Optimize JDWP stack local values access

The StackFrame.GetValues and StackFrame.SetValues JDWP commands can refer to
multiple variables at the same time in a given frame. However we used to walk
the stack until getting to the requested frame for each variable.

Now, we walk the stack only once until getting to the frame so the context is
initialized. Then we read/write value for each variable from this context.

Bug: 17343501
Bug: 15680615

Change-Id: I2a4128f29a3c5856b994e280037c0a09eb48c5c8

1 files changed, 13 insertions, 4 deletions

diff --git a/runtime/debugger.h b/runtime/debugger.h
index 97985ec..cb7adae 100644
--- a/runtime/debugger.h
+++ b/runtime/debugger.h
@@ -45,6 +45,7 @@ class Throwable;
 class AllocRecord;
 class ObjectRegistry;
 class ScopedObjectAccessUnchecked;
+class StackVisitor;
 class Thread;
 class ThrowLocation;
 
@@ -475,12 +476,10 @@ class Dbg {
       LOCKS_EXCLUDED(Locks::thread_list_lock_,
                      Locks::thread_suspend_count_lock_)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
-  static JDWP::JdwpError GetLocalValue(JDWP::ObjectId thread_id, JDWP::FrameId frame_id, int slot,
-                                       JDWP::JdwpTag tag, uint8_t* buf, size_t expectedLen)
+  static JDWP::JdwpError GetLocalValues(JDWP::Request* request, JDWP::ExpandBuf* pReply)
       LOCKS_EXCLUDED(Locks::thread_list_lock_)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
-  static JDWP::JdwpError SetLocalValue(JDWP::ObjectId thread_id, JDWP::FrameId frame_id, int slot,
-                                       JDWP::JdwpTag tag, uint64_t value, size_t width)
+  static JDWP::JdwpError SetLocalValues(JDWP::Request* request)
       LOCKS_EXCLUDED(Locks::thread_list_lock_)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
@@ -641,6 +640,16 @@ class Dbg {
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
  private:
+  static JDWP::JdwpError GetLocalValue(const StackVisitor& visitor,
+                                       ScopedObjectAccessUnchecked& soa, int slot,
+                                       JDWP::JdwpTag tag, uint8_t* buf, size_t width)
+      LOCKS_EXCLUDED(Locks::thread_list_lock_)
+      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+  static JDWP::JdwpError SetLocalValue(StackVisitor& visitor, int slot, JDWP::JdwpTag tag,
+                                       uint64_t value, size_t width)
+      LOCKS_EXCLUDED(Locks::thread_list_lock_)
+      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+
   static void DdmBroadcast(bool connect) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
   static void PostThreadStartOrStop(Thread*, uint32_t)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);