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/*
* Oracle Linux DTrace.
* Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
* Licensed under the Universal Permissive License v 1.0 as shown at
* http://oss.oracle.com/licenses/upl.
*/
#include <sys/types.h>
#include <sys/bitmap.h>
#include <assert.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <dt_debug.h>
#include <dt_regset.h>
dt_regset_t *
dt_regset_create(ulong_t size, dt_cg_spill_f stf, dt_cg_spill_f ldf)
{
dt_regset_t *drp = malloc(sizeof(dt_regset_t));
if (drp == NULL)
return NULL;
size++; /* for %r0 */
drp->dr_size = size;
drp->dr_spill_store = stf;
drp->dr_spill_load = ldf;
drp->dr_active = malloc(BT_SIZEOFMAP(size));
drp->dr_spilled = malloc(BT_SIZEOFMAP(size));
if (drp->dr_active == NULL || drp->dr_spilled == NULL) {
free(drp->dr_active);
free(drp->dr_spilled);
free(drp);
return NULL;
}
dt_regset_reset(drp);
return drp;
}
void
dt_regset_destroy(dt_regset_t *drp)
{
free(drp->dr_active);
free(drp->dr_spilled);
free(drp);
}
void
dt_regset_reset(dt_regset_t *drp)
{
memset(drp->dr_active, 0, BT_SIZEOFMAP(drp->dr_size));
memset(drp->dr_spilled, 0, BT_SIZEOFMAP(drp->dr_size));
}
int
dt_regset_alloc(dt_regset_t *drp)
{
int reg;
for (reg = drp->dr_size - 1; reg > 0; reg--) {
if (BT_TEST(drp->dr_active, reg) == 0) {
BT_SET(drp->dr_active, reg);
return reg;
}
}
for (reg = drp->dr_size - 1; reg > 0; reg--) {
if (BT_TEST(drp->dr_spilled, reg) == 0) {
drp->dr_spill_store(reg);
BT_SET(drp->dr_spilled, reg);
return reg;
}
}
return -1; /* no available registers */
}
/*
* Allocate a specific register.
*/
int
dt_regset_xalloc(dt_regset_t *drp, int reg)
{
assert(reg >= 0 && reg < drp->dr_size);
if (BT_TEST(drp->dr_active, reg) != 0) {
if (BT_TEST(drp->dr_spilled, reg) != 0)
return -1; /* register in use (and spilled)*/
drp->dr_spill_store(reg);
BT_SET(drp->dr_spilled, reg);
}
BT_SET(drp->dr_active, reg);
return 0;
}
void
dt_regset_free(dt_regset_t *drp, int reg)
{
assert(reg >= 0 && reg < drp->dr_size);
assert(BT_TEST(drp->dr_active, reg) != 0);
if (BT_TEST(drp->dr_spilled, reg) != 0) {
drp->dr_spill_load(reg);
BT_CLEAR(drp->dr_spilled, reg);
return;
}
BT_CLEAR(drp->dr_active, reg);
}
/*
* Allocate %r1 through %r5 for use as function call arguments in BPF.
*/
int
dt_regset_xalloc_args(dt_regset_t *drp)
{
int reg;
for (reg = 1; reg <= 5; reg++) {
if (dt_regset_xalloc(drp, reg) == -1) {
while (--reg > 0)
dt_regset_free(drp, reg);
return -1; /* register in use */
}
}
return 0;
}
/*
* Free %r1 through %r5 after they were used as function call arguments in BPF.
*/
void
dt_regset_free_args(dt_regset_t *drp)
{
int reg;
for (reg = 1; reg <= 5; reg++)
dt_regset_free(drp, reg);
}
#define DT_PAD_MAX 40
#define DT_PAD(n) ((n) > DT_PAD_MAX ? 0 : DT_PAD_MAX - (n))
/*
* Dump the current register allocation.
*/
void
dt_regset_dump(dt_regset_t *drp, const char *pref)
{
int reg, n;
n = fprintf(stderr, "%s: Regset: ", pref);
fprintf(stderr, "%*s", DT_PAD(n), "");
for (reg = 0; reg < drp->dr_size; reg++) {
fprintf(stderr, " %c%c",
BT_TEST(drp->dr_active, reg) ? '0' + reg : '.',
BT_TEST(drp->dr_spilled, reg) ? 's' : '.');
}
fprintf(stderr, "\n");
}
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