fixed for bug# 151253 -Single steping a mult-thread program to fast results in unexpected behavior

debug/org.eclipse.cdt.debug.mi.core/cdi/org/eclipse/cdt/debug/mi/core/cdi/ExpressionManager.java

@@ -184,9 +184,10 @@ public class ExpressionManager extends Manager {
 		Target target = (Target)frame.getTarget();
 		Thread currentThread = (Thread)target.getCurrentThread();
 		StackFrame currentFrame = currentThread.getCurrentStackFrame();
-		target.setCurrentThread(frame.getThread(), false);
+		target.lockTarget();
-		((Thread)frame.getThread()).setCurrentStackFrame(frame, false);
 		try {
+			target.setCurrentThread(frame.getThread(), false);
+			((Thread)frame.getThread()).setCurrentStackFrame(frame, false);
 			MISession mi = target.getMISession();
 			CommandFactory factory = mi.getCommandFactory();
 			MIVarCreate var = factory.createMIVarCreate(code);
@@ -204,6 +205,7 @@ public class ExpressionManager extends Manager {
 		} finally {
 			target.setCurrentThread(currentThread, false);
 			currentThread.setCurrentStackFrame(currentFrame, false);
+			target.releaseTarget();
 		}
 	}
 

debug/org.eclipse.cdt.debug.mi.core/cdi/org/eclipse/cdt/debug/mi/core/cdi/RegisterManager.java

@@ -254,9 +254,10 @@ public class RegisterManager extends Manager {
 		Target target = (Target)frame.getTarget();
 		Thread currentThread = (Thread)target.getCurrentThread();
 		StackFrame currentFrame = currentThread.getCurrentStackFrame();
-		target.setCurrentThread(frame.getThread(), false);
+		target.lockTarget();
-		((Thread)frame.getThread()).setCurrentStackFrame(frame, false);
 		try {
+			target.setCurrentThread(frame.getThread(), false);
+			((Thread)frame.getThread()).setCurrentStackFrame(frame, false);
 			MISession mi = target.getMISession();
 			CommandFactory factory = mi.getCommandFactory();
 			MIVarCreate var = factory.createMIVarCreate(regName);
@@ -269,8 +270,12 @@ public class RegisterManager extends Manager {
 		} catch (MIException e) {
 			throw new MI2CDIException(e);
 		} finally {
+			try {
 			target.setCurrentThread(currentThread, false);
 			currentThread.setCurrentStackFrame(currentFrame, false);
+			} finally {
+				target.releaseTarget();
+			}
 		}
 	}
 

debug/org.eclipse.cdt.debug.mi.core/cdi/org/eclipse/cdt/debug/mi/core/cdi/SourceManager.java

@@ -424,13 +424,15 @@ public class SourceManager extends Manager {
 		Target target = (Target)frame.getTarget();
 		Thread currentThread = (Thread)target.getCurrentThread();
 		StackFrame currentFrame = currentThread.getCurrentStackFrame();
-		target.setCurrentThread(frame.getThread(), false);
+		target.lockTarget();
-		((Thread)frame.getThread()).setCurrentStackFrame(frame, false);
 		try {
+			target.setCurrentThread(frame.getThread(), false);
+			((Thread)frame.getThread()).setCurrentStackFrame(frame, false);
 			return getDetailTypeName(target, variable);
 		} finally {
 			target.setCurrentThread(currentThread, false);
 			currentThread.setCurrentStackFrame(currentFrame, false);
+			target.releaseTarget();
 		}
 	}
 	public String getDetailTypeName(Target target, String typename) throws CDIException {
@@ -460,13 +462,15 @@ public class SourceManager extends Manager {
 		Target target = (Target)frame.getTarget();
 		Thread currentThread = (Thread)target.getCurrentThread();
 		StackFrame currentFrame = currentThread.getCurrentStackFrame();
-		target.setCurrentThread(frame.getThread(), false);
+		target.lockTarget();
-		((Thread)frame.getThread()).setCurrentStackFrame(frame, false);
 		try {
+			target.setCurrentThread(frame.getThread(), false);
+			((Thread)frame.getThread()).setCurrentStackFrame(frame, false);
 			return getTypeName(target, variable);
 		} finally {
 			target.setCurrentThread(currentThread, false);
 			currentThread.setCurrentStackFrame(currentFrame, false);
+			target.releaseTarget();
 		}
 	}
 

debug/org.eclipse.cdt.debug.mi.core/cdi/org/eclipse/cdt/debug/mi/core/cdi/VariableManager.java

