Merge branch 'wasm-gc-linear-memory' into eagler-r1

core/src/main/java/org/teavm/backend/wasm/WasmGCTarget.java

@@ -33,6 +33,7 @@ import org.teavm.backend.wasm.gc.TeaVMWasmGCHost;
 import org.teavm.backend.wasm.gc.WasmGCClassConsumer;
 import org.teavm.backend.wasm.gc.WasmGCClassConsumerContext;
 import org.teavm.backend.wasm.gc.WasmGCDependencies;
+import org.teavm.backend.wasm.generate.gc.LaxMallocInitializerContributor;
 import org.teavm.backend.wasm.generate.gc.WasmGCDeclarationsGenerator;
 import org.teavm.backend.wasm.generate.gc.WasmGCNameProvider;
 import org.teavm.backend.wasm.generate.gc.classes.WasmGCCustomTypeMapperFactory;
@@ -47,6 +48,7 @@ import org.teavm.backend.wasm.intrinsics.gc.WasmGCIntrinsics;
 import org.teavm.backend.wasm.model.WasmCustomSection;
 import org.teavm.backend.wasm.model.WasmFunction;
 import org.teavm.backend.wasm.model.WasmLocal;
+import org.teavm.backend.wasm.model.WasmMemorySegment;
 import org.teavm.backend.wasm.model.WasmModule;
 import org.teavm.backend.wasm.model.WasmTag;
 import org.teavm.backend.wasm.model.WasmType;
@@ -72,10 +74,13 @@ import org.teavm.model.ListableClassHolderSource;
 import org.teavm.model.MethodReader;
 import org.teavm.model.MethodReference;
 import org.teavm.model.Program;
+import org.teavm.model.lowlevel.Characteristics;
+import org.teavm.model.lowlevel.LowLevelNullCheckFilter;
 import org.teavm.model.transformation.BoundCheckInsertion;
 import org.teavm.model.transformation.NullCheckFilter;
 import org.teavm.model.transformation.NullCheckInsertion;
 import org.teavm.model.util.VariableCategoryProvider;
+import org.teavm.runtime.LaxMalloc;
 import org.teavm.vm.BuildTarget;
 import org.teavm.vm.TeaVMTarget;
 import org.teavm.vm.TeaVMTargetController;
@@ -83,7 +88,8 @@ import org.teavm.vm.spi.TeaVMHostExtension;
 
 public class WasmGCTarget implements TeaVMTarget, TeaVMWasmGCHost {
     private TeaVMTargetController controller;
-    private NullCheckInsertion nullCheckInsertion = new NullCheckInsertion(NullCheckFilter.EMPTY);
+    private Characteristics characteristics;
+    private NullCheckInsertion nullCheckInsertion;
     private BoundCheckInsertion boundCheckInsertion = new BoundCheckInsertion();
     private boolean strict;
     private boolean obfuscated;
@@ -99,6 +105,9 @@ public class WasmGCTarget implements TeaVMTarget, TeaVMWasmGCHost {
     private List<WasmGCCustomGeneratorFactory> customGeneratorFactories = new ArrayList<>();
     private EntryPointTransformation entryPointTransformation = new EntryPointTransformation();
     private List<WasmGCClassConsumer> classConsumers = new ArrayList<>();
+    private boolean enableDirectMallocSupport;
+    private int directMallocMinHeapSize = 0x10000;
+    private int directMallocMaxHeapSize = 0x10000000;
 
     public void setObfuscated(boolean obfuscated) {
         this.obfuscated = obfuscated;
@@ -128,6 +137,18 @@ public class WasmGCTarget implements TeaVMTarget, TeaVMWasmGCHost {
         this.sourceMapLocation = sourceMapLocation;
     }
 
+    public void setEnableDirectMallocSupport(boolean enable) {
+        this.enableDirectMallocSupport = enable;
+    }
+
+    public void setDirectMallocMinHeapSize(int minHeapSize) {
+        this.directMallocMinHeapSize = WasmRuntime.align(minHeapSize, WasmHeap.PAGE_SIZE);
+    }
+
+    public void setDirectMallocMaxHeapSize(int maxHeapSize) {
+        this.directMallocMaxHeapSize = WasmRuntime.align(maxHeapSize, WasmHeap.PAGE_SIZE);
+    }
+
     @Override
     public void addIntrinsicFactory(WasmGCIntrinsicFactory intrinsicFactory) {
         intrinsicFactories.add(intrinsicFactory);
@@ -161,6 +182,8 @@ public class WasmGCTarget implements TeaVMTarget, TeaVMWasmGCHost {
     @Override
     public void setController(TeaVMTargetController controller) {
         this.controller = controller;
+        characteristics = new Characteristics(controller.getUnprocessedClassSource());
+        nullCheckInsertion = new NullCheckInsertion(new LowLevelNullCheckFilter(characteristics));
     }
 
     @Override
@@ -194,6 +217,9 @@ public class WasmGCTarget implements TeaVMTarget, TeaVMWasmGCHost {
         var deps = new WasmGCDependencies(dependencyAnalyzer);
         deps.contribute();
         deps.contributeStandardExports();
+        if (enableDirectMallocSupport) {
+            deps.contributeDirectMalloc();
+        }
     }
 
     @Override
@@ -246,6 +272,7 @@ public class WasmGCTarget implements TeaVMTarget, TeaVMWasmGCHost {
                 controller.getClassInitializerInfo(),
                 controller.getDependencyInfo(),
                 controller.getDiagnostics(),
+                characteristics,
                 customGenerators,
                 intrinsics,
                 customTypeMapperFactories,
@@ -282,9 +309,27 @@ public class WasmGCTarget implements TeaVMTarget, TeaVMWasmGCHost {
             refQueueSupplyFunction.setExportName("teavm.reportGarbageCollectedValue");
         }
 
+        if(enableDirectMallocSupport) {
+            var laxMallocClinitRef = new MethodReference(LaxMalloc.class, "<clinit>", void.class);
+            if (controller.getDependencyInfo().getMethod(laxMallocClinitRef) != null) {
+                var laxMallocClinit = declarationsGenerator.functions().forStaticMethod(laxMallocClinitRef);
+                declarationsGenerator.addEarlyInitializerContributor(new LaxMallocInitializerContributor(laxMallocClinit));
+            }
+        }
+
         moduleGenerator.generate();
         customGenerators.contributeToModule(module);
         generateExceptionExports(declarationsGenerator);
+        if (enableDirectMallocSupport) {
+            var heapSegmentStart = 0;
+            if (!module.getSegments().isEmpty()) {
+                var lastSegment = module.getSegments().get(module.getSegments().size() - 1);
+                heapSegmentStart = WasmRuntime.align(lastSegment.getOffset()
+                        + lastSegment.getLength(), WasmHeap.PAGE_SIZE);
+            }
+            intrinsics.setupLaxMallocHeap(heapSegmentStart, heapSegmentStart + directMallocMinHeapSize,
+                    heapSegmentStart + directMallocMaxHeapSize);
+        }
         adjustModuleMemory(module);
 
         emitWasmFile(module, buildTarget, outputName, debugInfoBuilder);
@@ -390,9 +435,16 @@ public class WasmGCTarget implements TeaVMTarget, TeaVMWasmGCHost {
             return;
         }
 
-        var pages = (memorySize - 1) / WasmHeap.PAGE_SIZE + 1;
+        if (enableDirectMallocSupport) {
-        module.setMinMemorySize(pages);
+            var minPages = (memorySize - 1) / WasmHeap.PAGE_SIZE + 1;
-        module.setMaxMemorySize(pages);
+            var maxPages = minPages + (directMallocMaxHeapSize - 1) / WasmHeap.PAGE_SIZE + 1;
+            module.setMinMemorySize(minPages);
+            module.setMaxMemorySize(maxPages);
+        } else {
+            var pages = (memorySize - 1) / WasmHeap.PAGE_SIZE + 1;
+            module.setMinMemorySize(pages);
+            module.setMaxMemorySize(pages);
+        }
     }
 
     private void emitWasmFile(WasmModule module, BuildTarget buildTarget, String outputName,

core/src/main/java/org/teavm/backend/wasm/gc/WasmGCDependencies.java

@@ -22,7 +22,9 @@ import org.teavm.backend.wasm.runtime.gc.WasmGCSupport;
 import org.teavm.dependency.AbstractDependencyListener;
 import org.teavm.dependency.DependencyAgent;
 import org.teavm.dependency.DependencyAnalyzer;
+import org.teavm.interop.Address;
 import org.teavm.model.MethodReference;
+import org.teavm.runtime.LaxMalloc;
 
 public class WasmGCDependencies {
     private DependencyAnalyzer analyzer;
@@ -127,4 +129,11 @@ public class WasmGCDependencies {
     private void contributeString() {
         analyzer.addDependencyListener(new StringInternDependencySupport());
     }
+
+    public void contributeDirectMalloc() {
+        analyzer.linkMethod(new MethodReference(LaxMalloc.class, "<clinit>", void.class)).use();
+        analyzer.linkMethod(new MethodReference(LaxMalloc.class, "laxMalloc", int.class, Address.class)).use();
+        analyzer.linkMethod(new MethodReference(LaxMalloc.class, "laxCalloc", int.class, Address.class)).use();
+        analyzer.linkMethod(new MethodReference(LaxMalloc.class, "laxFree", Address.class, void.class)).use();
+    }
 }

