typo fixed

[libfirm] / ir / be / beraextern.c

/*
 * Copyright (C) 1995-2008 University of Karlsruhe.  All right reserved.
 *
 * This file is part of libFirm.
 *
 * This file may be distributed and/or modified under the terms of the
 * GNU General Public License version 2 as published by the Free Software
 * Foundation and appearing in the file LICENSE.GPL included in the
 * packaging of this file.
 *
 * Licensees holding valid libFirm Professional Edition licenses may use
 * this file in accordance with the libFirm Commercial License.
 * Agreement provided with the Software.
 *
 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE.
 */

/**
 * @file
 * @brief       Implementation of the RA-Interface for an external, (non-SSA) register allocator.
 * @author      Daniel Grund
 * @date        17.01.2006
 * @version     $Id$
 *
 * The external register allocator is a program:
 *    PROG -i INPUTFILE -o OUTPUTFILE
 *
 *   1) Input file defines the interference graph
 *   2) Output file contains the instructions to perform
 *


The input file format
----------------------

inputfile       ::= regs nodes interf affinities .

regs            ::= 'regs' regcount .                                           // Anzahl der register (0..regcount-1), die zur Verfuegung stehen

nodes           ::= 'nodes' '{' node* '}' .                                     // All nodes in the graph

node            ::= node-info
                          | node-info '<' reg-nr '>' .                          // Reg-nr is present in case of constraints

node-info       ::= node-nr spill-costs .

interf          ::= 'interferences' '{' i-edge* '}' .           // Interference edges of the graph

i-edge          ::= '(' node-nr ',' node-nr ')' .

affinities      ::= 'affinities' '{' a-edge* '}' .                      // Affinity edges of the graph

a-edge          ::= '(' node-nr ',' node-nr ',' weight ')' .


weight, regcount, node-nr ::= int32 .
spill-costs ::= int32 .                                                                 // negative spill costs indicate unspillable

The output file format
-----------------------

outputfile      ::= spills | allocs .

spills          ::= 'spills' node-nr+ .

allocs          ::= 'allocs' alloc* .

alloc           ::= node-nr reg-nr .

*/
#ifdef NOT_PORTED
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include "lc_opts.h"
#include "lc_opts_enum.h"

#include "set.h"
#include "pset.h"
#include "pmap.h"
#include "bitset.h"
#include "raw_bitset.h"
#include "xmalloc.h"

#include "irprintf_t.h"
#include "irnode_t.h"
#include "irgraph_t.h"
#include "irgwalk.h"
#include "iredges_t.h"
#include "irdom_t.h"
#include "phiclass.h"

#include "bemodule.h"
#include "beabi.h"
#include "bearch_t.h"
#include "benode_t.h"
#include "beirgmod.h"
#include "besched_t.h"
#include "beutil.h"
#include "belive_t.h"
#include "beinsn_t.h"

#include "bessadestrsimple.h"

#define DBG_LEVEL 2

/**
 * Environment with all the needed stuff
 */
typedef struct _be_raext_env_t {
        arch_env_t *aenv;
        const arch_register_class_t *cls;
        be_irg_t *birg;
        ir_graph *irg;

        FILE *f;                                /**< file handle used for out- and input file */
        set *vars;                              /**< contains all be_var_info_t */
        int n_cls_vars;                 /**< length of the array cls_vars */
        be_var_info_t **cls_vars;       /**< only the var_infos for current cls. needed for double iterating */
        DEBUG_ONLY(firm_dbg_module_t *dbg;)
} be_raext_env_t;



/******************************************************************************
    _    _      _
   | |  | |    | |
   | |__| | ___| |_ __   ___ _ __ ___
   |  __  |/ _ \ | '_ \ / _ \ '__/ __|
   | |  | |  __/ | |_) |  __/ |  \__ \
   |_|  |_|\___|_| .__/ \___|_|  |___/
                 | |
                 |_|
 *****************************************************************************/


#define pset_foreach(pset, irn)  for(irn=pset_first(pset); irn; irn=pset_next(pset))
#define set_foreach(set, e)  for(e=set_first(set); e; e=set_next(set))

