-
Notifications
You must be signed in to change notification settings - Fork 1
/
Copy pathparse.cpp
1137 lines (1099 loc) · 32.3 KB
/
parse.cpp
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
#include <stdio.h>
#include <tchar.h>
#include <iostream>
#include <string>
#include <string.h>
#include <stdlib.h>
#include "define.h"
using namespace std;
int funcTab[200]={0};//分程序（函数）索引数组
int funcIndex =0;//分程序索引指针i，填表时指向的是当前函数的分程序索引数组中的位置（即当前函数在符号表中的起始位置）
int tabIndex;//符号表指针，每增加1符号表表项多1,实际栈顶为tabIndex-1
int paraNums=0,type=-1,value=-1,size,level;
int tempSym;
int hasReturn=0,hasMain=0;
int labelNum=0;
int funcTmpNum=0;
int codeNum=0;
int printChar;
FILE* fp;
char proName[30];
char midValue[30];
table Table[200];
quaternary code[1000];
char id[30] ;
extern int symbol;
extern int number;
extern int err;
extern int lineNum;
extern string errorde[30];
extern char token[82];
extern char ch;
extern FILE* fin;
extern void getsym();
extern void error(int e);
void statement();
void stateList();
void valParameter();
void expression();
char* createLabel(){
char *newLabel = (char *)malloc(10*sizeof(char));
char counter[10];
memset(newLabel,0,10*sizeof(char));
newLabel[0] = 'l';
newLabel[1] = 'a';
newLabel[2] = 'b';
strcat(newLabel,itoa(labelNum++,counter,10));
return newLabel;
}
char* tempVal(){
char *newVal = (char *)malloc(10*sizeof(char));
char counter[10];
memset(newVal,0,10*sizeof(char));
newVal[0] = '$';
itoa(funcTmpNum++,counter,10);
strcat(newVal,counter);
return newVal;
}
void emit(char op[],char v1[],char v2[],char v3[]){
strcpy(code[codeNum].op,op);
strcpy(code[codeNum].var1,v1);
strcpy(code[codeNum].var2,v2);
strcpy(code[codeNum++].var3,v3);
}
bool judgeEOF(){
if (symbol==eof) return true;
else return false;
}
void skip(int op){
if(op==0 || op==1 || op==2){
while (symbol!=CONST && symbol!=INT && symbol!=CHAR && symbol!=VOID && symbol!=IF
&& symbol!=DO && symbol!=FOR && symbol!=RETURN && symbol!=SCANF && symbol!=PRINTF){
if(judgeEOF())return;
getsym();
}
}else if(op==3 || op==4){
while (symbol!=SEMICOLON) {
if(judgeEOF())return;
getsym();
}
}else if(op==5){
while (symbol!=INT && symbol!=CHAR&& symbol!=VOID) {
if(judgeEOF())return;
getsym();
}
}
}
bool checkNextSym(int need,int sym,int e,int sk){
if(need==1)getsym();
if(symbol!=sym){
error(e);
skip(sk);
return true;
}else
return false;
}
void midcodeToFile(){
int i= 0;
fp=fopen("midcode.txt","w+");
while (i<codeNum) {
fprintf(fp,"%s,\t",code[i].op);
fprintf(fp,"%s,\t",code[i].var1);
fprintf(fp,"%s,\t",code[i].var2);
fprintf(fp,"%s;\n",code[i].var3);
if (strcmp(code[i].op,"end")==0)
fprintf(fp,"\n");
i++;
}
fclose(fp);
return;
}
void insertTable(char nam[],int typ, int val,int siz,int par,int index,int lev){
int tmpIndex;
if(index>199){
error(1);
return ;
}
if(typ==functype){
tmpIndex=1;
while(tmpIndex<=funcIndex){
