/*
* Copyright 2008 Google Inc.
*
* 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.google.gwt.dev.jjs.impl;
import com.google.gwt.dev.jjs.SourceInfo;
import com.google.gwt.dev.jjs.ast.Context;
import com.google.gwt.dev.jjs.ast.JArrayRef;
import com.google.gwt.dev.jjs.ast.JArrayType;
import com.google.gwt.dev.jjs.ast.JBinaryOperation;
import com.google.gwt.dev.jjs.ast.JBinaryOperator;
import com.google.gwt.dev.jjs.ast.JCastOperation;
import com.google.gwt.dev.jjs.ast.JCharLiteral;
import com.google.gwt.dev.jjs.ast.JClassType;
import com.google.gwt.dev.jjs.ast.JExpression;
import com.google.gwt.dev.jjs.ast.JInstanceOf;
import com.google.gwt.dev.jjs.ast.JIntLiteral;
import com.google.gwt.dev.jjs.ast.JMethod;
import com.google.gwt.dev.jjs.ast.JMethodCall;
import com.google.gwt.dev.jjs.ast.JModVisitor;
import com.google.gwt.dev.jjs.ast.JNullLiteral;
import com.google.gwt.dev.jjs.ast.JNullType;
import com.google.gwt.dev.jjs.ast.JPrimitiveType;
import com.google.gwt.dev.jjs.ast.JProgram;
import com.google.gwt.dev.jjs.ast.JReferenceType;
import com.google.gwt.dev.jjs.ast.JType;
import com.google.gwt.dev.jjs.ast.JTypeOracle;
import com.google.gwt.dev.jjs.ast.JVisitor;
import com.google.gwt.dev.jjs.ast.js.JsonObject;
import com.google.gwt.dev.jjs.ast.js.JsonObject.JsonPropInit;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.IdentityHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
/**
* Replace cast and instanceof operations with calls to the Cast class. Depends
* on {@link CatchBlockNormalizer}, {@link CompoundAssignmentNormalizer},
* {@link JsoDevirtualizer}, and {@link LongCastNormalizer} having already run.
*
* <p>
* Object and String always get a typeId of 1 and 2, respectively. 0 is reserved
* as the typeId for any classes that can never be instance type of a successful
* dynamic cast.
* </p>
* <p>
* Object and String always get a queryId of 0 and 1, respectively. The 0
* queryId always means "always succeeds". In practice, we never generate an
* explicit cast with a queryId of 0; it is only used for array store checking,
* where the 0 queryId means that anything can be stored into an Object[].
* </p>
* <p>
* JavaScriptObject and subclasses have no typeId at all. JavaScriptObject has a
* queryId of -1, which again is only used for array store checking, to ensure
* that a non-JSO is not stored into a JavaScriptObject[].
* </p>
*/
public class CastNormalizer {
private class AssignTypeIdsVisitor extends JVisitor {
Set<JReferenceType> alreadyRan = new HashSet<JReferenceType>();
private List<JReferenceType> instantiableTypes = new ArrayList<JReferenceType>();
private final List<JArrayType> instantiatedArrayTypes = new ArrayList<JArrayType>();
private List<JsonObject> jsonObjects = new ArrayList<JsonObject>();
private int nextQueryId = 0;
private Map<JReferenceType, Set<JReferenceType>> queriedTypes = new IdentityHashMap<JReferenceType, Set<JReferenceType>>();
{
JTypeOracle typeOracle = program.typeOracle;
for (JArrayType arrayType : program.getAllArrayTypes()) {
if (typeOracle.isInstantiatedType(arrayType)) {
instantiatedArrayTypes.add(arrayType);
}
}
// Reserve query id 0 for java.lang.Object (for array stores on JSOs).
recordCastInternal(program.getTypeJavaLangObject(),
program.getTypeJavaLangObject());
// Reserve query id 1 for java.lang.String to facilitate the mashup case.
