Commit | Line | Data |
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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 |
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 | */ |
10 | ||
7c60e434 | 11 | /* This structure must the beginning of XPVFM in sv.h */ |
44a8e56a | 12 | |
79072805 | 13 | struct xpvcv { |
58430790 NC |
14 | union { |
15 | NV xnv_nv; /* numeric value, if any */ | |
16 | HV * xgv_stash; | |
17 | } xnv_u; | |
79072805 LW |
18 | STRLEN xpv_cur; /* length of xp_pv as a C string */ |
19 | STRLEN xpv_len; /* allocated size */ | |
e4305a63 | 20 | union { |
bb172083 | 21 | IV xivu_iv; |
311a25d9 NC |
22 | UV xivu_uv; |
23 | void * xivu_p1; | |
bb172083 | 24 | I32 xivu_i32; /* depth, >= 2 indicates recursive call */ |
69ecfd12 | 25 | HEK * xivu_namehek; |
311a25d9 | 26 | } xiv_u; |
e736a858 NC |
27 | union { |
28 | MAGIC* xmg_magic; /* linked list of magicalness */ | |
29 | HV* xmg_ourstash; /* Stash for our (when SvPAD_OUR is true) */ | |
30 | } xmg_u; | |
79072805 LW |
31 | HV* xmg_stash; /* class package */ |
32 | ||
33 | HV * xcv_stash; | |
bf53b3a5 NC |
34 | union { |
35 | OP * xcv_start; | |
36 | ANY xcv_xsubany; | |
37 | } xcv_start_u; | |
d04ba589 NC |
38 | union { |
39 | OP * xcv_root; | |
40 | void (*xcv_xsub) (pTHX_ CV*); | |
41 | } xcv_root_u; | |
8990e307 | 42 | GV * xcv_gv; |
57843af0 | 43 | char * xcv_file; |
dd2155a4 | 44 | PADLIST * xcv_padlist; |
748a9306 | 45 | CV * xcv_outside; |
a3985cdc DM |
46 | U32 xcv_outside_seq; /* the COP sequence (at the point of our |
47 | * compilation) in the lexically enclosing | |
48 | * sub */ | |
bb172083 | 49 | cv_flags_t xcv_flags; |
79072805 | 50 | }; |
748a9306 | 51 | |
c84c4652 NC |
52 | typedef struct { |
53 | STRLEN xpv_cur; /* length of xp_pv as a C string */ | |
54 | STRLEN xpv_len; /* allocated size */ | |
55 | union { | |
56 | IV xivu_iv; | |
57 | UV xivu_uv; | |
58 | void * xivu_p1; | |
59 | I32 xivu_i32; /* depth, >= 2 indicates recursive call */ | |
69ecfd12 | 60 | HEK * xivu_namehek; |
c84c4652 | 61 | } xiv_u; |
e736a858 NC |
62 | union { |
63 | MAGIC* xmg_magic; /* linked list of magicalness */ | |
64 | HV* xmg_ourstash; /* Stash for our (when SvPAD_OUR is true) */ | |
65 | } xmg_u; | |
c84c4652 NC |
66 | HV* xmg_stash; /* class package */ |
67 | ||
68 | HV * xcv_stash; | |
69 | union { | |
70 | OP * xcv_start; | |
71 | ANY xcv_xsubany; | |
72 | } xcv_start_u; | |
73 | union { | |
74 | OP * xcv_root; | |
75 | void (*xcv_xsub) (pTHX_ CV*); | |
76 | } xcv_root_u; | |
77 | GV * xcv_gv; | |
78 | char * xcv_file; | |
79 | PADLIST * xcv_padlist; | |
80 | CV * xcv_outside; | |
81 | U32 xcv_outside_seq; /* the COP sequence (at the point of our | |
82 | * compilation) in the lexically enclosing | |
83 | * sub */ | |
84 | cv_flags_t xcv_flags; | |
85 | } xpvcv_allocated; | |
86 | ||
954c1994 | 87 | /* |
ccfc67b7 JH |
88 | =head1 Handy Values |
89 | ||
954c1994 GS |
90 | =for apidoc AmU||Nullcv |
91 | Null CV pointer. | |
92 | ||
ccfc67b7 JH |
93 | =head1 CV Manipulation Functions |
