@Override
public boolean visit(ForStatement node) {
List<Expression> initializers = node.getInitializers();
// The for-loop initializers can either be a single variable declaration
// expression or a list of initializer expressions.
if (initializers.size() == 1 && initializers.get(0) instanceof VariableDeclarationExpression) {
VariableDeclarationExpression decl = (VariableDeclarationExpression) initializers.get(0);
extractVariableDeclarationFragments(
decl.getFragments(), TreeUtil.asStatementList(node).subList(0, 0));
} else {
extractExpressionList(initializers, TreeUtil.asStatementList(node).subList(0, 0), false);
}
Expression expr = node.getExpression();
if (expr != null) {
newExpression(expr);
expr.accept(this);
List<VariableAccess> toExtract = getUnsequencedAccesses();
if (!toExtract.isEmpty()) {
// Convert "if (;cond;)" into "if (;;) { if (!(cond)) break; ...}".
List<Statement> stmtList = TreeUtil.asStatementList(node.getBody()).subList(0, 0);
extractOrderedAccesses(stmtList, currentTopNode, toExtract);
stmtList.add(createLoopTermination(node.getExpression()));
node.setExpression(null);
}
}
extractExpressionList(node.getUpdaters(), TreeUtil.asStatementList(node.getBody()), true);
node.getBody().accept(this);
return false;
}
private void extractVariableDeclarationFragments(
List<VariableDeclarationFragment> fragments, List<Statement> stmtList) {
for (int i = 0; i < fragments.size(); i++) {
VariableDeclarationFragment frag = fragments.get(i);
Expression init = frag.getInitializer();
if (init == null) {
continue;
}
newExpression(init);
init.accept(this);
List<VariableAccess> toExtract = getUnsequencedAccesses();
if (!toExtract.isEmpty()) {
if (i > 0) {
// Extract all fragments before the current one to preserve ordering.
VariableDeclarationStatement newDecl =
new VariableDeclarationStatement(fragments.get(0).copy());
for (int j = 1; j < i; j++) {
newDecl.getFragments().add(fragments.get(j).copy());
}
stmtList.add(newDecl);
fragments.subList(0, i).clear();
}
extractOrderedAccesses(stmtList, currentTopNode, toExtract);
i = 0;
}
}
}
/**
* Returns TRUE of FALSE if 'expr' is a boolean expression and its value is known statically. The
* caller should be careful when replacing this expression as it may have side effects.
*/
private Boolean getKnownValue(Expression expr) {
Object value = expr.getConstantValue();
if (value instanceof Boolean) {
return (Boolean) value;
}
switch (expr.getKind()) {
case BOOLEAN_LITERAL:
return ((BooleanLiteral) expr).booleanValue();
case INFIX_EXPRESSION:
{
InfixExpression infixExpr = (InfixExpression) expr;
InfixExpression.Operator op = infixExpr.getOperator();
if (op == CONDITIONAL_AND || op == CONDITIONAL_OR) {
// We assume that this node has already been visited and pruned so
// if it has a known value, it will be equal to the last operand.
List<Expression> operands = infixExpr.getOperands();
Boolean lastOperand = getKnownValue(operands.get(operands.size() - 1));
if (lastOperand != null && lastOperand.booleanValue() == (op == CONDITIONAL_OR)) {
return lastOperand;
}
}
return null;
}
case PARENTHESIZED_EXPRESSION:
return getKnownValue(((ParenthesizedExpression) expr).getExpression());
default:
return null;
}
}
private boolean needsIdCast(Expression lhs, Expression rhs) {
ITypeBinding lhsType = lhs.getTypeBinding();
ITypeBinding rhsType = rhs.getTypeBinding();
return !lhsType.isPrimitive()
&& !rhsType.isPrimitive()
&& !lhsType.isAssignmentCompatible(rhsType)
&& !rhsType.isAssignmentCompatible(lhsType);
}
@Override
public boolean visit(SuperConstructorInvocation node) {
newExpression(node);
for (Expression arg : node.getArguments()) {
arg.accept(this);
}
extractUnsequenced(node);
return false;
}
@Override
public boolean visit(Assignment node) {
Expression lhs = node.getLeftHandSide();
IVariableBinding lhsVar = TreeUtil.getVariableBinding(lhs);
// Access order is important. If the lhs is a variable, then we must record
// its access after visiting the rhs. Otherwise, visit both sides.
