Orion Hodson | 76e6adb | 2018-02-23 13:15:55 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright (C) 2018 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | package transformer; |
| 17 | |
| 18 | import annotations.CalledByIndy; |
| 19 | import annotations.Constant; |
| 20 | import annotations.LinkerFieldHandle; |
| 21 | import annotations.LinkerMethodHandle; |
| 22 | import annotations.MethodHandleKind; |
| 23 | import java.io.InputStream; |
| 24 | import java.io.OutputStream; |
| 25 | import java.lang.invoke.MethodType; |
| 26 | import java.lang.reflect.Method; |
| 27 | import java.lang.reflect.Modifier; |
| 28 | import java.net.URL; |
| 29 | import java.net.URLClassLoader; |
| 30 | import java.nio.file.Files; |
| 31 | import java.nio.file.Path; |
| 32 | import java.nio.file.Paths; |
| 33 | import java.util.HashMap; |
| 34 | import java.util.Map; |
| 35 | import org.objectweb.asm.ClassReader; |
| 36 | import org.objectweb.asm.ClassVisitor; |
| 37 | import org.objectweb.asm.ClassWriter; |
| 38 | import org.objectweb.asm.Handle; |
| 39 | import org.objectweb.asm.MethodVisitor; |
| 40 | import org.objectweb.asm.Opcodes; |
| 41 | import org.objectweb.asm.Type; |
| 42 | |
| 43 | /** |
| 44 | * Class for inserting invoke-dynamic instructions in annotated Java class files. |
| 45 | * |
| 46 | * This class replaces static method invocations of annotated methods |
| 47 | * with invoke-dynamic instructions. Suppose a method is annotated as: |
| 48 | * |
| 49 | * @CalledByIndy( |
| 50 | * invokeMethodHandle = |
| 51 | * @LinkerMethodHandle( |
| 52 | * kind = MethodHandleKind.INVOKE_STATIC, |
| 53 | * enclosingType = TestLinkerMethodMinimalArguments.class, |
| 54 | * argumentTypes = {MethodHandles.Lookup.class, String.class, MethodType.class}, |
| 55 | * name = "linkerMethod" |
| 56 | * ), |
| 57 | * name = "magicAdd", |
| 58 | * returnType = int.class, |
| 59 | * argumentTypes = {int.class, int.class} |
| 60 | * ) |
| 61 | * private int add(int x, int y) { |
| 62 | * throw new UnsupportedOperationException(e); |
| 63 | * } |
| 64 | * |
| 65 | * private int magicAdd(int x, int y) { |
| 66 | * return x + y; |
| 67 | * } |
| 68 | * |
| 69 | * Then invokestatic bytecodes targeting the add() method will be |
| 70 | * replaced invokedynamic instructions targetting the CallSite that is |
| 71 | * construction by the bootstrap method described by the @CalledByIndy |
| 72 | * annotation. |
| 73 | * |
| 74 | * In the example above, this results in add() being replaced by |
| 75 | * invocations of magicAdd(). |
| 76 | */ |
| 77 | class IndyTransformer { |
| 78 | |
| 79 | static class BootstrapBuilder extends ClassVisitor { |
| 80 | |
| 81 | private final Map<String, CalledByIndy> callsiteMap; |
| 82 | private final Map<String, Handle> bsmMap = new HashMap<>(); |
| 83 | |
| 84 | public BootstrapBuilder(int api, Map<String, CalledByIndy> callsiteMap) { |
| 85 | this(api, null, callsiteMap); |
| 86 | } |
| 87 | |
| 88 | public BootstrapBuilder(int api, ClassVisitor cv, Map<String, CalledByIndy> callsiteMap) { |
| 89 | super(api, cv); |
| 90 | this.callsiteMap = callsiteMap; |
| 91 | } |
| 92 | |
| 93 | @Override |
| 94 | public MethodVisitor visitMethod( |
| 95 | int access, String name, String desc, String signature, String[] exceptions) { |
| 96 | MethodVisitor mv = cv.visitMethod(access, name, desc, signature, exceptions); |
| 97 | return new MethodVisitor(this.api, mv) { |
