Home | History | Annotate | Download | only in drd
      1 /* -*- mode: C; c-basic-offset: 3; -*- */
      2 /*
      3   This file is part of drd, a thread error detector.
      4 
      5   Copyright (C) 2006-2010 Bart Van Assche <bvanassche (at) acm.org>.
      6 
      7   This program is free software; you can redistribute it and/or
      8   modify it under the terms of the GNU General Public License as
      9   published by the Free Software Foundation; either version 2 of the
     10   License, or (at your option) any later version.
     11 
     12   This program is distributed in the hope that it will be useful, but
     13   WITHOUT ANY WARRANTY; without even the implied warranty of
     14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     15   General Public License for more details.
     16 
     17   You should have received a copy of the GNU General Public License
     18   along with this program; if not, write to the Free Software
     19   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
     20   02111-1307, USA.
     21 
     22   The GNU General Public License is contained in the file COPYING.
     23 */
     24 
     25 
     26 #include "drd_barrier.h"
     27 #include "drd_clientobj.h"
     28 #include "drd_clientreq.h"
     29 #include "drd_cond.h"
     30 #include "drd_error.h"
     31 #include "drd_load_store.h"
     32 #include "drd_malloc_wrappers.h"
     33 #include "drd_mutex.h"
     34 #include "drd_rwlock.h"
     35 #include "drd_segment.h"
     36 #include "drd_semaphore.h"
     37 #include "drd_suppression.h"
     38 #include "drd_thread.h"
     39 #include "libvex_guest_offsets.h"
     40 #include "pub_drd_bitmap.h"
     41 #include "pub_tool_vki.h"         // Must be included before pub_tool_libcproc
     42 #include "pub_tool_basics.h"
     43 #include "pub_tool_debuginfo.h"   // VG_(describe_IP)()
     44 #include "pub_tool_libcassert.h"  // tl_assert()
     45 #include "pub_tool_libcbase.h"    // VG_(strcmp)
     46 #include "pub_tool_libcprint.h"   // VG_(printf)
     47 #include "pub_tool_libcproc.h"
     48 #include "pub_tool_machine.h"
     49 #include "pub_tool_mallocfree.h"  // VG_(malloc)(), VG_(free)()
     50 #include "pub_tool_options.h"     // command line options
     51 #include "pub_tool_replacemalloc.h"
     52 #include "pub_tool_threadstate.h" // VG_(get_running_tid)()
     53 #include "pub_tool_tooliface.h"
     54 #include "pub_tool_aspacemgr.h"   // VG_(am_is_valid_for_client)
     55 
     56 
     57 /* Local variables. */
     58 
     59 static Bool s_free_is_write    = False;
     60 static Bool s_print_stats      = False;
     61 static Bool s_var_info         = False;
     62 static Bool s_show_stack_usage = False;
     63 static Bool s_trace_alloc      = False;
     64 
     65 
     66 /**
     67  * Implement the needs_command_line_options for drd.
     68  */
     69 static Bool DRD_(process_cmd_line_option)(Char* arg)
     70 {
     71    int check_stack_accesses   = -1;
     72    int exclusive_threshold_ms = -1;
     73    int first_race_only        = -1;
     74    int report_signal_unlocked = -1;
     75    int segment_merging        = -1;
     76    int segment_merge_interval = -1;
     77    int shared_threshold_ms    = -1;
     78    int show_confl_seg         = -1;
     79    int trace_barrier          = -1;
     80    int trace_clientobj        = -1;
     81    int trace_cond             = -1;
     82    int trace_csw              = -1;
     83    int trace_fork_join        = -1;
     84    int trace_conflict_set     = -1;
     85    int trace_conflict_set_bm  = -1;
     86    int trace_mutex            = -1;
     87    int trace_rwlock           = -1;
     88    int trace_segment          = -1;
     89    int trace_semaphore        = -1;
     90    int trace_suppression      = -1;
     91    Char* trace_address        = 0;
     92 
     93    if      VG_BOOL_CLO(arg, "--check-stack-var",     check_stack_accesses) {}
     94    else if VG_BOOL_CLO(arg, "--drd-stats",           s_print_stats) {}
     95    else if VG_BOOL_CLO(arg, "--first-race-only",     first_race_only) {}
     96    else if VG_BOOL_CLO(arg, "--free-is-write",       s_free_is_write) {}
     97    else if VG_BOOL_CLO(arg,"--report-signal-unlocked",report_signal_unlocked)
     98    {}
     99    else if VG_BOOL_CLO(arg, "--segment-merging",     segment_merging) {}
    100    else if VG_INT_CLO (arg, "--segment-merging-interval", segment_merge_interval)
