GP-4231: Fix emulator step from cache after interrupt

Ghidra/Debug/Debugger/src/main/java/ghidra/app/plugin/core/debug/service/emulation/DebuggerEmulationServicePlugin.java

@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *      http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -43,7 +43,8 @@ import ghidra.app.plugin.core.debug.gui.DebuggerResources;
 import ghidra.app.services.*;
 import ghidra.async.AsyncLazyMap;
 import ghidra.debug.api.control.ControlMode;
-import ghidra.debug.api.emulation.*;
+import ghidra.debug.api.emulation.DebuggerPcodeEmulatorFactory;
+import ghidra.debug.api.emulation.DebuggerPcodeMachine;
 import ghidra.debug.api.tracemgr.DebuggerCoordinates;
 import ghidra.framework.plugintool.*;
 import ghidra.framework.plugintool.annotation.AutoServiceConsumed;
@@ -781,7 +782,12 @@ public class DebuggerEmulationServicePlugin extends Plugin implements DebuggerEm
 			TraceThread eventThread = key.time.getEventThread(key.trace);
 			be.ce.emulator().setSoftwareInterruptMode(SwiMode.IGNORE_STEP);
 			RunResult result = scheduler.run(key.trace, eventThread, be.ce.emulator(), monitor);
-			key = new CacheKey(key.platform, key.time.advanced(result.schedule()));
+			if (result.schedule().hasSteps()) {
+				key = new CacheKey(key.platform, key.time.dropPSteps().advanced(result.schedule()));
+			}
+			else {
+				key = new CacheKey(key.platform, key.time.advanced(result.schedule()));
+			}
 			Msg.info(this, "Stopped emulation at " + key.time);
 			TraceSnapshot destSnap = writeToScratch(key, be.ce);
 			cacheEmulator(key, be.ce);

Ghidra/Debug/Debugger/src/test/java/ghidra/app/plugin/core/debug/service/emulation/DebuggerEmulationServiceTest.java

@@ -38,11 +38,11 @@ import ghidra.app.plugin.core.debug.service.platform.DebuggerPlatformServicePlug
 import ghidra.app.services.DebuggerEmulationService.EmulationResult;
 import ghidra.app.services.DebuggerStaticMappingService;
 import ghidra.app.services.DebuggerTraceManagerService.ActivationCause;
+import ghidra.debug.api.emulation.DebuggerPcodeMachine;
 import ghidra.debug.api.platform.DebuggerPlatformMapper;
 import ghidra.debug.api.tracemgr.DebuggerCoordinates;
 import ghidra.pcode.emu.PcodeThread;
-import ghidra.pcode.exec.DecodePcodeExecutionException;
+import ghidra.pcode.exec.*;
-import ghidra.pcode.exec.InterruptPcodeExecutionException;
 import ghidra.pcode.utils.Utils;
 import ghidra.program.model.address.Address;
 import ghidra.program.model.address.AddressSpace;
@@ -489,25 +489,180 @@ public class DebuggerEmulationServiceTest extends AbstractGhidraHeadedDebuggerTe
 			trace.getBreakpointManager()
 					.addBreakpoint("Breakpoints[0]", Lifespan.nowOn(0), addrText, Set.of(thread),
 						Set.of(TraceBreakpointKind.SW_EXECUTE), true, "test");
-			trace.getBreakpointManager()
+			TraceBreakpoint tb = trace.getBreakpointManager()
 					.addBreakpoint("Breakpoints[1]", Lifespan.nowOn(0), addrI1, Set.of(thread),
 						Set.of(TraceBreakpointKind.SW_EXECUTE), true, "test");
+			// Force "partial instruction"
+			tb.setEmuSleigh("""
+					r1 = 0xbeef;
+					emu_swi();
+					emu_exec_decoded();
+					""");
 			trace.getBreakpointManager()
 					.addBreakpoint("Breakpoints[2]", Lifespan.nowOn(0), addrI2, Set.of(thread),
 						Set.of(TraceBreakpointKind.SW_EXECUTE), true, "test");
 		}
 
+		assertEquals(0, emulationPlugin.cache.size());
+
 		// This is already testing if the one set at the entry is ignored
 		EmulationResult result1 = emulationPlugin.run(trace.getPlatformManager().getHostPlatform(),
 			TraceSchedule.snap(0), monitor, Scheduler.oneThread(thread));
-		assertEquals(TraceSchedule.snap(0).steppedForward(thread, 1), result1.schedule());
+		assertEquals(TraceSchedule.snap(0)
+				.steppedForward(thread, 1)
+				.steppedPcodeForward(thread, 2),
+			result1.schedule());
 		assertTrue(result1.error() instanceof InterruptPcodeExecutionException);
 
