tcg: Use uintptr_t type for jmp_list_{next|first} fields of TB

These fields do not contain pure pointers to a TranslationBlock
structure. So uintptr_t is the most appropriate type for them.
Also put some asserts to assure that the two least significant bits of
the pointer are always zero before assigning it to jmp_list_first.

Signed-off-by: Sergey Fedorov <serge.fdrv@gmail.com>
Signed-off-by: Sergey Fedorov <sergey.fedorov@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>

1 files changed, 7 insertions, 5 deletions

diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h
index 445d946d84..64c2a660bc 100644
--- a/include/exec/exec-all.h
+++ b/include/exec/exec-all.h
@@ -277,14 +277,16 @@ struct TranslationBlock {
      * jmp_list_first points to the first TB jumping to this one.
      * jmp_list_next is used to point to the next TB in a list.
      * Since each TB can have two jumps, it can participate in two lists.
-     * The two least significant bits of a pointer are used to choose which
-     * data field holds a pointer to the next TB:
+     * jmp_list_first and jmp_list_next are 4-byte aligned pointers to a
+     * TranslationBlock structure, but the two least significant bits of
+     * them are used to encode which data field of the pointed TB should
+     * be used to traverse the list further from that TB:
      * 0 => jmp_list_next[0], 1 => jmp_list_next[1], 2 => jmp_list_first.
      * In other words, 0/1 tells which jump is used in the pointed TB,
      * and 2 means that this is a pointer back to the target TB of this list.
      */
-    struct TranslationBlock *jmp_list_next[2];
-    struct TranslationBlock *jmp_list_first;
+    uintptr_t jmp_list_next[2];
+    uintptr_t jmp_list_first;
 };
 
 #include "qemu/thread.h"
@@ -382,7 +384,7 @@ static inline void tb_add_jump(TranslationBlock *tb, int n,
 
         /* add in TB jmp circular list */
         tb->jmp_list_next[n] = tb_next->jmp_list_first;
-        tb_next->jmp_list_first = (TranslationBlock *)((uintptr_t)tb | n);
+        tb_next->jmp_list_first = (uintptr_t)tb | n;
     }
 }