if(strcmp(Table[funcTab[tmpIndex]].name,nam)==0&&Table[tmpIndex].level==lev){
error(5);
return;
}
tmpIndex++;
}
tmpIndex=0;
while(tmpIndex<=funcTab[1]){
if(strcmp(Table[tmpIndex].name,nam)==0&&Table[tmpIndex].level==lev){
error(5);
return;
}
tmpIndex++;
}
}else {
tmpIndex=funcTab[funcIndex];
while(tmpIndex<index){ //优先在当前函数中查找是否有重复定义
if(strcmp(Table[tmpIndex].name,nam)==0&&Table[tmpIndex].level==lev){
error(5);
return;
}
tmpIndex++;
}
tmpIndex=0;
if(typ!=paratype)//参数无条件先放入符号表中，非参数才继续查找
while(tmpIndex<funcTab[1]){//在全局变量中查找是否有重复定义
if(strcmp(Table[tmpIndex].name,nam)==0&&Table[tmpIndex].level==lev){
error(5);
return;
}
tmpIndex++;
}
}
strcpy(Table[index].name,nam);
Table[index].type=typ;
Table[index].value=val;
Table[index].size=siz;
Table[index].paranum=par;
Table[index].level=lev;
if(typ==functype){
funcTab[++funcIndex]=index;
}
tabIndex++;
}
void clearFuncTab(){
int temp1 = tabIndex-1;
int temp2;
while((Table[temp1].type==inttype || Table[temp1].type==chartype ||Table[temp1].type==constinttype
|| Table[temp1].type==constchartype|| Table[temp1].type==paratype)){
Table[temp1].type = 0;
Table[temp1].size = 0;
Table[temp1].paranum = 0;
Table[temp1].value = 0;
temp2 = 0;
while (temp2<30)
Table[temp1].name[temp2++] = '\0';
temp1--;
}
tabIndex = temp1+1;////设置新的符号表栈顶指针
return;
}
int searchTab(char nam[],int isFunc,int isArr){
int tmpIndex;
if(isFunc==1){
tmpIndex=1;
while(tmpIndex<=funcIndex){
if(strcmp(Table[funcTab[tmpIndex]].name,nam)==0)
break;
tmpIndex++;
}
if(tmpIndex>funcIndex){
error(6);
printf("%s\n",nam);
return -1;
}
if (Table[funcTab[tmpIndex]].paranum!=paraNums) {
error(9);
return -3;
}
return funcTab[tmpIndex];//查找成功返回在符号表中位置
}else {
tmpIndex=funcTab[funcIndex];//优先在当前分程序符号表中查找
while (tmpIndex<tabIndex) {
if (strcmp(Table[tmpIndex].name,nam)==0 && Table[tmpIndex].type!=functype && (isArr==0 || Table[tmpIndex].size>0)) return tmpIndex;
tmpIndex++;
}
tmpIndex=0;
while(tmpIndex<funcTab[1]){
if (strcmp(Table[tmpIndex].name,nam)==0 && Table[tmpIndex].type!=functype && (isArr==0 || Table[tmpIndex].size>0)) return tmpIndex;
tmpIndex++;
}
if(tmpIndex==funcTab[1]){
error(8);
return -1;
}
}
return -1;
}
//＜常量定义＞ ::= int＜标识符＞＝＜整数＞{,＜标识符＞＝＜整数＞} | char＜标识符＞＝＜字符＞{,＜标识符＞＝＜字符＞}
//＜整数＞ ::= ［＋｜－］＜无符号整数＞｜０
void constDefine(int preSym){
if(checkNextSym(0,ident,11,3))return;
strcpy(id,token);
if(checkNextSym(1,EQUAL,10,3))return;
getsym();
if(symbol==PLUS||symbol==MINUS){
int sign= symbol;
if(checkNextSym(1,integer,12,3))return;
if(preSym==INT){
if(sign==PLUS) value = number;
else if(sign==MINUS) value = 0-number;
}
insertTable(id,type,value,0,0,tabIndex,level);
char tmpVal[30];
itoa(value,tmpVal,10);
emit((char*)"const",(char*)"int",tmpVal,id);
}else {
if(preSym==INT&&symbol==integer){
insertTable(id,type,number,0,0,tabIndex,level);
char tmpVal[30];
