8262486: Merge trivial JDWP agent changes from the loom repo to the j…

…dk repo

Reviewed-by: amenkov, lmesnik

src/jdk.jdwp.agent/share/native/libjdwp/eventFilter.c

@@ -518,8 +518,7 @@ eventFilterRestricted_passesFilter(JNIEnv *env,
 
           case JDWP_REQUEST_MODIFIER(SourceNameMatch): {
               char* desiredNamePattern = filter->u.SourceNameOnly.sourceNamePattern;
-              if (searchAllSourceNames(env, clazz,
-                           desiredNamePattern) != 1) {
+              if (searchAllSourceNames(env, clazz, desiredNamePattern) != 1) {
                   /* The name isn't in the SDE; try the sourceName in the ref
                    * type
                    */
@@ -943,7 +942,6 @@ eventFilter_setStepFilter(HandlerNode *node, jint index,
     return JVMTI_ERROR_NONE;
 }
 
-
 jvmtiError
 eventFilter_setSourceNameMatchFilter(HandlerNode *node,
                                     jint index,

src/jdk.jdwp.agent/share/native/libjdwp/eventHandler.c

@@ -269,7 +269,7 @@ eventHandlerRestricted_iterator(EventIndex ei,
 
 /* BREAKPOINT, METHOD_ENTRY and SINGLE_STEP events are covered by
  * the co-location of events policy. Of these three co-located
- * events, METHOD_ENTRY is  always reported first and BREAKPOINT
+ * events, METHOD_ENTRY is always reported first and BREAKPOINT
  * is always reported last. Here are the possible combinations and
  * their order:
  *
@@ -534,7 +534,8 @@ synthesizeUnloadEvent(void *signatureVoid, void *envVoid)
 /* Garbage Collection Happened */
 static unsigned int garbageCollected = 0;
 
-/* The JVMTI generic event callback. Each event is passed to a sequence of
+/*
+ * The JVMTI generic event callback. Each event is passed to a sequence of
  * handlers in a chain until the chain ends or one handler
  * consumes the event.
  */
@@ -545,8 +546,9 @@ event_callback(JNIEnv *env, EventInfo *evinfo)
     jbyte eventSessionID = currentSessionID; /* session could change */
     jthrowable currentException;
     jthread thread;
+    EventIndex ei = evinfo->ei;
 
-    LOG_MISC(("event_callback(): ei=%s", eventText(evinfo->ei)));
+    LOG_MISC(("event_callback(): ei=%s", eventText(ei)));
     log_debugee_location("event_callback()", evinfo->thread, evinfo->method, evinfo->location);
 
     /* We want to preserve any current exception that might get
@@ -602,8 +604,7 @@ event_callback(JNIEnv *env, EventInfo *evinfo)
          * resources can be allocated.  This must be done before
          * grabbing any locks.
          */
-        eventBag = threadControl_onEventHandlerEntry(eventSessionID,
-                                 evinfo->ei, thread, currentException);
+        eventBag = threadControl_onEventHandlerEntry(eventSessionID, evinfo, currentException);
         if ( eventBag == NULL ) {
             jboolean invoking;
             do {

src/jdk.jdwp.agent/share/native/libjdwp/eventHelper.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2021, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -1045,12 +1045,12 @@ eventHelper_reportEvents(jbyte sessionID, struct bag *eventBag)
 
 void
 eventHelper_recordEvent(EventInfo *evinfo, jint id, jbyte suspendPolicy,
-                         struct bag *eventBag)
+                        struct bag *eventBag)
 {
     JNIEnv *env = getEnv();
     CommandSingle *command = bagAdd(eventBag);
     if (command == NULL) {
-        EXIT_ERROR(AGENT_ERROR_OUT_OF_MEMORY,"badAdd(eventBag)");
+        EXIT_ERROR(AGENT_ERROR_OUT_OF_MEMORY,"bagAdd(eventBag)");
     }
 
     command->singleKind = COMMAND_SINGLE_EVENT;

src/jdk.jdwp.agent/share/native/libjdwp/standardHandlers.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001, 2005, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2021, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -36,6 +36,7 @@
 