// Multiple GWT modules need to modify String's prototype the same way.
recordCastInternal(program.getTypeJavaLangString(),
program.getTypeJavaLangObject());
}
public void computeTypeIds() {
// the 0th entry is the "always false" entry
instantiableTypes.add(null);
jsonObjects.add(new JsonObject(program.createSourceInfoSynthetic(
AssignTypeIdsVisitor.class, "always-false typeinfo entry"),
program.getJavaScriptObject()));
/*
* Do String first to reserve typeIds 1 and 2 for Object and String,
* respectively. This ensures consistent modification of String's
* prototype.
*/
computeSourceType(program.getTypeJavaLangString());
assert (instantiableTypes.size() == 3);
/*
* Compute the list of classes than can successfully satisfy cast
* requests, along with the set of types they can be successfully cast to.
* Do it in super type order.
*/
for (JReferenceType type : program.getDeclaredTypes()) {
if (type instanceof JClassType) {
computeSourceType(type);
}
}
for (JArrayType type : program.getAllArrayTypes()) {
computeSourceType(type);
}
// pass our info to JProgram
program.initTypeInfo(instantiableTypes, jsonObjects);
// JSO's maker queryId is -1 (used for array stores).
JClassType jsoType = program.getJavaScriptObject();
if (jsoType != null) {
queryIds.put(jsoType, -1);
}
program.recordQueryIds(queryIds);
}
/*
* If this expression could possibly generate an ArrayStoreException, we
* must record a query on the element type being assigned to.
*/
@Override
public void endVisit(JBinaryOperation x, Context ctx) {
if (x.getOp() == JBinaryOperator.ASG && x.getLhs() instanceof JArrayRef) {
// first, calculate the transitive closure of all possible runtime types
// the lhs could be
JExpression instance = ((JArrayRef) x.getLhs()).getInstance();
if (instance.getType() instanceof JNullType) {
// will generate a null pointer exception instead
return;
}
JArrayType lhsArrayType = (JArrayType) instance.getType();
JType elementType = lhsArrayType.getElementType();
// primitives are statically correct
if (!(elementType instanceof JReferenceType)) {
return;
}
// element type being final means the assignment is statically correct
if (((JReferenceType) elementType).isFinal()) {
return;
}
/*
* For every instantiated array type that could -in theory- be the
* runtime type of the lhs, we must record a cast from the rhs to the
* prospective element type of the lhs.
*/
JTypeOracle typeOracle = program.typeOracle;
JType rhsType = x.getRhs().getType();
assert (rhsType instanceof JReferenceType);
JReferenceType refRhsType = (JReferenceType) rhsType;
for (JArrayType arrayType : instantiatedArrayTypes) {
if (typeOracle.canTheoreticallyCast(arrayType, lhsArrayType)) {
JType itElementType = arrayType.getElementType();
if (itElementType instanceof JReferenceType) {
recordCastInternal((JReferenceType) itElementType, refRhsType);
}
}
}
}
}
@Override
public void endVisit(JCastOperation x, Context ctx) {
if (disableCastChecking) {
return;
}
if (x.getCastType() != program.getTypeNull()) {
recordCast(x.getCastType(), x.getExpr());
}
}
@Override
public void endVisit(JInstanceOf x, Context ctx) {
assert (x.getTestType() != program.getTypeNull());
recordCast(x.getTestType(), x.getExpr());
}
/**
* Create the data for JSON table to capture the mapping from a class to its
* query types.
*/
private void computeSourceType(JReferenceType type) {
if (type == null || alreadyRan.contains(type)) {
return;
}
alreadyRan.add(type);
// Visit super type.
computeSourceType(type.getSuperClass());
if (!program.typeOracle.isInstantiatedType(type)
|| program.isJavaScriptObject(type)) {
return;
}
// Find all possible query types which I can satisfy
Set<JReferenceType> yesSet = null;
// NOTE: non-deterministic iteration over HashSet and HashMap. This is
// okay here because we're just adding things to another HashSet.
for (JReferenceType qType : queriedTypes.keySet()) {
Set<JReferenceType> querySet = queriedTypes.get(qType);
if (program.typeOracle.canTriviallyCast(type, qType)) {
for (JReferenceType argType : querySet) {
if (program.typeOracle.canTriviallyCast(type, argType)) {
if (yesSet == null) {
yesSet = new HashSet<JReferenceType>();
}
yesSet.add(qType);
break;
}
}
}
}
// Use a sparse array to sort my yes set.
