| /* cv.h |
| * |
| * Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1999, 2000, 2001, |
| * 2002, 2003, 2004, 2005, 2006, 2007, 2008 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. |
| * |
| */ |
| |
| /* This structure must match the beginning of XPVFM in sv.h */ |
| |
| struct xpvcv { |
| _XPV_HEAD; |
| _XPVCV_COMMON; |
| I32 xcv_depth; /* >= 2 indicates recursive call */ |
| }; |
| |
| /* |
| =head1 Handy Values |
| |
| =for apidoc AmU||Nullcv |
| Null CV pointer. |
| |
| (deprecated - use C<(CV *)NULL> instead) |
| |
| =head1 CV Manipulation Functions |
| |
| This section documents functions to manipulate CVs which are code-values, |
| or subroutines. For more information, see L<perlguts>. |
| |
| =for apidoc Am|HV*|CvSTASH|CV* cv |
| Returns the stash of the CV. A stash is the symbol table hash, containing |
| the package-scoped variables in the package where the subroutine was defined. |
| For more information, see L<perlguts>. |
| |
| This also has a special use with XS AUTOLOAD subs. |
| See L<perlguts/Autoloading with XSUBs>. |
| |
| =cut |
| */ |
| |
| #ifndef PERL_CORE |
| # define Nullcv Null(CV*) |
| #endif |
| |
| #define CvSTASH(sv) (0+((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_stash) |
| #define CvSTASH_set(cv,st) Perl_cvstash_set(aTHX_ cv, st) |
| #define CvSTART(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_start_u.xcv_start |
| #define CvROOT(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_root_u.xcv_root |
| #define CvXSUB(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_root_u.xcv_xsub |
| #define CvXSUBANY(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_start_u.xcv_xsubany |
| #define CvGV(sv) (0+((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_gv) |
| #define CvGV_set(cv,gv) Perl_cvgv_set(aTHX_ cv, gv) |
| #define CvFILE(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_file |
| #ifdef USE_ITHREADS |
| # define CvFILE_set_from_cop(sv, cop) \ |
| (CvFILE(sv) = savepv(CopFILE(cop)), CvDYNFILE_on(sv)) |
| #else |
| # define CvFILE_set_from_cop(sv, cop) \ |
| (CvFILE(sv) = CopFILE(cop), CvDYNFILE_off(sv)) |
| #endif |
| #define CvFILEGV(sv) (gv_fetchfile(CvFILE(sv))) |
| #if defined(__GNUC__) && !defined(PERL_GCC_BRACE_GROUPS_FORBIDDEN) |
| # define CvDEPTH(sv) (*({const CV *const _cvdepth = (const CV *)sv; \ |
| assert(SvTYPE(_cvdepth) == SVt_PVCV); \ |
| &((XPVCV*)SvANY(_cvdepth))->xcv_depth; \ |
| })) |
| #else |
| # define CvDEPTH(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_depth |
| #endif |
| #define CvPADLIST(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_padlist |
| #define CvOUTSIDE(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_outside |
| #define CvFLAGS(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_flags |
| #define CvOUTSIDE_SEQ(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_outside_seq |
| |
| /* These two are sometimes called on non-CVs */ |
| #define CvPROTO(sv) \ |
| ( \ |
| SvPOK(sv) \ |
| ? SvTYPE(sv) == SVt_PVCV && CvAUTOLOAD(sv) \ |
| ? SvEND(sv)+1 : SvPVX_const(sv) \ |
| : NULL \ |
| ) |
| #define CvPROTOLEN(sv) \ |
| ( \ |
| SvPOK(sv) \ |
| ? SvTYPE(sv) == SVt_PVCV && CvAUTOLOAD(sv) \ |
| ? SvLEN(sv)-SvCUR(sv)-2 \ |
| : SvCUR(sv) \ |
| : 0 \ |
| ) |
| |
| #define CVf_METHOD 0x0001 /* CV is explicitly marked as a method */ |
| #define CVf_LVALUE 0x0002 /* CV return value can be used as lvalue */ |
