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-rw-r--r--mesalib/src/mesa/program/register_allocate.c972
1 files changed, 517 insertions, 455 deletions
diff --git a/mesalib/src/mesa/program/register_allocate.c b/mesalib/src/mesa/program/register_allocate.c
index 95a9bde40..e78db24a4 100644
--- a/mesalib/src/mesa/program/register_allocate.c
+++ b/mesalib/src/mesa/program/register_allocate.c
@@ -1,455 +1,517 @@
-/*
- * Copyright © 2010 Intel Corporation
- *
- * Permission is hereby granted, free of charge, to any person obtaining a
- * copy of this software and associated documentation files (the "Software"),
- * to deal in the Software without restriction, including without limitation
- * the rights to use, copy, modify, merge, publish, distribute, sublicense,
- * and/or sell copies of the Software, and to permit persons to whom the
- * Software is furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice (including the next
- * paragraph) shall be included in all copies or substantial portions of the
- * Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
- * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
- * IN THE SOFTWARE.
- *
- * Authors:
- * Eric Anholt <eric@anholt.net>
- *
- */
-
-/** @file register_allocate.c
- *
- * Graph-coloring register allocator.
- */
-
-#include <ralloc.h>
-
-#include "main/imports.h"
-#include "main/macros.h"
-#include "main/mtypes.h"
-#include "register_allocate.h"
-
-struct ra_reg {
- GLboolean *conflicts;
- unsigned int *conflict_list;
- unsigned int conflict_list_size;
- unsigned int num_conflicts;
-};
-
-struct ra_regs {
- struct ra_reg *regs;
- unsigned int count;
-
- struct ra_class **classes;
- unsigned int class_count;
-};
-
-struct ra_class {
- GLboolean *regs;
-
- /**
- * p_B in Runeson/Nyström paper.
- *
- * This is "how many regs are in the set."
- */
- unsigned int p;
-
- /**
- * q_B,C in Runeson/Nyström paper.
- */
- unsigned int *q;
-};
-
-struct ra_node {
- GLboolean *adjacency;
- unsigned int *adjacency_list;
- unsigned int class;
- unsigned int adjacency_count;
- unsigned int reg;
- GLboolean in_stack;
- float spill_cost;
-};
-
-struct ra_graph {
- struct ra_regs *regs;
- /**
- * the variables that need register allocation.
- */
- struct ra_node *nodes;
- unsigned int count; /**< count of nodes. */
-
- unsigned int *stack;
- unsigned int stack_count;
-};
-
-struct ra_regs *
-ra_alloc_reg_set(unsigned int count)
-{
- unsigned int i;
- struct ra_regs *regs;
-
- regs = rzalloc(NULL, struct ra_regs);
- regs->count = count;
- regs->regs = rzalloc_array(regs, struct ra_reg, count);
-
- for (i = 0; i < count; i++) {
- regs->regs[i].conflicts = rzalloc_array(regs->regs, GLboolean, count);
- regs->regs[i].conflicts[i] = GL_TRUE;
-
- regs->regs[i].conflict_list = ralloc_array(regs->regs, unsigned int, 4);
- regs->regs[i].conflict_list_size = 4;
- regs->regs[i].conflict_list[0] = i;
- regs->regs[i].num_conflicts = 1;
- }
-
- return regs;
-}
-
-static void
-ra_add_conflict_list(struct ra_regs *regs, unsigned int r1, unsigned int r2)
-{
- struct ra_reg *reg1 = &regs->regs[r1];
-
- if (reg1->conflict_list_size == reg1->num_conflicts) {
- reg1->conflict_list_size *= 2;
- reg1->conflict_list = reralloc(regs->regs, reg1->conflict_list,
- unsigned int, reg1->conflict_list_size);
- }
- reg1->conflict_list[reg1->num_conflicts++] = r2;
- reg1->conflicts[r2] = GL_TRUE;
-}
-
-void
-ra_add_reg_conflict(struct ra_regs *regs, unsigned int r1, unsigned int r2)
-{
- if (!regs->regs[r1].conflicts[r2]) {
- ra_add_conflict_list(regs, r1, r2);
- ra_add_conflict_list(regs, r2, r1);
- }
-}
-
-unsigned int
-ra_alloc_reg_class(struct ra_regs *regs)
-{
- struct ra_class *class;
-
- regs->classes = reralloc(regs->regs, regs->classes, struct ra_class *,
- regs->class_count + 1);
-
- class = rzalloc(regs, struct ra_class);
- regs->classes[regs->class_count] = class;
-
- class->regs = rzalloc_array(class, GLboolean, regs->count);
-
- return regs->class_count++;
-}
-
-void
-ra_class_add_reg(struct ra_regs *regs, unsigned int c, unsigned int r)
-{
- struct ra_class *class = regs->classes[c];
-
- class->regs[r] = GL_TRUE;
- class->p++;
-}
-
-/**
- * Must be called after all conflicts and register classes have been
- * set up and before the register set is used for allocation.
