/*
* Copyright (C) 2007 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.dx.rop.code;
import com.android.dx.rop.cst.Constant;
import com.android.dx.rop.cst.CstUtf8;
import com.android.dx.rop.type.Type;
import com.android.dx.rop.type.TypeBearer;
import com.android.dx.util.ToHuman;
import java.util.HashMap;
/**
* Combination of a register number and a type, used as the sources and
* destinations of register-based operations.
*/
public final class RegisterSpec
implements TypeBearer, ToHuman, Comparable<RegisterSpec> {
/** non-null; string to prefix register numbers with */
public static final String PREFIX = "v";
/** non-null; intern table for instances */
private static final HashMap<Object, RegisterSpec> theInterns =
new HashMap<Object, RegisterSpec>(1000);
/** non-null; common comparison instance used while interning */
private static final ForComparison theInterningItem = new ForComparison();
/** >= 0; register number */
private final int reg;
/** non-null; type loaded or stored */
private final TypeBearer type;
/** null-ok; local variable info associated with this register, if any */
private final LocalItem local;
/**
* Intern the given triple as an instance of this class.
*
* @param reg >= 0; the register number
* @param type non-null; the type (or possibly actual value) which
* is loaded from or stored to the indicated register
* @param local null-ok; the associated local variable, if any
* @return non-null; an appropriately-constructed instance
*/
private static RegisterSpec intern(int reg, TypeBearer type,
LocalItem local) {
theInterningItem.set(reg, type, local);
RegisterSpec found = theInterns.get(theInterningItem);
if (found != null) {
return found;
}
found = theInterningItem.toRegisterSpec();
theInterns.put(found, found);
return found;
}
/**
* Returns an instance for the given register number and type, with
* no variable info. This method is allowed to return shared
* instances (but doesn't necessarily do so).
*
* @param reg >= 0; the register number
* @param type non-null; the type (or possibly actual value) which
* is loaded from or stored to the indicated register
* @return non-null; an appropriately-constructed instance
*/
public static RegisterSpec make(int reg, TypeBearer type) {
return intern(reg, type, null);
}
/**
* Returns an instance for the given register number, type, and
* variable info. This method is allowed to return shared
* instances (but doesn't necessarily do so).
*
* @param reg >= 0; the register number
* @param type non-null; the type (or possibly actual value) which
* is loaded from or stored to the indicated register
* @param local non-null; the associated local variable
* @return non-null; an appropriately-constructed instance
*/
public static RegisterSpec make(int reg, TypeBearer type,
LocalItem local) {
if (local == null) {
throw new NullPointerException("local == null");
}
return intern(reg, type, local);
}
/**
* Returns an instance for the given register number, type, and
* variable info. This method is allowed to return shared
* instances (but doesn't necessarily do so).
*
* @param reg >= 0; the register number
* @param type non-null; the type (or possibly actual value) which
* is loaded from or stored to the indicated register
* @param local null-ok; the associated variable info or null for
* none
* @return non-null; an appropriately-constructed instance
*/
public static RegisterSpec makeLocalOptional(
int reg, TypeBearer type, LocalItem local) {
return intern(reg, type, local);
}
/**
* Gets the string form for the given register number.
*
* @param reg >= 0; the register number
* @return non-null; the string form
*/
public static String regString(int reg) {
return PREFIX + reg;
}
/**
* Constructs an instance. This constructor is private. Use
* {@link #make}.
*
* @param reg >= 0; the register number
* @param type non-null; the type (or possibly actual value) which
* is loaded from or stored to the indicated register
* @param local null-ok; the associated local variable, if any
*/
private RegisterSpec(int reg, TypeBearer type, LocalItem local) {
if (reg < 0) {
throw new IllegalArgumentException("reg < 0");
}
if (type == null) {
throw new NullPointerException("type == null");
}
this.reg = reg;
this.type = type;
this.local = local;
}
/** {@inheritDoc} */
@Override
public boolean equals(Object other) {
if (!(other instanceof RegisterSpec)) {
if (other instanceof ForComparison) {
ForComparison fc = (ForComparison) other;
return equals(fc.reg, fc.type, fc.local);
}
return false;
}
RegisterSpec spec = (RegisterSpec) other;
return equals(spec.reg, spec.type, spec.local);
}
/**
* Like {@code equals}, but only consider the simple types of the
* registers. That is, this compares {@code getType()} on the types
* to ignore whatever arbitrary extra stuff might be carried around
* by an outer {@link TypeBearer}.
*
* @param other null-ok; spec to compare to
* @return {@code true} iff {@code this} and {@code other} are equal
* in the stated way
*/
public boolean equalsUsingSimpleType(RegisterSpec other) {
if (!matchesVariable(other)) {
return false;
}
return (reg == other.reg);
}
/**
* Like {@link #equalsUsingSimpleType} but ignoring the register number.
* This is useful to determine if two instances refer to the "same"
* local variable.
