callgrind/bb.c

   1 /*--------------------------------------------------------------------*/
   2 /*--- Callgrind                                                    ---*/
   3 /*---                                                         bb.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, see <http://www.gnu.org/licenses/>.
  23
  24    The GNU General Public License is contained in the file COPYING.
  25 */
  26
  27 #include "global.h"
  28
  29 /*------------------------------------------------------------*/
  30 /*--- Basic block (BB) operations                          ---*/
  31 /*------------------------------------------------------------*/
  32
  33 /* BB hash, resizable */
  34 bb_hash bbs;
  35
  36 void CLG_(init_bb_hash)(void)
  37 {
  38    Int i;
  39
  40    bbs.size    = 8437;
  41    bbs.entries = 0;
  42    bbs.table = (BB**) CLG_MALLOC("cl.bb.ibh.1",
  43                                  bbs.size * sizeof(BB*));
  44
  45    for (i = 0; i < bbs.size; i++) bbs.table[i] = NULL;
  46 }
  47
  48 bb_hash* CLG_(get_bb_hash)(void)
  49 {
  50   return &bbs;
  51 }
  52
  53 /* The hash stores BBs according to
  54  * - ELF object (is 0 for code in anonymous mapping)
  55  * - BB base as object file offset
  56  */
  57 static __inline__
  58 UInt bb_hash_idx(obj_node* obj, PtrdiffT offset, UInt size)
  59 {
  60   return (((Addr)obj) + offset) % size;
  61 }
  62
  63 /* double size of bb table  */
  64 static
  65 void resize_bb_table(void)
  66 {
  67     Int i, new_size, conflicts1 = 0, conflicts2 = 0;
  68     BB **new_table, *curr, *next;
  69     UInt new_idx;
  70
  71     new_size  = 2* bbs.size +3;
  72     new_table = (BB**) CLG_MALLOC("cl.bb.rbt.1",
  73                                   new_size * sizeof(BB*));
  74
  75     for (i = 0; i < new_size; i++)
  76       new_table[i] = NULL;
  77
  78     for (i = 0; i < bbs.size; i++) {
  79         if (bbs.table[i] == NULL) continue;
  80
  81         curr = bbs.table[i];
  82         while (NULL != curr) {
  83             next = curr->next;
  84
  85             new_idx = bb_hash_idx(curr->obj, curr->offset, new_size);
  86
  87             curr->next = new_table[new_idx];
  88             new_table[new_idx] = curr;
  89             if (curr->next) {
  90                 conflicts1++;
  91                 if (curr->next->next)
  92                     conflicts2++;
  93             }
  94
  95             curr = next;
  96         }
  97     }
  98
  99     VG_(free)(bbs.table);
 100
 101
 102     CLG_DEBUG(0, "Resize BB Hash: %u => %d (entries %u, conflicts %d/%d)\n",
 103              bbs.size, new_size,
 104              bbs.entries, conflicts1, conflicts2);
 105
 106     bbs.size  = new_size;
 107     bbs.table = new_table;
 108     CLG_(stat).bb_hash_resizes++;
 109 }
 110
 111
 112 /**
 113  * Allocate new BB structure (including space for event type list)
 114  * Not initialized:
 115  * - instr_len, cost_count, instr[]
 116  */
 117 static BB* new_bb(obj_node* obj, PtrdiffT offset,
 118                   UInt instr_count, UInt cjmp_count, Bool cjmp_inverted)
 119 {
 120    BB* bb;
 121    UInt idx, size;
 122
 123    /* check fill degree of bb hash table and resize if needed (>80%) */
 124    bbs.entries++;
 125    if (10 * bbs.entries / bbs.size > 8)
 126        resize_bb_table();
 127
 128    size = sizeof(BB) + instr_count * sizeof(InstrInfo)
 129                      + (cjmp_count+1) * sizeof(CJmpInfo);
 130    bb = (BB*) CLG_MALLOC("cl.bb.nb.1", size);
 131    VG_(memset)(bb, 0, size);
 132
 133    bb->obj        = obj;
