wasm gc: implement Array.getLength and Array.get

core/src/main/java/org/teavm/ast/optimization/OptimizingVisitor.java

@@ -1097,6 +1097,7 @@ class OptimizingVisitor implements StatementVisitor, ExprVisitor {
             conditionalExpr.setConsequent(firstAssignment.getRightValue());
             conditionalExpr.setAlternative(secondAssignment.getRightValue());
             conditionalExpr.setLocation(statement.getCondition().getLocation());
+            conditionalExpr.setVariableIndex(firstAssignment.getRightValue().getVariableIndex());
             AssignmentStatement assignment = new AssignmentStatement();
             assignment.setLocation(conditionalExpr.getLocation());
             VariableExpr lhs = new VariableExpr();

core/src/main/java/org/teavm/backend/wasm/generate/common/methods/BaseWasmGenerationVisitor.java

@@ -538,12 +538,16 @@ public abstract class BaseWasmGenerationVisitor implements StatementVisitor, Exp
         var elseType = typeInference.getResult();
         conditional.getElseBlock().setType(elseType);
 
-        assert thenType == elseType;
+        conditional.setType(condBlockType(thenType, elseType, expr));
-        conditional.setType(thenType);
 
         result = conditional;
     }
 
+    protected WasmType condBlockType(WasmType thenType, WasmType elseType, ConditionalExpr conditional) {
+        assert thenType == elseType;
+        return thenType;
+    }
+
     @Override
     public void visit(SequentialStatement statement) {
         for (var part : statement.getSequence()) {

core/src/main/java/org/teavm/backend/wasm/generate/gc/classes/WasmGCClassGenerator.java

@@ -44,6 +44,7 @@ import org.teavm.backend.wasm.model.WasmStorageType;
 import org.teavm.backend.wasm.model.WasmStructure;
 import org.teavm.backend.wasm.model.WasmType;
 import org.teavm.backend.wasm.model.expression.WasmArrayCopy;
+import org.teavm.backend.wasm.model.expression.WasmArrayGet;
 import org.teavm.backend.wasm.model.expression.WasmArrayLength;
 import org.teavm.backend.wasm.model.expression.WasmArrayNewDefault;
 import org.teavm.backend.wasm.model.expression.WasmCall;
@@ -71,6 +72,7 @@ import org.teavm.model.ElementModifier;
 import org.teavm.model.FieldReference;
 import org.teavm.model.MethodDescriptor;
 import org.teavm.model.MethodReference;
+import org.teavm.model.PrimitiveType;
 import org.teavm.model.ValueType;
 import org.teavm.model.analysis.ClassInitializerInfo;
 import org.teavm.model.analysis.ClassMetadataRequirements;
@@ -85,6 +87,7 @@ public class WasmGCClassGenerator implements WasmGCClassInfoProvider, WasmGCInit
             ValueType.parse(Class.class));
     private static final FieldReference FAKE_CLASS_FIELD = new FieldReference(Object.class.getName(), "class");
     private static final FieldReference FAKE_MONITOR_FIELD = new FieldReference(Object.class.getName(), "monitor");
+    private static final ValueType OBJECT_TYPE = ValueType.parse(Object.class);
 
     private final WasmModule module;
     private ClassReaderSource classSource;
@@ -119,6 +122,13 @@ public class WasmGCClassGenerator implements WasmGCClassInfoProvider, WasmGCInit
     private int classNewArrayOffset;
     private int classSupertypeFunctionOffset;
     private int virtualTableFieldOffset;
+    private int arrayLengthOffset = -1;
+    private int arrayGetOffset = -1;
+    private WasmStructure arrayVirtualTableStruct;
+    private WasmFunction arrayGetObjectFunction;
+    private WasmFunction arrayLengthObjectFunction;
+    private WasmFunctionType arrayGetType;
+    private WasmFunctionType arrayLengthType;
 
