[libfirm] / ir / be / bechordal.c

/**
 * Chordal register allocation.
 * @author Sebastian Hack
 * @date 8.12.2004
 *
 * Copyright (C) Universitaet Karlsruhe
 * Released under the GPL
 */

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

#include <ctype.h>

#include "obst.h"
#include "list.h"
#include "bitset.h"
#include "iterator.h"

#include "irmode_t.h"
#include "irgraph_t.h"
#include "irprintf_t.h"
#include "irgwalk.h"
#include "irdump.h"
#include "irdom.h"
#include "debug.h"
#include "xmalloc.h"

#include "beutil.h"
#include "besched.h"
#include "bera_t.h"
#include "benumb_t.h"
#include "besched_t.h"
#include "belive_t.h"
#include "bechordal_t.h"
#include "bearch.h"

#define BUILD_GRAPH
#undef DUMP_INTERVALS
#undef DUMP_PRESSURE
#undef DUMP_IFG

#if defined(DUMP_IFG) && !defined(BUILD_GRAPH)
#define BUILD_GRAPH
#endif


#ifdef DEBUG_libfirm
#include "fourcc.h"

/* Make a fourcc for border checking. */
#define BORDER_FOURCC                           FOURCC('B', 'O', 'R', 'D')

#endif /* DEBUG_libfirm */

#define TEST_COLORS 2048

static firm_dbg_module_t *dbg;

/**
 * Environment for each of the chordal register allocator phases
 */
typedef struct _env_t {
        struct obstack obst;    /**< An obstack for temporary storage. */
  ir_graph *irg;        /**< The graph the reg alloc is running on. */
#ifdef BUILD_GRAPH
        set *nodes;                                             /**< The interference graph nodes. */
        set *edges;                                             /**< The interference graph edges. */
#endif

        bitset_t *live;                         /**< A liveness bitset. */
        bitset_t *colors;                       /**< The color mask. */
        bitset_t *in_colors;    /**< Colors used by live in values. */
        int colors_n;                                   /**< The number of colors. */
  const arch_env_t *arch_env;         /**< The arch interface environment. */
  const arch_register_class_t *cls;   /**< The current register class. */
  void *data;           /**< Some pointer, to which different
                          phases can attach data to. */
} env_t;


typedef struct _be_chordal_dump_params_t {
        int x_dist;
        int y_dist;
        double font_scale;
} be_chordal_dump_params_t;

static const be_chordal_dump_params_t dump_params = {
        10,
        10,
        4
};

#ifdef DUMP_INTERVALS

static INLINE void intv_filename(char *s, size_t n,
    const env_t *env, ir_node *block)
{
        ir_snprintf(s, n, "intv_%F_%s_bl%N.eps",
      env->irg, env->cls->name, block);
}

static void draw_interval_graph(const env_t *env,
    ir_node *block, const be_chordal_dump_params_t *params)
{
        int i;
        int x_dist = params->x_dist;
        int y_dist = params->y_dist;
        ir_graph *irg = env->irg;
  struct list_head *border_head = get_block_border_head(block);

        FILE *f;
        char buf[1024];

  intv_filename(buf, sizeof(buf), env, block);

        if((f = fopen(buf, "wt")) != NULL) {
                border_t *b;
                int *seen = xcalloc(get_graph_node_count(irg), sizeof(seen[0]));
                int last_pos = list_empty(border_head) ? 0 : list_entry(border_head->prev, border_t, list)->step;
                int max_col = 0;

                list_for_each_entry_reverse(border_t, b, border_head, list) {
                        const ir_node *irn = b->irn;
                        int col = get_irn_color(irn);
                        max_col = max_col > col ? max_col : col;
                }

                fprintf(f, "%%!PS-Adobe-2.0\n");
                fprintf(f, "%%%%BoundingBox: -10 -10 %d %d\n",
                                x_dist * last_pos + x_dist, y_dist * max_col + y_dist);
                fprintf(f, "/mainfont /Courier findfont %f scalefont def\n", params->font_scale);
                fprintf(f, "mainfont setfont\n");
                fprintf(f, "0.2 setlinewidth\n");

                for(i = 0; i <= last_pos; ++i) {
                        fprintf(f, "0 0 0 setrgbcolor\n");
                        fprintf(f, "%d %d moveto\n", i * x_dist, -2);
                        fprintf(f, "%d %d lineto\n", i * x_dist, max_col * y_dist + 2);
                        fprintf(f, "stroke\n");
                }
                fprintf(f, "0.5 setlinewidth\n");

                list_for_each_entry_reverse(border_t, b, border_head, list) {
                        const ir_node *irn = b->irn;
                        int nr = get_irn_graph_nr(irn);

