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[perl5.git] / op.c
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4b88f280 1#line 2 "op.c"
a0d0e21e 2/* op.c
79072805 3 *
1129b882
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4 * Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
5 * 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 by Larry Wall and others
79072805
LW
6 *
7 * You may distribute under the terms of either the GNU General Public
8 * License or the Artistic License, as specified in the README file.
9 *
a0d0e21e
LW
10 */
11
12/*
4ac71550
TC
13 * 'You see: Mr. Drogo, he married poor Miss Primula Brandybuck. She was
14 * our Mr. Bilbo's first cousin on the mother's side (her mother being the
15 * youngest of the Old Took's daughters); and Mr. Drogo was his second
16 * cousin. So Mr. Frodo is his first *and* second cousin, once removed
17 * either way, as the saying is, if you follow me.' --the Gaffer
18 *
19 * [p.23 of _The Lord of the Rings_, I/i: "A Long-Expected Party"]
79072805
LW
20 */
21
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DM
22/* This file contains the functions that create, manipulate and optimize
23 * the OP structures that hold a compiled perl program.
24 *
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DM
25 * Note that during the build of miniperl, a temporary copy of this file
26 * is made, called opmini.c.
27 *
28 * A Perl program is compiled into a tree of OP nodes. Each op contains:
29 * * structural OP pointers to its children and siblings (op_sibling,
30 * op_first etc) that define the tree structure;
31 * * execution order OP pointers (op_next, plus sometimes op_other,
32 * op_lastop etc) that define the execution sequence plus variants;
33 * * a pointer to the C "pp" function that would execute the op;
34 * * any data specific to that op.
35 * For example, an OP_CONST op points to the pp_const() function and to an
36 * SV containing the constant value. When pp_const() is executed, its job
37 * is to push that SV onto the stack.
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DM
38 *
39 * OPs are mainly created by the newFOO() functions, which are mainly
40 * called from the parser (in perly.y) as the code is parsed. For example
41 * the Perl code $a + $b * $c would cause the equivalent of the following
42 * to be called (oversimplifying a bit):
43 *
44 * newBINOP(OP_ADD, flags,
45 * newSVREF($a),
46 * newBINOP(OP_MULTIPLY, flags, newSVREF($b), newSVREF($c))
47 * )
48 *
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DM
49 * As the parser reduces low-level rules, it creates little op subtrees;
50 * as higher-level rules are resolved, these subtrees get joined together
51 * as branches on a bigger subtree, until eventually a top-level rule like
52 * a subroutine definition is reduced, at which point there is one large
53 * parse tree left.
54 *
55 * The execution order pointers (op_next) are generated as the subtrees
56 * are joined together. Consider this sub-expression: A*B + C/D: at the
57 * point when it's just been parsed, the op tree looks like:
58 *
59 * [+]
60 * |
61 * [*]------[/]
62 * | |
63 * A---B C---D
64 *
65 * with the intended execution order being:
66 *
67 * [PREV] => A => B => [*] => C => D => [/] => [+] => [NEXT]
68 *
69 * At this point all the nodes' op_next pointers will have been set,
70 * except that:
71 * * we don't know what the [NEXT] node will be yet;
72 * * we don't know what the [PREV] node will be yet, but when it gets
73 * created and needs its op_next set, it needs to be set to point to
74 * A, which is non-obvious.
75 * To handle both those cases, we temporarily set the top node's
76 * op_next to point to the first node to be executed in this subtree (A in
77 * this case). This means that initially a subtree's op_next chain,
78 * starting from the top node, will visit each node in execution sequence
79 * then point back at the top node.
80 * When we embed this subtree in a larger tree, its top op_next is used
81 * to get the start node, then is set to point to its new neighbour.
82 * For example the two separate [*],A,B and [/],C,D subtrees would
83 * initially have had:
84 * [*] => A; A => B; B => [*]
85 * and
86 * [/] => C; C => D; D => [/]
87 * When these two subtrees were joined together to make the [+] subtree,
88 * [+]'s op_next was set to [*]'s op_next, i.e. A; then [*]'s op_next was
89 * set to point to [/]'s op_next, i.e. C.
90 *
91 * This op_next linking is done by the LINKLIST() macro and its underlying
92 * op_linklist() function. Given a top-level op, if its op_next is
93 * non-null, it's already been linked, so leave it. Otherwise link it with
94 * its children as described above, possibly recursively if any of the
95 * children have a null op_next.
96 *
97 * In summary: given a subtree, its top-level node's op_next will either
98 * be:
99 * NULL: the subtree hasn't been LINKLIST()ed yet;
100 * fake: points to the start op for this subtree;
101 * real: once the subtree has been embedded into a larger tree
166f8a29 102 */
ccfc67b7 103
61b743bb 104/*
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105
106Here's an older description from Larry.
107
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108Perl's compiler is essentially a 3-pass compiler with interleaved phases:
109
110 A bottom-up pass
111 A top-down pass
112 An execution-order pass
113
114The bottom-up pass is represented by all the "newOP" routines and
115the ck_ routines. The bottom-upness is actually driven by yacc.
116So at the point that a ck_ routine fires, we have no idea what the
117context is, either upward in the syntax tree, or either forward or
118backward in the execution order. (The bottom-up parser builds that
119part of the execution order it knows about, but if you follow the "next"
120links around, you'll find it's actually a closed loop through the
ef9da979 121top level node.)
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122
123Whenever the bottom-up parser gets to a node that supplies context to
124its components, it invokes that portion of the top-down pass that applies
125to that part of the subtree (and marks the top node as processed, so
126if a node further up supplies context, it doesn't have to take the
127plunge again). As a particular subcase of this, as the new node is
128built, it takes all the closed execution loops of its subcomponents
129and links them into a new closed loop for the higher level node. But
130it's still not the real execution order.
131
132The actual execution order is not known till we get a grammar reduction
133to a top-level unit like a subroutine or file that will be called by
134"name" rather than via a "next" pointer. At that point, we can call
135into peep() to do that code's portion of the 3rd pass. It has to be
136recursive, but it's recursive on basic blocks, not on tree nodes.
137*/
138
06e0342d 139/* To implement user lexical pragmas, there needs to be a way at run time to
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140 get the compile time state of %^H for that block. Storing %^H in every
141 block (or even COP) would be very expensive, so a different approach is
142 taken. The (running) state of %^H is serialised into a tree of HE-like
143 structs. Stores into %^H are chained onto the current leaf as a struct
144 refcounted_he * with the key and the value. Deletes from %^H are saved
145 with a value of PL_sv_placeholder. The state of %^H at any point can be
146 turned back into a regular HV by walking back up the tree from that point's
06e0342d 147 leaf, ignoring any key you've already seen (placeholder or not), storing
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NC
148 the rest into the HV structure, then removing the placeholders. Hence
149 memory is only used to store the %^H deltas from the enclosing COP, rather
150 than the entire %^H on each COP.
151
152 To cause actions on %^H to write out the serialisation records, it has
153 magic type 'H'. This magic (itself) does nothing, but its presence causes
154 the values to gain magic type 'h', which has entries for set and clear.
c28fe1ec 155 C<Perl_magic_sethint> updates C<PL_compiling.cop_hints_hash> with a store
34795b44 156 record, with deletes written by C<Perl_magic_clearhint>. C<SAVEHINTS>
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157 saves the current C<PL_compiling.cop_hints_hash> on the save stack, so that
158 it will be correctly restored when any inner compiling scope is exited.
b3ca2e83
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159*/
160
79072805 161#include "EXTERN.h"
864dbfa3 162#define PERL_IN_OP_C
79072805 163#include "perl.h"
77ca0c92 164#include "keywords.h"
2846acbf 165#include "feature.h"
74529a43 166#include "regcomp.h"
79072805 167
16c91539 168#define CALL_PEEP(o) PL_peepp(aTHX_ o)
1a0a2ba9 169#define CALL_RPEEP(o) PL_rpeepp(aTHX_ o)
16c91539 170#define CALL_OPFREEHOOK(o) if (PL_opfreehook) PL_opfreehook(aTHX_ o)
a2efc822 171
5068f264 172static const char array_passed_to_stat[] = "Array passed to stat will be coerced to a scalar";
637494ac 173
aa9d1253
TC
174/* Used to avoid recursion through the op tree in scalarvoid() and
175 op_free()
176*/
177
178#define DEFERRED_OP_STEP 100
179#define DEFER_OP(o) \
180 STMT_START { \
181 if (UNLIKELY(defer_ix == (defer_stack_alloc-1))) { \
182 defer_stack_alloc += DEFERRED_OP_STEP; \
183 assert(defer_stack_alloc > 0); \
184 Renew(defer_stack, defer_stack_alloc, OP *); \
185 } \
186 defer_stack[++defer_ix] = o; \
187 } STMT_END
188
189#define POP_DEFERRED_OP() (defer_ix >= 0 ? defer_stack[defer_ix--] : (OP *)NULL)
190
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191/* remove any leading "empty" ops from the op_next chain whose first
192 * node's address is stored in op_p. Store the updated address of the
193 * first node in op_p.
194 */
195
196STATIC void
dc3bf405 197S_prune_chain_head(OP** op_p)
72621f84
DM
198{
199 while (*op_p
200 && ( (*op_p)->op_type == OP_NULL
201 || (*op_p)->op_type == OP_SCOPE
202 || (*op_p)->op_type == OP_SCALAR
203 || (*op_p)->op_type == OP_LINESEQ)
204 )
205 *op_p = (*op_p)->op_next;
206}
207
208
8be227ab
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209/* See the explanatory comments above struct opslab in op.h. */
210
7aef8e5b 211#ifdef PERL_DEBUG_READONLY_OPS
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212# define PERL_SLAB_SIZE 128
213# define PERL_MAX_SLAB_SIZE 4096
214# include <sys/mman.h>
7aef8e5b 215#endif
3107b51f 216
7aef8e5b 217#ifndef PERL_SLAB_SIZE
8be227ab 218# define PERL_SLAB_SIZE 64
7aef8e5b
FC
219#endif
220#ifndef PERL_MAX_SLAB_SIZE
e6cee8c0 221# define PERL_MAX_SLAB_SIZE 2048
7aef8e5b 222#endif
8be227ab
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223
224/* rounds up to nearest pointer */
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225#define SIZE_TO_PSIZE(x) (((x) + sizeof(I32 *) - 1)/sizeof(I32 *))
226#define DIFF(o,p) ((size_t)((I32 **)(p) - (I32**)(o)))
8be227ab
FC
227
228static OPSLAB *
229S_new_slab(pTHX_ size_t sz)
230{
7aef8e5b 231#ifdef PERL_DEBUG_READONLY_OPS
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232 OPSLAB *slab = (OPSLAB *) mmap(0, sz * sizeof(I32 *),
233 PROT_READ|PROT_WRITE,
234 MAP_ANON|MAP_PRIVATE, -1, 0);
235 DEBUG_m(PerlIO_printf(Perl_debug_log, "mapped %lu at %p\n",
236 (unsigned long) sz, slab));
237 if (slab == MAP_FAILED) {
238 perror("mmap failed");
239 abort();
240 }
241 slab->opslab_size = (U16)sz;
7aef8e5b 242#else
8be227ab 243 OPSLAB *slab = (OPSLAB *)PerlMemShared_calloc(sz, sizeof(I32 *));
7aef8e5b 244#endif
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BF
245#ifndef WIN32
246 /* The context is unused in non-Windows */
247 PERL_UNUSED_CONTEXT;
248#endif
8be227ab
FC
249 slab->opslab_first = (OPSLOT *)((I32 **)slab + sz - 1);
250 return slab;
251}
252
e7372881
FC
253/* requires double parens and aTHX_ */
254#define DEBUG_S_warn(args) \
255 DEBUG_S( \
256 PerlIO_printf(Perl_debug_log, "%s", SvPVx_nolen(Perl_mess args)) \
257 )
258
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FC
259void *
260Perl_Slab_Alloc(pTHX_ size_t sz)
261{
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FC
262 OPSLAB *slab;
263 OPSLAB *slab2;
264 OPSLOT *slot;
265 OP *o;
5cb52f30 266 size_t opsz, space;
8be227ab 267
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NC
268 /* We only allocate ops from the slab during subroutine compilation.
269 We find the slab via PL_compcv, hence that must be non-NULL. It could
270 also be pointing to a subroutine which is now fully set up (CvROOT()
271 pointing to the top of the optree for that sub), or a subroutine
272 which isn't using the slab allocator. If our sanity checks aren't met,
273 don't use a slab, but allocate the OP directly from the heap. */
8be227ab
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274 if (!PL_compcv || CvROOT(PL_compcv)
275 || (CvSTART(PL_compcv) && !CvSLABBED(PL_compcv)))
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DM
276 {
277 o = (OP*)PerlMemShared_calloc(1, sz);
278 goto gotit;
279 }
8be227ab 280
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281 /* While the subroutine is under construction, the slabs are accessed via
282 CvSTART(), to avoid needing to expand PVCV by one pointer for something
283 unneeded at runtime. Once a subroutine is constructed, the slabs are
284 accessed via CvROOT(). So if CvSTART() is NULL, no slab has been
285 allocated yet. See the commit message for 8be227ab5eaa23f2 for more
286 details. */
287 if (!CvSTART(PL_compcv)) {
8be227ab
FC
288 CvSTART(PL_compcv) =
289 (OP *)(slab = S_new_slab(aTHX_ PERL_SLAB_SIZE));
290 CvSLABBED_on(PL_compcv);
291 slab->opslab_refcnt = 2; /* one for the CV; one for the new OP */
292 }
293 else ++(slab = (OPSLAB *)CvSTART(PL_compcv))->opslab_refcnt;
294
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FC
295 opsz = SIZE_TO_PSIZE(sz);
296 sz = opsz + OPSLOT_HEADER_P;
8be227ab 297
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NC
298 /* The slabs maintain a free list of OPs. In particular, constant folding
299 will free up OPs, so it makes sense to re-use them where possible. A
300 freed up slot is used in preference to a new allocation. */
8be227ab
FC
301 if (slab->opslab_freed) {
302 OP **too = &slab->opslab_freed;
303 o = *too;
eb212a1c 304 DEBUG_S_warn((aTHX_ "found free op at %p, slab %p", (void*)o, (void*)slab));
8be227ab 305 while (o && DIFF(OpSLOT(o), OpSLOT(o)->opslot_next) < sz) {
e7372881 306 DEBUG_S_warn((aTHX_ "Alas! too small"));
8be227ab 307 o = *(too = &o->op_next);
eb212a1c 308 if (o) { DEBUG_S_warn((aTHX_ "found another free op at %p", (void*)o)); }
8be227ab
FC
309 }
310 if (o) {
311 *too = o->op_next;
5cb52f30 312 Zero(o, opsz, I32 *);
8be227ab 313 o->op_slabbed = 1;
29e61fd9 314 goto gotit;
8be227ab
FC
315 }
316 }
317
7aef8e5b 318#define INIT_OPSLOT \
8be227ab
FC
319 slot->opslot_slab = slab; \
320 slot->opslot_next = slab2->opslab_first; \
321 slab2->opslab_first = slot; \
322 o = &slot->opslot_op; \
323 o->op_slabbed = 1
324
325 /* The partially-filled slab is next in the chain. */
326 slab2 = slab->opslab_next ? slab->opslab_next : slab;
327 if ((space = DIFF(&slab2->opslab_slots, slab2->opslab_first)) < sz) {
328 /* Remaining space is too small. */
329
8be227ab
FC
330 /* If we can fit a BASEOP, add it to the free chain, so as not
331 to waste it. */
332 if (space >= SIZE_TO_PSIZE(sizeof(OP)) + OPSLOT_HEADER_P) {
333 slot = &slab2->opslab_slots;
334 INIT_OPSLOT;
335 o->op_type = OP_FREED;
336 o->op_next = slab->opslab_freed;
337 slab->opslab_freed = o;
338 }
339
340 /* Create a new slab. Make this one twice as big. */
341 slot = slab2->opslab_first;
342 while (slot->opslot_next) slot = slot->opslot_next;
af7751f6
FC
343 slab2 = S_new_slab(aTHX_
344 (DIFF(slab2, slot)+1)*2 > PERL_MAX_SLAB_SIZE
e6cee8c0 345 ? PERL_MAX_SLAB_SIZE
af7751f6 346 : (DIFF(slab2, slot)+1)*2);
9963ffa2
FC
347 slab2->opslab_next = slab->opslab_next;
348 slab->opslab_next = slab2;
8be227ab
FC
349 }
350 assert(DIFF(&slab2->opslab_slots, slab2->opslab_first) >= sz);
351
352 /* Create a new op slot */
353 slot = (OPSLOT *)((I32 **)slab2->opslab_first - sz);
354 assert(slot >= &slab2->opslab_slots);
51c777ca
FC
355 if (DIFF(&slab2->opslab_slots, slot)
356 < SIZE_TO_PSIZE(sizeof(OP)) + OPSLOT_HEADER_P)
357 slot = &slab2->opslab_slots;
8be227ab 358 INIT_OPSLOT;
eb212a1c 359 DEBUG_S_warn((aTHX_ "allocating op at %p, slab %p", (void*)o, (void*)slab));
29e61fd9
DM
360
361 gotit:
93059c1a 362#ifdef PERL_OP_PARENT
87b5a8b9
DM
363 /* moresib == 0, op_sibling == 0 implies a solitary unattached op */
364 assert(!o->op_moresib);
86cd3a13 365 assert(!o->op_sibparent);
93059c1a 366#endif
29e61fd9 367
8be227ab
FC
368 return (void *)o;
369}
370
7aef8e5b 371#undef INIT_OPSLOT
8be227ab 372
7aef8e5b 373#ifdef PERL_DEBUG_READONLY_OPS
3107b51f
FC
374void
375Perl_Slab_to_ro(pTHX_ OPSLAB *slab)
376{
377 PERL_ARGS_ASSERT_SLAB_TO_RO;
378
379 if (slab->opslab_readonly) return;
380 slab->opslab_readonly = 1;
381 for (; slab; slab = slab->opslab_next) {
382 /*DEBUG_U(PerlIO_printf(Perl_debug_log,"mprotect ->ro %lu at %p\n",
383 (unsigned long) slab->opslab_size, slab));*/
384 if (mprotect(slab, slab->opslab_size * sizeof(I32 *), PROT_READ))
385 Perl_warn(aTHX_ "mprotect for %p %lu failed with %d", slab,
386 (unsigned long)slab->opslab_size, errno);
387 }
388}
389
7bbbc3c0
NC
390void
391Perl_Slab_to_rw(pTHX_ OPSLAB *const slab)
3107b51f 392{
3107b51f
FC
393 OPSLAB *slab2;
394
395 PERL_ARGS_ASSERT_SLAB_TO_RW;
396
3107b51f
FC
397 if (!slab->opslab_readonly) return;
398 slab2 = slab;
399 for (; slab2; slab2 = slab2->opslab_next) {
400 /*DEBUG_U(PerlIO_printf(Perl_debug_log,"mprotect ->rw %lu at %p\n",
401 (unsigned long) size, slab2));*/
402 if (mprotect((void *)slab2, slab2->opslab_size * sizeof(I32 *),
403 PROT_READ|PROT_WRITE)) {
404 Perl_warn(aTHX_ "mprotect RW for %p %lu failed with %d", slab,
405 (unsigned long)slab2->opslab_size, errno);
406 }
407 }
408 slab->opslab_readonly = 0;
409}
410
411#else
9e4d7a13 412# define Slab_to_rw(op) NOOP
3107b51f
FC
413#endif
414
8be227ab
FC
415/* This cannot possibly be right, but it was copied from the old slab
416 allocator, to which it was originally added, without explanation, in
417 commit 083fcd5. */
7aef8e5b 418#ifdef NETWARE
8be227ab 419# define PerlMemShared PerlMem
7aef8e5b 420#endif
8be227ab 421
c5cd8dab
DM
422/* make freed ops die if they're inadvertently executed */
423#ifdef DEBUGGING
424static OP *
425S_pp_freed(pTHX)
426{
427 DIE(aTHX_ "panic: freed op 0x%p called\n", PL_op);
428}
429#endif
430
8be227ab
FC
431void
432Perl_Slab_Free(pTHX_ void *op)
433{
434 OP * const o = (OP *)op;
435 OPSLAB *slab;
436
437 PERL_ARGS_ASSERT_SLAB_FREE;
438
c5cd8dab
DM
439#ifdef DEBUGGING
440 o->op_ppaddr = S_pp_freed;
441#endif
442
8be227ab 443 if (!o->op_slabbed) {
90840c5d
RU
444 if (!o->op_static)
445 PerlMemShared_free(op);
8be227ab
FC
446 return;
447 }
448
449 slab = OpSLAB(o);
450 /* If this op is already freed, our refcount will get screwy. */
451 assert(o->op_type != OP_FREED);
452 o->op_type = OP_FREED;
453 o->op_next = slab->opslab_freed;
454 slab->opslab_freed = o;
eb212a1c 455 DEBUG_S_warn((aTHX_ "free op at %p, recorded in slab %p", (void*)o, (void*)slab));
8be227ab
FC
456 OpslabREFCNT_dec_padok(slab);
457}
458
459void
460Perl_opslab_free_nopad(pTHX_ OPSLAB *slab)
461{
8be227ab
FC
462 const bool havepad = !!PL_comppad;
463 PERL_ARGS_ASSERT_OPSLAB_FREE_NOPAD;
464 if (havepad) {
465 ENTER;
466 PAD_SAVE_SETNULLPAD();
467 }
468 opslab_free(slab);
469 if (havepad) LEAVE;
470}
471
472void
473Perl_opslab_free(pTHX_ OPSLAB *slab)
474{
475 OPSLAB *slab2;
476 PERL_ARGS_ASSERT_OPSLAB_FREE;
81611534 477 PERL_UNUSED_CONTEXT;
eb212a1c 478 DEBUG_S_warn((aTHX_ "freeing slab %p", (void*)slab));
8be227ab 479 assert(slab->opslab_refcnt == 1);
3dc78631 480 do {
8be227ab 481 slab2 = slab->opslab_next;
7aef8e5b 482#ifdef DEBUGGING
8be227ab 483 slab->opslab_refcnt = ~(size_t)0;
7aef8e5b
FC
484#endif
485#ifdef PERL_DEBUG_READONLY_OPS
3107b51f 486 DEBUG_m(PerlIO_printf(Perl_debug_log, "Deallocate slab at %p\n",
eb212a1c 487 (void*)slab));
3107b51f
FC
488 if (munmap(slab, slab->opslab_size * sizeof(I32 *))) {
489 perror("munmap failed");
490 abort();
491 }
7aef8e5b 492#else
8be227ab 493 PerlMemShared_free(slab);
7aef8e5b 494#endif
3dc78631
DM
495 slab = slab2;
496 } while (slab);
8be227ab
FC
497}
498
499void
500Perl_opslab_force_free(pTHX_ OPSLAB *slab)
501{
502 OPSLAB *slab2;
7aef8e5b 503#ifdef DEBUGGING
8be227ab 504 size_t savestack_count = 0;
7aef8e5b 505#endif
8be227ab
FC
506 PERL_ARGS_ASSERT_OPSLAB_FORCE_FREE;
507 slab2 = slab;
508 do {
19742f39 509 OPSLOT *slot;
8be227ab
FC
510 for (slot = slab2->opslab_first;
511 slot->opslot_next;
512 slot = slot->opslot_next) {
513 if (slot->opslot_op.op_type != OP_FREED
514 && !(slot->opslot_op.op_savefree
7aef8e5b 515#ifdef DEBUGGING
8be227ab 516 && ++savestack_count
7aef8e5b 517#endif
8be227ab
FC
518 )
519 ) {
520 assert(slot->opslot_op.op_slabbed);
8be227ab 521 op_free(&slot->opslot_op);
3bf28c7e 522 if (slab->opslab_refcnt == 1) goto free;
8be227ab
FC
523 }
524 }
525 } while ((slab2 = slab2->opslab_next));
526 /* > 1 because the CV still holds a reference count. */
527 if (slab->opslab_refcnt > 1) { /* still referenced by the savestack */
7aef8e5b 528#ifdef DEBUGGING
8be227ab 529 assert(savestack_count == slab->opslab_refcnt-1);
7aef8e5b 530#endif
ee5ee853
FC
531 /* Remove the CV’s reference count. */
532 slab->opslab_refcnt--;
8be227ab
FC
533 return;
534 }
535 free:
536 opslab_free(slab);
537}
538
3107b51f
FC
539#ifdef PERL_DEBUG_READONLY_OPS
540OP *
541Perl_op_refcnt_inc(pTHX_ OP *o)
542{
543 if(o) {
372eab01
NC
544 OPSLAB *const slab = o->op_slabbed ? OpSLAB(o) : NULL;
545 if (slab && slab->opslab_readonly) {
83519873 546 Slab_to_rw(slab);
372eab01
NC
547 ++o->op_targ;
548 Slab_to_ro(slab);
549 } else {
550 ++o->op_targ;
551 }
3107b51f
FC
552 }
553 return o;
554
555}
556
557PADOFFSET
558Perl_op_refcnt_dec(pTHX_ OP *o)
559{
372eab01
NC
560 PADOFFSET result;
561 OPSLAB *const slab = o->op_slabbed ? OpSLAB(o) : NULL;
562
3107b51f 563 PERL_ARGS_ASSERT_OP_REFCNT_DEC;
372eab01
NC
564
565 if (slab && slab->opslab_readonly) {
83519873 566 Slab_to_rw(slab);
372eab01
NC
567 result = --o->op_targ;
568 Slab_to_ro(slab);
569 } else {
570 result = --o->op_targ;
571 }
572 return result;
3107b51f
FC
573}
574#endif
e50aee73 575/*
ce6f1cbc 576 * In the following definition, the ", (OP*)0" is just to make the compiler
a5f75d66 577 * think the expression is of the right type: croak actually does a Siglongjmp.
