callgrind/callstack.c

   1 /*--------------------------------------------------------------------*/
   2 /*--- Callgrind                                                    ---*/
   3 /*---                                               ct_callstack.c ---*/
   4 /*--------------------------------------------------------------------*/
   5
   6 /*
   7    This file is part of Callgrind, a Valgrind tool for call tracing.
   8
   9    Copyright (C) 2002-2011, 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 /*------------------------------------------------------------*/
  32 /*--- Call stack, operations                               ---*/
  33 /*------------------------------------------------------------*/
  34
  35 /* Stack of current thread. Gets initialized when switching to 1st thread.
  36  *
  37  * The artificial call stack is an array of call_entry's, representing
  38  * stack frames of the executing program.
  39  * Array call_stack and call_stack_esp have same size and grow on demand.
  40  * Array call_stack_esp holds SPs of corresponding stack frames.
  41  *
  42  */
  43
  44 #define N_CALL_STACK_INITIAL_ENTRIES 500
  45
  46 call_stack CLG_(current_call_stack);
  47
  48 void CLG_(init_call_stack)(call_stack* s)
  49 {
  50   Int i;
  51
  52   CLG_ASSERT(s != 0);
  53
  54   s->size = N_CALL_STACK_INITIAL_ENTRIES;
  55   s->entry = (call_entry*) CLG_MALLOC("cl.callstack.ics.1",
  56                                       s->size * sizeof(call_entry));
  57   s->sp = 0;
  58   s->entry[0].cxt = 0; /* for assertion in push_cxt() */
  59
  60   for(i=0; i<s->size; i++) s->entry[i].enter_cost = 0;
  61 }
  62
  63 call_entry* CLG_(get_call_entry)(Int sp)
  64 {
  65   CLG_ASSERT(sp <= CLG_(current_call_stack).sp);
  66   return &(CLG_(current_call_stack).entry[sp]);
  67 }
  68
  69 void CLG_(copy_current_call_stack)(call_stack* dst)
  70 {
  71   CLG_ASSERT(dst != 0);
  72
  73   dst->size  = CLG_(current_call_stack).size;
  74   dst->entry = CLG_(current_call_stack).entry;
  75   dst->sp    = CLG_(current_call_stack).sp;
  76 }
  77
  78 void CLG_(set_current_call_stack)(call_stack* s)
  79 {
  80   CLG_ASSERT(s != 0);
  81
  82   CLG_(current_call_stack).size  = s->size;
  83   CLG_(current_call_stack).entry = s->entry;
  84   CLG_(current_call_stack).sp    = s->sp;
  85 }
  86
  87
  88 static __inline__
  89 void ensure_stack_size(Int i)
  90 {
  91   Int oldsize;
  92   call_stack *cs = &CLG_(current_call_stack);
  93
  94   if (i < cs->size) return;
  95
  96   oldsize = cs->size;
  97   cs->size *= 2;
  98   while (i > cs->size) cs->size *= 2;
  99
 100   cs->entry = (call_entry*) VG_(realloc)("cl.callstack.ess.1",
 101                                          cs->entry,
 102                                          cs->size * sizeof(call_entry));
 103
 104   for(i=oldsize; i<cs->size; i++)
 105     cs->entry[i].enter_cost = 0;
 106
 107   CLG_(stat).call_stack_resizes++;
 108
 109   CLG_DEBUGIF(2)
 110     VG_(printf)("        call stack enlarged to %d entries\n",
 111                 CLG_(current_call_stack).size);
 112 }
 113
 114
 115
 116 /* Called when function entered nonrecursive */
 117 static void function_entered(fn_node* fn)
 118 {
 119   CLG_ASSERT(fn != 0);
 120
 121 #if CLG_ENABLE_DEBUG
 122   if (fn->verbosity >=0) {
 123     Int old = CLG_(clo).verbose;
 124     CLG_(clo).verbose = fn->verbosity;
 125     fn->verbosity = old;
 126     VG_(message)(Vg_DebugMsg,
 127                  "Entering %s: Verbosity set to %d\n",
 128                  fn->name, CLG_(clo).verbose);
 129   }
 130 #endif
 131
 132   if (fn->dump_before) {
 133     Char trigger[FN_NAME_LEN];
 134     VG_(sprintf)(trigger, "--dump-before=%s", fn->name);
 135     CLG_(dump_profile)(trigger, True);
 136   }
 137   else if (fn->zero_before) {
 138     CLG_(zero_all_cost)(True);
 139   }
 140
 141   if (fn->toggle_collect) {