                        if(b->is_def)
                                seen[nr] = b->step;
                        else {
                                int col = get_irn_color(irn);

                                int pos = last_pos - seen[nr];
                                int end_pos = last_pos - b->step;
                                int live_in = is_live_in(block, irn);
                                int live_end = is_live_end(block, irn);
                                int y_val = y_dist * col;

                                int red = 0;
                                int green = live_end;
                                int blue = live_in;

                                fprintf(f, "0 0 0 setrgbcolor\n");
                                fprintf(f, "%d %d moveto\n", x_dist * pos + 2, y_val + 2);
                                ir_fprintf(f, "(%n/%d%s) show\n", irn, nr, is_phi_operand(irn) ? "*" : "");
                                fprintf(f, "%d %d %d setrgbcolor\n", red, green, blue);
                                fprintf(f, "%d %d moveto\n", x_dist * pos, y_val);
                                fprintf(f, "%d %d lineto\n", (x_dist * end_pos) - 5, y_val);
                                fprintf(f, "stroke\n");
                        }
                }

                free(seen);
                fclose(f);
        }
}

static void dump_block(ir_node *bl, void *data)
{
  const env_t *env = data;
  FILE *f = env->data;
  char buf[128];

  draw_interval_graph(env, bl, &dump_params);

  intv_filename(buf, sizeof(buf), env, bl);
  ir_fprintf(f, "\tb%N [shape=\"epsf\" shapefile=\"%s\"];\n", bl, buf);
}

static void dump_edges(ir_node *bl, void *data)
{
  const env_t *env = data;
  FILE *f = env->data;
  int i, n;
  ir_node *dom;

#if 0
  for(i = 0, n = get_irn_arity(bl); i < n; ++i) {
    ir_node *pred = get_irn_n(bl, i);
    ir_fprintf(f, "\tb%N -> b%N;\n", get_nodes_block(pred), bl);
  }
#endif

  for(dom = get_Block_dominated_first(bl); dom;
      dom = get_Block_dominated_next(dom)) {

    ir_fprintf(f, "\tb%N -> b%N;\n", dom, bl);
  }
}

static void dump_intv_cfg(env_t *env)
{
  FILE *f;
  char buf[128];

  ir_snprintf(buf, sizeof(buf), "intv_cfg_%s_%F.dot",
      env->cls->name, env->irg);

  if((f = fopen(buf, "wt")) != NULL) {
    void *old_data = env->data;

    env->data = f;
    ir_fprintf(f, "digraph G {\n");
    ir_fprintf(f, "\tgraph [rankdir=\"LR\", ordering=\"out\"];\n");
    dom_tree_walk_irg(env->irg, dump_block, dump_edges, env);
    // irg_block_walk_graph(env->irg, dump_block, dump_edges, env);
    ir_fprintf(f, "}\n");
    fclose(f);

    env->data = old_data;
  }
}

#endif

#ifdef BUILD_GRAPH

#define IF_EDGE_HASH(e) ((e)->src)
#define IF_NODE_HASH(n) ((n)->nnr)

static int if_edge_cmp(const void *p1, const void *p2, size_t size)
{
        const if_edge_t *e1 = p1;
        const if_edge_t *e2 = p2;

        return !(e1->src == e2->src && e1->tgt == e2->tgt);
}

static int if_node_cmp(const void *p1, const void *p2, size_t size)
{
        const if_node_t *n1 = p1;
        const if_node_t *n2 = p2;

        return n1->nnr != n2->nnr;
}

static INLINE if_edge_t *edge_init(if_edge_t *edge, int src, int tgt)
{
        /* Bring the smaller entry to src. */
        if(src > tgt) {
                edge->src = tgt;
                edge->tgt = src;
        } else {
                edge->src = src;
                edge->tgt = tgt;
        }

        return edge;
}

static INLINE void add_if(const env_t *env, int src, int tgt)
{
        if_edge_t edge;
        if_node_t node, *src_node, *tgt_node;
        /* insert edge */
        edge_init(&edge, src, tgt);
        set_insert(env->edges, &edge, sizeof(edge), IF_EDGE_HASH(&edge));