/**
 * Checks if _the_ result of the irn belongs to the
 * current register class (raenv->cls)
 * NOTE: Only the first result is checked.
 */
#define is_res_in_reg_class(irn) arch_irn_has_reg_class(raenv->aenv, irn, -1, raenv->cls)

static INLINE ir_node *get_first_non_phi(pset *s) {
        ir_node *irn;

        pset_foreach(s, irn)
                if (!is_Phi(irn)) {
                        pset_break(s);
                        return irn;
                }

        assert(0 && "There must be a non-phi-irn in this");
        return NULL;
}

static INLINE ir_node *get_first_phi(pset *s) {
        ir_node *irn;

        pset_foreach(s, irn)
                if (is_Phi(irn)) {
                        pset_break(s);
                        return irn;
                }

        assert(0 && "There must be a phi in this");
        return NULL;
}

static int get_loop_weight(ir_node *irn) {
        int cost = 0;
        ir_loop *loop = get_irn_loop(get_nodes_block(irn));

        if (loop) {
                int d = get_loop_depth(loop);
                cost = d*d;
        }
        return cost+1;
}

#define get_const_weight(irn) (1)

#define get_spill_weight(irn)    get_loop_weight(irn)
#define get_reload_weight(irn)   get_loop_weight(irn)
#define get_affinity_weight(irn) get_loop_weight(irn)

/******************************************************************************
    _____                _            _____            _
   / ____|              | |          / ____|          (_)
  | |     ___  _ __  ___| |_ _ __   | |     ___  _ __  _  ___  ___
  | |    / _ \| '_ \/ __| __| '__|  | |    / _ \| '_ \| |/ _ \/ __|
  | |___| (_) | | | \__ \ |_| |     | |___| (_) | |_) | |  __/\__ \
   \_____\___/|_| |_|___/\__|_|      \_____\___/| .__/|_|\___||___/
                                                | |
                                                |_|
 *****************************************************************************/

static void handle_constraints_insn(be_raext_env_t *env, be_insn_t *insn)
{
        ir_node *bl = get_nodes_block(insn->irn);
        int i;

        for(i = 0; i < insn->use_start; ++i) {
                be_operand_t *op = &insn->ops[i];

                if(op->has_constraints) {
                        ir_node *cpy = be_new_Copy(op->req->cls, env->irg, bl, op->carrier);
                        sched_add_before(insn->next_insn, cpy);
                        edges_reroute(op->carrier, cpy, env->irg);
                }
        }

        for(i = insn->use_start; i < insn->n_ops; ++i) {
                be_operand_t *op = &insn->ops[i];

                if(op->has_constraints) {
                        ir_node *cpy = be_new_Copy(op->req->cls, env->irg, bl, op->carrier);
                        sched_add_before(insn->irn, cpy);
                        set_irn_n(insn->irn, op->pos, cpy);
                        be_set_constr_limited(cpy, BE_OUT_POS(0), op->req);
                }
        }
}

static void handle_constraints_block(ir_node *bl, void *data)
{
        be_raext_env_t *raenv = data;
        int active            = bl != get_irg_start_block(raenv->irg);

        ir_node *irn;
        be_insn_env_t ie;
        struct obstack obst;

        ie.cls           = raenv->cls;
        ie.aenv          = raenv->aenv;
        ie.obst          = &obst;
        ie.ignore_colors = NULL;
        obstack_init(&obst);

        irn = sched_first(bl);
        while(!sched_is_end(irn)) {
                be_insn_t *insn = be_scan_insn(&ie, irn);

                if(insn->has_constraints)
                        handle_constraints_insn(raenv, insn);

                if(be_is_Barrier(irn))
                        active = !active;

                irn = insn->next_insn;
                obstack_free(&obst, insn);
        }
}

static void handle_constraints(be_raext_env_t *raenv) {
        irg_block_walk_graph(raenv->irg, NULL, handle_constraints_block, raenv);
}