+		// Save this for comparison later
+		DebuggerPcodeMachine<?> emu = Unique.assertOne(emulationPlugin.cache.values()).emulator();
+
 		// This will test if the one just hit gets ignored
 		EmulationResult result2 = emulationPlugin.run(trace.getPlatformManager().getHostPlatform(),
 			result1.schedule(), monitor, Scheduler.oneThread(thread));
 		assertEquals(TraceSchedule.snap(0).steppedForward(thread, 2), result2.schedule());
 		assertTrue(result1.error() instanceof InterruptPcodeExecutionException);
+
+		// For efficiency, esp. after a long run, make sure we used the same emulator
+		assertSame(emu, Unique.assertOne(emulationPlugin.cache.values()).emulator());
+	}
+
+	@Test
+	public void testStepAfterExecutionBreakpoint() throws Exception {
+		createProgram();
+		intoProject(program);
+		Assembler asm = Assemblers.getAssembler(program);
+		Memory memory = program.getMemory();
+		Address addrText = addr(program, 0x00400000);
+		Address addrI1;
+		try (Transaction tx = program.openTransaction("Initialize")) {
+			MemoryBlock blockText = memory.createInitializedBlock(".text", addrText, 0x1000,
+				(byte) 0, TaskMonitor.DUMMY, false);
+			blockText.setExecute(true);
+			InstructionIterator ii = asm.assemble(addrText,
+				"mov r0, r0",
+				"mov r0, r1",
+				"mov r2, r0");
+			ii.next(); // addrText
+			addrI1 = ii.next().getMinAddress();
+		}
+
+		programManager.openProgram(program);
+		waitForSwing();
+		codeBrowser.goTo(new ProgramLocation(program, addrText));
+		waitForSwing();
+
+		performEnabledAction(codeBrowser.getProvider(), emulationPlugin.actionEmulateProgram, true);
+
+		Trace trace = traceManager.getCurrentTrace();
+		assertNotNull(trace);
+
+		TraceThread thread = Unique.assertOne(trace.getThreadManager().getAllThreads());
+
+		try (Transaction tx = trace.openTransaction("Add breakpoint")) {
+			trace.getBreakpointManager()
+					.addBreakpoint("Breakpoints[0]", Lifespan.nowOn(0), addrText, Set.of(thread),
+						Set.of(TraceBreakpointKind.SW_EXECUTE), true, "test");
+			TraceBreakpoint tb = trace.getBreakpointManager()
+					.addBreakpoint("Breakpoints[1]", Lifespan.nowOn(0), addrI1, Set.of(thread),
+						Set.of(TraceBreakpointKind.SW_EXECUTE), true, "test");
+			// Force "partial instruction"
+			tb.setEmuSleigh("""
+					r1 = 0xbeef;
+					emu_swi();
+					emu_exec_decoded();
+					""");
+		}
+
+		assertEquals(0, emulationPlugin.cache.size());
+
+		// This is already testing if the one set at the entry is ignored
+		EmulationResult result1 = emulationPlugin.run(trace.getPlatformManager().getHostPlatform(),
+			TraceSchedule.snap(0), monitor, Scheduler.oneThread(thread));
+		assertEquals(TraceSchedule.snap(0)
+				.steppedForward(thread, 1)
+				.steppedPcodeForward(thread, 2),
+			result1.schedule());
+		assertTrue(result1.error() instanceof InterruptPcodeExecutionException);
+
+		// Save this for comparison later
+		DebuggerPcodeMachine<?> emu = Unique.assertOne(emulationPlugin.cache.values()).emulator();
+
+		// Now, step it forward to complete the instruction
+		emulationPlugin.emulate(trace.getPlatformManager().getHostPlatform(),
+			TraceSchedule.snap(0).steppedForward(thread, 2), monitor);
+
+		// For efficiency, esp. after a long run, make sure we used the same emulator
+		assertSame(emu, Unique.assertOne(emulationPlugin.cache.values()).emulator());
+	}
+
+	@Test
+	public void testStuckAtUserop() throws Exception {
+		createProgram();
+		intoProject(program);
+		Assembler asm = Assemblers.getAssembler(program);
+		Memory memory = program.getMemory();
+		Address addrText = addr(program, 0x00400000);
+		Address addrI1;
+		try (Transaction tx = program.openTransaction("Initialize")) {
+			MemoryBlock blockText = memory.createInitializedBlock(".text", addrText, 0x1000,
+				(byte) 0, TaskMonitor.DUMMY, false);
+			blockText.setExecute(true);
+			InstructionIterator ii = asm.assemble(addrText,
+				"mov r0, r0",
+				"mov r0, r1",
+				"mov r2, r0");
+			ii.next(); // addrText
+			addrI1 = ii.next().getMinAddress();
+		}
+
+		programManager.openProgram(program);
+		waitForSwing();
+		codeBrowser.goTo(new ProgramLocation(program, addrText));
+		waitForSwing();
+
+		performEnabledAction(codeBrowser.getProvider(), emulationPlugin.actionEmulateProgram, true);
+
+		Trace trace = traceManager.getCurrentTrace();
+		assertNotNull(trace);
+
+		TraceThread thread = Unique.assertOne(trace.getThreadManager().getAllThreads());
+
+		try (Transaction tx = trace.openTransaction("Add breakpoint")) {
+			TraceBreakpoint tb = trace.getBreakpointManager()
+					.addBreakpoint("Breakpoints[1]", Lifespan.nowOn(0), addrI1, Set.of(thread),
+						Set.of(TraceBreakpointKind.SW_EXECUTE), true, "test");
+			// Force "partial instruction"
+			tb.setEmuSleigh("""
+					r1 = 0xbeef;
+					pcodeop_one(r1);
+					emu_exec_decoded();
+					""");
+		}
+
+		TraceSchedule stuck = TraceSchedule.snap(0)
+				.steppedForward(thread, 1)
+				.steppedPcodeForward(thread, 2);
+
+		assertEquals(0, emulationPlugin.cache.size());
+
+		// This is already testing if the one set at the entry is ignored
+		EmulationResult result1 = emulationPlugin.run(trace.getPlatformManager().getHostPlatform(),
+			TraceSchedule.snap(0), monitor, Scheduler.oneThread(thread));
+		assertEquals(stuck, result1.schedule());
+		assertTrue(result1.error() instanceof PcodeExecutionException);
+
+		// Save this for comparison later
+		DebuggerPcodeMachine<?> emu = Unique.assertOne(emulationPlugin.cache.values()).emulator();
+
+		// We shouldn't get any further
+		EmulationResult result2 = emulationPlugin.run(trace.getPlatformManager().getHostPlatform(),
+			result1.schedule(), monitor, Scheduler.oneThread(thread));
+		assertEquals(stuck, result2.schedule());
+		assertTrue(result1.error() instanceof PcodeExecutionException);
+
+		// For efficiency, esp. after a long run, make sure we used the same emulator
+		assertSame(emu, Unique.assertOne(emulationPlugin.cache.values()).emulator());
 	}
 
