big refactoring of arch_XXX functions
[libfirm] / ir / be / bespill.c
index de8d6b6..c83653a 100644 (file)
+/*
+ * 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.
+ */
+
 /**
- * Author:      Daniel Grund, Sebastian Hack
- * Date:               29.09.2005
- * Copyright:   (c) Universitaet Karlsruhe
- * Licence:     This file protected by GPL -  GNU GENERAL PUBLIC LICENSE.
+ * @file
+ * @brief       Spill module selection; Preparation steps
+ * @author      Matthias Braun
+ * @date        29.09.2005
+ * @version     $Id$
  */
-#ifdef HAVE_CONFIG_H
 #include "config.h"
-#endif
-
-#include <stdlib.h>
 
-#include "pset.h"
-#include "irnode_t.h"
-#include "ircons_t.h"
-#include "iredges_t.h"
-#include "ident_t.h"
-#include "type_t.h"
-#include "entity_t.h"
+#include "irtools.h"
 #include "debug.h"
+#include "iredges_t.h"
+#include "raw_bitset.h"
+#include "statev.h"
 #include "irgwalk.h"
-#include "array.h"
-#include "pdeq.h"
 
-#include "belive_t.h"
-#include "besched_t.h"
 #include "bespill.h"
-#include "benode_t.h"
-#include "bechordal_t.h"
-
-#define REMAT
-/* This enables re-computation of values. Current state: Unfinished and buggy. */
-#define BUGGY_REMAT
-
-typedef struct _reloader_t reloader_t;
-typedef struct _spill_info_t spill_info_t;
-
-struct _reloader_t {
-       reloader_t *next;
-       ir_node *reloader;
-};
+#include "bemodule.h"
+#include "be.h"
+#include "belive_t.h"
+#include "beirg.h"
+#include "bearch.h"
+#include "benode.h"
+#include "besched.h"
+#include "bera.h"
+#include "beintlive_t.h"
 
-struct _spill_info_t {
-       ir_node *spilled_node;
-       reloader_t *reloaders;
-};
+#include "lc_opts.h"
+#include "lc_opts_enum.h"
 
-typedef struct _spill_ctx_t {
-       ir_node *spilled;  /**< The spilled node. */
-       ir_node *user;     /**< The node this spill is for. */
-       ir_node *spill;    /**< The spill itself. */
-} spill_ctx_t;
+DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
 
