sewardj | 267100d | 2005-04-24 12:33:12 +0000 | [diff] [blame] | 1 | |
njn | d01fef7 | 2005-03-25 23:35:48 +0000 | [diff] [blame] | 2 | /*--------------------------------------------------------------------*/ |
sewardj | 267100d | 2005-04-24 12:33:12 +0000 | [diff] [blame] | 3 | /*--- Store and compare stack backtraces m_execontext.c ---*/ |
njn | d01fef7 | 2005-03-25 23:35:48 +0000 | [diff] [blame] | 4 | /*--------------------------------------------------------------------*/ |
| 5 | |
| 6 | /* |
| 7 | This file is part of Valgrind, a dynamic binary instrumentation |
| 8 | framework. |
| 9 | |
| 10 | Copyright (C) 2000-2005 Julian Seward |
| 11 | jseward@acm.org |
| 12 | |
| 13 | This program is free software; you can redistribute it and/or |
| 14 | modify it under the terms of the GNU General Public License as |
| 15 | published by the Free Software Foundation; either version 2 of the |
| 16 | License, or (at your option) any later version. |
| 17 | |
| 18 | This program is distributed in the hope that it will be useful, but |
| 19 | WITHOUT ANY WARRANTY; without even the implied warranty of |
| 20 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 21 | General Public License for more details. |
| 22 | |
| 23 | You should have received a copy of the GNU General Public License |
| 24 | along with this program; if not, write to the Free Software |
| 25 | Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 26 | 02111-1307, USA. |
| 27 | |
| 28 | The GNU General Public License is contained in the file COPYING. |
| 29 | */ |
| 30 | |
njn | c7561b9 | 2005-06-19 01:24:32 +0000 | [diff] [blame] | 31 | #include "pub_core_basics.h" |
njn | d01fef7 | 2005-03-25 23:35:48 +0000 | [diff] [blame] | 32 | #include "pub_core_execontext.h" |
njn | 132bfcc | 2005-06-04 19:16:06 +0000 | [diff] [blame] | 33 | #include "pub_core_libcassert.h" |
njn | 24a6efb | 2005-06-20 03:36:51 +0000 | [diff] [blame] | 34 | #include "pub_core_libcprint.h" // For VG_(message)() |
njn | af1d7df | 2005-06-11 01:31:52 +0000 | [diff] [blame] | 35 | #include "pub_core_mallocfree.h" |
njn | 2024234 | 2005-05-16 23:31:24 +0000 | [diff] [blame] | 36 | #include "pub_core_options.h" |
njn | 31513b4 | 2005-06-01 03:09:59 +0000 | [diff] [blame] | 37 | #include "pub_core_profile.h" |
njn | d0d7c1f | 2005-06-21 00:33:19 +0000 | [diff] [blame] | 38 | #include "pub_core_stacktrace.h" |
njn | d01fef7 | 2005-03-25 23:35:48 +0000 | [diff] [blame] | 39 | |
| 40 | /*------------------------------------------------------------*/ |
| 41 | /*--- Low-level ExeContext storage. ---*/ |
| 42 | /*------------------------------------------------------------*/ |
| 43 | |
sewardj | ef52b9d | 2005-06-28 00:12:31 +0000 | [diff] [blame^] | 44 | /* The first 4 IP values are used in comparisons to remove duplicate errors, |
njn | d01fef7 | 2005-03-25 23:35:48 +0000 | [diff] [blame] | 45 | and for comparing against suppression specifications. The rest are |
| 46 | purely informational (but often important). */ |
| 47 | |
| 48 | struct _ExeContext { |
| 49 | struct _ExeContext * next; |
| 50 | /* Variable-length array. The size is VG_(clo_backtrace_size); at |
| 51 | least 1, at most VG_DEEPEST_BACKTRACE. [0] is the current IP, |
| 52 | [1] is its caller, [2] is the caller of [1], etc. */ |
| 53 | Addr ips[0]; |
| 54 | }; |
| 55 | |
| 56 | /* Number of lists in which we keep track of ExeContexts. Should be |
| 57 | prime. */ |
| 58 | #define N_EC_LISTS 4999 /* a prime number */ |
