@Override
public void endVisit(JsniFieldRef x, Context ctx) {
if (isPruned(x.getField())) {
String ident = x.getIdent();
JField nullField = program.getNullField();
JsniFieldRef nullFieldRef =
new JsniFieldRef(
x.getSourceInfo(), ident, nullField, x.getEnclosingType(), x.isLvalue());
ctx.replaceMe(nullFieldRef);
}
}
@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
public void endVisit(JsniMethodRef x, Context ctx) {
// Redirect JSNI refs to uninstantiable types to the null method.
if (isPruned(x.getTarget())) {
String ident = x.getIdent();
JMethod nullMethod = program.getNullMethod();
JsniMethodRef nullMethodRef =
new JsniMethodRef(x.getSourceInfo(), ident, nullMethod, program.getJavaScriptObject());
ctx.replaceMe(nullMethodRef);
}
}
@Override
public void endVisit(JReturnStatement x, Context ctx) {
info(x);
JReturnStatement toReturn =
new JReturnStatement(
x.getSourceInfo(),
new JMethodCall(
x.getSourceInfo(),
new JThisRef(x.getSourceInfo(), enumType),
enumObfuscatedName));
ctx.replaceMe(toReturn);
}
@Override
public void endVisit(JFieldRef x, Context ctx) {
// Handle l-values at a higher level.
if (lValues.peek() == x) {
return;
}
if (isPruned(x.getField())) {
// The field is gone; replace x by a null field reference.
JFieldRef fieldRef = transformToNullFieldRef(x, program);
ctx.replaceMe(fieldRef);
}
}
@Override
public void endVisit(JParameterRef x, Context ctx) {
int paramIndex = methodCall.getTarget().getParams().indexOf(x.getParameter());
assert paramIndex != -1;
// Replace with a cloned call argument.
CloneExpressionVisitor cloner = new CloneExpressionVisitor();
JExpression arg = methodCall.getArgs().get(paramIndex);
JExpression clone = cloner.cloneExpression(arg);
clone = maybeCast(clone, x.getType());
ctx.replaceMe(clone);
}
@Override
public void endVisit(JMethodCall x, Context ctx) {
JMethod method = x.getTarget();
// Is the method pruned entirely?
if (isPruned(method)) {
/*
* We assert that method must be non-static, otherwise it would have
* been rescued.
*/
ctx.replaceMe(transformToNullMethodCall(x, program));
return;
}
maybeReplaceForPrunedParameters(x, ctx);
}
@Override
public void endVisit(JLocalRef x, Context ctx) {
JLocal originalLocal = x.getLocal();
JLocal newLocal = newLocalsByOriginalLocal.get(originalLocal);
if (newLocal == null) {
newLocal =
JProgram.createLocal(
originalLocal.getSourceInfo(),
originalLocal.getName(),
originalLocal.getType(),
originalLocal.isFinal(),
methodBody);
newLocalsByOriginalLocal.put(originalLocal, newLocal);
}
ctx.replaceMe(new JLocalRef(x.getSourceInfo(), newLocal));
}
@Override
public void endVisit(JNameOf x, Context ctx) {
HasName node = x.getNode();
boolean pruned;
if (node instanceof JField) {
pruned = isPruned((JField) node);
} else if (node instanceof JMethod) {
pruned = isPruned((JMethod) node);
} else if (node instanceof JReferenceType) {
pruned = !program.typeOracle.isInstantiatedType((JReferenceType) node);
} else {
throw new InternalCompilerException("Unhandled JNameOf node: " + node);
}
if (pruned) {
ctx.replaceMe(program.getLiteralNull());
}
}
@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));
}
@Override
public void endVisit(JBinaryOperation x, Context ctx) {
if (x.getOp() != JBinaryOperator.ASG) {
return;
}
// The LHS of assignments may have been pruned.
lValues.pop();
JExpression lhs = x.getLhs();
if (!(lhs instanceof JVariableRef)) {
return;
}
JVariableRef variableRef = (JVariableRef) lhs;
if (isVariablePruned(variableRef.getTarget())) {
// TODO: better null tracking; we might be missing some NPEs here.
JExpression replacement =
makeReplacementForAssignment(x.getSourceInfo(), variableRef, x.getRhs());
ctx.replaceMe(replacement);
}
}
@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;
}
}
}
/**
* Inline a call to an expression. Returns {@code InlineResult.BLACKLIST} if the method is
* deemed not inlineable regardless of call site; {@code InlineResult.DO_NOT_BLACKLIST}
* otherwise.