     public WasmGCClassGenerator(WasmModule module, ClassReaderSource classSource,
             WasmFunctionTypes functionTypes, TagRegistry tagRegistry,
@@ -249,10 +259,18 @@ public class WasmGCClassGenerator implements WasmGCClassInfoProvider, WasmGCInit
                     classInfo.structure = standardClasses.objectClass().structure;
                 } else {
                     var finalClassInfo = classInfo;
+                    if (type instanceof ValueType.Array) {
+                        var itemType = ((ValueType.Array) type).getItemType();
+                        if (!(itemType instanceof ValueType.Primitive) && !itemType.equals(OBJECT_TYPE)) {
+                            classInfo.structure = getClassInfo(ValueType.arrayOf(OBJECT_TYPE)).structure;
+                        }
+                    }
+                    if (classInfo.structure == null) {
                         classInfo.structure = new WasmStructure(name != null ? names.forClass(name) : null,
                                 fields -> fillFields(finalClassInfo, fields, type));
                         module.types.add(classInfo.structure);
                     }
+                }
                 if (name != null) {
                     if (!isInterface) {
                         virtualTable = virtualTables.lookup(name);
@@ -272,7 +290,7 @@ public class WasmGCClassGenerator implements WasmGCClassInfoProvider, WasmGCInit
                 if (type instanceof ValueType.Object) {
                     classStructure = initRegularClassStructure(((ValueType.Object) type).getClassName());
                 } else {
-                    classStructure = standardClasses.objectClass().getVirtualTableStructure();
+                    classStructure = getArrayVirtualTableStructure();
                 }
             } else {
                 classStructure = standardClasses.classClass().getStructure();
@@ -431,10 +449,10 @@ public class WasmGCClassGenerator implements WasmGCClassInfoProvider, WasmGCInit
         }
     }
 
-    private void fillArrayVirtualTableMethods(List<WasmExpression> target, WasmGlobal global,
+    private void fillArrayVirtualTableMethods(ValueType type, List<WasmExpression> target, WasmGlobal global,
             WasmStructure objectStructure) {
         var virtualTable = virtualTables.lookup("java.lang.Object");
-        var structure = standardClasses.objectClass().getVirtualTableStructure();
+        var structure = getArrayVirtualTableStructure();
 
