public static IEnumerable <Expr> Get(ICode ast, Expr.Special specials)
{
var v = new VisitorFindSpecials(specials);
v.Visit(ast);
return(v.results);
}
protected override ICode VisitAssignment(StmtAssignment s)
{
var aInfo = this.GetAInfo(s.Target);
aInfo.assignment = s;
if (s.Target.ExprType != Expr.NodeType.VarLocal || s.Target.Type.IsByReference ||
VisitorFindSpecials.Any(s.Expr, Expr.Special.PossibleSideEffects))
{
aInfo.mustKeep = true;
}
this.Visit(s.Target);
this.Visit(s.Expr);
return(s);
}
// TODO: Restrict movement across try/catch/finally borders
public static ICode V(ICode ast)
{
var v = new VisitorSsaCopyPropagation();
var ast2 = v.Visit(ast);
var alreadyReplaced = new Dictionary <Expr, Expr>();
foreach (var a in v.assignments.Values)
{
if (a.mustKeep)
{
continue;
}
if (a.assignment == null)
{
continue;
}
if (a.count == 1)
{
if (!VisitorFindSpecials.Any(a.assignment, Expr.Special.PossibleSideEffects))
{
ast2 = VisitorReplace.V(ast2, a.assignment, null);
}
}
else if (a.count == 2 /*||
* (IsSimple(alreadyReplaced.ValueOrDefault(a.assignment.Expr, a.assignment.Expr)) && !a.assignment.Expr.Type.IsNonPrimitiveValueType())*/)
{
var updater = new Updater(a.assignment.Target);
ast2 = updater.Visit(ast2);
foreach (var replaced in updater.Replaced)
{
alreadyReplaced[replaced.Item1] = replaced.Item2;
}
}
}
return(ast2);
}
public static IEnumerable<Expr> Get(ICode ast, Expr.Special specials) {
var v = new VisitorFindSpecials(specials);
v.Visit(ast);
return v.results;
}