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tcg: Compress liveness data to 16 bits 

This reduces both memory usage and per-insn cacheline usage
during code generation.

Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Richard Henderson <rth@twiddle.net>
This commit is contained in:
Richard Henderson 2016-06-22 15:46:09 -07:00
parent 51009170d8
commit a1b3c48d2b
2 changed files with 32 additions and 42 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

58
tcg/tcg.c
View File

@ -1341,7 +1341,7 @@ static inline void tcg_la_bb_end(TCGContext *s, uint8_t *dead_temps,
} }
} }
/* Liveness analysis : update the opc_dead_args array to tell if a /* Liveness analysis : update the opc_arg_life array to tell if a
given input arguments is dead. Instructions updating dead given input arguments is dead. Instructions updating dead
temporaries are removed. */ temporaries are removed. */
static void tcg_liveness_analysis(TCGContext *s) static void tcg_liveness_analysis(TCGContext *s)
@ -1350,9 +1350,8 @@ static void tcg_liveness_analysis(TCGContext *s)
int oi, oi_prev, nb_ops; int oi, oi_prev, nb_ops;
nb_ops = s->gen_next_op_idx; nb_ops = s->gen_next_op_idx;
s->op_dead_args = tcg_malloc(nb_ops * sizeof(uint16_t)); s->op_arg_life = tcg_malloc(nb_ops * sizeof(TCGLifeData));
s->op_sync_args = tcg_malloc(nb_ops * sizeof(uint8_t));
dead_temps = tcg_malloc(s->nb_temps); dead_temps = tcg_malloc(s->nb_temps);
mem_temps = tcg_malloc(s->nb_temps); mem_temps = tcg_malloc(s->nb_temps);
tcg_la_func_end(s, dead_temps, mem_temps); tcg_la_func_end(s, dead_temps, mem_temps);
@ -1361,8 +1360,7 @@ static void tcg_liveness_analysis(TCGContext *s)
int i, nb_iargs, nb_oargs; int i, nb_iargs, nb_oargs;
TCGOpcode opc_new, opc_new2; TCGOpcode opc_new, opc_new2;
bool have_opc_new2; bool have_opc_new2;
uint16_t dead_args; TCGLifeData arg_life = 0;
uint8_t sync_args;
TCGArg arg; TCGArg arg;
TCGOp * const op = &s->gen_op_buf[oi]; TCGOp * const op = &s->gen_op_buf[oi];
@ -1394,15 +1392,13 @@ static void tcg_liveness_analysis(TCGContext *s)
do_not_remove_call: do_not_remove_call:
/* output args are dead */ /* output args are dead */
dead_args = 0;
sync_args = 0;
for (i = 0; i < nb_oargs; i++) { for (i = 0; i < nb_oargs; i++) {
arg = args[i]; arg = args[i];
if (dead_temps[arg]) { if (dead_temps[arg]) {
dead_args |= (1 << i); arg_life |= DEAD_ARG << i;
} }
if (mem_temps[arg]) { if (mem_temps[arg]) {
sync_args |= (1 << i); arg_life |= SYNC_ARG << i;
} }
dead_temps[arg] = 1; dead_temps[arg] = 1;
mem_temps[arg] = 0; mem_temps[arg] = 0;
@ -1423,7 +1419,7 @@ static void tcg_liveness_analysis(TCGContext *s)
arg = args[i]; arg = args[i];
if (arg != TCG_CALL_DUMMY_ARG) { if (arg != TCG_CALL_DUMMY_ARG) {
if (dead_temps[arg]) { if (dead_temps[arg]) {
dead_args |= (1 << i); arg_life |= DEAD_ARG << i;
} }
} }
} }
@ -1432,8 +1428,6 @@ static void tcg_liveness_analysis(TCGContext *s)
arg = args[i]; arg = args[i];
dead_temps[arg] = 0; dead_temps[arg] = 0;
} }
s->op_dead_args[oi] = dead_args;
s->op_sync_args[oi] = sync_args;
} }
} }
break; break;
@ -1544,15 +1538,13 @@ static void tcg_liveness_analysis(TCGContext *s)
} else { } else {
do_not_remove: do_not_remove:
/* output args are dead */ /* output args are dead */
dead_args = 0;
sync_args = 0;
for (i = 0; i < nb_oargs; i++) { for (i = 0; i < nb_oargs; i++) {
arg = args[i]; arg = args[i];
if (dead_temps[arg]) { if (dead_temps[arg]) {
dead_args |= (1 << i); arg_life |= DEAD_ARG << i;
} }
if (mem_temps[arg]) { if (mem_temps[arg]) {
sync_args |= (1 << i); arg_life |= SYNC_ARG << i;
} }
dead_temps[arg] = 1; dead_temps[arg] = 1;
mem_temps[arg] = 0; mem_temps[arg] = 0;
@ -1570,7 +1562,7 @@ static void tcg_liveness_analysis(TCGContext *s)
for (i = nb_oargs; i < nb_oargs + nb_iargs; i++) { for (i = nb_oargs; i < nb_oargs + nb_iargs; i++) {
arg = args[i]; arg = args[i];
if (dead_temps[arg]) { if (dead_temps[arg]) {
dead_args |= (1 << i); arg_life |= DEAD_ARG << i;
} }
} }
/* input arguments are live for preceding opcodes */ /* input arguments are live for preceding opcodes */
@ -1578,11 +1570,10 @@ static void tcg_liveness_analysis(TCGContext *s)
arg = args[i]; arg = args[i];
dead_temps[arg] = 0; dead_temps[arg] = 0;
} }
s->op_dead_args[oi] = dead_args;
s->op_sync_args[oi] = sync_args;
