8320618: NPE: Cannot invoke "java.lang.constant.ClassDesc.isArray()" because "this.sym" is null

Reviewed-by: alanb

Author: asotona

src/java.base/share/classes/jdk/internal/classfile/impl/StackMapGenerator.java

@@ -1394,7 +1394,7 @@ Type toArray() {
         }
 
         Type getComponent() {
-            if (sym.isArray()) {
+            if (isArray()) {
                 var comp = sym.componentType();
                 if (comp.isPrimitive()) {
                     return switch (comp.descriptorString().charAt(0)) {

test/jdk/jdk/classfile/StackMapsTest.java

@@ -24,7 +24,7 @@
 /*
  * @test
  * @summary Testing Classfile stack maps generator.
- * @bug 8305990 8320222
+ * @bug 8305990 8320222 8320618
  * @build testdata.*
  * @run junit StackMapsTest
  */
@@ -43,7 +43,6 @@
 import java.lang.constant.ClassDesc;
 import java.lang.constant.ConstantDescs;
 import java.lang.constant.MethodTypeDesc;
-import java.util.List;
 import java.lang.reflect.AccessFlag;
 
 /**
@@ -237,6 +236,18 @@ void testClassVersions() throws Exception {
                               .verify(null));
     }
 
+    @Test
+    void testInvalidAALOADStack() {
+        Classfile.of().build(ClassDesc.of("Test"), clb
+                -> clb.withMethodBody("test", ConstantDescs.MTD_void, 0, cob
+                        -> cob.bipush(10)
+                              .anewarray(ConstantDescs.CD_Object)
+                              .lconst_1() //long on stack caused NPE, see 8320618
+                              .aaload()
+                              .astore(2)
+                              .return_()));
+    }
+
     private static final FileSystem JRT = FileSystems.getFileSystem(URI.create("jrt:/"));
 
     private static void testTransformedStackMaps(String classPath, Classfile.Option... options) throws Exception {