-struct _spill_env_t {
+typedef struct be_pre_spill_env_t {
+       ir_graph                    *irg;
        const arch_register_class_t *cls;
-       const be_chordal_env_t *chordal_env;
-       struct obstack obst;
-       set *spill_ctxs;
-       set *spills;                            /**< all spill_info_t's, which must be placed */
-       pset *mem_phis;                         /**< set of all special spilled phis. allocated and freed separately */
-       decide_irn_t is_mem_phi;        /**< callback func to decide if a phi needs special spilling */
-       void *data;                                     /**< data passed to all callbacks */
-       DEBUG_ONLY(firm_dbg_module_t *dbg;)
-};
-
-static int cmp_spillctx(const void *a, const void *b, size_t n) {
-       const spill_ctx_t *p = a;
-       const spill_ctx_t *q = b;
-       return !(p->user == q->user && p->spilled == q->spilled);
-}
-
-static int cmp_spillinfo(const void *x, const void *y, size_t size) {
-       const spill_info_t *xx = x;
-       const spill_info_t *yy = y;
-       return ! (xx->spilled_node == yy->spilled_node);
-}
-
-DEBUG_ONLY(
-void be_set_spill_env_dbg_module(spill_env_t *env, firm_dbg_module_t *dbg) {
-       env->dbg = dbg;
-}
-)
-
-spill_env_t *be_new_spill_env(const be_chordal_env_t *chordal_env, decide_irn_t is_mem_phi, void *data) {
-       spill_env_t *env = xmalloc(sizeof(env[0]));
-       env->spill_ctxs  = new_set(cmp_spillctx, 1024);
-       env->spills      = new_set(cmp_spillinfo, 1024);
-       env->cls         = chordal_env->cls;
-       env->is_mem_phi  = is_mem_phi;
-       env->data        = data;
-       env->chordal_env = chordal_env;
-       obstack_init(&env->obst);
-       return env;
-}
-
-void be_delete_spill_env(spill_env_t *senv) {
-       del_set(senv->spill_ctxs);
-       del_set(senv->spills);
-       obstack_free(&senv->obst, NULL);
-       free(senv);
-}
-
-static spill_ctx_t *be_get_spill_ctx(set *sc, ir_node *to_spill, ir_node *ctx_irn) {
-       spill_ctx_t templ;
-
-       templ.spilled = to_spill;
-       templ.user    = ctx_irn;
-       templ.spill   = NULL;
-
-       return set_insert(sc, &templ, sizeof(templ), HASH_COMBINE(HASH_PTR(to_spill), HASH_PTR(ctx_irn)));
-}
-
-static ir_node *be_spill_irn(spill_env_t *senv, ir_node *irn, ir_node *ctx_irn) {
-       spill_ctx_t *ctx;
-       DBG((senv->dbg, LEVEL_1, "%+F in ctx %+F\n", irn, ctx_irn));
-
-       ctx = be_get_spill_ctx(senv->spill_ctxs, irn, ctx_irn);
-       if(!ctx->spill) {
-               const be_main_env_t *env = senv->chordal_env->birg->main_env;
-               ctx->spill = be_spill(env->arch_env, irn, ctx_irn);
+} be_pre_spill_env_t;
+
+static void prepare_constr_insn(be_pre_spill_env_t *env, ir_node *node)
+{
+       const arch_register_class_t *cls = env->cls;
+       ir_node  *block      = get_nodes_block(node);
+       const ir_graph *irg  = env->irg;
+       be_irg_t       *birg = be_birg_from_irg(irg);
+       be_lv_t *lv          = be_get_irg_liveness(irg);
+       unsigned *tmp        = NULL;
+       unsigned *def_constr = NULL;
+       int       arity      = get_irn_arity(node);
+       ir_node  *def;
+
+       int i, i2;
+
+       /* Insert a copy for constraint inputs attached to a value which can't
+        * fulfill the constraint
+        * (typical example: stack pointer as input to copyb)
+        * TODO: This really just checks precolored registers at the moment and
+        *       ignores the general case of not matching in/out constraints
+        */
+       for (i = 0; i < arity; ++i) {
+               ir_node                   *op  = get_irn_n(node, i);
+               const arch_register_req_t *req = arch_get_irn_register_req_in(node, i);
+               const arch_register_t     *reg;
+               ir_node                   *copy;
+
+               if (req->cls != cls)
+                       continue;
+               reg = arch_get_irn_register(op);
+               if (reg == NULL)
+                       continue;
+
+               /* precolored with an ignore register (which is not a joker like
+                  unknown/noreg) */
+               if ((reg->type & arch_register_type_joker) ||
+                   rbitset_is_set(birg->allocatable_regs, reg->global_index))
+                       continue;
+
+               if (! (req->type & arch_register_req_type_limited))
+                       continue;
+               if (rbitset_is_set(req->limited, reg->index))
+                       continue;
+
+               copy = be_new_Copy(cls, block, op);
+               stat_ev_int("constr_copy", 1);
+               sched_add_before(node, copy);
+               set_irn_n(node, i, copy);
+               DBG((dbg, LEVEL_3, "inserting ignore arg copy %+F for %+F pos %d\n",
+                    copy, node, i));
        }
 
