/*
This file is part of drd, a thread error detector.
Copyright (C) 2006-2012 Bart Van Assche <bvanassche@acm.org>.
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_barrier.h"
#include "drd_clientobj.h"
#include "drd_error.h"
#include "drd_suppression.h"
#include "pub_tool_errormgr.h" // VG_(maybe_record_error)()
#include "pub_tool_libcassert.h" // tl_assert()
#include "pub_tool_libcprint.h" // VG_(printf)()
#include "pub_tool_machine.h" // VG_(get_IP)()
#include "pub_tool_mallocfree.h" // VG_(malloc)(), VG_(free)()
#include "pub_tool_oset.h"
#include "pub_tool_threadstate.h" // VG_(get_running_tid)()
/* Type definitions. */
/** Information associated with one thread participating in a barrier. */
struct barrier_thread_info
{
UWord tid; // A DrdThreadId declared as UWord because
// this member variable is the key of an OSet.
Segment* sg; // Segment of the last pthread_barrier() call
// by thread tid.
Segment* post_wait_sg; // Segment created after *_barrier_wait() finished
ExeContext* wait_call_ctxt;// call stack for *_barrier_wait() call.
Bool thread_finished;// Whether thread 'tid' has finished.
};
/* Local functions. */
static void barrier_cleanup(struct barrier_info* p);
static void barrier_delete_thread(struct barrier_info* const p,
const DrdThreadId tid);
static const char* barrier_get_typename(struct barrier_info* const p);
static const char* barrier_type_name(const BarrierT bt);
static
void barrier_report_wait_delete_race(const struct barrier_info* const p,
const struct barrier_thread_info* const q);
/* Local variables. */
static Bool s_trace_barrier = False;
static ULong s_barrier_segment_creation_count;
/* Function definitions. */
void DRD_(barrier_set_trace)(const Bool trace_barrier)
{
s_trace_barrier = trace_barrier;
}
/**
* Initialize the structure *p with the specified thread ID and iteration
* information.
*/
static
void DRD_(barrier_thread_initialize)(struct barrier_thread_info* const p,
const DrdThreadId tid)
{
p->tid = tid;
p->sg = NULL;
p->post_wait_sg = 0;
p->wait_call_ctxt = 0;
p->thread_finished = False;
}
/**
* Deallocate the memory that is owned by members of
* struct barrier_thread_info.
*/
static void DRD_(barrier_thread_destroy)(struct barrier_thread_info* const p)
{
tl_assert(p);
DRD_(sg_put)(p->sg);
DRD_(sg_put)(p->post_wait_sg);
}
/**
* Initialize the structure *p with the specified client-side barrier address,
* barrier object size and number of participants in each barrier.
*/
static
void DRD_(barrier_initialize)(struct barrier_info* const p,
const Addr barrier,
const BarrierT barrier_type,
const Word count)
{
int i;
tl_assert(barrier != 0);
tl_assert(barrier_type == pthread_barrier || barrier_type == gomp_barrier);
tl_assert(p->a1 == barrier);
p->cleanup = (void(*)(DrdClientobj*))barrier_cleanup;
p->delete_thread
= (void(*)(DrdClientobj*, DrdThreadId))barrier_delete_thread;
p->barrier_type = barrier_type;
p->count = count;
p->pre_iteration = 0;
p->post_iteration = 0;
p->pre_waiters_left = count;
p->post_waiters_left = count;
tl_assert(sizeof(((struct barrier_thread_info*)0)->tid) == sizeof(Word));
tl_assert(sizeof(((struct barrier_thread_info*)0)->tid)
>= sizeof(DrdThreadId));
for (i = 0; i < 2; i++) {
p->oset[i] = VG_(OSetGen_Create)(0, 0, VG_(malloc), "drd.barrier.bi.1",
VG_(free));
}
}
/**
* Deallocate the memory owned by the struct barrier_info object and also
* all the nodes in the OSet p->oset.
*
* Called by clientobj_destroy().
