MFC r304055:

[FreeBSD/stable/10.git] / cddl / contrib / opensolaris / tools / ctf / cvt / merge.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 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

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

/*
 * This file contains routines that merge one tdata_t tree, called the child,
 * into another, called the parent.  Note that these names are used mainly for
 * convenience and to represent the direction of the merge.  They are not meant
 * to imply any relationship between the tdata_t graphs prior to the merge.
 *
 * tdata_t structures contain two main elements - a hash of iidesc_t nodes, and
 * a directed graph of tdesc_t nodes, pointed to by the iidesc_t nodes.  Simply
 * put, we merge the tdesc_t graphs, followed by the iidesc_t nodes, and then we
 * clean up loose ends.
 *
 * The algorithm is as follows:
 *
 * 1. Mapping iidesc_t nodes
 *
 * For each child iidesc_t node, we first try to map its tdesc_t subgraph
 * against the tdesc_t graph in the parent.  For each node in the child subgraph
 * that exists in the parent, a mapping between the two (between their type IDs)
 * is established.  For the child nodes that cannot be mapped onto existing
 * parent nodes, a mapping is established between the child node ID and a
 * newly-allocated ID that the node will use when it is re-created in the
 * parent.  These unmappable nodes are added to the md_tdtba (tdesc_t To Be
 * Added) hash, which tracks nodes that need to be created in the parent.
 *
 * If all of the nodes in the subgraph for an iidesc_t in the child can be
 * mapped to existing nodes in the parent, then we can try to map the child
 * iidesc_t onto an iidesc_t in the parent.  If we cannot find an equivalent
 * iidesc_t, or if we were not able to completely map the tdesc_t subgraph(s),
 * then we add this iidesc_t to the md_iitba (iidesc_t To Be Added) list.  This
 * list tracks iidesc_t nodes that are to be created in the parent.
 *
 * While visiting the tdesc_t nodes, we may discover a forward declaration (a
 * FORWARD tdesc_t) in the parent that is resolved in the child.  That is, there
 * may be a structure or union definition in the child with the same name as the
 * forward declaration in the parent.  If we find such a node, we record an
 * association in the md_fdida (Forward => Definition ID Association) list
 * between the parent ID of the forward declaration and the ID that the
 * definition will use when re-created in the parent.
 *
 * 2. Creating new tdesc_t nodes (the md_tdtba hash)
 *
 * We have now attempted to map all tdesc_t nodes from the child into the
 * parent, and have, in md_tdtba, a hash of all tdesc_t nodes that need to be
 * created (or, as we so wittily call it, conjured) in the parent.  We iterate
 * through this hash, creating the indicated tdesc_t nodes.  For a given tdesc_t
 * node, conjuring requires two steps - the copying of the common tdesc_t data
 * (name, type, etc) from the child node, and the creation of links from the
 * newly-created node to the parent equivalents of other tdesc_t nodes pointed
 * to by node being conjured.  Note that in some cases, the targets of these
 * links will be on the md_tdtba hash themselves, and may not have been created
 * yet.  As such, we can't establish the links from these new nodes into the
 * parent graph.  We therefore conjure them with links to nodes in the *child*
 * graph, and add pointers to the links to be created to the md_tdtbr (tdesc_t
 * To Be Remapped) hash.  For example, a POINTER tdesc_t that could not be
 * resolved would have its &tdesc_t->t_tdesc added to md_tdtbr.
 *
 * 3. Creating new iidesc_t nodes (the md_iitba list)
 *
 * When we have completed step 2, all tdesc_t nodes have been created (or
 * already existed) in the parent.  Some of them may have incorrect links (the
 * members of the md_tdtbr list), but they've all been created.  As such, we can
 * create all of the iidesc_t nodes, as we can attach the tdesc_t subgraph
 * pointers correctly.  We create each node, and attach the pointers to the
 * appropriate parts of the parent tdesc_t graph.
 *
 * 4. Resolving newly-created tdesc_t node links (the md_tdtbr list)
 *
 * As in step 3, we rely on the fact that all of the tdesc_t nodes have been
 * created.  Each entry in the md_tdtbr list is a pointer to where a link into
 * the parent will be established.  As saved in the md_tdtbr list, these
 * pointers point into the child tdesc_t subgraph.  We can thus get the target
 * type ID from the child, look at the ID mapping to determine the desired link
 * target, and redirect the link accordingly.
 *
 * 5. Parent => child forward declaration resolution
 *
 * If entries were made in the md_fdida list in step 1, we have forward
 * declarations in the parent that need to be resolved to their definitions
 * re-created in step 2 from the child.  Using the md_fdida list, we can locate
 * the definition for the forward declaration, and we can redirect all inbound
 * edges to the forward declaration node to the actual definition.
 *
 * A pox on the house of anyone who changes the algorithm without updating
 * this comment.
 */

#include <stdio.h>
#include <strings.h>
#include <assert.h>
#include <pthread.h>

#include "ctf_headers.h"
#include "ctftools.h"
#include "list.h"
#include "alist.h"
#include "memory.h"
#include "traverse.h"

typedef struct equiv_data equiv_data_t;
typedef struct merge_cb_data merge_cb_data_t;

