SET_CUR_NOSAVE(padlist, CvDEPTH(cv)); if (CxHASARGS(cx)) { - AV *const av = MUTABLE_AV(PAD_SVl(0)); - - cx->blk_sub.savearray = GvAV(PL_defgv); - GvAV(PL_defgv) = MUTABLE_AV(SvREFCNT_inc_simple(av)); CX_CURPAD_SAVE(cx->blk_sub); - cx->blk_sub.argarray = av; - if (items >= AvMAX(av) + 1) { - SV **ary = AvALLOC(av); - if (AvARRAY(av) != ary) { - AvMAX(av) += AvARRAY(av) - AvALLOC(av); - AvARRAY(av) = ary; - } - if (items >= AvMAX(av) + 1) { - AvMAX(av) = items - 1; - Renew(ary,items+1,SV*); - AvALLOC(av) = ary; - AvARRAY(av) = ary; - } - } - ++mark; - Copy(mark,AvARRAY(av),items,SV*); - AvFILLp(av) = items - 1; - assert(!AvREAL(av)); - if (reified) { - /* transfer 'ownership' of refcnts to new @_ */ - AvREAL_on(av); - AvREIFY_off(av); - } - while (items--) { - if (*mark) - SvTEMP_off(*mark); - mark++; + /* cx->blk_sub.argarray has no reference count, so we + need something to hang on to our argument array so + that cx->blk_sub.argarray does not end up pointing + to freed memory as the result of undef *_. So put + it in the callee’s pad, donating our refer- + ence count. */ + SvREFCNT_dec(PAD_SVl(0)); + PAD_SVl(0) = (SV *)(cx->blk_sub.argarray = arg); + + /* GvAV(PL_defgv) might have been modified on scope + exit, so restore it. */ + if (arg != GvAV(PL_defgv)) { + AV * const av = GvAV(PL_defgv); + GvAV(PL_defgv) = (AV *)SvREFCNT_inc_simple(arg); + SvREFCNT_dec(av); } } + else SvREFCNT_dec(arg); if (PERLDB_SUB) { /* Checking curstash breaks DProf. */ Perl_get_db_sub(aTHX_ NULL, cv); if (PERLDB_GOTO) { diff --git a/t/op/goto.t b/t/op/goto.t index c9aadbc..7dafb2a 100644 --- a/t/op/goto.t +++ b/t/op/goto.t @@ -10,7 +10,7 @@ BEGIN { use warnings; use strict; -plan tests => 85; +plan tests => 88; our $TODO; my $deprecated = 0; @@ -460,12 +460,27 @@ a32039(); # goto &foo not allowed in evals - sub null { 1 }; eval 'goto &null'; like($@, qr/Can't goto subroutine from an eval-string/, 'eval string'); eval { goto &null }; like($@, qr/Can't goto subroutine from an eval-block/, 'eval block'); + +# goto &foo leaves @_ alone when called from a sub +sub returnarg { $_[0] }; +is sub { + local *_ = ["ick and queasy"]; + goto &returnarg; +}->("quick and easy"), "ick and queasy", + 'goto &foo with *_{ARRAY} replaced'; +my @__ = "\xc4\x80"; +sub { local *_ = \@__; goto &utf8::decode }->("no thinking aloud"); +is "@__", chr 256, 'goto &xsub with replaced *_{ARRAY}'; + +# And goto &foo should leave reified @_ alone +sub { *__ = \@_; goto &null } -> ("rough and tubbery"); +is ${*__}[0], 'rough and tubbery', 'goto &foo leaves reified @_ alone'; + # [perl #36521] goto &foo in warn handler could defeat recursion avoider