/*
* 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.cf.code;
import com.android.dx.rop.code.RegisterSpec;
import com.android.dx.rop.code.LocalItem;
import com.android.dx.rop.cst.Constant;
import com.android.dx.rop.type.Prototype;
import com.android.dx.rop.type.StdTypeList;
import com.android.dx.rop.type.Type;
import com.android.dx.rop.type.TypeBearer;
import java.util.ArrayList;
/**
* Base implementation of {@link Machine}.
*
* <p><b>Note:</b> For the most part, the documentation for this class
* ignores the distinction between {@link Type} and {@link
* TypeBearer}.</p>
*/
public abstract class BaseMachine implements Machine {
/* {@code non-null;} the prototype for the associated method */
private final Prototype prototype;
/** {@code non-null;} primary arguments */
private TypeBearer[] args;
/** {@code >= 0;} number of primary arguments */
private int argCount;
/** {@code null-ok;} type of the operation, if salient */
private Type auxType;
/** auxiliary {@code int} argument */
private int auxInt;
/** {@code null-ok;} auxiliary constant argument */
private Constant auxCst;
/** auxiliary branch target argument */
private int auxTarget;
/** {@code null-ok;} auxiliary switch cases argument */
private SwitchList auxCases;
/** {@code null-ok;} auxiliary initial value list for newarray */
private ArrayList<Constant> auxInitValues;
/** {@code >= -1;} last local accessed */
private int localIndex;
/** {@code null-ok;} local target spec, if salient and calculated */
private RegisterSpec localTarget;
/** {@code non-null;} results */
private TypeBearer[] results;
/**
* {@code >= -1;} count of the results, or {@code -1} if no results
* have been set
*/
private int resultCount;
/**
* Constructs an instance.
*
* @param prototype {@code non-null;} the prototype for the associated method
*/
public BaseMachine(Prototype prototype) {
if (prototype == null) {
throw new NullPointerException("prototype == null");
}
this.prototype = prototype;
args = new TypeBearer[10];
results = new TypeBearer[6];
clearArgs();
}
/** {@inheritDoc} */
public Prototype getPrototype() {
return prototype;
}
/** {@inheritDoc} */
public final void clearArgs() {
argCount = 0;
auxType = null;
auxInt = 0;
auxCst = null;
auxTarget = 0;
auxCases = null;
auxInitValues = null;
localIndex = -1;
localTarget = null;
resultCount = -1;
}
/** {@inheritDoc} */
public final void popArgs(Frame frame, int count) {
ExecutionStack stack = frame.getStack();
clearArgs();
if (count > args.length) {
// Grow args, and add a little extra room to grow even more.
args = new TypeBearer[count + 10];
}
for (int i = count - 1; i >= 0; i--) {
args[i] = stack.pop();
}
argCount = count;
}
/** {@inheritDoc} */
public void popArgs(Frame frame, Prototype prototype) {
StdTypeList types = prototype.getParameterTypes();
int size = types.size();
// Use the above method to do the actual popping...
popArgs(frame, size);
// ...and then verify the popped types.
for (int i = 0; i < size; i++) {
if (! Merger.isPossiblyAssignableFrom(types.getType(i), args[i])) {
throw new SimException("at stack depth " + (size - 1 - i) +
", expected type " + types.getType(i).toHuman() +
" but found " + args[i].getType().toHuman());
}
}
}
public final void popArgs(Frame frame, Type type) {
// Use the above method to do the actual popping...
popArgs(frame, 1);
// ...and then verify the popped type.
if (! Merger.isPossiblyAssignableFrom(type, args[0])) {
throw new SimException("expected type " + type.toHuman() +
" but found " + args[0].getType().toHuman());
}
}
/** {@inheritDoc} */
public final void popArgs(Frame frame, Type type1, Type type2) {
// Use the above method to do the actual popping...
popArgs(frame, 2);
// ...and then verify the popped types.