value = number;
itoa(value,tmpVal,10);
emit((char*)"const",(char*)"int",tmpVal,id);
}else if(preSym==CHAR&&symbol==character){
value=token[0];
insertTable(id,type,value,0,0,tabIndex,level);
emit((char*)"const",(char*)"char",token,id);
}else {
error(14);
skip(3);
return;
}
}
getsym();
return ;
}
//＜常量说明＞ ::= const＜常量定义＞;{ const＜常量定义＞;}
void constDeclare(){
int preSym;
if(checkNextSym(0,CONST,7,4))return;
getsym();
if (symbol==INT || symbol==CHAR) {
if (symbol==INT) type= constinttype;
else if (symbol==CHAR) type = constchartype;
paraNums = 0;
preSym=symbol;
getsym();
constDefine(preSym);
while (symbol==COMMA) {
getsym();
constDefine(preSym);
}
if(checkNextSym(0,SEMICOLON,15,0))return;
tempSym=symbol;
}else {
error(16);
skip(0);
return;
}
getsym();
return;
}
//定义头部 int a; char b,c; int a2[3]; int func(){}//注意需要预读，以及记录当时的文件指针位置以及返回！！！！
void defineHead(){
if(symbol==INT||symbol==CHAR){
if(symbol==INT) type=inttype;
else type=chartype;
if(checkNextSym(1,ident,0,3))return;
else strcpy(id,token);
}else {
error(16);
while (symbol!=COMMA && symbol!=L_SMALL && symbol!=R_SMALL) {
if(judgeEOF())return;
getsym();
}
return ;
}
getsym();
return ;
}
//＜变量定义＞ ::= ＜类型标识符＞(＜标识符＞|＜标识符＞‘[’＜无符号整数＞‘]’){,(＜标识符＞|＜标识符＞‘[’＜无符号整数＞‘]’ )}
void varDefine(){
defineHead();
if(symbol==COMMA){
insertTable(id,type,0,0,0,tabIndex,level);
if(type==inttype) emit((char*)"int",(char*)" ",(char*)" ",id);
else if(type==chartype) emit((char*)"char",(char*)" ",(char*)" ",id);
while (symbol==COMMA){
if(checkNextSym(1,ident,0,4))return;
strcpy(id,token);
getsym();
if(symbol!=L_MIDDLE){
insertTable(id,type,0,0,0,tabIndex,level);
if(type==inttype) emit((char*)"int",(char*)" ",(char*)" ",id);
else if(type==chartype) emit((char*)"char",(char*)" ",(char*)" ",id);
}else if(symbol==L_MIDDLE){
if(checkNextSym(1,integer,12,4))return;
size=number;
if(checkNextSym(1,R_MIDDLE,18,4))return;
insertTable(id,type,0,size,0,tabIndex,level);
char q[30];
itoa(size,q,10);
if(type==inttype) emit((char*)"int",(char*)"[]",q,id);
else if(type==chartype) emit((char*)"char",(char*)"[]",(char*)q,id);
size=0;
getsym();
continue;
}
}
}else if(symbol==L_MIDDLE){ //int a[10]
if(checkNextSym(1,integer,12,4))return;
size=number;
if(checkNextSym(1,R_MIDDLE,18,4))return;
insertTable(id,type,0,size,0,tabIndex,level);
char q[30];
itoa(size,q,10);
if(type==inttype) emit((char*)"int",(char*)"[]",q,id);
else if(type==chartype) emit((char*)"char",(char*)"[]",q,id);
getsym();
if(symbol==COMMA){//int a[10],b.......
while (symbol==COMMA) {
if(checkNextSym(1,ident,0,4))return;
strcpy(id,token);
getsym();
if(symbol!=L_MIDDLE){
insertTable(id,type,0,0,0,tabIndex,level);
if(type==inttype) emit((char*)"int",(char*)" ",(char*)" ",id);
else if(type==chartype) emit((char*)"char",(char*)" ",(char*)" ",id);
}else if(symbol==L_MIDDLE){//int a[10],b[10],......
