- Copy stable/10 (r259064) to releng/10.0 as part of the

[FreeBSD/releng/10.0.git] / cddl / contrib / opensolaris / tools / ctf / cvt / ctfmerge.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I%     %E% SMI"

/*
 * Given several files containing CTF data, merge and uniquify that data into
 * a single CTF section in an output file.
 *
 * Merges can proceed independently.  As such, we perform the merges in parallel
 * using a worker thread model.  A given glob of CTF data (either all of the CTF
 * data from a single input file, or the result of one or more merges) can only
 * be involved in a single merge at any given time, so the process decreases in
 * parallelism, especially towards the end, as more and more files are
 * consolidated, finally resulting in a single merge of two large CTF graphs.
 * Unfortunately, the last merge is also the slowest, as the two graphs being
 * merged are each the product of merges of half of the input files.
 *
 * The algorithm consists of two phases, described in detail below.  The first
 * phase entails the merging of CTF data in groups of eight.  The second phase
 * takes the results of Phase I, and merges them two at a time.  This disparity
 * is due to an observation that the merge time increases at least quadratically
 * with the size of the CTF data being merged.  As such, merges of CTF graphs
 * newly read from input files are much faster than merges of CTF graphs that
 * are themselves the results of prior merges.
 *
 * A further complication is the need to ensure the repeatability of CTF merges.
 * That is, a merge should produce the same output every time, given the same
 * input.  In both phases, this consistency requirement is met by imposing an
 * ordering on the merge process, thus ensuring that a given set of input files
 * are merged in the same order every time.
 *
 *   Phase I
 *
 *   The main thread reads the input files one by one, transforming the CTF
 *   data they contain into tdata structures.  When a given file has been read
 *   and parsed, it is placed on the work queue for retrieval by worker threads.
 *
 *   Central to Phase I is the Work In Progress (wip) array, which is used to
 *   merge batches of files in a predictable order.  Files are read by the main
 *   thread, and are merged into wip array elements in round-robin order.  When
 *   the number of files merged into a given array slot equals the batch size,
 *   the merged CTF graph in that array is added to the done slot in order by
 *   array slot.
 *
 *   For example, consider a case where we have five input files, a batch size
 *   of two, a wip array size of two, and two worker threads (T1 and T2).
 *
 *    1. The wip array elements are assigned initial batch numbers 0 and 1.
 *    2. T1 reads an input file from the input queue (wq_queue).  This is the
 *       first input file, so it is placed into wip[0].  The second file is
 *       similarly read and placed into wip[1].  The wip array slots now contain
 *       one file each (wip_nmerged == 1).
 *    3. T1 reads the third input file, which it merges into wip[0].  The
 *       number of files in wip[0] is equal to the batch size.
 *    4. T2 reads the fourth input file, which it merges into wip[1].  wip[1]
 *       is now full too.
 *    5. T2 attempts to place the contents of wip[1] on the done queue
 *       (wq_done_queue), but it can't, since the batch ID for wip[1] is 1.
 *       Batch 0 needs to be on the done queue before batch 1 can be added, so
 *       T2 blocks on wip[1]'s cv.
 *    6. T1 attempts to place the contents of wip[0] on the done queue, and
 *       succeeds, updating wq_lastdonebatch to 0.  It clears wip[0], and sets
 *       its batch ID to 2.  T1 then signals wip[1]'s cv to awaken T2.
 *    7. T2 wakes up, notices that wq_lastdonebatch is 0, which means that
 *       batch 1 can now be added.  It adds wip[1] to the done queue, clears
 *       wip[1], and sets its batch ID to 3.  It signals wip[0]'s cv, and
 *       restarts.
 *
 *   The above process continues until all input files have been consumed.  At
 *   this point, a pair of barriers are used to allow a single thread to move
 *   any partial batches from the wip array to the done array in batch ID order.
 *   When this is complete, wq_done_queue is moved to wq_queue, and Phase II
 *   begins.
 *
 *      Locking Semantics (Phase I)
 *
 *      The input queue (wq_queue) and the done queue (wq_done_queue) are
 *      protected by separate mutexes - wq_queue_lock and wq_done_queue.  wip
 *      array slots are protected by their own mutexes, which must be grabbed
 *      before releasing the input queue lock.  The wip array lock is dropped
 *      when the thread restarts the loop.  If the array slot was full, the
 *      array lock will be held while the slot contents are added to the done
 *      queue.  The done queue lock is used to protect the wip slot cv's.
 *
 *      The pow number is protected by the queue lock.  The master batch ID
 *      and last completed batch (wq_lastdonebatch) counters are protected *in
 *      Phase I* by the done queue lock.
 *
 *   Phase II
 *
 *   When Phase II begins, the queue consists of the merged batches from the
 *   first phase.  Assume we have five batches:
 *
 *      Q:      a b c d e
 *
 *   Using the same batch ID mechanism we used in Phase I, but without the wip
 *   array, worker threads remove two entries at a time from the beginning of
 *   the queue.  These two entries are merged, and are added back to the tail
 *   of the queue, as follows:
 *
 *      Q:      a b c d e       # start
 *      Q:      c d e ab        # a, b removed, merged, added to end
 *      Q:      e ab cd         # c, d removed, merged, added to end
 *      Q:      cd eab          # e, ab removed, merged, added to end
 *      Q:      cdeab           # cd, eab removed, merged, added to end
 *
 *   When one entry remains on the queue, with no merges outstanding, Phase II
 *   finishes.  We pre-determine the stopping point by pre-calculating the
 *   number of nodes that will appear on the list.  In the example above, the
 *   number (wq_ninqueue) is 9.  When ninqueue is 1, we conclude Phase II by
 *   signaling the main thread via wq_done_cv.
 *
 *      Locking Semantics (Phase II)
 *
 *      The queue (wq_queue), ninqueue, and the master batch ID and last
 *      completed batch counters are protected by wq_queue_lock.  The done
 *      queue and corresponding lock are unused in Phase II as is the wip array.
 *
 *   Uniquification
 *
 *   We want the CTF data that goes into a given module to be as small as
 *   possible.  For example, we don't want it to contain any type data that may
 *   be present in another common module.  As such, after creating the master
 *   tdata_t for a given module, we can, if requested by the user, uniquify it
 *   against the tdata_t from another module (genunix in the case of the SunOS
 *   kernel).  We perform a merge between the tdata_t for this module and the
 *   tdata_t from genunix.  Nodes found in this module that are not present in
 *   genunix are added to a third tdata_t - the uniquified tdata_t.
 *
 *   Additive Merges
 *
 *   In some cases, for example if we are issuing a new version of a common
 *   module in a patch, we need to make sure that the CTF data already present
 *   in that module does not change.  Changes to this data would void the CTF
 *   data in any module that uniquified against the common module.  To preserve
 *   the existing data, we can perform what is known as an additive merge.  In
 *   this case, a final uniquification is performed against the CTF data in the
 *   previous version of the module.  The result will be the placement of new
 *   and changed data after the existing data, thus preserving the existing type
 *   ID space.
 *
 *   Saving the result
 *
 *   When the merges are complete, the resulting tdata_t is placed into the
 *   output file, replacing the .SUNW_ctf section (if any) already in that file.
 *
 * The person who changes the merging thread code in this file without updating
 * this comment will not live to see the stock hit five.
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <pthread.h>
#include <assert.h>
#if defined(sun)
#include <synch.h>
#endif
#include <signal.h>
#include <libgen.h>
#include <string.h>
#include <errno.h>
#if defined(sun)
#include <alloca.h>
#endif
#include <sys/param.h>
#include <sys/types.h>
#include <sys/mman.h>
#if defined(sun)
#include <sys/sysconf.h>
#endif