    101    {}
    102    else if VG_BOOL_CLO(arg, "--show-confl-seg",      show_confl_seg) {}
    103    else if VG_BOOL_CLO(arg, "--show-stack-usage",    s_show_stack_usage) {}
    104    else if VG_BOOL_CLO(arg, "--trace-alloc",         s_trace_alloc) {}
    105    else if VG_BOOL_CLO(arg, "--trace-barrier",       trace_barrier) {}
    106    else if VG_BOOL_CLO(arg, "--trace-clientobj",     trace_clientobj) {}
    107    else if VG_BOOL_CLO(arg, "--trace-cond",          trace_cond) {}
    108    else if VG_BOOL_CLO(arg, "--trace-conflict-set",  trace_conflict_set) {}
    109    else if VG_BOOL_CLO(arg, "--trace-conflict-set-bm", trace_conflict_set_bm){}
    110    else if VG_BOOL_CLO(arg, "--trace-csw",           trace_csw) {}
    111    else if VG_BOOL_CLO(arg, "--trace-fork-join",     trace_fork_join) {}
    112    else if VG_BOOL_CLO(arg, "--trace-mutex",         trace_mutex) {}
    113    else if VG_BOOL_CLO(arg, "--trace-rwlock",        trace_rwlock) {}
    114    else if VG_BOOL_CLO(arg, "--trace-segment",       trace_segment) {}
    115    else if VG_BOOL_CLO(arg, "--trace-semaphore",     trace_semaphore) {}
    116    else if VG_BOOL_CLO(arg, "--trace-suppr",         trace_suppression) {}
    117    else if VG_BOOL_CLO(arg, "--var-info",            s_var_info) {}
    118    else if VG_INT_CLO (arg, "--exclusive-threshold", exclusive_threshold_ms) {}
    119    else if VG_INT_CLO (arg, "--shared-threshold",    shared_threshold_ms)    {}
    120    else if VG_STR_CLO (arg, "--trace-addr",          trace_address) {}
    121    else
    122       return VG_(replacement_malloc_process_cmd_line_option)(arg);
    123 
    124    if (check_stack_accesses != -1)
    125       DRD_(set_check_stack_accesses)(check_stack_accesses);
    126    if (exclusive_threshold_ms != -1)
    127    {
    128       DRD_(mutex_set_lock_threshold)(exclusive_threshold_ms);
    129       DRD_(rwlock_set_exclusive_threshold)(exclusive_threshold_ms);
    130    }
    131    if (first_race_only != -1)
    132    {
    133       DRD_(set_first_race_only)(first_race_only);
    134    }
    135    if (report_signal_unlocked != -1)
    136    {
    137       DRD_(cond_set_report_signal_unlocked)(report_signal_unlocked);
    138    }
    139    if (shared_threshold_ms != -1)
    140    {
    141       DRD_(rwlock_set_shared_threshold)(shared_threshold_ms);
    142    }
    143    if (segment_merging != -1)
    144       DRD_(thread_set_segment_merging)(segment_merging);
    145    if (segment_merge_interval != -1)
    146       DRD_(thread_set_segment_merge_interval)(segment_merge_interval);
    147    if (show_confl_seg != -1)
    148       DRD_(set_show_conflicting_segments)(show_confl_seg);
    149    if (trace_address)
    150    {
    151       const Addr addr = VG_(strtoll16)(trace_address, 0);
    152       DRD_(start_tracing_address_range)(addr, addr + 1);
    153    }
    154    if (trace_barrier != -1)
    155       DRD_(barrier_set_trace)(trace_barrier);
    156    if (trace_clientobj != -1)
    157       DRD_(clientobj_set_trace)(trace_clientobj);
    158    if (trace_cond != -1)
    159       DRD_(cond_set_trace)(trace_cond);
    160    if (trace_csw != -1)
    161       DRD_(thread_trace_context_switches)(trace_csw);
    162    if (trace_fork_join != -1)
    163       DRD_(thread_set_trace_fork_join)(trace_fork_join);
    164    if (trace_conflict_set != -1)
    165       DRD_(thread_trace_conflict_set)(trace_conflict_set);
    166    if (trace_conflict_set_bm != -1)
    167       DRD_(thread_trace_conflict_set_bm)(trace_conflict_set_bm);
    168    if (trace_mutex != -1)
    169       DRD_(mutex_set_trace)(trace_mutex);
    170    if (trace_rwlock != -1)
    171       DRD_(rwlock_set_trace)(trace_rwlock);
    172    if (trace_segment != -1)
    173       DRD_(sg_set_trace)(trace_segment);
    174    if (trace_semaphore != -1)
    175       DRD_(semaphore_set_trace)(trace_semaphore);
    176    if (trace_suppression != -1)
    177       DRD_(suppression_set_trace)(trace_suppression);
    178 
    179    return True;
    180 }
    181 
    182 static void DRD_(print_usage)(void)
    183 {
    184    VG_(printf)(
    185 "    --check-stack-var=yes|no  Whether or not to report data races on\n"
    186 "                              stack variables [no].\n"
    187 "    --exclusive-threshold=<n> Print an error message if any mutex or\n"
    188 "        writer lock is held longer than the specified time (in milliseconds).\n"