if(checkNextSym(1,integer,12,4))return;
size=number;
if(checkNextSym(1,R_MIDDLE,18,4))return;
insertTable(id,type,0,size,0,tabIndex,level);
char q[30];
itoa(size,q,10);
if(type==inttype) emit((char*)"int",(char*)"[]",q,id);
else if(type==chartype) emit((char*)"char",(char*)"[]",(char*)"q",id);
getsym();
continue;
}
}
}//int a[10],b...的特例讨论结束
}//int a[10] 情况讨论结束;
else {//既不是逗号也不是中括号，其实就是;或者 (，但是小括号不在这里分析 那么就把这个标识符填表即可
insertTable(id,type,0,0,0,tabIndex,level);
if(type==inttype) emit((char*)"int",(char*)" ",(char*)" ",id);
else if(type==chartype) emit((char*)"char",(char*)" ",(char*)" ",id);
}
return ;
}
//＜变量说明部分＞ ::= ＜变量定义＞;{＜变量定义＞;}
void varDeclare(){
varDefine();
if(checkNextSym(0,SEMICOLON,15,0))return;
getsym();
return;
}
//＜参数表＞ ::= ＜类型标识符＞＜标识符＞{,＜类型标识符＞＜标识符＞}| ＜空＞
void parameters(){
int i=0; //记录参数个数
if( symbol==INT||symbol==CHAR ) {
int tmpSym1;
tmpSym1=symbol;
do{
tmpSym1=symbol;
if (symbol==COMMA)
getsym();
if(tmpSym1==COMMA&&(symbol==INT||symbol==CHAR))
tmpSym1=symbol;
defineHead();
type = paratype;
insertTable(id,type,0,0,0,tabIndex,level); //将行数参数插入符号表,参数也要入表
if(tmpSym1==INT)
emit((char*)"para",(char*)"int",(char*)"0",id);
else if(tmpSym1==CHAR)
emit((char*)"para",(char*)"char",(char*)"0",id);
i++;
}while(symbol==COMMA);
}
paraNums = i;
Table[funcTab[funcIndex]].paranum = paraNums;//插入函数的参数个数
return;
}
//＜因子＞ ::= ＜标识符＞｜＜标识符＞‘[’＜表达式＞‘]’｜＜整数＞|＜字符＞｜＜有返回值函数调用语句＞|‘(’＜表达式＞‘)’
void factor(){
char names[30],tmp[30];
int res;
if (symbol==ident) {
strcpy(id,token);
strcpy(names,id);
getsym();
if (symbol==L_SMALL) {
getsym();
valParameter();
if(checkNextSym(0,R_SMALL,20,1))return;
res = searchTab(names,1,0);
if (res==-1 || Table[res].type!=functype ||(Table[res].type==functype&&Table[res].value==0) ) {//找不到定义的标识符或者不是函数或者不是有返回值的函数
error(8);
skip(1);
return;
}
if(Table[res].size==0)
printChar++;
strcpy(tmp,tempVal());//生成临时变量
if(Table[res].size==0)
emit((char*)"call",names,(char*)"int",tmp);//将调用的返回值存放在临时变量里面
if(Table[res].size==1)
emit((char*)"call",names,(char*)"char",tmp);//将调用的返回值存放在临时变量里面
strcpy(midValue,tmp);
getsym();
return;
}
else if(symbol==L_MIDDLE){//＜标识符＞‘[’＜表达式＞‘]’
res = searchTab(names,0,1);
if(res<0||Table[res].size==0){////找不到变量或者变量不是个数组变量
error(8); //"="左边是不合法的标识符
skip(1);
return ;
}
int vl=Table[res].size;
getsym();
expression();
char tmpArrVal[30];
strcpy(tmpArrVal,midValue);
if(tmpArrVal[0]>='0'&&tmpArrVal[0]<='9'){/////如果tmpArrVal是个数字，要检查数组越界
int a;
a=atoi(tmpArrVal);
if(a>=vl){
error(13);
skip(1);
return ;
}
}
if(checkNextSym(0,R_MIDDLE,18,1))return;
strcpy(tmp,tempVal());
emit((char*)"=[]",names,tmpArrVal,tmp);
strcpy(midValue,tmp);/////因子的返回值存入midValue, 返回的数组名字+[tmpArrVal]
getsym();
return ;
}else {
res = searchTab(names,0,0);