*/
static void barrier_cleanup(struct barrier_info* p)
{
struct barrier_thread_info* q;
Segment* latest_sg = 0;
OSet* oset;
int i;
tl_assert(p);
DRD_(thread_get_latest_segment)(&latest_sg, DRD_(thread_get_running_tid)());
tl_assert(latest_sg);
if (p->pre_waiters_left != p->count) {
BarrierErrInfo bei = { DRD_(thread_get_running_tid)(), p->a1, 0, 0 };
VG_(maybe_record_error)(VG_(get_running_tid)(),
BarrierErr,
VG_(get_IP)(VG_(get_running_tid)()),
"Destruction of barrier that is being waited"
" upon",
&bei);
} else {
oset = p->oset[1 - (p->pre_iteration & 1)];
VG_(OSetGen_ResetIter)(oset);
for ( ; (q = VG_(OSetGen_Next)(oset)) != 0; ) {
if (q->post_wait_sg && !DRD_(vc_lte)(&q->post_wait_sg->vc,
&latest_sg->vc))
{
barrier_report_wait_delete_race(p, q);
}
DRD_(barrier_thread_destroy)(q);
}
}
for (i = 0; i < 2; i++) {
VG_(OSetGen_Destroy)(p->oset[i]);
p->oset[i] = NULL;
}
DRD_(sg_put)(latest_sg);
}
/**
* Look up the client-side barrier address barrier in s_barrier[]. If not
* found, add it.
*/
static
struct barrier_info*
DRD_(barrier_get_or_allocate)(const Addr barrier,
const BarrierT barrier_type, const Word count)
{
struct barrier_info *p;
tl_assert(barrier_type == pthread_barrier || barrier_type == gomp_barrier);
tl_assert(offsetof(DrdClientobj, barrier) == 0);
p = &(DRD_(clientobj_get)(barrier, ClientBarrier)->barrier);
if (p == 0)
{
p = &(DRD_(clientobj_add)(barrier, ClientBarrier)->barrier);
DRD_(barrier_initialize)(p, barrier, barrier_type, count);
}
return p;
}
/**
* Look up the address of the struct barrier_info associated with the
* client-side barrier object.
*/
static struct barrier_info* DRD_(barrier_get)(const Addr barrier)
{
tl_assert(offsetof(DrdClientobj, barrier) == 0);
return &(DRD_(clientobj_get)(barrier, ClientBarrier)->barrier);
}
/**
* Initialize a barrier with given client address, barrier type and number of
* participants. The 'reinitialization' argument indicates whether a barrier
* object is being initialized or reinitialized.
*
* Called before pthread_barrier_init().
*/
void DRD_(barrier_init)(const Addr barrier,
const BarrierT barrier_type, const Word count,
const Bool reinitialization)
{
struct barrier_info* p;
tl_assert(barrier_type == pthread_barrier || barrier_type == gomp_barrier);
if (count == 0)
{
BarrierErrInfo bei = { DRD_(thread_get_running_tid)(), barrier, 0, 0 };
VG_(maybe_record_error)(VG_(get_running_tid)(),
BarrierErr,
VG_(get_IP)(VG_(get_running_tid)()),
"pthread_barrier_init: 'count' argument is zero",
&bei);
}
if (! reinitialization && barrier_type == pthread_barrier)
{
p = DRD_(barrier_get)(barrier);
if (p)
{
BarrierErrInfo bei = { DRD_(thread_get_running_tid)(), barrier, 0, 0 };
VG_(maybe_record_error)(VG_(get_running_tid)(),
BarrierErr,
VG_(get_IP)(VG_(get_running_tid)()),
"Barrier reinitialization",
&bei);
}
}
p = DRD_(barrier_get_or_allocate)(barrier, barrier_type, count);
if (s_trace_barrier) {
if (reinitialization)
DRD_(trace_msg)("[%d] barrier_reinit %s 0x%lx count %ld -> %ld",
DRD_(thread_get_running_tid)(),
barrier_get_typename(p), barrier, p->count, count);
else
DRD_(trace_msg)("[%d] barrier_init %s 0x%lx",
DRD_(thread_get_running_tid)(),
barrier_get_typename(p),
barrier);
}
if (reinitialization && p->count != count)
{
if (p->pre_waiters_left != p->count || p->post_waiters_left != p->count)
{
BarrierErrInfo bei = { DRD_(thread_get_running_tid)(), p->a1, 0, 0 };
VG_(maybe_record_error)(VG_(get_running_tid)(),
BarrierErr,
VG_(get_IP)(VG_(get_running_tid)()),
"Reinitialization of barrier with active"
" waiters",
&bei);
}
p->count = count;
}
}
/** Called after pthread_barrier_destroy() / gomp_barrier_destroy(). */
void DRD_(barrier_destroy)(const Addr barrier, const BarrierT barrier_type)
{
struct barrier_info* p;
p = DRD_(barrier_get)(barrier);
if (s_trace_barrier)
DRD_(trace_msg)("[%d] barrier_destroy %s 0x%lx",
DRD_(thread_get_running_tid)(),
barrier_get_typename(p), barrier);
if (p == 0)
{
GenericErrInfo GEI = {
.tid = DRD_(thread_get_running_tid)(),
.addr = barrier,
};
VG_(maybe_record_error)(VG_(get_running_tid)(),
GenericErr,
VG_(get_IP)(VG_(get_running_tid)()),
"Not a barrier",
&GEI);
return;
}
if (p->pre_waiters_left != p->count || p->post_waiters_left != p->count)
{
BarrierErrInfo bei = { DRD_(thread_get_running_tid)(), p->a1, 0, 0 };
VG_(maybe_record_error)(VG_(get_running_tid)(),
BarrierErr,
VG_(get_IP)(VG_(get_running_tid)()),
"Destruction of a barrier with active waiters",
&bei);
}
DRD_(clientobj_remove)(p->a1, ClientBarrier);
}
/** Called before pthread_barrier_wait() / gomp_barrier_wait(). */
void DRD_(barrier_pre_wait)(const DrdThreadId tid, const Addr barrier,
const BarrierT barrier_type)
{
struct barrier_info* p;
struct barrier_thread_info* q;
const UWord word_tid = tid;
OSet* oset;
p = DRD_(barrier_get)(barrier);
if (p == 0 && barrier_type == gomp_barrier) {
/*
* gomp_barrier_wait() call has been intercepted but gomp_barrier_init()
* not. The only cause I know of that can trigger this is that libgomp.so
* has been compiled with --enable-linux-futex.
