Merge remote-tracking branch 'origin/GP-5459_Dan_fixEmptyStructuredOps' into patch

Ghidra/Features/SystemEmulation/src/test/java/ghidra/pcode/struct/sub/StructuredSleighTest.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.
@@ -16,6 +16,7 @@
 package ghidra.pcode.struct.sub;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
 
 import java.lang.invoke.MethodHandles;
 import java.lang.invoke.MethodHandles.Lookup;
@@ -25,8 +26,7 @@ import org.junit.Before;
 import org.junit.Test;
 
 import ghidra.app.plugin.processors.sleigh.SleighException;
-import ghidra.pcode.exec.PcodeUseropLibrary;
-import ghidra.pcode.exec.SleighPcodeUseropDefinition;
+import ghidra.pcode.exec.*;
 import ghidra.pcode.struct.StructuredSleigh;
 import ghidra.program.model.lang.*;
 import ghidra.program.model.pcode.Varnode;
@@ -238,4 +238,16 @@ public class StructuredSleighTest extends AbstractGhidraHeadlessIntegrationTest
 		// TODO: Test that the generated code compiles in a slaspec file.
 		// It's rejected for injects because "return" is not valid there.
 	}
+
+	@Test
+	public void testEmpty() throws Exception {
+		StructuredSleigh ss = new TestStructuredSleigh() {
+			@StructuredUserop
+			public void my_userop() {
+			}
+		};
+		SleighPcodeUseropDefinition<Object> myUserop = ss.generate().get("my_userop");
+		PcodeProgram program = myUserop.programFor(null, List.of(), PcodeUseropLibrary.nil());
+		assertTrue(program.getCode().isEmpty());
+	}
 }

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

@@ -21,6 +21,7 @@ import java.util.stream.Collectors;
 
 import ghidra.app.plugin.processors.sleigh.*;
 import ghidra.app.plugin.processors.sleigh.template.ConstructTpl;
+import ghidra.app.plugin.processors.sleigh.template.OpTpl;
 import ghidra.pcode.utils.MessageFormattingUtils;
 import ghidra.pcodeCPort.pcoderaw.VarnodeData;
 import ghidra.pcodeCPort.sleighbase.SleighBase;
@@ -149,6 +150,9 @@ public enum SleighProgramCompiler {
 	 */
 	public static ConstructTpl compileTemplate(Language language, PcodeParser parser,
 			String sourceName, String source) {
+		if (source.isBlank()) {
+			return new ConstructTpl(new OpTpl[] {});
+		}
 		return parser.compilePcode(source, sourceName, 1);
 	}
 
@@ -285,7 +289,8 @@ public enum SleighProgramCompiler {
 	 * evaluator p-code program uses its own library as a means of capturing the result; however,
 	 * userop libraries are easily composed. It should be easy to add that feature if needed.
 	 * 
-	 * @param language the languge of the target p-code machine
+	 * @param parser a parser for the given language
+	 * @param language the language of the target p-code machine
 	 * @param expression the Sleigh expression to be evaluated
 	 * @return a p-code program whose {@link PcodeExpression#evaluate(PcodeExecutor)} method will
 	 *         evaluate the expression on the given executor and its state.