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tcg: Introduce TYPE_CONST temporaries 

These will hold a single constant for the duration of the TB.
They are hashed, so that each value has one temp across the TB.

Not used yet, this is all infrastructure.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2020-03-29 18:55:52 -07:00
parent 54795544e4
commit c0522136ad
3 changed files with 211 additions and 50 deletions
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24
include/tcg/tcg.h
View File

@ -492,6 +492,8 @@ typedef enum TCGTempKind {
TEMP_GLOBAL,
/* Temp is in a fixed register. */
TEMP_FIXED,
/* Temp is a fixed constant. */
TEMP_CONST,
} TCGTempKind;
typedef struct TCGTemp {
@ -665,6 +667,7 @@ struct TCGContext {
QSIMPLEQ_HEAD(, TCGOp) plugin_ops;
#endif
GHashTable *const_table[TCG_TYPE_COUNT];
TCGTempSet free_temps[TCG_TYPE_COUNT * 2];
TCGTemp temps[TCG_MAX_TEMPS]; /* globals first, temps after */
@ -681,7 +684,7 @@ struct TCGContext {
static inline bool temp_readonly(TCGTemp *ts)
{
return ts->kind == TEMP_FIXED;
return ts->kind >= TEMP_FIXED;
}
extern TCGContext tcg_init_ctx;
@ -1079,6 +1082,7 @@ TCGOp *tcg_op_insert_after(TCGContext *s, TCGOp *op, TCGOpcode opc);
void tcg_optimize(TCGContext *s);
/* Allocate a new temporary and initialize it with a constant. */
TCGv_i32 tcg_const_i32(int32_t val);
TCGv_i64 tcg_const_i64(int64_t val);
TCGv_i32 tcg_const_local_i32(int32_t val);
@ -1088,6 +1092,24 @@ TCGv_vec tcg_const_ones_vec(TCGType);
TCGv_vec tcg_const_zeros_vec_matching(TCGv_vec);
TCGv_vec tcg_const_ones_vec_matching(TCGv_vec);
/*
* Locate or create a read-only temporary that is a constant.
* This kind of temporary need not and should not be freed.
*/
TCGTemp *tcg_constant_internal(TCGType type, int64_t val);
static inline TCGv_i32 tcg_constant_i32(int32_t val)
{
return temp_tcgv_i32(tcg_constant_internal(TCG_TYPE_I32, val));
}
static inline TCGv_i64 tcg_constant_i64(int64_t val)
{
return temp_tcgv_i64(tcg_constant_internal(TCG_TYPE_I64, val));
}
TCGv_vec tcg_constant_vec(TCGType type, unsigned vece, int64_t val);
#if UINTPTR_MAX == UINT32_MAX
# define tcg_const_ptr(x) ((TCGv_ptr)tcg_const_i32((intptr_t)(x)))
# define tcg_const_local_ptr(x) ((TCGv_ptr)tcg_const_local_i32((intptr_t)(x)))

13
tcg/optimize.c
View File

@ -99,8 +99,17 @@ static void init_ts_info(TempOptInfo *infos,
ts->state_ptr = ti;
ti->next_copy = ts;
ti->prev_copy = ts;
ti->is_const = false;
ti->mask = -1;
if (ts->kind == TEMP_CONST) {
ti->is_const = true;
ti->val = ti->mask = ts->val;
if (TCG_TARGET_REG_BITS > 32 && ts->type == TCG_TYPE_I32) {
/* High bits of a 32-bit quantity are garbage. */
ti->mask |= ~0xffffffffull;
}
} else {
ti->is_const = false;
ti->mask = -1;
}
set_bit(idx, temps_used->l);
}
}

