Java Code Examples for org.objectweb.asm.MethodVisitor

private byte[] getByteCodeForClassWithoutSuperName() {
    ClassWriter classWriter = new ClassWriter(0);
    MethodVisitor methodVisitor;

    classWriter.visit(V10, ACC_PUBLIC | ACC_SUPER, "b/Main", null, null, null);

    classWriter.visitSource("Main.java", null);
    {
        methodVisitor = classWriter.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
        methodVisitor.visitCode();
        Label label0 = new Label();
        methodVisitor.visitLabel(label0);
        methodVisitor.visitLineNumber(3, label0);
        methodVisitor.visitVarInsn(ALOAD, 0);
        methodVisitor.visitMethodInsn(INVOKESPECIAL, "java/lang/Object", "<init>", "()V", false);
        methodVisitor.visitInsn(RETURN);
        methodVisitor.visitMaxs(1, 1);
        methodVisitor.visitEnd();
    }
    classWriter.visitEnd();

    return classWriter.toByteArray();
}
 

@Override
void compile(final MethodVisitor mv) {
    // 编译e1
    e1.compile(mv);
    // 判断测试，e1是否为false
    mv.visitInsn(DUP);
    Label end = new Label();
    mv.visitJumpInsn(IFEQ, end);
    // e1为true的情况: e1 && e2 is equal to e2
    mv.visitInsn(POP);
    e2.compile(mv);
    // e1为假的情况： e1 && e2 is equal to e1:
    // 我们直接跳到这个标签，而不计算e2
    // e2是否需要计算取决于e1
    mv.visitLabel(end);
}
 

public static void boxIfPrimative(MethodVisitor mv, String desc) {
	if( desc.startsWith("L") || desc.startsWith("[")){//object or array - do nothing
		return;
	}
	else{
		switch(desc){
			case "Z": mv.visitFieldInsn(INVOKESTATIC, "java/lang/Boolean", "valueOf", "(Z)Ljava/lang/Boolean;"); break;
			case "B": mv.visitFieldInsn(INVOKESTATIC, "java/lang/Byte", "valueOf", "(B)Ljava/lang/Byte;"); break;
			case "C": mv.visitFieldInsn(INVOKESTATIC, "java/lang/Character", "valueOf", "(C)Ljava/lang/Character;"); break;
			case "S": mv.visitFieldInsn(INVOKESTATIC, "java/lang/Integer", "valueOf", "(S)Ljava/lang/Integer;"); break;//TODO: short is wrong who cares
			case "I": mv.visitFieldInsn(INVOKESTATIC, "java/lang/Integer", "valueOf", "(I)Ljava/lang/Integer;"); break;
			case "J": mv.visitFieldInsn(INVOKESTATIC, "java/lang/Long", "valueOf", "(J)Ljava/lang/Long;"); break;
			case "F": mv.visitFieldInsn(INVOKESTATIC, "java/lang/Float", "valueOf", "(F)Ljava/lang/Float;"); break;
			case "D": mv.visitFieldInsn(INVOKESTATIC, "java/lang/Double", "valueOf", "(D)Ljava/lang/Double;"); break;
		}
	}		
}
 

@Override
void compile(final MethodVisitor mv) {
    // compiles e1
    e1.compile(mv);
    // tests if e1 is true
    mv.visitInsn(DUP);
    // convert to a boolean
    mv.visitInvokeDynamicInsn("asBoolean", "(Ljava/lang/Object;)Z", UNARY);
    Label end = new Label();
    mv.visitJumpInsn(IFNE, end);
    // case where e1 is false : e1 || e2 is equal to e2
    mv.visitInsn(POP);
    e2.compile(mv);
    // if e1 is true, e1 || e2 is equal to e1:
    // we jump directly to this label, without evaluating e2
    mv.visitLabel(end);
}
 

private void writeCaseStatement(final CaseStatement statement, final int switchVariableIndex, final Label thisLabel, final Label nextLabel) {
    controller.getAcg().onLineNumber(statement, "visitCaseStatement");
    MethodVisitor mv = controller.getMethodVisitor();
    OperandStack operandStack = controller.getOperandStack();

    mv.visitVarInsn(ALOAD, switchVariableIndex);

    statement.getExpression().visit(controller.getAcg());
    operandStack.box();
    controller.getBinaryExpressionHelper().getIsCaseMethod().call(mv);
    operandStack.replace(ClassHelper.boolean_TYPE);