 	@Test
@@ -817,6 +972,7 @@ public class DebuggerEmulationServiceTest extends AbstractGhidraHeadedDebuggerTe
 				newSnap, program, tb.addr(0x00400000), addr(program, 0x00400000));
 			newTraceThread.setName("MyThread");
 
+			@SuppressWarnings("unused")
 			PcodeThread<byte[]> newEmuThread = emulator.newThread(newTraceThread.getPath());
 		}
 	}

Ghidra/Debug/Framework-TraceModeling/src/main/java/ghidra/trace/model/time/schedule/PatchStep.java

@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *      http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -232,6 +232,11 @@ public class PatchStep implements Step {
 		return StepType.PATCH;
 	}
 
+	@Override
+	public long getSkipCount() {
+		return 0;
+	}
+
 	@Override
 	public boolean isNop() {
 		// TODO: If parsing beforehand, base on number of ops
@@ -307,7 +312,7 @@ public class PatchStep implements Step {
 	}
 
 	@Override
-	public <T> void execute(PcodeThread<T> emuThread, Stepper stepper, TaskMonitor monitor)
+	public void execute(PcodeThread<?> emuThread, Stepper stepper, TaskMonitor monitor)
 			throws CancelledException {
 		emuThread.stepPatch(sleigh);
 	}

Ghidra/Debug/Framework-TraceModeling/src/main/java/ghidra/trace/model/time/schedule/Scheduler.java

@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *      http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -81,14 +81,17 @@ public interface Scheduler {
 
 	/**
 	 * The result of running a machine
+	 * 
+	 * @param schedule the actual schedule executed
+	 * @param error if applicable, the error that interrupted execution
 	 */
-	record RecordRunResult(TraceSchedule schedule, Throwable error) implements RunResult {
+	record RecordRunResult(TraceSchedule schedule, Throwable error) implements RunResult {}
-	}
 
 	/**
 	 * Get the next step to schedule
 	 * 
-	 * @return the (instruction-level) thread and tick count
+	 * @param trace the trace being emulated
+	 * @return the thread and (instruction-level) tick count
 	 */
 	TickStep nextSlice(Trace trace);
 
