C backend: make compiled binary independent of load location

core/src/main/java/org/teavm/backend/c/CTarget.java

@@ -53,6 +53,7 @@ import org.teavm.backend.c.intrinsic.PlatformClassIntrinsic;
 import org.teavm.backend.c.intrinsic.PlatformClassMetadataIntrinsic;
 import org.teavm.backend.c.intrinsic.PlatformIntrinsic;
 import org.teavm.backend.c.intrinsic.PlatformObjectIntrinsic;
+import org.teavm.backend.c.intrinsic.RuntimeClassIntrinsic;
 import org.teavm.backend.c.intrinsic.ShadowStackIntrinsic;
 import org.teavm.backend.c.intrinsic.StructureIntrinsic;
 import org.teavm.dependency.ClassDependency;
@@ -231,6 +232,7 @@ public class CTarget implements TeaVMTarget, TeaVMCHost {
         intrinsics.add(new MutatorIntrinsic());
         intrinsics.add(new ExceptionHandlingIntrinsic());
         intrinsics.add(new FunctionIntrinsic(characteristics, exportDependencyListener.getResolvedMethods()));
+        intrinsics.add(new RuntimeClassIntrinsic());
 
         List<Generator> generators = new ArrayList<>();
         generators.add(new ArrayGenerator());

core/src/main/java/org/teavm/backend/c/intrinsic/RuntimeClassIntrinsic.java

@@ -0,0 +1,53 @@
+/*
+ *  Copyright 2018 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.c.intrinsic;
+
+import org.teavm.ast.InvocationExpr;
+import org.teavm.model.MethodReference;
+import org.teavm.runtime.RuntimeClass;
+
+public class RuntimeClassIntrinsic implements Intrinsic {
+    @Override
+    public boolean canHandle(MethodReference method) {
+        if (!method.getClassName().equals(RuntimeClass.class.getName())) {
+            return false;
+        }
+
+        switch (method.getName()) {
+            case "pack":
+            case "unpack":
+                return true;
+            default:
+                return false;
+        }
+    }
+
+    @Override
+    public void apply(IntrinsicContext context, InvocationExpr invocation) {
+        switch (invocation.getMethod().getName()) {
+            case "pack":
+                context.writer().print("PACK_CLASS(");
+                context.emit(invocation.getArguments().get(0));
+                context.writer().print(")");
+                break;
+            case "unpack":
+                context.writer().print("UNPACK_CLASS(");
+                context.emit(invocation.getArguments().get(0));
+                context.writer().print(")");
+                break;
+        }
+    }
+}

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

@@ -52,6 +52,7 @@ import org.teavm.backend.wasm.intrinsics.PlatformClassIntrinsic;
 import org.teavm.backend.wasm.intrinsics.PlatformClassMetadataIntrinsic;
 import org.teavm.backend.wasm.intrinsics.PlatformIntrinsic;
 import org.teavm.backend.wasm.intrinsics.PlatformObjectIntrinsic;
+import org.teavm.backend.wasm.intrinsics.RuntimeClassIntrinsic;
 import org.teavm.backend.wasm.intrinsics.ShadowStackIntrinsic;
 import org.teavm.backend.wasm.intrinsics.StructureIntrinsic;
 import org.teavm.backend.wasm.intrinsics.WasmIntrinsicFactory;
@@ -332,6 +333,7 @@ public class WasmTarget implements TeaVMTarget, TeaVMWasmHost {
         context.addIntrinsic(new PlatformObjectIntrinsic(classGenerator));
         context.addIntrinsic(new PlatformClassMetadataIntrinsic());
         context.addIntrinsic(new ClassIntrinsic());
+        context.addIntrinsic(new RuntimeClassIntrinsic());
         context.addGenerator(new ArrayGenerator());
 
