// ASM: a very small and fast Java bytecode manipulation framework // Copyright (c) 2000-2011 INRIA, France Telecom // All rights reserved. // // Redistribution and use in source and binary forms, with or without // modification, are permitted provided that the following conditions // are met: // 1. Redistributions of source code must retain the above copyright // notice, this list of conditions and the following disclaimer. // 2. Redistributions in binary form must reproduce the above copyright // notice, this list of conditions and the following disclaimer in the // documentation and/or other materials provided with the distribution. // 3. Neither the name of the copyright holders nor the names of its // contributors may be used to endorse or promote products derived from // this software without specific prior written permission. // // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE // ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE // LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR // CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF // SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS // INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN // CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) // ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF // THE POSSIBILITY OF SUCH DAMAGE. package org.springframework.asm; /** * A {@link MethodVisitor} that generates a corresponding 'method_info' structure, as defined in the * Java Virtual Machine Specification (JVMS). * * @see JVMS * 4.6 * @author Eric Bruneton * @author Eugene Kuleshov */ final class MethodWriter extends MethodVisitor { /** Indicates that nothing must be computed. */ static final int COMPUTE_NOTHING = 0; /** * Indicates that the maximum stack size and the maximum number of local variables must be * computed, from scratch. */ static final int COMPUTE_MAX_STACK_AND_LOCAL = 1; /** * Indicates that the maximum stack size and the maximum number of local variables must be * computed, from the existing stack map frames. This can be done more efficiently than with the * control flow graph algorithm used for {@link #COMPUTE_MAX_STACK_AND_LOCAL}, by using a linear * scan of the bytecode instructions. */ static final int COMPUTE_MAX_STACK_AND_LOCAL_FROM_FRAMES = 2; /** * Indicates that the stack map frames of type F_INSERT must be computed. The other frames are not * computed. They should all be of type F_NEW and should be sufficient to compute the content of * the F_INSERT frames, together with the bytecode instructions between a F_NEW and a F_INSERT * frame - and without any knowledge of the type hierarchy (by definition of F_INSERT). */ static final int COMPUTE_INSERTED_FRAMES = 3; /** * Indicates that all the stack map frames must be computed. In this case the maximum stack size * and the maximum number of local variables is also computed. */ static final int COMPUTE_ALL_FRAMES = 4; /** Indicates that {@link #STACK_SIZE_DELTA} is not applicable (not constant or never used). */ private static final int NA = 0; /** * The stack size variation corresponding to each JVM opcode. The stack size variation for opcode * 'o' is given by the array element at index 'o'. * * @see JVMS 6 */ private static final int[] STACK_SIZE_DELTA = { 0, // nop = 0 (0x0) 1, // aconst_null = 1 (0x1) 1, // iconst_m1 = 2 (0x2) 1, // iconst_0 = 3 (0x3) 1, // iconst_1 = 4 (0x4) 1, // iconst_2 = 5 (0x5) 1, // iconst_3 = 6 (0x6) 1, // iconst_4 = 7 (0x7) 1, // iconst_5 = 8 (0x8) 2, // lconst_0 = 9 (0x9) 2, // lconst_1 = 10 (0xa) 1, // fconst_0 = 11 (0xb) 1, // fconst_1 = 12 (0xc) 1, // fconst_2 = 13 (0xd) 2, // dconst_0 = 14 (0xe) 2, // dconst_1 = 15 (0xf) 1, // bipush = 16 (0x10) 1, // sipush = 17 (0x11) 1, // ldc = 18 (0x12) NA, // ldc_w = 19 (0x13) NA, // ldc2_w = 20 (0x14) 1, // iload = 21 (0x15) 2, // lload = 22 (0x16) 1, // fload = 23 (0x17) 2, // dload = 24 (0x18) 1, // aload = 25 (0x19) NA, // iload_0 = 26 (0x1a) NA, // iload_1 = 27 (0x1b) NA, // iload_2 = 28 (0x1c) NA, // iload_3 = 29 (0x1d) NA, // lload_0 = 30 (0x1e) NA, // lload_1 = 31 (0x1f) NA, // lload_2 = 32 (0x20) NA, // lload_3 = 33 (0x21) NA, // fload_0 = 34 (0x22) NA, // fload_1 = 35 (0x23) NA, // fload_2 = 36 (0x24) NA, // fload_3 = 37 (0x25) NA, // dload_0 = 38 (0x26) NA, // dload_1 = 39 (0x27) NA, // dload_2 = 40 (0x28) NA, // dload_3 = 41 (0x29) NA, // aload_0 = 42 (0x2a) NA, // aload_1 = 43 (0x2b) NA, // aload_2 = 44 (0x2c) NA, // aload_3 = 45 (0x2d) -1, // iaload = 46 (0x2e) 0, // laload = 47 (0x2f) -1, // faload = 48 (0x30) 0, // daload = 49 (0x31) -1, // aaload = 50 (0x32) -1, // baload = 51 (0x33) -1, // caload = 52 (0x34) -1, // saload = 53 (0x35) -1, // istore = 54 (0x36) -2, // lstore = 55 (0x37) -1, // fstore = 56 (0x38) -2, // dstore = 57 (0x39) -1, // astore = 58 (0x3a) NA, // istore_0 = 59 (0x3b) NA, // istore_1 = 60 (0x3c) NA, // istore_2 = 61 (0x3d) NA, // istore_3 = 62 (0x3e) NA, // lstore_0 = 63 (0x3f) NA, // lstore_1 = 64 (0x40) NA, // lstore_2 = 65 (0x41) NA, // lstore_3 = 66 (0x42) NA, // fstore_0 = 67 (0x43) NA, // fstore_1 = 68 (0x44) NA, // fstore_2 = 69 (0x45) NA, // fstore_3 = 70 (0x46) NA, // dstore_0 = 71 (0x47) NA, // dstore_1 = 72 (0x48) NA, // dstore_2 = 73 (0x49) NA, // dstore_3 = 74 (0x4a) NA, // astore_0 = 75 (0x4b) NA, // astore_1 = 76 (0x4c) NA, // astore_2 = 77 (0x4d) NA, // astore_3 = 78 (0x4e) -3, // iastore = 79 (0x4f) -4, // lastore = 80 (0x50) -3, // fastore = 81 (0x51) -4, // dastore = 82 (0x52) -3, // aastore = 83 (0x53) -3, // bastore = 84 (0x54) -3, // castore = 85 (0x55) -3, // sastore = 86 (0x56) -1, // pop = 87 (0x57) -2, // pop2 = 88 (0x58) 1, // dup = 89 (0x59) 1, // dup_x1 = 90 (0x5a) 1, // dup_x2 = 91 (0x5b) 2, // dup2 = 92 (0x5c) 2, // dup2_x1 = 93 (0x5d) 2, // dup2_x2 = 94 (0x5e) 0, // swap = 95 (0x5f) -1, // iadd = 96 (0x60) -2, // ladd = 97 (0x61) -1, // fadd = 98 (0x62) -2, // dadd = 99 (0x63) -1, // isub = 100 (0x64) -2, // lsub = 101 (0x65) -1, // fsub = 102 (0x66) -2, // dsub = 103 (0x67) -1, // imul = 104 (0x68) -2, // lmul = 105 (0x69) -1, // fmul = 106 (0x6a) -2, // dmul = 107 (0x6b) -1, // idiv = 108 (0x6c) -2, // ldiv = 109 (0x6d) -1, // fdiv = 110 (0x6e) -2, // ddiv = 111 (0x6f) -1, // irem = 112 (0x70) -2, // lrem = 113 (0x71) -1, // frem = 114 (0x72) -2, // drem = 115 (0x73) 0, // ineg = 116 (0x74) 0, // lneg = 117 (0x75) 0, // fneg = 118 (0x76) 0, // dneg = 119 (0x77) -1, // ishl = 120 (0x78) -1, // lshl = 121 (0x79) -1, // ishr = 122 (0x7a) -1, // lshr = 123 (0x7b) -1, // iushr = 124 (0x7c) -1, // lushr = 125 (0x7d) -1, // iand = 126 (0x7e) -2, // land = 127 (0x7f) -1, // ior = 128 (0x80) -2, // lor = 129 (0x81) -1, // ixor = 130 (0x82) -2, // lxor = 131 (0x83) 0, // iinc = 132 (0x84) 1, // i2l = 133 (0x85) 0, // i2f = 134 (0x86) 1, // i2d = 135 (0x87) -1, // l2i = 136 (0x88) -1, // l2f = 137 (0x89) 0, // l2d = 138 (0x8a) 0, // f2i = 139 (0x8b) 1, // f2l = 140 (0x8c) 1, // f2d = 141 (0x8d) -1, // d2i = 142 (0x8e) 0, // d2l = 143 (0x8f) -1, // d2f = 144 (0x90) 0, // i2b = 145 (0x91) 0, // i2c = 146 (0x92) 0, // i2s = 147 (0x93) -3, // lcmp = 148 (0x94) -1, // fcmpl = 149 (0x95) -1, // fcmpg = 150 (0x96) -3, // dcmpl = 151 (0x97) -3, // dcmpg = 152 (0x98) -1, // ifeq = 153 (0x99) -1, // ifne = 154 (0x9a) -1, // iflt = 155 (0x9b) -1, // ifge = 156 (0x9c) -1, // ifgt = 157 (0x9d) -1, // ifle = 158 (0x9e) -2, // if_icmpeq = 159 (0x9f) -2, // if_icmpne = 160 (0xa0) -2, // if_icmplt = 161 (0xa1) -2, // if_icmpge = 162 (0xa2) -2, // if_icmpgt = 163 (0xa3) -2, // if_icmple = 164 (0xa4) -2, // if_acmpeq = 165 (0xa5) -2, // if_acmpne = 166 (0xa6) 0, // goto = 167 (0xa7) 1, // jsr = 168 (0xa8) 0, // ret = 169 (0xa9) -1, // tableswitch = 170 (0xaa) -1, // lookupswitch = 171 (0xab) -1, // ireturn = 172 (0xac) -2, // lreturn = 173 (0xad) -1, // freturn = 174 (0xae) -2, // dreturn = 175 (0xaf) -1, // areturn = 176 (0xb0) 0, // return = 177 (0xb1) NA, // getstatic = 178 (0xb2) NA, // putstatic = 179 (0xb3) NA, // getfield = 180 (0xb4) NA, // putfield = 181 (0xb5) NA, // invokevirtual = 182 (0xb6) NA, // invokespecial = 183 (0xb7) NA, // invokestatic = 184 (0xb8) NA, // invokeinterface = 185 (0xb9) NA, // invokedynamic = 186 (0xba) 1, // new = 187 (0xbb) 0, // newarray = 188 (0xbc) 0, // anewarray = 189 (0xbd) 0, // arraylength = 190 (0xbe) NA, // athrow = 191 (0xbf) 0, // checkcast = 192 (0xc0) 0, // instanceof = 193 (0xc1) -1, // monitorenter = 194 (0xc2) -1, // monitorexit = 195 (0xc3) NA, // wide = 196 (0xc4) NA, // multianewarray = 197 (0xc5) -1, // ifnull = 198 (0xc6) -1, // ifnonnull = 199 (0xc7) NA, // goto_w = 200 (0xc8) NA // jsr_w = 201 (0xc9) }; /** Where the constants used in this MethodWriter must be stored. */ private final SymbolTable symbolTable; // Note: fields are ordered as in the method_info structure, and those related to attributes are // ordered as in Section 4.7 of the JVMS. /** * The access_flags field of the method_info JVMS structure. This field can contain ASM specific * access flags, such as {@link Opcodes#ACC_DEPRECATED}, which are removed when generating the * ClassFile structure. */ private final int accessFlags; /** The name_index field of the method_info JVMS structure. */ private final int nameIndex; /** The name of this method. */ private final String name; /** The descriptor_index field of the method_info JVMS structure. */ private final int descriptorIndex; /** The descriptor of this method. */ private final String descriptor; // Code attribute fields and sub attributes: /** The max_stack field of the Code attribute. */ private int maxStack; /** The max_locals field of the Code attribute. */ private int maxLocals; /** The 'code' field of the Code attribute. */ private final ByteVector code = new ByteVector(); /** * The first element in the exception handler list (used to generate the exception_table of the * Code attribute). The next ones can be accessed with the {@link Handler#nextHandler} field. May * be {@literal null}. */ private Handler firstHandler; /** * The last element in the exception handler list (used to generate the exception_table of the * Code attribute). The next ones can be accessed with the {@link Handler#nextHandler} field. May * be {@literal null}. */ private Handler lastHandler; /** The line_number_table_length field of the LineNumberTable code attribute. */ private int lineNumberTableLength; /** The line_number_table array of the LineNumberTable code attribute, or {@literal null}. */ private ByteVector lineNumberTable; /** The local_variable_table_length field of the LocalVariableTable code attribute. */ private int localVariableTableLength; /** * The local_variable_table array of the LocalVariableTable code attribute, or {@literal null}. */ private ByteVector localVariableTable; /** The local_variable_type_table_length field of the LocalVariableTypeTable code attribute. */ private int localVariableTypeTableLength; /** * The local_variable_type_table array of the LocalVariableTypeTable code attribute, or {@literal * null}. */ private ByteVector localVariableTypeTable; /** The number_of_entries field of the StackMapTable code attribute. */ private int stackMapTableNumberOfEntries; /** The 'entries' array of the StackMapTable code attribute. */ private ByteVector stackMapTableEntries; /** * The last runtime visible type annotation of the Code attribute. The previous ones can be * accessed with the {@link AnnotationWriter#previousAnnotation} field. May be {@literal null}. */ private AnnotationWriter lastCodeRuntimeVisibleTypeAnnotation; /** * The last runtime invisible type annotation of the Code attribute. The previous ones can be * accessed with the {@link AnnotationWriter#previousAnnotation} field. May be {@literal null}. */ private AnnotationWriter lastCodeRuntimeInvisibleTypeAnnotation; /** * The first non standard attribute of the Code attribute. The next ones can be accessed with the * {@link Attribute#nextAttribute} field. May be {@literal null}. * *