@@ -175,9 +175,10 @@ public class VariableManager extends Manager {
 			Target target = (Target)frame.getTarget();
 			Thread currentThread = (Thread)target.getCurrentThread();
 			StackFrame currentFrame = currentThread.getCurrentStackFrame();
-			target.setCurrentThread(frame.getThread(), false);
+			target.lockTarget();
-			((Thread)frame.getThread()).setCurrentStackFrame(frame, false);
 			try {
+				target.setCurrentThread(frame.getThread(), false);
+				((Thread)frame.getThread()).setCurrentStackFrame(frame, false);
 				MISession miSession = target.getMISession();
 				RxThread rxThread = miSession.getRxThread();
 				rxThread.setEnableConsole(false);
@@ -196,6 +197,7 @@ public class VariableManager extends Manager {
 				rxThread.setEnableConsole(true);
 				target.setCurrentThread(currentThread, false);
 				currentThread.setCurrentStackFrame(currentFrame, false);
+				target.releaseTarget();
 			}
 		} else {
 			throw new CDIException(CdiResources.getString("cdi.VariableManager.Unknown_type")); //$NON-NLS-1$
@@ -367,9 +369,10 @@ public class VariableManager extends Manager {
 			Target target = (Target)argDesc.getTarget();
 			Thread currentThread = (Thread)target.getCurrentThread();
 			StackFrame currentFrame = currentThread.getCurrentStackFrame();
-			target.setCurrentThread(stack.getThread(), false);
+			target.lockTarget();
-			((Thread)stack.getThread()).setCurrentStackFrame(stack, false);
 			try {
+				target.setCurrentThread(stack.getThread(), false);
+				((Thread)stack.getThread()).setCurrentStackFrame(stack, false);
 				MISession mi = target.getMISession();
 				CommandFactory factory = mi.getCommandFactory();
 				MIVarCreate var = factory.createMIVarCreate(name);
@@ -388,6 +391,7 @@ public class VariableManager extends Manager {
 			} finally {
 				target.setCurrentThread(currentThread, false);
 				currentThread.setCurrentStackFrame(currentFrame, false);
+				target.releaseTarget();
 			}
 		}
 		return argument;
@@ -398,9 +402,10 @@ public class VariableManager extends Manager {
 		Target target = (Target)frame.getTarget();
 		Thread currentThread = (Thread)target.getCurrentThread();
 		StackFrame currentFrame = currentThread.getCurrentStackFrame();
-		target.setCurrentThread(frame.getThread(), false);
+		target.lockTarget();
-		((Thread)frame.getThread()).setCurrentStackFrame(frame, false);
 		try {
+			target.setCurrentThread(frame.getThread(), false);
+			((Thread)frame.getThread()).setCurrentStackFrame(frame, false);
 			MISession mi = target.getMISession();
 			CommandFactory factory = mi.getCommandFactory();
 			int depth = frame.getThread().getStackFrameCount();
@@ -429,6 +434,7 @@ public class VariableManager extends Manager {
 		} finally {
 			target.setCurrentThread(currentThread, false);
 			currentThread.setCurrentStackFrame(currentFrame, false);
+			target.releaseTarget();
 		}
 		return (ICDIArgumentDescriptor[]) argObjects.toArray(new ICDIArgumentDescriptor[0]);
 	}
@@ -489,9 +495,10 @@ public class VariableManager extends Manager {
 		Target target = (Target)frame.getTarget();
 		Thread currentThread = (Thread)target.getCurrentThread();
 		StackFrame currentFrame = currentThread.getCurrentStackFrame();
-		target.setCurrentThread(frame.getThread(), false);
+		target.lockTarget();
-		((Thread)frame.getThread()).setCurrentStackFrame(frame, false);
 		try {
+			target.setCurrentThread(frame.getThread(), false);
+			((Thread)frame.getThread()).setCurrentStackFrame(frame, false);
 			MISession mi = target.getMISession();
 			CommandFactory factory = mi.getCommandFactory();
 			int level = frame.getLevel();
@@ -514,6 +521,7 @@ public class VariableManager extends Manager {
 		} finally {
 			target.setCurrentThread(currentThread, false);
 			currentThread.setCurrentStackFrame(currentFrame, false);
+			target.releaseTarget();
 		}
 		return (ICDILocalVariableDescriptor[]) varObjects.toArray(new ICDILocalVariableDescriptor[0]);
 	}
@@ -530,9 +538,10 @@ public class VariableManager extends Manager {
 			Target target = (Target)varDesc.getTarget();
 			Thread currentThread = (Thread)target.getCurrentThread();
 			StackFrame currentFrame = currentThread.getCurrentStackFrame();
-			target.setCurrentThread(stack.getThread(), false);
+			target.lockTarget();
-			((Thread)stack.getThread()).setCurrentStackFrame(stack, false);
 			try {
+				target.setCurrentThread(stack.getThread(), false);
+				((Thread)stack.getThread()).setCurrentStackFrame(stack, false);
 				MISession mi = target.getMISession();
 				CommandFactory factory = mi.getCommandFactory();
 				MIVarCreate var = factory.createMIVarCreate(name);
@@ -551,6 +560,7 @@ public class VariableManager extends Manager {
 			} finally {
 				target.setCurrentThread(currentThread, false);
 				currentThread.setCurrentStackFrame(currentFrame, false);
+				target.releaseTarget();
 			}
 		}
 		return local;