e50aee73 578 */
11343788 579#define CHECKOP(type,o) \
ce6f1cbc 580 ((PL_op_mask && PL_op_mask[type]) \
5dc0d613 581 ? ( op_free((OP*)o), \
cb77fdf0 582 Perl_croak(aTHX_ "'%s' trapped by operation mask", PL_op_desc[type]), \
ce6f1cbc 583 (OP*)0 ) \
16c91539 584 : PL_check[type](aTHX_ (OP*)o))
e50aee73 585
e6438c1a 586#define RETURN_UNLIMITED_NUMBER (PERL_INT_MAX / 2)
c53d7c7d 587
b9a07097 588#define OpTYPE_set(o,type) \
cba5a3b0
DG
589 STMT_START { \
590 o->op_type = (OPCODE)type; \
591 o->op_ppaddr = PL_ppaddr[type]; \
592 } STMT_END
593
76e3520e 594STATIC OP *
cea2e8a9 595S_no_fh_allowed(pTHX_ OP *o)
79072805 596{
7918f24d
NC
597 PERL_ARGS_ASSERT_NO_FH_ALLOWED;
598
cea2e8a9 599 yyerror(Perl_form(aTHX_ "Missing comma after first argument to %s function",
53e06cf0 600 OP_DESC(o)));
11343788 601 return o;
79072805
LW
602}
603
76e3520e 604STATIC OP *
ce16c625
BF
605S_too_few_arguments_pv(pTHX_ OP *o, const char* name, U32 flags)
606{
607 PERL_ARGS_ASSERT_TOO_FEW_ARGUMENTS_PV;
608 yyerror_pv(Perl_form(aTHX_ "Not enough arguments for %s", name), flags);
609 return o;
610}
611
612STATIC OP *
613S_too_many_arguments_pv(pTHX_ OP *o, const char *name, U32 flags)
614{
615 PERL_ARGS_ASSERT_TOO_MANY_ARGUMENTS_PV;
7918f24d 616
ce16c625 617 yyerror_pv(Perl_form(aTHX_ "Too many arguments for %s", name), flags);
11343788 618 return o;
79072805
LW
619}
620
76e3520e 621STATIC void
ed9feedd 622S_bad_type_pv(pTHX_ I32 n, const char *t, const OP *o, const OP *kid)
8990e307 623{
ce16c625
BF
624 PERL_ARGS_ASSERT_BAD_TYPE_PV;
625
626 yyerror_pv(Perl_form(aTHX_ "Type of arg %d to %s must be %s (not %s)",
ed9feedd 627 (int)n, PL_op_desc[(o)->op_type], t, OP_DESC(kid)), 0);
ce16c625 628}
7918f24d 629
ed9feedd
DD
630/* remove flags var, its unused in all callers, move to to right end since gv
631 and kid are always the same */
ce16c625 632STATIC void
ed9feedd 633S_bad_type_gv(pTHX_ I32 n, GV *gv, const OP *kid, const char *t)
ce16c625 634{
ecf05a58 635 SV * const namesv = cv_name((CV *)gv, NULL, 0);
7b3b0904 636 PERL_ARGS_ASSERT_BAD_TYPE_GV;
ce16c625 637
147e3846 638 yyerror_pv(Perl_form(aTHX_ "Type of arg %d to %" SVf " must be %s (not %s)",
ed9feedd 639 (int)n, SVfARG(namesv), t, OP_DESC(kid)), SvUTF8(namesv));
8990e307
LW
640}
641
7a52d87a 642STATIC void
eb796c7f 643S_no_bareword_allowed(pTHX_ OP *o)
7a52d87a 644{
7918f24d
NC
645 PERL_ARGS_ASSERT_NO_BAREWORD_ALLOWED;
646
5a844595 647 qerror(Perl_mess(aTHX_
147e3846 648 "Bareword \"%" SVf "\" not allowed while \"strict subs\" in use",
be2597df 649 SVfARG(cSVOPo_sv)));
eb796c7f 650 o->op_private &= ~OPpCONST_STRICT; /* prevent warning twice about the same OP */
7a52d87a
GS
651}
652
79072805
LW
653/* "register" allocation */
654
655PADOFFSET
d6447115 656Perl_allocmy(pTHX_ const char *const name, const STRLEN len, const U32 flags)
93a17b20 657{
a0d0e21e 658 PADOFFSET off;
12bd6ede 659 const bool is_our = (PL_parser->in_my == KEY_our);
a0d0e21e 660
7918f24d
NC
661 PERL_ARGS_ASSERT_ALLOCMY;
662
48d0d1be 663 if (flags & ~SVf_UTF8)
d6447115
NC
664 Perl_croak(aTHX_ "panic: allocmy illegal flag bits 0x%" UVxf,
665 (UV)flags);
666
59f00321 667 /* complain about "my $<special_var>" etc etc */
7a207065
KW
668 if ( len
669 && !( is_our
670 || isALPHA(name[1])
671 || ( (flags & SVf_UTF8)
672 && isIDFIRST_utf8_safe((U8 *)name+1, name + len))
673 || (name[1] == '_' && len > 2)))
834a4ddd 674 {
b14845b4 675 if (!(flags & SVf_UTF8 && UTF8_IS_START(name[1]))
f6a1dc93 676 && isASCII(name[1])
b14845b4 677 && (!isPRINT(name[1]) || strchr("\t\n\r\f", name[1]))) {
8d9d0498 678 /* diag_listed_as: Can't use global %s in "%s" */
d6447115
NC
679 yyerror(Perl_form(aTHX_ "Can't use global %c^%c%.*s in \"%s\"",
680 name[0], toCTRL(name[1]), (int)(len - 2), name + 2,
aab6a793 681 PL_parser->in_my == KEY_state ? "state" : "my"));
d1544d85 682 } else {
ce16c625
BF
683 yyerror_pv(Perl_form(aTHX_ "Can't use global %.*s in \"%s\"", (int) len, name,
684 PL_parser->in_my == KEY_state ? "state" : "my"), flags & SVf_UTF8);
46fc3d4c 685 }
a0d0e21e 686 }
748a9306 687
dd2155a4 688 /* allocate a spare slot and store the name in that slot */
93a17b20 689
cc76b5cc 690 off = pad_add_name_pvn(name, len,
48d0d1be 691 (is_our ? padadd_OUR :
2502ffdf 692 PL_parser->in_my == KEY_state ? padadd_STATE : 0),
12bd6ede 693 PL_parser->in_my_stash,
3edf23ff 694 (is_our
133706a6 695 /* $_ is always in main::, even with our */
ef00320b
FC
696 ? (PL_curstash && !memEQs(name,len,"$_")
697 ? PL_curstash
698 : PL_defstash)
5c284bb0 699 : NULL
cca43f78 700 )
dd2155a4 701 );
a74073ad
DM
702 /* anon sub prototypes contains state vars should always be cloned,
703 * otherwise the state var would be shared between anon subs */
704
705 if (PL_parser->in_my == KEY_state && CvANON(PL_compcv))
706 CvCLONE_on(PL_compcv);
707
dd2155a4 708 return off;
79072805
LW
709}
710
c0b8aebd 711/*
dcccc8ff
KW
712=head1 Optree Manipulation Functions
713
c0b8aebd
FC
714=for apidoc alloccopstash
715
716Available only under threaded builds, this function allocates an entry in
717C<PL_stashpad> for the stash passed to it.
718
719=cut
720*/
721
d4d03940
FC
722#ifdef USE_ITHREADS
723PADOFFSET
1dc74fdb 724Perl_alloccopstash(pTHX_ HV *hv)
d4d03940
FC
725{
726 PADOFFSET off = 0, o = 1;
727 bool found_slot = FALSE;
728
1dc74fdb
FC
729 PERL_ARGS_ASSERT_ALLOCCOPSTASH;
730
731 if (PL_stashpad[PL_stashpadix] == hv) return PL_stashpadix;
d4d03940 732
1dc74fdb
FC
733 for (; o < PL_stashpadmax; ++o) {
734 if (PL_stashpad[o] == hv) return PL_stashpadix = o;
735 if (!PL_stashpad[o] || SvTYPE(PL_stashpad[o]) != SVt_PVHV)
d4d03940
FC
736 found_slot = TRUE, off = o;
737 }
738 if (!found_slot) {
1dc74fdb
FC
739 Renew(PL_stashpad, PL_stashpadmax + 10, HV *);
740 Zero(PL_stashpad + PL_stashpadmax, 10, HV *);
741 off = PL_stashpadmax;
742 PL_stashpadmax += 10;
d4d03940
FC
743 }
744
1dc74fdb 745 PL_stashpad[PL_stashpadix = off] = hv;
d4d03940
FC
746 return off;
747}
748#endif
749
d2c837a0
DM
750/* free the body of an op without examining its contents.
751 * Always use this rather than FreeOp directly */
752
4136a0f7 753static void
d2c837a0
DM
754S_op_destroy(pTHX_ OP *o)
755{
d2c837a0
DM
756 FreeOp(o);
757}
758
79072805
LW
759/* Destructor */
760
6e53b6ca
DD
761/*
762=for apidoc Am|void|op_free|OP *o
763
cc41839b
FC
764Free an op. Only use this when an op is no longer linked to from any
765optree.
6e53b6ca
DD
766
767=cut
768*/
769
79072805 770void
864dbfa3 771Perl_op_free(pTHX_ OP *o)
79072805 772{
27da23d5 773 dVAR;
acb36ea4 774 OPCODE type;
0997db6f
TC
775 SSize_t defer_ix = -1;
776 SSize_t defer_stack_alloc = 0;
777 OP **defer_stack = NULL;
79072805 778
0997db6f 779 do {
79072805 780
0997db6f
TC
781 /* Though ops may be freed twice, freeing the op after its slab is a
782 big no-no. */
783 assert(!o || !o->op_slabbed || OpSLAB(o)->opslab_refcnt != ~(size_t)0);
784 /* During the forced freeing of ops after compilation failure, kidops
785 may be freed before their parents. */
786 if (!o || o->op_type == OP_FREED)
787 continue;
d0c8136d 788
0997db6f 789 type = o->op_type;
d0c8136d 790
0997db6f 791 /* an op should only ever acquire op_private flags that we know about.
09681a13
DM
792 * If this fails, you may need to fix something in regen/op_private.
793 * Don't bother testing if:
794 * * the op_ppaddr doesn't match the op; someone may have
795 * overridden the op and be doing strange things with it;
796 * * we've errored, as op flags are often left in an
797 * inconsistent state then. Note that an error when
798 * compiling the main program leaves PL_parser NULL, so
ad53d4d4 799 * we can't spot faults in the main code, only
09681a13
DM
800 * evaled/required code */
801#ifdef DEBUGGING
802 if ( o->op_ppaddr == PL_ppaddr[o->op_type]
803 && PL_parser
804 && !PL_parser->error_count)
805 {
0997db6f
TC
806 assert(!(o->op_private & ~PL_op_private_valid[type]));
807 }
09681a13 808#endif
7934575e 809
0997db6f
TC
810 if (o->op_private & OPpREFCOUNTED) {
811 switch (type) {
812 case OP_LEAVESUB:
813 case OP_LEAVESUBLV:
814 case OP_LEAVEEVAL:
815 case OP_LEAVE:
816 case OP_SCOPE:
817 case OP_LEAVEWRITE:
818 {
819 PADOFFSET refcnt;
820 OP_REFCNT_LOCK;
821 refcnt = OpREFCNT_dec(o);
822 OP_REFCNT_UNLOCK;
823 if (refcnt) {
824 /* Need to find and remove any pattern match ops from the list
825 we maintain for reset(). */
826 find_and_forget_pmops(o);
827 continue;
828 }
829 }
830 break;
831 default:
832 break;
833 }
834 }
f37b8c3f 835
0997db6f
TC
836 /* Call the op_free hook if it has been set. Do it now so that it's called
837 * at the right time for refcounted ops, but still before all of the kids
838 * are freed. */
839 CALL_OPFREEHOOK(o);
840
841 if (o->op_flags & OPf_KIDS) {
842 OP *kid, *nextkid;
843 for (kid = cUNOPo->op_first; kid; kid = nextkid) {
e6dae479 844 nextkid = OpSIBLING(kid); /* Get before next freeing kid */
0997db6f
TC
845 if (!kid || kid->op_type == OP_FREED)
846 /* During the forced freeing of ops after
847 compilation failure, kidops may be freed before
848 their parents. */
849 continue;
850 if (!(kid->op_flags & OPf_KIDS))
851 /* If it has no kids, just free it now */
852 op_free(kid);
853 else
aa9d1253 854 DEFER_OP(kid);
0997db6f
TC
855 }
856 }
857 if (type == OP_NULL)
858 type = (OPCODE)o->op_targ;
acb36ea4 859
0997db6f
TC
860 if (o->op_slabbed)
861 Slab_to_rw(OpSLAB(o));
fc97af9c 862
0997db6f
TC
863 /* COP* is not cleared by op_clear() so that we may track line
864 * numbers etc even after null() */
865 if (type == OP_NEXTSTATE || type == OP_DBSTATE) {
866 cop_free((COP*)o);
867 }
acb36ea4 868
0997db6f
TC
869 op_clear(o);
870 FreeOp(o);
0997db6f
TC
871 if (PL_op == o)
872 PL_op = NULL;
aa9d1253 873 } while ( (o = POP_DEFERRED_OP()) );
0997db6f
TC
874
875 Safefree(defer_stack);
acb36ea4 876}
79072805 877
ab576797
DM
878/* S_op_clear_gv(): free a GV attached to an OP */
879
f9db5646 880STATIC
ab576797
DM
881#ifdef USE_ITHREADS
882void S_op_clear_gv(pTHX_ OP *o, PADOFFSET *ixp)
883#else
884void S_op_clear_gv(pTHX_ OP *o, SV**svp)
885#endif
886{
887
fedf30e1
DM
888 GV *gv = (o->op_type == OP_GV || o->op_type == OP_GVSV
889 || o->op_type == OP_MULTIDEREF)
ab576797
DM
890#ifdef USE_ITHREADS
891 && PL_curpad
892 ? ((GV*)PAD_SVl(*ixp)) : NULL;
893#else
894 ? (GV*)(*svp) : NULL;
895#endif
896 /* It's possible during global destruction that the GV is freed
897 before the optree. Whilst the SvREFCNT_inc is happy to bump from
898 0 to 1 on a freed SV, the corresponding SvREFCNT_dec from 1 to 0
899 will trigger an assertion failure, because the entry to sv_clear
900 checks that the scalar is not already freed. A check of for
901 !SvIS_FREED(gv) turns out to be invalid, because during global
902 destruction the reference count can be forced down to zero
903 (with SVf_BREAK set). In which case raising to 1 and then
904 dropping to 0 triggers cleanup before it should happen. I
905 *think* that this might actually be a general, systematic,
906 weakness of the whole idea of SVf_BREAK, in that code *is*
907 allowed to raise and lower references during global destruction,
908 so any *valid* code that happens to do this during global
909 destruction might well trigger premature cleanup. */
910 bool still_valid = gv && SvREFCNT(gv);
911
912 if (still_valid)
913 SvREFCNT_inc_simple_void(gv);
914#ifdef USE_ITHREADS
915 if (*ixp > 0) {
916 pad_swipe(*ixp, TRUE);
917 *ixp = 0;
918 }
919#else
920 SvREFCNT_dec(*svp);
921 *svp = NULL;
922#endif
923 if (still_valid) {
924 int try_downgrade = SvREFCNT(gv) == 2;
925 SvREFCNT_dec_NN(gv);
926 if (try_downgrade)
927 gv_try_downgrade(gv);
928 }
929}
930
931
93c66552
DM
932void
933Perl_op_clear(pTHX_ OP *o)
acb36ea4 934{
13137afc 935
27da23d5 936 dVAR;
7918f24d
NC
937
938 PERL_ARGS_ASSERT_OP_CLEAR;
939
11343788 940 switch (o->op_type) {
acb36ea4 941 case OP_NULL: /* Was holding old type, if any. */
c67159e1 942 /* FALLTHROUGH */
4d193d44 943 case OP_ENTERTRY:
acb36ea4 944 case OP_ENTEREVAL: /* Was holding hints. */
4fa06845 945 case OP_ARGDEFELEM: /* Was holding signature index. */
acb36ea4 946 o->op_targ = 0;
a0d0e21e 947 break;
a6006777 948 default:
ac4c12e7 949 if (!(o->op_flags & OPf_REF)
ef69c8fc 950 || (PL_check[o->op_type] != Perl_ck_ftst))
a6006777 951 break;
924ba076 952 /* FALLTHROUGH */
463ee0b2 953 case OP_GVSV:
79072805 954 case OP_GV:
a6006777 955 case OP_AELEMFAST:
f7461760 956#ifdef USE_ITHREADS
ab576797 957 S_op_clear_gv(aTHX_ o, &(cPADOPx(o)->op_padix));
350de78d 958#else
ab576797 959 S_op_clear_gv(aTHX_ o, &(cSVOPx(o)->op_sv));
350de78d 960#endif
79072805 961 break;
810bd8b7 962 case OP_METHOD_REDIR:
963 case OP_METHOD_REDIR_SUPER:
964#ifdef USE_ITHREADS
965 if (cMETHOPx(o)->op_rclass_targ) {
966 pad_swipe(cMETHOPx(o)->op_rclass_targ, 1);
967 cMETHOPx(o)->op_rclass_targ = 0;
968 }
969#else
970 SvREFCNT_dec(cMETHOPx(o)->op_rclass_sv);
971 cMETHOPx(o)->op_rclass_sv = NULL;
972#endif
2165bd23 973 /* FALLTHROUGH */
a1ae71d2 974 case OP_METHOD_NAMED:
7d6c333c 975 case OP_METHOD_SUPER:
b46e009d 976 SvREFCNT_dec(cMETHOPx(o)->op_u.op_meth_sv);
977 cMETHOPx(o)->op_u.op_meth_sv = NULL;
978#ifdef USE_ITHREADS
979 if (o->op_targ) {
980 pad_swipe(o->op_targ, 1);
981 o->op_targ = 0;
982 }
983#endif
984 break;
79072805 985 case OP_CONST:
996c9baa 986 case OP_HINTSEVAL:
11343788 987 SvREFCNT_dec(cSVOPo->op_sv);
a0714e2c 988 cSVOPo->op_sv = NULL;
3b1c21fa
AB
989#ifdef USE_ITHREADS
990 /** Bug #15654
991 Even if op_clear does a pad_free for the target of the op,
6a077020 992 pad_free doesn't actually remove the sv that exists in the pad;
3b1c21fa
AB
993 instead it lives on. This results in that it could be reused as
994 a target later on when the pad was reallocated.