94 | ||
954c1994 GS |
95 | =for apidoc Am|HV*|CvSTASH|CV* cv |
96 | Returns the stash of the CV. | |
97 | ||
98 | =cut | |
99 | */ | |
100 | ||
79072805 | 101 | #define Nullcv Null(CV*) |
a5f75d66 | 102 | |
79072805 | 103 | #define CvSTASH(sv) ((XPVCV*)SvANY(sv))->xcv_stash |
bf53b3a5 | 104 | #define CvSTART(sv) ((XPVCV*)SvANY(sv))->xcv_start_u.xcv_start |
d04ba589 NC |
105 | #define CvROOT(sv) ((XPVCV*)SvANY(sv))->xcv_root_u.xcv_root |
106 | #define CvXSUB(sv) ((XPVCV*)SvANY(sv))->xcv_root_u.xcv_xsub | |
bf53b3a5 | 107 | #define CvXSUBANY(sv) ((XPVCV*)SvANY(sv))->xcv_start_u.xcv_xsubany |
8990e307 | 108 | #define CvGV(sv) ((XPVCV*)SvANY(sv))->xcv_gv |
57843af0 | 109 | #define CvFILE(sv) ((XPVCV*)SvANY(sv))->xcv_file |
a636914a RH |
110 | #ifdef USE_ITHREADS |
111 | # define CvFILE_set_from_cop(sv, cop) (CvFILE(sv) = savepv(CopFILE(cop))) | |
112 | #else | |
113 | # define CvFILE_set_from_cop(sv, cop) (CvFILE(sv) = CopFILE(cop)) | |
114 | #endif | |
9ec2a764 | 115 | #define CvFILEGV(sv) (gv_fetchfile(CvFILE(sv))) |
bb172083 NC |
116 | #if defined(__GNUC__) && !defined(PERL_GCC_BRACE_GROUPS_FORBIDDEN) |
117 | # define CvDEPTH(sv) (*({const CV *_cv = (CV *)sv; \ | |
118 | assert(SvTYPE(_cv) == SVt_PVCV); \ | |
119 | &((XPVCV*)SvANY(_cv))->xiv_u.xivu_i32; \ | |
120 | })) | |
121 | #else | |
122 | # define CvDEPTH(sv) ((XPVCV*)SvANY(sv))->xiv_u.xivu_i32 | |
123 | #endif | |
79072805 | 124 | #define CvPADLIST(sv) ((XPVCV*)SvANY(sv))->xcv_padlist |
748a9306 | 125 | #define CvOUTSIDE(sv) ((XPVCV*)SvANY(sv))->xcv_outside |
a5f75d66 | 126 | #define CvFLAGS(sv) ((XPVCV*)SvANY(sv))->xcv_flags |
a3985cdc | 127 | #define CvOUTSIDE_SEQ(sv) ((XPVCV*)SvANY(sv))->xcv_outside_seq |
a5f75d66 | 128 | |
5b4563c8 NC |
129 | #define CVf_METHOD 0x0001 /* CV is explicitly marked as a method */ |
130 | #define CVf_LOCKED 0x0002 /* CV locks itself or first arg on entry */ | |
131 | #define CVf_LVALUE 0x0004 /* CV return value can be used as lvalue */ | |
132 | #define CVf_ASSERTION 0x0008 /* CV called only when asserting */ | |
133 | ||
134 | #define CVf_WEAKOUTSIDE 0x0010 /* CvOUTSIDE isn't ref counted */ | |
135 | #define CVf_CLONE 0x0020 /* anon CV uses external lexicals */ | |
136 | #define CVf_CLONED 0x0040 /* a clone of one of those */ | |
137 | #define CVf_ANON 0x0080 /* CvGV() can't be trusted */ | |
138 | #define CVf_UNIQUE 0x0100 /* sub is only called once (eg PL_main_cv, | |
1108974d | 139 | * require, eval). */ |
5b4563c8 | 140 | #define CVf_NODEBUG 0x0200 /* no DB::sub indirection for this CV |
8ebc5c01 | 141 | (esp. useful for special XSUBs) */ |
5b4563c8 | 142 | #define CVf_CONST 0x0400 /* inlinable sub */ |
f73ef291 | 143 | #define CVf_ISXSUB 0x0800 /* CV is an XSUB, not pure perl. */ |
7dafbf52 | 144 | |
d3cea301 | 145 | /* This symbol for optimised communication between toke.c and op.c: */ |
06492da6 | 146 | #define CVf_BUILTIN_ATTRS (CVf_METHOD|CVf_LOCKED|CVf_LVALUE|CVf_ASSERTION) |
a5f75d66 AD |
147 | |
148 | #define CvCLONE(cv) (CvFLAGS(cv) & CVf_CLONE) | |