debug/org.eclipse.cdt.debug.mi.core/cdi/org/eclipse/cdt/debug/mi/core/cdi/model/Target.java

@@ -13,6 +13,7 @@ package org.eclipse.cdt.debug.mi.core.cdi.model;
 import java.math.BigInteger;
 import java.util.ArrayList;
 import java.util.List;
+
 import org.eclipse.cdt.debug.core.cdi.CDIException;
 import org.eclipse.cdt.debug.core.cdi.ICDIAddressLocation;
 import org.eclipse.cdt.debug.core.cdi.ICDICondition;
@@ -87,6 +88,45 @@ import org.eclipse.cdt.debug.mi.core.output.MIThreadSelectInfo;
  */
 public class Target extends SessionObject implements ICDITarget {
 
+	public class Lock {
+
+		java.lang.Thread heldBy;
+		int count;
+
+		public Lock() {
+
+		}
+
+		public synchronized void aquire() {
+			if (heldBy == null || heldBy == java.lang.Thread.currentThread()) {
+				heldBy = java.lang.Thread.currentThread();
+				count++;
+			} else {
+				while (true) {
+					try {
+						wait();
+					} catch (InterruptedException e) {
+					}
+					if (heldBy == null) {
+						heldBy = java.lang.Thread.currentThread();
+						count++;
+						return;
+					}					
+				}
+			}
+		}
+
+		public synchronized void release() {
+			if (heldBy == null || heldBy != java.lang.Thread.currentThread()) {
+				throw new IllegalStateException("Thread does not own lock");
+			}
+			if(--count == 0) {
+				heldBy = null;
+				notifyAll();
+			}
+		}
+	}
+
 	MISession miSession;
 	ICDITargetConfiguration fConfiguration;
 	Thread[] noThreads = new Thread[0];
@@ -95,13 +135,22 @@ public class Target extends SessionObject implements ICDITarget {
 	String fEndian = null;
 	boolean suspended = true;
 	boolean deferBreakpoints = true;
-	
+	Lock lock = new Lock();
+
 	public Target(Session s, MISession mi) {
 		super(s);
 		miSession = mi;
 		currentThreads = noThreads;
 	}
 
+	public void lockTarget() {
+		lock.aquire();
+	}
+	
+	public void releaseTarget() {
+		lock.release();
+	}
+	
 	public MISession getMISession() {
 		return miSession;
 	}
@@ -116,7 +165,7 @@ public class Target extends SessionObject implements ICDITarget {
 	public ICDITarget getTarget() {
 		return this;
 	}
-	
+
 	/**
 	 * @see org.eclipse.cdt.debug.core.cdi.model.ICDITarget#setCurrentThread(ICDIThread)
 	 */
@@ -127,7 +176,7 @@ public class Target extends SessionObject implements ICDITarget {
 			throw new CDIException(CdiResources.getString("cdi.model.Target.Unknown_thread")); //$NON-NLS-1$
 		}
 	}
-	
+
 	public void setCurrentThread(ICDIThread cthread, boolean doUpdate) throws CDIException {
 		if (cthread instanceof Thread) {
 			setCurrentThread((Thread)cthread, doUpdate);
@@ -163,7 +212,7 @@ public class Target extends SessionObject implements ICDITarget {
 				currentThreadId = info.getNewThreadId();
 
