labelinstr.java

来自「用Java实现的编译器。把源代码编译成SPARC汇编程序」· Java 代码 · 共 88 行

// $Id: LabelInstr.java,v 1.5 1999/11/12 17:58:18 deberg Exp $

package java6035.tools.IR;

/**
 * The LabelInstr class captures a label, as a branch target.
 */

public class LabelInstr extends Instruction
{
    protected String label;

    /**
     * Creates a label instruction with the given suffix as the suffix of the
     * label.
     */
    public LabelInstr(String suffix)
    {
	label = LabelInstr.getUniqueLabel(suffix);
    }

    public void setLabel(String label)
    {
        this.label = label;
    }

    private static int counter = 0;

    /**
     * Returns a unique string label.
     */
    protected static String getUniqueLabel(String suffix)
    {
	counter++;
        return new String("_L"+(counter-1)+"_"+suffix);
    }

    /**
     * Returns the label for this label instruction.
     */
    public String getLabel()
    {
	return label;
    }

    /**
     * Returns the type of the instruction.
     */
    protected int tnkind()
    {
	return LABEL_INSTR;
    }

    /**
     * Walkable: returns the name of the node.
     */
    public String getNodeName()
    {
	return "label "+label;
    }

    /**
     * Walkable: returns 0.
     */
    public int getNeighborCount()
    {
	return 0;
    }

    /**
     * Walkable: returns null.
     */
    public Object getNeighbor(int index)
    {
	return null;
    }

    public String PPrint(int indent, boolean recursive)
    {
        String output = new String();
        for(int i=0;i<indent;i++) output += " ";
        output += "(label_instruction "+label+")\n";

        return output;
    }
}