From ab0c87bc6f3d752a33a37f666f13ac927ddb6014 Mon Sep 17 00:00:00 2001
From: Sergey Fedorov <serge.fdrv@gmail.com>
Date: Mon, 26 Feb 2018 02:05:14 -0500
Subject: [PATCH] tcg: Merge tb_find_slow() and tb_find_fast()

These functions are not too big and can be merged together. This makes
locking scheme more clear and easier to follow.

Backports commit bd2710d5da06ad7706d4864f65b3f0c9f7cb4d7f from qemu
---
 qemu/cpu-exec.c | 72 +++++++++++++++++++++----------------------------
 1 file changed, 30 insertions(+), 42 deletions(-)

diff --git a/qemu/cpu-exec.c b/qemu/cpu-exec.c
index c85fb3f2..204bb78e 100644
--- a/qemu/cpu-exec.c
+++ b/qemu/cpu-exec.c
@@ -137,46 +137,9 @@ static TranslationBlock *tb_find_physical(CPUState *cpu,
     return tb;
 }
 
-static TranslationBlock *tb_find_slow(CPUState *cpu,
-                                      target_ulong pc,
-                                      target_ulong cs_base,
-                                      uint32_t flags,
-                                      bool *have_tb_lock)
-{
-    TranslationBlock *tb;
-
-    tb = tb_find_physical(cpu, pc, cs_base, flags);
-    if (!tb) {
-        /* mmap_lock is needed by tb_gen_code, and mmap_lock must be
-         * taken outside tb_lock. As system emulation is currently
-         * single threaded the locks are NOPs.
-         */
-        mmap_lock();
-        // Unicorn: commented out
-        //tb_lock();
-        *have_tb_lock = true;
-
-        /* There's a chance that our desired tb has been translated while
-         * taking the locks so we check again inside the lock.
-         */
-        tb = tb_find_physical(cpu, pc, cs_base, flags);
-        if (!tb) {
-            /* if no translated code available, then translate it now */
-            tb = tb_gen_code(cpu, pc, cs_base, flags, 0);
-        }
-        // Unicorn: commented out
-        //tb_unlock();
-        mmap_unlock();
-    }
-
-    /* We add the TB in the virtual pc hash table for the fast lookup */
-    atomic_set(&cpu->tb_jmp_cache[tb_jmp_cache_hash_func(pc)], tb);
-    return tb;
-}
-
-static inline TranslationBlock *tb_find_fast(CPUState *cpu,
-                                             TranslationBlock *last_tb,
-                                             int tb_exit)
+static inline TranslationBlock *tb_find(CPUState *cpu,
+                                        TranslationBlock *last_tb,
+                                        int tb_exit)
 {
     CPUArchState *env = (CPUArchState *)cpu->env_ptr;
     TranslationBlock *tb;
@@ -192,7 +155,32 @@ static inline TranslationBlock *tb_find_fast(CPUState *cpu,
     tb = atomic_read(&cpu->tb_jmp_cache[tb_jmp_cache_hash_func(pc)]);
     if (unlikely(!tb || tb->pc != pc || tb->cs_base != cs_base ||
                 tb->flags != flags)) {
-        tb = tb_find_slow(cpu, pc, cs_base, flags, &have_tb_lock);
+        tb = tb_find_physical(cpu, pc, cs_base, flags);
+        if (!tb) {
+            /* mmap_lock is needed by tb_gen_code, and mmap_lock must be
+             * taken outside tb_lock. As system emulation is currently
+             * single threaded the locks are NOPs.
+             */
+            mmap_lock();
+            // Unicorn: commented out
+            //tb_lock();
+            have_tb_lock = true;
+
+            /* There's a chance that our desired tb has been translated while
+             * taking the locks so we check again inside the lock.
+             */
+            tb = tb_find_physical(cpu, pc, cs_base, flags);
+            if (!tb) {
+                /* if no translated code available, then translate it now */
+                tb = tb_gen_code(cpu, pc, cs_base, flags, 0);
+            }
+            // Unicorn: commented out
+            //tb_unlock();
+            mmap_unlock();
+        }
+
+        /* We add the TB in the virtual pc hash table for the fast lookup */
+        atomic_set(&cpu->tb_jmp_cache[tb_jmp_cache_hash_func(pc)], tb);
     }
 #ifndef CONFIG_USER_ONLY
     /* We don't take care of direct jumps when address mapping changes in
@@ -444,7 +432,7 @@ int cpu_exec(struct uc_struct *uc, CPUState *cpu)
             atomic_mb_set(&cpu->tb_flushed, false); /* reset before first TB lookup */
             for(;;) {
                 cpu_handle_interrupt(cpu, &last_tb);
-                tb = tb_find_fast(cpu, last_tb, tb_exit);
+                tb = tb_find(cpu, last_tb, tb_exit);
                 if (!tb) {   // invalid TB due to invalid code?
                     uc->invalid_error = UC_ERR_FETCH_UNMAPPED;
                     ret = EXCP_HLT;