224
tcg/tcg.c
View File

@ -1184,6 +1184,13 @@ void tcg_func_start(TCGContext *s)
/* No temps have been previously allocated for size or locality. */
memset(s->free_temps, 0, sizeof(s->free_temps));
/* No constant temps have been previously allocated. */
for (int i = 0; i < TCG_TYPE_COUNT; ++i) {
if (s->const_table[i]) {
g_hash_table_remove_all(s->const_table[i]);
}
}
s->nb_ops = 0;
s->nb_labels = 0;
s->current_frame_offset = s->frame_start;
@ -1255,13 +1262,19 @@ TCGTemp *tcg_global_mem_new_internal(TCGType type, TCGv_ptr base,
bigendian = 1;
#endif
if (base_ts->kind != TEMP_FIXED) {
switch (base_ts->kind) {
case TEMP_FIXED:
break;
case TEMP_GLOBAL:
/* We do not support double-indirect registers. */
tcg_debug_assert(!base_ts->indirect_reg);
base_ts->indirect_base = 1;
s->nb_indirects += (TCG_TARGET_REG_BITS == 32 && type == TCG_TYPE_I64
? 2 : 1);
indirect_reg = 1;
break;
default:
g_assert_not_reached();
}
if (TCG_TARGET_REG_BITS == 32 && type == TCG_TYPE_I64) {
@ -1386,6 +1399,11 @@ void tcg_temp_free_internal(TCGTemp *ts)
TCGContext *s = tcg_ctx;
int k, idx;
/* In order to simplify users of tcg_constant_*, silently ignore free. */
if (ts->kind == TEMP_CONST) {
return;
}
#if defined(CONFIG_DEBUG_TCG)
s->temps_in_use--;
if (s->temps_in_use < 0) {
@ -1402,6 +1420,60 @@ void tcg_temp_free_internal(TCGTemp *ts)
set_bit(idx, s->free_temps[k].l);
}
TCGTemp *tcg_constant_internal(TCGType type, int64_t val)
{
TCGContext *s = tcg_ctx;
GHashTable *h = s->const_table[type];
TCGTemp *ts;
if (h == NULL) {
h = g_hash_table_new(g_int64_hash, g_int64_equal);
s->const_table[type] = h;
}
ts = g_hash_table_lookup(h, &val);
if (ts == NULL) {
ts = tcg_temp_alloc(s);
if (TCG_TARGET_REG_BITS == 32 && type == TCG_TYPE_I64) {
TCGTemp *ts2 = tcg_temp_alloc(s);
ts->base_type = TCG_TYPE_I64;
ts->type = TCG_TYPE_I32;
ts->kind = TEMP_CONST;
ts->temp_allocated = 1;
/*
* Retain the full value of the 64-bit constant in the low
* part, so that the hash table works. Actual uses will
* truncate the value to the low part.
*/
ts->val = val;
tcg_debug_assert(ts2 == ts + 1);
ts2->base_type = TCG_TYPE_I64;
ts2->type = TCG_TYPE_I32;
ts2->kind = TEMP_CONST;
ts2->temp_allocated = 1;
ts2->val = val >> 32;
} else {
ts->base_type = type;
ts->type = type;
ts->kind = TEMP_CONST;
ts->temp_allocated = 1;
ts->val = val;
}
g_hash_table_insert(h, &ts->val, ts);
}
return ts;
}
TCGv_vec tcg_constant_vec(TCGType type, unsigned vece, int64_t val)
{
val = dup_const(vece, val);
return temp_tcgv_vec(tcg_constant_internal(type, val));
}
TCGv_i32 tcg_const_i32(int32_t val)
{
TCGv_i32 t0;
@ -1937,6 +2009,9 @@ static void tcg_reg_alloc_start(TCGContext *s)
TCGTempVal val = TEMP_VAL_MEM;
switch (ts->kind) {
case TEMP_CONST:
val = TEMP_VAL_CONST;
break;
case TEMP_FIXED:
val = TEMP_VAL_REG;
break;
@ -1973,6 +2048,26 @@ static char *tcg_get_arg_str_ptr(TCGContext *s, char *buf, int buf_size,
