#include "ralloc.h"
#include "main/imports.h"
#include "main/macros.h"
-#include "main/mtypes.h"
#include "util/bitset.h"
#include "register_allocate.h"
unsigned int class;
+ /* Client-assigned register, if assigned, or NO_REG. */
+ unsigned int forced_reg;
+
/* Register, if assigned, or NO_REG. */
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.
- */
- bool in_stack;
-
/**
* The q total, as defined in the Runeson/Nyström paper, for all the
* interfering nodes not in the stack.
* approximate cost of spilling this node.
*/
float spill_cost;
+
+ /* Temporary data for the algorithm to scratch around in */
+ struct {
+ /**
+ * Temporary version of q_total which we decrement as things are placed
+ * into the stack.
+ */
+ unsigned int q_total;
+ } tmp;
};
struct ra_graph {
struct ra_node *nodes;
unsigned int count; /**< count of nodes. */
- unsigned int *stack;
- unsigned int stack_count;
+ unsigned int alloc; /**< count of nodes allocated. */
- /**
- * Tracks the start of the set of optimistically-colored registers in the
- * stack.
- */
- unsigned int stack_optimistic_start;
+ ra_select_reg_callback select_reg_callback;
+ void *select_reg_callback_data;
+
+ /* Temporary data for the algorithm to scratch around in */
+ struct {
+ unsigned int *stack;
+ unsigned int stack_count;
+
+ /** Bit-set indicating, for each register, if it's in the stack */
+ BITSET_WORD *in_stack;
+
+ /** Bit-set indicating, for each register, if it pre-assigned */
+ BITSET_WORD *reg_assigned;
+
+ /** Bit-set indicating, for each register, the value of the pq test */
+ BITSET_WORD *pq_test;
+
+ /** For each BITSET_WORD, the minimum q value or ~0 if unknown */
+ unsigned int *min_q_total;
+
+ /*
+ * * For each BITSET_WORD, the node with the minimum q_total if
+ * min_q_total[i] != ~0.
+ */
+ unsigned int *min_q_node;
+
+ /**
+ * Tracks the start of the set of optimistically-colored registers in the
+ * stack.
+ */
+ unsigned int stack_optimistic_start;
+ } tmp;
};
/**
}
}
+/**
+ * Set up conflicts between base_reg and it's two half registers reg0 and
+ * reg1, but take care to not add conflicts between reg0 and reg1.
+ *
+ * This is useful for architectures where full size registers are aliased by
+ * two half size registers (eg 32 bit float and 16 bit float registers).
+ */
+void
+ra_add_transitive_reg_pair_conflict(struct ra_regs *regs,
+ unsigned int base_reg, unsigned int reg0, unsigned int reg1)
+{
+ unsigned int i;
+
+ ra_add_reg_conflict(regs, reg0, base_reg);
+ ra_add_reg_conflict(regs, reg1, base_reg);
+
+ for (i = 0; i < regs->regs[base_reg].num_conflicts; i++) {
+ unsigned int conflict = regs->regs[base_reg].conflict_list[i];
+ if (conflict != reg1)
+ ra_add_reg_conflict(regs, reg0, regs->regs[base_reg].conflict_list[i]);
+ if (conflict != reg0)
+ ra_add_reg_conflict(regs, reg1, regs->regs[base_reg].conflict_list[i]);
+ }
+}
+
/**
* Makes every conflict on the given register transitive. In other words,
* every register that conflicts with r will now conflict with every other
ra_make_reg_conflicts_transitive(struct ra_regs *regs, unsigned int r)
{
struct ra_reg *reg = ®s->regs[r];
- BITSET_WORD tmp;
