dead node elimination now handles all anchors equaly

[libfirm] / ir / ir / iredges.c

/**
 * Always available outs.
 * @author Sebastian Hack
 * @date 14.1.2005
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#ifdef HAVE_ALLOCA_H
#include <alloca.h>
#endif
#ifdef HAVE_MALLOC_H
#include <malloc.h>
#endif

#include "irnode_t.h"
#include "iredges_t.h"
#include "irgwalk.h"
#include "irdump_t.h"
#include "irprintf.h"
#include "irhooks.h"
#include "debug.h"
#include "set.h"

DEBUG_ONLY(static firm_dbg_module_t *dbg;)

#if FIRM_EDGES_INPLACE

/**
 * This flag is set to 1, if the edges get initialized for an irg.
 * Then register additional data is forbidden.
 */
static int edges_used = 0;

static int edges_private_size = 0;

int edges_register_private_data(size_t n)
{
        int res = edges_private_size;

        assert(!edges_used && "you cannot register private edge data, if edges have been initialized");

        edges_private_size += n;
        return res;
}

#define TIMES37(x) (((x) << 5) + ((x) << 2) + (x))

#define get_irn_out_list_head(irn) (&get_irn_out_info(irn)->outs)

static int edge_cmp(const void *p1, const void *p2, size_t len)
{
        const ir_edge_t *e1 = p1;
        const ir_edge_t *e2 = p2;
        int res = e1->src == e2->src && e1->pos == e2->pos;

        return !res;
}

#define edge_hash(edge) (TIMES37((edge)->pos) + HASH_PTR((edge)->src))

/**
 * Initialize the out information for a graph.
 * @note Dead node elim can call this on an already initialized graph.
 */
void edges_init_graph(ir_graph *irg)
{
        if(edges_activated(irg)) {
                irg_edge_info_t *info = _get_irg_edge_info(irg);
                int amount = 2048;

                edges_used = 1;

                if(info->edges) {
                        amount = set_count(info->edges);
                        del_set(info->edges);
                }

                info->edges = new_set(edge_cmp, amount);
        }
}

#define EDGE_SIZE(src) \
    (edges_private_size + (is_Block(src) ? sizeof(ir_block_edge_t) : sizeof(ir_edge_t)))


/**
 * Get the edge object of an outgoing edge at a node.
 * @param   irg The graph, the node is in.
 * @param   src The node at which the edge originates.
 * @param   pos The position of the edge.
 * @return      The corresponding edge object or NULL,
 *              if no such edge exists.
 */
const ir_edge_t *get_irn_edge(ir_graph *irg, const ir_node *src, int pos)
{
        if(edges_activated(irg)) {
                irg_edge_info_t *info = _get_irg_edge_info(irg);
                size_t size           = EDGE_SIZE(src);
                ir_edge_t key;

                key.src = (ir_node *) src;
                key.pos = pos;
                return set_find(info->edges, &key, size, edge_hash(&key));
        }

        return NULL;
}

/**
 * Change the out count
 */
static INLINE void edge_change_cnt(ir_node *tgt, int ofs) {
        irn_edge_info_t *info = _get_irn_edge_info(tgt);
        info->out_count += ofs;
}

/* The edge from (src, pos) -> old_tgt is redirected to tgt */
void edges_notify_edge(ir_node *src, int pos, ir_node *tgt, ir_node *old_tgt, ir_graph *irg)
{
        const char *msg = "";

        if(!edges_activated(irg))
                return;

#if 0
        assert(node_is_in_irgs_storage(irg, src) && "source not in irg");
#endif

        /*
         * Only do something, if the old and new target differ.
         */
        if(tgt != old_tgt) {
                int is_block_edge = is_Block(src);
                set *edges = _get_irg_edge_info(irg)->edges;
                ir_edge_t *edge;

                /*
                 * This is scary, but:
                 * If two entries in a set do not have the same size, they are
                 * treated as unequal, ignoring the comparison function.
                 * So, edges from blocks have extra storage (they are
                 * ir_block_edge_t's).
                 *
                 * Also add the amount of registered private data to the
                 * size of the edge.
                 */
                size_t size      = EDGE_SIZE(src);
                ir_edge_t *templ = alloca(size);

                /* Initialize the edge template to search in the set. */
                memset(templ, 0, size);
                templ->src = src;
                templ->pos = pos;
                templ->invalid = 0;
                templ->present = 0;
                DEBUG_ONLY(templ->src_nr = get_irn_node_nr(src));