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

@@ -0,0 +1,38 @@
+/*
+ *  Copyright 2024 lax1dude.
+ *
+ *  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.generate.gc;
+
+import org.teavm.backend.wasm.model.WasmFunction;
+import org.teavm.backend.wasm.model.expression.WasmCall;
+
+public class LaxMallocInitializerContributor implements WasmGCInitializerContributor {
+
+    private final WasmFunction clinit;
+
+    public LaxMallocInitializerContributor(WasmFunction clinit) {
+        this.clinit = clinit;
+    }
+
+    @Override
+    public void contributeToInitializerDefinitions(WasmFunction function) {
+    }
+
+    @Override
+    public void contributeToInitializer(WasmFunction function) {
+        function.getBody().add(new WasmCall(clinit));
+    }
+
+}

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

@@ -44,6 +44,7 @@ import org.teavm.model.analysis.ClassInitializerInfo;
 import org.teavm.model.analysis.ClassMetadataRequirements;
 import org.teavm.model.classes.TagRegistry;
 import org.teavm.model.classes.VirtualTableBuilder;
+import org.teavm.model.lowlevel.Characteristics;
 
 public class WasmGCDeclarationsGenerator {
     public final ClassHierarchy hierarchy;
@@ -61,6 +62,7 @@ public class WasmGCDeclarationsGenerator {
             ClassInitializerInfo classInitializerInfo,
             DependencyInfo dependencyInfo,
             Diagnostics diagnostics,
+            Characteristics characteristics,
             WasmGCCustomGeneratorProvider customGenerators,
             WasmGCIntrinsicProvider intrinsics,
             List<WasmGCCustomTypeMapperFactory> customTypeMapperFactories,
@@ -83,6 +85,7 @@ public class WasmGCDeclarationsGenerator {
                 functionTypes,
                 names,
                 diagnostics,
+                characteristics,
                 customGenerators,
                 intrinsics,
                 strict,
@@ -178,4 +181,8 @@ public class WasmGCDeclarationsGenerator {
     public void addToInitializer(Consumer<WasmFunction> contributor) {
         methodGenerator.getGenerationContext().addToInitializer(contributor);
     }
+
+    public void addEarlyInitializerContributor(WasmGCInitializerContributor contributor) {
+        initializerContributors.add(contributor);
+    }
 }

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

@@ -24,6 +24,7 @@ import org.teavm.backend.wasm.model.WasmModule;
 import org.teavm.backend.wasm.model.WasmPackedType;
 import org.teavm.backend.wasm.model.WasmStorageType;
 import org.teavm.backend.wasm.model.WasmType;
+import org.teavm.interop.Address;
 import org.teavm.model.ClassReaderSource;
 import org.teavm.model.MethodDescriptor;
 import org.teavm.model.ValueType;
@@ -127,12 +128,17 @@ public class WasmGCTypeMapper {
                 }
             }
             if (result == null) {
-                var cls = classes.get(className);
+                if (className.equals(Address.class.getName())) {
-                if (cls == null) {
+                    result = WasmType.INT32;
-                    className = "java.lang.Object";
+                    typeCache.put(className, result);
+                } else {
+                    var cls = classes.get(className);
+                    if (cls == null) {
+                        className = "java.lang.Object";
+                    }
+                    result = classInfoProvider.getClassInfo(className).getType();
+                    typeCache.put(className, result);
                 }
-                result = classInfoProvider.getClassInfo(className).getType();
-                typeCache.put(className, result);
             }
         }
         return result;

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

@@ -43,6 +43,7 @@ import org.teavm.model.ClassReaderSource;
 import org.teavm.model.ElementModifier;
 import org.teavm.model.ListableClassReaderSource;
 import org.teavm.model.MethodReference;
+import org.teavm.model.lowlevel.Characteristics;
 
 public class WasmGCGenerationContext implements BaseWasmGenerationContext {
     private WasmModule module;
@@ -69,6 +70,7 @@ public class WasmGCGenerationContext implements BaseWasmGenerationContext {
     private String entryPoint;
     private Consumer<WasmGCInitializerContributor> initializerContributors;
     private Diagnostics diagnostics;
+    private Characteristics characteristics;
 
     public WasmGCGenerationContext(WasmModule module, WasmGCVirtualTableProvider virtualTables,
             WasmGCTypeMapper typeMapper, WasmFunctionTypes functionTypes, ListableClassReaderSource classes,
@@ -78,7 +80,7 @@ public class WasmGCGenerationContext implements BaseWasmGenerationContext {
             WasmGCCustomGeneratorProvider customGenerators, WasmGCIntrinsicProvider intrinsics,
             WasmGCNameProvider names, boolean strict, String entryPoint,
             Consumer<WasmGCInitializerContributor> initializerContributors,
-            Diagnostics diagnostics) {
+            Diagnostics diagnostics, Characteristics characteristics) {
         this.module = module;
         this.virtualTables = virtualTables;
         this.typeMapper = typeMapper;
@@ -98,6 +100,7 @@ public class WasmGCGenerationContext implements BaseWasmGenerationContext {
         this.entryPoint = entryPoint;
         this.initializerContributors = initializerContributors;
         this.diagnostics = diagnostics;
+        this.characteristics = characteristics;
     }
 
     public WasmGCClassInfoProvider classInfoProvider() {
@@ -210,6 +213,10 @@ public class WasmGCGenerationContext implements BaseWasmGenerationContext {
         return diagnostics;
     }
 
+    public Characteristics characteristics() {
+        return characteristics;
+    }
+
     public Collection<String> getInterfaceImplementors(String className) {
         if (interfaceImplementors == null) {
             fillInterfaceImplementors();

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

@@ -15,6 +15,8 @@
  */
 package org.teavm.backend.wasm.generate.gc.methods;
 
+import static org.teavm.model.lowlevel.ExceptionHandlingUtil.isManagedMethodCall;
+
 import java.util.ArrayList;
 import java.util.List;
 import java.util.function.Consumer;
@@ -97,6 +99,7 @@ public class WasmGCGenerationVisitor extends BaseWasmGenerationVisitor {
     private WasmGCGenerationUtil generationUtil;
     private WasmType expectedType;
     private PreciseTypeInference types;
+    private boolean managed;
 
     public WasmGCGenerationVisitor(WasmGCGenerationContext context, MethodReference currentMethod,
             WasmFunction function, int firstVariable, boolean async, PreciseTypeInference types) {
@@ -104,6 +107,7 @@ public class WasmGCGenerationVisitor extends BaseWasmGenerationVisitor {
         this.context = context;
         generationUtil = new WasmGCGenerationUtil(context.classInfoProvider());
         this.types = types;
+        managed = context.characteristics().isManaged(currentMethod);
     }
 
     @Override
@@ -125,7 +129,7 @@ public class WasmGCGenerationVisitor extends BaseWasmGenerationVisitor {
 
     @Override
     protected boolean isManaged() {
-        return true;
+        return managed;
     }
 
     @Override
@@ -135,7 +139,7 @@ public class WasmGCGenerationVisitor extends BaseWasmGenerationVisitor {
 
     @Override
     protected boolean isManagedCall(MethodReference method) {
-        return false;
+        return isManagedMethodCall(context.characteristics(), method);
     }
 
     @Override

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

@@ -61,6 +61,7 @@ import org.teavm.model.MethodReader;
 import org.teavm.model.MethodReference;
 import org.teavm.model.ValueType;
 import org.teavm.model.analysis.ClassInitializerInfo;
+import org.teavm.model.lowlevel.Characteristics;
 import org.teavm.model.util.RegisterAllocator;
 
 public class WasmGCMethodGenerator implements BaseWasmFunctionRepository {
@@ -74,6 +75,7 @@ public class WasmGCMethodGenerator implements BaseWasmFunctionRepository {
     private WasmGCSupertypeFunctionProvider supertypeFunctions;
     public final WasmGCNameProvider names;
     private Diagnostics diagnostics;
+    private Characteristics characteristics;
     private WasmGCTypeMapper typeMapper;
     private WasmGCCustomGeneratorProvider customGenerators;
     private WasmGCIntrinsicProvider intrinsics;
@@ -101,6 +103,7 @@ public class WasmGCMethodGenerator implements BaseWasmFunctionRepository {
             WasmFunctionTypes functionTypes,
             WasmGCNameProvider names,
             Diagnostics diagnostics,
+            Characteristics characteristics,
             WasmGCCustomGeneratorProvider customGenerators,
             WasmGCIntrinsicProvider intrinsics,
             boolean strict,
@@ -116,6 +119,7 @@ public class WasmGCMethodGenerator implements BaseWasmFunctionRepository {
         this.functionTypes = functionTypes;
         this.names = names;
         this.diagnostics = diagnostics;
+        this.characteristics = characteristics;
         this.customGenerators = customGenerators;
         this.intrinsics = intrinsics;
         this.strict = strict;
@@ -367,7 +371,8 @@ public class WasmGCMethodGenerator implements BaseWasmFunctionRepository {
                     strict,
                     entryPoint,
                     initializerContributors,
-                    diagnostics
+                    diagnostics,
+                    characteristics
             );
         }
         return context;