if (! Merger.isPossiblyAssignableFrom(type1, args[0])) {
throw new SimException("expected type " + type1.toHuman() +
" but found " + args[0].getType().toHuman());
}
if (! Merger.isPossiblyAssignableFrom(type2, args[1])) {
throw new SimException("expected type " + type2.toHuman() +
" but found " + args[1].getType().toHuman());
}
}
/** {@inheritDoc} */
public final void popArgs(Frame frame, Type type1, Type type2,
Type type3) {
// Use the above method to do the actual popping...
popArgs(frame, 3);
// ...and then verify the popped types.
if (! Merger.isPossiblyAssignableFrom(type1, args[0])) {
throw new SimException("expected type " + type1.toHuman() +
" but found " + args[0].getType().toHuman());
}
if (! Merger.isPossiblyAssignableFrom(type2, args[1])) {
throw new SimException("expected type " + type2.toHuman() +
" but found " + args[1].getType().toHuman());
}
if (! Merger.isPossiblyAssignableFrom(type3, args[2])) {
throw new SimException("expected type " + type2.toHuman() +
" but found " + args[2].getType().toHuman());
}
}
/** {@inheritDoc} */
public final void localArg(Frame frame, int idx) {
clearArgs();
args[0] = frame.getLocals().get(idx);
argCount = 1;
localIndex = idx;
}
/** {@inheritDoc} */
public final void auxType(Type type) {
auxType = type;
}
/** {@inheritDoc} */
public final void auxIntArg(int value) {
auxInt = value;
}
/** {@inheritDoc} */
public final void auxCstArg(Constant cst) {
if (cst == null) {
throw new NullPointerException("cst == null");
}
auxCst = cst;
}
/** {@inheritDoc} */
public final void auxTargetArg(int target) {
auxTarget = target;
}
/** {@inheritDoc} */
public final void auxSwitchArg(SwitchList cases) {
if (cases == null) {
throw new NullPointerException("cases == null");
}
auxCases = cases;
}
/** {@inheritDoc} */
public final void auxInitValues(ArrayList<Constant> initValues) {
auxInitValues = initValues;
}
/** {@inheritDoc} */
public final void localTarget(int idx, Type type, LocalItem local) {
localTarget = RegisterSpec.makeLocalOptional(idx, type, local);
}
/**
* Gets the number of primary arguments.
*
* @return {@code >= 0;} the number of primary arguments
*/
protected final int argCount() {
return argCount;
}
/**
* Gets the width of the arguments (where a category-2 value counts as
* two).
*
* @return {@code >= 0;} the argument width
*/
protected final int argWidth() {
int result = 0;
for (int i = 0; i < argCount; i++) {
result += args[i].getType().getCategory();
}
return result;
}
/**
* Gets the {@code n}th primary argument.
*
* @param n {@code >= 0, < argCount();} which argument
* @return {@code non-null;} the indicated argument
*/
protected final TypeBearer arg(int n) {
if (n >= argCount) {
throw new IllegalArgumentException("n >= argCount");
}
try {
return args[n];
} catch (ArrayIndexOutOfBoundsException ex) {
// Translate the exception.
throw new IllegalArgumentException("n < 0");
}
}
/**
* Gets the type auxiliary argument.
*
* @return {@code null-ok;} the salient type
*/
protected final Type getAuxType() {
return auxType;
}
/**
* Gets the {@code int} auxiliary argument.
*
* @return the argument value
*/
protected final int getAuxInt() {
return auxInt;
}
/**
* Gets the constant auxiliary argument.
*
* @return {@code null-ok;} the argument value
*/
protected final Constant getAuxCst() {
return auxCst;
}
/**
* Gets the branch target auxiliary argument.
*
* @return the argument value
*/
protected final int getAuxTarget() {
return auxTarget;
}
/**
* Gets the switch cases auxiliary argument.
*
* @return {@code null-ok;} the argument value
*/
protected final SwitchList getAuxCases() {
return auxCases;
}
/**
* Gets the init values auxiliary argument.
*
* @return {@code null-ok;} the argument value
*/
protected final ArrayList<Constant> getInitValues() {
return auxInitValues;
}
/**
* Gets the last local index accessed.
*
* @return {@code >= -1;} the salient local index or {@code -1} if none
* was set since the last time {@link #clearArgs} was called
*/
protected final int getLocalIndex() {
return localIndex;
}
/**
* Gets the target local register spec of the current operation, if any.
