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For lexical subs, reify CvGV from CvSTASH and CvNAME_HEK
[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
ae77754a 52#define CvGV(sv) S_CvGV(aTHX_ (CV *)(sv))
b3f91e91 53#define CvGV_set(cv,gv) Perl_cvgv_set(aTHX_ cv, gv)
ae77754a 54#define CvHASGV(cv) cBOOL(SvANY(cv)->xcv_gv_u.xcv_gv)
8f629a87 55#define CvFILE(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_file
a636914a 56#ifdef USE_ITHREADS
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57# define CvFILE_set_from_cop(sv, cop) \
58 (CvFILE(sv) = savepv(CopFILE(cop)), CvDYNFILE_on(sv))
a636914a 59#else
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60# define CvFILE_set_from_cop(sv, cop) \
61 (CvFILE(sv) = CopFILE(cop), CvDYNFILE_off(sv))
a636914a 62#endif
9ec2a764 63#define CvFILEGV(sv) (gv_fetchfile(CvFILE(sv)))
1afe1db1 64#define CvDEPTH(sv) (*S_CvDEPTHp((const CV *)sv))
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65#define CvPADLIST(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_padlist
66#define CvOUTSIDE(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_outside
67#define CvFLAGS(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_flags
68#define CvOUTSIDE_SEQ(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_outside_seq
a5f75d66 69
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70/* These two are sometimes called on non-CVs */
71#define CvPROTO(sv) \
72 ( \
73 SvPOK(sv) \
74 ? SvTYPE(sv) == SVt_PVCV && CvAUTOLOAD(sv) \
75 ? SvEND(sv)+1 : SvPVX_const(sv) \
76 : NULL \
77 )
78#define CvPROTOLEN(sv) \
79 ( \
80 SvPOK(sv) \
81 ? SvTYPE(sv) == SVt_PVCV && CvAUTOLOAD(sv) \
82 ? SvLEN(sv)-SvCUR(sv)-2 \
83 : SvCUR(sv) \
84 : 0 \
85 )
86
5b4563c8 87#define CVf_METHOD 0x0001 /* CV is explicitly marked as a method */
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88#define CVf_LVALUE 0x0002 /* CV return value can be used as lvalue */
89#define CVf_CONST 0x0004 /* inlinable sub */
90#define CVf_ISXSUB 0x0008 /* CV is an XSUB, not pure perl. */
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91
92#define CVf_WEAKOUTSIDE 0x0010 /* CvOUTSIDE isn't ref counted */
93#define CVf_CLONE 0x0020 /* anon CV uses external lexicals */
94#define CVf_CLONED 0x0040 /* a clone of one of those */
cfc1e951 95#define CVf_ANON 0x0080 /* CV is not pointed to by a GV */
5b4563c8 96#define CVf_UNIQUE 0x0100 /* sub is only called once (eg PL_main_cv,
1108974d 97 * require, eval). */
5b4563c8 98#define CVf_NODEBUG 0x0200 /* no DB::sub indirection for this CV
8ebc5c01 99 (esp. useful for special XSUBs) */
cfc1e951 100#define CVf_CVGV_RC 0x0400 /* CvGV is reference counted */
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101#ifdef PERL_CORE
102# define CVf_SLABBED 0x0800 /* Holds refcount on op slab */
103#endif
bad4ae38 104#define CVf_DYNFILE 0x1000 /* The filename isn't static */
8fa6a409 105#define CVf_AUTOLOAD 0x2000 /* SvPVX contains AUTOLOADed sub name */
a0d2bbd5 106#define CVf_HASEVAL 0x4000 /* contains string eval */
b290562e 107#define CVf_NAMED 0x8000 /* Has a name HEK */
5bb151a5 108#define CVf_LEXICAL 0x10000 /* Omit package from name */
7dafbf52 109
d3cea301 110/* This symbol for optimised communication between toke.c and op.c: */
e95ab0c0 111#define CVf_BUILTIN_ATTRS (CVf_METHOD|CVf_LVALUE)
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112
113#define CvCLONE(cv) (CvFLAGS(cv) & CVf_CLONE)
114#define CvCLONE_on(cv) (CvFLAGS(cv) |= CVf_CLONE)
115#define CvCLONE_off(cv) (CvFLAGS(cv) &= ~CVf_CLONE)
116
117#define CvCLONED(cv) (CvFLAGS(cv) & CVf_CLONED)
118#define CvCLONED_on(cv) (CvFLAGS(cv) |= CVf_CLONED)
119#define CvCLONED_off(cv) (CvFLAGS(cv) &= ~CVf_CLONED)
120
121#define CvANON(cv) (CvFLAGS(cv) & CVf_ANON)
122#define CvANON_on(cv) (CvFLAGS(cv) |= CVf_ANON)
123#define CvANON_off(cv) (CvFLAGS(cv) &= ~CVf_ANON)
79072805 124
a2278b6a 125/* CvEVAL or CvSPECIAL */
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126#define CvUNIQUE(cv) (CvFLAGS(cv) & CVf_UNIQUE)