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

@@ -0,0 +1,157 @@
+/*
+ *  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 java.util.stream.Collectors;
+import org.teavm.ast.InvocationExpr;
+import org.teavm.backend.wasm.WasmRuntime;
+import org.teavm.backend.wasm.model.WasmNumType;
+import org.teavm.backend.wasm.model.expression.WasmCall;
+import org.teavm.backend.wasm.model.expression.WasmConversion;
+import org.teavm.backend.wasm.model.expression.WasmExpression;
+import org.teavm.backend.wasm.model.expression.WasmInt32Constant;
+import org.teavm.backend.wasm.model.expression.WasmInt32Subtype;
+import org.teavm.backend.wasm.model.expression.WasmInt64Subtype;
+import org.teavm.backend.wasm.model.expression.WasmIntBinary;
+import org.teavm.backend.wasm.model.expression.WasmIntBinaryOperation;
+import org.teavm.backend.wasm.model.expression.WasmIntType;
+import org.teavm.backend.wasm.model.expression.WasmLoadFloat32;
+import org.teavm.backend.wasm.model.expression.WasmLoadFloat64;
+import org.teavm.backend.wasm.model.expression.WasmLoadInt32;
+import org.teavm.backend.wasm.model.expression.WasmLoadInt64;
+import org.teavm.backend.wasm.model.expression.WasmStoreFloat32;
+import org.teavm.backend.wasm.model.expression.WasmStoreFloat64;
+import org.teavm.backend.wasm.model.expression.WasmStoreInt32;
+import org.teavm.backend.wasm.model.expression.WasmStoreInt64;
+import org.teavm.model.MethodReference;
+import org.teavm.model.ValueType;
+
+public class AddressIntrinsic implements WasmGCIntrinsic {
+
+    @Override
+    public WasmExpression apply(InvocationExpr invocation, WasmGCIntrinsicContext manager) {
+        switch (invocation.getMethod().getName()) {
+            case "toInt":
+            case "toStructure":
+                return manager.generate(invocation.getArguments().get(0));
+            case "toLong": {
+                WasmExpression value = manager.generate(invocation.getArguments().get(0));
+                return new WasmConversion(WasmNumType.INT32, WasmNumType.INT64, false, value);
+            }
+            case "fromInt":
+                return manager.generate(invocation.getArguments().get(0));
+            case "fromLong": {
+                WasmExpression value = manager.generate(invocation.getArguments().get(0));
+                return new WasmConversion(WasmNumType.INT64, WasmNumType.INT32, false, value);
+            }
+            case "add": {
+                WasmExpression base = manager.generate(invocation.getArguments().get(0));
+                if (invocation.getMethod().parameterCount() == 1) {
+                    WasmExpression offset = manager.generate(invocation.getArguments().get(1));
+                    if (invocation.getMethod().parameterType(0) == ValueType.LONG) {
+                        offset = new WasmConversion(WasmNumType.INT64, WasmNumType.INT32, false, offset);
+                    }
+                    return new WasmIntBinary(WasmIntType.INT32, WasmIntBinaryOperation.ADD, base, offset);
+                } else {
+                    throw new IllegalArgumentException(invocation.getMethod().toString());
+                }
+            }
+            case "getByte":
+                return new WasmLoadInt32(1, manager.generate(invocation.getArguments().get(0)),
+                        WasmInt32Subtype.INT8);
+            case "getShort":
+                return new WasmLoadInt32(2, manager.generate(invocation.getArguments().get(0)),
+                        WasmInt32Subtype.INT16);
+            case "getChar":
+                return new WasmLoadInt32(2, manager.generate(invocation.getArguments().get(0)),
+                        WasmInt32Subtype.UINT16);
+            case "getAddress":
+            case "getInt":
+                return new WasmLoadInt32(4, manager.generate(invocation.getArguments().get(0)),
+                        WasmInt32Subtype.INT32);
+            case "getLong":
+                return new WasmLoadInt64(8, manager.generate(invocation.getArguments().get(0)),
+                        WasmInt64Subtype.INT64);
+            case "getFloat":
+                return new WasmLoadFloat32(4, manager.generate(invocation.getArguments().get(0)));
+            case "getDouble":
+                return new WasmLoadFloat64(8, manager.generate(invocation.getArguments().get(0)));
+            case "putByte": {
+                WasmExpression address = manager.generate(invocation.getArguments().get(0));
+                WasmExpression value = manager.generate(invocation.getArguments().get(1));
+                return new WasmStoreInt32(1, address, value, WasmInt32Subtype.INT8);
+            }
+            case "putShort": {
+                WasmExpression address = manager.generate(invocation.getArguments().get(0));
+                WasmExpression value = manager.generate(invocation.getArguments().get(1));
+                return new WasmStoreInt32(2, address, value, WasmInt32Subtype.INT16);
+            }
+            case "putChar": {
+                WasmExpression address = manager.generate(invocation.getArguments().get(0));
+                WasmExpression value = manager.generate(invocation.getArguments().get(1));
+                return new WasmStoreInt32(2, address, value, WasmInt32Subtype.UINT16);
+            }
+            case "putAddress":
+            case "putInt": {
+                WasmExpression address = manager.generate(invocation.getArguments().get(0));
+                WasmExpression value = manager.generate(invocation.getArguments().get(1));
+                return new WasmStoreInt32(4, address, value, WasmInt32Subtype.INT32);
+            }
+            case "putLong": {
+                WasmExpression address = manager.generate(invocation.getArguments().get(0));
+                WasmExpression value = manager.generate(invocation.getArguments().get(1));
+                return new WasmStoreInt64(8, address, value, WasmInt64Subtype.INT64);
+            }
+            case "putFloat": {
+                WasmExpression address = manager.generate(invocation.getArguments().get(0));
+                WasmExpression value = manager.generate(invocation.getArguments().get(1));
+                return new WasmStoreFloat32(4, address, value);
+            }
+            case "putDouble": {
+                WasmExpression address = manager.generate(invocation.getArguments().get(0));
+                WasmExpression value = manager.generate(invocation.getArguments().get(1));
+                return new WasmStoreFloat64(8, address, value);
+            }
+            case "sizeOf":
+                return new WasmInt32Constant(4);
+            case "align": {
+                MethodReference delegate = new MethodReference(WasmRuntime.class.getName(),
+                        invocation.getMethod().getDescriptor());
+                WasmCall call = new WasmCall(manager.functions().forStaticMethod(delegate));
+                call.getArguments().addAll(invocation.getArguments().stream()
+                        .map(arg -> manager.generate(arg))
+                        .collect(Collectors.toList()));
+                return call;
+            }
+            case "isLessThan":
+                return new WasmIntBinary(WasmIntType.INT32, WasmIntBinaryOperation.LT_UNSIGNED,
+                        manager.generate(invocation.getArguments().get(0)),
+                        manager.generate(invocation.getArguments().get(1)));
+            case "diff": {
+                WasmExpression result = new WasmIntBinary(WasmIntType.INT32, WasmIntBinaryOperation.SUB,
+                        manager.generate(invocation.getArguments().get(0)),
+                        manager.generate(invocation.getArguments().get(1))
+                );
+                result = new WasmConversion(WasmNumType.INT32, WasmNumType.INT64, true, result);
+                result.setLocation(invocation.getLocation());
+                return result;
+            }
+            default:
+                throw new IllegalArgumentException(invocation.getMethod().toString());
+        }
+    }
+
+}

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

@@ -0,0 +1,84 @@
+/*
+ *  Copyright 2024 lax1dude.
+ *
+ *  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.model.expression.WasmCall;
+import org.teavm.backend.wasm.model.expression.WasmCopy;
+import org.teavm.backend.wasm.model.expression.WasmExpression;
+import org.teavm.backend.wasm.model.expression.WasmFill;
+import org.teavm.backend.wasm.model.expression.WasmInt32Constant;
+import org.teavm.backend.wasm.model.expression.WasmUnreachable;
+import org.teavm.interop.Address;
+import org.teavm.model.MethodReference;
+import org.teavm.runtime.LaxMalloc;
+
+public class DirectMallocIntrinsic implements WasmGCIntrinsic {
+    private static final MethodReference LAX_MALLOC = new MethodReference(LaxMalloc.class, "laxMalloc", int.class,
+            Address.class);
+    private static final MethodReference LAX_CALLOC = new MethodReference(LaxMalloc.class, "laxCalloc", int.class,
+            Address.class);
+    private static final MethodReference LAX_FREE = new MethodReference(LaxMalloc.class, "laxFree", Address.class,
+            void.class);
+
+    @Override
+    public WasmExpression apply(InvocationExpr invocation, WasmGCIntrinsicContext manager) {
+        switch (invocation.getMethod().getName()) {
+            case "malloc": {
+                var function = manager.functions().forStaticMethod(LAX_MALLOC);
+                var call = new WasmCall(function);
+                call.getArguments().add(manager.generate(invocation.getArguments().get(0)));
+                return call;
+            }
+            case "calloc": {
+                var function = manager.functions().forStaticMethod(LAX_CALLOC);
+                var call = new WasmCall(function);
+                call.getArguments().add(manager.generate(invocation.getArguments().get(0)));
+                return call;
+            }
+            case "free": {
+                var function = manager.functions().forStaticMethod(LAX_FREE);
+                var call = new WasmCall(function);
+                call.getArguments().add(manager.generate(invocation.getArguments().get(0)));
+                return call;
+            }
+            case "memcpy": {
+                var copy = new WasmCopy();
+                copy.setDestinationIndex(manager.generate(invocation.getArguments().get(0)));
+                copy.setSourceIndex(manager.generate(invocation.getArguments().get(1)));
+                copy.setCount(manager.generate(invocation.getArguments().get(2)));
+                return copy;
+            }
+            case "memset": {
+                var fill = new WasmFill();
+                fill.setIndex(manager.generate(invocation.getArguments().get(0)));
+                fill.setValue(manager.generate(invocation.getArguments().get(1)));
+                fill.setCount(manager.generate(invocation.getArguments().get(2)));
+                return fill;
+            }
+            case "zmemset": {
+                var fill = new WasmFill();
+                fill.setIndex(manager.generate(invocation.getArguments().get(0)));
+                fill.setValue(new WasmInt32Constant(0));
+                fill.setCount(manager.generate(invocation.getArguments().get(1)));
+                return fill;
+            }
+            default:
+                return new WasmUnreachable();
+        }
+    }
+
+}

