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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;
c4648999 16 I32 xcv_depth; /* >= 2 indicates recursive call */
79072805 17};
748a9306 18
954c1994 19/*
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20=head1 Handy Values
21
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22=for apidoc AmU||Nullcv
23Null CV pointer.
24
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25(deprecated - use C<(CV *)NULL> instead)
26
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27=head1 CV Manipulation Functions
28
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29This section documents functions to manipulate CVs which are code-values,
30or subroutines. For more information, see L<perlguts>.
31
954c1994 32=for apidoc Am|HV*|CvSTASH|CV* cv
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33Returns the stash of the CV. A stash is the symbol table hash, containing
34the package-scoped variables in the package where the subroutine was defined.
35For more information, see L<perlguts>.
954c1994 36
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37This also has a special use with XS AUTOLOAD subs.
38See L<perlguts/Autoloading with XSUBs>.
39
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40=cut
41*/
42
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43#ifndef PERL_CORE
44# define Nullcv Null(CV*)
45#endif
a5f75d66 46
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47#define CvSTASH(sv) (0+((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_stash)
48#define CvSTASH_set(cv,st) Perl_cvstash_set(aTHX_ cv, st)
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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
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53#define CvGV(sv) (0+((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_gv)
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
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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)))
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; \
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68 }))
69#else
c4648999 70# define CvDEPTH(sv) ((XPVCV*)MUTABLE_PTR(SvANY(sv)))->xcv_depth
bb172083 71#endif
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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
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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 */
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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. */
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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 */
7dafbf52 110
d3cea301 111/* This symbol for optimised communication between toke.c and op.c: */
e95ab0c0 112#define CVf_BUILTIN_ATTRS (CVf_METHOD|CVf_LVALUE)
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113
114#define CvCLONE(cv) (CvFLAGS(cv) & CVf_CLONE)
115#define CvCLONE_on(cv) (CvFLAGS(cv) |= CVf_CLONE)
116#define CvCLONE_off(cv) (CvFLAGS(cv) &= ~CVf_CLONE)
117
118#define CvCLONED(cv) (CvFLAGS(cv) & CVf_CLONED)
119#define CvCLONED_on(cv) (CvFLAGS(cv) |= CVf_CLONED)
120#define CvCLONED_off(cv) (CvFLAGS(cv) &= ~CVf_CLONED)
121
122#define CvANON(cv) (CvFLAGS(cv) & CVf_ANON)
123#define CvANON_on(cv) (CvFLAGS(cv) |= CVf_ANON)
124#define CvANON_off(cv) (CvFLAGS(cv) &= ~CVf_ANON)
79072805 125
a2278b6a 126/* CvEVAL or CvSPECIAL */
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127#define CvUNIQUE(cv) (CvFLAGS(cv) & CVf_UNIQUE)
128#define CvUNIQUE_on(cv) (CvFLAGS(cv) |= CVf_UNIQUE)
129#define CvUNIQUE_off(cv) (CvFLAGS(cv) &= ~CVf_UNIQUE)
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130
131#define CvNODEBUG(cv) (CvFLAGS(cv) & CVf_NODEBUG)
132#define CvNODEBUG_on(cv) (CvFLAGS(cv) |= CVf_NODEBUG)
133#define CvNODEBUG_off(cv) (CvFLAGS(cv) &= ~CVf_NODEBUG)
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134
135#define CvMETHOD(cv) (CvFLAGS(cv) & CVf_METHOD)
136#define CvMETHOD_on(cv) (CvFLAGS(cv) |= CVf_METHOD)
137#define CvMETHOD_off(cv) (CvFLAGS(cv) &= ~CVf_METHOD)
138
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139#define CvLVALUE(cv) (CvFLAGS(cv) & CVf_LVALUE)
140#define CvLVALUE_on(cv) (CvFLAGS(cv) |= CVf_LVALUE)
141#define CvLVALUE_off(cv) (CvFLAGS(cv) &= ~CVf_LVALUE)
142
a2278b6a 143/* eval or PL_main_cv */
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144#define CvEVAL(cv) (CvUNIQUE(cv) && !SvFAKE(cv))
145#define CvEVAL_on(cv) (CvUNIQUE_on(cv),SvFAKE_off(cv))
146#define CvEVAL_off(cv) CvUNIQUE_off(cv)
147
3c10abe3 148/* BEGIN|CHECK|INIT|UNITCHECK|END */
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149#define CvSPECIAL(cv) (CvUNIQUE(cv) && SvFAKE(cv))