int c;
- BITSET_FOREACH_SET(c, tmp, reg->conflicts, regs->count) {
+ BITSET_FOREACH_SET(c, reg->conflicts, regs->count) {
struct ra_reg *other = ®s->regs[c];
unsigned i;
for (i = 0; i < BITSET_WORDS(regs->count); i++)
{
BITSET_SET(g->nodes[n1].adjacency, n2);
- if (n1 != n2) {
- int n1_class = g->nodes[n1].class;
- int n2_class = g->nodes[n2].class;
- g->nodes[n1].q_total += g->regs->classes[n1_class]->q[n2_class];
- }
+ assert(n1 != n2);
+
+ int n1_class = g->nodes[n1].class;
+ int n2_class = g->nodes[n2].class;
+ g->nodes[n1].q_total += g->regs->classes[n1_class]->q[n2_class];
if (g->nodes[n1].adjacency_count >=
g->nodes[n1].adjacency_list_size) {
g->nodes[n1].adjacency_count++;
}
-struct ra_graph *
-ra_alloc_interference_graph(struct ra_regs *regs, unsigned int count)
+static void
+ra_node_remove_adjacency(struct ra_graph *g, unsigned int n1, unsigned int n2)
{
- struct ra_graph *g;
+ BITSET_CLEAR(g->nodes[n1].adjacency, n2);
+
+ assert(n1 != n2);
+
+ int n1_class = g->nodes[n1].class;
+ int n2_class = g->nodes[n2].class;
+ g->nodes[n1].q_total -= g->regs->classes[n1_class]->q[n2_class];
+
unsigned int i;
+ for (i = 0; i < g->nodes[n1].adjacency_count; i++) {
+ if (g->nodes[n1].adjacency_list[i] == n2) {
+ memmove(&g->nodes[n1].adjacency_list[i],
+ &g->nodes[n1].adjacency_list[i + 1],
+ (g->nodes[n1].adjacency_count - i - 1) *
+ sizeof(g->nodes[n1].adjacency_list[0]));
+ break;
+ }
+ }
+ assert(i < g->nodes[n1].adjacency_count);
+ g->nodes[n1].adjacency_count--;
+}
- g = rzalloc(NULL, struct ra_graph);
- g->regs = regs;
- g->nodes = rzalloc_array(g, struct ra_node, count);
- g->count = count;
+static void
+ra_realloc_interference_graph(struct ra_graph *g, unsigned int alloc)
+{
+ if (alloc <= g->alloc)
+ return;
- g->stack = rzalloc_array(g, unsigned int, count);
+ /* If we always have a whole number of BITSET_WORDs, it makes it much
+ * easier to memset the top of the growing bitsets.
+ */
+ assert(g->alloc % BITSET_WORDBITS == 0);
+ alloc = ALIGN(alloc, BITSET_WORDBITS);
+
+ g->nodes = reralloc(g, g->nodes, struct ra_node, alloc);
+
+ unsigned g_bitset_count = BITSET_WORDS(g->alloc);
+ unsigned bitset_count = BITSET_WORDS(alloc);
+ /* For nodes already in the graph, we just have to grow the adjacency set */
+ for (unsigned i = 0; i < g->alloc; i++) {
+ assert(g->nodes[i].adjacency != NULL);
+ g->nodes[i].adjacency = rerzalloc(g, g->nodes[i].adjacency, BITSET_WORD,
+ g_bitset_count, bitset_count);
+ }
- for (i = 0; i < count; i++) {
- int bitset_count = BITSET_WORDS(count);
+ /* For new nodes, we have to fully initialize them */
+ for (unsigned i = g->alloc; i < alloc; i++) {
+ memset(&g->nodes[i], 0, sizeof(g->nodes[i]));
g->nodes[i].adjacency = rzalloc_array(g, BITSET_WORD, bitset_count);
-
g->nodes[i].adjacency_list_size = 4;
g->nodes[i].adjacency_list =
ralloc_array(g, unsigned int, g->nodes[i].adjacency_list_size);
g->nodes[i].adjacency_count = 0;
g->nodes[i].q_total = 0;
- ra_add_node_adjacency(g, i, i);
+ g->nodes[i].forced_reg = NO_REG;
g->nodes[i].reg = NO_REG;
}
+ /* These are scratch values and don't need to be zeroed. We'll clear them
+ * as part of ra_select() setup.
