org.objectweb.asm.optimizer

Class MethodOptimizer

java.lang.Object

org.objectweb.asm.MethodVisitor

org.objectweb.asm.commons.LocalVariablesSorter

org.objectweb.asm.commons.RemappingMethodAdapter

org.objectweb.asm.optimizer.MethodOptimizer

All Implemented Interfaces:

Opcodes

public class MethodOptimizer
extends RemappingMethodAdapter
implements Opcodes

A MethodVisitor that renames fields and methods, and removes debug info.

Author:

Eugene Kuleshov

Field Summary

Fields inherited from class org.objectweb.asm.commons.RemappingMethodAdapter

remapper

Fields inherited from class org.objectweb.asm.commons.LocalVariablesSorter

firstLocal, nextLocal

Fields inherited from class org.objectweb.asm.MethodVisitor

api, mv

Fields inherited from interface org.objectweb.asm.Opcodes

AALOAD, AASTORE, ACC_ABSTRACT, ACC_ANNOTATION, ACC_BRIDGE, ACC_DEPRECATED, ACC_ENUM, ACC_FINAL, ACC_INTERFACE, ACC_MANDATED, ACC_NATIVE, ACC_PRIVATE, ACC_PROTECTED, ACC_PUBLIC, ACC_STATIC, ACC_STRICT, ACC_SUPER, ACC_SYNCHRONIZED, ACC_SYNTHETIC, ACC_TRANSIENT, ACC_VARARGS, ACC_VOLATILE, ACONST_NULL, ALOAD, ANEWARRAY, ARETURN, ARRAYLENGTH, ASM4, ASM5, ASTORE, ATHROW, BALOAD, BASTORE, BIPUSH, CALOAD, CASTORE, CHECKCAST, D2F, D2I, D2L, DADD, DALOAD, DASTORE, DCMPG, DCMPL, DCONST_0, DCONST_1, DDIV, DLOAD, DMUL, DNEG, DOUBLE, DREM, DRETURN, DSTORE, DSUB, DUP, DUP_X1, DUP_X2, DUP2, DUP2_X1, DUP2_X2, F_APPEND, F_CHOP, F_FULL, F_NEW, F_SAME, F_SAME1, F2D, F2I, F2L, FADD, FALOAD, FASTORE, FCMPG, FCMPL, FCONST_0, FCONST_1, FCONST_2, FDIV, FLOAD, FLOAT, FMUL, FNEG, FREM, FRETURN, FSTORE, FSUB, GETFIELD, GETSTATIC, GOTO, H_GETFIELD, H_GETSTATIC, H_INVOKEINTERFACE, H_INVOKESPECIAL, H_INVOKESTATIC, H_INVOKEVIRTUAL, H_NEWINVOKESPECIAL, H_PUTFIELD, H_PUTSTATIC, I2B, I2C, I2D, I2F, I2L, I2S, IADD, IALOAD, IAND, IASTORE, ICONST_0, ICONST_1, ICONST_2, ICONST_3, ICONST_4, ICONST_5, ICONST_M1, IDIV, IF_ACMPEQ, IF_ACMPNE, IF_ICMPEQ, IF_ICMPGE, IF_ICMPGT, IF_ICMPLE, IF_ICMPLT, IF_ICMPNE, IFEQ, IFGE, IFGT, IFLE, IFLT, IFNE, IFNONNULL, IFNULL, IINC, ILOAD, IMUL, INEG, INSTANCEOF, INTEGER, INVOKEDYNAMIC, INVOKEINTERFACE, INVOKESPECIAL, INVOKESTATIC, INVOKEVIRTUAL, IOR, IREM, IRETURN, ISHL, ISHR, ISTORE, ISUB, IUSHR, IXOR, JSR, L2D, L2F, L2I, LADD, LALOAD, LAND, LASTORE, LCMP, LCONST_0, LCONST_1, LDC, LDIV, LLOAD, LMUL, LNEG, LONG, LOOKUPSWITCH, LOR, LREM, LRETURN, LSHL, LSHR, LSTORE, LSUB, LUSHR, LXOR, MONITORENTER, MONITOREXIT, MULTIANEWARRAY, NEW, NEWARRAY, NOP, NULL, POP, POP2, PUTFIELD, PUTSTATIC, RET, RETURN, SALOAD, SASTORE, SIPUSH, SWAP, T_BOOLEAN, T_BYTE, T_CHAR, T_DOUBLE, T_FLOAT, T_INT, T_LONG, T_SHORT, TABLESWITCH, TOP, UNINITIALIZED_THIS, V1_1, V1_2, V1_3, V1_4, V1_5, V1_6, V1_7, V1_8

Constructor Summary

Constructors

Constructor and Description
MethodOptimizer(ClassOptimizer classOptimizer, int access, String desc, MethodVisitor mv, Remapper remapper)

