--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/Compiler/src/com/sun/c1x/alloc/OperandPool.java	Wed Apr 27 11:43:22 2011 +0200
@@ -0,0 +1,268 @@
+/*
+ * Copyright (c) 2010, 2011, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package com.sun.c1x.alloc;
+
+import java.util.*;
+
+import com.sun.c1x.*;
+import com.sun.c1x.ir.*;
+import com.sun.cri.ci.*;
+
+/**
+ * An ordered, 0-based indexable pool of instruction operands for a method being compiled.
+ * The physical {@linkplain CiRegister registers} of the platform occupy the front of the
+ * pool (starting at index 0) followed by {@linkplain CiVariable variable} operands.
+ * The index of an operand in the pool is its {@linkplain #operandNumber(CiValue) operand number}.
+ *
+ * In the original HotSpot C1 source code, this pool corresponds to the
+ * "flat register file" mentioned in c1_LinearScan.cpp.
+ *
+ * @author Doug Simon
+ */
+public final class OperandPool {
+
+    public static final int INITIAL_VARIABLE_CAPACITY = 20;
+
+    /**
+     * The physical registers occupying the head of the operand pool. This is the complete
+     * {@linkplain CiArchitecture#registers register set} of the target architecture, not
+     * just the allocatable registers.
+     */
+    private final CiRegister[] registers;
+
+    /**
+     * The variable operands allocated from this pool. The {@linkplain #operandNumber(CiValue) number}
+     * of the first variable operand in this pool is one greater than the number of the last
+     * register operand in the pool.
+     */
+    private final ArrayList<CiVariable> variables;
+
+    /**
+     * Map from a {@linkplain CiVariable#index variable index} to the instruction whose result is stored in the denoted variable.
+     * This map is only populated and used if {@link C1XOptions#DetailedAsserts} is {@code true}.
+     */
+    private final ArrayList<Value> variableDefs;
+
+    /**
+     * The {@linkplain #operandNumber(CiValue) number} of the first variable operand
+     * {@linkplain #newVariable(CiKind) allocated} from this pool.
+     */
+    private final int firstVariableNumber;
+
+    /**
+     * Records which variable operands have the {@link VariableFlag#MustBeByteRegister} flag set.
+     */
+    private CiBitMap mustBeByteRegister;
+
+    /**
+     * Records which variable operands have the {@link VariableFlag#MustStartInMemory} flag set.
+     */
+    private CiBitMap mustStartInMemory;
+
+    /**
+     * Records which variable operands have the {@link VariableFlag#MustStayInMemory} flag set.
+     */
+    private CiBitMap mustStayInMemory;
+
+    /**
+     * Flags that can be set for {@linkplain CiValue#isVariable() variable} operands.
+     */
+    public enum VariableFlag {
+        /**
+         * Denotes a variable that needs to be assigned a memory location
+         * at the beginning, but may then be loaded in a register.
+         */
+        MustStartInMemory,
+
+        /**
+         * Denotes a variable that needs to be assigned a memory location
+         * at the beginning and never subsequently loaded in a register.
+         */
+        MustStayInMemory,
+
+        /**
+         * Denotes a variable that must be assigned to a byte-sized register.
+         */
+        MustBeByteRegister;
+
+        public static final VariableFlag[] VALUES = values();
+    }
+
+    private static CiBitMap set(CiBitMap map, CiVariable variable) {
+        if (map == null) {
+            int length = CiBitMap.roundUpLength(variable.index + 1);
+            map = new CiBitMap(length);
+        } else if (map.size() <= variable.index) {
+            int length = CiBitMap.roundUpLength(variable.index + 1);
+            map.grow(length);
+        }
+        map.set(variable.index);
+        return map;
+    }
+
+    private static boolean get(CiBitMap map, CiVariable variable) {
+        if (map == null || map.size() <= variable.index) {
+            return false;
+        }
+        return map.get(variable.index);
+    }
+
+    /**
+     * Creates a new operand pool.
+     *
+     * @param target description of the target architecture for a compilation
+     */
+    public OperandPool(CiTarget target) {
+        CiRegister[] registers = target.arch.registers;
+        this.firstVariableNumber = registers.length;
+        this.registers = registers;
+        variables = new ArrayList<CiVariable>(INITIAL_VARIABLE_CAPACITY);
+        variableDefs = C1XOptions.DetailedAsserts ? new ArrayList<Value>(INITIAL_VARIABLE_CAPACITY) : null;
+    }
+
+    /**
+     * Creates a new {@linkplain CiVariable variable} operand.
