/**
* Creates a JMultiExpression from a set of JExpressionStatements, optionally terminated by a
* JReturnStatement. If the method doesn't match this pattern, it returns <code>null</code>.
*
* <p>If a method has a non-void return statement and can be represented as a multi-expression,
* the output of the multi-expression will be the return expression of the method. If the method
* is void, the output of the multi-expression should be considered undefined.
*/
private JMultiExpression createMultiExpressionFromBody(
JMethodBody body, boolean ignoringReturnValue) {
JMultiExpression multi = new JMultiExpression(body.getSourceInfo());
CloneCalleeExpressionVisitor cloner = new CloneCalleeExpressionVisitor();
for (JStatement stmt : body.getStatements()) {
if (stmt instanceof JExpressionStatement) {
JExpressionStatement exprStmt = (JExpressionStatement) stmt;
JExpression expr = exprStmt.getExpr();
JExpression clone = cloner.cloneExpression(expr);
multi.addExpressions(clone);
} else if (stmt instanceof JReturnStatement) {
JReturnStatement returnStatement = (JReturnStatement) stmt;
JExpression expr = returnStatement.getExpr();
if (expr != null) {
if (!ignoringReturnValue || expr.hasSideEffects()) {
JExpression clone = cloner.cloneExpression(expr);
clone = maybeCast(clone, body.getMethod().getType());
multi.addExpressions(clone);
}
}
// We hit an unconditional return; no need to evaluate anything else.
break;
} else {
// Any other kind of statement won't be inlinable.
return null;
}
}
return multi;
}
/**
* Returns the ending statement for a method based on an expression. If the return type is void
* then the ending statement just executes the expression otherwise it returns it.
*/
public static JStatement makeMethodEndStatement(JType returnType, JExpression expression) {
// TODO(rluble): Check if something needs to be done here regarding boxing/unboxing/coercions
// when one of the types of expression and returnType is a boxed type and the other a primitive
// type or both are primitive of differnent coerceable types. Add the proper tests first.
return returnType == JPrimitiveType.VOID
? expression.makeStatement()
: expression.makeReturnStatement();
}
private JExpression maskUndefined(JExpression lhs) {
assert ((JReferenceType) lhs.getType()).canBeNull();
JMethod maskMethod = program.getIndexedMethod("Cast.maskUndefined");
JMethodCall lhsCall = new JMethodCall(lhs.getSourceInfo(), null, maskMethod, lhs.getType());
lhsCall.addArg(lhs);
return lhsCall;
}
@Override
public boolean hasSideEffects() {
for (JExpression expression : expressions) {
if (expression.hasSideEffects()) {
return true;
}
}
return false;
}
/**
* Insert an implicit cast if the types differ; it might get optimized out later, but in some
* cases it will force correct math evaluation.
*/
private JExpression maybeCast(JExpression exp, JType targetType) {
if (targetType instanceof JReferenceType) {
assert exp.getType() instanceof JReferenceType;
targetType = merge((JReferenceType) exp.getType(), (JReferenceType) targetType);
}
if (!program.typeOracle.castSucceedsTrivially(exp.getType(), targetType)) {
exp = new JCastOperation(exp.getSourceInfo(), targetType, exp);
}
return exp;
}
@Override
public void endVisit(JDeclarationStatement x, Context ctx) {
super.endVisit(x, ctx);
lValues.pop();
// The variable may have been pruned.
if (isVariablePruned(x.getVariableRef().getTarget())) {
JExpression replacement =
makeReplacementForAssignment(x.getSourceInfo(), x.getVariableRef(), x.getInitializer());
ctx.replaceMe(replacement.makeStatement());
}
}
@Override
JsLiteral translate(JExpression literal) {
SourceInfo sourceInfo = literal.getSourceInfo();
long[] values = LongLib.getAsLongArray(((JLongLiteral) literal).getValue());
if (values.length == 1) {
return new JsNumberLiteral(literal.getSourceInfo(), ((JLongLiteral) literal).getValue());
}
JsObjectLiteral objectLiteral = new JsObjectLiteral(sourceInfo);
objectLiteral.setInternable();
assert values.length == names.length;
for (int i = 0; i < names.length; i++) {
addPropertyToObject(sourceInfo, names[i], values[i], objectLiteral);
}
return objectLiteral;
}
/**
* Transform a call to a pruned instance method (or static impl) into a call to the null method,
* which will be used to replace <code>x</code>.