-       return ctx->spill;
-}
-
-/**
- * If the first usage of a phi result would be out of memory
- * there is no sense in allocating a register for it.
- * Thus we spill it and all its operands to the same spill slot.
- * Therefore the phi/dataB becomes a phi/Memory
- */
-static ir_node *be_spill_phi(spill_env_t *senv, ir_node *phi, ir_node *ctx_irn) {
-       int i, n = get_irn_arity(phi);
-       ir_node **ins, *bl = get_nodes_block(phi);
-       ir_graph *irg = senv->chordal_env->irg;
-       spill_ctx_t *ctx;
-
-       assert(is_Phi(phi));
-       DBG((senv->dbg, LEVEL_1, "%+F in ctx %+F\n", phi, ctx_irn));
-
-       /* search an existing spill for this context */
-       ctx = be_get_spill_ctx(senv->spill_ctxs, phi, ctx_irn);
-
-       /* if not found spill the phi */
-       if(!ctx->spill) {
-               /* build a new PhiM with dummy in-array */
-               NEW_ARR_A(ir_node *, ins, n);
-               for(i=0; i<n; ++i)
-                       ins[i] = new_r_Unknown(irg, mode_M);
-               ctx->spill = new_r_Phi(senv->chordal_env->irg, bl, n, ins, mode_M);
-
-               /* re-wire the phiM */
-               for(i=0; i<n; ++i) {
-                       ir_node *arg = get_irn_n(phi, i);
-                       ir_node *sub_res;
-
-                       if(is_Phi(arg) && pset_find_ptr(senv->mem_phis, arg))
-                               sub_res = be_spill_phi(senv, arg, ctx_irn);
-                       else
-                               sub_res = be_spill_irn(senv, arg, ctx_irn);
-
-                       set_irn_n(ctx->spill, i, sub_res);
+       /* insert copies for nodes that occur constrained more than once. */
+       for (i = 0; i < arity; ++i) {
+               ir_node                   *in;
+               ir_node                   *copy;
+               const arch_register_req_t *req;
+
+               req = arch_get_irn_register_req_in(node, i);
+               if (req->cls != cls)
+                       continue;
+
+               if (! (req->type & arch_register_req_type_limited))
+                       continue;
+
+               in = get_irn_n(node, i);
+               if (!arch_irn_consider_in_reg_alloc(cls, in))
+                       continue;
+
+               for (i2 = i + 1; i2 < arity; ++i2) {
+                       ir_node *in2;
+                       const arch_register_req_t *req2;
+
+                       req2 = arch_get_irn_register_req_in(node, i2);
+                       if (req2->cls != cls)
+                               continue;
+                       if (! (req2->type & arch_register_req_type_limited))
+                               continue;
+
+                       in2 = get_irn_n(node, i2);
+                       if (in2 != in)
+                               continue;
+
+                       /* if the constraint is the same, no copy is necessary
+                        * TODO generalise unequal but overlapping constraints */
+                       if (rbitsets_equal(req->limited, req2->limited, cls->n_regs))
+                               continue;
+
+                       copy = be_new_Copy(cls, block, in);
+                       stat_ev_int("constr_copy", 1);
+
+                       sched_add_before(node, copy);
+                       set_irn_n(node, i2, copy);
+                       DBG((dbg, LEVEL_3,
+                            "inserting multiple constr copy %+F for %+F pos %d\n",
+                            copy, node, i2));
                }
        }
-       return ctx->spill;
-}
-
-static ir_node *be_spill_node(spill_env_t *senv, ir_node *to_spill) {
-       ir_node *res;
-       if (pset_find_ptr(senv->mem_phis, to_spill))
-               res = be_spill_phi(senv, to_spill, to_spill);
-       else
-               res = be_spill_irn(senv, to_spill, to_spill);
 
-       return res;
-}
-
-static void phi_walker(ir_node *irn, void *env) {
-       spill_env_t *senv = env;
-       const arch_env_t *arch = senv->chordal_env->birg->main_env->arch_env;
+       /* collect all registers occurring in out constraints. */
+       be_foreach_definition(node, cls, def,
+               if (! (req_->type & arch_register_req_type_limited))
+                       continue;
+               if (def_constr == NULL) {
+                       rbitset_alloca(def_constr, cls->n_regs);
+               }
+               rbitset_or(def_constr, req_->limited, cls->n_regs);
+       );
 
-       if (is_Phi(irn) && arch_irn_has_reg_class(arch, irn, 0, senv->cls)
-                       && senv->is_mem_phi(irn, senv->data)) {
-               DBG((senv->dbg, LEVEL_1, "  %+F\n", irn));
-               pset_insert_ptr(senv->mem_phis, irn);
+       /* no output constraints => we're good */
+       if (def_constr == NULL) {
+               return;
        }
-}
-
-#ifdef REMAT
-
-#ifdef BUGGY_REMAT
-
-/**
- * Check if a spilled node could be rematerialized.
- *
- * @param senv      the spill environment
- * @param spill     the Spill node
- * @param spilled   the node that was spilled
- * @param reloader  a irn that requires a reload
- */
-static int check_remat_conditions(spill_env_t *senv, ir_node *spill, ir_node *spilled, ir_node *reloader) {
-       int pos, max;
-
-       /* check for 'normal' spill and general remat condition */
-       if (!be_is_Spill(spill) || !arch_irn_is(senv->chordal_env->birg->main_env->arch_env, spilled, rematerializable))
-               return 0;
 