 134    bb->offset     = offset;
 135
 136    bb->instr_count = instr_count;
 137    bb->cjmp_count  = cjmp_count;
 138    bb->cjmp_inverted = cjmp_inverted;
 139    bb->jmp         = (CJmpInfo*) &(bb->instr[instr_count]);
 140    bb->instr_len   = 0;
 141    bb->cost_count  = 0;
 142    bb->sect_kind   = VG_(DebugInfo_sect_kind)(NULL, offset + obj->offset);
 143    bb->fn          = 0;
 144    bb->line        = 0;
 145    bb->is_entry    = 0;
 146    bb->bbcc_list   = 0;
 147    bb->last_bbcc   = 0;
 148
 149    /* insert into BB hash table */
 150    idx = bb_hash_idx(obj, offset, bbs.size);
 151    bb->next = bbs.table[idx];
 152    bbs.table[idx] = bb;
 153
 154    CLG_(stat).distinct_bbs++;
 155
 156 #if CLG_ENABLE_DEBUG
 157    CLG_DEBUGIF(3) {
 158      VG_(printf)("  new_bb (instr %u, jmps %u, inv %s) [now %d]: ",
 159                  instr_count, cjmp_count,
 160                  cjmp_inverted ? "yes":"no",
 161                  CLG_(stat).distinct_bbs);
 162       CLG_(print_bb)(0, bb);
 163       VG_(printf)("\n");
 164    }
 165 #endif
 166
 167    CLG_(get_fn_node)(bb);
 168
 169    return bb;
 170 }
 171
 172
 173 /* get the BB structure for a BB start address */
 174 static __inline__
 175 BB* lookup_bb(obj_node* obj, PtrdiffT offset)
 176 {
 177     BB* bb;
 178     Int idx;
 179
 180     idx = bb_hash_idx(obj, offset, bbs.size);
 181     bb = bbs.table[idx];
 182
 183     while(bb) {
 184       if ((bb->obj == obj) && (bb->offset == offset)) break;
 185       bb = bb->next;
 186     }
 187
 188     CLG_DEBUG(5, "  lookup_bb (Obj %s, off %#lx): %p\n",
 189               obj->name, (UWord)offset, bb);
 190     return bb;
 191 }
 192
 193 static __inline__
 194 obj_node* obj_of_address(Addr addr)
 195 {
 196   obj_node* obj;
 197   DebugInfo* di;
 198   PtrdiffT offset;
 199
 200   DiEpoch ep = VG_(current_DiEpoch)();
 201   di = VG_(find_DebugInfo)(ep, addr);
 202   obj = CLG_(get_obj_node)( di );
 203
 204   /* Update symbol offset in object if remapped */
 205   /* FIXME (or at least check this) 2008 Feb 19: 'offset' is
 206      only correct for text symbols, not for data symbols */
 207   offset = di ? VG_(DebugInfo_get_text_bias)(di):0;
 208   if (obj->offset != offset) {
 209       Addr start = di ? VG_(DebugInfo_get_text_avma)(di) : 0;
 210
 211       CLG_DEBUG(0, "Mapping changed for '%s': %#lx -> %#lx\n",
 212                 obj->name, obj->start, start);
 213
 214       /* Size should be the same, and offset diff == start diff */
 215       CLG_ASSERT( obj->size == (di ? VG_(DebugInfo_get_text_size)(di) : 0) );
 216       CLG_ASSERT( obj->start - start == obj->offset - offset );
 217       obj->offset = offset;
 218       obj->start = start;
 219   }
 220
 221   return obj;
 222 }
 223
 224 /* Get the BB structure for a BB start address.
 225  * If the BB has to be created, the IRBB is needed to
 226  * compute the event type list for costs, and seen_before is
 227  * set to False. Otherwise, seen_before is set to True.
 228  *
 229  * BBs are never discarded. There are 2 cases where this function
 230  * is called from CLG_(instrument)() and a BB already exists:
 231  * - The instrumented version was removed from Valgrinds TT cache
 232  * - The ELF object of the BB was unmapped and mapped again.
 233  *   This involves a possibly different address, but is handled by
 234  *   looking up a BB keyed by (obj_node, file offset).
 235  *
 236  * bbIn==0 is possible for artificial BB without real code.
 237  * Such a BB is created when returning to an unknown function.