/*
 * There are two traversals in this file, for equivalency and for tdesc_t
 * re-creation, that do not fit into the tdtraverse() framework.  We have our
 * own traversal mechanism and ops vector here for those two cases.
 */
typedef struct tdesc_ops {
        const char *name;
        int (*equiv)(tdesc_t *, tdesc_t *, equiv_data_t *);
        tdesc_t *(*conjure)(tdesc_t *, int, merge_cb_data_t *);
} tdesc_ops_t;
extern tdesc_ops_t tdesc_ops[];

/*
 * The workhorse structure of tdata_t merging.  Holds all lists of nodes to be
 * processed during various phases of the merge algorithm.
 */
struct merge_cb_data {
        tdata_t *md_parent;
        tdata_t *md_tgt;
        alist_t *md_ta;         /* Type Association */
        alist_t *md_fdida;      /* Forward -> Definition ID Association */
        list_t  **md_iitba;     /* iidesc_t nodes To Be Added to the parent */
        hash_t  *md_tdtba;      /* tdesc_t nodes To Be Added to the parent */
        list_t  **md_tdtbr;     /* tdesc_t nodes To Be Remapped */
        int md_flags;
}; /* merge_cb_data_t */

/*
 * When we first create a tdata_t from stabs data, we will have duplicate nodes.
 * Normal merges, however, assume that the child tdata_t is already self-unique,
 * and for speed reasons do not attempt to self-uniquify.  If this flag is set,
 * the merge algorithm will self-uniquify by avoiding the insertion of
 * duplicates in the md_tdtdba list.
 */
#define MCD_F_SELFUNIQUIFY      0x1

/*
 * When we merge the CTF data for the modules, we don't want it to contain any
 * data that can be found in the reference module (usually genunix).  If this
 * flag is set, we're doing a merge between the fully merged tdata_t for this
 * module and the tdata_t for the reference module, with the data unique to this
 * module ending up in a third tdata_t.  It is this third tdata_t that will end
 * up in the .SUNW_ctf section for the module.
 */
#define MCD_F_REFMERGE  0x2

/*
 * Mapping of child type IDs to parent type IDs
 */

static void
add_mapping(alist_t *ta, tid_t srcid, tid_t tgtid)
{
        debug(3, "Adding mapping %u <%x> => %u <%x>\n", srcid, srcid, tgtid, tgtid);

        assert(!alist_find(ta, (void *)(uintptr_t)srcid, NULL));
        assert(srcid != 0 && tgtid != 0);

        alist_add(ta, (void *)(uintptr_t)srcid, (void *)(uintptr_t)tgtid);
}

static tid_t
get_mapping(alist_t *ta, int srcid)
{
        void *ltgtid;

        if (alist_find(ta, (void *)(uintptr_t)srcid, (void **)&ltgtid))
                return ((uintptr_t)ltgtid);
        else
                return (0);
}

/*
 * Determining equivalence of tdesc_t subgraphs
 */

struct equiv_data {
        alist_t *ed_ta;
        tdesc_t *ed_node;
        tdesc_t *ed_tgt;

        int ed_clear_mark;
        int ed_cur_mark;
        int ed_selfuniquify;
}; /* equiv_data_t */

static int equiv_node(tdesc_t *, tdesc_t *, equiv_data_t *);

/*ARGSUSED2*/
static int
equiv_intrinsic(tdesc_t *stdp, tdesc_t *ttdp, equiv_data_t *ed __unused)
{
        intr_t *si = stdp->t_intr;
        intr_t *ti = ttdp->t_intr;

        if (si->intr_type != ti->intr_type ||
            si->intr_signed != ti->intr_signed ||
            si->intr_offset != ti->intr_offset ||
            si->intr_nbits != ti->intr_nbits)
                return (0);

        if (si->intr_type == INTR_INT &&
            si->intr_iformat != ti->intr_iformat)
                return (0);
        else if (si->intr_type == INTR_REAL &&
            si->intr_fformat != ti->intr_fformat)
                return (0);

        return (1);
}

static int
equiv_plain(tdesc_t *stdp, tdesc_t *ttdp, equiv_data_t *ed)
{
        return (equiv_node(stdp->t_tdesc, ttdp->t_tdesc, ed));
}

static int
equiv_function(tdesc_t *stdp, tdesc_t *ttdp, equiv_data_t *ed)
{
        fndef_t *fn1 = stdp->t_fndef, *fn2 = ttdp->t_fndef;
        int i;

        if (fn1->fn_nargs != fn2->fn_nargs ||
            fn1->fn_vargs != fn2->fn_vargs)
                return (0);

        if (!equiv_node(fn1->fn_ret, fn2->fn_ret, ed))
                return (0);

        for (i = 0; i < (int) fn1->fn_nargs; i++) {
                if (!equiv_node(fn1->fn_args[i], fn2->fn_args[i], ed))
                        return (0);
        }

        return (1);
}

static int
equiv_array(tdesc_t *stdp, tdesc_t *ttdp, equiv_data_t *ed)
{
        ardef_t *ar1 = stdp->t_ardef, *ar2 = ttdp->t_ardef;

