1 /*--------------------------------------------------------------------*/
2 /*--- Callgrind ---*/
3 /*--- bbcc.c ---*/
4 /*--------------------------------------------------------------------*/
5
6 /*
7 This file is part of Callgrind, a Valgrind tool for call tracing.
8
9 Copyright (C) 2002-2017, Josef Weidendorfer (Josef.Weidendorfer@gmx.de)
10
11 This program is free software; you can redistribute it and/or
12 modify it under the terms of the GNU General Public License as
13 published by the Free Software Foundation; either version 2 of the
14 License, or (at your option) any later version.
15
16 This program is distributed in the hope that it will be useful, but
17 WITHOUT ANY WARRANTY; without even the implied warranty of
18 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 General Public License for more details.
20
21 You should have received a copy of the GNU General Public License
22 along with this program; if not, write to the Free Software
23 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
24 02111-1307, USA.
25
26 The GNU General Public License is contained in the file COPYING.
27 */
28
29 #include "global.h"
30 #include "costs.h"
31
32 #include "pub_tool_threadstate.h"
33
34 /*------------------------------------------------------------*/
35 /*--- BBCC operations ---*/
36 /*------------------------------------------------------------*/
37
38 #define N_BBCC_INITIAL_ENTRIES 10437
39
40 /* BBCC table (key is BB/Context), per thread, resizable */
41 bbcc_hash current_bbccs;
42
CLG_(init_bbcc_hash)43 void CLG_(init_bbcc_hash)(bbcc_hash* bbccs)
44 {
45 Int i;
46
47 CLG_ASSERT(bbccs != 0);
48
49 bbccs->size = N_BBCC_INITIAL_ENTRIES;
50 bbccs->entries = 0;
51 bbccs->table = (BBCC**) CLG_MALLOC("cl.bbcc.ibh.1",
52 bbccs->size * sizeof(BBCC*));
53
54 for (i = 0; i < bbccs->size; i++) bbccs->table[i] = NULL;
55 }
56
CLG_(copy_current_bbcc_hash)57 void CLG_(copy_current_bbcc_hash)(bbcc_hash* dst)
58 {
59 CLG_ASSERT(dst != 0);
60
61 dst->size = current_bbccs.size;
62 dst->entries = current_bbccs.entries;
63 dst->table = current_bbccs.table;
64 }
65
CLG_(get_current_bbcc_hash)66 bbcc_hash* CLG_(get_current_bbcc_hash)()
67 {
68 return ¤t_bbccs;
69 }
70
CLG_(set_current_bbcc_hash)71 void CLG_(set_current_bbcc_hash)(bbcc_hash* h)
72 {
73 CLG_ASSERT(h != 0);
74
75 current_bbccs.size = h->size;
76 current_bbccs.entries = h->entries;
77 current_bbccs.table = h->table;
78 }
79
80 /*
81 * Zero all costs of a BBCC
82 */
CLG_(zero_bbcc)83 void CLG_(zero_bbcc)(BBCC* bbcc)
84 {
85 Int i;
86 jCC* jcc;
87
88 CLG_ASSERT(bbcc->cxt != 0);
89 CLG_DEBUG(1, " zero_bbcc: BB %#lx, Cxt %u "
90 "(fn '%s', rec %u)\n",
91 bb_addr(bbcc->bb),
92 bbcc->cxt->base_number + bbcc->rec_index,
93 bbcc->cxt->fn[0]->name,
94 bbcc->rec_index);
95
96 if ((bbcc->ecounter_sum ==0) &&
97 (bbcc->ret_counter ==0)) return;
98
99 for(i=0;i<bbcc->bb->cost_count;i++)
100 bbcc->cost[i] = 0;
101 for(i=0;i <= bbcc->bb->cjmp_count;i++) {
102 bbcc->jmp[i].ecounter = 0;
103 for(jcc=bbcc->jmp[i].jcc_list; jcc; jcc=jcc->next_from)
104 CLG_(init_cost)( CLG_(sets).full, jcc->cost );
105 }
106 bbcc->ecounter_sum = 0;
107 bbcc->ret_counter = 0;
108 }
109
110
111
CLG_(forall_bbccs)112 void CLG_(forall_bbccs)(void (*func)(BBCC*))
113 {
114 BBCC *bbcc, *bbcc2;
115 int i, j;
116
117 for (i = 0; i < current_bbccs.size; i++) {
118 if ((bbcc=current_bbccs.table[i]) == NULL) continue;
119 while (bbcc) {
120 /* every bbcc should have a rec_array */
121 CLG_ASSERT(bbcc->rec_array != 0);
122
123 for(j=0;j<bbcc->cxt->fn[0]->separate_recursions;j++) {
124 if ((bbcc2 = bbcc->rec_array[j]) == 0) continue;
125
126 (*func)(bbcc2);
127 }
128 bbcc = bbcc->next;
129 }
130 }
131 }
132
133
134 /* All BBCCs for recursion level 0 are inserted into a
135 * thread specific hash table with key
136 * - address of BB structure (unique, as never freed)
137 * - current context (includes caller chain)
138 * BBCCs for other recursion levels are in bbcc->rec_array.