| 98 | @Override |
| 99 | public void visitMethodInsn( |
| 100 | int opcode, String owner, String name, String desc, boolean itf) { |
| 101 | if (opcode == org.objectweb.asm.Opcodes.INVOKESTATIC) { |
| 102 | CalledByIndy callsite = callsiteMap.get(name); |
| 103 | if (callsite != null) { |
| 104 | insertIndy(callsite.name(), desc, callsite); |
| 105 | return; |
| 106 | } |
| 107 | } |
| 108 | mv.visitMethodInsn(opcode, owner, name, desc, itf); |
| 109 | } |
| 110 | |
| 111 | private void insertIndy(String name, String desc, CalledByIndy callsite) { |
| 112 | Handle bsm = buildBootstrapMethodHandle(callsite); |
| 113 | Object[] bsmArgs = buildBootstrapArguments(callsite); |
| 114 | mv.visitInvokeDynamicInsn(name, desc, bsm, bsmArgs); |
| 115 | } |
| 116 | |
| 117 | private Handle buildBootstrapMethodHandle(CalledByIndy callsite) { |
| 118 | MethodHandleKind kind; |
| 119 | if (callsite.fieldMethodHandle().length != 0) { |
| 120 | return buildBootstrapMethodHandleForField(callsite.fieldMethodHandle()[0]); |
| 121 | } else if (callsite.invokeMethodHandle().length != 0) { |
| 122 | return buildBootstrapMethodHandleForMethod( |
| 123 | callsite.invokeMethodHandle()[0]); |
| 124 | } else { |
| 125 | throw new Error("Missing linker method handle in CalledByIndy annotation"); |
| 126 | } |
| 127 | } |
| 128 | |
| 129 | private Handle buildBootstrapMethodHandleForField(LinkerFieldHandle fieldHandle) { |
| 130 | int handleKind; |
| 131 | switch (fieldHandle.kind()) { |
| 132 | case GET_FIELD: |
| 133 | handleKind = Opcodes.H_GETFIELD; |
| 134 | break; |
| 135 | case GET_STATIC: |
| 136 | handleKind = Opcodes.H_GETSTATIC; |
| 137 | break; |
| 138 | case PUT_FIELD: |
| 139 | handleKind = Opcodes.H_PUTFIELD; |
| 140 | break; |
| 141 | case PUT_STATIC: |
| 142 | handleKind = Opcodes.H_PUTSTATIC; |
| 143 | break; |
| 144 | default: |
| 145 | throw new Error("Unknown field invocation kind: " + fieldHandle.kind()); |
| 146 | } |
| 147 | Class<?> resolverClass = fieldHandle.enclosingType(); |
| 148 | String resolverMethod = fieldHandle.name(); |
| 149 | Class<?> resolverReturnType = fieldHandle.type(); |
| 150 | |
| 151 | // TODO: arguments types to invoke resolver with (default + extra args). |
| 152 | throw new Error("WIP"); |
| 153 | } |
| 154 | |
| 155 | private Handle buildBootstrapMethodHandleForMethod( |
| 156 | LinkerMethodHandle methodHandle) { |
| 157 | int handleKind; |
| 158 | switch (methodHandle.kind()) { |
| 159 | case INVOKE_CONSTRUCTOR: |
| 160 | handleKind = Opcodes.H_NEWINVOKESPECIAL; |
| 161 | break; |
| 162 | case INVOKE_INTERFACE: |
| 163 | handleKind = Opcodes.H_INVOKEINTERFACE; |
| 164 | break; |
| 165 | case INVOKE_SPECIAL: |
| 166 | handleKind = Opcodes.H_INVOKESPECIAL; |
| 167 | break; |
| 168 | case INVOKE_STATIC: |
| 169 | handleKind = Opcodes.H_INVOKESTATIC; |
| 170 | break; |
| 171 | case INVOKE_VIRTUAL: |
| 172 | handleKind = Opcodes.H_INVOKEVIRTUAL; |
| 173 | break; |
| 174 | default: |
| 175 | throw new Error( |
| 176 | "Unknown method invocation kind: " + methodHandle.kind()); |
| 177 | } |
| 178 | String className = Type.getInternalName(methodHandle.enclosingType()); |
| 179 | String methodName = methodHandle.name(); |
| 180 | String methodType = |
| 181 | MethodType.methodType( |
| 182 | methodHandle.returnType(), methodHandle.argumentTypes()) |
| 183 | .toMethodDescriptorString(); |
| 184 | return new Handle( |