 				// @^&#@^$*^$
-				// GDB reset the currentFrame to  some other level 0 when switching thread.
+				// GDB reset the currentFrame to some other level 0 when switching thread.
 				// we need to reposition the current stack level.
 				MIFrame miFrame = info.getFrame();
 				if (miFrame != null) {
@@ -176,7 +225,7 @@ public class Target extends SessionObject implements ICDITarget {
 
 			Session session = (Session)getSession();
 			// Resetting threads may change the value of
-			// some variables like Register.  Call an update()
+			// some variables like Register. Call an update()
 			// To generate changeEvents.
 			if (doUpdate) {
 				RegisterManager regMgr = session.getRegisterManager();
@@ -192,7 +241,7 @@ public class Target extends SessionObject implements ICDITarget {
 
 		// We should be allright now.
 		if (currentThreadId != id) {
-			// thread is gone.  Generate a Thread destroyed.
+			// thread is gone. Generate a Thread destroyed.
 			miSession.fireEvent(new MIThreadExitEvent(miSession, id));
 			throw new CDIException(CdiResources.getString("cdi.model.Target.Cannot_switch_to_thread") + id); //$NON-NLS-1$
 		}
@@ -205,7 +254,7 @@ public class Target extends SessionObject implements ICDITarget {
 		Thread[] oldThreads = currentThreads;
 
 		// If we use "info threads" in getCThreads() this
-		// will be overwritten.  However if we use -stack-list-threads
+		// will be overwritten. However if we use -stack-list-threads
 		// it does not provide to the current thread
 		currentThreadId = newThreadId;
 
@@ -280,11 +329,11 @@ public class Target extends SessionObject implements ICDITarget {
 			// HACK/FIXME: gdb/mi thread-list-ids does not
 			// show any newly create thread, we workaround by
 			// issuing "info threads" instead.
-			//MIThreadListIds tids = factory.createMIThreadListIds();
+			// MIThreadListIds tids = factory.createMIThreadListIds();
-			//MIThreadListIdsInfo info = tids.getMIThreadListIdsInfo();
+			// MIThreadListIdsInfo info = tids.getMIThreadListIdsInfo();
 			miSession.postCommand(tids);
 			CLIInfoThreadsInfo info = tids.getMIInfoThreadsInfo();
-			int [] ids;
+			int[] ids;
 			String[] names;
 			if (info == null) {
 				ids = new int[0];
@@ -310,7 +359,7 @@ public class Target extends SessionObject implements ICDITarget {
 				cthreads = new Thread[]{new Thread(this, 0)};
 			}
 			currentThreadId = info.getCurrentThread();
-			//FIX: When attaching there is no thread selected
+			// FIX: When attaching there is no thread selected
 			// We will choose the first one as a workaround.
 			if (currentThreadId == 0 && cthreads.length > 0) {
 				currentThreadId = cthreads[0].getId();
@@ -416,10 +465,9 @@ public class Target extends SessionObject implements ICDITarget {
 			}
 		} catch (MIException e) {
 			throw new MI2CDIException(e);
-		}		
+		}
 	}
 
-
 	/**
 	 * @see org.eclipse.cdt.debug.core.cdi.model.ICDITarget#stepIntoInstruction()
 	 */
@@ -442,7 +490,7 @@ public class Target extends SessionObject implements ICDITarget {
 		} catch (MIException e) {
 			throw new MI2CDIException(e);
 		}
-		
+
 	}
 
 	/**
@@ -466,7 +514,7 @@ public class Target extends SessionObject implements ICDITarget {
 			}
 		} catch (MIException e) {
 			throw new MI2CDIException(e);
-		}		
+		}
 	}
 
