--- /dev/null
+/*
+ * 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 Linear Scan Spill algorithm
+ * @author Matthias Braun
+ * @date 20.09.2005
+ * @version $Id$
+ */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "irnode_t.h"
+#include "irprintf.h"
+#include "iredges_t.h"
+
+#include "bemodule.h"
+#include "besched_t.h"
+#include "bespilloptions.h"
+#include "bespill.h"
+#include "benode_t.h"
+#include "be_t.h"
+#include "belive_t.h"
+
+/* a place in the program */
+typedef struct place_t {
+ unsigned block_nr;
+ int timestep;
+} place_t;
+
+typedef struct interval_t {
+ ir_node *value;
+ double spill_costs;
+ place_t begin;
+ place_t end;
+} interval_t;
+
+static interval_t **intervals;
+
+DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
+
+static struct obstack obst;
+static const arch_env_t *arch_env;
+static const arch_register_class_t *cls;
+static spill_env_t *spill_env;
+static unsigned n_regs;
+static const be_lv_t *lv;
+
+static double get_spill_costs(ir_node *node)
+{
+ const ir_edge_t *edge;
+ ir_node *spill_place = skip_Proj(node);
+ double costs = be_get_spill_costs(spill_env, node,
+ spill_place);
+ foreach_out_edge(node, edge) {
+ ir_node *use = get_edge_src_irn(edge);
+
+ /* keeps should be directly below the node */
+ if(be_is_Keep(use)) {
+ continue;
+ }
+
+ if(is_Phi(use)) {
+ int in = get_edge_src_pos(edge);
+ ir_node *block = get_nodes_block(use);
+
+ costs += be_get_reload_costs_on_edge(spill_env, node, block, in);
+ } else {
+ costs += be_get_reload_costs(spill_env, node, use);
+ }
+ }
+
+ return costs;
+}
+
+/**
+ * spills a node by placing a reload before each usage
+ */
+static void spill_node(ir_node *node)
+{
+ const ir_edge_t *edge;
+
+ DBG((dbg, LEVEL_3, "\tspilling %+F\n", node));
+
+ foreach_out_edge(node, edge) {
+ ir_node *use = get_edge_src_irn(edge);
+ if(is_Anchor(use))
+ continue;
+ if(be_is_Keep(use))
+ continue;
+
+ if(is_Phi(use)) {
+ int in = get_edge_src_pos(edge);
+ ir_node *block = get_nodes_block(use);
+
+ be_add_reload_on_edge(spill_env, node, block, in, cls, 1);
+ } else {
+ be_add_reload(spill_env, node, use, cls, 1);
+ }
+ }
+}
+
+
+static int place_less(const place_t *place1, const place_t *place2)
+{
+ if(place1->block_nr < place2->block_nr)
+ return 1;
+ if(place1->block_nr > place2->block_nr)
+ return 0;
+
+ return place1->timestep < place2->timestep;
+}
+
+static int place_equal(const place_t *place1, const place_t *place2)
+{
+ return place1->block_nr == place2->block_nr
+ && place1->timestep == place2->timestep;
+}
+
+static void extend_interval(ir_node *value, const place_t *place)
+{
+ interval_t *interval;
+
+ if(!irn_visited(value)) {
+ interval = obstack_alloc(&obst, sizeof(interval[0]));
+ interval->begin = *place;
+ interval->end = *place;
+ interval->value = value;
+ interval->spill_costs = 0;
+
+ ARR_APP1(interval_t*, intervals, interval);
+
+ set_irn_link(value, interval);
+ mark_irn_visited(value);
+ } else {
+ interval = get_irn_link(value);
+
+ if(place_less(place, &interval->begin)) {
+ interval->begin = *place;
+ }
+ if(place_less(&interval->end, place)) {
+ interval->end = *place;
+ }
+ }
+}
+
+/**
+ * link live intervals to values, put all intervals into a list,
+ * sort the list. We process the blocks in a toplogical order (by ignoring
+ * backedges).