- */
-void
-ra_set_finalize(struct ra_regs *regs)
-{
- unsigned int b, c;
-
- for (b = 0; b < regs->class_count; b++) {
- regs->classes[b]->q = ralloc_array(regs, unsigned int, regs->class_count);
- }
-
- /* Compute, for each class B and C, how many regs of B an
- * allocation to C could conflict with.
- */
- for (b = 0; b < regs->class_count; b++) {
- for (c = 0; c < regs->class_count; c++) {
- unsigned int rc;
- int max_conflicts = 0;
-
- for (rc = 0; rc < regs->count; rc++) {
- int conflicts = 0;
- int i;
-
- if (!regs->classes[c]->regs[rc])
- continue;
-
- for (i = 0; i < regs->regs[rc].num_conflicts; i++) {
- unsigned int rb = regs->regs[rc].conflict_list[i];
- if (regs->classes[b]->regs[rb])
- conflicts++;
- }
- max_conflicts = MAX2(max_conflicts, conflicts);
- }
- regs->classes[b]->q[c] = max_conflicts;
- }
- }
-}
-
-static void
-ra_add_node_adjacency(struct ra_graph *g, unsigned int n1, unsigned int n2)
-{
- g->nodes[n1].adjacency[n2] = GL_TRUE;
- g->nodes[n1].adjacency_list[g->nodes[n1].adjacency_count] = n2;
- g->nodes[n1].adjacency_count++;
-}
-
-struct ra_graph *
-ra_alloc_interference_graph(struct ra_regs *regs, unsigned int count)
-{
- struct ra_graph *g;
- unsigned int i;
-
- g = rzalloc(regs, struct ra_graph);
- g->regs = regs;
- g->nodes = rzalloc_array(g, struct ra_node, count);
- g->count = count;
-
- g->stack = rzalloc_array(g, unsigned int, count);
-
- for (i = 0; i < count; i++) {
- g->nodes[i].adjacency = rzalloc_array(g, GLboolean, count);
- g->nodes[i].adjacency_list = ralloc_array(g, unsigned int, count);
- g->nodes[i].adjacency_count = 0;
- ra_add_node_adjacency(g, i, i);
- g->nodes[i].reg = ~0;
- }
-
- return g;
-}
-
-void
-ra_set_node_class(struct ra_graph *g,
- unsigned int n, unsigned int class)
-{
- g->nodes[n].class = class;
-}
-
-void
-ra_add_node_interference(struct ra_graph *g,
- unsigned int n1, unsigned int n2)
-{
- if (!g->nodes[n1].adjacency[n2]) {
- ra_add_node_adjacency(g, n1, n2);
- ra_add_node_adjacency(g, n2, n1);
- }
-}
-
-static GLboolean pq_test(struct ra_graph *g, unsigned int n)
-{
- unsigned int j;
- unsigned int q = 0;
- int n_class = g->nodes[n].class;
-
- for (j = 0; j < g->nodes[n].adjacency_count; j++) {
- unsigned int n2 = g->nodes[n].adjacency_list[j];
- unsigned int n2_class = g->nodes[n2].class;
-
- if (n != n2 && !g->nodes[n2].in_stack) {
- q += g->regs->classes[n_class]->q[n2_class];
- }
- }
-
- return q < g->regs->classes[n_class]->p;
-}
-
-/**
- * Simplifies the interference graph by pushing all
- * trivially-colorable nodes into a stack of nodes to be colored,
- * removing them from the graph, and rinsing and repeating.