 142     CLG_(current_state).collect = !CLG_(current_state).collect;
 143     CLG_DEBUG(2,"   entering %s: toggled collection state to %s\n",
 144              fn->name,
 145              CLG_(current_state).collect ? "ON" : "OFF");
 146   }
 147 }
 148
 149 /* Called when function left (no recursive level active) */
 150 static void function_left(fn_node* fn)
 151 {
 152   CLG_ASSERT(fn != 0);
 153
 154   if (fn->dump_after) {
 155     Char trigger[FN_NAME_LEN];
 156     VG_(sprintf)(trigger, "--dump-after=%s", fn->name);
 157     CLG_(dump_profile)(trigger, True);
 158   }
 159   if (fn->toggle_collect) {
 160     CLG_(current_state).collect = !CLG_(current_state).collect;
 161     CLG_DEBUG(2,"   leaving %s: toggled collection state to %s\n",
 162              fn->name,
 163              CLG_(current_state).collect ? "ON" : "OFF");
 164   }
 165
 166 #if CLG_ENABLE_DEBUG
 167   if (fn->verbosity >=0) {
 168     Int old = CLG_(clo).verbose;
 169     CLG_(clo).verbose = fn->verbosity;
 170     fn->verbosity = old;
 171     VG_(message)(Vg_DebugMsg,
 172                  "Leaving %s: Verbosity set back to %d\n",
 173                  fn->name, CLG_(clo).verbose);
 174   }
 175 #endif
 176 }
 177
 178
 179 /* Push call on call stack.
 180  *
 181  * Increment the usage count for the function called.
 182  * A jump from <from> to <to>, with <sp>.
 183  * If <skip> is true, this is a call to a function to be skipped;
 184  * for this, we set jcc = 0.
 185  */
 186 void CLG_(push_call_stack)(BBCC* from, UInt jmp, BBCC* to, Addr sp, Bool skip)
 187 {
 188     jCC* jcc;
 189     UInt* pdepth;
 190     call_entry* current_entry;
 191     Addr ret_addr;
 192
 193     /* Ensure a call stack of size <current_sp>+1.
 194      * The +1 is needed as push_cxt will store the
 195      * context at [current_sp]
 196      */
 197     ensure_stack_size(CLG_(current_call_stack).sp +1);
 198     current_entry = &(CLG_(current_call_stack).entry[CLG_(current_call_stack).sp]);
 199
 200     if (skip) {
 201         jcc = 0;
 202     }
 203     else {
 204         fn_node* to_fn = to->cxt->fn[0];
 205
 206         if (CLG_(current_state).nonskipped) {
 207             /* this is a jmp from skipped to nonskipped */
 208             CLG_ASSERT(CLG_(current_state).nonskipped == from);
 209         }
 210
 211         /* As push_cxt() has to be called before push_call_stack if not
 212          * skipping, the old context should already be saved on the stack */
 213         CLG_ASSERT(current_entry->cxt != 0);
 214         CLG_(copy_cost_lz)( CLG_(sets).full, &(current_entry->enter_cost),
 215                            CLG_(current_state).cost );
 216
 217         jcc = CLG_(get_jcc)(from, jmp, to);
 218         CLG_ASSERT(jcc != 0);
 219
 220         pdepth = CLG_(get_fn_entry)(to_fn->number);
 221         if (CLG_(clo).skip_direct_recursion) {
 222             /* only increment depth if another function is called */
 223           if (jcc->from->cxt->fn[0] != to_fn) (*pdepth)++;
 224         }
 225         else (*pdepth)++;
 226
 227         if (*pdepth>1)
 228           CLG_(stat).rec_call_counter++;
 229
 230         jcc->call_counter++;
 231         CLG_(stat).call_counter++;
 232
 233         if (*pdepth == 1) function_entered(to_fn);
 234     }
 235
 236     /* return address is only is useful with a real call;
 237      * used to detect RET w/o CALL */
 238     if (from->bb->jmp[jmp].jmpkind == jk_Call) {
 239       UInt instr = from->bb->jmp[jmp].instr;
 240       ret_addr = bb_addr(from->bb) +
 241         from->bb->instr[instr].instr_offset +
 242         from->bb->instr[instr].instr_size;
 243     }
 244     else
 245       ret_addr = 0;
 246
 247     /* put jcc on call stack */
 248     current_entry->jcc = jcc;
 249     current_entry->sp = sp;
 250     current_entry->ret_addr = ret_addr;
 251     current_entry->nonskipped = CLG_(current_state).nonskipped;