*/
public static JMethodCall transformToNullMethodCall(JMethodCall x, JProgram program) {
JExpression instance = x.getInstance();
List<JExpression> args = x.getArgs();
if (program.isStaticImpl(x.getTarget())) {
instance = args.get(0);
args = args.subList(1, args.size());
} else {
/*
* We assert that method must be non-static, otherwise it would have been
* rescued.
*/
// assert !x.getTarget().isStatic();
/*
* HACK HACK HACK: ControlFlowAnalyzer has special hacks for dealing with
* ClassLiterals, which causes the body of ClassLiteralHolder's clinit to
* never be rescured. This in turn causes invalid references to static
* methods, which violates otherwise good assumptions about compiler
* operation.
*
* TODO: Remove this when ControlFlowAnalyzer doesn't special-case
* CLH.clinit().
*/
if (x.getTarget().isStatic() && instance == null) {
instance = program.getLiteralNull();
}
}
assert (instance != null);
if (!instance.hasSideEffects()) {
instance = program.getLiteralNull();
}
JMethodCall newCall =
new JMethodCall(
x.getSourceInfo(),
instance,
program.getNullMethod(),
primitiveTypeOrNullTypeOrArray(program, x.getType()));
// Retain the original arguments, they will be evaluated for side effects.
for (JExpression arg : args) {
if (arg.hasSideEffects()) {
newCall.addArg(arg);
}
}
return newCall;
}
@Override
public void endVisit(JThrowStatement x, Context ctx) {
assert jseType != null;
JExpression expr = x.getExpr();
// Optimization: unwrap not needed if "new BlahException()"
if (expr instanceof JNewInstance && !expr.getType().equals(jseType)) {
return;
}
// Optimization: unwrap not needed if expression can never be JavaScriptException
if (!program.typeOracle.canTheoreticallyCast((JReferenceType) expr.getType(), jseType)) {
return;
}
// throw x; -> throw Exceptions.unwrap(x);
ctx.replaceMe(createUnwrappedThrow(x));
}
/**
* Creates a multi expression from a list of expressions, removing expressions that do not have
* side effects if possible.
*/
public static JExpression createOptimizedMultiExpression(
boolean ignoringResult, List<JExpression> expressions) {
int numberOfExpressions = expressions.size();
JExpression result = expressions.get(numberOfExpressions - 1);
numberOfExpressions = expressions.size();
if (numberOfExpressions == 0) {
return new JMultiExpression(SourceOrigin.UNKNOWN);
}
expressions =
Lists.newArrayList(
Collections2.filter(
expressions.subList(0, numberOfExpressions - 1),
Predicates.and(
Predicates.notNull(),
new Predicate<JExpression>() {
@Override
public boolean apply(JExpression expression) {
return expression.hasSideEffects();
}
})));
if (result != null && (!ignoringResult || result.hasSideEffects())) {
expressions.add(result);
}
if (expressions.size() == 1) {
// Do not create a multi expression if it consists only of the result.
return expressions.iterator().next();
}
SourceInfo info =
expressions.size() > 0 ? expressions.get(0).getSourceInfo() : SourceOrigin.UNKNOWN;
return new JMultiExpression(info, expressions);
}
/**
* Installs the initial load sequence into AsyncFragmentLoader.BROWSER_LOADER. The initializer
* looks like this:
*
* <pre>
* AsyncFragmentLoader BROWSER_LOADER = makeBrowserLoader(1, new int[]{});
* </pre>
*
* The second argument (<code>new int[]</code>) gets replaced by an array corresponding to <code>
* initialLoadSequence</code>.
*/
private static void installInitialLoadSequenceField(
JProgram program, LinkedHashSet<JRunAsync> initialLoadSequence) {
// Arg 1 is initialized in the source as "new int[]{}".
JMethodCall call = ReplaceRunAsyncs.getBrowserLoaderConstructor(program);
JExpression arg1 = call.getArgs().get(1);
assert arg1 instanceof JNewArray;
JArrayType arrayType = program.getTypeArray(JPrimitiveType.INT);
assert ((JNewArray) arg1).getArrayType() == arrayType;
List<JExpression> initializers = new ArrayList<JExpression>(initialLoadSequence.size());
// RunAsyncFramentIndex will later be replaced by the fragment the async is in.