-       /* check availability of original arguments */
-       if (is_Block(reloader)) {
-
-               /* we want to remat at the end of a block.
-                * thus all arguments must be alive at the end of the block
+       /*
+        * insert copies for all constrained arguments living through the node
+        * and being constrained to a register which also occurs in out constraints.
+        */
+       rbitset_alloca(tmp, cls->n_regs);
+       for (i = 0; i < arity; ++i) {
+               const arch_register_req_t *req;
+               ir_node                   *in;
+               ir_node                   *copy;
+
+               /*
+                * Check, if
+                * 1) the operand is constrained.
+                * 2) lives through the node.
+                * 3) is constrained to a register occurring in out constraints.
                 */
-               for (pos=0, max=get_irn_arity(spilled); pos<max; ++pos) {
-                       ir_node *arg = get_irn_n(spilled, pos);
-                       if (!is_live_end(reloader, arg))
-                               return 0;
-               }
-
-       } else {
-
-               /* we want to remat before the insn reloader
-                * thus an arguments is alive if
-                *   - it interferes with the reloaders result
-                * or
-                *   - or it is (last-) used by reloader itself
+               req = arch_get_irn_register_req_in(node, i);
+               if (req->cls != cls)
+                       continue;
+               if (!(req->type & arch_register_req_type_limited))
+                       continue;
+
+               in = get_irn_n(node, i);
+               if (!arch_irn_consider_in_reg_alloc(cls, in))
+                       continue;
+               if (!be_values_interfere(lv, node, in))
+                       continue;
+
+               rbitset_copy(tmp, req->limited, cls->n_regs);
+               rbitset_and(tmp, def_constr, cls->n_regs);
+
+               if (rbitset_is_empty(tmp, cls->n_regs))
+                       continue;
+
+               /*
+                * only create the copy if the operand is no copy.
+                * this is necessary since the assure constraints phase inserts
+                * Copies and Keeps for operands which must be different from the
+                * results. Additional copies here would destroy this.
                 */
-               for (pos=0, max=get_irn_arity(spilled); pos<max; ++pos) {
-                       ir_node *arg = get_irn_n(spilled, pos);
-                       int i, m;
-
-                       if (values_interfere(reloader, arg))
-                               goto is_alive;
-
-                       for (i=0, m=get_irn_arity(reloader); i<m; ++i) {
-                               ir_node *rel_arg = get_irn_n(reloader, i);
-                               if (rel_arg == arg)
-                                       goto is_alive;
-                       }
-
-                       /* arg is not alive before reloader */
-                       return 0;
-
-is_alive:      ;
-
-               }
-
+               if (be_is_Copy(in))
+                       continue;
+
+               copy = be_new_Copy(cls, block, in);
+               sched_add_before(node, copy);
+               set_irn_n(node, i, copy);
+               DBG((dbg, LEVEL_3, "inserting constr copy %+F for %+F pos %d\n",
+                    copy, node, i));
+               be_liveness_update(lv, in);
        }
-
-       return 1;
 }
 
-#else /* BUGGY_REMAT */
-
-/**
- * A very simple rematerialization checker.
- *
- * @param senv      the spill environment
- * @param spill     the Spill node
- * @param spilled   the node that was spilled
- * @param reloader  a irn that requires a reload
- */
-static int check_remat_conditions(spill_env_t *senv, ir_node *spill, ir_node *spilled, ir_node *reloader) {
-       const arch_env_t *aenv = senv->chordal_env->birg->main_env->arch_env;
-
-       return get_irn_arity(spilled) == 0 &&
-                  be_is_Spill(spill) &&
-                  arch_irn_is(aenv, spilled, rematerializable);
-}
-
-#endif /* BUGGY_REMAT */
-
-#endif /* REMAT */
-
-/**
- * Rematerialize a node.
- *
- * @param senv      the spill environment
- * @param spilled   the node that was spilled
- * @param reloader  a irn that requires a reload
- */
-static ir_node *do_remat(spill_env_t *senv, ir_node *spilled, ir_node *reloader) {
-       ir_node *res;
-       ir_node *bl = (is_Block(reloader)) ? reloader : get_nodes_block(reloader);
-
-       /* recompute the value */
-       res = new_ir_node(get_irn_dbg_info(spilled), senv->chordal_env->irg, bl,
-               get_irn_op(spilled),
-               get_irn_mode(spilled),
-               get_irn_arity(spilled),
-               get_irn_in(spilled) + 1);
-       copy_node_attr(spilled, res);
-
-       DBG((senv->dbg, LEVEL_1, "Insert remat %+F before reloader %+F\n", res, reloader));
-
-       /* insert in schedule */
-       if (is_Block(reloader)) {
-               ir_node *insert = sched_skip(reloader, 0, sched_skip_cf_predicator, (void *) senv->chordal_env->birg->main_env->arch_env);
-               sched_add_after(insert, res);
-       } else {
-               sched_add_before(reloader, res);
+static void pre_spill_prepare_constr_walker(ir_node *block, void *data)
+{
+       be_pre_spill_env_t *env = (be_pre_spill_env_t*)data;
+       ir_node *node;
+       sched_foreach(block, node) {
+               prepare_constr_insn(env, node);
        }
-
-       return res;
 }
 
