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ftmemsim-valgrind/drd/drd_thread.c
Bart Van Assche 9a196291ec Made DRD_(thread_set_pthreadid)() idempotent. 
git-svn-id: svn://svn.valgrind.org/valgrind/trunk@9590
2009-04-23 17:12:39 +00:00

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/* -*- mode: C; c-basic-offset: 3; -*- */
/*
This file is part of drd, a thread error detector.
Copyright (C) 2006-2009 Bart Van Assche <bart.vanassche@gmail.com>.
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307, USA.
The GNU General Public License is contained in the file COPYING.
*/
#include "drd_error.h"
#include "drd_barrier.h"
#include "drd_clientobj.h"
#include "drd_cond.h"
#include "drd_mutex.h"
#include "drd_segment.h"
#include "drd_semaphore.h"
#include "drd_suppression.h"
#include "drd_thread.h"
#include "pub_tool_vki.h"
#include "pub_tool_basics.h" // Addr, SizeT
#include "pub_tool_errormgr.h" // VG_(unique_error)()
#include "pub_tool_libcassert.h" // tl_assert()
#include "pub_tool_libcbase.h" // VG_(strlen)()
#include "pub_tool_libcprint.h" // VG_(printf)()
#include "pub_tool_libcproc.h" // VG_(getenv)()
#include "pub_tool_machine.h"
#include "pub_tool_mallocfree.h" // VG_(malloc)(), VG_(free)()
#include "pub_tool_options.h" // VG_(clo_backtrace_size)
#include "pub_tool_threadstate.h" // VG_(get_pthread_id)()
/* Local functions. */
static void thread_append_segment(const DrdThreadId tid, Segment* const sg);
static void thread_discard_segment(const DrdThreadId tid, Segment* const sg);
static void thread_compute_conflict_set(struct bitmap** conflict_set,
const DrdThreadId tid);
/* Local variables. */
static ULong s_context_switch_count;
static ULong s_discard_ordered_segments_count;
static ULong s_update_conflict_set_count;
static ULong s_conflict_set_new_segment_count;
static ULong s_conflict_set_combine_vc_count;
static ULong s_conflict_set_bitmap_creation_count;
static ULong s_conflict_set_bitmap2_creation_count;
static ThreadId s_vg_running_tid = VG_INVALID_THREADID;
DrdThreadId DRD_(g_drd_running_tid) = DRD_INVALID_THREADID;
ThreadInfo DRD_(g_threadinfo)[DRD_N_THREADS];
struct bitmap* DRD_(g_conflict_set);
static Bool s_trace_context_switches = False;
static Bool s_trace_conflict_set = False;
static Bool s_trace_fork_join = False;
static Bool s_segment_merging = True;
/* Function definitions. */
/** Enables/disables context switch tracing. */
void DRD_(thread_trace_context_switches)(const Bool t)
{
tl_assert(t == False || t == True);
s_trace_context_switches = t;
}
/** Enables/disables conflict set tracing. */
void DRD_(thread_trace_conflict_set)(const Bool t)
{
tl_assert(t == False || t == True);
s_trace_conflict_set = t;
}
/** Report whether fork/join tracing is enabled. */
Bool DRD_(thread_get_trace_fork_join)(void)
{
return s_trace_fork_join;
}
/** Enables/disables fork/join tracing. */
void DRD_(thread_set_trace_fork_join)(const Bool t)
{
tl_assert(t == False || t == True);
s_trace_fork_join = t;
}
/** Enables/disables segment merging. */
void DRD_(thread_set_segment_merging)(const Bool m)
{
tl_assert(m == False || m == True);
s_segment_merging = m;
}
/**
* Convert Valgrind's ThreadId into a DrdThreadId.
*
* @return DRD thread ID upon success and DRD_INVALID_THREADID if the passed
* Valgrind ThreadId does not yet exist.