JReferenceType[] yesArray = new JReferenceType[nextQueryId];
if (yesSet != null) {
for (JReferenceType yesType : yesSet) {
yesArray[queryIds.get(yesType)] = yesType;
}
}
// Create a sparse lookup object.
SourceInfo sourceInfo = program.createSourceInfoSynthetic(
AssignTypeIdsVisitor.class, "typeinfo lookup");
JsonObject jsonObject = new JsonObject(sourceInfo,
program.getJavaScriptObject());
// Start at 1; 0 is Object and always true.
for (int i = 1; i < nextQueryId; ++i) {
if (yesArray[i] != null) {
JIntLiteral labelExpr = program.getLiteralInt(i);
JIntLiteral valueExpr = program.getLiteralInt(1);
jsonObject.propInits.add(new JsonPropInit(sourceInfo, labelExpr,
valueExpr));
}
}
/*
* Don't add an entry for empty answer sets, except for Object and String
* which require typeIds.
*/
if (jsonObject.propInits.isEmpty()
&& type != program.getTypeJavaLangObject()
&& type != program.getTypeJavaLangString()) {
return;
}
// add an entry for me
instantiableTypes.add(type);
jsonObjects.add(jsonObject);
}
private void recordCast(JType targetType, JExpression rhs) {
if (targetType instanceof JReferenceType) {
// unconditional cast b/c it would've been a semantic error earlier
JReferenceType rhsType = (JReferenceType) rhs.getType();
// don't record a type for trivial casts that won't generate code
if (rhsType instanceof JClassType) {
if (program.typeOracle.canTriviallyCast(rhsType,
(JReferenceType) targetType)) {
return;
}
}
// If the target type is a JavaScriptObject, don't record an id.
if (program.isJavaScriptObject(targetType)) {
return;
}
recordCastInternal((JReferenceType) targetType, rhsType);
}
}
private void recordCastInternal(JReferenceType targetType,
JReferenceType rhsType) {
JReferenceType toType = targetType;
Set<JReferenceType> querySet = queriedTypes.get(toType);
if (querySet == null) {
queryIds.put(toType, nextQueryId++);
querySet = new HashSet<JReferenceType>();
queriedTypes.put(toType, querySet);
}
querySet.add(rhsType);
}
}
/**
* Explicitly convert any char or long type expressions within a concat
* operation into strings because normal JavaScript conversion does not work
* correctly.
*/
private class ConcatVisitor extends JModVisitor {
@Override
public void endVisit(JBinaryOperation x, Context ctx) {
if (x.getOp() == JBinaryOperator.CONCAT) {
JExpression newLhs = convertString(x.getLhs());
JExpression newRhs = convertString(x.getRhs());
if (newLhs != x.getLhs() || newRhs != x.getRhs()) {
JBinaryOperation newExpr = new JBinaryOperation(x.getSourceInfo(),
program.getTypeJavaLangString(), JBinaryOperator.CONCAT, newLhs,
newRhs);
ctx.replaceMe(newExpr);
}
} else if (x.getOp() == JBinaryOperator.ASG_CONCAT) {
JExpression newRhs = convertString(x.getRhs());
if (newRhs != x.getRhs()) {
JBinaryOperation newExpr = new JBinaryOperation(x.getSourceInfo(),
program.getTypeJavaLangString(), JBinaryOperator.ASG_CONCAT,
x.getLhs(), newRhs);
ctx.replaceMe(newExpr);
}
}
}
private JExpression convertString(JExpression expr) {
JPrimitiveType charType = program.getTypePrimitiveChar();
if (expr.getType() == charType) {
if (expr instanceof JCharLiteral) {
JCharLiteral charLit = (JCharLiteral) expr;
return program.getLiteralString(expr.getSourceInfo(),
new char[] {charLit.getValue()});
} else {
// Replace with Cast.charToString(c)
JMethodCall call = new JMethodCall(expr.getSourceInfo(), null,
program.getIndexedMethod("Cast.charToString"));
call.addArg(expr);
return call;
}
} else if (expr.getType() == program.getTypePrimitiveLong()) {
// Replace with LongLib.toString(l)
JMethodCall call = new JMethodCall(expr.getSourceInfo(), null,
program.getIndexedMethod("LongLib.toString"));
call.addArg(expr);
return call;
}
return expr;
}
}
/**
* Handle integral divide operations which may have floating point results.