127#define CvUNIQUE_on(cv) (CvFLAGS(cv) |= CVf_UNIQUE)
128#define CvUNIQUE_off(cv) (CvFLAGS(cv) &= ~CVf_UNIQUE)
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129
130#define CvNODEBUG(cv) (CvFLAGS(cv) & CVf_NODEBUG)
131#define CvNODEBUG_on(cv) (CvFLAGS(cv) |= CVf_NODEBUG)
132#define CvNODEBUG_off(cv) (CvFLAGS(cv) &= ~CVf_NODEBUG)
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133
134#define CvMETHOD(cv) (CvFLAGS(cv) & CVf_METHOD)
135#define CvMETHOD_on(cv) (CvFLAGS(cv) |= CVf_METHOD)
136#define CvMETHOD_off(cv) (CvFLAGS(cv) &= ~CVf_METHOD)
137
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138#define CvLVALUE(cv) (CvFLAGS(cv) & CVf_LVALUE)
139#define CvLVALUE_on(cv) (CvFLAGS(cv) |= CVf_LVALUE)
140#define CvLVALUE_off(cv) (CvFLAGS(cv) &= ~CVf_LVALUE)
141
a2278b6a 142/* eval or PL_main_cv */
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143#define CvEVAL(cv) (CvUNIQUE(cv) && !SvFAKE(cv))
144#define CvEVAL_on(cv) (CvUNIQUE_on(cv),SvFAKE_off(cv))
145#define CvEVAL_off(cv) CvUNIQUE_off(cv)
146
3c10abe3 147/* BEGIN|CHECK|INIT|UNITCHECK|END */
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148#define CvSPECIAL(cv) (CvUNIQUE(cv) && SvFAKE(cv))
149#define CvSPECIAL_on(cv) (CvUNIQUE_on(cv),SvFAKE_on(cv))
150#define CvSPECIAL_off(cv) (CvUNIQUE_off(cv),SvFAKE_off(cv))
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151
152#define CvCONST(cv) (CvFLAGS(cv) & CVf_CONST)
153#define CvCONST_on(cv) (CvFLAGS(cv) |= CVf_CONST)
154#define CvCONST_off(cv) (CvFLAGS(cv) &= ~CVf_CONST)
a4f1a029 155
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156#define CvWEAKOUTSIDE(cv) (CvFLAGS(cv) & CVf_WEAKOUTSIDE)
157#define CvWEAKOUTSIDE_on(cv) (CvFLAGS(cv) |= CVf_WEAKOUTSIDE)
158#define CvWEAKOUTSIDE_off(cv) (CvFLAGS(cv) &= ~CVf_WEAKOUTSIDE)
159
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160#define CvISXSUB(cv) (CvFLAGS(cv) & CVf_ISXSUB)
161#define CvISXSUB_on(cv) (CvFLAGS(cv) |= CVf_ISXSUB)
162#define CvISXSUB_off(cv) (CvFLAGS(cv) &= ~CVf_ISXSUB)
163
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164#define CvCVGV_RC(cv) (CvFLAGS(cv) & CVf_CVGV_RC)
165#define CvCVGV_RC_on(cv) (CvFLAGS(cv) |= CVf_CVGV_RC)
166#define CvCVGV_RC_off(cv) (CvFLAGS(cv) &= ~CVf_CVGV_RC)
167
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168#ifdef PERL_CORE
169# define CvSLABBED(cv) (CvFLAGS(cv) & CVf_SLABBED)
170# define CvSLABBED_on(cv) (CvFLAGS(cv) |= CVf_SLABBED)
171# define CvSLABBED_off(cv) (CvFLAGS(cv) &= ~CVf_SLABBED)
172#endif
173
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174#define CvDYNFILE(cv) (CvFLAGS(cv) & CVf_DYNFILE)
175#define CvDYNFILE_on(cv) (CvFLAGS(cv) |= CVf_DYNFILE)
176#define CvDYNFILE_off(cv) (CvFLAGS(cv) &= ~CVf_DYNFILE)
177
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178#define CvAUTOLOAD(cv) (CvFLAGS(cv) & CVf_AUTOLOAD)
179#define CvAUTOLOAD_on(cv) (CvFLAGS(cv) |= CVf_AUTOLOAD)
180#define CvAUTOLOAD_off(cv) (CvFLAGS(cv) &= ~CVf_AUTOLOAD)
181
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182#define CvHASEVAL(cv) (CvFLAGS(cv) & CVf_HASEVAL)
183#define CvHASEVAL_on(cv) (CvFLAGS(cv) |= CVf_HASEVAL)
184#define CvHASEVAL_off(cv) (CvFLAGS(cv) &= ~CVf_HASEVAL)
185
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186#define CvNAMED(cv) (CvFLAGS(cv) & CVf_NAMED)
187#define CvNAMED_on(cv) (CvFLAGS(cv) |= CVf_NAMED)
188#define CvNAMED_off(cv) (CvFLAGS(cv) &= ~CVf_NAMED)
189
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190#define CvLEXICAL(cv) (CvFLAGS(cv) & CVf_LEXICAL)
191#define CvLEXICAL_on(cv) (CvFLAGS(cv) |= CVf_LEXICAL)
192#define CvLEXICAL_off(cv) (CvFLAGS(cv) &= ~CVf_LEXICAL)
193
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194/* Flags for newXS_flags */
195#define XS_DYNAMIC_FILENAME 0x01 /* The filename isn't static */
196
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197PERL_STATIC_INLINE HEK *
198CvNAME_HEK(CV *sv)
199{
200 return CvNAMED(sv)
201 ? ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_gv_u.xcv_hek