*/
BarrierErrInfo bei = { DRD_(thread_get_running_tid)(), 0, 0, 0 };
VG_(maybe_record_error)(VG_(get_running_tid)(),
BarrierErr,
VG_(get_IP)(VG_(get_running_tid)()),
"Please verify whether gcc has been configured"
" with option --disable-linux-futex. See also"
" the section about OpenMP in the DRD manual.",
&bei);
}
tl_assert(p);
if (s_trace_barrier)
DRD_(trace_msg)("[%d] barrier_pre_wait %s 0x%lx iteration %ld",
DRD_(thread_get_running_tid)(),
barrier_get_typename(p), barrier, p->pre_iteration);
/* Clean up nodes associated with finished threads. */
oset = p->oset[p->pre_iteration & 1];
tl_assert(oset);
VG_(OSetGen_ResetIter)(oset);
for ( ; (q = VG_(OSetGen_Next)(oset)) != 0; ) {
if (q->thread_finished) {
void* r = VG_(OSetGen_Remove)(oset, &q->tid);
tl_assert(r == q);
DRD_(barrier_thread_destroy)(q);
VG_(OSetGen_FreeNode)(oset, q);
VG_(OSetGen_ResetIterAt)(oset, &word_tid);
}
}
/* Allocate the per-thread data structure if necessary. */
q = VG_(OSetGen_Lookup)(oset, &word_tid);
if (q == NULL) {
q = VG_(OSetGen_AllocNode)(oset, sizeof(*q));
DRD_(barrier_thread_initialize)(q, tid);
VG_(OSetGen_Insert)(oset, q);
tl_assert(VG_(OSetGen_Lookup)(oset, &word_tid) == q);
}
/* Record *_barrier_wait() call context. */
q->wait_call_ctxt = VG_(record_ExeContext)(VG_(get_running_tid)(), 0);
/*
* Store a pointer to the latest segment of the current thread in the
* per-thread data structure.
*/
DRD_(thread_get_latest_segment)(&q->sg, tid);
/*
* If the same number of threads as the barrier count indicates have
* called the pre *_barrier_wait() wrapper, toggle p->pre_iteration and
* reset the p->pre_waiters_left counter.
*/
if (--p->pre_waiters_left <= 0)
{
p->pre_iteration++;
p->pre_waiters_left = p->count;
}
}
/** Called after pthread_barrier_wait() / gomp_barrier_wait(). */
void DRD_(barrier_post_wait)(const DrdThreadId tid, const Addr barrier,
const BarrierT barrier_type, const Bool waited,
const Bool serializing)
{
struct barrier_info* p;
const UWord word_tid = tid;
struct barrier_thread_info* q;
struct barrier_thread_info* r;
OSet* oset;
p = DRD_(barrier_get)(barrier);
if (s_trace_barrier)
DRD_(trace_msg)("[%d] barrier_post_wait %s 0x%lx iteration %ld%s",
tid, p ? barrier_get_typename(p) : "(?)",
barrier, p ? p->post_iteration : -1,
serializing ? " (serializing)" : "");
/*
* If p == 0, this means that the barrier has been destroyed after
* *_barrier_wait() returned and before this function was called. Just
* return in that case -- race conditions between *_barrier_wait()
* and *_barrier_destroy() are detected by the *_barrier_destroy() wrapper.
