Package org.objectweb.asm.commons

Class AnalyzerAdapter

java.lang.Object
org.objectweb.asm.MethodVisitor
org.objectweb.asm.commons.AnalyzerAdapter
public class AnalyzerAdapter extends MethodVisitor
A MethodVisitor that keeps track of stack map frame changes between visitFrame(int, int, Object[], int, Object[]) 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.

  • Field Details

    • locals

      public List<Object> locals
      The local variable slots for the 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 two elements, the second one being TOP). Reference types are represented by String objects (representing internal names, see Type.getInternalName()), and uninitialized types by Label objects (this label designates the NEW instruction that created this uninitialized value). This field is null for unreachable instructions.

    • stack

      public List<Object> stack
      The operand stack slots for the 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 two elements, the second one being TOP). Reference types are represented by String objects (representing internal names, see Type.getInternalName()), and uninitialized types by Label objects (this label designates the NEW instruction that created this uninitialized value). This field is null for unreachable instructions.

    • uninitializedTypes

      public Map<Object,Object> uninitializedTypes
      The uninitialized types in the current execution frame. This map associates internal names to Label objects (see Type.getInternalName()). 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 descriptor, MethodVisitor methodVisitor)
      Constructs a new AnalyzerAdapter. Subclasses must not use this constructor. Instead, they must use the AnalyzerAdapter(int, String, int, String, String, MethodVisitor) version.
      Parameters:
      owner - the owner's class name.
      access - the method's access flags (see Opcodes).
      name - the method's name.
      descriptor - the method's descriptor (see Type).
      methodVisitor - the method visitor to which this adapter delegates calls. May be null.
      Throws:
      IllegalStateException - If a subclass calls this constructor.

    • AnalyzerAdapter

      protected AnalyzerAdapter(int api, String owner, int access, String name, String descriptor, MethodVisitor methodVisitor)
      Constructs a new AnalyzerAdapter.
      Parameters:
      api - the ASM API version implemented by this visitor. Must be one of the ASMx values in Opcodes.
      owner - the owner's class name.
      access - the method's access flags (see Opcodes).
      name - the method's name.
      descriptor - the method's descriptor (see Type).
      methodVisitor - the method visitor to which this adapter delegates calls. May be null.

  • Method Details

    • visitFrame

      public void visitFrame(int type, int numLocal, Object[] local, int numStack, Object[] stack)
      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 Opcodes.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 ( numStack 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 ( numLocal 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 (numLocal 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 MethodVisitor
      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.
      numLocal - the number of local variables in the visited frame. Long and double values count for one variable.
      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, see Type.getInternalName()), and uninitialized types by Label objects (this label designates the NEW instruction that created this uninitialized value).
      numStack - the number of operand stack elements in the visited frame. Long and double values count for one stack element.
      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 class: MethodVisitor
      Visits a zero operand instruction.
      Overrides:
      visitInsn in class MethodVisitor
      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 class: MethodVisitor
      Visits an instruction with a single int operand.
      Overrides:
      visitIntInsn in class MethodVisitor
      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 varIndex)
      Description copied from class: MethodVisitor
      Visits a local variable instruction. A local variable instruction is an instruction that loads or stores the value of a local variable.
      Overrides:
      visitVarInsn in class MethodVisitor
      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.
      varIndex - 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 class: MethodVisitor
      Visits a type instruction. A type instruction is an instruction that takes the internal name of a class as parameter (see Type.getInternalName()).
      Overrides:
      visitTypeInsn in class MethodVisitor
      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 Type.getInternalName()).

    • visitFieldInsn

      public void visitFieldInsn(int opcode, String owner, String name, String descriptor)
      Description copied from class: MethodVisitor
      Visits a field instruction. A field instruction is an instruction that loads or stores the value of a field of an object.
      Overrides:
      visitFieldInsn in class MethodVisitor
      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 Type.getInternalName()).
      name - the field's name.
      descriptor - the field's descriptor (see Type).