if (res==-1) {
error(8);
skip(1);
return;
}
}
strcpy(midValue,names);
return;
}
if (symbol==L_SMALL) {
getsym();
expression();
if (symbol!=R_SMALL) {
error(20);
skip(0);
return;
}
getsym();
return;
}
// ＜整数＞|＜字符＞
//＜整数＞ ::= ［＋｜－］＜无符号整数＞｜０
if (symbol==PLUS || symbol==MINUS|| symbol==integer||symbol==character) {
if (symbol==PLUS) getsym();
else if (symbol==MINUS) {
int k=0;
getsym();
while (token[k++]!='\0');
token[k+1] = '\0';
while (k!=0) {
token[k] = token[k-1];
k--;
}
token[0] = '-';
}
strcpy(midValue,token);//整数赋值给midValue
if(symbol==character){
char charVal[30];
itoa(int(token[0]),charVal,10);
strcpy(midValue,charVal);
printChar--;
}
getsym();
return;
}
error(0); //表达式缺失或错误
skip(0);
return;
}
//＜项＞ ::= ＜因子＞{＜乘法运算符＞＜因子＞}
void term(){
char fact1[30],fact2[30],fact3[30];
factor();
strcpy(fact3,midValue);//这种操作是为了对付只有赋值的情况,，如果无乘除，那么p1、p2没什么用
while (symbol==MUL|| symbol==DIV) {
printChar++;
int tmpSym=symbol;
strcpy(fact1,fact3);////有乘除时第一个操作数放在p1
getsym();
factor();
strcpy(fact2,midValue);/////第二个操作数放在p2
strcpy(fact3,tempVal());//申请临时变量
if (tmpSym==MUL)
emit((char*)"imul",fact1,fact2,fact3);
if (tmpSym==DIV)
emit((char*)"idiv",fact1,fact2,fact3);
continue;
}
strcpy(midValue,fact3); //每一个项，计算后的值都在midValue里面
return;
}
//＜表达式＞ ::= ［＋｜－］＜项＞{＜加法运算符＞＜项＞}
void expression(){
char term1[30],term2[30],term3[30];
if (symbol==PLUS || symbol==MINUS) {
printChar++;
if (symbol==PLUS) {
getsym();
term();
strcpy(term3,midValue);
}
if (symbol==MINUS) {
getsym();
term();
strcpy(term1,midValue);
strcpy(term3,tempVal());//place3 为临时变量,tempVal 生成临时变量以$开头
emit((char*)"sub",(char*)"0",term1,term3);
}
}
else {
term();
strcpy(term3,midValue);
}
while (symbol==PLUS || symbol==MINUS) {
printChar++;
strcpy(term1,term3);//////把上一个项与项计算得到的结果记为新的源操作数1
if (symbol==PLUS) {
getsym();
term();
strcpy(term2,midValue);////当前项的计算结果
strcpy(term3,tempVal());//新成新的临时变量
emit((char*)"add",term1,term2,term3);//将项与项的加法运算结果存到新的临时变量里
continue ;
}
if (symbol==MINUS) {
getsym();
term();
strcpy(term2,midValue);
strcpy(term3,tempVal());
emit((char*)"sub",term1,term2,term3);
continue ;
}
}
strcpy(midValue,term3);//把表达式的最终值存放在midValue之中
return;
}
//＜条件＞ ::= ＜表达式＞＜关系运算符＞＜表达式＞｜＜表达式＞ //表达式为0条件为假，否则为真
void ifLabel(char* label){
char express1[30],express2[30];
expression();
strcpy(express1,midValue); //条件至少有一个表达式
int tmpSym1=symbol;
if (tmpSym1==LESS || tmpSym1==G_EQUAL || tmpSym1==GREATER || tmpSym1==L_EQUAL || tmpSym1==NOT_EQUAL || tmpSym1==D_EQUAL) {
getsym();
expression();
strcpy(express2,midValue);
if (tmpSym1==LESS)
emit((char*)"jge",express1,express2,label);
else if (tmpSym1==L_EQUAL)
emit((char*)"jnle",express1,express2,label);
else if (tmpSym1==GREATER)
emit((char*)"jle",express1,express2,label);