995 **/
996 if(o->op_targ) {
997 pad_swipe(o->op_targ,1);
998 o->op_targ = 0;
999 }
1000#endif
79072805 1001 break;
c9df4fda 1002 case OP_DUMP:
748a9306
LW
1003 case OP_GOTO:
1004 case OP_NEXT:
1005 case OP_LAST:
1006 case OP_REDO:
11343788 1007 if (o->op_flags & (OPf_SPECIAL|OPf_STACKED|OPf_KIDS))
748a9306 1008 break;
924ba076 1009 /* FALLTHROUGH */
a0d0e21e 1010 case OP_TRANS:
bb16bae8 1011 case OP_TRANSR:
abd07ec0
DM
1012 if ( (o->op_type == OP_TRANS || o->op_type == OP_TRANSR)
1013 && (o->op_private & (OPpTRANS_FROM_UTF|OPpTRANS_TO_UTF)))
1014 {
043e41b8
DM
1015#ifdef USE_ITHREADS
1016 if (cPADOPo->op_padix > 0) {
1017 pad_swipe(cPADOPo->op_padix, TRUE);
1018 cPADOPo->op_padix = 0;
1019 }
1020#else
a0ed51b3 1021 SvREFCNT_dec(cSVOPo->op_sv);
a0714e2c 1022 cSVOPo->op_sv = NULL;
043e41b8 1023#endif
acb36ea4
GS
1024 }
1025 else {
ea71c68d 1026 PerlMemShared_free(cPVOPo->op_pv);
bd61b366 1027 cPVOPo->op_pv = NULL;
acb36ea4 1028 }
a0d0e21e
LW
1029 break;
1030 case OP_SUBST:
20e98b0f 1031 op_free(cPMOPo->op_pmreplrootu.op_pmreplroot);
971a9dd3 1032 goto clear_pmop;
5012eebe
DM
1033
1034 case OP_SPLIT:
692044df
DM
1035 if ( (o->op_private & OPpSPLIT_ASSIGN) /* @array = split */
1036 && !(o->op_flags & OPf_STACKED)) /* @{expr} = split */
5012eebe
DM
1037 {
1038 if (o->op_private & OPpSPLIT_LEX)
1039 pad_free(cPMOPo->op_pmreplrootu.op_pmtargetoff);
1040 else
971a9dd3 1041#ifdef USE_ITHREADS
5012eebe 1042 pad_swipe(cPMOPo->op_pmreplrootu.op_pmtargetoff, TRUE);
971a9dd3 1043#else
5012eebe 1044 SvREFCNT_dec(MUTABLE_SV(cPMOPo->op_pmreplrootu.op_pmtargetgv));
971a9dd3 1045#endif
5012eebe 1046 }
924ba076 1047 /* FALLTHROUGH */
a0d0e21e 1048 case OP_MATCH:
8782bef2 1049 case OP_QR:
7b52d656 1050 clear_pmop:
867940b8
DM
1051 if (!(cPMOPo->op_pmflags & PMf_CODELIST_PRIVATE))
1052 op_free(cPMOPo->op_code_list);
68e2671b 1053 cPMOPo->op_code_list = NULL;
23083432 1054 forget_pmop(cPMOPo);
20e98b0f 1055 cPMOPo->op_pmreplrootu.op_pmreplroot = NULL;
9cddf794
NC
1056 /* we use the same protection as the "SAFE" version of the PM_ macros
1057 * here since sv_clean_all might release some PMOPs
5f8cb046
DM
1058 * after PL_regex_padav has been cleared
1059 * and the clearing of PL_regex_padav needs to
1060 * happen before sv_clean_all
1061 */
13137afc
AB
1062#ifdef USE_ITHREADS
1063 if(PL_regex_pad) { /* We could be in destruction */
402d2eb1 1064 const IV offset = (cPMOPo)->op_pmoffset;
9cddf794 1065 ReREFCNT_dec(PM_GETRE(cPMOPo));
402d2eb1
NC
1066 PL_regex_pad[offset] = &PL_sv_undef;
1067 sv_catpvn_nomg(PL_regex_pad[0], (const char *)&offset,
1068 sizeof(offset));
13137afc 1069 }
9cddf794
NC
1070#else
1071 ReREFCNT_dec(PM_GETRE(cPMOPo));
1072 PM_SETRE(cPMOPo, NULL);
1eb1540c 1073#endif
13137afc 1074
a0d0e21e 1075 break;
fedf30e1 1076
4fa06845
DM
1077 case OP_ARGCHECK:
1078 PerlMemShared_free(cUNOP_AUXo->op_aux);
1079 break;
1080
e839e6ed
DM
1081 case OP_MULTICONCAT:
1082 {
1083 UNOP_AUX_item *aux = cUNOP_AUXo->op_aux;
1084 /* aux[PERL_MULTICONCAT_IX_PLAIN_PV] and/or
1085 * aux[PERL_MULTICONCAT_IX_UTF8_PV] point to plain and/or
1086 * utf8 shared strings */
1087 char *p1 = aux[PERL_MULTICONCAT_IX_PLAIN_PV].pv;
1088 char *p2 = aux[PERL_MULTICONCAT_IX_UTF8_PV].pv;
1089 if (p1)
1090 PerlMemShared_free(p1);
1091 if (p2 && p1 != p2)
1092 PerlMemShared_free(p2);
1093 PerlMemShared_free(aux);
1094 }
1095 break;
1096
fedf30e1
DM
1097 case OP_MULTIDEREF:
1098 {
1099 UNOP_AUX_item *items = cUNOP_AUXo->op_aux;
1100 UV actions = items->uv;
1101 bool last = 0;
1102 bool is_hash = FALSE;
1103
1104 while (!last) {
1105 switch (actions & MDEREF_ACTION_MASK) {
1106
1107 case MDEREF_reload:
1108 actions = (++items)->uv;
1109 continue;
1110
1111 case MDEREF_HV_padhv_helem:
1112 is_hash = TRUE;
2165bd23 1113 /* FALLTHROUGH */
fedf30e1
DM
1114 case MDEREF_AV_padav_aelem:
1115 pad_free((++items)->pad_offset);
1116 goto do_elem;
1117
1118 case MDEREF_HV_gvhv_helem:
1119 is_hash = TRUE;
2165bd23 1120 /* FALLTHROUGH */
fedf30e1
DM
1121 case MDEREF_AV_gvav_aelem:
1122#ifdef USE_ITHREADS
1123 S_op_clear_gv(aTHX_ o, &((++items)->pad_offset));
1124#else
1125 S_op_clear_gv(aTHX_ o, &((++items)->sv));
1126#endif
1127 goto do_elem;
1128
1129 case MDEREF_HV_gvsv_vivify_rv2hv_helem:
1130 is_hash = TRUE;
2165bd23 1131 /* FALLTHROUGH */
fedf30e1
DM
1132 case MDEREF_AV_gvsv_vivify_rv2av_aelem:
1133#ifdef USE_ITHREADS
1134 S_op_clear_gv(aTHX_ o, &((++items)->pad_offset));
1135#else
1136 S_op_clear_gv(aTHX_ o, &((++items)->sv));
1137#endif
1138 goto do_vivify_rv2xv_elem;
1139
1140 case MDEREF_HV_padsv_vivify_rv2hv_helem:
1141 is_hash = TRUE;
2165bd23 1142 /* FALLTHROUGH */
fedf30e1
DM
1143 case MDEREF_AV_padsv_vivify_rv2av_aelem:
1144 pad_free((++items)->pad_offset);
1145 goto do_vivify_rv2xv_elem;
1146
1147 case MDEREF_HV_pop_rv2hv_helem:
1148 case MDEREF_HV_vivify_rv2hv_helem:
1149 is_hash = TRUE;
2165bd23 1150 /* FALLTHROUGH */
fedf30e1
DM
1151 do_vivify_rv2xv_elem:
1152 case MDEREF_AV_pop_rv2av_aelem:
1153 case MDEREF_AV_vivify_rv2av_aelem:
1154 do_elem:
1155 switch (actions & MDEREF_INDEX_MASK) {
1156 case MDEREF_INDEX_none:
1157 last = 1;
1158 break;
1159 case MDEREF_INDEX_const:
1160 if (is_hash) {
1161#ifdef USE_ITHREADS
1162 /* see RT #15654 */
1163 pad_swipe((++items)->pad_offset, 1);
1164#else
1165 SvREFCNT_dec((++items)->sv);
1166#endif
1167 }
1168 else
1169 items++;
1170 break;
1171 case MDEREF_INDEX_padsv:
1172 pad_free((++items)->pad_offset);
1173 break;
1174 case MDEREF_INDEX_gvsv:
1175#ifdef USE_ITHREADS
1176 S_op_clear_gv(aTHX_ o, &((++items)->pad_offset));
1177#else
1178 S_op_clear_gv(aTHX_ o, &((++items)->sv));
1179#endif
1180 break;
1181 }
1182
1183 if (actions & MDEREF_FLAG_last)
1184 last = 1;
1185 is_hash = FALSE;
1186
1187 break;
1188
1189 default:
1190 assert(0);
1191 last = 1;
1192 break;
1193
1194 } /* switch */
1195
1196 actions >>= MDEREF_SHIFT;
1197 } /* while */
1198
1199 /* start of malloc is at op_aux[-1], where the length is
1200 * stored */
1201 PerlMemShared_free(cUNOP_AUXo->op_aux - 1);
1202 }
1203 break;
79072805
LW
1204 }
1205
743e66e6 1206 if (o->op_targ > 0) {
11343788 1207 pad_free(o->op_targ);
743e66e6
GS
1208 o->op_targ = 0;
1209 }
79072805
LW
1210}
1211
76e3520e 1212STATIC void
3eb57f73
HS
1213S_cop_free(pTHX_ COP* cop)
1214{
7918f24d
NC
1215 PERL_ARGS_ASSERT_COP_FREE;
1216
05ec9bb3 1217 CopFILE_free(cop);
0453d815 1218 if (! specialWARN(cop->cop_warnings))
72dc9ed5 1219 PerlMemShared_free(cop->cop_warnings);
20439bc7 1220 cophh_free(CopHINTHASH_get(cop));
515abc43
FC
1221 if (PL_curcop == cop)
1222 PL_curcop = NULL;
3eb57f73
HS
1223}
1224
c2b1997a 1225STATIC void
c4bd3ae5 1226S_forget_pmop(pTHX_ PMOP *const o
c4bd3ae5 1227 )
c2b1997a
NC
1228{
1229 HV * const pmstash = PmopSTASH(o);
7918f24d
NC
1230
1231 PERL_ARGS_ASSERT_FORGET_PMOP;
1232
e39a6381 1233 if (pmstash && !SvIS_FREED(pmstash) && SvMAGICAL(pmstash)) {
ad64d0ec 1234 MAGIC * const mg = mg_find((const SV *)pmstash, PERL_MAGIC_symtab);
c2b1997a
NC
1235 if (mg) {
1236 PMOP **const array = (PMOP**) mg->mg_ptr;
1237 U32 count = mg->mg_len / sizeof(PMOP**);
1238 U32 i = count;
1239
1240 while (i--) {
1241 if (array[i] == o) {
1242 /* Found it. Move the entry at the end to overwrite it. */
1243 array[i] = array[--count];
1244 mg->mg_len = count * sizeof(PMOP**);
1245 /* Could realloc smaller at this point always, but probably
1246 not worth it. Probably worth free()ing if we're the
1247 last. */
1248 if(!count) {
1249 Safefree(mg->mg_ptr);
1250 mg->mg_ptr = NULL;
1251 }
1252 break;
1253 }
1254 }
1255 }
1256 }
1cdf7faf
NC
1257 if (PL_curpm == o)
1258 PL_curpm = NULL;
c2b1997a
NC
1259}
1260
bfd0ff22
NC
1261STATIC void
1262S_find_and_forget_pmops(pTHX_ OP *o)
1263{
7918f24d
NC
1264 PERL_ARGS_ASSERT_FIND_AND_FORGET_PMOPS;
1265
bfd0ff22
NC
1266 if (o->op_flags & OPf_KIDS) {
1267 OP *kid = cUNOPo->op_first;
1268 while (kid) {
1269 switch (kid->op_type) {
1270 case OP_SUBST:
5012eebe 1271 case OP_SPLIT:
bfd0ff22
NC
1272 case OP_MATCH:
1273 case OP_QR:
23083432 1274 forget_pmop((PMOP*)kid);
bfd0ff22
NC
1275 }
1276 find_and_forget_pmops(kid);
e6dae479 1277 kid = OpSIBLING(kid);
bfd0ff22
NC
1278 }
1279 }
1280}
1281
6e53b6ca
DD
1282/*
1283=for apidoc Am|void|op_null|OP *o
1284
1285Neutralizes an op when it is no longer needed, but is still linked to from
1286other ops.
1287
1288=cut
1289*/
1290
93c66552
DM
1291void
1292Perl_op_null(pTHX_ OP *o)
8990e307 1293{
27da23d5 1294 dVAR;
7918f24d
NC
1295
1296 PERL_ARGS_ASSERT_OP_NULL;
1297
acb36ea4
GS
1298 if (o->op_type == OP_NULL)
1299 return;
b5bbe64a 1300 op_clear(o);
11343788 1301 o->op_targ = o->op_type;
b9a07097 1302 OpTYPE_set(o, OP_NULL);
8990e307
LW
1303}
1304
4026c95a
SH
1305void
1306Perl_op_refcnt_lock(pTHX)
e1fc825d 1307 PERL_TSA_ACQUIRE(PL_op_mutex)
4026c95a 1308{
20b7effb 1309#ifdef USE_ITHREADS
27da23d5 1310 dVAR;
20b7effb 1311#endif
96a5add6 1312 PERL_UNUSED_CONTEXT;
4026c95a
SH
1313 OP_REFCNT_LOCK;
1314}
1315
1316void
1317Perl_op_refcnt_unlock(pTHX)
e1fc825d 1318 PERL_TSA_RELEASE(PL_op_mutex)
4026c95a 1319{
20b7effb 1320#ifdef USE_ITHREADS
27da23d5 1321 dVAR;
20b7effb 1322#endif
96a5add6 1323 PERL_UNUSED_CONTEXT;
4026c95a
SH
1324 OP_REFCNT_UNLOCK;
1325}
1326
3253bf85
DM
1327
1328/*
1329=for apidoc op_sibling_splice
1330
1331A general function for editing the structure of an existing chain of
796b6530 1332op_sibling nodes. By analogy with the perl-level C<splice()> function, allows
3253bf85
DM
1333you to delete zero or more sequential nodes, replacing them with zero or
1334more different nodes. Performs the necessary op_first/op_last
29e61fd9 1335housekeeping on the parent node and op_sibling manipulation on the
7e234f81 1336children. The last deleted node will be marked as as the last node by
87b5a8b9 1337updating the op_sibling/op_sibparent or op_moresib field as appropriate.
3253bf85
DM
1338
1339Note that op_next is not manipulated, and nodes are not freed; that is the
7e234f81 1340responsibility of the caller. It also won't create a new list op for an
8ae26bff 1341empty list etc; use higher-level functions like op_append_elem() for that.
3253bf85 1342
796b6530 1343C<parent> is the parent node of the sibling chain. It may passed as C<NULL> if
3269ea41 1344the splicing doesn't affect the first or last op in the chain.
3253bf85 1345
796b6530 1346C<start> is the node preceding the first node to be spliced. Node(s)
7e234f81 1347following it will be deleted, and ops will be inserted after it. If it is
796b6530 1348C<NULL>, the first node onwards is deleted, and nodes are inserted at the
3253bf85
DM
1349beginning.
1350
796b6530 1351C<del_count> is the number of nodes to delete. If zero, no nodes are deleted.
3253bf85
DM
1352If -1 or greater than or equal to the number of remaining kids, all
1353remaining kids are deleted.
1354
796b6530
KW
1355C<insert> is the first of a chain of nodes to be inserted in place of the nodes.
1356If C<NULL>, no nodes are inserted.
3253bf85 1357
796b6530 1358The head of the chain of deleted ops is returned, or C<NULL> if no ops were
3253bf85
DM
1359deleted.
1360
1361For example:
1362
1363 action before after returns
1364 ------ ----- ----- -------
1365
1366 P P
8ae26bff
DM
1367 splice(P, A, 2, X-Y-Z) | | B-C
1368 A-B-C-D A-X-Y-Z-D
3253bf85
DM
1369
1370 P P
1371 splice(P, NULL, 1, X-Y) | | A
1372 A-B-C-D X-Y-B-C-D
1373
1374 P P
8ae26bff
DM
1375 splice(P, NULL, 3, NULL) | | A-B-C
1376 A-B-C-D D
3253bf85
DM
1377
1378 P P
1379 splice(P, B, 0, X-Y) | | NULL
1380 A-B-C-D A-B-X-Y-C-D
1381
5e24af7d
DM
1382
1383For lower-level direct manipulation of C<op_sibparent> and C<op_moresib>,
fbe13c60 1384see C<L</OpMORESIB_set>>, C<L</OpLASTSIB_set>>, C<L</OpMAYBESIB_set>>.