WARNING: this list stores the attributes in the reverse order of their visit. * firstAttribute is actually the last attribute visited in {@link #visitAttribute}. The {@link * #putMethodInfo} method writes the attributes in the order defined by this list, i.e. in the * reverse order specified by the user. */ private Attribute firstAttribute; // ----------------------------------------------------------------------------------------------- // Fields used to compute the maximum stack size and number of locals, and the stack map frames // ----------------------------------------------------------------------------------------------- /** * Indicates what must be computed. Must be one of {@link #COMPUTE_ALL_FRAMES}, {@link * #COMPUTE_INSERTED_FRAMES}, {@link COMPUTE_MAX_STACK_AND_LOCAL_FROM_FRAMES}, {@link * #COMPUTE_MAX_STACK_AND_LOCAL} or {@link #COMPUTE_NOTHING}. */ private final int compute; /** * The first basic block of the method. The next ones (in bytecode offset order) can be accessed * with the {@link Label#nextBasicBlock} field. */ private Label firstBasicBlock; /** * The last basic block of the method (in bytecode offset order). This field is updated each time * a basic block is encountered, and is used to append it at the end of the basic block list. */ private Label lastBasicBlock; /** * The current basic block, i.e. the basic block of the last visited instruction. When {@link * #compute} is equal to {@link #COMPUTE_MAX_STACK_AND_LOCAL} or {@link #COMPUTE_ALL_FRAMES}, this * field is {@literal null} for unreachable code. When {@link #compute} is equal to {@link * #COMPUTE_MAX_STACK_AND_LOCAL_FROM_FRAMES} or {@link #COMPUTE_INSERTED_FRAMES}, this field stays * unchanged throughout the whole method (i.e. the whole code is seen as a single basic block; * indeed, the existing frames are sufficient by hypothesis to compute any intermediate frame - * and the maximum stack size as well - without using any control flow graph). */ private Label currentBasicBlock; /** * The relative stack size after the last visited instruction. This size is relative to the * beginning of {@link #currentBasicBlock}, i.e. the true stack size after the last visited * instruction is equal to the {@link Label#inputStackSize} of the current basic block plus {@link * #relativeStackSize}. When {@link #compute} is equal to {@link * #COMPUTE_MAX_STACK_AND_LOCAL_FROM_FRAMES}, {@link #currentBasicBlock} is always the start of * the method, so this relative size is also equal to the absolute stack size after the last * visited instruction. */ private int relativeStackSize; /** * The maximum relative stack size after the last visited instruction. This size is relative to * the beginning of {@link #currentBasicBlock}, i.e. the true maximum stack size after the last * visited instruction is equal to the {@link Label#inputStackSize} of the current basic block * plus {@link #maxRelativeStackSize}.When {@link #compute} is equal to {@link * #COMPUTE_MAX_STACK_AND_LOCAL_FROM_FRAMES}, {@link #currentBasicBlock} is always the start of * the method, so this relative size is also equal to the absolute maximum stack size after the * last visited instruction. */ private int maxRelativeStackSize; /** The number of local variables in the last visited stack map frame. */ private int currentLocals; /** The bytecode offset of the last frame that was written in {@link #stackMapTableEntries}. */ private int previousFrameOffset; /** * The last frame that was written in {@link #stackMapTableEntries}. This field has the same * format as {@link #currentFrame}. */ private int[] previousFrame; /** * The current stack map frame. The first element contains the bytecode offset of the instruction * to which the frame corresponds, the second element is the number of locals and the third one is * the number of stack elements. The local variables start at index 3 and are followed by the * operand stack elements. In summary frame[0] = offset, frame[1] = numLocal, frame[2] = numStack. * Local variables and operand stack entries contain abstract types, as defined in {@link Frame}, * but restricted to {@link Frame#CONSTANT_KIND}, {@link Frame#REFERENCE_KIND}, {@link * Frame#UNINITIALIZED_KIND} or {@link Frame#FORWARD_UNINITIALIZED_KIND} abstract types. Long and * double types use only one array entry. */ private int[] currentFrame; /** Whether this method contains subroutines. */ private boolean hasSubroutines; // ----------------------------------------------------------------------------------------------- // Other miscellaneous status fields // ----------------------------------------------------------------------------------------------- /** Whether the bytecode of this method contains ASM specific instructions. */ private boolean hasAsmInstructions; /** * The start offset of the last visited instruction. Used to set the offset field of type * annotations of type 'offset_target' (see JVMS * 4.7.20.1). */ private int lastBytecodeOffset; /** * The offset in bytes in {@link SymbolTable#getSource} from which the method_info for this method * (excluding its first 6 bytes) must be copied, or 0. */ private int sourceOffset; /** * The length in bytes in {@link SymbolTable#getSource} which must be copied to get the * method_info for this method (excluding its first 6 bytes for access_flags, name_index and * descriptor_index). */ private int sourceLength; // ----------------------------------------------------------------------------------------------- // Constructor and accessors // ----------------------------------------------------------------------------------------------- /** * Constructs a new {@link MethodWriter}. * * @param symbolTable where the constants used in this AnnotationWriter must be stored. * @param access the method's access flags (see {@link Opcodes}). * @param name the method's name. * @param descriptor the method's descriptor (see {@link Type}). * @param signature the method's signature. May be {@literal null}. * @param exceptions the internal names of the method's exceptions. May be {@literal null}. * @param compute indicates what must be computed (see #compute). */ MethodWriter( final SymbolTable symbolTable, final int access, final String name, final String descriptor, final String signature, final String[] exceptions, final int compute) { super(/* latest api = */ Opcodes.ASM9); this.symbolTable = symbolTable; this.accessFlags = "".equals(name) ? access | Constants.ACC_CONSTRUCTOR : access; this.nameIndex = symbolTable.addConstantUtf8(name); this.name = name; this.descriptorIndex = symbolTable.addConstantUtf8(descriptor); this.descriptor = descriptor; this.signatureIndex = signature == null ? 0 : symbolTable.addConstantUtf8(signature); if (exceptions != null && exceptions.length > 0) { numberOfExceptions = exceptions.length; this.exceptionIndexTable = new int[numberOfExceptions]; for (int i = 0; i < numberOfExceptions; ++i) { this.exceptionIndexTable[i] = symbolTable.addConstantClass(exceptions[i]).index; } } else { numberOfExceptions = 0; this.exceptionIndexTable = null; } this.compute = compute; if (compute != COMPUTE_NOTHING) { // Update maxLocals and currentLocals. int argumentsSize = Type.getArgumentsAndReturnSizes(descriptor) >> 2; if ((access & Opcodes.ACC_STATIC) != 0) { --argumentsSize; } maxLocals = argumentsSize; currentLocals = argumentsSize; // Create and visit the label for the first basic block. firstBasicBlock = new Label(); visitLabel(firstBasicBlock); } } boolean hasFrames() { return stackMapTableNumberOfEntries > 0; } boolean hasAsmInstructions() { return hasAsmInstructions; } // ----------------------------------------------------------------------------------------------- // Implementation of the MethodVisitor abstract class // ----------------------------------------------------------------------------------------------- @Override public void visitParameter(final String name, final int access) { if (parameters == null) { parameters = new ByteVector(); } ++parametersCount; parameters.putShort((name == null) ? 