139 *
140 * The hash is used in setup_bb(), i.e. to find the cost
141 * counters to be changed in the execution of a BB.
142 */
143
144 static __inline__
bbcc_hash_idx(BB * bb,Context * cxt,UInt size)145 UInt bbcc_hash_idx(BB* bb, Context* cxt, UInt size)
146 {
147 CLG_ASSERT(bb != 0);
148 CLG_ASSERT(cxt != 0);
149
150 return ((Addr)bb + (Addr)cxt) % size;
151 }
152
153
154 /* Lookup for a BBCC in hash.
155 */
156 static
lookup_bbcc(BB * bb,Context * cxt)157 BBCC* lookup_bbcc(BB* bb, Context* cxt)
158 {
159 BBCC* bbcc = bb->last_bbcc;
160 UInt idx;
161
162 /* check LRU */
163 if (bbcc->cxt == cxt) {
164 if (!CLG_(clo).separate_threads) {
165 /* if we don't dump threads separate, tid doesn't have to match */
166 return bbcc;
167 }
168 if (bbcc->tid == CLG_(current_tid)) return bbcc;
169 }
170
171 CLG_(stat).bbcc_lru_misses++;
172
173 idx = bbcc_hash_idx(bb, cxt, current_bbccs.size);
174 bbcc = current_bbccs.table[idx];
175 while (bbcc &&
176 (bb != bbcc->bb ||
177 cxt != bbcc->cxt)) {
178 bbcc = bbcc->next;
179 }
180
181 CLG_DEBUG(2," lookup_bbcc(BB %#lx, Cxt %u, fn '%s'): %p (tid %u)\n",
182 bb_addr(bb), cxt->base_number, cxt->fn[0]->name,
183 bbcc, bbcc ? bbcc->tid : 0);
184
185 CLG_DEBUGIF(2)
186 if (bbcc) CLG_(print_bbcc)(-2,bbcc);
187
188 return bbcc;
189 }
190
191
192 /* double size of hash table 1 (addr->BBCC) */
resize_bbcc_hash(void)193 static void resize_bbcc_hash(void)
194 {
195 Int i, new_size, conflicts1 = 0, conflicts2 = 0;
196 BBCC** new_table;
197 UInt new_idx;
198 BBCC *curr_BBCC, *next_BBCC;
199
200 new_size = 2*current_bbccs.size+3;
201 new_table = (BBCC**) CLG_MALLOC("cl.bbcc.rbh.1",
202 new_size * sizeof(BBCC*));
203
204 for (i = 0; i < new_size; i++)
205 new_table[i] = NULL;
206
207 for (i = 0; i < current_bbccs.size; i++) {
208 if (current_bbccs.table[i] == NULL) continue;
209
210 curr_BBCC = current_bbccs.table[i];
211 while (NULL != curr_BBCC) {
212 next_BBCC = curr_BBCC->next;
213
214 new_idx = bbcc_hash_idx(curr_BBCC->bb,
215 curr_BBCC->cxt,
216 new_size);
217
218 curr_BBCC->next = new_table[new_idx];
219 new_table[new_idx] = curr_BBCC;
220 if (curr_BBCC->next) {
221 conflicts1++;
222 if (curr_BBCC->next->next)
223 conflicts2++;
224 }
225
226 curr_BBCC = next_BBCC;
227 }
228 }
229
230 VG_(free)(current_bbccs.table);
231
232
233 CLG_DEBUG(0,"Resize BBCC Hash: %u => %d (entries %u, conflicts %d/%d)\n",
234 current_bbccs.size, new_size,
235 current_bbccs.entries, conflicts1, conflicts2);
236
237 current_bbccs.size = new_size;
238 current_bbccs.table = new_table;
239 CLG_(stat).bbcc_hash_resizes++;
240 }
241
242
243 static __inline
new_recursion(int size)244 BBCC** new_recursion(int size)
245 {
246 BBCC** bbccs;
247 int i;
248
249 bbccs = (BBCC**) CLG_MALLOC("cl.bbcc.nr.1", sizeof(BBCC*) * size);
250 for(i=0;i<size;i++)
251 bbccs[i] = 0;
252
253 CLG_DEBUG(3," new_recursion(size %d): %p\n", size, bbccs);
254
255 return bbccs;
256 }
257
258
259 /*
260 * Allocate a new BBCC
261 *
262 * Uninitialized:
263 * cxt, rec_index, rec_array, next_bbcc, next1, next2