 #include "standardHandlers.h"
 
+/* HandlerFunction - Invoked from event_callback() */
 static void
 handleClassPrepare(JNIEnv *env, EventInfo *evinfo,
                    HandlerNode *node,
@@ -75,6 +76,7 @@ handleClassPrepare(JNIEnv *env, EventInfo *evinfo,
                             node->suspendPolicy, eventBag);
 }
 
+/* HandlerFunction - Invoked from event_callback() */
 static void
 handleGarbageCollectionFinish(JNIEnv *env, EventInfo *evinfo,
                   HandlerNode *node,
@@ -83,6 +85,7 @@ handleGarbageCollectionFinish(JNIEnv *env, EventInfo *evinfo,
     JDI_ASSERT_MSG(JNI_FALSE, "Should never call handleGarbageCollectionFinish");
 }
 
+/* HandlerFunction - Invoked from event_callback() for METHOD_ENTRY and METHOD_EXIT. */
 static void
 handleFrameEvent(JNIEnv *env, EventInfo *evinfo,
                  HandlerNode *node,
@@ -122,6 +125,7 @@ handleFrameEvent(JNIEnv *env, EventInfo *evinfo,
                                  eventBag);
 }
 
+/* HandlerFunction - Invoked from event_callback() */
 static void
 genericHandler(JNIEnv *env, EventInfo *evinfo,
                HandlerNode *node,

src/jdk.jdwp.agent/share/native/libjdwp/stepControl.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998, 2005, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2021, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -341,18 +341,21 @@ handleFramePopEvent(JNIEnv *env, EventInfo *evinfo,
              */
             LOG_STEP(("handleFramePopEvent: starting singlestep, depth==OUT && fromDepth > afterPopDepth (%d>%d)",fromDepth, afterPopDepth));
             enableStepping(thread);
-        } else if (step->methodEnterHandlerNode != NULL &&
-                   fromDepth >= afterPopDepth) {
-            /*
-             * We installed a method entry event handler as part of a
-             * step into operation. We've popped back to the original
-             * stepping frame without finding a place to stop.
-             * Resume stepping in the original frame.
-             */
-            LOG_STEP(("handleFramePopEvent: starting singlestep, have methodEnter handler && depth==OUT && fromDepth >= afterPopDepth (%d>%d)",fromDepth, afterPopDepth));
-            enableStepping(thread);
-            (void)eventHandler_free(step->methodEnterHandlerNode);
-            step->methodEnterHandlerNode = NULL;
+        } else if (step->methodEnterHandlerNode != NULL) {
+            /* We installed a method entry event handler as part of a step into operation. */
+            JDI_ASSERT(step->depth == JDWP_STEP_DEPTH(INTO));
+            if (fromDepth >= afterPopDepth) {
+                /*
+                 * We've popped back to the original stepping frame without finding a place to stop.
+                 * Resume stepping in the original frame.
+                 */
+                LOG_STEP(("handleFramePopEvent: starting singlestep, have methodEnter handler && depth==INTO && fromDepth >= afterPopDepth (%d>=%d)", fromDepth, afterPopDepth));
+                enableStepping(thread);
+                (void)eventHandler_free(step->methodEnterHandlerNode);
+                step->methodEnterHandlerNode = NULL;
+            } else {
+                LOG_STEP(("handleFramePopEvent: starting singlestep, have methodEnter handler && depth==INTO && fromDepth < afterPopDepth (%d<%d)", fromDepth, afterPopDepth));
+            }
         }
         LOG_STEP(("handleFramePopEvent: finished"));
     }
@@ -603,6 +606,8 @@ stepControl_handleStep(JNIEnv *env, jthread thread,
                                 "installing event method enter handler");
                 }
             }
+            LOG_STEP(("stepControl_handleStep: NotifyFramePop (fromDepth=%d currentDepth=%d)",
+                      fromDepth, currentDepth));
 
             error = JVMTI_FUNC_PTR(gdata->jvmti,NotifyFramePop)
                         (gdata->jvmti, thread, 0);
@@ -739,6 +744,7 @@ initEvents(jthread thread, StepRequest *step)
                                      EI_EXCEPTION_CATCH,
                                      handleExceptionCatchEvent,
                                      thread);
+        JDI_ASSERT(step->framePopHandlerNode == NULL);
         step->framePopHandlerNode = eventHandler_createInternalThreadOnly(
                                         EI_FRAME_POP,
                                         handleFramePopEvent,
@@ -793,7 +799,7 @@ stepControl_beginStep(JNIEnv *env, jthread thread, jint size, jint depth,
     jvmtiError error2;
 
