/**
* 处理生成函数的中间代码时
* 在函数的第一行地址前加入j指令跳转到函数的最后一行地址之后
*
*/
public override object VisitFunctionDeclaration([NotNull] CMMParser.FunctionDeclarationContext context)
{
string funcName = context.GetChild(1).GetText();
// jump到函数ret的下一行代码 最后再回填
IntermediateCode jumpCode = new IntermediateCode(InstructionType.j, context.Start.Line);
codes.Add(jumpCode);
// 保存局部变量表和大小
Dictionary <string, int> storedVariableTable = curLocalVariablesTable;
int storedVariableTableSize = curLocalVariablesTableLength;
curLocalVariablesTable = new Dictionary <string, int>();
curLocalVariablesTableLength = 0;
// 用于记录该函数的各种信息
FunctionInformation funcInfo = new FunctionInformation(funcName);
// 记录函数的起始地址
int funcAddress = codes.Count;
functionAddressTable.Add(funcName, funcAddress);
funcInfo.enrtyAddress = funcAddress;
// 访问参数列表
Visit(context.parameterClause());
// visit code block生成当前函数的中间代码
Visit(context.codeBlock());
// 填入函数的出口地址
funcInfo.outAddress = codes.Count - 1;
// 回填jump指令
jumpCode.setOperant(codes.Count);
funcInfo.localVariableTable = curLocalVariablesTable;
// 将函数信息保存到函数信息表中
functionInformations.Add(funcName, funcInfo);
// 恢复局部变量表和大小
curLocalVariablesTable = storedVariableTable;
curLocalVariablesTableLength = storedVariableTableSize;
return(null);
}
/// <summary>
/// Visit a parse tree produced by <see cref="CMMParser.functionDeclaration"/>.
/// <para>
/// The default implementation returns the result of calling <see cref="AbstractParseTreeVisitor{Result}.VisitChildren(IRuleNode)"/>
/// on <paramref name="context"/>.
/// </para>
/// </summary>
/// <param name="context">The parse tree.</param>
/// <return>The visitor result.</return>
public virtual Result VisitFunctionDeclaration([NotNull] CMMParser.FunctionDeclarationContext context)
{
return(VisitChildren(context));
}
/// <summary>
/// Exit a parse tree produced by <see cref="CMMParser.functionDeclaration"/>.
/// <para>The default implementation does nothing.</para>
/// </summary>
/// <param name="context">The parse tree.</param>
public virtual void ExitFunctionDeclaration([NotNull] CMMParser.FunctionDeclarationContext context)
{
}