// TODO(rluble): this approach is not very clean, ideally the load sequence should be
// installed AFTER code splitting when the fragment ids are known; rather than inserting
// a placeholder in the AST and patching the ast later.
for (JRunAsync runAsync : initialLoadSequence) {
initializers.add(
new JNumericEntry(
call.getSourceInfo(), "RunAsyncFragmentIndex", runAsync.getRunAsyncId()));
}
JNewArray newArray =
JNewArray.createArrayWithInitializers(
arg1.getSourceInfo(), arrayType, Lists.newArrayList(initializers));
call.setArg(1, newArray);
}
/**
* Transform a reference to a pruned instance field into a reference to the null field, which will
* be used to replace <code>x</code>.
*/
public static JFieldRef transformToNullFieldRef(JFieldRef x, JProgram program) {
JExpression instance = x.getInstance();
/*
* We assert that field must be non-static if it's an rvalue, otherwise it
* would have been rescued.
*/
// assert !x.getField().isStatic();
/*
* HACK HACK HACK: ControlFlowAnalyzer has special hacks for dealing with
* ClassLiterals, which causes the body of ClassLiteralHolder's clinit to
* never be rescured. This in turn causes invalid references to static
* methods, which violates otherwise good assumptions about compiler
* operation.
*
* TODO: Remove this when ControlFlowAnalyzer doesn't special-case
* CLH.clinit().
*/
if (x.getField().isStatic() && instance == null) {
instance = program.getLiteralNull();
}
assert instance != null;
if (!instance.hasSideEffects()) {
instance = program.getLiteralNull();
}
JFieldRef fieldRef =
new JFieldRef(
x.getSourceInfo(),
instance,
program.getNullField(),
x.getEnclosingType(),
primitiveTypeOrNullTypeOrArray(program, x.getType()));
return fieldRef;
}
/** Returns an ast node representing the expression {@code expression != null}. */
public static JExpression createOptimizedNotNullComparison(
JProgram program, SourceInfo info, JExpression expression) {
JReferenceType type = (JReferenceType) expression.getType();
if (type.isNullType()) {
return program.getLiteralBoolean(false);
}
if (!type.canBeNull()) {
return createOptimizedMultiExpression(expression, program.getLiteralBoolean(true));
}
return new JBinaryOperation(
info,
program.getTypePrimitiveBoolean(),
JBinaryOperator.NEQ,
expression,
program.getLiteralNull());
}
@Override
public void endVisit(JBinaryOperation x, Context ctx) {
JBinaryOperator op = x.getOp();
if (op != JBinaryOperator.EQ && op != JBinaryOperator.NEQ) {
return;
}
JExpression lhs = x.getLhs();
JExpression rhs = x.getRhs();
JType lhsType = lhs.getType();
JType rhsType = rhs.getType();
if (!(lhsType instanceof JReferenceType)) {
assert !(rhsType instanceof JReferenceType);
return;
}
StringStatus lhsStatus = getStringStatus((JReferenceType) lhsType);
StringStatus rhsStatus = getStringStatus((JReferenceType) rhsType);
int strat = COMPARISON_STRAT[lhsStatus.getIndex()][rhsStatus.getIndex()];
switch (strat) {
case STRAT_TRIPLE:
{
if (canBeNull(lhs) && canBeNull(rhs)) {
/*
* If it's possible for one side to be null and the other side
* undefined, then mask both sides.
*/
lhs = maskUndefined(lhs);
rhs = maskUndefined(rhs);
}
JBinaryOperation binOp =
new JBinaryOperation(x.getSourceInfo(), x.getType(), x.getOp(), lhs, rhs);
ctx.replaceMe(binOp);
break;
}
case STRAT_DOUBLE:
{
boolean lhsNullLit = lhs == program.getLiteralNull();
boolean rhsNullLit = rhs == program.getLiteralNull();
if ((lhsNullLit && rhsStatus == StringStatus.NOTSTRING)
|| (rhsNullLit && lhsStatus == StringStatus.NOTSTRING)) {
/*
* If either side is a null literal and the other is non-String,
* replace with a null-check.
*/
String methodName;
if (op == JBinaryOperator.EQ) {
methodName = "Cast.isNull";
} else {
methodName = "Cast.isNotNull";
}
JMethod isNullMethod = program.getIndexedMethod(methodName);
JMethodCall call = new JMethodCall(x.getSourceInfo(), null, isNullMethod);
call.addArg(lhsNullLit ? rhs : lhs);
ctx.replaceMe(call);
} else {
// Replace with a call to Cast.jsEquals, which does a == internally.