    189 "    --first-race-only=yes|no  Only report the first data race that occurs on\n"
    190 "                              a memory location instead of all races [no].\n"
    191 "    --free-is-write=yes|no    Whether to report races between freeing memory\n"
    192 "                              and subsequent accesses of that memory[no].\n"
    193 "    --report-signal-unlocked=yes|no Whether to report calls to\n"
    194 "                              pthread_cond_signal() where the mutex associated\n"
    195 "                              with the signal via pthread_cond_wait() is not\n"
    196 "                              locked at the time the signal is sent [yes].\n"
    197 "    --segment-merging=yes|no  Controls segment merging [yes].\n"
    198 "        Segment merging is an algorithm to limit memory usage of the\n"
    199 "        data race detection algorithm. Disabling segment merging may\n"
    200 "        improve the accuracy of the so-called 'other segments' displayed\n"
    201 "        in race reports but can also trigger an out of memory error.\n"
    202 "    --segment-merging-interval=<n> Perform segment merging every time n new\n"
    203 "        segments have been created. Default: %d.\n"
    204 "    --shared-threshold=<n>    Print an error message if a reader lock\n"
    205 "        is held longer than the specified time (in milliseconds).\n"
    206 "    --show-confl-seg=yes|no   Show conflicting segments in race reports [yes].\n"
    207 "    --show-stack-usage=yes|no Print stack usage at thread exit time [no].\n"
    208 "\n"
    209 "  drd options for monitoring process behavior:\n"
    210 "    --trace-addr=<address>    Trace all load and store activity for the.\n"
    211 "                              specified address [off].\n"
    212 "    --trace-alloc=yes|no      Trace all memory allocations and deallocations\n""                              [no].\n"
    213 "    --trace-barrier=yes|no    Trace all barrier activity [no].\n"
    214 "    --trace-cond=yes|no       Trace all condition variable activity [no].\n"
    215 "    --trace-fork-join=yes|no  Trace all thread fork/join activity [no].\n"
    216 "    --trace-mutex=yes|no      Trace all mutex activity [no].\n"
    217 "    --trace-rwlock=yes|no     Trace all reader-writer lock activity[no].\n"
    218 "    --trace-semaphore=yes|no  Trace all semaphore activity [no].\n",
    219 DRD_(thread_get_segment_merge_interval)()
    220 );
    221 }
    222 
    223 static void DRD_(print_debug_usage)(void)
    224 {
    225    VG_(printf)(
    226 "    --drd-stats=yes|no        Print statistics about DRD activity [no].\n"
    227 "    --trace-clientobj=yes|no  Trace all client object activity [no].\n"
    228 "    --trace-csw=yes|no        Trace all scheduler context switches [no].\n"
    229 "    --trace-conflict-set=yes|no Trace all conflict set updates [no].\n"
    230 "    --trace-conflict-set-bm=yes|no Trace all conflict set bitmap\n"
    231 "                              updates [no]. Note: enabling this option\n"
    232 "                              will generate a lot of output !\n"
    233 "    --trace-segment=yes|no    Trace segment actions [no].\n"
    234 "    --trace-suppr=yes|no      Trace all address suppression actions [no].\n"
    235 );
    236 }
    237 
    238 
    239 //
    240 // Implements the thread-related core callbacks.
    241 //
    242 
    243 static void drd_pre_mem_read(const CorePart part,
    244                              const ThreadId tid,
    245                              Char* const s,
    246                              const Addr a,
    247                              const SizeT size)
    248 {
    249    if (size > 0)
    250    {
    251       DRD_(trace_load)(a, size);
    252    }
    253 }
    254 
    255 static void drd_pre_mem_read_asciiz(const CorePart part,
    256                                     const ThreadId tid,
    257                                     Char* const s,
    258                                     const Addr a)
    259 {
    260    const char* p = (void*)a;
    261    SizeT size = 0;
    262 
    263    // Don't segfault if the string starts in an obviously stupid
    264    // place.  Actually we should check the whole string, not just
    265    // the start address, but that's too much trouble.  At least
    266    // checking the first byte is better than nothing.  See #255009.