     LOG_STEP(("stepControl_beginStep: thread=%p,size=%d,depth=%d",
-                        thread, size, depth));
+              thread, size, depth));
 
     eventHandler_lock(); /* for proper lock order */
     stepControl_lock();

src/jdk.jdwp.agent/share/native/libjdwp/threadControl.c

@@ -39,6 +39,8 @@
  * If the ei field is non-zero, then one of the possible
  * co-located events has been posted and the other fields describe
  * the event's location.
+ *
+ * See comment above deferEventReport() for an explanation of co-located events.
  */
 typedef struct CoLocatedEventInfo_ {
     EventIndex ei;
@@ -63,27 +65,28 @@ typedef struct CoLocatedEventInfo_ {
  */
 typedef struct ThreadNode {
     jthread thread;
-    unsigned int toBeResumed : 1;
-    unsigned int pendingInterrupt : 1;
-    unsigned int isDebugThread : 1;
-    unsigned int suspendOnStart : 1;
-    unsigned int isStarted : 1;
+    unsigned int toBeResumed : 1;      /* true if this thread was successfully suspended. */
+    unsigned int pendingInterrupt : 1; /* true if thread is interrupted while handling an event. */
+    unsigned int isDebugThread : 1;    /* true if this is one of our debug agent threads. */
+    unsigned int suspendOnStart : 1;   /* true for new threads if we are currently in a VM.suspend(). */
+    unsigned int isStarted : 1;        /* THREAD_START or VIRTUAL_THREAD_SCHEDULED event received. */
     unsigned int popFrameEvent : 1;
     unsigned int popFrameProceed : 1;
     unsigned int popFrameThread : 1;
-    EventIndex current_ei;
-    jobject pendingStop;
+    EventIndex current_ei; /* Used to determine if we are currently handling an event on this thread. */
+    jobject pendingStop;   /* Object we are throwing to stop the thread (ThreadReferenceImpl.stop). */
     jint suspendCount;
     jint resumeFrameDepth; /* !=0 => This thread is in a call to Thread.resume() */
     jvmtiEventMode instructionStepMode;
     StepRequest currentStep;
     InvokeRequest currentInvoke;
-    struct bag *eventBag;
-    CoLocatedEventInfo cleInfo;
+    struct bag *eventBag;       /* Accumulation of JDWP events to be sent as a reply. */
+    CoLocatedEventInfo cleInfo; /* See comment above deferEventReport() for an explanation. */
     struct ThreadNode *next;
     struct ThreadNode *prev;
-    jlong frameGeneration;
-    struct ThreadList *list;  /* Tells us what list this thread is in */
+    jlong frameGeneration;    /* used to generate a unique frameID. Incremented whenever existing frameID
+                                 needs to be invalidated, such as when the thread is resumed. */
+    struct ThreadList *list;  /* Tells us what list this thread is in. */
 #ifdef DEBUG_THREADNAME
     char name[256];
 #endif
@@ -228,7 +231,10 @@ nonTlsSearch(JNIEnv *env, ThreadList *list, jthread thread)
 /*
  * These functions maintain the linked list of currently running threads.
  * All assume that the threadLock is held before calling.
- * If list==NULL, search both lists.
+ */
+
+/*
+ * Search for a thread on the list. If list==NULL, search all lists.
  */
 static ThreadNode *
 findThread(ThreadList *list, jthread thread)
@@ -672,6 +678,10 @@ notifyAppResumeComplete(void)
     }
 }
 