*/
DrdThreadId DRD_(VgThreadIdToDrdThreadId)(const ThreadId tid)
{
int i;
if (tid == VG_INVALID_THREADID)
return DRD_INVALID_THREADID;
for (i = 1; i < DRD_N_THREADS; i++)
{
if (DRD_(g_threadinfo)[i].vg_thread_exists == True
&& DRD_(g_threadinfo)[i].vg_threadid == tid)
{
return i;
}
}
return DRD_INVALID_THREADID;
}
/** Allocate a new DRD thread ID for the specified Valgrind thread ID. */
static DrdThreadId DRD_(VgThreadIdToNewDrdThreadId)(const ThreadId tid)
{
int i;
tl_assert(DRD_(VgThreadIdToDrdThreadId)(tid) == DRD_INVALID_THREADID);
for (i = 1; i < DRD_N_THREADS; i++)
{
if (DRD_(g_threadinfo)[i].vg_thread_exists == False
&& DRD_(g_threadinfo)[i].posix_thread_exists == False
&& DRD_(g_threadinfo)[i].detached_posix_thread == False)
{
tl_assert(! DRD_(IsValidDrdThreadId)(i));
DRD_(g_threadinfo)[i].vg_thread_exists = True;
DRD_(g_threadinfo)[i].vg_threadid = tid;
DRD_(g_threadinfo)[i].pt_threadid = INVALID_POSIX_THREADID;
DRD_(g_threadinfo)[i].stack_min = 0;
DRD_(g_threadinfo)[i].stack_min_min = 0;
DRD_(g_threadinfo)[i].stack_startup = 0;
DRD_(g_threadinfo)[i].stack_max = 0;
DRD_(g_threadinfo)[i].is_recording = True;
DRD_(g_threadinfo)[i].synchr_nesting = 0;
tl_assert(DRD_(g_threadinfo)[i].first == 0);
tl_assert(DRD_(g_threadinfo)[i].last == 0);
tl_assert(DRD_(IsValidDrdThreadId)(i));
return i;
}
}
tl_assert(False);
return DRD_INVALID_THREADID;
}
/** Convert a POSIX thread ID into a DRD thread ID. */
DrdThreadId DRD_(PtThreadIdToDrdThreadId)(const PThreadId tid)
{
int i;
tl_assert(tid != INVALID_POSIX_THREADID);
for (i = 1; i < DRD_N_THREADS; i++)
{
if (DRD_(g_threadinfo)[i].posix_thread_exists
&& DRD_(g_threadinfo)[i].pt_threadid == tid)
{
return i;
}
}
return DRD_INVALID_THREADID;
}
/** Convert a DRD thread ID into a Valgrind thread ID. */
ThreadId DRD_(DrdThreadIdToVgThreadId)(const DrdThreadId tid)
{
tl_assert(0 <= (int)tid && tid < DRD_N_THREADS
&& tid != DRD_INVALID_THREADID);
return (DRD_(g_threadinfo)[tid].vg_thread_exists
? DRD_(g_threadinfo)[tid].vg_threadid
: VG_INVALID_THREADID);
}
#if 0
/**
* Sanity check of the doubly linked list of segments referenced by a
* ThreadInfo struct.
* @return True if sane, False if not.
*/
static Bool DRD_(sane_ThreadInfo)(const ThreadInfo* const ti)
{
Segment* p;
for (p = ti->first; p; p = p->next) {
if (p->next && p->next->prev != p)
return False;
if (p->next == 0 && p != ti->last)
return False;
}
for (p = ti->last; p; p = p->prev) {
if (p->prev && p->prev->next != p)
return False;
if (p->prev == 0 && p != ti->first)
return False;
}
return True;
}
#endif
/**
* Create the first segment for a newly started thread.
*
* This function is called from the handler installed via
* VG_(track_pre_thread_ll_create)(). The Valgrind core invokes this handler
* from the context of the creator thread, before the new thread has been
* created.
*
* @param[in] creator DRD thread ID of the creator thread.
* @param[in] vg_created Valgrind thread ID of the created thread.
*
* @return DRD thread ID of the created thread.
*/
DrdThreadId DRD_(thread_pre_create)(const DrdThreadId creator,
const ThreadId vg_created)
{
DrdThreadId created;
tl_assert(DRD_(VgThreadIdToDrdThreadId)(vg_created) == DRD_INVALID_THREADID);
created = DRD_(VgThreadIdToNewDrdThreadId)(vg_created);
tl_assert(0 <= (int)created && created < DRD_N_THREADS
&& created != DRD_INVALID_THREADID);
tl_assert(DRD_(g_threadinfo)[created].first == 0);
tl_assert(DRD_(g_threadinfo)[created].last == 0);
thread_append_segment(created, DRD_(sg_new)(creator, created));
return created;
}
/**
* Initialize DRD_(g_threadinfo)[] for a newly created thread. Must be called
* after the thread has been created and before any client instructions are run
* on the newly created thread, e.g. from the handler installed via
* VG_(track_pre_thread_first_insn)().
*
* @param[in] vg_created Valgrind thread ID of the newly created thread.
*
* @return DRD thread ID for the new thread.
*/
DrdThreadId DRD_(thread_post_create)(const ThreadId vg_created)
{
const DrdThreadId created = DRD_(VgThreadIdToDrdThreadId)(vg_created);
tl_assert(0 <= (int)created && created < DRD_N_THREADS
&& created != DRD_INVALID_THREADID);
DRD_(g_threadinfo)[created].stack_max
= VG_(thread_get_stack_max)(vg_created);
DRD_(g_threadinfo)[created].stack_startup
= DRD_(g_threadinfo)[created].stack_max;
DRD_(g_threadinfo)[created].stack_min
= DRD_(g_threadinfo)[created].stack_max;
DRD_(g_threadinfo)[created].stack_min_min
= DRD_(g_threadinfo)[created].stack_max;
DRD_(g_threadinfo)[created].stack_size
= VG_(thread_get_stack_size)(vg_created);
tl_assert(DRD_(g_threadinfo)[created].stack_max != 0);
return created;
}
/**
* Process VG_USERREQ__POST_THREAD_JOIN. This client request is invoked just
* after thread drd_joiner joined thread drd_joinee.