0 : symbolTable.addConstantUtf8(name)).putShort(access); } @Override public AnnotationVisitor visitAnnotationDefault() { defaultValue = new ByteVector(); return new AnnotationWriter(symbolTable, /* useNamedValues= */ false, defaultValue, null); } @Override public AnnotationVisitor visitAnnotation(final String descriptor, final boolean visible) { if (visible) { return lastRuntimeVisibleAnnotation = AnnotationWriter.create(symbolTable, descriptor, lastRuntimeVisibleAnnotation); } else { return lastRuntimeInvisibleAnnotation = AnnotationWriter.create(symbolTable, descriptor, lastRuntimeInvisibleAnnotation); } } @Override public AnnotationVisitor visitTypeAnnotation( final int typeRef, final TypePath typePath, final String descriptor, final boolean visible) { if (visible) { return lastRuntimeVisibleTypeAnnotation = AnnotationWriter.create( symbolTable, typeRef, typePath, descriptor, lastRuntimeVisibleTypeAnnotation); } else { return lastRuntimeInvisibleTypeAnnotation = AnnotationWriter.create( symbolTable, typeRef, typePath, descriptor, lastRuntimeInvisibleTypeAnnotation); } } @Override public void visitAnnotableParameterCount(final int parameterCount, final boolean visible) { if (visible) { visibleAnnotableParameterCount = parameterCount; } else { invisibleAnnotableParameterCount = parameterCount; } } @Override public AnnotationVisitor visitParameterAnnotation( final int parameter, final String annotationDescriptor, final boolean visible) { if (visible) { if (lastRuntimeVisibleParameterAnnotations == null) { lastRuntimeVisibleParameterAnnotations = new AnnotationWriter[Type.getArgumentCount(descriptor)]; } return lastRuntimeVisibleParameterAnnotations[parameter] = AnnotationWriter.create( symbolTable, annotationDescriptor, lastRuntimeVisibleParameterAnnotations[parameter]); } else { if (lastRuntimeInvisibleParameterAnnotations == null) { lastRuntimeInvisibleParameterAnnotations = new AnnotationWriter[Type.getArgumentCount(descriptor)]; } return lastRuntimeInvisibleParameterAnnotations[parameter] = AnnotationWriter.create( symbolTable, annotationDescriptor, lastRuntimeInvisibleParameterAnnotations[parameter]); } } @Override public void visitAttribute(final Attribute attribute) { // Store the attributes in the reverse order of their visit by this method. if (attribute.isCodeAttribute()) { attribute.nextAttribute = firstCodeAttribute; firstCodeAttribute = attribute; } else { attribute.nextAttribute = firstAttribute; firstAttribute = attribute; } } @Override public void visitCode() { // Nothing to do. } @Override public void visitFrame( final int type, final int numLocal, final Object[] local, final int numStack, final Object[] stack) { if (compute == COMPUTE_ALL_FRAMES) { return; } if (compute == COMPUTE_INSERTED_FRAMES) { if (currentBasicBlock.frame == null) { // This should happen only once, for the implicit first frame (which is explicitly visited // in ClassReader if the EXPAND_ASM_INSNS option is used - and COMPUTE_INSERTED_FRAMES // can't be set if EXPAND_ASM_INSNS is not used). currentBasicBlock.frame = new CurrentFrame(currentBasicBlock); currentBasicBlock.frame.setInputFrameFromDescriptor( symbolTable, accessFlags, descriptor, numLocal); currentBasicBlock.frame.accept(this); } else { if (type == Opcodes.F_NEW) { currentBasicBlock.frame.setInputFrameFromApiFormat( symbolTable, numLocal, local, numStack, stack); } // If type is not F_NEW then it is F_INSERT by hypothesis, and currentBlock.frame contains // the stack map frame at the current instruction, computed from the last F_NEW frame and // the bytecode instructions in between (via calls to CurrentFrame#execute). currentBasicBlock.frame.accept(this); } } else if (type == Opcodes.F_NEW) { if (previousFrame == null) { int argumentsSize = Type.getArgumentsAndReturnSizes(descriptor) >> 2; Frame implicitFirstFrame = new Frame(new Label()); implicitFirstFrame.setInputFrameFromDescriptor( symbolTable, accessFlags, descriptor, argumentsSize); implicitFirstFrame.accept(this); } currentLocals = numLocal; int frameIndex = visitFrameStart(code.length, numLocal, numStack); for (int i = 0; i < numLocal; ++i) { currentFrame[frameIndex++] = Frame.getAbstractTypeFromApiFormat(symbolTable, local[i]); } for (int i = 0; i < numStack; ++i) { currentFrame[frameIndex++] = Frame.getAbstractTypeFromApiFormat(symbolTable, stack[i]); } visitFrameEnd(); } else { if (symbolTable.getMajorVersion() < Opcodes.V1_6) { throw new IllegalArgumentException("Class versions V1_5 or less must use F_NEW frames."); } int offsetDelta; if (stackMapTableEntries == null) { stackMapTableEntries = new ByteVector(); offsetDelta = code.length; } else { offsetDelta = code.length - previousFrameOffset - 1; if (offsetDelta < 0) { if (type == Opcodes.F_SAME) { return; } else { throw new IllegalStateException(); } } } switch (type) { case Opcodes.F_FULL: currentLocals = numLocal; stackMapTableEntries.putByte(Frame.FULL_FRAME).putShort(offsetDelta).putShort(numLocal); for (int i = 0; i < numLocal; ++i) { putFrameType(local[i]); } stackMapTableEntries.putShort(numStack); for (int i = 0; i < numStack; ++i) { putFrameType(stack[i]); } break; case Opcodes.F_APPEND: currentLocals += numLocal; stackMapTableEntries.putByte(Frame.SAME_FRAME_EXTENDED + numLocal).putShort(offsetDelta); for (int i = 0; i < numLocal; ++i) { putFrameType(local[i]); } break; case Opcodes.F_CHOP: currentLocals -= numLocal; stackMapTableEntries.putByte(Frame.SAME_FRAME_EXTENDED - numLocal).putShort(offsetDelta); break; case Opcodes.F_SAME: if (offsetDelta < 64) { stackMapTableEntries.putByte(offsetDelta); } else { stackMapTableEntries.putByte(Frame.SAME_FRAME_EXTENDED).putShort(offsetDelta); } break; case Opcodes.F_SAME1: if (offsetDelta < 64) { stackMapTableEntries.putByte(Frame.SAME_LOCALS_1_STACK_ITEM_FRAME + offsetDelta); } else { stackMapTableEntries .putByte(Frame.SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED) .putShort(offsetDelta); } putFrameType(stack[0]); break; default: throw new IllegalArgumentException(); } previousFrameOffset = code.length; ++stackMapTableNumberOfEntries; } if (compute == COMPUTE_MAX_STACK_AND_LOCAL_FROM_FRAMES) { relativeStackSize = numStack; for (int i = 0; i < numStack; ++i) { if (stack[i] == Opcodes.LONG || stack[i] == Opcodes.DOUBLE) { relativeStackSize++; } } if (relativeStackSize > maxRelativeStackSize) { maxRelativeStackSize = relativeStackSize; } } maxStack = Math.max(maxStack, numStack); maxLocals = Math.max(maxLocals, currentLocals); } @Override public void visitInsn(final int opcode) { lastBytecodeOffset = code.length; // Add the instruction to the bytecode of the method. code.putByte(opcode); // If needed, update the maximum stack size and number of locals, and stack map frames. if (currentBasicBlock != null) { if (compute == COMPUTE_ALL_FRAMES || compute == COMPUTE_INSERTED_FRAMES) { currentBasicBlock.frame.execute(opcode, 0, null, null); } else { int size = relativeStackSize + STACK_SIZE_DELTA[opcode]; if (size > maxRelativeStackSize) { maxRelativeStackSize = size; } relativeStackSize = size; } if ((opcode >= Opcodes.IRETURN && opcode <= Opcodes.RETURN) || opcode == Opcodes.ATHROW) { endCurrentBasicBlockWithNoSuccessor(); } } } @Override public void visitIntInsn(final int opcode, final int operand) { lastBytecodeOffset = code.length; // Add the instruction to the bytecode of the method. if (opcode == Opcodes.SIPUSH) { code.put12(opcode, operand); } else { // BIPUSH or NEWARRAY code.put11(opcode, operand); } // If needed, update the maximum stack size and number of locals, and stack map frames. if (currentBasicBlock != null) { if (compute == COMPUTE_ALL_FRAMES || compute == COMPUTE_INSERTED_FRAMES) { currentBasicBlock.frame.execute(opcode, operand, null, null); } else if (opcode != Opcodes.NEWARRAY) { // The stack size delta is 1 for BIPUSH or SIPUSH, and 0 for NEWARRAY. int size = relativeStackSize + 1; if (size > maxRelativeStackSize) { maxRelativeStackSize = size; } relativeStackSize = size; } } } @Override public void visitVarInsn(final int opcode, final int varIndex) { lastBytecodeOffset = code.length; // Add the instruction to the bytecode of the method. if (varIndex < 4 && opcode != Opcodes.RET) { int optimizedOpcode; if (opcode < Opcodes.ISTORE) { optimizedOpcode = Constants.ILOAD_0 + ((opcode - Opcodes.ILOAD) << 2) + varIndex; } else { optimizedOpcode = Constants.ISTORE_0 + ((opcode - Opcodes.ISTORE) << 2) + varIndex; } code.putByte(optimizedOpcode); } else if (varIndex >= 256) { code.putByte(Constants.WIDE).put12(opcode, varIndex); } else { code.put11(opcode, varIndex); } // If needed, update the maximum stack size and number of locals, and stack map frames. if (currentBasicBlock != null) { if (compute == COMPUTE_ALL_FRAMES || compute == COMPUTE_INSERTED_FRAMES) { currentBasicBlock.frame.execute(opcode, varIndex, null, null); } else { if (opcode == Opcodes.RET) { // No stack size delta. currentBasicBlock.flags |= Label.FLAG_SUBROUTINE_END; currentBasicBlock.outputStackSize = (short) relativeStackSize; endCurrentBasicBlockWithNoSuccessor(); } else { // xLOAD or xSTORE int size = relativeStackSize + STACK_SIZE_DELTA[opcode]; if (size > maxRelativeStackSize) { maxRelativeStackSize = size; } relativeStackSize = size; } } } if (compute != COMPUTE_NOTHING) { int currentMaxLocals; if (opcode == Opcodes.LLOAD || opcode == Opcodes.DLOAD || opcode == Opcodes.LSTORE || opcode == Opcodes.DSTORE) { currentMaxLocals = varIndex + 2; } else { currentMaxLocals = varIndex + 1; } if (currentMaxLocals > maxLocals) { maxLocals = currentMaxLocals; } } if (opcode >= Opcodes.ISTORE && compute == COMPUTE_ALL_FRAMES && firstHandler != null) { // If there are exception handler blocks, each instruction within a handler range is, in // theory, a basic block (since execution can jump from this instruction to the exception // handler). As a consequence, the local variable types at the beginning of the handler // block should be the merge of the local variable types at all the instructions within the // handler range. However, instead of creating a basic block for each instruction, we can // get the same result in a more efficient way. Namely, by starting a new basic block after // each xSTORE instruction, which is what we do here. visitLabel(new Label()); } } @Override public void visitTypeInsn(final int opcode, final String type) { lastBytecodeOffset = code.length; // Add the instruction to the bytecode of the method. Symbol typeSymbol = symbolTable.addConstantClass(type); code.put12(opcode, typeSymbol.index); // If needed, update the maximum stack size and number of locals, and stack map frames. if (currentBasicBlock != null) { if (compute == COMPUTE_ALL_FRAMES || compute == COMPUTE_INSERTED_FRAMES) { currentBasicBlock.frame.execute(opcode, lastBytecodeOffset, typeSymbol, symbolTable); } else if (opcode == Opcodes.NEW) { // The stack size delta is 1 for NEW, and 0 for ANEWARRAY, CHECKCAST, or INSTANCEOF. int size = relativeStackSize + 1; if (size > maxRelativeStackSize) { maxRelativeStackSize = size; } relativeStackSize = size; } } } @Override public void visitFieldInsn( final int opcode, final String owner, final String name, final String descriptor) { lastBytecodeOffset = code.length; // Add the instruction to the bytecode of the method. Symbol fieldrefSymbol = symbolTable.addConstantFieldref(owner, name, descriptor); code.put12(opcode, fieldrefSymbol.index); // If needed, update the maximum stack size and number of locals, and stack map frames. if (currentBasicBlock != null) { if (compute == COMPUTE_ALL_FRAMES || compute == COMPUTE_INSERTED_FRAMES) { currentBasicBlock.frame.execute(opcode, 0, fieldrefSymbol, symbolTable); } else { int size; char firstDescChar = descriptor.charAt(0); switch (opcode) { case Opcodes.GETSTATIC: size = relativeStackSize + (firstDescChar == 'D' || firstDescChar == 'J' ? 2 : 1); break; case Opcodes.PUTSTATIC: size = relativeStackSize + (firstDescChar == 'D' || firstDescChar == 'J' ? -2 : -1); break; case Opcodes.GETFIELD: size = relativeStackSize + (firstDescChar == 'D' || firstDescChar == 'J' ? 