1 cananian 1.1.2.1 // BackendDerivation.java, created Tue Feb 29 12:03:41 2000 by cananian
2 cananian 1.1.2.1 // Copyright (C) 1999 C. Scott Ananian <cananian@alumni.princeton.edu>
3 cananian 1.1.2.1 // Licensed under the terms of the GNU GPL; see COPYING for details.
4 cananian 1.1.2.1 package harpoon.Backend.Maps;
5 cananian 1.1.2.1
6 cananian 1.1.2.1 import harpoon.ClassFile.HCodeElement;
7 cananian 1.1.2.1 import harpoon.Temp.Temp;
8 cananian 1.1.2.1 /**
9 cananian 1.1.2.1 * <code>BackendDerivation</code> provides, in addition to the type and
10 cananian 1.1.2.1 * derivation information provided by <code>Analysis.Maps.Derivation</code>,
11 cananian 1.1.2.1 * a means to identify (polymorphically typed) callee-save registers.
12 cananian 1.1.2.1 * <p>
13 cananian 1.1.2.1 * Note that <code>BackendDerivation</code> extends <code>Derivation</code>,
14 cananian 1.1.2.1 * so non-callee-save-register values will continue to have class and
15 cananian 1.1.2.1 * derivation types. The <code>typeMap()</code> and <code>derivation()</code>
16 cananian 1.1.2.1 * functions should both return <code>null</code> if the temporary in
17 cananian 1.1.2.1 * question is holding a callee-save register value.
18 cananian 1.1.2.1 *
19 cananian 1.1.2.1 * @author C. Scott Ananian <cananian@alumni.princeton.edu>
20 cananian 1.2 * @version $Id: BackendDerivation.java,v 1.2 2002/02/25 21:01:55 cananian Exp $
21 cananian 1.1.2.1 */
22 cananian 1.1.2.1 public interface BackendDerivation extends harpoon.Analysis.Maps.Derivation {
23 cananian 1.1.2.1
24 cananian 1.1.2.1 /** Map compiler temporaries to the callee-save register location
25 cananian 1.1.2.1 * they correspond to.
26 cananian 1.1.2.1 * @param t The temporary to query.
27 cananian 1.1.2.1 * @param hce A definition point for <code>t</code>.
28 cananian 1.1.2.1 * @return <code>null</code> if the temporary does not hold the
29 cananian 1.1.2.1 * value of a callee-save register, or else the identity
30 cananian 1.1.2.1 * of the callee-save register.
31 cananian 1.1.2.1 * @exception NullPointerException if <code>t</code> or <code>hc</code>
32 cananian 1.1.2.1 * is <code>null</code>.
33 cananian 1.1.2.1 * @exception TypeNotKnownException if the <code>BackendDerivation</code>
34 cananian 1.1.2.1 * has no information about <code>t</code> as defined
35 cananian 1.1.2.1 * at <code>hce</code>.
36 cananian 1.1.2.1 */
37 cananian 1.1.2.1 public Register calleeSaveRegister(HCodeElement hce, Temp t);
38 cananian 1.1.2.1
39 cananian 1.1.2.1 public static interface Register {
40 cananian 1.1.2.1 /** Returns the index of this register in the machine register file.
41 cananian 1.1.2.1 * This index is zero based and dense; it may not map directly
42 cananian 1.1.2.1 * to this register's position in the register file. For example,
43 cananian 1.1.2.1 * the first usable/local register in the register file will have
44 cananian 1.1.2.1 * index 0, even if it is logically designated, say, "r8". The
45 cananian 1.1.2.1 * register indexes returned here must be consistent with those
46 cananian 1.1.2.1 * returned by
47 cananian 1.1.2.1 * <code>Backend.Generic.RegFileInfo.MachineRegLoc</code>.
48 cananian 1.1.2.1 */
49 cananian 1.1.2.1 public int regIndex();
50 cananian 1.1.2.1 }
51 cananian 1.2 }