[libfirm] / ir / be / bessadestr.c

/**
 * Author:      Daniel Grund
 * Date:                25.05.2005
 * Copyright:   (c) Universitaet Karlsruhe
 * Licence:     This file protected by GPL -  GNU GENERAL PUBLIC LICENSE.
 *
 * Performs SSA-Destruction.
 */
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "debug.h"
#include "set.h"
#include "pmap.h"
#include "irnode.h"
#include "iredges_t.h"
#include "irdump.h"
#include "irprintf.h"

#include "be_t.h"
#include "beutil.h"
#include "bechordal_t.h"
#include "bearch.h"
#include "benode_t.h"
#include "besched_t.h"

static firm_dbg_module_t *dbg = NULL;
#define DEBUG_LVL SET_LEVEL_2


#define get_reg(irn) arch_get_irn_register(chordal_env->arch_env, irn, 0)
#define set_reg(irn, reg) arch_set_irn_register(chordal_env->arch_env, irn, 0, reg)

/**
 * Maps blocks to perm nodes inserted during phi destruction.
 */
typedef struct _block2perm_t {
  ir_node *block, *perm;
} block2perm_t;

static int set_cmp_b2p(const void *x, const void *y, size_t size) {
  const block2perm_t *b1 = x;
  const block2perm_t *b2 = y;
  return b1->block != b2->block;
}

#define is_Branch(irn)          (arch_irn_classify(arch_env, irn) == arch_irn_class_branch)
#define is_Perm(irn)            (arch_irn_classify(arch_env, irn) == arch_irn_class_perm)
#define get_reg_cls(irn)        (arch_get_irn_reg_class(arch_env, irn, arch_pos_make_out(0)))
#define is_curr_reg_class(irn)  (get_reg_cls(p) == chordal_env->cls)

static ir_node *get_or_insert_perm(be_main_session_env_t *session, be_chordal_env_t *chordal_env, ir_node *block) {
        block2perm_t find, *found;
        ir_node *p;
        set *b2p = chordal_env->data;
        const arch_env_t *arch_env = chordal_env->arch_env;


        /* iff needed insert perm node */
        DBG((dbg, LEVEL_1, "    Getting perm in %+F\n", block));

        /* .if the perm is in the pset return it */
        find.block = block;
        find.perm = NULL;
        found = set_insert(b2p, &find, sizeof(find), HASH_PTR(find.block));
        if (found->perm) {
                DBG((dbg, LEVEL_1, "      found it %+F in map\n", found->perm));
                return found->perm;
        }

        /* .else look for a perm of right register class in the schedule */
        p = sched_last(find.block);
        while (!is_Block(p) && (is_Branch(p) || (is_Perm(p) && !is_curr_reg_class(p))))
                p = sched_prev(p);

        /* if we haven't found a perm of the right register class create a new one */
        if (! (is_Perm(p) && is_curr_reg_class(p))) {
                DBG((dbg, LEVEL_1, "      insert it after %+F\n", p));
                p = insert_Perm_after(session, chordal_env->cls, p);
        }

        /* insert perm into pset and return it*/
        found->perm = p;
        return p;
}

#define is_pinned(irn) (get_irn_link(irn))
#define get_pinning_block(irn) ((ir_node *)get_irn_link(irn))
#define pin_irn(irn, lock) (set_irn_link(irn, lock))

/**
 * Adjusts the register allocation for the phi-operands
 * by inserting perm nodes, if necessary.
 * @param phi The phi node to adjust operands for
 */
static void adjust_phi_arguments(be_main_session_env_t *session, be_chordal_env_t *chordal_env, ir_node *phi) {
        int i, max;
        ir_node *arg, *phi_block, *arg_block;
        const arch_register_t *phi_reg, *arg_reg;
        const arch_register_class_t *cls;

        assert(is_Phi(phi) && "Can only handle phi-destruction :)");
        DBG((dbg, LEVEL_1, "  for %+F\n", phi));

        cls = arch_get_irn_reg_class(session->main_env->arch_env, phi, arch_pos_make_out(0));
        phi_block = get_nodes_block(phi);
        phi_reg = get_reg(phi);

