AnalyzerAdapter (ASM 5.0.4 Documentation)
Date: 2015-09-18

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` 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 Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `List<Object>` | `locals` `List` of the local variable slots for current execution frame.
    `List<Object>` | `stack` `List` of the operand stack slots for current execution frame.
    `Map<Object,Object>` | `uninitializedTypes` Information about uninitialized types in the current execution frame.

    - ### Fields inherited from class org.objectweb.asm.MethodVisitor

      `api, mv`

  - ### Constructor Summary

    Constructors
    Modifier | Constructor and Description
    --- | ---
    `protected` | `AnalyzerAdapter(int api, String owner, int access, String name, String desc, MethodVisitor mv)` Creates a new `AnalyzerAdapter`.
    `` | `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` | `visitInvokeDynamicInsn(String name, String desc, Handle bsm, Object... bsmArgs)` Visits an invokedynamic instruction.
    `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)` Deprecated.
    `void` | `visitMethodInsn(int opcode, String owner, String name, String desc, boolean itf)` 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.objectweb.asm.MethodVisitor

      `visitAnnotation, visitAnnotationDefault, visitAttribute, visitCode, visitEnd, visitInsnAnnotation, visitLineNumber, visitLocalVariable, visitLocalVariableAnnotation, visitParameter, visitParameterAnnotation, visitTryCatchAnnotation, visitTryCatchBlock, visitTypeAnnotation`

    - ### Methods inherited from class java.lang.Object

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

- - ### Field Detail

    - #### locals

          public List<Object> 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 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 unreachable instructions.

    - #### stack

          public List<Object> 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 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 unreachable instructions.

    - #### uninitializedTypes

          public Map<Object,Object> 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`. 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.
        `desc` - the method's descriptor (see `Type`).
        `mv` - 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 desc,
                         MethodVisitor mv)

      Creates a new `AnalyzerAdapter`.
      Parameters:
        `api` - the ASM API version implemented by this visitor. Must be one of `Opcodes.ASM4` or `Opcodes.ASM5`.
        `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 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 `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.
        `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 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 var)

      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.
        `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 class: `MethodVisitor`
      Visits a type instruction. A type instruction is an instruction that takes the internal name of a class as parameter.
      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 `getInternalName`).

    - #### visitFieldInsn

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

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

    - #### visitMethodInsn

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

      Deprecated.
      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:
        `opcode` - 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 `getInternalName`).
        `name` - the method's name.
        `desc` - the method's descriptor (see `Type`).

    - #### visitMethodInsn

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

      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:
        `opcode` - 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 `getInternalName`).
        `name` - the method's name.
        `desc` - the method's descriptor (see `Type`).
        `itf` - if the method's owner class is an interface.

    - #### visitInvokeDynamicInsn

          public void visitInvokeDynamicInsn(String name,
                                    String desc,
                                    Handle bsm,
                                    Object... bsmArgs)

      Description copied from class: `MethodVisitor`
      Visits an invokedynamic instruction.
      Overrides:
        `visitInvokeDynamicInsn` in class `MethodVisitor`
      Parameters:
        `name` - the method's name.
        `desc` - the method's descriptor (see `Type`).
        `bsm` - the bootstrap method.
        `bsmArgs` - the bootstrap method constant arguments. Each argument must be an `Integer`, `Float`, `Long`, `Double`, `String`, `Type` or `Handle` 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 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 `MethodVisitor`
      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.

    - #### visitIincInsn

          public void visitIincInsn(int var,
                           int increment)

      Description copied from class: `MethodVisitor`
      Visits an IINC instruction.
      Overrides:
        `visitIincInsn` in class `MethodVisitor`
      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 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 desc,
                                     int dims)

      Description copied from class: `MethodVisitor`
      Visits a MULTIANEWARRAY instruction.
      Overrides:
        `visitMultiANewArrayInsn` in class `MethodVisitor`
      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 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.