*
* @param other null-ok; spec to compare to
* @return {@code true} iff {@code this} and {@code other} are equal
* in the stated way
*/
public boolean matchesVariable(RegisterSpec other) {
if (other == null) {
return false;
}
return type.getType().equals(other.type.getType())
&& ((local == other.local)
|| ((local != null) && local.equals(other.local)));
}
/**
* Helper for {@link #equals} and {@link #ForComparison.equals},
* which actually does the test.
*
* @param reg value of the instance variable, for another instance
* @param type value of the instance variable, for another instance
* @param local value of the instance variable, for another instance
* @return whether this instance is equal to one with the given
* values
*/
private boolean equals(int reg, TypeBearer type, LocalItem local) {
return (this.reg == reg)
&& this.type.equals(type)
&& ((this.local == local)
|| ((this.local != null) && this.local.equals(local)));
}
/**
* Compares by (in priority order) register number, unwrapped type
* (that is types not {@link TypeBearer}s, and local info.
*
* @param other non-null; spec to compare to
* @return {@code -1..1}; standard result of comparison
*/
public int compareTo(RegisterSpec other) {
if (this.reg < other.reg) {
return -1;
} else if (this.reg > other.reg) {
return 1;
}
int compare = type.getType().compareTo(other.type.getType());
if (compare != 0) {
return compare;
}
if (this.local == null) {
return (other.local == null) ? 0 : -1;
} else if (other.local == null) {
return 1;
}
return this.local.compareTo(other.local);
}
/** {@inheritDoc} */
@Override
public int hashCode() {
return hashCodeOf(reg, type, local);
}
/**
* Helper for {@link #hashCode} and {@link #ForComparison.hashCode},
* which actually does the calculation.
*
* @param reg value of the instance variable
* @param type value of the instance variable
* @param local value of the instance variable
* @return the hash code
*/
private static int hashCodeOf(int reg, TypeBearer type, LocalItem local) {
int hash = (local != null) ? local.hashCode() : 0;
hash = (hash * 31 + type.hashCode()) * 31 + reg;
return hash;
}
/** {@inheritDoc} */
@Override
public String toString() {
return toString0(false);
}
/** {@inheritDoc} */
public String toHuman() {
return toString0(true);
}
/** {@inheritDoc} */
public Type getType() {
return type.getType();
}
/** {@inheritDoc} */
public TypeBearer getFrameType() {
return type.getFrameType();
}
/** {@inheritDoc} */
public final int getBasicType() {
return type.getBasicType();
}
/** {@inheritDoc} */
public final int getBasicFrameType() {
return type.getBasicFrameType();
}
/** {@inheritDoc} */
public final boolean isConstant() {
return false;
}
/**
* Gets the register number.
*
* @return >= 0; the register number
*/
public int getReg() {
return reg;
}
/**
* Gets the type (or actual value) which is loaded from or stored
* to the register associated with this instance.
*
* @return non-null; the type
*/
public TypeBearer getTypeBearer() {
return type;
}
/**
* Gets the variable info associated with this instance, if any.
*
* @return null-ok; the variable info, or <code>null</code> if this
* instance has none
*/
public LocalItem getLocalItem() {
return local;
}
/**
* Gets the next available register number after the one in this
* instance. This is equal to the register number plus the width
* (category) of the type used. Among other things, this may also
* be used to determine the minimum required register count
* implied by this instance.
*
* @return >= 0; the required registers size
*/
public int getNextReg() {
return reg + getCategory();
}
/**
* Gets the category of this instance's type. This is just a convenient
* shorthand for <code>getType().getCategory()</code>.
*
* @see #isCategory1
* @see #isCategory2
* @return 1..2; the category of this instance's type
*/
public int getCategory() {
return type.getType().getCategory();
}
/**
* Gets whether this instance's type is category 1. This is just a
* convenient shorthand for <code>getType().isCategory1()</code>.
*
* @see #getCategory
* @see #isCategory2
* @return whether or not this instance's type is of category 1
*/
public boolean isCategory1() {
return type.getType().isCategory1();
}
/**
* Gets whether this instance's type is category 2. This is just a
* convenient shorthand for <code>getType().isCategory2()</code>.
*
* @see #getCategory
* @see #isCategory1
* @return whether or not this instance's type is of category 2
*/
public boolean isCategory2() {
return type.getType().isCategory2();
}
/**
* Gets the string form for just the register number of this instance.
*
* @return non-null; the register string form
*/
public String regString() {
return regString(reg);
}
/**
* Returns an instance that is the intersection between this instance
* and the given one, if any. The intersection is defined as follows:
*
* <ul>
* <li>If <code>other</code> is <code>null</code>, then the result
* is <code>null</code>.
