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;
}
@Override
public boolean visit(IfStatement node) {
visitAndExtract(node.getExpression(), node);
node.getThenStatement().accept(this);
Statement elseStmt = node.getElseStatement();
if (elseStmt != null) {
elseStmt.accept(this);
}
return false;
}
@Override
public void endVisit(IfStatement node) {
Expression expr = node.getExpression();
Boolean value = getKnownValue(expr);
if (value != null) {
Statement sideEffects = getSideEffects(expr);
if (sideEffects != null) {
TreeUtil.insertBefore(node, sideEffects);
}
if (value) {
node.replaceWith(TreeUtil.remove(node.getThenStatement()));
} else if (node.getElseStatement() != null) {
node.replaceWith(TreeUtil.remove(node.getElseStatement()));
} else {
node.remove();
}
}
}
private void extractInfixConditional(
List<Statement> stmtList, InfixExpression conditional, List<VariableAccess> toExtract) {
InfixExpression.Operator op = conditional.getOperator();
List<Expression> branches = conditional.getOperands();
int lastIfExtractIdx = 0;
IVariableBinding conditionalVar = null;
int lastExtracted = 0;
Expression lastBranch = null;
for (int i = 0; i < toExtract.size(); i++) {
VariableAccess access = toExtract.get(i);
TreeNode node = access.expression;
while (node.getParent() != conditional) {
node = node.getParent();
}
assert node instanceof Expression;
Expression branch = (Expression) node;
// Extract all accesses from the previous branch.
if (lastBranch != null && branch != lastBranch) {
extractOrderedAccesses(stmtList, lastBranch, toExtract.subList(lastExtracted, i));
lastExtracted = i;
}
lastBranch = branch;
// If there's a new modification in a new branch, then we extract an if-statement.
if (access.isModification && branch != branches.get(lastIfExtractIdx)) {
ITypeBinding boolType = typeEnv.resolveJavaType("boolean");
if (conditionalVar == null) {
conditionalVar =
new GeneratedVariableBinding(
"unseq$" + count++, 0, boolType, false, false, null, currentMethod);
conditional.replaceWith(new SimpleName(conditionalVar));
stmtList.add(new VariableDeclarationStatement(conditionalVar, null));
}
List<Expression> subBranches = branches.subList(lastIfExtractIdx, branches.indexOf(branch));
IfStatement newIf = new IfStatement();
Expression ifExpr =
new Assignment(
new SimpleName(conditionalVar), conditionalFromSubBranches(subBranches, op));
if (op == InfixExpression.Operator.CONDITIONAL_OR) {
ifExpr =
new PrefixExpression(
boolType,
PrefixExpression.Operator.NOT,
ParenthesizedExpression.parenthesize(ifExpr));
}
newIf.setExpression(ifExpr);
stmtList.add(newIf);
Block thenBlock = new Block();
stmtList = thenBlock.getStatements();
newIf.setThenStatement(thenBlock);
lastIfExtractIdx = branches.indexOf(branch);
}
}
extractOrderedAccesses(
stmtList, lastBranch, toExtract.subList(lastExtracted, toExtract.size()));
if (conditionalVar != null) {
List<Expression> remainingBranches = Lists.newArrayList();
remainingBranches.add(new SimpleName(conditionalVar));
remainingBranches.addAll(branches.subList(lastIfExtractIdx, branches.size()));
stmtList.add(
new ExpressionStatement(
new Assignment(
new SimpleName(conditionalVar),
conditionalFromSubBranches(remainingBranches, op))));
}
}
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);
}
}