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Move the low/high cop sequences from NVX/IVX to a two U32 structure
[perl5.git] / cv.h
CommitLineData
a0d0e21e 1/* cv.h
79072805 2 *
4bb101f2 3 * Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1999,
bf53b3a5 4 * 2000, 2001, 2002, 2003, 2004, 2005, 2006, by Larry Wall and others
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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 *
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9 */
10
7c60e434 11/* This structure must the beginning of XPVFM in sv.h */
44a8e56a 12
79072805 13struct xpvcv {
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14 union {
15 NV xnv_nv; /* numeric value, if any */
16 HV * xgv_stash;
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17 struct {
18 U32 xlow;
19 U32 xhigh;
20 } xpad_cop_seq; /* used by pad.c for cop_sequence */
58430790 21 } xnv_u;
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22 STRLEN xpv_cur; /* length of xp_pv as a C string */
23 STRLEN xpv_len; /* allocated size */
e4305a63 24 union {
bb172083 25 IV xivu_iv;
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26 UV xivu_uv;
27 void * xivu_p1;
bb172083 28 I32 xivu_i32; /* depth, >= 2 indicates recursive call */
69ecfd12 29 HEK * xivu_namehek;
311a25d9 30 } xiv_u;
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31 union {
32 MAGIC* xmg_magic; /* linked list of magicalness */
33 HV* xmg_ourstash; /* Stash for our (when SvPAD_OUR is true) */
34 } xmg_u;
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35 HV* xmg_stash; /* class package */
36
37 HV * xcv_stash;
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38 union {
39 OP * xcv_start;
40 ANY xcv_xsubany;
41 } xcv_start_u;
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42 union {
43 OP * xcv_root;
44 void (*xcv_xsub) (pTHX_ CV*);
45 } xcv_root_u;
8990e307 46 GV * xcv_gv;
57843af0 47 char * xcv_file;
dd2155a4 48 PADLIST * xcv_padlist;
748a9306 49 CV * xcv_outside;
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50 U32 xcv_outside_seq; /* the COP sequence (at the point of our
51 * compilation) in the lexically enclosing
52 * sub */
bb172083 53 cv_flags_t xcv_flags;
79072805 54};
748a9306 55
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NC
56typedef struct {
57 STRLEN xpv_cur; /* length of xp_pv as a C string */
58 STRLEN xpv_len; /* allocated size */
59 union {
60 IV xivu_iv;
61 UV xivu_uv;
62 void * xivu_p1;
63 I32 xivu_i32; /* depth, >= 2 indicates recursive call */
69ecfd12 64 HEK * xivu_namehek;
c84c4652 65 } xiv_u;
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NC
66 union {
67 MAGIC* xmg_magic; /* linked list of magicalness */
68 HV* xmg_ourstash; /* Stash for our (when SvPAD_OUR is true) */
69 } xmg_u;
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70 HV* xmg_stash; /* class package */
71
72 HV * xcv_stash;
73 union {
74 OP * xcv_start;
75 ANY xcv_xsubany;
76 } xcv_start_u;
77 union {
78 OP * xcv_root;
79 void (*xcv_xsub) (pTHX_ CV*);
80 } xcv_root_u;
81 GV * xcv_gv;
82 char * xcv_file;
83 PADLIST * xcv_padlist;
84 CV * xcv_outside;
85 U32 xcv_outside_seq; /* the COP sequence (at the point of our
86 * compilation) in the lexically enclosing
87 * sub */
88 cv_flags_t xcv_flags;
89} xpvcv_allocated;
90
954c1994 91/*
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92=head1 Handy Values
93
954c1994
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94=for apidoc AmU||Nullcv
95Null CV pointer.
96
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97=head1 CV Manipulation Functions
98
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99=for apidoc Am|HV*|CvSTASH|CV* cv
100Returns the stash of the CV.
