Validate that endTag receives same tags as beginTag, when possible

Author: DSouzaM

truffle/src/com.oracle.truffle.api.bytecode.test/src/com/oracle/truffle/api/bytecode/test/TagTest.java

@@ -334,6 +334,46 @@ public void testTagsEmptyErrors() {
         });
     }
 
+    @Test
+    public void testTagsMismatchError() {
+        TagInstrumentationTestRootNode node = parse((b) -> {
+            b.beginRoot(TagTestLanguage.REF.get(null));
+            b.beginReturn();
+            b.beginTag(StatementTag.class, ExpressionTag.class);
+            b.emitLoadConstant(42);
+            b.endTag(StatementTag.class);
+            b.endReturn();
+            b.endRoot();
+        });
+
+        assertInstructions(node,
+                        "load.constant",
+                        "return");
+        assertEquals(42, node.getCallTarget().call());
+
+        // When we include statement tags, they balance, so there should be no errors.
+        List<Event> events = attachEventListener(SourceSectionFilter.newBuilder().tagIs(StandardTags.StatementTag.class).build());
+        assertInstructions(node,
+                        "tag.enter",
+                        "load.constant",
+                        "tag.leave",
+                        "return");
+        assertEquals(42, node.getCallTarget().call());
+
+        List<Instruction> instructions = node.getBytecodeNode().getInstructionsAsList();
+        int enter = instructions.get(0).getBytecodeIndex();
+        int leave = instructions.get(2).getBytecodeIndex();
+
+        assertEvents(node,
+                        events,
+                        new Event(EventKind.ENTER, enter, leave, null, StatementTag.class),
+                        new Event(EventKind.RETURN_VALUE, enter, leave, 42, StatementTag.class));
+
+        // When we include expression tags, the mismatch should be detected.
+        assertFails(() -> attachEventListener(SourceSectionFilter.newBuilder().tagIs(StandardTags.StatementTag.class,
+                        StandardTags.ExpressionTag.class).build()), IllegalArgumentException.class);
+    }
+
     @Test
     public void testStatementsUncached() {
         TagInstrumentationTestRootNode node = parse((b) -> {

truffle/src/com.oracle.truffle.dsl.processor/src/com/oracle/truffle/dsl/processor/bytecode/generator/BytecodeDSLNodeFactory.java

@@ -4371,32 +4371,38 @@ private CodeExecutableElement createEnd(OperationModel operation) {
                     b.statement("markReachable(false)");
                     break;
                 case TAG:
+                    b.declaration(tagNode.asType(), "tagNode", "operationData.node");
+
+                    b.startIf().string("(encodedTags & this.tags) != tagNode.tags").end().startBlock();
+                    emitThrow(b, IllegalArgumentException.class, "\"The tags provided to endTag do not match the tags provided to the corresponding beginTag call.\"");
+                    b.end();
+
+                    // If this tag operation is nested in another, add it to the outer tag tree
                     b.declaration(type(int.class), "sp", "operationSp - 1");
                     b.startWhile().string("sp >= 0").end().startBlock();
                     b.startIf().string("operationStack[sp].data instanceof TagOperationData t").end().startBlock();
                     b.startIf().string("t.children == null").end().startBlock();
                     b.statement("t.children = new ArrayList<>(3)");
                     b.end();
-                    b.statement("t.children.add(operationData.node)");
+                    b.statement("t.children.add(tagNode)");
                     b.statement("break");
                     b.end(); // if
                     b.statement("sp--");
                     b.end(); // while
 
+                    // Otherwise, this tag is the root of a tag tree.
                     b.startIf().string("sp < 0").end().startBlock();
                     b.lineComment("not found");
                     b.startIf().string("tagRoots == null").end().startBlock();
                     b.statement("tagRoots = new ArrayList<>(3)");
                     b.end();
-                    b.statement("tagRoots.add(operationData.node)");
-
-                    b.end();
-                    b.end();
+                    b.statement("tagRoots.add(tagNode)");
+                    b.end(); // while
 
-                    b.declaration(tagNode.asType(), "tagNode", "operationData.node");
                     b.declaration(arrayOf(tagNode.asType()), "children");
                     b.declaration(generic(type(List.class), tagNode.asType()), "operationChildren", "operationData.children");
 
+                    // Set the children array and adopt children.
                     b.startIf().string("operationChildren == null").end().startBlock();
                     b.statement("children = TagNode.EMPTY_ARRAY");
                     b.end().startElseBlock();