5e24af7d 1385
3253bf85
DM
1386=cut
1387*/
1388
1389OP *
8ae26bff 1390Perl_op_sibling_splice(OP *parent, OP *start, int del_count, OP* insert)
3253bf85 1391{
3269ea41 1392 OP *first;
3253bf85
DM
1393 OP *rest;
1394 OP *last_del = NULL;
1395 OP *last_ins = NULL;
1396
3269ea41
DM
1397 if (start)
1398 first = OpSIBLING(start);
1399 else if (!parent)
1400 goto no_parent;
1401 else
1402 first = cLISTOPx(parent)->op_first;
3253bf85
DM
1403
1404 assert(del_count >= -1);
1405
1406 if (del_count && first) {
1407 last_del = first;
e6dae479
FC
1408 while (--del_count && OpHAS_SIBLING(last_del))
1409 last_del = OpSIBLING(last_del);
1410 rest = OpSIBLING(last_del);
5e24af7d 1411 OpLASTSIB_set(last_del, NULL);
3253bf85
DM
1412 }
1413 else
1414 rest = first;
1415
1416 if (insert) {
1417 last_ins = insert;
e6dae479
FC
1418 while (OpHAS_SIBLING(last_ins))
1419 last_ins = OpSIBLING(last_ins);
5e24af7d 1420 OpMAYBESIB_set(last_ins, rest, NULL);
3253bf85
DM
1421 }
1422 else
1423 insert = rest;
1424
29e61fd9 1425 if (start) {
5e24af7d 1426 OpMAYBESIB_set(start, insert, NULL);
29e61fd9 1427 }
b3e29a8d 1428 else {
3269ea41
DM
1429 if (!parent)
1430 goto no_parent;
3253bf85 1431 cLISTOPx(parent)->op_first = insert;
b3e29a8d
DM
1432 if (insert)
1433 parent->op_flags |= OPf_KIDS;
1434 else
1435 parent->op_flags &= ~OPf_KIDS;
1436 }
3253bf85
DM
1437
1438 if (!rest) {
29e61fd9 1439 /* update op_last etc */
3269ea41 1440 U32 type;
29e61fd9 1441 OP *lastop;
3253bf85 1442
3269ea41
DM
1443 if (!parent)
1444 goto no_parent;
1445
05039abd
DM
1446 /* ought to use OP_CLASS(parent) here, but that can't handle
1447 * ex-foo OP_NULL ops. Also note that XopENTRYCUSTOM() can't
1448 * either */
3269ea41 1449 type = parent->op_type;
05039abd
DM
1450 if (type == OP_CUSTOM) {
1451 dTHX;
1452 type = XopENTRYCUSTOM(parent, xop_class);
1453 }
1454 else {
1455 if (type == OP_NULL)
1456 type = parent->op_targ;
1457 type = PL_opargs[type] & OA_CLASS_MASK;
1458 }
3253bf85 1459
29e61fd9 1460 lastop = last_ins ? last_ins : start ? start : NULL;
3253bf85
DM
1461 if ( type == OA_BINOP
1462 || type == OA_LISTOP
1463 || type == OA_PMOP
1464 || type == OA_LOOP
1465 )
29e61fd9
DM
1466 cLISTOPx(parent)->op_last = lastop;
1467
5e24af7d
DM
1468 if (lastop)
1469 OpLASTSIB_set(lastop, parent);
3253bf85
DM
1470 }
1471 return last_del ? first : NULL;
3269ea41
DM
1472
1473 no_parent:
1474 Perl_croak_nocontext("panic: op_sibling_splice(): NULL parent");
3253bf85
DM
1475}
1476
3269ea41 1477
1fafe688
DM
1478#ifdef PERL_OP_PARENT
1479
29e61fd9
DM
1480/*
1481=for apidoc op_parent
1482
796b6530 1483Returns the parent OP of C<o>, if it has a parent. Returns C<NULL> otherwise.
1fafe688 1484This function is only available on perls built with C<-DPERL_OP_PARENT>.
29e61fd9
DM
1485
1486=cut
1487*/
1488
1489OP *
8ae26bff 1490Perl_op_parent(OP *o)
29e61fd9
DM
1491{
1492 PERL_ARGS_ASSERT_OP_PARENT;
e6dae479
FC
1493 while (OpHAS_SIBLING(o))
1494 o = OpSIBLING(o);
86cd3a13 1495 return o->op_sibparent;
29e61fd9
DM
1496}
1497
1fafe688
DM
1498#endif
1499
3253bf85
DM
1500
1501/* replace the sibling following start with a new UNOP, which becomes
1502 * the parent of the original sibling; e.g.
1503 *
1504 * op_sibling_newUNOP(P, A, unop-args...)
1505 *
1506 * P P
1507 * | becomes |
1508 * A-B-C A-U-C
1509 * |
1510 * B
1511 *
1512 * where U is the new UNOP.
1513 *
1514 * parent and start args are the same as for op_sibling_splice();
1515 * type and flags args are as newUNOP().
1516 *
1517 * Returns the new UNOP.
1518 */
1519
f9db5646 1520STATIC OP *
3253bf85
DM
1521S_op_sibling_newUNOP(pTHX_ OP *parent, OP *start, I32 type, I32 flags)
1522{
1523 OP *kid, *newop;
1524
1525 kid = op_sibling_splice(parent, start, 1, NULL);
1526 newop = newUNOP(type, flags, kid);
1527 op_sibling_splice(parent, start, 0, newop);
1528 return newop;
1529}
1530
1531
1532/* lowest-level newLOGOP-style function - just allocates and populates
1533 * the struct. Higher-level stuff should be done by S_new_logop() /
1534 * newLOGOP(). This function exists mainly to avoid op_first assignment
1535 * being spread throughout this file.
1536 */
1537
6cb4123e
DM
1538LOGOP *
1539Perl_alloc_LOGOP(pTHX_ I32 type, OP *first, OP* other)
3253bf85 1540{
1e8db68a 1541 dVAR;
3253bf85 1542 LOGOP *logop;
29e61fd9 1543 OP *kid = first;
3253bf85 1544 NewOp(1101, logop, 1, LOGOP);
b9a07097 1545 OpTYPE_set(logop, type);
3253bf85
DM
1546 logop->op_first = first;
1547 logop->op_other = other;
d2d35729
FC
1548 if (first)
1549 logop->op_flags = OPf_KIDS;
e6dae479
FC
1550 while (kid && OpHAS_SIBLING(kid))
1551 kid = OpSIBLING(kid);
5e24af7d
DM
1552 if (kid)
1553 OpLASTSIB_set(kid, (OP*)logop);
3253bf85
DM
1554 return logop;
1555}
1556
1557
79072805
LW
1558/* Contextualizers */
1559
d9088386
Z
1560/*
1561=for apidoc Am|OP *|op_contextualize|OP *o|I32 context
1562
1563Applies a syntactic context to an op tree representing an expression.
2d7f6611 1564C<o> is the op tree, and C<context> must be C<G_SCALAR>, C<G_ARRAY>,
d9088386
Z
1565or C<G_VOID> to specify the context to apply. The modified op tree
1566is returned.
1567
1568=cut
1569*/
1570
1571OP *
1572Perl_op_contextualize(pTHX_ OP *o, I32 context)
1573{
1574 PERL_ARGS_ASSERT_OP_CONTEXTUALIZE;
1575 switch (context) {
1576 case G_SCALAR: return scalar(o);
1577 case G_ARRAY: return list(o);
1578 case G_VOID: return scalarvoid(o);
1579 default:
5637ef5b
NC
1580 Perl_croak(aTHX_ "panic: op_contextualize bad context %ld",
1581 (long) context);
d9088386
Z
1582 }
1583}
1584
5983a79d 1585/*
79072805 1586
5983a79d 1587=for apidoc Am|OP*|op_linklist|OP *o
72d33970 1588This function is the implementation of the L</LINKLIST> macro. It should
5983a79d
BM
1589not be called directly.
1590
1591=cut
1592*/
1593
1594OP *
1595Perl_op_linklist(pTHX_ OP *o)
79072805 1596{
3edf23ff 1597 OP *first;
79072805 1598
5983a79d 1599 PERL_ARGS_ASSERT_OP_LINKLIST;
7918f24d 1600
11343788
MB
1601 if (o->op_next)
1602 return o->op_next;
79072805
LW
1603
1604 /* establish postfix order */
3edf23ff
AL
1605 first = cUNOPo->op_first;
1606 if (first) {
eb578fdb 1607 OP *kid;
3edf23ff
AL
1608 o->op_next = LINKLIST(first);
1609 kid = first;
1610 for (;;) {
e6dae479 1611 OP *sibl = OpSIBLING(kid);
29e61fd9
DM
1612 if (sibl) {
1613 kid->op_next = LINKLIST(sibl);
1614 kid = sibl;
3edf23ff 1615 } else {
11343788 1616 kid->op_next = o;
3edf23ff
AL
1617 break;
1618 }
79072805
LW
1619 }
1620 }
1621 else
11343788 1622 o->op_next = o;
79072805 1623
11343788 1624 return o->op_next;
79072805
LW
1625}
1626
1f676739 1627static OP *
2dd5337b 1628S_scalarkids(pTHX_ OP *o)
79072805 1629{
11343788 1630 if (o && o->op_flags & OPf_KIDS) {
bfed75c6 1631 OP *kid;
e6dae479 1632 for (kid = cLISTOPo->op_first; kid; kid = OpSIBLING(kid))
79072805
LW
1633 scalar(kid);
1634 }
11343788 1635 return o;
79072805
LW
1636}
1637
76e3520e 1638STATIC OP *
cea2e8a9 1639S_scalarboolean(pTHX_ OP *o)
8990e307 1640{
7918f24d
NC
1641 PERL_ARGS_ASSERT_SCALARBOOLEAN;
1642
0a44e30b
DC
1643 if ((o->op_type == OP_SASSIGN && cBINOPo->op_first->op_type == OP_CONST &&
1644 !(cBINOPo->op_first->op_flags & OPf_SPECIAL)) ||
1645 (o->op_type == OP_NOT && cUNOPo->op_first->op_type == OP_SASSIGN &&
1646 cBINOPx(cUNOPo->op_first)->op_first->op_type == OP_CONST &&
1647 !(cBINOPx(cUNOPo->op_first)->op_first->op_flags & OPf_SPECIAL))) {
d008e5eb 1648 if (ckWARN(WARN_SYNTAX)) {
6867be6d 1649 const line_t oldline = CopLINE(PL_curcop);
a0d0e21e 1650
2b7cddde
NC
1651 if (PL_parser && PL_parser->copline != NOLINE) {
1652 /* This ensures that warnings are reported at the first line
1653 of the conditional, not the last. */
53a7735b 1654 CopLINE_set(PL_curcop, PL_parser->copline);
2b7cddde 1655 }
9014280d 1656 Perl_warner(aTHX_ packWARN(WARN_SYNTAX), "Found = in conditional, should be ==");
57843af0 1657 CopLINE_set(PL_curcop, oldline);
d008e5eb 1658 }
a0d0e21e 1659 }
11343788 1660 return scalar(o);
8990e307
LW
1661}
1662
0920b7fa 1663static SV *
637494ac 1664S_op_varname_subscript(pTHX_ const OP *o, int subscript_type)
0920b7fa
FC
1665{
1666 assert(o);
1667 assert(o->op_type == OP_PADAV || o->op_type == OP_RV2AV ||
1668 o->op_type == OP_PADHV || o->op_type == OP_RV2HV);
1669 {
1670 const char funny = o->op_type == OP_PADAV
1671 || o->op_type == OP_RV2AV ? '@' : '%';
1672 if (o->op_type == OP_RV2AV || o->op_type == OP_RV2HV) {
1673 GV *gv;
1674 if (cUNOPo->op_first->op_type != OP_GV
1675 || !(gv = cGVOPx_gv(cUNOPo->op_first)))
1676 return NULL;
637494ac 1677 return varname(gv, funny, 0, NULL, 0, subscript_type);
0920b7fa
FC
1678 }
1679 return
637494ac 1680 varname(MUTABLE_GV(PL_compcv), funny, o->op_targ, NULL, 0, subscript_type);
0920b7fa
FC
1681 }
1682}
1683
637494ac
TC
1684static SV *
1685S_op_varname(pTHX_ const OP *o)
1686{
1687 return S_op_varname_subscript(aTHX_ o, 1);
1688}
1689
429a2555 1690static void
2186f873
FC
1691S_op_pretty(pTHX_ const OP *o, SV **retsv, const char **retpv)
1692{ /* or not so pretty :-) */
2186f873
FC
1693 if (o->op_type == OP_CONST) {
1694 *retsv = cSVOPo_sv;
1695 if (SvPOK(*retsv)) {
1696 SV *sv = *retsv;
1697 *retsv = sv_newmortal();
1698 pv_pretty(*retsv, SvPVX_const(sv), SvCUR(sv), 32, NULL, NULL,
1699 PERL_PV_PRETTY_DUMP |PERL_PV_ESCAPE_UNI_DETECT);
1700 }
1701 else if (!SvOK(*retsv))
1702 *retpv = "undef";
1703 }
1704 else *retpv = "...";
1705}
1706
1707static void
429a2555
FC
1708S_scalar_slice_warning(pTHX_ const OP *o)
1709{
1710 OP *kid;
fe7df09e
FC
1711 const bool h = o->op_type == OP_HSLICE
1712 || (o->op_type == OP_NULL && o->op_targ == OP_HSLICE);
429a2555 1713 const char lbrack =
fe7df09e 1714 h ? '{' : '[';
429a2555 1715 const char rbrack =
fe7df09e 1716 h ? '}' : ']';
429a2555 1717 SV *name;
32e9ec8f 1718 SV *keysv = NULL; /* just to silence compiler warnings */
429a2555
FC
1719 const char *key = NULL;
1720
1721 if (!(o->op_private & OPpSLICEWARNING))
1722 return;
1723 if (PL_parser && PL_parser->error_count)
1724 /* This warning can be nonsensical when there is a syntax error. */
1725 return;
1726
1727 kid = cLISTOPo->op_first;
e6dae479 1728 kid = OpSIBLING(kid); /* get past pushmark */
429a2555
FC
1729 /* weed out false positives: any ops that can return lists */
1730 switch (kid->op_type) {
1731 case OP_BACKTICK:
1732 case OP_GLOB:
1733 case OP_READLINE:
1734 case OP_MATCH:
1735 case OP_RV2AV:
1736 case OP_EACH:
1737 case OP_VALUES:
1738 case OP_KEYS:
1739 case OP_SPLIT:
1740 case OP_LIST:
1741 case OP_SORT:
1742 case OP_REVERSE:
1743 case OP_ENTERSUB:
1744 case OP_CALLER:
1745 case OP_LSTAT:
1746 case OP_STAT:
1747 case OP_READDIR:
1748 case OP_SYSTEM:
1749 case OP_TMS:
1750 case OP_LOCALTIME:
1751 case OP_GMTIME:
1752 case OP_ENTEREVAL:
429a2555
FC
1753 return;
1754 }
7d3c8a68
SM
1755
1756 /* Don't warn if we have a nulled list either. */
1757 if (kid->op_type == OP_NULL && kid->op_targ == OP_LIST)
1758 return;
1759
e6dae479
FC
1760 assert(OpSIBLING(kid));
1761 name = S_op_varname(aTHX_ OpSIBLING(kid));
429a2555
FC
1762 if (!name) /* XS module fiddling with the op tree */
1763 return;
2186f873 1764 S_op_pretty(aTHX_ kid, &keysv, &key);
429a2555
FC
1765 assert(SvPOK(name));
1766 sv_chop(name,SvPVX(name)+1);
1767 if (key)
2186f873 1768 /* diag_listed_as: Scalar value @%s[%s] better written as $%s[%s] */
429a2555 1769 Perl_warner(aTHX_ packWARN(WARN_SYNTAX),
147e3846 1770 "Scalar value @%" SVf "%c%s%c better written as $%" SVf
429a2555 1771 "%c%s%c",
2186f873 1772 SVfARG(name), lbrack, key, rbrack, SVfARG(name),
429a2555
FC
1773 lbrack, key, rbrack);
1774 else
2186f873 1775 /* diag_listed_as: Scalar value @%s[%s] better written as $%s[%s] */
429a2555 1776 Perl_warner(aTHX_ packWARN(WARN_SYNTAX),
147e3846
KW
1777 "Scalar value @%" SVf "%c%" SVf "%c better written as $%"
1778 SVf "%c%" SVf "%c",
c1f6cd39
BF
1779 SVfARG(name), lbrack, SVfARG(keysv), rbrack,
1780 SVfARG(name), lbrack, SVfARG(keysv), rbrack);
429a2555
FC
1781}
1782
8990e307 1783OP *
864dbfa3 1784Perl_scalar(pTHX_ OP *o)
79072805
LW
1785{
1786 OP *kid;
1787
a0d0e21e 1788 /* assumes no premature commitment */
13765c85
DM
1789 if (!o || (PL_parser && PL_parser->error_count)
1790 || (o->op_flags & OPf_WANT)
5dc0d613 1791 || o->op_type == OP_RETURN)
7e363e51 1792 {
11343788 1793 return o;
7e363e51 1794 }
79072805 1795
5dc0d613 1796 o->op_flags = (o->op_flags & ~OPf_WANT) | OPf_WANT_SCALAR;
79072805 1797
11343788 1798 switch (o->op_type) {
79072805 1799 case OP_REPEAT:
11343788 1800 scalar(cBINOPo->op_first);
82e4f303
FC
1801 if (o->op_private & OPpREPEAT_DOLIST) {
1802 kid = cLISTOPx(cUNOPo->op_first)->op_first;
1803 assert(kid->op_type == OP_PUSHMARK);
e6dae479 1804 if (OpHAS_SIBLING(kid) && !OpHAS_SIBLING(OpSIBLING(kid))) {
82e4f303
FC
1805 op_null(cLISTOPx(cUNOPo->op_first)->op_first);
1806 o->op_private &=~ OPpREPEAT_DOLIST;
1807 }
1808 }
8990e307 1809 break;
79072805
LW
1810 case OP_OR:
1811 case OP_AND:
1812 case OP_COND_EXPR:
e6dae479 1813 for (kid = OpSIBLING(cUNOPo->op_first); kid; kid = OpSIBLING(kid))
8990e307 1814 scalar(kid);
79072805 1815 break;
924ba076 1816 /* FALLTHROUGH */
a6d8037e 1817 case OP_SPLIT:
79072805 1818 case OP_MATCH:
8782bef2 1819 case OP_QR:
79072805
LW
1820 case OP_SUBST:
1821 case OP_NULL:
8990e307 1822 default:
11343788 1823 if (o->op_flags & OPf_KIDS) {
e6dae479 1824 for (kid = cUNOPo->op_first; kid; kid = OpSIBLING(kid))
8990e307
LW
1825 scalar(kid);
1826 }
79072805
LW
1827 break;
1828 case OP_LEAVE:
1829 case OP_LEAVETRY:
5dc0d613 1830 kid = cLISTOPo->op_first;
54310121 1831 scalar(kid);
e6dae479 1832 kid = OpSIBLING(kid);
25b991bf
VP
1833 do_kids:
1834 while (kid) {
e6dae479 1835 OP *sib = OpSIBLING(kid);
7896dde7 1836 if (sib && kid->op_type != OP_LEAVEWHEN
e6dae479 1837 && ( OpHAS_SIBLING(sib) || sib->op_type != OP_NULL
34b54951
FC
1838 || ( sib->op_targ != OP_NEXTSTATE
1839 && sib->op_targ != OP_DBSTATE )))
c08f093b
VP
1840 scalarvoid(kid);
1841 else
54310121 1842 scalar(kid);
25b991bf 1843 kid = sib;
54310121 1844 }
11206fdd 1845 PL_curcop = &PL_compiling;
54310121 1846 break;
748a9306 1847 case OP_SCOPE:
79072805 1848 case OP_LINESEQ:
8990e307 1849 case OP_LIST:
25b991bf
VP
1850 kid = cLISTOPo->op_first;
1851 goto do_kids;
a801c63c 1852 case OP_SORT:
a2a5de95 1853 Perl_ck_warner(aTHX_ packWARN(WARN_VOID), "Useless use of sort in scalar context");
553e7bb0 1854 break;
95a31aad
FC
1855 case OP_KVHSLICE:
1856 case OP_KVASLICE:
2186f873
FC
1857 {
1858 /* Warn about scalar context */
1859 const char lbrack = o->op_type == OP_KVHSLICE ? '{' : '[';
1860 const char rbrack = o->op_type == OP_KVHSLICE ? '}' : ']';
1861 SV *name;
1862 SV *keysv;
1863 const char *key = NULL;
1864
1865 /* This warning can be nonsensical when there is a syntax error. */
1866 if (PL_parser && PL_parser->error_count)
1867 break;
1868
1869 if (!ckWARN(WARN_SYNTAX)) break;
1870
1871 kid = cLISTOPo->op_first;
e6dae479
FC
1872 kid = OpSIBLING(kid); /* get past pushmark */
1873 assert(OpSIBLING(kid));
1874 name = S_op_varname(aTHX_ OpSIBLING(kid));
2186f873
FC
1875 if (!name) /* XS module fiddling with the op tree */
1876 break;
1877 S_op_pretty(aTHX_ kid, &keysv, &key);
1878 assert(SvPOK(name));
1879 sv_chop(name,SvPVX(name)+1);
1880 if (key)
1881 /* diag_listed_as: %%s[%s] in scalar context better written as $%s[%s] */
1882 Perl_warner(aTHX_ packWARN(WARN_SYNTAX),
147e3846
KW
1883 "%%%" SVf "%c%s%c in scalar context better written "
1884 "as $%" SVf "%c%s%c",
2186f873
FC
1885 SVfARG(name), lbrack, key, rbrack, SVfARG(name),
1886 lbrack, key, rbrack);
1887 else
1888 /* diag_listed_as: %%s[%s] in scalar context better written as $%s[%s] */
