callgrind/threads.c

   1 /*--------------------------------------------------------------------*/
   2 /*--- Callgrind                                                    ---*/
   3 /*---                                                 ct_threads.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
  31 #include "pub_tool_threadstate.h"
  32
  33 /* forward decls */
  34 static exec_state* exec_state_save(void);
  35 static exec_state* exec_state_restore(void);
  36 static exec_state* push_exec_state(int);
  37 static exec_state* top_exec_state(void);
  38
  39 static exec_stack current_states;
  40
  41
  42 /*------------------------------------------------------------*/
  43 /*--- Support for multi-threading                          ---*/
  44 /*------------------------------------------------------------*/
  45
  46
  47 /*
  48  * For Valgrind, MT is cooperative (no preemting in our code),
  49  * so we don't need locks...
  50  *
  51  * Per-thread data:
  52  *  - BBCCs
  53  *  - call stack
  54  *  - call hash
  55  *  - event counters: last, current
  56  *
  57  * Even when ignoring MT, we need this functions to set up some
  58  * datastructures for the process (= Thread 1).
  59  */
  60
  61 /* current running thread */
  62 ThreadId CLG_(current_tid);
  63
  64 static thread_info** thread;
  65
  66 thread_info** CLG_(get_threads)()
  67 {
  68   return thread;
  69 }
  70
  71 thread_info* CLG_(get_current_thread)()
  72 {
  73   return thread[CLG_(current_tid)];
  74 }
  75
  76 void CLG_(init_threads)()
  77 {
  78     UInt i;
  79
  80     thread = CLG_MALLOC("cl.threads.it.1", VG_N_THREADS * sizeof thread[0]);
  81
  82     for(i=0;i<VG_N_THREADS;i++)
  83         thread[i] = 0;
  84     CLG_(current_tid) = VG_INVALID_THREADID;
  85 }
  86
  87 /* switches through all threads and calls func */
  88 void CLG_(forall_threads)(void (*func)(thread_info*))
  89 {
  90   Int t, orig_tid = CLG_(current_tid);
  91
  92   for(t=1;t<VG_N_THREADS;t++) {
  93     if (!thread[t]) continue;
  94     CLG_(switch_thread)(t);
  95     (*func)(thread[t]);
  96   }
  97   CLG_(switch_thread)(orig_tid);
  98 }
  99
 100
 101 static
 102 thread_info* new_thread(void)
 103 {
 104     thread_info* t;
 105
 106     t = (thread_info*) CLG_MALLOC("cl.threads.nt.1",
 107                                   sizeof(thread_info));
 108
 109     /* init state */
 110     CLG_(init_exec_stack)( &(t->states) );
 111     CLG_(init_call_stack)( &(t->calls) );
 112     CLG_(init_fn_stack)  ( &(t->fns) );
 113     /* t->states.entry[0]->cxt = CLG_(get_cxt)(t->fns.bottom); */
 114
 115     /* event counters */
 116     t->lastdump_cost   = CLG_(get_eventset_cost)( CLG_(sets).full );
 117     t->sighandler_cost = CLG_(get_eventset_cost)( CLG_(sets).full );
 118     CLG_(init_cost)( CLG_(sets).full, t->lastdump_cost );
 119     CLG_(init_cost)( CLG_(sets).full, t->sighandler_cost );
 120
 121     /* init data containers */
 122     CLG_(init_fn_array)( &(t->fn_active) );
 123     CLG_(init_bbcc_hash)( &(t->bbccs) );
 124     CLG_(init_jcc_hash)( &(t->jccs) );
 125
 126     return t;
 127 }
 128
 129
 130 void CLG_(switch_thread)(ThreadId tid)
 131 {
 132   if (tid == CLG_(current_tid)) return;
 133
 134   CLG_DEBUG(0, ">> thread %u (was %u)\n", tid, CLG_(current_tid));
 135
 136   if (CLG_(current_tid) != VG_INVALID_THREADID) {
 137     /* save thread state */
 138     thread_info* t = thread[CLG_(current_tid)];
 139
 140     CLG_ASSERT(t != 0);
 141
 142     /* current context (including signal handler contexts) */
 143     exec_state_save();
 144     CLG_(copy_current_exec_stack)( &(t->states) );
 145     CLG_(copy_current_call_stack)( &(t->calls) );
