--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/Compiler/src/com/sun/c1x/ir/Value.java	Wed Apr 27 11:43:22 2011 +0200
@@ -0,0 +1,407 @@
+/*
+ * Copyright (c) 2009, 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.ir;
+
+import static com.sun.c1x.ir.Value.Flag.*;
+
+import com.sun.c1x.*;
+import com.sun.c1x.debug.*;
+import com.sun.c1x.opt.*;
+import com.sun.cri.ci.*;
+import com.sun.cri.ri.*;
+
+/**
+ * This class represents a value within the HIR graph, including local variables, phis, and
+ * all other instructions.
+ *
+ * @author Ben L. Titzer
+ */
+public abstract class Value {
+    /**
+     * An enumeration of flags on values.
+     */
+    public enum Flag {
+        NonNull,            // this value is non-null
+
+        NoNullCheck,        // does not require null check
+        NoStoreCheck,       // does not require store check
+        NoBoundsCheck,      // does not require bounds check
+        NoZeroCheck,        // divide or modulus cannot cause exception
+
+        NoReadBarrier,      // does not require read barrier
+        NoWriteBarrier,     // does not require write barrier
+        NoDivSpecialCase,   // divide or modulus cannot be special case of MIN_INT / -1
+        DirectCompare,
+        IsLoaded,           // field or method is resolved and class is loaded and initialized
+        IsStatic,           // field or method access is static
+        IsSafepoint,        // branch is backward (safepoint)
+        IsStrictFP,
+        PreservesState,     // intrinsic preserves state
+        UnorderedIsTrue,
+        NeedsPatching,
+        LiveValue,          // live because value is used
+        LiveDeopt,          // live for deoptimization
+        LiveControl,        // live for control dependencies
+        LiveSideEffect,     // live for possible side-effects only
+        LiveStore,          // instruction is a store
+        PhiDead,            // phi is illegal because local is dead
+        PhiCannotSimplify,  // phi cannot be simplified
+        PhiVisited,         // phi has been visited during simplification
+
+        ResultIsUnique;     // the result of this instruction is guaranteed to be unique (e.g. a new object)
+
+        public final int mask = 1 << ordinal();
+    }
+
+    private static final int LIVE_FLAGS = Flag.LiveValue.mask |
+                                          Flag.LiveDeopt.mask |
+                                          Flag.LiveControl.mask |
+                                          Flag.LiveSideEffect.mask;
+    /**
+     * The kind of this value. This is {@link CiKind#Void} for instructions that produce no value.
+     * This kind is guaranteed to be a {@linkplain CiKind#stackKind() stack kind}.
+     */
+    public final CiKind kind;
+
+    /**
+     * Unique identifier for this value. This field's value is lazily initialized by {@link #id()}.
+     */
+    private int id;
+
+    /**
+     * A mask of {@linkplain Flag flags} denoting extra properties of this value.
+     */
+    private int flags;
+
+    protected CiValue operand = CiValue.IllegalValue;
+
+    /**
+     * A cache for analysis information. Every optimization must reset this field to {@code null} once it has completed.
+     */
+    public Object optInfo;
+
+    /**
+     * Used by {@link InstructionSubstituter}.
+     */
+    public Value subst;
+
+    public abstract BlockBegin block();
+
+    /**
+     * Creates a new value with the specified kind.
+     * @param kind the type of this value
+     */
+    public Value(CiKind kind) {
+        assert kind == kind.stackKind() : kind + " != " + kind.stackKind();
+        this.kind = kind;
+    }
+
+    /**
+     * Checks whether this instruction is live (i.e. code should be generated for it).
+     * This is computed in a dedicated pass by {@link LivenessMarker}.
+     * An instruction is live because its value is needed by another live instruction,
+     * because its value is needed for deoptimization, or the program is control dependent
+     * upon it.
+     * @return {@code true} if this instruction should be considered live
+     */
+    public final boolean isLive() {
+        return C1XOptions.PinAllInstructions || (flags & LIVE_FLAGS) != 0;
+    }
+
+    /**
+     * Clears all liveness flags.