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

@@ -0,0 +1,95 @@
+/*
+ *  Copyright 2024 lax1dude.
+ *
+ *  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 java.util.ArrayList;
+import java.util.List;
+import org.teavm.ast.InvocationExpr;
+import org.teavm.backend.wasm.model.expression.WasmExpression;
+import org.teavm.backend.wasm.model.expression.WasmInt32Constant;
+import org.teavm.backend.wasm.model.expression.WasmIntBinary;
+import org.teavm.backend.wasm.model.expression.WasmIntBinaryOperation;
+import org.teavm.backend.wasm.model.expression.WasmIntType;
+import org.teavm.backend.wasm.model.expression.WasmMemoryGrow;
+
+public class LaxMallocIntrinsic implements WasmGCIntrinsic {
+
+    private final List<LaxMallocHeapMapper> addressList = new ArrayList<>();
+    private final List<WasmInt32Constant> minAddrConstants = new ArrayList<>();
+    private final List<WasmInt32Constant> maxAddrConstants = new ArrayList<>();
+
+    @Override
+    public WasmExpression apply(InvocationExpr invocation, WasmGCIntrinsicContext context) {
+        switch (invocation.getMethod().getName()) {
+            case "addrHeap": {
+                WasmExpression value = context.generate(invocation.getArguments().get(0));
+                if (value instanceof WasmInt32Constant) {
+                    // if addrHeap is passed a constant i32, add the heap offset at compile time
+                    final int memOffset = ((WasmInt32Constant) value).getValue();
+                    WasmInt32Constant ret = new WasmInt32Constant(0);
+                    addressList.add(heapLoc -> {
+                        ret.setValue(heapLoc + memOffset);
+                    });
+                    return ret;
+                } else {
+                    WasmInt32Constant heapLocConst = new WasmInt32Constant(0);
+                    WasmExpression calcOffset = new WasmIntBinary(WasmIntType.INT32, WasmIntBinaryOperation.ADD,
+                            heapLocConst, value);
+                    addressList.add(heapLocConst::setValue);
+                    return calcOffset;
+                }
+            }
+            case "growHeapOuter": {
+                return new WasmMemoryGrow(context.generate(invocation.getArguments().get(0)));
+            }
+            case "getHeapMinAddr": {
+                WasmInt32Constant ret = new WasmInt32Constant(0);
+                minAddrConstants.add(ret);
+                return ret;
+            }
+            case "getHeapMaxAddr": {
+                WasmInt32Constant ret = new WasmInt32Constant(0);
+                maxAddrConstants.add(ret);
+                return ret;
+            }
+            default:
+                throw new IllegalArgumentException(invocation.getMethod().toString());
+        }
+    }
+
+    public void setHeapLocation(int heapLoc) {
+        for (LaxMallocHeapMapper mapper : addressList) {
+            mapper.setHeapLocation(heapLoc);
+        }
+    }
+
+    private interface LaxMallocHeapMapper {
+        void setHeapLocation(int heapLoc);
+    }
+
+    public void setHeapMinAddr(int heapSegmentMinAddr) {
+        for (WasmInt32Constant ct : minAddrConstants) {
+            ct.setValue(heapSegmentMinAddr);
+        }
+    }
+
+    public void setHeapMaxAddr(int heapSegmentMaxAddr) {
+        for (WasmInt32Constant ct : maxAddrConstants) {
+            ct.setValue(heapSegmentMaxAddr);
+        }
+    }
+
+}

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

@@ -25,15 +25,19 @@ import org.teavm.backend.wasm.model.expression.WasmIntType;
 import org.teavm.backend.wasm.runtime.StringInternPool;
 import org.teavm.backend.wasm.runtime.gc.WasmGCResources;
 import org.teavm.common.ServiceRepository;
+import org.teavm.interop.Address;
+import org.teavm.interop.DirectMalloc;
 import org.teavm.model.ClassReaderSource;
 import org.teavm.model.MethodReference;
 import org.teavm.model.ValueType;
+import org.teavm.runtime.LaxMalloc;
 
 public class WasmGCIntrinsics implements WasmGCIntrinsicProvider {
     private Map<MethodReference, IntrinsicContainer> intrinsics = new HashMap<>();
     private List<WasmGCIntrinsicFactory> factories;
     private ClassReaderSource classes;
     private ServiceRepository services;
+    private LaxMallocIntrinsic laxMallocIntrinsic;
 
     public WasmGCIntrinsics(ClassReaderSource classes, ServiceRepository services,
             List<WasmGCIntrinsicFactory> factories, Map<MethodReference, WasmGCIntrinsic> customIntrinsics) {
@@ -51,6 +55,9 @@ public class WasmGCIntrinsics implements WasmGCIntrinsicProvider {
         fillArray();
         fillString();
         fillResources();
+        fillDirectMalloc();
+        fillLaxMalloc();
+        fillAddress();
         for (var entry : customIntrinsics.entrySet()) {
             add(entry.getKey(), entry.getValue());
         }
@@ -166,6 +173,58 @@ public class WasmGCIntrinsics implements WasmGCIntrinsicProvider {
         add(new MethodReference(WasmGCResources.class, "readSingleByte", int.class, int.class), intrinsic);
     }
 
+    private void fillDirectMalloc() {
+        var intrinsic = new DirectMallocIntrinsic();
+        add(new MethodReference(DirectMalloc.class, "malloc", int.class, Address.class), intrinsic);
+        add(new MethodReference(DirectMalloc.class, "calloc", int.class, Address.class), intrinsic);
+        add(new MethodReference(DirectMalloc.class, "free", Address.class, void.class), intrinsic);
+        add(new MethodReference(DirectMalloc.class, "memcpy", Address.class, Address.class, int.class, void.class),
+                intrinsic);
+        add(new MethodReference(DirectMalloc.class, "memset", Address.class, int.class, int.class, void.class),
+                intrinsic);
+        add(new MethodReference(DirectMalloc.class, "zmemset", Address.class, int.class, void.class), intrinsic);
+    }
+
+    private void fillLaxMalloc() {
+        laxMallocIntrinsic = new LaxMallocIntrinsic();
+        add(new MethodReference(LaxMalloc.class, "addrHeap", int.class, Address.class), laxMallocIntrinsic);
+        add(new MethodReference(LaxMalloc.class, "growHeapOuter", int.class, int.class), laxMallocIntrinsic);
+        add(new MethodReference(LaxMalloc.class, "getHeapMinAddr", Address.class), laxMallocIntrinsic);
+        add(new MethodReference(LaxMalloc.class, "getHeapMaxAddr", Address.class), laxMallocIntrinsic);
+    }
+
+    private void fillAddress() {
+        var intrinsic = new AddressIntrinsic();
+        add(new MethodReference(Address.class, "add", int.class, Address.class), intrinsic);
+        add(new MethodReference(Address.class, "add", long.class, Address.class), intrinsic);
+        add(new MethodReference(Address.class, "isLessThan", Address.class, boolean.class), intrinsic);
+        add(new MethodReference(Address.class, "toInt", int.class), intrinsic);
+        add(new MethodReference(Address.class, "toLong", long.class), intrinsic);
+        //add(new MethodReference(Address.class, "toStructure", ?????), intrinsic); //TODO
+        add(new MethodReference(Address.class, "getByte", byte.class), intrinsic);
+        add(new MethodReference(Address.class, "putByte", byte.class, void.class), intrinsic);
+        add(new MethodReference(Address.class, "getChar", char.class), intrinsic);
+        add(new MethodReference(Address.class, "putChar", char.class, void.class), intrinsic);
+        add(new MethodReference(Address.class, "getShort", short.class), intrinsic);
+        add(new MethodReference(Address.class, "putShort", short.class, void.class), intrinsic);
+        add(new MethodReference(Address.class, "getInt", int.class), intrinsic);
+        add(new MethodReference(Address.class, "putInt", int.class, void.class), intrinsic);
+        add(new MethodReference(Address.class, "getLong", long.class), intrinsic);
+        add(new MethodReference(Address.class, "putLong", long.class, void.class), intrinsic);
+        add(new MethodReference(Address.class, "getFloat", float.class), intrinsic);
+        add(new MethodReference(Address.class, "putFloat", float.class, void.class), intrinsic);
+        add(new MethodReference(Address.class, "getDouble", double.class), intrinsic);
+        add(new MethodReference(Address.class, "putDouble", double.class, void.class), intrinsic);
+        add(new MethodReference(Address.class, "getAddress", Address.class), intrinsic);
+        add(new MethodReference(Address.class, "putAddress", Address.class, void.class), intrinsic);
+        add(new MethodReference(Address.class, "fromInt", int.class, Address.class), intrinsic);
+        add(new MethodReference(Address.class, "fromLong", long.class, Address.class), intrinsic);
+        add(new MethodReference(Address.class, "align", Address.class, int.class, Address.class), intrinsic);
+        add(new MethodReference(Address.class, "sizeOf", int.class), intrinsic);
+        add(new MethodReference(Address.class, "add", Class.class, int.class), intrinsic);
+        add(new MethodReference(Address.class, "diff", Address.class, long.class), intrinsic);
+    }
+
     private void add(MethodReference methodRef, WasmGCIntrinsic intrinsic) {
         intrinsics.put(methodRef, new IntrinsicContainer(intrinsic));
     }
@@ -187,6 +246,12 @@ public class WasmGCIntrinsics implements WasmGCIntrinsicProvider {
         return result.intrinsic;
     }
 
