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Add CVf_LEXICAL flag
[perl5.git] / cv.h
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a0d0e21e 1/* cv.h
79072805 2 *
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3 * Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1999, 2000, 2001,
4 * 2002, 2003, 2004, 2005, 2006, 2007, 2008 by Larry Wall and others
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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 *
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9 */
10
f653aab7 11/* This structure must match the beginning of XPVFM in sv.h */
44a8e56a 12
79072805 13struct xpvcv {
20f4945e 14 _XPV_HEAD;
20f4945e 15 _XPVCV_COMMON;
79072805 16};
748a9306 17
954c1994 18/*
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19=head1 Handy Values
20
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21=for apidoc AmU||Nullcv
22Null CV pointer.
23
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24(deprecated - use C<(CV *)NULL> instead)
25
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26=head1 CV Manipulation Functions
27
f0b90de1 28This section documents functions to manipulate CVs which are code-values,
154e47c8 29or subroutines. For more information, see L<perlguts>.
f0b90de1 30
954c1994 31=for apidoc Am|HV*|CvSTASH|CV* cv
72d33970 32Returns the stash of the CV. A stash is the symbol table hash, containing
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33the package-scoped variables in the package where the subroutine was defined.
34For more information, see L<perlguts>.
954c1994 35
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36This also has a special use with XS AUTOLOAD subs.
37See L<perlguts/Autoloading with XSUBs>.
38
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39=cut
40*/
41
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42#ifndef PERL_CORE
43# define Nullcv Null(CV*)
44#endif
a5f75d66 45
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46#define CvSTASH(sv) (0+((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_stash)
47#define CvSTASH_set(cv,st) Perl_cvstash_set(aTHX_ cv, st)
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48#define CvSTART(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_start_u.xcv_start
49#define CvROOT(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_root_u.xcv_root
50#define CvXSUB(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_root_u.xcv_xsub
51#define CvXSUBANY(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_start_u.xcv_xsubany
bca8f980 52#define CvGV(sv) S_CvGV((const CV *)(sv))
b3f91e91 53#define CvGV_set(cv,gv) Perl_cvgv_set(aTHX_ cv, gv)
8f629a87 54#define CvFILE(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_file
a636914a 55#ifdef USE_ITHREADS
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56# define CvFILE_set_from_cop(sv, cop) \
57 (CvFILE(sv) = savepv(CopFILE(cop)), CvDYNFILE_on(sv))
a636914a 58#else
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59# define CvFILE_set_from_cop(sv, cop) \
60 (CvFILE(sv) = CopFILE(cop), CvDYNFILE_off(sv))
a636914a 61#endif
9ec2a764 62#define CvFILEGV(sv) (gv_fetchfile(CvFILE(sv)))
1afe1db1 63#define CvDEPTH(sv) (*S_CvDEPTHp((const CV *)sv))
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64#define CvPADLIST(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_padlist
65#define CvOUTSIDE(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_outside
66#define CvFLAGS(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_flags
67#define CvOUTSIDE_SEQ(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_outside_seq
