[Qemu-devel] [PATCH v2 08/13] target/arm: optimize cross-page block chaining in softmmu

["Emilio G. Cota" <cota@braap.org>]

Instead of unconditionally exiting to the exec loop, use the
lookup_tb_ptr helper to jump to the target if it is valid.
As long as the hit rate in tb_jmp_cache remains high, this
will improve performance.

Perf impact: see the next commit's log.

Signed-off-by: Emilio G. Cota <cota@braap.org>
---
 target/arm/translate.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/target/arm/translate.c b/target/arm/translate.c
index e32e38c..574cf70 100644
--- a/target/arm/translate.c
+++ b/target/arm/translate.c
@@ -4085,8 +4085,12 @@ static inline void gen_goto_tb(DisasContext *s, int n, target_ulong dest)
         gen_set_pc_im(s, dest);
         tcg_gen_exit_tb((uintptr_t)s->tb + n);
     } else {
+        TCGv_ptr ptr = tcg_temp_new_ptr();
+
         gen_set_pc_im(s, dest);
-        tcg_gen_exit_tb(0);
+        gen_helper_lookup_tb_ptr(ptr, cpu_env, cpu_R[15]);
+        tcg_gen_goto_ptr(ptr);
+        tcg_temp_free_ptr(ptr);
     }
 }
 
-- 
2.7.4