| 59 | |
| 60 | /* The idea is only to ever store any one context once, so as to save |
| 61 | space and make exact comparisons faster. */ |
| 62 | |
| 63 | static ExeContext* ec_list[N_EC_LISTS]; |
| 64 | |
| 65 | /* Stats only: the number of times the system was searched to locate a |
| 66 | context. */ |
| 67 | static UInt ec_searchreqs; |
| 68 | |
| 69 | /* Stats only: the number of full context comparisons done. */ |
| 70 | static UInt ec_searchcmps; |
| 71 | |
| 72 | /* Stats only: total number of stored contexts. */ |
| 73 | static UInt ec_totstored; |
| 74 | |
| 75 | /* Number of 2, 4 and (fast) full cmps done. */ |
| 76 | static UInt ec_cmp2s; |
| 77 | static UInt ec_cmp4s; |
| 78 | static UInt ec_cmpAlls; |
| 79 | |
| 80 | |
| 81 | /*------------------------------------------------------------*/ |
| 82 | /*--- Exported functions. ---*/ |
| 83 | /*------------------------------------------------------------*/ |
| 84 | |
| 85 | |
| 86 | /* Initialise this subsystem. */ |
| 87 | static void init_ExeContext_storage ( void ) |
| 88 | { |
| 89 | Int i; |
| 90 | static Bool init_done = False; |
| 91 | if (init_done) |
| 92 | return; |
| 93 | ec_searchreqs = 0; |
| 94 | ec_searchcmps = 0; |
| 95 | ec_totstored = 0; |
| 96 | ec_cmp2s = 0; |
| 97 | ec_cmp4s = 0; |
| 98 | ec_cmpAlls = 0; |
| 99 | for (i = 0; i < N_EC_LISTS; i++) |
| 100 | ec_list[i] = NULL; |
| 101 | init_done = True; |
| 102 | } |
| 103 | |
| 104 | |
| 105 | /* Print stats. */ |
| 106 | void VG_(print_ExeContext_stats) ( void ) |
| 107 | { |
| 108 | init_ExeContext_storage(); |
| 109 | VG_(message)(Vg_DebugMsg, |
| 110 | " exectx: %d lists, %d contexts (avg %d per list)", |
| 111 | N_EC_LISTS, ec_totstored, |
| 112 | ec_totstored / N_EC_LISTS |
| 113 | ); |
| 114 | VG_(message)(Vg_DebugMsg, |
| 115 | " exectx: %d searches, %d full compares (%d per 1000)", |
| 116 | ec_searchreqs, ec_searchcmps, |
| 117 | ec_searchreqs == 0 |
| 118 | ? 0 |
| 119 | : (UInt)( (((ULong)ec_searchcmps) * 1000) |
| 120 | / ((ULong)ec_searchreqs )) |
| 121 | ); |
| 122 | VG_(message)(Vg_DebugMsg, |
| 123 | " exectx: %d cmp2, %d cmp4, %d cmpAll", |
| 124 | ec_cmp2s, ec_cmp4s, ec_cmpAlls |
| 125 | ); |
| 126 | } |
| 127 | |
| 128 | |
| 129 | /* Print an ExeContext. */ |
| 130 | void VG_(pp_ExeContext) ( ExeContext* ec ) |
| 131 | { |
| 132 | VG_(pp_StackTrace)( ec->ips, VG_(clo_backtrace_size) ); |
| 133 | } |
| 134 | |
| 135 | |
| 136 | /* Compare two ExeContexts, comparing all callers. */ |
| 137 | Bool VG_(eq_ExeContext) ( VgRes res, ExeContext* e1, ExeContext* e2 ) |
| 138 | { |
| 139 | if (e1 == NULL || e2 == NULL) |
| 140 | return False; |
| 141 | switch (res) { |
| 142 | case Vg_LowRes: |
| 143 | /* Just compare the top two callers. */ |
| 144 | ec_cmp2s++; |
| 145 | if (e1->ips[0] != e2->ips[0]) return False; |
| 146 | |
| 147 | if (VG_(clo_backtrace_size) < 2) return True; |
| 148 | if (e1->ips[1] != e2->ips[1]) return False; |
| 149 | return True; |
| 150 | |
| 151 | case Vg_MedRes: |
| 152 | /* Just compare the top four callers. */ |
| 153 | ec_cmp4s++; |
| 154 | if (e1->ips[0] != e2->ips[0]) return False; |
| 155 | |
| 156 | if (VG_(clo_backtrace_size) < 2) return True; |
| 157 | if (e1->ips[1] != e2->ips[1]) return False; |
| 158 | |
| 159 | if (VG_(clo_backtrace_size) < 3) return True; |
| 160 | if (e1->ips[2] != e2->ips[2]) return False; |
| 161 | |
| 162 | if (VG_(clo_backtrace_size) < 4) return True; |