/******************************************************************************
    _____
   |  __ \
   | |  | |_   _ _ __ ___  _ __   ___ _ __
   | |  | | | | | '_ ` _ \| '_ \ / _ \ '__|
   | |__| | |_| | | | | | | |_) |  __/ |
   |_____/ \__,_|_| |_| |_| .__/ \___|_|
                          | |
                          |_|
 *****************************************************************************/


static void extract_vars_of_cls(be_raext_env_t *raenv) {
        int count = 0;
        be_var_info_t *vi;

        raenv->cls_vars = xmalloc(set_count(raenv->vars) * sizeof(*raenv->cls_vars));
        assert(raenv->cls_vars);

        set_foreach(raenv->vars, vi)
                if (is_res_in_reg_class(get_first_non_phi(vi->values)))
                        raenv->cls_vars[count++] = vi;

        raenv->cls_vars = realloc(raenv->cls_vars, count * sizeof(*raenv->cls_vars));
        assert(raenv->cls_vars);

        raenv->n_cls_vars = count;
}


/**
 * Check if node irn has a limited-constraint at position pos.
 * If yes, dump it to FILE raenv->f
 */
static INLINE void dump_constraint(be_raext_env_t *raenv, ir_node *irn, int pos) {
        const arch_register_req_t *req;

        req = arch_get_register_req(raenv->aenv, irn, pos);
        if (arch_register_req_is(req, limited)) {
                unsigned reg_nr;

                reg_nr = rbitset_next(req->limited, 0, 1);
                fprintf(raenv->f, "<%d>", reg_nr);
                assert(rbitset_popcnt(req->limited, raenv->cls->n_regs) <= 1
                                && "Constraints with more than 1 possible register are not supported");
        }
}

#define UNSPILLABLE -1

static INLINE int get_spill_costs(be_raext_env_t *raenv, be_var_info_t *vi) {
        ir_node *irn;
        int c_spills=0, c_reloads=0;

        pset_foreach(vi->values, irn) {
                if (arch_irn_is(raenv->aenv, irn, ignore) || be_is_Reload(irn)) {
                        pset_break(vi->values);
                        return UNSPILLABLE;
                }

                if (is_Phi(irn)) {
                        /* number of reloads is the number of non-phi uses of all values of this var */
                        const ir_edge_t *edge;
                        foreach_out_edge(irn, edge)
                                if (!is_Phi(edge->src))
                                        c_reloads += get_reload_weight(edge->src);
                } else {
                        /* number of spills is the number of non-phi values for this var */
                        c_spills += get_spill_weight(irn);
                }
        }

        return c_spills + c_reloads;
}

static void dump_nodes(be_raext_env_t *raenv) {
        FILE *f = raenv->f;
        int i;

        fprintf(f, "\nnodes {\n");

        for (i=0; i<raenv->n_cls_vars; ++i) {
                be_var_info_t *vi = raenv->cls_vars[i];

                if (vi->var_nr == SET_REMOVED)
                        continue;

                fprintf(f, "%d %d", vi->var_nr, get_spill_costs(raenv, vi));
                dump_constraint(raenv, get_first_non_phi(vi->values), -1);
                fprintf(f, "\n");
        }

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


static void dump_interferences(be_raext_env_t *raenv) {
        int i,o;
        be_var_info_t *vi1, *vi2;
        ir_node *irn1, *irn2;
        FILE *f = raenv->f;
        be_lv_t *lv = raenv->birg->lv;

        fprintf(f, "\ninterferences {\n");

        for (i=0; i<raenv->n_cls_vars; ++i) {
                vi1 = raenv->cls_vars[i];

                if (vi1->var_nr == SET_REMOVED)
                        continue;

                for (o=i+1; o<raenv->n_cls_vars; ++o) {
                        vi2 = raenv->cls_vars[o];

                        if (vi2->var_nr == SET_REMOVED)
                                continue;

                        pset_foreach(vi1->values, irn1)
                                pset_foreach(vi2->values, irn2)
                                        if (values_interfere(lv, irn1, irn2)) {
                                                pset_break(vi1->values);
                                                pset_break(vi2->values);
                                                fprintf(f, "(%d, %d)\n", vi1->var_nr, vi2->var_nr);
                                                goto NextVar;
                                        }

