3 files changed, 15 insertions, 1 deletions
diff --git a/runtime/jdwp/jdwp_event.cc b/runtime/jdwp/jdwp_event.cc
index 6908047..adc1074 100644
--- a/runtime/jdwp/jdwp_event.cc
+++ b/runtime/jdwp/jdwp_event.cc
@@ -233,7 +233,16 @@ void JdwpState::UnregisterEvent(JdwpEvent* pEvent) {
       Dbg::UnconfigureStep(pMod->step.threadId);
     }
   }
-  if (NeedsFullDeoptimization(pEvent->eventKind)) {
+  if (pEvent->eventKind == EK_SINGLE_STEP) {
+    // Special case for single-steps where we want to avoid the slow pattern deoptimize/undeoptimize
+    // loop between each single-step. In a IDE, this would happens each time the user click on the
+    // "single-step" button. Here we delay the full undeoptimization to the next resume
+    // (VM.Resume or ThreadReference.Resume) or the end of the debugging session (VM.Dispose or
+    // runtime shutdown).
+    // Therefore, in a singles-stepping sequence, only the first single-step will trigger a full
+    // deoptimization and only the last single-step will trigger a full undeoptimization.
+    Dbg::DelayFullUndeoptimization();
+  } else if (NeedsFullDeoptimization(pEvent->eventKind)) {
     CHECK_EQ(req.kind, DeoptimizationRequest::kNothing);
     CHECK(req.method == nullptr);
     req.kind = DeoptimizationRequest::kFullUndeoptimization;
diff --git a/runtime/jdwp/jdwp_handler.cc b/runtime/jdwp/jdwp_handler.cc
index 5ffe753..8ef375b 100644
--- a/runtime/jdwp/jdwp_handler.cc
+++ b/runtime/jdwp/jdwp_handler.cc
@@ -291,6 +291,7 @@ static JdwpError VM_Suspend(JdwpState*, Request&, ExpandBuf*)
  */
 static JdwpError VM_Resume(JdwpState*, Request&, ExpandBuf*)
     SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+  Dbg::ProcessDelayedFullUndeoptimizations();
   Dbg::ResumeVM();
   return ERR_NONE;
 }
@@ -980,6 +981,8 @@ static JdwpError TR_Resume(JdwpState*, Request& request, ExpandBuf*)
     return ERR_NONE;
   }
 
+  Dbg::ProcessDelayedFullUndeoptimizations();
+
   Dbg::ResumeThread(thread_id);
   return ERR_NONE;
 }
diff --git a/runtime/jdwp/jdwp_main.cc b/runtime/jdwp/jdwp_main.cc
index 8e22c1d..f480256 100644
--- a/runtime/jdwp/jdwp_main.cc
+++ b/runtime/jdwp/jdwp_main.cc
@@ -318,6 +318,8 @@ void JdwpState::ResetState() {
     CHECK(event_list_ == NULL);
   }
 
+  Dbg::ProcessDelayedFullUndeoptimizations();
+
   /*
    * Should not have one of these in progress.  If the debugger went away
    * mid-request, though, we could see this.