264 */
265 static __inline__
new_bbcc(BB * bb)266 BBCC* new_bbcc(BB* bb)
267 {
268 BBCC* bbcc;
269 Int i;
270
271 /* We need cjmp_count+1 JmpData structs:
272 * the last is for the unconditional jump/call/ret at end of BB
273 */
274 bbcc = (BBCC*)CLG_MALLOC("cl.bbcc.nb.1",
275 sizeof(BBCC) +
276 (bb->cjmp_count+1) * sizeof(JmpData));
277 bbcc->bb = bb;
278 bbcc->tid = CLG_(current_tid);
279
280 bbcc->ret_counter = 0;
281 bbcc->skipped = 0;
282 bbcc->cost = CLG_(get_costarray)(bb->cost_count);
283 for(i=0;i<bb->cost_count;i++)
284 bbcc->cost[i] = 0;
285 for(i=0; i<=bb->cjmp_count; i++) {
286 bbcc->jmp[i].ecounter = 0;
287 bbcc->jmp[i].jcc_list = 0;
288 }
289 bbcc->ecounter_sum = 0;
290
291 /* Init pointer caches (LRU) */
292 bbcc->lru_next_bbcc = 0;
293 bbcc->lru_from_jcc = 0;
294 bbcc->lru_to_jcc = 0;
295
296 CLG_(stat).distinct_bbccs++;
297
298 CLG_DEBUG(3, " new_bbcc(BB %#lx): %p (now %d)\n",
299 bb_addr(bb), bbcc, CLG_(stat).distinct_bbccs);
300
301 return bbcc;
302 }
303
304
305 /**
306 * Inserts a new BBCC into hashes.
307 * BBCC specific items must be set as this is used for the hash
308 * keys:
309 * fn : current function
310 * tid : current thread ID
311 * from : position where current function is called from
312 *
313 * Recursion level doesn't need to be set as this is not included
314 * in the hash key: Only BBCCs with rec level 0 are in hashes.
315 */
316 static
insert_bbcc_into_hash(BBCC * bbcc)317 void insert_bbcc_into_hash(BBCC* bbcc)
318 {
319 UInt idx;
320
321 CLG_ASSERT(bbcc->cxt != 0);
322
323 CLG_DEBUG(3,"+ insert_bbcc_into_hash(BB %#lx, fn '%s')\n",
324 bb_addr(bbcc->bb), bbcc->cxt->fn[0]->name);
325
326 /* check fill degree of hash and resize if needed (>90%) */
327 current_bbccs.entries++;
328 if (100 * current_bbccs.entries / current_bbccs.size > 90)
329 resize_bbcc_hash();
330
331 idx = bbcc_hash_idx(bbcc->bb, bbcc->cxt, current_bbccs.size);
332 bbcc->next = current_bbccs.table[idx];
333 current_bbccs.table[idx] = bbcc;
334
335 CLG_DEBUG(3,"- insert_bbcc_into_hash: %u entries\n",
336 current_bbccs.entries);
337 }
338
339 /* String is returned in a dynamically allocated buffer. Caller is
340 responsible for free'ing it. */
mangled_cxt(const Context * cxt,Int rec_index)341 static HChar* mangled_cxt(const Context* cxt, Int rec_index)
342 {
343 Int i, p;
344
345 if (!cxt) return VG_(strdup)("cl.bbcc.mcxt", "(no context)");
346
347 /* Overestimate the number of bytes we need to hold the string. */
348 SizeT need = 20; // rec_index + nul-terminator
349 for (i = 0; i < cxt->size; ++i)
350 need += VG_(strlen)(cxt->fn[i]->name) + 1; // 1 for leading '
351
352 HChar *mangled = CLG_MALLOC("cl.bbcc.mcxt", need);
353 p = VG_(sprintf)(mangled, "%s", cxt->fn[0]->name);
354 if (rec_index >0)
355 p += VG_(sprintf)(mangled+p, "'%d", rec_index +1);
356 for(i=1;i<cxt->size;i++)
357 p += VG_(sprintf)(mangled+p, "'%s", cxt->fn[i]->name);
358
359 return mangled;
360 }
361
362
363 /* Create a new BBCC as a copy of an existing one,
364 * but with costs set to 0 and jcc chains empty.