 146     CLG_(copy_current_fn_stack)  ( &(t->fns) );
 147
 148     CLG_(copy_current_fn_array) ( &(t->fn_active) );
 149     /* If we cumulate costs of threads, use TID 1 for all jccs/bccs */
 150     if (!CLG_(clo).separate_threads) t = thread[1];
 151     CLG_(copy_current_bbcc_hash)( &(t->bbccs) );
 152     CLG_(copy_current_jcc_hash) ( &(t->jccs) );
 153   }
 154
 155   CLG_(current_tid) = tid;
 156   CLG_ASSERT(tid < VG_N_THREADS);
 157
 158   if (tid != VG_INVALID_THREADID) {
 159     thread_info* t;
 160
 161     /* load thread state */
 162
 163     if (thread[tid] == 0) thread[tid] = new_thread();
 164     t = thread[tid];
 165
 166     /* current context (including signal handler contexts) */
 167     CLG_(set_current_exec_stack)( &(t->states) );
 168     exec_state_restore();
 169     CLG_(set_current_call_stack)( &(t->calls) );
 170     CLG_(set_current_fn_stack)  ( &(t->fns) );
 171
 172     CLG_(set_current_fn_array)  ( &(t->fn_active) );
 173     /* If we cumulate costs of threads, use TID 1 for all jccs/bccs */
 174     if (!CLG_(clo).separate_threads) t = thread[1];
 175     CLG_(set_current_bbcc_hash) ( &(t->bbccs) );
 176     CLG_(set_current_jcc_hash)  ( &(t->jccs) );
 177   }
 178 }
 179
 180
 181 void CLG_(run_thread)(ThreadId tid)
 182 {
 183     /* check for dumps needed */
 184     static ULong bbs_done = 0;
 185     HChar buf[50];   // large enough
 186
 187     if (CLG_(clo).dump_every_bb >0) {
 188        if (CLG_(stat).bb_executions - bbs_done > CLG_(clo).dump_every_bb) {
 189            VG_(sprintf)(buf, "--dump-every-bb=%llu", CLG_(clo).dump_every_bb);
 190            CLG_(dump_profile)(buf, False);
 191            bbs_done = CLG_(stat).bb_executions;
 192        }
 193     }
 194
 195     /* now check for thread switch */
 196     CLG_(switch_thread)(tid);
 197 }
 198
 199 void CLG_(pre_signal)(ThreadId tid, Int sigNum, Bool alt_stack)
 200 {
 201     exec_state *es;
 202
 203     CLG_DEBUG(0, ">> pre_signal(TID %u, sig %d, alt_st %s)\n",
 204              tid, sigNum, alt_stack ? "yes":"no");
 205
 206     /* switch to the thread the handler runs in */
 207     CLG_(switch_thread)(tid);
 208
 209     /* save current execution state */
 210     exec_state_save();
 211
 212     /* setup new cxtinfo struct for this signal handler */
 213     es = push_exec_state(sigNum);
 214     CLG_(zero_cost)( CLG_(sets).full, es->cost );
 215     CLG_(current_state).cost = es->cost;
 216     es->call_stack_bottom = CLG_(current_call_stack).sp;
 217
 218     /* setup current state for a spontaneous call */
 219     CLG_(init_exec_state)( &CLG_(current_state) );
 220     CLG_(current_state).sig = sigNum;
 221     CLG_(push_cxt)(0);
 222 }
 223
 224 /* Run post-signal if the stackpointer for call stack is at
 225  * the bottom in current exec state (e.g. a signal handler)
 226  *
 227  * Called from CLG_(pop_call_stack)
 228  */
 229 void CLG_(run_post_signal_on_call_stack_bottom)()
 230 {
 231     exec_state* es = top_exec_state();
 232     CLG_ASSERT(es != 0);
 233     CLG_ASSERT(CLG_(current_state).sig >0);
 234
 235     if (CLG_(current_call_stack).sp == es->call_stack_bottom)
 236         CLG_(post_signal)( CLG_(current_tid), CLG_(current_state).sig );
 237 }
 238
 239 void CLG_(post_signal)(ThreadId tid, Int sigNum)
 240 {
 241     exec_state* es;
 242     UInt fn_number, *pactive;
 243
 244     CLG_DEBUG(0, ">> post_signal(TID %u, sig %d)\n",
 245              tid, sigNum);
 246
 247     /* thread switching potentially needed, eg. with instrumentation off */
 248     CLG_(switch_thread)(tid);
 249     CLG_ASSERT(sigNum == CLG_(current_state).sig);
 250
 251     /* Unwind call stack of this signal handler.
