treenode.java

用Java实现的编译器。把源代码编译成SPARC汇编程序

// $Id: TreeNode.java,v 1.5 1999/09/27 20:01:29 deberg Exp $

package java6035.tools.IR;

/**
 * TreeNode 
 *
 * is the basic building block of IR trees. Subclasses of the TreeNode class
 * represent constructs in programming languages. The default subclasses
 * available in this package are:
 *
 * <PRE>
 * if-else              TreeIf class
 * instructions         Instruction class
 * while loops          TreeWhile class
 * blocks               TreeBlock class
 * </PRE>
 */

public abstract class TreeNode extends IRObject implements Walkable
{
    protected static final int SIMPLE_INSTR = 0;
    protected static final int BRANCH_INSTR = 1;
    protected static final int LABEL_INSTR  = 2;
    protected static final int RETURN_INSTR = 3;
    protected static final int TREE_IF    = 4;
    protected static final int TREE_WHILE = 5;
    protected static final int TREE_BLOCK = 6;
    protected static final int TREE_PROC  = 7;

    private TreeNode parent;

    protected abstract int tnkind();
   
    /**
     * Returns true if the node is a simple instruction. False
     * otherwise 
     */
    public boolean isSimpleInstr()
    {
	return tnkind() == SIMPLE_INSTR;
    }

    /**
     * Returns true if the node is a branch instruction. False
     * otherwise 
     */
    public boolean isBranchInstr()
    {
	return tnkind() == BRANCH_INSTR;
    }

    /**
     * Returns true if the node is a label instruction. False
     * otherwise 
     */
    public boolean isLabelInstr()
    {
	return tnkind() == LABEL_INSTR;
    }

    /**
     * Returns true if the node is a return instruction. False
     * otherwise 
     */
    public boolean isReturnInstr()
    {
	return tnkind() == RETURN_INSTR;
    }

    /**
     * Returns true if the node is a while node. False otherwise.
     */
    public boolean isTreeWhile()
    {
	return tnkind() == TREE_WHILE;
    }

    /**
     * Returns true if the node is an if node. False otherwise.
     */
    public boolean isTreeIf()
    {
	return tnkind() == TREE_IF;
    }

    /**
     * Returns true if the node is a block node. False otherwise.
     */
    public boolean isTreeBlock()
    {
	return tnkind() == TREE_BLOCK;
    }

    /**
     * Returns true if the node is a procedure node. False otherwise.
     */
    public boolean isTreeProc()
    {
	return tnkind() == TREE_PROC;
    }

    /**
     * Returns parent TreeNode
     */
    public TreeNode getParent()
    {
	return parent;
    }

    /**
     * Sets parent TreeNode
     */
    public void setParent(TreeNode parent)
    {
        this.parent = parent;
    }

    /**
     * Searches for annotation, given an annotation tag.  Returns
     * the object if found, otherwise looks in parent, etc...
     */
    public Object getHierAnnotation(int tag)
    {
	Object x = annotations.get(new Integer(tag));
        if (x != null)
            return x;
        else
            if (parent != null)
                return parent.getHierAnnotation(tag);
            else
                return null;
    }

}