+ */
+ g->tmp.stack = reralloc(g, g->tmp.stack, unsigned int, alloc);
+ g->tmp.in_stack = reralloc(g, g->tmp.in_stack, BITSET_WORD, bitset_count);
+
+ g->tmp.reg_assigned = reralloc(g, g->tmp.reg_assigned, BITSET_WORD,
+ bitset_count);
+ g->tmp.pq_test = reralloc(g, g->tmp.pq_test, BITSET_WORD, bitset_count);
+ g->tmp.min_q_total = reralloc(g, g->tmp.min_q_total, unsigned int,
+ bitset_count);
+ g->tmp.min_q_node = reralloc(g, g->tmp.min_q_node, unsigned int,
+ bitset_count);
+
+ g->alloc = alloc;
+}
+
+struct ra_graph *
+ra_alloc_interference_graph(struct ra_regs *regs, unsigned int count)
+{
+ struct ra_graph *g;
+
+ g = rzalloc(NULL, struct ra_graph);
+ g->regs = regs;
+ g->count = count;
+ ra_realloc_interference_graph(g, count);
+
return g;
}
+void
+ra_resize_interference_graph(struct ra_graph *g, unsigned int count)
+{
+ g->count = count;
+ if (count > g->alloc)
+ ra_realloc_interference_graph(g, g->alloc * 2);
+}
+
+void ra_set_select_reg_callback(struct ra_graph *g,
+ ra_select_reg_callback callback,
+ void *data)
+{
+ g->select_reg_callback = callback;
+ g->select_reg_callback_data = data;
+}
+
void
ra_set_node_class(struct ra_graph *g,
unsigned int n, unsigned int class)
g->nodes[n].class = class;
}
+unsigned int
+ra_get_node_class(struct ra_graph *g,
+ unsigned int n)
+{
+ return g->nodes[n].class;
+}
+
+unsigned int
+ra_add_node(struct ra_graph *g, unsigned int class)
+{
+ unsigned int n = g->count;
+ ra_resize_interference_graph(g, g->count + 1);
+
+ ra_set_node_class(g, n, class);
+
+ return n;
+}
+
void
ra_add_node_interference(struct ra_graph *g,
unsigned int n1, unsigned int n2)
{
- if (!BITSET_TEST(g->nodes[n1].adjacency, n2)) {
+ assert(n1 < g->count && n2 < g->count);
+ if (n1 != n2 && !BITSET_TEST(g->nodes[n1].adjacency, n2)) {
ra_add_node_adjacency(g, n1, n2);
ra_add_node_adjacency(g, n2, n1);
}
}
-static bool
-pq_test(struct ra_graph *g, unsigned int n)
+void
+ra_reset_node_interference(struct ra_graph *g, unsigned int n)
{
- int n_class = g->nodes[n].class;
+ for (unsigned int i = 0; i < g->nodes[n].adjacency_count; i++)
+ ra_node_remove_adjacency(g, g->nodes[n].adjacency_list[i], n);
+
+ memset(g->nodes[n].adjacency, 0,
+ BITSET_WORDS(g->count) * sizeof(BITSET_WORD));
+ g->nodes[n].adjacency_count = 0;
+}
- return g->nodes[n].q_total < g->regs->classes[n_class]->p;
+static void
+update_pq_info(struct ra_graph *g, unsigned int n)
+{
+ int i = n / BITSET_WORDBITS;
+ int n_class = g->nodes[n].class;
+ if (g->nodes[n].tmp.q_total < g->regs->classes[n_class]->p) {
+ BITSET_SET(g->tmp.pq_test, n);
+ } else if (g->tmp.min_q_total[i] != UINT_MAX) {
+ /* Only update min_q_total and min_q_node if min_q_total != UINT_MAX so
+ * that we don't update while we have stale data and accidentally mark
+ * it as non-stale. Also, in order to remain consistent with the old
+ * naive implementation of the algorithm, we do a lexicographical sort
+ * to ensure that we always choose the node with the highest node index.
