/*
- * Copyright (C) 1995-2007 University of Karlsruhe. All right reserved.
+ * Copyright (C) 1995-2011 University of Karlsruhe. All right reserved.
*
* This file is part of libFirm.
*
/**
* @file
- * @brief Naiv spilling algorithm
+ * @brief Naive spilling algorithm
* @author Matthias Braun
* @date 20.09.2005
- * @version $Id: bespillbelady.c 13913 2007-05-18 12:48:56Z matze $
- * @summary
- * This implements a naiv spilling algorithm. It is design to produce similar
- * effects to the spill decisions produced by traditional graph coloring
- * register allocators that spill while they are coloring the graph.
+ * @brief
+ * This implements a naive spilling algorithm. It is designed to produce
+ * similar effects to the spill decisions produced by traditional graph
+ * coloring register allocators that spill while they are coloring the graph.
*
* This spiller walks over all blocks and looks for places with too high
* register pressure where it spills the values that are cheapest to spill.
* Spilling in this context means placing a spill instruction behind the
* definition of the value and a reload before each usage.
*/
-#ifdef HAVE_CONFIG_H
#include "config.h"
-#endif
#include "debug.h"
#include "error.h"
#include "beirg.h"
-#include "bespilloptions.h"
#include "bespill.h"
+#include "bespillutil.h"
#include "bemodule.h"
#include "besched.h"
-#include "bearch_t.h"
+#include "bearch.h"
#include "be_t.h"
-#include "benode_t.h"
-#include "beirg.h"
+#include "benode.h"
+#include "belive.h"
DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
-typedef struct daemel_env_t daemel_env_t;
-struct daemel_env_t {
- spill_env_t *spill_env;
- int n_regs;
- const arch_env_t *arch_env;
- const arch_register_class_t *cls;
- const be_lv_t *lv;
- bitset_t *spilled_nodes;
-};
+static spill_env_t *spill_env;
+static unsigned n_regs;
+static const arch_register_class_t *cls;
+static const be_lv_t *lv;
+static bitset_t *spilled_nodes;
typedef struct spill_candidate_t spill_candidate_t;
struct spill_candidate_t {
ir_node *node;
};
-static
-int compare_spill_candidates_desc(const void *d1, const void *d2)
+static int compare_spill_candidates_desc(const void *d1, const void *d2)
{
- const spill_candidate_t *c1 = d1;
- const spill_candidate_t *c2 = d2;
+ const spill_candidate_t *c1 = (const spill_candidate_t*)d1;
+ const spill_candidate_t *c2 = (const spill_candidate_t*)d2;
return (int) (c1->costs - c2->costs);
}
-static
-double get_spill_costs(daemel_env_t *env, ir_node *node)
+static double get_spill_costs(ir_node *node)
{
- const ir_edge_t *edge;
- spill_env_t *spill_env = env->spill_env;
- double costs = be_get_spill_costs(spill_env, node, node);
+ 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);
- if(is_Phi(use)) {
- int in = get_edge_src_pos(edge);
- ir_node *block = get_nodes_block(use);
+ /* 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 {
/**
* spills a node by placing a reload before each usage
*/
-static
-void spill_node(daemel_env_t *env, ir_node *node, ir_nodeset_t *nodes)
+static void spill_node(ir_node *node)
{
- const ir_edge_t *edge;
- spill_env_t *spill_env = env->spill_env;
- const arch_register_class_t *cls = env->cls;
-
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);
+ 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 if(!be_is_Keep(use)) {
+ } else {
be_add_reload(spill_env, node, use, cls, 1);
}
}
- bitset_set(env->spilled_nodes, get_irn_idx(node));
- ir_nodeset_remove(nodes, node);
+ bitset_set(spilled_nodes, get_irn_idx(node));
+}
+
+static unsigned get_value_width(const ir_node *node)
+{
+ const arch_register_req_t *req = arch_get_irn_register_req(node);
+ return req->width;
}
/**
* spill @p n nodes from a nodeset. Removes the nodes from the nodeset and
- * sets the spilled bits in env->spilled_nodes.
+ * sets the spilled bits in spilled_nodes.