#include "ctf_headers.h"
#include "ctftools.h"
#include "ctfmerge.h"
#include "traverse.h"
#include "memory.h"
#include "fifo.h"
#include "barrier.h"

#pragma init(bigheap)

#define MERGE_PHASE1_BATCH_SIZE         8
#define MERGE_PHASE1_MAX_SLOTS          5
#define MERGE_INPUT_THROTTLE_LEN        10

const char *progname;
static char *outfile = NULL;
static char *tmpname = NULL;
static int dynsym;
int debug_level = DEBUG_LEVEL;
static size_t maxpgsize = 0x400000;


void
usage(void)
{
        (void) fprintf(stderr,
            "Usage: %s [-fgstv] -l label | -L labelenv -o outfile file ...\n"
            "       %s [-fgstv] -l label | -L labelenv -o outfile -d uniqfile\n"
            "       %*s [-g] [-D uniqlabel] file ...\n"
            "       %s [-fgstv] -l label | -L labelenv -o outfile -w withfile "
            "file ...\n"
            "       %s [-g] -c srcfile destfile\n"
            "\n"
            "  Note: if -L labelenv is specified and labelenv is not set in\n"
            "  the environment, a default value is used.\n",
            progname, progname, (int)strlen(progname), " ",
            progname, progname);
}