        /* insert nodes */
        node.nnr = src;
        node.neighb = pset_new_ptr(8);
        src_node = set_insert(env->nodes, &node, sizeof(node), IF_NODE_HASH(&node));
        node.nnr = tgt;
        node.neighb = pset_new_ptr(8);
        tgt_node = set_insert(env->nodes, &node, sizeof(node), IF_NODE_HASH(&node));

        /* insert neighbors into nodes */
        pset_insert_ptr(src_node->neighb, tgt_node);
        pset_insert_ptr(tgt_node->neighb, src_node);
}

static INLINE int are_connected(const env_t *env, int src, int tgt)
{
        if_edge_t edge;
        edge_init(&edge, src, tgt);
        return set_find(env->edges, &edge, sizeof(edge), IF_EDGE_HASH(&edge)) != NULL;
}

int ifg_has_edge(const ir_graph *irg, if_node_t *n1, if_node_t* n2) {
        return are_connected(get_irg_ra_link(irg), n1->nnr, n2->nnr);
}

static void dump_ifg(ir_graph *irg, set *edges, const char *filename)
{
        static const char *colors[] = {
                "coral",
                "azure",
                "bisque",
                "aliceblue",
                "blanchedalmond",
                "deeppink",
                "cornsilk",
                "blueviolet",
                "floralwhite",
                "hotpink",
                "gainsboro",
                "indianred",
                "cornflowerblue",
                "ghostwhite",
                "lightpink",
                "palegoldenrod",
                "darkslateblue",
                "honeydew",
                "ivory",
                "lavender",
                "mediumvioletred",
                "indigo",
                "lavenderblush",
                "lemonchiffon",
                "linen",
                "pink",
                "mintcream",
                "red",
                "mediumblue",
                "mistyrose",
                "mediumslateblue",
                "moccasin",
                "tomato",
                "forestgreen",
                "midnightblue",
                "navajowhite",
                "navy",
                "oldlace",
                "greenyellow",
                "navyblue",
                "papayawhip",
                "lawngreen",
                "powderblue",
                "peachpuff",
                "seashell",
                "snow",
                "thistle",
                "wheat",
                "darkkhaki",
                "mintcream",
                "khaki",
                "Magentas",
                "whitesmoke",
                "peru",
                "palegreen",
                "blueviolet",
                "rosybrown",
                "saddlebrown",
                "springgreen",
                "darkviolet",
                "darkslategray",
                "dimgray",
                "sienna",
                "gray",
                "tan",
                "gray",
                "mediumvioletred",
                "lightgray",
                "Oranges",
                "cyan",
                "lightslategray",
                "darkorange",
                "slategray",
                "orangered",
                "mediumturquoise",
                "violet",
                "paleturquoise"
        };

        static const int n_colors = sizeof(colors) / sizeof(colors[0]);

        FILE *f;

        if((f = fopen(filename, "wt")) != NULL) {
                bitset_pos_t pos;
                int n_edges = 0;
                if_edge_t *edge;
                bitset_t *bs = bitset_malloc(get_graph_node_count(irg));

                ir_fprintf(f, "graph \"%F\" {\n", irg);
                fprintf(f, "\tnode [shape=box,style=filled]\n");

                for(edge = set_first(edges); edge; edge = set_next(edges)) {
                        bitset_set(bs, edge->src);
                        bitset_set(bs, edge->tgt);
                        n_edges++;
                }

                fprintf(f, "\tx [label=\"nodes: %u, edges: %d\"]\n", bitset_popcnt(bs), n_edges);

                bitset_foreach(bs, pos) {
                        int nr = (int) pos;
                        ir_node *irn = get_irn_for_graph_nr(irg, nr);
                        int color = get_irn_color(irn);

