org.glassfish.pfl.objectweb.asm.commons

Class AnalyzerAdapter

java.lang.Object

org.glassfish.pfl.objectweb.asm.MethodAdapter

org.glassfish.pfl.objectweb.asm.commons.AnalyzerAdapter

All Implemented Interfaces:

MethodVisitor

public class AnalyzerAdapter
extends MethodAdapter

A MethodAdapter that keeps track of stack map frame changes between visitFrame calls. This adapter must be used with the org.objectweb.asm.ClassReader#EXPAND_FRAMES option. Each visitX instruction delegates to the next visitor in the chain, if any, and then simulates the effect of this instruction on the stack map frame, represented by locals and stack. The next visitor in the chain can get the state of the stack map frame before each instruction by reading the value of these fields in its visitX methods (this requires a reference to the AnalyzerAdapter that is before it in the chain). If this adapter is used with a class that does not contain stack map table attributes (i.e., pre Java 6 classes) then this adapter may not be able to compute the stack map frame for each instruction. In this case no exception is thrown but the locals and stack fields will be null for these instructions.

Author:

Eric Bruneton

Field Summary

Fields

Modifier and Type	Field and Description
List	locals List of the local variable slots for current execution frame.
List	stack List of the operand stack slots for current execution frame.
Map	uninitializedTypes Information about uninitialized types in the current execution frame.

Fields inherited from class org.glassfish.pfl.objectweb.asm.MethodAdapter

mv

Constructor Summary

Constructors

Constructor and Description
AnalyzerAdapter(String owner, int access, String name, String desc, MethodVisitor mv) Creates a new AnalyzerAdapter.

Method Summary

Methods

Modifier and Type	Method and Description
void	visitFieldInsn(int opcode, String owner, String name, String desc) Visits a field instruction.
void	visitFrame(int type, int nLocal, Object[] local, int nStack, Object[] stack) Visits the current state of the local variables and operand stack elements.
void	visitIincInsn(int var, int increment) Visits an IINC instruction.
void	visitInsn(int opcode) Visits a zero operand instruction.
void	visitIntInsn(int opcode, int operand) Visits an instruction with a single int operand.
void	visitJumpInsn(int opcode, Label label) Visits a jump instruction.
void	visitLabel(Label label) Visits a label.
void	visitLdcInsn(Object cst) Visits a LDC instruction.
void	visitLookupSwitchInsn(Label dflt, int[] keys, Label[] labels) Visits a LOOKUPSWITCH instruction.
void	visitMaxs(int maxStack, int maxLocals) Visits the maximum stack size and the maximum number of local variables of the method.
void	visitMethodInsn(int opcode, String owner, String name, String desc) Visits a method instruction.
void	visitMultiANewArrayInsn(String desc, int dims) Visits a MULTIANEWARRAY instruction.
void	visitTableSwitchInsn(int min, int max, Label dflt, Label[] labels) Visits a TABLESWITCH instruction.
void	visitTypeInsn(int opcode, String type) Visits a type instruction.
void	visitVarInsn(int opcode, int var) Visits a local variable instruction.

Methods inherited from class org.glassfish.pfl.objectweb.asm.MethodAdapter

visitAnnotation, visitAnnotationDefault, visitAttribute, visitCode, visitEnd, visitLineNumber, visitLocalVariable, visitParameterAnnotation, visitTryCatchBlock

Methods inherited from class java.lang.Object

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

Field Detail

locals

public List locals

List of the local variable slots for current execution frame. 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 two elements, the second one being TOP). 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). This field is null for unreacheable instructions.

stack

public List stack

List of the operand stack slots for current execution frame. 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 two elements, the second one being TOP). 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). This field is null for unreacheable instructions.

uninitializedTypes

public Map uninitializedTypes

Information about uninitialized types in the current execution frame. This map associates internal names to Label objects. Each label designates a NEW instruction that created the currently uninitialized types, and the associated internal name represents the NEW operand, i.e. the final, initialized type value.

Constructor Detail

AnalyzerAdapter

public AnalyzerAdapter(String owner,
               int access,
               String name,
               String desc,
               MethodVisitor mv)

Creates a new AnalyzerAdapter.

Parameters:

owner - the owner's class name.

access - the method's access flags (see Opcodes).

name - the method's name.

desc - the method's descriptor (see Type).

mv - the method visitor to which this adapter delegates calls. May be null.

Method Detail

visitFrame

public void visitFrame(int type,
              int nLocal,
              Object[] local,
              int nStack,
              Object[] stack)

Description copied from interface: 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.

Packed frames are basically "deltas" from the state of the previous frame (very first frame is implicitly defined by the method's parameters and access flags):

• 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.

