From 0ec9eabc7f6020418e1f3b3273d1dd701f7f87f9 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Thu, 19 Sep 2013 12:16:45 -0700 Subject: tcg: Use bitmaps for free temporaries We previously allocated 32-bits per temp for the next_free_temp entry. We now allocate 4 bits per temp across the 4 bitmaps. Using a linked list meant that if a translator is tweeked, resulting in temps being freed in a different order, that would have follow-on effects throughout the TB. Always allocating the lowest free temp means that follow-on effects are minimized, which can make it easier to diff output when debugging the translators. Reviewed-by: Peter Maydell Reviewed-by: Aurelien Jarno Signed-off-by: Richard Henderson --- tcg/tcg.c | 32 +++++++++++++++----------------- tcg/tcg.h | 11 ++++++----- 2 files changed, 21 insertions(+), 22 deletions(-) (limited to 'tcg') diff --git a/tcg/tcg.c b/tcg/tcg.c index 66d3f3de80..712438ced8 100644 --- a/tcg/tcg.c +++ b/tcg/tcg.c @@ -357,11 +357,12 @@ void tcg_set_frame(TCGContext *s, int reg, intptr_t start, intptr_t size) void tcg_func_start(TCGContext *s) { - int i; tcg_pool_reset(s); s->nb_temps = s->nb_globals; - for(i = 0; i < (TCG_TYPE_COUNT * 2); i++) - s->first_free_temp[i] = -1; + + /* No temps have been previously allocated for size or locality. */ + memset(s->free_temps, 0, sizeof(s->free_temps)); + s->labels = tcg_malloc(sizeof(TCGLabel) * TCG_MAX_LABELS); s->nb_labels = 0; s->current_frame_offset = s->frame_start; @@ -503,16 +504,15 @@ static inline int tcg_temp_new_internal(TCGType type, int temp_local) TCGTemp *ts; int idx, k; - k = type; - if (temp_local) - k += TCG_TYPE_COUNT; - idx = s->first_free_temp[k]; - if (idx != -1) { - /* There is already an available temp with the - right type */ + k = type + (temp_local ? TCG_TYPE_COUNT : 0); + idx = find_first_bit(s->free_temps[k].l, TCG_MAX_TEMPS); + if (idx < TCG_MAX_TEMPS) { + /* There is already an available temp with the right type. */ + clear_bit(idx, s->free_temps[k].l); + ts = &s->temps[idx]; - s->first_free_temp[k] = ts->next_free_temp; ts->temp_allocated = 1; + assert(ts->base_type == type); assert(ts->temp_local == temp_local); } else { idx = s->nb_temps; @@ -568,7 +568,7 @@ TCGv_i64 tcg_temp_new_internal_i64(int temp_local) return MAKE_TCGV_I64(idx); } -static inline void tcg_temp_free_internal(int idx) +static void tcg_temp_free_internal(int idx) { TCGContext *s = &tcg_ctx; TCGTemp *ts; @@ -585,11 +585,9 @@ static inline void tcg_temp_free_internal(int idx) ts = &s->temps[idx]; assert(ts->temp_allocated != 0); ts->temp_allocated = 0; - k = ts->base_type; - if (ts->temp_local) - k += TCG_TYPE_COUNT; - ts->next_free_temp = s->first_free_temp[k]; - s->first_free_temp[k] = idx; + + k = ts->type + (ts->temp_local ? TCG_TYPE_COUNT : 0); + set_bit(idx, s->free_temps[k].l); } void tcg_temp_free_i32(TCGv_i32 arg) diff --git a/tcg/tcg.h b/tcg/tcg.h index 0d9bd293b5..c72af6cfb7 100644 --- a/tcg/tcg.h +++ b/tcg/tcg.h @@ -26,7 +26,7 @@ #define TCG_H #include "qemu-common.h" - +#include "qemu/bitops.h" #include "tcg-target.h" /* Default target word size to pointer size. */ @@ -436,13 +436,15 @@ typedef struct TCGTemp { basic blocks. Otherwise, it is not preserved across basic blocks. */ unsigned int temp_allocated:1; /* never used for code gen */ - /* index of next free temp of same base type, -1 if end */ - int next_free_temp; const char *name; } TCGTemp; typedef struct TCGContext TCGContext; +typedef struct TCGTempSet { + unsigned long l[BITS_TO_LONGS(TCG_MAX_TEMPS)]; +} TCGTempSet; + struct TCGContext { uint8_t *pool_cur, *pool_end; TCGPool *pool_first, *pool_current, *pool_first_large; @@ -450,8 +452,6 @@ struct TCGContext { int nb_labels; int nb_globals; int nb_temps; - /* index of free temps, -1 if none */ - int first_free_temp[TCG_TYPE_COUNT * 2]; /* goto_tb support */ uint8_t *code_buf; @@ -477,6 +477,7 @@ struct TCGContext { uint8_t *code_ptr; TCGTemp temps[TCG_MAX_TEMPS]; /* globals first, temps after */ + TCGTempSet free_temps[TCG_TYPE_COUNT * 2]; GHashTable *helpers; -- cgit v1.2.1