*/
void DRD_(thread_post_join)(DrdThreadId drd_joiner, DrdThreadId drd_joinee)
{
tl_assert(DRD_(IsValidDrdThreadId)(drd_joiner));
tl_assert(DRD_(IsValidDrdThreadId)(drd_joinee));
DRD_(thread_new_segment)(drd_joinee);
DRD_(thread_combine_vc)(drd_joiner, drd_joinee);
DRD_(thread_new_segment)(drd_joiner);
if (s_trace_fork_join)
{
const ThreadId joiner = DRD_(DrdThreadIdToVgThreadId)(drd_joiner);
const ThreadId joinee = DRD_(DrdThreadIdToVgThreadId)(drd_joinee);
const unsigned msg_size = 256;
char* msg;
msg = VG_(malloc)("drd.main.dptj.1", msg_size);
tl_assert(msg);
VG_(snprintf)(msg, msg_size,
"drd_post_thread_join joiner = %d/%d, joinee = %d/%d",
joiner, drd_joiner, joinee, drd_joinee);
if (joiner)
{
VG_(snprintf)(msg + VG_(strlen)(msg), msg_size - VG_(strlen)(msg),
", new vc: ");
DRD_(vc_snprint)(msg + VG_(strlen)(msg), msg_size - VG_(strlen)(msg),
DRD_(thread_get_vc)(drd_joiner));
}
VG_(message)(Vg_DebugMsg, "%s", msg);
VG_(free)(msg);
}
if (! DRD_(get_check_stack_accesses)())
{
DRD_(finish_suppression)(DRD_(thread_get_stack_max)(drd_joinee)
- DRD_(thread_get_stack_size)(drd_joinee),
DRD_(thread_get_stack_max)(drd_joinee));
}
DRD_(clientobj_delete_thread)(drd_joinee);
DRD_(thread_delete)(drd_joinee);
}
/**
* NPTL hack: NPTL allocates the 'struct pthread' on top of the stack,
* and accesses this data structure from multiple threads without locking.
* Any conflicting accesses in the range stack_startup..stack_max will be
* ignored.
*/
void DRD_(thread_set_stack_startup)(const DrdThreadId tid,
const Addr stack_startup)
{
tl_assert(0 <= (int)tid && tid < DRD_N_THREADS
&& tid != DRD_INVALID_THREADID);
tl_assert(DRD_(g_threadinfo)[tid].stack_min <= stack_startup);
tl_assert(stack_startup <= DRD_(g_threadinfo)[tid].stack_max);
DRD_(g_threadinfo)[tid].stack_startup = stack_startup;
}
/** Return the stack pointer for the specified thread. */
Addr DRD_(thread_get_stack_min)(const DrdThreadId tid)
{
tl_assert(0 <= (int)tid && tid < DRD_N_THREADS
&& tid != DRD_INVALID_THREADID);
return DRD_(g_threadinfo)[tid].stack_min;
}
/**
* Return the lowest value that was ever assigned to the stack pointer
* for the specified thread.
*/
Addr DRD_(thread_get_stack_min_min)(const DrdThreadId tid)
{
tl_assert(0 <= (int)tid && tid < DRD_N_THREADS
&& tid != DRD_INVALID_THREADID);
return DRD_(g_threadinfo)[tid].stack_min_min;
}
/** Return the top address for the stack of the specified thread. */
Addr DRD_(thread_get_stack_max)(const DrdThreadId tid)
{
tl_assert(0 <= (int)tid && tid < DRD_N_THREADS
&& tid != DRD_INVALID_THREADID);
return DRD_(g_threadinfo)[tid].stack_max;
}
/** Return the maximum stack size for the specified thread. */
SizeT DRD_(thread_get_stack_size)(const DrdThreadId tid)
{
tl_assert(0 <= (int)tid && tid < DRD_N_THREADS
&& tid != DRD_INVALID_THREADID);
return DRD_(g_threadinfo)[tid].stack_size;
}
/**
* Clean up thread-specific data structures. Call this just after
* pthread_join().
*/
void DRD_(thread_delete)(const DrdThreadId tid)
{
Segment* sg;
Segment* sg_prev;
tl_assert(DRD_(IsValidDrdThreadId)(tid));
tl_assert(DRD_(g_threadinfo)[tid].synchr_nesting >= 0);
for (sg = DRD_(g_threadinfo)[tid].last; sg; sg = sg_prev)
{
sg_prev = sg->prev;
sg->prev = 0;
sg->next = 0;
DRD_(sg_put)(sg);
}
DRD_(g_threadinfo)[tid].vg_thread_exists = False;
DRD_(g_threadinfo)[tid].posix_thread_exists = False;
tl_assert(DRD_(g_threadinfo)[tid].detached_posix_thread == False);
DRD_(g_threadinfo)[tid].first = 0;
DRD_(g_threadinfo)[tid].last = 0;
tl_assert(! DRD_(IsValidDrdThreadId)(tid));
}
/**
* Called after a thread performed its last memory access and before
* thread_delete() is called. Note: thread_delete() is only called for
* joinable threads, not for detached threads.
*/
void DRD_(thread_finished)(const DrdThreadId tid)
{
tl_assert(0 <= (int)tid && tid < DRD_N_THREADS
&& tid != DRD_INVALID_THREADID);
DRD_(g_threadinfo)[tid].vg_thread_exists = False;
if (DRD_(g_threadinfo)[tid].detached_posix_thread)
{
/*
* Once a detached thread has finished, its stack is deallocated and
* should no longer be taken into account when computing the conflict set.