- *
- * Returns GL_TRUE if all nodes were removed from the graph. GL_FALSE
- * means that either spilling will be required, or optimistic coloring
- * should be applied.
- */
-GLboolean
-ra_simplify(struct ra_graph *g)
-{
- GLboolean progress = GL_TRUE;
- int i;
-
- while (progress) {
- progress = GL_FALSE;
-
- for (i = g->count - 1; i >= 0; i--) {
- if (g->nodes[i].in_stack)
- continue;
-
- if (pq_test(g, i)) {
- g->stack[g->stack_count] = i;
- g->stack_count++;
- g->nodes[i].in_stack = GL_TRUE;
- progress = GL_TRUE;
- }
- }
- }
-
- for (i = 0; i < g->count; i++) {
- if (!g->nodes[i].in_stack)
- return GL_FALSE;
- }
-
- return GL_TRUE;
-}
-
-/**
- * Pops nodes from the stack back into the graph, coloring them with
- * registers as they go.
- *
- * If all nodes were trivially colorable, then this must succeed. If
- * not (optimistic coloring), then it may return GL_FALSE;
- */
-GLboolean
-ra_select(struct ra_graph *g)
-{
- int i;
-
- while (g->stack_count != 0) {
- unsigned int r;
- int n = g->stack[g->stack_count - 1];
- struct ra_class *c = g->regs->classes[g->nodes[n].class];
-
- /* Find the lowest-numbered reg which is not used by a member
- * of the graph adjacent to us.
- */
- for (r = 0; r < g->regs->count; r++) {
- if (!c->regs[r])
- continue;
-
- /* Check if any of our neighbors conflict with this register choice. */
- for (i = 0; i < g->nodes[n].adjacency_count; i++) {
- unsigned int n2 = g->nodes[n].adjacency_list[i];
-
- if (!g->nodes[n2].in_stack &&
- g->regs->regs[r].conflicts[g->nodes[n2].reg]) {
- break;
- }
- }
- if (i == g->nodes[n].adjacency_count)
- break;
- }
- if (r == g->regs->count)
- return GL_FALSE;
-
- g->nodes[n].reg = r;
- g->nodes[n].in_stack = GL_FALSE;
- g->stack_count--;
- }
-
- return GL_TRUE;
-}
-
-/**
- * Optimistic register coloring: Just push the remaining nodes
- * on the stack. They'll be colored first in ra_select(), and
- * if they succeed then the locally-colorable nodes are still
- * locally-colorable and the rest of the register allocation
- * will succeed.
- */
-void
-ra_optimistic_color(struct ra_graph *g)
-{
- unsigned int i;
-
- for (i = 0; i < g->count; i++) {
- if (g->nodes[i].in_stack)
- continue;
-
- g->stack[g->stack_count] = i;
- g->stack_count++;
- g->nodes[i].in_stack = GL_TRUE;
- }
-}
-
-GLboolean
-ra_allocate_no_spills(struct ra_graph *g)
-{
- if (!ra_simplify(g)) {
- ra_optimistic_color(g);
- }
- return ra_select(g);
-}
-
-unsigned int
-ra_get_node_reg(struct ra_graph *g, unsigned int n)
-{
- return g->nodes[n].reg;
-}
-
-static float
-ra_get_spill_benefit(struct ra_graph *g, unsigned int n)
-{
- int j;
- float benefit = 0;
- int n_class = g->nodes[n].class;
-
- /* Define the benefit of eliminating an interference between n, n2
- * through spilling as q(C, B) / p(C). This is similar to the
- * "count number of edges" approach of traditional graph coloring,
- * but takes classes into account.
- */
- for (j = 0; j < g->nodes[n].adjacency_count; j++) {
- unsigned int n2 = g->nodes[n].adjacency_list[j];
- if (n != n2) {
- unsigned int n2_class = g->nodes[n2].class;
- benefit += ((float)g->regs->classes[n_class]->q[n2_class] /
- g->regs->classes[n_class]->p);
- }
- }
-
- return benefit;
-}
-
-/**
- * Returns a node number to be spilled according to the cost/benefit using
- * the pq test, or -1 if there are no spillable nodes.