    267    if (!VG_(am_is_valid_for_client) (a, 1, VKI_PROT_READ))
    268       return;
    269 
    270    /* Note: the expression '*p' reads client memory and may crash if the */
    271    /* client provided an invalid pointer !                               */
    272    while (*p)
    273    {
    274       p++;
    275       size++;
    276    }
    277    if (size > 0)
    278    {
    279       DRD_(trace_load)(a, size);
    280    }
    281 }
    282 
    283 static void drd_post_mem_write(const CorePart part,
    284                                const ThreadId tid,
    285                                const Addr a,
    286                                const SizeT size)
    287 {
    288    DRD_(thread_set_vg_running_tid)(VG_(get_running_tid)());
    289    if (size > 0)
    290    {
    291       DRD_(trace_store)(a, size);
    292    }
    293 }
    294 
    295 static __inline__
    296 void drd_start_using_mem(const Addr a1, const SizeT len,
    297                          const Bool is_stack_mem)
    298 {
    299    tl_assert(a1 <= a1 + len);
    300 
    301    if (!is_stack_mem && s_trace_alloc)
    302       VG_(message)(Vg_UserMsg, "Started using memory range 0x%lx + %ld%s\n",
    303                    a1, len, DRD_(running_thread_inside_pthread_create)()
    304                    ? " (inside pthread_create())" : "");
    305 
    306    if (UNLIKELY(DRD_(any_address_is_traced)()))
    307    {
    308       DRD_(trace_mem_access)(a1, len, eStart);
    309    }
    310 
    311    if (UNLIKELY(DRD_(running_thread_inside_pthread_create)()))
    312    {
    313       DRD_(start_suppression)(a1, a1 + len, "pthread_create()");
    314    }
    315 }
    316 
    317 static void drd_start_using_mem_w_ecu(const Addr a1,
    318                                       const SizeT len,
    319                                       UInt ec_uniq)
    320 {
    321    drd_start_using_mem(a1, len, False);
    322 }
    323 
    324 static void drd_start_using_mem_w_tid(const Addr a1,
    325                                       const SizeT len,
    326                                       ThreadId tid)
    327 {
    328    drd_start_using_mem(a1, len, False);
    329 }
    330 
    331 static __inline__
    332 void drd_stop_using_mem(const Addr a1, const SizeT len,
    333                         const Bool is_stack_mem)
    334 {
    335    const Addr a2 = a1 + len;
    336 
    337    tl_assert(a1 <= a2);
    338 
    339    if (UNLIKELY(DRD_(any_address_is_traced)()))
    340       DRD_(trace_mem_access)(a1, len, eEnd);
    341 
    342    if (!is_stack_mem && s_trace_alloc)
    343       VG_(message)(Vg_UserMsg, "Stopped using memory range 0x%lx + %ld\n",
    344                    a1, len);
    345 
    346    if (!is_stack_mem || DRD_(get_check_stack_accesses)())
    347    {
    348       DRD_(thread_stop_using_mem)(a1, a2, !is_stack_mem && s_free_is_write);
    349       DRD_(clientobj_stop_using_mem)(a1, a2);
    350       DRD_(suppression_stop_using_mem)(a1, a2);
    351    }
    352    if (!is_stack_mem && s_free_is_write)
    353       DRD_(trace_store)(a1, len);
    354 }
    355 
    356 static __inline__
    357 void drd_stop_using_nonstack_mem(const Addr a1, const SizeT len)
    358 {
    359    drd_stop_using_mem(a1, len, False);
    360 }
    361 
    362 /**
    363  * Discard all information DRD has about memory accesses and client objects
    364  * in the specified address range.
    365  */
    366 void DRD_(clean_memory)(const Addr a1, const SizeT len)
    367 {
    368    const Bool is_stack_memory = DRD_(thread_address_on_any_stack)(a1);
    369    drd_stop_using_mem(a1, len, is_stack_memory);
    370    drd_start_using_mem(a1, len, is_stack_memory);
    371 }
    372 
    373 /**
    374  * Suppress data race reports on all addresses contained in .plt and
    375  * .got.plt sections inside the address range [ a, a + len [. The data in
    376  * these sections is modified by _dl_relocate_object() every time a function
    377  * in a shared library is called for the first time. Since the first call
    378  * to a function in a shared library can happen from a multithreaded context,
    379  * such calls can cause conflicting accesses. See also Ulrich Drepper's
    380  * paper "How to Write Shared Libraries" for more information about relocation
    381  * (http://people.redhat.com/drepper/dsohowto.pdf).