| 185 | handleKind, className, methodName, methodType, false /* itf */); |
| 186 | } |
| 187 | |
| 188 | private Object decodeConstant(int index, Constant constant) { |
| 189 | if (constant.booleanValue().length == 1) { |
| 190 | return constant.booleanValue()[0]; |
| 191 | } else if (constant.byteValue().length == 1) { |
| 192 | return constant.byteValue()[0]; |
| 193 | } else if (constant.charValue().length == 1) { |
| 194 | return constant.charValue()[0]; |
| 195 | } else if (constant.shortValue().length == 1) { |
| 196 | return constant.shortValue()[0]; |
| 197 | } else if (constant.intValue().length == 1) { |
| 198 | return constant.intValue()[0]; |
| 199 | } else if (constant.longValue().length == 1) { |
| 200 | return constant.longValue()[0]; |
| 201 | } else if (constant.floatValue().length == 1) { |
| 202 | return constant.floatValue()[0]; |
| 203 | } else if (constant.doubleValue().length == 1) { |
| 204 | return constant.doubleValue()[0]; |
| 205 | } else if (constant.stringValue().length == 1) { |
| 206 | return constant.stringValue()[0]; |
| 207 | } else if (constant.classValue().length == 1) { |
| 208 | return Type.getType(constant.classValue()[0]); |
| 209 | } else { |
| 210 | throw new Error("Bad constant at index " + index); |
| 211 | } |
| 212 | } |
| 213 | |
| 214 | private Object[] buildBootstrapArguments(CalledByIndy callsite) { |
| 215 | Constant[] rawArgs = callsite.methodHandleExtraArgs(); |
| 216 | Object[] args = new Object[rawArgs.length]; |
| 217 | for (int i = 0; i < rawArgs.length; ++i) { |
| 218 | args[i] = decodeConstant(i, rawArgs[i]); |
| 219 | } |
| 220 | return args; |
| 221 | } |
| 222 | }; |
| 223 | } |
| 224 | } |
| 225 | |
| 226 | private static void transform(Path inputClassPath, Path outputClassPath) throws Throwable { |
| 227 | URLClassLoader classLoader = |
| 228 | new URLClassLoader( |
| 229 | new URL[] {inputClassPath.toUri().toURL()}, |
| 230 | ClassLoader.getSystemClassLoader()); |
| 231 | String inputClassName = inputClassPath.getFileName().toString().replace(".class", ""); |
| 232 | Class<?> inputClass = classLoader.loadClass(inputClassName); |
| 233 | Map<String, CalledByIndy> callsiteMap = new HashMap<>(); |
| 234 | |
| 235 | for (Method m : inputClass.getDeclaredMethods()) { |
| 236 | CalledByIndy calledByIndy = m.getAnnotation(CalledByIndy.class); |
| 237 | if (calledByIndy == null) { |
| 238 | continue; |
| 239 | } |
| 240 | if (calledByIndy.name() == null) { |
| 241 | throw new Error("CallByIndy annotation does not specify name"); |
| 242 | } |
| 243 | final int PRIVATE_STATIC = Modifier.STATIC | Modifier.PRIVATE; |
| 244 | if ((m.getModifiers() & PRIVATE_STATIC) != PRIVATE_STATIC) { |
| 245 | throw new Error( |
| 246 | "Method whose invocations should be replaced should be private and static"); |
| 247 | } |
| 248 | callsiteMap.put(m.getName(), calledByIndy); |
| 249 | } |
| 250 | ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_FRAMES); |
| 251 | try (InputStream is = Files.newInputStream(inputClassPath)) { |
| 252 | ClassReader cr = new ClassReader(is); |
| 253 | cr.accept(new BootstrapBuilder(Opcodes.ASM6, cw, callsiteMap), 0); |
| 254 | } |
| 255 | try (OutputStream os = Files.newOutputStream(outputClassPath)) { |
| 256 | os.write(cw.toByteArray()); |
| 257 | } |
| 258 | } |
| 259 | |
| 260 | public static void main(String[] args) throws Throwable { |
| 261 | transform(Paths.get(args[0]), Paths.get(args[1])); |
| 262 | } |
| 263 | } |