+ */
+ if (g->nodes[n].tmp.q_total < g->tmp.min_q_total[i] ||
+ (g->nodes[n].tmp.q_total == g->tmp.min_q_total[i] &&
+ n > g->tmp.min_q_node[i])) {
+ g->tmp.min_q_total[i] = g->nodes[n].tmp.q_total;
+ g->tmp.min_q_node[i] = n;
+ }
+ }
}
static void
-decrement_q(struct ra_graph *g, unsigned int n)
+add_node_to_stack(struct ra_graph *g, unsigned int n)
{
unsigned int i;
int n_class = g->nodes[n].class;
+ assert(!BITSET_TEST(g->tmp.in_stack, n));
+
for (i = 0; i < g->nodes[n].adjacency_count; i++) {
unsigned int n2 = g->nodes[n].adjacency_list[i];
unsigned int n2_class = g->nodes[n2].class;
- if (n != n2 && !g->nodes[n2].in_stack) {
- assert(g->nodes[n2].q_total >= g->regs->classes[n2_class]->q[n_class]);
- g->nodes[n2].q_total -= g->regs->classes[n2_class]->q[n_class];
+ if (!BITSET_TEST(g->tmp.in_stack, n2) &&
+ !BITSET_TEST(g->tmp.reg_assigned, n2)) {
+ assert(g->nodes[n2].tmp.q_total >= g->regs->classes[n2_class]->q[n_class]);
+ g->nodes[n2].tmp.q_total -= g->regs->classes[n2_class]->q[n_class];
+ update_pq_info(g, n2);
}
}
+
+ g->tmp.stack[g->tmp.stack_count] = n;
+ g->tmp.stack_count++;
+ BITSET_SET(g->tmp.in_stack, n);
+
+ /* Flag the min_q_total for n's block as dirty so it gets recalculated */
+ g->tmp.min_q_total[n / BITSET_WORDBITS] = UINT_MAX;
}
/**
{
bool progress = true;
unsigned int stack_optimistic_start = UINT_MAX;
- int i;
+
+ /* Figure out the high bit and bit mask for the first iteration of a loop
+ * over BITSET_WORDs.
+ */
+ const unsigned int top_word_high_bit = (g->count - 1) % BITSET_WORDBITS;
+
+ /* Do a quick pre-pass to set things up */
+ g->tmp.stack_count = 0;
+ for (int i = BITSET_WORDS(g->count) - 1, high_bit = top_word_high_bit;
+ i >= 0; i--, high_bit = BITSET_WORDBITS - 1) {
+ g->tmp.in_stack[i] = 0;
+ g->tmp.reg_assigned[i] = 0;
+ g->tmp.pq_test[i] = 0;
+ g->tmp.min_q_total[i] = UINT_MAX;
+ g->tmp.min_q_node[i] = UINT_MAX;
+ for (int j = high_bit; j >= 0; j--) {
+ unsigned int n = i * BITSET_WORDBITS + j;
+ g->nodes[n].reg = g->nodes[n].forced_reg;
+ g->nodes[n].tmp.q_total = g->nodes[n].q_total;
+ if (g->nodes[n].reg != NO_REG)
+ g->tmp.reg_assigned[i] |= BITSET_BIT(j);
+ update_pq_info(g, n);
+ }
+ }
while (progress) {
- unsigned int best_optimistic_node = ~0;
- unsigned int lowest_q_total = ~0;
+ unsigned int min_q_total = UINT_MAX;
+ unsigned int min_q_node = UINT_MAX;
progress = false;
- for (i = g->count - 1; i >= 0; i--) {
- if (g->nodes[i].in_stack || g->nodes[i].reg != NO_REG)
- continue;
-
- if (pq_test(g, i)) {
- decrement_q(g, i);
- g->stack[g->stack_count] = i;
- g->stack_count++;
- g->nodes[i].in_stack = true;
- progress = true;
- } else {
- unsigned int new_q_total = g->nodes[i].q_total;
- if (new_q_total < lowest_q_total) {
- best_optimistic_node = i;
- lowest_q_total = new_q_total;
- }
- }
+ for (int i = BITSET_WORDS(g->count) - 1, high_bit = top_word_high_bit;
+ i >= 0; i--, high_bit = BITSET_WORDBITS - 1) {
+ BITSET_WORD mask = ~(BITSET_WORD)0 >> (31 - high_bit);
+
+ BITSET_WORD skip = g->tmp.in_stack[i] | g->tmp.reg_assigned[i];
+ if (skip == mask)
+ continue;
+
+ BITSET_WORD pq = g->tmp.pq_test[i] & ~skip;
+ if (pq) {
+ /* In this case, we have stuff we can immediately take off the
+ * stack. This also means that we're guaranteed to make progress
+ * and we don't need to bother updating lowest_q_total because we
+ * know we're going to loop again before attempting to do anything
+ * optimistic.
