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// 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
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// THE POSSIBILITY OF SUCH DAMAGE.
package com.sun.xml.ws.org.objectweb.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 firstCodeAttribute;
// Other method_info attributes:
/** The number_of_exceptions field of the Exceptions attribute. */
private final int numberOfExceptions;
/** The exception_index_table array of the Exceptions attribute, or {@literal null}. */
private final int[] exceptionIndexTable;
/** The signature_index field of the Signature attribute. */
private final int signatureIndex;
/**
* The last runtime visible annotation of this method. The previous ones can be accessed with the
* {@link AnnotationWriter#previousAnnotation} field. May be {@literal null}.
*/
private AnnotationWriter lastRuntimeVisibleAnnotation;
/**
* The last runtime invisible annotation of this method. The previous ones can be accessed with
* the {@link AnnotationWriter#previousAnnotation} field. May be {@literal null}.
*/
private AnnotationWriter lastRuntimeInvisibleAnnotation;
/** The number of method parameters that can have runtime visible annotations, or 0. */
private int visibleAnnotableParameterCount;
/**
* The runtime visible parameter annotations of this method. Each array element contains the last
* annotation of a parameter (which can be {@literal null} - the previous ones can be accessed
* with the {@link AnnotationWriter#previousAnnotation} field). May be {@literal null}.
*/
private AnnotationWriter[] lastRuntimeVisibleParameterAnnotations;
/** The number of method parameters that can have runtime visible annotations, or 0. */
private int invisibleAnnotableParameterCount;
/**
* The runtime invisible parameter annotations of this method. Each array element contains the
* last annotation of a parameter (which can be {@literal null} - the previous ones can be
* accessed with the {@link AnnotationWriter#previousAnnotation} field). May be {@literal null}.
*/
private AnnotationWriter[] lastRuntimeInvisibleParameterAnnotations;
/**
* The last runtime visible type annotation of this method. The previous ones can be accessed with
* the {@link AnnotationWriter#previousAnnotation} field. May be {@literal null}.
*/
private AnnotationWriter lastRuntimeVisibleTypeAnnotation;
/**
* The last runtime invisible type annotation of this method. The previous ones can be accessed
* with the {@link AnnotationWriter#previousAnnotation} field. May be {@literal null}.
*/
private AnnotationWriter lastRuntimeInvisibleTypeAnnotation;
/** The default_value field of the AnnotationDefault attribute, or {@literal null}. */
private ByteVector defaultValue;
/** The parameters_count field of the MethodParameters attribute. */
private int parametersCount;
/** The 'parameters' array of the MethodParameters attribute, or {@literal null}. */
private ByteVector parameters;
/**
* The first non standard attribute of this method. 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);
}
}