+     *
+     * @param kind the kind of the variable
+     * @return a new variable
+     */
+    public CiVariable newVariable(CiKind kind) {
+        return newVariable(kind, kind == CiKind.Boolean || kind == CiKind.Byte ? VariableFlag.MustBeByteRegister : null);
+    }
+
+    /**
+     * Creates a new {@linkplain CiVariable variable} operand.
+     *
+     * @param kind the kind of the variable
+     * @param flag a flag that is set for the new variable operand (ignored if {@code null})
+     * @return a new variable operand
+     */
+    public CiVariable newVariable(CiKind kind, VariableFlag flag) {
+        assert kind != CiKind.Void;
+        int varIndex = variables.size();
+        CiVariable var = CiVariable.get(kind, varIndex);
+        if (flag == VariableFlag.MustBeByteRegister) {
+            mustBeByteRegister = set(mustBeByteRegister, var);
+        } else if (flag == VariableFlag.MustStartInMemory) {
+            mustStartInMemory = set(mustStartInMemory, var);
+        } else if (flag == VariableFlag.MustStayInMemory) {
+            mustStayInMemory = set(mustStayInMemory, var);
+        } else {
+            assert flag == null;
+        }
+        variables.add(var);
+        return var;
+    }
+
+    /**
+     * Gets the unique number for an operand contained in this pool.
+     *
+     *
+     * @param operand an operand
+     * @return the unique number for {@code operand} in the range {@code [0 .. size())}
+     */
+    public int operandNumber(CiValue operand) {
+        if (operand.isRegister()) {
+            int number = operand.asRegister().number;
+            assert number < firstVariableNumber;
+            return number;
+        }
+        assert operand.isVariable();
+        return firstVariableNumber + ((CiVariable) operand).index;
+    }
+
+    /**
+     * Gets the operand in this pool denoted by a given operand number.
+     *
+     * @param operandNumber a value that must be in the range {@code [0 .. size())}
+     * @return the operand in this pool denoted by {@code operandNumber}
+     */
+    public CiValue operandFor(int operandNumber) {
+        if (operandNumber < firstVariableNumber) {
+            assert operandNumber >= 0;
+            return registers[operandNumber].asValue();
+        }
+        int index = operandNumber - firstVariableNumber;
+        CiVariable variable = variables.get(index);
+        assert variable.index == index;
+        return variable;
+    }
+
+    /**
+     * Records that the result of {@code instruction} is stored in {@code result}.
+     *
+     * @param result the variable storing the result of {@code instruction}
+     * @param instruction an instruction that produces a result (i.e. pushes a value to the stack)
+     */
+    public void recordResult(CiVariable result, Value instruction) {
+        while (variableDefs.size() <= result.index) {
+            variableDefs.add(null);
+        }
+        variableDefs.set(result.index, instruction);
+    }
+
+    /**
+     * Gets the instruction whose result is recorded in a given variable.
+     *
+     * @param result the variable storing the result of an instruction
+     * @return the instruction that stores its result in {@code result}
+     */
+    public Value instructionForResult(CiVariable result) {
+        if (variableDefs.size() > result.index) {
+            return variableDefs.get(result.index);
+        }
+        return null;
+    }
+
+    public boolean mustStartInMemory(CiVariable operand) {
+        return get(mustStartInMemory, operand) || get(mustStayInMemory, operand);
+    }
+
+    public boolean mustStayInMemory(CiVariable operand) {
+        return get(mustStayInMemory, operand);
+    }
+
+    public boolean mustBeByteRegister(CiValue operand) {
+        return get(mustBeByteRegister, (CiVariable) operand);
+    }
+
+    public void setMustBeByteRegister(CiVariable operand) {
+        mustBeByteRegister = set(mustBeByteRegister, operand);
+    }
+
+    /**
+     * Gets the number of operands in this pool. This value will increase by 1 for
+     * each new variable operand {@linkplain #newVariable(CiKind) allocated} from this pool.
+     */
+    public int size() {
+        return firstVariableNumber + variables.size();
+    }
+
+    /**
+     * Gets the highest operand number for a register operand in this pool. This value will
+     * never change for the lifetime of this pool.
+     */
+    public int maxRegisterNumber() {
+        return firstVariableNumber - 1;
+    }
+}