-void be_insert_spills_reloads(spill_env_t *senv, pset *reload_set) {
-       const arch_env_t *aenv = senv->chordal_env->birg->main_env->arch_env;
-       ir_graph *irg          = senv->chordal_env->irg;
-       ir_node *irn;
-       spill_info_t *si;
-       pdeq *possibly_dead;
-
-       /* get all special spilled phis */
-       DBG((senv->dbg, LEVEL_1, "Mem-phis:\n"));
-       senv->mem_phis = pset_new_ptr_default();
-       irg_walk_graph(senv->chordal_env->irg, phi_walker, NULL, senv);
-
-       /* Add reloads for mem_phis */
-       /* BETTER: These reloads (1) should only be inserted, if they are really needed */
-       DBG((senv->dbg, LEVEL_1, "Reloads for mem-phis:\n"));
-       for(irn = pset_first(senv->mem_phis); irn; irn = pset_next(senv->mem_phis)) {
-               const ir_edge_t *e;
-               DBG((senv->dbg, LEVEL_1, " Mem-phi %+F\n", irn));
-               foreach_out_edge(irn, e) {
-                       ir_node *user = e->src;
-                       if (is_Phi(user) && !pset_find_ptr(senv->mem_phis, user)) {
-                                       ir_node *use_bl = get_nodes_block(user);
-                                       DBG((senv->dbg, LEVEL_1, " non-mem-phi user %+F\n", user));
-                                       be_add_reload_on_edge(senv, irn, use_bl, e->pos); /* (1) */
-                       }
-               }
-       }
-
-       /* process each spilled node */
-       DBG((senv->dbg, LEVEL_1, "Insert spills and reloads:\n"));
-       possibly_dead = new_pdeq();
-       for(si = set_first(senv->spills); si; si = set_next(senv->spills)) {
-               reloader_t *rld;
-               ir_mode *mode = get_irn_mode(si->spilled_node);
-               pset *values = pset_new_ptr(16);
-
-               /* go through all reloads for this spill */
-               for(rld = si->reloaders; rld; rld = rld->next) {
-                       ir_node *new_val;
-
-                       /* the spill for this reloader */
-                       ir_node *spill   = be_spill_node(senv, si->spilled_node);
-
-#ifdef REMAT
-                       if (check_remat_conditions(senv, spill, si->spilled_node, rld->reloader)) {
-                               new_val = do_remat(senv, si->spilled_node, rld->reloader);
-                               pdeq_putl(possibly_dead, spill);
-                       }
-                       else
-#endif
-                               /* do a reload */
-                               new_val = be_reload(aenv, senv->cls, rld->reloader, mode, spill);
-
-                       DBG((senv->dbg, LEVEL_1, " %+F of %+F before %+F\n", new_val, si->spilled_node, rld->reloader));
-                       pset_insert_ptr(values, new_val);
-                       if(reload_set)
-                               pset_insert_ptr(reload_set, new_val);
-               }
+void be_pre_spill_prepare_constr(ir_graph *irg,
+                                 const arch_register_class_t *cls)
+{
+       be_pre_spill_env_t env;
+       memset(&env, 0, sizeof(env));
+       env.irg = irg;
+       env.cls = cls;
 
-               /* introduce copies, rewire the uses */
-               assert(pset_count(values) > 0 && "???");
-               pset_insert_ptr(values, si->spilled_node);
-               be_ssa_constr_set_ignore(senv->chordal_env->dom_front, values, senv->mem_phis);
+       be_assure_liveness(irg);
 
