private static void CgAssignStat(FuncInfo fi, AssignStat node)
{
var exps = RemoveTailNil(node.ExpList);
var nExps = exps.Count;
var nVars = node.VarList.Count;
var tRegs = new int[nVars];
var kRegs = new int[nVars];
var vRegs = new int[nVars];
var oldRegs = fi.UsedRegs;
for (var i = 0; i < node.VarList.Count; i++)
{
var exp = node.VarList[i];
if (exp is TableAccessExp tableAccessExp)
{
tRegs[i] = fi.AllocReg();
CgExp(fi, tableAccessExp.PrefixExp, tRegs[i], 1);
kRegs[i] = fi.AllocReg();
CgExp(fi, tableAccessExp.KeyExp, kRegs[i], 1);
}
else if (exp is NameExp nameExp)
{
var name = nameExp.Name;
if (fi.SlotOfLocVar(name) < 0 && fi.IndexOfUpval(name) < 0)
{
kRegs[i] = -1;
fi.IndexOfConstant(name, out var constIdx);
if (constIdx > 0xff)
{
kRegs[i] = fi.AllocReg();
}
}
}
}
for (var i = 0; i < nVars; i++)
{
vRegs[i] = fi.UsedRegs + i;
}
if (nExps >= nVars)
{
for (var i = 0; i < exps.Count; i++)
{
var exp = exps[i];
var a = fi.AllocReg();
if (i >= nVars && i == nExps - 1 && IsVarargOrFuncCall(exp))
{
CgExp(fi, exp, a, 0);
}
else
{
CgExp(fi, exp, a, 1);
}
}
}
else
{
var multRet = false;
for (var i = 0; i < exps.Count; i++)
{
var exp = exps[i];
var a = fi.AllocReg();
if (i == nExps - 1 && IsVarargOrFuncCall(exp))
{
multRet = true;
var n = nVars - nExps + 1;
CgExp(fi, exp, a, n);
fi.AllocRegs(n - 1);
}
else
{
CgExp(fi, exp, a, 1);
}
}
if (!multRet)
{
var n = nVars - nExps;
var a = fi.AllocRegs(n);
fi.EmitLoadNil(a, n);
}
}
for (var i = 0; i < node.VarList.Count; i++)
{
var exp = node.VarList[i];
if (exp is NameExp nameExp)
{
var varName = nameExp.Name;
var a = fi.SlotOfLocVar(varName);
if (a >= 0)
{
fi.EmitMove(a, vRegs[i]);
}
else
{
var b = fi.IndexOfUpval(varName);
if (b >= 0)
{
fi.EmitSetUpval(vRegs[i], b);
}
else
{
a = fi.SlotOfLocVar("_ENV");
if (a >= 0)
{
if (kRegs[i] < 0)
{
fi.IndexOfConstant(varName, out var constIdx);
b = 0x100 + constIdx;
fi.EmitSetTable(a, b, vRegs[i]);
}
else
{
fi.EmitSetTable(a, kRegs[i], vRegs[i]);
}
}
else
{
a = fi.IndexOfUpval("_ENV");
if (kRegs[i] < 0)
{
fi.IndexOfConstant(varName, out var idx);
b = 0x100 + idx;
fi.EmitSetTabUp(a, b, vRegs[i]);
}
else
{
fi.EmitSetTable(a, kRegs[i], vRegs[i]);
}
}
}
}
}
else
{
fi.EmitSetTable(tRegs[i], kRegs[i], vRegs[i]);
}
}
fi.UsedRegs = oldRegs;
}
private static void CgExp(FuncInfo fi, Exp node, int a, int n)
{
switch (node)
{
case NilExp _:
fi.EmitLoadNil(a, n);
break;
case FalseExp _:
fi.EmitLoadBool(a, 0, 0);
break;
case TrueExp _:
fi.EmitLoadBool(a, 1, 0);
break;
case IntegerExp integerExp:
fi.EmitLoadK(a, integerExp.Val);
break;
case FloatExp floatExp:
fi.EmitLoadK(a, floatExp.Val);
break;
case StringExp stringExp:
fi.EmitLoadK(a, stringExp.Str);
break;
case ParensExp parensExp:
CgExp(fi, parensExp.Exp, a, 1);
break;
case VarargExp varargExp:
CgVarargExp(fi, varargExp, a, n);
break;
case FuncDefExp funcDefExp:
CgFuncDefExp(fi, funcDefExp, a);
break;
case TableConstructorExp tableConstructorExp:
CgTableConstructorExp(fi, tableConstructorExp, a);
break;
case UnopExp unopExp:
CgUnopExp(fi, unopExp, a);
break;
case BinopExp binopExp:
CgBinopExp(fi, binopExp, a);
break;
case ConcatExp concatExp:
CgConcatExp(fi, concatExp, a);
break;
case NameExp nameExp:
CgNameExp(fi, nameExp, a);
break;
case TableAccessExp tableAccessExp:
CgTableAccessExp(fi, tableAccessExp, a);
break;
case FuncCallExp funcCallExp:
CgFuncCallExp(fi, funcCallExp, a, n);
break;
}
}
private static void CgLocalVarDeclStat(FuncInfo fi, LocalVarDeclStat node)
{
var exps = RemoveTailNil(node.ExpList);
var nExps = exps.Count;
var nNames = node.NameList.Count;
var oldRegs = fi.UsedRegs;
if (nExps == nNames)
{
foreach (var exp in exps)
{
var a = fi.AllocReg();
CgExp(fi, exp, a, 1);
}
}
else if (nExps > nNames)
{
for (var i = 0; i < exps.Count; i++)
{
var exp = exps[i];
var a = fi.AllocReg();
if (i == nExps - 1 && IsVarargOrFuncCall(exp))
{
CgExp(fi, exp, a, 0);
}
else
{
CgExp(fi, exp, a, 1);
}
}
}
else
{
var multRet = false;
for (var i = 0; i < exps.Count; i++)
{
var exp = exps[i];
var a = fi.AllocReg();
if (i == nExps - 1 && IsVarargOrFuncCall(exp))
{
multRet = true;
var n = nNames - nExps + 1;
CgExp(fi, exp, a, n);
fi.AllocRegs(n - 1);
}
else
{
CgExp(fi, exp, a, 1);
}
}
if (!multRet)
{
var n = nNames - nExps;
var a = fi.AllocRegs(n);
fi.EmitLoadNil(a, n);
}
}
fi.UsedRegs = oldRegs;
foreach (var name in node.NameList)
{
fi.AddLocVar(name);
}
}