        if (!equiv_node(ar1->ad_contents, ar2->ad_contents, ed) ||
            !equiv_node(ar1->ad_idxtype, ar2->ad_idxtype, ed))
                return (0);

        if (ar1->ad_nelems != ar2->ad_nelems)
                return (0);

        return (1);
}

static int
equiv_su(tdesc_t *stdp, tdesc_t *ttdp, equiv_data_t *ed)
{
        mlist_t *ml1 = stdp->t_members, *ml2 = ttdp->t_members;
        mlist_t *olm1 = NULL;

        while (ml1 && ml2) {
                if (ml1->ml_offset != ml2->ml_offset ||
                    strcmp(ml1->ml_name, ml2->ml_name) != 0)
                        return (0);

                /*
                 * Don't do the recursive equivalency checking more than
                 * we have to.
                 */
                if (olm1 == NULL || olm1->ml_type->t_id != ml1->ml_type->t_id) {
                        if (ml1->ml_size != ml2->ml_size ||
                            !equiv_node(ml1->ml_type, ml2->ml_type, ed))
                                return (0);
                }

                olm1 = ml1;
                ml1 = ml1->ml_next;
                ml2 = ml2->ml_next;
        }

        if (ml1 || ml2)
                return (0);

        return (1);
}

/*ARGSUSED2*/
static int
equiv_enum(tdesc_t *stdp, tdesc_t *ttdp, equiv_data_t *ed __unused)
{
        elist_t *el1 = stdp->t_emem;
        elist_t *el2 = ttdp->t_emem;

        while (el1 && el2) {
                if (el1->el_number != el2->el_number ||
                    strcmp(el1->el_name, el2->el_name) != 0)
                        return (0);

                el1 = el1->el_next;
                el2 = el2->el_next;
        }

        if (el1 || el2)
                return (0);

        return (1);
}

/*ARGSUSED*/
static int
equiv_assert(tdesc_t *stdp __unused, tdesc_t *ttdp __unused, equiv_data_t *ed __unused)
{
        /* foul, evil, and very bad - this is a "shouldn't happen" */
        assert(1 == 0);

        return (0);
}

static int
fwd_equiv(tdesc_t *ctdp, tdesc_t *mtdp)
{
        tdesc_t *defn = (ctdp->t_type == FORWARD ? mtdp : ctdp);

        return (defn->t_type == STRUCT || defn->t_type == UNION ||
            defn->t_type == ENUM);
}

static int
equiv_node(tdesc_t *ctdp, tdesc_t *mtdp, equiv_data_t *ed)
{
        int (*equiv)(tdesc_t *, tdesc_t *, equiv_data_t *);
        int mapping;

        if (ctdp->t_emark > ed->ed_clear_mark &&
            mtdp->t_emark > ed->ed_clear_mark)
                return (ctdp->t_emark == mtdp->t_emark);

        /*
         * In normal (non-self-uniquify) mode, we don't want to do equivalency
         * checking on a subgraph that has already been checked.  If a mapping
         * has already been established for a given child node, we can simply
         * compare the mapping for the child node with the ID of the parent
         * node.  If we are in self-uniquify mode, then we're comparing two
         * subgraphs within the child graph, and thus need to ignore any
         * type mappings that have been created, as they are only valid into the
         * parent.
         */
        if ((mapping = get_mapping(ed->ed_ta, ctdp->t_id)) > 0 &&
            mapping == mtdp->t_id && !ed->ed_selfuniquify)
                return (1);

        if (!streq(ctdp->t_name, mtdp->t_name))
                return (0);

        if (ctdp->t_type != mtdp->t_type) {
                if (ctdp->t_type == FORWARD || mtdp->t_type == FORWARD)
                        return (fwd_equiv(ctdp, mtdp));
                else
                        return (0);
        }

        ctdp->t_emark = ed->ed_cur_mark;
        mtdp->t_emark = ed->ed_cur_mark;
        ed->ed_cur_mark++;

        if ((equiv = tdesc_ops[ctdp->t_type].equiv) != NULL)
                return (equiv(ctdp, mtdp, ed));

        return (1);
}

/*
 * We perform an equivalency check on two subgraphs by traversing through them
 * in lockstep.  If a given node is equivalent in both the parent and the child,
 * we mark it in both subgraphs, using the t_emark field, with a monotonically
 * increasing number.  If, in the course of the traversal, we reach a node that
 * we have visited and numbered during this equivalency check, we have a cycle.
 * If the previously-visited nodes don't have the same emark, then the edges
 * that brought us to these nodes are not equivalent, and so the check ends.
 * If the emarks are the same, the edges are equivalent.  We then backtrack and
 * continue the traversal.  If we have exhausted all edges in the subgraph, and
 * have not found any inequivalent nodes, then the subgraphs are equivalent.
 */
static int
equiv_cb(void *bucket, void *arg)
{
        equiv_data_t *ed = arg;
        tdesc_t *mtdp = bucket;
        tdesc_t *ctdp = ed->ed_node;

        ed->ed_clear_mark = ed->ed_cur_mark + 1;
        ed->ed_cur_mark = ed->ed_clear_mark + 1;