*/
DRD_(g_threadinfo)[tid].stack_min = DRD_(g_threadinfo)[tid].stack_max;
/*
* For a detached thread, calling pthread_exit() invalidates the
* POSIX thread ID associated with the detached thread. For joinable
* POSIX threads however, the POSIX thread ID remains live after the
* pthread_exit() call until pthread_join() is called.
*/
DRD_(g_threadinfo)[tid].posix_thread_exists = False;
}
}
/** Called just before pthread_cancel(). */
void DRD_(thread_pre_cancel)(const DrdThreadId tid)
{
tl_assert(0 <= (int)tid && tid < DRD_N_THREADS
&& tid != DRD_INVALID_THREADID);
tl_assert(DRD_(g_threadinfo)[tid].pt_threadid != INVALID_POSIX_THREADID);
DRD_(g_threadinfo)[tid].synchr_nesting = 0;
}
/**
* Store the POSIX thread ID for the specified thread.
*
* @note This function can be called two times for the same thread -- see also
* the comment block preceding the pthread_create() wrapper in
* drd_pthread_intercepts.c.
*/
void DRD_(thread_set_pthreadid)(const DrdThreadId tid, const PThreadId ptid)
{
tl_assert(0 <= (int)tid && tid < DRD_N_THREADS
&& tid != DRD_INVALID_THREADID);
tl_assert(DRD_(g_threadinfo)[tid].pt_threadid == INVALID_POSIX_THREADID
|| DRD_(g_threadinfo)[tid].pt_threadid == ptid);
tl_assert(ptid != INVALID_POSIX_THREADID);
DRD_(g_threadinfo)[tid].posix_thread_exists = True;
DRD_(g_threadinfo)[tid].pt_threadid = ptid;
}
/** Returns true for joinable threads and false for detached threads. */
Bool DRD_(thread_get_joinable)(const DrdThreadId tid)
{
tl_assert(0 <= (int)tid && tid < DRD_N_THREADS
&& tid != DRD_INVALID_THREADID);
return ! DRD_(g_threadinfo)[tid].detached_posix_thread;
}
/** Store the thread mode: joinable or detached. */
void DRD_(thread_set_joinable)(const DrdThreadId tid, const Bool joinable)
{
tl_assert(0 <= (int)tid && tid < DRD_N_THREADS
&& tid != DRD_INVALID_THREADID);
tl_assert(!! joinable == joinable);
tl_assert(DRD_(g_threadinfo)[tid].pt_threadid != INVALID_POSIX_THREADID);
#if 0
VG_(message)(Vg_DebugMsg,
"thread_set_joinable(%d/%d, %s)",
tid,
DRD_(g_threadinfo)[tid].vg_threadid,
joinable ? "joinable" : "detached");
#endif
DRD_(g_threadinfo)[tid].detached_posix_thread = ! joinable;
}
/**
* Update s_vg_running_tid, DRD_(g_drd_running_tid) and recalculate the
* conflict set.
*/
void DRD_(thread_set_vg_running_tid)(const ThreadId vg_tid)
{
tl_assert(vg_tid != VG_INVALID_THREADID);
if (vg_tid != s_vg_running_tid)
{
DRD_(thread_set_running_tid)(vg_tid,
DRD_(VgThreadIdToDrdThreadId)(vg_tid));
}
tl_assert(s_vg_running_tid != VG_INVALID_THREADID);
tl_assert(DRD_(g_drd_running_tid) != DRD_INVALID_THREADID);
}
/**
* Update s_vg_running_tid, DRD_(g_drd_running_tid) and recalculate the
* conflict set.
*/
void DRD_(thread_set_running_tid)(const ThreadId vg_tid,
const DrdThreadId drd_tid)
{
tl_assert(vg_tid != VG_INVALID_THREADID);
tl_assert(drd_tid != DRD_INVALID_THREADID);
if (vg_tid != s_vg_running_tid)
{
if (s_trace_context_switches
&& DRD_(g_drd_running_tid) != DRD_INVALID_THREADID)
{
VG_(message)(Vg_DebugMsg,
"Context switch from thread %d/%d to thread %d/%d;"
" segments: %llu",
s_vg_running_tid, DRD_(g_drd_running_tid),
DRD_(DrdThreadIdToVgThreadId)(drd_tid), drd_tid,
DRD_(sg_get_segments_alive_count)());
}
s_vg_running_tid = vg_tid;
DRD_(g_drd_running_tid) = drd_tid;
thread_compute_conflict_set(&DRD_(g_conflict_set), drd_tid);
s_context_switch_count++;
}
tl_assert(s_vg_running_tid != VG_INVALID_THREADID);
tl_assert(DRD_(g_drd_running_tid) != DRD_INVALID_THREADID);
}
/**
* Increase the synchronization nesting counter. Must be called before the
* client calls a synchronization function.
*/
int DRD_(thread_enter_synchr)(const DrdThreadId tid)
{
tl_assert(DRD_(IsValidDrdThreadId)(tid));
return DRD_(g_threadinfo)[tid].synchr_nesting++;
}
/**
* Decrease the synchronization nesting counter. Must be called after the
* client left a synchronization function.
