JDWP: Optimized single step during debugging
For single stepping full deoptimization and undeoptimizations were
performed with significant overhead, because every code will be
executed in interpreted mode during a single step, even if it is not
strictly required.
For example, if we have a computation heavy method call and we would
like to step over it, that method (and all the methods called from it)
will run in interpreter mode. This can take so long in some cases
(e.g. multiple minutes) that it makes debugging process unusable.
The solution for this limitation is not using full deoptimizations for
single steps and force interpreter only for those methods that we are
about to step into, and require stack deoptimization before step outs.
Bug: 17750566
Bug: 18094282
Bug: https://code.google.com/p/android/issues/detail?id=77984
Change-Id: I683c52465883146c4c84ec47bf96f8efd920527f
Signed-off-by: Daniel Mihalyi <daniel.mihalyi@mattakis.com>
diff --git a/runtime/debugger.h b/runtime/debugger.h
index 01c9d5d..d015294 100644
--- a/runtime/debugger.h
+++ b/runtime/debugger.h
@@ -243,7 +243,9 @@
// Returns true if we're actually debugging with a real debugger, false if it's
// just DDMS (or nothing at all).
- static bool IsDebuggerActive();
+ static bool IsDebuggerActive() {
+ return gDebuggerActive;
+ }
// Configures JDWP with parsed command-line options.
static void ConfigureJdwp(const JDWP::JdwpOptions& jdwp_options);
@@ -543,13 +545,6 @@
LOCKS_EXCLUDED(Locks::deoptimization_lock_)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
- // Support delayed full undeoptimization requests. This is currently only used for single-step
- // events.
- static void DelayFullUndeoptimization() LOCKS_EXCLUDED(Locks::deoptimization_lock_);
- static void ProcessDelayedFullUndeoptimizations()
- LOCKS_EXCLUDED(Locks::deoptimization_lock_)
- SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
-
// Manage deoptimization after updating JDWP events list. Suspends all threads, processes each
// request and finally resumes all threads.
static void ManageDeoptimization()
@@ -564,6 +559,53 @@
LOCKS_EXCLUDED(Locks::breakpoint_lock_)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+ /*
+ * Forced interpreter checkers for single-step and continue support.
+ */
+
+ // Indicates whether we need to force the use of interpreter to invoke a method.
+ // This allows to single-step or continue into the called method.
+ static bool IsForcedInterpreterNeededForCalling(Thread* thread, mirror::ArtMethod* m)
+ SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+ if (!IsDebuggerActive()) {
+ return false;
+ }
+ return IsForcedInterpreterNeededForCallingImpl(thread, m);
+ }
+
+ // Indicates whether we need to force the use of interpreter entrypoint when calling a
+ // method through the resolution trampoline. This allows to single-step or continue into
+ // the called method.
+ static bool IsForcedInterpreterNeededForResolution(Thread* thread, mirror::ArtMethod* m)
+ SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+ if (!IsDebuggerActive()) {
+ return false;
+ }
+ return IsForcedInterpreterNeededForResolutionImpl(thread, m);
+ }
+
+ // Indicates whether we need to force the use of instrumentation entrypoint when calling
+ // a method through the resolution trampoline. This allows to deoptimize the stack for
+ // debugging when we returned from the called method.
+ static bool IsForcedInstrumentationNeededForResolution(Thread* thread, mirror::ArtMethod* m)
+ SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+ if (!IsDebuggerActive()) {
+ return false;
+ }
+ return IsForcedInstrumentationNeededForResolutionImpl(thread, m);
+ }
+
+ // Indicates whether we need to force the use of interpreter when returning from the
+ // interpreter into the runtime. This allows to deoptimize the stack and continue
+ // execution with interpreter for debugging.
+ static bool IsForcedInterpreterNeededForUpcall(Thread* thread, mirror::ArtMethod* m)
+ SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+ if (!IsDebuggerActive()) {
+ return false;
+ }
+ return IsForcedInterpreterNeededForUpcallImpl(thread, m);
+ }
+
// Single-stepping.
static JDWP::JdwpError ConfigureStep(JDWP::ObjectId thread_id, JDWP::JdwpStepSize size,
JDWP::JdwpStepDepth depth)
@@ -690,11 +732,27 @@
EXCLUSIVE_LOCKS_REQUIRED(Locks::deoptimization_lock_)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+ static bool IsForcedInterpreterNeededForCallingImpl(Thread* thread, mirror::ArtMethod* m)
+ SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+
+ static bool IsForcedInterpreterNeededForResolutionImpl(Thread* thread, mirror::ArtMethod* m)
+ SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+
+ static bool IsForcedInstrumentationNeededForResolutionImpl(Thread* thread, mirror::ArtMethod* m)
+ SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+
+ static bool IsForcedInterpreterNeededForUpcallImpl(Thread* thread, mirror::ArtMethod* m)
+ SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+
static AllocRecord* recent_allocation_records_ PT_GUARDED_BY(Locks::alloc_tracker_lock_);
static size_t alloc_record_max_ GUARDED_BY(Locks::alloc_tracker_lock_);
static size_t alloc_record_head_ GUARDED_BY(Locks::alloc_tracker_lock_);
static size_t alloc_record_count_ GUARDED_BY(Locks::alloc_tracker_lock_);
+ // Indicates whether the debugger is making requests.
+ static bool gDebuggerActive;
+
+ // The registry mapping objects to JDWP ids.
static ObjectRegistry* gRegistry;
// Deoptimization requests to be processed each time the event list is updated. This is used when
@@ -709,10 +767,6 @@
// undeoptimize when the last event is unregistered (when the counter is set to 0).
static size_t full_deoptimization_event_count_ GUARDED_BY(Locks::deoptimization_lock_);
- // Count the number of full undeoptimization requests delayed to next resume or end of debug
- // session.
- static size_t delayed_full_undeoptimization_count_ GUARDED_BY(Locks::deoptimization_lock_);
-
static size_t* GetReferenceCounterForEvent(uint32_t instrumentation_event);
// Weak global type cache, TODO improve this.