        if (equiv_node(ctdp, mtdp, ed)) {
                debug(3, "equiv_node matched %d <%x> %d <%x>\n",
                    ctdp->t_id, ctdp->t_id, mtdp->t_id, mtdp->t_id);
                ed->ed_tgt = mtdp;
                /* matched.  stop looking */
                return (-1);
        }

        return (0);
}

/*ARGSUSED1*/
static int
map_td_tree_pre(tdesc_t *ctdp, tdesc_t **ctdpp __unused, void *private)
{
        merge_cb_data_t *mcd = private;

        if (get_mapping(mcd->md_ta, ctdp->t_id) > 0)
                return (0);

        return (1);
}

/*ARGSUSED1*/
static int
map_td_tree_post(tdesc_t *ctdp, tdesc_t **ctdpp __unused, void *private)
{
        merge_cb_data_t *mcd = private;
        equiv_data_t ed;

        ed.ed_ta = mcd->md_ta;
        ed.ed_clear_mark = mcd->md_parent->td_curemark;
        ed.ed_cur_mark = mcd->md_parent->td_curemark + 1;
        ed.ed_node = ctdp;
        ed.ed_selfuniquify = 0;

        debug(3, "map_td_tree_post on %d <%x> %s\n", ctdp->t_id, ctdp->t_id,tdesc_name(ctdp));

        if (hash_find_iter(mcd->md_parent->td_layouthash, ctdp,
            equiv_cb, &ed) < 0) {
                /* We found an equivalent node */
                if (ed.ed_tgt->t_type == FORWARD && ctdp->t_type != FORWARD) {
                        int id = mcd->md_tgt->td_nextid++;

                        debug(3, "Creating new defn type %d <%x>\n", id, id);
                        add_mapping(mcd->md_ta, ctdp->t_id, id);
                        alist_add(mcd->md_fdida, (void *)(ulong_t)ed.ed_tgt,
                            (void *)(ulong_t)id);
                        hash_add(mcd->md_tdtba, ctdp);
                } else
                        add_mapping(mcd->md_ta, ctdp->t_id, ed.ed_tgt->t_id);

        } else if (debug_level > 1 && hash_iter(mcd->md_parent->td_idhash,
            equiv_cb, &ed) < 0) {
                /*
                 * We didn't find an equivalent node by looking through the
                 * layout hash, but we somehow found it by performing an
                 * exhaustive search through the entire graph.  This usually
                 * means that the "name" hash function is broken.
                 */
                aborterr("Second pass for %d (%s) == %d\n", ctdp->t_id,
                    tdesc_name(ctdp), ed.ed_tgt->t_id);
        } else {
                int id = mcd->md_tgt->td_nextid++;

                debug(3, "Creating new type %d <%x>\n", id, id);
                add_mapping(mcd->md_ta, ctdp->t_id, id);
                hash_add(mcd->md_tdtba, ctdp);
        }

        mcd->md_parent->td_curemark = ed.ed_cur_mark + 1;

        return (1);
}

/*ARGSUSED1*/
static int
map_td_tree_self_post(tdesc_t *ctdp, tdesc_t **ctdpp __unused, void *private)
{
        merge_cb_data_t *mcd = private;
        equiv_data_t ed;

        ed.ed_ta = mcd->md_ta;
        ed.ed_clear_mark = mcd->md_parent->td_curemark;
        ed.ed_cur_mark = mcd->md_parent->td_curemark + 1;
        ed.ed_node = ctdp;
        ed.ed_selfuniquify = 1;
        ed.ed_tgt = NULL;

        if (hash_find_iter(mcd->md_tdtba, ctdp, equiv_cb, &ed) < 0) {
                debug(3, "Self check found %d <%x> in %d <%x>\n", ctdp->t_id,
                    ctdp->t_id, ed.ed_tgt->t_id, ed.ed_tgt->t_id);
                add_mapping(mcd->md_ta, ctdp->t_id,
                    get_mapping(mcd->md_ta, ed.ed_tgt->t_id));
        } else if (debug_level > 1 && hash_iter(mcd->md_tdtba,
            equiv_cb, &ed) < 0) {
                /*
                 * We didn't find an equivalent node using the quick way (going
                 * through the hash normally), but we did find it by iterating
                 * through the entire hash.  This usually means that the hash
                 * function is broken.
                 */
                aborterr("Self-unique second pass for %d <%x> (%s) == %d <%x>\n",
                    ctdp->t_id, ctdp->t_id, tdesc_name(ctdp), ed.ed_tgt->t_id,
                    ed.ed_tgt->t_id);
        } else {
                int id = mcd->md_tgt->td_nextid++;

                debug(3, "Creating new type %d <%x>\n", id, id);
                add_mapping(mcd->md_ta, ctdp->t_id, id);
                hash_add(mcd->md_tdtba, ctdp);
        }

        mcd->md_parent->td_curemark = ed.ed_cur_mark + 1;