#if defined(sun)
static void
bigheap(void)
{
        size_t big, *size;
        int sizes;
        struct memcntl_mha mha;

        /*
         * First, get the available pagesizes.
         */
        if ((sizes = getpagesizes(NULL, 0)) == -1)
                return;

        if (sizes == 1 || (size = alloca(sizeof (size_t) * sizes)) == NULL)
                return;

        if (getpagesizes(size, sizes) == -1)
                return;

        while (size[sizes - 1] > maxpgsize)
                sizes--;

        /* set big to the largest allowed page size */
        big = size[sizes - 1];
        if (big & (big - 1)) {
                /*
                 * The largest page size is not a power of two for some
                 * inexplicable reason; return.
                 */
                return;
        }

        /*
         * Now, align our break to the largest page size.
         */
        if (brk((void *)((((uintptr_t)sbrk(0) - 1) & ~(big - 1)) + big)) != 0)
                return;

        /*
         * set the preferred page size for the heap
         */
        mha.mha_cmd = MHA_MAPSIZE_BSSBRK;
        mha.mha_flags = 0;
        mha.mha_pagesize = big;

        (void) memcntl(NULL, 0, MC_HAT_ADVISE, (caddr_t)&mha, 0, 0);
}
#endif

static void
finalize_phase_one(workqueue_t *wq)
{
        int startslot, i;

        /*
         * wip slots are cleared out only when maxbatchsz td's have been merged
         * into them.  We're not guaranteed that the number of files we're
         * merging is a multiple of maxbatchsz, so there will be some partial
         * groups in the wip array.  Move them to the done queue in batch ID
         * order, starting with the slot containing the next batch that would
         * have been placed on the done queue, followed by the others.
         * One thread will be doing this while the others wait at the barrier
         * back in worker_thread(), so we don't need to worry about pesky things
         * like locks.
         */

        for (startslot = -1, i = 0; i < wq->wq_nwipslots; i++) {
                if (wq->wq_wip[i].wip_batchid == wq->wq_lastdonebatch + 1) {
                        startslot = i;
                        break;
                }
        }

        assert(startslot != -1);

        for (i = startslot; i < startslot + wq->wq_nwipslots; i++) {
                int slotnum = i % wq->wq_nwipslots;
                wip_t *wipslot = &wq->wq_wip[slotnum];

                if (wipslot->wip_td != NULL) {
                        debug(2, "clearing slot %d (%d) (saving %d)\n",
                            slotnum, i, wipslot->wip_nmerged);
                } else
                        debug(2, "clearing slot %d (%d)\n", slotnum, i);

                if (wipslot->wip_td != NULL) {
                        fifo_add(wq->wq_donequeue, wipslot->wip_td);
                        wq->wq_wip[slotnum].wip_td = NULL;
                }
        }

        wq->wq_lastdonebatch = wq->wq_next_batchid++;

        debug(2, "phase one done: donequeue has %d items\n",
            fifo_len(wq->wq_donequeue));
}

static void
init_phase_two(workqueue_t *wq)
{
        int num;

        /*
         * We're going to continually merge the first two entries on the queue,
         * placing the result on the end, until there's nothing left to merge.
         * At that point, everything will have been merged into one.  The
         * initial value of ninqueue needs to be equal to the total number of
         * entries that will show up on the queue, both at the start of the
         * phase and as generated by merges during the phase.
         */
        wq->wq_ninqueue = num = fifo_len(wq->wq_donequeue);
        while (num != 1) {
                wq->wq_ninqueue += num / 2;
                num = num / 2 + num % 2;
        }

        /*
         * Move the done queue to the work queue.  We won't be using the done
         * queue in phase 2.
         */
        assert(fifo_len(wq->wq_queue) == 0);
        fifo_free(wq->wq_queue, NULL);
        wq->wq_queue = wq->wq_donequeue;
}

static void
wip_save_work(workqueue_t *wq, wip_t *slot, int slotnum)
{
        pthread_mutex_lock(&wq->wq_donequeue_lock);

        while (wq->wq_lastdonebatch + 1 < slot->wip_batchid)
                pthread_cond_wait(&slot->wip_cv, &wq->wq_donequeue_lock);
        assert(wq->wq_lastdonebatch + 1 == slot->wip_batchid);

        fifo_add(wq->wq_donequeue, slot->wip_td);
        wq->wq_lastdonebatch++;
        pthread_cond_signal(&wq->wq_wip[(slotnum + 1) %
            wq->wq_nwipslots].wip_cv);

