mirror of
https://github.com/Zenithsiz/ftmemsim-valgrind.git
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8138f264e0
now that we have the additional complication of multiple threads. git-svn-id: svn://svn.valgrind.org/valgrind/trunk@64
260 lines
7.5 KiB
C
260 lines
7.5 KiB
C
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/*--------------------------------------------------------------------*/
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/*--- Storage, and equality on, execution contexts (backtraces). ---*/
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/*--- vg_execontext.c ---*/
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/*--------------------------------------------------------------------*/
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/*
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This file is part of Valgrind, an x86 protected-mode emulator
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designed for debugging and profiling binaries on x86-Unixes.
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Copyright (C) 2000-2002 Julian Seward
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jseward@acm.org
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Julian_Seward@muraroa.demon.co.uk
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307, USA.
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The GNU General Public License is contained in the file LICENSE.
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*/
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#include "vg_include.h"
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#include "vg_constants.h"
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/*------------------------------------------------------------*/
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/*--- Low-level ExeContext storage. ---*/
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/*------------------------------------------------------------*/
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/* The idea is only to ever store any one context once, so as to save
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space and make exact comparisons faster. */
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static ExeContext* vg_ec_list[VG_N_EC_LISTS];
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/* Stats only: the number of times the system was searched to locate a
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context. */
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static UInt vg_ec_searchreqs;
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/* Stats only: the number of full context comparisons done. */
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static UInt vg_ec_searchcmps;
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/* Stats only: total number of stored contexts. */
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static UInt vg_ec_totstored;
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/* Number of 2, 4 and (fast) full cmps done. */
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static UInt vg_ec_cmp2s;
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static UInt vg_ec_cmp4s;
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static UInt vg_ec_cmpAlls;
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/*------------------------------------------------------------*/
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/*--- Exported functions. ---*/
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/*------------------------------------------------------------*/
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/* Initialise this subsystem. */
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void VG_(init_ExeContext_storage) ( void )
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{
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Int i;
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vg_ec_searchreqs = 0;
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vg_ec_searchcmps = 0;
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vg_ec_totstored = 0;
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vg_ec_cmp2s = 0;
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vg_ec_cmp4s = 0;
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vg_ec_cmpAlls = 0;
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for (i = 0; i < VG_N_EC_LISTS; i++)
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vg_ec_list[i] = NULL;
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}
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/* Show stats. */
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void VG_(show_ExeContext_stats) ( void )
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{
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VG_(message)(Vg_DebugMsg,
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"exectx: %d lists, %d contexts (avg %d per list)",
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VG_N_EC_LISTS, vg_ec_totstored,
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vg_ec_totstored / VG_N_EC_LISTS
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);
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VG_(message)(Vg_DebugMsg,
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"exectx: %d searches, %d full compares (%d per 1000)",
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vg_ec_searchreqs, vg_ec_searchcmps,
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vg_ec_searchreqs == 0
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? 0
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: (UInt)( (((ULong)vg_ec_searchcmps) * 1000)
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/ ((ULong)vg_ec_searchreqs ))
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);
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VG_(message)(Vg_DebugMsg,
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"exectx: %d cmp2, %d cmp4, %d cmpAll",
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vg_ec_cmp2s, vg_ec_cmp4s, vg_ec_cmpAlls
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);
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}
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/* Print an ExeContext. */
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void VG_(pp_ExeContext) ( ExeContext* e )
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{
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VG_(mini_stack_dump) ( e );
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}
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/* Compare two ExeContexts, comparing all callers. */
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Bool VG_(eq_ExeContext_all) ( ExeContext* e1, ExeContext* e2 )
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{
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vg_ec_cmpAlls++;
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/* Just do pointer comparison. */
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if (e1 != e2) return False;
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return True;
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}
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/* Compare two ExeContexts, just comparing the top two callers. */
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Bool VG_(eq_ExeContext_top2) ( ExeContext* e1, ExeContext* e2 )
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{
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vg_ec_cmp2s++;
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if (e1->eips[0] != e2->eips[0]
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|| e1->eips[1] != e2->eips[1]) return False;
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return True;
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}
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/* Compare two ExeContexts, just comparing the top four callers. */
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Bool VG_(eq_ExeContext_top4) ( ExeContext* e1, ExeContext* e2 )
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{
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vg_ec_cmp4s++;
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if (e1->eips[0] != e2->eips[0]
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|| e1->eips[1] != e2->eips[1]) return False;
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if (VG_(clo_backtrace_size) < 3) return True;
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if (e1->eips[2] != e2->eips[2]) return False;
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if (VG_(clo_backtrace_size) < 4) return True;
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if (e1->eips[3] != e2->eips[3]) return False;
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return True;
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}
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/* This guy is the head honcho here. Take a snapshot of the client's
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stack. Search our collection of ExeContexts to see if we already
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have it, and if not, allocate a new one. Either way, return a
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pointer to the context. If there is a matching context we
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guarantee to not allocate a new one. Thus we never store
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duplicates, and so exact equality can be quickly done as equality
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on the returned ExeContext* values themselves. Inspired by Hugs's
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Text type.
