Package org.codehaus.groovy.classgen.asm

# Class CompileStack

java.lang.Object
org.codehaus.groovy.classgen.asm.CompileStack

public class CompileStack extends Object
Manages different aspects of the code of a code block like handling labels, defining variables, and scopes. After a MethodNode is visited clear should be called, for initialization the method init should be used.

Some Notes:

- every push method will require a later pop call
- method parameters may define a category 2 variable, so don't ignore the type stored in the variable object
- the index of the variable may not be as assumed when the variable is a parameter of a method because the parameter may be used in a closure, so don't ignore the stored variable index
- the names of temporary variables can be ignored. The names are only used for debugging and do not conflict with each other or normal variables. For accessing, the index of the variable must be used.
- never mix temporary and normal variables by changes to this class. While the name is very important for a normal variable, it is only a helper construct for temporary variables. That means for example a name for a temporary variable can be used multiple times without conflict. So mixing them both may lead to the problem that a normal or temporary variable is hidden or even removed. That must not happen!

See Also:
  - `AsmClassGenerator`

- ## Nested Class Summary

  Nested Classes
  Modifier and Type
  Class
  Description
  `static class`
  `CompileStack.BlockRecorder`
  `protected static class`
  `CompileStack.LabelRange`

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `CompileStack(WriterController controller)`

- ## Method Summary

  Modifier and Type
  Method
  Description
  `void`
  `addExceptionBlock(org.objectweb.asm.Label start, org.objectweb.asm.Label end, org.objectweb.asm.Label goal, String sig)`
  `void`
  `applyBlockRecorder()`
  `void`
  `applyFinallyBlocks(org.objectweb.asm.Label label, boolean isBreakLabel)`
  `void`
  `clear()`
  Clears the state of the class.
  `boolean`
  `containsVariable(String name)`
  `org.objectweb.asm.Label`
  `createLocalLabel(String name)`
  creates a new named label
  `int`
  `defineTemporaryVariable(String name, boolean store)`
  creates a temporary variable.
  `int`
  `defineTemporaryVariable(String name, ClassNode node, boolean store)`
  creates a temporary variable.
  `int`
  `defineTemporaryVariable(Variable var, boolean store)`
  Creates a temporary variable.
  `BytecodeVariable`
  `defineVariable(Variable v, boolean initFromStack)`
  Defines a new Variable using an AST variable.
  `BytecodeVariable`
  `defineVariable(Variable v, ClassNode variableType, boolean initFromStack)`
  `org.objectweb.asm.Label`
  `getBreakLabel()`
  `org.objectweb.asm.Label`
  `getContinueLabel()`
  `org.objectweb.asm.Label`
  `getLabel(String name)`
  Returns the label for the given name
  `org.objectweb.asm.Label`
  `getNamedBreakLabel(String name)`
  Used for `break foo` inside a loop to end the execution of the marked loop.
  `org.objectweb.asm.Label`
  `getNamedContinueLabel(String name)`
  Used for `continue foo` inside a loop to continue the execution of the marked loop.
  `VariableScope`
  `getScope()`
  `BytecodeVariable`
  `getVariable(String variableName)`
  `BytecodeVariable`
  `getVariable(String variableName, boolean mustExist)`
  Returns a normal variable.
  `boolean`
  `hasBlockRecorder()`
  `void`
  `init(VariableScope scope, Parameter[] parameters)`
  initializes this class for a MethodNode.
  `boolean`
  `isImplicitThis()`
  `boolean`
  `isInSpecialConstructorCall()`
  `boolean`
  `isLHS()`
  `void`
  `pop()`
  `void`
  `popBlockRecorderVisit(CompileStack.BlockRecorder finallyBlock)`
  `void`
  `popImplicitThis()`
  `void`
  `popLHS()`
  `void`
  `pushBlockRecorder(CompileStack.BlockRecorder recorder)`
  `void`
  `pushBlockRecorderVisit(CompileStack.BlockRecorder finallyBlock)`
  `void`
  `pushBooleanExpression()`
  because a boolean Expression may not be evaluated completely it is important to keep the registers clean
  `void`
  `pushImplicitThis(boolean implicitThis)`
  `void`
  `pushInSpecialConstructorCall()`
  `void`
  `pushLHS(boolean lhs)`
  `void`
  `pushLoop(String labelName)`
  Should be called when descending into a loop that does not define a scope.
  `void`
  `pushLoop(List<String> labelNames)`
  Should be called when descending into a loop that does not define a scope.
  `void`
  `pushLoop(VariableScope scope, String labelName)`
  Should be called when descending into a loop that defines also a scope.
  `void`
  `pushLoop(VariableScope el, List<String> labelNames)`
  Should be called when descending into a loop that defines also a scope.
  `void`
  `pushState()`
  `org.objectweb.asm.Label`
  `pushSwitch()`
  Creates a new break label and an element for the state stack so pop has to be called later
  `void`
  `pushVariableScope(VariableScope scope)`
  Causes the state-stack to add an element and sets the given scope as new current variable scope.
  `void`
  `removeVar(int variableIndex)`
  Indicates that the specified temporary variable is no longer used.
  `void`
  `writeExceptionTable(CompileStack.BlockRecorder block, org.objectweb.asm.Label goal, String sig)`