         for (var entry : virtualTable.getEntries()) {
             if (entry.getMethod().getName().equals("clone")) {
@@ -447,6 +465,157 @@ public class WasmGCClassGenerator implements WasmGCClassInfoProvider, WasmGCInit
                 fillVirtualTableEntry(target, global, structure, virtualTable, entry);
             }
         }
+
+        var itemType = ((ValueType.Array) type).getItemType();
+        var info = metadataRequirements.getInfo(type);
+        if (info.arrayLength()) {
+            var lengthFunction = getArrayLengthFunction(objectStructure);
+            target.add(new WasmStructSet(structure, new WasmGetGlobal(global), arrayLengthOffset,
+                    new WasmFunctionReference(lengthFunction)));
+        }
+        if (info.arrayGet()) {
+            var getFunction = getArrayGetFunction(itemType);
+            target.add(new WasmStructSet(structure, new WasmGetGlobal(global), arrayGetOffset,
+                    new WasmFunctionReference(getFunction)));
+        }
+    }
+
+
+    private WasmFunction getArrayLengthFunction(WasmStructure objectStructure) {
+        var arrayTypeRef = (WasmType.CompositeReference) objectStructure.getFields().get(ARRAY_DATA_FIELD_OFFSET)
+                .getUnpackedType();
+        var arrayType = (WasmArray) arrayTypeRef.composite;
+        var elementType = arrayType.getElementType().asUnpackedType();
+        if (elementType instanceof WasmType.Reference) {
+            if (arrayLengthObjectFunction == null) {
+                arrayLengthObjectFunction = getArrayLengthFunction(objectStructure, arrayType);
+            }
+            return arrayLengthObjectFunction;
+        }
+        return getArrayLengthFunction(objectStructure, arrayType);
+    }
+
+    private WasmFunction getArrayLengthFunction(WasmStructure objectStructure, WasmArray arrayType) {
+        var function = new WasmFunction(functionTypes.of(WasmType.INT32, standardClasses.objectClass().getType()));
+        function.setReferenced(true);
+        module.functions.add(function);
+
+        var objectLocal = new WasmLocal(standardClasses.objectClass().getType());
+        function.add(objectLocal);
+
+        var castObject = new WasmCast(new WasmGetLocal(objectLocal), objectStructure.getReference());
+        var arrayField = new WasmStructGet(objectStructure, castObject, ARRAY_DATA_FIELD_OFFSET);
+        var result = new WasmArrayLength(arrayField);
+        function.getBody().add(new WasmReturn(result));
+        return function;
+    }
+
+    private WasmFunction getArrayGetFunction(ValueType itemType) {
+        if (itemType instanceof ValueType.Primitive) {
+            return generateArrayGetPrimitiveFunction(((ValueType.Primitive) itemType).getKind());
+        }
+        return getArrayGetObjectFunction();
+    }
+
+    private WasmFunction getArrayGetObjectFunction() {
+        if (arrayGetObjectFunction == null) {
+            arrayGetObjectFunction = new WasmFunction(getArrayGetType());
+            module.functions.add(arrayGetObjectFunction);
+            arrayGetObjectFunction.setReferenced(true);
+
+            var arrayStruct = getClassInfo(ValueType.arrayOf(OBJECT_TYPE)).structure;
+            var arrayDataTypeRef = (WasmType.CompositeReference) arrayStruct.getFields()
+                    .get(ARRAY_DATA_FIELD_OFFSET).getUnpackedType();
+            var arrayDataType = (WasmArray) arrayDataTypeRef.composite;
+            var objectLocal = new WasmLocal(standardClasses.objectClass().getType());
+            var indexLocal = new WasmLocal(WasmType.INT32);
+            arrayGetObjectFunction.add(objectLocal);
+            arrayGetObjectFunction.add(indexLocal);
+
+            var array = new WasmCast(new WasmGetLocal(objectLocal), arrayStruct.getReference());
+            var arrayData = new WasmStructGet(arrayStruct, array, ARRAY_DATA_FIELD_OFFSET);
+            var result = new WasmArrayGet(arrayDataType, arrayData, new WasmGetLocal(indexLocal));
+            arrayGetObjectFunction.getBody().add(new WasmReturn(result));
+        }
+        return arrayGetObjectFunction;
+    }
+
+    private WasmFunction generateArrayGetPrimitiveFunction(PrimitiveType type) {
+        var function = new WasmFunction(getArrayGetType());
+        module.functions.add(function);
+        function.setReferenced(true);
+
+        var arrayStruct = getClassInfo(ValueType.arrayOf(ValueType.primitive(type))).structure;
+        var arrayDataTypeRef = (WasmType.CompositeReference) arrayStruct.getFields()
+                .get(ARRAY_DATA_FIELD_OFFSET).getUnpackedType();
+        var arrayDataType = (WasmArray) arrayDataTypeRef.composite;
+        var objectLocal = new WasmLocal(standardClasses.objectClass().getType());
+        var indexLocal = new WasmLocal(WasmType.INT32);
+        function.add(objectLocal);
+        function.add(indexLocal);
+
+        var array = new WasmCast(new WasmGetLocal(objectLocal), arrayStruct.getReference());
+        var arrayData = new WasmStructGet(arrayStruct, array, ARRAY_DATA_FIELD_OFFSET);
+        var result = new WasmArrayGet(arrayDataType, arrayData, new WasmGetLocal(indexLocal));
+        Class<?> primitiveType;
+        Class<?> wrapperType;
+        switch (type) {
+            case BOOLEAN:
+                primitiveType = boolean.class;
+                wrapperType = Boolean.class;
+                break;
+            case BYTE:
+                primitiveType = byte.class;
+                wrapperType = Byte.class;
+                break;
+            case SHORT:
+                primitiveType = short.class;
+                wrapperType = Short.class;
+                break;
+            case CHARACTER:
+                primitiveType = char.class;
+                wrapperType = Character.class;
+                break;
+            case INTEGER:
+                primitiveType = int.class;
+                wrapperType = Integer.class;
+                break;
+            case LONG:
+                primitiveType = long.class;
+                wrapperType = Long.class;
+                break;
+            case FLOAT:
+                primitiveType = float.class;
+                wrapperType = Float.class;
+                break;
+            case DOUBLE:
+                primitiveType = double.class;
+                wrapperType = Double.class;
+                break;
+            default:
+                throw new IllegalArgumentException();
+        }
+        var method = new MethodReference(wrapperType, "valueOf", primitiveType, wrapperType);
+        var wrapFunction = functionProvider.forStaticMethod(method);
+        var castResult = new WasmCall(wrapFunction, result);
+        function.getBody().add(new WasmReturn(castResult));
+
+        return function;
+    }
+
+    private WasmFunctionType getArrayGetType() {
+        if (arrayGetType == null) {
+            arrayGetType = functionTypes.of(standardClasses.objectClass().getType(),
+                    standardClasses.objectClass().getType(), WasmType.INT32);
+        }
+        return arrayGetType;
+    }
+
+    private WasmFunctionType getArrayLengthType() {
+        if (arrayLengthType == null) {
+            arrayLengthType = functionTypes.of(WasmType.INT32, standardClasses.objectClass().getType());
+        }
+        return arrayLengthType;
     }
 