a5f75d66 68
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69/* These two are sometimes called on non-CVs */
70#define CvPROTO(sv) \
71 ( \
72 SvPOK(sv) \
73 ? SvTYPE(sv) == SVt_PVCV && CvAUTOLOAD(sv) \
74 ? SvEND(sv)+1 : SvPVX_const(sv) \
75 : NULL \
76 )
77#define CvPROTOLEN(sv) \
78 ( \
79 SvPOK(sv) \
80 ? SvTYPE(sv) == SVt_PVCV && CvAUTOLOAD(sv) \
81 ? SvLEN(sv)-SvCUR(sv)-2 \
82 : SvCUR(sv) \
83 : 0 \
84 )
85
5b4563c8 86#define CVf_METHOD 0x0001 /* CV is explicitly marked as a method */
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87#define CVf_LVALUE 0x0002 /* CV return value can be used as lvalue */
88#define CVf_CONST 0x0004 /* inlinable sub */
89#define CVf_ISXSUB 0x0008 /* CV is an XSUB, not pure perl. */
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90
91#define CVf_WEAKOUTSIDE 0x0010 /* CvOUTSIDE isn't ref counted */
92#define CVf_CLONE 0x0020 /* anon CV uses external lexicals */
93#define CVf_CLONED 0x0040 /* a clone of one of those */
cfc1e951 94#define CVf_ANON 0x0080 /* CV is not pointed to by a GV */
5b4563c8 95#define CVf_UNIQUE 0x0100 /* sub is only called once (eg PL_main_cv,
1108974d 96 * require, eval). */
5b4563c8 97#define CVf_NODEBUG 0x0200 /* no DB::sub indirection for this CV
8ebc5c01 98 (esp. useful for special XSUBs) */
cfc1e951 99#define CVf_CVGV_RC 0x0400 /* CvGV is reference counted */
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100#ifdef PERL_CORE
101# define CVf_SLABBED 0x0800 /* Holds refcount on op slab */
102#endif
bad4ae38 103#define CVf_DYNFILE 0x1000 /* The filename isn't static */
8fa6a409 104#define CVf_AUTOLOAD 0x2000 /* SvPVX contains AUTOLOADed sub name */
a0d2bbd5 105#define CVf_HASEVAL 0x4000 /* contains string eval */
b290562e 106#define CVf_NAMED 0x8000 /* Has a name HEK */
5bb151a5 107#define CVf_LEXICAL 0x10000 /* Omit package from name */
7dafbf52 108
d3cea301 109/* This symbol for optimised communication between toke.c and op.c: */
e95ab0c0 110#define CVf_BUILTIN_ATTRS (CVf_METHOD|CVf_LVALUE)
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111
112#define CvCLONE(cv) (CvFLAGS(cv) & CVf_CLONE)
113#define CvCLONE_on(cv) (CvFLAGS(cv) |= CVf_CLONE)
114#define CvCLONE_off(cv) (CvFLAGS(cv) &= ~CVf_CLONE)
115
116#define CvCLONED(cv) (CvFLAGS(cv) & CVf_CLONED)
117#define CvCLONED_on(cv) (CvFLAGS(cv) |= CVf_CLONED)
118#define CvCLONED_off(cv) (CvFLAGS(cv) &= ~CVf_CLONED)
119
120#define CvANON(cv) (CvFLAGS(cv) & CVf_ANON)
121#define CvANON_on(cv) (CvFLAGS(cv) |= CVf_ANON)
122#define CvANON_off(cv) (CvFLAGS(cv) &= ~CVf_ANON)
79072805 123
a2278b6a 124/* CvEVAL or CvSPECIAL */
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125#define CvUNIQUE(cv) (CvFLAGS(cv) & CVf_UNIQUE)
126#define CvUNIQUE_on(cv) (CvFLAGS(cv) |= CVf_UNIQUE)
127#define CvUNIQUE_off(cv) (CvFLAGS(cv) &= ~CVf_UNIQUE)
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128
129#define CvNODEBUG(cv) (CvFLAGS(cv) & CVf_NODEBUG)
130#define CvNODEBUG_on(cv) (CvFLAGS(cv) |= CVf_NODEBUG)
131#define CvNODEBUG_off(cv) (CvFLAGS(cv) &= ~CVf_NODEBUG)
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132
133#define CvMETHOD(cv) (CvFLAGS(cv) & CVf_METHOD)
134#define CvMETHOD_on(cv) (CvFLAGS(cv) |= CVf_METHOD)
135#define CvMETHOD_off(cv) (CvFLAGS(cv) &= ~CVf_METHOD)
136
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137#define CvLVALUE(cv) (CvFLAGS(cv) & CVf_LVALUE)
138#define CvLVALUE_on(cv) (CvFLAGS(cv) |= CVf_LVALUE)
139#define CvLVALUE_off(cv) (CvFLAGS(cv) &= ~CVf_LVALUE)
140
a2278b6a 141/* eval or PL_main_cv */
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142#define CvEVAL(cv) (CvUNIQUE(cv) && !SvFAKE(cv))