 	/**
@@ -529,14 +577,14 @@ public class Target extends SessionObject implements ICDITarget {
 				}
 			}
 		} else if (location instanceof ICDIAddressLocation) {
-			ICDIAddressLocation addrLocation = (ICDIAddressLocation) location;
+			ICDIAddressLocation addrLocation = (ICDIAddressLocation)location;
-			if (! addrLocation.getAddress().equals(BigInteger.ZERO)) {
+			if (!addrLocation.getAddress().equals(BigInteger.ZERO)) {
 				loc = "*0x" + addrLocation.getAddress().toString(16); //$NON-NLS-1$
 			}
 		}
 		// Throw an exception we do know where to go
 		if (loc == null) {
-			throw new CDIException (CdiResources.getString("cdi.mode.Target.Bad_location")); //$NON-NLS-1$
+			throw new CDIException(CdiResources.getString("cdi.mode.Target.Bad_location")); //$NON-NLS-1$
 		}
 		MIExecUntil until = factory.createMIExecUntil(loc);
 		try {
@@ -547,7 +595,7 @@ public class Target extends SessionObject implements ICDITarget {
 			}
 		} catch (MIException e) {
 			throw new MI2CDIException(e);
-		}		
+		}
 	}
 
 	/**
@@ -580,7 +628,7 @@ public class Target extends SessionObject implements ICDITarget {
 				((EventManager)getSession().getEventManager()).allowProcessingEvents(false);
 				suspend();
 			} finally {
-				((EventManager)getSession().getEventManager()).allowProcessingEvents(true);			
+				((EventManager)getSession().getEventManager()).allowProcessingEvents(true);
 			}
 		}
 		CommandFactory factory = miSession.getCommandFactory();
@@ -651,7 +699,7 @@ public class Target extends SessionObject implements ICDITarget {
 			}
 		} catch (MIException e) {
 			throw new MI2CDIException(e);
-		}		
+		}
 	}
 
 	/**
@@ -676,14 +724,14 @@ public class Target extends SessionObject implements ICDITarget {
 				}
 			}
 		} else if (location instanceof ICDIAddressLocation) {
-			ICDIAddressLocation addrLocation = (ICDIAddressLocation) location;
+			ICDIAddressLocation addrLocation = (ICDIAddressLocation)location;
-			if (! addrLocation.getAddress().equals(BigInteger.ZERO)) {
+			if (!addrLocation.getAddress().equals(BigInteger.ZERO)) {
 				loc = "*0x" + addrLocation.getAddress().toString(16); //$NON-NLS-1$
 			}
 		}
 		// Throw an exception we do know where to go
 		if (loc == null) {
-			throw new CDIException (CdiResources.getString("cdi.mode.Target.Bad_location")); //$NON-NLS-1$
+			throw new CDIException(CdiResources.getString("cdi.mode.Target.Bad_location")); //$NON-NLS-1$
 		}
 
 		CLIJump jump = factory.createCLIJump(loc);
@@ -871,10 +919,10 @@ public class Target extends SessionObject implements ICDITarget {
 	 */
 	public void deleteAllBreakpoints() throws CDIException {
 		BreakpointManager bMgr = ((Session)getSession()).getBreakpointManager();
-		bMgr.deleteAllBreakpoints(this);		
+		bMgr.deleteAllBreakpoints(this);
 	}
 
-	/* 
+	/*
 	 * @see org.eclipse.cdt.debug.core.cdi.model.ICDITarget#createCondition(int, java.lang.String, String)
 	 */
 	public ICDICondition createCondition(int ignoreCount, String expression) {
@@ -1090,14 +1138,14 @@ public class Target extends SessionObject implements ICDITarget {
 		if (fConfiguration == null) {
 			if (miSession.isProgramSession()) {
 				fConfiguration = new TargetConfiguration(this);
-			}  else if (miSession.isAttachSession()){
+			} else if (miSession.isAttachSession()) {
 				fConfiguration = new TargetConfiguration(this);
 			} else if (miSession.isCoreSession()) {
 				fConfiguration = new CoreFileConfiguration(this);
 			} else {
-				fConfiguration = new TargetConfiguration(this);				
+				fConfiguration = new TargetConfiguration(this);
 			}
-		}		
+		}
 		return fConfiguration;
 	}
 
@@ -1119,12 +1167,12 @@ public class Target extends SessionObject implements ICDITarget {
 		if (varDesc instanceof RegisterDescriptor) {
 			Session session = (Session)getTarget().getSession();
 			RegisterManager mgr = session.getRegisterManager();
-			return mgr.createRegister((RegisterDescriptor)varDesc);			
+			return mgr.createRegister((RegisterDescriptor)varDesc);
 		}
-		return null;		
+		return null;
 	}
 