- */
-int
-ra_get_best_spill_node(struct ra_graph *g)
-{
- unsigned int best_node = -1;
- unsigned int best_benefit = 0.0;
- unsigned int n;
-
- for (n = 0; n < g->count; n++) {
- float cost = g->nodes[n].spill_cost;
- float benefit;
-
- if (cost <= 0.0)
- continue;
-
- benefit = ra_get_spill_benefit(g, n);
-
- if (benefit / cost > best_benefit) {
- best_benefit = benefit / cost;
- best_node = n;
- }
- }
-
- return best_node;
-}
-
-/**
- * Only nodes with a spill cost set (cost != 0.0) will be considered
- * for register spilling.
- */
-void
-ra_set_node_spill_cost(struct ra_graph *g, unsigned int n, float cost)
-{
- g->nodes[n].spill_cost = cost;
-}
+/*
+ * Copyright © 2010 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ * Authors:
+ * Eric Anholt <eric@anholt.net>
+ *
+ */
+
+/** @file register_allocate.c
+ *
+ * Graph-coloring register allocator.
+ *
+ * The basic idea of graph coloring is to make a node in a graph for
+ * every thing that needs a register (color) number assigned, and make
+ * edges in the graph between nodes that interfere (can't be allocated
+ * to the same register at the same time).
+ *
+ * During the "simplify" process, any any node with fewer edges than
+ * there are registers means that that edge can get assigned a
+ * register regardless of what its neighbors choose, so that node is
+ * pushed on a stack and removed (with its edges) from the graph.
+ * That likely causes other nodes to become trivially colorable as well.
+ *
+ * Then during the "select" process, nodes are popped off of that
+ * stack, their edges restored, and assigned a color different from
+ * their neighbors. Because they were pushed on the stack only when
+ * they were trivially colorable, any color chosen won't interfere
+ * with the registers to be popped later.
+ *
+ * The downside to most graph coloring is that real hardware often has
+ * limitations, like registers that need to be allocated to a node in
+ * pairs, or aligned on some boundary. This implementation follows
+ * the paper "Retargetable Graph-Coloring Register Allocation for
+ * Irregular Architectures" by Johan Runeson and Sven-Olof Nyström.
+ *
+ * In this system, there are register classes each containing various
+ * registers, and registers may interfere with other registers. For
+ * example, one might have a class of base registers, and a class of
+ * aligned register pairs that would each interfere with their pair of
+ * the base registers. Each node has a register class it needs to be
+ * assigned to. Define p(B) to be the size of register class B, and
+ * q(B,C) to be the number of registers in B that the worst choice
+ * register in C could conflict with. Then, this system replaces the
+ * basic graph coloring test of "fewer edges from this node than there
+ * are registers" with "For this node of class B, the sum of q(B,C)
+ * for each neighbor node of class C is less than pB".
+ *
+ * A nice feature of the pq test is that q(B,C) can be computed once
+ * up front and stored in a 2-dimensional array, so that the cost of
+ * coloring a node is constant with the number of registers. We do
+ * this during ra_set_finalize().
+ */
+
+#include <ralloc.h>
+
+#include "main/imports.h"
+#include "main/macros.h"
+#include "main/mtypes.h"
+#include "register_allocate.h"
+
+struct ra_reg {
+ GLboolean *conflicts;
+ unsigned int *conflict_list;
+ unsigned int conflict_list_size;
+ unsigned int num_conflicts;
+};
+
+struct ra_regs {
+ struct ra_reg *regs;
+ unsigned int count;
+
+ struct ra_class **classes;
+ unsigned int class_count;
+};
+
+struct ra_class {
+ GLboolean *regs;
+
+ /**
+ * p(B) in Runeson/Nyström paper.
+ *
+ * This is "how many regs are in the set."
+ */
+ unsigned int p;
+
+ /**
+ * q(B,C) (indexed by C, B is this register class) in
+ * Runeson/Nyström paper. This is "how many registers of B could
+ * the worst choice register from C conflict with".
+ */
+ unsigned int *q;
+};
+
+struct ra_node {
+ /** @{
+ *
+ * List of which nodes this node interferes with. This should be
+ * symmetric with the other node.