*/
-static
-void do_spilling(daemel_env_t *env, ir_nodeset_t *nodes, ir_node *node,
- ir_node *spill_phis_in)
+static void do_spilling(ir_nodeset_t *live_nodes, ir_node *node)
{
- size_t node_count = ir_nodeset_size(nodes);
- size_t additional_defines = 0;
- int registers = env->n_regs;
- const arch_env_t *arch_env = env->arch_env;
- const arch_register_class_t *cls = env->cls;
- spill_candidate_t *candidates;
- ir_nodeset_iterator_t iter;
- size_t i, arity;
- int spills_needed;
- size_t cand_idx;
- ir_node *n;
-
- /* mode_T nodes define several values at once. Count them */
- if(get_irn_mode(node) == mode_T) {
- ir_node *proj = sched_next(node);
-
- while(is_Proj(proj)) {
- if(arch_irn_consider_in_reg_alloc(arch_env, cls, proj)) {
- ++additional_defines;
- }
- proj = sched_next(proj);
+ size_t values_defined = 0;
+ be_foreach_definition(node, cls, value,
+ (void)value;
+ assert(req_->width >= 1);
+ values_defined += req_->width;
+ );
+
+ /* we need registers for the non-live argument values */
+ size_t free_regs_needed = 0;
+ be_foreach_use(node, cls, in_req_, use, pred_req_,
+ if (!ir_nodeset_contains(live_nodes, use)) {
+ free_regs_needed += get_value_width(use);
}
- }
+ );
+
+ /* we can reuse all reloaded values for the defined values, but we might
+ * need even more registers */
+ if (values_defined > free_regs_needed)
+ free_regs_needed = values_defined;
- spills_needed = (node_count + additional_defines) - registers;
- if(spills_needed <= 0)
+ size_t n_live_nodes = ir_nodeset_size(live_nodes);
+ int spills_needed = (n_live_nodes + free_regs_needed) - n_regs;
+ if (spills_needed <= 0)
return;
DBG((dbg, LEVEL_2, "\tspills needed after %+F: %d\n", node, spills_needed));
- candidates = malloc(node_count * sizeof(candidates[0]));
+ spill_candidate_t *candidates = ALLOCAN(spill_candidate_t, n_live_nodes);
/* construct array with spill candidates and calculate their costs */
- i = 0;
- foreach_ir_nodeset(nodes, n, iter) {
- spill_candidate_t *candidate = & candidates[i];
+ size_t c = 0;
+ foreach_ir_nodeset(live_nodes, n, iter) {
+ spill_candidate_t *candidate = & candidates[c];
+
+ assert(!bitset_is_set(spilled_nodes, get_irn_idx(n)));
candidate->node = n;
- candidate->costs = get_spill_costs(env, n);
- ++i;
+ candidate->costs = get_spill_costs(n);
+ ++c;
}
- assert(i == node_count);
+ assert(c == n_live_nodes);
/* sort spill candidates */
- qsort(candidates, node_count, sizeof(candidates[0]),
+ qsort(candidates, n_live_nodes, sizeof(candidates[0]),
compare_spill_candidates_desc);
/* spill cheapest ones */
- cand_idx = 0;
- arity = get_irn_arity(node);
- while(spills_needed > 0) {
+ size_t cand_idx = 0;
+ while (spills_needed > 0) {
+ if (cand_idx >= n_live_nodes) {
+ panic("can't spill enough values for node %+F", node);
+ }
+
spill_candidate_t *candidate = &candidates[cand_idx];
ir_node *cand_node = candidate->node;
- int is_use;
++cand_idx;
- if(cand_idx >= node_count) {
- panic("can't spill enough values for node %+F\n", node);
- }
+ if (arch_irn_is(skip_Proj_const(cand_node), dont_spill))
+ continue;
- /* make sure the node is not a use of the instruction */
- is_use = 0;
- for(i = 0; i < arity; ++i) {
+ /* make sure the node is not an argument of the instruction */
+ bool is_use = false;
+ int arity = get_irn_arity(node);
+ for (int i = 0; i < arity; ++i) {
ir_node *in = get_irn_n(node, i);
- if(in == cand_node) {
- is_use = 1;
+ if (in == cand_node) {
+ is_use = true;
break;
}
}
- if(is_use) {
+ if (is_use)
continue;
- }
- spill_node(env, cand_node, nodes);
- --spills_needed;
- if(spill_phis_in != NULL && is_Phi(node) &&
- get_nodes_block(node) == spill_phis_in) {
- DBG((dbg, LEVEL_3, "\tspilled phi\n"));
- be_spill_phi(env->spill_env, node);
- }
+ spill_node(cand_node);
+ ir_nodeset_remove(live_nodes, cand_node);
+ spills_needed -= get_value_width(cand_node);
}
-
- free(candidates);
}
/**
- * similar to be_liveness_transfer.