+    public void setupLaxMallocHeap(int heapAddr, int heapSegmentMinAddr, int heapSegmentMaxAddr) {
+        laxMallocIntrinsic.setHeapLocation(heapAddr);
+        laxMallocIntrinsic.setHeapMinAddr(heapSegmentMinAddr);
+        laxMallocIntrinsic.setHeapMaxAddr(heapSegmentMaxAddr);
+    }
+
     static class IntrinsicContainer {
         final WasmGCIntrinsic intrinsic;
 

core/src/main/java/org/teavm/runtime/LaxMalloc.java

@@ -0,0 +1,643 @@
+/*
+ *  Copyright 2024 lax1dude.
+ *
+ *  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.runtime;
+
+import org.teavm.interop.Address;
+import org.teavm.interop.DirectMalloc;
+import org.teavm.interop.Import;
+import org.teavm.interop.StaticInit;
+import org.teavm.interop.Unmanaged;
+
+/**
+ * Linear memory allocator for creating "direct buffers" in WASM GC<br><br>
+ * 
+ * DO NOT USE IN LEGACY WASM BACKEND!!! Make a regular byte array, and use Address.ofData()<br><br>
+ * 
+ * Similar to dlmalloc and emmalloc (emscripten's malloc)<br><br>
+ * 
+ * bad things will happen if you free an address that was never allocated
+ * 
+ * @author lax1dude
+ */
+@Unmanaged
+@StaticInit
+public final class LaxMalloc {
+
+    private LaxMalloc() {
+    }
+
+    private static final int SIZEOF_PTR = 4;
+    private static final int SIZEOF_PTR_SH = 2;
+
+    private static final int MIN_ALLOC_SIZE = 8;
+
+    // Address where we store the WebAssembly.Memory limit (32 bit int)
+    private static final int ADDR_HEAP_OUTER_LIMIT = 0;
+
+    // Address where we store the current heap limit (32 bit int)
+    private static final int ADDR_HEAP_INNER_LIMIT = 4;
+
+    // Address where we store the bitmask of free chunk lists (64 bit int)
+    private static final int ADDR_HEAP_BUCKETS_FREE_MASK = 8;
+
+    // Address to the list of 64 pointers to the beginnings of the 64 buckets
+    private static final int ADDR_HEAP_BUCKETS_START = 16;
+
+    // Beginning of the first chunk of the heap
+    private static final int ADDR_HEAP_DATA_START = 272;
+
+    // Intrinsic function to get an address in the heap segment
+    private static native Address addrHeap(int offset);
+
+    // Intrinsic function to grow the heap segment
+    private static native int growHeapOuter(int chunks);
+
+    // Intrinsic function to get the minimum direct malloc heap segment ending address
+    private static native Address getHeapMinAddr();
+
+    // Intrinsic function to get the maximum direct malloc heap segment ending address
+    private static native Address getHeapMaxAddr();
+
+    // Function called to resize the JavaScript typed arrays wrapping the WebAssembly.Memory
+    @Import(name = "notifyHeapResized")
+    private static native void notifyHeapResized();
+
+    static {
+        int initialGrowAmount = getHeapMinAddr().toInt() >>> 16;
+        if (growHeapOuter(initialGrowAmount) == -1) {
+            initialGrowAmount = 1;
+            if (growHeapOuter(initialGrowAmount) == -1) {
+                //TODO: Handle failure to initialize fallback 64KiB heap
+            }
+        }
+        
+        // zero out the control region
+        DirectMalloc.zmemset(addrHeap(0), ADDR_HEAP_DATA_START);
+        // initialize heap limit
+        addrHeap(ADDR_HEAP_INNER_LIMIT).putAddress(addrHeap(ADDR_HEAP_DATA_START));
+        addrHeap(ADDR_HEAP_OUTER_LIMIT).putAddress(addrHeap(initialGrowAmount << 16));
+    }
+
+    /**
+     * malloc implementation
+     */
+    public static Address laxMalloc(int sizeBytes) {
+        return laxAlloc(sizeBytes, false);
+    }
+
+    /**
+     * calloc implementation (zeroed malloc)
+     */
+    public static Address laxCalloc(int sizeBytes) {
+        return laxAlloc(sizeBytes, true);
+    }
+
+    private static Address laxAlloc(int sizeBytes, boolean cleared) {
+        if (sizeBytes <= 0) {
+            // Produce a null pointer if 0 or invalid size is requested
+            return Address.fromInt(0);
+        }
+        
+        // Allocation must be large enough to hold the two list pointers when the chunk becomes free again
+        if (sizeBytes < MIN_ALLOC_SIZE) {
+            sizeBytes = MIN_ALLOC_SIZE;
+        }
+        
+        // Make sure all allocations are at least a multiple of 4 to maintain alignment 
+        sizeBytes = (sizeBytes + 3) & 0xFFFFFFFC;
+        
+        // always between 0-63
+        int bucket = getListBucket(sizeBytes);
+        
+        if (bucket == 63) {
+            // special bucket for the huge allocations
+            // uses a different slower function
+            return laxHugeAlloc(sizeBytes, cleared);
+        }
+        
+        // load bitmask of buckets with free chunks
+        long bucketMask = addrHeap(ADDR_HEAP_BUCKETS_FREE_MASK).getLong();
+        
+        // mask away the buckets that we know are too small for this allocation
+        bucketMask &= 0xFFFFFFFFFFFFFFFFL << bucket;
+        
+        // there are no more buckets with free chunks
+        // need to sbrk
+        if (bucketMask == 0L) {
+            int sizePlusInts = sizeBytes + 8; // size + 2 ints
+            Address newChunk = growLastChunk(sizePlusInts);
+            
+            // Out of memory
+            if (newChunk.toInt() == 0) {
+                return Address.fromInt(0); //TODO
+            }
+            
+            // provision the new chunk
+            newChunk.putInt(sizePlusInts | 0x80000000); // size + in use flag
+            newChunk.add(sizeBytes + 4).putInt(sizePlusInts); // size integer at the end
+            
+            // return the chunk, +4 bytes to skip size int
+            // we don't need to clear it because its new memory
+            return newChunk.add(4);
+        }
+        
+        // at least one bucket exists containing a free chunk,
+        // quickly determine which bucket it is with bit hacks
+        int availableBucket = Long.numberOfTrailingZeros(bucketMask);
+        
+        Address bucketStartAddr = addrHeap(ADDR_HEAP_BUCKETS_START).add(availableBucket << SIZEOF_PTR_SH);
+        Address chunkPtr = bucketStartAddr.getAddress();
+        int chunkSize = readChunkSizeStatus(chunkPtr);
+        Address itrChunkStart = Address.fromInt(0);
+        
+        // check if the first chunk in the bucket is large enough
+        if (chunkSize - 8 < sizeBytes) { // size - 2 ints
+            
+            // the chunk is not large enough, move the first chunk to the end of the list
+            // and then check in the next bucket (where the chunks are definitely large enough)
+            // this functionality is present in emmalloc (emscripten)
+            
+            Address chunkNextPtr = readChunkNextFreeAddr(chunkPtr);
+            if (chunkNextPtr.getInt() != chunkPtr.getInt()) {
+                bucketStartAddr.putAddress(chunkNextPtr);
+                itrChunkStart = chunkNextPtr;
+            }
+            
+            // extend mask to the next bucket
+            bucketMask &= 0xFFFFFFFFFFFFFFFFL << (bucket + 1);
+            
+            if (bucketMask != 0L) {
+                // there is a bucket with a larger chunk
+                int availableLargerBucket = Long.numberOfTrailingZeros(bucketMask);
+                Address largerBucketStartAddr = addrHeap(ADDR_HEAP_BUCKETS_START)
+                        .add(availableLargerBucket << SIZEOF_PTR_SH);
+                Address largerChunkPtr = largerBucketStartAddr.getAddress();
+                int largerChunkSize = readChunkSizeStatus(largerChunkPtr);
+                
+                // this will remove the chunk from the free list
+                allocateMemoryFromChunk(largerChunkPtr, largerChunkSize, sizeBytes);
+                
+                // +4 bytes to skip size int
+                Address ret = largerChunkPtr.add(4);
+                
+                // clear if requested
+                if (cleared) {
+                    DirectMalloc.zmemset(ret, sizeBytes);
+                }
+                
+                return ret;
+            }
+        } else {
+            // the first chunk in the bucket is large enough
+            // this will remove the chunk from the free list
+            allocateMemoryFromChunk(chunkPtr, chunkSize, sizeBytes);
+            
+            // +4 bytes to skip size int
+            Address ret = chunkPtr.add(4);
+            
+            // clear if requested
+            if (cleared) {
+                DirectMalloc.zmemset(ret, sizeBytes);
+            }
+            
+            return ret;
+        }
+        
+        if (itrChunkStart.toInt() != 0) {
+            
+            // if we've reached this point, it means the first chunk in the bucket wasn't large enough
+            // and there weren't any chunks in the larger buckets we could split up
+            // so we need to look closer
+            