    Label l0 = controller.getOperandStack().jump(IFEQ);

    mv.visitLabel(thisLabel);

    statement.getCode().visit(controller.getAcg());

    // now if we don't finish with a break we need to jump past the next comparison
    if (nextLabel != null) {
        mv.visitJumpInsn(GOTO, nextLabel);
    }

    mv.visitLabel(l0);
}
 

@Override
public MethodVisitor visitMethod(final int access, final String name, final String desc, final String signature, final String[] exceptions) {
  if ((access & Opcodes.ACC_SYNTHETIC) != 0) {
    cp.newUTF8("Synthetic");
  }
  if ((access & Opcodes.ACC_DEPRECATED) != 0) {
    cp.newUTF8("Deprecated");
  }
  cp.newUTF8(name);
  cp.newUTF8(desc);
  if (signature != null) {
    cp.newUTF8("Signature");
    cp.newUTF8(signature);
  }
  if (exceptions != null) {
    cp.newUTF8("Exceptions");
    for (int i = 0; i < exceptions.length; ++i) {
      cp.newClass(exceptions[i]);
    }
  }
  return new MethodConstantsCollector(cv.visitMethod(access, name, desc, signature, exceptions), cp);
}
 

@Test
public void testOr() {
    TestMethodBuilder builder = new TestMethodBuilder("test_mth", "(ZZ)V");
    MethodVisitor mv = builder.getGenerator();
    Label start = new Label();
    mv.visitLabel(start);
    Label ret = new Label();
    Label body = new Label();
    mv.visitVarInsn(ILOAD, 0);
    mv.visitJumpInsn(IFNE, body);
    mv.visitVarInsn(ILOAD, 1);
    mv.visitJumpInsn(IFEQ, ret);
    mv.visitLabel(body);
    mv.visitMethodInsn(INVOKESTATIC, THIS_TYPE.getInternalName(), "body", "()V", false);
    mv.visitLabel(ret);
    mv.visitInsn(RETURN);
    mv.visitLocalVariable("a", "Z", null, start, ret, 0);
    mv.visitLocalVariable("b", "Z", null, start, ret, 1);

    String insn = TestHelper.getAsString(builder.finish(), "test_mth");
    String good = "if (a || b) {\n"
            + "    org.spongepowered.test.decompile.IfTests.body();\n"
            + "}";
    Assert.assertEquals(good, insn);
}
 

/**
 * {@inheritDoc}
 */
public Size apply(MethodVisitor methodVisitor, Implementation.Context implementationContext) {
    TypeDescription auxiliaryType = implementationContext.register(PrivilegedMemberLookupAction.of(methodDescription));
    return new Compound(
            TypeCreation.of(auxiliaryType),
            Duplication.SINGLE,
            ClassConstant.of(methodDescription.getDeclaringType()),
            methodName,
            ArrayFactory.forType(TypeDescription.Generic.OfNonGenericType.CLASS)
                    .withValues(typeConstantsFor(methodDescription.getParameters().asTypeList().asErasures())),
            MethodInvocation.invoke(auxiliaryType.getDeclaredMethods().filter(isConstructor()).getOnly()),
            MethodInvocation.invoke(DO_PRIVILEGED),
            TypeCasting.to(TypeDescription.ForLoadedType.of(methodDescription.isConstructor()
                    ? Constructor.class
                    : Method.class))
    ).apply(methodVisitor, implementationContext);
}
 

