Package org.codehaus.groovy.classgen.asm

Class CompileStack

  • All Implemented Interfaces:
    org.objectweb.asm.Opcodes
    public class CompileStack
extends Object
implements org.objectweb.asm.Opcodes
    This class is a helper for AsmClassGenerator. It 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

    • Method Detail

      • pushState

        public void pushState()

      • getContinueLabel

        public org.objectweb.asm.Label getContinueLabel()

      • getBreakLabel

        public org.objectweb.asm.Label getBreakLabel()

      • removeVar

        public void removeVar​(int tempIndex)

      • pop

        public void pop()

      • defineTemporaryVariable

        public int defineTemporaryVariable​(Variable var,
                                   boolean store)
        creates a temporary variable.
        Parameters:
        var - defines type and name
        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,
                                    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 el,
                 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 el)
        Causes the state-stack to add an element and sets the given scope as new current variable scope. Creates a element for the state stack so pop has to be called later

      • pushLoop

        public void pushLoop​(VariableScope el,
                     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 a 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 a 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 a 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.

      • 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()

      • isLHS

        public boolean isLHS()

      • pushLHS

        public void pushLHS​(boolean lhs)

      • popLHS

        public void popLHS()

      • pushImplicitThis

        public void pushImplicitThis​(boolean implicitThis)

      • isImplicitThis

        public boolean isImplicitThis()

      • popImplicitThis

        public void popImplicitThis()

      • isInSpecialConstructorCall

        public boolean isInSpecialConstructorCall()

      • pushInSpecialConstructorCall

        public void pushInSpecialConstructorCall()