1889 Perl_warner(aTHX_ packWARN(WARN_SYNTAX),
147e3846
KW
1890 "%%%" SVf "%c%" SVf "%c in scalar context better "
1891 "written as $%" SVf "%c%" SVf "%c",
c1f6cd39
BF
1892 SVfARG(name), lbrack, SVfARG(keysv), rbrack,
1893 SVfARG(name), lbrack, SVfARG(keysv), rbrack);
2186f873 1894 }
79072805 1895 }
11343788 1896 return o;
79072805
LW
1897}
1898
1899OP *
aa9d1253 1900Perl_scalarvoid(pTHX_ OP *arg)
79072805 1901{
27da23d5 1902 dVAR;
79072805 1903 OP *kid;
8990e307 1904 SV* sv;
aa9d1253
TC
1905 SSize_t defer_stack_alloc = 0;
1906 SSize_t defer_ix = -1;
1907 OP **defer_stack = NULL;
1908 OP *o = arg;
2ebea0a1 1909
7918f24d
NC
1910 PERL_ARGS_ASSERT_SCALARVOID;
1911
aa9d1253 1912 do {
19742f39 1913 U8 want;
aa9d1253
TC
1914 SV *useless_sv = NULL;
1915 const char* useless = NULL;
1916
26f0e7d5
TC
1917 if (o->op_type == OP_NEXTSTATE
1918 || o->op_type == OP_DBSTATE
1919 || (o->op_type == OP_NULL && (o->op_targ == OP_NEXTSTATE
1920 || o->op_targ == OP_DBSTATE)))
1921 PL_curcop = (COP*)o; /* for warning below */
1922
1923 /* assumes no premature commitment */
1924 want = o->op_flags & OPf_WANT;
1925 if ((want && want != OPf_WANT_SCALAR)
1926 || (PL_parser && PL_parser->error_count)
7896dde7 1927 || o->op_type == OP_RETURN || o->op_type == OP_REQUIRE || o->op_type == OP_LEAVEWHEN)
26f0e7d5
TC
1928 {
1929 continue;
1930 }
1c846c1f 1931
26f0e7d5
TC
1932 if ((o->op_private & OPpTARGET_MY)
1933 && (PL_opargs[o->op_type] & OA_TARGLEX))/* OPp share the meaning */
1934 {
0d18dd72
FC
1935 /* newASSIGNOP has already applied scalar context, which we
1936 leave, as if this op is inside SASSIGN. */
26f0e7d5
TC
1937 continue;
1938 }
79072805 1939
26f0e7d5 1940 o->op_flags = (o->op_flags & ~OPf_WANT) | OPf_WANT_VOID;
75068674 1941
26f0e7d5
TC
1942 switch (o->op_type) {
1943 default:
1944 if (!(PL_opargs[o->op_type] & OA_FOLDCONST))
1945 break;
1946 /* FALLTHROUGH */
1947 case OP_REPEAT:
1948 if (o->op_flags & OPf_STACKED)
1949 break;
1e2dd519
FC
1950 if (o->op_type == OP_REPEAT)
1951 scalar(cBINOPo->op_first);
26f0e7d5 1952 goto func_ops;
3d033384
Z
1953 case OP_CONCAT:
1954 if ((o->op_flags & OPf_STACKED) &&
1955 !(o->op_private & OPpCONCAT_NESTED))
1956 break;
1957 goto func_ops;
26f0e7d5
TC
1958 case OP_SUBSTR:
1959 if (o->op_private == 4)
1960 break;
1961 /* FALLTHROUGH */
26f0e7d5
TC
1962 case OP_WANTARRAY:
1963 case OP_GV:
1964 case OP_SMARTMATCH:
26f0e7d5
TC
1965 case OP_AV2ARYLEN:
1966 case OP_REF:
1967 case OP_REFGEN:
1968 case OP_SREFGEN:
1969 case OP_DEFINED:
1970 case OP_HEX:
1971 case OP_OCT:
1972 case OP_LENGTH:
1973 case OP_VEC:
1974 case OP_INDEX:
1975 case OP_RINDEX:
1976 case OP_SPRINTF:
26f0e7d5 1977 case OP_KVASLICE:
26f0e7d5
TC
1978 case OP_KVHSLICE:
1979 case OP_UNPACK:
1980 case OP_PACK:
1981 case OP_JOIN:
1982 case OP_LSLICE:
1983 case OP_ANONLIST:
1984 case OP_ANONHASH:
1985 case OP_SORT:
1986 case OP_REVERSE:
1987 case OP_RANGE:
1988 case OP_FLIP:
1989 case OP_FLOP:
1990 case OP_CALLER:
1991 case OP_FILENO:
1992 case OP_EOF:
1993 case OP_TELL:
1994 case OP_GETSOCKNAME:
1995 case OP_GETPEERNAME:
1996 case OP_READLINK:
1997 case OP_TELLDIR:
1998 case OP_GETPPID:
1999 case OP_GETPGRP:
2000 case OP_GETPRIORITY:
2001 case OP_TIME:
2002 case OP_TMS:
2003 case OP_LOCALTIME:
2004 case OP_GMTIME:
2005 case OP_GHBYNAME:
2006 case OP_GHBYADDR:
2007 case OP_GHOSTENT:
2008 case OP_GNBYNAME:
2009 case OP_GNBYADDR:
2010 case OP_GNETENT:
2011 case OP_GPBYNAME:
2012 case OP_GPBYNUMBER:
2013 case OP_GPROTOENT:
2014 case OP_GSBYNAME:
2015 case OP_GSBYPORT:
2016 case OP_GSERVENT:
2017 case OP_GPWNAM:
2018 case OP_GPWUID:
2019 case OP_GGRNAM:
2020 case OP_GGRGID:
2021 case OP_GETLOGIN:
2022 case OP_PROTOTYPE:
2023 case OP_RUNCV:
2024 func_ops:
9e209402
FC
2025 useless = OP_DESC(o);
2026 break;
2027
2028 case OP_GVSV:
2029 case OP_PADSV:
2030 case OP_PADAV:
2031 case OP_PADHV:
2032 case OP_PADANY:
2033 case OP_AELEM:
2034 case OP_AELEMFAST:
2035 case OP_AELEMFAST_LEX:
2036 case OP_ASLICE:
2037 case OP_HELEM:
2038 case OP_HSLICE:
26f0e7d5 2039 if (!(o->op_private & (OPpLVAL_INTRO|OPpOUR_INTRO)))
ea5519d6 2040 /* Otherwise it's "Useless use of grep iterator" */
3c3f8cd6 2041 useless = OP_DESC(o);
ea5519d6 2042 break;
26f0e7d5
TC
2043
2044 case OP_SPLIT:
5012eebe 2045 if (!(o->op_private & OPpSPLIT_ASSIGN))
26f0e7d5
TC
2046 useless = OP_DESC(o);
2047 break;
2048
2049 case OP_NOT:
2050 kid = cUNOPo->op_first;
2051 if (kid->op_type != OP_MATCH && kid->op_type != OP_SUBST &&
2052 kid->op_type != OP_TRANS && kid->op_type != OP_TRANSR) {
2053 goto func_ops;
2054 }
2055 useless = "negative pattern binding (!~)";
2056 break;
2057
2058 case OP_SUBST:
2059 if (cPMOPo->op_pmflags & PMf_NONDESTRUCT)
2060 useless = "non-destructive substitution (s///r)";
2061 break;
2062
2063 case OP_TRANSR:
2064 useless = "non-destructive transliteration (tr///r)";
2065 break;
2066
2067 case OP_RV2GV:
2068 case OP_RV2SV:
2069 case OP_RV2AV:
2070 case OP_RV2HV:
2071 if (!(o->op_private & (OPpLVAL_INTRO|OPpOUR_INTRO)) &&
e6dae479 2072 (!OpHAS_SIBLING(o) || OpSIBLING(o)->op_type != OP_READLINE))
26f0e7d5
TC
2073 useless = "a variable";
2074 break;
2075
2076 case OP_CONST:
2077 sv = cSVOPo_sv;
2078 if (cSVOPo->op_private & OPpCONST_STRICT)
2079 no_bareword_allowed(o);
2080 else {
2081 if (ckWARN(WARN_VOID)) {
2082 NV nv;
2083 /* don't warn on optimised away booleans, eg
2084 * use constant Foo, 5; Foo || print; */
2085 if (cSVOPo->op_private & OPpCONST_SHORTCIRCUIT)
2086 useless = NULL;
2087 /* the constants 0 and 1 are permitted as they are
2088 conventionally used as dummies in constructs like
2089 1 while some_condition_with_side_effects; */
2090 else if (SvNIOK(sv) && ((nv = SvNV(sv)) == 0.0 || nv == 1.0))
2091 useless = NULL;
2092 else if (SvPOK(sv)) {
2093 SV * const dsv = newSVpvs("");
2094 useless_sv
2095 = Perl_newSVpvf(aTHX_
2096 "a constant (%s)",
2097 pv_pretty(dsv, SvPVX_const(sv),
2098 SvCUR(sv), 32, NULL, NULL,
2099 PERL_PV_PRETTY_DUMP
2100 | PERL_PV_ESCAPE_NOCLEAR
2101 | PERL_PV_ESCAPE_UNI_DETECT));
2102 SvREFCNT_dec_NN(dsv);
2103 }
2104 else if (SvOK(sv)) {
147e3846 2105 useless_sv = Perl_newSVpvf(aTHX_ "a constant (%" SVf ")", SVfARG(sv));
26f0e7d5
TC
2106 }
2107 else
2108 useless = "a constant (undef)";
2109 }
2110 }
2111 op_null(o); /* don't execute or even remember it */
2112 break;
79072805 2113
26f0e7d5 2114 case OP_POSTINC:
b9a07097 2115 OpTYPE_set(o, OP_PREINC); /* pre-increment is faster */
26f0e7d5 2116 break;
79072805 2117
26f0e7d5 2118 case OP_POSTDEC:
b9a07097 2119 OpTYPE_set(o, OP_PREDEC); /* pre-decrement is faster */
26f0e7d5 2120 break;
79072805 2121
26f0e7d5 2122 case OP_I_POSTINC:
b9a07097 2123 OpTYPE_set(o, OP_I_PREINC); /* pre-increment is faster */
26f0e7d5 2124 break;
79072805 2125
26f0e7d5 2126 case OP_I_POSTDEC:
b9a07097 2127 OpTYPE_set(o, OP_I_PREDEC); /* pre-decrement is faster */
26f0e7d5 2128 break;
679d6c4e 2129
26f0e7d5
TC
2130 case OP_SASSIGN: {
2131 OP *rv2gv;
2132 UNOP *refgen, *rv2cv;
2133 LISTOP *exlist;
679d6c4e 2134
26f0e7d5
TC
2135 if ((o->op_private & ~OPpASSIGN_BACKWARDS) != 2)
2136 break;
f2f8fd84 2137
26f0e7d5
TC
2138 rv2gv = ((BINOP *)o)->op_last;
2139 if (!rv2gv || rv2gv->op_type != OP_RV2GV)
2140 break;
f2f8fd84 2141
26f0e7d5 2142 refgen = (UNOP *)((BINOP *)o)->op_first;
f2f8fd84 2143
26f0e7d5
TC
2144 if (!refgen || (refgen->op_type != OP_REFGEN
2145 && refgen->op_type != OP_SREFGEN))
2146 break;
f2f8fd84 2147
26f0e7d5
TC
2148 exlist = (LISTOP *)refgen->op_first;
2149 if (!exlist || exlist->op_type != OP_NULL
2150 || exlist->op_targ != OP_LIST)
2151 break;
f2f8fd84 2152
26f0e7d5
TC
2153 if (exlist->op_first->op_type != OP_PUSHMARK
2154 && exlist->op_first != exlist->op_last)
2155 break;
f2f8fd84 2156
26f0e7d5 2157 rv2cv = (UNOP*)exlist->op_last;
f2f8fd84 2158
26f0e7d5
TC
2159 if (rv2cv->op_type != OP_RV2CV)
2160 break;
f2f8fd84 2161
26f0e7d5
TC
2162 assert ((rv2gv->op_private & OPpDONT_INIT_GV) == 0);
2163 assert ((o->op_private & OPpASSIGN_CV_TO_GV) == 0);
2164 assert ((rv2cv->op_private & OPpMAY_RETURN_CONSTANT) == 0);
f2f8fd84 2165
26f0e7d5
TC
2166 o->op_private |= OPpASSIGN_CV_TO_GV;
2167 rv2gv->op_private |= OPpDONT_INIT_GV;
2168 rv2cv->op_private |= OPpMAY_RETURN_CONSTANT;
f2f8fd84 2169
26f0e7d5
TC
2170 break;
2171 }
540dd770 2172
26f0e7d5
TC
2173 case OP_AASSIGN: {
2174 inplace_aassign(o);
2175 break;
2176 }
edbe35ea 2177
26f0e7d5
TC
2178 case OP_OR:
2179 case OP_AND:
2180 kid = cLOGOPo->op_first;
2181 if (kid->op_type == OP_NOT
2182 && (kid->op_flags & OPf_KIDS)) {
2183 if (o->op_type == OP_AND) {
b9a07097 2184 OpTYPE_set(o, OP_OR);
26f0e7d5 2185 } else {
b9a07097 2186 OpTYPE_set(o, OP_AND);
26f0e7d5
TC
2187 }
2188 op_null(kid);
2189 }
2190 /* FALLTHROUGH */
5aabfad6 2191
26f0e7d5
TC
2192 case OP_DOR:
2193 case OP_COND_EXPR:
2194 case OP_ENTERGIVEN:
7896dde7 2195 case OP_ENTERWHEN:
e6dae479 2196 for (kid = OpSIBLING(cUNOPo->op_first); kid; kid = OpSIBLING(kid))
26f0e7d5
TC
2197 if (!(kid->op_flags & OPf_KIDS))
2198 scalarvoid(kid);
2199 else
2200 DEFER_OP(kid);
aa9d1253 2201 break;
095b19d1 2202
26f0e7d5
TC
2203 case OP_NULL:
2204 if (o->op_flags & OPf_STACKED)
2205 break;
2206 /* FALLTHROUGH */
2207 case OP_NEXTSTATE:
2208 case OP_DBSTATE:
2209 case OP_ENTERTRY:
2210 case OP_ENTER:
2211 if (!(o->op_flags & OPf_KIDS))
2212 break;
2213 /* FALLTHROUGH */
2214 case OP_SCOPE:
2215 case OP_LEAVE:
2216 case OP_LEAVETRY:
2217 case OP_LEAVELOOP:
2218 case OP_LINESEQ:
7896dde7
Z
2219 case OP_LEAVEGIVEN:
2220 case OP_LEAVEWHEN:
26f0e7d5 2221 kids:
e6dae479 2222 for (kid = cLISTOPo->op_first; kid; kid = OpSIBLING(kid))
26f0e7d5
TC
2223 if (!(kid->op_flags & OPf_KIDS))
2224 scalarvoid(kid);
2225 else
2226 DEFER_OP(kid);
2227 break;
2228 case OP_LIST:
2229 /* If the first kid after pushmark is something that the padrange
2230 optimisation would reject, then null the list and the pushmark.
2231 */
2232 if ((kid = cLISTOPo->op_first)->op_type == OP_PUSHMARK
e6dae479 2233 && ( !(kid = OpSIBLING(kid))
26f0e7d5
TC
2234 || ( kid->op_type != OP_PADSV
2235 && kid->op_type != OP_PADAV
2236 && kid->op_type != OP_PADHV)
2237 || kid->op_private & ~OPpLVAL_INTRO
e6dae479 2238 || !(kid = OpSIBLING(kid))
26f0e7d5
TC
2239 || ( kid->op_type != OP_PADSV
2240 && kid->op_type != OP_PADAV
2241 && kid->op_type != OP_PADHV)
2242 || kid->op_private & ~OPpLVAL_INTRO)
2243 ) {
2244 op_null(cUNOPo->op_first); /* NULL the pushmark */
2245 op_null(o); /* NULL the list */
2246 }
2247 goto kids;
2248 case OP_ENTEREVAL:
2249 scalarkids(o);
2250 break;
2251 case OP_SCALAR:
2252 scalar(o);
2253 break;
2254 }
2255
2256 if (useless_sv) {
2257 /* mortalise it, in case warnings are fatal. */
2258 Perl_ck_warner(aTHX_ packWARN(WARN_VOID),
147e3846 2259 "Useless use of %" SVf " in void context",
26f0e7d5
TC
2260 SVfARG(sv_2mortal(useless_sv)));
2261 }
2262 else if (useless) {
3c3f8cd6
AB
2263 Perl_ck_warner(aTHX_ packWARN(WARN_VOID),
2264 "Useless use of %s in void context",
2265 useless);
26f0e7d5 2266 }
aa9d1253
TC
2267 } while ( (o = POP_DEFERRED_OP()) );
2268
2269 Safefree(defer_stack);
2270
2271 return arg;
79072805
LW
2272}
2273
1f676739 2274static OP *
412da003 2275S_listkids(pTHX_ OP *o)
79072805 2276{
11343788 2277 if (o && o->op_flags & OPf_KIDS) {
6867be6d 2278 OP *kid;
e6dae479 2279 for (kid = cLISTOPo->op_first; kid; kid = OpSIBLING(kid))
79072805
LW
2280 list(kid);
2281 }
11343788 2282 return o;
79072805
LW
2283}
2284
2285OP *
864dbfa3 2286Perl_list(pTHX_ OP *o)
79072805
LW
2287{
2288 OP *kid;
2289
a0d0e21e 2290 /* assumes no premature commitment */
13765c85
DM
2291 if (!o || (o->op_flags & OPf_WANT)
2292 || (PL_parser && PL_parser->error_count)
5dc0d613 2293 || o->op_type == OP_RETURN)
7e363e51 2294 {
11343788 2295 return o;
7e363e51 2296 }
79072805 2297
b162f9ea 2298 if ((o->op_private & OPpTARGET_MY)
7e363e51
GS
2299 && (PL_opargs[o->op_type] & OA_TARGLEX))/* OPp share the meaning */
2300 {
b162f9ea 2301 return o; /* As if inside SASSIGN */
7e363e51 2302 }
1c846c1f 2303
5dc0d613 2304 o->op_flags = (o->op_flags & ~OPf_WANT) | OPf_WANT_LIST;
79072805 2305
11343788 2306 switch (o->op_type) {
79072805 2307 case OP_FLOP:
11343788 2308 list(cBINOPo->op_first);
79072805 2309 break;
c57eecc5
FC
2310 case OP_REPEAT:
2311 if (o->op_private & OPpREPEAT_DOLIST
2312 && !(o->op_flags & OPf_STACKED))
2313 {
2314 list(cBINOPo->op_first);
2315 kid = cBINOPo->op_last;
2316 if (kid->op_type == OP_CONST && SvIOK(kSVOP_sv)
2317 && SvIVX(kSVOP_sv) == 1)
2318 {
2319 op_null(o); /* repeat */
2320 op_null(cUNOPx(cBINOPo->op_first)->op_first);/* pushmark */
2321 /* const (rhs): */
2322 op_free(op_sibling_splice(o, cBINOPo->op_first, 1, NULL));
2323 }
2324 }
2325 break;
79072805
LW
2326 case OP_OR:
2327 case OP_AND:
2328 case OP_COND_EXPR:
e6dae479 2329 for (kid = OpSIBLING(cUNOPo->op_first); kid; kid = OpSIBLING(kid))
79072805
LW
2330 list(kid);
2331 break;
2332 default:
2333 case OP_MATCH:
8782bef2 2334 case OP_QR:
79072805
LW
2335 case OP_SUBST:
2336 case OP_NULL:
11343788 2337 if (!(o->op_flags & OPf_KIDS))
79072805 2338 break;
11343788
MB
2339 if (!o->op_next && cUNOPo->op_first->op_type == OP_FLOP) {
2340 list(cBINOPo->op_first);
2341 return gen_constant_list(o);
79072805 2342 }
6aa68307
FC
2343 listkids(o);
2344 break;
79072805 2345 case OP_LIST:
11343788 2346 listkids(o);
6aa68307
FC
2347 if (cLISTOPo->op_first->op_type == OP_PUSHMARK) {
2348 op_null(cUNOPo->op_first); /* NULL the pushmark */
2349 op_null(o); /* NULL the list */
2350 }
79072805
LW
2351 break;
2352 case OP_LEAVE:
2353 case OP_LEAVETRY:
5dc0d613 2354 kid = cLISTOPo->op_first;
54310121 2355 list(kid);
e6dae479 2356 kid = OpSIBLING(kid);
25b991bf
VP
2357 do_kids:
2358 while (kid) {
e6dae479 2359 OP *sib = OpSIBLING(kid);
7896dde7 2360 if (sib && kid->op_type != OP_LEAVEWHEN)
c08f093b
VP
2361 scalarvoid(kid);
2362 else
54310121 2363 list(kid);
25b991bf 2364 kid = sib;
54310121 2365 }
11206fdd 2366 PL_curcop = &PL_compiling;
54310121 2367 break;
748a9306 2368 case OP_SCOPE:
79072805 2369 case OP_LINESEQ:
25b991bf
VP
2370 kid = cLISTOPo->op_first;
2371 goto do_kids;
79072805 2372 }
11343788 2373 return o;
79072805
LW
2374}
2375
1f676739 2376static OP *
2dd5337b 2377S_scalarseq(pTHX_ OP *o)
79072805 2378{
11343788 2379 if (o) {
1496a290
AL
2380 const OPCODE type = o->op_type;
2381
2382 if (type == OP_LINESEQ || type == OP_SCOPE ||
2383 type == OP_LEAVE || type == OP_LEAVETRY)
463ee0b2 2384 {
b7bea5da
FC
2385 OP *kid, *sib;
2386 for (kid = cLISTOPo->op_first; kid; kid = sib) {
e6dae479
FC
2387 if ((sib = OpSIBLING(kid))
2388 && ( OpHAS_SIBLING(sib) || sib->op_type != OP_NULL
b7bea5da
FC
2389 || ( sib->op_targ != OP_NEXTSTATE
2390 && sib->op_targ != OP_DBSTATE )))
2391 {
463ee0b2 2392 scalarvoid(kid);
ed6116ce 2393 }
463ee0b2 2394 }
3280af22 2395 PL_curcop = &PL_compiling;
79072805 2396 }
11343788 2397 o->op_flags &= ~OPf_PARENS;
3280af22 2398 if (PL_hints & HINT_BLOCK_SCOPE)
11343788 2399 o->op_flags |= OPf_PARENS;
79072805 2400 }
8990e307 2401 else
11343788
MB
2402 o = newOP(OP_STUB, 0);
2403 return o;
79072805
LW
2404}
2405
76e3520e 2406STATIC OP *
cea2e8a9 2407S_modkids(pTHX_ OP *o, I32 type)
79072805 2408{
11343788 2409 if (o && o->op_flags & OPf_KIDS) {
6867be6d 2410 OP *kid;
e6dae479 2411 for (kid = cLISTOPo->op_first; kid; kid = OpSIBLING(kid))
3ad73efd 2412 op_lvalue(kid, type);
79072805 2413 }
11343788 2414 return o;
79072805
LW
2415}
2416
12ee5d32
DM
2417
2418/* for a helem/hslice/kvslice, if its a fixed hash, croak on invalid
2419 * const fields. Also, convert CONST keys to HEK-in-SVs.