-               del_pset(values);
-       }
-
-       foreach_pset(senv->mem_phis, irn) {
-               int i, n;
-               for (i = 0, n = get_irn_arity(irn); i < n; ++i) {
-                       pdeq_putl(possibly_dead, get_irn_n(irn, i));
-                       set_irn_n(irn, i, new_r_Bad(senv->chordal_env->irg));
-               }
-               sched_remove(irn);
-       }
-
-       /* check if possibly dead nodes are really dead yet */
-       while (! pdeq_empty(possibly_dead)) {
-               ir_node *irn = pdeq_getr(possibly_dead);
-               const ir_edge_t *edge = get_irn_out_edge_first(irn);
-
-               if (! edge) {
-                       int i;
-                       for (i = get_irn_arity(irn) - 1; i >= 0; --i) {
-                               pdeq_putl(possibly_dead, get_irn_n(irn, i));
-                               set_irn_n(irn, i, new_r_Bad(senv->chordal_env->irg));
-                       }
-                       sched_remove(irn);
-               }
-       }
-       del_pdeq(possibly_dead);
-       del_pset(senv->mem_phis);
-}
-
-void be_add_reload(spill_env_t *senv, ir_node *to_spill, ir_node *before) {
-       spill_info_t templ, *res;
-       reloader_t *rel;
-
-       templ.spilled_node = to_spill;
-       templ.reloaders    = NULL;
-       res = set_insert(senv->spills, &templ, sizeof(templ), HASH_PTR(to_spill));
-
-       rel           = obstack_alloc(&senv->obst, sizeof(rel[0]));
-       rel->reloader = before;
-       rel->next     = res->reloaders;
-       res->reloaders = rel;
-}
-
-void be_add_reload_on_edge(spill_env_t *senv, ir_node *to_spill, ir_node *bl, int pos) {
-       ir_node *insert_bl = get_irn_arity(bl) == 1 ? sched_first(bl) : get_Block_cfgpred_block(bl, pos);
-       be_add_reload(senv, to_spill, insert_bl);
+       irg_block_walk_graph(irg, pre_spill_prepare_constr_walker, NULL, &env);
 }
 
 
 
-/****************************************
-
-       SPILL SLOT MANAGEMENT AND OPTS
-
-****************************************/
-
-typedef struct _spill_slot_t {
-       unsigned size;
-       unsigned align;
-       pset *members;
-       ir_mode *largest_mode;  /* the mode of all members with largest size */
-} spill_slot_t;
+int be_coalesce_spill_slots = 1;
+int be_do_remats = 1;
 