        return (1);
}

static tdtrav_cb_f map_pre[] = {
        NULL,
        map_td_tree_pre,        /* intrinsic */
        map_td_tree_pre,        /* pointer */
        map_td_tree_pre,        /* array */
        map_td_tree_pre,        /* function */
        map_td_tree_pre,        /* struct */
        map_td_tree_pre,        /* union */
        map_td_tree_pre,        /* enum */
        map_td_tree_pre,        /* forward */
        map_td_tree_pre,        /* typedef */
        tdtrav_assert,          /* typedef_unres */
        map_td_tree_pre,        /* volatile */
        map_td_tree_pre,        /* const */
        map_td_tree_pre         /* restrict */
};

static tdtrav_cb_f map_post[] = {
        NULL,
        map_td_tree_post,       /* intrinsic */
        map_td_tree_post,       /* pointer */
        map_td_tree_post,       /* array */
        map_td_tree_post,       /* function */
        map_td_tree_post,       /* struct */
        map_td_tree_post,       /* union */
        map_td_tree_post,       /* enum */
        map_td_tree_post,       /* forward */
        map_td_tree_post,       /* typedef */
        tdtrav_assert,          /* typedef_unres */
        map_td_tree_post,       /* volatile */
        map_td_tree_post,       /* const */
        map_td_tree_post        /* restrict */
};

static tdtrav_cb_f map_self_post[] = {
        NULL,
        map_td_tree_self_post,  /* intrinsic */
        map_td_tree_self_post,  /* pointer */
        map_td_tree_self_post,  /* array */
        map_td_tree_self_post,  /* function */
        map_td_tree_self_post,  /* struct */
        map_td_tree_self_post,  /* union */
        map_td_tree_self_post,  /* enum */
        map_td_tree_self_post,  /* forward */
        map_td_tree_self_post,  /* typedef */
        tdtrav_assert,          /* typedef_unres */
        map_td_tree_self_post,  /* volatile */
        map_td_tree_self_post,  /* const */
        map_td_tree_self_post   /* restrict */
};

/*
 * Determining equivalence of iidesc_t nodes
 */

typedef struct iifind_data {
        iidesc_t *iif_template;
        alist_t *iif_ta;
        int iif_newidx;
        int iif_refmerge;
} iifind_data_t;

/*
 * Check to see if this iidesc_t (node) - the current one on the list we're
 * iterating through - matches the target one (iif->iif_template).  Return -1
 * if it matches, to stop the iteration.
 */
static int
iidesc_match(void *data, void *arg)
{
        iidesc_t *node = data;
        iifind_data_t *iif = arg;
        int i;

        if (node->ii_type != iif->iif_template->ii_type ||
            !streq(node->ii_name, iif->iif_template->ii_name) ||
            node->ii_dtype->t_id != iif->iif_newidx)
                return (0);

        if ((node->ii_type == II_SVAR || node->ii_type == II_SFUN) &&
            !streq(node->ii_owner, iif->iif_template->ii_owner))
                return (0);

        if (node->ii_nargs != iif->iif_template->ii_nargs)
                return (0);

        for (i = 0; i < node->ii_nargs; i++) {
                if (get_mapping(iif->iif_ta,
                    iif->iif_template->ii_args[i]->t_id) !=
                    node->ii_args[i]->t_id)
                        return (0);
        }

        if (iif->iif_refmerge) {
                switch (iif->iif_template->ii_type) {
                case II_GFUN:
                case II_SFUN:
                case II_GVAR:
                case II_SVAR:
                        debug(3, "suppressing duping of %d %s from %s\n",
                            iif->iif_template->ii_type,
                            iif->iif_template->ii_name,
                            (iif->iif_template->ii_owner ?
                            iif->iif_template->ii_owner : "NULL"));
                        return (0);
                case II_NOT:
                case II_PSYM:
                case II_SOU:
                case II_TYPE:
                        break;
                }
        }

        return (-1);
}

static int
merge_type_cb(void *data, void *arg)
{
        iidesc_t *sii = data;
        merge_cb_data_t *mcd = arg;
        iifind_data_t iif;
        tdtrav_cb_f *post;

        post = (mcd->md_flags & MCD_F_SELFUNIQUIFY ? map_self_post : map_post);

        /* Map the tdesc nodes */
        (void) iitraverse(sii, &mcd->md_parent->td_curvgen, NULL, map_pre, post,
            mcd);

        /* Map the iidesc nodes */
        iif.iif_template = sii;
        iif.iif_ta = mcd->md_ta;
        iif.iif_newidx = get_mapping(mcd->md_ta, sii->ii_dtype->t_id);
        iif.iif_refmerge = (mcd->md_flags & MCD_F_REFMERGE);

        if (hash_match(mcd->md_parent->td_iihash, sii, iidesc_match,
            &iif) == 1)
                /* successfully mapped */
                return (1);

        debug(3, "tba %s (%d)\n", (sii->ii_name ? sii->ii_name : "(anon)"),
            sii->ii_type);

        list_add(mcd->md_iitba, sii);

        return (0);
}

static int
remap_node(tdesc_t **tgtp, tdesc_t *oldtgt, int selftid, tdesc_t *newself,
    merge_cb_data_t *mcd)
{
        tdesc_t *tgt = NULL;
        tdesc_t template;
        int oldid = oldtgt->t_id;