} }
break; break;
} }
s->op_arg_life[oi] = arg_life;
} }
} }
#else #else
@ -1921,11 +1912,11 @@ static void tcg_reg_alloc_bb_end(TCGContext *s, TCGRegSet allocated_regs)
save_globals(s, allocated_regs); save_globals(s, allocated_regs);
} }
#define IS_DEAD_ARG(n) ((dead_args >> (n)) & 1) #define IS_DEAD_ARG(n) (arg_life & (DEAD_ARG << (n)))
#define NEED_SYNC_ARG(n) ((sync_args >> (n)) & 1) #define NEED_SYNC_ARG(n) (arg_life & (SYNC_ARG << (n)))
static void tcg_reg_alloc_movi(TCGContext *s, const TCGArg *args, static void tcg_reg_alloc_movi(TCGContext *s, const TCGArg *args,
uint16_t dead_args, uint8_t sync_args) TCGLifeData arg_life)
{ {
TCGTemp *ots; TCGTemp *ots;
tcg_target_ulong val; tcg_target_ulong val;
@ -1954,8 +1945,7 @@ static void tcg_reg_alloc_movi(TCGContext *s, const TCGArg *args,
} }
static void tcg_reg_alloc_mov(TCGContext *s, const TCGOpDef *def, static void tcg_reg_alloc_mov(TCGContext *s, const TCGOpDef *def,
const TCGArg *args, uint16_t dead_args, const TCGArg *args, TCGLifeData arg_life)
uint8_t sync_args)
{ {
TCGRegSet allocated_regs; TCGRegSet allocated_regs;
TCGTemp *ts, *ots; TCGTemp *ts, *ots;
@ -2040,8 +2030,7 @@ static void tcg_reg_alloc_mov(TCGContext *s, const TCGOpDef *def,
static void tcg_reg_alloc_op(TCGContext *s, static void tcg_reg_alloc_op(TCGContext *s,
const TCGOpDef *def, TCGOpcode opc, const TCGOpDef *def, TCGOpcode opc,
const TCGArg *args, uint16_t dead_args, const TCGArg *args, TCGLifeData arg_life)
uint8_t sync_args)
{ {
TCGRegSet allocated_regs; TCGRegSet allocated_regs;
int i, k, nb_iargs, nb_oargs; int i, k, nb_iargs, nb_oargs;
@ -2206,8 +2195,7 @@ static void tcg_reg_alloc_op(TCGContext *s,
#endif #endif
static void tcg_reg_alloc_call(TCGContext *s, int nb_oargs, int nb_iargs, static void tcg_reg_alloc_call(TCGContext *s, int nb_oargs, int nb_iargs,
const TCGArg * const args, uint16_t dead_args, const TCGArg * const args, TCGLifeData arg_life)
uint8_t sync_args)
{ {
int flags, nb_regs, i; int flags, nb_regs, i;
TCGReg reg; TCGReg reg;
@ -2427,8 +2415,7 @@ int tcg_gen_code(TCGContext *s, TranslationBlock *tb)
TCGArg * const args = &s->gen_opparam_buf[op->args]; TCGArg * const args = &s->gen_opparam_buf[op->args];
TCGOpcode opc = op->opc; TCGOpcode opc = op->opc;
const TCGOpDef *def = &tcg_op_defs[opc]; const TCGOpDef *def = &tcg_op_defs[opc];
uint16_t dead_args = s->op_dead_args[oi]; TCGLifeData arg_life = s->op_arg_life[oi];
uint8_t sync_args = s->op_sync_args[oi];
oi_next = op->next; oi_next = op->next;
#ifdef CONFIG_PROFILER #ifdef CONFIG_PROFILER
@ -2438,11 +2425,11 @@ int tcg_gen_code(TCGContext *s, TranslationBlock *tb)
switch (opc) { switch (opc) {
case INDEX_op_mov_i32: case INDEX_op_mov_i32:
case INDEX_op_mov_i64: case INDEX_op_mov_i64:
tcg_reg_alloc_mov(s, def, args, dead_args, sync_args); tcg_reg_alloc_mov(s, def, args, arg_life);
break; break;
case INDEX_op_movi_i32: case INDEX_op_movi_i32:
case INDEX_op_movi_i64: case INDEX_op_movi_i64:
tcg_reg_alloc_movi(s, args, dead_args, sync_args); tcg_reg_alloc_movi(s, args, arg_life);
break; break;
case INDEX_op_insn_start: case INDEX_op_insn_start:
if (num_insns >= 0) { if (num_insns >= 0) {
@ -2467,8 +2454,7 @@ int tcg_gen_code(TCGContext *s, TranslationBlock *tb)
tcg_out_label(s, arg_label(args[0]), s->code_ptr); tcg_out_label(s, arg_label(args[0]), s->code_ptr);
break; break;
case INDEX_op_call: case INDEX_op_call:
tcg_reg_alloc_call(s, op->callo, op->calli, args, tcg_reg_alloc_call(s, op->callo, op->calli, args, arg_life);
dead_args, sync_args);
break; break;
default: default:
/* Sanity check that we've not introduced any unhandled opcodes. */ /* Sanity check that we've not introduced any unhandled opcodes. */
@ -2478,7 +2464,7 @@ int tcg_gen_code(TCGContext *s, TranslationBlock *tb)
/* Note: in order to speed up the code, it would be much /* Note: in order to speed up the code, it would be much
faster to have specialized register allocator functions for faster to have specialized register allocator functions for
some common argument patterns */ some common argument patterns */
tcg_reg_alloc_op(s, def, opc, args, dead_args, sync_args); tcg_reg_alloc_op(s, def, opc, args, arg_life);
break; break;
} }
#ifdef CONFIG_DEBUG_TCG #ifdef CONFIG_DEBUG_TCG

