Try to show lock owner in MONITOR thread dump.
A thread in the MONITOR state is blocked waiting on a monitor. This
raises two interesting questions: (1) what lock is it waiting on, and
(2) who holds that lock? The answer to (1) can be determined easily by
looking at the source code, but (2) is a bit harder.
This change extracts the target object from the instruction stream and
prints some information about it, e.g.:
- waiting to lock <0x40028c68> (a java.lang.Object) held by threadid=1 (main)
Also: fiddled with "must [not] be locked" on a recently-added function.
(cherry-picked from dalvik-dev)
Change-Id: Ic16695741760d50be70e70fb7470972cef28bb09
diff --git a/vm/Sync.c b/vm/Sync.c
index e6de6c3..fae35de 100644
--- a/vm/Sync.c
+++ b/vm/Sync.c
@@ -258,6 +258,21 @@
}
/*
+ * Get the thread that holds the lock on the specified object. The
+ * object may be unlocked, thin-locked, or fat-locked.
+ *
+ * The caller must lock the thread list before calling here.
+ */
+Thread* dvmGetObjectLockHolder(Object* obj)
+{
+ u4 threadId = lockOwner(obj);
+
+ if (threadId == 0)
+ return NULL;
+ return dvmGetThreadByThreadId(threadId);
+}
+
+/*
* Checks whether the given thread holds the given
* objects's lock.
*/