                /*
                 * If the target is NULL, the edge shall be deleted.
                 */
                if (tgt == NULL) {
                        /* search the edge in the set. */
                        edge = set_find(edges, templ, size, edge_hash(templ));

                        /* mark the edge invalid if it was found */
                        if(edge) {
                                ir_block_edge_t *block_edge = (ir_block_edge_t *) edge;

                                msg = "deleting";
                                list_del(&edge->list);
                                edge->invalid = 1;
                                edge->pos = -2;
                                edge->src = NULL;

                                /*
                                 * If the edge is a cf edge, we delete it also
                                 * from the list of all block successor edges.
                                 */
                                if(is_block_edge) {
                                        list_del(&block_edge->succ_list);
                                        edge_change_cnt(old_tgt,  -1);
                                }
                        }

                        /* If the edge was not found issue a warning on the debug stream */
                        else {
                                msg = "edge to delete not found!\n";
                        }
                } /* if */

                /*
                 * The target is not NULL and the old target differs
                 * from the new target, the edge shall be moved (if the
                 * old target was != NULL) or added (if the old target was
                 * NULL).
                 */
                else {
                        struct list_head *head = _get_irn_outs_head(tgt);

                        /*
                         * The list head in the block of the edges target.
                         * Therein all control flow edges directed at that block
                         * are recorded.
                         */
                        struct list_head *succ_head =
                                is_block_edge ? _get_block_succ_head(get_nodes_block(tgt)) : NULL;

                        ir_block_edge_t *block_edge;

#if 0
                        if(!node_is_in_irgs_storage(irg, tgt))
                                return;
#endif
                        assert(head->next && head->prev &&
                                        "target list head must have been initialized");

                        /*
                         * insert the edge, if it is not yet in the set or return
                         * the instance in the set.
                         */
                        edge = set_insert(edges, templ, size, edge_hash(templ));
                        block_edge = (ir_block_edge_t *) edge;

#ifdef DEBUG_libfirm
                        assert(!edge->invalid && "Invalid edge encountered");
#endif

                        /* If the old target is not null, the edge is moved. */
                        if(old_tgt) {
                                msg = "redirecting";
                                list_move(&edge->list, head);

                                /* If the edge is a cf edge, move it from the successor list. */
                                if(is_block_edge)
                                        list_move(&block_edge->succ_list, succ_head);

                                edge_change_cnt(old_tgt,  -1);
                        }

                        /* The old target was null, thus, the edge is newly created. */
                        else {
                                msg = "adding";
                                list_add(&edge->list, head);

                                /*
                                 * If the edge is cf edge, enter it into the successor list
                                 * of the target node's block.
                                 */
                                if(is_block_edge)
                                        list_add(&block_edge->succ_list, succ_head);
                        }

                        edge_change_cnt(tgt,  +1);
                } /* else */
        }

        /* If the target and the old target are equal, nothing is done. */
        DBG((dbg, LEVEL_5, "announce out edge: %n[%p] %d-> %n[%p](%n[%p]): %s\n",
                                src, src, pos, tgt, tgt, old_tgt, old_tgt, msg));
}

void edges_node_deleted(ir_node *old, ir_graph *irg)
{
        if(edges_activated(irg)) {
                int not_a_block = !is_Block(old);
                int i, n;

                DBG((dbg, LEVEL_5, "node deleted: %n\n", old));

                /* Change to get_irn_n */
                for(i = -not_a_block, n = get_irn_arity(old); i < n; ++i) {
                        ir_node *old_tgt = get_irn_n(old, i);
                        DBG((dbg, LEVEL_5, "\tdelete to old target %n\n", old_tgt));
                        edges_notify_edge(old, i, NULL, old_tgt, irg);
                }

        }
}

void edges_invalidate(ir_node *irn, ir_graph *irg)
{
        edges_node_deleted(irn, irg);
}

/**
 * Post-Walker: notify all edges
 */
static void build_edges_walker(ir_node *irn, void *data)
{
        ir_graph *irg = data;
        int not_a_block = !is_Block(irn);
        int i, n;

        for(i = -not_a_block, n = get_irn_arity(irn); i < n; ++i)
                edges_notify_edge(irn, i, get_irn_n(irn, i), NULL, irg);
}