+/*
+ * Event handler for FRAME_POP and EXCEPTION_CATCH when in Thread.resume()
+ * so we can detect its completion.
+ */
 static void
 handleAppResumeCompletion(JNIEnv *env, EventInfo *evinfo,
                           HandlerNode *handlerNode,
@@ -756,6 +766,7 @@ trackAppResume(jthread thread)
     }
 }
 
+/* Global breakpoint handler for Thread.resume() */
 static void
 handleAppResumeBreakpoint(JNIEnv *env, EventInfo *evinfo,
                           HandlerNode *handlerNode,
@@ -927,7 +938,7 @@ deferredSuspendThreadByNode(ThreadNode *node)
          * happens when suspendOnStart is set to true.
          */
         if (error != JVMTI_ERROR_NONE) {
-          node->suspendCount--;
+            node->suspendCount--;
         }
     }
 
@@ -1080,6 +1091,9 @@ commonSuspend(JNIEnv *env, jthread thread, jboolean deferred)
      * to a separate list of threads so that we'll resume it later.
      */
     node = findThread(&runningThreads, thread);
+#if 0
+    tty_message("commonSuspend: node(%p) suspendCount(%d) %s", node, node->suspendCount, node->name);
+#endif
     if (node == NULL) {
         node = insertThread(env, &otherThreads, thread);
     }
@@ -1387,7 +1401,6 @@ commonSuspendList(JNIEnv *env, jint initCount, jthread *initList)
     return error;
 }
 
-
 static jvmtiError
 commonResume(jthread thread)
 {
@@ -1399,6 +1412,9 @@ commonResume(jthread thread)
      * not, check the auxiliary list used by threadControl_suspendThread.
      */
     node = findThread(NULL, thread);
+#if 0
+    tty_message("commonResume: node(%p) suspendCount(%d) %s", node, node->suspendCount, node->name);
+#endif
 
     /*
      * If the node is in neither list, the debugger never suspended
@@ -1520,6 +1536,9 @@ threadControl_suspendAll(void)
 {
     jvmtiError error;
     JNIEnv    *env;
+#if 0
+    tty_message("threadControl_suspendAll: suspendAllCount(%d)", suspendAllCount);
+#endif
 
     env = getEnv();
 
@@ -1593,6 +1612,9 @@ threadControl_resumeAll(void)
 {
     jvmtiError error;
     JNIEnv    *env;
+#if 0
+    tty_message("threadControl_resumeAll: suspendAllCount(%d)", suspendAllCount);
+#endif
 
     env = getEnv();
 
@@ -2050,13 +2072,15 @@ checkForPopFrameEvents(JNIEnv *env, EventIndex ei, jthread thread)
 }
 
 struct bag *
-threadControl_onEventHandlerEntry(jbyte sessionID, EventIndex ei, jthread thread, jobject currentException)
+threadControl_onEventHandlerEntry(jbyte sessionID, EventInfo *evinfo, jobject currentException)
 {
     ThreadNode *node;
     JNIEnv     *env;
     struct bag *eventBag;
     jthread     threadToSuspend;
     jboolean    consumed;
+    EventIndex  ei = evinfo->ei;
+    jthread     thread = evinfo->thread;
 
     env             = getEnv();
     threadToSuspend = NULL;
@@ -2483,7 +2507,8 @@ threadControl_setEventMode(jvmtiEventMode mode, EventIndex ei, jthread thread)
  * Returns the current thread, if the thread has generated at least
  * one event, and has not generated a thread end event.
  */
-jthread threadControl_currentThread(void)
+jthread
+threadControl_currentThread(void)
 {
     jthread thread;
 

src/jdk.jdwp.agent/share/native/libjdwp/threadControl.h

@@ -40,8 +40,7 @@ void threadControl_onDisconnect(void);
 
 jvmtiError threadControl_popFrames(jthread thread, FrameNumber fnum);
 
-struct bag *threadControl_onEventHandlerEntry(jbyte sessionID,
-                  EventIndex ei, jthread thread, jobject currentException);
+struct bag *threadControl_onEventHandlerEntry(jbyte sessionID, EventInfo *evinfo, jobject currentException);
 void threadControl_onEventHandlerExit(EventIndex ei, jthread thread, struct bag *);