X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=cv.h;h=74e2adec8d4320d061cf23506aad1a9a03b59643;hb=4aad327484f5f36a4e39bd7979447d47a5417a57;hp=2675ede847dac9ce32d887c3a87c4288f9d13acf;hpb=8990e3071044a96302560bbdb5706f3e74cf1bef;p=p5sagit%2Fp5-mst-13.2.git diff --git a/cv.h b/cv.h index 2675ede..74e2ade 100644 --- a/cv.h +++ b/cv.h @@ -1,42 +1,204 @@ -/* $RCSfile: cv.h,v $$Revision: 4.1 $$Date: 92/08/07 18:26:42 $ +/* cv.h * - * Copyright (c) 1991, Larry Wall + * Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1999, + * 2000, 2001, 2002, 2003, by Larry Wall and others * * You may distribute under the terms of either the GNU General Public * License or the Artistic License, as specified in the README file. * - * $Log: cv.h,v $ */ +/* This structure must match XPVCV in B/C.pm and the beginning of XPVFM + * in sv.h */ + struct xpvcv { - char * xpv_pv; /* pointer to malloced string */ + char * xpv_pv; /* pointer to malloced string (for prototype) */ STRLEN xpv_cur; /* length of xp_pv as a C string */ STRLEN xpv_len; /* allocated size */ - STRLEN xof_off; /* ptr is incremented by offset */ - double xnv_nv; /* numeric value, if any */ + IV xof_off; /* integer value */ + NV xnv_nv; /* numeric value, if any */ MAGIC* xmg_magic; /* magic for scalar array */ HV* xmg_stash; /* class package */ HV * xcv_stash; OP * xcv_start; OP * xcv_root; - I32 (*xcv_usersub)(); - I32 xcv_userindex; + void (*xcv_xsub) (pTHX_ CV*); + ANY xcv_xsubany; GV * xcv_gv; - GV * xcv_filegv; - long xcv_depth; /* >= 2 indicates recursive call */ - AV * xcv_padlist; - bool xcv_deleted; + char * xcv_file; + long xcv_depth; /* >= 2 indicates recursive call */ + PADLIST * xcv_padlist; + CV * xcv_outside; + cv_flags_t xcv_flags; + U32 xcv_outside_seq; /* the COP sequence (at the point of our + * compilation) in the lexically enclosing + * sub */ }; + +/* +=head1 Handy Values + +=for apidoc AmU||Nullcv +Null CV pointer. + +=head1 CV Manipulation Functions + +=for apidoc Am|HV*|CvSTASH|CV* cv +Returns the stash of the CV. + +=cut +*/ + #define Nullcv Null(CV*) + #define CvSTASH(sv) ((XPVCV*)SvANY(sv))->xcv_stash #define CvSTART(sv) ((XPVCV*)SvANY(sv))->xcv_start #define CvROOT(sv) ((XPVCV*)SvANY(sv))->xcv_root -#define CvUSERSUB(sv) ((XPVCV*)SvANY(sv))->xcv_usersub -#define CvUSERINDEX(sv) ((XPVCV*)SvANY(sv))->xcv_userindex +#define CvXSUB(sv) ((XPVCV*)SvANY(sv))->xcv_xsub +#define CvXSUBANY(sv) ((XPVCV*)SvANY(sv))->xcv_xsubany #define CvGV(sv) ((XPVCV*)SvANY(sv))->xcv_gv -#define CvFILEGV(sv) ((XPVCV*)SvANY(sv))->xcv_filegv +#define CvFILE(sv) ((XPVCV*)SvANY(sv))->xcv_file +#ifdef USE_ITHREADS +# define CvFILE_set_from_cop(sv, cop) (CvFILE(sv) = savepv(CopFILE(cop))) +#else +# define CvFILE_set_from_cop(sv, cop) (CvFILE(sv) = CopFILE(cop)) +#endif +#define CvFILEGV(sv) (gv_fetchfile(CvFILE(sv))) #define CvDEPTH(sv) ((XPVCV*)SvANY(sv))->xcv_depth #define CvPADLIST(sv) ((XPVCV*)SvANY(sv))->xcv_padlist -#define CvDELETED(sv) ((XPVCV*)SvANY(sv))->xcv_deleted +#define CvOUTSIDE(sv) ((XPVCV*)SvANY(sv))->xcv_outside +#define CvFLAGS(sv) ((XPVCV*)SvANY(sv))->xcv_flags +#define CvOUTSIDE_SEQ(sv) ((XPVCV*)SvANY(sv))->xcv_outside_seq + +#define CVf_CLONE 0x0001 /* anon CV uses external lexicals */ +#define CVf_CLONED 0x0002 /* a clone of one of those */ +#define CVf_ANON 0x0004 /* CvGV() can't be trusted */ +#define CVf_OLDSTYLE 0x0008 +#define CVf_UNIQUE 0x0010 /* can't be cloned */ +#define CVf_NODEBUG 0x0020 /* no DB::sub indirection for this CV + (esp. useful for special XSUBs) */ +#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 CVf_WEAKOUTSIDE 0x0400 /* CvOUTSIDE isn't ref counted */ +#define CVf_ASSERTION 0x0800 /* CV called only when asserting */ + +/* This symbol for optimised communication between toke.c and op.c: */ +#define CVf_BUILTIN_ATTRS (CVf_METHOD|CVf_LOCKED|CVf_LVALUE|CVf_ASSERTION) + +#define CvCLONE(cv) (CvFLAGS(cv) & CVf_CLONE) +#define CvCLONE_on(cv) (CvFLAGS(cv) |= CVf_CLONE) +#define CvCLONE_off(cv) (CvFLAGS(cv) &= ~CVf_CLONE) + +#define CvCLONED(cv) (CvFLAGS(cv) & CVf_CLONED) +#define CvCLONED_on(cv) (CvFLAGS(cv) |= CVf_CLONED) +#define