        /* reset the slot for next use */
        slot->wip_td = NULL;
        slot->wip_batchid = wq->wq_next_batchid++;

        pthread_mutex_unlock(&wq->wq_donequeue_lock);
}

static void
wip_add_work(wip_t *slot, tdata_t *pow)
{
        if (slot->wip_td == NULL) {
                slot->wip_td = pow;
                slot->wip_nmerged = 1;
        } else {
                debug(2, "%d: merging %p into %p\n", pthread_self(),
                    (void *)pow, (void *)slot->wip_td);

                merge_into_master(pow, slot->wip_td, NULL, 0);
                tdata_free(pow);

                slot->wip_nmerged++;
        }
}

static void
worker_runphase1(workqueue_t *wq)
{
        wip_t *wipslot;
        tdata_t *pow;
        int wipslotnum, pownum;

        for (;;) {
                pthread_mutex_lock(&wq->wq_queue_lock);

                while (fifo_empty(wq->wq_queue)) {
                        if (wq->wq_nomorefiles == 1) {
                                pthread_cond_broadcast(&wq->wq_work_avail);
                                pthread_mutex_unlock(&wq->wq_queue_lock);

                                /* on to phase 2 ... */
                                return;
                        }

                        pthread_cond_wait(&wq->wq_work_avail,
                            &wq->wq_queue_lock);
                }

                /* there's work to be done! */
                pow = fifo_remove(wq->wq_queue);
                pownum = wq->wq_nextpownum++;
                pthread_cond_broadcast(&wq->wq_work_removed);

                assert(pow != NULL);

                /* merge it into the right slot */
                wipslotnum = pownum % wq->wq_nwipslots;
                wipslot = &wq->wq_wip[wipslotnum];

                pthread_mutex_lock(&wipslot->wip_lock);

                pthread_mutex_unlock(&wq->wq_queue_lock);

                wip_add_work(wipslot, pow);

                if (wipslot->wip_nmerged == wq->wq_maxbatchsz)
                        wip_save_work(wq, wipslot, wipslotnum);

                pthread_mutex_unlock(&wipslot->wip_lock);
        }
}

static void
worker_runphase2(workqueue_t *wq)
{
        tdata_t *pow1, *pow2;
        int batchid;

        for (;;) {
                pthread_mutex_lock(&wq->wq_queue_lock);

                if (wq->wq_ninqueue == 1) {
                        pthread_cond_broadcast(&wq->wq_work_avail);
                        pthread_mutex_unlock(&wq->wq_queue_lock);

                        debug(2, "%d: entering p2 completion barrier\n",
                            pthread_self());
                        if (barrier_wait(&wq->wq_bar1)) {
                                pthread_mutex_lock(&wq->wq_queue_lock);
                                wq->wq_alldone = 1;
                                pthread_cond_signal(&wq->wq_alldone_cv);
                                pthread_mutex_unlock(&wq->wq_queue_lock);
                        }

                        return;
                }

                if (fifo_len(wq->wq_queue) < 2) {
                        pthread_cond_wait(&wq->wq_work_avail,
                            &wq->wq_queue_lock);
                        pthread_mutex_unlock(&wq->wq_queue_lock);
                        continue;
                }

                /* there's work to be done! */
                pow1 = fifo_remove(wq->wq_queue);
                pow2 = fifo_remove(wq->wq_queue);
                wq->wq_ninqueue -= 2;

                batchid = wq->wq_next_batchid++;

                pthread_mutex_unlock(&wq->wq_queue_lock);

                debug(2, "%d: merging %p into %p\n", pthread_self(),
                    (void *)pow1, (void *)pow2);
                merge_into_master(pow1, pow2, NULL, 0);
                tdata_free(pow1);

