[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_t.h"
#include "ircons_t.h"
#include "iredges_t.h"
#include "irgmod.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_chordal_arch(ce) ((ce)->session_env->main_env->arch_env)
#define get_reg(irn) arch_get_irn_register(get_chordal_arch(chordal_env), irn, 0)
#define set_reg(irn, reg) arch_set_irn_register(get_chordal_arch(chordal_env), irn, 0, reg)

#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 void clear_link(ir_node *irn, void *data)
{
  set_irn_link(irn, NULL);
}

/**
 * Build a list of phis of a block.
 */
static void collect_phis(ir_node *irn, void *data)
{
  be_chordal_env_t *env = data;
  if(is_Phi(irn) &&
      arch_irn_has_reg_class(env->session_env->main_env->arch_env,
        irn, arch_pos_make_out(0), env->cls)) {

    ir_node *bl = get_nodes_block(irn);
    set_irn_link(irn, get_irn_link(bl));
    set_irn_link(bl, irn);
  }
}

/**
 * Build a ring of phis for each block in the link field.
 * @param env The chordal env.
 */
static INLINE void build_phi_rings(be_chordal_env_t *env)
{
  irg_walk_graph(env->session_env->irg, clear_link, collect_phis, env);
}

static int skip_cf_predicator(const ir_node *irn, void *data) {
  be_chordal_env_t *ce = data;
  arch_env_t *ae = ce->session_env->main_env->arch_env;
  return arch_irn_classify(ae, irn) == arch_irn_class_branch;
}

#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_chordal_env_t *chordal_env, ir_node *phi) {
        int i, max;
        ir_node *arg, *phi_block, *arg_block;
        arch_env_t *arch_env = get_chordal_arch(chordal_env);
  const be_main_session_env_t *session = chordal_env->session_env;
        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(get_chordal_arch(chordal_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);
                // assert(is_Perm(perm));

                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;
        for(other_phi = get_irn_link(phi_block); other_phi; other_phi = get_irn_link(other_phi)) {
          if(other_phi == phi)
            continue;
                                        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_walker(ir_node *bl, void *data)
{
  be_chordal_env_t *ce = data;
  pmap *perm_map = ce->data;
  ir_graph *irg = ce->session_env->irg;
  const be_node_factory_t *fact = ce->session_env->main_env->node_factory;

  /* Dummy targets for the projs */
  ir_node *dummy = new_rd_Unknown(irg, mode_T);

  assert(is_Block(bl));

  /* If the link flag is NULL, this block has no phis. */
  if(get_irn_link(bl)) {
    int i, n;

    /* Look at all predecessors of the phi block */
    for(i = 0, n = get_irn_arity(bl); i < n; ++i) {
      ir_node *pred_bl = get_Block_cfgpred_block(bl, i);
      ir_node *phi, *perm, *insert_after;
      ir_node **in;
      int j, n_projs = 0;
      pmap_entry *ent;
      pmap *arg_map = pmap_create();

      assert(!pmap_contains(perm_map, pred_bl) && "Already permed that block");

      /*
       * Note that all phis in the ring are in the same register class
       * by construction.
       */
      for(phi = get_irn_link(bl); phi; phi = get_irn_link(phi)) {
        ir_node *arg = get_irn_n(phi, i);
        ir_node *proj = pmap_get(arg_map, arg);

        if(!proj) {
          proj = new_r_Proj(irg, pred_bl, dummy, get_irn_mode(arg), n_projs++);
          pmap_insert(arg_map, arg, proj);
        }

        set_irn_n(phi, i, proj);
      }

      j = 0;
      in = malloc(n_projs * sizeof(in[0]));
      pmap_foreach(arg_map, ent)
        in[j++] = ent->key;

      perm = new_Perm(fact, ce->cls, irg, pred_bl, n_projs, in);
      insert_after = sched_skip(sched_last(pred_bl), 0, skip_cf_predicator, ce);
      sched_add_after(insert_after, perm);
      exchange(dummy, perm);

      free(in);
      pmap_destroy(arg_map);

      /* register in perm map */
      pmap_insert(perm_map, pred_bl, perm);
    }
  }
}

static void insert_all_perms(be_chordal_env_t *chordal_env) {
        DBG((dbg, LEVEL_1, "Placing perms...\n"));
  irg_block_walk_graph(chordal_env->session_env->irg, insert_all_perms_walker, NULL, chordal_env);
}

static void     set_regs_or_place_dupls_walker(ir_node *bl, void *data) {
  be_chordal_env_t *chordal_env = data;
  ir_node *phi;

        DBG((dbg, LEVEL_1, "Setting regs and placing dupls...\n"));
  for(phi = get_irn_link(bl); phi; phi = get_irn_link(phi))
    adjust_phi_arguments(chordal_env, phi);
}

static void     set_regs_or_place_dupls(be_chordal_env_t *chordal_env)
{
  irg_block_walk_graph(chordal_env->session_env->irg,
      set_regs_or_place_dupls_walker, NULL, chordal_env);
}


void be_ssa_destruction(be_chordal_env_t *chordal_env) {
        pmap *perm_map = pmap_create();
  ir_graph *irg = chordal_env->session_env->irg;

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

        /* create a map for fast lookup of perms: block --> perm */
        chordal_env->data = perm_map;

  build_phi_rings(chordal_env);
        insert_all_perms(chordal_env);
        dump_ir_block_graph(irg, "-ssa_destr_perms_placed");

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

        pmap_destroy(perm_map);
}

static void ssa_destruction_check_walker(ir_node *bl, void *data)
{
  be_chordal_env_t *chordal_env = data;
  ir_node *phi;
        int i, max;

  for(phi = get_irn_link(bl); phi; phi = get_irn_link(phi)) {
    const arch_register_t *phi_reg, *arg_reg;

    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);
    }
  }
}

void be_ssa_destruction_check(be_chordal_env_t *chordal_env) {
  irg_block_walk_graph(chordal_env->session_env->irg,
      ssa_destruction_check_walker, NULL, chordal_env);
}