-	public void deferBreakpoints( boolean defer ) {
+	public void deferBreakpoints(boolean defer) {
 		this.deferBreakpoints = defer;
 	}
 

debug/org.eclipse.cdt.debug.mi.core/cdi/org/eclipse/cdt/debug/mi/core/cdi/model/Thread.java

@@ -109,8 +109,9 @@ public class Thread extends CObject implements ICDIThread {
 			currentFrames = new ArrayList();
 			Target target = (Target)getTarget();
 			ICDIThread currentThread = target.getCurrentThread();
-			target.setCurrentThread(this, false);
+			target.lockTarget();
 			try {
+				target.setCurrentThread(this, false);
 				MISession mi = target.getMISession();
 				CommandFactory factory = mi.getCommandFactory();
 				MIStackListFrames frames = factory.createMIStackListFrames();
@@ -131,6 +132,7 @@ public class Thread extends CObject implements ICDIThread {
 				//System.out.println(e);
 			} finally {
 				target.setCurrentThread(currentThread, false);
+				target.releaseTarget();
 			}
 			// assign the currentFrame if it was not done yet.
 			if (currentFrame == null) {
@@ -152,8 +154,9 @@ public class Thread extends CObject implements ICDIThread {
 		if (stackdepth == 0) {
 			Target target = (Target)getTarget();
 			ICDIThread currentThread = target.getCurrentThread();
-			target.setCurrentThread(this, false);
+			target.lockTarget();
 			try {
+				target.setCurrentThread(this, false);
 				MISession mi = target.getMISession();
 				CommandFactory factory = mi.getCommandFactory();
 				MIStackInfoDepth depth = factory.createMIStackInfoDepth();
@@ -184,6 +187,7 @@ public class Thread extends CObject implements ICDIThread {
 				throw new MI2CDIException(e);
 			} finally {
 				target.setCurrentThread(currentThread, false);
+				target.releaseTarget();
 			}
 		}
 		return stackdepth;
@@ -197,8 +201,9 @@ public class Thread extends CObject implements ICDIThread {
 			currentFrames = new ArrayList();
 			Target target = (Target) getTarget();
 			ICDIThread currentThread = target.getCurrentThread();
-			target.setCurrentThread(this, false);
+			target.lockTarget();
 			try {
+				target.setCurrentThread(this, false);
 				int depth = getStackFrameCount();
 				int upperBound;
 				// try to get the largest subset.
@@ -230,6 +235,7 @@ public class Thread extends CObject implements ICDIThread {
 				//System.out.println(e);
 			} finally {
 				target.setCurrentThread(currentThread, false);
+				target.releaseTarget();
 			}
 			// take time to assign the currentFrame, if it is in the set
 			if (currentFrame == null) {
@@ -268,7 +274,6 @@ public class Thread extends CObject implements ICDIThread {
 			}
 		}
 
-		try {
 			Target target = (Target)getTarget();
 			MISession mi = target.getMISession();
 			CommandFactory factory = mi.getCommandFactory();
@@ -277,29 +282,33 @@ public class Thread extends CObject implements ICDIThread {
 			int miLevel = getStackFrameCount() - frameLevel;
 			MIStackSelectFrame frame = factory.createMIStackSelectFrame(miLevel);
 			// Set ourself as the current thread first.
-			target.setCurrentThread(this, doUpdate);
+			target.lockTarget();
-			mi.postCommand(frame);
+			try {
-			MIInfo info = frame.getMIInfo();
+				target.setCurrentThread(this, doUpdate);
-			if (info == null) {
+				mi.postCommand(frame);
-				throw new CDIException(CdiResources.getString("cdi.Common.No_answer")); //$NON-NLS-1$
+				MIInfo info = frame.getMIInfo();
-			}
+				if (info == null) {
-			currentFrame = stackframe;
+					throw new CDIException(CdiResources.getString("cdi.Common.No_answer")); //$NON-NLS-1$
-			// Resetting stackframe may change the value of
-			// some variables like registers. Call an update()
-			// To generate changeEvents.
-			if (doUpdate) {
-				Session session = (Session) target.getSession();
-				RegisterManager regMgr = session.getRegisterManager();
-				if (regMgr.isAutoUpdate()) {
-					regMgr.update(target);
 				}
-				VariableManager varMgr = session.getVariableManager();
+				currentFrame = stackframe;
-				if (varMgr.isAutoUpdate()) {
+				// Resetting stackframe may change the value of
-					varMgr.update(target);
+				// some variables like registers. Call an update()
+				// To generate changeEvents.
+				if (doUpdate) {
+					Session session = (Session) target.getSession();
+					RegisterManager regMgr = session.getRegisterManager();
+					if (regMgr.isAutoUpdate()) {
+						regMgr.update(target);
+					}
+					VariableManager varMgr = session.getVariableManager();
+					if (varMgr.isAutoUpdate()) {
+						varMgr.update(target);
+					}
 				}
-			}
 		} catch (MIException e) {
 			throw new MI2CDIException(e);
+		} finally {
+			target.releaseTarget();
 		}
 	}
 