CvCLONED_off(cv) (CvFLAGS(cv) &= ~CVf_CLONED) + +#define CvANON(cv) (CvFLAGS(cv) & CVf_ANON) +#define CvANON_on(cv) (CvFLAGS(cv) |= CVf_ANON) +#define CvANON_off(cv) (CvFLAGS(cv) &= ~CVf_ANON) + +#ifdef PERL_XSUB_OLDSTYLE +#define CvOLDSTYLE(cv) (CvFLAGS(cv) & CVf_OLDSTYLE) +#define CvOLDSTYLE_on(cv) (CvFLAGS(cv) |= CVf_OLDSTYLE) +#define CvOLDSTYLE_off(cv) (CvFLAGS(cv) &= ~CVf_OLDSTYLE) +#endif + +#define CvUNIQUE(cv) (CvFLAGS(cv) & CVf_UNIQUE) +#define CvUNIQUE_on(cv) (CvFLAGS(cv) |= CVf_UNIQUE) +#define CvUNIQUE_off(cv) (CvFLAGS(cv) &= ~CVf_UNIQUE) + +#define CvNODEBUG(cv) (CvFLAGS(cv) & CVf_NODEBUG) +#define CvNODEBUG_on(cv) (CvFLAGS(cv) |= CVf_NODEBUG) +#define CvNODEBUG_off(cv) (CvFLAGS(cv) &= ~CVf_NODEBUG) + +#define CvMETHOD(cv) (CvFLAGS(cv) & CVf_METHOD) +#define CvMETHOD_on(cv) (CvFLAGS(cv) |= CVf_METHOD) +#define CvMETHOD_off(cv) (CvFLAGS(cv) &= ~CVf_METHOD) + +#define CvLOCKED(cv) (CvFLAGS(cv) & CVf_LOCKED) +#define CvLOCKED_on(cv) (CvFLAGS(cv) |= CVf_LOCKED) +#define CvLOCKED_off(cv) (CvFLAGS(cv) &= ~CVf_LOCKED) + +#define CvLVALUE(cv) (CvFLAGS(cv) & CVf_LVALUE) +#define CvLVALUE_on(cv) (CvFLAGS(cv) |= CVf_LVALUE) +#define CvLVALUE_off(cv) (CvFLAGS(cv) &= ~CVf_LVALUE) + +#define CvASSERTION(cv) (CvFLAGS(cv) & CVf_ASSERTION) +#define CvASSERTION_on(cv) (CvFLAGS(cv) |= CVf_ASSERTION) +#define CvASSERTION_off(cv) (CvFLAGS(cv) &= ~CVf_ASSERTION) + +#define CvEVAL(cv) (CvUNIQUE(cv) && !SvFAKE(cv)) +#define CvEVAL_on(cv) (CvUNIQUE_on(cv),SvFAKE_off(cv)) +#define CvEVAL_off(cv) CvUNIQUE_off(cv) + +/* BEGIN|CHECK|INIT|END */ +#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) + +#define CvWEAKOUTSIDE(cv) (CvFLAGS(cv) & CVf_WEAKOUTSIDE) +#define CvWEAKOUTSIDE_on(cv) (CvFLAGS(cv) |= CVf_WEAKOUTSIDE) +#define CvWEAKOUTSIDE_off(cv) (CvFLAGS(cv) &= ~CVf_WEAKOUTSIDE) + + +/* +=head1 CV reference counts and CvOUTSIDE + +=for apidoc m|bool|CvWEAKOUTSIDE|CV *cv + +Each CV has a pointer, C, to its lexically enclosing +CV (if any). Because pointers to anonymous sub prototypes are +stored in C<&> pad slots, it is a possible to get a circular reference, +with the parent pointing to the child and vice-versa. To avoid the +ensuing memory leak, we do not increment the reference count of the CV +pointed to by C in the I that the parent +has a C<&> pad slot pointing back to us. In this case, we set the +C flag in the child. This allows us to determine under what +circumstances we should decrement the refcount of the parent when freeing +the child. + +There is a further complication with non-closure anonymous subs (ie those +that do not refer to any lexicals outside that sub). In this case, the +anonymous prototype is shared rather than being cloned. This has the +consequence that the parent may be freed while there are still active +children, eg + + BEGIN { $a = sub { eval '$x' } } + +In this case, the BEGIN is freed immediately after execution since there +are no active references to it: the anon sub prototype has +C set since it's not a closure, and $a points to the same +CV, so it doesn't contribute to BEGIN's refcount either. When $a is +executed, the C causes the chain of Cs to be followed, +and the freed BEGIN is accessed. + +To avoid this, whenever a CV and its associated pad is freed, any +C<&> entries in the pad are explicitly removed from the pad, and if the +refcount of the pointed-to anon sub is still positive, then that +child's C is set to point to its grandparent. This will only +occur in the single specific case of a non-closure anon prototype +having one or more active references (such as C<$a> above). + +One other thing to consider is that a CV may be merely undefined +rather than freed, eg C. In this case, its refcount may +not have reached zero, but we still delete its pad and its C etc. +Since various children may still have their C pointing at this +undefined CV, we keep its own C for the time being, so that +the chain of lexical scopes is unbroken. For example, the following +should print 123: + + my $x = 123; + sub tmp { sub { eval '$x' } } + my $a = tmp(); + undef &tmp; + print $a->(); +=cut +*/