     private void fillVirtualTableEntry(List<WasmExpression> target, WasmGlobal global,
@@ -556,6 +725,40 @@ public class WasmGCClassGenerator implements WasmGCClassInfoProvider, WasmGCInit
         }
     }
 
+    @Override
+    public WasmStructure getArrayVirtualTableStructure() {
+        if (arrayVirtualTableStruct == null) {
+            arrayVirtualTableStruct = new WasmStructure(null);
+            arrayVirtualTableStruct.setSupertype(standardClasses.objectClass().getVirtualTableStructure());
+            module.types.add(arrayVirtualTableStruct);
+            addSystemFields(arrayVirtualTableStruct.getFields());
+            fillSimpleClassFields(arrayVirtualTableStruct.getFields(), "java.lang.Class");
+            addVirtualTableFields(arrayVirtualTableStruct, virtualTables.lookup("java.lang.Object"));
+
+            if (metadataRequirements.hasArrayLength()) {
+                arrayLengthOffset = arrayVirtualTableStruct.getFields().size();
+                var arrayLengthType = getArrayLengthType();
+                arrayVirtualTableStruct.getFields().add(new WasmField(arrayLengthType.getReference().asStorage()));
+            }
+            if (metadataRequirements.hasArrayGet()) {
+                arrayGetOffset = arrayVirtualTableStruct.getFields().size();
+                var arrayGetType = getArrayGetType();
+                arrayVirtualTableStruct.getFields().add(new WasmField(arrayGetType.getReference().asStorage()));
+            }
+        }
+        return arrayVirtualTableStruct;
+    }
+
+    @Override
+    public int getArrayLengthOffset() {
+        return arrayLengthOffset;
+    }
+
+    @Override
+    public int getArrayGetOffset() {
+        return arrayGetOffset;
+    }
+
     private void initArrayClass(WasmGCClassInfo classInfo, ValueType.Array type) {
         classInfo.initializer = target -> {
             var itemTypeInfo = getClassInfo(type.getItemType());
@@ -564,7 +767,7 @@ public class WasmGCClassGenerator implements WasmGCClassInfoProvider, WasmGCInit
                     new WasmGetGlobal(classInfo.pointer),
                     new WasmGetGlobal(itemTypeInfo.pointer)
             ));
-            fillArrayVirtualTableMethods(target, classInfo.pointer, classInfo.structure);
+            fillArrayVirtualTableMethods(classInfo.getValueType(), target, classInfo.pointer, classInfo.structure);
         };
     }
 