Method Summary

Methods

Modifier and Type	Method and Description
AnnotationVisitor	visitAnnotation(String desc, boolean visible) Visits an annotation of this method.
AnnotationVisitor	visitAnnotationDefault() Visits the default value of this annotation interface method.
void	visitAttribute(Attribute attr) Visits a non standard attribute of this method.
void	visitFrame(int type, int local, Object[] local2, int stack, Object[] stack2) Visits the current state of the local variables and operand stack elements.
void	visitLdcInsn(Object cst) Visits a LDC instruction.
void	visitLineNumber(int line, Label start) Visits a line number declaration.
void	visitLocalVariable(String name, String desc, String signature, Label start, Label end, int index) Visits a local variable declaration.
void	visitParameter(String name, int access) Visits a parameter of this method.
AnnotationVisitor	visitParameterAnnotation(int parameter, String desc, boolean visible) Visits an annotation of a parameter this method.
AnnotationVisitor	visitTypeAnnotation(int typeRef, TypePath typePath, String desc, boolean visible) Visits an annotation on a type in the method signature.

Methods inherited from class org.objectweb.asm.commons.RemappingMethodAdapter

visitFieldInsn, visitInsnAnnotation, visitInvokeDynamicInsn, visitLocalVariableAnnotation, visitMethodInsn, visitMultiANewArrayInsn, visitTryCatchAnnotation, visitTryCatchBlock, visitTypeInsn

Methods inherited from class org.objectweb.asm.commons.LocalVariablesSorter

newLocal, newLocalMapping, setLocalType, updateNewLocals, visitIincInsn, visitMaxs, visitVarInsn

Methods inherited from class org.objectweb.asm.MethodVisitor

visitCode, visitEnd, visitInsn, visitIntInsn, visitJumpInsn, visitLabel, visitLookupSwitchInsn, visitTableSwitchInsn

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MethodOptimizer

public MethodOptimizer(ClassOptimizer classOptimizer,
               int access,
               String desc,
               MethodVisitor mv,
               Remapper remapper)

Method Detail

visitParameter

public void visitParameter(String name,
                  int access)

Description copied from class: MethodVisitor

Visits a parameter of this method.

Overrides:

visitParameter in class MethodVisitor

Parameters:

name - parameter name or null if none is provided.

access - the parameter's access flags, only ACC_FINAL, ACC_SYNTHETIC or/and ACC_MANDATED are allowed (see Opcodes).

visitAnnotationDefault

public AnnotationVisitor visitAnnotationDefault()

Description copied from class: MethodVisitor

Visits the default value of this annotation interface method.

Overrides:

visitAnnotationDefault in class RemappingMethodAdapter

Returns:

a visitor to the visit the actual default value of this annotation interface method, or null if this visitor is not interested in visiting this default value. The 'name' parameters passed to the methods of this annotation visitor are ignored. Moreover, exacly one visit method must be called on this annotation visitor, followed by visitEnd.

visitAnnotation

public AnnotationVisitor visitAnnotation(String desc,
                                boolean visible)

Description copied from class: MethodVisitor

Visits an annotation of this method.

Overrides:

visitAnnotation in class RemappingMethodAdapter

Parameters:

desc - the class descriptor of the annotation class.

visible - true if the annotation is visible at runtime.

Returns:

a visitor to visit the annotation values, or null if this visitor is not interested in visiting this annotation.

visitTypeAnnotation

public AnnotationVisitor visitTypeAnnotation(int typeRef,
                                    TypePath typePath,
                                    String desc,
                                    boolean visible)

Description copied from class: MethodVisitor

Visits an annotation on a type in the method signature.

Overrides:

visitTypeAnnotation in class RemappingMethodAdapter

Parameters:

typeRef - a reference to the annotated type. The sort of this type reference must be METHOD_TYPE_PARAMETER, METHOD_TYPE_PARAMETER_BOUND, METHOD_RETURN, METHOD_RECEIVER, METHOD_FORMAL_PARAMETER or THROWS. See TypeReference.

typePath - the path to the annotated type argument, wildcard bound, array element type, or static inner type within 'typeRef'. May be null if the annotation targets 'typeRef' as a whole.

desc - the class descriptor of the annotation class.

visible - true if the annotation is visible at runtime.

Returns:

a visitor to visit the annotation values, or null if this visitor is not interested in visiting this annotation.

visitParameterAnnotation

public AnnotationVisitor visitParameterAnnotation(int parameter,
                                         String desc,
                                         boolean visible)

Description copied from class: MethodVisitor

Visits an annotation of a parameter this method.

Overrides:

visitParameterAnnotation in class RemappingMethodAdapter

Parameters:

parameter - the parameter index.

desc - the class descriptor of the annotation class.

visible - true if the annotation is visible at runtime.

Returns:

a visitor to visit the annotation values, or null if this visitor is not interested in visiting this annotation.

visitLocalVariable

public void visitLocalVariable(String name,
                      String desc,
                      String signature,
                      Label start,
                      Label end,
                      int index)

Description copied from class: MethodVisitor

Visits a local variable declaration.