-typedef struct _ss_env_t {
-       struct obstack ob;
-       be_chordal_env_t *cenv;
-       pmap *slots;            /* maps spill_contexts to spill_slots */
-       pmap *types;    /* maps modes to types */
-       DEBUG_ONLY(firm_dbg_module_t *dbg;)
-} ss_env_t;
-
-
-/**
- * Walker: compute the spill slots
- */
-static void compute_spill_slots_walker(ir_node *spill, void *env) {
-       ss_env_t *ssenv = env;
-       ir_node *ctx;
-       pmap_entry *entry;
-       spill_slot_t *ss;
-
-       if (!be_is_Spill(spill))
-               return;
-
-       /* check, if this spill is for a context already known */
-       ctx = be_get_Spill_context(spill);
-       entry = pmap_find(ssenv->slots, ctx);
-
-       if (!entry) {
-               struct _arch_env_t *arch_env     = ssenv->cenv->birg->main_env->arch_env;
-               const arch_register_class_t *cls = arch_get_irn_reg_class(arch_env, spill, be_pos_Spill_val);
-               ir_mode *largest_mode            = arch_register_class_mode(cls);
-
-               /* this is a new spill context */
-               ss = obstack_alloc(&ssenv->ob, sizeof(*ss));
-               ss->members      = pset_new_ptr(8);
-               ss->largest_mode = largest_mode;
-               ss->size         = get_mode_size_bytes(ss->largest_mode);
-               ss->align        = arch_isa_get_reg_class_alignment(arch_env->isa, cls);
-               pmap_insert(ssenv->slots, ctx, ss);
-       } else {
-               /* values with the same spill_ctx must go into the same spill slot */
-               ss = entry->value;
-
-#ifndef NDEBUG
-               /* ugly mega assert :-) */
-               {
-                       ir_node *irn;
-                       struct _arch_env_t *arch_env     = ssenv->cenv->birg->main_env->arch_env;
-                       const arch_register_class_t *cls = arch_get_irn_reg_class(arch_env, spill, be_pos_Spill_val);
-                       int size = get_mode_size_bytes(arch_register_class_mode(cls));
-                       assert(ss->size == size && "Different sizes for the same spill slot are not allowed.");
-                       for (irn = pset_first(ss->members); irn; irn = pset_next(ss->members)) {
-                               /* use values_interfere here, because it uses the dominance check,
-                                        which does work for values in memory */
-                               assert(!values_interfere(spill, irn) && "Spills for the same spill slot must not interfere!");
-                       }
-               }
-#endif /* NDEBUG */
-       }
-
-       pset_insert_ptr(ss->members, spill);
-}
-
-/**
- * qsort compare function, sort spill slots by size.
- */
-static int ss_sorter(const void *v1, const void *v2) {
-       const spill_slot_t *ss1 = v1;
-       const spill_slot_t *ss2 = v2;
-       return ((int) ss2->size) - ((int) ss1->size);
-}
-
-
-/**
- * This function should optimize the spill slots.
- *  - Coalescing of multiple slots
- *  - Ordering the slots
- *
- * Input slots are in @p ssenv->slots
- * @p size The count of initial spill slots in @p ssenv->slots
- *         This also is the size of the preallocated array @p ass
- *
- * @return An array of spill slots @p ass in specific order
- **/
-static void optimize_slots(ss_env_t *ssenv, int size, spill_slot_t **ass) {
-       int i, o, used_slots;
-       pmap_entry *entr;
-
-       i=0;
-       pmap_foreach(ssenv->slots, entr)
-               ass[i++] = entr->value;
-
-       /* Sort the array to minimize fragmentation and cache footprint.
-          Large slots come first */
-       qsort(ass, size, sizeof(ass[0]), ss_sorter);
-
-       /* For each spill slot:
-               - assign a new offset to this slot
-           - xor find another slot to coalesce with */
-       used_slots = 0;
-       for (i=0; i<size; ++i) { /* for each spill slot */
-               ir_node *n1;
-               int tgt_slot = -1;
-
-               DBG((ssenv->dbg, LEVEL_1, "Spill slot %d members:\n", i));
-               for(n1 = pset_first(ass[i]->members); n1; n1 = pset_next(ass[i]->members))
-                       DBG((ssenv->dbg, LEVEL_1, "  %+F\n", n1));
-
-
-               for (o=0; o < used_slots && tgt_slot == -1; ++o) { /* for each offset-assigned spill slot */
-                       /* check inter-slot-pairs for interference */
-                       ir_node *n2;
-                       for(n1 = pset_first(ass[i]->members); n1; n1 = pset_next(ass[i]->members))
-                               for(n2 = pset_first(ass[o]->members); n2; n2 = pset_next(ass[o]->members))
-                                       if(values_interfere(n1, n2)) {
-                                               pset_break(ass[i]->members);
-                                               pset_break(ass[o]->members);
-                                               DBG((ssenv->dbg, LEVEL_1, "    Interf %+F -- %+F\n", n1, n2));
-                                               goto interf_detected;
-                                       }
-
-                       /* if we are here, there is no interference between ass[i] and ass[o] */
-                       tgt_slot = o;
-
-interf_detected: /*nothing*/ ;
-               }
-
-               /* now the members of ass[i] join the members of ass[tgt_slot] */
-
-               /* do we need a new slot? */
-               if (tgt_slot == -1) {
-                       tgt_slot = used_slots;
-                       used_slots++;
+static const lc_opt_table_entry_t be_spill_options[] = {
+       LC_OPT_ENT_BOOL ("coalesce_slots", "coalesce the spill slots", &be_coalesce_spill_slots),
+       LC_OPT_ENT_BOOL ("remat", "try to rematerialize values instead of reloading", &be_do_remats),
+       LC_OPT_LAST
+};
 
-                       /* init slot */
-                       if (tgt_slot != i) {
-                               ass[tgt_slot]->size = ass[i]->size;
-                               del_pset(ass[tgt_slot]->members);
-                               ass[tgt_slot]->members = pset_new_ptr(8);
-                       }
-               }
+static be_module_list_entry_t *spillers = NULL;
+static const be_spiller_t *selected_spiller = NULL;
 
-               /* copy the members to the target pset */
-               /* NOTE: If src and tgt pset are the same, inserting while iterating is not allowed */
-               if (tgt_slot != i)
-                       for(n1 = pset_first(ass[i]->members); n1; n1 = pset_next(ass[i]->members))
-                                       pset_insert_ptr(ass[tgt_slot]->members, n1);
-       }
+void be_register_spiller(const char *name, be_spiller_t *spiller)
+{
+       if (selected_spiller == NULL)
+               selected_spiller = spiller;
+       be_add_module_to_list(&spillers, name, spiller);
 }
 
-#define ALIGN_SPILL_AREA 16
-#define pset_foreach(pset, elm)  for(elm=pset_first(pset); elm; elm=pset_next(pset))
+void be_do_spill(ir_graph *irg, const arch_register_class_t *cls)
+{
+       assert(selected_spiller != NULL);
 