Specified by:

visitFrame in interface MethodVisitor

Overrides:

visitFrame in class MethodAdapter

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.

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

local - 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).

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

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

visitInsn

public void visitInsn(int opcode)

Description copied from interface: MethodVisitor

Visits a zero operand instruction.

Specified by:

visitInsn in interface MethodVisitor

Overrides:

visitInsn in class MethodAdapter

Parameters:

opcode - the opcode of the instruction to be visited. This opcode is either NOP, ACONST_NULL, ICONST_M1, ICONST_0, ICONST_1, ICONST_2, ICONST_3, ICONST_4, ICONST_5, LCONST_0, LCONST_1, FCONST_0, FCONST_1, FCONST_2, DCONST_0, DCONST_1, IALOAD, LALOAD, FALOAD, DALOAD, AALOAD, BALOAD, CALOAD, SALOAD, IASTORE, LASTORE, FASTORE, DASTORE, AASTORE, BASTORE, CASTORE, SASTORE, POP, POP2, DUP, DUP_X1, DUP_X2, DUP2, DUP2_X1, DUP2_X2, SWAP, IADD, LADD, FADD, DADD, ISUB, LSUB, FSUB, DSUB, IMUL, LMUL, FMUL, DMUL, IDIV, LDIV, FDIV, DDIV, IREM, LREM, FREM, DREM, INEG, LNEG, FNEG, DNEG, ISHL, LSHL, ISHR, LSHR, IUSHR, LUSHR, IAND, LAND, IOR, LOR, IXOR, LXOR, I2L, I2F, I2D, L2I, L2F, L2D, F2I, F2L, F2D, D2I, D2L, D2F, I2B, I2C, I2S, LCMP, FCMPL, FCMPG, DCMPL, DCMPG, IRETURN, LRETURN, FRETURN, DRETURN, ARETURN, RETURN, ARRAYLENGTH, ATHROW, MONITORENTER, or MONITOREXIT.

visitIntInsn

public void visitIntInsn(int opcode,
                int operand)

Description copied from interface: MethodVisitor

Visits an instruction with a single int operand.

Specified by:

visitIntInsn in interface MethodVisitor

Overrides:

visitIntInsn in class MethodAdapter

Parameters:

opcode - the opcode of the instruction to be visited. This opcode is either BIPUSH, SIPUSH or NEWARRAY.

operand - the operand of the instruction to be visited.
When opcode is BIPUSH, operand value should be between Byte.MIN_VALUE and Byte.MAX_VALUE.
When opcode is SIPUSH, operand value should be between Short.MIN_VALUE and Short.MAX_VALUE.
When opcode is NEWARRAY, operand value should be one of Opcodes.T_BOOLEAN, Opcodes.T_CHAR, Opcodes.T_FLOAT, Opcodes.T_DOUBLE, Opcodes.T_BYTE, Opcodes.T_SHORT, Opcodes.T_INT or Opcodes.T_LONG.

visitVarInsn

public void visitVarInsn(int opcode,
                int var)

Description copied from interface: MethodVisitor

Visits a local variable instruction. A local variable instruction is an instruction that loads or stores the value of a local variable.

Specified by:

visitVarInsn in interface MethodVisitor

Overrides:

visitVarInsn in class MethodAdapter

Parameters:

opcode - the opcode of the local variable instruction to be visited. This opcode is either ILOAD, LLOAD, FLOAD, DLOAD, ALOAD, ISTORE, LSTORE, FSTORE, DSTORE, ASTORE or RET.

var - the operand of the instruction to be visited. This operand is the index of a local variable.

visitTypeInsn

public void visitTypeInsn(int opcode,
                 String type)

Description copied from interface: MethodVisitor

Visits a type instruction. A type instruction is an instruction that takes the internal name of a class as parameter.

Specified by:

visitTypeInsn in interface MethodVisitor

Overrides:

visitTypeInsn in class MethodAdapter

Parameters:

opcode - the opcode of the type instruction to be visited. This opcode is either NEW, ANEWARRAY, CHECKCAST or INSTANCEOF.

type - the operand of the instruction to be visited. This operand must be the internal name of an object or array class (see getInternalName).

visitFieldInsn

public void visitFieldInsn(int opcode,
                  String owner,
                  String name,
                  String desc)

Description copied from interface: MethodVisitor

Visits a field instruction. A field instruction is an instruction that loads or stores the value of a field of an object.