| #define CVf_CONST 0x0004 /* inlinable sub */ |
| #define CVf_ISXSUB 0x0008 /* CV is an XSUB, not pure perl. */ |
| |
| #define CVf_WEAKOUTSIDE 0x0010 /* CvOUTSIDE isn't ref counted */ |
| #define CVf_CLONE 0x0020 /* anon CV uses external lexicals */ |
| #define CVf_CLONED 0x0040 /* a clone of one of those */ |
| #define CVf_ANON 0x0080 /* CV is not pointed to by a GV */ |
| #define CVf_UNIQUE 0x0100 /* sub is only called once (eg PL_main_cv, |
| * require, eval). */ |
| #define CVf_NODEBUG 0x0200 /* no DB::sub indirection for this CV |
| (esp. useful for special XSUBs) */ |
| #define CVf_CVGV_RC 0x0400 /* CvGV is reference counted */ |
| #define CVf_DYNFILE 0x1000 /* The filename isn't static */ |
| #define CVf_AUTOLOAD 0x2000 /* SvPVX contains AUTOLOADed sub name */ |
| |
| /* This symbol for optimised communication between toke.c and op.c: */ |
| #define CVf_BUILTIN_ATTRS (CVf_METHOD|CVf_LVALUE) |
| |
| #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) |
| |
| #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 CvLVALUE(cv) (CvFLAGS(cv) & CVf_LVALUE) |
| #define CvLVALUE_on(cv) (CvFLAGS(cv) |= CVf_LVALUE) |
| #define CvLVALUE_off(cv) (CvFLAGS(cv) &= ~CVf_LVALUE) |
| |
| #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|UNITCHECK|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) |
| |
| #define CvISXSUB(cv) (CvFLAGS(cv) & CVf_ISXSUB) |
| #define CvISXSUB_on(cv) (CvFLAGS(cv) |= CVf_ISXSUB) |
| #define CvISXSUB_off(cv) (CvFLAGS(cv) &= ~CVf_ISXSUB) |
| |
| #define CvCVGV_RC(cv) (CvFLAGS(cv) & CVf_CVGV_RC) |
| #define CvCVGV_RC_on(cv) (CvFLAGS(cv) |= CVf_CVGV_RC) |
| #define CvCVGV_RC_off(cv) (CvFLAGS(cv) &= ~CVf_CVGV_RC) |
| |
| #define CvDYNFILE(cv) (CvFLAGS(cv) & CVf_DYNFILE) |
| #define CvDYNFILE_on(cv) (CvFLAGS(cv) |= CVf_DYNFILE) |
| #define CvDYNFILE_off(cv) (CvFLAGS(cv) &= ~CVf_DYNFILE) |
| |
| #define CvAUTOLOAD(cv) (CvFLAGS(cv) & CVf_AUTOLOAD) |
| #define CvAUTOLOAD_on(cv) (CvFLAGS(cv) |= CVf_AUTOLOAD) |
| #define CvAUTOLOAD_off(cv) (CvFLAGS(cv) &= ~CVf_AUTOLOAD) |
| |
| /* Flags for newXS_flags */ |
| #define XS_DYNAMIC_FILENAME 0x01 /* The filename isn't static */ |
| |
| /* |
| =head1 CV reference counts and CvOUTSIDE |
| |
| =for apidoc m|bool|CvWEAKOUTSIDE|CV *cv |
| |
| Each CV has a pointer, C<CvOUTSIDE()>, 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<CvOUTSIDE> in the I<one specific instance> that the parent |
| has a C<&> pad slot pointing back to us. In this case, we set the |
| C<CvWEAKOUTSIDE> 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 (i.e. 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<CvWEAKOUTSIDE> 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 $a is |
| executed, the C<eval '$x'> causes the chain of C<CvOUTSIDE>s 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<CvOUTSIDE> 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<undef &foo>. In this case, its refcount may |
| not have reached zero, but we still delete its pad and its C<CvROOT> etc. |
| Since various children may still have their C<CvOUTSIDE> pointing at this |
| undefined CV, we keep its own C<CvOUTSIDE> 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 |
| */ |
| |
| typedef OP *(*Perl_call_checker)(pTHX_ OP *, GV *, SV *); |
| |
| /* |
| * Local variables: |
| * c-indentation-style: bsd |
| * c-basic-offset: 4 |
| * indent-tabs-mode: t |
| * End: |
| * |
| * ex: set ts=8 sts=4 sw=4 noet: |
| */ |