NextVar: ;
                }
        }
        fprintf(f, "}\n");
}

static void dump_affinities_walker(ir_node *irn, void *env) {
        be_raext_env_t *raenv = env;
        const arch_register_req_t *req;
        int pos, max;
        be_var_info_t *vi1, *vi2;

        if (arch_get_irn_reg_class(raenv->aenv, irn, -1) != raenv->cls || arch_irn_is(raenv->aenv, irn, ignore))
                return;

        vi1 = be_get_var_info(irn);

        /* copies have affinities */
        if (arch_irn_class_is(raenv->aenv, irn, copy)) {
                ir_node *other = be_get_Copy_op(irn);

                if (! arch_irn_is(raenv->aenv, other, ignore)) {
                        vi2 = be_get_var_info(other);

                        fprintf(raenv->f, "(%d, %d, %d)\n",  vi1->var_nr, vi2->var_nr, get_affinity_weight(irn));
                }
        }


        /* should_be_equal constraints are affinites */
        for (pos = 0, max = get_irn_arity(irn); pos<max; ++pos) {
                req = arch_get_register_req(raenv->aenv, irn, pos);
                if (arch_register_req_is(req, should_be_same)) {
                        const int* i;
                        for (i = req->other_same; i != ENDOF(req->other_same); ++i) {
                                ir_node *other;

                                if (*i == -1) break;

                                other = get_irn_n(skip_Proj(irn), *i);
                                if(arch_irn_is(raenv->aenv, other, ignore)) {
                                        vi2 = be_get_var_info(other);
                                        fprintf(raenv->f, "(%d, %d, %d)\n",  vi1->var_nr, vi2->var_nr, get_affinity_weight(irn));
                                }
                        }
                }
        }
}


static void dump_affinities(be_raext_env_t *raenv) {
        fprintf(raenv->f, "\naffinities {\n");
        irg_walk_graph(raenv->irg, NULL, dump_affinities_walker, raenv);
        fprintf(raenv->f, "}\n");
}

/**
 * Dump all information needed by the external
 * register allocator to a single file.
 */
static void dump_to_file(be_raext_env_t *raenv, char *filename) {
        FILE *f;

        if (!(f = fopen(filename, "wt"))) {
                fprintf(stderr, "Could not open file %s for writing\n", filename);
                assert(0);
                exit(0xdeadbeef);
        }
        raenv->f = f;

        /* dump register info */
        fprintf(f, "regs %d\n", arch_register_class_n_regs(raenv->cls));

        /* dump the interference graph */
        dump_nodes(raenv);
        dump_interferences(raenv);
        dump_affinities(raenv);

        fclose(f);
}

/******************************************************************************
    ______                     _
   |  ____|                   | |
   | |__  __  _____  ___ _   _| |_ ___
   |  __| \ \/ / _ \/ __| | | | __/ _ \
   | |____ >  <  __/ (__| |_| | ||  __/
   |______/_/\_\___|\___|\__,_|\__\___|
 *****************************************************************************/

/**
 * Execute the external register allocator specified in the
 * firm-option firm.be.ra.ext.callee
 */
static void execute(char *prog_to_call, char *out_file, char *result_file) {
        char cmd_line[1024];
        int ret_status;

        snprintf(cmd_line, sizeof(cmd_line), "%s -i %s -o %s", prog_to_call, out_file, result_file);
        cmd_line[sizeof(cmd_line) - 1] = '\0';

        ret_status = system(cmd_line);
        assert(ret_status != -1 && "Invokation of external register allocator failed");
        assert(ret_status == 0 && "External register allocator is unhappy with sth.");
}

/******************************************************************************
                         _         _____                 _ _
       /\               | |       |  __ \               | | |
      /  \   _ __  _ __ | |_   _  | |__) |___  ___ _   _| | |_
     / /\ \ | '_ \| '_ \| | | | | |  _  // _ \/ __| | | | | __|
    / ____ \| |_) | |_) | | |_| | | | \ \  __/\__ \ |_| | | |_
   /_/    \_\ .__/| .__/|_|\__, | |_|  \_\___||___/\__,_|_|\__|
            | |   | |       __/ |
            |_|   |_|      |___/
 *****************************************************************************/