        if (oldid == selftid) {
                *tgtp = newself;
                return (1);
        }

        if ((template.t_id = get_mapping(mcd->md_ta, oldid)) == 0)
                aborterr("failed to get mapping for tid %d <%x>\n", oldid, oldid);

        if (!hash_find(mcd->md_parent->td_idhash, (void *)&template,
            (void *)&tgt) && (!(mcd->md_flags & MCD_F_REFMERGE) ||
            !hash_find(mcd->md_tgt->td_idhash, (void *)&template,
            (void *)&tgt))) {
                debug(3, "Remap couldn't find %d <%x> (from %d <%x>)\n", template.t_id,
                    template.t_id, oldid, oldid);
                *tgtp = oldtgt;
                list_add(mcd->md_tdtbr, tgtp);
                return (0);
        }

        *tgtp = tgt;
        return (1);
}

static tdesc_t *
conjure_template(tdesc_t *old, int newselfid)
{
        tdesc_t *new = xcalloc(sizeof (tdesc_t));

        new->t_name = old->t_name ? xstrdup(old->t_name) : NULL;
        new->t_type = old->t_type;
        new->t_size = old->t_size;
        new->t_id = newselfid;
        new->t_flags = old->t_flags;

        return (new);
}

/*ARGSUSED2*/
static tdesc_t *
conjure_intrinsic(tdesc_t *old, int newselfid, merge_cb_data_t *mcd __unused)
{
        tdesc_t *new = conjure_template(old, newselfid);

        new->t_intr = xmalloc(sizeof (intr_t));
        bcopy(old->t_intr, new->t_intr, sizeof (intr_t));

        return (new);
}

static tdesc_t *
conjure_plain(tdesc_t *old, int newselfid, merge_cb_data_t *mcd)
{
        tdesc_t *new = conjure_template(old, newselfid);

        (void) remap_node(&new->t_tdesc, old->t_tdesc, old->t_id, new, mcd);

        return (new);
}

static tdesc_t *
conjure_function(tdesc_t *old, int newselfid, merge_cb_data_t *mcd)
{
        tdesc_t *new = conjure_template(old, newselfid);
        fndef_t *nfn = xmalloc(sizeof (fndef_t));
        fndef_t *ofn = old->t_fndef;
        int i;

        (void) remap_node(&nfn->fn_ret, ofn->fn_ret, old->t_id, new, mcd);

        nfn->fn_nargs = ofn->fn_nargs;
        nfn->fn_vargs = ofn->fn_vargs;

        if (nfn->fn_nargs > 0)
                nfn->fn_args = xcalloc(sizeof (tdesc_t *) * ofn->fn_nargs);

        for (i = 0; i < (int) ofn->fn_nargs; i++) {
                (void) remap_node(&nfn->fn_args[i], ofn->fn_args[i], old->t_id,
                    new, mcd);
        }

        new->t_fndef = nfn;

        return (new);
}

static tdesc_t *
conjure_array(tdesc_t *old, int newselfid, merge_cb_data_t *mcd)
{
        tdesc_t *new = conjure_template(old, newselfid);
        ardef_t *nar = xmalloc(sizeof (ardef_t));
        ardef_t *oar = old->t_ardef;

        (void) remap_node(&nar->ad_contents, oar->ad_contents, old->t_id, new,
            mcd);
        (void) remap_node(&nar->ad_idxtype, oar->ad_idxtype, old->t_id, new,
            mcd);

        nar->ad_nelems = oar->ad_nelems;

        new->t_ardef = nar;

        return (new);
}

static tdesc_t *
conjure_su(tdesc_t *old, int newselfid, merge_cb_data_t *mcd)
{
        tdesc_t *new = conjure_template(old, newselfid);
        mlist_t *omem, **nmemp;

        for (omem = old->t_members, nmemp = &new->t_members;
            omem; omem = omem->ml_next, nmemp = &((*nmemp)->ml_next)) {
                *nmemp = xmalloc(sizeof (mlist_t));
                (*nmemp)->ml_offset = omem->ml_offset;
                (*nmemp)->ml_size = omem->ml_size;
                (*nmemp)->ml_name = xstrdup(omem->ml_name ? omem->ml_name : "empty omem->ml_name");
                (void) remap_node(&((*nmemp)->ml_type), omem->ml_type,
                    old->t_id, new, mcd);
        }
        *nmemp = NULL;

        return (new);
}

/*ARGSUSED2*/
static tdesc_t *
conjure_enum(tdesc_t *old, int newselfid, merge_cb_data_t *mcd __unused)
{
        tdesc_t *new = conjure_template(old, newselfid);
        elist_t *oel, **nelp;

        for (oel = old->t_emem, nelp = &new->t_emem;
            oel; oel = oel->el_next, nelp = &((*nelp)->el_next)) {
                *nelp = xmalloc(sizeof (elist_t));
                (*nelp)->el_name = xstrdup(oel->el_name);
                (*nelp)->el_number = oel->el_number;
        }
        *nelp = NULL;

        return (new);
}

/*ARGSUSED2*/
static tdesc_t *
conjure_forward(tdesc_t *old, int newselfid, merge_cb_data_t *mcd)
{
        tdesc_t *new = conjure_template(old, newselfid);

        list_add(&mcd->md_tgt->td_fwdlist, new);

        return (new);
}

/*ARGSUSED*/
static tdesc_t *
conjure_assert(tdesc_t *old __unused, int newselfid __unused, merge_cb_data_t *mcd __unused)
{
        assert(1 == 0);
        return (NULL);
}

static iidesc_t *
conjure_iidesc(iidesc_t *old, merge_cb_data_t *mcd)
{
        iidesc_t *new = iidesc_dup(old);
        int i;

