/*
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_error.h"
#include "drd_segment.h"
#include "drd_thread.h"
#include "pub_tool_basics.h" // Addr, SizeT
#include "pub_tool_libcassert.h" // tl_assert()
#include "pub_tool_libcbase.h" // VG_(strlen)()
#include "pub_tool_libcprint.h" // VG_(printf)()
#include "pub_tool_machine.h" // VG_(get_SP)()
#include "pub_tool_mallocfree.h" // VG_(malloc)(), VG_(free)()
#include "pub_tool_threadstate.h" // VG_INVALID_THREADID
/* Global variables. */
Segment* DRD_(g_sg_list);
/* Local variables. */
static ULong s_segment_merge_count;
static ULong s_segments_created_count;
static ULong s_segments_alive_count;
static ULong s_max_segments_alive_count;
static Bool s_trace_segment;
/* Function definitions. */
/**
* Initialize the memory 'sg' points at.
*
* @note The creator and created thread ID's may be equal.
* @note This function copies the vector clock of thread 'creator', a technique
* also known as clock snooping. This will only work reliably if the thread
* that called pthread_create() waits until the created thread has copied
* the vector clock.
*/
static void sg_init(Segment* const sg,
const DrdThreadId creator,
const DrdThreadId created)
{
Segment* creator_sg;
ThreadId vg_created = DRD_(DrdThreadIdToVgThreadId)(created);
tl_assert(sg);
tl_assert(creator == DRD_INVALID_THREADID
|| DRD_(IsValidDrdThreadId)(creator));
creator_sg = (creator != DRD_INVALID_THREADID
? DRD_(thread_get_segment)(creator) : 0);
sg->g_next = NULL;
sg->g_prev = NULL;
sg->thr_next = NULL;
sg->thr_prev = NULL;
sg->tid = created;
sg->refcnt = 1;
if (vg_created != VG_INVALID_THREADID && VG_(get_SP)(vg_created) != 0)
sg->stacktrace = VG_(record_ExeContext)(vg_created, 0);
else
sg->stacktrace = 0;
if (creator_sg)
DRD_(vc_copy)(&sg->vc, &creator_sg->vc);
else
DRD_(vc_init)(&sg->vc, 0, 0);
DRD_(vc_increment)(&sg->vc, created);
DRD_(bm_init)(&sg->bm);
if (s_trace_segment)
{
char* vc;
vc = DRD_(vc_aprint)(&sg->vc);
VG_(message)(Vg_DebugMsg, "New segment for thread %d with vc %s\n",
created, vc);
VG_(free)(vc);
}
}
/** Deallocate the memory that was allocated by sg_init(). */
static void DRD_(sg_cleanup)(Segment* const sg)
{
tl_assert(sg);
tl_assert(sg->refcnt == 0);
DRD_(vc_cleanup)(&sg->vc);
DRD_(bm_cleanup)(&sg->bm);
}
/** Allocate and initialize a new segment. */
Segment* DRD_(sg_new)(const DrdThreadId creator, const DrdThreadId created)
{
Segment* sg;
s_segments_created_count++;
s_segments_alive_count++;
if (s_max_segments_alive_count < s_segments_alive_count)
s_max_segments_alive_count = s_segments_alive_count;
sg = VG_(malloc)("drd.segment.sn.1", sizeof(*sg));
tl_assert(sg);
sg_init(sg, creator, created);
if (DRD_(g_sg_list)) {
DRD_(g_sg_list)->g_prev = sg;
sg->g_next = DRD_(g_sg_list);
}
DRD_(g_sg_list) = sg;
return sg;
}
static void DRD_(sg_delete)(Segment* const sg)
{
if (DRD_(sg_get_trace)())
{
char* vc;
vc = DRD_(vc_aprint)(&sg->vc);
VG_(message)(Vg_DebugMsg, "Discarding the segment with vector clock %s\n",
vc);
VG_(free)(vc);
}
s_segments_alive_count--;
tl_assert(sg);
if (sg->g_next)
sg->g_next->g_prev = sg->g_prev;
if (sg->g_prev)
sg->g_prev->g_next = sg->g_next;
else
DRD_(g_sg_list) = sg->g_next;
DRD_(sg_cleanup)(sg);
VG_(free)(sg);
}
/** Increment the reference count of the specified segment. */
Segment* DRD_(sg_get)(Segment* const sg)
{
tl_assert(sg);
sg->refcnt++;
return sg;
}
/**
* Decrement the reference count of the specified segment and deallocate the
* segment if the reference count became zero.
*/
void DRD_(sg_put)(Segment* const sg)
{
if (sg == 0)
return;
if (s_trace_segment)
{
char* vc;
vc = DRD_(vc_aprint)(&sg->vc);
VG_(message)(Vg_DebugMsg,
"Decrementing segment reference count %d -> %d with vc %s\n",
sg->refcnt, sg->refcnt - 1, vc);
VG_(free)(vc);
}
tl_assert(sg->refcnt >= 1);
if (--sg->refcnt == 0)
{
DRD_(sg_delete)(sg);
}
}
/** Merge sg1 and sg2 into sg1. */
void DRD_(sg_merge)(Segment* const sg1, Segment* const sg2)
{
tl_assert(sg1);
tl_assert(sg1->refcnt == 1);
tl_assert(sg2);
tl_assert(sg2->refcnt == 1);
if (s_trace_segment)
{
char *vc1, *vc2;
vc1 = DRD_(vc_aprint)(&sg1->vc);
vc2 = DRD_(vc_aprint)(&sg2->vc);
VG_(message)(Vg_DebugMsg,
"Merging segments with vector clocks %s and %s\n", vc1, vc2);
VG_(free)(vc1);
VG_(free)(vc2);
}
s_segment_merge_count++;
// Keep sg1->stacktrace.
// Keep sg1->vc.
// Merge sg2->bm into sg1->bm.
DRD_(bm_merge2)(&sg1->bm, &sg2->bm);
}
/** Print the vector clock and the bitmap of the specified segment. */
void DRD_(sg_print)(Segment* const sg)
{
tl_assert(sg);
VG_(printf)("vc: ");
DRD_(vc_print)(&sg->vc);
VG_(printf)("\n");
DRD_(bm_print)(&sg->bm);
}
/** Query whether segment tracing has been enabled. */
Bool DRD_(sg_get_trace)(void)
{
return s_trace_segment;
}
/** Enable or disable segment tracing. */
void DRD_(sg_set_trace)(Bool const trace_segment)
{
tl_assert(trace_segment == False || trace_segment == True);
s_trace_segment = trace_segment;
}
ULong DRD_(sg_get_segments_created_count)(void)
{
return s_segments_created_count;
}
ULong DRD_(sg_get_segments_alive_count)(void)
{
return s_segments_alive_count;
}
ULong DRD_(sg_get_max_segments_alive_count)(void)
{
return s_max_segments_alive_count;
}
ULong DRD_(sg_get_segment_merge_count)(void)
{
return s_segment_merge_count;
}