else if (tmpSym1==G_EQUAL)
emit((char*)"jnge",express1,express2,label);
else if (tmpSym1==NOT_EQUAL)
emit((char*)"jz",express1,express2,label);
else if (tmpSym1==D_EQUAL)
emit((char*)"jnz",express1,express2,label);
return;
}
strcpy(express2,"0");
emit((char*)"jz",express1,express2,label);/////看表达式的值是不是等于0，为0跳转
return;
}
//＜条件语句＞ ::= if ‘(’＜条件＞‘)’＜语句＞［else＜语句＞］
void ifStatement(){
char label1[30],label2[30];
char ifLabelvalue[30];
strcpy(label1,createLabel());
strcpy(label2,createLabel());
if(checkNextSym(1,L_SMALL,19,2))return;
getsym();
ifLabel(label1);
strcpy(ifLabelvalue,midValue);
if(checkNextSym(0,R_SMALL,20,2))return;
getsym();
statement();
emit((char*)"jmp",(char*)" ",(char*)" ",label2);
emit((char*)"label",(char*)" ",(char*)" ",label1);
if(symbol==ELSE){
getsym();
statement();
}
emit((char*)"label",(char*)" ",(char*)" ",label2);
return ;
}
//＜循环语句＞
void doStatement(){
char label1[10],label2[10];
strcpy(label1,createLabel());
strcpy(label2,createLabel());
getsym();
emit((char*)"label",(char*)" ",(char*)" ",label1);//设置跳转回来的标签
statement();
if(checkNextSym(0,WHILE,26,2))return;
if(checkNextSym(1,L_SMALL,19,2))return;
getsym();
ifLabel(label2);//条件为假时跳到label2
if(checkNextSym(0,R_SMALL,18,2))return;
emit((char*)"jmp",(char*)" ",(char*)" ",label1);
emit((char*)"label",(char*)" ",(char*)" ",label2);
getsym();
return;
}
void forStatement(){
char label1[10],label2[10],names1[30],names2[30],tmp_num[30],tmp_mid[30];
int res,sign;
strcpy(label1,createLabel());
strcpy(label2,createLabel());
if(checkNextSym(1,L_SMALL,19,2))return;
if(checkNextSym(1,ident,0,2))return;
res = searchTab(token,0,0);
if (res<0||Table[res].value!=0||Table[res].size!=0) {//找不到变量或者找到的是个常量或者是个数组变量
error(12); //"="左边是不合法的标识符
skip(1);
return ;
}
strcpy(names1,token);
if(checkNextSym(1,EQUAL,10,2))return;
getsym();
expression();
emit((char*)"mov", midValue,(char*)" ",names1);
if(checkNextSym(0,SEMICOLON,15,2))return;
getsym();
emit((char*)"label",(char*)" ",(char*)" ",label1);
ifLabel(label2);
if(checkNextSym(0,SEMICOLON,15,2))return;
if(checkNextSym(1,ident,0,2))return;
if(checkNextSym(1,EQUAL,10,2))return;
if(checkNextSym(1,ident,0,2))return;
strcpy(names2,token);
getsym();
if(symbol!=PLUS && symbol!=MINUS){
error(17);
skip(2);
return;
}
sign=symbol;
if(checkNextSym(1,integer,12,2))return;
strcpy(tmp_num,token);
if(checkNextSym(1,R_SMALL,20,2))return;
getsym();
statement();
strcpy(tmp_mid,tempVal());
if(sign==PLUS)emit((char*)"add",names2,tmp_num,tmp_mid);
else emit((char*)"sub",names2,tmp_num,tmp_mid);
emit((char*)"mov", tmp_mid,(char*)" ",names1);
emit((char*)"jmp",(char*)" ",(char*)" ",label1);
emit((char*)"label",(char*)" ",(char*)" ",label2);
}
//＜读语句＞ ::= scanf ‘(’＜标识符＞{,＜标识符＞}‘)’