*/
private class DivVisitor extends JModVisitor {
@Override
public void endVisit(JBinaryOperation x, Context ctx) {
JType type = x.getType();
if (x.getOp() == JBinaryOperator.DIV
&& type != program.getTypePrimitiveFloat()
&& type != program.getTypePrimitiveDouble()) {
/*
* If the numerator was already in range, we can assume the output is
* also in range. Therefore, we don't need to do the full conversion,
* but rather a narrowing int conversion instead.
*/
String methodName = "Cast.narrow_" + type.getName();
JMethod castMethod = program.getIndexedMethod(methodName);
JMethodCall call = new JMethodCall(x.getSourceInfo(), null, castMethod,
type);
x.setType(program.getTypePrimitiveDouble());
call.addArg(x);
ctx.replaceMe(call);
}
}
}
/**
* Replaces all casts and instanceof operations with calls to implementation
* methods.
*/
private class ReplaceTypeChecksVisitor extends JModVisitor {
@Override
public void endVisit(JCastOperation x, Context ctx) {
JExpression replaceExpr;
JType toType = x.getCastType();
JExpression expr = x.getExpr();
if (disableCastChecking && toType instanceof JReferenceType) {
ctx.replaceMe(expr);
return;
}
if (toType instanceof JNullType) {
/*
* Magic: a null type cast means the user tried a cast that couldn't
* possibly work. Typically this means either the statically resolvable
* arg type is incompatible with the target type, or the target type was
* globally uninstantiable. We handle this cast by throwing a
* ClassCastException, unless the argument is null.
*/
JMethod method = program.getIndexedMethod("Cast.throwClassCastExceptionUnlessNull");
/*
* Override the type of the magic method with the null type.
*/
JMethodCall call = new JMethodCall(x.getSourceInfo(), null, method,
program.getTypeNull());
call.addArg(expr);
replaceExpr = call;
} else if (toType instanceof JReferenceType) {
JExpression curExpr = expr;
JReferenceType refType = (JReferenceType) toType;
JReferenceType argType = (JReferenceType) expr.getType();
if (program.typeOracle.canTriviallyCast(argType, refType)) {
// just remove the cast
replaceExpr = curExpr;
} else {
JMethod method;
boolean isJsoCast = program.isJavaScriptObject(toType);
if (isJsoCast) {
// A cast to a concrete JSO subtype
method = program.getIndexedMethod("Cast.dynamicCastJso");
} else if (program.typeOracle.getSingleJsoImpls().containsKey(toType)) {
// An interface that should succeed when the object is a JSO
method = program.getIndexedMethod("Cast.dynamicCastAllowJso");
} else {
// A regular cast
method = program.getIndexedMethod("Cast.dynamicCast");
}
// override the type of the called method with the target cast type
JMethodCall call = new JMethodCall(x.getSourceInfo(), null, method,
toType);
call.addArg(curExpr);
if (!isJsoCast) {
JIntLiteral qId = program.getLiteralInt(queryIds.get(refType));
call.addArg(qId);
}
replaceExpr = call;
}
} else {
/*
* See JLS 5.1.3: if a cast narrows from one type to another, we must
* call a narrowing conversion function. EXCEPTION: we currently have no
* way to narrow double to float, so don't bother.
*/
JPrimitiveType tByte = program.getTypePrimitiveByte();
JPrimitiveType tChar = program.getTypePrimitiveChar();
JPrimitiveType tShort = program.getTypePrimitiveShort();
JPrimitiveType tInt = program.getTypePrimitiveInt();
JPrimitiveType tLong = program.getTypePrimitiveLong();
JPrimitiveType tFloat = program.getTypePrimitiveFloat();
JPrimitiveType tDouble = program.getTypePrimitiveDouble();
JType fromType = expr.getType();
String methodName = null;
if (tLong == fromType && tLong != toType) {
if (tByte == toType || tShort == toType || tChar == toType) {
/*
* We need a double call here, one to convert long->int, and another
* one to narrow. Construct the inner call here and fall through to
* do the narrowing conversion.
