[perl5.git] / cv.h

/*    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  */
#define CVf_HASEVAL	0x4000	/* contains string eval  */

/* 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)

/* CvEVAL or CvSPECIAL */
#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)

/* eval or PL_main_cv */
#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)

#define CvHASEVAL(cv)		(CvFLAGS(cv) & CVf_HASEVAL)
#define CvHASEVAL_on(cv)	(CvFLAGS(cv) |= CVf_HASEVAL)
#define CvHASEVAL_off(cv)	(CvFLAGS(cv) &= ~CVf_HASEVAL)

/* 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: nil
 * End:
 *
 * ex: set ts=8 sts=4 sw=4 et:
 */
Commit	Line	Data
a0d0e21e	1	/* cv.h
79072805	2	*
1129b882 NC	3	* Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1999, 2000, 2001,
1129b882 NC	4	* 2002, 2003, 2004, 2005, 2006, 2007, 2008 by Larry Wall and others
79072805 LW	5	*
	6	* You may distribute under the terms of either the GNU General Public
	7	* License or the Artistic License, as specified in the README file.
	8	*
79072805 LW	9	*/
79072805 LW	10
f653aab7	11	/* This structure must match the beginning of XPVFM in sv.h */
44a8e56a	12
79072805	13	struct xpvcv {
20f4945e	14	_XPV_HEAD;
20f4945e	15	_XPVCV_COMMON;
c4648999	16	I32 xcv_depth; /* >= 2 indicates recursive call */
79072805	17	};
748a9306	18
954c1994	19	/*
ccfc67b7 JH	20	=head1 Handy Values
ccfc67b7 JH	21
954c1994 GS	22	=for apidoc AmU\|\|Nullcv
	23	Null CV pointer.
	24
3ae1b226 NC	25	(deprecated - use C<(CV *)NULL> instead)
3ae1b226 NC	26
ccfc67b7 JH	27	=head1 CV Manipulation Functions
ccfc67b7 JH	28
f0b90de1 SF	29	This section documents functions to manipulate CVs which are code-values,
	30	or subroutines. For more information, see L<perlguts>.
	31
954c1994	32	=for apidoc Am\|HV\|CvSTASH\|CV cv
f0b90de1 SF	33	Returns the stash of the CV. A stash is the symbol table hash, containing
	34	the package-scoped variables in the package where the subroutine was defined.
	35	For more information, see L<perlguts>.
954c1994	36
5b36e945 FC	37	This also has a special use with XS AUTOLOAD subs.
	38	See L<perlguts/Autoloading with XSUBs>.
	39
954c1994 GS	40	=cut
	41	*/
	42
3ae1b226 NC	43	#ifndef PERL_CORE
	44	# define Nullcv Null(CV*)
	45	#endif
a5f75d66	46
c68d9564 Z	47	#define CvSTASH(sv) (0+((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_stash)
c68d9564 Z	48	#define CvSTASH_set(cv,st) Perl_cvstash_set(aTHX_ cv, st)
8f629a87 NC	49	#define CvSTART(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_start_u.xcv_start
	50	#define CvROOT(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_root_u.xcv_root
	51	#define CvXSUB(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_root_u.xcv_xsub
	52	#define CvXSUBANY(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_start_u.xcv_xsubany
b3f91e91 DM	53	#define CvGV(sv) (0+((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_gv)
b3f91e91 DM	54	#define CvGV_set(cv,gv) Perl_cvgv_set(aTHX_ cv, gv)
8f629a87	55	#define CvFILE(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_file