@@ -744,12 +947,11 @@ public class WasmGCClassGenerator implements WasmGCClassInfoProvider, WasmGCInit
                     throw new IllegalArgumentException();
             }
         } else {
-            wasmElementType = WasmType.Reference.STRUCT.asStorage();
+            wasmElementType = standardClasses.objectClass().getType().asStorage();
         }
         var wasmArray = new WasmArray(null, wasmElementType);
         module.types.add(wasmArray);
         classInfo.structure.getFields().add(new WasmField(wasmArray.getReference().asStorage(), "data"));
-        classInfo.array = wasmArray;
     }
 
     private WasmFunction getCreatePrimitiveClassFunction() {

core/src/main/java/org/teavm/backend/wasm/generate/gc/classes/WasmGCClassInfo.java

@@ -27,7 +27,6 @@ import org.teavm.model.ValueType;
 public class WasmGCClassInfo {
     private ValueType valueType;
     WasmStructure structure;
-    WasmArray array;
     boolean hasOwnVirtualTable;
     WasmStructure virtualTableStructure;
     WasmGlobal pointer;
@@ -47,8 +46,9 @@ public class WasmGCClassInfo {
     }
 
     public WasmArray getArray() {
-        structure.init();
+        var field = structure.getFields().get(WasmGCClassInfoProvider.ARRAY_DATA_FIELD_OFFSET);
-        return array;
+        var type = (WasmType.CompositeReference) field.getUnpackedType();
+        return (WasmArray) type.composite;
     }
 
     public WasmStructure getVirtualTableStructure() {

core/src/main/java/org/teavm/backend/wasm/generate/gc/classes/WasmGCClassInfoProvider.java

@@ -16,6 +16,7 @@
 package org.teavm.backend.wasm.generate.gc.classes;
 
 import org.teavm.backend.wasm.model.WasmGlobal;
+import org.teavm.backend.wasm.model.WasmStructure;
 import org.teavm.model.FieldReference;
 import org.teavm.model.ValueType;
 
@@ -27,6 +28,8 @@ public interface WasmGCClassInfoProvider {
 
     WasmGCClassInfo getClassInfo(ValueType type);
 
+    WasmStructure getArrayVirtualTableStructure();
+
     int getFieldIndex(FieldReference fieldRef);
 
     WasmGlobal getStaticFieldLocation(FieldReference fieldRef);
@@ -41,6 +44,10 @@ public interface WasmGCClassInfoProvider {
 
     int getClassNameOffset();
 
+    int getArrayGetOffset();
+
+    int getArrayLengthOffset();
+
     default WasmGCClassInfo getClassInfo(String name) {
         return getClassInfo(ValueType.object(name));
     }

core/src/main/java/org/teavm/backend/wasm/generate/gc/methods/WasmGCGenerationVisitor.java

@@ -18,6 +18,7 @@ package org.teavm.backend.wasm.generate.gc.methods;
 import java.util.List;
 import org.teavm.ast.ArrayType;
 import org.teavm.ast.BinaryExpr;
+import org.teavm.ast.ConditionalExpr;
 import org.teavm.ast.Expr;
 import org.teavm.ast.InvocationExpr;
 import org.teavm.ast.InvocationType;
@@ -26,6 +27,7 @@ import org.teavm.ast.SubscriptExpr;
 import org.teavm.backend.wasm.BaseWasmFunctionRepository;
 import org.teavm.backend.wasm.WasmFunctionTypes;
 import org.teavm.backend.wasm.gc.PreciseTypeInference;
+import org.teavm.backend.wasm.generate.ExpressionCache;
 import org.teavm.backend.wasm.generate.TemporaryVariablePool;
 import org.teavm.backend.wasm.generate.common.methods.BaseWasmGenerationVisitor;
 import org.teavm.backend.wasm.generate.gc.classes.WasmGCClassInfoProvider;
@@ -533,6 +535,24 @@ public class WasmGCGenerationVisitor extends BaseWasmGenerationVisitor {
         }
     }
 