150#define CvSPECIAL_on(cv) (CvUNIQUE_on(cv),SvFAKE_on(cv))
151#define CvSPECIAL_off(cv) (CvUNIQUE_off(cv),SvFAKE_off(cv))
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152
153#define CvCONST(cv) (CvFLAGS(cv) & CVf_CONST)
154#define CvCONST_on(cv) (CvFLAGS(cv) |= CVf_CONST)
155#define CvCONST_off(cv) (CvFLAGS(cv) &= ~CVf_CONST)
a4f1a029 156
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157#define CvWEAKOUTSIDE(cv) (CvFLAGS(cv) & CVf_WEAKOUTSIDE)
158#define CvWEAKOUTSIDE_on(cv) (CvFLAGS(cv) |= CVf_WEAKOUTSIDE)
159#define CvWEAKOUTSIDE_off(cv) (CvFLAGS(cv) &= ~CVf_WEAKOUTSIDE)
160
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161#define CvISXSUB(cv) (CvFLAGS(cv) & CVf_ISXSUB)
162#define CvISXSUB_on(cv) (CvFLAGS(cv) |= CVf_ISXSUB)
163#define CvISXSUB_off(cv) (CvFLAGS(cv) &= ~CVf_ISXSUB)
164
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165#define CvCVGV_RC(cv) (CvFLAGS(cv) & CVf_CVGV_RC)
166#define CvCVGV_RC_on(cv) (CvFLAGS(cv) |= CVf_CVGV_RC)
167#define CvCVGV_RC_off(cv) (CvFLAGS(cv) &= ~CVf_CVGV_RC)
168
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169#define CvDYNFILE(cv) (CvFLAGS(cv) & CVf_DYNFILE)
170#define CvDYNFILE_on(cv) (CvFLAGS(cv) |= CVf_DYNFILE)
171#define CvDYNFILE_off(cv) (CvFLAGS(cv) &= ~CVf_DYNFILE)
172
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173#define CvAUTOLOAD(cv) (CvFLAGS(cv) & CVf_AUTOLOAD)
174#define CvAUTOLOAD_on(cv) (CvFLAGS(cv) |= CVf_AUTOLOAD)
175#define CvAUTOLOAD_off(cv) (CvFLAGS(cv) &= ~CVf_AUTOLOAD)
176
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177/* Flags for newXS_flags */
178#define XS_DYNAMIC_FILENAME 0x01 /* The filename isn't static */
179
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180/*
181=head1 CV reference counts and CvOUTSIDE
182
183=for apidoc m|bool|CvWEAKOUTSIDE|CV *cv
184
185Each CV has a pointer, C<CvOUTSIDE()>, to its lexically enclosing
186CV (if any). Because pointers to anonymous sub prototypes are
187stored in C<&> pad slots, it is a possible to get a circular reference,
188with the parent pointing to the child and vice-versa. To avoid the
189ensuing memory leak, we do not increment the reference count of the CV
190pointed to by C<CvOUTSIDE> in the I<one specific instance> that the parent
191has a C<&> pad slot pointing back to us. In this case, we set the
192C<CvWEAKOUTSIDE> flag in the child. This allows us to determine under what
193circumstances we should decrement the refcount of the parent when freeing
194the child.
195
eeb8d49e 196There is a further complication with non-closure anonymous subs (i.e. those
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197that do not refer to any lexicals outside that sub). In this case, the
198anonymous prototype is shared rather than being cloned. This has the
199consequence that the parent may be freed while there are still active
200children, eg
201
202 BEGIN { $a = sub { eval '$x' } }
203
204In this case, the BEGIN is freed immediately after execution since there
205are no active references to it: the anon sub prototype has
206C<CvWEAKOUTSIDE> set since it's not a closure, and $a points to the same
207CV, so it doesn't contribute to BEGIN's refcount either. When $a is
208executed, the C<eval '$x'> causes the chain of C<CvOUTSIDE>s to be followed,
209and the freed BEGIN is accessed.
210
211To avoid this, whenever a CV and its associated pad is freed, any
212C<&> entries in the pad are explicitly removed from the pad, and if the
213refcount of the pointed-to anon sub is still positive, then that
214child's C<CvOUTSIDE> is set to point to its grandparent. This will only
215occur in the single specific case of a non-closure anon prototype
216having one or more active references (such as C<$a> above).
217
218One other thing to consider is that a CV may be merely undefined
219rather than freed, eg C<undef &foo>. In this case, its refcount may
220not have reached zero, but we still delete its pad and its C<CvROOT> etc.
221Since various children may still have their C<CvOUTSIDE> pointing at this
222undefined CV, we keep its own C<CvOUTSIDE> for the time being, so that
223the chain of lexical scopes is unbroken. For example, the following
224should print 123:
225
226 my $x = 123;
227 sub tmp { sub { eval '$x' } }
228 my $a = tmp();
229 undef &tmp;
230 print $a->();
231
232=cut
233*/
102d3b8a 234
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235typedef OP *(*Perl_call_checker)(pTHX_ OP *, GV *, SV *);
236
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237/*
238 * Local variables:
239 * c-indentation-style: bsd
240 * c-basic-offset: 4
14d04a33 241 * indent-tabs-mode: nil
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242 * End:
243 *
14d04a33 244 * ex: set ts=8 sts=4 sw=4 et:
102d3b8a 245 */