    382  */
    383 static void DRD_(suppress_relocation_conflicts)(const Addr a, const SizeT len)
    384 {
    385    const DebugInfo* di;
    386 
    387 #if 0
    388    VG_(printf)("Evaluating range @ 0x%lx size %ld\n", a, len);
    389 #endif
    390 
    391    for (di = VG_(next_DebugInfo)(0); di; di = VG_(next_DebugInfo)(di))
    392    {
    393       Addr  avma;
    394       SizeT size;
    395 
    396       avma = VG_(DebugInfo_get_plt_avma)(di);
    397       size = VG_(DebugInfo_get_plt_size)(di);
    398       tl_assert((avma && size) || (avma == 0 && size == 0));
    399       if (size > 0)
    400       {
    401 #if 0
    402          VG_(printf)("Suppressing .plt @ 0x%lx size %ld\n", avma, size);
    403 #endif
    404          tl_assert(VG_(DebugInfo_sect_kind)(NULL, 0, avma) == Vg_SectPLT);
    405          DRD_(start_suppression)(avma, avma + size, ".plt");
    406       }
    407 
    408       avma = VG_(DebugInfo_get_gotplt_avma)(di);
    409       size = VG_(DebugInfo_get_gotplt_size)(di);
    410       tl_assert((avma && size) || (avma == 0 && size == 0));
    411       if (size > 0)
    412       {
    413 #if 0
    414          VG_(printf)("Suppressing .got.plt @ 0x%lx size %ld\n", avma, size);
    415 #endif
    416          tl_assert(VG_(DebugInfo_sect_kind)(NULL, 0, avma) == Vg_SectGOTPLT);
    417          DRD_(start_suppression)(avma, avma + size, ".gotplt");
    418       }
    419    }
    420 }
    421 
    422 static
    423 void drd_start_using_mem_w_perms(const Addr a, const SizeT len,
    424                                  const Bool rr, const Bool ww, const Bool xx,
    425                                  ULong di_handle)
    426 {
    427    DRD_(thread_set_vg_running_tid)(VG_(get_running_tid)());
    428 
    429    drd_start_using_mem(a, len, False);
    430 
    431    DRD_(suppress_relocation_conflicts)(a, len);
    432 }
    433 
    434 /* Called by the core when the stack of a thread grows, to indicate that */
    435 /* the addresses in range [ a, a + len [ may now be used by the client.  */
    436 /* Assumption: stacks grow downward.                                     */
    437 static __inline__
    438 void drd_start_using_mem_stack(const Addr a, const SizeT len)
    439 {
    440    DRD_(thread_set_stack_min)(DRD_(thread_get_running_tid)(),
    441                               a - VG_STACK_REDZONE_SZB);
    442    drd_start_using_mem(a - VG_STACK_REDZONE_SZB,
    443                        len + VG_STACK_REDZONE_SZB,
    444                        True);
    445 }
    446 
    447 /* Called by the core when the stack of a thread shrinks, to indicate that */
    448 /* the addresses [ a, a + len [ are no longer accessible for the client.   */
    449 /* Assumption: stacks grow downward.                                       */
    450 static __inline__
    451 void drd_stop_using_mem_stack(const Addr a, const SizeT len)
    452 {
    453    DRD_(thread_set_stack_min)(DRD_(thread_get_running_tid)(),
    454                               a + len - VG_STACK_REDZONE_SZB);
    455    drd_stop_using_mem(a - VG_STACK_REDZONE_SZB, len + VG_STACK_REDZONE_SZB,
    456                       True);
    457 }
    458 
    459 static
    460 Bool on_alt_stack(const Addr a)
    461 {
    462    ThreadId vg_tid;
    463    Addr alt_min;
    464    SizeT alt_size;
    465 
    466    vg_tid = VG_(get_running_tid)();
    467    alt_min = VG_(thread_get_altstack_min)(vg_tid);
    468    alt_size = VG_(thread_get_altstack_size)(vg_tid);
    469    return (SizeT)(a - alt_min) < alt_size;
    470 }
    471 
    472 static
    473 void drd_start_using_mem_alt_stack(const Addr a, const SizeT len)
    474 {
    475    if (!on_alt_stack(a))
    476       drd_start_using_mem_stack(a, len);
    477 }
    478 
    479 static
    480 void drd_stop_using_mem_alt_stack(const Addr a, const SizeT len)
    481 {
    482    if (!on_alt_stack(a))
    483       drd_stop_using_mem_stack(a, len);
    484 }
    485 
    486 /**
    487  * Callback function invoked by the Valgrind core before a signal is delivered.