+    @Override
+    protected WasmType condBlockType(WasmType thenType, WasmType elseType, ConditionalExpr conditional) {
+        if (conditional.getVariableIndex() >= 0) {
+            var javaType = types.typeOf(conditional.getVariableIndex());
+            if (javaType != null) {
+                return mapType(javaType.valueType);
+            }
+        }
+        if (conditional.getConsequent().getVariableIndex() >= 0
+                && conditional.getConsequent().getVariableIndex() == conditional.getAlternative().getVariableIndex()) {
+            var javaType = types.typeOf(conditional.getConsequent().getVariableIndex());
+            if (javaType != null) {
+                return mapType(javaType.valueType);
+            }
+        }
+        return super.condBlockType(thenType, elseType, conditional);
+    }
+
     private class SimpleCallSite extends CallSiteIdentifier {
         @Override
         public void generateRegister(List<WasmExpression> consumer, TextLocation location) {
@@ -593,5 +613,10 @@ public class WasmGCGenerationVisitor extends BaseWasmGenerationVisitor {
         public TemporaryVariablePool tempVars() {
             return tempVars;
         }
+
+        @Override
+        public ExpressionCache exprCache() {
+            return exprCache;
+        }
     };
 }

core/src/main/java/org/teavm/backend/wasm/intrinsics/gc/ArrayIntrinsic.java

@@ -0,0 +1,74 @@
+/*
+ *  Copyright 2024 Alexey Andreev.
+ *
+ *  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.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package org.teavm.backend.wasm.intrinsics.gc;
+
+import org.teavm.ast.InvocationExpr;
+import org.teavm.backend.wasm.generate.gc.classes.WasmGCClassInfoProvider;
+import org.teavm.backend.wasm.model.WasmFunctionType;
+import org.teavm.backend.wasm.model.WasmType;
+import org.teavm.backend.wasm.model.expression.WasmBlock;
+import org.teavm.backend.wasm.model.expression.WasmCallReference;
+import org.teavm.backend.wasm.model.expression.WasmCast;
+import org.teavm.backend.wasm.model.expression.WasmExpression;
+import org.teavm.backend.wasm.model.expression.WasmStructGet;
+
+public class ArrayIntrinsic implements WasmGCIntrinsic {
+    @Override
+    public WasmExpression apply(InvocationExpr invocation, WasmGCIntrinsicContext context) {
+        switch (invocation.getMethod().getName()) {
+            case "getLength":
+                return arrayLength(invocation, context);
+            case "getImpl":
+                return arrayGet(invocation, context);
+            default:
+                throw new IllegalArgumentException("Unknown method: " + invocation.getMethod());
+        }
+    }
+
+    private WasmExpression arrayLength(InvocationExpr invocation, WasmGCIntrinsicContext context) {
+        return arrayVirtualCall(invocation, context, context.classInfoProvider().getArrayLengthOffset());
+    }
+
+    private WasmExpression arrayGet(InvocationExpr invocation, WasmGCIntrinsicContext context) {
+        return arrayVirtualCall(invocation, context, context.classInfoProvider().getArrayGetOffset());
+    }
+
+    private WasmExpression arrayVirtualCall(InvocationExpr invocation, WasmGCIntrinsicContext context,
+            int offset) {
+        var objectStruct = context.classInfoProvider().getClassInfo("java.lang.Object").getStructure();
+        var vtStruct = context.classInfoProvider().getArrayVirtualTableStructure();
+        var type = (WasmType.CompositeReference) vtStruct.getFields().get(offset).getUnpackedType();
+        var functionType = (WasmFunctionType) type.composite;
+        var block = new WasmBlock(false);
+        block.setType(functionType.getReturnType());
+
+        var originalObject = context.generate(invocation.getArguments().get(0));
+        var object = context.exprCache().create(originalObject, objectStruct.getReference(),
+                invocation.getLocation(), block.getBody());
+        var classRef = new WasmStructGet(objectStruct, object.expr(), WasmGCClassInfoProvider.CLASS_FIELD_OFFSET);
+        var vt = new WasmCast(classRef, vtStruct.getReference());
+        var function = new WasmStructGet(vtStruct, vt, offset);
+        var call = new WasmCallReference(function, functionType);
+        call.getArguments().add(object.expr());
+        for (var i = 1; i < invocation.getArguments().size(); ++i) {
+            call.getArguments().add(context.generate(invocation.getArguments().get(i)));
+        }
+        block.getBody().add(call);
+
+        object.release();
+        return block;
+    }
+}