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

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

- ## Constructor Details

  - ### CompileStack

    public CompileStack(WriterController controller)

- ## Method Details

  - ### getBreakLabel

    public org.objectweb.asm.Label getBreakLabel()

  - ### getContinueLabel

    public org.objectweb.asm.Label getContinueLabel()

  - ### getScope

    public VariableScope getScope()

  - ### pushState

    public void pushState()

  - ### removeVar

    public void removeVar(int variableIndex)
    Indicates that the specified temporary variable is no longer used.

  - ### pop

    public void pop()

  - ### defineTemporaryVariable

    public int defineTemporaryVariable(Variable var, boolean store)
    Creates a temporary variable.
    Parameters:
      `var` - specifies name and type
      `store` - defines if the toplevel argument of the stack should be stored
    Returns:
      the index used for this temporary variable

  - ### getVariable

    public BytecodeVariable getVariable(String variableName)

  - ### getVariable

    public BytecodeVariable getVariable(String variableName, boolean mustExist)
    Returns a normal variable.

    If `mustExist` is true and the normal variable doesn't exist, then this method will throw a GroovyBugError. It is not the intention of this method to let this happen! And the exception should not be used for flow control - it is just acting as an assertion. If the exception is thrown then it indicates a bug in the class using CompileStack. This method can also not be used to return a temporary variable. Temporary variables are not normal variables.

    Parameters:
      `variableName` - name of the variable
      `mustExist` - throw exception if variable does not exist
    Returns:
      the normal variable or null if not found (and `mustExist` not true)

  - ### defineTemporaryVariable

    public int defineTemporaryVariable(String name, boolean store)
    creates a temporary variable.
    Parameters:
      `name` - defines type and name
      `store` - defines if the top-level argument of the stack should be stored
    Returns:
      the index used for this temporary variable

  - ### defineTemporaryVariable

    public int defineTemporaryVariable(String name, ClassNode node, boolean store)
    creates a temporary variable.
    Parameters:
      `name` - defines the name
      `node` - defines the node
      `store` - defines if the top-level argument of the stack should be stored
    Returns:
      the index used for this temporary variable

  - ### clear

    public void clear()
    Clears the state of the class. This method should be called after a MethodNode is visited. Note that a call to init will fail if clear is not called before

  - ### addExceptionBlock

    public void addExceptionBlock(org.objectweb.asm.Label start, org.objectweb.asm.Label end, org.objectweb.asm.Label goal, String sig)

  - ### init

    public void init(VariableScope scope, Parameter[] parameters)
    initializes this class for a MethodNode. This method will automatically define variables for the method parameters and will create references if needed. The created variables can be accessed by calling getVariable().