101
102=cut
103*/
104
79072805 105#define Nullcv Null(CV*)
a5f75d66 106
79072805 107#define CvSTASH(sv) ((XPVCV*)SvANY(sv))->xcv_stash
bf53b3a5 108#define CvSTART(sv) ((XPVCV*)SvANY(sv))->xcv_start_u.xcv_start
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109#define CvROOT(sv) ((XPVCV*)SvANY(sv))->xcv_root_u.xcv_root
110#define CvXSUB(sv) ((XPVCV*)SvANY(sv))->xcv_root_u.xcv_xsub
bf53b3a5 111#define CvXSUBANY(sv) ((XPVCV*)SvANY(sv))->xcv_start_u.xcv_xsubany
8990e307 112#define CvGV(sv) ((XPVCV*)SvANY(sv))->xcv_gv
57843af0 113#define CvFILE(sv) ((XPVCV*)SvANY(sv))->xcv_file
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114#ifdef USE_ITHREADS
115# define CvFILE_set_from_cop(sv, cop) (CvFILE(sv) = savepv(CopFILE(cop)))
116#else
117# define CvFILE_set_from_cop(sv, cop) (CvFILE(sv) = CopFILE(cop))
118#endif
9ec2a764 119#define CvFILEGV(sv) (gv_fetchfile(CvFILE(sv)))
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120#if defined(__GNUC__) && !defined(PERL_GCC_BRACE_GROUPS_FORBIDDEN)
121# define CvDEPTH(sv) (*({const CV *_cv = (CV *)sv; \
122 assert(SvTYPE(_cv) == SVt_PVCV); \
123 &((XPVCV*)SvANY(_cv))->xiv_u.xivu_i32; \
124 }))
125#else
126# define CvDEPTH(sv) ((XPVCV*)SvANY(sv))->xiv_u.xivu_i32
127#endif
79072805 128#define CvPADLIST(sv) ((XPVCV*)SvANY(sv))->xcv_padlist
748a9306 129#define CvOUTSIDE(sv) ((XPVCV*)SvANY(sv))->xcv_outside
a5f75d66 130#define CvFLAGS(sv) ((XPVCV*)SvANY(sv))->xcv_flags
a3985cdc 131#define CvOUTSIDE_SEQ(sv) ((XPVCV*)SvANY(sv))->xcv_outside_seq
a5f75d66 132
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133#define CVf_METHOD 0x0001 /* CV is explicitly marked as a method */
134#define CVf_LOCKED 0x0002 /* CV locks itself or first arg on entry */
135#define CVf_LVALUE 0x0004 /* CV return value can be used as lvalue */
136#define CVf_ASSERTION 0x0008 /* CV called only when asserting */
137
138#define CVf_WEAKOUTSIDE 0x0010 /* CvOUTSIDE isn't ref counted */
139#define CVf_CLONE 0x0020 /* anon CV uses external lexicals */
140#define CVf_CLONED 0x0040 /* a clone of one of those */
141#define CVf_ANON 0x0080 /* CvGV() can't be trusted */
142#define CVf_UNIQUE 0x0100 /* sub is only called once (eg PL_main_cv,
1108974d 143 * require, eval). */
5b4563c8 144#define CVf_NODEBUG 0x0200 /* no DB::sub indirection for this CV
8ebc5c01 145 (esp. useful for special XSUBs) */
5b4563c8 146#define CVf_CONST 0x0400 /* inlinable sub */
f73ef291 147#define CVf_ISXSUB 0x0800 /* CV is an XSUB, not pure perl. */
7dafbf52 148
d3cea301 149/* This symbol for optimised communication between toke.c and op.c: */
06492da6 150#define CVf_BUILTIN_ATTRS (CVf_METHOD|CVf_LOCKED|CVf_LVALUE|CVf_ASSERTION)
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151
152#define CvCLONE(cv) (CvFLAGS(cv) & CVf_CLONE)
153#define CvCLONE_on(cv) (CvFLAGS(cv) |= CVf_CLONE)
154#define CvCLONE_off(cv) (CvFLAGS(cv) &= ~CVf_CLONE)
155
156#define CvCLONED(cv) (CvFLAGS(cv) & CVf_CLONED)
157#define CvCLONED_on(cv) (CvFLAGS(cv) |= CVf_CLONED)
158#define CvCLONED_off(cv) (CvFLAGS(cv) &= ~CVf_CLONED)
159
160#define CvANON(cv) (CvFLAGS(cv) & CVf_ANON)
161#define CvANON_on(cv) (CvFLAGS(cv) |= CVf_ANON)
162#define CvANON_off(cv) (CvFLAGS(cv) &= ~CVf_ANON)
79072805 163
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164#define CvUNIQUE(cv) (CvFLAGS(cv) & CVf_UNIQUE)
165#define CvUNIQUE_on(cv) (CvFLAGS(cv) |= CVf_UNIQUE)
166#define CvUNIQUE_off(cv) (CvFLAGS(cv) &= ~CVf_UNIQUE)
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167
168#define CvNODEBUG(cv) (CvFLAGS(cv) & CVf_NODEBUG)
169#define CvNODEBUG_on(cv) (CvFLAGS(cv) |= CVf_NODEBUG)
170#define CvNODEBUG_off(cv) (CvFLAGS(cv) &= ~CVf_NODEBUG)
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171
172#define CvMETHOD(cv) (CvFLAGS(cv) & CVf_METHOD)
173#define CvMETHOD_on(cv) (CvFLAGS(cv) |= CVf_METHOD)
174#define CvMETHOD_off(cv) (CvFLAGS(cv) &= ~CVf_METHOD)
175
176#define CvLOCKED(cv) (CvFLAGS(cv) & CVf_LOCKED)
177#define CvLOCKED_on(cv) (CvFLAGS(cv) |= CVf_LOCKED)
178#define CvLOCKED_off(cv) (CvFLAGS(cv) &= ~CVf_LOCKED)
1aff0e91 179
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180#define CvLVALUE(cv) (CvFLAGS(cv) & CVf_LVALUE)
181#define CvLVALUE_on(cv) (CvFLAGS(cv) |= CVf_LVALUE)
182#define CvLVALUE_off(cv) (CvFLAGS(cv) &= ~CVf_LVALUE)
183
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184#define CvASSERTION(cv) (CvFLAGS(cv) & CVf_ASSERTION)
