public static IEnumerable <ExprVar> V(ICode ast)
{
var v = new VisitorFindVars();
v.Visit(ast);
return(v.vars);
}
private void AddKnownTrue(Expr e)
{
if (VisitorFindVars.V(e).Any())
{
this.knownTrue.Peek().Add(e);
}
}
protected override ICode VisitIf(StmtIf s)
{
var ctx = s.Ctx;
var condition = (Expr)this.Visit(s.Condition);
this.stack.Push(new List <ExprVar>());
var then = (Stmt)this.Visit(s.Then);
var thenDA = this.stack.Pop();
this.stack.Push(new List <ExprVar>());
var @else = (Stmt)this.Visit(s.Else);
var elseDA = this.stack.Pop();
var intersection = thenDA.Intersect(elseDA, (IEqualityComparer <ExprVar>) this.phiComparer).ToArray();
this.stack.Peek().AddRange(intersection);
var conditionVars = VisitorFindVars.V(condition);
var needAssigning = conditionVars.Except(this.stack.SelectMany(x => x), (IEqualityComparer <ExprVar>) this.phiComparer).ToArray();
if (needAssigning.Any())
{
var replacements = needAssigning.Select(x => {
var newExpr = ctx.Local(x.Type);
var phi = new ExprVarPhi(ctx)
{
Exprs = new[] { x, newExpr }
};
return(new { orgExpr = x, newExpr, phi });
}).ToArray();
foreach (var replace in replacements)
{
this.stack.Peek().Add(replace.newExpr);
this.stack.Peek().Add(replace.phi);
condition = (Expr)VisitorReplace.V(condition, replace.orgExpr, replace.phi);
}
this.ensureAssigned.Add(s, replacements.Select(x => x.newExpr).ToArray());
}
if (condition != s.Condition || then != s.Then || @else != s.Else)
{
var newS = new StmtIf(ctx, condition, then, @else);
this.stmtMap.Add(newS, s);
return(newS);
}
else
{
return(s);
}
}
protected override ICode VisitDoLoop(StmtDoLoop s)
{
var ctx = s.Ctx;
var body = (Stmt)this.Visit(s.Body);
var @while = (Expr)this.Visit(s.While);
var conditionVars = VisitorFindVars.V(@while);
var needAssigning = conditionVars.Except(this.stack.SelectMany(x => x), (IEqualityComparer <ExprVar>) this.phiComparer).ToArray();
if (needAssigning.Any())
{
var replacements = needAssigning.Select(x => {
var newExpr = ctx.Local(x.Type);
var phi = new ExprVarPhi(ctx)
{
Exprs = new[] { x, newExpr }
};
return(new { orgExpr = x, newExpr, phi });
}).ToArray();
foreach (var replace in replacements)
{
this.stack.Peek().Add(replace.newExpr);
this.stack.Peek().Add(replace.phi);
@while = (Expr)VisitorReplace.V(@while, replace.orgExpr, replace.phi);
}
var assignmentStmts = replacements
.Select(x => new StmtAssignment(ctx, x.newExpr, new ExprDefaultValue(ctx, x.newExpr.Type)))
.ToArray();
body = new StmtBlock(ctx, assignmentStmts.Concat(body));
}
if (body != s.Body || @while != s.While)
{
return(new StmtDoLoop(ctx, body, @while));
}
else
{
return(s);
}
}
private void AddKnownTrue(IEnumerable <Expr> es)
{
this.knownTrue.Peek().AddRange(es.Where(x => VisitorFindVars.V(x).Any()));
}
public static IEnumerable<ExprVar> V(ICode ast) {
var v = new VisitorFindVars();
v.Visit(ast);
return v.vars;
}