@@ -118,12 +121,17 @@ public interface Scheduler {
 				TickStep slice = nextSlice(trace);
 				eventThread = slice.getThread(tm, eventThread);
 				emuThread = machine.getThread(eventThread.getPath(), true);
-				if (emuThread.getFrame() != null) {
+				long ticksLeft = slice.tickCount;
+				if (ticksLeft > 0 && emuThread.getFrame() != null) {
+					monitor.checkCancelled();
 					emuThread.finishInstruction();
+					ticksLeft--;
+					completedTicks++;
 				}
-				for (int i = 0; i < slice.tickCount; i++) {
+				while (ticksLeft > 0) {
 					monitor.checkCancelled();
 					emuThread.stepInstruction();
+					ticksLeft--;
 					completedTicks++;
 				}
 				completedSteps = completedSteps.steppedForward(eventThread, completedTicks);
@@ -134,11 +142,11 @@ public interface Scheduler {
 			completedSteps = completedSteps.steppedForward(eventThread, completedTicks);
 			PcodeFrame frame = emuThread.getFrame();
 			if (frame == null) {
-				return new RecordRunResult(completedSteps, e);
+				return new RecordRunResult(completedSteps.assumeRecorded(), e);
 			}
 			// Rewind one so stepping retries the op causing the error
 			frame.stepBack();
-			int count = frame.count();
+			int count = frame.resetCount();
 			if (count == 0) {
 				// If we've decoded, but could not execute the first op, just drop the p-code steps
 				emuThread.dropInstruction();
@@ -146,11 +154,11 @@ public interface Scheduler {
 			}
 			// The +1 accounts for the decode step
 			return new RecordRunResult(
-				completedSteps.steppedPcodeForward(eventThread, count + 1), e);
+				completedSteps.steppedPcodeForward(eventThread, count + 1).assumeRecorded(), e);
 		}
 		catch (CancelledException e) {
 			return new RecordRunResult(
-				completedSteps.steppedForward(eventThread, completedTicks), e);
+				completedSteps.steppedForward(eventThread, completedTicks).assumeRecorded(), e);
 		}
 	}
 }

Ghidra/Debug/Framework-TraceModeling/src/main/java/ghidra/trace/model/time/schedule/Sequence.java

@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *      http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -21,6 +21,7 @@ import java.util.stream.Collectors;
 import org.apache.commons.lang3.StringUtils;
 
 import ghidra.pcode.emu.PcodeMachine;
+import ghidra.pcode.emu.PcodeThread;
 import ghidra.program.model.lang.Language;
 import ghidra.trace.model.Trace;
 import ghidra.trace.model.thread.TraceThread;
@@ -240,7 +241,7 @@ public class Sequence implements Comparable<Sequence> {
 	}
 
 	/**
-	 * Richly compare to sequences
+	 * Richly compare two sequences
 	 * 
 	 * <p>
 	 * The result indicates not only which is "less" or "greater" than the other, but also indicates
@@ -355,6 +356,14 @@ public class Sequence implements Comparable<Sequence> {
 		return count;
 	}
 
+	public long totalSkipCount() {
+		long count = 0;
+		for (Step step : steps) {
+			count += step.getSkipCount();
+		}
+		return count;
+	}
+
 	/**
 	 * Compute to total number of patches specified
 	 * 
@@ -440,4 +449,25 @@ public class Sequence implements Comparable<Sequence> {
 		}
 		return thread;
 	}
+
+	/**
+	 * Check if the first instruction step is actually to finish an incomplete instruction.
+	 * 
+	 * @param thread the thread whose instruction to potentially finish
+	 * @param machine a machine bound to the trace whose current state reflects the given position
+	 * @return if a finish was performed, this sequence with one initial step removed, i.e., a
+	 *         sequence representing the steps remaining
+	 */
+	Sequence checkFinish(TraceThread thread, PcodeMachine<?> machine) {
+		PcodeThread<?> emuThread = machine.getThread(thread.getPath(), true);
+		if (emuThread.getFrame() == null) {
+			return this;
+		}
+		Sequence result = new Sequence(new ArrayList<>(steps));
+		emuThread.finishInstruction();
+		if (result.steps.get(0).rewind(1) == 0) {
+			result.steps.remove(0);
+		}
+		return result;
+	}
 }

Ghidra/Debug/Framework-TraceModeling/src/main/java/ghidra/trace/model/time/schedule/SkipStep.java

@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *      http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -48,6 +48,11 @@ public class SkipStep extends AbstractStep {
 		return StepType.SKIP;
 	}
 
+	@Override
+	public long getSkipCount() {
+		return tickCount;
+	}
+
 	@Override
 	protected String toStringStepPart() {
 		return String.format("s%d", tickCount);
@@ -66,7 +71,7 @@ public class SkipStep extends AbstractStep {
 	}
 
 	@Override
-	public <T> void execute(PcodeThread<T> emuThread, Stepper stepper, TaskMonitor monitor)
+	public void execute(PcodeThread<?> emuThread, Stepper stepper, TaskMonitor monitor)
 			throws CancelledException {
 		for (int i = 0; i < tickCount; i++) {
 			monitor.incrementProgress(1);

Ghidra/Debug/Framework-TraceModeling/src/main/java/ghidra/trace/model/time/schedule/Step.java

@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *      http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -116,6 +116,8 @@ public interface Step extends Comparable<Step> {
 
 	long getTickCount();
 
+	long getSkipCount();
+
 	long getPatchCount();
 