                        ir_fprintf(f, "\tn%d [label=\"%n\",color=\"%s\"]\n", nr, irn,
                                        color >= 0 && color < n_colors ? colors[color] : "black");
                }

                for(edge = set_first(edges); edge; edge = set_next(edges)) {
                        fprintf(f, "\tn%d -- n%d [len=5]\n", edge->src, edge->tgt);
                }

                fprintf(f, "}\n");
                fclose(f);

                bitset_free(bs);
        }

}

#endif /* BUILD_GRAPH */


/**
 * Add an interval border to the list of a block's list
 * of interval border.
 * @note You always have to create the use before the def.
 * @param env The environment.
 * @param head The list head to enqueue the borders.
 * @param irn The node (value) the border belongs to.
 * @param pressure The pressure at this point in time.
 * @param step A time step for the border.
 * @param is_def Is the border a use or a def.
 * @return The created border.
 */
static INLINE border_t *border_add(env_t *env, struct list_head *head,
                        ir_node *irn, unsigned step, unsigned pressure,
                        unsigned is_def, unsigned is_real)
{
        border_t *b;

        if(!is_def) {
                border_t *def;

                b = obstack_alloc(&env->obst, sizeof(*b));

                /* also allocate the def and tie it to the use. */
                def = obstack_alloc(&env->obst, sizeof(*def));
                b->other_end = def;
                def->other_end = b;

                /*
                 * Set the link field of the irn to the def.
                 * This strongly relies on the fact, that the use is always
                 * made before the def.
                 */
                set_irn_link(irn, def);

#ifdef DEBUG_libfirm
                b->magic = BORDER_FOURCC;
                def->magic = BORDER_FOURCC;
#endif
        }

        /*
         * If the def is encountered, the use was made and so was the
         * the def node (see the code above). It was placed into the
         * link field of the irn, so we can get it there.
         */
        else {
                b = get_irn_link(irn);

#ifdef DEBUG_libfirm
                assert(b && b->magic == BORDER_FOURCC && "Illegal border encountered");
#endif
        }

        b->pressure = pressure;
        b->is_def = is_def;
        b->is_real = is_real;
        b->irn = irn;
        b->step = step;
        list_add_tail(&b->list, head);
        DBG((dbg, LEVEL_5, "\t\t%s adding %n, step: %d\n",
                                is_def ? "def" : "use", irn, step));

        return b;
}

/**
 * Annotate the register pressure to the nodes and compute
 * the liveness intervals.
 * @param block The block to do it for.
 * @param env_ptr The environment.
 */
static void pressure(ir_node *block, void *env_ptr)
{
/* Convenience macro for a def */
#define border_def(irn, step, real) \
        border_add(env, head, irn, step, pressure--, 1, real)

/* Convenience macro for a use */
#define border_use(irn, step, real) \
        border_add(env, head, irn, step, ++pressure, 0, real)

        env_t *env = env_ptr;
        bitset_t *live = env->live;
        ir_node *irn;

        int i, n;
        unsigned step = 0;
        unsigned pressure = 0;
        struct list_head *head;
        pset *live_in = get_live_in(block);
        pset *live_end = get_live_end(block);
  const arch_register_class_t *cls = env->cls;

        DBG((dbg, LEVEL_1, "Computing pressure in block %n\n", block));
        bitset_clear_all(live);

        /* Set up the border list in the block info */
        head = &get_ra_block_info(block)->border_head;
        INIT_LIST_HEAD(head);

        /*
         * Make final uses of all values live out of the block.
         * They are neccessary to build up real intervals.
         */
        for(irn = pset_first(live_end); irn; irn = pset_next(live_end)) {
                DBG((dbg, LEVEL_3, "\tMaking live: %n/%d\n", irn, get_irn_graph_nr(irn)));
                bitset_set(live, get_irn_graph_nr(irn));
    if(arch_irn_has_reg_class(env->arch_env, irn, 0, cls))
      border_use(irn, step, 0);
        }

        ++step;

        /*
         * Determine the last uses of a value inside the block, since they are
         * relevant for the interval borders.
         */
        sched_foreach_reverse(block, irn) {
                DBG((dbg, LEVEL_1, "\tinsn: %n, pressure: %d\n", irn, pressure));
                DBG((dbg, LEVEL_2, "\tlive: %b\n", live));

                /* Erase the color of each node encountered. */
                set_irn_color(irn, NO_COLOR);