149 | #define CvCLONE_on(cv) (CvFLAGS(cv) |= CVf_CLONE) | |
150 | #define CvCLONE_off(cv) (CvFLAGS(cv) &= ~CVf_CLONE) | |
151 | ||
152 | #define CvCLONED(cv) (CvFLAGS(cv) & CVf_CLONED) | |
153 | #define CvCLONED_on(cv) (CvFLAGS(cv) |= CVf_CLONED) | |
154 | #define CvCLONED_off(cv) (CvFLAGS(cv) &= ~CVf_CLONED) | |
155 | ||
156 | #define CvANON(cv) (CvFLAGS(cv) & CVf_ANON) | |
157 | #define CvANON_on(cv) (CvFLAGS(cv) |= CVf_ANON) | |
158 | #define CvANON_off(cv) (CvFLAGS(cv) &= ~CVf_ANON) | |
79072805 | 159 | |
07055b4c CS |
160 | #define CvUNIQUE(cv) (CvFLAGS(cv) & CVf_UNIQUE) |
161 | #define CvUNIQUE_on(cv) (CvFLAGS(cv) |= CVf_UNIQUE) | |
162 | #define CvUNIQUE_off(cv) (CvFLAGS(cv) &= ~CVf_UNIQUE) | |
8ebc5c01 | 163 | |
164 | #define CvNODEBUG(cv) (CvFLAGS(cv) & CVf_NODEBUG) | |
165 | #define CvNODEBUG_on(cv) (CvFLAGS(cv) |= CVf_NODEBUG) | |
166 | #define CvNODEBUG_off(cv) (CvFLAGS(cv) &= ~CVf_NODEBUG) | |
77a005ab MB |
167 | |
168 | #define CvMETHOD(cv) (CvFLAGS(cv) & CVf_METHOD) | |
169 | #define CvMETHOD_on(cv) (CvFLAGS(cv) |= CVf_METHOD) | |
170 | #define CvMETHOD_off(cv) (CvFLAGS(cv) &= ~CVf_METHOD) | |
171 | ||
172 | #define CvLOCKED(cv) (CvFLAGS(cv) & CVf_LOCKED) | |
173 | #define CvLOCKED_on(cv) (CvFLAGS(cv) |= CVf_LOCKED) | |
174 | #define CvLOCKED_off(cv) (CvFLAGS(cv) &= ~CVf_LOCKED) | |
1aff0e91 | 175 | |
cd06dffe GS |
176 | #define CvLVALUE(cv) (CvFLAGS(cv) & CVf_LVALUE) |
177 | #define CvLVALUE_on(cv) (CvFLAGS(cv) |= CVf_LVALUE) | |
178 | #define CvLVALUE_off(cv) (CvFLAGS(cv) &= ~CVf_LVALUE) | |
179 | ||
06492da6 SF |
180 | #define CvASSERTION(cv) (CvFLAGS(cv) & CVf_ASSERTION) |
181 | #define CvASSERTION_on(cv) (CvFLAGS(cv) |= CVf_ASSERTION) | |
182 | #define CvASSERTION_off(cv) (CvFLAGS(cv) &= ~CVf_ASSERTION) | |
183 | ||
1aff0e91 GS |
184 | #define CvEVAL(cv) (CvUNIQUE(cv) && !SvFAKE(cv)) |
185 | #define CvEVAL_on(cv) (CvUNIQUE_on(cv),SvFAKE_off(cv)) | |
186 | #define CvEVAL_off(cv) CvUNIQUE_off(cv) | |
187 | ||
bec31f9a | 188 | /* BEGIN|CHECK|INIT|END */ |
1aff0e91 GS |
189 | #define CvSPECIAL(cv) (CvUNIQUE(cv) && SvFAKE(cv)) |
190 | #define CvSPECIAL_on(cv) (CvUNIQUE_on(cv),SvFAKE_on(cv)) | |
191 | #define CvSPECIAL_off(cv) (CvUNIQUE_off(cv),SvFAKE_off(cv)) | |
beab0874 JT |
192 | |
193 | #define CvCONST(cv) (CvFLAGS(cv) & CVf_CONST) | |
194 | #define CvCONST_on(cv) (CvFLAGS(cv) |= CVf_CONST) | |
195 | #define CvCONST_off(cv) (CvFLAGS(cv) &= ~CVf_CONST) | |
a4f1a029 | 196 | |
7dafbf52 DM |
197 | #define CvWEAKOUTSIDE(cv) (CvFLAGS(cv) & CVf_WEAKOUTSIDE) |
198 | #define CvWEAKOUTSIDE_on(cv) (CvFLAGS(cv) |= CVf_WEAKOUTSIDE) | |
199 | #define CvWEAKOUTSIDE_off(cv) (CvFLAGS(cv) &= ~CVf_WEAKOUTSIDE) | |
200 | ||
d04ba589 NC |
201 | #define CvISXSUB(cv) (CvFLAGS(cv) & CVf_ISXSUB) |
202 | #define CvISXSUB_on(cv) (CvFLAGS(cv) |= CVf_ISXSUB) | |
203 | #define CvISXSUB_off(cv) (CvFLAGS(cv) &= ~CVf_ISXSUB) | |
204 | ||
7dafbf52 DM |
205 | /* |
206 | =head1 CV reference counts and CvOUTSIDE | |
207 | ||
208 | =for apidoc m|bool|CvWEAKOUTSIDE|CV *cv | |
209 | ||