1 : 0); break; case Opcodes.PUTFIELD: default: size = relativeStackSize + (firstDescChar == 'D' || firstDescChar == 'J' ? -3 : -2); break; } if (size > maxRelativeStackSize) { maxRelativeStackSize = size; } relativeStackSize = size; } } } @Override public void visitMethodInsn( final int opcode, final String owner, final String name, final String descriptor, final boolean isInterface) { lastBytecodeOffset = code.length; // Add the instruction to the bytecode of the method. Symbol methodrefSymbol = symbolTable.addConstantMethodref(owner, name, descriptor, isInterface); if (opcode == Opcodes.INVOKEINTERFACE) { code.put12(Opcodes.INVOKEINTERFACE, methodrefSymbol.index) .put11(methodrefSymbol.getArgumentsAndReturnSizes() >> 2, 0); } else { code.put12(opcode, methodrefSymbol.index); } // If needed, update the maximum stack size and number of locals, and stack map frames. if (currentBasicBlock != null) { if (compute == COMPUTE_ALL_FRAMES || compute == COMPUTE_INSERTED_FRAMES) { currentBasicBlock.frame.execute(opcode, 0, methodrefSymbol, symbolTable); } else { int argumentsAndReturnSize = methodrefSymbol.getArgumentsAndReturnSizes(); int stackSizeDelta = (argumentsAndReturnSize & 3) - (argumentsAndReturnSize >> 2); int size; if (opcode == Opcodes.INVOKESTATIC) { size = relativeStackSize + stackSizeDelta + 1; } else { size = relativeStackSize + stackSizeDelta; } if (size > maxRelativeStackSize) { maxRelativeStackSize = size; } relativeStackSize = size; } } } @Override public void visitInvokeDynamicInsn( final String name, final String descriptor, final Handle bootstrapMethodHandle, final Object... bootstrapMethodArguments) { lastBytecodeOffset = code.length; // Add the instruction to the bytecode of the method. Symbol invokeDynamicSymbol = symbolTable.addConstantInvokeDynamic( name, descriptor, bootstrapMethodHandle, bootstrapMethodArguments); code.put12(Opcodes.INVOKEDYNAMIC, invokeDynamicSymbol.index); code.putShort(0); // If needed, update the maximum stack size and number of locals, and stack map frames. if (currentBasicBlock != null) { if (compute == COMPUTE_ALL_FRAMES || compute == COMPUTE_INSERTED_FRAMES) { currentBasicBlock.frame.execute(Opcodes.INVOKEDYNAMIC, 0, invokeDynamicSymbol, symbolTable); } else { int argumentsAndReturnSize = invokeDynamicSymbol.getArgumentsAndReturnSizes(); int stackSizeDelta = (argumentsAndReturnSize & 3) - (argumentsAndReturnSize >> 2) + 1; int size = relativeStackSize + stackSizeDelta; if (size > maxRelativeStackSize) { maxRelativeStackSize = size; } relativeStackSize = size; } } } @Override public void visitJumpInsn(final int opcode, final Label label) { lastBytecodeOffset = code.length; // Add the instruction to the bytecode of the method. // Compute the 'base' opcode, i.e. GOTO or JSR if opcode is GOTO_W or JSR_W, otherwise opcode. int baseOpcode = opcode >= Constants.GOTO_W ? opcode - Constants.WIDE_JUMP_OPCODE_DELTA : opcode; boolean nextInsnIsJumpTarget = false; if ((label.flags & Label.FLAG_RESOLVED) != 0 && label.bytecodeOffset - code.length < Short.MIN_VALUE) { // Case of a backward jump with an offset < -32768. In this case we automatically replace GOTO // with GOTO_W, JSR with JSR_W and IFxxx with IFNOTxxx GOTO_W L:..., where // IFNOTxxx is the "opposite" opcode of IFxxx (e.g. IFNE for IFEQ) and where designates // the instruction just after the GOTO_W. if (baseOpcode == Opcodes.GOTO) { code.putByte(Constants.GOTO_W); } else if (baseOpcode == Opcodes.JSR) { code.putByte(Constants.JSR_W); } else { // Put the "opposite" opcode of baseOpcode. This can be done by flipping the least // significant bit for IFNULL and IFNONNULL, and similarly for IFEQ ... IF_ACMPEQ (with a // pre and post offset by 1). The jump offset is 8 bytes (3 for IFNOTxxx, 5 for GOTO_W). code.putByte(baseOpcode >= Opcodes.IFNULL ? baseOpcode ^ 1 : ((baseOpcode + 1) ^ 1) - 1); code.putShort(8); // Here we could put a GOTO_W in theory, but if ASM specific instructions are used in this // method or another one, and if the class has frames, we will need to insert a frame after // this GOTO_W during the additional ClassReader -> ClassWriter round trip to remove the ASM // specific instructions. To not miss this additional frame, we need to use an ASM_GOTO_W // here, which has the unfortunate effect of forcing this additional round trip (which in // some case would not have been really necessary, but we can't know this at this point). code.putByte(Constants.ASM_GOTO_W); hasAsmInstructions = true; // The instruction after the GOTO_W becomes the target of the IFNOT instruction. nextInsnIsJumpTarget = true; } label.put(code, code.length - 1, true); } else if (baseOpcode != opcode) { // Case of a GOTO_W or JSR_W specified by the user (normally ClassReader when used to remove // ASM specific instructions). In this case we keep the original instruction. code.putByte(opcode); label.put(code, code.length - 1, true); } else { // Case of a jump with an offset >= -32768, or of a jump with an unknown offset. In these // cases we store the offset in 2 bytes (which will be increased via a ClassReader -> // ClassWriter round trip if it turns out that 2 bytes are not sufficient). code.putByte(baseOpcode); label.put(code, code.length - 1, false); } // If needed, update the maximum stack size and number of locals, and stack map frames. if (currentBasicBlock != null) { Label nextBasicBlock = null; if (compute == COMPUTE_ALL_FRAMES) { currentBasicBlock.frame.execute(baseOpcode, 0, null, null); // Record the fact that 'label' is the target of a jump instruction. label.getCanonicalInstance().flags |= Label.FLAG_JUMP_TARGET; // Add 'label' as a successor of the current basic block. addSuccessorToCurrentBasicBlock(Edge.JUMP, label); if (baseOpcode != Opcodes.GOTO) { // The next instruction starts a new basic block (except for GOTO: by default the code // following a goto is unreachable - unless there is an explicit label for it - and we // should not compute stack frame types for its instructions). nextBasicBlock = new Label(); } } else if (compute == COMPUTE_INSERTED_FRAMES) { currentBasicBlock.frame.execute(baseOpcode, 0, null, null); } else if (compute == COMPUTE_MAX_STACK_AND_LOCAL_FROM_FRAMES) { // No need to update maxRelativeStackSize (the stack size delta is always negative). relativeStackSize += STACK_SIZE_DELTA[baseOpcode]; } else { if (baseOpcode == Opcodes.JSR) { // Record the fact that 'label' designates a subroutine, if not already done. if ((label.flags & Label.FLAG_SUBROUTINE_START) == 0) { label.flags |= Label.FLAG_SUBROUTINE_START; hasSubroutines = true; } currentBasicBlock.flags |= Label.FLAG_SUBROUTINE_CALLER; // Note that, by construction in this method, a block which calls a subroutine has at // least two successors in the control flow graph: the first one (added below) leads to // the instruction after the JSR, while the second one (added here) leads to the JSR // target. Note that the first successor is virtual (it does not correspond to a possible // execution path): it is only used to compute the successors of the basic blocks ending // with a ret, in {@link Label#addSubroutineRetSuccessors}. addSuccessorToCurrentBasicBlock(relativeStackSize + 1, label); // The instruction after the JSR starts a new basic block. nextBasicBlock = new Label(); } else { // No need to update maxRelativeStackSize (the stack size delta is always negative). relativeStackSize += STACK_SIZE_DELTA[baseOpcode]; addSuccessorToCurrentBasicBlock(relativeStackSize, label); } } // If the next instruction starts a new basic block, call visitLabel to add the label of this // instruction as a successor of the current block, and to start a new basic block. if (nextBasicBlock != null) { if (nextInsnIsJumpTarget) { nextBasicBlock.flags |= Label.FLAG_JUMP_TARGET; } visitLabel(nextBasicBlock); } if (baseOpcode == Opcodes.GOTO) { endCurrentBasicBlockWithNoSuccessor(); } } } @Override public void visitLabel(final Label label) { // Resolve the forward references to this label, if any. hasAsmInstructions |= label.resolve(code.data, stackMapTableEntries, code.length); // visitLabel starts a new basic block (except for debug only labels), so we need to update the // previous and current block references and list of successors. if ((label.flags & Label.FLAG_DEBUG_ONLY) != 0) { return; } if (compute == COMPUTE_ALL_FRAMES) { if (currentBasicBlock != null) { if (label.bytecodeOffset == currentBasicBlock.bytecodeOffset) { // We use {@link Label#getCanonicalInstance} to store the state of a basic block in only // one place, but this does not work for labels which have not been visited yet. // Therefore, when we detect here two labels having the same bytecode offset, we need to // - consolidate the state scattered in these two instances into the canonical instance: currentBasicBlock.flags |= (label.flags & Label.FLAG_JUMP_TARGET); // - make sure the two instances share the same Frame instance (the implementation of // {@link Label#getCanonicalInstance} relies on this property; here label.frame should be // null): label.frame = currentBasicBlock.frame; // - and make sure to NOT assign 'label' into 'currentBasicBlock' or 'lastBasicBlock', so // that they still refer to the canonical instance for this bytecode offset. return; } // End the current basic block (with one new successor). addSuccessorToCurrentBasicBlock(Edge.JUMP, label); } // Append 'label' at the end of the basic block list. if (lastBasicBlock != null) { if (label.bytecodeOffset == lastBasicBlock.bytecodeOffset) { // Same comment as above. lastBasicBlock.flags |= (label.flags & Label.FLAG_JUMP_TARGET); // Here label.frame should be null. label.frame = lastBasicBlock.frame; currentBasicBlock = lastBasicBlock; return; } lastBasicBlock.nextBasicBlock = label; } lastBasicBlock = label; // Make it the new current basic block. currentBasicBlock = label; // Here label.frame should be null. label.frame = new Frame(label); } else if (compute == COMPUTE_INSERTED_FRAMES) { if (currentBasicBlock == null) { // This case should happen only once, for the visitLabel call in the constructor. Indeed, if // compute is equal to COMPUTE_INSERTED_FRAMES, currentBasicBlock stays unchanged. currentBasicBlock = label; } else { // Update the frame owner so that a correct frame offset is computed in Frame.accept(). currentBasicBlock.frame.owner = label; } } else if (compute == COMPUTE_MAX_STACK_AND_LOCAL) { if (currentBasicBlock != null) { // End the current basic block (with one new successor). currentBasicBlock.outputStackMax = (short) maxRelativeStackSize; addSuccessorToCurrentBasicBlock(relativeStackSize, label); } // Start a new current basic