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[Qemu-devel] [PATCH v2 1/5] tcg: Refactor helper_lookup_tb_ptr
From: |
Richard Henderson |
Subject: |
[Qemu-devel] [PATCH v2 1/5] tcg: Refactor helper_lookup_tb_ptr |
Date: |
Wed, 14 Jun 2017 12:48:17 -0700 |
We can call tb_htable_lookup even when the tb_jmp_cache
is completely empty. Therefore, un-nest most of the code
dependent on tb != NULL from the read from the cache.
Signed-off-by: Richard Henderson <address@hidden>
---
tcg-runtime.c | 34 ++++++++++++++++++----------------
1 file changed, 18 insertions(+), 16 deletions(-)
diff --git a/tcg-runtime.c b/tcg-runtime.c
index 7fa90ce..a35c725 100644
--- a/tcg-runtime.c
+++ b/tcg-runtime.c
@@ -147,30 +147,32 @@ uint64_t HELPER(ctpop_i64)(uint64_t arg)
void *HELPER(lookup_tb_ptr)(CPUArchState *env, target_ulong addr)
{
CPUState *cpu = ENV_GET_CPU(env);
+ void *ret = tcg_ctx.code_gen_epilogue;
TranslationBlock *tb;
target_ulong cs_base, pc;
- uint32_t flags;
-
- tb = atomic_rcu_read(&cpu->tb_jmp_cache[tb_jmp_cache_hash_func(addr)]);
- if (likely(tb)) {
- cpu_get_tb_cpu_state(env, &pc, &cs_base, &flags);
- if (likely(tb->pc == addr && tb->cs_base == cs_base &&
- tb->flags == flags)) {
- goto found;
- }
+ uint32_t flags, addr_hash;
+
+ addr_hash = tb_jmp_cache_hash_func(addr);
+ tb = atomic_rcu_read(&cpu->tb_jmp_cache[addr_hash]);
+ cpu_get_tb_cpu_state(env, &pc, &cs_base, &flags);
+
+ if (unlikely(!(tb
+ && tb->pc == addr
+ && tb->cs_base == cs_base
+ && tb->flags == flags))) {
tb = tb_htable_lookup(cpu, addr, cs_base, flags);
- if (likely(tb)) {
- atomic_set(&cpu->tb_jmp_cache[tb_jmp_cache_hash_func(addr)], tb);
- goto found;
+ if (!tb) {
+ return ret;
}
+ atomic_set(&cpu->tb_jmp_cache[addr_hash], tb);
}
- return tcg_ctx.code_gen_epilogue;
- found:
+
+ ret = tb->tc_ptr;
qemu_log_mask_and_addr(CPU_LOG_EXEC, addr,
"Chain %p [%d: " TARGET_FMT_lx "] %s\n",
- tb->tc_ptr, cpu->cpu_index, addr,
+ ret, cpu->cpu_index, addr,
lookup_symbol(addr));
- return tb->tc_ptr;
+ return ret;
}
void HELPER(exit_atomic)(CPUArchState *env)
--
2.9.4