                /*
                 * merging is complete.  place at the tail of the queue in
                 * proper order.
                 */
                pthread_mutex_lock(&wq->wq_queue_lock);
                while (wq->wq_lastdonebatch + 1 != batchid) {
                        pthread_cond_wait(&wq->wq_done_cv,
                            &wq->wq_queue_lock);
                }

                wq->wq_lastdonebatch = batchid;

                fifo_add(wq->wq_queue, pow2);
                debug(2, "%d: added %p to queue, len now %d, ninqueue %d\n",
                    pthread_self(), (void *)pow2, fifo_len(wq->wq_queue),
                    wq->wq_ninqueue);
                pthread_cond_broadcast(&wq->wq_done_cv);
                pthread_cond_signal(&wq->wq_work_avail);
                pthread_mutex_unlock(&wq->wq_queue_lock);
        }
}

/*
 * Main loop for worker threads.
 */
static void
worker_thread(workqueue_t *wq)
{
        worker_runphase1(wq);

        debug(2, "%d: entering first barrier\n", pthread_self());

        if (barrier_wait(&wq->wq_bar1)) {

                debug(2, "%d: doing work in first barrier\n", pthread_self());

                finalize_phase_one(wq);

                init_phase_two(wq);

                debug(2, "%d: ninqueue is %d, %d on queue\n", pthread_self(),
                    wq->wq_ninqueue, fifo_len(wq->wq_queue));
        }

        debug(2, "%d: entering second barrier\n", pthread_self());

        (void) barrier_wait(&wq->wq_bar2);

        debug(2, "%d: phase 1 complete\n", pthread_self());

        worker_runphase2(wq);
}

/*
 * Pass a tdata_t tree, built from an input file, off to the work queue for
 * consumption by worker threads.
 */
static int
merge_ctf_cb(tdata_t *td, char *name, void *arg)
{
        workqueue_t *wq = arg;

        debug(3, "Adding tdata %p for processing\n", (void *)td);

        pthread_mutex_lock(&wq->wq_queue_lock);
        while (fifo_len(wq->wq_queue) > wq->wq_ithrottle) {
                debug(2, "Throttling input (len = %d, throttle = %d)\n",
                    fifo_len(wq->wq_queue), wq->wq_ithrottle);
                pthread_cond_wait(&wq->wq_work_removed, &wq->wq_queue_lock);
        }

        fifo_add(wq->wq_queue, td);
        debug(1, "Thread %d announcing %s\n", pthread_self(), name);
        pthread_cond_broadcast(&wq->wq_work_avail);
        pthread_mutex_unlock(&wq->wq_queue_lock);

        return (1);
}

/*
 * This program is intended to be invoked from a Makefile, as part of the build.
 * As such, in the event of a failure or user-initiated interrupt (^C), we need
 * to ensure that a subsequent re-make will cause ctfmerge to be executed again.
 * Unfortunately, ctfmerge will usually be invoked directly after (and as part
 * of the same Makefile rule as) a link, and will operate on the linked file
 * in place.  If we merely exit upon receipt of a SIGINT, a subsequent make
 * will notice that the *linked* file is newer than the object files, and thus
 * will not reinvoke ctfmerge.  The only way to ensure that a subsequent make
 * reinvokes ctfmerge, is to remove the file to which we are adding CTF
 * data (confusingly named the output file).  This means that the link will need
 * to happen again, but links are generally fast, and we can't allow the merge
 * to be skipped.
 *
 * Another possibility would be to block SIGINT entirely - to always run to
 * completion.  The run time of ctfmerge can, however, be measured in minutes
 * in some cases, so this is not a valid option.
 */
static void
handle_sig(int sig)
{
        terminate("Caught signal %d - exiting\n", sig);
}

static void
terminate_cleanup(void)
{
        int dounlink = getenv("CTFMERGE_TERMINATE_NO_UNLINK") ? 0 : 1;

        if (tmpname != NULL && dounlink)
                unlink(tmpname);

        if (outfile == NULL)
                return;

#if !defined(__FreeBSD__)
        if (dounlink) {
                fprintf(stderr, "Removing %s\n", outfile);
                unlink(outfile);
        }
#endif
}

static void
copy_ctf_data(char *srcfile, char *destfile, int keep_stabs)
{
        tdata_t *srctd;

        if (read_ctf(&srcfile, 1, NULL, read_ctf_save_cb, &srctd, 1) == 0)
                terminate("No CTF data found in source file %s\n", srcfile);

        tmpname = mktmpname(destfile, ".ctf");
        write_ctf(srctd, destfile, tmpname, CTF_COMPRESS | CTF_SWAP_BYTES | keep_stabs);
        if (rename(tmpname, destfile) != 0) {
                terminate("Couldn't rename temp file %s to %s", tmpname,
                    destfile);
        }
        free(tmpname);
        tdata_free(srctd);
}