        (void) remap_node(&new->ii_dtype, old->ii_dtype, -1, NULL, mcd);
        for (i = 0; i < new->ii_nargs; i++) {
                (void) remap_node(&new->ii_args[i], old->ii_args[i], -1, NULL,
                    mcd);
        }

        return (new);
}

static int
fwd_redir(tdesc_t *fwd, tdesc_t **fwdp, void *private)
{
        alist_t *map = private;
        void *defn;

        if (!alist_find(map, (void *)fwd, (void **)&defn))
                return (0);

        debug(3, "Redirecting an edge to %s\n", tdesc_name(defn));

        *fwdp = defn;

        return (1);
}

static tdtrav_cb_f fwd_redir_cbs[] = {
        NULL,
        NULL,                   /* intrinsic */
        NULL,                   /* pointer */
        NULL,                   /* array */
        NULL,                   /* function */
        NULL,                   /* struct */
        NULL,                   /* union */
        NULL,                   /* enum */
        fwd_redir,              /* forward */
        NULL,                   /* typedef */
        tdtrav_assert,          /* typedef_unres */
        NULL,                   /* volatile */
        NULL,                   /* const */
        NULL                    /* restrict */
};

typedef struct redir_mstr_data {
        tdata_t *rmd_tgt;
        alist_t *rmd_map;
} redir_mstr_data_t;

static int
redir_mstr_fwd_cb(void *name, void *value, void *arg)
{
        tdesc_t *fwd = name;
        int defnid = (uintptr_t)value;
        redir_mstr_data_t *rmd = arg;
        tdesc_t template;
        tdesc_t *defn;

        template.t_id = defnid;

        if (!hash_find(rmd->rmd_tgt->td_idhash, (void *)&template,
            (void *)&defn)) {
                aborterr("Couldn't unforward %d (%s)\n", defnid,
                    tdesc_name(defn));
        }

        debug(3, "Forward map: resolved %d to %s\n", defnid, tdesc_name(defn));

        alist_add(rmd->rmd_map, (void *)fwd, (void *)defn);

        return (1);
}

static void
redir_mstr_fwds(merge_cb_data_t *mcd)
{
        redir_mstr_data_t rmd;
        alist_t *map = alist_new(NULL, NULL);

        rmd.rmd_tgt = mcd->md_tgt;
        rmd.rmd_map = map;

        if (alist_iter(mcd->md_fdida, redir_mstr_fwd_cb, &rmd)) {
                (void) iitraverse_hash(mcd->md_tgt->td_iihash,
                    &mcd->md_tgt->td_curvgen, fwd_redir_cbs, NULL, NULL, map);
        }

        alist_free(map);
}

static int
add_iitba_cb(void *data, void *private)
{
        merge_cb_data_t *mcd = private;
        iidesc_t *tba = data;
        iidesc_t *new;
        iifind_data_t iif;
        int newidx;

        newidx = get_mapping(mcd->md_ta, tba->ii_dtype->t_id);
        assert(newidx != -1);

        (void) list_remove(mcd->md_iitba, data, NULL, NULL);

        iif.iif_template = tba;
        iif.iif_ta = mcd->md_ta;
        iif.iif_newidx = newidx;
        iif.iif_refmerge = (mcd->md_flags & MCD_F_REFMERGE);

        if (hash_match(mcd->md_parent->td_iihash, tba, iidesc_match,
            &iif) == 1) {
                debug(3, "iidesc_t %s already exists\n",
                    (tba->ii_name ? tba->ii_name : "(anon)"));
                return (1);
        }

        new = conjure_iidesc(tba, mcd);
        hash_add(mcd->md_tgt->td_iihash, new);

        return (1);
}

static int
add_tdesc(tdesc_t *oldtdp, int newid, merge_cb_data_t *mcd)
{
        tdesc_t *newtdp;
        tdesc_t template;

        template.t_id = newid;
        assert(hash_find(mcd->md_parent->td_idhash,
            (void *)&template, NULL) == 0);

        debug(3, "trying to conjure %d %s (%d, <%x>) as %d, <%x>\n",
            oldtdp->t_type, tdesc_name(oldtdp), oldtdp->t_id,
            oldtdp->t_id, newid, newid);

        if ((newtdp = tdesc_ops[oldtdp->t_type].conjure(oldtdp, newid,
            mcd)) == NULL)
                /* couldn't map everything */
                return (0);

        debug(3, "succeeded\n");