16
tcg/tcg.h
View File

@ -575,6 +575,14 @@ typedef struct TCGTempSet {
unsigned long l[BITS_TO_LONGS(TCG_MAX_TEMPS)]; unsigned long l[BITS_TO_LONGS(TCG_MAX_TEMPS)];
} TCGTempSet; } TCGTempSet;
/* While we limit helpers to 6 arguments, for 32-bit hosts, with padding,
this imples a max of 6*2 (64-bit in) + 2 (64-bit out) = 14 operands.
There are never more than 2 outputs, which means that we can store all
dead + sync data within 16 bits. */
#define DEAD_ARG 4
#define SYNC_ARG 1
typedef uint16_t TCGLifeData;
typedef struct TCGOp { typedef struct TCGOp {
TCGOpcode opc : 8; TCGOpcode opc : 8;
@ -608,12 +616,8 @@ struct TCGContext {
uintptr_t *tb_jmp_target_addr; /* tb->jmp_target_addr if !USE_DIRECT_JUMP */ uintptr_t *tb_jmp_target_addr; /* tb->jmp_target_addr if !USE_DIRECT_JUMP */
/* liveness analysis */ /* liveness analysis */
uint16_t *op_dead_args; /* for each operation, each bit tells if the TCGLifeData *op_arg_life;
corresponding argument is dead */
uint8_t *op_sync_args; /* for each operation, each bit tells if the
corresponding output argument needs to be
sync to memory. */
TCGRegSet reserved_regs; TCGRegSet reserved_regs;
intptr_t current_frame_offset; intptr_t current_frame_offset;
intptr_t frame_start; intptr_t frame_start;