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In order to be thread-safe, we pass in the thread's %EIP and %EBP.
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*/
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ExeContext* VG_(get_ExeContext) ( Bool skip_top_frame,
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Addr eip, Addr ebp )
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{
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Int i;
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Addr eips[VG_DEEPEST_BACKTRACE];
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Bool same;
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UInt hash;
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ExeContext* new_ec;
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ExeContext* list;
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VGP_PUSHCC(VgpExeContext);
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vg_assert(VG_(clo_backtrace_size) >= 2
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&& VG_(clo_backtrace_size) <= VG_DEEPEST_BACKTRACE);
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/* First snaffle %EIPs from the client's stack into eips[0
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.. VG_(clo_backtrace_size)-1], putting zeroes in when the trail
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goes cold. */
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for (i = 0; i < VG_(clo_backtrace_size); i++)
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eips[i] = 0;
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# define GET_CALLER(lval) \
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if (ebp != 0 && VGM_(check_readable)(ebp, 8, NULL)) { \
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lval = ((UInt*)ebp)[1]; /* ret addr */ \
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ebp = ((UInt*)ebp)[0]; /* old ebp */ \
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} else { \
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lval = ebp = 0; \
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}
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if (skip_top_frame) {
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for (i = 0; i < VG_(clo_backtrace_size); i++)
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GET_CALLER(eips[i]);
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} else {
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eips[0] = eip;
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for (i = 1; i < VG_(clo_backtrace_size); i++)
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GET_CALLER(eips[i]);
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}
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# undef GET_CALLER
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/* Now figure out if we've seen this one before. First hash it so
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as to determine the list number. */
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hash = 0;
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for (i = 0; i < VG_(clo_backtrace_size); i++) {
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hash ^= (UInt)eips[i];
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hash = (hash << 29) | (hash >> 3);
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}
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hash = hash % VG_N_EC_LISTS;
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/* And (the expensive bit) look a matching entry in the list. */
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vg_ec_searchreqs++;
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list = vg_ec_list[hash];
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while (True) {
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if (list == NULL) break;
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vg_ec_searchcmps++;
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same = True;
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for (i = 0; i < VG_(clo_backtrace_size); i++) {
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if (list->eips[i] != eips[i]) {
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same = False;
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break;
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}
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}
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if (same) break;
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list = list->next;
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}
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if (list != NULL) {
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/* Yay! We found it. */
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VGP_POPCC;
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return list;
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}
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/* Bummer. We have to allocate a new context record. */
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vg_ec_totstored++;
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new_ec
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= VG_(malloc)(
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VG_AR_EXECTXT,
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sizeof(struct _ExeContextRec *)
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+ VG_(clo_backtrace_size) * sizeof(Addr)
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);
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for (i = 0; i < VG_(clo_backtrace_size); i++)
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new_ec->eips[i] = eips[i];
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new_ec->next = vg_ec_list[hash];
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vg_ec_list[hash] = new_ec;
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VGP_POPCC;
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return new_ec;
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}
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/*--------------------------------------------------------------------*/
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/*--- end vg_execontext.c ---*/
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/*--------------------------------------------------------------------*/
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