From: John Tobey Date: Fri, 20 Oct 2000 22:03:27 +0000 (-0400) Subject: Re: Creating const subs for constants. X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=beab0874143b7208922720fecefc4a224011fa25;p=p5sagit%2Fp5-mst-13.2.git Re: Creating const subs for constants. Message-Id: p4raw-id: //depot/perl@7389 --- diff --git a/cv.h b/cv.h index adb424e..6fa1f4f 100644 --- a/cv.h +++ b/cv.h @@ -75,6 +75,7 @@ Returns the stash of the CV. #define CVf_METHOD 0x0040 /* CV is explicitly marked as a method */ #define CVf_LOCKED 0x0080 /* CV locks itself or first arg on entry */ #define CVf_LVALUE 0x0100 /* CV return value can be used as lvalue */ +#define CVf_CONST 0x0200 /* inlinable sub */ #define CvCLONE(cv) (CvFLAGS(cv) & CVf_CLONE) #define CvCLONE_on(cv) (CvFLAGS(cv) |= CVf_CLONE) @@ -122,3 +123,7 @@ Returns the stash of the CV. #define CvSPECIAL(cv) (CvUNIQUE(cv) && SvFAKE(cv)) #define CvSPECIAL_on(cv) (CvUNIQUE_on(cv),SvFAKE_on(cv)) #define CvSPECIAL_off(cv) (CvUNIQUE_off(cv),SvFAKE_off(cv)) + +#define CvCONST(cv) (CvFLAGS(cv) & CVf_CONST) +#define CvCONST_on(cv) (CvFLAGS(cv) |= CVf_CONST) +#define CvCONST_off(cv) (CvFLAGS(cv) &= ~CVf_CONST) diff --git a/embed.pl b/embed.pl index e846cac..f685042 100755 --- a/embed.pl +++ b/embed.pl @@ -1441,7 +1441,7 @@ Afnp |int |fprintf_nocontext|PerlIO* stream|const char* fmt|... #endif p |void |cv_ckproto |CV* cv|GV* gv|char* p p |CV* |cv_clone |CV* proto -Ap |SV* |cv_const_sv |CV* cv +Apd |SV* |cv_const_sv |CV* cv p |SV* |op_const_sv |OP* o|CV* cv Ap |void |cv_undef |CV* cv Ap |void |cx_dump |PERL_CONTEXT* cs @@ -1761,7 +1761,7 @@ Ap |OP* |newANONHASH |OP* o Ap |OP* |newANONSUB |I32 floor|OP* proto|OP* block Ap |OP* |newASSIGNOP |I32 flags|OP* left|I32 optype|OP* right Ap |OP* |newCONDOP |I32 flags|OP* expr|OP* trueop|OP* falseop -Apd |void |newCONSTSUB |HV* stash|char* name|SV* sv +Apd |CV* |newCONSTSUB |HV* stash|char* name|SV* sv Ap |void |newFORM |I32 floor|OP* o|OP* block Ap |OP* |newFOROP |I32 flags|char* label|line_t forline \ |OP* sclr|OP* expr|OP*block|OP*cont diff --git a/op.c b/op.c index 84a1df9..6ef4bfe 100644 --- a/op.c +++ b/op.c @@ -4112,6 +4112,10 @@ Perl_cv_undef(pTHX_ CV *cv) CvGV(cv) = Nullgv; SvREFCNT_dec(CvOUTSIDE(cv)); CvOUTSIDE(cv) = Nullcv; + if (CvCONST(cv)) { + SvREFCNT_dec((SV*)CvXSUBANY(cv).any_ptr); + CvCONST_off(cv); + } if (CvPADLIST(cv)) { /* may be during global destruction */ if (SvREFCNT(CvPADLIST(cv))) { @@ -4312,6 +4316,15 @@ S_cv_clone2(pTHX_ CV *proto, CV *outside) #endif LEAVE; + + if (CvCONST(cv)) { + SV* const_sv = op_const_sv(CvSTART(cv), cv); + assert(const_sv); + /* constant sub () { $x } closing over $x - see lib/constant.pm */ + SvREFCNT_dec(cv); + cv = newCONSTSUB(CvSTASH(proto), 0, const_sv); + } + return cv; } @@ -4350,12 +4363,25 @@ Perl_cv_ckproto(pTHX_ CV *cv, GV *gv, char *p) } } +static void const_sv_xsub(pTHXo_ CV* cv); + +/* +=for apidoc cv_const_sv + +If C is a constant sub eligible for inlining. returns the constant +value returned by the sub. Otherwise, returns