@Override
public MethodVisitor visitMethod(
    final int access,
    final String name,
    final String descriptor,
    final String signature,
    final String[] exceptions) {
  MethodVisitor methodVisitor;
  if ("<clinit>".equals(name)) {
    int newAccess = Opcodes.ACC_PRIVATE + Opcodes.ACC_STATIC;
    String newName = renamedClinitMethodPrefix + numClinitMethods++;
    methodVisitor = super.visitMethod(newAccess, newName, descriptor, signature, exceptions);

    if (mergedClinitVisitor == null) {
      mergedClinitVisitor = super.visitMethod(newAccess, name, descriptor, null, null);
    }
    mergedClinitVisitor.visitMethodInsn(Opcodes.INVOKESTATIC, owner, newName, descriptor, false);
  } else {
    methodVisitor = super.visitMethod(access, name, descriptor, signature, exceptions);
  }
  return methodVisitor;
}
 

@Override
public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
	if (Names.renderGameOverlayForge.equals(name, desc)) {
		LogUtil.startMethod(Names.renderGameOverlayForge.getName() + " " + Names.renderGameOverlayForge.getDesc());
		return new PatchRenderGameOverlay(cv.visitMethod(access, name, desc, signature, exceptions));
	}
	if (Names.ingameTick.equals(name, desc)) {
		LogUtil.startMethod(Names.ingameTick.getName() + " " + Names.ingameTick.getDesc());
		return new PatchTick(cv.visitMethod(access, name, desc, signature, exceptions));
	}
	if (Names.renderChatForge.equals(name, desc)) {
		LogUtil.startMethod(Names.renderChatForge.getName() + " " + Names.renderChatForge.getDesc());
		return new PatchChat(cv.visitMethod(access, name, desc, signature, exceptions));
	}
	LogUtil.endMethod();
	return super.visitMethod(access, name, desc, signature, exceptions);
}
 

private static void createConstructor(ClassWriter writer, String clsName, Type targetType, Type baseType) {
	final Type ctorType = Type.getMethodType(Type.VOID_TYPE, targetType);

	MethodVisitor init = writer.visitMethod(Opcodes.ACC_PUBLIC | Opcodes.ACC_SYNTHETIC, "<init>", ctorType.getDescriptor(), null, null);
	init.visitCode();
	init.visitVarInsn(Opcodes.ALOAD, 0);
	init.visitVarInsn(Opcodes.ALOAD, 1);
	init.visitInsn(Opcodes.DUP2);
	init.visitMethodInsn(Opcodes.INVOKESPECIAL, baseType.getInternalName(), "<init>", SUPER_CTOR_TYPE.getDescriptor(), false);
	init.visitFieldInsn(Opcodes.PUTFIELD, clsName, CommonMethodsBuilder.TARGET_FIELD_NAME, targetType.getDescriptor());
	init.visitInsn(Opcodes.RETURN);

	init.visitMaxs(0, 0);

	init.visitEnd();
}
 

@Test
public void testExplicitTypeInitializer() throws Exception {
    assertThat(createPlain()
            .defineField(FOO, String.class, Ownership.STATIC, Visibility.PUBLIC)
            .initializer(new ByteCodeAppender() {
                public Size apply(MethodVisitor methodVisitor, Implementation.Context implementationContext, MethodDescription instrumentedMethod) {
                    return new Size(new StackManipulation.Compound(
                            new TextConstant(FOO),
                            FieldAccess.forField(instrumentedMethod.getDeclaringType().getDeclaredFields().filter(named(FOO)).getOnly()).write()
                    ).apply(methodVisitor, implementationContext).getMaximalSize(), instrumentedMethod.getStackSize());
                }
            }).make()
            .load(ClassLoadingStrategy.BOOTSTRAP_LOADER, ClassLoadingStrategy.Default.WRAPPER)
            .getLoaded()
            .getDeclaredField(FOO)
            .get(null), is((Object) FOO));
}
 

private void loadThis(final VariableExpression thisOrSuper) {
    MethodVisitor mv = controller.getMethodVisitor();
    mv.visitVarInsn(ALOAD, 0);
    if (controller.isInGeneratedFunction() && !controller.getCompileStack().isImplicitThis()) {
        mv.visitMethodInsn(INVOKEVIRTUAL, "groovy/lang/Closure", "getThisObject", "()Ljava/lang/Object;", false);
        ClassNode expectedType = controller.getTypeChooser().resolveType(thisOrSuper, controller.getOutermostClass());
        if (!ClassHelper.OBJECT_TYPE.equals(expectedType) && !ClassHelper.isPrimitiveType(expectedType)) {
            BytecodeHelper.doCast(mv, expectedType);
            controller.getOperandStack().push(expectedType);
        } else {
            controller.getOperandStack().push(ClassHelper.OBJECT_TYPE);
        }
    } else {
        controller.getOperandStack().push(controller.getClassNode());
    }
}
 