- * custom liveness transfer function, that doesn't place already spilled values
- * into the liveness set
+ * removes all values from the nodeset that are defined by node
*/
-static
-void liveness_transfer(daemel_env_t *env, ir_node *node, ir_nodeset_t *nodeset)
+static void remove_defs(ir_node *node, ir_nodeset_t *nodeset)
+{
+ /* You must break out of your loop when hitting the first phi function. */
+ assert(!is_Phi(node));
+
+ be_foreach_definition(node, cls, value,
+ ir_nodeset_remove(nodeset, value);
+ );
+}
+
+static void add_uses(ir_node *node, ir_nodeset_t *nodeset)
{
- int i, arity;
- const arch_register_class_t *cls = env->cls;
- const arch_env_t *arch_env = env->arch_env;
- const bitset_t *bitset = env->spilled_nodes;
-
- /* You should better break out of your loop when hitting the first phi
- * function. */
- assert(!is_Phi(node) && "liveness_transfer produces invalid results for phi nodes");
-
- if(arch_irn_consider_in_reg_alloc(arch_env, cls, node)) {
- ir_nodeset_remove(nodeset, node);
- }
-
- 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)
- && !bitset_is_set(bitset, get_irn_idx(op))) {
- ir_nodeset_insert(nodeset, op);
+ int arity = get_irn_arity(node);
+ for (int i = 0; i < arity; ++i) {
+ ir_node *op = get_irn_n(node, i);
+
+ if (arch_irn_consider_in_reg_alloc(cls, op) &&
+ !bitset_is_set(spilled_nodes, get_irn_idx(op))) {
+ ir_nodeset_insert(nodeset, op);
}
- }
+ }
+}
+
+static __attribute__((unused))
+void print_nodeset(ir_nodeset_t *nodeset)
+{
+ foreach_ir_nodeset(nodeset, node, iter) {
+ ir_fprintf(stderr, "%+F ", node);
+ }
+ fprintf(stderr, "\n");
}
/**
* make sure register pressure in a block is always equal or below the number
* of available registers
*/
-static
-void spill_block(ir_node *block, void *data)
+static void spill_block(ir_node *block, void *data)
{
- daemel_env_t *env = data;
- const arch_env_t *arch_env = env->arch_env;
- const arch_register_class_t *cls = env->cls;
- const be_lv_t *lv = env->lv;
- ir_nodeset_t live_nodes;
- ir_nodeset_iterator_t iter;
- ir_node *node;
- bitset_t *spilled_nodes = env->spilled_nodes;
-
+ (void) data;
DBG((dbg, LEVEL_1, "spilling block %+F\n", block));
+ /* construct set of live nodes at end of block */
+ ir_nodeset_t live_nodes;
ir_nodeset_init(&live_nodes);
- be_liveness_end_of_block_ir_nodeset(lv, arch_env, cls, block, &live_nodes);
+ be_liveness_end_of_block(lv, cls, block, &live_nodes);
+ /* remove already spilled nodes from liveset */
foreach_ir_nodeset(&live_nodes, node, iter) {
- DBG((dbg, LEVEL_2, "\t%+F is live-in... ", node));
- if(bitset_is_set(spilled_nodes, get_irn_idx(node))) {
+ DBG((dbg, LEVEL_2, "\t%+F is live-end... ", node));
+ if (bitset_is_set(spilled_nodes, get_irn_idx(node))) {
DBG((dbg, LEVEL_2, "but spilled; removing.\n"));
+ ir_nodeset_remove_iterator(&live_nodes, &iter);
} else {
DBG((dbg, LEVEL_2, "keeping.\n"));
}
}
+ /* walk schedule backwards and spill until register pressure is fine at
+ * each node */
sched_foreach_reverse(block, node) {
- if(is_Phi(node))
+ if (is_Phi(node))
break;
- if(is_Proj(node) || be_is_Keep(node)) {
- liveness_transfer(env, node, &live_nodes);