+ */
+static void calculate_liveness_intervals(ir_node *block, unsigned block_nr)
+{
+ ir_node *node;
+ int i, arity;
+ place_t place;
+
+ set_irn_link(block, INT_TO_PTR(block_nr));
+
+ place.block_nr = block_nr;
+ place.timestep = 0;
+
+ be_lv_foreach(lv, block, be_lv_state_in, i) {
+ ir_node *node = be_lv_get_irn(lv, block, i);
+ if(!arch_irn_consider_in_reg_alloc(arch_env, cls, node))
+ continue;
+
+ extend_interval(node, &place);
+ }
+
+ sched_foreach_reverse(block, node) {
+
+ if(is_Phi(node))
+ break;
+
+ place.timestep = sched_get_time_step(node);
+
+ if(get_irn_mode(node) == mode_T) {
+ const ir_edge_t *edge;
+
+ foreach_out_edge(node, edge) {
+ ir_node *proj = get_edge_src_irn(edge);
+ if(arch_irn_consider_in_reg_alloc(arch_env, cls, proj)) {
+ extend_interval(proj, &place);
+ }
+ }
+ } else if(arch_irn_consider_in_reg_alloc(arch_env, cls, node)) {
+ extend_interval(node, &place);
+ }
+
+ arity = get_irn_arity(node);
+ for(i = 0; i < arity; ++i) {
+ ir_node *op = get_irn_n(node, i);
+
+ if(arch_irn_consider_in_reg_alloc(arch_env, cls, op)) {
+ extend_interval(op, &place);
+ }
+ }
+ }
+
+ place.timestep++;
+ be_lv_foreach(lv, block, be_lv_state_end, i) {
+ ir_node *node = be_lv_get_irn(lv, block, i);
+ if(!arch_irn_consider_in_reg_alloc(arch_env, cls, node))
+ continue;
+
+ extend_interval(node, &place);
+ }
+
+ ir_printf("processing block %+F(%u)\n", block, block_nr);
+}
+
+static unsigned next_block_nr;
+
+/**
+ * process blocks in a toplogical order (we ignore backedges and create a
+ * topological order from the remaining edges)
+ */
+static void process_block(ir_node *block)
+{
+ unsigned block_nr;
+ int n_preds;
+ int i;
+
+ if(irn_visited(block))
+ return;
+ mark_irn_visited(block);
+
+ n_preds = get_Block_n_cfgpreds(block);
+ for(i = 0; i < n_preds; ++i) {
+ ir_node *pred_block;
+
+ if(is_backedge(block, i))
+ continue;
+
+ pred_block = get_Block_cfgpred_block(block, i);
+ process_block(pred_block);
+ }
+
+ block_nr = next_block_nr;
+ next_block_nr++;
+ calculate_liveness_intervals(block, block_nr);
+}
+
+static void print_interval(const interval_t *interval)
+{
+ ir_fprintf(stderr, "%+F [%u,%d] -> [%u,%d]\n", interval->value,
+ interval->begin.block_nr, interval->begin.timestep,
+ interval->end.block_nr, interval->end.timestep);
+}
+
+static int compare_spill_costs(const void *d1, const void *d2)
+{
+ const interval_t *interval1 = *((const interval_t**)d1);
+ const interval_t *interval2 = *((const interval_t**)d2);
+ if(interval2->spill_costs < interval1->spill_costs)
+ return -1;
+ return 1;
+}
+
+static void do_spilling(void)
+{
+ interval_t **live_intervals;
+ unsigned n_live_intervals;
+ interval_t **intervals_to_allocate;
+ unsigned n_intervals_to_allocate;
+
+ live_intervals = alloca(n_regs * sizeof(live_intervals[0]));
+ n_live_intervals = 0;
+ intervals_to_allocate = alloca(n_regs * sizeof(intervals_to_allocate[0]));
+
+ int i;
+ int len = ARR_LEN(intervals);
+ for(i = 0; i < len; ) {
+ const place_t place = intervals[i]->begin;
+
+ n_intervals_to_allocate = 0;
+ do {
+ interval_t *interval = intervals[i];
+
+ print_interval(interval);
+
+ intervals_to_allocate[n_intervals_to_allocate] = intervals[i];
+ ++n_intervals_to_allocate;
+ ++i;
+ } while(i < len && place_equal(&intervals[i]->begin, &place));
+
+ int spills_needed = n_live_intervals + n_intervals_to_allocate - n_regs;
+
