Class AnalyzerAdapter

java.lang.Object
org.objectweb.asm.MethodAdapter
org.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 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 Details

    • 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 Details

    • 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 Details

    • 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 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.