    /*
     * If the node defines some value, which can put into a
     * register of the current class, make a border for it.
     */
                if(arch_irn_has_reg_class(env->arch_env, irn, 0, cls)) {
      bitset_pos_t elm;
                        int nr = get_irn_graph_nr(irn);

                        bitset_clear(live, nr);
                        border_def(irn, step, 1);

#ifdef BUILD_GRAPH
      bitset_foreach(live, elm)
        add_if(env, nr, (int) elm);
#endif
                }

                /*
                 * If the node is no phi node we can examine the uses.
                 */
                if(!is_Phi(irn)) {
                        for(i = 0, n = get_irn_arity(irn); i < n; ++i) {
                                ir_node *op = get_irn_n(irn, i);

                                if(arch_irn_has_reg_class(env->arch_env, op, 0, cls)) {
                                        int nr = get_irn_graph_nr(op);

                                        DBG((dbg, LEVEL_4, "\t\tpos: %d, use: %n\n", i, op));

                                        if(!bitset_is_set(live, nr)) {
                                                border_use(op, step, 1);
                                                bitset_set(live, nr);
                                        }
                                }
                        }
                }

                ++step;
        }

        /*
         * Add initial defs for all values live in.
         */
        for(irn = pset_first(live_in); irn; irn = pset_next(live_in)) {
                if(arch_irn_has_reg_class(env->arch_env, irn, 0, cls)) {

                        /* Mark the value live in. */
                        bitset_set(live, get_irn_graph_nr(irn));

                        /* Add the def */
                        border_def(irn, step, 0);
                }
        }
}

static void assign(ir_node *block, void *env_ptr)
{
        env_t *env = env_ptr;
        struct obstack *obst = &env->obst;
        bitset_t *live = env->live;
        bitset_t *colors = env->colors;
        bitset_t *in_colors = env->in_colors;
  const arch_register_class_t *cls = env->cls;

        /* Mark the obstack level and allocate the temporary tmp_colors */
        void *obstack_level = obstack_base(obst);
        /*bitset_t *tmp_colors = bitset_obstack_alloc(obst, env->colors_n);*/

        const ir_node *irn;
        border_t *b;
        struct list_head *head = &get_ra_block_info(block)->border_head;
        pset *live_in = get_live_in(block);

        bitset_clear_all(live);
        bitset_clear_all(colors);
        bitset_clear_all(in_colors);

        DBG((dbg, LEVEL_4, "Assigning colors for block %n\n", block));
        DBG((dbg, LEVEL_4, "\tusedef chain for block\n"));
        list_for_each_entry(border_t, b, head, list) {
                DBG((dbg, LEVEL_4, "\t%s %n/%d\n", b->is_def ? "def" : "use",
                                        b->irn, get_irn_graph_nr(b->irn)));
        }

        /*
         * Add initial defs for all values live in.
         * Since their colors have already been assigned (The dominators were
         * allocated before), we have to mark their colors as used also.
         */
        for(irn = pset_first(live_in); irn; irn = pset_next(live_in)) {
                if(arch_irn_has_reg_class(env->arch_env, irn, 0, cls)) {
      const arch_register_t *reg = arch_get_irn_register(env->arch_env, irn, 0);
      int col;

      assert(reg && "Nodfe must have been assigned a register");
                        col = arch_register_get_index(reg);

                        /* Mark the color of the live in value as used. */
                        bitset_set(colors, col);
                        bitset_set(in_colors, col);

                        /* Mark the value live in. */
                        bitset_set(live, get_irn_graph_nr(irn));
                }
        }

        /*
         * Mind that the sequence of defs from back to front defines a perfect
         * elimination order. So, coloring the definitions from first to last
         * will work.
         */
        list_for_each_entry_reverse(border_t, b, head, list) {
                ir_node *irn = b->irn;
                int nr = get_irn_graph_nr(irn);

                /*
                 * Assign a color, if it is a local def. Global defs already have a
                 * color.
                 */
                if(b->is_def && !is_live_in(block, irn)) {
      const arch_register_t *reg;
                        int col = NO_COLOR;

