[Qemu-devel] [PATCH] cpu-exec: make TBs generated codes unlinked when -singlestep

[Jincheng Miao <jmiao@redhat.com>]

'-singlestep' option will make TB contains only one instruction,
so that the qemu_log could output trace log when CPU_LOG_EXEC sets,
and it could help developers to debug control flow.

But currently, in cpu_exec(), it doesn't check singlestep when
tb_add_jump(), so the TB linked is executed siliently.
Therefore, this patch adds singlestep check before tb_add_jump().

Signed-off-by: Jincheng Miao <jmiao@redhat.com>
---
 cpu-exec.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/cpu-exec.c b/cpu-exec.c
index 38e5f02..64b7289 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -622,8 +622,8 @@ int cpu_exec(CPUArchState *env)
                 }
                 /* see if we can patch the calling TB. When the TB
                    spans two pages, we cannot safely do a direct
-                   jump. */
-                if (next_tb != 0 && tb->page_addr[1] == -1) {
+                   jump. So as when singlestep is enabled. */
+                if (next_tb != 0 && tb->page_addr[1] == -1 && !singlestep) {
                     tb_add_jump((TranslationBlock *)(next_tb & ~TB_EXIT_MASK),
                                 next_tb & TB_EXIT_MASK, tb);
                 }
-- 
1.7.1