@Override
public void invokeSpecial(final Class<?> clazz, final List<BytecodeExpression> arguments) {
    final Type[] args = new Type[arguments.size()];
    for (int i = 0; i < arguments.size(); ++i) {
        args[i] = arguments.get(i).getType().getJVMType();
    }
    unit.setSuperInit(
            new BytecodeSequence() {
                @Override
                public void generate(CodeEmitter code) {
                    code.exec(code.getLocal("this"));
                    for (BytecodeExpression e : arguments) {
                        code.exec(e);
                    }
                    MethodVisitor mv = code.getMethodVisitor();
                    mv.visitMethodInsn(Opcodes.INVOKESPECIAL, Type.getInternalName(clazz), "<init>", Type.getMethodDescriptor(Type.VOID_TYPE, args), false);
                }
            }
    );
}
 

@Override
public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
	if (Names.renderGameOverlayForge.equals(name, desc)) {
		LogUtil.startMethod(Names.renderGameOverlayForge.getName() + " " + Names.renderGameOverlayForge.getDesc());
		return new PatchRenderGameOverlay(cv.visitMethod(access, name, desc, signature, exceptions));
	}
	if (Names.ingameTick.equals(name, desc)) {
		LogUtil.startMethod(Names.ingameTick.getName() + " " + Names.ingameTick.getDesc());
		return new PatchTick(cv.visitMethod(access, name, desc, signature, exceptions));
	}
	if (Names.renderChatForge.equals(name, desc)) {
		LogUtil.startMethod(Names.renderChatForge.getName() + " " + Names.renderChatForge.getDesc());
		return new PatchChat(cv.visitMethod(access, name, desc, signature, exceptions));
	}
	LogUtil.endMethod();
	return super.visitMethod(access, name, desc, signature, exceptions);
}
 

@Test
public void testWhileInverse() {
    TestMethodBuilder builder = new TestMethodBuilder("test_mth", "(I)V");
    MethodVisitor mv = builder.getGenerator();
    Label start = new Label();
    mv.visitLabel(start);
    Label end = new Label();
    Label l1 = new Label();
    Label l2 = new Label();
    mv.visitJumpInsn(GOTO, l2);
    mv.visitLabel(l1);
    mv.visitMethodInsn(INVOKESTATIC, THIS_TYPE.getInternalName(), "body", "()V", false);
    mv.visitLabel(l2);
    mv.visitVarInsn(ILOAD, 0);
    mv.visitInsn(ICONST_5);
    mv.visitJumpInsn(IF_ICMPLT, l1);
    mv.visitLabel(end);
    mv.visitInsn(RETURN);
    mv.visitLocalVariable("i", "I", null, start, end, 0);

    String insn = TestHelper.getAsString(builder.finish(), "test_mth");
    String good = "while (i < 5) {\n"
            + "    org.spongepowered.test.decompile.WhileTests.body();\n"
            + "}";
    Assert.assertEquals(good, insn);
}
 

@Test
public void testDecorationWithoutAnnotationRetention() throws Exception {
    Object instance = new ByteBuddy()
            .with(AnnotationRetention.DISABLED)
            .decorate(Foo.class)
            .annotateType(AnnotationDescription.Builder.ofType(Qux.class).build())
            .ignoreAlso(new LatentMatcher.Resolved<MethodDescription>(none()))
            .visit(new AsmVisitorWrapper.ForDeclaredMethods()
                    .method(named(FOO), new AsmVisitorWrapper.ForDeclaredMethods.MethodVisitorWrapper() {
                        public MethodVisitor wrap(TypeDescription instrumentedType,
                                                  MethodDescription instrumentedMethod,
                                                  MethodVisitor methodVisitor,
                                                  Implementation.Context implementationContext,
                                                  TypePool typePool,
                                                  int writerFlags,
                                                  int readerFlags) {
                            return new MethodVisitor(OpenedClassReader.ASM_API, methodVisitor) {
                                @Override
                                public void visitLdcInsn(Object value) {
                                    if (FOO.equals(value)) {
                                        value = BAR;
                                    }
                                    super.visitLdcInsn(value);
                                }
                            };
                        }
                    }))
            .make()
            .load(getClass().getClassLoader(), ClassLoadingStrategy.Default.CHILD_FIRST)
            .getLoaded()
            .getConstructor()
            .newInstance();
    assertThat(instance.getClass().getMethod(FOO).invoke(instance), is((Object) BAR));
    assertThat(instance.getClass().isAnnotationPresent(Bar.class), is(true));
    assertThat(instance.getClass().isAnnotationPresent(Qux.class), is(true));
}
 