+ */
+ for (int j = high_bit; j >= 0; j--) {
+ if (pq & BITSET_BIT(j)) {
+ unsigned int n = i * BITSET_WORDBITS + j;
+ assert(n < g->count);
+ add_node_to_stack(g, n);
+ /* add_node_to_stack() may update pq_test for this word so
+ * we need to update our local copy.
+ */
+ pq = g->tmp.pq_test[i] & ~skip;
+ progress = true;
+ }
+ }
+ } else if (!progress) {
+ if (g->tmp.min_q_total[i] == UINT_MAX) {
+ /* The min_q_total and min_q_node are dirty because we added
+ * one of these nodes to the stack. It needs to be
+ * recalculated.
+ */
+ for (int j = high_bit; j >= 0; j--) {
+ if (skip & BITSET_BIT(j))
+ continue;
+
+ unsigned int n = i * BITSET_WORDBITS + j;
+ assert(n < g->count);
+ if (g->nodes[n].tmp.q_total < g->tmp.min_q_total[i]) {
+ g->tmp.min_q_total[i] = g->nodes[n].tmp.q_total;
+ g->tmp.min_q_node[i] = n;
+ }
+ }
+ }
+ if (g->tmp.min_q_total[i] < min_q_total) {
+ min_q_node = g->tmp.min_q_node[i];
+ min_q_total = g->tmp.min_q_total[i];
+ }
+ }
}
- if (!progress && best_optimistic_node != ~0U) {
+ if (!progress && min_q_total != UINT_MAX) {
if (stack_optimistic_start == UINT_MAX)
- stack_optimistic_start = g->stack_count;
+ stack_optimistic_start = g->tmp.stack_count;
- decrement_q(g, best_optimistic_node);
- g->stack[g->stack_count] = best_optimistic_node;
- g->stack_count++;
- g->nodes[best_optimistic_node].in_stack = true;
- progress = true;
+ add_node_to_stack(g, min_q_node);
+ progress = true;
}
}
- g->stack_optimistic_start = stack_optimistic_start;
+ g->tmp.stack_optimistic_start = stack_optimistic_start;
}
static bool
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 &&
+ if (!BITSET_TEST(g->tmp.in_stack, n2) &&
BITSET_TEST(g->regs->regs[r].conflicts, g->nodes[n2].reg)) {
return true;
}
return false;
}
+/* Computes a bitfield of what regs are available for a given register
+ * selection.
+ *
+ * This lets drivers implement a more complicated policy than our simple first
+ * or round robin policies (which don't require knowing the whole bitset)
+ */
+static bool
+ra_compute_available_regs(struct ra_graph *g, unsigned int n, BITSET_WORD *regs)
+{
+ struct ra_class *c = g->regs->classes[g->nodes[n].class];
+
+ /* Populate with the set of regs that are in the node's class. */
+ memcpy(regs, c->regs, BITSET_WORDS(g->regs->count) * sizeof(BITSET_WORD));
+
+ /* Remove any regs that conflict with nodes that we're adjacent to and have
+ * already colored.