365 *
366 * This is needed when a BB is executed in another context than
367 * the one at instrumentation time of the BB.
368 *
369 * Use cases:
370 * rec_index == 0: clone from a BBCC with differing tid/cxt
371 * and insert into hashes
372 * rec_index >0 : clone from a BBCC with same tid/cxt and rec_index 0
373 * don't insert into hashes
374 */
clone_bbcc(BBCC * orig,Context * cxt,Int rec_index)375 static BBCC* clone_bbcc(BBCC* orig, Context* cxt, Int rec_index)
376 {
377 BBCC* bbcc;
378
379 CLG_DEBUG(3,"+ clone_bbcc(BB %#lx, rec %d, fn %s)\n",
380 bb_addr(orig->bb), rec_index, cxt->fn[0]->name);
381
382 bbcc = new_bbcc(orig->bb);
383
384 if (rec_index == 0) {
385
386 /* hash insertion is only allowed if tid or cxt is different */
387 CLG_ASSERT((orig->tid != CLG_(current_tid)) ||
388 (orig->cxt != cxt));
389
390 bbcc->rec_index = 0;
391 bbcc->cxt = cxt;
392 bbcc->rec_array = new_recursion(cxt->fn[0]->separate_recursions);
393 bbcc->rec_array[0] = bbcc;
394
395 insert_bbcc_into_hash(bbcc);
396 }
397 else {
398 if (CLG_(clo).separate_threads)
399 CLG_ASSERT(orig->tid == CLG_(current_tid));
400
401 CLG_ASSERT(orig->cxt == cxt);
402 CLG_ASSERT(orig->rec_array);
403 CLG_ASSERT(cxt->fn[0]->separate_recursions > rec_index);
404 CLG_ASSERT(orig->rec_array[rec_index] ==0);
405
406 /* new BBCC will only have differing recursion level */
407 bbcc->rec_index = rec_index;
408 bbcc->cxt = cxt;
409 bbcc->rec_array = orig->rec_array;
410 bbcc->rec_array[rec_index] = bbcc;
411 }
412
413 /* update list of BBCCs for same BB */
414 bbcc->next_bbcc = orig->bb->bbcc_list;
415 orig->bb->bbcc_list = bbcc;
416
417
418 CLG_DEBUGIF(3)
419 CLG_(print_bbcc)(-2, bbcc);
420
421 HChar *mangled_orig = mangled_cxt(orig->cxt, orig->rec_index);
422 HChar *mangled_bbcc = mangled_cxt(bbcc->cxt, bbcc->rec_index);
423 CLG_DEBUG(2,"- clone_BBCC(%p, %d) for BB %#lx\n"
424 " orig %s\n"
425 " new %s\n",
426 orig, rec_index, bb_addr(orig->bb),
427 mangled_orig,
428 mangled_bbcc);
429 CLG_FREE(mangled_orig);
430 CLG_FREE(mangled_bbcc);
431
432 CLG_(stat).bbcc_clones++;
433
434 return bbcc;
435 };
436
437
438
439 /* Get a pointer to the cost centre structure for given basic block
440 * address. If created, the BBCC is inserted into the BBCC hash.
441 * Also sets BB_seen_before by reference.
442 *
443 */
CLG_(get_bbcc)444 BBCC* CLG_(get_bbcc)(BB* bb)
445 {
446 BBCC* bbcc;
447
448 CLG_DEBUG(3, "+ get_bbcc(BB %#lx)\n", bb_addr(bb));
449
450 bbcc = bb->bbcc_list;
451
452 if (!bbcc) {
453 bbcc = new_bbcc(bb);
454
455 /* initialize BBCC */
456 bbcc->cxt = 0;
457 bbcc->rec_array = 0;
458 bbcc->rec_index = 0;
459
460 bbcc->next_bbcc = bb->bbcc_list;
461 bb->bbcc_list = bbcc;
462 bb->last_bbcc = bbcc;
463
464 CLG_DEBUGIF(3)
465 CLG_(print_bbcc)(-2, bbcc);
466 }
467
468 CLG_DEBUG(3, "- get_bbcc(BB %#lx): BBCC %p\n",
469 bb_addr(bb), bbcc);
470
471 return bbcc;
472 }
473
474
475 /* Callgrind manages its own call stack for each thread.