+ */
+ GLboolean *adjacency;
+ unsigned int *adjacency_list;
+ unsigned int adjacency_count;
+ /** @} */
+
+ unsigned int class;
+
+ /* Register, if assigned, or ~0. */
+ unsigned int reg;
+
+ /**
+ * Set when the node is in the trivially colorable stack. When
+ * set, the adjacency to this node is ignored, to implement the
+ * "remove the edge from the graph" in simplification without
+ * having to actually modify the adjacency_list.
+ */
+ GLboolean in_stack;
+
+ /* For an implementation that needs register spilling, this is the
+ * approximate cost of spilling this node.
+ */
+ float spill_cost;
+};
+
+struct ra_graph {
+ struct ra_regs *regs;
+ /**
+ * the variables that need register allocation.
+ */
+ struct ra_node *nodes;
+ unsigned int count; /**< count of nodes. */
+
+ unsigned int *stack;
+ unsigned int stack_count;
+};
+
+struct ra_regs *
+ra_alloc_reg_set(unsigned int count)
+{
+ unsigned int i;
+ struct ra_regs *regs;
+
+ regs = rzalloc(NULL, struct ra_regs);
+ regs->count = count;
+ regs->regs = rzalloc_array(regs, struct ra_reg, count);
+
+ for (i = 0; i < count; i++) {
+ regs->regs[i].conflicts = rzalloc_array(regs->regs, GLboolean, count);
+ regs->regs[i].conflicts[i] = GL_TRUE;
+
+ regs->regs[i].conflict_list = ralloc_array(regs->regs, unsigned int, 4);
+ regs->regs[i].conflict_list_size = 4;
+ regs->regs[i].conflict_list[0] = i;
+ regs->regs[i].num_conflicts = 1;
+ }
+
+ return regs;
+}
+
+static void
+ra_add_conflict_list(struct ra_regs *regs, unsigned int r1, unsigned int r2)
+{
+ struct ra_reg *reg1 = &regs->regs[r1];
+
+ if (reg1->conflict_list_size == reg1->num_conflicts) {
+ reg1->conflict_list_size *= 2;
+ reg1->conflict_list = reralloc(regs->regs, reg1->conflict_list,
+ unsigned int, reg1->conflict_list_size);
+ }
+ reg1->conflict_list[reg1->num_conflicts++] = r2;
+ reg1->conflicts[r2] = GL_TRUE;
+}
+
+void
+ra_add_reg_conflict(struct ra_regs *regs, unsigned int r1, unsigned int r2)
+{
+ if (!regs->regs[r1].conflicts[r2]) {
+ ra_add_conflict_list(regs, r1, r2);
+ ra_add_conflict_list(regs, r2, r1);
+ }
+}
+
+unsigned int
+ra_alloc_reg_class(struct ra_regs *regs)
+{
+ struct ra_class *class;
+
+ regs->classes = reralloc(regs->regs, regs->classes, struct ra_class *,
+ regs->class_count + 1);
+
+ class = rzalloc(regs, struct ra_class);
+ regs->classes[regs->class_count] = class;
+
+ class->regs = rzalloc_array(class, GLboolean, regs->count);
+
+ return regs->class_count++;
+}
+
+void
+ra_class_add_reg(struct ra_regs *regs, unsigned int c, unsigned int r)
+{
+ struct ra_class *class = regs->classes[c];
+
+ class->regs[r] = GL_TRUE;
+ class->p++;
+}
+
+/**
+ * Must be called after all conflicts and register classes have been
+ * set up and before the register set is used for allocation.
+ */
+void
+ra_set_finalize(struct ra_regs *regs)
+{
+ unsigned int b, c;
+
+ for (b = 0; b < regs->class_count; b++) {
+ regs->classes[b]->q = ralloc_array(regs, unsigned int, regs->class_count);
+ }
+
+ /* Compute, for each class B and C, how many regs of B an
+ * allocation to C could conflict with.