 252      * This should only be needed at finalisation time
 253      */
 254     es = top_exec_state();
 255     CLG_ASSERT(es != 0);
 256     while(CLG_(current_call_stack).sp > es->call_stack_bottom)
 257       CLG_(pop_call_stack)();
 258
 259     if (CLG_(current_state).cxt) {
 260       /* correct active counts */
 261       fn_number = CLG_(current_state).cxt->fn[0]->number;
 262       pactive = CLG_(get_fn_entry)(fn_number);
 263       (*pactive)--;
 264       CLG_DEBUG(0, "  set active count of %s back to %u\n",
 265                CLG_(current_state).cxt->fn[0]->name, *pactive);
 266     }
 267
 268     if (CLG_(current_fn_stack).top > CLG_(current_fn_stack).bottom) {
 269         /* set fn_stack_top back.
 270          * top can point to 0 if nothing was executed in the signal handler;
 271          * this is possible at end on unwinding handlers.
 272          */
 273         if (*(CLG_(current_fn_stack).top) != 0) {
 274             CLG_(current_fn_stack).top--;
 275             CLG_ASSERT(*(CLG_(current_fn_stack).top) == 0);
 276         }
 277       if (CLG_(current_fn_stack).top > CLG_(current_fn_stack).bottom)
 278         CLG_(current_fn_stack).top--;
 279     }
 280
 281     /* sum up costs */
 282     CLG_ASSERT(CLG_(current_state).cost == es->cost);
 283     CLG_(add_and_zero_cost)( CLG_(sets).full,
 284                             thread[CLG_(current_tid)]->sighandler_cost,
 285                             CLG_(current_state).cost );
 286
 287     /* restore previous context */
 288     es->sig = -1;
 289     current_states.sp--;
 290     es = top_exec_state();
 291     CLG_(current_state).sig = es->sig;
 292     exec_state_restore();
 293
 294     /* There is no way to reliable get the thread ID we are switching to
 295      * after this handler returns. So we sync with actual TID at start of
 296      * CLG_(setup_bb)(), which should be the next for callgrind.
 297      */
 298 }
 299
 300
 301
 302 /*------------------------------------------------------------*/
 303 /*--- Execution states in a thread & signal handlers       ---*/
 304 /*------------------------------------------------------------*/
 305
 306 /* Each thread can be interrupted by a signal handler, and they
 307  * themselves again. But as there's no scheduling among handlers
 308  * of the same thread, we don't need additional stacks.
 309  * So storing execution contexts and
 310  * adding separators in the callstack(needed to not intermix normal/handler
 311  * functions in contexts) should be enough.