core/src/main/java/org/teavm/backend/wasm/intrinsics/gc/WasmGCIntrinsicContext.java

@@ -19,6 +19,7 @@ import org.teavm.ast.Expr;
 import org.teavm.backend.wasm.BaseWasmFunctionRepository;
 import org.teavm.backend.wasm.WasmFunctionTypes;
 import org.teavm.backend.wasm.gc.PreciseTypeInference;
+import org.teavm.backend.wasm.generate.ExpressionCache;
 import org.teavm.backend.wasm.generate.TemporaryVariablePool;
 import org.teavm.backend.wasm.generate.gc.classes.WasmGCClassInfoProvider;
 import org.teavm.backend.wasm.generate.gc.classes.WasmGCTypeMapper;
@@ -44,4 +45,6 @@ public interface WasmGCIntrinsicContext {
     WasmGCClassInfoProvider classInfoProvider();
 
     TemporaryVariablePool tempVars();
+
+    ExpressionCache exprCache();
 }

core/src/main/java/org/teavm/backend/wasm/intrinsics/gc/WasmGCIntrinsics.java

@@ -15,6 +15,7 @@
  */
 package org.teavm.backend.wasm.intrinsics.gc;
 
+import java.lang.reflect.Array;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -33,6 +34,7 @@ public class WasmGCIntrinsics implements WasmGCIntrinsicProvider {
         fillClass();
         fillSystem();
         fillLongAndInteger();
+        fillArray();
     }
 
     private void fillWasmRuntime() {
@@ -91,6 +93,12 @@ public class WasmGCIntrinsics implements WasmGCIntrinsicProvider {
                 intrinsic);
     }
 
+    private void fillArray() {
+        var intrinsic = new ArrayIntrinsic();
+        intrinsics.put(new MethodReference(Array.class, "getLength", Object.class, int.class), intrinsic);
+        intrinsics.put(new MethodReference(Array.class, "getImpl", Object.class, int.class, Object.class), intrinsic);
+    }
+
     @Override
     public WasmGCIntrinsic get(MethodReference method) {
         return intrinsics.get(method);

core/src/main/java/org/teavm/model/analysis/ClassMetadataRequirements.java

@@ -37,8 +37,14 @@ public class ClassMetadataRequirements {
             "getEnclosingClass", Class.class);
     private static final MethodReference NEW_ARRAY = new MethodReference(Array.class,
             "newInstance", Class.class, int.class, Object.class);
+    private static final MethodReference ARRAY_GET = new MethodReference(Array.class,
+            "get", Object.class, int.class, Object.class);
+    private static final MethodReference ARRAY_LENGTH = new MethodReference(Array.class,
+            "getLength", Object.class, int.class);
     private static final ClassInfo EMPTY_INFO = new ClassInfo();
     private Map<ValueType, ClassInfo> requirements = new HashMap<>();
+    private boolean hasArrayGet;
+    private boolean hasArrayLength;
 