+            // iterate the (only) bucket of possibly large enough chunks
+            Address addrIterator = itrChunkStart;
+            do {
+                chunkSize = readChunkSizeStatus(addrIterator);
+                
+                // check if the chunk is large enough
+                if (chunkSize - 8 >= sizeBytes) { // size - 2 ints
+                    // we've found a large enough chunk
+                    // this will remove the chunk from the free list
+                    allocateMemoryFromChunk(addrIterator, chunkSize, sizeBytes);
+                    
+                    // +4 bytes to skip size int
+                    Address ret = addrIterator.add(4);
+                    
+                    // clear if requested
+                    if (cleared) {
+                        DirectMalloc.zmemset(ret, sizeBytes);
+                    }
+                    
+                    return ret;
+                }
+                addrIterator = readChunkNextFreeAddr(addrIterator);
+            } while (addrIterator.getInt() != chunkPtr.getInt());
+        }
+        
+        // no other options, time to sbrk
+        
+        int sizePlusInts = sizeBytes + 8; // size + 2 ints
+        Address newChunk = growLastChunk(sizePlusInts);
+        
+        // Out of memory
+        if (newChunk.toInt() == 0) {
+            return Address.fromInt(0); //TODO
+        }
+        
+        // provision the new chunk
+        newChunk.putInt(sizePlusInts | 0x80000000); // size + in use flag
+        newChunk.add(sizeBytes + 4).putInt(sizePlusInts); // size integer at the end
+        
+        // return the chunk, +4 bytes to skip size int
+        // we don't need to clear it because its new memory
+        return newChunk.add(4);
+    }
+
+    private static Address laxHugeAlloc(int sizeBytes, boolean cleared) {
+        
+        // check the bucket mask if bucket 63 has any chunks
+        if ((addrHeap(ADDR_HEAP_BUCKETS_FREE_MASK).getLong() & 0x8000000000000000L) != 0) {
+
+            // bucket 63 address
+            Address bucketStartAddr = addrHeap(ADDR_HEAP_BUCKETS_START).add(63 << SIZEOF_PTR_SH);
+            Address chunkPtr = bucketStartAddr.getAddress();
+            
+            // iterate all free huge chunks
+            Address addrIterator = chunkPtr;
+            do {
+                int chunkSize = readChunkSizeStatus(addrIterator);
+                
+                if (chunkSize - 8 >= sizeBytes) { // size - 2 ints
+                    // we've found a large enough chunk
+                    // this will remove the chunk from the free list
+                    allocateMemoryFromChunk(addrIterator, chunkSize, sizeBytes);
+                    
+                    // +4 bytes to skip size int
+                    Address ret = addrIterator.add(4);
+                    
+                    // clear if requested
+                    if (cleared) {
+                        DirectMalloc.zmemset(ret, sizeBytes);
+                    }
+                    
+                    return ret;
+                }
+                addrIterator = readChunkNextFreeAddr(addrIterator);
+            } while (addrIterator.getInt() != chunkPtr.getInt());
+        }
+        
+        // no free huge chunks found, time to sbrk
+        
+        int sizePlusInts = sizeBytes + 8; // size + 2 ints
+        Address newChunk = growLastChunk(sizePlusInts);
+        
+        // Out of memory
+        if (newChunk.toInt() == 0) {
+            return Address.fromInt(0); //TODO
+        }
+        
+        // provision the new chunk
+        newChunk.putInt(sizePlusInts | 0x80000000); // size + in use flag
+        newChunk.add(sizeBytes + 4).putInt(sizePlusInts); // size integer at the end
+        
+        // return the chunk, +4 bytes to skip size int
+        // we don't need to clear it because its new memory
+        return newChunk.add(4);
+    }
+
+    /**
+     * free implementation<br><br>
+     * 
+     * bad things will happen if you free an address that was never allocated
+     */
+    public static void laxFree(Address address) {
+        if (address.toInt() == 0) {
+            return;
+        }
+        
+        // chunk actually starts 4 bytes before
+        Address chunkPtr = address.add(-4);
+        
+        // bring the size of the chunk into the stack
+        int chunkSize = chunkPtr.getInt();
+        boolean sizeChanged = false;
+        
+        // set the chunk no longer in use
+        chunkSize &= 0x7FFFFFFF;
+        
+        if (addrHeap(ADDR_HEAP_DATA_START).isLessThan(chunkPtr)) {
+            Address prevChunkPtr = chunkPtr.add(-(chunkPtr.add(-4).getInt()));
+            if (!prevChunkPtr.isLessThan(addrHeap(ADDR_HEAP_DATA_START))) {
+                // check if we can merge with the previous chunk, and move it to another bucket
+                int prevChunkSize = readChunkSizeStatus(prevChunkPtr);
+                if ((prevChunkSize & 0x80000000) == 0) {
+                    // previous chunk is not in use, merge!
+                    
+                    // remove the previous chunk from its list
+                    unlinkChunkFromFreeList(prevChunkPtr, prevChunkSize);
+                    
+                    // resize the current chunk to also contain the previous chunk
+                    chunkPtr = prevChunkPtr;
+                    chunkSize += prevChunkSize;
+                    sizeChanged = true;
+                }
+            }
+        }
+        
+        Address nextChunkPtr = chunkPtr.add(chunkSize);
+        if (nextChunkPtr.isLessThan(addrHeap(ADDR_HEAP_INNER_LIMIT).getAddress())) {
+            // check if we can merge with the next chunk as well
+            int nextChunkSize = readChunkSizeStatus(nextChunkPtr);
+            if ((nextChunkSize & 0x80000000) == 0) {
+                // next chunk is not in use, merge!
+
+                // remove the next chunk from its list
+                unlinkChunkFromFreeList(nextChunkPtr, nextChunkSize);
+                
+                // resize the current chunk to also contain the next chunk
+                chunkSize += nextChunkSize;
+                sizeChanged = true;
+            }
+        }
+        
+        // store the final chunk size (also clears the in use flag)
+        chunkPtr.putInt(chunkSize);
+        
+        if (sizeChanged) {
+            // if the size of the chunk changed, we also need to update the chunk's second size integer
+            chunkPtr.add(chunkSize - 4).putInt(chunkSize);
+        }
+        
+        // add the final chunk to the free chunks list
+        linkChunkInFreeList(chunkPtr, chunkSize);
+    }
+
+    /**
+     * Allocates memory from a free chunk, if the allocSize is smaller than the chunkSize by
+     * enough of a margin then the chunk is split into two smaller chunks, and the upper part
+     * of the chunk is returned to a bucket of free chunks
+     */
+    private static void allocateMemoryFromChunk(Address chunkPtr, int chunkSize, int allocSize) {
+        // remove the chunk from its bucket 
+        unlinkChunkFromFreeList(chunkPtr, chunkSize);
+        
+        int otherHalfSize = chunkSize - allocSize - 8; // -size - 2 ints
+        
+        // check if we can split the chunk into two smaller chunks
+        // chunk must be large enough to hold the 2 list pointers
+        if (otherHalfSize - (2 << SIZEOF_PTR_SH) >= MIN_ALLOC_SIZE) {
+            // chunk is large enough to split
+            
+            // provision the lower part of the chunk, the part we want to use
+            int sizePlusInts = allocSize + 8; // size + 2 ints
+            chunkPtr.putInt(sizePlusInts | 0x80000000); // size + in use flag
+            chunkPtr.add(allocSize + 4).putInt(sizePlusInts); // size integer at the end
+            
+            // provision the upper part of the chunk that we want to return to the free list
+            Address otherChunkPtr = chunkPtr.add(sizePlusInts);
+            otherChunkPtr.putInt(otherHalfSize); // size
+            otherChunkPtr.add(otherHalfSize - 4).putInt(otherHalfSize); // size (end)
+
+            // return the upper part of the chunk to the free chunks list
+            linkChunkInFreeList(otherChunkPtr, otherHalfSize);
+
+        } else {
+            // not large enough to split, just take the entire chunk
+            chunkPtr.putInt(chunkSize | 0x80000000); // sets the in use flag
+        }
+    }
+
+    /**
+     * Adds a free chunk to its corresponding bucket
+     */
+    private static void linkChunkInFreeList(Address chunkPtr, int chunkSize) {
+        int bucket = getListBucket(chunkSize - 8); // size - 2 ints
+        
+        long bucketMask = addrHeap(ADDR_HEAP_BUCKETS_FREE_MASK).getLong();