        hash_add(mcd->md_tgt->td_idhash, newtdp);
        hash_add(mcd->md_tgt->td_layouthash, newtdp);

        return (1);
}

static int
add_tdtba_cb(void *data, void *arg)
{
        tdesc_t *tdp = data;
        merge_cb_data_t *mcd = arg;
        int newid;
        int rc;

        newid = get_mapping(mcd->md_ta, tdp->t_id);
        assert(newid != -1);

        if ((rc = add_tdesc(tdp, newid, mcd)))
                hash_remove(mcd->md_tdtba, (void *)tdp);

        return (rc);
}

static int
add_tdtbr_cb(void *data, void *arg)
{
        tdesc_t **tdpp = data;
        merge_cb_data_t *mcd = arg;

        debug(3, "Remapping %s (%d)\n", tdesc_name(*tdpp), (*tdpp)->t_id);

        if (!remap_node(tdpp, *tdpp, -1, NULL, mcd))
                return (0);

        (void) list_remove(mcd->md_tdtbr, (void *)tdpp, NULL, NULL);
        return (1);
}

static void
merge_types(hash_t *src, merge_cb_data_t *mcd)
{
        list_t *iitba = NULL;
        list_t *tdtbr = NULL;
        int iirc, tdrc;

        mcd->md_iitba = &iitba;
        mcd->md_tdtba = hash_new(TDATA_LAYOUT_HASH_SIZE, tdesc_layouthash,
            tdesc_layoutcmp);
        mcd->md_tdtbr = &tdtbr;

        (void) hash_iter(src, merge_type_cb, mcd);

        tdrc = hash_iter(mcd->md_tdtba, add_tdtba_cb, mcd);
        debug(3, "add_tdtba_cb added %d items\n", tdrc);

        iirc = list_iter(*mcd->md_iitba, add_iitba_cb, mcd);
        debug(3, "add_iitba_cb added %d items\n", iirc);

        assert(list_count(*mcd->md_iitba) == 0 &&
            hash_count(mcd->md_tdtba) == 0);

        tdrc = list_iter(*mcd->md_tdtbr, add_tdtbr_cb, mcd);
        debug(3, "add_tdtbr_cb added %d items\n", tdrc);

        if (list_count(*mcd->md_tdtbr) != 0)
                aborterr("Couldn't remap all nodes\n");

        /*
         * We now have an alist of master forwards and the ids of the new master
         * definitions for those forwards in mcd->md_fdida.  By this point,
         * we're guaranteed that all of the master definitions referenced in
         * fdida have been added to the master tree.  We now traverse through
         * the master tree, redirecting all edges inbound to forwards that have
         * definitions to those definitions.
         */
        if (mcd->md_parent == mcd->md_tgt) {
                redir_mstr_fwds(mcd);
        }
}

void
merge_into_master(tdata_t *cur, tdata_t *mstr, tdata_t *tgt, int selfuniquify)
{
        merge_cb_data_t mcd;

        cur->td_ref++;
        mstr->td_ref++;
        if (tgt)
                tgt->td_ref++;

        assert(cur->td_ref == 1 && mstr->td_ref == 1 &&
            (tgt == NULL || tgt->td_ref == 1));

        mcd.md_parent = mstr;
        mcd.md_tgt = (tgt ? tgt : mstr);
        mcd.md_ta = alist_new(NULL, NULL);
        mcd.md_fdida = alist_new(NULL, NULL);
        mcd.md_flags = 0;

        if (selfuniquify)
                mcd.md_flags |= MCD_F_SELFUNIQUIFY;
        if (tgt)
                mcd.md_flags |= MCD_F_REFMERGE;

        mstr->td_curvgen = MAX(mstr->td_curvgen, cur->td_curvgen);
        mstr->td_curemark = MAX(mstr->td_curemark, cur->td_curemark);

        merge_types(cur->td_iihash, &mcd);

        if (debug_level >= 3) {
                debug(3, "Type association stats\n");
                alist_stats(mcd.md_ta, 0);
                debug(3, "Layout hash stats\n");
                hash_stats(mcd.md_tgt->td_layouthash, 1);
        }

        alist_free(mcd.md_fdida);
        alist_free(mcd.md_ta);

        cur->td_ref--;
        mstr->td_ref--;
        if (tgt)
                tgt->td_ref--;
}

tdesc_ops_t tdesc_ops[] = {
        { "ERROR! BAD tdesc TYPE", NULL, NULL },
        { "intrinsic",          equiv_intrinsic,        conjure_intrinsic },
        { "pointer",            equiv_plain,            conjure_plain },
        { "array",              equiv_array,            conjure_array },
        { "function",           equiv_function,         conjure_function },
        { "struct",             equiv_su,               conjure_su },
        { "union",              equiv_su,               conjure_su },
        { "enum",               equiv_enum,             conjure_enum },
        { "forward",            NULL,                   conjure_forward },
        { "typedef",            equiv_plain,            conjure_plain },
        { "typedef_unres",      equiv_assert,           conjure_assert },
        { "volatile",           equiv_plain,            conjure_plain },
        { "const",              equiv_plain,            conjure_plain },
        { "restrict",           equiv_plain,            conjure_plain }
};