static void
wq_init(workqueue_t *wq, int nfiles)
{
        int throttle, nslots, i;

        if (getenv("CTFMERGE_MAX_SLOTS"))
                nslots = atoi(getenv("CTFMERGE_MAX_SLOTS"));
        else
                nslots = MERGE_PHASE1_MAX_SLOTS;

        if (getenv("CTFMERGE_PHASE1_BATCH_SIZE"))
                wq->wq_maxbatchsz = atoi(getenv("CTFMERGE_PHASE1_BATCH_SIZE"));
        else
                wq->wq_maxbatchsz = MERGE_PHASE1_BATCH_SIZE;

        nslots = MIN(nslots, (nfiles + wq->wq_maxbatchsz - 1) /
            wq->wq_maxbatchsz);

        wq->wq_wip = xcalloc(sizeof (wip_t) * nslots);
        wq->wq_nwipslots = nslots;
        wq->wq_nthreads = MIN(sysconf(_SC_NPROCESSORS_ONLN) * 3 / 2, nslots);
        wq->wq_thread = xmalloc(sizeof (pthread_t) * wq->wq_nthreads);

        if (getenv("CTFMERGE_INPUT_THROTTLE"))
                throttle = atoi(getenv("CTFMERGE_INPUT_THROTTLE"));
        else
                throttle = MERGE_INPUT_THROTTLE_LEN;
        wq->wq_ithrottle = throttle * wq->wq_nthreads;

        debug(1, "Using %d slots, %d threads\n", wq->wq_nwipslots,
            wq->wq_nthreads);

        wq->wq_next_batchid = 0;

        for (i = 0; i < nslots; i++) {
                pthread_mutex_init(&wq->wq_wip[i].wip_lock, NULL);
                wq->wq_wip[i].wip_batchid = wq->wq_next_batchid++;
        }

        pthread_mutex_init(&wq->wq_queue_lock, NULL);
        wq->wq_queue = fifo_new();
        pthread_cond_init(&wq->wq_work_avail, NULL);
        pthread_cond_init(&wq->wq_work_removed, NULL);
        wq->wq_ninqueue = nfiles;
        wq->wq_nextpownum = 0;

        pthread_mutex_init(&wq->wq_donequeue_lock, NULL);
        wq->wq_donequeue = fifo_new();
        wq->wq_lastdonebatch = -1;

        pthread_cond_init(&wq->wq_done_cv, NULL);

        pthread_cond_init(&wq->wq_alldone_cv, NULL);
        wq->wq_alldone = 0;

        barrier_init(&wq->wq_bar1, wq->wq_nthreads);
        barrier_init(&wq->wq_bar2, wq->wq_nthreads);

        wq->wq_nomorefiles = 0;
}

static void
start_threads(workqueue_t *wq)
{
        sigset_t sets;
        int i;

        sigemptyset(&sets);
        sigaddset(&sets, SIGINT);
        sigaddset(&sets, SIGQUIT);
        sigaddset(&sets, SIGTERM);
        pthread_sigmask(SIG_BLOCK, &sets, NULL);

        for (i = 0; i < wq->wq_nthreads; i++) {
                pthread_create(&wq->wq_thread[i], NULL,
                    (void *(*)(void *))worker_thread, wq);
        }

#if defined(sun)
        sigset(SIGINT, handle_sig);
        sigset(SIGQUIT, handle_sig);
        sigset(SIGTERM, handle_sig);
#else
        signal(SIGINT, handle_sig);
        signal(SIGQUIT, handle_sig);
        signal(SIGTERM, handle_sig);
#endif
        pthread_sigmask(SIG_UNBLOCK, &sets, NULL);
}

static void
join_threads(workqueue_t *wq)
{
        int i;

        for (i = 0; i < wq->wq_nthreads; i++) {
                pthread_join(wq->wq_thread[i], NULL);
        }
}

static int
strcompare(const void *p1, const void *p2)
{
        char *s1 = *((char **)p1);
        char *s2 = *((char **)p2);

        return (strcmp(s1, s2));
}

/*
 * Core work queue structure; passed to worker threads on thread creation
 * as the main point of coordination.  Allocate as a static structure; we
 * could have put this into a local variable in main, but passing a pointer
 * into your stack to another thread is fragile at best and leads to some
 * hard-to-debug failure modes.
 */
static workqueue_t wq;