* <li>If the register numbers don't match, then the intersection
* is <code>null</code>. Otherwise, the register number of the
* intersection is the same as the one in the two instances.</li>
* <li>If the types returned by <code>getType()</code> are not
* <code>equals()</code>, then the intersection is null.</li>
* <li>If the type bearers returned by <code>getTypeBearer()</code>
* are <code>equals()</code>, then the intersection's type bearer
* is the one from this instance. Otherwise, the intersection's
* type bearer is the <code>getType()</code> of this instance.</li>
* <li>If the locals are <code>equals()</code>, then the local info
* of the intersection is the local info of this instance. Otherwise,
* the local info of the intersection is <code>null</code>.</li>
* </ul>
*
* @param other null-ok; instance to intersect with (or <code>null</code>)
* @param localPrimary whether local variables are primary to the
* intersection; if <code>true</code>, then the only non-null
* results occur when registers being intersected have equal local
* infos (or both have <code>null</code> local infos)
* @return null-ok; the intersection
*/
public RegisterSpec intersect(RegisterSpec other, boolean localPrimary) {
if (this == other) {
// Easy out.
return this;
}
if ((other == null) || (reg != other.getReg())) {
return null;
}
LocalItem resultLocal =
((local == null) || !local.equals(other.getLocalItem()))
? null : local;
boolean sameName = (resultLocal == local);
if (localPrimary && !sameName) {
return null;
}
Type thisType = getType();
Type otherType = other.getType();
// Note: Types are always interned.
if (thisType != otherType) {
return null;
}
TypeBearer resultTypeBearer =
type.equals(other.getTypeBearer()) ? type : thisType;
if ((resultTypeBearer == type) && sameName) {
// It turns out that the intersection is "this" after all.
return this;
}
return (resultLocal == null) ? make(reg, resultTypeBearer) :
make(reg, resultTypeBearer, resultLocal);
}
/**
* Returns an instance that is identical to this one, except that the
* register number is replaced by the given one.
*
* @param newReg >= 0; the new register number
* @return non-null; an appropriately-constructed instance
*/
public RegisterSpec withReg(int newReg) {
if (reg == newReg) {
return this;
}
return makeLocalOptional(newReg, type, local);
}
/**
* Returns an instance that is identical to this one, except that
* the type is replaced by the given one.
*
* @param newType non-null; the new type
* @return non-null; an appropriately-constructed instance
*/
public RegisterSpec withType(TypeBearer newType) {
return makeLocalOptional(reg, newType, local);
}
/**
* Returns an instance that is identical to this one, except that the
* register number is offset by the given amount.
*
* @param delta the amount to offset the register number by
* @return non-null; an appropriately-constructed instance
*/
public RegisterSpec withOffset(int delta) {
if (delta == 0) {
return this;
}
return withReg(reg + delta);
}
/**
* Returns an instance that is identical to this one, except that
* the type bearer is replaced by the actual underlying type
* (thereby stripping off non-type information) with any
* initialization information stripped away as well.
*
* @return non-null; an appropriately-constructed instance
*/
public RegisterSpec withSimpleType() {
TypeBearer orig = type;
Type newType;
if (orig instanceof Type) {
newType = (Type) orig;
} else {
newType = orig.getType();
}
if (newType.isUninitialized()) {
newType = newType.getInitializedType();
}
if (newType == orig) {
return this;
}
return makeLocalOptional(reg, newType, local);
}
/**
* Returns an instance that is identical to this one except that the
* local variable is as specified in the parameter.
*
* @param local null-ok; the local item or null for none
* @return an appropriate instance
*/
public RegisterSpec withLocalItem(LocalItem local) {
if ((this.local== local)
|| ((this.local != null) && this.local.equals(local))) {
return this;
}
return makeLocalOptional(reg, type, local);
}
/**
* Helper for {@link #toString} and {@link #toHuman}.
*
* @param human whether to be human-oriented
* @return non-null; the string form
*/
private String toString0(boolean human) {
StringBuffer sb = new StringBuffer(40);
sb.append(regString());
sb.append(":");
if (local != null) {
sb.append(local.toString());
}
Type justType = type.getType();
sb.append(justType);
if (justType != type) {
sb.append("=");
if (human && (type instanceof Constant)) {
sb.append(((Constant) type).toHuman());
} else {
sb.append(type);
}
}
return sb.toString();
}
/**
* Holder of register spec data for the purposes of comparison (so that
* <code>RegisterSpec</code> itself can still keep <code>final</code>
* instance variables.
*/
private static class ForComparison {
/** >= 0; register number */
private int reg;
/** non-null; type loaded or stored */
private TypeBearer type;
/** null-ok; local variable associated with this register, if any */
private LocalItem local;
/**
* Set all the instance variables.
*
* @param reg >= 0; the register number
* @param type non-null; the type (or possibly actual value) which
* is loaded from or stored to the indicated register
* @param local null-ok; the associated local variable, if any
* @return non-null; an appropriately-constructed instance
*/
public void set(int reg, TypeBearer type, LocalItem local) {
this.reg = reg;
this.type = type;
this.local = local;
}
/**
* Construct a <code>RegisterSpec</code> of this instance's
* contents.
*
* @return non-null; an appropriately-constructed instance
*/
public RegisterSpec toRegisterSpec() {
return new RegisterSpec(reg, type, local);
}
/** {@inheritDoc} */
@Override
public boolean equals(Object other) {
if (!(other instanceof RegisterSpec)) {
return false;
}
RegisterSpec spec = (RegisterSpec) other;
return spec.equals(reg, type, local);
}
/** {@inheritDoc} */
@Override
public int hashCode() {
return hashCodeOf(reg, type, local);
}
}
}
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