block, and reset the current and maximum relative stack sizes. currentBasicBlock = label; relativeStackSize = 0; maxRelativeStackSize = 0; // Append the new basic block at the end of the basic block list. if (lastBasicBlock != null) { lastBasicBlock.nextBasicBlock = label; } lastBasicBlock = label; } else if (compute == COMPUTE_MAX_STACK_AND_LOCAL_FROM_FRAMES && currentBasicBlock == null) { // This case should happen only once, for the visitLabel call in the constructor. Indeed, if // compute is equal to COMPUTE_MAX_STACK_AND_LOCAL_FROM_FRAMES, currentBasicBlock stays // unchanged. currentBasicBlock = label; } } @Override public void visitLdcInsn(final Object value) { lastBytecodeOffset = code.length; // Add the instruction to the bytecode of the method. Symbol constantSymbol = symbolTable.addConstant(value); int constantIndex = constantSymbol.index; char firstDescriptorChar; boolean isLongOrDouble = constantSymbol.tag == Symbol.CONSTANT_LONG_TAG || constantSymbol.tag == Symbol.CONSTANT_DOUBLE_TAG || (constantSymbol.tag == Symbol.CONSTANT_DYNAMIC_TAG && ((firstDescriptorChar = constantSymbol.value.charAt(0)) == 'J' || firstDescriptorChar == 'D')); if (isLongOrDouble) { code.put12(Constants.LDC2_W, constantIndex); } else if (constantIndex >= 256) { code.put12(Constants.LDC_W, constantIndex); } else { code.put11(Opcodes.LDC, constantIndex); } // If needed, update the maximum stack size and number of locals, and stack map frames. if (currentBasicBlock != null) { if (compute == COMPUTE_ALL_FRAMES || compute == COMPUTE_INSERTED_FRAMES) { currentBasicBlock.frame.execute(Opcodes.LDC, 0, constantSymbol, symbolTable); } else { int size = relativeStackSize + (isLongOrDouble ? 2 : 1); if (size > maxRelativeStackSize) { maxRelativeStackSize = size; } relativeStackSize = size; } } } @Override public void visitIincInsn(final int varIndex, final int increment) { lastBytecodeOffset = code.length; // Add the instruction to the bytecode of the method. if ((varIndex > 255) || (increment > 127) || (increment < -128)) { code.putByte(Constants.WIDE).put12(Opcodes.IINC, varIndex).putShort(increment); } else { code.putByte(Opcodes.IINC).put11(varIndex, increment); } // If needed, update the maximum stack size and number of locals, and stack map frames. if (currentBasicBlock != null && (compute == COMPUTE_ALL_FRAMES || compute == COMPUTE_INSERTED_FRAMES)) { currentBasicBlock.frame.execute(Opcodes.IINC, varIndex, null, null); } if (compute != COMPUTE_NOTHING) { int currentMaxLocals = varIndex + 1; if (currentMaxLocals > maxLocals) { maxLocals = currentMaxLocals; } } } @Override public void visitTableSwitchInsn( final int min, final int max, final Label dflt, final Label... labels) { lastBytecodeOffset = code.length; // Add the instruction to the bytecode of the method. code.putByte(Opcodes.TABLESWITCH).putByteArray(null, 0, (4 - code.length % 4) % 4); dflt.put(code, lastBytecodeOffset, true); code.putInt(min).putInt(max); for (Label label : labels) { label.put(code, lastBytecodeOffset, true); } // If needed, update the maximum stack size and number of locals, and stack map frames. visitSwitchInsn(dflt, labels); } @Override public void visitLookupSwitchInsn(final Label dflt, final int[] keys, final Label[] labels) { lastBytecodeOffset = code.length; // Add the instruction to the bytecode of the method. code.putByte(Opcodes.LOOKUPSWITCH).putByteArray(null, 0, (4 - code.length % 4) % 4); dflt.put(code, lastBytecodeOffset, true); code.putInt(labels.length); for (int i = 0; i < labels.length; ++i) { code.putInt(keys[i]); labels[i].put(code, lastBytecodeOffset, true); } // If needed, update the maximum stack size and number of locals, and stack map frames. visitSwitchInsn(dflt, labels); } private void visitSwitchInsn(final Label dflt, final Label[] labels) { if (currentBasicBlock != null) { if (compute == COMPUTE_ALL_FRAMES) { currentBasicBlock.frame.execute(Opcodes.LOOKUPSWITCH, 0, null, null); // Add all the labels as successors of the current basic block. addSuccessorToCurrentBasicBlock(Edge.JUMP, dflt); dflt.getCanonicalInstance().flags |= Label.FLAG_JUMP_TARGET; for (Label label : labels) { addSuccessorToCurrentBasicBlock(Edge.JUMP, label); label.getCanonicalInstance().flags |= Label.FLAG_JUMP_TARGET; } } else if (compute == COMPUTE_MAX_STACK_AND_LOCAL) { // No need to update maxRelativeStackSize (the stack size delta is always negative). --relativeStackSize; // Add all the labels as successors of the current basic block. addSuccessorToCurrentBasicBlock(relativeStackSize, dflt); for (Label label : labels) { addSuccessorToCurrentBasicBlock(relativeStackSize, label); } } // End the current basic block. endCurrentBasicBlockWithNoSuccessor(); } } @Override public void visitMultiANewArrayInsn(final String descriptor, final int numDimensions) { lastBytecodeOffset = code.length; // Add the instruction to the bytecode of the method. Symbol descSymbol = symbolTable.addConstantClass(descriptor); code.put12(Opcodes.MULTIANEWARRAY, descSymbol.index).putByte(numDimensions); // If needed, update the maximum stack size and number of locals, and stack map frames. if (currentBasicBlock != null) { if (compute == COMPUTE_ALL_FRAMES || compute == COMPUTE_INSERTED_FRAMES) { currentBasicBlock.frame.execute( Opcodes.MULTIANEWARRAY, numDimensions, descSymbol, symbolTable); } else { // No need to update maxRelativeStackSize (the stack size delta is always negative). relativeStackSize += 1 - numDimensions; } } } @Override public AnnotationVisitor visitInsnAnnotation( final int typeRef, final TypePath typePath, final String descriptor, final boolean visible) { if (visible) { return lastCodeRuntimeVisibleTypeAnnotation = AnnotationWriter.create( symbolTable, (typeRef & 0xFF0000FF) | (lastBytecodeOffset << 8), typePath, descriptor, lastCodeRuntimeVisibleTypeAnnotation); } else { return lastCodeRuntimeInvisibleTypeAnnotation = AnnotationWriter.create( symbolTable, (typeRef & 0xFF0000FF) | (lastBytecodeOffset << 8), typePath, descriptor, lastCodeRuntimeInvisibleTypeAnnotation); } } @Override public void visitTryCatchBlock( final Label start, final Label end, final Label handler, final String type) { Handler newHandler = new Handler( start, end, handler, type != null ? symbolTable.addConstantClass(type).index : 0, type); if (firstHandler == null) { firstHandler = newHandler; } else { lastHandler.nextHandler = newHandler; } lastHandler = newHandler; } @Override public AnnotationVisitor visitTryCatchAnnotation( final int typeRef, final TypePath typePath, final String descriptor, final boolean visible) { if (visible) { return lastCodeRuntimeVisibleTypeAnnotation = AnnotationWriter.create( symbolTable, typeRef, typePath, descriptor, lastCodeRuntimeVisibleTypeAnnotation); } else { return lastCodeRuntimeInvisibleTypeAnnotation = AnnotationWriter.create( symbolTable, typeRef, typePath, descriptor, lastCodeRuntimeInvisibleTypeAnnotation); } } @Override public void visitLocalVariable( final String name, final String descriptor, final String signature, final Label start, final Label end, final int index) { if (signature != null) { if (localVariableTypeTable == null) { localVariableTypeTable = new ByteVector(); } ++localVariableTypeTableLength; localVariableTypeTable .putShort(start.bytecodeOffset) .putShort(end.bytecodeOffset - start.bytecodeOffset) .putShort(symbolTable.addConstantUtf8(name)) .putShort(symbolTable.addConstantUtf8(signature)) .putShort(index); } if (localVariableTable == null) { localVariableTable = new ByteVector(); } ++localVariableTableLength; localVariableTable .putShort(start.bytecodeOffset) .putShort(end.bytecodeOffset - start.bytecodeOffset) .putShort(symbolTable.addConstantUtf8(name)) .putShort(symbolTable.addConstantUtf8(descriptor)) .putShort(index); if (compute != COMPUTE_NOTHING) { char firstDescChar = descriptor.charAt(0); int currentMaxLocals = index + (firstDescChar == 'J' || firstDescChar == 'D' ? 2 : 1); if (currentMaxLocals > maxLocals) { maxLocals = currentMaxLocals; } } } @Override public AnnotationVisitor visitLocalVariableAnnotation( final int typeRef, final TypePath typePath, final Label[] start, final Label[] end, final int[] index, final String descriptor, final boolean visible) { // Create a ByteVector to hold a 'type_annotation' JVMS structure. // See https://docs.oracle.com/javase/specs/jvms/se9/html/jvms-4.html#jvms-4.7.20. ByteVector typeAnnotation = new ByteVector(); // Write target_type, target_info, and target_path. typeAnnotation.putByte(typeRef >>> 24).putShort(start.length); for (int i = 0; i < start.length; ++i) { typeAnnotation .putShort(start[i].bytecodeOffset) .putShort(end[i].bytecodeOffset - start[i].bytecodeOffset) .putShort(index[i]); } TypePath.put(typePath, typeAnnotation); // Write type_index and reserve space for num_element_value_pairs. typeAnnotation.putShort(symbolTable.addConstantUtf8(descriptor)).putShort(0); if (visible) { return lastCodeRuntimeVisibleTypeAnnotation = new AnnotationWriter( symbolTable, /* useNamedValues= */ true, typeAnnotation, lastCodeRuntimeVisibleTypeAnnotation); } else { return lastCodeRuntimeInvisibleTypeAnnotation = new AnnotationWriter( symbolTable, /* useNamedValues= */ true, typeAnnotation, lastCodeRuntimeInvisibleTypeAnnotation); } } @Override public void visitLineNumber(final int line, final Label start) { if (lineNumberTable == null) { lineNumberTable = new ByteVector(); } ++lineNumberTableLength; lineNumberTable.putShort(start.bytecodeOffset); lineNumberTable.putShort(line); } @Override public void visitMaxs(final int maxStack, final int maxLocals) { if (compute == COMPUTE_ALL_FRAMES) { computeAllFrames(); } else if (compute == COMPUTE_MAX_STACK_AND_LOCAL) { computeMaxStackAndLocal(); } else if (compute == COMPUTE_MAX_STACK_AND_LOCAL_FROM_FRAMES) { this.maxStack = maxRelativeStackSize; } else { this.maxStack = maxStack; this.maxLocals = maxLocals; } } /** Computes all the stack map frames of the method, from scratch. */ private void computeAllFrames() { // Complete the control flow graph with exception handler blocks. Handler handler = firstHandler; while (handler != null) { String catchTypeDescriptor = handler.catchTypeDescriptor == null ? "java/lang/Throwable" : handler.catchTypeDescriptor; int catchType = Frame.getAbstractTypeFromInternalName(symbolTable, catchTypeDescriptor); // Mark handlerBlock as an exception handler. Label handlerBlock = handler.handlerPc.getCanonicalInstance(); handlerBlock.flags |= Label.FLAG_JUMP_TARGET; // Add handlerBlock as a successor of all the basic blocks in the exception handler range. Label handlerRangeBlock = handler.startPc.getCanonicalInstance(); Label handlerRangeEnd = handler.endPc.getCanonicalInstance(); while (handlerRangeBlock != handlerRangeEnd) { handlerRangeBlock.outgoingEdges = new Edge(catchType, handlerBlock, handlerRangeBlock.outgoingEdges); handlerRangeBlock = handlerRangeBlock.nextBasicBlock; } handler = handler.nextHandler; } // Create and visit the first (implicit) frame. Frame firstFrame = firstBasicBlock.frame; firstFrame.setInputFrameFromDescriptor(symbolTable, accessFlags, descriptor, this.maxLocals); firstFrame.accept(this); // Fix point algorithm: add the first basic block to a list of blocks to process (i.e. blocks // whose stack map frame has changed) and, while there are blocks to process, remove one from // the list and update the stack map frames of its successor blocks in the control flow graph // (which might change them, in which case these blocks must be processed too, and are thus // added to the list of blocks to process). Also compute the maximum stack size of the method, // as a by-product. Label listOfBlocksToProcess = firstBasicBlock; listOfBlocksToProcess.nextListElement = Label.EMPTY_LIST; int maxStackSize = 0; while (listOfBlocksToProcess != Label.EMPTY_LIST) { // Remove a basic block from the list of blocks to process. Label basicBlock = listOfBlocksToProcess; listOfBlocksToProcess = listOfBlocksToProcess.nextListElement; basicBlock.nextListElement = null; // By definition, basicBlock is reachable. basicBlock.flags |= Label.FLAG_REACHABLE; // Update the (absolute) maximum stack size. int maxBlockStackSize = basicBlock.frame.getInputStackSize() + basicBlock.outputStackMax; if (maxBlockStackSize > maxStackSize) { maxStackSize = maxBlockStackSize; } // Update the successor blocks of basicBlock in the control flow graph. Edge outgoingEdge = basicBlock.outgoingEdges; while (outgoingEdge != null) { Label successorBlock = outgoingEdge.successor.getCanonicalInstance(); boolean successorBlockChanged = basicBlock.frame.merge(symbolTable, successorBlock.frame, outgoingEdge.info); if (successorBlockChanged && successorBlock.nextListElement == null) { // If successorBlock has changed it must be processed. Thus, if it is not already in the // list of blocks to process, add it to this list. successorBlock.nextListElement = listOfBlocksToProcess; listOfBlocksToProcess = successorBlock; } outgoingEdge = outgoingEdge.nextEdge; } } // Loop over all the basic blocks and visit the stack map frames that must be stored in the // StackMapTable attribute. Also replace unreachable code with NOP* ATHROW, and remove it from // exception handler ranges. Label basicBlock = firstBasicBlock; while (basicBlock != null) { if ((basicBlock.flags & (Label.FLAG_JUMP_TARGET | Label.FLAG_REACHABLE)) == (Label.FLAG_JUMP_TARGET | Label.FLAG_REACHABLE)) { basicBlock.frame.accept(this); } if ((basicBlock.flags & Label.FLAG_REACHABLE) == 0) { // Find the start and end bytecode offsets of this unreachable block. Label nextBasicBlock = basicBlock.nextBasicBlock; int startOffset = basicBlock.bytecodeOffset; int endOffset = (nextBasicBlock == null ? code.length : nextBasicBlock.bytecodeOffset) - 1; if (endOffset >= startOffset) { // Replace its instructions with NOP ... NOP ATHROW. for (int i = startOffset; i < endOffset; ++i) { code.data[i] = Opcodes.NOP; } code.data[endOffset] = (byte) Opcodes.ATHROW; // Emit a frame for this unreachable block, with no local and a Throwable on the stack // (so that the ATHROW could consume this Throwable if it were reachable). int frameIndex = visitFrameStart(startOffset, /* numLocal = */ 0, /* numStack = */ 1); currentFrame[frameIndex] = Frame.getAbstractTypeFromInternalName(symbolTable, "java/lang/Throwable"); visitFrameEnd(); // Remove this unreachable basic block from the exception handler ranges. firstHandler = Handler.removeRange(firstHandler, basicBlock, nextBasicBlock); // The maximum stack size is now at least one, because of the Throwable declared above. maxStackSize = Math.max(maxStackSize, 1); } } basicBlock = basicBlock.nextBasicBlock; } this.maxStack = maxStackSize; } /** Computes the maximum stack size of the method. */ private void computeMaxStackAndLocal() { // Complete the control flow graph with exception handler blocks. Handler handler = firstHandler; while (handler != null) { Label handlerBlock = handler.handlerPc; Label handlerRangeBlock = handler.startPc; Label handlerRangeEnd = handler.endPc; // Add handlerBlock as a successor of all the basic blocks in the exception handler range. while (handlerRangeBlock != handlerRangeEnd) { if ((handlerRangeBlock.flags & Label.FLAG_SUBROUTINE_CALLER) == 0) { handlerRangeBlock.outgoingEdges = new Edge(Edge.EXCEPTION, handlerBlock, handlerRangeBlock.outgoingEdges); } else { // If handlerRangeBlock is a JSR block, add handlerBlock after the first two outgoing // edges to preserve the hypothesis about JSR block successors order (see // {@link #visitJumpInsn}). handlerRangeBlock.outgoingEdges.nextEdge.nextEdge = new Edge( Edge.EXCEPTION, handlerBlock, handlerRangeBlock.outgoingEdges.nextEdge.nextEdge); } handlerRangeBlock = handlerRangeBlock.nextBasicBlock; } handler = handler.nextHandler; } // Complete the control flow graph with the successor blocks of subroutines, if needed. if (hasSubroutines) { // First step: find the subroutines. This step determines, for each basic block, to which // subroutine(s) it belongs. Start with the main "subroutine": short numSubroutines = 1; firstBasicBlock.markSubroutine(numSubroutines); // Then, mark the subroutines called by the main subroutine, then the subroutines called by // those called by the main subroutine, etc. for (short currentSubroutine = 1; currentSubroutine <= numSubroutines; ++currentSubroutine) { Label basicBlock = firstBasicBlock; while (basicBlock != null) { if ((basicBlock.flags & Label.FLAG_SUBROUTINE_CALLER) != 0 && basicBlock.subroutineId == currentSubroutine) { Label jsrTarget = basicBlock.outgoingEdges.nextEdge.successor; if (jsrTarget.subroutineId == 0) { // If this subroutine has not been marked yet, find its basic blocks. jsrTarget.markSubroutine(++numSubroutines); } } basicBlock = basicBlock.nextBasicBlock; } } // Second step: find the successors in the control flow graph of each subroutine basic block // 'r' ending with a RET instruction. These successors are the virtual successors of the basic // blocks ending with JSR instructions (see {@link #visitJumpInsn)} that can reach 'r'. Label basicBlock = firstBasicBlock; while (basicBlock != null) { if ((basicBlock.flags & Label.FLAG_SUBROUTINE_CALLER) != 0) { // By construction, jsr targets are stored in the second outgoing edge of basic blocks // that ends with a jsr instruction (see {@link #FLAG_SUBROUTINE_CALLER}). Label subroutine = basicBlock.outgoingEdges.nextEdge.successor; subroutine.addSubroutineRetSuccessors(basicBlock); } basicBlock = basicBlock.nextBasicBlock; } } // Data flow algorithm: put the first basic block in a list of blocks to process (i.e. blocks // whose input stack size has changed) and, while there are blocks to process, remove one // from the list, update the input stack size of its successor blocks in the control flow // graph, and add these blocks to the list of blocks to process (if not already done). Label listOfBlocksToProcess = firstBasicBlock; listOfBlocksToProcess.nextListElement = Label.EMPTY_LIST; int maxStackSize = maxStack; while (listOfBlocksToProcess != Label.EMPTY_LIST) { // Remove a basic block from the list of blocks to process. Note that we don't reset // basicBlock.nextListElement to null on purpose, to make sure we don't reprocess already // processed basic blocks. Label basicBlock = listOfBlocksToProcess; listOfBlocksToProcess = listOfBlocksToProcess.nextListElement; // Compute the (absolute) input stack size and maximum stack size of this block. int inputStackTop = basicBlock.inputStackSize; int maxBlockStackSize = inputStackTop + basicBlock.outputStackMax; // Update the absolute maximum stack size of the method. if (maxBlockStackSize > maxStackSize) { maxStackSize = maxBlockStackSize; } // Update the input stack size of the successor blocks of basicBlock in the control flow // graph, and add these blocks to the list of blocks to process, if not already done. Edge outgoingEdge = basicBlock.outgoingEdges; if ((basicBlock.flags & Label.FLAG_SUBROUTINE_CALLER) != 0) { // Ignore the first outgoing edge of the basic blocks ending with a jsr: these are virtual // edges which lead to the instruction just after the jsr, and do not correspond to a // possible execution path (see {@link #visitJumpInsn} and // {@link Label#FLAG_SUBROUTINE_CALLER}). outgoingEdge = outgoingEdge.nextEdge; } while (outgoingEdge != null) { Label successorBlock = outgoingEdge.successor; if (successorBlock.nextListElement == null) { successorBlock.inputStackSize = (short) (outgoingEdge.info == Edge.EXCEPTION ? 1 : inputStackTop + outgoingEdge.info); successorBlock.nextListElement = listOfBlocksToProcess; listOfBlocksToProcess = successorBlock; } outgoingEdge = outgoingEdge.nextEdge; } } this.maxStack = maxStackSize; } @Override public void visitEnd() { // Nothing to do. } // ----------------------------------------------------------------------------------------------- // Utility methods: control flow analysis algorithm // ----------------------------------------------------------------------------------------------- /** * Adds a successor to {@link #currentBasicBlock} in the control flow graph. * * @param info information about the control flow edge to be added. * @param successor the successor block to be added to the current basic block. */ private void addSuccessorToCurrentBasicBlock(final int info, final Label successor) { currentBasicBlock.outgoingEdges = new Edge(info, successor, currentBasicBlock.outgoingEdges); } /** * Ends the current basic block. This method must be used in the case where the current basic * block does not have any successor. * *

