1/*
2 * Copyright (c) 2014, 2017, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23package jdk.vm.ci.hotspot;
24
25import static jdk.vm.ci.hotspot.CompilerToVM.compilerToVM;
26import static jdk.vm.ci.hotspot.HotSpotJVMCIRuntime.runtime;
27
28import java.lang.invoke.MethodHandle;
29import java.util.Objects;
30
31import jdk.vm.ci.common.JVMCIError;
32import jdk.vm.ci.meta.ConstantReflectionProvider;
33import jdk.vm.ci.meta.JavaConstant;
34import jdk.vm.ci.meta.MethodHandleAccessProvider;
35import jdk.vm.ci.meta.ResolvedJavaField;
36import jdk.vm.ci.meta.ResolvedJavaMethod;
37import jdk.vm.ci.meta.ResolvedJavaType;
38
39public class HotSpotMethodHandleAccessProvider implements MethodHandleAccessProvider {
40
41    private final ConstantReflectionProvider constantReflection;
42
43    public HotSpotMethodHandleAccessProvider(ConstantReflectionProvider constantReflection) {
44        this.constantReflection = constantReflection;
45    }
46
47    /**
48     * Lazy initialization to break class initialization cycle. Field and method lookup is only
49     * possible after the {@link HotSpotJVMCIRuntime} is fully initialized.
50     */
51    static class LazyInitialization {
52        static final ResolvedJavaType lambdaFormType;
53        static final ResolvedJavaField methodHandleFormField;
54        static final ResolvedJavaField lambdaFormVmentryField;
55        static final ResolvedJavaField methodField;
56        static final HotSpotResolvedJavaField vmtargetField;
57
58        /**
59         * Search for an instance field with the given name in a class.
60         *
61         * @param declaringType the type declaring the field
62         * @param fieldName name of the field to be searched
63         * @param fieldType resolved Java type of the field
64         * @return resolved Java field
65         * @throws NoSuchFieldError
66         */
67        private static ResolvedJavaField findFieldInClass(ResolvedJavaType declaringType, String fieldName, ResolvedJavaType fieldType) {
68            ResolvedJavaField[] fields = declaringType.getInstanceFields(false);
69            for (ResolvedJavaField field : fields) {
70                if (field.getName().equals(fieldName) && field.getType().equals(fieldType)) {
71                    return field;
72                }
73            }
74            throw new NoSuchFieldError(fieldType.getName() + " " + declaringType + "." + fieldName);
75        }
76
77        private static ResolvedJavaType resolveType(Class<?> c) {
78            return runtime().fromClass(c);
79        }
80
81        private static ResolvedJavaType resolveType(String className) throws ClassNotFoundException {
82            return resolveType(Class.forName(className));
83        }
84
85        static {
86            try {
87                ResolvedJavaType methodHandleType = resolveType(MethodHandle.class);
88                ResolvedJavaType memberNameType = resolveType("java.lang.invoke.MemberName");
89                lambdaFormType = resolveType("java.lang.invoke.LambdaForm");
90                methodHandleFormField = findFieldInClass(methodHandleType, "form", lambdaFormType);
91                lambdaFormVmentryField = findFieldInClass(lambdaFormType, "vmentry", memberNameType);
92                ResolvedJavaType methodType = resolveType("java.lang.invoke.ResolvedMethodName");
93                methodField = findFieldInClass(memberNameType, "method", methodType);
94                vmtargetField = (HotSpotResolvedJavaField) findFieldInClass(methodType, "vmtarget", resolveType(HotSpotJVMCIRuntime.getHostWordKind().toJavaClass()));
95
96            } catch (Throwable ex) {
97                throw new JVMCIError(ex);
98            }
99        }
100    }
101
102    @Override
103    public IntrinsicMethod lookupMethodHandleIntrinsic(ResolvedJavaMethod method) {
104        int intrinsicId = ((HotSpotResolvedJavaMethodImpl) method).intrinsicId();
105        if (intrinsicId != 0) {
106            return getMethodHandleIntrinsic(intrinsicId);
107        }
108        return null;
109    }
110
111    public static IntrinsicMethod getMethodHandleIntrinsic(int intrinsicId) {
112        HotSpotVMConfig config = runtime().getConfig();
113        if (intrinsicId == config.vmIntrinsicInvokeBasic) {
114            return IntrinsicMethod.INVOKE_BASIC;
115        } else if (intrinsicId == config.vmIntrinsicLinkToInterface) {
116            return IntrinsicMethod.LINK_TO_INTERFACE;
117        } else if (intrinsicId == config.vmIntrinsicLinkToSpecial) {
118            return IntrinsicMethod.LINK_TO_SPECIAL;
119        } else if (intrinsicId == config.vmIntrinsicLinkToStatic) {
120            return IntrinsicMethod.LINK_TO_STATIC;
121        } else if (intrinsicId == config.vmIntrinsicLinkToVirtual) {
122            return IntrinsicMethod.LINK_TO_VIRTUAL;
123        }
124        return null;
125    }
126
127    @Override
128    public ResolvedJavaMethod resolveInvokeBasicTarget(JavaConstant methodHandle, boolean forceBytecodeGeneration) {
129        if (methodHandle.isNull()) {
130            return null;
131        }
132
133        /* Load non-public field: LambdaForm MethodHandle.form */
134        JavaConstant lambdaForm = constantReflection.readFieldValue(LazyInitialization.methodHandleFormField, methodHandle);
135        if (lambdaForm == null || lambdaForm.isNull()) {
136            return null;
137        }
138
139        JavaConstant memberName = constantReflection.readFieldValue(LazyInitialization.lambdaFormVmentryField, lambdaForm);
140        if (memberName.isNull() && forceBytecodeGeneration) {
141            Object lf = ((HotSpotObjectConstant) lambdaForm).asObject(LazyInitialization.lambdaFormType);
142            compilerToVM().compileToBytecode(Objects.requireNonNull(lf));
143            memberName = constantReflection.readFieldValue(LazyInitialization.lambdaFormVmentryField, lambdaForm);
144            assert memberName.isNonNull();
145        }
146        JavaConstant method = constantReflection.readFieldValue(LazyInitialization.methodField, memberName);
147        return getTargetMethod(method);
148    }
149
150    @Override
151    public ResolvedJavaMethod resolveLinkToTarget(JavaConstant memberName) {
152        if (memberName.isNull()) {
153            return null;
154        }
155        JavaConstant method = constantReflection.readFieldValue(LazyInitialization.methodField, memberName);
156        return getTargetMethod(method);
157    }
158
159    /**
160     * Returns the {@link ResolvedJavaMethod} for the method of a java.lang.invoke.MemberName.
161     */
162    private static ResolvedJavaMethod getTargetMethod(JavaConstant method) {
163        if (method == null) {
164            // If readFieldValue returns NULL the type was wrong
165            throw new IllegalArgumentException("unexpected type for memberName");
166        }
167
168        Object object = ((HotSpotObjectConstantImpl) method).object();
169        /* Read the ResolvedJavaMethod from the injected field MemberName.method.vmtarget */
170        return compilerToVM().getResolvedJavaMethod(object, LazyInitialization.vmtargetField.offset());
171    }
172}
173