void readStatement(){
char names[30];
int res;
if(checkNextSym(1,L_SMALL,19,2))return;
do{
if(checkNextSym(1,ident,0,2))return;
strcpy(id,token);
strcpy(names,id);
res = searchTab(names,0,0);
if (res==-1 || Table[res].type==functype||Table[res].size!=0) {
error(8); //不合法的标识符
skip(2);
return;
}
if(Table[res].type==inttype)
emit((char*)"scanf",(char*)"int",(char*)" ",names);
else if(Table[res].type==chartype)
emit((char*)"scanf",(char*)"char",(char*)" ",names);
getsym();
}while(symbol==COMMA);
if(checkNextSym(0,R_SMALL,20,2))return;
getsym();
return;
}
//＜写语句＞ ::= printf ‘(’ ＜字符串＞,＜表达式＞ ‘)’| printf ‘(’＜字符串＞ ‘)’| printf ‘(’＜表达式＞‘)’
void writeStatement(){
char str1[200]="\0",express1[30]=" ";
if(checkNextSym(1,L_SMALL,19,2))return;
getsym();
if (symbol==text) {
strcpy(str1,token);
getsym();
if (symbol==COMMA) {
getsym();
printChar=0;
expression();
strcpy(express1,midValue);
}
}else {
printChar=0;
expression();
strcpy(express1,midValue);
}
if(checkNextSym(0,R_SMALL,20,2))return;
if(printChar==-1 && strcmp(express1," ")!=0){
emit((char*)"printf",str1,express1,(char*)"1");
}
else
emit((char*)"printf",str1,express1,(char*)" ");
printChar=0;
getsym();
return;
}
//＜返回语句＞ ::= return[‘(’＜表达式＞‘)’]
void returnStatement(){
char express[30];
getsym();
if(symbol==L_SMALL){
getsym();
expression();
strcpy(express,midValue);
if(checkNextSym(0,R_SMALL,20,2))return;
emit((char*)"ret",(char*)" ",(char*)" ",express);
hasReturn++;
getsym();
}else emit((char*)"ret",(char*)" ",(char*)" ",(char*)" ");
return ;
}
//＜值参数表＞ ::= ＜表达式＞{,＜表达式＞}｜＜空＞
void valParameter(){
char paras[100][100];
int j = 0;
do {
if (symbol==COMMA) getsym();
if (symbol==PLUS || symbol==MINUS || symbol==ident ||symbol==L_SMALL || symbol==character||symbol==integer) {
expression();
strcpy(paras[j],midValue);
j++;
}
}while (symbol==COMMA);
paraNums = j;
for(j=0;j<paraNums;j++)
emit((char*)"para",(char*)" ",(char*)"1",paras[j]);
return ;
}
void statement(){
int res;
if(symbol==SEMICOLON){
return;
}
if(symbol==IF){
ifStatement();
return;
}
if (symbol==DO) {
doStatement();
return;
}
if (symbol==FOR) {
forStatement();
return;
}
if (symbol==L_BIG) {
getsym();
stateList();
if(checkNextSym(0,R_BIG,22,1))return;
getsym();
return;
}
if (symbol==SCANF) {
readStatement();
if(checkNextSym(0,SEMICOLON,15,1))return;
getsym();
return;
}
if (symbol==PRINTF) {
writeStatement();
if(checkNextSym(0,SEMICOLON,15,1))return;
getsym();
return;
}
if (symbol==RETURN) {
returnStatement();
if(checkNextSym(0,SEMICOLON,15,1))return;
getsym();
return;
}
if (symbol==ident) {
char names[30];
strcpy(id,token);
strcpy(names,id);
getsym();
//＜赋值语句＞ ::= ＜标识符＞＝＜表达式＞|＜标识符＞‘[’＜表达式＞‘]’=＜表达式＞
if (symbol==EQUAL) {
res = searchTab(names,0,0);