+ /* first expire intervals whose endpoint is above our current place */
+ if(spills_needed > 0) {
+ unsigned a;
+
+ for(a = 0; a < n_live_intervals; ) {
+ interval_t *live_interval = live_intervals[a];
+ if(place_less(&place, &live_interval->end)) {
+ ++a;
+ } else {
+ fprintf(stderr, "expired: ");
+ print_interval(live_interval);
+ live_intervals[a] = live_intervals[n_live_intervals-1];
+ --n_live_intervals;
+ }
+ }
+
+ spills_needed = n_live_intervals + n_intervals_to_allocate - n_regs;
+ }
+ /* spill intervals */
+ if(spills_needed > 0) {
+ ir_fprintf(stderr, "need to spill %d values at %u,%d\n",
+ spills_needed, place.block_nr, place.timestep);
+
+ unsigned a;
+ for(a = 0; a < n_live_intervals; ++a) {
+ interval_t *live_interval = live_intervals[a];
+ if(live_interval->spill_costs == 0) {
+ ir_node *value = live_interval->value;
+ live_interval->spill_costs = get_spill_costs(value);
+ ir_fprintf(stderr, "spillcosts for %+F: %f\n", value,
+ live_interval->spill_costs);
+ }
+ }
+
+ qsort(live_intervals, n_live_intervals, sizeof(live_intervals[0]),
+ compare_spill_costs);
+
+ a = n_live_intervals - spills_needed;
+ for( ; a < n_live_intervals; ++a) {
+ const interval_t *live_interval = live_intervals[a];
+ ir_node *value = live_interval->value;
+
+ ir_fprintf(stderr, "spilling %+F (%f)\n", value, live_interval->spill_costs);
+ spill_node(value);
+ }
+ n_live_intervals -= spills_needed;
+ }
+
+ assert(n_regs - n_live_intervals >= n_intervals_to_allocate);
+
+ unsigned a;
+ for(a = 0; a < n_intervals_to_allocate; ++a) {
+ live_intervals[n_live_intervals] = intervals_to_allocate[a];
+ ++n_live_intervals;
+ }
+ assert(n_live_intervals <= n_regs);
+ }
+}
+
+static int cmp_interval(const void *d1, const void *d2)
+{
+ const interval_t *interval1 = *((const interval_t**) d1);
+ const interval_t *interval2 = *((const interval_t**) d2);
+
+ return !place_less(&interval1->begin, &interval2->begin);
+}
+
+static void be_spill_linearscan(be_irg_t *birg,
+ const arch_register_class_t *new_cls)
+{
+ size_t n_intervals;
+ ir_node *end_block;
+ ir_graph *irg = be_get_birg_irg(birg);
+
+ be_liveness_assure_sets(be_assure_liveness(birg));
+
+ arch_env = be_get_birg_arch_env(birg);
+ cls = new_cls;
+ intervals = NEW_ARR_F(interval_t*, 0);
+ spill_env = be_new_spill_env(birg);
+ lv = be_get_birg_liveness(birg);
+ n_regs = cls->n_regs - be_put_ignore_regs(birg, new_cls, NULL);
+
+ obstack_init(&obst);
+
+ set_using_visited(irg);
+ set_using_irn_link(irg);
+ inc_irg_visited(irg);
+
+ next_block_nr = 0;
+
+ /* use toposort for liveness analysis */
+ end_block = get_irg_end_block(irg);
+ process_block(end_block);
+
+ assert(irn_visited(get_irg_start_block(irg)));
+
+ n_intervals = ARR_LEN(intervals);
+ qsort(intervals, n_intervals, sizeof(intervals[0]), cmp_interval);
+
+ do_spilling();
+
+ clear_using_visited(irg);
+ clear_using_irn_link(irg);
+
+ DEL_ARR_F(intervals);
+ obstack_free(&obst, NULL);
+
+ /* Insert spill/reload nodes into the graph and fix usages */
+ be_insert_spills_reloads(spill_env);
+
+ be_delete_spill_env(spill_env);
+ spill_env = NULL;
+}
+
+void be_init_spilllinearscan(void)
+{
+ static be_spiller_t spiller = {
+ be_spill_linearscan
+ };
+
+ be_register_spiller("linearscan", &spiller);
+ FIRM_DBG_REGISTER(dbg, "firm.be.spill.linearscan");
+}
+
+BE_REGISTER_MODULE_CONSTRUCTOR(be_init_spilllinearscan);
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