 252
 253     CLG_(current_call_stack).sp++;
 254
 255     /* To allow for above assertion we set context of next frame to 0 */
 256     CLG_ASSERT(CLG_(current_call_stack).sp < CLG_(current_call_stack).size);
 257     current_entry++;
 258     current_entry->cxt = 0;
 259
 260     if (!skip)
 261         CLG_(current_state).nonskipped = 0;
 262     else if (!CLG_(current_state).nonskipped) {
 263         /* a call from nonskipped to skipped */
 264         CLG_(current_state).nonskipped = from;
 265         if (!CLG_(current_state).nonskipped->skipped) {
 266           CLG_(init_cost_lz)( CLG_(sets).full,
 267                              &CLG_(current_state).nonskipped->skipped);
 268           CLG_(stat).distinct_skips++;
 269         }
 270     }
 271
 272 #if CLG_ENABLE_DEBUG
 273     CLG_DEBUGIF(0) {
 274         if (CLG_(clo).verbose<2) {
 275           if (jcc && jcc->to && jcc->to->bb) {
 276             char spaces[][41] = { "   .   .   .   .   .   .   .   .   .   .",
 277                                   "  .   .   .   .   .   .   .   .   .   . ",
 278                                   " .   .   .   .   .   .   .   .   .   .  ",
 279                                   ".   .   .   .   .   .   .   .   .   .   " };
 280
 281             int s = CLG_(current_call_stack).sp;
 282             Int* pars = (Int*) sp;
 283
 284             BB* bb = jcc->to->bb;
 285             if (s>40) s=40;
 286             VG_(printf)("%s> %s(0x%x, 0x%x, ...) [%s / %#lx]\n", spaces[s%4]+40-s, bb->fn->name,
 287                         pars ? pars[1]:0,
 288                         pars ? pars[2]:0,
 289                         bb->obj->name + bb->obj->last_slash_pos,
 290                         bb->offset);
 291           }
 292         }
 293         else if (CLG_(clo).verbose<4) {
 294             VG_(printf)("+ %2d ", CLG_(current_call_stack).sp);
 295             CLG_(print_short_jcc)(jcc);
 296             VG_(printf)(", SP %#lx, RA %#lx\n", sp, ret_addr);
 297         }
 298         else {
 299             VG_(printf)("  Pushed ");
 300             CLG_(print_stackentry)(3, CLG_(current_call_stack).sp-1);
 301         }
 302     }
 303 #endif
 304
 305 }
 306
 307
 308 /* Pop call stack and update inclusive sums.
 309  * Returns modified fcc.
 310  *
 311  * If the JCC becomes inactive, call entries are freed if possible
 312  */
 313 void CLG_(pop_call_stack)()
 314 {
 315     jCC* jcc;
 316     Int depth = 0;
 317     call_entry* lower_entry;
 318
 319     if (CLG_(current_state).sig >0) {
 320         /* Check if we leave a signal handler; this can happen when
 321          * calling longjmp() in the handler */
 322         CLG_(run_post_signal_on_call_stack_bottom)();
 323     }
 324
 325     lower_entry =
 326         &(CLG_(current_call_stack).entry[CLG_(current_call_stack).sp-1]);
 327
 328     CLG_DEBUG(4,"+ pop_call_stack: frame %d, jcc %p\n",
 329                 CLG_(current_call_stack).sp, lower_entry->jcc);
 330
 331     /* jCC item not any more on real stack: pop */
 332     jcc = lower_entry->jcc;
 333     CLG_(current_state).nonskipped = lower_entry->nonskipped;
 334
 335     if (jcc) {
 336         fn_node* to_fn  = jcc->to->cxt->fn[0];
 337         UInt* pdepth =  CLG_(get_fn_entry)(to_fn->number);
 338         if (CLG_(clo).skip_direct_recursion) {
 339             /* only decrement depth if another function was called */
 340           if (jcc->from->cxt->fn[0] != to_fn) (*pdepth)--;
 341         }
 342         else (*pdepth)--;
 343         depth = *pdepth;
 344
 345         /* add cost difference to sum */
 346         if ( CLG_(add_diff_cost_lz)( CLG_(sets).full, &(jcc->cost),
 347                                     lower_entry->enter_cost,
 348                                     CLG_(current_state).cost) ) {
 349
 350           /* only count this call if it attributed some cost.