if (res<0||Table[res].type==constchartype||Table[res].type==constinttype||Table[res].size!=0) {//找不到变量或者找到的是个常量或者是个数组变量
error(8);
skip(1);
return ;
}
getsym();
expression();
emit((char*)"mov", midValue,(char*)" ",names);
if(checkNextSym(0,SEMICOLON,15,1))return;
getsym();
return;
}
if(symbol==L_MIDDLE){
res = searchTab(names,0,1);
if(res<0||Table[res].size==0){//找不到变量或者变量不是个数组变量
error(8);
skip(1);
return ;
}
int arrLength=Table[res].size;
getsym();
expression();
char tmpArrVal[30];
strcpy(tmpArrVal,midValue);
if(tmpArrVal[0]>='0'&&tmpArrVal[0]<='9'){//如果tmpArrVal是个数字，要检查数组越界
int a;
a=atoi(tmpArrVal);
if(a>=arrLength){
error(13);
skip(1);
return ;
}
}
if(checkNextSym(0,R_MIDDLE,18,1))return;
if(checkNextSym(1,EQUAL,10,1))return;
getsym();
expression();
char tempplace[30];
strcpy(tempplace,tempVal());
emit((char*)"[]=",tmpArrVal,midValue,names);
if(checkNextSym(0,SEMICOLON,15,1))return;
getsym();
return;
}
//函数调用语句
if (symbol==L_SMALL) {
getsym();
valParameter();
if(checkNextSym(0,R_SMALL,20,1))return;
res = searchTab(names,1,0);
if (res==-1 || res==-3||Table[res].type!=functype) {
error(8);
skip(1);
return;
}
if(Table[res].size==0)
emit((char*)"call",names,(char*)"int",(char*)" ");
else if(Table[res].size==1)
emit((char*)"call",names,(char*)"char",(char*)" ");
else
emit((char*)"call",names,(char*)" ",(char*)" ");
if(checkNextSym(1,SEMICOLON,15,1))return;
getsym();
}
else {
error(0); //不合法的句子
skip(1);
return;
}
return;
}
if(symbol==SEMICOLON){
getsym();
return ;
}
else if(symbol==R_BIG){
return;
}
error(0);
skip(1);
return;
}
void stateList(){
statement();
while(symbol==IF||symbol==ELSE||symbol==DO||symbol==FOR||symbol==SCANF||symbol==PRINTF
||symbol==L_BIG||symbol==ident||symbol==RETURN||symbol==SEMICOLON){
if(symbol!=SEMICOLON)statement();
else getsym();
}
}
//＜复合语句＞ ::= ［＜常量说明＞］［＜变量说明＞］＜语句列＞
void comStatement(){
tempSym=0;
if(symbol==CONST){
constDeclare();
}
while(tempSym==SEMICOLON){
if(symbol==CONST)
constDeclare();
else break;
}
while(symbol==INT||symbol==CHAR){
int a=ftell(fin);//记录下当前读到的文件位置，以便预读过后返回分析
int tmpSym2=symbol;
if(symbol==INT) type=inttype;
if(symbol==CHAR) type = chartype;
getsym();
if(symbol==ident){
strcpy(id,token);
getsym();
if(symbol==COMMA||symbol==L_MIDDLE){
symbol=tmpSym2;
fseek(fin,a,SEEK_SET);//继续分析
varDeclare();
continue;
}
else if(symbol==SEMICOLON){
insertTable(id,type,0,0,0,tabIndex,level);
if(type==inttype) emit((char*)"int",(char*)" ",(char*)" ",id);
else if(type==chartype) emit((char*)"char",(char*)" ",(char*)" ",id);
getsym();
continue;
}
else {
error(0);
skip(1);
return;
}
}
}
stateList();
return;
}
//＜程序＞ ::= ［＜常量说明＞］［＜变量说明＞］{＜有返回值函数定义＞|＜无返回值函数定义＞}＜主函数＞
void procedure(){
level=0;
getsym();
if(symbol==CONST)