+     */
+    public final void clearLive() {
+        flags = flags & ~LIVE_FLAGS;
+    }
+
+    /**
+     * Gets the instruction that should be substituted for this one. Note that this
+     * method is recursive; if the substituted instruction has a substitution, then
+     * the final substituted instruction will be returned. If there is no substitution
+     * for this instruction, {@code this} will be returned.
+     * @return the substitution for this instruction
+     */
+    public final Value subst() {
+        if (subst == null) {
+            return this;
+        }
+        return subst.subst();
+    }
+
+    /**
+     * Checks whether this instruction has a substitute.
+     * @return {@code true} if this instruction has a substitution.
+     */
+    public final boolean hasSubst() {
+        return subst != null;
+    }
+
+    /**
+     * Eliminates a given runtime check for this instruction.
+     *
+     * @param flag the flag representing the (elimination of the) runtime check
+     */
+    public final void clearRuntimeCheck(Flag flag) {
+        if (!checkFlag(flag)) {
+            setFlag(flag);
+            runtimeCheckCleared();
+            if (flag == NoNullCheck) {
+                C1XMetrics.NullCheckEliminations++;
+            } else if (flag == NoBoundsCheck) {
+                C1XMetrics.BoundsChecksElminations++;
+            } else if (flag == NoStoreCheck) {
+                C1XMetrics.StoreCheckEliminations++;
+            } else if (flag != NoZeroCheck) {
+                throw new InternalError("Unknown runtime check: " + flag);
+            }
+        }
+    }
+
+
+    /**
+     * Clear any internal state related to null checks, because a null check
+     * for this instruction is redundant. The state cleared may depend
+     * on the type of this instruction
+     */
+    public final void eliminateNullCheck() {
+        clearRuntimeCheck(NoNullCheck);
+    }
+
+    /**
+     * Notifies this instruction that a runtime check has been
+     * eliminated or made redundant.
+     */
+    protected void runtimeCheckCleared() {
+    }
+
+    /**
+     * Check whether this instruction has the specified flag set.
+     * @param flag the flag to test
+     * @return {@code true} if this instruction has the flag
+     */
+    public final boolean checkFlag(Flag flag) {
+        return (flags & flag.mask) != 0;
+    }
+
+    /**
+     * Set a flag on this instruction.
+     * @param flag the flag to set
+     */
+    public final void setFlag(Flag flag) {
+        flags |= flag.mask;
+    }
+
+    /**
+     * Clear a flag on this instruction.
+     * @param flag the flag to set
+     */
+    public final void clearFlag(Flag flag) {
+        flags &= ~flag.mask;
+    }
+
+    /**
+     * Set or clear a flag on this instruction.
+     * @param flag the flag to set
+     * @param val if {@code true}, set the flag, otherwise clear it
+     */
+    public final void setFlag(Flag flag, boolean val) {
+        if (val) {
+            setFlag(flag);
+        } else {
+            clearFlag(flag);
+        }
+    }
+
+    /**
+     * Initialize a flag on this instruction. Assumes the flag is not initially set,
+     * e.g. in the constructor of an instruction.
+     * @param flag the flag to set
+     * @param val if {@code true}, set the flag, otherwise do nothing
+     */
+    public final void initFlag(Flag flag, boolean val) {
+        if (val) {
+            setFlag(flag);
+        }
+    }
+
+    /**
+     * Checks whether this instruction produces a value which is guaranteed to be non-null.
+     * @return {@code true} if this instruction's value is not null
+     */
+    public final boolean isNonNull() {
+        return checkFlag(Flag.NonNull);
+    }
+
+    /**
+     * Checks whether this instruction needs a null check.
+     * @return {@code true} if this instruction needs a null check
+     */
+    public final boolean needsNullCheck() {
+        return !checkFlag(Flag.NoNullCheck);
+    }
+
+    /**
+     * Checks whether this value is a constant (i.e. it is of type {@link Constant}.
+     * @return {@code true} if this value is a constant
+     */
+    public final boolean isConstant() {
+        return this instanceof Constant;
+    }
+
+    /**
+     * Checks whether this value represents the null constant.