210 | Each CV has a pointer, C<CvOUTSIDE()>, to its lexically enclosing | |
211 | CV (if any). Because pointers to anonymous sub prototypes are | |
212 | stored in C<&> pad slots, it is a possible to get a circular reference, | |
213 | with the parent pointing to the child and vice-versa. To avoid the | |
214 | ensuing memory leak, we do not increment the reference count of the CV | |
215 | pointed to by C<CvOUTSIDE> in the I<one specific instance> that the parent | |
216 | has a C<&> pad slot pointing back to us. In this case, we set the | |
217 | C<CvWEAKOUTSIDE> flag in the child. This allows us to determine under what | |
218 | circumstances we should decrement the refcount of the parent when freeing | |
219 | the child. | |
220 | ||
eeb8d49e | 221 | There is a further complication with non-closure anonymous subs (i.e. those |
7dafbf52 DM |
222 | that do not refer to any lexicals outside that sub). In this case, the |
223 | anonymous prototype is shared rather than being cloned. This has the | |
224 | consequence that the parent may be freed while there are still active | |
225 | children, eg | |
226 | ||
227 | BEGIN { $a = sub { eval '$x' } } | |
228 | ||
229 | In this case, the BEGIN is freed immediately after execution since there | |
230 | are no active references to it: the anon sub prototype has | |
231 | C<CvWEAKOUTSIDE> set since it's not a closure, and $a points to the same | |
232 | CV, so it doesn't contribute to BEGIN's refcount either. When $a is | |
233 | executed, the C<eval '$x'> causes the chain of C<CvOUTSIDE>s to be followed, | |
234 | and the freed BEGIN is accessed. | |
235 | ||
236 | To avoid this, whenever a CV and its associated pad is freed, any | |
237 | C<&> entries in the pad are explicitly removed from the pad, and if the | |
238 | refcount of the pointed-to anon sub is still positive, then that | |
239 | child's C<CvOUTSIDE> is set to point to its grandparent. This will only | |
240 | occur in the single specific case of a non-closure anon prototype | |
241 | having one or more active references (such as C<$a> above). | |
242 | ||
243 | One other thing to consider is that a CV may be merely undefined | |
244 | rather than freed, eg C<undef &foo>. In this case, its refcount may | |
245 | not have reached zero, but we still delete its pad and its C<CvROOT> etc. | |
246 | Since various children may still have their C<CvOUTSIDE> pointing at this | |
247 | undefined CV, we keep its own C<CvOUTSIDE> for the time being, so that | |
248 | the chain of lexical scopes is unbroken. For example, the following | |
249 | should print 123: | |
250 | ||
251 | my $x = 123; | |
252 | sub tmp { sub { eval '$x' } } | |
253 | my $a = tmp(); | |
254 | undef &tmp; | |
255 | print $a->(); | |
256 | ||
257 | =cut | |
258 | */ | |
102d3b8a NC |
259 | |
260 | /* | |
261 | * Local variables: | |
262 | * c-indentation-style: bsd | |
263 | * c-basic-offset: 4 | |
264 | * indent-tabs-mode: t | |
265 | * End: | |
266 | * | |
267 | * ex: set ts=8 sts=4 sw=4 noet: | |
268 | */ |