/// <summary>
/// 遍历Ast树，生成四元式列表
/// </summary>
/// <param name="ast">Ast树</param>
/// <param name="varTable">变量表</param>
/// <returns></returns>
public static List<FourExp> Translate(Ast ast, VarTable varTable)
{
List<FourExp> fourExpList = new List<FourExp>();
LabelStack labelStack = new LabelStack();
foreach (Statement s in ast.Statements)
{
s.Translate(varTable, labelStack, fourExpList);
}
return fourExpList;
}
public override string GetValue(VarTable varTable, LabelStack labelStack, List<FourExp> fourExpList)
{
string returnValue = "";
string label, t1, t2, var;
switch (this.op.Type)
{
case OperatorType.not: //非
label = labelStack.NewLabel();
var = expression.GetValue(varTable, labelStack, fourExpList);
fourExpList.Add(FourExpFac.GenJe(var, 0 + "", label));
t1 = varTable.NewTemp(VariableType.BOOL);
fourExpList.Add(FourExpFac.GenMov(1 + "", t1));
var = t1;
fourExpList.Add(FourExpFac.GenLabel(label));
t2 = varTable.NewTemp(VariableType.BOOL);
fourExpList.Add(FourExpFac.GenNot(t1, t2));
returnValue = t2;
break;
case OperatorType.selfaddhead: //自增前置
var = expression.GetValue(varTable, labelStack, fourExpList);
fourExpList.Add(FourExpFac.GenAdd(var, 1 + "", var));
returnValue = var;
break;
case OperatorType.selfsubhead: //自减前置
var = expression.GetValue(varTable, labelStack, fourExpList);
fourExpList.Add(FourExpFac.GenSub(var, 1 + "", var));
returnValue = var;
break;
case OperatorType.selfaddtail: //自增后置
var = expression.GetValue(varTable, labelStack, fourExpList);
t1 = varTable.NewTemp(var);
fourExpList.Add(FourExpFac.GenAdd(var, 1 + "", var));
returnValue = t1;
break;
case OperatorType.selfsubtail: //自减后置
var = expression.GetValue(varTable, labelStack, fourExpList);
t1 = varTable.NewTemp(var);
fourExpList.Add(FourExpFac.GenSub(var, 1 + "", var));
returnValue = t1;
break;
case OperatorType.bitnot: //按位非
var = expression.GetValue(varTable, labelStack, fourExpList);
t1 = varTable.NewTemp(var);
fourExpList.Add(FourExpFac.GenNot(var, t1));
returnValue = t1;
break;
case OperatorType.neg: //取反
var = expression.GetValue(varTable, labelStack, fourExpList);
t1 = varTable.NewTemp(var);
fourExpList.Add(FourExpFac.GenNeg(var, t1));
returnValue = t1;
break;
}
return returnValue;
}
public override void Translate(VarTable varTable, LabelStack labelStack, List<FourExp> fourExpList)
{
}
public override string GetValue(VarTable varTable, LabelStack labelStack, List<FourExp> fourExpList)
{
string returnValue = "";
//加、减、乘、除、按位与、按位或
if (this.op.Type == OperatorType.add || this.op.Type == OperatorType.sub || this.op.Type == OperatorType.mul || this.op.Type == OperatorType.div || this.op.Type == OperatorType.bitand || this.op.Type == OperatorType.bitor)
{
string arg1 = expression1.GetValue(varTable, labelStack, fourExpList);
string arg2 = expression2.GetValue(varTable, labelStack, fourExpList);
string t = varTable.NewTemp(arg1, arg2);
switch (this.op.Type)
{
case OperatorType.add: //+
fourExpList.Add(FourExpFac.GenAdd(arg1, arg2, t));
break;
case OperatorType.sub: //-
fourExpList.Add(FourExpFac.GenSub(arg1, arg2, t));
break;
case OperatorType.mul: //*
fourExpList.Add(FourExpFac.GenMul(arg1, arg2, t));
break;
case OperatorType.div: ///
fourExpList.Add(FourExpFac.GenDiv(arg1, arg2, t));
break;
case OperatorType.bitand: //按位与
fourExpList.Add(FourExpFac.GenAnd(arg1, arg2, t));
break;
case OperatorType.bitor: //按位或
fourExpList.Add(FourExpFac.GenOr(arg1, arg2, t));
break;
default:
break;
}
returnValue = t;
}
//与、或
else if (this.op.Type == OperatorType.and || this.op.Type == OperatorType.or)
{
string label1 = labelStack.NewLabel();
string arg1 = expression1.GetValue(varTable, labelStack, fourExpList);
fourExpList.Add(FourExpFac.GenJe(arg1, 0 + "", label1));
string t1 = varTable.NewTemp(VariableType.BOOL);
fourExpList.Add(FourExpFac.GenMov(1 + "", t1));
arg1 = t1;
fourExpList.Add(FourExpFac.GenLabel(label1));
string label2 = labelStack.NewLabel();
string arg2 = expression2.GetValue(varTable, labelStack, fourExpList);
fourExpList.Add(FourExpFac.GenJe(arg2, 0 + "", label2));
string t2 = varTable.NewTemp(VariableType.BOOL);
fourExpList.Add(FourExpFac.GenMov(1 + "", t2));
arg2 = t2;
fourExpList.Add(FourExpFac.GenLabel(label2));
string t3 = varTable.NewTemp(VariableType.BOOL);
switch (this.op.Type)
{
case OperatorType.and: //与
