001 /*
002 * This file is part of the Jikes RVM project (http://jikesrvm.org).
003 *
004 * This file is licensed to You under the Eclipse Public License (EPL);
005 * You may not use this file except in compliance with the License. You
006 * may obtain a copy of the License at
007 *
008 * http://www.opensource.org/licenses/eclipse-1.0.php
009 *
010 * See the COPYRIGHT.txt file distributed with this work for information
011 * regarding copyright ownership.
012 */
013 package org.jikesrvm.compilers.opt.regalloc;
014
015 import java.util.Enumeration;
016 import org.jikesrvm.ArchitectureSpecificOpt.PhysicalRegisterSet;
017 import org.jikesrvm.compilers.opt.ir.IR;
018 import org.jikesrvm.compilers.opt.ir.Register;
019
020 /**
021 * The register allocator currently caches a bunch of state in the IR;
022 * This class provides accessors to this state.
023 * <ul>
024 * <li>TODO: Consider caching the state in a lookaside structure.
025 * <li>TODO: Currently, the physical registers are STATIC! fix this.
026 * <ul>
027 */
028 public class RegisterAllocatorState {
029
030 /**
031 * Resets the physical register info
032 */
033 static void resetPhysicalRegisters(IR ir) {
034 PhysicalRegisterSet phys = ir.regpool.getPhysicalRegisterSet();
035 for (Enumeration<Register> e = phys.enumerateAll(); e.hasMoreElements();) {
036 Register reg = e.nextElement();
037 reg.deallocateRegister();
038 reg.mapsToRegister = null; // mapping from real to symbolic
039 // putPhysicalRegResurrectList(reg, null);
040 reg.defList = null;
041 reg.useList = null;
042 setSpill(reg, 0);
043 }
044 }
045
046 /**
047 * Special use of scratchObject field as "resurrect lists" for real registers
048 * TODO: use another field for safety; scratchObject is also used by
049 * clan LinearScanLiveAnalysis
050 */
051 /*
052 static void putPhysicalRegResurrectList(Register r,
053 LinearScanLiveInterval li) {
054 if (VM.VerifyAssertions) VM._assert(r.isPhysical());
055 r.scratchObject = li;
056 }
057 */
058 /**
059 *
060 * Special use of scratchObject field as "resurrect lists" for real registers
061 * TODO: use another field for safety; scratchObject is also used by
062 * clan LinearScanLiveAnalysis
063 */
064 /*
065 static LinearScanLiveInterval getPhysicalRegResurrectList(Register r) {
066 if (VM.VerifyAssertions) VM._assert(r.isPhysical());
067 return (LinearScanLiveInterval) r.scratchObject;
068 }
069 */
070 static void setSpill(Register reg, int spill) {
071 reg.spillRegister();
072 reg.scratch = spill;
073 }
074
075 public static int getSpill(Register reg) {
076 return reg.scratch;
077 }
078
079 /**
080 * Record that register A and register B are associated with each other
081 * in a bijection.<p>
082 *
083 * The register allocator uses this state to indicate that a symbolic
084 * register is presently allocated to a physical register.
085 */
086 static void mapOneToOne(Register A, Register B) {
087 Register aFriend = getMapping(A);
088 Register bFriend = getMapping(B);
089 if (aFriend != null) {
090 aFriend.mapsToRegister = null;
091 }
092 if (bFriend != null) {
093 bFriend.mapsToRegister = null;
094 }
095 A.mapsToRegister = B;
096 B.mapsToRegister = A;
097 }
098
099 /**
100 * @return the register currently mapped 1-to-1 to r
101 */
102 static Register getMapping(Register r) {
103 return r.mapsToRegister;
104 }
105
106 /**
107 * Clear any 1-to-1 mapping for register R.
108 */
109 static void clearOneToOne(Register r) {
110 if (r != null) {
111 Register s = getMapping(r);
112 if (s != null) {
113 s.mapsToRegister = null;
114 }
115 r.mapsToRegister = null;
116 }
117 }
118 }