185#define CvASSERTION_on(cv) (CvFLAGS(cv) |= CVf_ASSERTION)
186#define CvASSERTION_off(cv) (CvFLAGS(cv) &= ~CVf_ASSERTION)
187
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188#define CvEVAL(cv) (CvUNIQUE(cv) && !SvFAKE(cv))
189#define CvEVAL_on(cv) (CvUNIQUE_on(cv),SvFAKE_off(cv))
190#define CvEVAL_off(cv) CvUNIQUE_off(cv)
191
3c10abe3 192/* BEGIN|CHECK|INIT|UNITCHECK|END */
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GS
193#define CvSPECIAL(cv) (CvUNIQUE(cv) && SvFAKE(cv))
194#define CvSPECIAL_on(cv) (CvUNIQUE_on(cv),SvFAKE_on(cv))
195#define CvSPECIAL_off(cv) (CvUNIQUE_off(cv),SvFAKE_off(cv))
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196
197#define CvCONST(cv) (CvFLAGS(cv) & CVf_CONST)
198#define CvCONST_on(cv) (CvFLAGS(cv) |= CVf_CONST)
199#define CvCONST_off(cv) (CvFLAGS(cv) &= ~CVf_CONST)
a4f1a029 200
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201#define CvWEAKOUTSIDE(cv) (CvFLAGS(cv) & CVf_WEAKOUTSIDE)
202#define CvWEAKOUTSIDE_on(cv) (CvFLAGS(cv) |= CVf_WEAKOUTSIDE)
203#define CvWEAKOUTSIDE_off(cv) (CvFLAGS(cv) &= ~CVf_WEAKOUTSIDE)
204
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205#define CvISXSUB(cv) (CvFLAGS(cv) & CVf_ISXSUB)
206#define CvISXSUB_on(cv) (CvFLAGS(cv) |= CVf_ISXSUB)
207#define CvISXSUB_off(cv) (CvFLAGS(cv) &= ~CVf_ISXSUB)
208
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209/* Flags for newXS_flags */
210#define XS_DYNAMIC_FILENAME 0x01 /* The filename isn't static */
211
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212/*
213=head1 CV reference counts and CvOUTSIDE
214
215=for apidoc m|bool|CvWEAKOUTSIDE|CV *cv
216
217Each CV has a pointer, C<CvOUTSIDE()>, to its lexically enclosing
218CV (if any). Because pointers to anonymous sub prototypes are
219stored in C<&> pad slots, it is a possible to get a circular reference,
220with the parent pointing to the child and vice-versa. To avoid the
221ensuing memory leak, we do not increment the reference count of the CV
222pointed to by C<CvOUTSIDE> in the I<one specific instance> that the parent
223has a C<&> pad slot pointing back to us. In this case, we set the
224C<CvWEAKOUTSIDE> flag in the child. This allows us to determine under what
225circumstances we should decrement the refcount of the parent when freeing
226the child.
227
eeb8d49e 228There is a further complication with non-closure anonymous subs (i.e. those
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DM
229that do not refer to any lexicals outside that sub). In this case, the
230anonymous prototype is shared rather than being cloned. This has the
231consequence that the parent may be freed while there are still active
232children, eg
233
234 BEGIN { $a = sub { eval '$x' } }
235
236In this case, the BEGIN is freed immediately after execution since there
237are no active references to it: the anon sub prototype has
238C<CvWEAKOUTSIDE> set since it's not a closure, and $a points to the same
239CV, so it doesn't contribute to BEGIN's refcount either. When $a is
240executed, the C<eval '$x'> causes the chain of C<CvOUTSIDE>s to be followed,
241and the freed BEGIN is accessed.
242
243To avoid this, whenever a CV and its associated pad is freed, any
244C<&> entries in the pad are explicitly removed from the pad, and if the
245refcount of the pointed-to anon sub is still positive, then that
246child's C<CvOUTSIDE> is set to point to its grandparent. This will only
247occur in the single specific case of a non-closure anon prototype
248having one or more active references (such as C<$a> above).
249
250One other thing to consider is that a CV may be merely undefined
251rather than freed, eg C<undef &foo>. In this case, its refcount may
252not have reached zero, but we still delete its pad and its C<CvROOT> etc.
253Since various children may still have their C<CvOUTSIDE> pointing at this
254undefined CV, we keep its own C<CvOUTSIDE> for the time being, so that
255the chain of lexical scopes is unbroken. For example, the following
256should print 123:
257
258 my $x = 123;
259 sub tmp { sub { eval '$x' } }
260 my $a = tmp();
261 undef &tmp;
262 print $a->();
263
264=cut
265*/
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NC
266
267/*
268 * Local variables:
269 * c-indentation-style: bsd
270 * c-basic-offset: 4
271 * indent-tabs-mode: t
272 * End:
273 *
274 * ex: set ts=8 sts=4 sw=4 noet:
275 */