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package org.graalvm.compiler.bytecode;

import static org.graalvm.compiler.bytecode.Bytecodes.ATHROW;
import static org.graalvm.compiler.bytecode.Bytecodes.INVOKEINTERFACE;
import static org.graalvm.compiler.bytecode.Bytecodes.INVOKESPECIAL;
import static org.graalvm.compiler.bytecode.Bytecodes.INVOKESTATIC;
import static org.graalvm.compiler.bytecode.Bytecodes.INVOKEVIRTUAL;

import java.lang.annotation.Annotation;

import jdk.vm.ci.meta.ConstantPool;
import jdk.vm.ci.meta.ResolvedJavaMethod;

Utilities for working around the absence of method annotations and parameter annotations on
bridge methods where the bridged methods have method annotations or parameter annotations. Not
all Java compilers copy method annotations and parameter annotations to bridge methods.
See Also:
6695379
495396
427745/**
 * Utilities for working around the absence of method annotations and parameter annotations on
 * bridge methods where the bridged methods have method annotations or parameter annotations. Not
 * all Java compilers copy method annotations and parameter annotations to bridge methods.
 *
 * @see <a href="http://bugs.java.com/view_bug.do?bug_id=6695379">6695379</a>
 * @see <a href="https://bugs.eclipse.org/bugs/show_bug.cgi?id=495396">495396</a>
 * @see <a href="https://bugs.eclipse.org/bugs/show_bug.cgi?id=427745">427745</a>
 */
public class BridgeMethodUtils {

    
Gets the method bridged to by a bridge method. The value returned is the method called by method that has the same name as bridge. 
Params:
bridge – a bridge method
Returns:
the method called by bridge whose name is the same as bridge.getName()/**
     * Gets the method bridged to by a {@linkplain ResolvedJavaMethod#isBridge() bridge} method. The
     * value returned is the method called by {@code method} that has the same name as
     * {@code bridge}.
     *
     * @param bridge a bridge method
     * @return the method called by {@code bridge} whose name is the same as
     *         {@code bridge.getName()}
     */
    public static ResolvedJavaMethod getBridgedMethod(ResolvedJavaMethod bridge) {
        assert bridge.isBridge();
        Bytecode code = new ResolvedJavaMethodBytecode(bridge);
        BytecodeStream stream = new BytecodeStream(code.getCode());
        int opcode = stream.currentBC();
        ResolvedJavaMethod bridged = null;
        boolean calledAbstractMethodErrorConstructor = false;
        while (opcode != Bytecodes.END) {
            switch (opcode) {
                case INVOKEVIRTUAL:
                case INVOKESPECIAL:
                case INVOKESTATIC:
                case INVOKEINTERFACE: {
                    int cpi = stream.readCPI();
                    ConstantPool cp = code.getConstantPool();
                    cp.loadReferencedType(cpi, opcode);
                    ResolvedJavaMethod method = (ResolvedJavaMethod) cp.lookupMethod(cpi, opcode);
                    if (method.getName().equals(bridge.getName())) {
                        if (!assertionsEnabled()) {
                            return method;
                        }
                        assert bridged == null || bridged.equals(method) : String.format("Found calls to different methods named %s in bridge method %s%n  callee 1: %s%n  callee 2: %s",
                                        bridge.getName(), bridge.format("%R %H.%n(%P)"), bridged.format("%R %H.%n(%P)"), method.format("%R %H.%n(%P)"));
                        bridged = method;
                    } else if (method.getName().equals("<init>") && method.getDeclaringClass().getName().equals("Ljava/lang/AbstractMethodError;")) {
                        calledAbstractMethodErrorConstructor = true;
                    }
                    break;
                }
                case ATHROW: {
                    if (calledAbstractMethodErrorConstructor) {
                        // This is a miranda method
                        return null;
                    }
                }
            }
            stream.next();
            opcode = stream.currentBC();
        }
        if (bridged == null) {
            String dis = new BytecodeDisassembler().disassemble(bridge);
            throw new InternalError(String.format("Couldn't find method bridged by %s:%n%s", bridge.format("%R %H.%n(%P)"), dis));
        }
        return bridged;
    }