@@ -314,8 +323,13 @@ public class Thread extends CObject implements ICDIThread {
 	 * @see org.eclipse.cdt.debug.core.cdi.model.ICDIExecuteStep#stepInto(int)
 	 */
 	public void stepInto(int count) throws CDIException {
-		((Target)getTarget()).setCurrentThread(this);
+		((Target)getTarget()).lockTarget();
-		getTarget().stepInto(count);
+		try {
+			((Target)getTarget()).setCurrentThread(this);
+			getTarget().stepInto(count);
+		} finally {
+			((Target)getTarget()).releaseTarget();			
+		}
 	}
 
 	/**
@@ -329,8 +343,13 @@ public class Thread extends CObject implements ICDIThread {
 	 * @see org.eclipse.cdt.debug.core.cdi.model.ICDIExecuteStep#stepIntoInstruction(int)
 	 */
 	public void stepIntoInstruction(int count) throws CDIException {
-		((Target)getTarget()).setCurrentThread(this);
+		((Target)getTarget()).lockTarget();
-		getTarget().stepIntoInstruction(count);
+		try {
+			((Target)getTarget()).setCurrentThread(this);
+			getTarget().stepIntoInstruction(count);
+		} finally {
+			((Target)getTarget()).releaseTarget();			
+		}
 	}
 
 	/**
@@ -344,9 +363,13 @@ public class Thread extends CObject implements ICDIThread {
 	 * @see org.eclipse.cdt.debug.core.cdi.model.ICDIExecuteStep#stepOver(int)
 	 */
 	public void stepOver(int count) throws CDIException {
-		((Target)getTarget()).setCurrentThread(this);
+		((Target)getTarget()).lockTarget();
-		getTarget().stepOver(count);
+		try {
-		
+			((Target)getTarget()).setCurrentThread(this);
+			getTarget().stepOver(count);
+		} finally {
+			((Target)getTarget()).releaseTarget();			
+		}
 	}
 
 	/**
@@ -360,8 +383,13 @@ public class Thread extends CObject implements ICDIThread {
 	 * @see org.eclipse.cdt.debug.core.cdi.model.ICDIExecuteStep#stepOverInstruction(int)
 	 */
 	public void stepOverInstruction(int count) throws CDIException {
-		((Target)getTarget()).setCurrentThread(this);
+		((Target)getTarget()).lockTarget();
-		getTarget().stepOverInstruction(count);
+		try {
+			((Target)getTarget()).setCurrentThread(this);
+			getTarget().stepOverInstruction(count);
+		} finally {
+			((Target)getTarget()).releaseTarget();			
+		}
 	}
 
 	/**
@@ -382,9 +410,14 @@ public class Thread extends CObject implements ICDIThread {
 	 * @see org.eclipse.cdt.debug.core.cdi.model.ICDIExecuteStep#stepUntil(org.eclipse.cdt.debug.core.cdi.ICDILocation)
 	 */
 	public void stepUntil(ICDILocation location) throws CDIException {
-		((Target)getTarget()).setCurrentThread(this);
+		((Target)getTarget()).lockTarget();
-		getTarget().stepUntil(location);
+		try {
-	}
+			((Target)getTarget()).setCurrentThread(this);
+			getTarget().stepUntil(location);
+		} finally {
+			((Target)getTarget()).releaseTarget();			
+		}
+}
 