                        DBG((dbg, LEVEL_4, "\tcolors in use: %b\n", colors));

      col = bitset_next_clear(colors, 0);
      reg = arch_register_for_index(env->cls, col);

      assert(arch_get_irn_register(env->arch_env, irn, 0) == NULL
          && "This node must not have been assigned a register yet");
                        assert(!bitset_is_set(live, nr) && "Value's definition must not have been encountered");

                        bitset_set(colors, col);
                        bitset_set(live, nr);

                        arch_set_irn_register(env->arch_env, irn, 0, reg);
                        DBG((dbg, LEVEL_1, "\tassigning register %s(%d) to %n\n",
            arch_register_get_name(reg), col, irn));
                }

                /* Clear the color upon a use. */
                else if(!b->is_def) {
      const arch_register_t *reg = arch_get_irn_register(env->arch_env, irn, 0);
                        int col;

      assert(reg && "Register must have been assigned");

      col = arch_register_get_index(reg);
                        assert(bitset_is_set(live, nr) && "Cannot have a non live use");

                        bitset_clear(colors, col);
                        bitset_clear(live, nr);
                }
        }

        /* Free the auxillary data on the obstack. */
        obstack_free(obst, obstack_level);
}

void be_ra_chordal_init(void)
{
        dbg = firm_dbg_register(DBG_BERA);
        firm_dbg_set_mask(dbg, 0);
}

void be_ra_chordal(ir_graph *irg,
    const arch_env_t *arch_env,
    const arch_register_class_t *cls)
{
        int node_count = get_graph_node_count(irg);
  int colors_n = arch_register_class_n_regs(cls);
        env_t *env = malloc(sizeof(*env));

        if(get_irg_dom_state(irg) != dom_consistent)
                compute_doms(irg);

        obstack_init(&env->obst);

#ifdef BUILD_GRAPH
        env->edges = new_set(if_edge_cmp, node_count);
        env->nodes = new_set(if_node_cmp, node_count);
#endif

        env->live = bitset_obstack_alloc(&env->obst, node_count);
        env->colors = bitset_obstack_alloc(&env->obst, colors_n);
        env->in_colors = bitset_obstack_alloc(&env->obst, colors_n);
        env->colors_n = colors_n;
  env->cls = cls;
  env->arch_env = arch_env;
  env->irg = irg;

        /* First, determine the pressure */
        dom_tree_walk_irg(irg, pressure, NULL, env);

        /* Insert probable spills */
        be_ra_chordal_spill(irg);

        /* Assign the colors */
        dom_tree_walk_irg(irg, assign, NULL, env);

#ifdef DUMP_IFG
        {
                char buf[128];

                ir_snprintf(buf, sizeof(buf), "ifg_%F.dot", irg);
                dump_ifg(irg, env->edges, buf);
        }
#endif

#ifdef DUMP_INTERVALS
  dump_intv_cfg(env);
#endif

        set_irg_ra_link(irg, env);
}

void be_ra_chordal_done(ir_graph *irg)
{
        env_t *env = get_irg_ra_link(irg);

#ifdef BUILD_GRAPH
        {
                if_node_t *ifn;
                for(ifn = set_first(env->nodes); ifn; ifn = set_next(env->nodes))
                        free(ifn->neighb);
                free(env->nodes);
                free(env->edges);
        }
#endif

        obstack_free(&env->obst, NULL);
        free(env);
}

int phi_ops_interfere(const ir_node *a, const ir_node *b)
{
#ifdef BUILD_GRAPH
        ir_graph *irg = get_irn_irg(a);
        env_t *env = get_irg_ra_link(irg);

        assert(irg == get_irn_irg(b) && "Both nodes must be in the same graph");

        return are_connected(env, get_irn_graph_nr(a), get_irn_graph_nr(b));
#else
        return values_interfere(a, b);
#endif /* BUILD_GRAPH */
}

#ifdef BUILD_GRAPH
/** TODO remove this
 * Deprecated. Use be_ra_get_ifg_edges instead.
 */
set *be_ra_get_ifg(ir_graph *irg) {
        return ((env_t *)get_irg_ra_link(irg))->edges;
}

set *be_ra_get_ifg_edges(ir_graph *irg) {
        return ((env_t *)get_irg_ra_link(irg))->edges;
}

set *be_ra_get_ifg_nodes(ir_graph *irg) {
        return ((env_t *)get_irg_ra_link(irg))->nodes;
}

#endif