From: David Mitchell Date: Tue, 25 May 2010 10:38:35 +0000 (+0100) Subject: add OPpDEREFed flag to avoid double mg_get() X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=0824d66743a706cd;p=p5sagit%2Fp5-mst-13.2.git add OPpDEREFed flag to avoid double mg_get() The previous commit made various ops such as rv2av unconditionally do an SvGETMAGIC(). Under some circumstances this could cause a double mg_get() (and hence double FETCH etc). In particular, when the proceeding op was something like aelem with OPpDEREF, the aelem would call vivify_ref(), which would call magic. So in peep(), mark OP_RV2[SAH]V ops with the new OPpDEREFed flag if the preceding op was OPpDEREF. Then use this flag to avoid a second dose of magic. Note that RV2GV probably needs this flag too, but there weren't any spare private flag bits left for that op (I think). --- diff --git a/dump.c b/dump.c index 631f37c..46af01a 100644 --- a/dump.c +++ b/dump.c @@ -928,6 +928,11 @@ Perl_do_op_dump(pTHX_ I32 level, PerlIO *file, const OP *o) if (o->op_private & OPpMAYBE_LVSUB) sv_catpv(tmpsv, ",MAYBE_LVSUB"); } + + if ((optype==OP_RV2SV || optype==OP_RV2AV || optype==OP_RV2HV) + && (o->op_private & OPpDEREFed)) + sv_catpv(tmpsv, ",DEREFed"); + if (optype == OP_AELEM || optype == OP_HELEM) { if (o->op_private & OPpLVAL_DEFER) sv_catpv(tmpsv, ",LVAL_DEFER"); diff --git a/ext/B/B/Concise.pm b/ext/B/B/Concise.pm index 2699605..04e93cd 100644 --- a/ext/B/B/Concise.pm +++ b/ext/B/B/Concise.pm @@ -606,6 +606,7 @@ $priv{$_}{64} = "RTIME" for ("match", "subst", "substcont", "qr"); "COMPL", "GROWS"); $priv{"repeat"}{64} = "DOLIST"; $priv{"leaveloop"}{64} = "CONT"; +$priv{$_}{4} = "DREFed" for (qw(rv2sv rv2av rv2hv)); @{$priv{$_}}{32,64,96} = ("DREFAV", "DREFHV", "DREFSV") for (qw(rv2gv rv2sv padsv aelem helem)); $priv{$_}{16} = "STATE" for ("padav", "padhv", "padsv"); diff --git a/ext/B/t/f_sort.t b/ext/B/t/f_sort.t index 6a36fcb..b940345 100644 --- a/ext/B/t/f_sort.t +++ b/ext/B/t/f_sort.t @@ -518,7 +518,7 @@ checkOptree(name => q{Compound sort/map Expression }, # l <|> mapwhile(other->m)[t26] lK # m <#> gv[*_] s # n <1> rv2sv sKM/DREFAV,1 -# o <1> rv2av[t4] sKR/1 +# o <1> rv2av[t4] sKR/DEREFed,1 # p <$> const[IV 0] s # q <2> aelem sK/2 # - <@> scope lK @@ -553,7 +553,7 @@ EOT_EOT # l <|> mapwhile(other->m)[t12] lK # m <$> gv(*_) s # n <1> rv2sv sKM/DREFAV,1 -# o <1> rv2av[t2] sKR/1 +# o <1> rv2av[t2] sKR/DREFed,1 # p <$> const(IV 0) s # q <2> aelem sK/2 # - <@> scope lK diff --git a/op.c b/op.c index 40ef4bc..da0ad2c 100644 --- a/op.c +++ b/op.c @@ -8877,6 +8877,20 @@ Perl_peep(pTHX_ register OP *o) } break; } + case OP_RV2SV: + case OP_RV2AV: + case OP_RV2HV: + if (oldop + && ( oldop->op_type == OP_AELEM + || oldop->op_type == OP_PADSV + || oldop->op_type == OP_RV2SV + || oldop->op_type == OP_RV2GV + || oldop->op_type == OP_HELEM + ) + && (oldop->op_private & OPpDEREF) + ) { + o->op_private |= OPpDEREFed; + } case OP_SORT: { /* will point to RV2AV or PADAV op on LHS/RHS of assign */ diff --git a/op.h b/op.h index b9327bb..b66c4a1 100644 --- a/op.h +++ b/op.h @@ -191,6 +191,8 @@ Deprecated. Use C instead. #define OPpDEREF_AV 32 /* Want ref to AV. */ #define OPpDEREF_HV 64 /* Want ref to HV. */ #define OPpDEREF_SV (32|64) /* Want ref to SV. */ +/* Private for OP_RV2SV, OP_RV2AV, OP_RV2AV */ +#define OPpDEREFed 4 /* prev op was OPpDEREF */ /* OP_ENTERSUB only */ #define OPpENTERSUB_DB 16 /* Debug subroutine. */ #define OPpENTERSUB_HASTARG 32 /* Called from OP tree. */ diff --git a/pp.c b/pp.c index d6e3132..937fdfd 100644 --- a/pp.c +++ b/pp.c @@ -272,7 +272,8 @@ PP(pp_rv2sv) dVAR; dSP; dTOPss; GV *gv = NULL; - SvGETMAGIC(sv); + if (!(PL_op->op_private & OPpDEREFed)) + SvGETMAGIC(sv); if (SvROK(sv)) { tryAMAGICunDEREF(to_sv); diff --git a/pp_hot.c b/pp_hot.c index d5c13fe..a8c06b8 100644 --- a/pp_hot.c +++ b/pp_hot.c @@ -820,7 +820,8 @@ PP(pp_rv2av) const bool is_pp_rv2av = PL_op->op_type == OP_RV2AV; const svtype type = is_pp_rv2av ? SVt_PVAV : SVt_PVHV; - SvGETMAGIC(sv); + if (!(PL_op->op_private & OPpDEREFed)) + SvGETMAGIC(sv); if (SvROK(sv)) { tryAMAGICunDEREF_var(is_pp_rv2av ? to_av_amg : to_hv_amg);