/**
 * Spill a variable and add reloads before all uses.
 */
static INLINE void var_add_spills_and_reloads(be_raext_env_t *raenv, int var_nr) {
        be_var_info_t *vi = be_var_find(raenv->vars, var_nr);
        ir_node *spill=NULL, *ctx, *irn;
        ir_mode *mode;
        const ir_edge_t *edge, *ne;
        pset *spills  = pset_new_ptr(4);        /* the spills of this variable */
        pset *reloads = pset_new_ptr(4);        /* the reloads of this variable */
        be_lv_t *lv = raenv->birg->lv;
        be_dom_front_info_t *dom_front = raenv->birg->dom_front;
        int new_size, n_spills, n_reloads;

        assert(vi && "Variable nr does not exist!");
        assert(pset_count(vi->values) && "There are no values associated to this variable");

        /* the spill context is set to an arbitrary node of the phi-class,
         * or the node itself if it is not member of a phi class
         */
        if (pset_count(vi->values) == 1)
                ctx = get_first_non_phi(vi->values);
        else
                ctx = get_first_phi(vi->values);

        DBG((raenv->dbg, LEVEL_2, "Spill context: %+F\n", ctx));

        /* for each value of this variable insert the spills */
        pset_foreach(vi->values, irn) {
                if (is_Phi(irn)) {
                        sched_remove(irn);
                        continue;
                }

                /* all ordinary nodes must be spilled */
                DBG((raenv->dbg, LEVEL_2, "  spilling %+F\n", irn));
                spill = be_spill(raenv->aenv, irn);

                /* remember the spill */
                pset_insert_ptr(spills, spill);
        }

        assert(spill && "There must be at least one non-phi-node");

        mode = get_irn_mode(get_irn_n(spill, be_pos_Spill_val));

        /* insert reloads and wire them arbitrary*/
        pset_foreach(vi->values, irn) {
                foreach_out_edge_safe(irn, edge, ne) {
                        ir_node *reload, *src = edge->src;
                        if (is_Phi(src) || be_is_Spill(src))
                                continue;

                        /* all real uses must be reloaded */
                        DBG((raenv->dbg, LEVEL_2, "  reloading before %+F\n", src));
                        reload = be_reload(raenv->aenv, raenv->cls, edge->src, mode, spill);
                        set_irn_n(edge->src, edge->pos, reload);

                        /* remember the reload */
                        pset_insert_ptr(reloads, reload);
                }
        }

        /* correct the reload->spill pointers... */
        be_ssa_constr_set_ignore(dom_front, lv, spills, NULL);


        /****** correct the variable <--> values mapping: ******
         *
         *  - if we had a phi class it gets split into several new variables
         *  - all reloads are new variables
         */
        n_spills = pset_count(spills);
        n_reloads = pset_count(reloads);

        /* first make room for new pointers in the cls_var array */
        new_size = raenv->n_cls_vars + n_reloads + ((n_spills>1) ? n_spills : 0);
        raenv->cls_vars = realloc(raenv->cls_vars, (new_size) * sizeof(*raenv->cls_vars));
        assert(raenv->cls_vars && "Out of mem!?");

        /* if we had a real phi-class, we must... */
        if (pset_count(spills) > 1) {
                /* ...remove the old variable corresponding to the phi class */
                vi->var_nr = SET_REMOVED;

                /* ...add new vars for each non-phi-member */
                pset_foreach(spills, irn) {
                        ir_node *spilled = get_irn_n(irn, be_pos_Spill_val);
                        raenv->cls_vars[raenv->n_cls_vars++] = be_var_add_value(raenv->vars, get_irn_node_nr(spilled), spilled);
                }
        }