 	/**
@@ -147,7 +149,7 @@ public interface Step extends Comparable<Step> {
 	 * method sets the count to 0 and returns the (positive) difference, indicating this step should
 	 * be removed from the sequence, and the remaining steps rewound from the preceding step.
 	 * 
-	 * @param steps the count to rewind
+	 * @param count the count to rewind
 	 * @return the number of steps remaining
 	 */
 	long rewind(long count);
@@ -155,7 +157,7 @@ public interface Step extends Comparable<Step> {
 	/**
 	 * Richly compare this step to another
 	 * 
-	 * @param step the object of comparison (this being the subject)
+	 * @param that the object of comparison (this being the subject)
 	 * @return a result describing the relationship from subject to object
 	 */
 	CompareResult compareStep(Step that);
@@ -183,7 +185,7 @@ public interface Step extends Comparable<Step> {
 		return thread;
 	}
 
-	<T> void execute(PcodeThread<T> emuThread, Stepper stepper, TaskMonitor monitor)
+	void execute(PcodeThread<?> emuThread, Stepper stepper, TaskMonitor monitor)
 			throws CancelledException;
 
 	long coalescePatches(Language language, List<Step> steps);

Ghidra/Debug/Framework-TraceModeling/src/main/java/ghidra/trace/model/time/schedule/TickStep.java

@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *      http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -48,6 +48,11 @@ public class TickStep extends AbstractStep {
 		return StepType.TICK;
 	}
 
+	@Override
+	public long getSkipCount() {
+		return 0;
+	}
+
 	@Override
 	protected String toStringStepPart() {
 		return Long.toString(tickCount);
@@ -66,7 +71,7 @@ public class TickStep extends AbstractStep {
 	}
 
 	@Override
-	public <T> void execute(PcodeThread<T> emuThread, Stepper stepper, TaskMonitor monitor)
+	public void execute(PcodeThread<?> emuThread, Stepper stepper, TaskMonitor monitor)
 			throws CancelledException {
 		for (int i = 0; i < tickCount; i++) {
 			monitor.incrementProgress(1);

Ghidra/Debug/Framework-TraceModeling/src/main/java/ghidra/trace/model/time/schedule/TraceSchedule.java

@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *      http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -39,7 +39,7 @@ public class TraceSchedule implements Comparable<TraceSchedule> {
 	 * @return the schedule
 	 */
 	public static final TraceSchedule snap(long snap) {
-		return new TraceSchedule(snap, new Sequence(), new Sequence());
+		return new TraceSchedule(snap, new Sequence(), new Sequence(), Source.RECORD);
 	}
 
 	private static final String PARSE_ERR_MSG =
@@ -55,9 +55,10 @@ public class TraceSchedule implements Comparable<TraceSchedule> {
 	 * threads forward, and/or patching machine state.
 	 * 
 	 * @param spec the string specification
+	 * @param source the presumed source of the schedule
 	 * @return the parsed schedule
 	 */
-	public static TraceSchedule parse(String spec) {
+	public static TraceSchedule parse(String spec, Source source) {
 		String[] parts = spec.split(":", 2);
 		if (parts.length > 2) {
 			throw new AssertionError();
@@ -98,24 +99,76 @@ public class TraceSchedule implements Comparable<TraceSchedule> {
 			ticks = new Sequence();
 			pTicks = new Sequence();
 		}
-		return new TraceSchedule(snap, ticks, pTicks);
+		return new TraceSchedule(snap, ticks, pTicks, source);
+	}
+
+	/**
+	 * As in {@link #parse(String, Source)}, but assumed abnormal
+	 * 
+	 * @param spec the string specification
+	 * @return the parsed schedule
+	 */
+	public static TraceSchedule parse(String spec) {
+		return parse(spec, Source.INPUT);
+	}
+
+	public enum Source {
+		/**
+		 * The schedule comes from the user or some source other than a recorded emulation schedule.
+		 */
+		INPUT {
+			@Override
+			Source adjust(long pTickCount, long pPatchCount, long pSkipCount) {
+				// The first tick is decode, so <= 1 tick is definitely not a full instruction
+				return pTickCount <= 1 && pPatchCount == 0 && pSkipCount == 0 ? RECORD : INPUT;
+			}
+		},
+		/**
+		 * The schedule comes from recording actual emulation.
+		 * 
+		 * <p>
+		 * Specifically, the p-code steps must be known not to exceed one instruction.
+		 */
+		RECORD {
+			@Override
+			Source adjust(long pTickCount, long pPatchCount, long pSkipCount) {
+				return pPatchCount == 0 && pSkipCount == 0 ? RECORD : INPUT;
+			}
+		};
+
+		abstract Source adjust(long tickCount, long patchCount, long skipCount);
 	}
 
 	private final long snap;
 	private final Sequence steps;
 	private final Sequence pSteps;
+	private final Source source;
 
