generate.java

基于c0文法写的生成p-code的编译器

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.util.LinkedList;

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
import java.util.Vector;

/**
 *
 * @author lilac
 */
public class Generate {

    private Vector<Constpair> topconst = null;
    public Vector<String> topvar = null;
    private LinkedList<Function> funclist = null;
    public Vector<String> assembler = null;      //汇编输出
    private Function ff = null;                   //当前函数
    private int pcount = 0;                       //参数计数
    private String condition = null;
    public Vector<String> st = null;          //printf用字符串表
    private int stc = 0;                         //字符串计数
    private String path;
    public String warn=null;

    public Generate(Vector<Constpair> topconst, Vector<String> topvar, LinkedList<Function> funclist, String path) {
        this.funclist =funclist;
        this.topconst = topconst;
        this.topvar = topvar;
        this.assembler = new Vector<String>();
        this.st = new Vector<String>();
        this.path = path;
        st.add("@_IO_DATA dword ?");
        st.add("@_IO_STR byte \"%d\", 0");
        st.add("@_NEWLINE byte 0dh,0ah,0");

    }
    //给出该参数或变量的地址表示，若为全局变量则返回原字符串
    private String findadr(String ss) {
        Integer i;
        i = ff.pmap.get(ss);              //在参数表里找
        if (i != null) {
            return "[ebp + " + i + " ]";
        }
        i = ff.vmap.get(ss);
        if (i != null) {                     //再在变量表里找
            return "[ebp - " + i + " ]";
        }
        if (ss.equals("@teax")) {          //若去函数调用的返回值怎译为eax
            return "eax";
        }
        
        if(ss.charAt(0)>='0' && ss.charAt(0)<='9'){    //当为全局常量时返回原数字
            return ss;                       
        }else{
            return "$"+ss;                    //当为全局变量时直接返回加$的字符串
        }
                                              
    }

    public void Generate() {
        FileWriter fw = null;


        for (Function func : this.funclist) {     //遍历所有函数
            ff = func;                            //ff存当前函数，以为后面方法调用从中获得数据
            int space = (ff.vmap.size() + 4) * 4;   //算出函数调用需要的保留区大小，存为space
            assembler.add("@f" + func.name + ":");  //写入汇编函数头
            assembler.add("push ebp");
            assembler.add("mov ebp,esp");
            assembler.add("sub esp," + space);

            for (Four four : func.fourlist) {      //遍历该函数的所有四元式
                switch (four.op) {                 //根据四元式的操作符op，转入相应的方法去添加对应的汇编代码
                    case Compile.ADD:
                        add(four);
                        break;
                    case Compile.SUB:
                        sub(four);
                        break;
                    case Compile.MUL:
                        mul(four);
                        break;
                    case Compile.DIV:
                        div(four);
                        break;
                    case Compile.MOV:
                        mov(four);
                        break;
                    case Compile.CALL:
                        call(four);
                        break;
                    case Compile.CMP:
                        cmp(four);
                        break;
                    case Compile.CONDITION:
                        condition(four);
                        break;
                    case Compile.J:
                        j(four);
                        break;
                    case Compile.JFALSE:
                        jfalse(four);
                        break;
                    case Compile.PRINTF:
                        print(four);
                        break;
                    case Compile.PUSHPARA:
                        pushpara(four);
                        break;
                    case Compile.RETURN:
                        ret(four);
                        break;
                    case Compile.SCANF:
                        scan(four);
                        break;
                    case Compile.STAMP:
                        stamp(four);
                        break;
                    }
            }
            if (func.fourlist.getLast().op != Compile.RETURN) {    //检查是否有返回语句，若没有自动添加，并向用户发出警告
                warn="Warning:Return Missing!";
                assembler.add("mov esp,ebp");
                assembler.add("pop ebp");
                assembler.add("ret");
            }
        }

        File ofile = new File(path);        //汇编输出文件
        try {
            ofile.createNewFile();
        } catch (IOException exc) {
        }
        try {
            fw = new FileWriter(ofile);
            fw.write(".386\n");
            fw.write(".MODEL FLAT\n");
            fw.write("includelib msvcrt.lib\n");
            fw.write("puts proto C\n");
            fw.write("printf proto C\n");
            fw.write("scanf proto C\n");
            fw.write(".STACK 4096\n");
            fw.write(".DATA\n");
            for(String s : this.topvar){
                fw.write("$"+s + " DWORD 0\n");
            }
            for (String s : st) {
                fw.write(s + '\n');
            }
            
            fw.write(".CODE\n");
            for (String s : assembler) {
                fw.write(s + '\n');
            }
            fw.write("_main:\n");
            fw.write("jmp near ptr @fmain\n");
            fw.write("end _main\n");
            fw.flush();
        } catch (FileNotFoundException ex) {
        } catch (IOException ex) {
        }