 	/**
 	 * @see org.eclipse.cdt.debug.core.cdi.model.ICDIThread#isSuspended()
@@ -412,26 +445,38 @@ public class Thread extends CObject implements ICDIThread {
 	 */
 
 	public void resume(boolean passSignal) throws CDIException {
-		((Target)getTarget()).setCurrentThread(this);
+		((Target)getTarget()).lockTarget();
-		getTarget().resume(passSignal);
+		try {
+			((Target)getTarget()).setCurrentThread(this);
+			getTarget().resume(passSignal);
+		} finally {
+			((Target)getTarget()).releaseTarget();			
+		}
 	}
 	/* (non-Javadoc)
 	 * @see org.eclipse.cdt.debug.core.cdi.model.ICDIExecuteResume#resume(org.eclipse.cdt.debug.core.cdi.ICDILocation)
 	 */
 	public void resume(ICDILocation location) throws CDIException {
-		// TODO Auto-generated method stub
+		((Target)getTarget()).lockTarget();
-		((Target)getTarget()).setCurrentThread(this);
+		try {
-		getTarget().resume(location);
+			((Target)getTarget()).setCurrentThread(this);
-		
+			getTarget().resume(location);
+		} finally {
+			((Target)getTarget()).releaseTarget();			
+		}
 	}
 
 	/* (non-Javadoc)
 	 * @see org.eclipse.cdt.debug.core.cdi.model.ICDIExecuteResume#resume(org.eclipse.cdt.debug.core.cdi.model.ICDISignal)
 	 */
 	public void resume(ICDISignal signal) throws CDIException {
-		((Target)getTarget()).setCurrentThread(this);
+		((Target)getTarget()).lockTarget();
-		getTarget().resume(signal);
+		try {
-		
+			((Target)getTarget()).setCurrentThread(this);
+			getTarget().resume(signal);
+		} finally {
+			((Target)getTarget()).releaseTarget();			
+		}
 	}
 
 	/**

debug/org.eclipse.cdt.debug.mi.core/cdi/org/eclipse/cdt/debug/mi/core/cdi/model/VariableDescriptor.java

@@ -240,17 +240,18 @@ public abstract class VariableDescriptor extends CObject implements ICDIVariable
 			StackFrame currentFrame = currentThread.getCurrentStackFrame();
 			StackFrame frame = (StackFrame)getStackFrame();
 			Thread thread = (Thread)getThread();
-			if (frame != null) {
+			target.lockTarget();
-				target.setCurrentThread(frame.getThread(), false);				
-				((Thread)frame.getThread()).setCurrentStackFrame(frame, false);
-			} else if (thread != null) {
-				target.setCurrentThread(thread, false);				
-			}
-			MISession mi = target.getMISession();
-			CommandFactory factory = mi.getCommandFactory();
-			String exp = "sizeof(" + getTypeName() + ")"; //$NON-NLS-1$ //$NON-NLS-2$
-			MIDataEvaluateExpression evaluate = factory.createMIDataEvaluateExpression(exp);
 			try {
+				if (frame != null) {
+					target.setCurrentThread(frame.getThread(), false);				
+					((Thread)frame.getThread()).setCurrentStackFrame(frame, false);
+				} else if (thread != null) {
+					target.setCurrentThread(thread, false);				
+				}
+				MISession mi = target.getMISession();
+				CommandFactory factory = mi.getCommandFactory();
+				String exp = "sizeof(" + getTypeName() + ")"; //$NON-NLS-1$ //$NON-NLS-2$
+				MIDataEvaluateExpression evaluate = factory.createMIDataEvaluateExpression(exp);
 				mi.postCommand(evaluate);
 				MIDataEvaluateExpressionInfo info = evaluate.getMIDataEvaluateExpressionInfo();
 				if (info == null) {
@@ -260,11 +261,15 @@ public abstract class VariableDescriptor extends CObject implements ICDIVariable
 			} catch (MIException e) {
 				throw new MI2CDIException(e);
 			} finally {
-				if (frame != null) {
+				try {
-					target.setCurrentThread(currentThread, false);
+					if (frame != null) {
-					currentThread.setCurrentStackFrame(currentFrame, false);
+						target.setCurrentThread(currentThread, false);
-				} else if (thread != null) {
+						currentThread.setCurrentStackFrame(currentFrame, false);
-					target.setCurrentThread(currentThread, false);
+					} else if (thread != null) {
+						target.setCurrentThread(currentThread, false);
+					}
+				} finally {
+					target.releaseTarget();
 				}
 			}
 		}