@Override
public void operate(MethodVisitor mv) {
    if (fieldDefinition.isStatic()) {
        mv.visitFieldInsn(GETSTATIC, fieldDefinition.getOwnerInternalName(), fieldDefinition.getFieldName(), fieldDefinition.getDescriptor());
    } else {
        throw new UnsupportedOperationException();
    }
}
 

@Override
public BytecodeExpression list(Location loc, final List<BytecodeExpression> args) {
    List<TypeWidget> types = Lists.newArrayList();
    for (BytecodeExpression e : args) {
        types.add(e.getType());
    }
    final TypeWidget unified = unify(types).boxed();
    final ListTypeWidget out = new ListTypeWidget(NotNullableTypeWidget.create(unified));
    return new BaseTypeExpression(out) {
        @Override
        public void generate(CodeEmitter code) {
            MethodVisitor mv = code.getMethodVisitor();
            code.exec(out.construct(constant(args.size())));
            for (BytecodeExpression expr : args) {
                Label skip = new Label();
                mv.visitInsn(Opcodes.DUP);
                code.exec(expr);
                final TypeWidget type = expr.getType();
                boolean nullable = code.cast(unified, type, skip);
                mv.visitMethodInsn(Opcodes.INVOKEINTERFACE, Type.getInternalName(Collection.class), "add", Type.getMethodDescriptor(Type.BOOLEAN_TYPE, Type.getType(Object.class)), true);
                if (nullable) {
                    // we're either going to POP the DUPed List OR the result of add
                    mv.visitLabel(skip);
                }
                mv.visitInsn(Opcodes.POP);
            }
        }
    };
}
 

@Override
public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
	if (Names.guiClosed.equals(name, desc)) {
		LogUtil.startMethod(Names.guiClosed.getName() + " " + Names.guiClosed.getDesc());
		return new PatchGuiClosed(cv.visitMethod(access, name, desc, signature, exceptions));
	}
	LogUtil.endMethod();
	return super.visitMethod(access, name, desc, signature, exceptions);
}
 

@Override
public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
	if (Names.guiConnectingInit1.equals(name, desc)) {
		LogUtil.startMethod(Names.guiConnectingInit1.getName() + " " + Names.guiConnectingInit1.getDesc());
		return new PatchInitGui1(cv.visitMethod(access, name, desc, signature, exceptions));
	}
	if (Names.guiConnectingInit2.equals(name, desc)) {
		LogUtil.startMethod(Names.guiConnectingInit2.getName() + " " + Names.guiConnectingInit2.getDesc());
		return new PatchInitGui2(cv.visitMethod(access, name, desc, signature, exceptions));
	}
	LogUtil.endMethod();
	return super.visitMethod(access, name, desc, signature, exceptions);
}
 

OBBNMethodVisitor3(final MethodMutatorFactory factory,
                   final MutationContext context, final MethodInfo info, final MethodVisitor delegateMethodVisitor)  {
    super(ASMVersion.ASM_VERSION, info.getAccess(), info.getMethodDescriptor(), delegateMethodVisitor);
    this.factory = factory;
    this.context = context;
    this.info = info;
}
 