 238  */
 239 BB* CLG_(get_bb)(Addr addr, IRSB* bbIn, /*OUT*/ Bool *seen_before)
 240 {
 241   BB*   bb;
 242   obj_node* obj;
 243   UInt n_instrs, n_jmps;
 244   Bool cjmp_inverted = False;
 245
 246   CLG_DEBUG(5, "+ get_bb(BB %#lx)\n", addr);
 247
 248   obj = obj_of_address(addr);
 249   bb = lookup_bb(obj, addr - obj->offset);
 250
 251   n_instrs = 0;
 252   n_jmps = 0;
 253   CLG_(collectBlockInfo)(bbIn, &n_instrs, &n_jmps, &cjmp_inverted);
 254
 255   *seen_before = bb ? True : False;
 256   if (*seen_before) {
 257     if (bb->instr_count != n_instrs) {
 258       VG_(message)(Vg_DebugMsg,
 259                    "ERROR: BB Retranslation Mismatch at BB %#lx\n", addr);
 260       VG_(message)(Vg_DebugMsg,
 261                    "  new: Obj %s, Off %#lx, BBOff %#lx, Instrs %u\n",
 262                    obj->name, (UWord)obj->offset,
 263                    addr - obj->offset, n_instrs);
 264       VG_(message)(Vg_DebugMsg,
 265                    "  old: Obj %s, Off %#lx, BBOff %#lx, Instrs %u\n",
 266                    bb->obj->name, (UWord)bb->obj->offset,
 267                    (UWord)bb->offset, bb->instr_count);
 268       CLG_ASSERT(bb->instr_count == n_instrs );
 269     }
 270     CLG_ASSERT(bb->cjmp_count == n_jmps );
 271     CLG_(stat).bb_retranslations++;
 272
 273     CLG_DEBUG(5, "- get_bb(BB %#lx): seen before.\n", addr);
 274     return bb;
 275   }
 276
 277   bb = new_bb(obj, addr - obj->offset, n_instrs, n_jmps, cjmp_inverted);
 278
 279   CLG_DEBUG(5, "- get_bb(BB %#lx)\n", addr);
 280
 281   return bb;
 282 }
 283
 284 /* Delete the BB info for the bb with unredirected entry-point
 285    address 'addr'. */
 286 void CLG_(delete_bb)(Addr addr)
 287 {
 288     BB  *bb, *bp;
 289     Int idx, size;
 290
 291     obj_node* obj = obj_of_address(addr);
 292     PtrdiffT offset = addr - obj->offset;
 293
 294     idx = bb_hash_idx(obj, offset, bbs.size);
 295     bb = bbs.table[idx];
 296
 297     /* bb points at the current bb under consideration, and bp is the
 298        one before. */
 299     bp = NULL;
 300     while(bb) {
 301       if ((bb->obj == obj) && (bb->offset == offset)) break;
 302       bp = bb;
 303       bb = bb->next;
 304     }
 305
 306     if (bb == NULL) {
 307         CLG_DEBUG(3, "  delete_bb (Obj %s, off %#lx): NOT FOUND\n",
 308                   obj->name, (UWord)offset);
 309
 310         /* we didn't find it.
 311          * this happens when callgrinds instrumentation mode
 312          * was off at BB translation time, ie. no BB was created.
 313          */
 314         return;
 315     }
 316
 317     /* unlink it from hash table */
 318
 319     if (bp == NULL) {
 320        /* we found the first one in the list. */
 321        tl_assert(bb == bbs.table[idx]);
 322        bbs.table[idx] = bb->next;
 323     } else {
 324        tl_assert(bb != bbs.table[idx]);
 325        bp->next = bb->next;
 326     }
 327
 328     CLG_DEBUG(3, "  delete_bb (Obj %s, off %#lx): %p, BBCC head: %p\n",
 329               obj->name, (UWord)offset, bb, bb->bbcc_list);
 330
 331     if (bb->bbcc_list == 0) {
 332         /* can be safely deleted */
 333
 334         /* Fill the block up with junk and then free it, so we will
 335            hopefully get a segfault if it is used again by mistake. */
 336         size = sizeof(BB)
 337             + bb->instr_count * sizeof(InstrInfo)
 338             + (bb->cjmp_count+1) * sizeof(CJmpInfo);
 339         VG_(memset)( bb, 0xAA, size );
 340         CLG_FREE(bb);
 341         return;
 342     }
 343     CLG_DEBUG(3, "  delete_bb: BB in use, can not free!\n");
 344 }