private MidExp SimplifyLabelExpImpl(
MidLabelExp labelExp,
MidLetExp letExp,
SimplifyEnv env)
{
// As long as the label doesn't occur in the
// bound expression, we can move it outside
// of the label's bounds.
if (!UsesLabel(letExp.Exp, labelExp.Label))
{
MidExp result = new MidLetExp(
letExp.Range,
letExp.Var,
letExp.Exp,
new MidLabelExp(
labelExp.Range,
labelExp.Label,
letExp.Body,
labelExp.Type));
result = SimplifyExp(result, env);
return(result);
}
return(labelExp);
}
private MidExp SimplifyExpImpl(MidLetExp exp, SimplifyEnv env)
{
if (exp.Exp is MidVal)
{
// The variable is just being bound to a simple
// value, so substitute it away:
var innerEnv = new SimplifyEnv(env);
innerEnv.Insert(exp.Var, (MidVal)exp.Exp);
return(SimplifyExp(exp.Body, innerEnv));
}
if (exp.Exp is MidBreakExp)
{
// Well, we can't possibly get to the rest of the
// expression, right?
return(exp.Exp);
}
if (exp.Body is MidVarRef)
{
var midVarRef = (MidVarRef)exp.Body;
if (midVarRef.Var == exp.Var)
{
return(exp.Exp);
}
}
if (exp.Exp is MidPath)
{
var midPath = (MidPath)exp.Exp;
// Try to substitute this path into
// any down-stream field references...
var midLet = exp;
while (midLet != null)
{
midLet.Exp = TryFoldPath(exp.Var, midLet.Exp, midPath);
midLet.Body = TryFoldPath(exp.Var, midLet.Body, midPath);
midLet = midLet.Body as MidLetExp;
}
}
if (!UsesVar(exp.Body, exp.Var) && !MightHaveSideEffects(exp.Exp))
{
// \todo: Should be able to DCE the let expression away,
// but to do that we need to be sure it doesn't have
// any side-effects... :(
return(exp.Body);
}
return(exp);
}
private static void DumpExpImpl(
MidLetExp let,
Span span)
{
span.Write("let {0} = ", let.Var.Name);
let.Exp.Dump(span.IndentSpan());
span.WriteLine(";");
let.Body.Dump(span);
}
private EmitValHLSL EmitExpImpl(MidLetExp let, Span span)
{
var initVal = EmitExp(let.Exp, span);
#if ALWAYSBIND
// \todo: Just use the type from init?
var varType = EmitType(let.Var.Type);
var var = varType.CreateVal(
_shared.GenerateName("_var"));
_varVals[let.Var] = var;
DeclareAndInitLocal(
var,
initVal,
span);
#else
_varVals[let.Var] = initVal;
#endif
return EmitExp(let.Body, span);
}
public void PreEmitExpImpl(
MidLetExp exp,
Span span)
{
PreEmitExp(exp.Exp, span);
PreEmitExp(exp.Body, span);
}
private void TransformChildrenImpl(
MidLetExp let)
{
let.Exp = Transform(let.Exp);
let.Body = Transform(let.Body);
}
private MidExp SimplifyLabelExpImpl(
MidLabelExp labelExp,
MidLetExp letExp,
SimplifyEnv env)
{
// As long as the label doesn't occur in the
// bound expression, we can move it outside
// of the label's bounds.
if (!UsesLabel(letExp.Exp, labelExp.Label))
{
MidExp result = new MidLetExp(
letExp.Range,
letExp.Var,
letExp.Exp,
new MidLabelExp(
labelExp.Range,
labelExp.Label,
letExp.Body,
labelExp.Type));
result = SimplifyExp(result, env);
return result;
}
return labelExp;
}
private MidExp SimplifyExpImpl(MidLetExp exp, SimplifyEnv env)
{
if (exp.Exp is MidVal)
{
// The variable is just being bound to a simple
// value, so substitute it away:
var innerEnv = new SimplifyEnv(env);
innerEnv.Insert(exp.Var, (MidVal) exp.Exp);
return SimplifyExp(exp.Body, innerEnv);
}
if (exp.Exp is MidBreakExp)
{
// Well, we can't possibly get to the rest of the
// expression, right?
return exp.Exp;
}
if (exp.Body is MidVarRef)
{
var midVarRef = (MidVarRef)exp.Body;
if (midVarRef.Var == exp.Var)
return exp.Exp;
}
if (exp.Exp is MidPath)
{
var midPath = (MidPath)exp.Exp;
// Try to substitute this path into
// any down-stream field references...
var midLet = exp;
while (midLet != null)
{
midLet.Exp = TryFoldPath(exp.Var, midLet.Exp, midPath);
midLet.Body = TryFoldPath(exp.Var, midLet.Body, midPath);
midLet = midLet.Body as MidLetExp;
}
}
if (!UsesVar(exp.Body, exp.Var) && !MightHaveSideEffects(exp.Exp))
{
// \todo: Should be able to DCE the let expression away,
// but to do that we need to be sure it doesn't have
// any side-effects... :(
return exp.Body;
}
return exp;
}
private void TransformChildrenImpl(
MidLetExp let)
{
let.Exp = Transform(let.Exp);
let.Body = Transform(let.Body);
}