476 * When leaving a function, a underflow can happen when
477 * Callgrind's tracing was switched on in the middle of
478 * a run, i.e. when Callgrind was not able to trace the
479 * call instruction.
480 * This function tries to reconstruct the original call.
481 * As we know the return address (the address following
482 * the CALL instruction), we can detect the function
483 * we return back to, but the original call site is unknown.
484 * We suppose a call site at return address - 1.
485 * (TODO: other heuristic: lookup info of instrumented BBs).
486 */
handleUnderflow(BB * bb)487 static void handleUnderflow(BB* bb)
488 {
489 /* RET at top of call stack */
490 BBCC* source_bbcc;
491 BB* source_bb;
492 Bool seen_before;
493 fn_node* caller;
494 int fn_number;
495 unsigned *pactive;
496 call_entry* call_entry_up;
497
498 CLG_DEBUG(1," Callstack underflow !\n");
499
500 /* we emulate an old call from the function we return to
501 * by using (<return address> -1) */
502 source_bb = CLG_(get_bb)(bb_addr(bb)-1, 0, &seen_before);
503 source_bbcc = CLG_(get_bbcc)(source_bb);
504
505 /* seen_before can be true if RET from a signal handler */
506 if (!seen_before) {
507 source_bbcc->ecounter_sum = CLG_(current_state).collect ? 1 : 0;
508 }
509 else if (CLG_(current_state).collect)
510 source_bbcc->ecounter_sum++;
511
512 /* Force a new top context, will be set active by push_cxt() */
513 CLG_(current_fn_stack).top--;
514 CLG_(current_state).cxt = 0;
515 caller = CLG_(get_fn_node)(bb);
516 CLG_(push_cxt)( caller );
517
518 if (!seen_before) {
519 /* set rec array for source BBCC: this is at rec level 1 */
520 source_bbcc->rec_array = new_recursion(caller->separate_recursions);
521 source_bbcc->rec_array[0] = source_bbcc;
522
523 CLG_ASSERT(source_bbcc->cxt == 0);
524 source_bbcc->cxt = CLG_(current_state).cxt;
525 insert_bbcc_into_hash(source_bbcc);
526 }
527 CLG_ASSERT(CLG_(current_state).bbcc);
528
529 /* correct active counts */
530 fn_number = CLG_(current_state).bbcc->cxt->fn[0]->number;
531 pactive = CLG_(get_fn_entry)(fn_number);
532 (*pactive)--;
533
534 /* This assertion is not correct for reentrant
535 * signal handlers */
536 /* CLG_ASSERT(*pactive == 0); */
537
538 CLG_(current_state).nonskipped = 0; /* we didn't skip this function */
539 /* back to current context */
540 CLG_(push_cxt)( CLG_(current_state).bbcc->cxt->fn[0] );
541 CLG_(push_call_stack)(source_bbcc, 0, CLG_(current_state).bbcc,
542 (Addr)-1, False);
543 call_entry_up =
544 &(CLG_(current_call_stack).entry[CLG_(current_call_stack).sp -1]);
545 /* assume this call is lasting since last dump or
546 * for a signal handler since it's call */
547 if (CLG_(current_state).sig == 0)
548 CLG_(copy_cost)( CLG_(sets).full, call_entry_up->enter_cost,
549 CLG_(get_current_thread)()->lastdump_cost );
550 else
551 CLG_(zero_cost)( CLG_(sets).full, call_entry_up->enter_cost );
552 }
553
554
555 /*
556 * Helper function called at start of each instrumented BB to setup
557 * pointer to costs for current thread/context/recursion level
558 */
559
560 VG_REGPARM(1)
CLG_(setup_bbcc)561 void CLG_(setup_bbcc)(BB* bb)
562 {
563 BBCC *bbcc, *last_bbcc;
564 Bool call_emulation = False, delayed_push = False, skip = False;
565 Addr sp;
566 BB* last_bb;
567 ThreadId tid;
568 ClgJumpKind jmpkind;
569 Bool isConditionalJump;
570 Int passed = 0, csp;
571 Bool ret_without_call = False;
572 Int popcount_on_return = 1;
573
574 CLG_DEBUG(3,"+ setup_bbcc(BB %#lx)\n", bb_addr(bb));
575
576 /* This is needed because thread switches can not reliable be tracked
577 * with callback CLG_(run_thread) only: we have otherwise no way to get
578 * the thread ID after a signal handler returns.