if (lhsVar == null) {
lhs.accept(this);
}
node.getRightHandSide().accept(this);
addVariableAccess(lhsVar, node, true);
return false;
}
@Override
public void endVisit(SuperConstructorInvocation node) {
Expression outerExpression = node.getExpression();
if (outerExpression == null) {
return;
}
node.setExpression(null);
ITypeBinding outerExpressionType = outerExpression.getTypeBinding();
GeneratedMethodBinding binding =
new GeneratedMethodBinding(node.getMethodBinding().getMethodDeclaration());
node.setMethodBinding(binding);
node.getArguments().add(0, outerExpression);
binding.addParameter(0, outerExpressionType);
}
private ITypeBinding getDeclaredType(Expression expr) {
IVariableBinding var = TreeUtil.getVariableBinding(expr);
if (var != null) {
return var.getVariableDeclaration().getType();
}
switch (expr.getKind()) {
case CLASS_INSTANCE_CREATION:
return typeEnv.resolveIOSType("id");
case FUNCTION_INVOCATION:
{
ITypeBinding returnType =
((FunctionInvocation) expr).getFunctionBinding().getReturnType();
if (returnType.isTypeVariable()) {
return typeEnv.resolveIOSType("id");
}
return returnType;
}
case METHOD_INVOCATION:
{
MethodInvocation invocation = (MethodInvocation) expr;
IMethodBinding method = invocation.getMethodBinding();
// Object receiving the message, or null if it's a method in this class.
Expression receiver = invocation.getExpression();
ITypeBinding receiverType =
receiver != null ? receiver.getTypeBinding() : method.getDeclaringClass();
return getDeclaredReturnType(method, receiverType);
}
case PARENTHESIZED_EXPRESSION:
return getDeclaredType(((ParenthesizedExpression) expr).getExpression());
case SUPER_METHOD_INVOCATION:
{
SuperMethodInvocation invocation = (SuperMethodInvocation) expr;
IMethodBinding method = invocation.getMethodBinding();
if (invocation.getQualifier() != null) {
// For a qualified super invocation, the statement generator will look
// up the IMP using instanceMethodForSelector.
if (!method.getReturnType().isPrimitive()) {
return typeEnv.resolveIOSType("id");
} else {
return null;
}
}
return getDeclaredReturnType(
method, TreeUtil.getOwningType(invocation).getTypeBinding().getSuperclass());
}
default:
return null;
}
}
private void visitAndExtract(Expression expr, Statement stmt) {
if (expr != null) {
newExpression(expr);
expr.accept(this);
extractUnsequenced(stmt);
}
}
/**
* Returns an expression containing the side effects of the given expression. The evaluated result
* of the expression may differ from the original.
*/
private Expression extractSideEffects(Expression expr) {
switch (expr.getKind()) {
case INFIX_EXPRESSION:
{
List<Expression> operands = ((InfixExpression) expr).getOperands();
Expression lastOperand = operands.remove(operands.size() - 1);
lastOperand = extractSideEffects(lastOperand);
if (lastOperand != null) {
operands.add(lastOperand);
}
if (operands.size() == 1) {
return operands.remove(0);
}
return TreeUtil.remove(expr);
}
case PARENTHESIZED_EXPRESSION:
{
Expression sideEffects =
extractSideEffects(((ParenthesizedExpression) expr).getExpression());
if (sideEffects != null) {
return ParenthesizedExpression.parenthesize(sideEffects);
}
return null;
}
default:
return null;
}
}
@Override
public void endVisit(CastExpression node) {
ITypeBinding type = node.getType().getTypeBinding();
Expression expr = node.getExpression();
ITypeBinding exprType = expr.getTypeBinding();
// TODO(kirbs): Implement correct conversion of Java 8 intersection types to Objective-C.