/**
 * Makes the given visitor visit this type annotation.
 *
 * @param methodVisitor the visitor that must visit this annotation.
 * @param visible {@literal true} if the annotation is visible at runtime.
 */
public void accept(final MethodVisitor methodVisitor, final boolean visible) {
  Label[] startLabels = new Label[this.start.size()];
  Label[] endLabels = new Label[this.end.size()];
  int[] indices = new int[this.index.size()];
  for (int i = 0, n = startLabels.length; i < n; ++i) {
    startLabels[i] = this.start.get(i).getLabel();
    endLabels[i] = this.end.get(i).getLabel();
    indices[i] = this.index.get(i);
  }
  accept(
      methodVisitor.visitLocalVariableAnnotation(
          typeRef, typePath, startLabels, endLabels, indices, desc, visible));
}
 

public void onLineNumber(final ASTNode statement, final String message) {
    if (statement == null || statement instanceof BlockStatement) return;

    currentASTNode = statement;
    int line = statement.getLineNumber();
    if (line < 0 || (!ASM_DEBUG && line == controller.getLineNumber())) return;

    controller.setLineNumber(line);
    MethodVisitor mv = controller.getMethodVisitor();
    if (mv != null) {
        Label l = new Label();
        mv.visitLabel(l);
        mv.visitLineNumber(line, l);
    }
}
 

public void emitIntegerSwitch(Map<Integer, Label> labels, Label defaultCase) {
    // TODO: we should see if the labels are dense, and if so use TABLESWITCH
    MethodVisitor mv = getMethodVisitor();
    List<Integer> codes = Lists.newArrayList(labels.keySet());
    Collections.sort(codes);
    int[] k = new int[codes.size()];
    Label[] kl = new Label[codes.size()];
    for (int i = 0; i < k.length; ++i) {
        k[i] = codes.get(i);
        kl[i] = labels.get(i);
    }
    mv.visitLookupSwitchInsn(defaultCase, k, kl);
    mv.visitJumpInsn(GOTO, defaultCase);
}
 

public ArraysRequiringAnalysisMethodNode(final int access,
                                     final String name,
                                     final String descriptor,
                                     final String signature,
                                     final String[] exceptions,
                                     MethodVisitor mv,
                                     String className,
                                     ClassHierarchy hierarchy)
{
    super(Opcodes.ASM6, access, name, descriptor, signature, exceptions);
    this.className = className;
    this.mv = mv;
    this.hierarchy = hierarchy;
}
 

private static void getReference(MethodVisitor methodVisitor,
        Class<?> parameterType,
        int localIndexOfArrayReferenceBaseIndex,
        int arrayReferenceBaseIndexDelta,
        Class<? extends ProxyChannelRingBuffer> backendType) {
    methodVisitor.visitVarInsn(Opcodes.ALOAD, LOCALS_INDEX_THIS);
    loadLocalIndexAndApplyDelta(methodVisitor, localIndexOfArrayReferenceBaseIndex, arrayReferenceBaseIndexDelta);
    readReference(methodVisitor, backendType);
    if (parameterType != Object.class) {
        methodVisitor.visitTypeInsn(Opcodes.CHECKCAST, Type.getInternalName(parameterType));
    }
}
 

@Override
public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
	if (Names.guiClosed.equals(name, desc)) {
		LogUtil.startMethod(Names.guiClosed.getName() + " " + Names.guiClosed.getDesc());
		return new PatchGuiClosed(cv.visitMethod(access, name, desc, signature, exceptions));
	}
	LogUtil.endMethod();
	return super.visitMethod(access, name, desc, signature, exceptions);
}
 

AODMethodVisitor2( final MethodMutatorFactory factory, final MutationContext context, final MethodInfo info,
                   final MethodVisitor delegateMethodVisitor) {
    super(ASMVersion.ASM_VERSION, info.getAccess(), info.getMethodDescriptor(), delegateMethodVisitor);
    this.factory = factory;
    this.context = context;
    this.info = info;
}
 

@Override
public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
	if (Names.guiClosed.equals(name, desc)) {
		LogUtil.startMethod(Names.guiClosed.getName() + " " + Names.guiClosed.getDesc());
		return new PatchGuiClosed(cv.visitMethod(access, name, desc, signature, exceptions));
	}
	LogUtil.endMethod();
	return super.visitMethod(access, name, desc, signature, exceptions);
}