Class BaseMachine

java.lang.Object
com.android.dx.cf.code.BaseMachine
All Implemented Interfaces:
Machine
Direct Known Subclasses:
ValueAwareMachine
public abstract class BaseMachine extends Object implements Machine
Base implementation of Machine.

Note: For the most part, the documentation for this class ignores the distinction between Type and TypeBearer.

  • Constructor Summary

    Constructors
    Constructor
    Description
    BaseMachine(Prototype prototype)
    Constructs an instance.

  • Method Summary

    Modifier and Type
    Method
    Description
    protected final void
    addResult(TypeBearer result)
    Adds an additional element to the list of results.
    protected final TypeBearer
    arg(int n)
    Gets the nth primary argument.
    protected final int
    argCount()
    Gets the number of primary arguments.
    protected final int
    argWidth()
    Gets the width of the arguments (where a category-2 value counts as two).
    final void
    auxCstArg(Constant cst)
    Indicates that there is an auxiliary (inline, not stack) object argument, with the value based on the given constant.
    final void
    auxInitValues(ArrayList<Constant> initValues)
    Indicates that there is an auxiliary (inline, not stack) argument consisting of a list of initial values for a newly created array.
    final void
    auxIntArg(int value)
    Indicates that there is an auxiliary (inline, not stack) argument of type int, with the given value.
    final void
    auxSwitchArg(SwitchList cases)
    Indicates that there is an auxiliary (inline, not stack) argument consisting of a switch* table.
    final void
    auxTargetArg(int target)
    Indicates that there is an auxiliary (inline, not stack) argument indicating a branch target.
    final void
    auxType(Type type)
    Indicates that the salient type of this operation is as given.
    final void
    clearArgs()
    Clears the regular and auxiliary arguments area.
    protected final void
    clearResult()
    Clears the results.
    protected final SwitchList
    getAuxCases()
    Gets the switch cases auxiliary argument.
    protected final Constant
    getAuxCst()
    Gets the constant auxiliary argument.
    protected final int
    getAuxInt()
    Gets the int auxiliary argument.
    protected final int
    getAuxTarget()
    Gets the branch target auxiliary argument.
    protected final Type
    getAuxType()
    Gets the type auxiliary argument.
    protected final ArrayList<Constant>
    getInitValues()
    Gets the init values auxiliary argument.
    protected final int
    getLocalIndex()
    Gets the last local index accessed.
    protected final boolean
    getLocalInfo()
    Gets whether the loaded local has info in the local variable table.
    protected final RegisterSpec
    getLocalTarget(boolean isMove)
    Gets the target local register spec of the current operation, if any.
    Prototype
    getPrototype()
    Gets the effective prototype of the method that this instance is being used for.
    final void
    localArg(Frame frame, int idx)
    Loads the local variable with the given index as the sole argument in the arguments area.
    final void
    localInfo(boolean local)
    Used to specify if a loaded local variable has info in the local variable table.
    final void
    localTarget(int idx, Type type, LocalItem local)
    Indicates that the target of this operation is the given local.
    final void
    popArgs(Frame frame, int count)
    Pops the given number of values from the stack (of either category), and store them in the arguments area, indicating that there are now that many arguments.
    void
    popArgs(Frame frame, Prototype prototype)
    Pops values from the stack of the types indicated by the given Prototype (popped in reverse of the argument order, so the first prototype argument type is for the deepest element of the stack), and store them in the arguments area, indicating that there are now that many arguments.
    final void
    popArgs(Frame frame, Type type)
    Pops a value from the stack of the indicated type, and store it in the arguments area, indicating that there are now that many arguments.
    final void
    popArgs(Frame frame, Type type1, Type type2)
    Pops values from the stack of the indicated types (popped in reverse argument order, so the first indicated type is for the deepest element of the stack), and store them in the arguments area, indicating that there are now that many arguments.
    final void
    popArgs(Frame frame, Type type1, Type type2, Type type3)
    Pops values from the stack of the indicated types (popped in reverse argument order, so the first indicated type is for the deepest element of the stack), and store them in the arguments area, indicating that there are now that many arguments.
    protected final TypeBearer
    result(int n)
    Gets the nth result value.
    protected final int
    resultCount()
    Gets the count of results.
    protected final int
    resultWidth()
    Gets the width of the results (where a category-2 value counts as two).
    protected final void
    setResult(TypeBearer result)
    Sets the results list to be the given single value.
    protected final void
    storeResults(Frame frame)
    Stores the results of the latest operation into the given frame.
    static void
    throwLocalMismatch(TypeBearer found, TypeBearer local)
    Throws an exception that indicates a mismatch in local variable types.