+     * @return {@code true} if this value represents the null constant
+     */
+    public final boolean isNullConstant() {
+        return this instanceof Constant && ((Constant) this).value.isNull();
+    }
+
+    /**
+     * Checks whether this instruction "is illegal"--i.e. it represents a dead
+     * phi or an instruction which does not produce a value.
+     * @return {@code true} if this instruction is illegal as an input value to another instruction
+     */
+    public final boolean isIllegal() {
+        return checkFlag(Flag.PhiDead);
+    }
+
+    /**
+     * Convert this value to a constant if it is a constant, otherwise return null.
+     * @return the {@link CiConstant} represented by this value if it is a constant; {@code null}
+     * otherwise
+     */
+    public final CiConstant asConstant() {
+        if (this instanceof Constant) {
+            return ((Constant) this).value;
+        }
+        return null;
+    }
+
+    /**
+     * Gets the LIR operand associated with this instruction.
+     * @return the LIR operand for this instruction
+     */
+    public final CiValue operand() {
+        return operand;
+    }
+
+    /**
+     * Sets the LIR operand associated with this instruction.
+     * @param operand the operand to associate with this instruction
+     */
+    public final void setOperand(CiValue operand) {
+        assert this.operand.isIllegal() : "operand cannot be set twice";
+        assert operand != null && operand.isLegal() : "operand must be legal";
+        assert operand.kind.stackKind() == this.kind;
+        this.operand = operand;
+    }
+
+    /**
+     * Clears the LIR operand associated with this instruction.
+     */
+    public final void clearOperand() {
+        this.operand = CiValue.IllegalValue;
+    }
+
+    /**
+     * Computes the exact type of the result of this instruction, if possible.
+     * @return the exact type of the result of this instruction, if it is known; {@code null} otherwise
+     */
+    public RiType exactType() {
+        return null; // default: unknown exact type
+    }
+
+    /**
+     * Computes the declared type of the result of this instruction, if possible.
+     * @return the declared type of the result of this instruction, if it is known; {@code null} otherwise
+     */
+    public RiType declaredType() {
+        return null; // default: unknown declared type
+    }
+
+    /**
+     * Apply the specified closure to all the input values of this instruction.
+     * @param closure the closure to apply
+     */
+    public void inputValuesDo(ValueClosure closure) {
+        // default: do nothing.
+    }
+
+    @Override
+    public String toString() {
+        StringBuilder builder = new StringBuilder();
+        builder.append(getClass().getSimpleName());
+        builder.append(" #");
+        builder.append(id());
+        if (this instanceof Instruction) {
+            builder.append(" @ ");
+            builder.append(((Instruction) this).bci());
+        }
+        builder.append(" [").append(flagsToString()).append("]");
+        return builder.toString();
+    }
+
+    public String flagsToString() {
+        StringBuilder sb = new StringBuilder();
+        for (Flag f : Flag.values()) {
+            if (checkFlag(f)) {
+                if (sb.length() != 0) {
+                    sb.append(' ');
+                }
+                sb.append(f.name());
+            }
+        }
+        return sb.toString();
+    }
+
+    public final boolean isDeadPhi() {
+        return checkFlag(Flag.PhiDead);
+    }
+
+    /**
+     * This method supports the visitor pattern by accepting a visitor and calling the
+     * appropriate {@code visit()} method.
+     *
+     * @param v the visitor to accept
+     */
+    public abstract void accept(ValueVisitor v);
+
+    public abstract void print(LogStream out);
+
+    /**
+     * This method returns a unique identification number for this value. The number returned is unique
+     * only to the compilation that produced this node and is computed lazily by using the current compilation
+     * for the current thread. Thus the first access is a hash lookup using {@link java.lang.ThreadLocal} and
+     * should not be considered fast. Because of the potentially slow first access, use of this ID should be
+     * restricted to debugging output.
+     * @return a unique ID for this value
+     */
+    public int id() {
+        if (id == 0) {
+            C1XMetrics.UniqueValueIdsAssigned++;
+            id = C1XCompilation.compilation().nextID();
+        }
+        return id;
+    }
+}