if (node.getType().isIntersectionType() && !Options.isJava8Translator()) {
// Technically we can't currently get here, but as we add support and change flags in the
// future this should alert us to implement intersection types.
assert false : "not implemented yet";
}
if (BindingUtil.isFloatingPoint(exprType)) {
assert type.isPrimitive(); // Java wouldn't allow a cast from primitive to non-primitive.
switch (type.getBinaryName().charAt(0)) {
case 'J':
node.replaceWith(rewriteFloatToIntegralCast(type, expr, "JreFpToLong", type));
return;
case 'C':
node.replaceWith(rewriteFloatToIntegralCast(type, expr, "JreFpToChar", type));
return;
case 'B':
case 'S':
case 'I':
node.replaceWith(
rewriteFloatToIntegralCast(type, expr, "JreFpToInt", typeEnv.resolveJavaType("int")));
return;
}
// else fall-through.
}
// Lean on Java's type-checking.
if (!type.isPrimitive() && exprType.isAssignmentCompatible(type.getErasure())) {
node.replaceWith(TreeUtil.remove(expr));
return;
}
FunctionInvocation castCheck = createCastCheck(type, expr);
if (castCheck != null) {
node.setExpression(castCheck);
}
}
private IfStatement createLoopTermination(Expression loopCondition) {
IfStatement newIf = new IfStatement();
newIf.setExpression(
new PrefixExpression(
typeEnv.resolveJavaType("boolean"),
PrefixExpression.Operator.NOT,
ParenthesizedExpression.parenthesize(loopCondition.copy())));
newIf.setThenStatement(new BreakStatement());
return newIf;
}
private void extractExpressionList(
List<Expression> expressions, List<Statement> stmtList, boolean extractModifiedExpression) {
for (int i = 0; i < expressions.size(); i++) {
Expression expr = expressions.get(i);
newExpression(expr);
expr.accept(this);
List<VariableAccess> unsequencedAccesses = getUnsequencedAccesses();
if (!unsequencedAccesses.isEmpty()) {
for (int j = 0; j < i; j++) {
stmtList.add(new ExpressionStatement(expressions.get(j).copy()));
}
expressions.subList(0, i).clear();
extractOrderedAccesses(stmtList, currentTopNode, unsequencedAccesses);
i = 0;
if (extractModifiedExpression) {
stmtList.add(new ExpressionStatement(expressions.get(0).copy()));
expressions.remove(0);
i = -1;
}
}
}
}
@Override
public boolean visit(AssertStatement node) {
Expression expr = node.getExpression();
visitAndExtract(expr, node);
Expression msg = node.getMessage();
if (msg != null) {
newExpression(msg);
msg.accept(this);
List<VariableAccess> toExtract = getUnsequencedAccesses();
if (!toExtract.isEmpty()) {
// If the message expression needs any extraction, then we first extract
// the entire boolean expression to preserve ordering between the two.
IVariableBinding exprVar =
new GeneratedVariableBinding(
"unseq$" + count++, 0, expr.getTypeBinding(), false, false, null, currentMethod);
TreeUtil.insertBefore(
node, new VariableDeclarationStatement(exprVar, node.getExpression().copy()));
node.setExpression(new SimpleName(exprVar));
extractOrderedAccesses(
TreeUtil.asStatementList(node).subList(0, 0), currentTopNode, toExtract);
}
}
return false;
}
// Some native objective-c methods are declared to return NSUInteger.
private boolean returnValueNeedsIntCast(Expression arg) {
IMethodBinding methodBinding = TreeUtil.getMethodBinding(arg);
assert methodBinding != null;
if (arg.getParent() instanceof ExpressionStatement) {
// Avoid "unused return value" warning.