    Methods inherited from class Object

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

    Methods inherited from interface Machine

    run

  • Constructor Details

    • BaseMachine

      public BaseMachine(Prototype prototype)
      Constructs an instance.
      Parameters:
      prototype - non-null; the prototype for the associated method

  • Method Details

    • getPrototype

      public Prototype getPrototype()
      Gets the effective prototype of the method that this instance is being used for. The effective prototype includes an initial this argument for instance methods.
      Specified by:
      getPrototype in interface Machine
      Returns:
      non-null; the method prototype

    • clearArgs

      public final void clearArgs()
      Clears the regular and auxiliary arguments area.
      Specified by:
      clearArgs in interface Machine

    • popArgs

      public final void popArgs(Frame frame, int count)
      Pops the given number of values from the stack (of either category), and store them in the arguments area, indicating that there are now that many arguments. Also, clear the auxiliary arguments.
      Specified by:
      popArgs in interface Machine
      Parameters:
      frame - non-null; frame to operate on
      count - >= 0; number of values to pop

    • popArgs

      public void popArgs(Frame frame, Prototype prototype)
      Pops values from the stack of the types indicated by the given Prototype (popped in reverse of the argument order, so the first prototype argument type is for the deepest element of the stack), and store them in the arguments area, indicating that there are now that many arguments. Also, clear the auxiliary arguments.
      Specified by:
      popArgs in interface Machine
      Parameters:
      frame - non-null; frame to operate on
      prototype - non-null; prototype indicating arguments to pop

    • popArgs

      public final void popArgs(Frame frame, Type type)
      Description copied from interface: Machine
      Pops a value from the stack of the indicated type, and store it in the arguments area, indicating that there are now that many arguments. Also, clear the auxiliary arguments.
      Specified by:
      popArgs in interface Machine
      Parameters:
      frame - non-null; frame to operate on
      type - non-null; type of the argument

    • popArgs

      public final void popArgs(Frame frame, Type type1, Type type2)
      Pops values from the stack of the indicated types (popped in reverse argument order, so the first indicated type is for the deepest element of the stack), and store them in the arguments area, indicating that there are now that many arguments. Also, clear the auxiliary arguments.
      Specified by:
      popArgs in interface Machine
      Parameters:
      frame - non-null; frame to operate on
      type1 - non-null; type of the first argument
      type2 - non-null; type of the second argument

    • popArgs

      public final void popArgs(Frame frame, Type type1, Type type2, Type type3)
      Pops values from the stack of the indicated types (popped in reverse argument order, so the first indicated type is for the deepest element of the stack), and store them in the arguments area, indicating that there are now that many arguments. Also, clear the auxiliary arguments.
      Specified by:
      popArgs in interface Machine
      Parameters:
      frame - non-null; frame to operate on
      type1 - non-null; type of the first argument
      type2 - non-null; type of the second argument
      type3 - non-null; type of the third argument

    • localArg

      public final void localArg(Frame frame, int idx)
      Loads the local variable with the given index as the sole argument in the arguments area. Also, clear the auxiliary arguments.
      Specified by:
      localArg in interface Machine
      Parameters:
      frame - non-null; frame to operate on
      idx - >= 0; the local variable index

    • localInfo

      public final void localInfo(boolean local)
      Used to specify if a loaded local variable has info in the local variable table.
      Specified by:
      localInfo in interface Machine
      Parameters:
      local - true if local arg has info in local variable table

    • auxType

      public final void auxType(Type type)
      Indicates that the salient type of this operation is as given. This differentiates between, for example, the various arithmetic opcodes, which, by the time they hit a Machine are collapsed to the int variant. (See BytecodeArray.parseInstruction(int, BytecodeArray.Visitor) for details.)
      Specified by:
      auxType in interface Machine
      Parameters:
      type - non-null; the salient type of the upcoming operation

    • auxIntArg

      public final void auxIntArg(int value)
      Indicates that there is an auxiliary (inline, not stack) argument of type int, with the given value.

      Note: Perhaps unintuitively, the stack manipulation ops (e.g., dup and swap) use this to indicate the result stack pattern with a straightforward hex encoding of the push order starting with least-significant nibbles getting pushed first). For example, an all-category-1 dup2_x1 sets this to 0x12312, and the other form of that op sets this to 0x121.

      Also Note: For switch* instructions, this is used to indicate the padding value (which is only useful for verification).

      Specified by:
      auxIntArg in interface Machine
      Parameters:
      value - the argument value

    • auxCstArg

      public final void auxCstArg(Constant cst)
      Indicates that there is an auxiliary (inline, not stack) object argument, with the value based on the given constant.

      Note: Some opcodes use both int and constant auxiliary arguments.

      Specified by:
      auxCstArg in interface Machine
      Parameters:
      cst - non-null; the constant containing / referencing the value

    • auxTargetArg

      public final void auxTargetArg(int target)
      Indicates that there is an auxiliary (inline, not stack) argument indicating a branch target.
      Specified by:
      auxTargetArg in interface Machine
      Parameters:
      target - the argument value

    • auxSwitchArg

      public final void auxSwitchArg(SwitchList cases)
      Indicates that there is an auxiliary (inline, not stack) argument consisting of a switch* table.