*/
if (p == 0)
return;
/* If the *_barrier_wait() call returned an error code, exit. */
if (! waited)
return;
oset = p->oset[p->post_iteration & 1];
q = VG_(OSetGen_Lookup)(oset, &word_tid);
if (p->pre_iteration - p->post_iteration > 1) {
BarrierErrInfo bei = { DRD_(thread_get_running_tid)(), p->a1, 0, 0 };
VG_(maybe_record_error)(VG_(get_running_tid)(),
BarrierErr,
VG_(get_IP)(VG_(get_running_tid)()),
"Number of concurrent pthread_barrier_wait()"
" calls exceeds the barrier count",
&bei);
} else if (q == NULL) {
BarrierErrInfo bei = { DRD_(thread_get_running_tid)(), p->a1, 0, 0 };
VG_(maybe_record_error)(VG_(get_running_tid)(),
BarrierErr,
VG_(get_IP)(VG_(get_running_tid)()),
"Error in barrier implementation"
" -- barrier_wait() started before"
" barrier_destroy() and finished after"
" barrier_destroy()",
&bei);
}
if (q == NULL) {
q = VG_(OSetGen_AllocNode)(oset, sizeof(*q));
DRD_(barrier_thread_initialize)(q, tid);
VG_(OSetGen_Insert)(oset, q);
tl_assert(VG_(OSetGen_Lookup)(oset, &word_tid) == q);
DRD_(thread_get_latest_segment)(&q->sg, tid);
}
/* Create a new segment and store a pointer to that segment. */
DRD_(thread_new_segment)(tid);
DRD_(thread_get_latest_segment)(&q->post_wait_sg, tid);
s_barrier_segment_creation_count++;
/*
* Combine all vector clocks that were stored in the pre_barrier_wait
* wrapper with the vector clock of the current thread.
*/
{
VectorClock old_vc;
DRD_(vc_copy)(&old_vc, DRD_(thread_get_vc)(tid));
VG_(OSetGen_ResetIter)(oset);
for ( ; (r = VG_(OSetGen_Next)(oset)) != 0; )
{
if (r != q)
{
tl_assert(r->sg);
DRD_(vc_combine)(DRD_(thread_get_vc)(tid), &r->sg->vc);
}
}
DRD_(thread_update_conflict_set)(tid, &old_vc);
DRD_(vc_cleanup)(&old_vc);
}
/*
* If the same number of threads as the barrier count indicates have
* called the post *_barrier_wait() wrapper, toggle p->post_iteration and
* reset the p->post_waiters_left counter.
*/
if (--p->post_waiters_left <= 0)
{
p->post_iteration++;
p->post_waiters_left = p->count;
}
}
/** Called when thread tid stops to exist. */
static void barrier_delete_thread(struct barrier_info* const p,
const DrdThreadId tid)
{
struct barrier_thread_info* q;
const UWord word_tid = tid;
int i;
for (i = 0; i < 2; i++) {
q = VG_(OSetGen_Lookup)(p->oset[i], &word_tid);
if (q)
q->thread_finished = True;
}
}
/**
* Report that *_barrier_destroy() has been called but that this call was
* not synchronized with the last *_barrier_wait() call on the same barrier.
*
* This topic has been discussed extensively on comp.programming.threads
* (February 3, 2009). See also
* <a href="http://groups.google.com/group/comp.programming.threads/browse_thread/thread/4f65535d6192aa50/a5f4bf1e3b437c4d">Immediately destroying pthread barriers</a>.
*/
static
void barrier_report_wait_delete_race(const struct barrier_info* const p,
const struct barrier_thread_info* const q)
{
tl_assert(p);
tl_assert(q);
{
BarrierErrInfo bei
= { DRD_(thread_get_running_tid)(), p->a1, q->tid, q->wait_call_ctxt };
VG_(maybe_record_error)(VG_(get_running_tid)(),
BarrierErr,
VG_(get_IP)(VG_(get_running_tid)()),
"Destruction of barrier not synchronized with"
" barrier wait call",
&bei);
}
}
static const char* barrier_get_typename(struct barrier_info* const p)
{
tl_assert(p);
return barrier_type_name(p->barrier_type);
}
static const char* barrier_type_name(const BarrierT bt)
{
switch (bt)
{
case pthread_barrier:
return "pthread barrier";
case gomp_barrier:
return "gomp barrier";
}
return "?";
}
ULong DRD_(get_barrier_segment_creation_count)(void)
{
return s_barrier_segment_creation_count;
}