return false;
}
String methodName = nameTable.getMethodSelector(methodBinding);
if (methodName.equals("hash")
&& methodBinding.getReturnType().isEqualTo(typeEnv.resolveJavaType("int"))) {
return true;
}
if (typeEnv.isStringType(methodBinding.getDeclaringClass()) && methodName.equals("length")) {
return true;
}
return false;
}
private boolean needsCast(Expression expr, ITypeBinding expectedType, boolean shouldCastFromId) {
ITypeBinding declaredType = getDeclaredType(expr);
if (declaredType == null) {
return false;
}
ITypeBinding exprType = typeEnv.mapType(expr.getTypeBinding());
declaredType = typeEnv.mapType(declaredType);
if (
// In general we do not need to cast primitive types.
exprType.isPrimitive()
// In most cases we don't need to cast from an id type. However, if the
// expression is being dereferenced then the compiler needs the type
// info.
|| (typeEnv.isIdType(declaredType) && !shouldCastFromId)
// If the declared type can be assigned into the actual type, or the
// expected type, then the compiler already has sufficient type info.
|| typeEnv.isIdType(exprType)
|| typeEnv.isIdType(expectedType)
|| declaredType.isAssignmentCompatible(exprType)
|| declaredType.isAssignmentCompatible(expectedType)) {
return false;
}
return true;
}
private void addCast(Expression expr) {
ITypeBinding exprType = typeEnv.mapType(expr.getTypeBinding());
CastExpression castExpr = new CastExpression(exprType, null);
expr.replaceWith(ParenthesizedExpression.parenthesize(castExpr));
castExpr.setExpression(expr);
}
private void extractConditionalExpression(
List<Statement> stmtList, ConditionalExpression conditional, List<VariableAccess> toExtract) {
Expression condition = conditional.getExpression();
Expression thenExpr = conditional.getThenExpression();
Expression elseExpr = conditional.getElseExpression();
List<VariableAccess> conditionAccesses = Lists.newArrayList();
List<VariableAccess> thenAccesses = Lists.newArrayList();
List<VariableAccess> elseAccesses = Lists.newArrayList();
boolean needsExtraction = false;
for (VariableAccess access : toExtract) {
TreeNode node = access.expression;
while (node.getParent() != conditional) {
node = node.getParent();
}
if (node == condition) {
conditionAccesses.add(access);
} else if (node == thenExpr) {
thenAccesses.add(access);
} else if (node == elseExpr) {
elseAccesses.add(access);
} else {
throw new AssertionError();
}
if (node != condition && access.isModification) {
// We only need to extract an if-statement if there is a modification
// that executes conditionally.
needsExtraction = true;
}
}
extractOrderedAccesses(stmtList, condition, conditionAccesses);
// The recursive call might replace the condition child.
condition = conditional.getExpression();
if (needsExtraction) {
IVariableBinding resultVar =
new GeneratedVariableBinding(
"unseq$" + count++,
0,
conditional.getTypeBinding(),
false,
false,
null,
currentMethod);
conditional.replaceWith(new SimpleName(resultVar));
stmtList.add(new VariableDeclarationStatement(resultVar, null));
IfStatement newIf = new IfStatement();
newIf.setExpression(condition.copy());
stmtList.add(newIf);
Block thenBlock = new Block();
newIf.setThenStatement(thenBlock);
List<Statement> thenStmts = thenBlock.getStatements();
extractOrderedAccesses(thenStmts, thenExpr, thenAccesses);
// The recursive call might replace the then expression child.
thenExpr = conditional.getThenExpression();
thenStmts.add(
new ExpressionStatement(new Assignment(new SimpleName(resultVar), thenExpr.copy())));
Block elseBlock = new Block();
newIf.setElseStatement(elseBlock);
List<Statement> elseStmts = elseBlock.getStatements();
extractOrderedAccesses(elseStmts, elseExpr, elseAccesses);
// The recursive call might replace the else expression child.
elseExpr = conditional.getElseExpression();
elseStmts.add(
new ExpressionStatement(new Assignment(new SimpleName(resultVar), elseExpr.copy())));
} else {
extractOrderedAccesses(stmtList, thenExpr, thenAccesses);
extractOrderedAccesses(stmtList, elseExpr, elseAccesses);
}
}