 	/**
 	 * Construct the given schedule
 	 * 
 	 * @param snap the initial trace snapshot
 	 * @param steps the step sequence
-	 * @param pSteps the of p-code step sequence
+	 * @param pSteps the p-code step sequence
+	 * @param source if the p-code steps are known not to exceed one instruction
 	 */
-	public TraceSchedule(long snap, Sequence steps, Sequence pSteps) {
+	public TraceSchedule(long snap, Sequence steps, Sequence pSteps, Source source) {
 		this.snap = snap;
 		this.steps = steps;
 		this.pSteps = pSteps;
+		this.source = source.adjust(pSteps.totalTickCount(), pSteps.totalPatchCount(),
+			pSteps.totalSkipCount());
+	}
+
+	/**
+	 * Construct the given schedule, but assumed abnormal
+	 * 
+	 * @param snap the initial trace snapshot
+	 * @param steps the step sequence
+	 * @param pSteps the p-code step sequence
+	 */
+	public TraceSchedule(long snap, Sequence steps, Sequence pSteps) {
+		this(snap, steps, pSteps, Source.INPUT);
 	}
 
 	@Override
@@ -152,33 +205,17 @@ public class TraceSchedule implements Comparable<TraceSchedule> {
 		}
 
 		result = this.steps.compareSeq(that.steps);
-		switch (result) {
-			case UNREL_LT:
-			case UNREL_GT:
-				return result;
-			case REL_LT:
-				if (this.pSteps.isNop()) {
-					return CompareResult.REL_LT;
-				}
-				else {
-					return CompareResult.UNREL_LT;
-				}
-			case REL_GT:
-				if (that.pSteps.isNop()) {
-					return CompareResult.REL_GT;
-				}
-				else {
-					return CompareResult.UNREL_GT;
-				}
-			default: // EQUALS, compare pSteps
-		}
 
-		result = this.pSteps.compareSeq(that.pSteps);
+		return switch (result) {
-		if (result != CompareResult.EQUALS) {
+			case UNREL_LT, UNREL_GT -> result;
-			return result;
+			case REL_LT -> (this.pSteps.isNop() || this.source == Source.RECORD)
-		}
+					? CompareResult.REL_LT
-
+					: CompareResult.UNREL_LT;
-		return CompareResult.EQUALS;
+			case REL_GT -> (that.pSteps.isNop() || that.source == Source.RECORD)
+					? CompareResult.REL_GT
+					: CompareResult.UNREL_GT;
+			default -> this.pSteps.compareSeq(that.pSteps);
+		};
 	}
 
 	@Override
@@ -222,10 +259,19 @@ public class TraceSchedule implements Comparable<TraceSchedule> {
 		return steps.isNop() && pSteps.isNop();
 	}
 
+	/**
+	 * Check if this schedule has instruction steps
+	 * 
+	 * @return true if this indicates at least one instruction step
+	 */
+	public boolean hasSteps() {
+		return !steps.isNop();
+	}
+
 	/**
 	 * Get the source snapshot
 	 * 
-	 * @return
+	 * @return the snapshot key
 	 */
 	public long getSnap() {
 		return snap;
@@ -234,7 +280,7 @@ public class TraceSchedule implements Comparable<TraceSchedule> {
 	/**
 	 * Get the last thread key stepped by this schedule
 	 * 
-	 * @return
+	 * @return the thread key
 	 */
 	public long getLastThreadKey() {
 		long last = pSteps.getLastThreadKey();
@@ -396,6 +442,7 @@ public class TraceSchedule implements Comparable<TraceSchedule> {
 				pRemains.execute(trace, lastThread, machine, Stepper.pcode(), monitor);
 		}
 		else {
+			remains = remains.checkFinish(lastThread, machine);
 			lastThread =
 				remains.execute(trace, lastThread, machine, Stepper.instruction(), monitor);
 			lastThread = pSteps.execute(trace, lastThread, machine, Stepper.pcode(), monitor);
@@ -417,7 +464,7 @@ public class TraceSchedule implements Comparable<TraceSchedule> {
 	public TraceSchedule steppedForward(TraceThread thread, long tickCount) {
 		Sequence steps = this.steps.clone();
 		steps.advance(new TickStep(thread == null ? -1 : thread.getKey(), tickCount));
-		return new TraceSchedule(snap, steps, new Sequence());
+		return new TraceSchedule(snap, steps, new Sequence(), Source.RECORD);
 	}
 
 	/**
@@ -430,7 +477,7 @@ public class TraceSchedule implements Comparable<TraceSchedule> {
 	public TraceSchedule skippedForward(TraceThread thread, long tickCount) {
 		Sequence steps = this.steps.clone();
 		steps.advance(new SkipStep(thread == null ? -1 : thread.getKey(), tickCount));
-		return new TraceSchedule(snap, steps, new Sequence());
+		return new TraceSchedule(snap, steps, new Sequence(), Source.RECORD);
 	}
 
 	protected TraceSchedule doSteppedBackward(Trace trace, long tickCount, Set<Long> visited) {
@@ -454,7 +501,7 @@ public class TraceSchedule implements Comparable<TraceSchedule> {
 		}
 		Sequence steps = this.steps.clone();
 		steps.rewind(tickCount);
-		return new TraceSchedule(snap, steps, new Sequence());
+		return new TraceSchedule(snap, steps, new Sequence(), Source.RECORD);
 	}
 