*/
JMethod castMethod = program.getIndexedMethod("LongLib.toInt");
JMethodCall call = new JMethodCall(x.getSourceInfo(), null,
castMethod);
call.addArg(expr);
expr = call;
fromType = tInt;
} else if (tInt == toType) {
methodName = "LongLib.toInt";
} else if (tFloat == toType || tDouble == toType) {
methodName = "LongLib.toDouble";
}
}
if (toType == tLong && fromType != tLong) {
// Longs get special treatment.
if (tByte == fromType || tShort == fromType || tChar == fromType
|| tInt == fromType) {
methodName = "LongLib.fromInt";
} else if (tFloat == fromType || tDouble == fromType) {
methodName = "LongLib.fromDouble";
}
} else if (tByte == fromType) {
if (tChar == toType) {
methodName = "Cast.narrow_" + toType.getName();
}
} else if (tShort == fromType) {
if (tByte == toType || tChar == toType) {
methodName = "Cast.narrow_" + toType.getName();
}
} else if (tChar == fromType) {
if (tByte == toType || tShort == toType) {
methodName = "Cast.narrow_" + toType.getName();
}
} else if (tInt == fromType) {
if (tByte == toType || tShort == toType || tChar == toType) {
methodName = "Cast.narrow_" + toType.getName();
}
} else if (tFloat == fromType || tDouble == fromType) {
if (tByte == toType || tShort == toType || tChar == toType
|| tInt == toType) {
methodName = "Cast.round_" + toType.getName();
}
}
if (methodName != null) {
JMethod castMethod = program.getIndexedMethod(methodName);
JMethodCall call = new JMethodCall(x.getSourceInfo(), null,
castMethod, toType);
call.addArg(expr);
replaceExpr = call;
} else {
// Just remove the cast
replaceExpr = expr;
}
}
ctx.replaceMe(replaceExpr);
}
@Override
public void endVisit(JInstanceOf x, Context ctx) {
JReferenceType argType = (JReferenceType) x.getExpr().getType();
JReferenceType toType = x.getTestType();
if (program.typeOracle.canTriviallyCast(argType, toType)) {
// trivially true if non-null; replace with a null test
JNullLiteral nullLit = program.getLiteralNull();
JBinaryOperation eq = new JBinaryOperation(x.getSourceInfo(),
program.getTypePrimitiveBoolean(), JBinaryOperator.NEQ,
x.getExpr(), nullLit);
ctx.replaceMe(eq);
} else {
JMethod method;
boolean isJsoCast = false;
if (program.typeOracle.getSingleJsoImpls().containsKey(toType)) {
method = program.getIndexedMethod("Cast.instanceOfOrJso");
} else if (program.isJavaScriptObject(toType)) {
isJsoCast = true;
method = program.getIndexedMethod("Cast.instanceOfJso");
} else {
method = program.getIndexedMethod("Cast.instanceOf");
}
JMethodCall call = new JMethodCall(x.getSourceInfo(), null, method);
call.addArg(x.getExpr());
if (!isJsoCast) {
JIntLiteral qId = program.getLiteralInt(queryIds.get(toType));
call.addArg(qId);
}
ctx.replaceMe(call);
}
}
}
public static void exec(JProgram program, boolean disableCastChecking) {
new CastNormalizer(program, disableCastChecking).execImpl();
}
private final boolean disableCastChecking;
private final JProgram program;
private Map<JReferenceType, Integer> queryIds = new IdentityHashMap<JReferenceType, Integer>();
private CastNormalizer(JProgram program, boolean disableCastChecking) {
this.program = program;
this.disableCastChecking = disableCastChecking;
}
private void execImpl() {
{
ConcatVisitor visitor = new ConcatVisitor();
visitor.accept(program);
}
{
DivVisitor visitor = new DivVisitor();
visitor.accept(program);
}
{
AssignTypeIdsVisitor assigner = new AssignTypeIdsVisitor();
assigner.accept(program);
assigner.computeTypeIds();
}
{
ReplaceTypeChecksVisitor replacer = new ReplaceTypeChecksVisitor();
replacer.accept(program);
}
}
}