    488  */
    489 static
    490 void drd_pre_deliver_signal(const ThreadId vg_tid, const Int sigNo,
    491                             const Bool alt_stack)
    492 {
    493    DrdThreadId drd_tid;
    494 
    495    drd_tid = DRD_(VgThreadIdToDrdThreadId)(vg_tid);
    496    DRD_(thread_set_on_alt_stack)(drd_tid, alt_stack);
    497    if (alt_stack)
    498    {
    499       /*
    500        * As soon a signal handler has been invoked on the alternate stack,
    501        * switch to stack memory handling functions that can handle the
    502        * alternate stack.
    503        */
    504       VG_(track_new_mem_stack)(drd_start_using_mem_alt_stack);
    505       VG_(track_die_mem_stack)(drd_stop_using_mem_alt_stack);
    506    }
    507 }
    508 
    509 /**
    510  * Callback function invoked by the Valgrind core after a signal is delivered,
    511  * at least if the signal handler did not longjmp().
    512  */
    513 static
    514 void drd_post_deliver_signal(const ThreadId vg_tid, const Int sigNo)
    515 {
    516    DrdThreadId drd_tid;
    517 
    518    drd_tid = DRD_(VgThreadIdToDrdThreadId)(vg_tid);
    519    DRD_(thread_set_on_alt_stack)(drd_tid, False);
    520    if (DRD_(thread_get_threads_on_alt_stack)() == 0)
    521    {
    522       VG_(track_new_mem_stack)(drd_start_using_mem_stack);
    523       VG_(track_die_mem_stack)(drd_stop_using_mem_stack);
    524    }
    525 }
    526 
    527 /**
    528  * Callback function called by the Valgrind core before a stack area is
    529  * being used by a signal handler.
    530  *
    531  * @param[in] a   Start of address range.
    532  * @param[in] len Address range length.
    533  * @param[in] tid Valgrind thread ID for whom the signal frame is being
    534  *                constructed.
    535  */
    536 static void drd_start_using_mem_stack_signal(const Addr a, const SizeT len,
    537                                              ThreadId tid)
    538 {
    539    DRD_(thread_set_vg_running_tid)(VG_(get_running_tid)());
    540    drd_start_using_mem(a, len, True);
    541 }
    542 
    543 static void drd_stop_using_mem_stack_signal(Addr a, SizeT len)
    544 {
    545    drd_stop_using_mem(a, len, True);
    546 }
    547 
    548 static
    549 void drd_pre_thread_create(const ThreadId creator, const ThreadId created)
    550 {
    551    const DrdThreadId drd_creator = DRD_(VgThreadIdToDrdThreadId)(creator);
    552    tl_assert(created != VG_INVALID_THREADID);
    553    DRD_(thread_pre_create)(drd_creator, created);
    554    if (DRD_(IsValidDrdThreadId)(drd_creator))
    555    {
    556       DRD_(thread_new_segment)(drd_creator);
    557    }
    558    if (DRD_(thread_get_trace_fork_join)())
    559    {
    560       VG_(message)(Vg_DebugMsg,
    561                    "drd_pre_thread_create creator = %d, created = %d\n",
    562                    drd_creator, created);
    563    }
    564 }
    565 
    566 /* Called by Valgrind's core before any loads or stores are performed on */
    567 /* the context of thread "created". At startup, this function is called  */
    568 /* with arguments (0,1).                                                 */
    569 static
    570 void drd_post_thread_create(const ThreadId vg_created)
    571 {
    572    DrdThreadId drd_created;
    573 
    574    tl_assert(vg_created != VG_INVALID_THREADID);
    575 
    576    drd_created = DRD_(thread_post_create)(vg_created);
    577    if (DRD_(thread_get_trace_fork_join)())
    578    {
    579       VG_(message)(Vg_DebugMsg,
    580                    "drd_post_thread_create created = %d\n",
    581                    drd_created);
    582    }
    583    if (! DRD_(get_check_stack_accesses)())
    584    {
    585       DRD_(start_suppression)(DRD_(thread_get_stack_max)(drd_created)
    586                               - DRD_(thread_get_stack_size)(drd_created),
    587                               DRD_(thread_get_stack_max)(drd_created),
    588                               "stack");
    589    }
    590 }
    591 
    592 /* Called after a thread has performed its last memory access. */
    593 static void drd_thread_finished(ThreadId vg_tid)
    594 {
    595    DrdThreadId drd_tid;
    596 
    597    tl_assert(VG_(get_running_tid)() == vg_tid);
    598 
    599    drd_tid = DRD_(VgThreadIdToDrdThreadId)(vg_tid);
    600    if (DRD_(thread_get_trace_fork_join)())
    601    {
    602       VG_(message)(Vg_DebugMsg,
    603                    "drd_thread_finished tid = %d%s\n",
    604                    drd_tid,
    605                    DRD_(thread_get_joinable)(drd_tid)
    606                    ? ""
    607                    : " (which is a detached thread)");
    608    }
    609    if (s_show_stack_usage)
    610    {
    611       const SizeT stack_size = DRD_(thread_get_stack_size)(drd_tid);
    612       const SizeT used_stack
    613          = (DRD_(thread_get_stack_max)(drd_tid)
    614             - DRD_(thread_get_stack_min_min)(drd_tid));
    615       VG_(message)(Vg_UserMsg,
    616                    "thread %d%s finished and used %ld bytes out of %ld"
    617                    " on its stack. Margin: %ld bytes.\n",
    618                    drd_tid,