String methodName;
if (op == JBinaryOperator.EQ) {
methodName = "Cast.jsEquals";
} else {
methodName = "Cast.jsNotEquals";
}
JMethod eqMethod = program.getIndexedMethod(methodName);
JMethodCall call = new JMethodCall(x.getSourceInfo(), null, eqMethod);
call.addArgs(lhs, rhs);
ctx.replaceMe(call);
}
break;
}
}
}
@Override
JsLiteral translate(JExpression literal) {
return new JsStringLiteral(literal.getSourceInfo(), ((JStringLiteral) literal).getValue());
}
@Override
JsLiteral translate(JExpression literal) {
return new JsNumberLiteral(literal.getSourceInfo(), ((JIntLiteral) literal).getValue());
}
public static void replaceMethodBody(JMethod method, JExpression returnValue) {
JMethodBody body = (JMethodBody) method.getBody();
JBlock block = body.getBlock();
block.clear();
block.addStmt(returnValue.makeReturnStatement());
}
private static boolean canBeNull(JExpression x) {
return ((JReferenceType) x.getType()).canBeNull();
}
// Arguments for pruned parameters will be pushed right into a multiexpression that will be
// evaluated with the next arg, e.g. m(arg1, (prunnedArg2, prunnedArg3, arg4)).
private void maybeReplaceForPrunedParameters(JMethodCall x, Context ctx) {
if (!priorParametersByMethod.containsKey(x.getTarget())) {
// No parameter was pruned.
return;
}
JMethodCall replacementCall = x.cloneWithoutParameters();
assert !x.getTarget().canBePolymorphic();
List<JParameter> originalParams = priorParametersByMethod.get(x.getTarget());
// The method and the call agree in the number of parameters.
assert originalParams.size() == x.getArgs().size();
// Traverse the call arguments left to right.
SourceInfo sourceInfo = x.getSourceInfo();
JMultiExpression unevaluatedArgumentsForPrunedParameters = new JMultiExpression(sourceInfo);
List<JExpression> args = x.getArgs();
for (int currentArgumentIndex = 0;
currentArgumentIndex < args.size();
++currentArgumentIndex) {
JExpression arg = args.get(currentArgumentIndex);
// If the parameter was not pruned .
if (referencedNonTypes.contains(originalParams.get(currentArgumentIndex))) {
// Add the current argument to the list of unevaluated arguments and pass the multi
// expression to the call.
unevaluatedArgumentsForPrunedParameters.addExpressions(arg);
replacementCall.addArg(unevaluatedArgumentsForPrunedParameters);
// Reset the accumulating multi expression.
unevaluatedArgumentsForPrunedParameters = new JMultiExpression(sourceInfo);
} else if (arg.hasSideEffects()) {
// If the argument was pruned and has sideffects accumulate it; otherwise discard.
unevaluatedArgumentsForPrunedParameters.addExpressions(arg);
}
}
if (unevaluatedArgumentsForPrunedParameters.isEmpty()) {
// We are done, all (side effectful) parameters have been evaluated.
ctx.replaceMe(replacementCall);
return;
}
// If the last few parameters where pruned, we need to evaluate the (side effectful) arguments
// for those parameters.
if (replacementCall.getArgs().isEmpty()) {
// All parameters have been pruned, replace by (prunedArg1, ..., prunedArgn, m()).
unevaluatedArgumentsForPrunedParameters.addExpressions(replacementCall);
ctx.replaceMe(unevaluatedArgumentsForPrunedParameters);
return;
}
// Some parameters have been pruned from the end, replace by
// m(arg1,..., (lastArg = lastUnprunedArg, remainingArgs, lastArg))
JExpression lastArg = Iterables.getLast(replacementCall.getArgs());
JLocal tempVar =
createTempLocal(
sourceInfo,
Iterables.getLast(Iterables.filter(originalParams, Predicates.in(referencedNonTypes)))
.getType());
unevaluatedArgumentsForPrunedParameters.addExpressions(
0,
JProgram.createAssignment(
lastArg.getSourceInfo(), new JLocalRef(sourceInfo, tempVar), lastArg));
unevaluatedArgumentsForPrunedParameters.addExpressions(new JLocalRef(sourceInfo, tempVar));
replacementCall.setArg(
replacementCall.getArgs().size() - 1, unevaluatedArgumentsForPrunedParameters);
ctx.replaceMe(replacementCall);
}