[Qemu-devel] [PATCH v4 02/11] tcg-runtime: add lookup_tb_ptr helper

[Emilio G. Cota]

This paves the way for upcoming work.

Reviewed-by: Richard Henderson <r...@twiddle.net>
Reviewed-by: Alex Bennée <alex.ben...@linaro.org>
Signed-off-by: Emilio G. Cota <c...@braap.org>
---
 tcg-runtime.c     | 24 ++++++++++++++++++++++++
 tcg/tcg-runtime.h |  2 ++
 tcg/tcg.h         |  1 +
 3 files changed, 27 insertions(+)

diff --git a/tcg-runtime.c b/tcg-runtime.c
index 4c60c96..8a24bdd 100644
--- a/tcg-runtime.c
+++ b/tcg-runtime.c
@@ -27,6 +27,7 @@
 #include "exec/helper-proto.h"
 #include "exec/cpu_ldst.h"
 #include "exec/exec-all.h"
+#include "exec/tb-hash.h"
 
 /* 32-bit helpers */
 
@@ -141,6 +142,29 @@ uint64_t HELPER(ctpop_i64)(uint64_t arg)
     return ctpop64(arg);
 }
 
+void *HELPER(lookup_tb_ptr)(CPUArchState *env, target_ulong addr)
+{
+    CPUState *cpu = ENV_GET_CPU(env);
+    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)) {
+            return tb->tc_ptr;
+        }
+        tb = tb_htable_lookup(cpu, pc, cs_base, flags);
+        if (likely(tb)) {
+            atomic_set(&cpu->tb_jmp_cache[tb_jmp_cache_hash_func(addr)], tb);
+            return tb->tc_ptr;
+        }
+    }
+    return tcg_ctx.code_gen_epilogue;
+}
+
 void HELPER(exit_atomic)(CPUArchState *env)
 {
     cpu_loop_exit_atomic(ENV_GET_CPU(env), GETPC());
diff --git a/tcg/tcg-runtime.h b/tcg/tcg-runtime.h
index 114ea6f..c41d38a 100644
--- a/tcg/tcg-runtime.h
+++ b/tcg/tcg-runtime.h
@@ -24,6 +24,8 @@ DEF_HELPER_FLAGS_1(clrsb_i64, TCG_CALL_NO_RWG_SE, i64, i64)
 DEF_HELPER_FLAGS_1(ctpop_i32, TCG_CALL_NO_RWG_SE, i32, i32)
 DEF_HELPER_FLAGS_1(ctpop_i64, TCG_CALL_NO_RWG_SE, i64, i64)
 
+DEF_HELPER_FLAGS_2(lookup_tb_ptr, TCG_CALL_NO_WG_SE, ptr, env, tl)
+
 DEF_HELPER_FLAGS_1(exit_atomic, TCG_CALL_NO_WG, noreturn, env)
 
 #ifdef CONFIG_SOFTMMU
diff --git a/tcg/tcg.h b/tcg/tcg.h
index 6c216bb..5ec48d1 100644
--- a/tcg/tcg.h
+++ b/tcg/tcg.h
@@ -699,6 +699,7 @@ struct TCGContext {
        extension that allows arithmetic on void*.  */
     int code_gen_max_blocks;
     void *code_gen_prologue;
+    void *code_gen_epilogue;
     void *code_gen_buffer;
     size_t code_gen_buffer_size;
     void *code_gen_ptr;
-- 
2.7.4