fourExpList.Add(FourExpFac.GenAnd(arg1, arg2, t3));
break;
case OperatorType.or: //或
fourExpList.Add(FourExpFac.GenOr(arg1, arg2, t3));
break;
}
returnValue = t3;
}
//左移、右移
else if (this.op.Type == OperatorType.leftmove || this.op.Type == OperatorType.rightmove)
{
string arg1 = expression1.GetValue(varTable, labelStack, fourExpList);
string arg2 = expression2.GetValue(varTable, labelStack, fourExpList);
string t = varTable.NewTemp(arg1);
switch (this.op.Type)
{
case OperatorType.leftmove: //左移
fourExpList.Add(FourExpFac.GenLeftshift(arg1, arg2, t));
break;
case OperatorType.rightmove: //右移
fourExpList.Add(FourExpFac.GenRightshift(arg1, arg2, t));
break;
default:
break;
}
returnValue = t;
}
//小于、小于等于、大于、大于等于、等于、不等于
else if (this.op.Type == OperatorType.less || this.op.Type == OperatorType.lessequal || this.op.Type == OperatorType.greater || this.op.Type == OperatorType.greatereuqal || this.op.Type == OperatorType.equal || this.op.Type == OperatorType.notequal)
{
string label1 = labelStack.NewLabel();
string label2 = labelStack.NewLabel();
string t = varTable.NewTemp(VariableType.BOOL);
string arg1 = expression1.GetValue(varTable, labelStack, fourExpList);
string arg2 = expression2.GetValue(varTable, labelStack, fourExpList);
switch (this.op.Type)
{
case OperatorType.less: //<
fourExpList.Add(FourExpFac.GenJl(arg1, arg2, label1));
break;
case OperatorType.lessequal: //<=
fourExpList.Add(FourExpFac.GenJle(arg1, arg2, label1));
break;
case OperatorType.greater: //>
fourExpList.Add(FourExpFac.GenJg(arg1, arg2, label1));
break;
case OperatorType.greatereuqal: //>=
fourExpList.Add(FourExpFac.GenJge(arg1, arg2, label1));
break;
case OperatorType.equal: //==
fourExpList.Add(FourExpFac.GenJe(arg1, arg2, label1));
break;
case OperatorType.notequal: //!=
fourExpList.Add(FourExpFac.GenJne(arg1, arg2, label1));
break;
default:
//
break;
}
fourExpList.Add(FourExpFac.GenMov(0 + "", t));
fourExpList.Add(FourExpFac.GenJmp(label2));
fourExpList.Add(FourExpFac.GenLabel(label1));
fourExpList.Add(FourExpFac.GenMov(1 + "", t));
fourExpList.Add(FourExpFac.GenLabel(label2));
returnValue = t;
}
else
{
//错误处理
}
return returnValue;
}
public override string GetValue(VarTable varTable, LabelStack labelStack, List<FourExp> fourExpList)
{
return this.value.ToString();
}
public override string GetValue(VarTable varTable, LabelStack labelStack, List<FourExp> fourExpList)
{
return "";
}
public override void Translate(VarTable varTable, LabelStack labelStack, List<FourExp> fourExpList)
{
if (statement1 == null)
{
string label = labelStack.NewLabel();
string condition = expression.GetValue(varTable, labelStack, fourExpList);
fourExpList.Add(FourExpFac.GenJe(condition, 0+"", label));
statement1.Translate(varTable, labelStack, fourExpList);
fourExpList.Add(FourExpFac.GenLabel(label));
}
else
{
string label1 = labelStack.NewLabel();
string label2 = labelStack.NewLabel();
string condition = expression.GetValue(varTable, labelStack, fourExpList);
fourExpList.Add(FourExpFac.GenJe(condition, 0 + "", label1));
statement1.Translate(varTable, labelStack, fourExpList);
fourExpList.Add(FourExpFac.GenJmp(label2));
fourExpList.Add(FourExpFac.GenLabel(label1));
statement2.Translate(varTable, labelStack, fourExpList);
fourExpList.Add(FourExpFac.GenLabel(label2));
}
}
public override void Translate(VarTable varTable, LabelStack labelStack, List<FourExp> fourExpList)
{
int value = 0;
varTable.Add(this.name, this.type, value);
}
public virtual string GetValue(VarTable varTable, LabelStack labelStack, List<FourExp> fourExpList)
{
return "";
}
public override void Translate(VarTable varTable, LabelStack labelStack, List<FourExp> fourExpList)
{
string label = labelStack.NewLabel();
fourExpList.Add(FourExpFac.GenLabel(label));
statement.Translate(varTable, labelStack, fourExpList);
string condition = expression.GetValue(varTable, labelStack, fourExpList);
fourExpList.Add(FourExpFac.GenJne(condition, 0 + "", label));
}
public override void Translate(VarTable varTable, LabelStack labelStack, List<FourExp> fourExpList)
{
string value = expression.GetValue(varTable, labelStack, fourExpList);
varTable.SetValue(this.identify, value);
}
public virtual void Translate(VarTable varTable, LabelStack labelStack, List<FourExp> fourExpList)
{
}