143#define CvEVAL_on(cv) (CvUNIQUE_on(cv),SvFAKE_off(cv))
144#define CvEVAL_off(cv) CvUNIQUE_off(cv)
145
3c10abe3 146/* BEGIN|CHECK|INIT|UNITCHECK|END */
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147#define CvSPECIAL(cv) (CvUNIQUE(cv) && SvFAKE(cv))
148#define CvSPECIAL_on(cv) (CvUNIQUE_on(cv),SvFAKE_on(cv))
149#define CvSPECIAL_off(cv) (CvUNIQUE_off(cv),SvFAKE_off(cv))
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150
151#define CvCONST(cv) (CvFLAGS(cv) & CVf_CONST)
152#define CvCONST_on(cv) (CvFLAGS(cv) |= CVf_CONST)
153#define CvCONST_off(cv) (CvFLAGS(cv) &= ~CVf_CONST)
a4f1a029 154
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155#define CvWEAKOUTSIDE(cv) (CvFLAGS(cv) & CVf_WEAKOUTSIDE)
156#define CvWEAKOUTSIDE_on(cv) (CvFLAGS(cv) |= CVf_WEAKOUTSIDE)
157#define CvWEAKOUTSIDE_off(cv) (CvFLAGS(cv) &= ~CVf_WEAKOUTSIDE)
158
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159#define CvISXSUB(cv) (CvFLAGS(cv) & CVf_ISXSUB)
160#define CvISXSUB_on(cv) (CvFLAGS(cv) |= CVf_ISXSUB)
161#define CvISXSUB_off(cv) (CvFLAGS(cv) &= ~CVf_ISXSUB)
162
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163#define CvCVGV_RC(cv) (CvFLAGS(cv) & CVf_CVGV_RC)
164#define CvCVGV_RC_on(cv) (CvFLAGS(cv) |= CVf_CVGV_RC)
165#define CvCVGV_RC_off(cv) (CvFLAGS(cv) &= ~CVf_CVGV_RC)
166
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167#ifdef PERL_CORE
168# define CvSLABBED(cv) (CvFLAGS(cv) & CVf_SLABBED)
169# define CvSLABBED_on(cv) (CvFLAGS(cv) |= CVf_SLABBED)
170# define CvSLABBED_off(cv) (CvFLAGS(cv) &= ~CVf_SLABBED)
171#endif
172
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173#define CvDYNFILE(cv) (CvFLAGS(cv) & CVf_DYNFILE)
174#define CvDYNFILE_on(cv) (CvFLAGS(cv) |= CVf_DYNFILE)
175#define CvDYNFILE_off(cv) (CvFLAGS(cv) &= ~CVf_DYNFILE)
176
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177#define CvAUTOLOAD(cv) (CvFLAGS(cv) & CVf_AUTOLOAD)
178#define CvAUTOLOAD_on(cv) (CvFLAGS(cv) |= CVf_AUTOLOAD)
179#define CvAUTOLOAD_off(cv) (CvFLAGS(cv) &= ~CVf_AUTOLOAD)
180
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181#define CvHASEVAL(cv) (CvFLAGS(cv) & CVf_HASEVAL)
182#define CvHASEVAL_on(cv) (CvFLAGS(cv) |= CVf_HASEVAL)
183#define CvHASEVAL_off(cv) (CvFLAGS(cv) &= ~CVf_HASEVAL)
184
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185#define CvNAMED(cv) (CvFLAGS(cv) & CVf_NAMED)
186#define CvNAMED_on(cv) (CvFLAGS(cv) |= CVf_NAMED)
187#define CvNAMED_off(cv) (CvFLAGS(cv) &= ~CVf_NAMED)
188
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189#define CvLEXICAL(cv) (CvFLAGS(cv) & CVf_LEXICAL)
190#define CvLEXICAL_on(cv) (CvFLAGS(cv) |= CVf_LEXICAL)
191#define CvLEXICAL_off(cv) (CvFLAGS(cv) &= ~CVf_LEXICAL)
192
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193/* Flags for newXS_flags */
194#define XS_DYNAMIC_FILENAME 0x01 /* The filename isn't static */
195
b290562e 196PERL_STATIC_INLINE GV *
bca8f980 197S_CvGV(const CV *sv)
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198{
199 return CvNAMED(sv)
200 ? 0
201 : ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_gv_u.xcv_gv;
202}
203PERL_STATIC_INLINE HEK *
204CvNAME_HEK(CV *sv)
205{
206 return CvNAMED(sv)
207 ? ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_gv_u.xcv_hek
208 : 0;
209}
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210/* This lowers the refernce count of the previous value, but does *not*
211 increment the reference count of the new value. */
212#define CvNAME_HEK_set(cv, hek) ( \
213 CvNAME_HEK((CV *)(cv)) \
214 ? unshare_hek(SvANY((CV *)(cv))->xcv_gv_u.xcv_hek) \
215 : (void)0, \