2420 * rop is the op that retrieves the hash;
2421 * key_op is the first key
2422 */
2423
f9db5646 2424STATIC void
fedf30e1 2425S_check_hash_fields_and_hekify(pTHX_ UNOP *rop, SVOP *key_op)
12ee5d32
DM
2426{
2427 PADNAME *lexname;
2428 GV **fields;
2429 bool check_fields;
2430
2431 /* find the padsv corresponding to $lex->{} or @{$lex}{} */
2432 if (rop) {
2433 if (rop->op_first->op_type == OP_PADSV)
2434 /* @$hash{qw(keys here)} */
2435 rop = (UNOP*)rop->op_first;
2436 else {
2437 /* @{$hash}{qw(keys here)} */
2438 if (rop->op_first->op_type == OP_SCOPE
2439 && cLISTOPx(rop->op_first)->op_last->op_type == OP_PADSV)
2440 {
2441 rop = (UNOP*)cLISTOPx(rop->op_first)->op_last;
2442 }
2443 else
2444 rop = NULL;
2445 }
2446 }
2447
2448 lexname = NULL; /* just to silence compiler warnings */
2449 fields = NULL; /* just to silence compiler warnings */
2450
2451 check_fields =
2452 rop
2453 && (lexname = padnamelist_fetch(PL_comppad_name, rop->op_targ),
2454 SvPAD_TYPED(lexname))
2455 && (fields = (GV**)hv_fetchs(PadnameTYPE(lexname), "FIELDS", FALSE))
2456 && isGV(*fields) && GvHV(*fields);
2457
e6dae479 2458 for (; key_op; key_op = (SVOP*)OpSIBLING(key_op)) {
12ee5d32
DM
2459 SV **svp, *sv;
2460 if (key_op->op_type != OP_CONST)
2461 continue;
2462 svp = cSVOPx_svp(key_op);
2463
e1ccd220
DIM
2464 /* make sure it's not a bareword under strict subs */
2465 if (key_op->op_private & OPpCONST_BARE &&
2466 key_op->op_private & OPpCONST_STRICT)
2467 {
2468 no_bareword_allowed((OP*)key_op);
2469 }
2470
12ee5d32
DM
2471 /* Make the CONST have a shared SV */
2472 if ( !SvIsCOW_shared_hash(sv = *svp)
2473 && SvTYPE(sv) < SVt_PVMG
2474 && SvOK(sv)
2475 && !SvROK(sv))
2476 {
2477 SSize_t keylen;
2478 const char * const key = SvPV_const(sv, *(STRLEN*)&keylen);
2479 SV *nsv = newSVpvn_share(key, SvUTF8(sv) ? -keylen : keylen, 0);
2480 SvREFCNT_dec_NN(sv);
2481 *svp = nsv;
2482 }
2483
2484 if ( check_fields
2485 && !hv_fetch_ent(GvHV(*fields), *svp, FALSE, 0))
2486 {
147e3846
KW
2487 Perl_croak(aTHX_ "No such class field \"%" SVf "\" "
2488 "in variable %" PNf " of type %" HEKf,
12ee5d32
DM
2489 SVfARG(*svp), PNfARG(lexname),
2490 HEKfARG(HvNAME_HEK(PadnameTYPE(lexname))));
2491 }
2492 }
2493}
2494
e839e6ed
DM
2495/* info returned by S_sprintf_is_multiconcatable() */
2496
2497struct sprintf_ismc_info {
ca84e88e 2498 SSize_t nargs; /* num of args to sprintf (not including the format) */
e839e6ed
DM
2499 char *start; /* start of raw format string */
2500 char *end; /* bytes after end of raw format string */
2501 STRLEN total_len; /* total length (in bytes) of format string, not
2502 including '%s' and half of '%%' */
2503 STRLEN variant; /* number of bytes by which total_len_p would grow
2504 if upgraded to utf8 */
2505 bool utf8; /* whether the format is utf8 */
2506};
2507
2508
2509/* is the OP_SPRINTF o suitable for converting into a multiconcat op?
2510 * i.e. its format argument is a const string with only '%s' and '%%'
2511 * formats, and the number of args is known, e.g.
2512 * sprintf "a=%s f=%s", $a[0], scalar(f());
2513 * but not
2514 * sprintf "i=%d a=%s f=%s", $i, @a, f();
2515 *
2516 * If successful, the sprintf_ismc_info struct pointed to by info will be
2517 * populated.
2518 */
2519
2520STATIC bool
2521S_sprintf_is_multiconcatable(pTHX_ OP *o,struct sprintf_ismc_info *info)
2522{
2523 OP *pm, *constop, *kid;
2524 SV *sv;
2525 char *s, *e, *p;
ca84e88e 2526 SSize_t nargs, nformats;
e839e6ed
DM
2527 STRLEN cur, total_len, variant;
2528 bool utf8;
2529
2530 /* if sprintf's behaviour changes, die here so that someone
2531 * can decide whether to enhance this function or skip optimising
2532 * under those new circumstances */
2533 assert(!(o->op_flags & OPf_STACKED));
2534 assert(!(PL_opargs[OP_SPRINTF] & OA_TARGLEX));
2535 assert(!(o->op_private & ~OPpARG4_MASK));
2536
2537 pm = cUNOPo->op_first;
2538 if (pm->op_type != OP_PUSHMARK) /* weird coreargs stuff */
2539 return FALSE;
2540 constop = OpSIBLING(pm);
2541 if (!constop || constop->op_type != OP_CONST)
2542 return FALSE;
2543 sv = cSVOPx_sv(constop);
2544 if (SvMAGICAL(sv) || !SvPOK(sv))
2545 return FALSE;
2546
2547 s = SvPV(sv, cur);
2548 e = s + cur;
2549
2550 /* Scan format for %% and %s and work out how many %s there are.
2551 * Abandon if other format types are found.
2552 */
2553
2554 nformats = 0;
2555 total_len = 0;
2556 variant = 0;
2557
2558 for (p = s; p < e; p++) {
2559 if (*p != '%') {
2560 total_len++;
b3baa1fe 2561 if (!UTF8_IS_INVARIANT(*p))
e839e6ed
DM
2562 variant++;
2563 continue;
2564 }
2565 p++;
2566 if (p >= e)
2567 return FALSE; /* lone % at end gives "Invalid conversion" */
2568 if (*p == '%')
2569 total_len++;
2570 else if (*p == 's')
2571 nformats++;
2572 else
2573 return FALSE;
2574 }
2575
2576 if (!nformats || nformats > PERL_MULTICONCAT_MAXARG)
2577 return FALSE;
2578
2579 utf8 = cBOOL(SvUTF8(sv));
2580 if (utf8)
2581 variant = 0;
2582
2583 /* scan args; they must all be in scalar cxt */
2584
2585 nargs = 0;
2586 kid = OpSIBLING(constop);
2587
2588 while (kid) {
2589 if ((kid->op_flags & OPf_WANT) != OPf_WANT_SCALAR)
2590 return FALSE;
2591 nargs++;
2592 kid = OpSIBLING(kid);
2593 }
2594
2595 if (nargs != nformats)
2596 return FALSE; /* e.g. sprintf("%s%s", $a); */
2597
2598
2599 info->nargs = nargs;
2600 info->start = s;
2601 info->end = e;
2602 info->total_len = total_len;
2603 info->variant = variant;
2604 info->utf8 = utf8;
2605
2606 return TRUE;
2607}
2608
2609
2610
2611/* S_maybe_multiconcat():
2612 *
2613 * given an OP_STRINGIFY, OP_SASSIGN, OP_CONCAT or OP_SPRINTF op, possibly
2614 * convert it (and its children) into an OP_MULTICONCAT. See the code
2615 * comments just before pp_multiconcat() for the full details of what
2616 * OP_MULTICONCAT supports.
2617 *
2618 * Basically we're looking for an optree with a chain of OP_CONCATS down
2619 * the LHS (or an OP_SPRINTF), with possibly an OP_SASSIGN, and/or
2620 * OP_STRINGIFY, and/or OP_CONCAT acting as '.=' at its head, e.g.
2621 *
2622 * $x = "$a$b-$c"
2623 *
2624 * looks like
2625 *
2626 * SASSIGN
2627 * |
2628 * STRINGIFY -- PADSV[$x]
2629 * |
2630 * |
2631 * ex-PUSHMARK -- CONCAT/S
2632 * |
2633 * CONCAT/S -- PADSV[$d]
2634 * |
2635 * CONCAT -- CONST["-"]
2636 * |
2637 * PADSV[$a] -- PADSV[$b]
2638 *
2639 * Note that at this stage the OP_SASSIGN may have already been optimised
2640 * away with OPpTARGET_MY set on the OP_STRINGIFY or OP_CONCAT.
2641 */
2642
2643STATIC void
2644S_maybe_multiconcat(pTHX_ OP *o)
2645{
2646 OP *lastkidop; /* the right-most of any kids unshifted onto o */
2647 OP *topop; /* the top-most op in the concat tree (often equals o,
2648 unless there are assign/stringify ops above it */
2649 OP *parentop; /* the parent op of topop (or itself if no parent) */
2650 OP *targmyop; /* the op (if any) with the OPpTARGET_MY flag */
2651 OP *targetop; /* the op corresponding to target=... or target.=... */
2652 OP *stringop; /* the OP_STRINGIFY op, if any */
2653 OP *nextop; /* used for recreating the op_next chain without consts */
2654 OP *kid; /* general-purpose op pointer */
2655 UNOP_AUX_item *aux;
2656 UNOP_AUX_item *lenp;
2657 char *const_str, *p;
2658 struct sprintf_ismc_info sprintf_info;
2659
2660 /* store info about each arg in args[];
2661 * toparg is the highest used slot; argp is a general
2662 * pointer to args[] slots */
2663 struct {
2664 void *p; /* initially points to const sv (or null for op);
2665 later, set to SvPV(constsv), with ... */
2666 STRLEN len; /* ... len set to SvPV(..., len) */
2667 } *argp, *toparg, args[PERL_MULTICONCAT_MAXARG*2 + 1];
2668
ca84e88e
DM
2669 SSize_t nargs = 0;
2670 SSize_t nconst = 0;
f08f2d03 2671 SSize_t nadjconst = 0; /* adjacent consts - may be demoted to args */
e839e6ed
DM
2672 STRLEN variant;
2673 bool utf8 = FALSE;
2674 bool kid_is_last = FALSE; /* most args will be the RHS kid of a concat op;
2675 the last-processed arg will the LHS of one,
2676 as args are processed in reverse order */
2677 U8 stacked_last = 0; /* whether the last seen concat op was STACKED */
2678 STRLEN total_len = 0; /* sum of the lengths of the const segments */
2679 U8 flags = 0; /* what will become the op_flags and ... */
2680 U8 private_flags = 0; /* ... op_private of the multiconcat op */
2681 bool is_sprintf = FALSE; /* we're optimising an sprintf */
2682 bool is_targable = FALSE; /* targetop is an OPpTARGET_MY candidate */
f08f2d03 2683 bool prev_was_const = FALSE; /* previous arg was a const */
e839e6ed
DM
2684
2685 /* -----------------------------------------------------------------
2686 * Phase 1:
2687 *
2688 * Examine the optree non-destructively to determine whether it's
2689 * suitable to be converted into an OP_MULTICONCAT. Accumulate
2690 * information about the optree in args[].
2691 */
2692
2693 argp = args;
2694 targmyop = NULL;
2695 targetop = NULL;
2696 stringop = NULL;
2697 topop = o;
2698 parentop = o;
2699
2700 assert( o->op_type == OP_SASSIGN
2701 || o->op_type == OP_CONCAT
2702 || o->op_type == OP_SPRINTF
2703 || o->op_type == OP_STRINGIFY);
2704
da431b10
JH
2705 Zero(&sprintf_info, 1, struct sprintf_ismc_info);
2706
e839e6ed
DM
2707 /* first see if, at the top of the tree, there is an assign,
2708 * append and/or stringify */
2709
2710 if (topop->op_type == OP_SASSIGN) {
2711 /* expr = ..... */
2712 if (o->op_ppaddr != PL_ppaddr[OP_SASSIGN])
2713 return;
2714 if (o->op_private & (OPpASSIGN_BACKWARDS|OPpASSIGN_CV_TO_GV))
2715 return;
2716 assert(!(o->op_private & ~OPpARG2_MASK)); /* barf on unknown flags */
2717
2718 parentop = topop;
2719 topop = cBINOPo->op_first;
2720 targetop = OpSIBLING(topop);
2721 if (!targetop) /* probably some sort of syntax error */
2722 return;
2723 }
2724 else if ( topop->op_type == OP_CONCAT
2725 && (topop->op_flags & OPf_STACKED)
62c1220c
DM
2726 && (cUNOPo->op_first->op_flags & OPf_MOD)
2727 && (!(topop->op_private & OPpCONCAT_NESTED))
2728 )
e839e6ed
DM
2729 {
2730 /* expr .= ..... */
2731
2732 /* OPpTARGET_MY shouldn't be able to be set here. If it is,
2733 * decide what to do about it */
2734 assert(!(o->op_private & OPpTARGET_MY));
2735
2736 /* barf on unknown flags */
2737 assert(!(o->op_private & ~(OPpARG2_MASK|OPpTARGET_MY)));
2738 private_flags |= OPpMULTICONCAT_APPEND;
2739 targetop = cBINOPo->op_first;
2740 parentop = topop;
2741 topop = OpSIBLING(targetop);
2742
2743 /* $x .= <FOO> gets optimised to rcatline instead */
2744 if (topop->op_type == OP_READLINE)
2745 return;
2746 }
2747
2748 if (targetop) {
2749 /* Can targetop (the LHS) if it's a padsv, be be optimised
2750 * away and use OPpTARGET_MY instead?
2751 */
2752 if ( (targetop->op_type == OP_PADSV)
2753 && !(targetop->op_private & OPpDEREF)
2754 && !(targetop->op_private & OPpPAD_STATE)
2755 /* we don't support 'my $x .= ...' */
2756 && ( o->op_type == OP_SASSIGN
2757 || !(targetop->op_private & OPpLVAL_INTRO))
2758 )
2759 is_targable = TRUE;
2760 }
2761
2762 if (topop->op_type == OP_STRINGIFY) {
2763 if (topop->op_ppaddr != PL_ppaddr[OP_STRINGIFY])
2764 return;
2765 stringop = topop;
2766
2767 /* barf on unknown flags */
2768 assert(!(o->op_private & ~(OPpARG4_MASK|OPpTARGET_MY)));
2769
2770 if ((topop->op_private & OPpTARGET_MY)) {
2771 if (o->op_type == OP_SASSIGN)
2772 return; /* can't have two assigns */
2773 targmyop = topop;
2774 }
2775
2776 private_flags |= OPpMULTICONCAT_STRINGIFY;
2777 parentop = topop;
2778 topop = cBINOPx(topop)->op_first;
2779 assert(OP_TYPE_IS_OR_WAS_NN(topop, OP_PUSHMARK));
2780 topop = OpSIBLING(topop);
2781 }
2782
2783 if (topop->op_type == OP_SPRINTF) {
2784 if (topop->op_ppaddr != PL_ppaddr[OP_SPRINTF])
2785 return;
2786 if (S_sprintf_is_multiconcatable(aTHX_ topop, &sprintf_info)) {
2787 nargs = sprintf_info.nargs;
2788 total_len = sprintf_info.total_len;
2789 variant = sprintf_info.variant;
2790 utf8 = sprintf_info.utf8;
2791 is_sprintf = TRUE;
2792 private_flags |= OPpMULTICONCAT_FAKE;
2793 toparg = argp;
2794 /* we have an sprintf op rather than a concat optree.
2795 * Skip most of the code below which is associated with
2796 * processing that optree. We also skip phase 2, determining
2797 * whether its cost effective to optimise, since for sprintf,
2798 * multiconcat is *always* faster */
2799 goto create_aux;
2800 }
2801 /* note that even if the sprintf itself isn't multiconcatable,
2802 * the expression as a whole may be, e.g. in
2803 * $x .= sprintf("%d",...)
2804 * the sprintf op will be left as-is, but the concat/S op may
2805 * be upgraded to multiconcat
2806 */
2807 }
2808 else if (topop->op_type == OP_CONCAT) {
2809 if (topop->op_ppaddr != PL_ppaddr[OP_CONCAT])
2810 return;
2811
2812 if ((topop->op_private & OPpTARGET_MY)) {
2813 if (o->op_type == OP_SASSIGN || targmyop)
2814 return; /* can't have two assigns */
2815 targmyop = topop;
2816 }
2817 }
2818
2819 /* Is it safe to convert a sassign/stringify/concat op into
2820 * a multiconcat? */
2821 assert((PL_opargs[OP_SASSIGN] & OA_CLASS_MASK) == OA_BINOP);
2822 assert((PL_opargs[OP_CONCAT] & OA_CLASS_MASK) == OA_BINOP);
2823 assert((PL_opargs[OP_STRINGIFY] & OA_CLASS_MASK) == OA_LISTOP);
2824 assert((PL_opargs[OP_SPRINTF] & OA_CLASS_MASK) == OA_LISTOP);
2825 STATIC_ASSERT_STMT( STRUCT_OFFSET(BINOP, op_last)
2826 == STRUCT_OFFSET(UNOP_AUX, op_aux));
2827 STATIC_ASSERT_STMT( STRUCT_OFFSET(LISTOP, op_last)
2828 == STRUCT_OFFSET(UNOP_AUX, op_aux));
2829
2830 /* Now scan the down the tree looking for a series of
2831 * CONCAT/OPf_STACKED ops on the LHS (with the last one not
2832 * stacked). For example this tree:
2833 *
2834 * |
2835 * CONCAT/STACKED
2836 * |
2837 * CONCAT/STACKED -- EXPR5
2838 * |
2839 * CONCAT/STACKED -- EXPR4
2840 * |
2841 * CONCAT -- EXPR3
2842 * |
2843 * EXPR1 -- EXPR2
2844 *
2845 * corresponds to an expression like
2846 *
2847 * (EXPR1 . EXPR2 . EXPR3 . EXPR4 . EXPR5)
2848 *
2849 * Record info about each EXPR in args[]: in particular, whether it is
2850 * a stringifiable OP_CONST and if so what the const sv is.
2851 *
2852 * The reason why the last concat can't be STACKED is the difference
2853 * between
2854 *
2855 * ((($a .= $a) .= $a) .= $a) .= $a
2856 *
2857 * and
2858 * $a . $a . $a . $a . $a
2859 *
2860 * The main difference between the optrees for those two constructs
2861 * is the presence of the last STACKED. As well as modifying $a,
2862 * the former sees the changed $a between each concat, so if $s is
2863 * initially 'a', the first returns 'a' x 16, while the latter returns
2864 * 'a' x 5. And pp_multiconcat can't handle that kind of thing.
2865 */
2866
2867 kid = topop;
2868
2869 for (;;) {
2870 OP *argop;
2871 SV *sv;
2872 bool last = FALSE;
2873
2874 if ( kid->op_type == OP_CONCAT
2875 && !kid_is_last
2876 ) {
2877 OP *k1, *k2;
2878 k1 = cUNOPx(kid)->op_first;
2879 k2 = OpSIBLING(k1);
2880 /* shouldn't happen except maybe after compile err? */
2881 if (!k2)
2882 return;
2883
2884 /* avoid turning (A . B . ($lex = C) ...) into (A . B . C ...) */
2885 if (kid->op_private & OPpTARGET_MY)
2886 kid_is_last = TRUE;
2887
2888 stacked_last = (kid->op_flags & OPf_STACKED);
2889 if (!stacked_last)
2890 kid_is_last = TRUE;
2891
2892 kid = k1;
2893 argop = k2;
2894 }
2895 else {
2896 argop = kid;
2897 last = TRUE;
2898 }
2899
f08f2d03 2900 if ( nargs + nadjconst > PERL_MULTICONCAT_MAXARG - 2
e839e6ed
DM
2901 || (argp - args + 1) > (PERL_MULTICONCAT_MAXARG*2 + 1) - 2)
2902 {
2903 /* At least two spare slots are needed to decompose both
2904 * concat args. If there are no slots left, continue to
2905 * examine the rest of the optree, but don't push new values
2906 * on args[]. If the optree as a whole is legal for conversion
2907 * (in particular that the last concat isn't STACKED), then
2908 * the first PERL_MULTICONCAT_MAXARG elements of the optree
2909 * can be converted into an OP_MULTICONCAT now, with the first
2910 * child of that op being the remainder of the optree -
2911 * which may itself later be converted to a multiconcat op
2912 * too.
