[libfirm] / ir / be / becopyopt.c

/**
 * Author:      Daniel Grund
 * Date:                12.04.2005
 * Copyright:   (c) Universitaet Karlsruhe
 * Licence:     This file protected by GPL -  GNU GENERAL PUBLIC LICENSE.
 */
#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 "irprog.h"
#include "irloop_t.h"

#include "xmalloc.h"
#include "bechordal_t.h"
#include "becopyopt.h"
#include "becopystat.h"

static firm_dbg_module_t *dbg = NULL;

#define is_curr_reg_class(irn) (arch_get_irn_reg_class(co->chordal_env->arch_env, irn, arch_pos_make_out(0)) == co->chordal_env->cls)

#define MIN(a,b) ((a<b)?(a):(b))
#define MAX(a,b) ((a<b)?(b):(a))

/**
 * Computes the weight of a 'max independent set' wrt. ifg-edges only
 * (no coloring conflicts, no register constraints)
 * @return The costs of such a mis
 * NOTE: Code adapted from becopyheur
 * BETTER: Here we can be sure having a chordal graph to work on,
 *                 so, for 'larger' opt-units we could use a special algorithm.
 */
static int ou_max_ind_set_costs(unit_t *ou) {
        ir_node **irns;
        int max, pos, curr_weight, best_weight = 0;
        bitset_t *curr;

        irns = alloca((ou->node_count-1) * sizeof(*irns));
        curr = bitset_alloca(ou->node_count-1);

        /* brute force the best set */
        bitset_set_all(curr);
        while ((max = bitset_popcnt(curr)) != 0) {
                /* check if curr is a stable set */
                int i, o, is_stable_set = 1;

                /* copy the irns */
                i = 0;
                bitset_foreach(curr, pos)
                        irns[i++] = ou->nodes[1+pos];
                assert(i==max);

                for(i=0; i<max; ++i)
                        for(o=i+1; o<max; ++o) /* !!!!! difference to qnode_max_ind_set(): NOT o=i */
                                if (nodes_interfere(ou->co->chordal_env, irns[i], irns[o])) {
                                        is_stable_set = 0;
                                        break;
                                }

                if (is_stable_set) {
                        /* calc current weigth */
                        curr_weight = 0;
                        bitset_foreach(curr, pos)
                                curr_weight += ou->costs[1+pos];

                        /* any better ? */
                        if (curr_weight > best_weight)
                                best_weight = curr_weight;
                }

                bitset_minus1(curr);
        }
        return best_weight;
}

/**
 * Builds an optimization unit for a given optimizable irn (root).
 * This opt-unit is inserted in the main structure co.
 * If an arg of root itself is optimizable process this arg before with a
 * recursive call. For handling this situation and loops co->root is used
 * to remember all roots.
 */
static void co_append_unit(copy_opt_t *co, ir_node *root) {
        int i, arity;
        unit_t *unit;
        struct list_head *tmp;

        DBG((dbg, LEVEL_1, "\t  Root: %n %N\n", root, root));
        /* check if we encountered this root earlier */
        if (pset_find_ptr(co->roots, root))
                return;
        pset_insert_ptr(co->roots, root);

        assert(is_curr_reg_class(root) && "node is in wrong register class!");

        /* init unit */
        arity = get_irn_arity(root);
        unit = xcalloc(1, sizeof(*unit));
        unit->co = co;
        unit->nodes = xmalloc((arity+1) * sizeof(*unit->nodes));
        unit->costs = xmalloc((arity+1) * sizeof(*unit->costs));
        unit->node_count = 1;
        unit->nodes[0] = root;
        INIT_LIST_HEAD(&unit->queue);

        /* check all args */
        if (is_Phi(root)) {
                for (i=0; i<arity; ++i) {
                        int o, arg_pos = 0;
                        ir_node *arg = get_irn_n(root, i);

                        assert(is_curr_reg_class(arg) && "Argument not in same register class.");
                        if (arg == root)
                                continue;
                        if (nodes_interfere(co->chordal_env, root, arg)) {
                                unit->inevitable_costs += co->get_costs(root, arg, i);
                                continue;
                        }

                        /* Else insert the argument of the phi to the members of this ou */
                        DBG((dbg, LEVEL_1, "\t   Member: %n %N\n", arg, arg));

                        /* Check if arg has occurred at a prior position in the arg/list */
                        for (o=0; o<unit->node_count; ++o)
                                if (unit->nodes[o] == arg) {
                                        arg_pos = o;
                                        break;
                                }

                        if (!arg_pos) { /* a new argument */
                                /* insert node, set costs */
                                unit->nodes[unit->node_count] = arg;
                                unit->costs[unit->node_count] = co->get_costs(root, arg, i);
                                unit->node_count++;
                        } else { /* arg has occured before in same phi */
                                /* increase costs for existing arg */
                                unit->costs[arg_pos] += co->get_costs(root, arg, i);
                        }
                }
                unit->nodes = xrealloc(unit->nodes, unit->node_count * sizeof(*unit->nodes));
                unit->costs = xrealloc(unit->costs, unit->node_count * sizeof(*unit->costs));
        } else if (is_Copy(co->chordal_env->arch_env, root)) {
                assert(!nodes_interfere(co->chordal_env, root, get_Copy_src(root)));
                unit->nodes[1] = get_Copy_src(root);
                unit->costs[1] = co->get_costs(root, unit->nodes[1], -1);
                unit->node_count = 2;
                unit->nodes = xrealloc(unit->nodes, 2 * sizeof(*unit->nodes));
                unit->costs = xrealloc(unit->costs, 2 * sizeof(*unit->costs));
        } else
                assert(0 && "This is not an optimizable node!");
        /* TODO add ou's for 2-addr-code instructions */