216 ((XPVCV*)MUTABLE_PTR(SvANY(cv)))->xcv_gv_u.xcv_hek = (hek), \
217 CvNAMED_on(cv) \
218 )
b290562e 219
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220/*
221=head1 CV reference counts and CvOUTSIDE
222
223=for apidoc m|bool|CvWEAKOUTSIDE|CV *cv
224
225Each CV has a pointer, C<CvOUTSIDE()>, to its lexically enclosing
154e47c8 226CV (if any). Because pointers to anonymous sub prototypes are
7dafbf52 227stored in C<&> pad slots, it is a possible to get a circular reference,
154e47c8 228with the parent pointing to the child and vice-versa. To avoid the
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229ensuing memory leak, we do not increment the reference count of the CV
230pointed to by C<CvOUTSIDE> in the I<one specific instance> that the parent
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231has a C<&> pad slot pointing back to us. In this case, we set the
232C<CvWEAKOUTSIDE> flag in the child. This allows us to determine under what
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233circumstances we should decrement the refcount of the parent when freeing
234the child.
235
eeb8d49e 236There is a further complication with non-closure anonymous subs (i.e. those
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237that do not refer to any lexicals outside that sub). In this case, the
238anonymous prototype is shared rather than being cloned. This has the
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239consequence that the parent may be freed while there are still active
240children, eg
241
242 BEGIN { $a = sub { eval '$x' } }
243
244In this case, the BEGIN is freed immediately after execution since there
245are no active references to it: the anon sub prototype has
246C<CvWEAKOUTSIDE> set since it's not a closure, and $a points to the same
247CV, so it doesn't contribute to BEGIN's refcount either. When $a is
248executed, the C<eval '$x'> causes the chain of C<CvOUTSIDE>s to be followed,
249and the freed BEGIN is accessed.
250
251To avoid this, whenever a CV and its associated pad is freed, any
252C<&> entries in the pad are explicitly removed from the pad, and if the
253refcount of the pointed-to anon sub is still positive, then that
154e47c8 254child's C<CvOUTSIDE> is set to point to its grandparent. This will only
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255occur in the single specific case of a non-closure anon prototype
256having one or more active references (such as C<$a> above).
257
258One other thing to consider is that a CV may be merely undefined
154e47c8 259rather than freed, eg C<undef &foo>. In this case, its refcount may
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260not have reached zero, but we still delete its pad and its C<CvROOT> etc.
261Since various children may still have their C<CvOUTSIDE> pointing at this
262undefined CV, we keep its own C<CvOUTSIDE> for the time being, so that
154e47c8 263the chain of lexical scopes is unbroken. For example, the following
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264should print 123:
265
266 my $x = 123;
267 sub tmp { sub { eval '$x' } }
268 my $a = tmp();
269 undef &tmp;
270 print $a->();
271
272=cut
273*/
102d3b8a 274
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275typedef OP *(*Perl_call_checker)(pTHX_ OP *, GV *, SV *);
276
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277/*
278 * Local variables:
279 * c-indentation-style: bsd
280 * c-basic-offset: 4
14d04a33 281 * indent-tabs-mode: nil
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282 * End:
283 *
14d04a33 284 * ex: set ts=8 sts=4 sw=4 et:
102d3b8a 285 */