2913 */
2914 if (last) {
2915 /* the last arg is the rest of the optree */
2916 argp++->p = NULL;
2917 nargs++;
2918 }
2919 }
2920 else if ( argop->op_type == OP_CONST
2921 && ((sv = cSVOPx_sv(argop)))
2922 /* defer stringification until runtime of 'constant'
2923 * things that might stringify variantly, e.g. the radix
2924 * point of NVs, or overloaded RVs */
2925 && (SvPOK(sv) || SvIOK(sv))
2926 && (!SvGMAGICAL(sv))
2927 ) {
2928 argp++->p = sv;
2929 utf8 |= cBOOL(SvUTF8(sv));
2930 nconst++;
f08f2d03
DM
2931 if (prev_was_const)
2932 /* this const may be demoted back to a plain arg later;
2933 * make sure we have enough arg slots left */
2934 nadjconst++;
2935 prev_was_const = !prev_was_const;
e839e6ed
DM
2936 }
2937 else {
2938 argp++->p = NULL;
2939 nargs++;
f08f2d03 2940 prev_was_const = FALSE;
e839e6ed
DM
2941 }
2942
2943 if (last)
2944 break;
2945 }
2946
2947 toparg = argp - 1;
2948
2949 if (stacked_last)
2950 return; /* we don't support ((A.=B).=C)...) */
2951
bcc30fd0
DM
2952 /* look for two adjacent consts and don't fold them together:
2953 * $o . "a" . "b"
2954 * should do
2955 * $o->concat("a")->concat("b")
2956 * rather than
2957 * $o->concat("ab")
2958 * (but $o .= "a" . "b" should still fold)
2959 */
2960 {
2961 bool seen_nonconst = FALSE;
2962 for (argp = toparg; argp >= args; argp--) {
2963 if (argp->p == NULL) {
2964 seen_nonconst = TRUE;
2965 continue;
2966 }
2967 if (!seen_nonconst)
2968 continue;
2969 if (argp[1].p) {
2970 /* both previous and current arg were constants;
2971 * leave the current OP_CONST as-is */
2972 argp->p = NULL;
2973 nconst--;
2974 nargs++;
2975 }
2976 }
2977 }
2978
e839e6ed
DM
2979 /* -----------------------------------------------------------------
2980 * Phase 2:
2981 *
2982 * At this point we have determined that the optree *can* be converted
2983 * into a multiconcat. Having gathered all the evidence, we now decide
2984 * whether it *should*.
2985 */
2986
2987
2988 /* we need at least one concat action, e.g.:
2989 *
2990 * Y . Z
2991 * X = Y . Z
2992 * X .= Y
2993 *
2994 * otherwise we could be doing something like $x = "foo", which
2995 * if treated as as a concat, would fail to COW.
2996 */
2997 if (nargs + nconst + cBOOL(private_flags & OPpMULTICONCAT_APPEND) < 2)
2998 return;
2999
3000 /* Benchmarking seems to indicate that we gain if:
3001 * * we optimise at least two actions into a single multiconcat
3002 * (e.g concat+concat, sassign+concat);
3003 * * or if we can eliminate at least 1 OP_CONST;
3004 * * or if we can eliminate a padsv via OPpTARGET_MY
3005 */
3006
3007 if (
3008 /* eliminated at least one OP_CONST */
3009 nconst >= 1
3010 /* eliminated an OP_SASSIGN */
3011 || o->op_type == OP_SASSIGN
3012 /* eliminated an OP_PADSV */
3013 || (!targmyop && is_targable)
3014 )
3015 /* definitely a net gain to optimise */
3016 goto optimise;
3017
3018 /* ... if not, what else? */
3019
3020 /* special-case '$lex1 = expr . $lex1' (where expr isn't lex1):
3021 * multiconcat is faster (due to not creating a temporary copy of
3022 * $lex1), whereas for a general $lex1 = $lex2 . $lex3, concat is
3023 * faster.
3024 */
3025 if ( nconst == 0
3026 && nargs == 2
3027 && targmyop
3028 && topop->op_type == OP_CONCAT
3029 ) {
3030 PADOFFSET t = targmyop->op_targ;
3031 OP *k1 = cBINOPx(topop)->op_first;
3032 OP *k2 = cBINOPx(topop)->op_last;
3033 if ( k2->op_type == OP_PADSV
3034 && k2->op_targ == t
3035 && ( k1->op_type != OP_PADSV
3036 || k1->op_targ != t)
3037 )
3038 goto optimise;
3039 }
3040
3041 /* need at least two concats */
3042 if (nargs + nconst + cBOOL(private_flags & OPpMULTICONCAT_APPEND) < 3)
3043 return;
3044
3045
3046
3047 /* -----------------------------------------------------------------
3048 * Phase 3:
3049 *
3050 * At this point the optree has been verified as ok to be optimised
3051 * into an OP_MULTICONCAT. Now start changing things.
3052 */
3053
3054 optimise:
3055
3056 /* stringify all const args and determine utf8ness */
3057
3058 variant = 0;
3059 for (argp = args; argp <= toparg; argp++) {
3060 SV *sv = (SV*)argp->p;
3061 if (!sv)
3062 continue; /* not a const op */
3063 if (utf8 && !SvUTF8(sv))
3064 sv_utf8_upgrade_nomg(sv);
3065 argp->p = SvPV_nomg(sv, argp->len);
3066 total_len += argp->len;
3067
3068 /* see if any strings would grow if converted to utf8 */
3069 if (!utf8) {
3070 char *p = (char*)argp->p;
3071 STRLEN len = argp->len;
3072 while (len--) {
3073 U8 c = *p++;
3074 if (!UTF8_IS_INVARIANT(c))
3075 variant++;
3076 }
3077 }
3078 }
3079
3080 /* create and populate aux struct */
3081
3082 create_aux:
3083
3084 aux = (UNOP_AUX_item*)PerlMemShared_malloc(
3085 sizeof(UNOP_AUX_item)
3086 * (
3087 PERL_MULTICONCAT_HEADER_SIZE
3088 + ((nargs + 1) * (variant ? 2 : 1))
3089 )
3090 );
6623aa6a 3091 const_str = (char *)PerlMemShared_malloc(total_len ? total_len : 1);
e839e6ed
DM
3092
3093 /* Extract all the non-const expressions from the concat tree then
3094 * dispose of the old tree, e.g. convert the tree from this:
3095 *
3096 * o => SASSIGN
3097 * |
3098 * STRINGIFY -- TARGET
3099 * |
3100 * ex-PUSHMARK -- CONCAT
3101 * |
3102 * CONCAT -- EXPR5
3103 * |
3104 * CONCAT -- EXPR4
3105 * |
3106 * CONCAT -- EXPR3
3107 * |
3108 * EXPR1 -- EXPR2
3109 *
3110 *
3111 * to:
3112 *
3113 * o => MULTICONCAT
3114 * |
3115 * ex-PUSHMARK -- EXPR1 -- EXPR2 -- EXPR3 -- EXPR4 -- EXPR5 -- TARGET
3116 *
3117 * except that if EXPRi is an OP_CONST, it's discarded.
3118 *
3119 * During the conversion process, EXPR ops are stripped from the tree
3120 * and unshifted onto o. Finally, any of o's remaining original
3121 * childen are discarded and o is converted into an OP_MULTICONCAT.
3122 *
3123 * In this middle of this, o may contain both: unshifted args on the
3124 * left, and some remaining original args on the right. lastkidop
3125 * is set to point to the right-most unshifted arg to delineate
3126 * between the two sets.
3127 */
3128
3129
3130 if (is_sprintf) {
3131 /* create a copy of the format with the %'s removed, and record
3132 * the sizes of the const string segments in the aux struct */
3133 char *q, *oldq;
3134 lenp = aux + PERL_MULTICONCAT_IX_LENGTHS;
3135
3136 p = sprintf_info.start;
3137 q = const_str;
3138 oldq = q;
3139 for (; p < sprintf_info.end; p++) {
3140 if (*p == '%') {
3141 p++;
3142 if (*p != '%') {
b5bf9f73 3143 (lenp++)->ssize = q - oldq;
e839e6ed
DM
3144 oldq = q;
3145 continue;
3146 }
3147 }
3148 *q++ = *p;
3149 }
b5bf9f73 3150 lenp->ssize = q - oldq;
e839e6ed
DM
3151 assert((STRLEN)(q - const_str) == total_len);
3152
3153 /* Attach all the args (i.e. the kids of the sprintf) to o (which
3154 * may or may not be topop) The pushmark and const ops need to be
3155 * kept in case they're an op_next entry point.
3156 */
3157 lastkidop = cLISTOPx(topop)->op_last;
3158 kid = cUNOPx(topop)->op_first; /* pushmark */
3159 op_null(kid);
3160 op_null(OpSIBLING(kid)); /* const */
3161 if (o != topop) {
3162 kid = op_sibling_splice(topop, NULL, -1, NULL); /* cut all args */
3163 op_sibling_splice(o, NULL, 0, kid); /* and attach to o */
3164 lastkidop->op_next = o;
3165 }
3166 }
3167 else {
3168 p = const_str;
3169 lenp = aux + PERL_MULTICONCAT_IX_LENGTHS;
3170
b5bf9f73 3171 lenp->ssize = -1;
e839e6ed
DM
3172
3173 /* Concatenate all const strings into const_str.
3174 * Note that args[] contains the RHS args in reverse order, so
3175 * we scan args[] from top to bottom to get constant strings
3176 * in L-R order
3177 */
3178 for (argp = toparg; argp >= args; argp--) {
3179 if (!argp->p)
3180 /* not a const op */
b5bf9f73 3181 (++lenp)->ssize = -1;
e839e6ed
DM
3182 else {
3183 STRLEN l = argp->len;
3184 Copy(argp->p, p, l, char);
3185 p += l;
b5bf9f73
DM
3186 if (lenp->ssize == -1)
3187 lenp->ssize = l;
e839e6ed 3188 else
b5bf9f73 3189 lenp->ssize += l;
e839e6ed
DM
3190 }
3191 }
3192
3193 kid = topop;
3194 nextop = o;
3195 lastkidop = NULL;
3196
3197 for (argp = args; argp <= toparg; argp++) {
3198 /* only keep non-const args, except keep the first-in-next-chain
3199 * arg no matter what it is (but nulled if OP_CONST), because it
3200 * may be the entry point to this subtree from the previous
3201 * op_next.
3202 */
3203 bool last = (argp == toparg);
3204 OP *prev;
3205
3206 /* set prev to the sibling *before* the arg to be cut out,
3207 * e.g.:
3208 *
3209 * |
3210 * kid= CONST
3211 * |
3212 * prev= CONST -- EXPR
3213 * |
3214 */
3215 if (argp == args && kid->op_type != OP_CONCAT) {
3216 /* in e.g. '$x . = f(1)' there's no RHS concat tree
3217 * so the expression to be cut isn't kid->op_last but
3218 * kid itself */
3219 OP *o1, *o2;
3220 /* find the op before kid */
3221 o1 = NULL;
3222 o2 = cUNOPx(parentop)->op_first;
3223 while (o2 && o2 != kid) {
3224 o1 = o2;
3225 o2 = OpSIBLING(o2);
3226 }
3227 assert(o2 == kid);
3228 prev = o1;
3229 kid = parentop;
3230 }
3231 else if (kid == o && lastkidop)
3232 prev = last ? lastkidop : OpSIBLING(lastkidop);
3233 else
3234 prev = last ? NULL : cUNOPx(kid)->op_first;
3235
3236 if (!argp->p || last) {
3237 /* cut RH op */
3238 OP *aop = op_sibling_splice(kid, prev, 1, NULL);
3239 /* and unshift to front of o */
3240 op_sibling_splice(o, NULL, 0, aop);
3241 /* record the right-most op added to o: later we will
3242 * free anything to the right of it */
3243 if (!lastkidop)
3244 lastkidop = aop;
3245 aop->op_next = nextop;
3246 if (last) {
3247 if (argp->p)
3248 /* null the const at start of op_next chain */
3249 op_null(aop);
3250 }
3251 else if (prev)
3252 nextop = prev->op_next;
3253 }
3254
3255 /* the last two arguments are both attached to the same concat op */
3256 if (argp < toparg - 1)
3257 kid = prev;
3258 }
3259 }
3260
3261 /* Populate the aux struct */
3262
ca84e88e 3263 aux[PERL_MULTICONCAT_IX_NARGS].ssize = nargs;
e839e6ed 3264 aux[PERL_MULTICONCAT_IX_PLAIN_PV].pv = utf8 ? NULL : const_str;
b5bf9f73 3265 aux[PERL_MULTICONCAT_IX_PLAIN_LEN].ssize = utf8 ? 0 : total_len;
e839e6ed 3266 aux[PERL_MULTICONCAT_IX_UTF8_PV].pv = const_str;
b5bf9f73 3267 aux[PERL_MULTICONCAT_IX_UTF8_LEN].ssize = total_len;
e839e6ed
DM
3268
3269 /* if variant > 0, calculate a variant const string and lengths where
3270 * the utf8 version of the string will take 'variant' more bytes than
3271 * the plain one. */
3272
3273 if (variant) {
3274 char *p = const_str;
3275 STRLEN ulen = total_len + variant;
3276 UNOP_AUX_item *lens = aux + PERL_MULTICONCAT_IX_LENGTHS;
3277 UNOP_AUX_item *ulens = lens + (nargs + 1);
3278 char *up = (char*)PerlMemShared_malloc(ulen);
ca84e88e 3279 SSize_t n;
e839e6ed
DM
3280
3281 aux[PERL_MULTICONCAT_IX_UTF8_PV].pv = up;
b5bf9f73 3282 aux[PERL_MULTICONCAT_IX_UTF8_LEN].ssize = ulen;
e839e6ed
DM
3283
3284 for (n = 0; n < (nargs + 1); n++) {
576915da
DM
3285 SSize_t i;
3286 char * orig_up = up;
b5bf9f73 3287 for (i = (lens++)->ssize; i > 0; i--) {
e839e6ed 3288 U8 c = *p++;
576915da 3289 append_utf8_from_native_byte(c, (U8**)&up);
e839e6ed 3290 }
b5bf9f73 3291 (ulens++)->ssize = (i < 0) ? i : up - orig_up;
e839e6ed
DM
3292 }
3293 }
3294
3295 if (stringop) {
3296 /* if there was a top(ish)-level OP_STRINGIFY, we need to keep
3297 * that op's first child - an ex-PUSHMARK - because the op_next of
3298 * the previous op may point to it (i.e. it's the entry point for
3299 * the o optree)
3300 */
3301 OP *pmop =
3302 (stringop == o)
3303 ? op_sibling_splice(o, lastkidop, 1, NULL)
3304 : op_sibling_splice(stringop, NULL, 1, NULL);
3305 assert(OP_TYPE_IS_OR_WAS_NN(pmop, OP_PUSHMARK));
3306 op_sibling_splice(o, NULL, 0, pmop);
3307 if (!lastkidop)
3308 lastkidop = pmop;
3309 }
3310
3311 /* Optimise
3312 * target = A.B.C...
3313 * target .= A.B.C...
3314 */
3315
3316 if (targetop) {
3317 assert(!targmyop);
3318
3319 if (o->op_type == OP_SASSIGN) {
3320 /* Move the target subtree from being the last of o's children
3321 * to being the last of o's preserved children.
3322 * Note the difference between 'target = ...' and 'target .= ...':
3323 * for the former, target is executed last; for the latter,
3324 * first.
3325 */
3326 kid = OpSIBLING(lastkidop);
3327 op_sibling_splice(o, kid, 1, NULL); /* cut target op */
3328 op_sibling_splice(o, lastkidop, 0, targetop); /* and paste */
3329 lastkidop->op_next = kid->op_next;
3330 lastkidop = targetop;
3331 }
3332 else {
3333 /* Move the target subtree from being the first of o's
3334 * original children to being the first of *all* o's children.
3335 */
3336 if (lastkidop) {
3337 op_sibling_splice(o, lastkidop, 1, NULL); /* cut target op */
3338 op_sibling_splice(o, NULL, 0, targetop); /* and paste*/
3339 }
3340 else {
3341 /* if the RHS of .= doesn't contain a concat (e.g.
3342 * $x .= "foo"), it gets missed by the "strip ops from the
3343 * tree and add to o" loop earlier */
3344 assert(topop->op_type != OP_CONCAT);
3345 if (stringop) {
3346 /* in e.g. $x .= "$y", move the $y expression
3347 * from being a child of OP_STRINGIFY to being the
3348 * second child of the OP_CONCAT
3349 */
3350 assert(cUNOPx(stringop)->op_first == topop);
3351 op_sibling_splice(stringop, NULL, 1, NULL);
3352 op_sibling_splice(o, cUNOPo->op_first, 0, topop);
3353 }
3354 assert(topop == OpSIBLING(cBINOPo->op_first));
3355 if (toparg->p)
3356 op_null(topop);
3357 lastkidop = topop;
3358 }
3359 }
3360
3361 if (is_targable) {
3362 /* optimise
3363 * my $lex = A.B.C...
3364 * $lex = A.B.C...
3365 * $lex .= A.B.C...
3366 * The original padsv op is kept but nulled in case it's the
3367 * entry point for the optree (which it will be for
3368 * '$lex .= ... '
3369 */
3370 private_flags |= OPpTARGET_MY;
3371 private_flags |= (targetop->op_private & OPpLVAL_INTRO);
3372 o->op_targ = targetop->op_targ;
3373 targetop->op_targ = 0;
3374 op_null(targetop);
3375 }
3376 else
3377 flags |= OPf_STACKED;
3378 }
3379 else if (targmyop) {
3380 private_flags |= OPpTARGET_MY;
3381 if (o != targmyop) {
3382 o->op_targ = targmyop->op_targ;
3383 targmyop->op_targ = 0;
3384 }
3385 }
3386
3387 /* detach the emaciated husk of the sprintf/concat optree and free it */
3388 for (;;) {
3389 kid = op_sibling_splice(o, lastkidop, 1, NULL);
3390 if (!kid)
3391 break;
3392 op_free(kid);
3393 }
3394
3395 /* and convert o into a multiconcat */
3396
3397 o->op_flags = (flags|OPf_KIDS|stacked_last
3398 |(o->op_flags & (OPf_WANT|OPf_PARENS)));
3399 o->op_private = private_flags;
3400 o->op_type = OP_MULTICONCAT;
3401 o->op_ppaddr = PL_ppaddr[OP_MULTICONCAT];
3402 cUNOP_AUXo->op_aux = aux;
3403}
3404
12ee5d32 3405
01f9673f
DM
3406/* do all the final processing on an optree (e.g. running the peephole
3407 * optimiser on it), then attach it to cv (if cv is non-null)
3408 */
3409
3410static void
3411S_process_optree(pTHX_ CV *cv, OP *optree, OP* start)
3412{
3413 OP **startp;
3414
3415 /* XXX for some reason, evals, require and main optrees are
3416 * never attached to their CV; instead they just hang off
3417 * PL_main_root + PL_main_start or PL_eval_root + PL_eval_start
3418 * and get manually freed when appropriate */
3419 if (cv)
3420 startp = &CvSTART(cv);
3421 else
3422 startp = PL_in_eval? &PL_eval_start : &PL_main_start;
3423
3424 *startp = start;
3425 optree->op_private |= OPpREFCOUNTED;
3426 OpREFCNT_set(optree, 1);
d2905138 3427 optimize_optree(optree);
01f9673f
DM
3428 CALL_PEEP(*startp);
3429 finalize_optree(optree);
3430 S_prune_chain_head(startp);
3431
3432 if (cv) {
3433 /* now that optimizer has done its work, adjust pad values */
3434 pad_tidy(optree->op_type == OP_LEAVEWRITE ? padtidy_FORMAT
3435 : CvCLONE(cv) ? padtidy_SUBCLONE : padtidy_SUB);
3436 }
3437}
3438
3439
3ad73efd 3440/*
d2905138
DM
3441=for apidoc optimize_optree
3442
3443This function applies some optimisations to the optree in top-down order.
3444It is called before the peephole optimizer, which processes ops in
3445execution order. Note that finalize_optree() also does a top-down scan,
3446but is called *after* the peephole optimizer.
3447
3448=cut
3449*/
3450
3451void
3452Perl_optimize_optree(pTHX_ OP* o)
3453{
3454 PERL_ARGS_ASSERT_OPTIMIZE_OPTREE;
3455
3456 ENTER;
3457 SAVEVPTR(PL_curcop);
3458
3459 optimize_op(o);
3460
3461 LEAVE;
3462}
3463
3464
3465/* helper for optimize_optree() which optimises on op then recurses
3466 * to optimise any children.