202 : 0;
203}
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204/* This lowers the refernce count of the previous value, but does *not*
205 increment the reference count of the new value. */
206#define CvNAME_HEK_set(cv, hek) ( \
207 CvNAME_HEK((CV *)(cv)) \
208 ? unshare_hek(SvANY((CV *)(cv))->xcv_gv_u.xcv_hek) \
209 : (void)0, \
210 ((XPVCV*)MUTABLE_PTR(SvANY(cv)))->xcv_gv_u.xcv_hek = (hek), \
211 CvNAMED_on(cv) \
212 )
b290562e 213
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214/*
215=head1 CV reference counts and CvOUTSIDE
216
217=for apidoc m|bool|CvWEAKOUTSIDE|CV *cv
218
219Each CV has a pointer, C<CvOUTSIDE()>, to its lexically enclosing
154e47c8 220CV (if any). Because pointers to anonymous sub prototypes are
7dafbf52 221stored in C<&> pad slots, it is a possible to get a circular reference,
154e47c8 222with the parent pointing to the child and vice-versa. To avoid the
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223ensuing memory leak, we do not increment the reference count of the CV
224pointed to by C<CvOUTSIDE> in the I<one specific instance> that the parent
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225has a C<&> pad slot pointing back to us. In this case, we set the
226C<CvWEAKOUTSIDE> flag in the child. This allows us to determine under what
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227circumstances we should decrement the refcount of the parent when freeing
228the child.
229
eeb8d49e 230There is a further complication with non-closure anonymous subs (i.e. those
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231that do not refer to any lexicals outside that sub). In this case, the
232anonymous prototype is shared rather than being cloned. This has the
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233consequence that the parent may be freed while there are still active
234children, eg
235
236 BEGIN { $a = sub { eval '$x' } }
237
238In this case, the BEGIN is freed immediately after execution since there
239are no active references to it: the anon sub prototype has
240C<CvWEAKOUTSIDE> set since it's not a closure, and $a points to the same
241CV, so it doesn't contribute to BEGIN's refcount either. When $a is
242executed, the C<eval '$x'> causes the chain of C<CvOUTSIDE>s to be followed,
243and the freed BEGIN is accessed.
244
245To avoid this, whenever a CV and its associated pad is freed, any
246C<&> entries in the pad are explicitly removed from the pad, and if the
247refcount of the pointed-to anon sub is still positive, then that
154e47c8 248child's C<CvOUTSIDE> is set to point to its grandparent. This will only
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249occur in the single specific case of a non-closure anon prototype
250having one or more active references (such as C<$a> above).
251
252One other thing to consider is that a CV may be merely undefined
154e47c8 253rather than freed, eg C<undef &foo>. In this case, its refcount may
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254not have reached zero, but we still delete its pad and its C<CvROOT> etc.
255Since various children may still have their C<CvOUTSIDE> pointing at this
256undefined CV, we keep its own C<CvOUTSIDE> for the time being, so that
154e47c8 257the chain of lexical scopes is unbroken. For example, the following
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258should print 123:
259
260 my $x = 123;
261 sub tmp { sub { eval '$x' } }
262 my $a = tmp();
263 undef &tmp;
264 print $a->();
265
266=cut
267*/
102d3b8a 268
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269typedef OP *(*Perl_call_checker)(pTHX_ OP *, GV *, SV *);
270
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271/*
272 * Local variables:
273 * c-indentation-style: bsd
274 * c-basic-offset: 4
14d04a33 275 * indent-tabs-mode: nil
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276 * End:
277 *
14d04a33 278 * ex: set ts=8 sts=4 sw=4 et:
102d3b8a 279 */