    @SuppressWarnings("all")
    private static boolean assertionsEnabled() {
        boolean enabled = false;
        assert enabled = true;
        return enabled;
    }

    
A helper for AnnotatedElement.getAnnotation(Class<Annotation>) that handles the absence of annotations on bridge methods where the bridged method has annotations. /**
     * A helper for {@link ResolvedJavaMethod#getAnnotation(Class)} that handles the absence of
     * annotations on bridge methods where the bridged method has annotations.
     */
    public static <T extends Annotation> T getAnnotation(Class<T> annotationClass, ResolvedJavaMethod method) {
        T a = method.getAnnotation(annotationClass);
        if (a == null && method.isBridge()) {
            ResolvedJavaMethod bridged = getBridgedMethod(method);
            if (bridged != null) {
                a = bridged.getAnnotation(annotationClass);
            }
        }
        return a;
    }

    
A helper for AnnotatedElement.getAnnotations() that handles the absence of annotations on bridge methods where the bridged method has annotations. /**
     * A helper for {@link ResolvedJavaMethod#getAnnotations()} that handles the absence of
     * annotations on bridge methods where the bridged method has annotations.
     */
    public static Annotation[] getAnnotations(ResolvedJavaMethod method) {
        Annotation[] a = method.getAnnotations();
        if (a.length == 0 && method.isBridge()) {
            ResolvedJavaMethod bridged = getBridgedMethod(method);
            if (bridged != null) {
                a = bridged.getAnnotations();
            }
        }
        return a;
    }

    
A helper for AnnotatedElement.getDeclaredAnnotations() that handles the absence of annotations on bridge methods where the bridged method has annotations. /**
     * A helper for {@link ResolvedJavaMethod#getDeclaredAnnotations()} that handles the absence of
     * annotations on bridge methods where the bridged method has annotations.
     */
    public static Annotation[] getDeclaredAnnotations(ResolvedJavaMethod method) {
        Annotation[] a = method.getAnnotations();
        if (a.length == 0 && method.isBridge()) {
            ResolvedJavaMethod bridged = getBridgedMethod(method);
            if (bridged != null) {
                a = bridged.getDeclaredAnnotations();
            }
        }
        return a;
    }

    
A helper for ResolvedJavaMethod.getParameterAnnotations() that handles the absence of parameter annotations on bridge methods where the bridged method has parameter annotations. /**
     * A helper for {@link ResolvedJavaMethod#getParameterAnnotations()} that handles the absence of
     * parameter annotations on bridge methods where the bridged method has parameter annotations.
     */
    public static Annotation[][] getParameterAnnotations(ResolvedJavaMethod method) {
        Annotation[][] a = method.getParameterAnnotations();
        if (a.length == 0 && method.isBridge()) {
            ResolvedJavaMethod bridged = getBridgedMethod(method);
            if (bridged != null) {
                a = bridged.getParameterAnnotations();
            }
        }
        return a;
    }

    
A helper for ResolvedJavaMethod.getParameterAnnotation(Class<Annotation>, int) that handles the absence of parameter annotations on bridge methods where the bridged method has parameter annotations. /**
     * A helper for {@link ResolvedJavaMethod#getParameterAnnotation(Class, int)} that handles the
     * absence of parameter annotations on bridge methods where the bridged method has parameter
     * annotations.
     */
    public static <T extends Annotation> T getParameterAnnotation(Class<T> annotationClass, int parameterIndex, ResolvedJavaMethod method) {
        T a = method.getParameterAnnotation(annotationClass, parameterIndex);
        if (a == null && method.isBridge()) {
            ResolvedJavaMethod bridged = getBridgedMethod(method);
            if (bridged != null) {
                a = bridged.getParameterAnnotation(annotationClass, parameterIndex);
            }
        }
        return a;
    }
}