      Note: This is generally used in conjunction with Machine.auxIntArg(int) (which holds the padding).

      Specified by:
      auxSwitchArg in interface Machine
      Parameters:
      cases - non-null; the list of key-target pairs, plus the default target

    • auxInitValues

      public final void auxInitValues(ArrayList<Constant> initValues)
      Indicates that there is an auxiliary (inline, not stack) argument consisting of a list of initial values for a newly created array.
      Specified by:
      auxInitValues in interface Machine
      Parameters:
      initValues - non-null; the list of constant values to initialize the array

    • localTarget

      public final void localTarget(int idx, Type type, LocalItem local)
      Indicates that the target of this operation is the given local.
      Specified by:
      localTarget in interface Machine
      Parameters:
      idx - >= 0; the local variable index
      type - non-null; the type of the local
      local - null-ok; the name and signature of the local, if known

    • argCount

      protected final int argCount()
      Gets the number of primary arguments.
      Returns:
      >= 0; the number of primary arguments

    • argWidth

      protected final int argWidth()
      Gets the width of the arguments (where a category-2 value counts as two).
      Returns:
      >= 0; the argument width

    • arg

      protected final TypeBearer arg(int n)
      Gets the nth primary argument.
      Parameters:
      n - >= 0, < argCount(); which argument
      Returns:
      non-null; the indicated argument

    • getAuxType

      protected final Type getAuxType()
      Gets the type auxiliary argument.
      Returns:
      null-ok; the salient type

    • getAuxInt

      protected final int getAuxInt()
      Gets the int auxiliary argument.
      Returns:
      the argument value

    • getAuxCst

      protected final Constant getAuxCst()
      Gets the constant auxiliary argument.
      Returns:
      null-ok; the argument value

    • getAuxTarget

      protected final int getAuxTarget()
      Gets the branch target auxiliary argument.
      Returns:
      the argument value

    • getAuxCases

      protected final SwitchList getAuxCases()
      Gets the switch cases auxiliary argument.
      Returns:
      null-ok; the argument value

    • getInitValues

      protected final ArrayList<Constant> getInitValues()
      Gets the init values auxiliary argument.
      Returns:
      null-ok; the argument value

    • getLocalIndex

      protected final int getLocalIndex()
      Gets the last local index accessed.
      Returns:
      >= -1; the salient local index or -1 if none was set since the last time clearArgs() was called

    • getLocalInfo

      protected final boolean getLocalInfo()
      Gets whether the loaded local has info in the local variable table.
      Returns:
      true if local arg has info in the local variable table

    • getLocalTarget

      protected final RegisterSpec getLocalTarget(boolean isMove)
      Gets the target local register spec of the current operation, if any. The local target spec is the combination of the values indicated by a previous call to localTarget with the type of what should be the sole result set by a call to setResult(TypeBearer) (or the combination clearResult() then addResult(TypeBearer).
      Parameters:
      isMove - true if the operation being performed on the local is a move. This will cause constant values to be propagated to the returned local
      Returns:
      null-ok; the salient register spec or null if no local target was set since the last time clearArgs() was called

    • clearResult

      protected final void clearResult()
      Clears the results.

    • setResult

      protected final void setResult(TypeBearer result)
      Sets the results list to be the given single value.

      Note: If there is more than one result value, the others may be added by using addResult(TypeBearer).

      Parameters:
      result - non-null; result value

    • addResult

      protected final void addResult(TypeBearer result)
      Adds an additional element to the list of results.
      Parameters:
      result - non-null; result value
      See Also:

    • resultCount

      protected final int resultCount()
      Gets the count of results. This throws an exception if results were never set. (Explicitly clearing the results counts as setting them.)
      Returns:
      >= 0; the count

    • resultWidth

      protected final int resultWidth()
      Gets the width of the results (where a category-2 value counts as two).
      Returns:
      >= 0; the result width

    • result

      protected final TypeBearer result(int n)
      Gets the nth result value.
      Parameters:
      n - >= 0, < resultCount(); which result
      Returns:
      non-null; the indicated result value

    • storeResults

      protected final void storeResults(Frame frame)
      Stores the results of the latest operation into the given frame. If there is a local target (see localTarget), then the sole result is stored to that target; otherwise any results are pushed onto the stack.
      Parameters:
      frame - non-null; frame to operate on

    • throwLocalMismatch

      public static void throwLocalMismatch(TypeBearer found, TypeBearer local)
      Throws an exception that indicates a mismatch in local variable types.
      Parameters:
      found - non-null; the encountered type
      local - non-null; the local variable's claimed type