+        Address bucketStartAddr = addrHeap(ADDR_HEAP_BUCKETS_START).add(bucket << SIZEOF_PTR_SH);
+        
+        // test the bucket mask if the bucket is empty
+        if ((bucketMask & (1L << bucket)) == 0L) {
+            
+            // bucket is empty, add the free chunk to the list
+            bucketStartAddr.putAddress(chunkPtr);
+            writeChunkPrevFreeAddr(chunkPtr, chunkPtr);
+            writeChunkNextFreeAddr(chunkPtr, chunkPtr);
+            
+            // set the free bit in bucket mask
+            bucketMask |= 1L << bucket;
+            addrHeap(ADDR_HEAP_BUCKETS_FREE_MASK).putLong(bucketMask);
+            
+        } else {
+            
+            // bucket is not empty, append to the bucket's existing free chunks list
+            Address otherBucketStart = bucketStartAddr.getAddress();
+            Address otherBucketPrev = readChunkPrevFreeAddr(otherBucketStart);
+            
+            // link new chunk to the existing chunks in the bucket
+            writeChunkPrevFreeAddr(chunkPtr, otherBucketPrev);
+            writeChunkNextFreeAddr(chunkPtr, otherBucketStart);
+            
+            // link the existing chunks in the bucket to the new chunk
+            writeChunkPrevFreeAddr(otherBucketStart, chunkPtr);
+            writeChunkNextFreeAddr(otherBucketPrev, chunkPtr);
+            
+            // put the chunk in the bucket
+            bucketStartAddr.putAddress(chunkPtr);
+            
+        }
+    }
+
+    /**
+     * Removes a free chunk from its corresponding bucket
+     */
+    private static void unlinkChunkFromFreeList(Address chunkPtr, int chunkSize) {
+        Address prevChunkPtr = readChunkPrevFreeAddr(chunkPtr);
+        Address nextChunkPtr = readChunkNextFreeAddr(chunkPtr);
+        if (prevChunkPtr.toInt() == chunkPtr.toInt() && nextChunkPtr.toInt() == chunkPtr.toInt()) {
+            // chunk is the only one currently in its bucket
+            
+            int chunkBucket = getListBucket(chunkSize - 8); // size - 2 ints
+            
+            Address bucketStartAddr = addrHeap(ADDR_HEAP_BUCKETS_START).add(chunkBucket << SIZEOF_PTR_SH);
+            bucketStartAddr.putAddress(Address.fromInt(0)); // remove chunk from the bucket
+            
+            // clear the bit in the free buckets bitmask
+            long bucketsFreeMask = addrHeap(ADDR_HEAP_BUCKETS_FREE_MASK).getLong();
+            bucketsFreeMask &= ~(1L << chunkBucket);
+            addrHeap(ADDR_HEAP_BUCKETS_FREE_MASK).putLong(bucketsFreeMask);
+            
+        } else {
+            // there are other chunks in this bucket
+            
+            // link the next chunk to the previous chunk
+            writeChunkNextFreeAddr(prevChunkPtr, nextChunkPtr);
+            writeChunkPrevFreeAddr(nextChunkPtr, prevChunkPtr);
+            
+            int chunkBucket = getListBucket(chunkSize - 8); // size - 2 ints
+            Address bucketStartAddr = addrHeap(ADDR_HEAP_BUCKETS_START).add(chunkBucket << SIZEOF_PTR_SH);
+            Address bucketStartChunk = bucketStartAddr.getAddress();
+            
+            // chunk is the first in the bucket, so we also need to
+            // update the bucket to point to the next chunk instead
+            if (bucketStartChunk.toInt() == chunkPtr.toInt()) {
+                bucketStartAddr.putAddress(nextChunkPtr);
+            }
+        }
+    }
+
+    /**
+     * https://github.com/emscripten-core/emscripten/blob/16a0bf174cb85f88b6d9dcc8ee7fbca59390185b/system/
+     * lib/emmalloc.c#L241
+     * (MIT License)
+     */
+    private static int getListBucket(int allocSize) {
+        if (allocSize < 128) {
+            return (allocSize >> 3) - 1;
+        }
+        
+        int clz = Integer.numberOfLeadingZeros(allocSize);
+        int bucketIndex = (clz > 19) ? 110 - (clz << 2) + ((allocSize >> (29 - clz)) ^ 4)
+                : min(71 - (clz << 1) + ((allocSize >> (30 - clz)) ^ 2), 63);
+        
+        return bucketIndex;
+    }
+
+    /**
+     * Removes the last chunk from the heap (if free), then grows the heap by amount minus
+     * the length of the last chunk, this shouldn't be called unless the program has failed
+     * to find a free chunk that is larger than the requested amount
+     */
+    private static Address growLastChunk(int amount) {
+        Address lastAddr = addrHeap(ADDR_HEAP_INNER_LIMIT).getAddress();
+        
+        // make sure it doesn't crash if the heap is empty
+        if (!addrHeap(ADDR_HEAP_DATA_START).isLessThan(lastAddr)) {
+            return growHeap(amount);
+        }
+        
+        // get the length and address of the last chunk 
+        int lastLen = lastAddr.add(-4).getInt();
+        Address lastChunk = lastAddr.add(-lastLen);
+        lastLen = lastChunk.getInt();
+        
+        // check if the last chunk is free
+        if ((lastLen & 0x80000000) == 0) {
+            
+            // chunk is free, attempt to resize the heap first
+            // so errors can be handled
+            if (growHeap(amount - lastLen).toInt() == 0) {
+                // out of memory
+                return Address.fromInt(0);
+            }
+            
+            // unlink last chunk from free list
+            unlinkChunkFromFreeList(lastChunk, lastLen);
+            
+            // return the start of the last chunk
+            return lastChunk;
+        } else {
+            // no free chunk at the end of the heap
+            // just grow the heap by the full amount
+            return growHeap(amount);
+        }
+    }
+
+    /**
+     * This is our sbrk
+     */
+    private static Address growHeap(int amount) {
+        Address heapInnerLimit = addrHeap(ADDR_HEAP_INNER_LIMIT).getAddress();
+        Address heapOuterLimit = addrHeap(ADDR_HEAP_OUTER_LIMIT).getAddress();
+        Address newHeapInnerLimit = heapInnerLimit.add(amount);
+        if (heapOuterLimit.isLessThan(newHeapInnerLimit)) {
+            int bytesNeeded = newHeapInnerLimit.toInt() - heapOuterLimit.toInt();
+            bytesNeeded = (bytesNeeded + 0xFFFF) & 0xFFFF0000;
+            Address newHeapOuterLimit = heapOuterLimit.add(bytesNeeded);
+            if (!getHeapMaxAddr().isLessThan(newHeapOuterLimit) && growHeapOuter(bytesNeeded >>> 16) != -1) {
+                addrHeap(ADDR_HEAP_INNER_LIMIT).putAddress(newHeapInnerLimit);
+                addrHeap(ADDR_HEAP_OUTER_LIMIT).putAddress(newHeapOuterLimit);
+                notifyHeapResized();
+                return heapInnerLimit;
+            } else {
+                return Address.fromInt(0);
+            }
+        } else {
+            addrHeap(ADDR_HEAP_INNER_LIMIT).putAddress(newHeapInnerLimit);
+            return heapInnerLimit;
+        }
+    }
+
+    /**
+     * Note that on a free chunk, this is the size, because the status bit is 0
+     */
+    private static int readChunkSizeStatus(Address chunkAddr) {
+        return chunkAddr.getInt();
+    }
+
+    private static int readChunkSize(Address chunkAddr) {
+        return chunkAddr.getInt() & 0x7FFFFFFF;
+    }
+
+    private static boolean readChunkInUse(Address chunkAddr) {
+        return (chunkAddr.getInt() & 0x80000000) != 0;
+    }
+
+    private static void writeChunkSizeStatus(Address chunkAddr, int sizeStatus) {
+        chunkAddr.putInt(sizeStatus);
+    }
+
+    private static Address readChunkPrevFreeAddr(Address chunkAddr) {
+        return chunkAddr.add(4).getAddress();
+    }
+
+    private static void writeChunkPrevFreeAddr(Address chunkAddr, Address prevFree) {
+        chunkAddr.add(4).putAddress(prevFree);
+    }
+
+    private static Address readChunkNextFreeAddr(Address chunkAddr) {
+        return chunkAddr.add(4 + (1 << SIZEOF_PTR_SH)).getAddress();
+    }
+
+    private static void writeChunkNextFreeAddr(Address chunkAddr, Address nextFree) {
+        chunkAddr.add(4 + (1 << SIZEOF_PTR_SH)).putAddress(nextFree);
+    }
+
+    private static int min(int a, int b) {
+        return a < b ? a : b;
+    }
+
+//    @Import(name = "dumpHeapHelper")
+//    private static native void dumpHeapHelper(Address chunkStart, Address chunkEnd, int size,
+//            int free, Address endAddr);
+//
+//    public static void heapDump() {
+//        Address curAddr = addrHeap(ADDR_HEAP_DATA_START);
+//        Address endAddr = addrHeap(ADDR_HEAP_INNER_LIMIT).getAddress();
+//        while (curAddr.isLessThan(endAddr)) {
+//            int sizeStat = readChunkSizeStatus(curAddr);
+//            int size = sizeStat & 0x7FFFFFFF;
+//            int stat = sizeStat >>> 31;
+//            dumpHeapHelper(curAddr, curAddr.add(size), size, stat, endAddr);
+//            if (size == 0) {
+//                //NOTE: size 0 would be a bug
+//                return;
+//            }
+//            curAddr = curAddr.add(size);
+//        }
+//    }
+
+}