    619                    DRD_(thread_get_joinable)(drd_tid)
    620                    ? ""
    621                    : " (which is a detached thread)",
    622                    used_stack,
    623                    stack_size,
    624                    stack_size - used_stack);
    625 
    626    }
    627    drd_stop_using_mem(DRD_(thread_get_stack_min)(drd_tid),
    628                       DRD_(thread_get_stack_max)(drd_tid)
    629                       - DRD_(thread_get_stack_min)(drd_tid),
    630                       True);
    631    DRD_(thread_set_record_loads)(drd_tid, False);
    632    DRD_(thread_set_record_stores)(drd_tid, False);
    633    DRD_(thread_finished)(drd_tid);
    634 }
    635 
    636 /*
    637  * Called immediately after fork for the child process only. 'tid' is the
    638  * only surviving thread in the child process. Cleans up thread state.
    639  * See also http://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_atfork.html for a detailed discussion of using fork() in combination with mutexes.
    640  */
    641 static
    642 void drd__atfork_child(ThreadId tid)
    643 {
    644    DRD_(drd_thread_atfork_child)(tid);
    645 }
    646 
    647 
    648 //
    649 // Implementation of the tool interface.
    650 //
    651 
    652 static void DRD_(post_clo_init)(void)
    653 {
    654 #if defined(VGO_linux) || defined(VGO_darwin)
    655    /* fine */
    656 #else
    657    VG_(printf)("\nWARNING: DRD has not yet been tested on this operating system.\n\n");
    658 #  endif
    659 
    660    if (s_var_info)
    661    {
    662       VG_(needs_var_info)();
    663    }
    664 }
    665 
    666 static void drd_start_client_code(const ThreadId tid, const ULong bbs_done)
    667 {
    668    tl_assert(tid == VG_(get_running_tid)());
    669    DRD_(thread_set_vg_running_tid)(tid);
    670 }
    671 
    672 static void DRD_(fini)(Int exitcode)
    673 {
    674    // thread_print_all();
    675    if (VG_(clo_verbosity) == 1 && !VG_(clo_xml)) {
    676       VG_(message)(Vg_UserMsg,
    677                    "For counts of detected and suppressed errors, "
    678                    "rerun with: -v\n");
    679    }
    680 
    681    if (VG_(clo_stats) || s_print_stats)
    682    {
    683       ULong pu = DRD_(thread_get_update_conflict_set_count)();
    684       ULong pu_seg_cr = DRD_(thread_get_update_conflict_set_new_sg_count)();
    685       ULong pu_mtx_cv = DRD_(thread_get_update_conflict_set_sync_count)();
    686       ULong pu_join   = DRD_(thread_get_update_conflict_set_join_count)();
    687 
    688       VG_(message)(Vg_UserMsg,
    689                    "   thread: %lld context switches.\n",
    690                    DRD_(thread_get_context_switch_count)());
    691       VG_(message)(Vg_UserMsg,
    692                    "confl set: %lld full updates and %lld partial updates;\n",
    693 		   DRD_(thread_get_compute_conflict_set_count)(),
    694 		   pu);
    695       VG_(message)(Vg_UserMsg,
    696                    "           %lld partial updates during segment creation,\n",
    697 		   pu_seg_cr);
    698       VG_(message)(Vg_UserMsg,
    699                    "           %lld because of mutex/sema/cond.var. operations,\n",
    700 		   pu_mtx_cv);
    701       VG_(message)(Vg_UserMsg,
    702                    "           %lld because of barrier/rwlock operations and\n",
    703 		   pu - pu_seg_cr - pu_mtx_cv - pu_join);
    704       VG_(message)(Vg_UserMsg,
    705                    "           %lld partial updates because of thread join"
    706 		   " operations.\n",
    707 		   pu_join);
    708       VG_(message)(Vg_UserMsg,
    709                    " segments: created %lld segments, max %lld alive,\n",
    710                    DRD_(sg_get_segments_created_count)(),
    711                    DRD_(sg_get_max_segments_alive_count)());
    712       VG_(message)(Vg_UserMsg,
    713                    "           %lld discard points and %lld merges.\n",
    714                    DRD_(thread_get_discard_ordered_segments_count)(),
    715                    DRD_(sg_get_segment_merge_count)());
    716       VG_(message)(Vg_UserMsg,
    717                    "segmnt cr: %lld mutex, %lld rwlock, %lld semaphore and"
    718                    " %lld barrier.\n",
    719                    DRD_(get_mutex_segment_creation_count)(),
    720                    DRD_(get_rwlock_segment_creation_count)(),
    721                    DRD_(get_semaphore_segment_creation_count)(),
    722                    DRD_(get_barrier_segment_creation_count)());
    723       VG_(message)(Vg_UserMsg,
    724                    "  bitmaps: %lld level one"
    725                    " and %lld level two bitmaps were allocated.\n",
    726                    DRD_(bm_get_bitmap_creation_count)(),
    727                    DRD_(bm_get_bitmap2_creation_count)());
    728       VG_(message)(Vg_UserMsg,
    729                    "    mutex: %lld non-recursive lock/unlock events.\n",
    730                    DRD_(get_mutex_lock_count)());
    731       DRD_(print_malloc_stats)();
    732    }
    733 }
    734 
    735 static
    736 void drd_pre_clo_init(void)
    737 {
    738    // Basic tool stuff.