a636914a	56	#ifdef USE_ITHREADS
bad4ae38 FC	57	# define CvFILE_set_from_cop(sv, cop) \
bad4ae38 FC	58	(CvFILE(sv) = savepv(CopFILE(cop)), CvDYNFILE_on(sv))
a636914a	59	#else
bad4ae38 FC	60	# define CvFILE_set_from_cop(sv, cop) \
bad4ae38 FC	61	(CvFILE(sv) = CopFILE(cop), CvDYNFILE_off(sv))
a636914a	62	#endif
9ec2a764	63	#define CvFILEGV(sv) (gv_fetchfile(CvFILE(sv)))
bb172083	64	#if defined(__GNUC__) && !defined(PERL_GCC_BRACE_GROUPS_FORBIDDEN)
8f629a87	65	# define CvDEPTH(sv) (({const CV const _cvdepth = (const CV *)sv; \
5129b2ca	66	assert(SvTYPE(_cvdepth) == SVt_PVCV); \
c4648999	67	&((XPVCV*)SvANY(_cvdepth))->xcv_depth; \
bb172083 NC	68	}))
bb172083 NC	69	#else
c4648999	70	# define CvDEPTH(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_depth
bb172083	71	#endif
8f629a87 NC	72	#define CvPADLIST(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_padlist
	73	#define CvOUTSIDE(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_outside
	74	#define CvFLAGS(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_flags
	75	#define CvOUTSIDE_SEQ(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_outside_seq
a5f75d66	76
8fa6a409 FC	77	/* These two are sometimes called on non-CVs */
	78	#define CvPROTO(sv) \
	79	( \
	80	SvPOK(sv) \
	81	? SvTYPE(sv) == SVt_PVCV && CvAUTOLOAD(sv) \
	82	? SvEND(sv)+1 : SvPVX_const(sv) \
	83	: NULL \
	84	)
	85	#define CvPROTOLEN(sv) \
	86	( \
	87	SvPOK(sv) \
	88	? SvTYPE(sv) == SVt_PVCV && CvAUTOLOAD(sv) \
	89	? SvLEN(sv)-SvCUR(sv)-2 \
	90	: SvCUR(sv) \
	91	: 0 \
	92	)
	93
5b4563c8	94	#define CVf_METHOD 0x0001 /* CV is explicitly marked as a method */
c2485e0c NC	95	#define CVf_LVALUE 0x0002 /* CV return value can be used as lvalue */
	96	#define CVf_CONST 0x0004 /* inlinable sub */
	97	#define CVf_ISXSUB 0x0008 /* CV is an XSUB, not pure perl. */
5b4563c8 NC	98
	99	#define CVf_WEAKOUTSIDE 0x0010 /* CvOUTSIDE isn't ref counted */
	100	#define CVf_CLONE 0x0020 /* anon CV uses external lexicals */
	101	#define CVf_CLONED 0x0040 /* a clone of one of those */
cfc1e951	102	#define CVf_ANON 0x0080 /* CV is not pointed to by a GV */
5b4563c8	103	#define CVf_UNIQUE 0x0100 /* sub is only called once (eg PL_main_cv,
1108974d	104	* require, eval). */
5b4563c8	105	#define CVf_NODEBUG 0x0200 /* no DB::sub indirection for this CV
8ebc5c01	106	(esp. useful for special XSUBs) */
cfc1e951	107	#define CVf_CVGV_RC 0x0400 /* CvGV is reference counted */
bad4ae38	108	#define CVf_DYNFILE 0x1000 /* The filename isn't static */
8fa6a409	109	#define CVf_AUTOLOAD 0x2000 /* SvPVX contains AUTOLOADed sub name */
a0d2bbd5	110	#define CVf_HASEVAL 0x4000 /* contains string eval */
7dafbf52	111
d3cea301	112	/* This symbol for optimised communication between toke.c and op.c: */
e95ab0c0	113	#define CVf_BUILTIN_ATTRS (CVf_METHOD\|CVf_LVALUE)
a5f75d66 AD	114
	115	#define CvCLONE(cv) (CvFLAGS(cv) & CVf_CLONE)
	116	#define CvCLONE_on(cv) (CvFLAGS(cv) \|= CVf_CLONE)
	117	#define CvCLONE_off(cv) (CvFLAGS(cv) &= ~CVf_CLONE)
	118
	119	#define CvCLONED(cv) (CvFLAGS(cv) & CVf_CLONED)