        /* add new variables for all reloads */
        pset_foreach(reloads, irn) {
                assert(get_irn_node_nr(irn) != 1089);
                raenv->cls_vars[raenv->n_cls_vars++] = be_var_add_value(raenv->vars, get_irn_node_nr(irn), irn);
        }

        del_pset(spills);
        del_pset(reloads);
}

#define INVALID_FILE_FORMAT assert(0 && "Invalid file format.")
#define BUFLEN 32
#define BUFCONV " %32s "

/**
 * Read in the actions performed by the external allocator.
 * Apply these transformations to the irg.
 * @return 1 if an allocation was read in. 0 otherwise.
 */
static int read_and_apply_results(be_raext_env_t *raenv, char *filename) {
        FILE *f;
        char buf[BUFLEN];
        int is_allocation = 0;

        if (!(f = fopen(filename, "rt"))) {
                fprintf(stderr, "Could not open file %s for reading\n", filename);
                assert(0);
                exit(0xdeadbeef);
        }
        raenv->f = f;

        /* read the action */
        if (fscanf(f, BUFCONV, buf) != 1)
                INVALID_FILE_FORMAT;

        /* do we spill */
        if (!strcmp(buf, "spills")) {
                int var_nr;
                while (fscanf(f, " %d ", &var_nr) == 1)
                        var_add_spills_and_reloads(raenv, var_nr);
        } else

        /* or do we allocate */
        if (!strcmp(buf, "allocs")) {
                int var_nr, reg_nr;

                is_allocation = 1;
                while (fscanf(f, " %d %d ", &var_nr, &reg_nr) == 2) {
                        ir_node *irn;
                        pset *vals = be_get_var_values(raenv->vars, var_nr);

                        assert(vals && "Variable nr does not exist!");
                        pset_foreach(vals, irn)
                                arch_set_irn_register(raenv->aenv, irn, arch_register_for_index(raenv->cls, reg_nr));
                }
        } else
                INVALID_FILE_FORMAT;

        if (!feof(f))
                INVALID_FILE_FORMAT;

        fclose(f);

        return is_allocation;
}

static void check_allocation(be_raext_env_t *raenv) {
        int i, o;
        be_lv_t *lv = raenv->birg->lv;

        for (i=0; i<raenv->n_cls_vars; ++i) {
                be_var_info_t *vi1 = raenv->cls_vars[i];

                if (vi1->var_nr == SET_REMOVED)
                        continue;

                for (o=0; o<i; ++o) {
                        be_var_info_t *vi2 = raenv->cls_vars[o];
                        ir_node *irn1, *irn2;

                        if (vi2->var_nr == SET_REMOVED)
                                continue;

                        pset_foreach(vi1->values, irn1)
                                pset_foreach(vi2->values, irn2)
                                        if (values_interfere(lv, irn1, irn2) && arch_get_irn_register(raenv->aenv, irn1) == arch_get_irn_register(raenv->aenv, irn2)) {
                                                dump_ir_block_graph_sched(raenv->irg, "ERROR");
                                                ir_fprintf(stdout, "SSA values %+F and %+F interfere. They belong to variable %d and %d respectively.\n", irn1, irn2, vi1->var_nr, vi2->var_nr);
                                                assert(0 && "ERROR graph dumped");
                                        }
                }
        }
}

/******************************************************************************
    __  __       _
   |  \/  |     (_)
   | \  / | __ _ _ _ __
   | |\/| |/ _` | | '_ \
   | |  | | (_| | | | | |
   |_|  |_|\__,_|_|_| |_|
 *****************************************************************************/

/**
 * Default values for options
 */
static char callee[128] = "\"E:/user/kimohoff/public/register allocator\"";
//static char callee[128] = "/ben/kimohoff/ipd-registerallocator/register_allocator";


/**
 * Allocate registers with an external program using a text-file interface.
 *
 * Do some computations (SSA-destruction and mapping of values--vars)
 * Write file
 * Execute external program
 * Read in results and apply them
 *
 */
static void be_ra_extern_main(be_irg_t *birg) {
        be_main_env_t *env = birg->main_env;
        ir_graph *irg = birg->irg;

        be_raext_env_t raenv;
        int clsnr, clss;

        be_assure_dom_front(birg);
        be_assure_liveness(birg);
        edges_assure(irg);

        raenv.irg      = irg;
        raenv.birg     = birg;
        raenv.aenv     = env->arch_env;
        FIRM_DBG_REGISTER(raenv.dbg, "firm.be.raextern");