| 163 | if (e1->ips[3] != e2->ips[3]) return False; |
| 164 | return True; |
| 165 | |
| 166 | case Vg_HighRes: |
| 167 | ec_cmpAlls++; |
| 168 | /* Compare them all -- just do pointer comparison. */ |
| 169 | if (e1 != e2) return False; |
| 170 | return True; |
| 171 | |
| 172 | default: |
| 173 | VG_(core_panic)("VG_(eq_ExeContext): unrecognised VgRes"); |
| 174 | } |
| 175 | } |
| 176 | |
| 177 | /* This guy is the head honcho here. Take a snapshot of the client's |
| 178 | stack. Search our collection of ExeContexts to see if we already |
| 179 | have it, and if not, allocate a new one. Either way, return a |
| 180 | pointer to the context. If there is a matching context we |
| 181 | guarantee to not allocate a new one. Thus we never store |
| 182 | duplicates, and so exact equality can be quickly done as equality |
| 183 | on the returned ExeContext* values themselves. Inspired by Hugs's |
| 184 | Text type. |
| 185 | */ |
| 186 | ExeContext* VG_(record_ExeContext) ( ThreadId tid ) |
| 187 | { |
| 188 | Int i; |
| 189 | Addr ips[VG_DEEPEST_BACKTRACE]; |
| 190 | Bool same; |
| 191 | UWord hash; |
| 192 | ExeContext* new_ec; |
| 193 | ExeContext* list; |
| 194 | |
| 195 | VGP_PUSHCC(VgpExeContext); |
| 196 | |
| 197 | init_ExeContext_storage(); |
| 198 | vg_assert(VG_(clo_backtrace_size) >= 1 |
| 199 | && VG_(clo_backtrace_size) <= VG_DEEPEST_BACKTRACE); |
| 200 | |
| 201 | VG_(get_StackTrace)( tid, ips, VG_(clo_backtrace_size) ); |
| 202 | |
| 203 | /* Now figure out if we've seen this one before. First hash it so |
| 204 | as to determine the list number. */ |
| 205 | |
| 206 | hash = 0; |
| 207 | for (i = 0; i < VG_(clo_backtrace_size); i++) { |
| 208 | hash ^= ips[i]; |
| 209 | hash = (hash << 29) | (hash >> 3); |
| 210 | } |
| 211 | hash = hash % N_EC_LISTS; |
| 212 | |
| 213 | /* And (the expensive bit) look a matching entry in the list. */ |
| 214 | |
| 215 | ec_searchreqs++; |
| 216 | |
| 217 | list = ec_list[hash]; |
| 218 | |
| 219 | while (True) { |
| 220 | if (list == NULL) break; |
| 221 | ec_searchcmps++; |
| 222 | same = True; |
| 223 | for (i = 0; i < VG_(clo_backtrace_size); i++) { |
| 224 | if (list->ips[i] != ips[i]) { |
| 225 | same = False; |
| 226 | break; |
| 227 | } |
| 228 | } |
| 229 | if (same) break; |
| 230 | list = list->next; |
| 231 | } |
| 232 | |
| 233 | if (list != NULL) { |
| 234 | /* Yay! We found it. */ |
| 235 | VGP_POPCC(VgpExeContext); |
| 236 | return list; |
| 237 | } |
| 238 | |
| 239 | /* Bummer. We have to allocate a new context record. */ |
| 240 | ec_totstored++; |
| 241 | |
| 242 | new_ec = VG_(arena_malloc)( VG_AR_EXECTXT, |
| 243 | sizeof(struct _ExeContext *) |
| 244 | + VG_(clo_backtrace_size) * sizeof(Addr) ); |
| 245 | |
| 246 | for (i = 0; i < VG_(clo_backtrace_size); i++) |
| 247 | new_ec->ips[i] = ips[i]; |
| 248 | |
| 249 | new_ec->next = ec_list[hash]; |
| 250 | ec_list[hash] = new_ec; |
| 251 | |
| 252 | VGP_POPCC(VgpExeContext); |
| 253 | return new_ec; |
| 254 | } |
| 255 | |
| 256 | StackTrace VG_(extract_StackTrace) ( ExeContext* e ) |
| 257 | { |
| 258 | return e->ips; |
| 259 | } |
| 260 | |
| 261 | /*--------------------------------------------------------------------*/ |
sewardj | 267100d | 2005-04-24 12:33:12 +0000 | [diff] [blame] | 262 | /*--- end m_execontext.c ---*/ |
njn | d01fef7 | 2005-03-25 23:35:48 +0000 | [diff] [blame] | 263 | /*--------------------------------------------------------------------*/ |