	120	#define CvCLONED_on(cv) (CvFLAGS(cv) \|= CVf_CLONED)
	121	#define CvCLONED_off(cv) (CvFLAGS(cv) &= ~CVf_CLONED)
	122
	123	#define CvANON(cv) (CvFLAGS(cv) & CVf_ANON)
	124	#define CvANON_on(cv) (CvFLAGS(cv) \|= CVf_ANON)
	125	#define CvANON_off(cv) (CvFLAGS(cv) &= ~CVf_ANON)
79072805	126
a2278b6a	127	/* CvEVAL or CvSPECIAL */
07055b4c CS	128	#define CvUNIQUE(cv) (CvFLAGS(cv) & CVf_UNIQUE)
	129	#define CvUNIQUE_on(cv) (CvFLAGS(cv) \|= CVf_UNIQUE)
	130	#define CvUNIQUE_off(cv) (CvFLAGS(cv) &= ~CVf_UNIQUE)
8ebc5c01	131
	132	#define CvNODEBUG(cv) (CvFLAGS(cv) & CVf_NODEBUG)
	133	#define CvNODEBUG_on(cv) (CvFLAGS(cv) \|= CVf_NODEBUG)
	134	#define CvNODEBUG_off(cv) (CvFLAGS(cv) &= ~CVf_NODEBUG)
77a005ab MB	135
	136	#define CvMETHOD(cv) (CvFLAGS(cv) & CVf_METHOD)
	137	#define CvMETHOD_on(cv) (CvFLAGS(cv) \|= CVf_METHOD)
	138	#define CvMETHOD_off(cv) (CvFLAGS(cv) &= ~CVf_METHOD)
	139
cd06dffe GS	140	#define CvLVALUE(cv) (CvFLAGS(cv) & CVf_LVALUE)
	141	#define CvLVALUE_on(cv) (CvFLAGS(cv) \|= CVf_LVALUE)
	142	#define CvLVALUE_off(cv) (CvFLAGS(cv) &= ~CVf_LVALUE)
	143
a2278b6a	144	/* eval or PL_main_cv */
1aff0e91 GS	145	#define CvEVAL(cv) (CvUNIQUE(cv) && !SvFAKE(cv))
	146	#define CvEVAL_on(cv) (CvUNIQUE_on(cv),SvFAKE_off(cv))
	147	#define CvEVAL_off(cv) CvUNIQUE_off(cv)
	148
3c10abe3	149	/* BEGIN\|CHECK\|INIT\|UNITCHECK\|END */
1aff0e91 GS	150	#define CvSPECIAL(cv) (CvUNIQUE(cv) && SvFAKE(cv))
	151	#define CvSPECIAL_on(cv) (CvUNIQUE_on(cv),SvFAKE_on(cv))
	152	#define CvSPECIAL_off(cv) (CvUNIQUE_off(cv),SvFAKE_off(cv))
beab0874 JT	153
	154	#define CvCONST(cv) (CvFLAGS(cv) & CVf_CONST)
	155	#define CvCONST_on(cv) (CvFLAGS(cv) \|= CVf_CONST)
	156	#define CvCONST_off(cv) (CvFLAGS(cv) &= ~CVf_CONST)
a4f1a029	157
7dafbf52 DM	158	#define CvWEAKOUTSIDE(cv) (CvFLAGS(cv) & CVf_WEAKOUTSIDE)
	159	#define CvWEAKOUTSIDE_on(cv) (CvFLAGS(cv) \|= CVf_WEAKOUTSIDE)
	160	#define CvWEAKOUTSIDE_off(cv) (CvFLAGS(cv) &= ~CVf_WEAKOUTSIDE)
	161
d04ba589 NC	162	#define CvISXSUB(cv) (CvFLAGS(cv) & CVf_ISXSUB)
	163	#define CvISXSUB_on(cv) (CvFLAGS(cv) \|= CVf_ISXSUB)
	164	#define CvISXSUB_off(cv) (CvFLAGS(cv) &= ~CVf_ISXSUB)
	165
cfc1e951 DM	166	#define CvCVGV_RC(cv) (CvFLAGS(cv) & CVf_CVGV_RC)
	167	#define CvCVGV_RC_on(cv) (CvFLAGS(cv) \|= CVf_CVGV_RC)
	168	#define CvCVGV_RC_off(cv) (CvFLAGS(cv) &= ~CVf_CVGV_RC)
	169
bad4ae38 FC	170	#define CvDYNFILE(cv) (CvFLAGS(cv) & CVf_DYNFILE)
	171	#define CvDYNFILE_on(cv) (CvFLAGS(cv) \|= CVf_DYNFILE)
	172	#define CvDYNFILE_off(cv) (CvFLAGS(cv) &= ~CVf_DYNFILE)
	173
8fa6a409 FC	174	#define CvAUTOLOAD(cv) (CvFLAGS(cv) & CVf_AUTOLOAD)
	175	#define CvAUTOLOAD_on(cv) (CvFLAGS(cv) \|= CVf_AUTOLOAD)
	176	#define CvAUTOLOAD_off(cv) (CvFLAGS(cv) &= ~CVf_AUTOLOAD)
	177
a0d2bbd5 FC	178	#define CvHASEVAL(cv) (CvFLAGS(cv) & CVf_HASEVAL)
	179	#define CvHASEVAL_on(cv) (CvFLAGS(cv) \|= CVf_HASEVAL)
	180	#define CvHASEVAL_off(cv) (CvFLAGS(cv) &= ~CVf_HASEVAL)
	181
77004dee NC	182	/* Flags for newXS_flags */
	183	#define XS_DYNAMIC_FILENAME 0x01 /* The filename isn't static */
