Fix NULL values for INSTANCEOF and CAST.

src/de/inetsoftware/jwebassembly/binary/BinaryModuleWriter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2017 - 2021 Volker Berlin (i-net software)
+ * Copyright 2017 - 2022 Volker Berlin (i-net software)
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -1328,6 +1328,10 @@ public class BinaryModuleWriter extends ModuleWriter implements InstructionOpcod
                     codeStream.writeVaruint32( i );
                 }
                 break;
+            case BR_ON_NULL:
+                codeStream.writeOpCode( BR_ON_NULL );
+                codeStream.writeVaruint32( (Integer)data );
+                break;
             case LOOP:
                 codeStream.writeOpCode( LOOP );
                 codeStream.writeValueType( ValueType.empty ); // void; the return type of the loop. currently we does not use it

src/de/inetsoftware/jwebassembly/module/TypeManager.java

@@ -514,6 +514,8 @@ public class TypeManager {
     WatCodeSyntheticFunctionName createInstanceOf() {
         return new WatCodeSyntheticFunctionName( //
                         "instanceof", "local.get 0 " // THIS
+                                        + "ref.is_null if i32.const 0 return end " // NULL check
+                                        + "local.get 0 " // THIS
                                         + "struct.get java/lang/Object .vtable " // vtable is on index 0
                                         + "local.tee 2 " // save the vtable location
                                         + "i32.load offset=" + TYPE_DESCRIPTION_INSTANCEOF_OFFSET + " align=4 " // get offset of instanceof inside vtable (int position 1, byte position 4)
@@ -557,11 +559,14 @@ public class TypeManager {
     WatCodeSyntheticFunctionName createCast() {
         return new WatCodeSyntheticFunctionName( //
                         "cast", "local.get 0 " // THIS
+                                        + "ref.is_null if local.get 0 return end " // NULL check
+                                        + "local.get 0 " // THIS
                                         + "local.get 1 " // the class index that we search
                                         + "call $.instanceof()V " // the synthetic signature of ArraySyntheticFunctionName
-                                        + "i32.eqz " //
+                                        + "if " //
-                                        + "local.get 0 " // THIS
+                                        + "  local.get 0 " // THIS
-                                        + "return " //
+                                        + "  return " //
+                                        + "end " //
                                         + "unreachable " // TODO throw a ClassCastException if exception handling is supported
                         , valueOf( "java/lang/Object" ), ValueType.i32, null, valueOf( "java/lang/Object" ) );
     }

src/de/inetsoftware/jwebassembly/text/TextModuleWriter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2017 - 2021 Volker Berlin (i-net software)
+ * Copyright 2017 - 2022 Volker Berlin (i-net software)
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -834,6 +834,9 @@ public class TextModuleWriter extends ModuleWriter {
                 }
                 name = builder.toString();
                 break;
+            case BR_ON_NULL:
+                name = "br_on_null " + data;
+                break;
             case LOOP:
                 name = "loop";
                 insetAfter++;

src/de/inetsoftware/jwebassembly/wasm/WasmBlockOperator.java

@@ -1,5 +1,5 @@
 /*
-   Copyright 2018 - 2019 Volker Berlin (i-net software)
+   Copyright 2018 - 2022 Volker Berlin (i-net software)
 
    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
@@ -32,6 +32,7 @@ public enum WasmBlockOperator {
     BR,
     BR_IF,
     BR_TABLE,
+    BR_ON_NULL,
     LOOP,
     UNREACHABLE,
     TRY,

src/de/inetsoftware/jwebassembly/watparser/WatParser.java

@@ -1,5 +1,5 @@
 /*
-   Copyright 2018 - 2021 Volker Berlin (i-net software)
+   Copyright 2018 - 2022 Volker Berlin (i-net software)
 
    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
@@ -272,6 +272,9 @@ public class WatParser extends WasmCodeBuilder {
                     case "br_if":
                         addBlockInstruction( WasmBlockOperator.BR_IF, getInt( tokens, ++i ), javaCodePos, lineNumber );
                         break;
+                    case "br_on_null":
+                        addBlockInstruction( WasmBlockOperator.BR_ON_NULL, getInt( tokens, ++i ), javaCodePos, lineNumber );
+                        break;
                     case "throw":
                         addBlockInstruction( WasmBlockOperator.THROW, null, javaCodePos, lineNumber );
                         break;

test/de/inetsoftware/jwebassembly/runtime/StructsNonGC.java

@@ -61,7 +61,9 @@ public class StructsNonGC extends AbstractBaseTest {
             addParam( list, script, "instanceof1" );
             addParam( list, script, "instanceof2" );
             addParam( list, script, "instanceof3" );
-            addParam( list, script, "cast" );
+            addParam( list, script, "instanceof4" );
+            addParam( list, script, "cast1" );
+            addParam( list, script, "cast2" );
             addParam( list, script, "objectClassName" );
             addParam( list, script, "integerClassName" );
             addParam( list, script, "classClassName" );
@@ -197,12 +199,25 @@ public class StructsNonGC extends AbstractBaseTest {
         }
 
         @Export
-        static int cast() {
+        static boolean instanceof4() {
+            Object obj = null;
+            return obj instanceof List;
+        }
+
+        @Export
+        static int cast1() {
             Object obj = new Integer(42);
             Integer val = (Integer)obj;
             return val.intValue();
         }
 
+        @Export
+        static Integer cast2() {
+            Object obj = null;
+            Integer val = (Integer)obj;
+            return val;
+        }
+
         @Export
         static DOMString objectClassName() {
             Object obj = new Object();