case TEMP_NORMAL:
snprintf(buf, buf_size, "tmp%d", idx - s->nb_globals);
break;
case TEMP_CONST:
switch (ts->type) {
case TCG_TYPE_I32:
snprintf(buf, buf_size, "$0x%x", (int32_t)ts->val);
break;
#if TCG_TARGET_REG_BITS > 32
case TCG_TYPE_I64:
snprintf(buf, buf_size, "$0x%" PRIx64, ts->val);
break;
#endif
case TCG_TYPE_V64:
case TCG_TYPE_V128:
case TCG_TYPE_V256:
snprintf(buf, buf_size, "v%d$0x%" PRIx64,
64 << (ts->type - TCG_TYPE_V64), ts->val);
break;
default:
g_assert_not_reached();
}
break;
}
return buf;
}
@ -2574,6 +2669,7 @@ static void la_bb_end(TCGContext *s, int ng, int nt)
state = TS_DEAD | TS_MEM;
break;
case TEMP_NORMAL:
case TEMP_CONST:
state = TS_DEAD;
break;
default:
@ -2608,14 +2704,24 @@ static void la_bb_sync(TCGContext *s, int ng, int nt)
la_global_sync(s, ng);
for (int i = ng; i < nt; ++i) {
if (s->temps[i].kind == TEMP_LOCAL) {
int state = s->temps[i].state;
s->temps[i].state = state | TS_MEM;
TCGTemp *ts = &s->temps[i];
int state;
switch (ts->kind) {
case TEMP_LOCAL:
state = ts->state;
ts->state = state | TS_MEM;
if (state != TS_DEAD) {
continue;
}
} else {
break;
case TEMP_NORMAL:
s->temps[i].state = TS_DEAD;
break;
case TEMP_CONST:
continue;
default:
g_assert_not_reached();
}
la_reset_pref(&s->temps[i]);
}
@ -3254,15 +3360,28 @@ static void temp_load(TCGContext *, TCGTemp *, TCGRegSet, TCGRegSet, TCGRegSet);
mark it free; otherwise mark it dead. */
static void temp_free_or_dead(TCGContext *s, TCGTemp *ts, int free_or_dead)
{
if (temp_readonly(ts)) {
TCGTempVal new_type;
switch (ts->kind) {
case TEMP_FIXED:
return;
case TEMP_GLOBAL:
case TEMP_LOCAL:
new_type = TEMP_VAL_MEM;
break;
case TEMP_NORMAL:
new_type = free_or_dead < 0 ? TEMP_VAL_MEM : TEMP_VAL_DEAD;
break;
case TEMP_CONST:
new_type = TEMP_VAL_CONST;
break;
default:
g_assert_not_reached();
}
if (ts->val_type == TEMP_VAL_REG) {
s->reg_to_temp[ts->reg] = NULL;
}
ts->val_type = (free_or_dead < 0
|| ts->kind != TEMP_NORMAL
? TEMP_VAL_MEM : TEMP_VAL_DEAD);
ts->val_type = new_type;
}
/* Mark a temporary as dead. */
@ -3278,10 +3397,7 @@ static inline void temp_dead(TCGContext *s, TCGTemp *ts)
static void temp_sync(TCGContext *s, TCGTemp *ts, TCGRegSet allocated_regs,
TCGRegSet preferred_regs, int free_or_dead)
{
if (temp_readonly(ts)) {
return;
}
if (!ts->mem_coherent) {
if (!temp_readonly(ts) && !ts->mem_coherent) {
if (!ts->mem_allocated) {
temp_allocate_frame(s, ts);
}
@ -3499,12 +3615,22 @@ static void tcg_reg_alloc_bb_end(TCGContext *s, TCGRegSet allocated_regs)
for (i = s->nb_globals; i < s->nb_temps; i++) {
TCGTemp *ts = &s->temps[i];
if (ts->kind == TEMP_LOCAL) {
switch (ts->kind) {
case TEMP_LOCAL:
temp_save(s, ts, allocated_regs);
} else {
break;
case TEMP_NORMAL:
/* The liveness analysis already ensures that temps are dead.
Keep an tcg_debug_assert for safety. */
