From 775496640cfb828d2586312702e70260ea13c3c6 Mon Sep 17 00:00:00 2001
From: Volker Berlin <volker.berlin@googlemail.com>
Date: Sun, 15 Mar 2020 15:49:52 +0100
Subject: [PATCH] add support for Class constants

---
 .../jwebassembly/module/ReplacementForClass.java    |  2 +-
 .../jwebassembly/module/TypeManager.java            |  6 ++++++
 .../jwebassembly/module/WasmCodeBuilder.java        |  7 +++++++
 .../jwebassembly/runtime/RuntimeErrors.java         | 13 -------------
 .../jwebassembly/runtime/StructsNonGC.java          |  7 +++++++
 5 files changed, 21 insertions(+), 14 deletions(-)

diff --git a/src/de/inetsoftware/jwebassembly/module/ReplacementForClass.java b/src/de/inetsoftware/jwebassembly/module/ReplacementForClass.java
index a6b4e59..a4f3042 100644
--- a/src/de/inetsoftware/jwebassembly/module/ReplacementForClass.java
+++ b/src/de/inetsoftware/jwebassembly/module/ReplacementForClass.java
@@ -81,7 +81,7 @@ class ReplacementForClass {
      * @param classIdx
      *            the id/index of the Class.
      * @return the string
-     * @see #CLASS_CONSTANT_FUNCTION
+     * @see TypeManager#getClassConstantFunction()
      */
     private static ReplacementForClass classConstant( int classIdx ) {
         ReplacementForClass clazz = getClassFromTable( classIdx );
diff --git a/src/de/inetsoftware/jwebassembly/module/TypeManager.java b/src/de/inetsoftware/jwebassembly/module/TypeManager.java
index 3d46f5b..819b767 100644
--- a/src/de/inetsoftware/jwebassembly/module/TypeManager.java
+++ b/src/de/inetsoftware/jwebassembly/module/TypeManager.java
@@ -79,6 +79,8 @@ public class TypeManager {
      */
     private static final int        VTABLE_FIRST_FUNCTION_INDEX = 3;
 
+    private static final FunctionName CLASS_CONSTANT_FUNCTION = new FunctionName( "java/lang/Class.classConstant(I)Lde/inetsoftware/jwebassembly/module/ReplacementForClass;" ); 
+
     private Map<String, StructType> structTypes = new LinkedHashMap<>();
 
     private Map<AnyType, ArrayType> arrayTypes  = new LinkedHashMap<>();
@@ -151,6 +153,10 @@ public class TypeManager {
         return offsetFunction;
     }
 
+    FunctionName getClassConstantFunction() {
+        return CLASS_CONSTANT_FUNCTION;
+    }
+
     /**
      * Get the StructType. If needed an instance is created.
      * 
diff --git a/src/de/inetsoftware/jwebassembly/module/WasmCodeBuilder.java b/src/de/inetsoftware/jwebassembly/module/WasmCodeBuilder.java
index e2cc439..2feeb2a 100644
--- a/src/de/inetsoftware/jwebassembly/module/WasmCodeBuilder.java
+++ b/src/de/inetsoftware/jwebassembly/module/WasmCodeBuilder.java
@@ -26,6 +26,7 @@ import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 
 import de.inetsoftware.classparser.ClassFile;
+import de.inetsoftware.classparser.ConstantClass;
 import de.inetsoftware.classparser.LocalVariableTable;
 import de.inetsoftware.classparser.Member;
 import de.inetsoftware.classparser.MethodInfo;
@@ -400,6 +401,12 @@ public abstract class WasmCodeBuilder {
             addCallInstruction( name, javaCodePos, lineNumber );
         } else if( value instanceof Number ) {
             instructions.add( new WasmConstInstruction( (Number)value, javaCodePos, lineNumber ) );
+        } else if( value instanceof ConstantClass ) {
+            String className = ((ConstantClass)value).getName();
+            Integer id = types.valueOf( className ).getClassIndex();
+            FunctionName name = types.getClassConstantFunction();
+            instructions.add( new WasmConstInstruction( id, ValueType.i32, javaCodePos, lineNumber ) );
+            addCallInstruction( name, javaCodePos, lineNumber );
         } else {
             //TODO There can be ConstantClass, MethodType and MethodHandle
             throw new WasmException( "Class constants are not supported. : " + value, lineNumber );
diff --git a/test/de/inetsoftware/jwebassembly/runtime/RuntimeErrors.java b/test/de/inetsoftware/jwebassembly/runtime/RuntimeErrors.java
index 4462fec..b39d37c 100644
--- a/test/de/inetsoftware/jwebassembly/runtime/RuntimeErrors.java
+++ b/test/de/inetsoftware/jwebassembly/runtime/RuntimeErrors.java
@@ -125,17 +125,4 @@ public class RuntimeErrors {
             return list.size();
         }
     }
-
-    @Test
-    public void classConatnt() throws IOException {
-        compileErrorTest( "Class constants are not supported.", ClassConstant.class );
-    }
-
-    static class ClassConstant {
-        @Export
-        static Object runnable() {
-            Class elemtentType = Integer.class;
-            return java.lang.reflect.Array.newInstance(elemtentType, 42);
-        }
-    }
 }
diff --git a/test/de/inetsoftware/jwebassembly/runtime/StructsNonGC.java b/test/de/inetsoftware/jwebassembly/runtime/StructsNonGC.java
index 8a89dc6..3910c6c 100644
--- a/test/de/inetsoftware/jwebassembly/runtime/StructsNonGC.java
+++ b/test/de/inetsoftware/jwebassembly/runtime/StructsNonGC.java
@@ -59,6 +59,7 @@ public class StructsNonGC extends AbstractBaseTest {
             addParam( list, script, "objectClassName" );
             addParam( list, script, "integerClassName" );
             addParam( list, script, "classClassName" );
+            addParam( list, script, "classConst" );
         }
         rule.setTestParameters( list );
         return list;
@@ -195,6 +196,12 @@ public class StructsNonGC extends AbstractBaseTest {
             Class clazz = obj.getClass().getClass();
             return JSObject.domString( clazz.getName() );
         }
+
+        @Export
+        static String classConst() {
+            Class clazz = Float.class;
+            return JSObject.domString( clazz.getName() );
+        }
     }
 
     interface TestDefault {