         IntrinsicFactoryContext intrinsicFactoryContext = new IntrinsicFactoryContext();

core/src/main/java/org/teavm/backend/wasm/intrinsics/RuntimeClassIntrinsic.java

@@ -0,0 +1,56 @@
+/*
+ *  Copyright 2018 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;
+
+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.model.MethodReference;
+import org.teavm.runtime.RuntimeClass;
+
+public class RuntimeClassIntrinsic implements WasmIntrinsic {
+    @Override
+    public boolean isApplicable(MethodReference methodReference) {
+        if (!methodReference.getClassName().equals(RuntimeClass.class.getName())) {
+            return false;
+        }
+
+        switch (methodReference.getName()) {
+            case "pack":
+            case "unpack":
+                return true;
+            default:
+                return false;
+        }
+    }
+
+    @Override
+    public WasmExpression apply(InvocationExpr invocation, WasmIntrinsicManager manager) {
+        switch (invocation.getMethod().getName()) {
+            case "pack":
+                return new WasmIntBinary(WasmIntType.INT32, WasmIntBinaryOperation.SHR_UNSIGNED,
+                        manager.generate(invocation.getArguments().get(0)), new WasmInt32Constant(3));
+            case "unpack":
+                return new WasmIntBinary(WasmIntType.INT32, WasmIntBinaryOperation.SHL,
+                        manager.generate(invocation.getArguments().get(0)), new WasmInt32Constant(3));
+            default:
+                throw new AssertionError();
+        }
+    }
+}

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

@@ -28,7 +28,7 @@ public final class Allocator {
     public static Address allocate(RuntimeClass tag) {
         RuntimeObject object = GC.alloc(tag.size);
         fillZero(object.toAddress(), tag.size);
-        object.classReference = tag.toAddress().toInt() >> 3;
+        object.classReference = tag.pack();
         return object.toAddress();
     }
 
@@ -41,7 +41,7 @@ public final class Allocator {
         fillZero(result, sizeInBytes);
 
         RuntimeArray array = result.toStructure();
-        array.classReference = tag.toAddress().toInt() >> 3;
+        array.classReference = tag.pack();
         array.size = size;
 
         return result;

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

@@ -61,6 +61,12 @@ public class RuntimeClass extends RuntimeObject {
 
     @Unmanaged
     public static RuntimeClass getClass(RuntimeObject object) {
-        return Address.fromInt(object.classReference << 3).toStructure();
+        return unpack(object.classReference);
     }
+
+    @Unmanaged
+    public static native RuntimeClass unpack(int n);
+
+    @Unmanaged
+    public final native int pack();
 }

core/src/main/resources/org/teavm/backend/c/runtime.c

@@ -29,8 +29,8 @@ typedef struct JavaArray JavaArray;
 typedef struct JavaClass JavaClass;
 typedef struct JavaString JavaString;
 
-#define PACK_CLASS(cls) ((int32_t) (((uintptr_t) (cls)) >> 3))
+#define PACK_CLASS(cls) ((int32_t) ((uintptr_t) ((char*) (cls) - (char*) &TeaVM_beforeClasses) >> 3))
-#define UNPACK_CLASS(cls) ((JavaClass *) (uintptr_t) (uint32_t) (uintptr_t) (((int64_t*) NULL) + cls))
+#define UNPACK_CLASS(cls) ((JavaClass*) ((char*) &TeaVM_beforeClasses + ((cls) << 3)))
 #define CLASS_OF(obj) (UNPACK_CLASS(((JavaObject*) (obj))->header))
 #define AS(ptr, type) ((type*) (ptr))
 
@@ -106,6 +106,8 @@ static int32_t gc_regionSize = INT32_C(32768);
 static int32_t gc_regionMaxCount = INT32_C(0);
 static int64_t gc_availableBytes = INT64_C(0);
 
+static char TeaVM_beforeClasses[128] = "TEAVM";
+
 static double TeaVM_rand() {
     return rand() / ((double) RAND_MAX + 1);
 }