Java Code Examples for org.objectweb.asm.commons.GeneratorAdapter#visitMethodInsn()

private static void defineSuperAccessorMethod(ClassWriter cw, java.lang.reflect.Method method, Type superType,
        String superAccessorMethodSuffix) 
{
    Method originalAsmMethod = Method.getMethod(method);
    Method newAsmMethod = new Method(method.getName() + superAccessorMethodSuffix,
            originalAsmMethod.getReturnType(),
            originalAsmMethod.getArgumentTypes());
    GeneratorAdapter mg = new GeneratorAdapter(Opcodes.ACC_PUBLIC, newAsmMethod, null, null, cw);
    
    mg.visitCode();
    
    // call super method
    mg.loadThis();
    mg.loadArgs();
    mg.visitMethodInsn(Opcodes.INVOKESPECIAL,
            superType.getInternalName(),
            method.getName(),
            Type.getMethodDescriptor(method),
            false);
    mg.returnValue();
    
    // finish the method
    mg.endMethod();
    mg.visitMaxs(10, 10);
    mg.visitEnd();
}
 

/**
 * Generates a standard error exception with message similar to:
 *
 *    String switch could not find 'equals.(Ljava/lang/Object;)Z' with hashcode 0
 *    in com/example/basic/GrandChild
 *
 * @param mv The generator adaptor used to emit the lookup switch code.
 * @param visitedClassName The abstract string trie structure.
 */
void writeMissingMessageWithHash(GeneratorAdapter mv, String visitedClassName) {
    mv.newInstance(STARK_RELOAD_EXCEPTION_TYPE);
    mv.dup();
    mv.push("String switch could not find '%s' with hashcode %s in %s");
    mv.push(3);
    mv.newArray(OBJECT_TYPE);
    mv.dup();
    mv.push(0);
    visitString();
    mv.arrayStore(OBJECT_TYPE);
    mv.dup();
    mv.push(1);
    visitString();
    visitHashMethod(mv);
    mv.visitMethodInsn(
            Opcodes.INVOKESTATIC,
            "java/lang/Integer",
            "valueOf",
            "(I)Ljava/lang/Integer;", false);
    mv.arrayStore(OBJECT_TYPE);
    mv.dup();
    mv.push(2);
    mv.push(visitedClassName);
    mv.arrayStore(OBJECT_TYPE);
    mv.visitMethodInsn(
            Opcodes.INVOKESTATIC,
            "java/lang/String",
            "format",
            "(Ljava/lang/String;[Ljava/lang/Object;)Ljava/lang/String;", false);
    mv.invokeConstructor(STARK_RELOAD_EXCEPTION_TYPE,
            Method.getMethod("void <init> (String)"));
    mv.throwException();
}
 

void writeMissingMessageWithHash(GeneratorAdapter mv, String visitedClassName) {
    mv.newInstance(INSTANT_RELOAD_EXCEPTION_TYPE);
    mv.dup();
    mv.push("int switch could not find %d in %s");
    mv.push(3);
    mv.newArray(OBJECT_TYPE);
    mv.dup();
    mv.push(0);
    visitInt();
    mv.visitMethodInsn(
            Opcodes.INVOKESTATIC,
            "java/lang/Integer",
            "valueOf",
            "(I)Ljava/lang/Integer;", false);
    mv.arrayStore(OBJECT_TYPE);
    mv.dup();
    mv.push(2);
    mv.push(visitedClassName);
    mv.arrayStore(OBJECT_TYPE);
    mv.visitMethodInsn(
            Opcodes.INVOKESTATIC,
            "java/lang/String",
            "format",
            "(Ljava/lang/String;[Ljava/lang/Object;)Ljava/lang/String;", false);
    mv.invokeConstructor(INSTANT_RELOAD_EXCEPTION_TYPE,
            Method.getMethod("void <init> (String)"));
    mv.throwException();
}
 