579 * This could be removed again if that bug is fixed in Valgrind.
580 * This is in the hot path but hopefully not to costly.
581 */
582 tid = VG_(get_running_tid)();
583 #if 1
584 /* CLG_(switch_thread) is a no-op when tid is equal to CLG_(current_tid).
585 * As this is on the hot path, we only call CLG_(switch_thread)(tid)
586 * if tid differs from the CLG_(current_tid).
587 */
588 if (UNLIKELY(tid != CLG_(current_tid)))
589 CLG_(switch_thread)(tid);
590 #else
591 CLG_ASSERT(VG_(get_running_tid)() == CLG_(current_tid));
592 #endif
593
594 sp = VG_(get_SP)(tid);
595 last_bbcc = CLG_(current_state).bbcc;
596 last_bb = last_bbcc ? last_bbcc->bb : 0;
597
598 if (last_bb) {
599 passed = CLG_(current_state).jmps_passed;
600 CLG_ASSERT(passed <= last_bb->cjmp_count);
601 jmpkind = last_bb->jmp[passed].jmpkind;
602 isConditionalJump = (passed < last_bb->cjmp_count);
603
604 if (CLG_(current_state).collect) {
605 if (!CLG_(current_state).nonskipped) {
606 last_bbcc->ecounter_sum++;
607 last_bbcc->jmp[passed].ecounter++;
608 if (!CLG_(clo).simulate_cache) {
609 /* update Ir cost */
610 UInt instr_count = last_bb->jmp[passed].instr+1;
611 CLG_(current_state).cost[ fullOffset(EG_IR) ] += instr_count;
612 }
613 }
614 else {
615 /* do not increment exe counter of BBs in skipped functions, as it
616 * would fool dumping code */
617 if (!CLG_(clo).simulate_cache) {
618 /* update Ir cost */
619 UInt instr_count = last_bb->jmp[passed].instr+1;
620 CLG_(current_state).cost[ fullOffset(EG_IR) ] += instr_count;
621 CLG_(current_state).nonskipped->skipped[ fullOffset(EG_IR) ]
622 += instr_count;
623 }
624 }
625 }
626
627 CLG_DEBUGIF(4) {
628 CLG_(print_execstate)(-2, &CLG_(current_state) );
629 CLG_(print_bbcc_cost)(-2, last_bbcc);
630 }
631 }
632 else {
633 jmpkind = jk_None;
634 isConditionalJump = False;
635 }
636
637 /* Manipulate JmpKind if needed, only using BB specific info */
638
639 csp = CLG_(current_call_stack).sp;
640
641 /* A return not matching the top call in our callstack is a jump */
642 if ( (jmpkind == jk_Return) && (csp >0)) {
643 Int csp_up = csp-1;
644 call_entry* top_ce = &(CLG_(current_call_stack).entry[csp_up]);
645
646 /* We have a real return if
647 * - the stack pointer (SP) left the current stack frame, or
648 * - SP has the same value as when reaching the current function
649 * and the address of this BB is the return address of last call
650 * (we even allow to leave multiple frames if the SP stays the
651 * same and we find a matching return address)
652 * The latter condition is needed because on PPC, SP can stay
653 * the same over CALL=b(c)l / RET=b(c)lr boundaries
654 */
655 if (sp < top_ce->sp) popcount_on_return = 0;
656 else if (top_ce->sp == sp) {
657 while(1) {
658 if (top_ce->ret_addr == bb_addr(bb)) break;
659 if (csp_up>0) {
660 csp_up--;
661 top_ce = &(CLG_(current_call_stack).entry[csp_up]);
662 if (top_ce->sp == sp) {
663 popcount_on_return++;
664 continue;
665 }
666 }
667 popcount_on_return = 0;
668 break;
669 }
670 }
671 if (popcount_on_return == 0) {
672 jmpkind = jk_Jump;
673 ret_without_call = True;
674 }
675 }
676
677 /* Should this jump be converted to call or pop/call ? */
678 if (( jmpkind != jk_Return) &&
679 ( jmpkind != jk_Call) && last_bb) {
680
681 /* We simulate a JMP/Cont to be a CALL if
682 * - jump is in another ELF object or section kind
683 * - jump is to first instruction of a function (tail recursion)
684 */
685 if (ret_without_call ||
686 /* This is for detection of optimized tail recursion.