* The local target spec is the combination of the values indicated
* by a previous call to {@link #localTarget} with the type of what
* should be the sole result set by a call to {@link #setResult} (or
* the combination {@link #clearResult} then {@link #addResult}.
*
* @return {@code null-ok;} the salient register spec or {@code null} if no
* local target was set since the last time {@link #clearArgs} was
* called
*/
protected final RegisterSpec getLocalTarget() {
if (localTarget == null) {
return null;
}
if (resultCount != 1) {
throw new SimException("local target with " +
((resultCount == 0) ? "no" : "multiple") + " results");
}
TypeBearer result = results[0];
Type resultType = result.getType();
Type localType = localTarget.getType();
if (resultType == localType) {
return localTarget;
}
if (! Merger.isPossiblyAssignableFrom(localType, resultType)) {
// The result and local types are inconsistent. Complain!
throwLocalMismatch(resultType, localType);
return null;
}
if (localType == Type.OBJECT) {
/*
* The result type is more specific than the local type,
* so use that instead.
*/
localTarget = localTarget.withType(result);
}
return localTarget;
}
/**
* Clears the results.
*/
protected final void clearResult() {
resultCount = 0;
}
/**
* Sets the results list to be the given single value.
*
* <p><b>Note:</b> If there is more than one result value, the
* others may be added by using {@link #addResult}.</p>
*
* @param result {@code non-null;} result value
*/
protected final void setResult(TypeBearer result) {
if (result == null) {
throw new NullPointerException("result == null");
}
results[0] = result;
resultCount = 1;
}
/**
* Adds an additional element to the list of results.
*
* @see #setResult
*
* @param result {@code non-null;} result value
*/
protected final void addResult(TypeBearer result) {
if (result == null) {
throw new NullPointerException("result == null");
}
results[resultCount] = result;
resultCount++;
}
/**
* Gets the count of results. This throws an exception if results were
* never set. (Explicitly clearing the results counts as setting them.)
*
* @return {@code >= 0;} the count
*/
protected final int resultCount() {
if (resultCount < 0) {
throw new SimException("results never set");
}
return resultCount;
}
/**
* Gets the width of the results (where a category-2 value counts as
* two).
*
* @return {@code >= 0;} the result width
*/
protected final int resultWidth() {
int width = 0;
for (int i = 0; i < resultCount; i++) {
width += results[i].getType().getCategory();
}
return width;
}
/**
* Gets the {@code n}th result value.
*
* @param n {@code >= 0, < resultCount();} which result
* @return {@code non-null;} the indicated result value
*/
protected final TypeBearer result(int n) {
if (n >= resultCount) {
throw new IllegalArgumentException("n >= resultCount");
}
try {
return results[n];
} catch (ArrayIndexOutOfBoundsException ex) {
// Translate the exception.
throw new IllegalArgumentException("n < 0");
}
}
/**
* Stores the results of the latest operation into the given frame. If
* there is a local target (see {@link #localTarget}), then the sole
* result is stored to that target; otherwise any results are pushed
* onto the stack.
*
* @param frame {@code non-null;} frame to operate on
*/
protected final void storeResults(Frame frame) {
if (resultCount < 0) {
throw new SimException("results never set");
}
if (resultCount == 0) {
// Nothing to do.
return;
}
if (localTarget != null) {
/*
* Note: getLocalTarget() doesn't necessarily return
* localTarget directly.
*/
frame.getLocals().set(getLocalTarget());
} else {
ExecutionStack stack = frame.getStack();
for (int i = 0; i < resultCount; i++) {
stack.push(results[i]);
}
}
}
/**
* Throws an exception that indicates a mismatch in local variable
* types.
*
* @param found {@code non-null;} the encountered type
* @param local {@code non-null;} the local variable's claimed type
*/
public static void throwLocalMismatch(TypeBearer found,
TypeBearer local) {
throw new SimException("local variable type mismatch: " +
"attempt to set or access a value of type " +
found.toHuman() +
" using a local variable of type " +
local.toHuman() +
". This is symptomatic of .class transformation tools " +
"that ignore local variable information.");
}
}