    }
//加法操作
    private void add(Four four) {
        assembler.add("mov eax, " + findadr(four.first));
        assembler.add("add eax, " + findadr(four.last));
        assembler.add("mov " + findadr(four.result) + ", eax");
    }
//函数调用操作
    private void call(Four four) {
        assembler.add("call " + "@f" + four.first);
        assembler.add("add esp, " + (pcount * 4));
        pcount = 0;
    }
//比较操作
    private void cmp(Four four) {
        assembler.add("mov eax, " + findadr(four.first));
        assembler.add("cmp eax, " + findadr(four.last));
    }
//把应满足的条件存入condition字段，使后面的跳转语句可以确定其条件
    private void condition(Four four) {
        condition = four.first;
    }
//除法操作
    private void div(Four four) {
        assembler.add("mov eax, " + findadr(four.first));
        assembler.add("cdq");
        assembler.add("mov ecx, " + findadr(four.last));
        assembler.add("idiv ecx");
        assembler.add("mov " + findadr(four.result) + ", eax");
    }
//无条件跳转操作
    private void j(Four four) {
        assembler.add("jmp near ptr @l" + four.first);
    }
//当不满足condition时跳转的操作
    private void jfalse(Four four) {
        switch (new Integer(condition).intValue()) {
            case Lex.EE:
                assembler.add("jne near ptr @l" + four.first);
                break;
            case Lex.NE:
                assembler.add("je near ptr @l" + four.first);
                break;
            case Lex.G:
                assembler.add("jle near ptr @l" + four.first);
                break;
            case Lex.L:
                assembler.add("jge near ptr @l" + four.first);
                break;
            case Lex.GE:
                assembler.add("jl near ptr @l" + four.first);
                break;
            case Lex.LE:
                assembler.add("jg near ptr @l" + four.first);
                break;
        }
        condition = null;
    }
//赋值操作
    private void mov(Four four) {
        assembler.add("mov eax, " + findadr(four.first));
        assembler.add("mov " + findadr(four.result) + ", eax");
    }
//乘法操作
    private void mul(Four four) {
        assembler.add("mov eax, " + findadr(four.first));
        assembler.add("mov ecx, " + findadr(four.last));
        assembler.add("imul ecx");
        assembler.add("mov " + findadr(four.result) + ", eax");
    }
//打印操作
    private void print(Four four) {
        String strname = "@str" + stc;
        switch (new Integer(four.result)) {
            case 0:
                // string
                st.add(strname + " byte " + four.first + ",0");
                stc++;
                assembler.add("lea eax, " + strname);
                assembler.add("push eax");
                assembler.add("call puts");
                assembler.add("add esp, 4");
                break;
            case 1:
                // integer
                assembler.add("mov eax," + findadr(four.last));
                assembler.add("push eax");
                assembler.add("lea eax, @_IO_STR");
                assembler.add("push eax");
                assembler.add("call printf");
                assembler.add("add esp, 8");
                break;
            case 2:
                // both
                /*
                st.add(strname + " BYTE " + four.first + ",0");
                stc++;
                assembler.add("mov eax," + findadr(four.last));
                assembler.add("push eax");
                assembler.add("lea eax, " + strname);
                assembler.add("push eax");
                assembler.add("call printf");
                assembler.add("add esp, 8");
                 */
                st.add(strname + " BYTE " + four.first + ",0");
                stc++;
                assembler.add("lea eax, " + strname);
                assembler.add("push eax");
                assembler.add("call puts");
                assembler.add("add esp, 4");

                assembler.add("mov eax, " + findadr(four.last));
                assembler.add("push eax");
                assembler.add("lea eax, @_IO_STR");
                assembler.add("push eax");
                assembler.add("call printf");
                assembler.add("add esp, 8");
                break;
        }
        assembler.add("lea eax,@_NEWLINE");
        assembler.add("push eax");
        assembler.add("call printf");
        assembler.add("add esp, 4");
    }
//推参数操作
    private void pushpara(Four four) {
        assembler.add("push " + findadr(four.first));
        pcount++;
    }
//返回操作
    private void ret(Four four) {
        if (four.first != null) {
            assembler.add("mov eax, " + findadr(four.first));
        }
        assembler.add("mov esp,ebp");
        assembler.add("pop ebp");
        assembler.add("ret");
    }
//读取操作
    private void scan(Four four) {
        assembler.add("lea eax, @_IO_DATA");
        assembler.add("push eax");
        assembler.add("lea eax, @_IO_STR");
        assembler.add("push eax");
        assembler.add("call scanf");
        assembler.add("add esp, 8");

        assembler.add("mov eax, @_IO_DATA");
        assembler.add("mov " + findadr(four.first) + ", eax");
    }
//标签
    private void stamp(Four four) {
        assembler.add("@l" + four.first + " :");
    }
//减法操作
    private void sub(Four four) {
        assembler.add("mov eax, " + findadr(four.first));
        assembler.add("sub eax, " + findadr(four.last));
        assembler.add("mov " + findadr(four.result) + ", eax");
    }
}