687 * On PPC, this is only detected as call when going to another
688 * function. The problem is that on PPC it can go wrong
689 * more easily (no stack frame setup needed)
690 */
691 #if defined(VGA_ppc32)
692 (bb->is_entry && (last_bb->fn != bb->fn)) ||
693 #else
694 bb->is_entry ||
695 #endif
696 (last_bb->sect_kind != bb->sect_kind) ||
697 (last_bb->obj->number != bb->obj->number)) {
698
699 CLG_DEBUG(1," JMP: %s[%s] to %s[%s]%s!\n",
700 last_bb->fn->name, last_bb->obj->name,
701 bb->fn->name, bb->obj->name,
702 ret_without_call?" (RET w/o CALL)":"");
703
704 if (CLG_(get_fn_node)(last_bb)->pop_on_jump && (csp>0)) {
705
706 call_entry* top_ce = &(CLG_(current_call_stack).entry[csp-1]);
707
708 if (top_ce->jcc) {
709
710 CLG_DEBUG(1," Pop on Jump!\n");
711
712 /* change source for delayed push */
713 CLG_(current_state).bbcc = top_ce->jcc->from;
714 sp = top_ce->sp;
715 passed = top_ce->jcc->jmp;
716 CLG_(pop_call_stack)();
717 }
718 else {
719 CLG_ASSERT(CLG_(current_state).nonskipped != 0);
720 }
721 }
722
723 jmpkind = jk_Call;
724 call_emulation = True;
725 }
726 }
727
728 if (jmpkind == jk_Call)
729 skip = CLG_(get_fn_node)(bb)->skip;
730
731 CLG_DEBUGIF(1) {
732 if (isConditionalJump)
733 VG_(printf)("Cond-");
734 switch(jmpkind) {
735 case jk_None: VG_(printf)("Fall-through"); break;
736 case jk_Jump: VG_(printf)("Jump"); break;
737 case jk_Call: VG_(printf)("Call"); break;
738 case jk_Return: VG_(printf)("Return"); break;
739 default: tl_assert(0);
740 }
741 VG_(printf)(" %08lx -> %08lx, SP %08lx\n",
742 last_bb ? bb_jmpaddr(last_bb) : 0,
743 bb_addr(bb), sp);
744 }
745
746 /* Handle CALL/RET and update context to get correct BBCC */
747
748 if (jmpkind == jk_Return) {
749
750 if ((csp == 0) ||
751 ((CLG_(current_fn_stack).top > CLG_(current_fn_stack).bottom) &&
752 ( *(CLG_(current_fn_stack).top-1)==0)) ) {
753
754 /* On an empty call stack or at a signal separation marker,
755 * a RETURN generates an call stack underflow.
756 */
757 handleUnderflow(bb);
758 CLG_(pop_call_stack)();
759 }
760 else {
761 CLG_ASSERT(popcount_on_return >0);
762 CLG_(unwind_call_stack)(sp, popcount_on_return);
763 }
764 }
765 else {
766 Int unwind_count = CLG_(unwind_call_stack)(sp, 0);
767 if (unwind_count > 0) {
768 /* if unwinding was done, this actually is a return */
769 jmpkind = jk_Return;
770 }
771
772 if (jmpkind == jk_Call) {
773 delayed_push = True;
774
775 csp = CLG_(current_call_stack).sp;
776 if (call_emulation && csp>0)
777 sp = CLG_(current_call_stack).entry[csp-1].sp;
778
779 }
780 }
781
782 /* Change new context if needed, taking delayed_push into account */
783 if ((delayed_push && !skip) || (CLG_(current_state).cxt == 0)) {
784 CLG_(push_cxt)(CLG_(get_fn_node)(bb));
785 }
786 CLG_ASSERT(CLG_(current_fn_stack).top > CLG_(current_fn_stack).bottom);
787
788 /* If there is a fresh instrumented BBCC, assign current context */
789 bbcc = CLG_(get_bbcc)(bb);
790 if (bbcc->cxt == 0) {
791 CLG_ASSERT(bbcc->rec_array == 0);
792
793 bbcc->cxt = CLG_(current_state).cxt;
794 bbcc->rec_array =
795 new_recursion((*CLG_(current_fn_stack).top)->separate_recursions);
796 bbcc->rec_array[0] = bbcc;
797
798 insert_bbcc_into_hash(bbcc);
799 }
800 else {
801 /* get BBCC with current context */
802
803 /* first check LRU of last bbcc executed */
804
805 if (last_bbcc) {