*/
int DRD_(thread_leave_synchr)(const DrdThreadId tid)
{
tl_assert(DRD_(IsValidDrdThreadId)(tid));
tl_assert(DRD_(g_threadinfo)[tid].synchr_nesting >= 1);
return --DRD_(g_threadinfo)[tid].synchr_nesting;
}
/** Returns the synchronization nesting counter. */
int DRD_(thread_get_synchr_nesting_count)(const DrdThreadId tid)
{
tl_assert(DRD_(IsValidDrdThreadId)(tid));
return DRD_(g_threadinfo)[tid].synchr_nesting;
}
/** Append a new segment at the end of the segment list. */
static
void thread_append_segment(const DrdThreadId tid, Segment* const sg)
{
tl_assert(0 <= (int)tid && tid < DRD_N_THREADS
&& tid != DRD_INVALID_THREADID);
// tl_assert(DRD_(sane_ThreadInfo)(&DRD_(g_threadinfo)[tid]));
sg->prev = DRD_(g_threadinfo)[tid].last;
sg->next = 0;
if (DRD_(g_threadinfo)[tid].last)
DRD_(g_threadinfo)[tid].last->next = sg;
DRD_(g_threadinfo)[tid].last = sg;
if (DRD_(g_threadinfo)[tid].first == 0)
DRD_(g_threadinfo)[tid].first = sg;
// tl_assert(DRD_(sane_ThreadInfo)(&DRD_(g_threadinfo)[tid]));
}
/**
* Remove a segment from the segment list of thread threadid, and free the
* associated memory.
*/
static
void thread_discard_segment(const DrdThreadId tid, Segment* const sg)
{
tl_assert(0 <= (int)tid && tid < DRD_N_THREADS
&& tid != DRD_INVALID_THREADID);
//tl_assert(DRD_(sane_ThreadInfo)(&DRD_(g_threadinfo)[tid]));
if (sg->prev)
sg->prev->next = sg->next;
if (sg->next)
sg->next->prev = sg->prev;
if (sg == DRD_(g_threadinfo)[tid].first)
DRD_(g_threadinfo)[tid].first = sg->next;
if (sg == DRD_(g_threadinfo)[tid].last)
DRD_(g_threadinfo)[tid].last = sg->prev;
DRD_(sg_put)(sg);
//tl_assert(DRD_(sane_ThreadInfo)(&DRD_(g_threadinfo)[tid]));
}
/**
* Returns a pointer to the vector clock of the most recent segment associated
* with thread 'tid'.
*/
VectorClock* DRD_(thread_get_vc)(const DrdThreadId tid)
{
tl_assert(0 <= (int)tid && tid < DRD_N_THREADS
&& tid != DRD_INVALID_THREADID);
tl_assert(DRD_(g_threadinfo)[tid].last);
return &DRD_(g_threadinfo)[tid].last->vc;
}
/**
* Return the latest segment of thread 'tid' and increment its reference count.
*/
void DRD_(thread_get_latest_segment)(Segment** sg, const DrdThreadId tid)
{
tl_assert(sg);
tl_assert(0 <= (int)tid && tid < DRD_N_THREADS
&& tid != DRD_INVALID_THREADID);
tl_assert(DRD_(g_threadinfo)[tid].last);
DRD_(sg_put)(*sg);
*sg = DRD_(sg_get)(DRD_(g_threadinfo)[tid].last);
}
/**
* Compute the minimum of all latest vector clocks of all threads
* (Michiel Ronsse calls this "clock snooping" in his papers about DIOTA).
*
* @param vc pointer to a vectorclock, holds result upon return.
*/
static void DRD_(thread_compute_minimum_vc)(VectorClock* vc)
{
unsigned i;
Bool first;
Segment* latest_sg;
first = True;
for (i = 0; i < sizeof(DRD_(g_threadinfo)) / sizeof(DRD_(g_threadinfo)[0]);
i++)
{
latest_sg = DRD_(g_threadinfo)[i].last;
if (latest_sg)
{
if (first)
DRD_(vc_assign)(vc, &latest_sg->vc);
else
DRD_(vc_min)(vc, &latest_sg->vc);
first = False;
}
}
}
/**
* Compute the maximum of all latest vector clocks of all threads.
*
* @param vc pointer to a vectorclock, holds result upon return.
*/
static void DRD_(thread_compute_maximum_vc)(VectorClock* vc)
{
unsigned i;
Bool first;
Segment* latest_sg;
first = True;
for (i = 0; i < sizeof(DRD_(g_threadinfo)) / sizeof(DRD_(g_threadinfo)[0]);
i++)
{
latest_sg = DRD_(g_threadinfo)[i].last;
if (latest_sg)
{
if (first)
DRD_(vc_assign)(vc, &latest_sg->vc);
else
DRD_(vc_combine)(vc, &latest_sg->vc);
first = False;
}
}
}
/**
* Discard all segments that have a defined order against the latest vector
* clock of all threads -- these segments can no longer be involved in a
* data race.