Specified by:

visitFieldInsn in interface MethodVisitor

Overrides:

visitFieldInsn in class MethodAdapter

Parameters:

opcode - the opcode of the type instruction to be visited. This opcode is either GETSTATIC, PUTSTATIC, GETFIELD or PUTFIELD.

owner - the internal name of the field's owner class (see getInternalName).

name - the field's name.

desc - the field's descriptor (see Type).

visitMethodInsn

public void visitMethodInsn(int opcode,
                   String owner,
                   String name,
                   String desc)

Description copied from interface: MethodVisitor

Visits a method instruction. A method instruction is an instruction that invokes a method.

Specified by:

visitMethodInsn in interface MethodVisitor

Overrides:

visitMethodInsn in class MethodAdapter

Parameters:

opcode - the opcode of the type instruction to be visited. This opcode is either INVOKEVIRTUAL, INVOKESPECIAL, INVOKESTATIC, INVOKEINTERFACE or INVOKEDYNAMIC.

owner - the internal name of the method's owner class (see getInternalName) or org.objectweb.asm.Opcodes#INVOKEDYNAMIC_OWNER.

name - the method's name.

desc - the method's descriptor (see Type).

visitJumpInsn

public void visitJumpInsn(int opcode,
                 Label label)

Description copied from interface: MethodVisitor

Visits a jump instruction. A jump instruction is an instruction that may jump to another instruction.

Specified by:

visitJumpInsn in interface MethodVisitor

Overrides:

visitJumpInsn in class MethodAdapter

Parameters:

opcode - the opcode of the type instruction to be visited. This opcode is either IFEQ, IFNE, IFLT, IFGE, IFGT, IFLE, IF_ICMPEQ, IF_ICMPNE, IF_ICMPLT, IF_ICMPGE, IF_ICMPGT, IF_ICMPLE, IF_ACMPEQ, IF_ACMPNE, GOTO, JSR, IFNULL or IFNONNULL.

label - the operand of the instruction to be visited. This operand is a label that designates the instruction to which the jump instruction may jump.

visitLabel

public void visitLabel(Label label)

Description copied from interface: MethodVisitor

Visits a label. A label designates the instruction that will be visited just after it.

Specified by:

visitLabel in interface MethodVisitor

Overrides:

visitLabel in class MethodAdapter

Parameters:

label - a Label object.

visitLdcInsn

public void visitLdcInsn(Object cst)

Description copied from interface: MethodVisitor

Visits a LDC instruction.

Specified by:

visitLdcInsn in interface MethodVisitor

Overrides:

visitLdcInsn in class MethodAdapter

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 (or a Type for .class constants, for classes whose version is 49.0 or more).

visitIincInsn

public void visitIincInsn(int var,
                 int increment)

Description copied from interface: MethodVisitor

Visits an IINC instruction.

Specified by:

visitIincInsn in interface MethodVisitor

Overrides:

visitIincInsn in class MethodAdapter

Parameters:

var - index of the local variable to be incremented.

increment - amount to increment the local variable by.

visitTableSwitchInsn

public void visitTableSwitchInsn(int min,
                        int max,
                        Label dflt,
                        Label[] labels)

Description copied from interface: MethodVisitor

Visits a TABLESWITCH instruction.

Specified by:

visitTableSwitchInsn in interface MethodVisitor

Overrides:

visitTableSwitchInsn in class MethodAdapter

Parameters:

min - the minimum key value.

max - the maximum key value.

dflt - beginning of the default handler block.

labels - beginnings of the handler blocks. labels[i] is the beginning of the handler block for the min + i key.

visitLookupSwitchInsn

public void visitLookupSwitchInsn(Label dflt,
                         int[] keys,
                         Label[] labels)

Description copied from interface: MethodVisitor

Visits a LOOKUPSWITCH instruction.

Specified by:

visitLookupSwitchInsn in interface MethodVisitor

Overrides:

visitLookupSwitchInsn in class MethodAdapter

Parameters:

dflt - beginning of the default handler block.

keys - the values of the keys.

labels - beginnings of the handler blocks. labels[i] is the beginning of the handler block for the keys[i] key.

visitMultiANewArrayInsn

public void visitMultiANewArrayInsn(String desc,
                           int dims)

Description copied from interface: MethodVisitor

Visits a MULTIANEWARRAY instruction.

Specified by:

visitMultiANewArrayInsn in interface MethodVisitor

Overrides:

visitMultiANewArrayInsn in class MethodAdapter

Parameters:

desc - an array type descriptor (see Type).

dims - number of dimensions of the array to allocate.

visitMaxs

public void visitMaxs(int maxStack,
             int maxLocals)

Description copied from interface: MethodVisitor

Visits the maximum stack size and the maximum number of local variables of the method.

Specified by:

visitMaxs in interface MethodVisitor

Overrides:

visitMaxs in class MethodAdapter

Parameters:

maxStack - maximum stack size of the method.

maxLocals - maximum number of local variables for the method.