    • visitMethodInsn

      public void visitMethodInsn(int opcodeAndSource, String owner, String name, String descriptor, boolean isInterface)
      Description copied from class: MethodVisitor
      Visits a method instruction. A method instruction is an instruction that invokes a method.
      Overrides:
      visitMethodInsn in class MethodVisitor
      Parameters:
      opcodeAndSource - the opcode of the type instruction to be visited. This opcode is either INVOKEVIRTUAL, INVOKESPECIAL, INVOKESTATIC or INVOKEINTERFACE.
      owner - the internal name of the method's owner class (see Type.getInternalName()).
      name - the method's name.
      descriptor - the method's descriptor (see Type).
      isInterface - if the method's owner class is an interface.

    • visitInvokeDynamicInsn

      public void visitInvokeDynamicInsn(String name, String descriptor, Handle bootstrapMethodHandle, Object... bootstrapMethodArguments)
      Description copied from class: MethodVisitor
      Visits an invokedynamic instruction.
      Overrides:
      visitInvokeDynamicInsn in class MethodVisitor
      Parameters:
      name - the method's name.
      descriptor - the method's descriptor (see Type).
      bootstrapMethodHandle - the bootstrap method.
      bootstrapMethodArguments - the bootstrap method constant arguments. Each argument must be an Integer, Float, Long, Double, String, Type, Handle or ConstantDynamic value. This method is allowed to modify the content of the array so a caller should expect that this array may change.

    • visitJumpInsn

      public void visitJumpInsn(int opcode, Label label)
      Description copied from class: MethodVisitor
      Visits a jump instruction. A jump instruction is an instruction that may jump to another instruction.
      Overrides:
      visitJumpInsn in class MethodVisitor
      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 class: MethodVisitor
      Visits a label. A label designates the instruction that will be visited just after it.
      Overrides:
      visitLabel in class MethodVisitor
      Parameters:
      label - a Label object.

    • visitLdcInsn

      public void visitLdcInsn(Object value)
      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 if (cst instanceof ConstantDynamic) {
     // ...
 } else {
     // throw an exception
 }
      Overrides:
      visitLdcInsn in class MethodVisitor
      Parameters:
      value - 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, a Type of METHOD sort for MethodType, a Handle for MethodHandle constants, for classes whose version is 51 or a ConstantDynamic for a constant dynamic for classes whose version is 55.

    • visitIincInsn

      public void visitIincInsn(int varIndex, int increment)
      Description copied from class: MethodVisitor
      Visits an IINC instruction.
      Overrides:
      visitIincInsn in class MethodVisitor
      Parameters:
      varIndex - 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 class: MethodVisitor
      Visits a TABLESWITCH instruction.
      Overrides:
      visitTableSwitchInsn in class MethodVisitor
      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 class: MethodVisitor
      Visits a LOOKUPSWITCH instruction.
      Overrides:
      visitLookupSwitchInsn in class MethodVisitor
      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 descriptor, int numDimensions)
      Description copied from class: MethodVisitor
      Visits a MULTIANEWARRAY instruction.
      Overrides:
      visitMultiANewArrayInsn in class MethodVisitor
      Parameters:
      descriptor - an array type descriptor (see Type).
      numDimensions - the number of dimensions of the array to allocate.

    • visitLocalVariable

      public void visitLocalVariable(String name, String descriptor, String signature, Label start, Label end, int index)
      Description copied from class: MethodVisitor
      Visits a local variable declaration.
      Overrides:
      visitLocalVariable in class MethodVisitor
      Parameters:
      name - the name of a local variable.
      descriptor - 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.

    • visitMaxs

      public void visitMaxs(int maxStack, int maxLocals)
      Description copied from class: MethodVisitor
      Visits the maximum stack size and the maximum number of local variables of the method.
      Overrides:
      visitMaxs in class MethodVisitor
      Parameters:
      maxStack - maximum stack size of the method.
      maxLocals - maximum number of local variables for the method.