Add class transformers to convert functions to native

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

@@ -115,6 +115,7 @@
 import org.teavm.backend.wasm.render.WasmCRenderer;
 import org.teavm.backend.wasm.render.WasmRenderer;
 import org.teavm.backend.wasm.runtime.WasmSupport;
+import org.teavm.backend.wasm.transformation.BaseClassesTransformation;
 import org.teavm.backend.wasm.transformation.IndirectCallTraceTransformation;
 import org.teavm.backend.wasm.transformation.MemoryAccessTraceTransformation;
 import org.teavm.backend.wasm.transformation.WasiFileSystemProviderTransformer;
@@ -241,6 +242,7 @@ public VariableCategoryProvider variableCategoryProvider() {
     public List<ClassHolderTransformer> getTransformers() {
         List<ClassHolderTransformer> transformers = new ArrayList<>();
         transformers.add(new ClassPatch());
+        transformers.add(new BaseClassesTransformation());
         transformers.add(new WasmDependencyListener());
         if (runtimeType == WasmRuntimeType.WASI) {
             transformers.add(new WasiSupportClassTransformer());

core/src/main/java/org/teavm/backend/wasm/transformation/BaseClassesTransformation.java

@@ -0,0 +1,41 @@
+/*
+ *  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.transformation;
+
+import org.teavm.model.ClassHolder;
+import org.teavm.model.ClassHolderTransformer;
+import org.teavm.model.ClassHolderTransformerContext;
+import org.teavm.model.ElementModifier;
+
+public class BaseClassesTransformation implements ClassHolderTransformer {
+
+    @Override
+    public void transformClass(ClassHolder cls, ClassHolderTransformerContext context) {
+        if (cls.getName().equals("java.lang.Integer") || cls.getName().equals("java.lang.Long")) {
+            for (var method : cls.getMethods()) {
+                switch (method.getName()) {
+                case "numberOfLeadingZeros":
+                case "numberOfTrailingZeros":
+                case "bitCount":
+                    method.setProgram(null);
+                    method.getModifiers().add(ElementModifier.NATIVE);
+                    break;
+                }
+            }
+        }
+    }
+
+}

core/src/main/java/org/teavm/backend/wasm/transformation/gc/BaseClassesTransformation.java

@@ -121,6 +121,17 @@ public void transformClass(ClassHolder cls, ClassHolderTransformerContext contex
             var clear = cls.getMethod(new MethodDescriptor("clear", void.class));
             clear.getModifiers().add(ElementModifier.NATIVE);
             clear.setProgram(null);
+        } else if (cls.getName().equals("java.lang.Integer") || cls.getName().equals("java.lang.Long")) {
+            for (var method : cls.getMethods()) {
+                switch (method.getName()) {
+                case "numberOfLeadingZeros":
+                case "numberOfTrailingZeros":
+                case "bitCount":
+                    method.setProgram(null);
+                    method.getModifiers().add(ElementModifier.NATIVE);
+                    break;
+                }
+            }
         }
     }