  - ### pushVariableScope

    public void pushVariableScope(VariableScope scope)
    Causes the state-stack to add an element and sets the given scope as new current variable scope. Creates an element for the state stack so pop has to be called later

  - ### pushLoop

    public void pushLoop(VariableScope scope, String labelName)
    Should be called when descending into a loop that defines also a scope. Calls pushVariableScope and prepares labels for a loop structure. Creates a element for the state stack so pop has to be called later, TODO: @Deprecate

  - ### pushLoop

    public void pushLoop(VariableScope el, List<String> labelNames)
    Should be called when descending into a loop that defines also a scope. Calls pushVariableScope and prepares labels for a loop structure. Creates an element for the state stack so pop has to be called later

  - ### pushLoop

    public void pushLoop(String labelName)
    Should be called when descending into a loop that does not define a scope. Creates a element for the state stack so pop has to be called later, TODO: @Deprecate

  - ### pushLoop

    public void pushLoop(List<String> labelNames)
    Should be called when descending into a loop that does not define a scope. Creates an element for the state stack so pop has to be called later

  - ### getNamedBreakLabel

    public org.objectweb.asm.Label getNamedBreakLabel(String name)
    Used for `break foo` inside a loop to end the execution of the marked loop. This method will return the break label of the loop if there is one found for the name. If not, the current break label is returned.

  - ### getNamedContinueLabel

    public org.objectweb.asm.Label getNamedContinueLabel(String name)
    Used for `continue foo` inside a loop to continue the execution of the marked loop. This method will return the break label of the loop if there is one found for the name. If not, getLabel is used.

  - ### pushSwitch

    public org.objectweb.asm.Label pushSwitch()
    Creates a new break label and an element for the state stack so pop has to be called later

  - ### pushBooleanExpression

    public void pushBooleanExpression()
    because a boolean Expression may not be evaluated completely it is important to keep the registers clean

  - ### defineVariable

    public BytecodeVariable defineVariable(Variable v, boolean initFromStack)
    Defines a new Variable using an AST variable.
    Parameters:
      `initFromStack` - if true the last element of the stack will be used to initialize the new variable. If false null will be used.

  - ### defineVariable

    public BytecodeVariable defineVariable(Variable v, ClassNode variableType, boolean initFromStack)

  - ### containsVariable

    public boolean containsVariable(String name)
    Parameters:
      `name` - the name of the variable of interest
    Returns:
      true if a variable is already defined

  - ### getLabel

    public org.objectweb.asm.Label getLabel(String name)
    Returns the label for the given name

  - ### createLocalLabel

    public org.objectweb.asm.Label createLocalLabel(String name)
    creates a new named label

  - ### applyFinallyBlocks

    public void applyFinallyBlocks(org.objectweb.asm.Label label, boolean isBreakLabel)

  - ### applyBlockRecorder

    public void applyBlockRecorder()

  - ### hasBlockRecorder

    public boolean hasBlockRecorder()

  - ### pushBlockRecorder

    public void pushBlockRecorder(CompileStack.BlockRecorder recorder)

  - ### pushBlockRecorderVisit

    public void pushBlockRecorderVisit(CompileStack.BlockRecorder finallyBlock)

  - ### popBlockRecorderVisit

    public void popBlockRecorderVisit(CompileStack.BlockRecorder finallyBlock)

  - ### writeExceptionTable

    public void writeExceptionTable(CompileStack.BlockRecorder block, org.objectweb.asm.Label goal, String sig)

  - ### isLHS

    public boolean isLHS()

  - ### pushLHS

    public void pushLHS(boolean lhs)

  - ### popLHS

    public void popLHS()

  - ### isImplicitThis

    public boolean isImplicitThis()

  - ### pushImplicitThis

    public void pushImplicitThis(boolean implicitThis)

  - ### popImplicitThis

    public void popImplicitThis()

  - ### isInSpecialConstructorCall

    public boolean isInSpecialConstructorCall()

  - ### pushInSpecialConstructorCall

    public void pushInSpecialConstructorCall()