 312  */
 313
 314 /* not initialized: call_stack_bottom, sig */
 315 void CLG_(init_exec_state)(exec_state* es)
 316 {
 317   es->collect = CLG_(clo).collect_atstart;
 318   es->cxt  = 0;
 319   es->jmps_passed = 0;
 320   es->bbcc = 0;
 321   es->nonskipped = 0;
 322 }
 323
 324
 325 static exec_state* new_exec_state(Int sigNum)
 326 {
 327     exec_state* es;
 328     es = (exec_state*) CLG_MALLOC("cl.threads.nes.1",
 329                                   sizeof(exec_state));
 330
 331     /* allocate real cost space: needed as incremented by
 332      * simulation functions */
 333     es->cost       = CLG_(get_eventset_cost)(CLG_(sets).full);
 334     CLG_(zero_cost)( CLG_(sets).full, es->cost );
 335     CLG_(init_exec_state)(es);
 336     es->sig        = sigNum;
 337     es->call_stack_bottom  = 0;
 338
 339     return es;
 340 }
 341
 342 void CLG_(init_exec_stack)(exec_stack* es)
 343 {
 344   Int i;
 345
 346   /* The first element is for the main thread */
 347   es->entry[0] = new_exec_state(0);
 348   for(i=1;i<MAX_SIGHANDLERS;i++)
 349     es->entry[i] = 0;
 350   es->sp = 0;
 351 }
 352
 353 void CLG_(copy_current_exec_stack)(exec_stack* dst)
 354 {
 355   Int i;
 356
 357   dst->sp = current_states.sp;
 358   for(i=0;i<MAX_SIGHANDLERS;i++)
 359     dst->entry[i] = current_states.entry[i];
 360 }
 361
 362 void CLG_(set_current_exec_stack)(exec_stack* dst)
 363 {
 364   Int i;
 365
 366   current_states.sp = dst->sp;
 367   for(i=0;i<MAX_SIGHANDLERS;i++)
 368     current_states.entry[i] = dst->entry[i];
 369 }
 370
 371
 372 /* Get top context info struct of current thread */
 373 static
 374 exec_state* top_exec_state(void)
 375 {
 376   Int sp = current_states.sp;
 377   exec_state* es;
 378
 379   CLG_ASSERT((sp >= 0) && (sp < MAX_SIGHANDLERS));
 380   es = current_states.entry[sp];
 381   CLG_ASSERT(es != 0);
 382   return es;
 383 }
 384
 385 /* Allocates a free context info structure for a new entered
 386  * signal handler, putting it on the context stack.
 387  * Returns a pointer to the structure.
 388  */
 389 static exec_state* push_exec_state(int sigNum)
 390 {
 391   Int sp;
 392   exec_state* es;
 393
 394   current_states.sp++;
 395   sp = current_states.sp;
 396
 397   CLG_ASSERT((sigNum > 0) && (sigNum <= _VKI_NSIG));
 398   CLG_ASSERT((sp > 0) && (sp < MAX_SIGHANDLERS));
 399   es = current_states.entry[sp];
 400   if (!es) {
 401     es = new_exec_state(sigNum);
 402     current_states.entry[sp] = es;
 403   }
 404   else
 405     es->sig = sigNum;
 406
 407   return es;
 408 }
 409
 410 /* Save current context to top cxtinfo struct */
 411 static
 412 exec_state* exec_state_save(void)
 413 {
 414   exec_state* es = top_exec_state();
 415
 416   es->cxt         = CLG_(current_state).cxt;
 417   es->collect     = CLG_(current_state).collect;
 418   es->jmps_passed = CLG_(current_state).jmps_passed;
 419   es->bbcc        = CLG_(current_state).bbcc;
 420   es->nonskipped  = CLG_(current_state).nonskipped;
 421   CLG_ASSERT(es->cost == CLG_(current_state).cost);
 422
 423   CLG_DEBUGIF(1) {
 424     CLG_DEBUG(1, "  cxtinfo_save(sig %d): collect %s, jmps_passed %d\n",
 425              es->sig, es->collect ? "Yes": "No", es->jmps_passed);
 426     CLG_(print_bbcc)(-9, es->bbcc);
 427     CLG_(print_cost)(-9, CLG_(sets).full, es->cost);
 428   }
 429
 430   /* signal number does not need to be saved */
 431   CLG_ASSERT(CLG_(current_state).sig == es->sig);
 432
 433   return es;
 434 }
 435
 436 static
 437 exec_state* exec_state_restore(void)
 438 {
 439   exec_state* es = top_exec_state();
 440
 441   CLG_(current_state).cxt     = es->cxt;
 442   CLG_(current_state).collect = es->collect;
 443   CLG_(current_state).jmps_passed = es->jmps_passed;
 444   CLG_(current_state).bbcc    = es->bbcc;
 445   CLG_(current_state).nonskipped = es->nonskipped;
 446   CLG_(current_state).cost    = es->cost;
 447   CLG_(current_state).sig     = es->sig;
 448
 449   CLG_DEBUGIF(1) {
 450         CLG_DEBUG(1, "  exec_state_restore(sig %d): collect %s, jmps_passed %d\n",
 451                   es->sig, es->collect ? "Yes": "No", es->jmps_passed);
 452         CLG_(print_bbcc)(-9, es->bbcc);
 453         CLG_(print_cxt)(-9, es->cxt, 0);
 454         CLG_(print_cost)(-9, CLG_(sets).full, es->cost);
 455   }
 456
 457   return es;
 458 }