        /* Determine the maximum costs this unit can cause: all_nodes_cost */
        for(i=1; i<unit->node_count; ++i) {
                unit->sort_key = MAX(unit->sort_key, unit->costs[i]);
                unit->all_nodes_costs += unit->costs[i];
        }

        /* Determine the minimal costs this unit will cause: min_nodes_costs */
        unit->min_nodes_costs += unit->all_nodes_costs - ou_max_ind_set_costs(unit);

        /* Insert the new ou according to its sort_key */
        tmp = &co->units;
        while (tmp->next != &co->units && list_entry_units(tmp->next)->sort_key > unit->sort_key)
                tmp = tmp->next;
        list_add(&unit->units, tmp);
}

static void co_collect_in_block(ir_node *block, void *env) {
        copy_opt_t *co = env;
        struct list_head *head = get_block_border_head(co->chordal_env, block);
        border_t *curr;

        list_for_each_entry_reverse(border_t, curr, head, list)
                if (curr->is_def && curr->is_real && is_optimizable(co->chordal_env->arch_env, curr->irn))
                        co_append_unit(co, curr->irn);
}

static void co_collect_units(copy_opt_t *co) {
        DBG((dbg, LEVEL_1, "\tCollecting optimization units\n"));
        co->roots = pset_new_ptr(64);
        dom_tree_walk_irg(co->chordal_env->irg, co_collect_in_block, NULL, co);
        del_pset(co->roots);
}

copy_opt_t *new_copy_opt(be_chordal_env_t *chordal_env, int (*get_costs)(ir_node*, ir_node*, int)) {
        const char *s1, *s2, *s3;
        int len;
        copy_opt_t *co;

        dbg = firm_dbg_register("ir.be.copyopt");
        firm_dbg_set_mask(dbg, DEBUG_LVL_CO);

        co = xcalloc(1, sizeof(*co));
        co->chordal_env = chordal_env;
        co->get_costs = get_costs;

        s1 = get_irp_prog_name();
        s2 = get_entity_name(get_irg_entity(co->chordal_env->irg));
        s3 = chordal_env->cls->name;
        len = strlen(s1) + strlen(s2) + strlen(s3) + 5;
        co->name = xmalloc(len);
        snprintf(co->name, len, "%s__%s__%s", s1, s2, s3);
        if (!strcmp(co->name, DEBUG_IRG))
                firm_dbg_set_mask(dbg, DEBUG_IRG_LVL_CO);
        else
                firm_dbg_set_mask(dbg, DEBUG_LVL_CO);

        INIT_LIST_HEAD(&co->units);
        co_collect_units(co);
        return co;
}

void free_copy_opt(copy_opt_t *co) {
        unit_t *curr, *tmp;
        xfree(co->name);
        list_for_each_entry_safe(unit_t, curr, tmp, &co->units, units) {
                xfree(curr->nodes);
                xfree(curr);
        }
}

int is_optimizable_arg(const copy_opt_t *co, ir_node *irn) {
        int i, max;
        for(i=0, max=get_irn_n_outs(irn); i<max; ++i) {
                ir_node *n = get_irn_out(irn, i);
                if ((is_Phi(n) || is_Perm(co->chordal_env->arch_env, n)) && (irn == n || !nodes_interfere(co->chordal_env, irn, n)))
                        return 1;
        }
        return 0;
}

int get_costs_loop_depth(ir_node *root, ir_node* arg, int pos) {
        int cost = 0;
        ir_loop *loop;
        ir_node *root_block = get_nodes_block(root);

        assert(pos==-1 || is_Phi(root));
        if (pos == -1) {
                /* a perm places the copy in the same block as it resides */
                loop = get_irn_loop(root_block);
        } else {
                /* for phis the copies are placed in the corresponding pred-block */
                loop = get_irn_loop(get_Block_cfgpred_block(root_block, pos));
        }
        if (loop)
                cost = 2*get_loop_depth(loop);
        return cost+1;
}

int get_costs_all_one(ir_node *root, ir_node* arg, int pos) {
        return 1;
}

int co_get_copy_costs(const copy_opt_t *co) {
        int i, res = 0;
        unit_t *curr;

        list_for_each_entry(unit_t, curr, &co->units, units) {
                int root_col = get_irn_col(co, curr->nodes[0]);
                res += curr->inevitable_costs;
                DBG((dbg, LEVEL_1, "  Adding costs for root %+F color %d\n", curr->nodes[0], root_col));
                for (i=1; i<curr->node_count; ++i) {
                        int arg_col = get_irn_col(co, curr->nodes[i]);
                        if (root_col != arg_col) {
                                DBG((dbg, LEVEL_1, "  Arg %+F color %d costs %d\n", curr->nodes[i], arg_col, curr->costs[i]));
                                res += curr->costs[i];
                        }
                }
        }
        return res;
}

int co_get_lower_bound(const copy_opt_t *co) {
        int res = 0;
        unit_t *curr;
        list_for_each_entry(unit_t, curr, &co->units, units)
                res += curr->inevitable_costs + curr->min_nodes_costs;
        return res;
}