        /* Insert copies for constraints */
        for(clsnr = 0, clss = arch_isa_get_n_reg_class(raenv.aenv->isa); clsnr < clss; ++clsnr) {
                raenv.cls = arch_isa_get_reg_class(raenv.aenv->isa, clsnr);
                handle_constraints(&raenv);
        }

        be_dump(irg, "-extern-constr", dump_ir_block_graph_sched);

        /* SSA destruction respectively transformation into "Conventional SSA" */
        raenv.vars = be_ssa_destr_simple(irg, env->arch_env);
        be_dump(irg, "-extern-ssadestr", dump_ir_block_graph_sched);


        /* For all register classes */
        for(clsnr = 0, clss = arch_isa_get_n_reg_class(raenv.aenv->isa); clsnr < clss; ++clsnr) {
                int done, round = 1;
                char out[256], in[256];

                raenv.cls = arch_isa_get_reg_class(raenv.aenv->isa, clsnr);

                extract_vars_of_cls(&raenv);

                do {
                        ir_snprintf(out, sizeof(out), "%F-%s-%d.ra", irg, raenv.cls->name, round);
                        ir_snprintf(in, sizeof(in), "%F-%s-%d.ra.res", irg, raenv.cls->name, round);

                        be_liveness(irg);

                        dump_to_file(&raenv, out);
                        execute(callee, out, in);
                        done = read_and_apply_results(&raenv, in);
                        be_abi_fix_stack_nodes(birg->abi);

                        ir_snprintf(in, sizeof(in), "-extern-%s-round-%d", raenv.cls->name, round);
                        be_dump(irg, in, dump_ir_block_graph_sched);

                        round++;
                } while (!done);

                check_allocation(&raenv);

                free(raenv.cls_vars);
        }

        be_dump(irg, "-extern-alloc", dump_ir_block_graph_sched);

        /* Clean up */
        free_ssa_destr_simple(raenv.vars);

        be_liveness_invalidate(be_get_birg_liveness(birg));
}

/******************************************************************************
     ____        _   _
    / __ \      | | (_)
   | |  | |_ __ | |_ _  ___  _ __  ___
   | |  | | '_ \| __| |/ _ \| '_ \/ __|
   | |__| | |_) | |_| | (_) | | | \__ \
    \____/| .__/ \__|_|\___/|_| |_|___/
          | |
          |_|
 *****************************************************************************/

static const lc_opt_enum_func_ptr_items_t ssa_destr_items[] = {
        { "simple",     (int (*)(void)) be_ssa_destr_simple }, /* TODO make (void*) casts nicer */
        { NULL,      NULL }
};

static set* (*ssa_destr)(ir_graph*,const arch_env_t*) = be_ssa_destr_simple;

static lc_opt_enum_func_ptr_var_t ssa_destr_var = {
         (int (**)(void)) &ssa_destr, ssa_destr_items
};

static const lc_opt_table_entry_t be_ra_extern_options[] = {
        LC_OPT_ENT_ENUM_FUNC_PTR("ssa_destr", "SSA destruction flavor", &ssa_destr_var),
        LC_OPT_ENT_STR("callee", "The external program to call", callee, sizeof(callee)),
        { NULL }
};

static be_ra_t be_ra_external_allocator = {
        be_ra_extern_main
};

void be_init_raextern(void) {
        lc_opt_entry_t *be_grp = lc_opt_get_grp(firm_opt_get_root(), "be");
        lc_opt_entry_t *blocksched_grp = lc_opt_get_grp(be_grp, "ra");
        lc_opt_entry_t *ext_grp = lc_opt_get_grp(blocksched_grp, "ext");

        lc_opt_add_table(ext_grp, be_ra_extern_options);

        be_register_allocator("ext", &be_ra_external_allocator);
}
BE_REGISTER_MODULE_CONSTRUCTOR(be_init_raextern);

#endif /* NOT_PORTED */