/// <summary>
/// Visits the specified addition.
/// </summary>
/// <param name="addition">The addition.</param>
/// <returns></returns>
protected virtual IExpression DeepCopy(Addition addition)
{
return this.DeepCopy((BinaryOperation)addition);
}
private Expression ParseAddition(OperationCode currentOpcode)
{
Addition addition = new Addition();
addition.CheckOverflow = currentOpcode != OperationCode.Add;
if (currentOpcode == OperationCode.Add_Ovf_Un) {
addition.TreatOperandsAsUnsignedIntegers = true; //force use of unsigned addition, even for cases where the operands are expressions that result in signed values
return this.ParseUnsignedBinaryOperation(addition);
} else
return this.ParseBinaryOperation(addition);
}
/// <summary>
/// Visits the specified addition.
/// </summary>
/// <param name="addition">The addition.</param>
public override void Visit(IAddition addition)
{
Addition/*?*/ mutableAddition = new Addition(addition);
this.resultExpression = this.myCodeCopier.DeepCopy(mutableAddition);
}
/// <summary>
/// For a string field, s, the source expression e.s += ""
/// turns into a specific pattern.
/// That pattern here looks like:
/// i: push e
/// i+1: push dup.s
/// i+2: (!= dup (default_value string)) ? goto L2 : empty
/// i+3: L1
/// i+4: pop
/// i+5: push ""
/// i+6: L2
/// i+7: pop.s = pop
/// </summary>
private bool ReplacePlusAssignForStringPattern(BlockStatement b) {
Contract.Requires(b != null);
bool replacedPattern = false;
var statements = b.Statements;
for (int i = 0; i < statements.Count - 7; i++) {
var push1 = statements[i] as PushStatement;
if (push1 == null) continue;
var push2 = statements[i + 1] as PushStatement;
if (push2 == null) continue;
var boundExpression = push2.ValueToPush as IBoundExpression;
if (boundExpression == null) continue;
var dupValue = boundExpression.Instance as IDupValue;
if (dupValue == null) continue;
var field = boundExpression.Definition as IFieldReference;
if (field == null) continue;
var conditionalStatement = statements[i + 2] as IConditionalStatement;
if (conditionalStatement == null) continue;
var notEquality = conditionalStatement.Condition as INotEquality;
if (notEquality == null) continue;
var gotoStatement = conditionalStatement.TrueBranch as IGotoStatement;
if (gotoStatement == null) continue;
var branchTarget = gotoStatement.TargetStatement;
var emptyStatement = conditionalStatement.FalseBranch as IEmptyStatement;
if (emptyStatement == null) continue;
var labeledStatement = statements[i + 3] as ILabeledStatement;
if (labeledStatement == null) continue;
var popStatement = statements[i + 4] as IExpressionStatement;
if (popStatement == null) continue;
if (!(popStatement.Expression is IPopValue)) continue;
var pushEmptyString = statements[i + 5] as IPushStatement;
if (pushEmptyString == null) continue;
var emptyString = pushEmptyString.ValueToPush as ICompileTimeConstant;
if (emptyString == null) continue;
if (emptyString.Type.TypeCode != PrimitiveTypeCode.String) continue;
if ((string)emptyString.Value != "") continue;
labeledStatement = statements[i + 6] as ILabeledStatement;
if (labeledStatement == null) continue;
if (labeledStatement.Label != branchTarget.Label) continue;
var assignStatement = statements[i + 7] as IExpressionStatement;
if (assignStatement == null) continue;
var assignment = assignStatement.Expression as IAssignment;
if (assignment == null) continue;
if (!(assignment.Source is IPopValue)) continue;
if (!(assignment.Target.Instance is IPopValue)) continue;
// REVIEW: should the definition of the target be checked to be the same as "field"? If so, how?
var plusEqual = new Addition() {
LeftOperand = new TargetExpression() {
Definition = assignment.Target.Definition,
Instance = push1.ValueToPush,
},
RightOperand = emptyString,
ResultIsUnmodifiedLeftOperand = false,
Type = assignment.Type,
};
statements[i] = new ExpressionStatement() {
Expression = plusEqual,
Locations = new List<ILocation>(push1.Locations),
};
statements.RemoveRange(i + 1, 7);
replacedPattern = true;
}
return replacedPattern;
}
/// <summary>
/// Visits the specified addition.
/// </summary>
/// <param name="addition">The addition.</param>
/// <returns></returns>
public virtual IExpression Visit(Addition addition)
{
return this.Visit((BinaryOperation)addition);
}
/// <summary>
/// Rewrites the children of the given addition.
/// </summary>
/// <param name="addition"></param>
public virtual void RewriteChildren(Addition addition)
{
this.RewriteChildren((BinaryOperation)addition);
}
/// <summary>
/// Visits the specified addition.
/// </summary>
/// <param name="addition">The addition.</param>
public override void Visit(IAddition addition)
{
Addition/*?*/ mutableAddition = addition as Addition;
if (alwaysMakeACopy || mutableAddition == null) mutableAddition = new Addition(addition);
this.resultExpression = this.myCodeMutator.Visit(mutableAddition);
}