- continue;
- }
+ remove_defs(node, &live_nodes);
+ do_spilling(&live_nodes, node);
+ add_uses(node, &live_nodes);
+ }
- do_spilling(env, &live_nodes, node, NULL);
+ /* until now only the values of some phis have been spilled the phis itself
+ * are still there and occupy registers, so we need to count them and might
+ * have to spill some of them. */
+ int n_phi_values_spilled = 0;
+ sched_foreach(block, node) {
+ if (!is_Phi(node))
+ break;
- liveness_transfer(env, node, &live_nodes);
+ if (bitset_is_set(spilled_nodes, get_irn_idx(node))) {
+ n_phi_values_spilled += get_value_width(node);
+ }
+ }
+
+ int live_nodes_pressure = 0;
+ foreach_ir_nodeset(&live_nodes, node, iter) {
+ live_nodes_pressure += get_value_width(node);
}
- do_spilling(env, &live_nodes, node, block);
+ /* calculate how many of the phis need to be spilled */
+ int regpressure = live_nodes_pressure + n_phi_values_spilled;
+ int phi_spills_needed = regpressure - n_regs;
+ DBG((dbg, LEVEL_3, "Regpressure before phis: %d phispills: %d\n",
+ regpressure, phi_spills_needed));
+
+ /* spill as many phis as needed */
+ /* TODO: we should really estimate costs of the phi spill as well...
+ * and preferably spill phis with lower costs... */
+ sched_foreach(block, node) {
+ if (!is_Phi(node))
+ break;
+ if (phi_spills_needed <= 0)
+ break;
+
+ if (!bitset_is_set(spilled_nodes, get_irn_idx(node)))
+ continue;
+
+ be_spill_phi(spill_env, node);
+ phi_spills_needed -= get_value_width(node);
+ }
+ assert(phi_spills_needed <= 0);
ir_nodeset_destroy(&live_nodes);
}
-void be_spill_daemel(be_irg_t *birg, const arch_register_class_t *cls)
+static void be_spill_daemel(ir_graph *irg, const arch_register_class_t *new_cls)
{
- daemel_env_t env;
- ir_graph *irg = be_get_birg_irg(birg);
- int n_regs = cls->n_regs - be_put_ignore_regs(birg, cls, NULL);
-
- if(n_regs == 0)
+ n_regs = be_get_n_allocatable_regs(irg, new_cls);
+ if (n_regs == 0)
return;
- be_invalidate_liveness(birg);
- be_assure_liveness(birg);
+ be_assure_live_sets(irg);
- env.spill_env = be_new_spill_env(birg);
- env.n_regs = n_regs;
- env.arch_env = be_get_birg_arch_env(birg);
- env.cls = cls;
- env.lv = be_get_birg_liveness(birg);
- env.spilled_nodes = bitset_malloc(get_irg_last_idx(irg));
+ spill_env = be_new_spill_env(irg);
+ cls = new_cls;
+ lv = be_get_irg_liveness(irg);
+ spilled_nodes = bitset_malloc(get_irg_last_idx(irg));
- irg_block_walk_graph(irg, spill_block, NULL, &env);
+ DBG((dbg, LEVEL_1, "*** RegClass %s\n", cls->name));
- bitset_free(env.spilled_nodes);
+ irg_block_walk_graph(irg, spill_block, NULL, NULL);
- be_insert_spills_reloads(env.spill_env);
+ bitset_free(spilled_nodes);
- be_delete_spill_env(env.spill_env);
+ be_insert_spills_reloads(spill_env);
+ be_delete_spill_env(spill_env);
}
+BE_REGISTER_MODULE_CONSTRUCTOR(be_init_daemelspill)
void be_init_daemelspill(void)
{
static be_spiller_t daemel_spiller = {
};
be_register_spiller("daemel", &daemel_spiller);
- FIRM_DBG_REGISTER(dbg, "ir.be.spilldaemel");
+ FIRM_DBG_REGISTER(dbg, "firm.be.spilldaemel");
}
-
-BE_REGISTER_MODULE_CONSTRUCTOR(be_init_doedelspill);
projects / libfirm / blobdiff