     public ClassMetadataRequirements(DependencyInfo dependencyInfo) {
         MethodDependencyInfo getNameMethod = dependencyInfo.getMethod(GET_NAME_METHOD);
@@ -96,6 +102,24 @@ public class ClassMetadataRequirements {
                 requirements.computeIfAbsent(decodeType(className), k -> new ClassInfo()).newArray = true;
             }
         }
+
+        var arrayGet = dependencyInfo.getMethod(ARRAY_GET);
+        if (arrayGet != null) {
+            hasArrayGet = arrayGet.isUsed();
+            var classNames = arrayGet.getVariable(1).getTypes();
+            for (var className : classNames) {
+                requirements.computeIfAbsent(decodeType(className), k -> new ClassInfo()).arrayGet = true;
+            }
+        }
+
+        var arrayLength = dependencyInfo.getMethod(ARRAY_LENGTH);
+        if (arrayLength != null) {
+            hasArrayLength = arrayLength.isUsed();
+            var classNames = arrayLength.getVariable(1).getTypes();
+            for (var className : classNames) {
+                requirements.computeIfAbsent(decodeType(className), k -> new ClassInfo()).arrayLength = true;
+            }
+        }
     }
 
     public Info getInfo(String className) {
@@ -110,6 +134,14 @@ public class ClassMetadataRequirements {
         return result;
     }
 
+    public boolean hasArrayGet() {
+        return hasArrayGet;
+    }
+
+    public boolean hasArrayLength() {
+        return hasArrayLength;
+    }
+
     private void addClassesRequiringName(Map<ValueType, ClassInfo> target, String[] source) {
         for (String typeName : source) {
             target.computeIfAbsent(decodeType(typeName), k -> new ClassInfo()).name = true;
@@ -134,6 +166,8 @@ public class ClassMetadataRequirements {
         boolean superclass;
         boolean isAssignable;
         boolean newArray;
+        boolean arrayLength;
+        boolean arrayGet;
 
         @Override
         public boolean name() {
@@ -169,6 +203,16 @@ public class ClassMetadataRequirements {
         public boolean newArray() {
             return newArray;
         }
+
+        @Override
+        public boolean arrayLength() {
+            return arrayLength;
+        }
+
+        @Override
+        public boolean arrayGet() {
+            return arrayGet;
+        }
     }
 
     public interface Info {
@@ -185,5 +229,9 @@ public class ClassMetadataRequirements {
         boolean isAssignable();
 
         boolean newArray();
+
+        boolean arrayLength();
+
+        boolean arrayGet();
     }
 }

tests/src/test/java/org/teavm/classlib/java/lang/reflect/ArrayTest.java

@@ -18,6 +18,8 @@ package org.teavm.classlib.java.lang.reflect;
 import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
 import java.lang.reflect.Array;
+import java.util.ArrayList;
+import java.util.List;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.teavm.junit.EachTestCompiledSeparately;
@@ -43,7 +45,24 @@ public class ArrayTest {
     }
 
     @Test
-    @SkipPlatform({TestPlatform.C, TestPlatform.WEBASSEMBLY, TestPlatform.WASI})
+    public void getWorks() {
+        var intArray = new int[] { 23, 42 };
+        var stringArray = new String[] { "asd", "qwe" };
+        var list = new ArrayList<>();
+        copyToList(list, intArray);
+        copyToList(list, stringArray);
+        assertEquals(List.of(23, 42, "asd", "qwe"), list);
+    }
+
+    private void copyToList(List<Object> target, Object array) {
+        var length = Array.getLength(array);
+        for (var i = 0; i < length; ++i) {
+            target.add(Array.get(array, i));
+        }
+    }
+
+    @Test
+    @SkipPlatform({TestPlatform.C, TestPlatform.WEBASSEMBLY, TestPlatform.WASI, TestPlatform.WEBASSEMBLY_GC})
     public void setWorks() {
         Object array = Array.newInstance(String.class, 2);
         Array.set(array, 0, "foo");
@@ -52,7 +71,7 @@ public class ArrayTest {
     }
 
     @Test
-    @SkipPlatform({TestPlatform.C, TestPlatform.WEBASSEMBLY, TestPlatform.WASI})
+    @SkipPlatform({TestPlatform.C, TestPlatform.WEBASSEMBLY, TestPlatform.WASI, TestPlatform.WEBASSEMBLY_GC})
     public void setPrimitiveWorks() {
         Object array = Array.newInstance(int.class, 2);
         Array.set(array, 0, 23);