	184
7dafbf52 DM	185	/*
	186	=head1 CV reference counts and CvOUTSIDE
	187
	188	=for apidoc m\|bool\|CvWEAKOUTSIDE\|CV *cv
	189
	190	Each CV has a pointer, C<CvOUTSIDE()>, to its lexically enclosing
	191	CV (if any). Because pointers to anonymous sub prototypes are
	192	stored in C<&> pad slots, it is a possible to get a circular reference,
	193	with the parent pointing to the child and vice-versa. To avoid the
	194	ensuing memory leak, we do not increment the reference count of the CV
	195	pointed to by C<CvOUTSIDE> in the I<one specific instance> that the parent
	196	has a C<&> pad slot pointing back to us. In this case, we set the
	197	C<CvWEAKOUTSIDE> flag in the child. This allows us to determine under what
	198	circumstances we should decrement the refcount of the parent when freeing
	199	the child.
	200
eeb8d49e	201	There is a further complication with non-closure anonymous subs (i.e. those
7dafbf52 DM	202	that do not refer to any lexicals outside that sub). In this case, the
	203	anonymous prototype is shared rather than being cloned. This has the
	204	consequence that the parent may be freed while there are still active
	205	children, eg
	206
	207	BEGIN { $a = sub { eval '$x' } }
	208
	209	In this case, the BEGIN is freed immediately after execution since there
	210	are no active references to it: the anon sub prototype has
	211	C<CvWEAKOUTSIDE> set since it's not a closure, and $a points to the same
	212	CV, so it doesn't contribute to BEGIN's refcount either. When $a is
	213	executed, the C<eval '$x'> causes the chain of C<CvOUTSIDE>s to be followed,
	214	and the freed BEGIN is accessed.
	215
	216	To avoid this, whenever a CV and its associated pad is freed, any
	217	C<&> entries in the pad are explicitly removed from the pad, and if the
	218	refcount of the pointed-to anon sub is still positive, then that
	219	child's C<CvOUTSIDE> is set to point to its grandparent. This will only
	220	occur in the single specific case of a non-closure anon prototype
	221	having one or more active references (such as C<$a> above).
	222
	223	One other thing to consider is that a CV may be merely undefined
	224	rather than freed, eg C<undef &foo>. In this case, its refcount may
	225	not have reached zero, but we still delete its pad and its C<CvROOT> etc.
	226	Since various children may still have their C<CvOUTSIDE> pointing at this
	227	undefined CV, we keep its own C<CvOUTSIDE> for the time being, so that
	228	the chain of lexical scopes is unbroken. For example, the following
	229	should print 123:
	230
	231	my $x = 123;
	232	sub tmp { sub { eval '$x' } }
	233	my $a = tmp();
	234	undef &tmp;
	235	print $a->();
	236
	237	=cut
	238	*/
102d3b8a	239
d9088386 Z	240	typedef OP (Perl_call_checker)(pTHX_ OP , GV , SV *);
d9088386 Z	241
102d3b8a NC	242	/*
	243	* Local variables:
	244	* c-indentation-style: bsd
	245	* c-basic-offset: 4
14d04a33	246	* indent-tabs-mode: nil
102d3b8a NC	247	* End:
102d3b8a NC	248	*
14d04a33	249	* ex: set ts=8 sts=4 sw=4 et:
102d3b8a	250	*/