*/
static void DRD_(thread_discard_ordered_segments)(void)
{
unsigned i;
VectorClock thread_vc_min;
s_discard_ordered_segments_count++;
DRD_(vc_init)(&thread_vc_min, 0, 0);
DRD_(thread_compute_minimum_vc)(&thread_vc_min);
if (DRD_(sg_get_trace)())
{
char msg[256];
VectorClock thread_vc_max;
DRD_(vc_init)(&thread_vc_max, 0, 0);
DRD_(thread_compute_maximum_vc)(&thread_vc_max);
VG_(snprintf)(msg, sizeof(msg),
"Discarding ordered segments -- min vc is ");
DRD_(vc_snprint)(msg + VG_(strlen)(msg), sizeof(msg) - VG_(strlen)(msg),
&thread_vc_min);
VG_(snprintf)(msg + VG_(strlen)(msg), sizeof(msg) - VG_(strlen)(msg),
", max vc is ");
DRD_(vc_snprint)(msg + VG_(strlen)(msg), sizeof(msg) - VG_(strlen)(msg),
&thread_vc_max);
VG_(message)(Vg_UserMsg, "%s", msg);
DRD_(vc_cleanup)(&thread_vc_max);
}
for (i = 0; i < sizeof(DRD_(g_threadinfo)) / sizeof(DRD_(g_threadinfo)[0]);
i++)
{
Segment* sg;
Segment* sg_next;
for (sg = DRD_(g_threadinfo)[i].first;
sg && (sg_next = sg->next) && DRD_(vc_lte)(&sg->vc, &thread_vc_min);
sg = sg_next)
{
thread_discard_segment(i, sg);
}
}
DRD_(vc_cleanup)(&thread_vc_min);
}
/**
* Merge all segments that may be merged without triggering false positives
* or discarding real data races. For the theoretical background of segment
* merging, see also the following paper:
* Mark Christiaens, Michiel Ronsse and Koen De Bosschere.
* Bounding the number of segment histories during data race detection.
* Parallel Computing archive, Volume 28, Issue 9, pp 1221-1238,
* September 2002.
*/
static void thread_merge_segments(void)
{
unsigned i;
for (i = 0; i < sizeof(DRD_(g_threadinfo)) / sizeof(DRD_(g_threadinfo)[0]);
i++)
{
Segment* sg;
// tl_assert(DRD_(sane_ThreadInfo)(&DRD_(g_threadinfo)[i]));
for (sg = DRD_(g_threadinfo)[i].first; sg; sg = sg->next)
{
if (DRD_(sg_get_refcnt)(sg) == 1
&& sg->next
&& DRD_(sg_get_refcnt)(sg->next) == 1
&& sg->next->next)
{
/* Merge sg and sg->next into sg. */
DRD_(sg_merge)(sg, sg->next);
thread_discard_segment(i, sg->next);
}
}
// tl_assert(DRD_(sane_ThreadInfo)(&DRD_(g_threadinfo)[i]));
}
}
/**
* Create a new segment for the specified thread, and discard any segments
* that cannot cause races anymore.
*/
void DRD_(thread_new_segment)(const DrdThreadId tid)
{
Segment* new_sg;
tl_assert(0 <= (int)tid && tid < DRD_N_THREADS
&& tid != DRD_INVALID_THREADID);
new_sg = DRD_(sg_new)(tid, tid);
thread_append_segment(tid, new_sg);
thread_compute_conflict_set(&DRD_(g_conflict_set), DRD_(g_drd_running_tid));
s_conflict_set_new_segment_count++;
DRD_(thread_discard_ordered_segments)();
if (s_segment_merging)
{
thread_merge_segments();
}
}
/** Call this function after thread 'joiner' joined thread 'joinee'. */
void DRD_(thread_combine_vc)(DrdThreadId joiner, DrdThreadId joinee)
{
tl_assert(joiner != joinee);
tl_assert(0 <= (int)joiner && joiner < DRD_N_THREADS
&& joiner != DRD_INVALID_THREADID);
tl_assert(0 <= (int)joinee && joinee < DRD_N_THREADS
&& joinee != DRD_INVALID_THREADID);
tl_assert(DRD_(g_threadinfo)[joiner].last);
tl_assert(DRD_(g_threadinfo)[joinee].last);
DRD_(vc_combine)(&DRD_(g_threadinfo)[joiner].last->vc,
&DRD_(g_threadinfo)[joinee].last->vc);
DRD_(thread_discard_ordered_segments)();
if (joiner == DRD_(g_drd_running_tid))
{
thread_compute_conflict_set(&DRD_(g_conflict_set), joiner);
}
}
/**
* Call this function after thread 'tid' had to wait because of thread
* synchronization until the memory accesses in the segment with vector clock
* 'vc' finished.
*/
void DRD_(thread_combine_vc2)(DrdThreadId tid, const VectorClock* const vc)
{
tl_assert(0 <= (int)tid && tid < DRD_N_THREADS
&& tid != DRD_INVALID_THREADID);
tl_assert(DRD_(g_threadinfo)[tid].last);
tl_assert(vc);
DRD_(vc_combine)(&DRD_(g_threadinfo)[tid].last->vc, vc);
thread_compute_conflict_set(&DRD_(g_conflict_set), tid);
DRD_(thread_discard_ordered_segments)();
s_conflict_set_combine_vc_count++;
}
/**
* Call this function whenever a thread is no longer using the memory
* [ a1, a2 [, e.g. because of a call to free() or a stack pointer
* increase.