+ */
+ for (b = 0; b < regs->class_count; b++) {
+ for (c = 0; c < regs->class_count; c++) {
+ unsigned int rc;
+ int max_conflicts = 0;
+
+ for (rc = 0; rc < regs->count; rc++) {
+ int conflicts = 0;
+ int i;
+
+ if (!regs->classes[c]->regs[rc])
+ continue;
+
+ for (i = 0; i < regs->regs[rc].num_conflicts; i++) {
+ unsigned int rb = regs->regs[rc].conflict_list[i];
+ if (regs->classes[b]->regs[rb])
+ conflicts++;
+ }
+ max_conflicts = MAX2(max_conflicts, conflicts);
+ }
+ regs->classes[b]->q[c] = max_conflicts;
+ }
+ }
+}
+
+static void
+ra_add_node_adjacency(struct ra_graph *g, unsigned int n1, unsigned int n2)
+{
+ g->nodes[n1].adjacency[n2] = GL_TRUE;
+ g->nodes[n1].adjacency_list[g->nodes[n1].adjacency_count] = n2;
+ g->nodes[n1].adjacency_count++;
+}
+
+struct ra_graph *
+ra_alloc_interference_graph(struct ra_regs *regs, unsigned int count)
+{
+ struct ra_graph *g;
+ unsigned int i;
+
+ g = rzalloc(regs, struct ra_graph);
+ g->regs = regs;
+ g->nodes = rzalloc_array(g, struct ra_node, count);
+ g->count = count;
+
+ g->stack = rzalloc_array(g, unsigned int, count);
+
+ for (i = 0; i < count; i++) {
+ g->nodes[i].adjacency = rzalloc_array(g, GLboolean, count);
+ g->nodes[i].adjacency_list = ralloc_array(g, unsigned int, count);
+ g->nodes[i].adjacency_count = 0;
+ ra_add_node_adjacency(g, i, i);
+ g->nodes[i].reg = ~0;
+ }
+
+ return g;
+}
+
+void
+ra_set_node_class(struct ra_graph *g,
+ unsigned int n, unsigned int class)
+{
+ g->nodes[n].class = class;
+}
+
+void
+ra_add_node_interference(struct ra_graph *g,
+ unsigned int n1, unsigned int n2)
+{
+ if (!g->nodes[n1].adjacency[n2]) {
+ ra_add_node_adjacency(g, n1, n2);
+ ra_add_node_adjacency(g, n2, n1);
+ }
+}
+
+static GLboolean pq_test(struct ra_graph *g, unsigned int n)
+{
+ unsigned int j;
+ unsigned int q = 0;
+ int n_class = g->nodes[n].class;
+
+ for (j = 0; j < g->nodes[n].adjacency_count; j++) {
+ unsigned int n2 = g->nodes[n].adjacency_list[j];
+ unsigned int n2_class = g->nodes[n2].class;
+
+ if (n != n2 && !g->nodes[n2].in_stack) {
+ q += g->regs->classes[n_class]->q[n2_class];
+ }
+ }
+
+ return q < g->regs->classes[n_class]->p;
+}
+
+/**
+ * Simplifies the interference graph by pushing all
+ * trivially-colorable nodes into a stack of nodes to be colored,
+ * removing them from the graph, and rinsing and repeating.
+ *
+ * Returns GL_TRUE if all nodes were removed from the graph. GL_FALSE
+ * means that either spilling will be required, or optimistic coloring
+ * should be applied.
+ */
+GLboolean
+ra_simplify(struct ra_graph *g)
+{
+ GLboolean progress = GL_TRUE;
+ int i;
+
+ while (progress) {
+ progress = GL_FALSE;
+
+ for (i = g->count - 1; i >= 0; i--) {
+ if (g->nodes[i].in_stack)
+ continue;
+
+ if (pq_test(g, i)) {
+ g->stack[g->stack_count] = i;
+ g->stack_count++;
+ g->nodes[i].in_stack = GL_TRUE;
+ progress = GL_TRUE;
+ }
+ }
+ }
+
+ for (i = 0; i < g->count; i++) {
+ if (!g->nodes[i].in_stack)
+ return GL_FALSE;
+ }
+
+ return GL_TRUE;
+}
+
+/**
+ * Pops nodes from the stack back into the graph, coloring them with
+ * registers as they go.