int
main(int argc, char **argv)
{
        tdata_t *mstrtd, *savetd;
        char *uniqfile = NULL, *uniqlabel = NULL;
        char *withfile = NULL;
        char *label = NULL;
        char **ifiles, **tifiles;
        int verbose = 0, docopy = 0;
        int write_fuzzy_match = 0;
        int keep_stabs = 0;
        int require_ctf = 0;
        int nifiles, nielems;
        int c, i, idx, tidx, err;

        progname = basename(argv[0]);

        if (getenv("CTFMERGE_DEBUG_LEVEL"))
                debug_level = atoi(getenv("CTFMERGE_DEBUG_LEVEL"));

        err = 0;
        while ((c = getopt(argc, argv, ":cd:D:fgl:L:o:tvw:s")) != EOF) {
                switch (c) {
                case 'c':
                        docopy = 1;
                        break;
                case 'd':
                        /* Uniquify against `uniqfile' */
                        uniqfile = optarg;
                        break;
                case 'D':
                        /* Uniquify against label `uniqlabel' in `uniqfile' */
                        uniqlabel = optarg;
                        break;
                case 'f':
                        write_fuzzy_match = CTF_FUZZY_MATCH;
                        break;
                case 'g':
                        keep_stabs = CTF_KEEP_STABS;
                        break;
                case 'l':
                        /* Label merged types with `label' */
                        label = optarg;
                        break;
                case 'L':
                        /* Label merged types with getenv(`label`) */
                        if ((label = getenv(optarg)) == NULL)
                                label = CTF_DEFAULT_LABEL;
                        break;
                case 'o':
                        /* Place merged types in CTF section in `outfile' */
                        outfile = optarg;
                        break;
                case 't':
                        /* Insist *all* object files built from C have CTF */
                        require_ctf = 1;
                        break;
                case 'v':
                        /* More debugging information */
                        verbose = 1;
                        break;
                case 'w':
                        /* Additive merge with data from `withfile' */
                        withfile = optarg;
                        break;
                case 's':
                        /* use the dynsym rather than the symtab */
                        dynsym = CTF_USE_DYNSYM;
                        break;
                default:
                        usage();
                        exit(2);
                }
        }

        /* Validate arguments */
        if (docopy) {
                if (uniqfile != NULL || uniqlabel != NULL || label != NULL ||
                    outfile != NULL || withfile != NULL || dynsym != 0)
                        err++;

                if (argc - optind != 2)
                        err++;
        } else {
                if (uniqfile != NULL && withfile != NULL)
                        err++;

                if (uniqlabel != NULL && uniqfile == NULL)
                        err++;

                if (outfile == NULL || label == NULL)
                        err++;

                if (argc - optind == 0)
                        err++;
        }

        if (err) {
                usage();
                exit(2);
        }

        if (getenv("STRIPSTABS_KEEP_STABS") != NULL)
                keep_stabs = CTF_KEEP_STABS;

        if (uniqfile && access(uniqfile, R_OK) != 0) {
                warning("Uniquification file %s couldn't be opened and "
                    "will be ignored.\n", uniqfile);
                uniqfile = NULL;
        }
        if (withfile && access(withfile, R_OK) != 0) {
                warning("With file %s couldn't be opened and will be "
                    "ignored.\n", withfile);
                withfile = NULL;
        }
        if (outfile && access(outfile, R_OK|W_OK) != 0)
                terminate("Cannot open output file %s for r/w", outfile);

        /*
         * This is ugly, but we don't want to have to have a separate tool
         * (yet) just for copying an ELF section with our specific requirements,
         * so we shoe-horn a copier into ctfmerge.
         */
        if (docopy) {
                copy_ctf_data(argv[optind], argv[optind + 1], keep_stabs);

                exit(0);
        }

        set_terminate_cleanup(terminate_cleanup);

        /* Sort the input files and strip out duplicates */
        nifiles = argc - optind;
        ifiles = xmalloc(sizeof (char *) * nifiles);
        tifiles = xmalloc(sizeof (char *) * nifiles);

        for (i = 0; i < nifiles; i++)
                tifiles[i] = argv[optind + i];
        qsort(tifiles, nifiles, sizeof (char *), (int (*)())strcompare);

        ifiles[0] = tifiles[0];
        for (idx = 0, tidx = 1; tidx < nifiles; tidx++) {
                if (strcmp(ifiles[idx], tifiles[tidx]) != 0)
                        ifiles[++idx] = tifiles[tidx];
        }
        nifiles = idx + 1;