 	/**
@@ -486,7 +533,7 @@ public class TraceSchedule implements Comparable<TraceSchedule> {
 	public TraceSchedule steppedPcodeForward(TraceThread thread, int pTickCount) {
 		Sequence pTicks = this.pSteps.clone();
 		pTicks.advance(new TickStep(thread == null ? -1 : thread.getKey(), pTickCount));
-		return new TraceSchedule(snap, steps.clone(), pTicks);
+		return new TraceSchedule(snap, steps.clone(), pTicks, Source.INPUT);
 	}
 
 	/**
@@ -499,7 +546,7 @@ public class TraceSchedule implements Comparable<TraceSchedule> {
 	public TraceSchedule skippedPcodeForward(TraceThread thread, int pTickCount) {
 		Sequence pTicks = this.pSteps.clone();
 		pTicks.advance(new SkipStep(thread == null ? -1 : thread.getKey(), pTickCount));
-		return new TraceSchedule(snap, steps.clone(), pTicks);
+		return new TraceSchedule(snap, steps.clone(), pTicks, Source.INPUT);
 	}
 
 	/**
@@ -519,7 +566,7 @@ public class TraceSchedule implements Comparable<TraceSchedule> {
 		}
 		Sequence pTicks = this.pSteps.clone();
 		pTicks.rewind(pStepCount);
-		return new TraceSchedule(snap, steps.clone(), pTicks);
+		return new TraceSchedule(snap, steps.clone(), pTicks, Source.INPUT);
 	}
 
 	private long keyOf(TraceThread thread) {
@@ -530,6 +577,7 @@ public class TraceSchedule implements Comparable<TraceSchedule> {
 	 * Returns the equivalent of executing this schedule then performing a given patch
 	 * 
 	 * @param thread the thread context for the patch; cannot be null
+	 * @param language the sleigh language for the patch
 	 * @param sleigh a single line of sleigh, excluding the terminating semicolon.
 	 * @return the resulting schedule
 	 */
@@ -538,19 +586,20 @@ public class TraceSchedule implements Comparable<TraceSchedule> {
 			Sequence pTicks = this.pSteps.clone();
 			pTicks.advance(new PatchStep(thread.getKey(), sleigh));
 			pTicks.coalescePatches(language);
-			return new TraceSchedule(snap, steps.clone(), pTicks);
+			return new TraceSchedule(snap, steps.clone(), pTicks, Source.INPUT);
 		}
 		Sequence ticks = this.steps.clone();
 		ticks.advance(new PatchStep(keyOf(thread), sleigh));
 		ticks.coalescePatches(language);
-		return new TraceSchedule(snap, ticks, new Sequence());
+		return new TraceSchedule(snap, ticks, new Sequence(), Source.RECORD);
 	}
 
 	/**
 	 * Returns the equivalent of executing this schedule then performing the given patches
 	 * 
 	 * @param thread the thread context for the patch; cannot be null
-	 * @param sleigh the lines of sleigh, excluding the terminating semicolons.
+	 * @param language the sleigh language for the patch
+	 * @param sleigh the lines of sleigh, excluding the terminating semicolons
 	 * @return the resulting schedule
 	 */
 	public TraceSchedule patched(TraceThread thread, Language language, List<String> sleigh) {
@@ -560,14 +609,14 @@ public class TraceSchedule implements Comparable<TraceSchedule> {
 				pTicks.advance(new PatchStep(thread.getKey(), line));
 			}
 			pTicks.coalescePatches(language);
-			return new TraceSchedule(snap, steps.clone(), pTicks);
+			return new TraceSchedule(snap, steps.clone(), pTicks, Source.INPUT);
 		}
 		Sequence ticks = this.steps.clone();
 		for (String line : sleigh) {
 			ticks.advance(new PatchStep(thread.getKey(), line));
 		}
 		ticks.coalescePatches(language);
-		return new TraceSchedule(snap, ticks, new Sequence());
+		return new TraceSchedule(snap, ticks, new Sequence(), Source.RECORD);
 	}
 
 	/**
@@ -575,7 +624,7 @@ public class TraceSchedule implements Comparable<TraceSchedule> {
 	 * 
 	 * <p>
 	 * This operation cannot be used to append instruction steps after p-code steps. Thus, if this
-	 * schedule contains any p-code steps and {@code} next has instruction steps, an error will be
+	 * schedule contains any p-code steps and {@code next} has instruction steps, an error will be
 	 * 
 	 * @param next the schedule to append. Its snap is ignored.
 	 * @return the complete schedule
@@ -586,16 +635,25 @@ public class TraceSchedule implements Comparable<TraceSchedule> {
 		if (this.pSteps.isNop()) {
 			Sequence ticks = this.steps.clone();
 			ticks.advance(next.steps);
-			return new TraceSchedule(this.snap, ticks, next.pSteps.clone());
+			return new TraceSchedule(this.snap, ticks, next.pSteps.clone(), next.source);
 		}
 		else if (next.steps.isNop()) {
-			Sequence pTicks = this.steps.clone();
+			Sequence pTicks = this.pSteps.clone();
 			pTicks.advance(next.pSteps);
-			return new TraceSchedule(this.snap, this.steps.clone(), pTicks);
+			return new TraceSchedule(this.snap, this.steps.clone(), pTicks, Source.INPUT);
 		}
 		throw new IllegalArgumentException("Cannot have instructions steps following p-code steps");
 	}
 