        /* process all arguments of the phi */
        for(i=0, max=get_irn_arity(phi); i<max; ++i) {
                ir_node *perm;

                arg = get_irn_n(phi, i);
                arg_block = get_nodes_block(arg);
                arg_reg = get_reg(arg);
                perm = get_Proj_pred(arg);

                DBG((dbg, LEVEL_1, "    arg %+F has perm %+F\n", arg, perm));
                /* if registers don't match ...*/
                if (phi_reg != arg_reg) {
                        DBG((dbg, LEVEL_1, "      regs don't match %d %d\n", phi_reg, arg_reg));

                        /* First check if there is another phi in the same block
                         * having arg at the same pos in its arg-list and the same color as arg */
                        if (!is_pinned(arg)) {
                                DBG((dbg, LEVEL_1, "      arg is not pinned\n"));
                                ir_node *other_phi = phi;
                                while ((other_phi = get_irn_link(other_phi)) != phi) {
                                        assert(is_Phi(other_phi) && get_nodes_block(phi) == get_nodes_block(other_phi) && "link fields are screwed up");
                                        if (get_irn_n(other_phi, i) == arg && get_reg(other_phi) == arg_reg) {
                                                DBG((dbg, LEVEL_1, "      other phi pinned the argument\n"));
                                                pin_irn(arg, phi_block);
                                        }
                                }
                        }

                        /* If arg is pinned, another phi set the color of arg and pinned it.
                         * So this phi can't change the color again and a duplicate must be inserted.
                         *
                         * If arg interferes with phi, one can never set the same color for both
                         * Hence, a duplicate must be inserted */
                        if (is_pinned(arg) || nodes_interfere(chordal_env, phi, arg)) {
                                ir_node *dupl, *tmp;
                                assert(get_pinning_block(arg) == phi_block && "If arg is pinned it must be due to a phi in the same block");

                                dupl = new_Copy(session->main_env->node_factory, cls, session->irg, arg_block, arg);
                                set_irn_n(phi, i, dupl);
                                set_reg(dupl, phi_reg);
                                DBG((dbg, LEVEL_1, "      inserting dupl %+F\n", dupl));

                                /* Add dupl to schedule */
                                tmp = sched_next(perm);
                                while (is_Proj(tmp) && sched_has_next(tmp))
                                        tmp = sched_next(tmp);
                                sched_add_after(tmp, dupl);

                                /* Add dupl to chained list of duplicates. Ptrs starting at the Perm */
                                tmp = perm;
                                while (get_irn_link(tmp))
                                        tmp = get_irn_link(tmp);
                                set_irn_link(tmp, dupl);
                                set_irn_link(dupl, NULL);

                                /* now the arg is the dupl */
                                arg = dupl;
                        } else {
                                /* Arg is not pinned. So set its color to the color of the phi.
                                 * If the phi color is used by another proj of this perm
                                 * one must NOT swap the colors. Proof: Critical edges removed,
                                 * livein(PhiBl) = liveout(ArgBl), if all phis are processed then
                                 * every color is used exactly once.
                                 */
                                DBG((dbg, LEVEL_1, "      just set color\n"));
                                set_reg(arg, phi_reg);
                        }
                }

                /* Now the color of the arg (arg may be a dupl now) and the phi-result are equal.
                 * Pin it, so everyone knows and it never gets changed again.
                 * An arg never is a phi, because perms were inserted. So the link field is free */
                DBG((dbg, LEVEL_1, "      arg has correct color (now), so pin it\n"));
                pin_irn(arg, phi_block);
        }
}


static void insert_all_perms(be_main_session_env_t *session, be_chordal_env_t *chordal_env) {
        pmap_entry *pme;
        int i, max;
        ir_node *first_phi, *recent_phi;

        DBG((dbg, LEVEL_1, "Placing perms...\n"));