806 bbcc = last_bbcc->lru_next_bbcc;
807 if (bbcc &&
808 ((bbcc->bb != bb) ||
809 (bbcc->cxt != CLG_(current_state).cxt)))
810 bbcc = 0;
811 }
812 else
813 bbcc = 0;
814
815 if (!bbcc)
816 bbcc = lookup_bbcc(bb, CLG_(current_state).cxt);
817 if (!bbcc)
818 bbcc = clone_bbcc(bb->bbcc_list, CLG_(current_state).cxt, 0);
819
820 bb->last_bbcc = bbcc;
821 }
822
823 /* save for fast lookup */
824 if (last_bbcc)
825 last_bbcc->lru_next_bbcc = bbcc;
826
827 if ((*CLG_(current_fn_stack).top)->separate_recursions >1) {
828 UInt level, idx;
829 fn_node* top = *(CLG_(current_fn_stack).top);
830
831 level = *CLG_(get_fn_entry)(top->number);
832
833 if (delayed_push && !skip) {
834 if (CLG_(clo).skip_direct_recursion) {
835 /* a call was detected, which means that the source BB != 0 */
836 CLG_ASSERT(CLG_(current_state).bbcc != 0);
837 /* only increment rec. level if called from different function */
838 if (CLG_(current_state).bbcc->cxt->fn[0] != bbcc->cxt->fn[0])
839 level++;
840 }
841 else level++;
842 }
843 if (level> top->separate_recursions)
844 level = top->separate_recursions;
845
846 if (level == 0) {
847 /* can only happen if instrumentation just was switched on */
848 level = 1;
849 *CLG_(get_fn_entry)(top->number) = 1;
850 }
851
852 idx = level -1;
853 if (bbcc->rec_array[idx])
854 bbcc = bbcc->rec_array[idx];
855 else
856 bbcc = clone_bbcc(bbcc, CLG_(current_state).cxt, idx);
857
858 CLG_ASSERT(bbcc->rec_array[bbcc->rec_index] == bbcc);
859 }
860
861 if (delayed_push) {
862 if (!skip && CLG_(current_state).nonskipped) {
863 /* a call from skipped to nonskipped */
864 CLG_(current_state).bbcc = CLG_(current_state).nonskipped;
865 /* FIXME: take the real passed count from shadow stack */
866 passed = CLG_(current_state).bbcc->bb->cjmp_count;
867 }
868 CLG_(push_call_stack)(CLG_(current_state).bbcc, passed,
869 bbcc, sp, skip);
870 }
871
872 if (CLG_(clo).collect_jumps && (jmpkind == jk_Jump)) {
873
874 /* Handle conditional jumps followed, i.e. trace arcs
875 * This uses JCC structures, too */
876
877 jCC* jcc = CLG_(get_jcc)(last_bbcc, passed, bbcc);
878 CLG_ASSERT(jcc != 0);
879 // Change from default, and check if already changed
880 if (jcc->jmpkind == jk_Call)
881 jcc->jmpkind = isConditionalJump ? jk_CondJump : jk_Jump;
882 else {
883 // FIXME: Why can this fail?
884 // CLG_ASSERT(jcc->jmpkind == jmpkind);
885 }
886
887 jcc->call_counter++;
888 if (isConditionalJump)
889 CLG_(stat).jcnd_counter++;
890 else
891 CLG_(stat).jump_counter++;
892 }
893
894 CLG_(current_state).bbcc = bbcc;
895 /* Even though this will be set in instrumented code directly before
896 * side exits, it needs to be set to 0 here in case an exception
897 * happens in first instructions of the BB */
898 CLG_(current_state).jmps_passed = 0;
899 // needed for log_* handlers called in this BB
900 CLG_(bb_base) = bb->obj->offset + bb->offset;
901 CLG_(cost_base) = bbcc->cost;
902
903 CLG_DEBUGIF(1) {
904 VG_(printf)(" ");
905 CLG_(print_bbcc_fn)(bbcc);
906 VG_(printf)("\n");
907 }
908
909 CLG_DEBUG(3,"- setup_bbcc (BB %#lx): Cost %p (Len %u), Instrs %u (Len %u)\n",
910 bb_addr(bb), bbcc->cost, bb->cost_count,
911 bb->instr_count, bb->instr_len);
912 CLG_DEBUGIF(3)
913 CLG_(print_cxt)(-8, CLG_(current_state).cxt, bbcc->rec_index);
914 CLG_DEBUG(3,"\n");
915
916 CLG_(stat).bb_executions++;
917 }
918