+ *
+ * If all nodes were trivially colorable, then this must succeed. If
+ * not (optimistic coloring), then it may return GL_FALSE;
+ */
+GLboolean
+ra_select(struct ra_graph *g)
+{
+ int i;
+
+ while (g->stack_count != 0) {
+ unsigned int r;
+ int n = g->stack[g->stack_count - 1];
+ struct ra_class *c = g->regs->classes[g->nodes[n].class];
+
+ /* Find the lowest-numbered reg which is not used by a member
+ * of the graph adjacent to us.
+ */
+ for (r = 0; r < g->regs->count; r++) {
+ if (!c->regs[r])
+ continue;
+
+ /* Check if any of our neighbors conflict with this register choice. */
+ for (i = 0; i < g->nodes[n].adjacency_count; i++) {
+ unsigned int n2 = g->nodes[n].adjacency_list[i];
+
+ if (!g->nodes[n2].in_stack &&
+ g->regs->regs[r].conflicts[g->nodes[n2].reg]) {
+ break;
+ }
+ }
+ if (i == g->nodes[n].adjacency_count)
+ break;
+ }
+ if (r == g->regs->count)
+ return GL_FALSE;
+
+ g->nodes[n].reg = r;
+ g->nodes[n].in_stack = GL_FALSE;
+ g->stack_count--;
+ }
+
+ return GL_TRUE;
+}
+
+/**
+ * Optimistic register coloring: Just push the remaining nodes
+ * on the stack. They'll be colored first in ra_select(), and
+ * if they succeed then the locally-colorable nodes are still
+ * locally-colorable and the rest of the register allocation
+ * will succeed.
+ */
+void
+ra_optimistic_color(struct ra_graph *g)
+{
+ unsigned int i;
+
+ for (i = 0; i < g->count; i++) {
+ if (g->nodes[i].in_stack)
+ continue;
+
+ g->stack[g->stack_count] = i;
+ g->stack_count++;
+ g->nodes[i].in_stack = GL_TRUE;
+ }
+}
+
+GLboolean
+ra_allocate_no_spills(struct ra_graph *g)
+{
+ if (!ra_simplify(g)) {
+ ra_optimistic_color(g);
+ }
+ return ra_select(g);
+}
+
+unsigned int
+ra_get_node_reg(struct ra_graph *g, unsigned int n)
+{
+ return g->nodes[n].reg;
+}
+
+static float
+ra_get_spill_benefit(struct ra_graph *g, unsigned int n)
+{
+ int j;
+ float benefit = 0;
+ int n_class = g->nodes[n].class;
+
+ /* Define the benefit of eliminating an interference between n, n2
+ * through spilling as q(C, B) / p(C). This is similar to the
+ * "count number of edges" approach of traditional graph coloring,
+ * but takes classes into account.
+ */
+ for (j = 0; j < g->nodes[n].adjacency_count; j++) {
+ unsigned int n2 = g->nodes[n].adjacency_list[j];
+ if (n != n2) {
+ unsigned int n2_class = g->nodes[n2].class;
+ benefit += ((float)g->regs->classes[n_class]->q[n2_class] /
+ g->regs->classes[n_class]->p);
+ }
+ }
+
+ return benefit;
+}
+
+/**
+ * Returns a node number to be spilled according to the cost/benefit using
+ * the pq test, or -1 if there are no spillable nodes.
+ */
+int
+ra_get_best_spill_node(struct ra_graph *g)
+{
+ unsigned int best_node = -1;
+ unsigned int best_benefit = 0.0;
+ unsigned int n;
+
+ for (n = 0; n < g->count; n++) {
+ float cost = g->nodes[n].spill_cost;
+ float benefit;
+
+ if (cost <= 0.0)
+ continue;
+
+ benefit = ra_get_spill_benefit(g, n);
+
+ if (benefit / cost > best_benefit) {
+ best_benefit = benefit / cost;
+ best_node = n;
+ }
+ }
+
+ return best_node;
+}
+
+/**
+ * Only nodes with a spill cost set (cost != 0.0) will be considered
+ * for register spilling.
+ */
+void
+ra_set_node_spill_cost(struct ra_graph *g, unsigned int n, float cost)
+{
+ g->nodes[n].spill_cost = cost;
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-02 17:04:18 +0000