/**
 * Generates a standard error exception with message similar to:
 *
 *    String switch could not find 'equals.(Ljava/lang/Object;)Z' with hashcode 0
 *    in com/example/basic/GrandChild
 *
 * @param mv The generator adaptor used to emit the lookup switch code.
 * @param visitedClassName The abstract string trie structure.
 */
void writeMissingMessageWithHash(GeneratorAdapter mv, String visitedClassName) {
    mv.newInstance(INSTANT_RELOAD_EXCEPTION_TYPE);
    mv.dup();
    mv.push("String switch could not find '%s' with hashcode %s in %s");
    mv.push(3);
    mv.newArray(OBJECT_TYPE);
    mv.dup();
    mv.push(0);
    visitString();
    mv.arrayStore(OBJECT_TYPE);
    mv.dup();
    mv.push(1);
    visitString();
    visitHashMethod(mv);
    mv.visitMethodInsn(
            Opcodes.INVOKESTATIC,
            "java/lang/Integer",
            "valueOf",
            "(I)Ljava/lang/Integer;", false);
    mv.arrayStore(OBJECT_TYPE);
    mv.dup();
    mv.push(2);
    mv.push(visitedClassName);
    mv.arrayStore(OBJECT_TYPE);
    mv.visitMethodInsn(
            Opcodes.INVOKESTATIC,
            "java/lang/String",
            "format",
            "(Ljava/lang/String;[Ljava/lang/Object;)Ljava/lang/String;", false);
    mv.invokeConstructor(INSTANT_RELOAD_EXCEPTION_TYPE,
            Method.getMethod("void <init> (String)"));
    mv.throwException();
}
 

@Override
public void visitEnd() {
    if (onBeforeMethodVisitor != null) {
        int access = onBeforeMethodVisitor.access;
        String name = onBeforeMethodVisitor.name;
        String descriptor = "(Z" + onBeforeMethodVisitor.descriptor.substring(1);
        String signature = onBeforeMethodVisitor.signature;
        String[] exceptions = onBeforeMethodVisitor.exceptions;
        GeneratorAdapter mv = new GeneratorAdapter(
                cw.visitMethod(access, name, descriptor, signature, exceptions), access, name,
                descriptor);
        mv.visitCode();
        mv.visitVarInsn(ILOAD, 0);
        Label endWithDefaultLabel = new Label();
        mv.visitJumpInsn(IFEQ, endWithDefaultLabel);
        mv.loadArgs(1, mv.getArgumentTypes().length - 1);
        mv.visitMethodInsn(INVOKESTATIC, checkNotNull(className), name,
                onBeforeMethodVisitor.descriptor, false);
        mv.returnValue();

        mv.visitLabel(endWithDefaultLabel);
        mv.visitFrame(F_NEW, 0, new Object[0], 0, new Object[0]);
        if (mv.getReturnType().getSort() != Type.VOID) {
            // return value will be ignored when !enabled, but need to return something
            WeavingMethodVisitor.pushDefault(mv, mv.getReturnType());
        }
        mv.returnValue();
        mv.endMethod();
    }
    super.visitEnd();
}
 

@Override
protected void doRedirect(GeneratorAdapter mv, int change) {
    mv.loadLocal(change);
    mv.push("init$args." + constructor.args.desc);

    Type arrayType = Type.getType("[Ljava/lang/Object;");
    // init$args args (including this) + locals
    mv.push(types.size() + 1);
    mv.newArray(Type.getType(Object.class));

    int array = mv.newLocal(arrayType);
    mv.dup();
    mv.storeLocal(array);

    // "this" is not ready yet, use null instead.
    mv.dup();
    mv.push(0);
    mv.visitInsn(Opcodes.ACONST_NULL);
    mv.arrayStore(Type.getType(Object.class));

    // Set the arguments in positions 1..(n-1);
    ByteCodeUtils.loadVariableArray(mv, ByteCodeUtils.toLocalVariables(types), 1); // Skip the this value

    // Add the locals array at the last position.
    mv.dup();
    // The index of the last position of the array.
    mv.push(types.size());
    // Create the array with all the local variables declared up to this point.
    ByteCodeUtils.newVariableArray(mv, constructor.variables.subList(0, constructor.localsAtLoadThis));
    mv.arrayStore(Type.getType(Object.class));

    mv.invokeInterface(MonitorVisitor.CHANGE_TYPE, Method.getMethod("Object access$dispatch(String, Object[])"));
    mv.visitTypeInsn(Opcodes.CHECKCAST, "[Ljava/lang/Object;");
    //// At this point, init$args has been called and the result Object is on the stack.
    //// The value of that Object is Object[] with exactly n + 2 elements.
    //// The first element is the resulting local variables
    //// The second element is a string with the qualified name of the constructor to call.
    //// The remaining elements are the constructor arguments.