*/
void DRD_(thread_stop_using_mem)(const Addr a1, const Addr a2)
{
DrdThreadId other_user;
unsigned i;
/* For all threads, mark the range [ a1, a2 [ as no longer in use. */
other_user = DRD_INVALID_THREADID;
for (i = 0; i < sizeof(DRD_(g_threadinfo)) / sizeof(DRD_(g_threadinfo)[0]);
i++)
{
Segment* p;
for (p = DRD_(g_threadinfo)[i].first; p; p = p->next)
{
if (other_user == DRD_INVALID_THREADID
&& i != DRD_(g_drd_running_tid))
{
if (UNLIKELY(DRD_(bm_test_and_clear)(p->bm, a1, a2)))
{
other_user = i;
}
continue;
}
DRD_(bm_clear)(p->bm, a1, a2);
}
}
/*
* If any other thread had accessed memory in [ a1, a2 [, update the
* conflict set.
*/
if (other_user != DRD_INVALID_THREADID
&& DRD_(bm_has_any_access)(DRD_(g_conflict_set), a1, a2))
{
thread_compute_conflict_set(&DRD_(g_conflict_set),
DRD_(thread_get_running_tid)());
}
}
/** Start recording memory access information. */
void DRD_(thread_start_recording)(const DrdThreadId tid)
{
tl_assert(0 <= (int)tid && tid < DRD_N_THREADS
&& tid != DRD_INVALID_THREADID);
tl_assert(! DRD_(g_threadinfo)[tid].is_recording);
DRD_(g_threadinfo)[tid].is_recording = True;
}
/** Stop recording memory access information. */
void DRD_(thread_stop_recording)(const DrdThreadId tid)
{
tl_assert(0 <= (int)tid && tid < DRD_N_THREADS
&& tid != DRD_INVALID_THREADID);
tl_assert(DRD_(g_threadinfo)[tid].is_recording);
DRD_(g_threadinfo)[tid].is_recording = False;
}
/**
* Print the segment information for all threads.
*
* This function is only used for debugging purposes.
*/
void DRD_(thread_print_all)(void)
{
unsigned i;
Segment* p;
for (i = 0; i < sizeof(DRD_(g_threadinfo)) / sizeof(DRD_(g_threadinfo)[0]);
i++)
{
if (DRD_(g_threadinfo)[i].first)
{
VG_(printf)("**************\n"
"* thread %3d (%d/%d/%d/0x%lx/%d) *\n"
"**************\n",
i,
DRD_(g_threadinfo)[i].vg_thread_exists,
DRD_(g_threadinfo)[i].vg_threadid,
DRD_(g_threadinfo)[i].posix_thread_exists,
DRD_(g_threadinfo)[i].pt_threadid,
DRD_(g_threadinfo)[i].detached_posix_thread);
for (p = DRD_(g_threadinfo)[i].first; p; p = p->next)
{
DRD_(sg_print)(p);
}
}
}
}
/** Show a call stack involved in a data race. */
static void show_call_stack(const DrdThreadId tid,
const Char* const msg,
ExeContext* const callstack)
{
const ThreadId vg_tid = DRD_(DrdThreadIdToVgThreadId)(tid);
VG_(message)(Vg_UserMsg, "%s (thread %d/%d)", msg, vg_tid, tid);
if (vg_tid != VG_INVALID_THREADID)
{
if (callstack)
{
VG_(pp_ExeContext)(callstack);
}
else
{
VG_(get_and_pp_StackTrace)(vg_tid, VG_(clo_backtrace_size));
}
}
else
{
VG_(message)(Vg_UserMsg,
" (thread finished, call stack no longer available)");
}
}
/** Print information about the segments involved in a data race. */
static void
thread_report_conflicting_segments_segment(const DrdThreadId tid,
const Addr addr,
const SizeT size,
const BmAccessTypeT access_type,
const Segment* const p)
{
unsigned i;
tl_assert(0 <= (int)tid && tid < DRD_N_THREADS
&& tid != DRD_INVALID_THREADID);
tl_assert(p);
for (i = 0; i < sizeof(DRD_(g_threadinfo)) / sizeof(DRD_(g_threadinfo)[0]);
i++)
{
if (i != tid)
{
Segment* q;
for (q = DRD_(g_threadinfo)[i].last; q; q = q->prev)
{
/*
* Since q iterates over the segments of thread i in order of
* decreasing vector clocks, if q->vc <= p->vc, then
* q->next->vc <= p->vc will also hold. Hence, break out of the
* loop once this condition is met.
*/
if (DRD_(vc_lte)(&q->vc, &p->vc))
break;
if (! DRD_(vc_lte)(&p->vc, &q->vc))
{
if (DRD_(bm_has_conflict_with)(q->bm, addr, addr + size,
access_type))
{
tl_assert(q->stacktrace);
show_call_stack(i, "Other segment start",
q->stacktrace);
show_call_stack(i, "Other segment end",
q->next ? q->next->stacktrace : 0);
}
}
}
}
}
}
/** Print information about all segments involved in a data race. */
void DRD_(thread_report_conflicting_segments)(const DrdThreadId tid,
const Addr addr,
const SizeT size,
const BmAccessTypeT access_type)
{
Segment* p;
tl_assert(0 <= (int)tid && tid < DRD_N_THREADS
&& tid != DRD_INVALID_THREADID);
for (p = DRD_(g_threadinfo)[tid].first; p; p = p->next)
{
if (DRD_(bm_has)(p->bm, addr, addr + size, access_type))
{
thread_report_conflicting_segments_segment(tid, addr, size,
access_type, p);
}
}
}
/**
* Compute a bitmap that represents the union of all memory accesses of all
* segments that are unordered to the current segment of the thread tid.