+ */
+ for (int i = 0; i < g->nodes[n].adjacency_count; i++) {
+ unsigned int n2 = g->nodes[n].adjacency_list[i];
+ unsigned int r = g->nodes[n2].reg;
+
+ if (!BITSET_TEST(g->tmp.in_stack, n2)) {
+ for (int j = 0; j < BITSET_WORDS(g->regs->count); j++)
+ regs[j] &= ~g->regs->regs[r].conflicts[j];
+ }
+ }
+
+ for (int i = 0; i < BITSET_WORDS(g->regs->count); i++) {
+ if (regs[i])
+ return true;
+ }
+
+ return false;
+}
+
/**
* Pops nodes from the stack back into the graph, coloring them with
* registers as they go.
ra_select(struct ra_graph *g)
{
int start_search_reg = 0;
+ BITSET_WORD *select_regs = NULL;
+
+ if (g->select_reg_callback)
+ select_regs = malloc(BITSET_WORDS(g->regs->count) * sizeof(BITSET_WORD));
- while (g->stack_count != 0) {
+ while (g->tmp.stack_count != 0) {
unsigned int ri;
unsigned int r = -1;
- int n = g->stack[g->stack_count - 1];
+ int n = g->tmp.stack[g->tmp.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 (ri = 0; ri < g->regs->count; ri++) {
- r = (start_search_reg + ri) % g->regs->count;
- if (!reg_belongs_to_class(r, c))
- continue;
-
- if (!ra_any_neighbors_conflict(g, n, r))
- break;
- }
-
/* set this to false even if we return here so that
* ra_get_best_spill_node() considers this node later.
*/
- g->nodes[n].in_stack = false;
+ BITSET_CLEAR(g->tmp.in_stack, n);
- if (ri == g->regs->count)
- return false;
+ if (g->select_reg_callback) {
+ if (!ra_compute_available_regs(g, n, select_regs)) {
+ free(select_regs);
+ return false;
+ }
+
+ r = g->select_reg_callback(n, select_regs, g->select_reg_callback_data);
+ } else {
+ /* Find the lowest-numbered reg which is not used by a member
+ * of the graph adjacent to us.
+ */
+ for (ri = 0; ri < g->regs->count; ri++) {
+ r = (start_search_reg + ri) % g->regs->count;
+ if (!reg_belongs_to_class(r, c))
+ continue;
+
+ if (!ra_any_neighbors_conflict(g, n, r))
+ break;
+ }
+
+ if (ri >= g->regs->count)
+ return false;
+ }
g->nodes[n].reg = r;
- g->stack_count--;
+ g->tmp.stack_count--;
/* Rotate the starting point except for any nodes above the lowest
* optimistically colorable node. The likelihood that we will succeed
* dense packing strategy.
*/
if (g->regs->round_robin &&
- g->stack_count - 1 <= g->stack_optimistic_start)
+ g->tmp.stack_count - 1 <= g->tmp.stack_optimistic_start)
start_search_reg = r + 1;
}
+ free(select_regs);
+
return true;
}
unsigned int
ra_get_node_reg(struct ra_graph *g, unsigned int n)
{
- return g->nodes[n].reg;
+ if (g->nodes[n].forced_reg != NO_REG)
+ return g->nodes[n].forced_reg;
+ else
+ return g->nodes[n].reg;
}
/**
void
ra_set_node_reg(struct ra_graph *g, unsigned int n, unsigned int reg)
{
- g->nodes[n].reg = reg;
- g->nodes[n].in_stack = false;
+ g->nodes[n].forced_reg = reg;
}
static float
*/
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);
- }
+ 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;
float benefit;
if (cost <= 0.0f)
- continue;
+ continue;
- if (g->nodes[n].in_stack)
+ if (BITSET_TEST(g->tmp.in_stack, n))
continue;
benefit = ra_get_spill_benefit(g, n);
if (benefit / cost > best_benefit) {
- best_benefit = benefit / cost;
- best_node = n;
+ best_benefit = benefit / cost;
+ best_node = n;
}
}
projects / mesa.git / blobdiff