 351            * the ret_counter is used to check if a BBCC dump is needed.
 352            */
 353           jcc->from->ret_counter++;
 354         }
 355         CLG_(stat).ret_counter++;
 356
 357         /* restore context */
 358         CLG_(current_state).cxt  = lower_entry->cxt;
 359         CLG_(current_fn_stack).top =
 360           CLG_(current_fn_stack).bottom + lower_entry->fn_sp;
 361         CLG_ASSERT(CLG_(current_state).cxt != 0);
 362
 363         if (depth == 0) function_left(to_fn);
 364     }
 365
 366     /* To allow for an assertion in push_call_stack() */
 367     lower_entry->cxt = 0;
 368
 369     CLG_(current_call_stack).sp--;
 370
 371 #if CLG_ENABLE_DEBUG
 372     CLG_DEBUGIF(1) {
 373         if (CLG_(clo).verbose<4) {
 374             if (jcc) {
 375                 /* popped JCC target first */
 376                 VG_(printf)("- %2d %#lx => ",
 377                             CLG_(current_call_stack).sp,
 378                             bb_addr(jcc->to->bb));
 379                 CLG_(print_addr)(bb_jmpaddr(jcc->from->bb));
 380                 VG_(printf)(", SP %#lx\n",
 381                             CLG_(current_call_stack).entry[CLG_(current_call_stack).sp].sp);
 382                 CLG_(print_cost)(10, CLG_(sets).full, jcc->cost);
 383             }
 384             else
 385                 VG_(printf)("- %2d [Skipped JCC], SP %#lx\n",
 386                             CLG_(current_call_stack).sp,
 387                             CLG_(current_call_stack).entry[CLG_(current_call_stack).sp].sp);
 388         }
 389         else {
 390             VG_(printf)("  Popped ");
 391             CLG_(print_stackentry)(7, CLG_(current_call_stack).sp);
 392             if (jcc) {
 393                 VG_(printf)("       returned to ");
 394                 CLG_(print_addr_ln)(bb_jmpaddr(jcc->from->bb));
 395             }
 396         }
 397     }
 398 #endif
 399
 400 }
 401
 402
 403 /* Unwind enough CallStack items to sync with current stack pointer.
 404  * Returns the number of stack frames unwinded.
 405  */
 406 Int CLG_(unwind_call_stack)(Addr sp, Int minpops)
 407 {
 408     Int csp;
 409     Int unwind_count = 0;
 410     CLG_DEBUG(4,"+ unwind_call_stack(sp %#lx, minpops %d): frame %d\n",
 411               sp, minpops, CLG_(current_call_stack).sp);
 412
 413     /* We pop old stack frames.
 414      * For a call, be p the stack address with return address.
 415      *  - call_stack_esp[] has SP after the CALL: p-4
 416      *  - current sp is after a RET: >= p
 417      */
 418
 419     while( (csp=CLG_(current_call_stack).sp) >0) {
 420         call_entry* top_ce = &(CLG_(current_call_stack).entry[csp-1]);
 421
 422         if ((top_ce->sp < sp) ||
 423             ((top_ce->sp == sp) && minpops>0)) {
 424
 425             minpops--;
 426             unwind_count++;
 427             CLG_(pop_call_stack)();
 428             csp=CLG_(current_call_stack).sp;
 429             continue;
 430         }
 431         break;
 432     }
 433
 434     CLG_DEBUG(4,"- unwind_call_stack\n");
 435     return unwind_count;
 436 }