    // Keep a reference to the new locals array
    mv.dup();
    mv.push(0);
    mv.arrayLoad(Type.getType("[Ljava/lang/Object;"));
    mv.visitTypeInsn(Opcodes.CHECKCAST, "[Ljava/lang/Object;");
    mv.storeLocal(array);

    // Call super constructor
    // Put this behind the returned array
    mv.visitVarInsn(Opcodes.ALOAD, 0);
    mv.swap();
    // Push a null for the marker parameter.
    mv.visitInsn(Opcodes.ACONST_NULL);
    // Invoke the constructor
    mv.visitMethodInsn(Opcodes.INVOKESPECIAL, constructor.owner, "<init>", DISPATCHING_THIS_SIGNATURE, false);

    // Dispatch to init$body
    mv.loadLocal(change);
    mv.push("init$body." + constructor.body.desc);
    mv.loadLocal(array);

    // Now "this" can be set
    mv.dup();
    mv.push(0);
    mv.visitVarInsn(Opcodes.ALOAD, 0);
    mv.arrayStore(Type.getType(Object.class));

    mv.invokeInterface(MonitorVisitor.CHANGE_TYPE, Method.getMethod("Object access$dispatch(String, Object[])"));
    mv.pop();
}
 

@Override
protected void doRedirect(GeneratorAdapter mv, int change) {
    mv.loadLocal(change);
    mv.push("init$args." + constructor.args.desc);

    Type arrayType = Type.getType("[Ljava/lang/Object;");
    // init$args args (including this) + locals
    mv.push(types.size() + 1);
    mv.newArray(Type.getType(Object.class));

    int array = mv.newLocal(arrayType);
    mv.dup();
    mv.storeLocal(array);

    // "this" is not ready yet, use null instead.
    mv.dup();
    mv.push(0);
    mv.visitInsn(Opcodes.ACONST_NULL);
    mv.arrayStore(Type.getType(Object.class));

    // Set the arguments in positions 1..(n-1);
    ByteCodeUtils.loadVariableArray(mv, ByteCodeUtils.toLocalVariables(types), 1); // Skip the this value

    // Add the locals array at the last position.
    mv.dup();
    // The index of the last position of the array.
    mv.push(types.size());
    // Create the array with all the local variables declared up to this point.
    ByteCodeUtils.newVariableArray(mv, constructor.variables.subList(0, constructor.localsAtLoadThis));
    mv.arrayStore(Type.getType(Object.class));

    mv.invokeInterface(TBIncrementalVisitor.ALI_CHANGE_TYPE, Method.getMethod("Object ipc$dispatch(String, Object[])"));
    mv.visitTypeInsn(Opcodes.CHECKCAST, "[Ljava/lang/Object;");
    //// At this point, init$args has been called and the result Object is on the stack.
    //// The value of that Object is Object[] with exactly n + 2 elements.
    //// The first element is the resulting local variables
    //// The second element is a string with the qualified name of the constructor to call.
    //// The remaining elements are the constructor arguments.

    // Keep a reference to the new locals array
    mv.dup();
    mv.push(0);
    mv.arrayLoad(Type.getType("[Ljava/lang/Object;"));
    mv.visitTypeInsn(Opcodes.CHECKCAST, "[Ljava/lang/Object;");
    mv.storeLocal(array);

    // Call super constructor
    // Put this behind the returned array
    mv.visitVarInsn(Opcodes.ALOAD, 0);
    mv.swap();
    // Push a null for the marker parameter.
    mv.visitInsn(Opcodes.ACONST_NULL);
    // Invoke the constructor
    mv.visitMethodInsn(Opcodes.INVOKESPECIAL, constructor.owner, "<init>", DISPATCHING_THIS_SIGNATURE, false);

    // Dispatch to init$body
    mv.loadLocal(change);
    mv.push("init$body." + constructor.body.desc);
    mv.loadLocal(array);

    // Now "this" can be set
    mv.dup();
    mv.push(0);
    mv.visitVarInsn(Opcodes.ALOAD, 0);
    mv.arrayStore(Type.getType(Object.class));

    mv.invokeInterface(TBIncrementalVisitor.ALI_CHANGE_TYPE, Method.getMethod("Object ipc$dispatch(String, Object[])"));
    mv.pop();
}
 