-/**
- * Returns a spill type for a mode. Keep them in a map to reduce
- * the number of types.
- *
- * @param types  a map containing all created types
- * @param ss     the spill slot
- *
- * Note that type types should are identical for every mode.
- * This rule might break if two different register classes return the same
- * mode but different alignments.
- */
-static ir_type *get_spill_type(pmap *types, spill_slot_t *ss) {
-  pmap_entry *e = pmap_find(types, ss->largest_mode);
-  ir_type *res;
-
-  if (! e) {
-               char buf[64];
-    snprintf(buf, sizeof(buf), "spill_slot_type_%s", get_mode_name(ss->largest_mode));
-    res = new_type_primitive(new_id_from_str(buf), ss->largest_mode);
-               set_type_alignment_bytes(res, ss->align);
-    pmap_insert(types, ss->largest_mode, res);
-  }
-  else {
-    res = e->value;
-               assert(get_type_alignment_bytes(res) == (int)ss->align);
-       }
-  return res;
+       selected_spiller->spill(irg, cls);
 }
 
-/**
- * Create spill slot entities on the frame type.
- *
- * @param ssenv   the spill environment
- * @param n       number of spill slots
- * @param ss      array of spill slots
- */
-static void assign_entities(ss_env_t *ssenv, int n_slots, spill_slot_t *ss[]) {
-       int i, offset, frame_align;
-       ir_type *frame = get_irg_frame_type(ssenv->cenv->irg);
-
-       /* aligning by increasing frame size */
-       offset = get_type_size_bits(frame) / 8;
-       offset = round_up2(offset, ALIGN_SPILL_AREA);
-       set_type_size_bytes(frame, -1);
-
-       /* create entities and assign offsets according to size and alignment*/
-       for (i = 0; i < n_slots; ++i) {
-               char buf[64];
-               ident *name;
-               entity *spill_ent;
-               ir_node *irn;
-
-               /* build entity */
-               snprintf(buf, sizeof(buf), "spill_slot_%d", i);
-               name = new_id_from_str(buf);
-
-               spill_ent = new_entity(frame, name, get_spill_type(ssenv->types, ss[i]));
-
-               /* align */
-               offset = round_up2(offset, ss[i]->align);
-               /* set */
-               set_entity_offset_bytes(spill_ent, offset);
-               /* next possible offset */
-               offset += round_up2(ss[i]->size, ss[i]->align);
-
-               pset_foreach(ss[i]->members, irn)
-                       be_set_Spill_entity(irn, spill_ent);
-       }
+BE_REGISTER_MODULE_CONSTRUCTOR(be_init_spilloptions)
+void be_init_spilloptions(void)
+{
+       lc_opt_entry_t *be_grp = lc_opt_get_grp(firm_opt_get_root(), "be");
+       lc_opt_entry_t *spill_grp = lc_opt_get_grp(be_grp, "spill");
 
-       /* set final size of stack frame */
-       frame_align = get_type_alignment_bytes(frame);
-       set_type_size_bytes(frame, round_up2(offset, frame_align));
-}
+       lc_opt_add_table(spill_grp, be_spill_options);
+       be_add_module_list_opt(be_grp, "spiller", "spill algorithm",
+                              &spillers, (void**) &selected_spiller);
 
-void be_compute_spill_offsets(be_chordal_env_t *cenv) {
-       ss_env_t ssenv;
-       spill_slot_t **ss;
-       int ss_size;
-       pmap_entry *pme;
-
-       obstack_init(&ssenv.ob);
-       ssenv.cenv  = cenv;
-       ssenv.slots = pmap_create();
-       ssenv.types = pmap_create();
-       FIRM_DBG_REGISTER(ssenv.dbg, "ir.be.spillslots");
-
-       /* Get initial spill slots */
-       irg_walk_graph(cenv->irg, NULL, compute_spill_slots_walker, &ssenv);
-
-       /* Build an empty array for optimized spill slots */
-       ss_size = pmap_count(ssenv.slots);
-       ss = obstack_alloc(&ssenv.ob, ss_size * sizeof(*ss));
-       optimize_slots(&ssenv, ss_size, ss);
-
-       /* Integrate slots into the stack frame entity */
-       assign_entities(&ssenv, ss_size, ss);
-
-       /* Clean up */
-       pmap_foreach(ssenv.slots, pme)
-       del_pset(((spill_slot_t *)pme->value)->members);
-       pmap_destroy(ssenv.slots);
-       pmap_destroy(ssenv.types);
-       obstack_free(&ssenv.ob, NULL);
-
-       be_copy_entities_to_reloads(cenv->irg);
+       FIRM_DBG_REGISTER(dbg, "firm.be.spillprepare");
 }