/**
 * Pre-Walker: initializes the list-heads and set the out-count
 * of all nodes to 0.
 */
static void init_lh_walker(ir_node *irn, void *data)
{
        INIT_LIST_HEAD(_get_irn_outs_head(irn));
        if(is_Block(irn))
                INIT_LIST_HEAD(_get_block_succ_head(irn));
        _get_irn_edge_info(irn)->out_count = 0;
}

void edges_activate(ir_graph *irg)
{
        irg_edge_info_t *info = _get_irg_edge_info(irg);

        info->activated = 1;
        edges_init_graph(irg);
        irg_walk_graph(irg, init_lh_walker, build_edges_walker, irg);
}

void edges_deactivate(ir_graph *irg)
{
        irg_edge_info_t *info = _get_irg_edge_info(irg);

        info->activated = 0;
        if(info->edges) {
                del_set(info->edges);
    info->edges = NULL;
  }
}

int (edges_activated)(const ir_graph *irg)
{
        return _edges_activated(irg);
}


/**
 * Reroute all use-edges from a node to another.
 * @param from The node whose use-edges shall be withdrawn.
 * @param to The node to which all the use-edges of @p from shall be
 * sent to.
 */
void edges_reroute(ir_node *from, ir_node *to, ir_graph *irg)
{
        if(edges_activated(irg)) {
                struct list_head *head = _get_irn_outs_head(from);

                DBG((dbg, LEVEL_5,
                                        "reroute from %n to %n\n", from, to));

                while(head != head->next) {
                        ir_edge_t *edge = list_entry(head->next, ir_edge_t, list);
                        // DBG((dbg, LEVEL_5, "\t%n %d\n", edge->src, edge->pos));
                        assert(edge->pos >= -1);
                        set_irn_n(edge->src, edge->pos, to);
                }
        }
}

static void verify_set_presence(ir_node *irn, void *data)
{
        ir_graph *irg = data;
        set *edges = _get_irg_edge_info(irg)->edges;
        int not_a_block = !is_Block(irn);
        int i, n;

        for(i = 0, n = get_irn_arity(irn) + not_a_block; i < n; ++i) {
                ir_block_edge_t space;
                ir_edge_t *templ = (ir_edge_t *) &space;
                ir_edge_t *e;
                size_t size = not_a_block ? sizeof(ir_edge_t) : sizeof(ir_block_edge_t);

                templ->src = irn;
                templ->pos = i - not_a_block;

                e = set_find(edges, templ, size, edge_hash(templ));
                if(e != NULL)
                        e->present = 1;
                else
                        DBG((dbg, LEVEL_DEFAULT, "edge %n,%d is missing\n", irn, templ->pos));
        }
}

static void verify_list_presence(ir_node *irn, void *data)
{
        const ir_edge_t *e;

        foreach_out_edge(irn, e) {
                ir_node *tgt = get_irn_n(e->src, e->pos);
                if(irn != tgt)
                        DBG((dbg, LEVEL_DEFAULT, "edge %n,%d is no out edge of %n but of %n\n",
                                        e->src, e->pos, irn, tgt));
        }

}

void edges_verify(ir_graph *irg)
{
        set *edges = _get_irg_edge_info(irg)->edges;
        ir_edge_t *e;

        /* Clear the present bit in all edges available. */
        for(e = set_first(edges); e; e = set_next(edges))
                e->present = 0;

        irg_walk_graph(irg, verify_set_presence, verify_list_presence, irg);

        /*
         * Dump all edges which are not invalid and not present.
         * These edges are superfluous and their presence in the
         * edge set is wrong.
         */
        for(e = set_first(edges); e; e = set_next(edges)) {
                if(!e->invalid && !e->present)
                        DBG((dbg, LEVEL_DEFAULT, "edge %n,%d is superfluous\n", e->src, e->pos));
        }
}

void init_edges(void)
{
        FIRM_DBG_REGISTER(dbg, DBG_EDGES);
        /* firm_dbg_set_mask(dbg, -1); */
}


const ir_edge_t *(get_irn_out_edge_first)(const ir_node *irn)
{
        return _get_irn_out_edge_first(irn);
}

const ir_edge_t *(get_irn_out_edge_next)(const ir_node *irn, const ir_edge_t *last)
{
        return _get_irn_out_edge_next(irn, last);
}

ir_node *(get_edge_src_irn)(const ir_edge_t *edge)
{
        return _get_edge_src_irn(edge);
}

int (get_edge_src_pos)(const ir_edge_t *edge)
{
        return _get_edge_src_pos(edge);
}

int (get_irn_n_edges)(const ir_node *irn)
{
        return _get_irn_n_edges(irn);
}


#endif /* FIRM_EDGES_INPLACE */