        /* place perms in cf-preds of phis */
        pmap_foreach(chordal_env->border_heads, pme) {
                border_t *curr;
                struct list_head *head = pme->value;

                first_phi = NULL;
                /* iterate over the first ops in the block until a non-phi is reached */
                list_for_each_entry(border_t, curr, head, list) {
                        ir_node *phi = curr->irn;

                        if (curr->is_def && curr->is_real && is_Phi(phi)) {
                                set_irn_link(phi, NULL);
                                /* chain of phis in a block */
                                if (first_phi == NULL)
                                        first_phi = phi;
                                else
                                        set_irn_link(recent_phi, phi);
                                recent_phi = phi;

                                /* insert perms */
                                DBG((dbg, LEVEL_1, "  for %+F\n", phi));
                                for(i=0, max=get_irn_arity(phi); i<max; ++i) {
                                        ir_node *perm;

                                        perm = get_or_insert_perm(session, chordal_env, get_Block_cfgpred_block(get_nodes_block(phi), i));
                                        DBG((dbg, LEVEL_1, "    %+F in block %N\n", perm, get_Block_cfgpred_block(get_nodes_block(phi), i)));
                                        set_irn_link(perm, NULL);
                                }
                        }
                }
                if (first_phi)
                        set_irn_link(recent_phi, first_phi);
        }
}

static void     set_regs_or_place_dupls(be_main_session_env_t *session, be_chordal_env_t *chordal_env) {
        pmap_entry *pme;

        DBG((dbg, LEVEL_1, "Setting regs and placing dupls...\n"));

        /* iterate over all blocks and correct color of arguments*/
        pmap_foreach(chordal_env->border_heads, pme) {
                border_t *curr;
                struct list_head *head = pme->value;

                /* iterate over the first ops in the block until a non-phi is reached */
                list_for_each_entry(border_t, curr, head, list)
                        if (curr->is_def && curr->is_real && is_Phi(curr->irn))
                                adjust_phi_arguments(session, chordal_env, curr->irn);
        }
}

void be_ssa_destruction(be_main_session_env_t *session, be_chordal_env_t *chordal_env) {
        set *b2p;

        dbg = firm_dbg_register("ir.be.ssadestr");
        firm_dbg_set_mask(dbg, DEBUG_LVL);

        /* create a map for fast lookup of perms: block --> perm */
        b2p = new_set(set_cmp_b2p, 32);
        chordal_env->data = b2p;

        insert_all_perms(session, chordal_env);
        dump_ir_block_graph(session->irg, "-ssa_destr_perms_placed");

        set_regs_or_place_dupls(session, chordal_env);
        dump_ir_block_graph(session->irg, "-ssa_destr_regs_set");

        del_set(b2p);
}

void be_ssa_destruction_check(be_main_session_env_t *session, be_chordal_env_t *chordal_env) {
        pmap_entry *pme;
        int i, max;

        /* iterate over all blocks */
        pmap_foreach(chordal_env->border_heads, pme) {
                border_t *curr;
                struct list_head *head = pme->value;

                /* iterate over the first ops in the block */
                list_for_each_entry(border_t, curr, head, list)
                        if (curr->is_def && curr->is_real && is_Phi(curr->irn)) {
                                const arch_register_t *phi_reg, *arg_reg;
                                ir_node *phi = curr->irn;

                                phi_reg = get_reg(phi);
                                /* iterate over all args of phi */
                                for(i=0, max=get_irn_arity(phi); i<max; ++i) {
                                        ir_node *arg = get_irn_n(phi, i);
                                        arg_reg = get_reg(arg);
                                        if(phi_reg != arg_reg) {
                                                ir_printf("Registers of %+F and %+F differ: %s %s\n", phi, arg, phi_reg->name, arg_reg->name);
                                                assert(0 && "Registers of phi and arg differ\n");
                                        }
                                        if(!is_pinned(arg))
                                                ir_printf("Warning: Arg %+F not pinned\n", arg);
                                }
                        }
        }
}