*/
private InlineResult tryInlineBody(
JMethodCall x,
Context ctx,
List<JExpression> bodyAsExpressionList,
boolean ignoringReturn) {
if (isTooComplexToInline(bodyAsExpressionList, ignoringReturn)) {
return InlineResult.BLACKLIST;
}
// Do not inline anything that modifies one of its params.
ExpressionAnalyzer targetAnalyzer = new ExpressionAnalyzer();
targetAnalyzer.accept(bodyAsExpressionList);
if (targetAnalyzer.hasAssignmentToParameter()) {
return InlineResult.BLACKLIST;
}
// Make sure the expression we're about to inline doesn't include a call
// to the target method!
RecursionCheckVisitor recursionCheckVisitor = new RecursionCheckVisitor(x.getTarget());
recursionCheckVisitor.accept(bodyAsExpressionList);
if (recursionCheckVisitor.isRecursive()) {
return InlineResult.BLACKLIST;
}
/*
* After this point, it's possible that the method might be inlinable at
* some call sites, depending on its arguments. From here on return 'true'
* as the method might be inlinable elsewhere.
*/
/*
* There are a different number of parameters than args - this is likely a
* result of parameter pruning. Don't consider this call site a candidate.
*
* TODO: would this be possible in the trivial delegation case?
*/
if (x.getTarget().getParams().size() != x.getArgs().size()) {
// Could not inline this call but the method might be inlineable at a different call site.
return InlineResult.DO_NOT_BLACKLIST;
}
// Run the order check. This verifies that all the parameters are
// referenced once and only once, not within a conditionally-executing
// expression and before any tricky target expressions, such as:
// - assignments to any variable
// - expressions that throw exceptions
// - field references
/*
* Ensure correct evaluation order or params relative to each other and to
* other expressions.
*/
OrderVisitor orderVisitor = new OrderVisitor(x.getTarget().getParams());
orderVisitor.accept(bodyAsExpressionList);
switch (orderVisitor.checkResults()) {
case NO_REFERENCES:
/*
* A method that doesn't touch any parameters is trivially inlinable (this
* covers the empty method case)
*/
if (!x.hasSideEffects()) {
markCallsAsSideEffectFree(bodyAsExpressionList);
}
new LocalVariableExtruder(getCurrentMethod()).accept(bodyAsExpressionList);
List<JExpression> expressions = expressionsIncludingArgs(x);
expressions.addAll(bodyAsExpressionList);
ctx.replaceMe(JjsUtils.createOptimizedMultiExpression(ignoringReturn, expressions));
return InlineResult.DO_NOT_BLACKLIST;
case FAILS:
/*
* We can still inline in the case where all of the actual arguments are
* "safe". They must have no side effects, and also have values which
* could not be affected by the execution of any code within the callee.
*/
for (JExpression arg : x.getArgs()) {
ExpressionAnalyzer argAnalyzer = new ExpressionAnalyzer();
argAnalyzer.accept(arg);
if (argAnalyzer.hasAssignment()
|| argAnalyzer.accessesField()
|| argAnalyzer.createsObject()
|| argAnalyzer.canThrowException()) {
/*
* This argument evaluation could affect or be affected by the
* callee so we cannot inline here.
*/
// Could not inline this call but the method is potentially inlineable.
return InlineResult.DO_NOT_BLACKLIST;
}
}
// Fall through!
case CORRECT_ORDER:
default:
if (!x.hasSideEffects()) {
markCallsAsSideEffectFree(bodyAsExpressionList);
}
new LocalVariableExtruder(getCurrentMethod()).accept(bodyAsExpressionList);
// Replace all params in the target expression with the actual arguments.
ParameterReplacer replacer = new ParameterReplacer(x);
replacer.accept(bodyAsExpressionList);
bodyAsExpressionList.add(0, x.getInstance());
bodyAsExpressionList.add(1, createClinitCall(x));
ctx.replaceMe(
JjsUtils.createOptimizedMultiExpression(ignoringReturn, bodyAsExpressionList));
return InlineResult.DO_NOT_BLACKLIST;
}
}
@Override
public void endVisit(JParameterRef x, Context ctx) {
if (x.getParameter() == parameter) {
ctx.replaceMe(cloner.cloneExpression(expression));
}
}
/**
* Replace the current expression with a given multi-expression and mark the method as modified.
* The dead-code elimination pass will optimize this if necessary.
*/
private void replaceWithMulti(Context ctx, JMultiExpression multi) {
ctx.replaceMe(multi);
modifiedMethods.add(currentMethod);
}
// 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);
}
@Override
public void endVisit(JRuntimeTypeReference x, Context ctx) {
if (!program.typeOracle.isInstantiatedType(x.getReferredType())) {
ctx.replaceMe(program.getLiteralNull());
}
}