WARNING: this method must be called after the currently visited instruction has been put in * {@link #code} (if frames are computed, this method inserts a new Label to start a new basic * block after the current instruction). */ private void endCurrentBasicBlockWithNoSuccessor() { if (compute == COMPUTE_ALL_FRAMES) { Label nextBasicBlock = new Label(); nextBasicBlock.frame = new Frame(nextBasicBlock); nextBasicBlock.resolve(code.data, stackMapTableEntries, code.length); lastBasicBlock.nextBasicBlock = nextBasicBlock; lastBasicBlock = nextBasicBlock; currentBasicBlock = null; } else if (compute == COMPUTE_MAX_STACK_AND_LOCAL) { currentBasicBlock.outputStackMax = (short) maxRelativeStackSize; currentBasicBlock = null; } } // ----------------------------------------------------------------------------------------------- // Utility methods: stack map frames // ----------------------------------------------------------------------------------------------- /** * Starts the visit of a new stack map frame, stored in {@link #currentFrame}. * * @param offset the bytecode offset of the instruction to which the frame corresponds. * @param numLocal the number of local variables in the frame. * @param numStack the number of stack elements in the frame. * @return the index of the next element to be written in this frame. */ int visitFrameStart(final int offset, final int numLocal, final int numStack) { int frameLength = 3 + numLocal + numStack; if (currentFrame == null || currentFrame.length < frameLength) { currentFrame = new int[frameLength]; } currentFrame[0] = offset; currentFrame[1] = numLocal; currentFrame[2] = numStack; return 3; } /** * Sets an abstract type in {@link #currentFrame}. * * @param frameIndex the index of the element to be set in {@link #currentFrame}. * @param abstractType an abstract type. */ void visitAbstractType(final int frameIndex, final int abstractType) { currentFrame[frameIndex] = abstractType; } /** * Ends the visit of {@link #currentFrame} by writing it in the StackMapTable entries and by * updating the StackMapTable number_of_entries (except if the current frame is the first one, * which is implicit in StackMapTable). Then resets {@link #currentFrame} to {@literal null}. */ void visitFrameEnd() { if (previousFrame != null) { if (stackMapTableEntries == null) { stackMapTableEntries = new ByteVector(); } putFrame(); ++stackMapTableNumberOfEntries; } previousFrame = currentFrame; currentFrame = null; } /** Compresses and writes {@link #currentFrame} in a new StackMapTable entry. */ private void putFrame() { final int numLocal = currentFrame[1]; final int numStack = currentFrame[2]; if (symbolTable.getMajorVersion() < Opcodes.V1_6) { // Generate a StackMap attribute entry, which are always uncompressed. stackMapTableEntries.putShort(currentFrame[0]).putShort(numLocal); putAbstractTypes(3, 3 + numLocal); stackMapTableEntries.putShort(numStack); putAbstractTypes(3 + numLocal, 3 + numLocal + numStack); return; } final int offsetDelta = stackMapTableNumberOfEntries == 0 ? currentFrame[0] : currentFrame[0] - previousFrame[0] - 1; final int previousNumlocal = previousFrame[1]; final int numLocalDelta = numLocal - previousNumlocal; int type = Frame.FULL_FRAME; if (numStack == 0) { switch (numLocalDelta) { case -3: case -2: case -1: type = Frame.CHOP_FRAME; break; case 0: type = offsetDelta < 64 ? Frame.SAME_FRAME : Frame.SAME_FRAME_EXTENDED; break; case 1: case 2: case 3: type = Frame.APPEND_FRAME; break; default: // Keep the FULL_FRAME type. break; } } else if (numLocalDelta == 0 && numStack == 1) { type = offsetDelta < 63 ? Frame.SAME_LOCALS_1_STACK_ITEM_FRAME : Frame.SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED; } if (type != Frame.FULL_FRAME) { // Verify if locals are the same as in the previous frame. int frameIndex = 3; for (int i = 0; i < previousNumlocal && i < numLocal; i++) { if (currentFrame[frameIndex] != previousFrame[frameIndex]) { type = Frame.FULL_FRAME; break; } frameIndex++; } } switch (type) { case Frame.SAME_FRAME: stackMapTableEntries.putByte(offsetDelta); break; case Frame.SAME_LOCALS_1_STACK_ITEM_FRAME: stackMapTableEntries.putByte(Frame.SAME_LOCALS_1_STACK_ITEM_FRAME + offsetDelta); putAbstractTypes(3 + numLocal, 4 + numLocal); break; case Frame.SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED: stackMapTableEntries .putByte(Frame.SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED) .putShort(offsetDelta); putAbstractTypes(3 + numLocal, 4 + numLocal); break; case Frame.SAME_FRAME_EXTENDED: stackMapTableEntries.putByte(Frame.SAME_FRAME_EXTENDED).putShort(offsetDelta); break; case Frame.CHOP_FRAME: stackMapTableEntries .putByte(Frame.SAME_FRAME_EXTENDED + numLocalDelta) .putShort(offsetDelta); break; case Frame.APPEND_FRAME: stackMapTableEntries .putByte(Frame.SAME_FRAME_EXTENDED + numLocalDelta) .putShort(offsetDelta); putAbstractTypes(3 + previousNumlocal, 3 + numLocal); break; case Frame.FULL_FRAME: default: stackMapTableEntries.putByte(Frame.FULL_FRAME).putShort(offsetDelta).putShort(numLocal); putAbstractTypes(3, 3 + numLocal); stackMapTableEntries.putShort(numStack); putAbstractTypes(3 + numLocal, 3 + numLocal + numStack); break; } } /** * Puts some abstract types of {@link #currentFrame} in {@link #stackMapTableEntries} , using the * JVMS verification_type_info format used in StackMapTable attributes. * * @param start index of the first type in {@link #currentFrame} to write. * @param end index of last type in {@link #currentFrame} to write (exclusive). */ private void putAbstractTypes(final int start, final int end) { for (int i = start; i < end; ++i) { Frame.putAbstractType(symbolTable, currentFrame[i], stackMapTableEntries); } } /** * Puts the given public API frame element type in {@link #stackMapTableEntries} , using the JVMS * verification_type_info format used in StackMapTable attributes. * * @param type a frame element type described using the same format as in {@link * MethodVisitor#visitFrame}, i.e. either {@link Opcodes#TOP}, {@link Opcodes#INTEGER}, {@link * Opcodes#FLOAT}, {@link Opcodes#LONG}, {@link Opcodes#DOUBLE}, {@link Opcodes#NULL}, or * {@link Opcodes#UNINITIALIZED_THIS}, or the internal name of a class, or a Label designating * a NEW instruction (for uninitialized types). */ private void putFrameType(final Object type) { if (type instanceof Integer) { stackMapTableEntries.putByte(((Integer) type).intValue()); } else if (type instanceof String) { stackMapTableEntries .putByte(Frame.ITEM_OBJECT) .putShort(symbolTable.addConstantClass((String) type).index); } else { stackMapTableEntries.putByte(Frame.ITEM_UNINITIALIZED); ((Label) type).put(stackMapTableEntries); } } // ----------------------------------------------------------------------------------------------- // Utility methods // ----------------------------------------------------------------------------------------------- /** * Returns whether the attributes of this method can be copied from the attributes of the given * method (assuming there is no method visitor between the given ClassReader and this * MethodWriter). This method should only be called just after this MethodWriter has been created, * and before any content is visited. It returns true if the attributes corresponding to the * constructor arguments (at most a Signature, an Exception, a Deprecated and a Synthetic * attribute) are the same as the corresponding attributes in the given method. * * @param source the source ClassReader from which the attributes of this method might be copied. * @param hasSyntheticAttribute whether the method_info JVMS structure from which the attributes * of this method might be copied contains a Synthetic attribute. * @param hasDeprecatedAttribute whether the method_info JVMS structure from which the attributes * of this method might be copied contains a Deprecated attribute. * @param descriptorIndex the descriptor_index field of the method_info JVMS structure from which * the attributes of this method might be copied. * @param signatureIndex the constant pool index contained in the Signature attribute of the * method_info JVMS structure from which the attributes of this method might be copied, or 0. * @param exceptionsOffset the offset in 'source.b' of the Exceptions attribute of the method_info * JVMS structure from which the attributes of this method might be copied, or 0. * @return whether the attributes of this method can be copied from the attributes of the * method_info JVMS structure in 'source.b', between 'methodInfoOffset' and 'methodInfoOffset' * + 'methodInfoLength'. */ boolean canCopyMethodAttributes( final ClassReader source, final boolean hasSyntheticAttribute, final boolean hasDeprecatedAttribute, final int descriptorIndex, final int signatureIndex, final int exceptionsOffset) { // If the method descriptor has changed, with more locals than the max_locals field of the // original Code attribute, if any, then the original method attributes can't be copied. A // conservative check on the descriptor changes alone ensures this (being more precise is not // worth the additional complexity, because these cases should be rare -- if a transform changes // a method descriptor, most of the time it needs to change the method's code too). if (source != symbolTable.getSource() || descriptorIndex != this.descriptorIndex || signatureIndex != this.signatureIndex || hasDeprecatedAttribute != ((accessFlags & Opcodes.ACC_DEPRECATED) != 0)) { return false; } boolean needSyntheticAttribute = symbolTable.getMajorVersion() < Opcodes.V1_5 && (accessFlags & Opcodes.ACC_SYNTHETIC) != 0; if (hasSyntheticAttribute != needSyntheticAttribute) { return false; } if (exceptionsOffset == 0) { if (numberOfExceptions != 0) { return false; } } else if (source.readUnsignedShort(exceptionsOffset) == numberOfExceptions) { int currentExceptionOffset = exceptionsOffset + 2; for (int i = 0; i < numberOfExceptions; ++i) { if (source.readUnsignedShort(currentExceptionOffset) != exceptionIndexTable[i]) { return false; } currentExceptionOffset += 2; } } return true; } /** * Sets the source from which the attributes of this method will be copied. * * @param methodInfoOffset the offset in 'symbolTable.getSource()' of the method_info JVMS * structure from which the attributes of this method will be copied. * @param methodInfoLength the length in 'symbolTable.getSource()' of the method_info JVMS * structure from which the attributes of this method will be copied. */ void setMethodAttributesSource(final int methodInfoOffset, final int methodInfoLength) { // Don't copy the attributes yet, instead store their location in the source class reader so // they can be copied later, in {@link #putMethodInfo}. Note that we skip the 6 header bytes // of the method_info JVMS structure. this.sourceOffset = methodInfoOffset + 6; this.sourceLength = methodInfoLength - 6; } /** * Returns the size of the method_info JVMS structure generated by this MethodWriter. Also add the * names of the attributes of this method in the constant pool. * * @return the size in bytes of the method_info JVMS structure. */ int computeMethodInfoSize() { // If this method_info must be copied from an existing one, the size computation is trivial. if (sourceOffset != 0) { // sourceLength excludes the first 6 bytes for access_flags, name_index and descriptor_index. return 6 + sourceLength; } // 2 bytes each for access_flags, name_index, descriptor_index and attributes_count. int size = 8; // For ease