3467 */
3468
3469STATIC void
3470S_optimize_op(pTHX_ OP* o)
3471{
3472 OP *kid;
3473
3474 PERL_ARGS_ASSERT_OPTIMIZE_OP;
3475 assert(o->op_type != OP_FREED);
3476
3477 switch (o->op_type) {
3478 case OP_NEXTSTATE:
3479 case OP_DBSTATE:
3480 PL_curcop = ((COP*)o); /* for warnings */
3481 break;
3482
3483
e839e6ed
DM
3484 case OP_CONCAT:
3485 case OP_SASSIGN:
3486 case OP_STRINGIFY:
3487 case OP_SPRINTF:
3488 S_maybe_multiconcat(aTHX_ o);
3489 break;
3490
d2905138
DM
3491 case OP_SUBST:
3492 if (cPMOPo->op_pmreplrootu.op_pmreplroot)
3493 optimize_op(cPMOPo->op_pmreplrootu.op_pmreplroot);
3494 break;
3495
3496 default:
3497 break;
3498 }
3499
3500 if (!(o->op_flags & OPf_KIDS))
3501 return;
3502
3503 for (kid = cUNOPo->op_first; kid; kid = OpSIBLING(kid))
3504 optimize_op(kid);
3505}
3506
3507
3508/*
d164302a
GG
3509=for apidoc finalize_optree
3510
72d33970
FC
3511This function finalizes the optree. Should be called directly after
3512the complete optree is built. It does some additional
796b6530 3513checking which can't be done in the normal C<ck_>xxx functions and makes
d164302a
GG
3514the tree thread-safe.
3515
3516=cut
3517*/
3518void
3519Perl_finalize_optree(pTHX_ OP* o)
3520{
3521 PERL_ARGS_ASSERT_FINALIZE_OPTREE;
3522
3523 ENTER;
3524 SAVEVPTR(PL_curcop);
3525
3526 finalize_op(o);
3527
3528 LEAVE;
3529}
3530
b46e009d 3531#ifdef USE_ITHREADS
3532/* Relocate sv to the pad for thread safety.
3533 * Despite being a "constant", the SV is written to,
3534 * for reference counts, sv_upgrade() etc. */
3535PERL_STATIC_INLINE void
3536S_op_relocate_sv(pTHX_ SV** svp, PADOFFSET* targp)
3537{
3538 PADOFFSET ix;
3539 PERL_ARGS_ASSERT_OP_RELOCATE_SV;
3540 if (!*svp) return;
3541 ix = pad_alloc(OP_CONST, SVf_READONLY);
3542 SvREFCNT_dec(PAD_SVl(ix));
3543 PAD_SETSV(ix, *svp);
3544 /* XXX I don't know how this isn't readonly already. */
3545 if (!SvIsCOW(PAD_SVl(ix))) SvREADONLY_on(PAD_SVl(ix));
3546 *svp = NULL;
3547 *targp = ix;
3548}
3549#endif
3550
3551
60dde6b2 3552STATIC void
d164302a
GG
3553S_finalize_op(pTHX_ OP* o)
3554{
3555 PERL_ARGS_ASSERT_FINALIZE_OP;
3556
68d1ee85 3557 assert(o->op_type != OP_FREED);
d164302a
GG
3558
3559 switch (o->op_type) {
3560 case OP_NEXTSTATE:
3561 case OP_DBSTATE:
3562 PL_curcop = ((COP*)o); /* for warnings */
3563 break;
3564 case OP_EXEC:
e6dae479
FC
3565 if (OpHAS_SIBLING(o)) {
3566 OP *sib = OpSIBLING(o);
1ed44841
DM
3567 if (( sib->op_type == OP_NEXTSTATE || sib->op_type == OP_DBSTATE)
3568 && ckWARN(WARN_EXEC)
e6dae479 3569 && OpHAS_SIBLING(sib))
1ed44841 3570 {
e6dae479 3571 const OPCODE type = OpSIBLING(sib)->op_type;
d164302a
GG
3572 if (type != OP_EXIT && type != OP_WARN && type != OP_DIE) {
3573 const line_t oldline = CopLINE(PL_curcop);
1ed44841 3574 CopLINE_set(PL_curcop, CopLINE((COP*)sib));
d164302a
GG
3575 Perl_warner(aTHX_ packWARN(WARN_EXEC),
3576 "Statement unlikely to be reached");
3577 Perl_warner(aTHX_ packWARN(WARN_EXEC),
3578 "\t(Maybe you meant system() when you said exec()?)\n");
3579 CopLINE_set(PL_curcop, oldline);
3580 }
d164302a 3581 }
1ed44841 3582 }
d164302a
GG
3583 break;
3584
3585 case OP_GV:
3586 if ((o->op_private & OPpEARLY_CV) && ckWARN(WARN_PROTOTYPE)) {
3587 GV * const gv = cGVOPo_gv;
3588 if (SvTYPE(gv) == SVt_PVGV && GvCV(gv) && SvPVX_const(GvCV(gv))) {
3589 /* XXX could check prototype here instead of just carping */
3590 SV * const sv = sv_newmortal();
3591 gv_efullname3(sv, gv, NULL);
3592 Perl_warner(aTHX_ packWARN(WARN_PROTOTYPE),
147e3846 3593 "%" SVf "() called too early to check prototype",
d164302a
GG
3594 SVfARG(sv));
3595 }
3596 }
3597 break;
3598
3599 case OP_CONST:
eb796c7f
GG
3600 if (cSVOPo->op_private & OPpCONST_STRICT)
3601 no_bareword_allowed(o);
d164302a 3602#ifdef USE_ITHREADS
146930d1 3603 /* FALLTHROUGH */
d164302a 3604 case OP_HINTSEVAL:
b46e009d 3605 op_relocate_sv(&cSVOPo->op_sv, &o->op_targ);
3606#endif
3607 break;
3608
3609#ifdef USE_ITHREADS
3610 /* Relocate all the METHOP's SVs to the pad for thread safety. */
d164302a 3611 case OP_METHOD_NAMED:
7d6c333c 3612 case OP_METHOD_SUPER:
810bd8b7 3613 case OP_METHOD_REDIR:
3614 case OP_METHOD_REDIR_SUPER:
b46e009d 3615 op_relocate_sv(&cMETHOPx(o)->op_u.op_meth_sv, &o->op_targ);
3616 break;
d164302a 3617#endif
d164302a
GG
3618
3619 case OP_HELEM: {
3620 UNOP *rop;
565e6f7e
FC
3621 SVOP *key_op;
3622 OP *kid;
d164302a 3623
565e6f7e 3624 if ((key_op = cSVOPx(((BINOP*)o)->op_last))->op_type != OP_CONST)
d164302a
GG
3625 break;
3626
3627 rop = (UNOP*)((BINOP*)o)->op_first;
e6307ed0 3628
565e6f7e 3629 goto check_keys;
d164302a 3630
565e6f7e 3631 case OP_HSLICE:
429a2555 3632 S_scalar_slice_warning(aTHX_ o);
c67159e1 3633 /* FALLTHROUGH */
429a2555 3634
c5f75dba 3635 case OP_KVHSLICE:
e6dae479 3636 kid = OpSIBLING(cLISTOPo->op_first);
71323522 3637 if (/* I bet there's always a pushmark... */
7d3c8a68
SM
3638 OP_TYPE_ISNT_AND_WASNT_NN(kid, OP_LIST)
3639 && OP_TYPE_ISNT_NN(kid, OP_CONST))
3640 {
d164302a 3641 break;
7d3c8a68 3642 }
565e6f7e
FC
3643
3644 key_op = (SVOP*)(kid->op_type == OP_CONST
3645 ? kid
e6dae479 3646 : OpSIBLING(kLISTOP->op_first));
565e6f7e
FC
3647
3648 rop = (UNOP*)((LISTOP*)o)->op_last;
3649
3650 check_keys:
12ee5d32
DM
3651 if (o->op_private & OPpLVAL_INTRO || rop->op_type != OP_RV2HV)
3652 rop = NULL;
fedf30e1 3653 S_check_hash_fields_and_hekify(aTHX_ rop, key_op);
d164302a
GG
3654 break;
3655 }
fe7df09e
FC
3656 case OP_NULL:
3657 if (o->op_targ != OP_HSLICE && o->op_targ != OP_ASLICE)
3658 break;
3659 /* FALLTHROUGH */
429a2555
FC
3660 case OP_ASLICE:
3661 S_scalar_slice_warning(aTHX_ o);
3662 break;
a7fd8ef6 3663
d164302a
GG
3664 case OP_SUBST: {
3665 if (cPMOPo->op_pmreplrootu.op_pmreplroot)
3666 finalize_op(cPMOPo->op_pmreplrootu.op_pmreplroot);
3667 break;
3668 }
3669 default:
3670 break;
3671 }
3672
3673 if (o->op_flags & OPf_KIDS) {
3674 OP *kid;
c4b20975
DM
3675
3676#ifdef DEBUGGING
20220689 3677 /* check that op_last points to the last sibling, and that
86cd3a13
DM
3678 * the last op_sibling/op_sibparent field points back to the
3679 * parent, and that the only ops with KIDS are those which are
3680 * entitled to them */
c4b20975
DM
3681 U32 type = o->op_type;
3682 U32 family;
20220689 3683 bool has_last;
c4b20975
DM
3684
3685 if (type == OP_NULL) {
3686 type = o->op_targ;
3687 /* ck_glob creates a null UNOP with ex-type GLOB
3688 * (which is a list op. So pretend it wasn't a listop */
3689 if (type == OP_GLOB)
3690 type = OP_NULL;
3691 }
3692 family = PL_opargs[type] & OA_CLASS_MASK;
3693
20220689
DM
3694 has_last = ( family == OA_BINOP
3695 || family == OA_LISTOP
3696 || family == OA_PMOP
3697 || family == OA_LOOP
3698 );
3699 assert( has_last /* has op_first and op_last, or ...
3700 ... has (or may have) op_first: */
3701 || family == OA_UNOP
2f7c6295 3702 || family == OA_UNOP_AUX
20220689
DM
3703 || family == OA_LOGOP
3704 || family == OA_BASEOP_OR_UNOP
3705 || family == OA_FILESTATOP
3706 || family == OA_LOOPEXOP
b46e009d 3707 || family == OA_METHOP
20220689
DM
3708 || type == OP_CUSTOM
3709 || type == OP_NULL /* new_logop does this */
3710 );
20220689 3711
e6dae479 3712 for (kid = cUNOPo->op_first; kid; kid = OpSIBLING(kid)) {
29e61fd9 3713# ifdef PERL_OP_PARENT
e6dae479 3714 if (!OpHAS_SIBLING(kid)) {
20220689 3715 if (has_last)
29e61fd9 3716 assert(kid == cLISTOPo->op_last);
86cd3a13 3717 assert(kid->op_sibparent == o);
20220689 3718 }
29e61fd9 3719# else
35a2929b 3720 if (has_last && !OpHAS_SIBLING(kid))
93059c1a 3721 assert(kid == cLISTOPo->op_last);
20220689 3722# endif
c4b20975
DM
3723 }
3724#endif
3725
e6dae479 3726 for (kid = cUNOPo->op_first; kid; kid = OpSIBLING(kid))
d164302a
GG
3727 finalize_op(kid);
3728 }
3729}
3730
3731/*
3ad73efd
Z
3732=for apidoc Amx|OP *|op_lvalue|OP *o|I32 type
3733
3734Propagate lvalue ("modifiable") context to an op and its children.
2d7f6611 3735C<type> represents the context type, roughly based on the type of op that
796b6530 3736would do the modifying, although C<local()> is represented by C<OP_NULL>,
3ad73efd 3737because it has no op type of its own (it is signalled by a flag on
001c3c51
FC
3738the lvalue op).
3739
3740This function detects things that can't be modified, such as C<$x+1>, and
72d33970 3741generates errors for them. For example, C<$x+1 = 2> would cause it to be
796b6530 3742called with an op of type C<OP_ADD> and a C<type> argument of C<OP_SASSIGN>.
001c3c51
FC
3743
3744It also flags things that need to behave specially in an lvalue context,
3745such as C<$$x = 5> which might have to vivify a reference in C<$x>.
3ad73efd
Z
3746
3747=cut
3748*/
ddeae0f1 3749
03414f05
FC
3750static void
3751S_mark_padname_lvalue(pTHX_ PADNAME *pn)
3752{
3753 CV *cv = PL_compcv;
3754 PadnameLVALUE_on(pn);
3755 while (PadnameOUTER(pn) && PARENT_PAD_INDEX(pn)) {
3756 cv = CvOUTSIDE(cv);
aea0412a
DM
3757 /* RT #127786: cv can be NULL due to an eval within the DB package
3758 * called from an anon sub - anon subs don't have CvOUTSIDE() set
3759 * unless they contain an eval, but calling eval within DB
3760 * pretends the eval was done in the caller's scope.
3761 */
3762 if (!cv)
3763 break;
03414f05
FC
3764 assert(CvPADLIST(cv));
3765 pn =
3766 PadlistNAMESARRAY(CvPADLIST(cv))[PARENT_PAD_INDEX(pn)];
3767 assert(PadnameLEN(pn));
3768 PadnameLVALUE_on(pn);
3769 }
3770}
3771
375879aa
FC
3772static bool
3773S_vivifies(const OPCODE type)
3774{
3775 switch(type) {
3776 case OP_RV2AV: case OP_ASLICE:
3777 case OP_RV2HV: case OP_KVASLICE:
3778 case OP_RV2SV: case OP_HSLICE:
3779 case OP_AELEMFAST: case OP_KVHSLICE:
3780 case OP_HELEM:
3781 case OP_AELEM:
3782 return 1;
3783 }
3784 return 0;
3785}
3786
7664512e 3787static void
63702de8 3788S_lvref(pTHX_ OP *o, I32 type)
7664512e 3789{
727d2dc6 3790 dVAR;
7664512e
FC
3791 OP *kid;
3792 switch (o->op_type) {
3793 case OP_COND_EXPR:
e6dae479
FC
3794 for (kid = OpSIBLING(cUNOPo->op_first); kid;
3795 kid = OpSIBLING(kid))
63702de8 3796 S_lvref(aTHX_ kid, type);
7664512e
FC
3797 /* FALLTHROUGH */
3798 case OP_PUSHMARK:
3799 return;
3800 case OP_RV2AV:
3801 if (cUNOPo->op_first->op_type != OP_GV) goto badref;
3802 o->op_flags |= OPf_STACKED;
3803 if (o->op_flags & OPf_PARENS) {
3804 if (o->op_private & OPpLVAL_INTRO) {
7664512e
FC
3805 yyerror(Perl_form(aTHX_ "Can't modify reference to "
3806 "localized parenthesized array in list assignment"));
3807 return;
3808 }
3809 slurpy:
b9a07097 3810 OpTYPE_set(o, OP_LVAVREF);
7664512e
FC
3811 o->op_private &= OPpLVAL_INTRO|OPpPAD_STATE;
3812 o->op_flags |= OPf_MOD|OPf_REF;
3813 return;
3814 }
3815 o->op_private |= OPpLVREF_AV;
3816 goto checkgv;
408e9044 3817 case OP_RV2CV:
19abb1ea
FC
3818 kid = cUNOPo->op_first;
3819 if (kid->op_type == OP_NULL)
cb748240 3820 kid = cUNOPx(OpSIBLING(kUNOP->op_first))
408e9044
FC
3821 ->op_first;
3822 o->op_private = OPpLVREF_CV;
3823 if (kid->op_type == OP_GV)
3824 o->op_flags |= OPf_STACKED;
3825 else if (kid->op_type == OP_PADCV) {
3826 o->op_targ = kid->op_targ;
3827 kid->op_targ = 0;
3828 op_free(cUNOPo->op_first);
3829 cUNOPo->op_first = NULL;
3830 o->op_flags &=~ OPf_KIDS;
3831 }
3832 else goto badref;
3833 break;
7664512e
FC
3834 case OP_RV2HV:
3835 if (o->op_flags & OPf_PARENS) {
3836 parenhash:
7664512e
FC
3837 yyerror(Perl_form(aTHX_ "Can't modify reference to "
3838 "parenthesized hash in list assignment"));
3839 return;
3840 }
3841 o->op_private |= OPpLVREF_HV;
3842 /* FALLTHROUGH */
3843 case OP_RV2SV:
3844 checkgv:
3845 if (cUNOPo->op_first->op_type != OP_GV) goto badref;
3846 o->op_flags |= OPf_STACKED;
6f5dab3c
FC
3847 break;
3848 case OP_PADHV:
3849 if (o->op_flags & OPf_PARENS) goto parenhash;
3850 o->op_private |= OPpLVREF_HV;
7664512e
FC
3851 /* FALLTHROUGH */
3852 case OP_PADSV:
6f5dab3c 3853 PAD_COMPNAME_GEN_set(o->op_targ, PERL_INT_MAX);
7664512e
FC
3854 break;
3855 case OP_PADAV:
6f5dab3c 3856 PAD_COMPNAME_GEN_set(o->op_targ, PERL_INT_MAX);
7664512e
FC
3857 if (o->op_flags & OPf_PARENS) goto slurpy;
3858 o->op_private |= OPpLVREF_AV;
3859 break;
7664512e
FC
3860 case OP_AELEM:
3861 case OP_HELEM:
3862 o->op_private |= OPpLVREF_ELEM;
3863 o->op_flags |= OPf_STACKED;
3864 break;
3865 case OP_ASLICE:
3866 case OP_HSLICE:
b9a07097 3867 OpTYPE_set(o, OP_LVREFSLICE);
36efb5a6 3868 o->op_private &= OPpLVAL_INTRO;
7664512e
FC
3869 return;
3870 case OP_NULL:
3871 if (o->op_flags & OPf_SPECIAL) /* do BLOCK */
3872 goto badref;
3873 else if (!(o->op_flags & OPf_KIDS))
3874 return;
3875 if (o->op_targ != OP_LIST) {
63702de8 3876 S_lvref(aTHX_ cBINOPo->op_first, type);
7664512e
FC
3877 return;
3878 }
3879 /* FALLTHROUGH */
3880 case OP_LIST:
e6dae479 3881 for (kid = cLISTOPo->op_first; kid; kid = OpSIBLING(kid)) {
7664512e 3882 assert((kid->op_flags & OPf_WANT) != OPf_WANT_VOID);
63702de8 3883 S_lvref(aTHX_ kid, type);
7664512e
FC
3884 }
3885 return;
3886 case OP_STUB:
3887 if (o->op_flags & OPf_PARENS)
3888 return;
3889 /* FALLTHROUGH */
3890 default:
3891 badref:
cf6e1fa1 3892 /* diag_listed_as: Can't modify reference to %s in %s assignment */
63702de8 3893 yyerror(Perl_form(aTHX_ "Can't modify reference to %s in %s",
7664512e
FC
3894 o->op_type == OP_NULL && o->op_flags & OPf_SPECIAL
3895 ? "do block"
63702de8
FC
3896 : OP_DESC(o),
3897 PL_op_desc[type]));
2b6a5bfb 3898 return;
7664512e 3899 }
b9a07097 3900 OpTYPE_set(o, OP_LVREF);
3ad7d304
FC
3901 o->op_private &=
3902 OPpLVAL_INTRO|OPpLVREF_ELEM|OPpLVREF_TYPE|OPpPAD_STATE;
d39c26a6
FC
3903 if (type == OP_ENTERLOOP)
3904 o->op_private |= OPpLVREF_ITER;
7664512e
FC
3905}
3906
1a3e9724
FC
3907PERL_STATIC_INLINE bool
3908S_potential_mod_type(I32 type)
3909{
3910 /* Types that only potentially result in modification. */
3911 return type == OP_GREPSTART || type == OP_ENTERSUB
3912 || type == OP_REFGEN || type == OP_LEAVESUBLV;
3913}
3914
79072805 3915OP *
d3d7d28f 3916Perl_op_lvalue_flags(pTHX_ OP *o, I32 type, U32 flags)
79072805 3917{
27da23d5 3918 dVAR;
79072805 3919 OP *kid;
ddeae0f1
DM
3920 /* -1 = error on localize, 0 = ignore localize, 1 = ok to localize */
3921 int localize = -1;
79072805 3922
13765c85 3923 if (!o || (PL_parser && PL_parser->error_count))
11343788 3924 return o;
79072805 3925
b162f9ea 3926 if ((o->op_private & OPpTARGET_MY)
7e363e51
GS
3927 && (PL_opargs[o->op_type] & OA_TARGLEX))/* OPp share the meaning */
3928 {
b162f9ea 3929 return o;
7e363e51 3930 }
1c846c1f 3931
5c906035
GG
3932 assert( (o->op_flags & OPf_WANT) != OPf_WANT_VOID );
3933
69974ce6
FC
3934 if (type == OP_PRTF || type == OP_SPRINTF) type = OP_ENTERSUB;
3935
11343788 3936 switch (o->op_type) {
68dc0745 3937 case OP_UNDEF:
3280af22 3938 PL_modcount++;
5dc0d613 3939 return o;
5f05dabc