Overrides:

visitLocalVariable in class RemappingMethodAdapter

Parameters:

name - the name of a local variable.

desc - the type descriptor of this local variable.

signature - the type signature of this local variable. May be null if the local variable type does not use generic types.

start - the first instruction corresponding to the scope of this local variable (inclusive).

end - the last instruction corresponding to the scope of this local variable (exclusive).

index - the local variable's index.

visitLineNumber

public void visitLineNumber(int line,
                   Label start)

Description copied from class: MethodVisitor

Visits a line number declaration.

Overrides:

visitLineNumber in class MethodVisitor

Parameters:

line - a line number. This number refers to the source file from which the class was compiled.

start - the first instruction corresponding to this line number.

visitFrame

public void visitFrame(int type,
              int local,
              Object[] local2,
              int stack,
              Object[] stack2)

Description copied from class: MethodVisitor

Visits the current state of the local variables and operand stack elements. This method must(*) be called just before any instruction i that follows an unconditional branch instruction such as GOTO or THROW, that is the target of a jump instruction, or that starts an exception handler block. The visited types must describe the values of the local variables and of the operand stack elements just before i is executed.

(*) this is mandatory only for classes whose version is greater than or equal to V1_6.

The frames of a method must be given either in expanded form, or in compressed form (all frames must use the same format, i.e. you must not mix expanded and compressed frames within a single method):

• In expanded form, all frames must have the F_NEW type.
• In compressed form, frames are basically "deltas" from the state of the previous frame:
  • Opcodes.F_SAME representing frame with exactly the same locals as the previous frame and with the empty stack.
  • Opcodes.F_SAME1 representing frame with exactly the same locals as the previous frame and with single value on the stack ( nStack is 1 and stack[0] contains value for the type of the stack item).
  • Opcodes.F_APPEND representing frame with current locals are the same as the locals in the previous frame, except that additional locals are defined (nLocal is 1, 2 or 3 and local elements contains values representing added types).
  • Opcodes.F_CHOP representing frame with current locals are the same as the locals in the previous frame, except that the last 1-3 locals are absent and with the empty stack (nLocals is 1, 2 or 3).
  • Opcodes.F_FULL representing complete frame data.

In both cases the first frame, corresponding to the method's parameters and access flags, is implicit and must not be visited. Also, it is illegal to visit two or more frames for the same code location (i.e., at least one instruction must be visited between two calls to visitFrame).

Overrides:

visitFrame in class RemappingMethodAdapter

Parameters:

type - the type of this stack map frame. Must be Opcodes.F_NEW for expanded frames, or Opcodes.F_FULL, Opcodes.F_APPEND, Opcodes.F_CHOP, Opcodes.F_SAME or Opcodes.F_APPEND, Opcodes.F_SAME1 for compressed frames.

local - the number of local variables in the visited frame.

local2 - the local variable types in this frame. This array must not be modified. Primitive types are represented by Opcodes.TOP, Opcodes.INTEGER, Opcodes.FLOAT, Opcodes.LONG, Opcodes.DOUBLE,Opcodes.NULL or Opcodes.UNINITIALIZED_THIS (long and double are represented by a single element). Reference types are represented by String objects (representing internal names), and uninitialized types by Label objects (this label designates the NEW instruction that created this uninitialized value).

stack - the number of operand stack elements in the visited frame.

stack2 - the operand stack types in this frame. This array must not be modified. Its content has the same format as the "local" array.

visitAttribute

public void visitAttribute(Attribute attr)

Description copied from class: MethodVisitor

Visits a non standard attribute of this method.

Overrides:

visitAttribute in class MethodVisitor

Parameters:

attr - an attribute.

visitLdcInsn

public void visitLdcInsn(Object cst)

Description copied from class: MethodVisitor

Visits a LDC instruction. Note that new constant types may be added in future versions of the Java Virtual Machine. To easily detect new constant types, implementations of this method should check for unexpected constant types, like this:

 if (cst instanceof Integer) {
     // ...
 } else if (cst instanceof Float) {
     // ...
 } else if (cst instanceof Long) {
     // ...
 } else if (cst instanceof Double) {
     // ...
 } else if (cst instanceof String) {
     // ...
 } else if (cst instanceof Type) {
     int sort = ((Type) cst).getSort();
     if (sort == Type.OBJECT) {
         // ...
     } else if (sort == Type.ARRAY) {
         // ...
     } else if (sort == Type.METHOD) {
         // ...
     } else {
         // throw an exception
     }
 } else if (cst instanceof Handle) {
     // ...
 } else {
     // throw an exception
 }
 

Overrides:

visitLdcInsn in class RemappingMethodAdapter

Parameters:

cst - the constant to be loaded on the stack. This parameter must be a non null Integer, a Float, a Long, a Double, a String, a Type of OBJECT or ARRAY sort for .class constants, for classes whose version is 49.0, a Type of METHOD sort or a Handle for MethodType and MethodHandle constants, for classes whose version is 51.0.