        /* Make sure they all exist */
        if ((nielems = count_files(ifiles, nifiles)) < 0)
                terminate("Some input files were inaccessible\n");

        /* Prepare for the merge */
        wq_init(&wq, nielems);

        start_threads(&wq);

        /*
         * Start the merge
         *
         * We're reading everything from each of the object files, so we
         * don't need to specify labels.
         */
        if (read_ctf(ifiles, nifiles, NULL, merge_ctf_cb,
            &wq, require_ctf) == 0) {
                /*
                 * If we're verifying that C files have CTF, it's safe to
                 * assume that in this case, we're building only from assembly
                 * inputs.
                 */
                if (require_ctf)
                        exit(0);
                terminate("No ctf sections found to merge\n");
        }

        pthread_mutex_lock(&wq.wq_queue_lock);
        wq.wq_nomorefiles = 1;
        pthread_cond_broadcast(&wq.wq_work_avail);
        pthread_mutex_unlock(&wq.wq_queue_lock);

        pthread_mutex_lock(&wq.wq_queue_lock);
        while (wq.wq_alldone == 0)
                pthread_cond_wait(&wq.wq_alldone_cv, &wq.wq_queue_lock);
        pthread_mutex_unlock(&wq.wq_queue_lock);

        join_threads(&wq);

        /*
         * All requested files have been merged, with the resulting tree in
         * mstrtd.  savetd is the tree that will be placed into the output file.
         *
         * Regardless of whether we're doing a normal uniquification or an
         * additive merge, we need a type tree that has been uniquified
         * against uniqfile or withfile, as appropriate.
         *
         * If we're doing a uniquification, we stuff the resulting tree into
         * outfile.  Otherwise, we add the tree to the tree already in withfile.
         */
        assert(fifo_len(wq.wq_queue) == 1);
        mstrtd = fifo_remove(wq.wq_queue);

        if (verbose || debug_level) {
                debug(2, "Statistics for td %p\n", (void *)mstrtd);

                iidesc_stats(mstrtd->td_iihash);
        }

        if (uniqfile != NULL || withfile != NULL) {
                char *reffile, *reflabel = NULL;
                tdata_t *reftd;

                if (uniqfile != NULL) {
                        reffile = uniqfile;
                        reflabel = uniqlabel;
                } else
                        reffile = withfile;

                if (read_ctf(&reffile, 1, reflabel, read_ctf_save_cb,
                    &reftd, require_ctf) == 0) {
                        terminate("No CTF data found in reference file %s\n",
                            reffile);
                }

                savetd = tdata_new();

                if (CTF_TYPE_ISCHILD(reftd->td_nextid))
                        terminate("No room for additional types in master\n");

                savetd->td_nextid = withfile ? reftd->td_nextid :
                    CTF_INDEX_TO_TYPE(1, TRUE);
                merge_into_master(mstrtd, reftd, savetd, 0);

                tdata_label_add(savetd, label, CTF_LABEL_LASTIDX);

                if (withfile) {
                        /*
                         * savetd holds the new data to be added to the withfile
                         */
                        tdata_t *withtd = reftd;

                        tdata_merge(withtd, savetd);

                        savetd = withtd;
                } else {
                        char uniqname[MAXPATHLEN];
                        labelent_t *parle;

                        parle = tdata_label_top(reftd);

                        savetd->td_parlabel = xstrdup(parle->le_name);

                        strncpy(uniqname, reffile, sizeof (uniqname));
                        uniqname[MAXPATHLEN - 1] = '\0';
                        savetd->td_parname = xstrdup(basename(uniqname));
                }

        } else {
                /*
                 * No post processing.  Write the merged tree as-is into the
                 * output file.
                 */
                tdata_label_free(mstrtd);
                tdata_label_add(mstrtd, label, CTF_LABEL_LASTIDX);

                savetd = mstrtd;
        }

        tmpname = mktmpname(outfile, ".ctf");
        write_ctf(savetd, outfile, tmpname,
            CTF_COMPRESS | CTF_SWAP_BYTES | write_fuzzy_match | dynsym | keep_stabs);
        if (rename(tmpname, outfile) != 0)
                terminate("Couldn't rename output temp file %s", tmpname);
        free(tmpname);

        return (0);
}