interop/core/src/main/java/org/teavm/interop/DirectMalloc.java

@@ -0,0 +1,52 @@
+/*
+ *  Copyright 2024 lax1dude.
+ *
+ *  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.interop;
+
+/**
+ * Linear memory allocator for creating "direct buffers" in WASM GC<br><br>
+ * 
+ * DO NOT USE IN LEGACY WASM BACKEND!!! Make a regular byte array, and use Address.ofData()<br><br>
+ * 
+ * Similar to dlmalloc and emmalloc (emscripten's malloc)<br><br>
+ * 
+ * bad things will happen if you free an address that was never allocated
+ * 
+ * @author lax1dude
+ */
+public final class DirectMalloc {
+
+    private DirectMalloc() {
+    }
+
+    @UnsupportedOn({Platforms.JAVASCRIPT, Platforms.WEBASSEMBLY, Platforms.C})
+    public static native Address malloc(int sizeBytes);
+
+    @UnsupportedOn({Platforms.JAVASCRIPT, Platforms.WEBASSEMBLY, Platforms.C})
+    public static native Address calloc(int sizeBytes);
+
+    @UnsupportedOn({Platforms.JAVASCRIPT, Platforms.WEBASSEMBLY, Platforms.C})
+    public static native void free(Address ptr);
+
+    @UnsupportedOn({Platforms.JAVASCRIPT, Platforms.WEBASSEMBLY, Platforms.C})
+    public static native void memcpy(Address dst, Address src, int count);
+
+    @UnsupportedOn({Platforms.JAVASCRIPT, Platforms.WEBASSEMBLY, Platforms.C})
+    public static native void memset(Address ptr, int val, int count);
+
+    @UnsupportedOn({Platforms.JAVASCRIPT, Platforms.WEBASSEMBLY, Platforms.C})
+    public static native void zmemset(Address ptr, int count);
+
+}

tools/core/src/main/java/org/teavm/tooling/TeaVMTool.java

@@ -119,6 +119,7 @@ public class TeaVMTool {
     private Set<File> generatedFiles = new HashSet<>();
     private int minHeapSize = 4 * (1 << 20);
     private int maxHeapSize = 128 * (1 << 20);
+    private boolean directMallocSupport;
     private ReferenceCache referenceCache;
     private boolean heapDump;
     private boolean shortFileNames;
@@ -268,6 +269,10 @@ public class TeaVMTool {
         this.maxHeapSize = maxHeapSize;
     }
 
+    public void setDirectMallocSupport(boolean enableDirectMalloc) {
+        this.directMallocSupport = enableDirectMalloc;
+    }
+
     public ClassLoader getClassLoader() {
         return classLoader;
     }
@@ -411,6 +416,11 @@ public class TeaVMTool {
             target.setSourceMapBuilder(wasmSourceMapWriter);
             target.setSourceMapLocation(getResolvedTargetFileName() + ".map");
         }
+        if (directMallocSupport) {
+            target.setEnableDirectMallocSupport(directMallocSupport);
+            target.setDirectMallocMinHeapSize(minHeapSize);
+            target.setDirectMallocMaxHeapSize(maxHeapSize);
+        }
         return target;
     }
 

tools/core/src/main/java/org/teavm/tooling/builder/BuildStrategy.java

@@ -89,6 +89,8 @@ public interface BuildStrategy {
 
     void setWasmDebugInfoLocation(WasmDebugInfoLocation wasmDebugInfoLocation);
 
+    void setDirectMallocSupport(boolean enable);
+
     void setMinHeapSize(int minHeapSize);
 
     void setMaxHeapSize(int maxHeapSize);

tools/core/src/main/java/org/teavm/tooling/builder/InProcessBuildStrategy.java

@@ -75,6 +75,7 @@ public class InProcessBuildStrategy implements BuildStrategy {
     private TeaVMToolLog log = new EmptyTeaVMToolLog();
     private boolean shortFileNames;
     private boolean assertionsRemoved;
+    private boolean directMallocSupport;
 
     @Override
     public void init() {
@@ -258,6 +259,11 @@ public class InProcessBuildStrategy implements BuildStrategy {
         this.assertionsRemoved = assertionsRemoved;
     }
 
+    @Override
+    public void setDirectMallocSupport(boolean enable) {
+        this.directMallocSupport = enable;
+    }
+
     @Override
     public BuildResult build() throws BuildException {
         TeaVMTool tool = new TeaVMTool();
@@ -289,6 +295,7 @@ public class InProcessBuildStrategy implements BuildStrategy {
         tool.setWasmExceptionsUsed(wasmExceptionsUsed);
         tool.setWasmDebugInfoLevel(wasmDebugInfoLevel);
         tool.setWasmDebugInfoLocation(wasmDebugInfoLocation);
+        tool.setDirectMallocSupport(directMallocSupport);
         tool.setMinHeapSize(minHeapSize);
         tool.setMaxHeapSize(maxHeapSize);
         tool.setHeapDump(heapDump);

tools/core/src/main/java/org/teavm/tooling/builder/RemoteBuildStrategy.java

@@ -214,6 +214,11 @@ public class RemoteBuildStrategy implements BuildStrategy {
         request.maxHeapSize = maxHeapSize;
     }
 
+    @Override
+    public void setDirectMallocSupport(boolean enable) {
+        request.directMallocSupport = enable;
+    }
+
     @Override
     public void setHeapDump(boolean heapDump) {
         request.heapDump = heapDump;

tools/core/src/main/java/org/teavm/tooling/daemon/RemoteBuildRequest.java

@@ -59,4 +59,5 @@ public class RemoteBuildRequest implements Serializable {
     public boolean heapDump;
     public boolean shortFileNames;
     public boolean assertionsRemoved;
+    public boolean directMallocSupport;
 }

tools/gradle/src/main/java/org/teavm/gradle/TeaVMPlugin.java

@@ -231,6 +231,9 @@ public class TeaVMPlugin implements Plugin<Project> {
             task.getStrict().convention(wasmGC.getStrict());
             task.getSourceMap().convention(wasmGC.getSourceMap());
             task.getSourceFilePolicy().convention(wasmGC.getSourceFilePolicy());
+            task.getDirectMallocSupport().convention(wasmGC.getDirectMallocSupport());
+            task.getMinHeapSize().convention(wasmGC.getMinHeapSize());
+            task.getMaxHeapSize().convention(wasmGC.getMaxHeapSize());
             setupSources(task.getSourceFiles(), project);
             buildTask.dependsOn(task);
         });

tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMWasmGCConfiguration.java

@@ -17,7 +17,8 @@ package org.teavm.gradle.api;
 
 import org.gradle.api.provider.Property;
 
-public interface TeaVMWasmGCConfiguration extends TeaVMCommonConfiguration, TeaVMWebConfiguration {
+public interface TeaVMWasmGCConfiguration extends TeaVMCommonConfiguration, TeaVMWebConfiguration,
+        TeaVMNativeBaseConfiguration {
     Property<Boolean> getObfuscated();
 
     Property<Boolean> getStrict();
@@ -37,4 +38,6 @@ public interface TeaVMWasmGCConfiguration extends TeaVMCommonConfiguration, TeaV
     Property<SourceFilePolicy> getSourceFilePolicy();
 
     Property<Boolean> getModularRuntime();
+
+    Property<Boolean> getDirectMallocSupport();
 }

tools/gradle/src/main/java/org/teavm/gradle/tasks/GenerateWasmGCTask.java

@@ -27,6 +27,8 @@ import org.teavm.tooling.TeaVMTargetType;
 import org.teavm.tooling.builder.BuildStrategy;
 
 public abstract class GenerateWasmGCTask extends TeaVMTask {
+    private static final int MB = 1024 * 1024;
+
     public GenerateWasmGCTask() {
         getStrict().convention(true);
         getObfuscated().convention(true);
@@ -34,6 +36,9 @@ public abstract class GenerateWasmGCTask extends TeaVMTask {
         getDebugInfoLocation().convention(WasmDebugInfoLocation.EXTERNAL);
         getSourceMap().convention(false);
         getSourceFilePolicy().convention(SourceFilePolicy.LINK_LOCAL_FILES);
+        getDirectMallocSupport().convention(false);
+        getMinHeapSize().convention(1);
+        getMaxHeapSize().convention(16);
     }
 
     @Input
@@ -58,6 +63,18 @@ public abstract class GenerateWasmGCTask extends TeaVMTask {
     @Optional
     public abstract Property<SourceFilePolicy> getSourceFilePolicy();
 
+    @Input
+    @Optional
+    public abstract Property<Boolean> getDirectMallocSupport();
+
+    @Input
+    @Optional
+    public abstract Property<Integer> getMinHeapSize();
+
+    @Input
+    @Optional
+    public abstract Property<Integer> getMaxHeapSize();
+
     @Override
     protected void setupBuilder(BuildStrategy builder) {
         builder.setStrict(getStrict().get());
@@ -83,5 +100,8 @@ public abstract class GenerateWasmGCTask extends TeaVMTask {
         builder.setTargetType(TeaVMTargetType.WEBASSEMBLY_GC);
         TaskUtils.applySourceFiles(getSourceFiles(), builder);
         TaskUtils.applySourceFilePolicy(getSourceFilePolicy(), builder);
+        builder.setDirectMallocSupport(getDirectMallocSupport().getOrElse(false));
+        builder.setMinHeapSize(getMinHeapSize().get() * MB);
+        builder.setMaxHeapSize(getMaxHeapSize().get() * MB);
     }
 }