NULL. + +Constant subs can be created with C or as described in +L. + +=cut +*/ SV * Perl_cv_const_sv(pTHX_ CV *cv) { - if (!cv || !SvPOK(cv) || SvCUR(cv)) + if (!cv || !CvCONST(cv)) return Nullsv; - return op_const_sv(CvSTART(cv), cv); + return (SV*)CvXSUBANY(cv).any_ptr; } SV * @@ -4385,7 +4411,17 @@ Perl_op_const_sv(pTHX_ OP *o, CV *cv) else if ((type == OP_PADSV || type == OP_CONST) && cv) { AV* padav = (AV*)(AvARRAY(CvPADLIST(cv))[1]); sv = padav ? AvARRAY(padav)[o->op_targ] : Nullsv; - if (!sv || (!SvREADONLY(sv) && SvREFCNT(sv) > 1)) + if (!sv) + return Nullsv; + if (CvCONST(cv)) { + /* We get here only from cv_clone2() while creating a closure. + Copy the const value here instead of in cv_clone2 so that + SvREADONLY_on doesn't lead to problems when leaving + scope. + */ + sv = newSVsv(sv); + } + if (!SvREADONLY(sv) && SvREFCNT(sv) > 1) return Nullsv; } else @@ -4427,6 +4463,7 @@ Perl_newATTRSUB(pTHX_ I32 floor, OP *o, OP *proto, OP *attrs, OP *block) char *ps = proto ? SvPVx(((SVOP*)proto)->op_sv, n_a) : Nullch; register CV *cv=0; I32 ix; + SV *const_sv; name = o ? SvPVx(cSVOPo->op_sv, n_a) : Nullch; if (!name && PERLDB_NAMEANON && CopLINE(PL_curcop)) { @@ -4465,12 +4502,17 @@ Perl_newATTRSUB(pTHX_ I32 floor, OP *o, OP *proto, OP *attrs, OP *block) SvREFCNT_dec(PL_compcv); cv = PL_compcv = NULL; PL_sub_generation++; - goto noblock; + goto done; } - if (!name || GvCVGEN(gv)) - cv = Nullcv; - else if ((cv = GvCV(gv))) { + cv = (!name || GvCVGEN(gv)) ? Nullcv : GvCV(gv); + + if (!block || !ps || *ps || attrs) + const_sv = Nullsv; + else + const_sv = op_const_sv(block, Nullcv); + + if (cv) { bool exists = CvROOT(cv) || CvXSUB(cv); /* if the subroutine doesn't exist and wasn't pre-declared * with a prototype, assume it will be AUTOLOADed, @@ -4480,8 +4522,6 @@ Perl_newATTRSUB(pTHX_ I32 floor, OP *o, OP *proto, OP *attrs, OP *block) cv_ckproto(cv, gv, ps); /* already defined (or promised)? */ if (exists || GvASSUMECV(gv)) { - SV* const_sv; - bool const_changed = TRUE; if (!block && !attrs) { /* just a "sub foo;" when &foo is already defined */ SAVEFREESV(PL_compcv); @@ -4490,24 +4530,43 @@ Perl_newATTRSUB(pTHX_ I32 floor, OP *o, OP *proto, OP *attrs, OP *block) /* ahem, death to those who redefine active sort subs */ if (PL_curstackinfo->si_type == PERLSI_SORT && PL_sortcop == CvSTART(cv)) Perl_croak(aTHX_ "Can't redefine active sort subroutine %s", name); - if (!block) - goto withattrs; - if ((const_sv = cv_const_sv(cv))) - const_changed = sv_cmp(const_sv, op_const_sv(block, Nullcv)); - if ((const_sv && const_changed) || ckWARN(WARN_REDEFINE)) - { - line_t oldline = CopLINE(PL_curcop); - CopLINE_set(PL_curcop, PL_copline); - Perl_warner(aTHX_ WARN_REDEFINE, - const_sv ? "Constant subroutine %s redefined" - : "Subroutine %s redefined", name); - CopLINE_set(PL_curcop, oldline); + if (block) { + if (ckWARN(WARN_REDEFINE) + || (CvCONST(cv) + && (!const_sv || sv_cmp(cv_const_sv(cv), const_sv)))) + { + line_t oldline = CopLINE(PL_curcop); + CopLINE_set(PL_curcop, PL_copline); + Perl_warner(aTHX_ WARN_REDEFINE, + CvCONST(cv) ? "Constant subroutine %s redefined" + : "Subroutine %s redefined", name); + CopLINE_set(PL_curcop, oldline); + } + SvREFCNT_dec(cv); + cv = Nullcv; } - SvREFCNT_dec(cv); - cv = Nullcv; } } - withattrs: + if (const_sv) { + SvREFCNT_inc(const_sv); + if (cv) { + cv_undef(cv); + sv_setpv((SV*)cv, ""); /* prototype is "" */ + CvXSUBANY(cv).any_ptr = const_sv; + CvXSUB(cv) = const_sv_xsub; + CvCONST_on(cv); + /* XXX Does anybody care that CvFILE(cv) is blank? */ + } + else { + GvCV(gv) = Nullcv; + cv = newCONSTSUB(NULL, name, const_sv); + } + op_free(block); + SvREFCNT_dec(PL_compcv); + PL_compcv = NULL; + PL_sub_generation++; + goto done; + } if (attrs) { HV *stash; SV *rcv; @@ -4591,12 +4650,8 @@ Perl_newATTRSUB(pTHX_ I32 floor, OP *o, OP *proto, OP *attrs, OP *block) } } } - if (!block) { - noblock: - PL_copline = NOLINE; - LEAVE_SCOPE(floor); - return cv; - } + if (!block) + goto done; if (AvFILLp(PL_comppad_name) < AvFILLp(PL_comppad)) av_store(PL_comppad_name, AvFILLp(PL_comppad), Nullsv); @@ -4635,6 +4690,9 @@ Perl_newATTRSUB(pTHX_ I32 floor, OP *o, OP *proto, OP *attrs, OP *block) PL_curpad[ix] = Nullsv; } } + assert(!CvCONST(cv)); + if (ps && !*ps && op_const_sv(block, cv)) + CvCONST_on(cv); } else { AV *av = newAV(); /* Will be @_ */ @@ -4750,10 +4808,11 @@ eligible for inlining at compile-time. =cut */ -void +CV * Perl_newCONSTSUB(pTHX_ HV *stash, char *name, SV *sv) { dTHR; + CV* cv; ENTER; @@ -4774,15 +4833,14 @@ Perl_newCONSTSUB(pTHX_ HV *stash, char *name, SV *sv) #endif } - newATTRSUB( - start_subparse(FALSE, 0), - newSVOP(OP_CONST, 0, newSVpv(name,0)), - newSVOP(OP_CONST, 0, &PL_sv_no), /* SvPV(&PL_sv_no) == "" -- GMB */ - Nullop, - newSTATEOP(0, Nullch, newSVOP(OP_CONST, 0, sv)) - ); + cv = newXS(name, const_sv_xsub, __FILE__); + CvXSUBANY(cv).any_ptr = sv; + CvCONST_on(cv); + sv_setpv((SV*)cv, ""); /* prototype is "" */ LEAVE; + + return cv; } /* @@ -4814,7 +4872,10 @@ Perl_newXS(pTHX_ char *name, XSUBADDR_t subaddr, char *filename) line_t oldline = CopLINE(PL_curcop); if (PL_copline != NOLINE) CopLINE_set(PL_curcop, PL_copline); - Perl_warner(aTHX_ WARN_REDEFINE, "Subroutine %s redefined",name); + Perl_warner(aTHX_ WARN_REDEFINE, + CvCONST(cv) ? "Constant subroutine %s redefined" + : "Subroutine %s redefined" + ,name); CopLINE_set(PL_curcop, oldline); } SvREFCNT_dec(cv); @@ -6843,3 +6904,14 @@ Perl_peep(pTHX_ register OP *o) } LEAVE; } + +#include "XSUB.h" + +/* Efficient sub that returns a constant scalar value. */ +static void +const_sv_xsub(pTHXo_ CV* cv) +{ + dXSARGS; + ST(0) = sv_2mortal(newSVsv((SV*)XSANY.any_ptr)); + XSRETURN(1); +} diff --git a/perlapi.c b/perlapi.c index 9eb4175..3cfe4e0 100644 --- a/perlapi.c +++ b/perlapi.c @@ -1743,10 +1743,10 @@ Perl_newCONDOP(pTHXo_ I32 flags, OP* expr, OP* trueop, OP* falseop) } #undef Perl_newCONSTSUB -void +CV* Perl_newCONSTSUB(pTHXo_ HV* stash, char* name, SV* sv) { - ((CPerlObj*)pPerl)->Perl_newCONSTSUB(stash, name, sv); + return ((CPerlObj*)pPerl)->Perl_newCONSTSUB(stash, name, sv); } #undef Perl_newFORM diff --git a/pod/perlapi.pod b/pod/perlapi.pod index 98abdc1..a5178e8 100644 --- a/pod/perlapi.pod +++ b/pod/perlapi.pod @@ -287,6 +287,19 @@ Returns the stash of the CV. =for hackers Found in file cv.h +=item cv_const_sv + +If C is a constant sub eligible for inlining. returns the constant +value returned by the sub. Otherwise, returns NULL. + +Constant subs can be created with C or as described in +L. + + SV* cv_const_sv(CV* cv) + +=for hackers +Found in file op.c + =item dMARK Declare a stack marker variable, C, for the XSUB. See C and @@ -1162,7 +1175,7 @@ Found in file handy.h Creates a constant sub equivalent to Perl C which is eligible for inlining at compile-time. - void newCONSTSUB(HV* stash, char* name, SV* sv) + CV* newCONSTSUB(HV* stash, char* name, SV* sv) =for hackers Found in file op.c diff --git a/proto.h b/proto.h index 59129b1..2713916 100644 --- a/proto.h +++ b/proto.h @@ -504,7 +504,7 @@ PERL_CALLCONV OP* Perl_newANONHASH(pTHX_ OP* o); PERL_CALLCONV OP* Perl_newANONSUB(pTHX_ I32 floor, OP* proto, OP* block); PERL_CALLCONV OP* Perl_newASSIGNOP(pTHX_ I32 flags, OP* left, I32 optype, OP* right); PERL_CALLCONV OP* Perl_newCONDOP(pTHX_ I32 flags, OP* expr, OP* trueop, OP* falseop); -PERL_CALLCONV void Perl_newCONSTSUB(pTHX_ HV* stash, char* name, SV* sv); +PERL_CALLCONV CV* Perl_newCONSTSUB(pTHX_ HV* stash, char* name, SV* sv); PERL_CALLCONV void Perl_newFORM(pTHX_ I32 floor, OP* o, OP* block); PERL_CALLCONV OP* Perl_newFOROP(pTHX_ I32 flags, char* label, line_t forline, OP* sclr, OP* expr, OP*block, OP*cont); PERL_CALLCONV OP* Perl_newLOGOP(pTHX_ I32 optype, I32 flags, OP* left, OP* right); diff --git a/sv.c b/sv.c index b795b29..148c762 100644 --- a/sv.c +++ b/sv.c @@ -2745,12 +2745,7 @@ Perl_sv_setsv(pTHX_ SV *dstr, register SV *sstr) if (!GvCVGEN((GV*)dstr) && (CvROOT(cv) || CvXSUB(cv))) { - SV *const_sv = cv_const_sv(cv); - bool const_changed = TRUE; - if(const_sv) - const_changed = sv_cmp(const_sv, - op_const_sv(CvSTART((CV*)sref), - (CV*)sref)); + SV *const_sv; /* ahem, death to those who redefine * active sort subs */ if (PL_curstackinfo->si_type == PERLSI_SORT && @@ -2758,11 +2753,20 @@ Perl_sv_setsv(pTHX_ SV *dstr, register SV *sstr) Perl_croak(aTHX_ "Can't redefine active sort subroutine %s", GvENAME((GV*)dstr)); - if ((const_changed && const_sv) || ckWARN(WARN_REDEFINE)) - Perl_warner(aTHX_ WARN_REDEFINE, const_sv ? - "Constant subroutine %s redefined" - : "Subroutine %s redefined", - GvENAME((GV*)dstr)); + /* Redefining a sub - warning is mandatory if + it was a const and its value changed. */ + if (ckWARN(WARN_REDEFINE) + || (CvCONST(cv) + && (!CvCONST((CV*)sref) + || sv_cmp(cv_const_sv(cv), + cv_const_sv((CV*)sref))))) + { + Perl_warner(aTHX_ WARN_REDEFINE, + CvCONST(cv) + ? "Constant subroutine %s redefined" + : "Subroutine %s redefined", + GvENAME((GV*)dstr)); + } } cv_ckproto(cv, (GV*)dstr, SvPOK(sref) ? SvPVX(sref) : Nullch);