    739    VG_(details_name)            ("drd");
    740    VG_(details_version)         (NULL);
    741    VG_(details_description)     ("a thread error detector");
    742    VG_(details_copyright_author)("Copyright (C) 2006-2010, and GNU GPL'd,"
    743                                  " by Bart Van Assche.");
    744    VG_(details_bug_reports_to)  (VG_BUGS_TO);
    745 
    746    VG_(basic_tool_funcs)        (DRD_(post_clo_init),
    747                                  DRD_(instrument),
    748                                  DRD_(fini));
    749 
    750    // Command line stuff.
    751    VG_(needs_command_line_options)(DRD_(process_cmd_line_option),
    752                                    DRD_(print_usage),
    753                                    DRD_(print_debug_usage));
    754 
    755    // Error handling.
    756    DRD_(register_error_handlers)();
    757 
    758    // Core event tracking.
    759    VG_(track_pre_mem_read)         (drd_pre_mem_read);
    760    VG_(track_pre_mem_read_asciiz)  (drd_pre_mem_read_asciiz);
    761    VG_(track_post_mem_write)       (drd_post_mem_write);
    762    VG_(track_new_mem_brk)          (drd_start_using_mem_w_tid);
    763    VG_(track_new_mem_mmap)         (drd_start_using_mem_w_perms);
    764    VG_(track_new_mem_stack)        (drd_start_using_mem_stack);
    765    VG_(track_new_mem_stack_signal) (drd_start_using_mem_stack_signal);
    766    VG_(track_new_mem_startup)      (drd_start_using_mem_w_perms);
    767    VG_(track_die_mem_brk)          (drd_stop_using_nonstack_mem);
    768    VG_(track_die_mem_munmap)       (drd_stop_using_nonstack_mem);
    769    VG_(track_die_mem_stack)        (drd_stop_using_mem_stack);
    770    VG_(track_die_mem_stack_signal) (drd_stop_using_mem_stack_signal);
    771    VG_(track_pre_deliver_signal)   (drd_pre_deliver_signal);
    772    VG_(track_post_deliver_signal)  (drd_post_deliver_signal);
    773    VG_(track_start_client_code)    (drd_start_client_code);
    774    VG_(track_pre_thread_ll_create) (drd_pre_thread_create);
    775    VG_(track_pre_thread_first_insn)(drd_post_thread_create);
    776    VG_(track_pre_thread_ll_exit)   (drd_thread_finished);
    777    VG_(atfork)                     (NULL/*pre*/, NULL/*parent*/,
    778 				    drd__atfork_child/*child*/);
    779 
    780    // Other stuff.
    781    DRD_(register_malloc_wrappers)(drd_start_using_mem_w_ecu,
    782                                   drd_stop_using_nonstack_mem);
    783 
    784    DRD_(clientreq_init)();
    785 
    786    DRD_(suppression_init)();
    787 
    788    DRD_(clientobj_init)();
    789 
    790    {
    791       Char* const smi = VG_(getenv)("DRD_SEGMENT_MERGING_INTERVAL");
    792       if (smi)
    793          DRD_(thread_set_segment_merge_interval)(VG_(strtoll10)(smi, NULL));
    794    }
    795 }
    796 
    797 
    798 VG_DETERMINE_INTERFACE_VERSION(drd_pre_clo_init)
    799