Richard Henderson <r...@twiddle.net> writes:
> Signed-off-by: Richard Henderson <r...@twiddle.net>
> ---
> target/alpha/translate.c | 49
> +++++++++++++++++++++++++++++++++++-------------
> 1 file changed, 36 insertions(+), 13 deletions(-)
>
> diff --git a/target/alpha/translate.c b/target/alpha/translate.c
> index df5d695..c1a5fbf 100644
> --- a/target/alpha/translate.c
> +++ b/target/alpha/translate.c
> @@ -89,6 +89,10 @@ typedef enum {
> updated the PC for the next instruction to be executed. */
> EXIT_PC_STALE,
>
> + /* Similarly, but force TB exit without chaining. */
> + EXIT_PC_UPDATED_FORCE,
> + EXIT_PC_STALE_FORCE,
> +
> /* We are ending the TB with a noreturn function call, e.g. longjmp.
> No following code will be executed. */
> EXIT_NORETURN,
> @@ -455,11 +459,16 @@ static bool in_superpage(DisasContext *ctx, int64_t
> addr)
> #endif
> }
>
> +static bool use_exit_tb(DisasContext *ctx)
> +{
> + /* Suppress any optimization in the case of single-steping and IO. */
> + return ((ctx->tb->cflags & CF_LAST_IO)
> + || ctx->singlestep_enabled || singlestep);
> +}
> +
> static bool use_goto_tb(DisasContext *ctx, uint64_t dest)
> {
> - /* Suppress goto_tb in the case of single-steping and IO. */
> - if ((ctx->tb->cflags & CF_LAST_IO)
> - || ctx->singlestep_enabled || singlestep) {
> + if (use_exit_tb(ctx)) {
> return false;
> }
> #ifndef CONFIG_USER_ONLY
> @@ -1257,14 +1266,14 @@ static ExitStatus gen_call_pal(DisasContext *ctx, int
> palcode)
> need the page permissions check. We'll see the existence of
> the page when we create the TB, and we'll flush all TBs if
> we change the PAL base register. */
> - if (!ctx->singlestep_enabled && !(ctx->tb->cflags & CF_LAST_IO)) {
> + if (use_exit_tb(ctx)) {
> + tcg_gen_movi_i64(cpu_pc, entry);
> + return EXIT_PC_UPDATED;
> + } else {
> tcg_gen_goto_tb(0);
> tcg_gen_movi_i64(cpu_pc, entry);
> tcg_gen_exit_tb((uintptr_t)ctx->tb);
> return EXIT_GOTO_TB;
> - } else {
> - tcg_gen_movi_i64(cpu_pc, entry);
> - return EXIT_PC_UPDATED;
> }
> }
> #endif
> @@ -1323,7 +1332,7 @@ static ExitStatus gen_mfpr(DisasContext *ctx, TCGv va,
> int regno)
> gen_io_start();
> helper(va);
> gen_io_end();
> - return EXIT_PC_STALE;
> + return EXIT_PC_STALE_FORCE;
> } else {
> helper(va);
> }
> @@ -1374,7 +1383,7 @@ static ExitStatus gen_mtpr(DisasContext *ctx, TCGv vb,
> int regno)
> case 252:
> /* HALT */
> gen_helper_halt(vb);
> - return EXIT_PC_STALE;
> + return EXIT_PC_STALE_FORCE;
>
> case 251:
> /* ALARM */
> @@ -1388,7 +1397,7 @@ static ExitStatus gen_mtpr(DisasContext *ctx, TCGv vb,
> int regno)
> that ended with a CALL_PAL. Since the base register usually only
> changes during boot, flushing everything works well. */
> gen_helper_tb_flush(cpu_env);
> - return EXIT_PC_STALE;
> + return EXIT_PC_STALE_FORCE;
>
> case 32 ... 39:
> /* Accessing the "non-shadow" general registers. */
> @@ -2373,7 +2382,7 @@ static ExitStatus translate_one(DisasContext *ctx,
> uint32_t insn)
> gen_io_start();
> gen_helper_load_pcc(va, cpu_env);
> gen_io_end();
> - ret = EXIT_PC_STALE;
> + ret = EXIT_PC_STALE_FORCE;
> } else {
> gen_helper_load_pcc(va, cpu_env);
> }
> @@ -2990,18 +2999,32 @@ void gen_intermediate_code(CPUAlphaState *env, struct
> TranslationBlock *tb)
> case EXIT_GOTO_TB:
> case EXIT_NORETURN:
> break;
> +
> case EXIT_PC_STALE:
> tcg_gen_movi_i64(cpu_pc, ctx.pc);
> - /* FALLTHRU */
> + goto do_exit_pc_updated;
> + case EXIT_PC_STALE_FORCE:
> + tcg_gen_movi_i64(cpu_pc, ctx.pc);
> + goto do_exit_pc_updated_force;
> +
> case EXIT_PC_UPDATED:
> + do_exit_pc_updated:
> + if (!use_exit_tb(&ctx)) {
> + tcg_gen_lookup_and_goto_ptr(cpu_pc);
> + break;
> + }
> + /* FALLTHRU */
> + case EXIT_PC_UPDATED_FORCE:
> + do_exit_pc_updated_force:
> if (ctx.singlestep_enabled) {
> gen_excp_1(EXCP_DEBUG, 0);
> } else {
> tcg_gen_exit_tb(0);
> }
> break;
Hmm this is ugly. You can make it a bit cleaner I think:
case EXIT_PC_STALE:
tcg_gen_movi_i64(cpu_pc, ctx.pc);
/* FALLTHRU */
case EXIT_PC_UPDATED:
if (!use_exit_tb(&ctx)) {
tcg_gen_lookup_and_goto_ptr(cpu_pc);
break;
}
goto do_exit_pc_updated_force;
case EXIT_PC_STALE_FORCE:
tcg_gen_movi_i64(cpu_pc, ctx.pc);
/* FALLTHRU */
case EXIT_PC_UPDATED_FORCE:
do_exit_pc_updated_force:
if (ctx.singlestep_enabled) {
gen_excp_1(EXCP_DEBUG, 0);
} else {
tcg_gen_exit_tb(0);
}
break;
But personally I'd be tempted to inline the force function and have:
static inline gen_exit_or_excp(void)
{
if (ctx.singlestep_enabled) {
gen_excp_1(EXCP_DEBUG, 0);
} else {
tcg_gen_exit_tb(0);
}
}
and:
case EXIT_PC_STALE:
tcg_gen_movi_i64(cpu_pc, ctx.pc);
/* FALLTHRU */
case EXIT_PC_UPDATED:
if (!use_exit_tb(&ctx)) {
tcg_gen_lookup_and_goto_ptr(cpu_pc);
break;
}
gen_exit_or_excp();
break;
case EXIT_PC_STALE_FORCE:
tcg_gen_movi_i64(cpu_pc, ctx.pc);
/* FALLTHRU */
case EXIT_PC_UPDATED_FORCE:
gen_exit_or_excp();
break;
default:
g_assert_not_reached();
}
> +
> default:
> - abort();
> + g_assert_not_reached();
> }
>
> gen_tb_end(tb, num_insns);
--
Alex Bennée