/**
 * 插入代码
 *
 * @param mv
 * @param className
 * @param args
 * @param returnType
 * @param isStatic
 */
public static void createInsertCode(GeneratorAdapter mv, String className, List<Type> args, Type returnType, boolean isStatic, int methodId) {
    prepareMethodParameters(mv, className, args, returnType, isStatic, methodId);
    //开始调用
    mv.visitMethodInsn(Opcodes.INVOKESTATIC,
            PROXYCLASSNAME,
            "proxy",
            "([Ljava/lang/Object;Ljava/lang/Object;" + REDIRECTCLASSNAME + "ZI[Ljava/lang/Class;Ljava/lang/Class;)Lcom/meituan/robust/PatchProxyResult;",
            false);

    int local = mv.newLocal(Type.getType("Lcom/meituan/robust/PatchProxyResult;"));
    mv.storeLocal(local);
    mv.loadLocal(local);

    mv.visitFieldInsn(Opcodes.GETFIELD, "com/meituan/robust/PatchProxyResult", "isSupported", "Z");

    // if isSupported
    Label l1 = new Label();
    mv.visitJumpInsn(Opcodes.IFEQ, l1);

    //判断是否有返回值，代码不同
    if ("V".equals(returnType.getDescriptor())) {
        mv.visitInsn(Opcodes.RETURN);
    } else {
        mv.loadLocal(local);
        mv.visitFieldInsn(Opcodes.GETFIELD, "com/meituan/robust/PatchProxyResult", "result", "Ljava/lang/Object;");
        //强制转化类型
        if (!castPrimateToObj(mv, returnType.getDescriptor())) {
            //这里需要注意，如果是数组类型的直接使用即可，如果非数组类型，就得去除前缀了,还有最终是没有结束符;
            //比如：Ljava/lang/String; ==》 java/lang/String
            String newTypeStr = null;
            int len = returnType.getDescriptor().length();
            if (returnType.getDescriptor().startsWith("[")) {
                newTypeStr = returnType.getDescriptor().substring(0, len);
            } else {
                newTypeStr = returnType.getDescriptor().substring(1, len - 1);
            }
            mv.visitTypeInsn(Opcodes.CHECKCAST, newTypeStr);
        }

        //这里还需要做返回类型不同返回指令也不同
        mv.visitInsn(getReturnTypeCode(returnType.getDescriptor()));
    }

    mv.visitLabel(l1);
}
 

@Override
protected void restore(GeneratorAdapter mv, List<Type> args) {
    // At this point, init$args has been called and the result Object is on the stack.
    // The value of that Object is Object[] with exactly n + 1 elements.
    // The first element is a string with the qualified name of the constructor to call.
    // The remaining elements are the constructtor arguments.

    // Create a new local that holds the result of init$args call.
    mv.visitTypeInsn(Opcodes.CHECKCAST, "[Ljava/lang/Object;");
    int constructorArgs = mv.newLocal(Type.getType("[Ljava/lang/Object;"));
    mv.storeLocal(constructorArgs);

    // Reinstate local values
    mv.loadLocal(locals);
    int stackIndex = 0;
    for (int arrayIndex = 0; arrayIndex < args.size(); arrayIndex++) {
        Type arg = args.get(arrayIndex);
        // Do not restore "this"
        if (arrayIndex > 0) {
            // duplicates the array
            mv.dup();
            // index in the array of objects to restore the boxed parameter.
            mv.push(arrayIndex);
            // get it from the array
            mv.arrayLoad(Type.getType(Object.class));
            // unbox the argument
            ByteCodeUtils.unbox(mv, arg);
            // restore the argument
            mv.visitVarInsn(arg.getOpcode(Opcodes.ISTORE), stackIndex);
        }
        // stack index must progress according to the parameter type we just processed.
        stackIndex += arg.getSize();
    }
    // pops the array
    mv.pop();

    // Push a null for the marker parameter.
    mv.loadLocal(constructorArgs);
    mv.visitInsn(Opcodes.ACONST_NULL);

    // Invoke the constructor
    mv.visitMethodInsn(Opcodes.INVOKESPECIAL, thisClassName, "<init>", DISPATCHING_THIS_SIGNATURE, false);

    mv.goTo(end.getLabel());
}