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Speeding up Truffle debugging #9142

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9e24c44
Commenting out this line speeds Truffle debugger 10 times
jtulach Jan 14, 2026
6268481
Observe an invocation of to com.oracle.truffle.polyglot.PolyglotImpl.…
jtulach Jan 16, 2026
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48 changes: 29 additions & 19 deletions ...gger.jpda.truffle/src/org/netbeans/modules/debugger/jpda/truffle/TruffleDebugManager.java
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Original file line number Diff line number Diff line change
Expand Up @@ -59,43 +59,50 @@
*/
@DebuggerServiceRegistration(types=LazyDebuggerManagerListener.class)
public class TruffleDebugManager extends DebuggerManagerAdapter {

private static final Logger LOG = Logger.getLogger(TruffleDebugManager.class.getName());

private static final String ENGINE_CLASS = "org.graalvm.polyglot.Engine"; // NOI18N
private static final String ENGINE_BUILDER_CLASS = "org.graalvm.polyglot.Engine$Builder"; // NOI18N
private static final String POLY_IMPL_CLASS = "com.oracle.truffle.polyglot.PolyglotImpl"; // NOI18N
private static final String POLY_IMPL_BUILD_METHOD = "buildEngine"; // NOI18N
private static final String REMOTE_SERVICES_TRIGGER_CLASS = "com.oracle.truffle.api.Truffle"; // NOI18N
private static final String REMOTE_SERVICES_TRIGGER_METHOD = "getRuntime"; // NOI18N
// Breakpoint on this class triggers search of existing engines
private static final String EXISTING_ENGINES_TRIGGER = "com.oracle.truffle.api.frame.Frame"; // NOI18N
private JPDABreakpoint debugManagerLoadBP;

private MethodBreakpoint debugManagerLoadBP;
private Map<JPDADebugger, JPDABreakpoint> initServiceBPs = new HashMap<>();
private static final Map<JPDADebugger, Boolean> haveExistingEnginesTrigger = new WeakHashMap<>();
private static final Map<JPDADebugger, DebugManagerHandler> dmHandlers = new HashMap<>();
private static final Map<JPDADebugger, JPDABreakpointListener> debugBPListeners = new HashMap<>();

public TruffleDebugManager() {
}

@Override
public Breakpoint[] initBreakpoints() {
initLoadBP();
return new Breakpoint[] { debugManagerLoadBP };
}

private synchronized void initLoadBP() {
if (debugManagerLoadBP != null) {
return ;
}
/* Must NOT use a method exit breakpoint! It caused a massive degradation of application performance.
debugManagerLoadBP = MethodBreakpoint.create(SESSION_CREATION_BP_CLASS, SESSION_CREATION_BP_METHOD);
((MethodBreakpoint) debugManagerLoadBP).setBreakpointType(MethodBreakpoint.TYPE_METHOD_EXIT);
/*
- Must NOT use a method exit breakpoint!
- It caused a massive degradation of application performance.
- we will attach an exit breakpoint, but the later the better
- we need a method that's called the "latest" before returning
- from `Engine.Builder.build()`
- as of GraalVM 25.0.1 it is:
- [this one](https://github.com/oracle/graal/blob/05ec02567a77a30cc41b8ad9174de0dc5737ceaf/sdk/src/org.graalvm.polyglot/src/org/graalvm/polyglot/Engine.java#L843)
*/
debugManagerLoadBP = MethodBreakpoint.create(ENGINE_BUILDER_CLASS, "build");
((MethodBreakpoint) debugManagerLoadBP).setBreakpointType(MethodBreakpoint.TYPE_METHOD_ENTRY);
debugManagerLoadBP = MethodBreakpoint.create(POLY_IMPL_CLASS, POLY_IMPL_BUILD_METHOD);
debugManagerLoadBP.setBreakpointType(MethodBreakpoint.TYPE_METHOD_ENTRY);
debugManagerLoadBP.setHidden(true);

LOG.log(Level.FINE, "TruffleDebugManager.initBreakpoints(): submitted BP {0}", debugManagerLoadBP);
TruffleAccess.init();
}
Expand Down Expand Up @@ -182,7 +189,8 @@ private JPDABreakpointListener addPolyglotEngineCreationBP(final JPDADebugger de
public void breakpointReached(JPDABreakpointEvent event) {
try {
if (event.getDebugger() == debugger) {
handleEngineBuilder(debugger, event);
LOG.log(Level.FINE, "Building of an Engine is in progress");
handleJustBuiltEngine(debugger, event.getThread());
}
} finally {
event.resume();
Expand Down Expand Up @@ -225,18 +233,20 @@ public void propertyChange(PropertyChangeEvent evt) {
* We need to submit a temporary method-exit breakpoint on the build method.
* We must not keep the method exit breakpoint active as it causes a significant performance degradation.
*/
private void handleEngineBuilder(final JPDADebugger debugger, JPDABreakpointEvent entryEvent) {
private void handleJustBuiltEngine(final JPDADebugger debugger, JPDAThread onThread) {
MethodBreakpoint builderExitBreakpoint = MethodBreakpoint.create(ENGINE_BUILDER_CLASS, "build");
builderExitBreakpoint.setBreakpointType(MethodBreakpoint.TYPE_METHOD_EXIT);
builderExitBreakpoint.setThreadFilters(debugger, new JPDAThread[]{entryEvent.getThread()});
builderExitBreakpoint.setThreadFilters(debugger, new JPDAThread[]{onThread});
builderExitBreakpoint.setSuspend(JPDABreakpoint.SUSPEND_EVENT_THREAD);
builderExitBreakpoint.setSession(debugger);
builderExitBreakpoint.setHidden(true);
builderExitBreakpoint.addJPDABreakpointListener(exitEvent -> {
try {
builderExitBreakpoint.disable();
DebuggerManager.getDebuggerManager().removeBreakpoint(builderExitBreakpoint);
haveNewPE(debugger, (JPDAThreadImpl) exitEvent.getThread(), (ObjectReference) ((JDIVariable) exitEvent.getVariable()).getJDIValue());
final ObjectReference ref = (ObjectReference) ((JDIVariable) exitEvent.getVariable()).getJDIValue();
LOG.log(Level.FINE, "New Engine has just been built: {0}", ref);
haveNewPE(debugger, (JPDAThreadImpl) exitEvent.getThread(), ref);
} finally {
exitEvent.resume();
}
Expand Down Expand Up @@ -326,7 +336,7 @@ public void breakpointRemoved(Breakpoint breakpoint) {
}
}
}

public static ClassType getDebugAccessorClass(JPDADebugger debugger) {
synchronized (dmHandlers) {
DebugManagerHandler dmh = dmHandlers.get(debugger);
Expand All @@ -337,7 +347,7 @@ public static ClassType getDebugAccessorClass(JPDADebugger debugger) {
}
}
}

public static JPDAClassType getDebugAccessorJPDAClass(JPDADebugger debugger) {
synchronized (dmHandlers) {
DebugManagerHandler dmh = dmHandlers.get(debugger);
Expand Down
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