of reference, we use here the same attribute order as in Section 4.7 of the JVMS. if (code.length > 0) { if (code.length > 65535) { throw new MethodTooLargeException( symbolTable.getClassName(), name, descriptor, code.length); } symbolTable.addConstantUtf8(Constants.CODE); // The Code attribute has 6 header bytes, plus 2, 2, 4 and 2 bytes respectively for max_stack, // max_locals, code_length and attributes_count, plus the bytecode and the exception table. size += 16 + code.length + Handler.getExceptionTableSize(firstHandler); if (stackMapTableEntries != null) { boolean useStackMapTable = symbolTable.getMajorVersion() >= Opcodes.V1_6; symbolTable.addConstantUtf8(useStackMapTable ? Constants.STACK_MAP_TABLE : "StackMap"); // 6 header bytes and 2 bytes for number_of_entries. size += 8 + stackMapTableEntries.length; } if (lineNumberTable != null) { symbolTable.addConstantUtf8(Constants.LINE_NUMBER_TABLE); // 6 header bytes and 2 bytes for line_number_table_length. size += 8 + lineNumberTable.length; } if (localVariableTable != null) { symbolTable.addConstantUtf8(Constants.LOCAL_VARIABLE_TABLE); // 6 header bytes and 2 bytes for local_variable_table_length. size += 8 + localVariableTable.length; } if (localVariableTypeTable != null) { symbolTable.addConstantUtf8(Constants.LOCAL_VARIABLE_TYPE_TABLE); // 6 header bytes and 2 bytes for local_variable_type_table_length. size += 8 + localVariableTypeTable.length; } if (lastCodeRuntimeVisibleTypeAnnotation != null) { size += lastCodeRuntimeVisibleTypeAnnotation.computeAnnotationsSize( Constants.RUNTIME_VISIBLE_TYPE_ANNOTATIONS); } if (lastCodeRuntimeInvisibleTypeAnnotation != null) { size += lastCodeRuntimeInvisibleTypeAnnotation.computeAnnotationsSize( Constants.RUNTIME_INVISIBLE_TYPE_ANNOTATIONS); } if (firstCodeAttribute != null) { size += firstCodeAttribute.computeAttributesSize( symbolTable, code.data, code.length, maxStack, maxLocals); } } if (numberOfExceptions > 0) { symbolTable.addConstantUtf8(Constants.EXCEPTIONS); size += 8 + 2 * numberOfExceptions; } size += Attribute.computeAttributesSize(symbolTable, accessFlags, signatureIndex); size += AnnotationWriter.computeAnnotationsSize( lastRuntimeVisibleAnnotation, lastRuntimeInvisibleAnnotation, lastRuntimeVisibleTypeAnnotation, lastRuntimeInvisibleTypeAnnotation); if (lastRuntimeVisibleParameterAnnotations != null) { size += AnnotationWriter.computeParameterAnnotationsSize( Constants.RUNTIME_VISIBLE_PARAMETER_ANNOTATIONS, lastRuntimeVisibleParameterAnnotations, visibleAnnotableParameterCount == 0 ? lastRuntimeVisibleParameterAnnotations.length : visibleAnnotableParameterCount); } if (lastRuntimeInvisibleParameterAnnotations != null) { size += AnnotationWriter.computeParameterAnnotationsSize( Constants.RUNTIME_INVISIBLE_PARAMETER_ANNOTATIONS, lastRuntimeInvisibleParameterAnnotations, invisibleAnnotableParameterCount == 0 ? lastRuntimeInvisibleParameterAnnotations.length : invisibleAnnotableParameterCount); } if (defaultValue != null) { symbolTable.addConstantUtf8(Constants.ANNOTATION_DEFAULT); size += 6 + defaultValue.length; } if (parameters != null) { symbolTable.addConstantUtf8(Constants.METHOD_PARAMETERS); // 6 header bytes and 1 byte for parameters_count. size += 7 + parameters.length; } if (firstAttribute != null) { size += firstAttribute.computeAttributesSize(symbolTable); } return size; } /** * Puts the content of the method_info JVMS structure generated by this MethodWriter into the * given ByteVector. * * @param output where the method_info structure must be put. */ void putMethodInfo(final ByteVector output) { boolean useSyntheticAttribute = symbolTable.getMajorVersion() < Opcodes.V1_5; int mask = useSyntheticAttribute ? Opcodes.ACC_SYNTHETIC : 0; output.putShort(accessFlags & ~mask).putShort(nameIndex).putShort(descriptorIndex); // If this method_info must be copied from an existing one, copy it now and return early. if (sourceOffset != 0) { output.putByteArray(symbolTable.getSource().classFileBuffer, sourceOffset, sourceLength); return; } // For ease of reference, we use here the same attribute order as in Section 4.7 of the JVMS. int attributeCount = 0; if (code.length > 0) { ++attributeCount; } if (numberOfExceptions > 0) { ++attributeCount; } if ((accessFlags & Opcodes.ACC_SYNTHETIC) != 0 && useSyntheticAttribute) { ++attributeCount; } if (signatureIndex != 0) { ++attributeCount; } if ((accessFlags & Opcodes.ACC_DEPRECATED) != 0) { ++attributeCount; } if (lastRuntimeVisibleAnnotation != null) { ++attributeCount; } if (lastRuntimeInvisibleAnnotation != null) { ++attributeCount; } if (lastRuntimeVisibleParameterAnnotations != null) { ++attributeCount; } if (lastRuntimeInvisibleParameterAnnotations != null) { ++attributeCount; } if (lastRuntimeVisibleTypeAnnotation != null) { ++attributeCount; } if (lastRuntimeInvisibleTypeAnnotation != null) { ++attributeCount; } if (defaultValue != null) { ++attributeCount; } if (parameters != null) { ++attributeCount; } if (firstAttribute != null) { attributeCount += firstAttribute.getAttributeCount(); } // For ease of reference, we use here the same attribute order as in Section 4.7 of the JVMS. output.putShort(attributeCount); if (code.length > 0) { // 2, 2, 4 and 2 bytes respectively for max_stack, max_locals, code_length and // attributes_count, plus the bytecode and the exception table. int size = 10 + code.length + Handler.getExceptionTableSize(firstHandler); int codeAttributeCount = 0; if (stackMapTableEntries != null) { // 6 header bytes and 2 bytes for number_of_entries. size += 8 + stackMapTableEntries.length; ++codeAttributeCount; } if (lineNumberTable != null) { // 6 header bytes and 2 bytes for line_number_table_length. size += 8 + lineNumberTable.length; ++codeAttributeCount; } if (localVariableTable != null) { // 6 header bytes and 2 bytes for local_variable_table_length. size += 8 + localVariableTable.length; ++codeAttributeCount; } if (localVariableTypeTable != null) { // 6 header bytes and 2 bytes for local_variable_type_table_length. size += 8 + localVariableTypeTable.length; ++codeAttributeCount; } if (lastCodeRuntimeVisibleTypeAnnotation != null) { size += lastCodeRuntimeVisibleTypeAnnotation.computeAnnotationsSize( Constants.RUNTIME_VISIBLE_TYPE_ANNOTATIONS); ++codeAttributeCount; } if (lastCodeRuntimeInvisibleTypeAnnotation != null) { size += lastCodeRuntimeInvisibleTypeAnnotation.computeAnnotationsSize( Constants.RUNTIME_INVISIBLE_TYPE_ANNOTATIONS); ++codeAttributeCount; } if (firstCodeAttribute != null) { size += firstCodeAttribute.computeAttributesSize( symbolTable, code.data, code.length, maxStack, maxLocals); codeAttributeCount += firstCodeAttribute.getAttributeCount(); } output .putShort(symbolTable.addConstantUtf8(Constants.CODE)) .putInt(size) .putShort(maxStack) .putShort(maxLocals) .putInt(code.length) .putByteArray(code.data, 0, code.length); Handler.putExceptionTable(firstHandler, output); output.putShort(codeAttributeCount); if (stackMapTableEntries != null) { boolean useStackMapTable = symbolTable.getMajorVersion() >= Opcodes.V1_6; output .putShort( symbolTable.addConstantUtf8( useStackMapTable ? Constants.STACK_MAP_TABLE : "StackMap")) .putInt(2 + stackMapTableEntries.length) .putShort(stackMapTableNumberOfEntries) .putByteArray(stackMapTableEntries.data, 0, stackMapTableEntries.length); } if (lineNumberTable != null) { output .putShort(symbolTable.addConstantUtf8(Constants.LINE_NUMBER_TABLE)) .putInt(2 + lineNumberTable.length) .putShort(lineNumberTableLength) .putByteArray(lineNumberTable.data, 0, lineNumberTable.length); } if (localVariableTable != null) { output .putShort(symbolTable.addConstantUtf8(Constants.LOCAL_VARIABLE_TABLE)) .putInt(2 + localVariableTable.length) .putShort(localVariableTableLength) .putByteArray(localVariableTable.data, 0, localVariableTable.length); } if (localVariableTypeTable != null) { output .putShort(symbolTable.addConstantUtf8(Constants.LOCAL_VARIABLE_TYPE_TABLE)) .putInt(2 + localVariableTypeTable.length) .putShort(localVariableTypeTableLength) .putByteArray(localVariableTypeTable.data, 0, localVariableTypeTable.length); } if (lastCodeRuntimeVisibleTypeAnnotation != null) { lastCodeRuntimeVisibleTypeAnnotation.putAnnotations( symbolTable.addConstantUtf8(Constants.RUNTIME_VISIBLE_TYPE_ANNOTATIONS), output); } if (lastCodeRuntimeInvisibleTypeAnnotation != null) { lastCodeRuntimeInvisibleTypeAnnotation.putAnnotations( symbolTable.addConstantUtf8(Constants.RUNTIME_INVISIBLE_TYPE_ANNOTATIONS), output); } if (firstCodeAttribute != null) { firstCodeAttribute.putAttributes( symbolTable, code.data, code.length, maxStack, maxLocals, output); } } if (numberOfExceptions > 0) { output .putShort(symbolTable.addConstantUtf8(Constants.EXCEPTIONS)) .putInt(2 + 2 * numberOfExceptions) .putShort(numberOfExceptions); for (int exceptionIndex : exceptionIndexTable) { output.putShort(exceptionIndex); } } Attribute.putAttributes(symbolTable, accessFlags, signatureIndex, output); AnnotationWriter.putAnnotations( symbolTable, lastRuntimeVisibleAnnotation, lastRuntimeInvisibleAnnotation, lastRuntimeVisibleTypeAnnotation, lastRuntimeInvisibleTypeAnnotation, output); if (lastRuntimeVisibleParameterAnnotations != null) { AnnotationWriter.putParameterAnnotations( symbolTable.addConstantUtf8(Constants.RUNTIME_VISIBLE_PARAMETER_ANNOTATIONS), lastRuntimeVisibleParameterAnnotations, visibleAnnotableParameterCount == 0 ? lastRuntimeVisibleParameterAnnotations.length : visibleAnnotableParameterCount, output); } if (lastRuntimeInvisibleParameterAnnotations != null) { AnnotationWriter.putParameterAnnotations( symbolTable.addConstantUtf8(Constants.RUNTIME_INVISIBLE_PARAMETER_ANNOTATIONS), lastRuntimeInvisibleParameterAnnotations, invisibleAnnotableParameterCount == 0 ? lastRuntimeInvisibleParameterAnnotations.length : invisibleAnnotableParameterCount, output); } if (defaultValue != null) { output .putShort(symbolTable.addConstantUtf8(Constants.ANNOTATION_DEFAULT)) .putInt(defaultValue.length) .putByteArray(defaultValue.data, 0, defaultValue.length); } if (parameters != null) { output .putShort(symbolTable.addConstantUtf8(Constants.METHOD_PARAMETERS)) .putInt(1 + parameters.length) .putByte(parametersCount) .putByteArray(parameters.data, 0, parameters.length); } if (firstAttribute != null) { firstAttribute.putAttributes(symbolTable, output); } } /** * Collects the attributes of this method into the given set of attribute prototypes. * * @param attributePrototypes a set of attribute prototypes. */ final void collectAttributePrototypes(final Attribute.Set attributePrototypes) { attributePrototypes.addAttributes(firstAttribute); attributePrototypes.addAttributes(firstCodeAttribute); } }