+	/**
+	 * Drop the p-code steps
+	 * 
+	 * @return the schedule without ops
+	 */
+	public TraceSchedule dropPSteps() {
+		return new TraceSchedule(this.snap, this.steps, new Sequence());
+	}
+
 	/**
 	 * Get the threads involved in the schedule
 	 * 
@@ -611,4 +669,8 @@ public class TraceSchedule implements Comparable<TraceSchedule> {
 		result.remove(null);
 		return result;
 	}
+
+	public TraceSchedule assumeRecorded() {
+		return new TraceSchedule(snap, steps, pSteps, Source.RECORD);
+	}
 }

Ghidra/Debug/Framework-TraceModeling/src/test/java/ghidra/trace/model/time/schedule/TraceScheduleTest.java

@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *      http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -224,19 +224,30 @@ public class TraceScheduleTest extends AbstractGhidraHeadlessIntegrationTest {
 		expectU("0:10", "1:10");
 		expectU("0:t0-10", "0:t1-10");
 		// We don't know how many p-code steps complete an instruction step
-		expectU("0:t0-10.1", "0:t0-11");
+		// But we need at least 2 to actually enter the instruction
+		expectU("0:t0-10.2", "0:t0-11");
 		expectU("0:t0-10;t1-5", "0:t0-11;t1-5");
 
 		expectR("0:t0-10", "0:t0-11");
 		expectR("0:t0-10", "0:t0-10;t1-5");
 		expectR("0:t0-10", "0:t0-11;t1-5");
-		expectR("0:t0-10", "0:t0-10.1");
+		expectR("0:t0-10", "0:t0-10.2");
-		expectR("0:t0-10", "0:t0-11.1");
+		expectR("0:t0-10", "0:t0-11.2");
-		expectR("0:t0-10", "0:t0-10;t1-5.1");
+		expectR("0:t0-10", "0:t0-10;t1-5.2");
-		expectR("0:t0-10", "0:t0-11;t1-5.1");
+		expectR("0:t0-10", "0:t0-11;t1-5.2");
 
 		expectE("0:t0-10", "0:t0-10");
-		expectE("0:t0-10.1", "0:t0-10.1");
+		expectE("0:t0-10.2", "0:t0-10.2");
+	}
+
+	@Test
+	public void testCompare2() {
+		TraceSchedule timeL = TraceSchedule.parse("0:t0-2.5");
+		TraceSchedule timeR = TraceSchedule.parse("0:t0-3");
+
+		assertEquals(CompareResult.UNREL_LT, timeL.compareSchedule(timeR));
+		assertEquals(CompareResult.REL_LT, timeL.assumeRecorded().compareSchedule(timeR));
+		assertEquals(CompareResult.UNREL_LT, timeL.compareSchedule(timeR.assumeRecorded()));
 	}
 
 	public String strRelativize(String fromSpec, String toSpec) {

Ghidra/Framework/Emulation/src/main/java/ghidra/pcode/emu/DefaultPcodeThread.java

@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *      http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -400,6 +400,7 @@ public class DefaultPcodeThread<T> implements PcodeThread<T> {
 
 	@Override
 	public void stepInstruction() {
+		assertCompletedInstruction();
 		PcodeProgram inj = getInject(counter);
 		if (inj != null) {
 			instruction = null;
@@ -576,7 +577,6 @@ public class DefaultPcodeThread<T> implements PcodeThread<T> {
 
 	@Override
 	public void executeInstruction() {
-		assertCompletedInstruction();
 		instruction = decoder.decodeInstruction(counter, context);
 		PcodeProgram insProg = PcodeProgram.fromInstruction(instruction);
 		preExecuteInstruction();

Ghidra/Framework/Emulation/src/main/java/ghidra/pcode/exec/PcodeFrame.java

@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *      http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -159,7 +159,7 @@ public class PcodeFrame {
 	}
 
 	/**
-	 * The number of p-code ops executed
+	 * Get and reset the number of p-code ops executed
 	 * 
 	 * <p>
 	 * Contrast this to {@link #index()}, which marks the next op to be executed. This counts the
@@ -167,7 +167,9 @@ public class PcodeFrame {
 	 * 
 	 * @return the count
 	 */
-	public int count() {
+	public int resetCount() {
+		int count = this.count;
+		this.count = 0;
 		return count;
 	}