commit 08fc03ae5dded4adc9b45b7014a4b9dfedbe95a6
author Elliott Hughes <enh@google.com> Tue Jun 26 17:34:00 2012 -0700
committer Elliott Hughes <enh@google.com> Wed Jun 27 12:18:25 2012 -0700
tree 3e767d037fd3e47e792b88d982ad38bce26d39e9
parent f94404ead1f2e4a1b5a2ff8bbdb65c5e4d4a77ea

Include held locks in SIGQUIT thread dumps.

Handy if you have an ANR that's locking related. Quick tour:

   at org.apache.harmony.dalvik.NativeTestTarget.emptyJniStaticSynchronizedMethod0(Native method)
   - locked <0x60135aa8> (a java.lang.Class<org.apache.harmony.dalvik.NativeTestTarget>)
   at java.lang.reflect.Method.invoke(Native method)
   at C.whileTrue(Main.java:63)
   at C.synchronizedOnClassString(Main.java:56)
   - locked <0x60002a70> (a java.lang.Class<java.lang.String>)
   at C.nestedSynchronizationWithTryCatch(Main.java:44)
   - locked <0x61336b90> (a java.lang.String)
   - locked <0x61336bd0> (a java.lang.String)
   at C.nestedSynchronization(Main.java:35)
   - locked <0x61336b18> (a java.lang.String)
   - locked <0x61336b50> (a java.lang.String)
   at C.synchronizedOnClassC(Main.java:30)
   - locked <0x613366f8> (a java.lang.Class<C>)
   at C.noLocks(Main.java:27)
   at C.<clinit>(Main.java:24)
   - locked <0x613366f8> (a java.lang.Class<C>)
   at Main.main(Main.java:19)

A non-static synchronized native method works too:

   at org.apache.harmony.dalvik.NativeTestTarget.emptyJniSynchronizedMethod0(Native method)
   - locked <0x613371a8> (a org.apache.harmony.dalvik.NativeTestTarget)
   ...

Note that most stack traces don't look any different; the above is a
pathological example that exercises different kinds of locking. Testing
with system_server shows most threads don't hold any locks.

Future work (marked by TODO) is that explicit JNI MonitorEnter calls in
native code aren't shown.

Change-Id: I2747f5cddb4ef64b1935736f084a68fe8e4005e9

src/native/dalvik_system_VMStack.cc

diff --git a/src/native/dalvik_system_VMStack.cc b/src/native/dalvik_system_VMStack.cc
index 933a5d5..12fa8db 100644
--- a/src/native/dalvik_system_VMStack.cc
+++ b/src/native/dalvik_system_VMStack.cc
@@ -56,8 +56,9 @@
     ClosestUserClassLoaderVisitor(const ManagedStack* stack,
                                   const std::vector<TraceStackFrame>* trace_stack,
                                   Object* bootstrap, Object* system)
-      : StackVisitor(stack, trace_stack), bootstrap(bootstrap), system(system),
-        class_loader(NULL) {}
+      : StackVisitor(stack, trace_stack, NULL),
+        bootstrap(bootstrap), system(system), class_loader(NULL) {}
+
     bool VisitFrame() {
       DCHECK(class_loader == NULL);
       Class* c = GetMethod()->GetDeclaringClass();
@@ -68,6 +69,7 @@
       }
       return true;
     }
+
     Object* bootstrap;
     Object* system;
     Object* class_loader;