*/
static void thread_compute_conflict_set(struct bitmap** conflict_set,
const DrdThreadId tid)
{
Segment* p;
tl_assert(0 <= (int)tid && tid < DRD_N_THREADS
&& tid != DRD_INVALID_THREADID);
tl_assert(tid == DRD_(g_drd_running_tid));
s_update_conflict_set_count++;
s_conflict_set_bitmap_creation_count
-= DRD_(bm_get_bitmap_creation_count)();
s_conflict_set_bitmap2_creation_count
-= DRD_(bm_get_bitmap2_creation_count)();
if (*conflict_set)
{
DRD_(bm_delete)(*conflict_set);
}
*conflict_set = DRD_(bm_new)();
if (s_trace_conflict_set)
{
char msg[256];
VG_(snprintf)(msg, sizeof(msg),
"computing conflict set for thread %d/%d with vc ",
DRD_(DrdThreadIdToVgThreadId)(tid), tid);
DRD_(vc_snprint)(msg + VG_(strlen)(msg),
sizeof(msg) - VG_(strlen)(msg),
&DRD_(g_threadinfo)[tid].last->vc);
VG_(message)(Vg_UserMsg, "%s", msg);
}
p = DRD_(g_threadinfo)[tid].last;
{
unsigned j;
if (s_trace_conflict_set)
{
char msg[256];
VG_(snprintf)(msg, sizeof(msg),
"conflict set: thread [%d] at vc ",
tid);
DRD_(vc_snprint)(msg + VG_(strlen)(msg),
sizeof(msg) - VG_(strlen)(msg),
&p->vc);
VG_(message)(Vg_UserMsg, "%s", msg);
}
for (j = 0;
j < sizeof(DRD_(g_threadinfo)) / sizeof(DRD_(g_threadinfo)[0]);
j++)
{
if (j != tid && DRD_(IsValidDrdThreadId)(j))
{
const Segment* q;
for (q = DRD_(g_threadinfo)[j].last; q; q = q->prev)
{
if (! DRD_(vc_lte)(&q->vc, &p->vc)
&& ! DRD_(vc_lte)(&p->vc, &q->vc))
{
if (s_trace_conflict_set)
{
char msg[256];
VG_(snprintf)(msg, sizeof(msg),
"conflict set: [%d] merging segment ", j);
DRD_(vc_snprint)(msg + VG_(strlen)(msg),
sizeof(msg) - VG_(strlen)(msg),
&q->vc);
VG_(message)(Vg_UserMsg, "%s", msg);
}
DRD_(bm_merge2)(*conflict_set, q->bm);
}
else
{
if (s_trace_conflict_set)
{
char msg[256];
VG_(snprintf)(msg, sizeof(msg),
"conflict set: [%d] ignoring segment ", j);
DRD_(vc_snprint)(msg + VG_(strlen)(msg),
sizeof(msg) - VG_(strlen)(msg),
&q->vc);
VG_(message)(Vg_UserMsg, "%s", msg);
}
}
}
}
}
}
s_conflict_set_bitmap_creation_count
+= DRD_(bm_get_bitmap_creation_count)();
s_conflict_set_bitmap2_creation_count
+= DRD_(bm_get_bitmap2_creation_count)();
if (0 && s_trace_conflict_set)
{
VG_(message)(Vg_UserMsg, "[%d] new conflict set:", tid);
DRD_(bm_print)(*conflict_set);
VG_(message)(Vg_UserMsg, "[%d] end of new conflict set.", tid);
}
}
/** Report the number of context switches performed. */
ULong DRD_(thread_get_context_switch_count)(void)
{
return s_context_switch_count;
}
/** Report the number of ordered segments that have been discarded. */
ULong DRD_(thread_get_discard_ordered_segments_count)(void)
{
return s_discard_ordered_segments_count;
}
/** Return how many times the conflict set has been updated. */
ULong DRD_(thread_get_update_conflict_set_count)(ULong* dsnsc, ULong* dscvc)
{
tl_assert(dsnsc);
tl_assert(dscvc);
*dsnsc = s_conflict_set_new_segment_count;
*dscvc = s_conflict_set_combine_vc_count;
return s_update_conflict_set_count;
}
/**
* Return the number of first-level bitmaps that have been created during
* conflict set updates.
*/
ULong DRD_(thread_get_conflict_set_bitmap_creation_count)(void)
{
return s_conflict_set_bitmap_creation_count;
}
/**
* Return the number of second-level bitmaps that have been created during
* conflict set updates.
*/
ULong DRD_(thread_get_conflict_set_bitmap2_creation_count)(void)
{
return s_conflict_set_bitmap2_creation_count;
}
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