tcg_debug_assert(ts->val_type == TEMP_VAL_DEAD);
break;
case TEMP_CONST:
/* Similarly, we should have freed any allocated register. */
tcg_debug_assert(ts->val_type == TEMP_VAL_CONST);
break;
default:
g_assert_not_reached();
}
}
@ -3525,10 +3651,17 @@ static void tcg_reg_alloc_cbranch(TCGContext *s, TCGRegSet allocated_regs)
* The liveness analysis already ensures that temps are dead.
* Keep tcg_debug_asserts for safety.
*/
if (ts->kind == TEMP_LOCAL) {
switch (ts->kind) {
case TEMP_LOCAL:
tcg_debug_assert(ts->val_type != TEMP_VAL_REG || ts->mem_coherent);
} else {
break;
case TEMP_NORMAL:
tcg_debug_assert(ts->val_type == TEMP_VAL_DEAD);
break;
case TEMP_CONST:
break;
default:
g_assert_not_reached();
}
}
}
@ -3819,45 +3952,42 @@ static void tcg_reg_alloc_op(TCGContext *s, const TCGOp *op)
i_preferred_regs = o_preferred_regs = 0;
if (arg_ct->ialias) {
o_preferred_regs = op->output_pref[arg_ct->alias_index];
if (ts->kind == TEMP_FIXED) {
/* if fixed register, we must allocate a new register
if the alias is not the same register */
if (arg != op->args[arg_ct->alias_index]) {
goto allocate_in_reg;
}
} else {
/* if the input is aliased to an output and if it is
not dead after the instruction, we must allocate
a new register and move it */
if (!IS_DEAD_ARG(i)) {
goto allocate_in_reg;
}
/* check if the current register has already been allocated
for another input aliased to an output */
if (ts->val_type == TEMP_VAL_REG) {
int k2, i2;
reg = ts->reg;
for (k2 = 0 ; k2 < k ; k2++) {
i2 = def->args_ct[nb_oargs + k2].sort_index;
if (def->args_ct[i2].ialias && reg == new_args[i2]) {
goto allocate_in_reg;
}
/*
* If the input is readonly, then it cannot also be an
* output and aliased to itself. If the input is not
* dead after the instruction, we must allocate a new
* register and move it.
*/
if (temp_readonly(ts) || !IS_DEAD_ARG(i)) {
goto allocate_in_reg;
}
/*
* Check if the current register has already been allocated
* for another input aliased to an output.
*/
if (ts->val_type == TEMP_VAL_REG) {
reg = ts->reg;
for (int k2 = 0; k2 < k; k2++) {
int i2 = def->args_ct[nb_oargs + k2].sort_index;
if (def->args_ct[i2].ialias && reg == new_args[i2]) {
goto allocate_in_reg;
}
}
i_preferred_regs = o_preferred_regs;
}
i_preferred_regs = o_preferred_regs;
}
temp_load(s, ts, arg_ct->regs, i_allocated_regs, i_preferred_regs);
reg = ts->reg;
if (tcg_regset_test_reg(arg_ct->regs, reg)) {
/* nothing to do : the constraint is satisfied */
} else {
allocate_in_reg:
/* allocate a new register matching the constraint
and move the temporary register into it */
if (!tcg_regset_test_reg(arg_ct->regs, reg)) {
allocate_in_reg:
/*
* Allocate a new register matching the constraint
* and move the temporary register into it.
*/
temp_load(s, ts, tcg_target_available_regs[ts->type],
i_allocated_regs, 0);
reg = tcg_reg_alloc(s, arg_ct->regs, i_allocated_regs,