SQLite

Check-in [3b28b68e23]
Login

Many hyperlinks are disabled.
Use anonymous login to enable hyperlinks.

Overview
Comment:Improvements to the initialization of the push-down automoton for the Lemon-generated parser. Smaller and faster.
Downloads: Tarball | ZIP archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1: 3b28b68e232060f8b2fe2fe6fa478280da2006ff
User & Date: drh 2016-05-24 00:40:54.799
Context
2016-05-24
16:20
Fix an obscure problem with transactions written in "PRAGMA synchronous=full" mode on systems that do not support POWERSAFE_OVERWRITE causing an xSync() call to be omitted if the last frame written by a transaction is aligned to a sector boundary. This means that if a power failure or OS crash occurs very soon after such a transaction is committed, it may be lost following system recovery. (check-in: 37de3eab67 user: dan tags: trunk)
00:40
Improvements to the initialization of the push-down automoton for the Lemon-generated parser. Smaller and faster. (check-in: 3b28b68e23 user: drh tags: trunk)
2016-05-23
21:56
Use a pointer to the top of the stack rather than an index into the stack in the Lemon-generated parser template, for about 6.6% parser performance gain. (check-in: 3c2a770549 user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to tool/lempar.c.
︙︙
271
272
273
274
275
276
277

278
279
280

281
282
283

284
285
286
287
288
289
290


#if YYSTACKDEPTH<=0
/*
** Try to increase the size of the parser stack.
*/
static void yyGrowStack(yyParser *p){
  int newSize;

  yyStackEntry *pNew;

  newSize = p->yystksz*2 + 100;

  pNew = realloc(p->yystack, newSize*sizeof(pNew[0]));
  if( pNew ){
    p->yystack = pNew;

    p->yystksz = newSize;
#ifndef NDEBUG
    if( yyTraceFILE ){
      fprintf(yyTraceFILE,"%sStack grows to %d entries!\n",
              yyTracePrompt, p->yystksz);
    }
#endif








>



>



>








271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293


#if YYSTACKDEPTH<=0
/*
** Try to increase the size of the parser stack.
*/
static void yyGrowStack(yyParser *p){
  int newSize;
  int idx;
  yyStackEntry *pNew;

  newSize = p->yystksz*2 + 100;
  idx = p->yytos ? (int)(p->yytos - p->yystack) : 0;
  pNew = realloc(p->yystack, newSize*sizeof(pNew[0]));
  if( pNew ){
    p->yystack = pNew;
    p->yytos = &p->yystack[idx];
    p->yystksz = newSize;
#ifndef NDEBUG
    if( yyTraceFILE ){
      fprintf(yyTraceFILE,"%sStack grows to %d entries!\n",
              yyTracePrompt, p->yystksz);
    }
#endif
︙︙
313
314
315
316
317
318
319
320
321
322
323
324

325
326
327
328



329
330
331
332
333
334
335

** A pointer to a parser.  This pointer is used in subsequent calls
** to Parse and ParseFree.
*/
void *ParseAlloc(void *(*mallocProc)(YYMALLOCARGTYPE)){
  yyParser *pParser;
  pParser = (yyParser*)(*mallocProc)( (YYMALLOCARGTYPE)sizeof(yyParser) );
  if( pParser ){
    pParser->yytos = 0;
#ifdef YYTRACKMAXSTACKDEPTH
    pParser->yyhwm = 0;
#endif
#if YYSTACKDEPTH<=0

    pParser->yystack = NULL;
    pParser->yystksz = 0;
    yyGrowStack(pParser);
#endif



  }
  return pParser;
}

/* The following function deletes the "minor type" or semantic value
** associated with a symbol.  The symbol can be either a terminal
** or nonterminal. "yymajor" is the symbol code, and "yypminor" is








<




>




>
>
>








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

** A pointer to a parser.  This pointer is used in subsequent calls
** to Parse and ParseFree.
*/
void *ParseAlloc(void *(*mallocProc)(YYMALLOCARGTYPE)){
  yyParser *pParser;
  pParser = (yyParser*)(*mallocProc)( (YYMALLOCARGTYPE)sizeof(yyParser) );
  if( pParser ){

#ifdef YYTRACKMAXSTACKDEPTH
    pParser->yyhwm = 0;
#endif
#if YYSTACKDEPTH<=0
    pParser->yytos = NULL;
    pParser->yystack = NULL;
    pParser->yystksz = 0;
    yyGrowStack(pParser);
#endif
    pParser->yytos = pParser->yystack;
    pParser->yystack[0].stateno = 0;
    pParser->yystack[0].major = 0;
  }
  return pParser;
}

/* The following function deletes the "minor type" or semantic value
** associated with a symbol.  The symbol can be either a terminal
** or nonterminal. "yymajor" is the symbol code, and "yypminor" is
︙︙
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407

  void *p,                    /* The parser to be deleted */
  void (*freeProc)(void*)     /* Function used to reclaim memory */
){
  yyParser *pParser = (yyParser*)p;
#ifndef YYPARSEFREENEVERNULL
  if( pParser==0 ) return;
#endif
  while( pParser->yytos>=pParser->yystack ) yy_pop_parser_stack(pParser);
#if YYSTACKDEPTH<=0
  free(pParser->yystack);
#endif
  (*freeProc)((void*)pParser);
}

/*








|








399
400
401
402
403
404
405
406
407
408
409
410
411
412
413

  void *p,                    /* The parser to be deleted */
  void (*freeProc)(void*)     /* Function used to reclaim memory */
){
  yyParser *pParser = (yyParser*)p;
#ifndef YYPARSEFREENEVERNULL
  if( pParser==0 ) return;
#endif
  while( pParser->yytos>pParser->yystack ) yy_pop_parser_stack(pParser);
#if YYSTACKDEPTH<=0
  free(pParser->yystack);
#endif
  (*freeProc)((void*)pParser);
}

/*
︙︙
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532

   ParseARG_FETCH;
   yypParser->yytos--;
#ifndef NDEBUG
   if( yyTraceFILE ){
     fprintf(yyTraceFILE,"%sStack Overflow!\n",yyTracePrompt);
   }
#endif
   while( yypParser->yytos>=yypParser->yystack ) yy_pop_parser_stack(yypParser);
   /* Here code is inserted which will execute if the parser
   ** stack every overflows */
/******** Begin %stack_overflow code ******************************************/
%%
/******** End %stack_overflow code ********************************************/
   ParseARG_STORE; /* Suppress warning about unused %extra_argument var */
}








|








524
525
526
527
528
529
530
531
532
533
534
535
536
537
538

   ParseARG_FETCH;
   yypParser->yytos--;
#ifndef NDEBUG
   if( yyTraceFILE ){
     fprintf(yyTraceFILE,"%sStack Overflow!\n",yyTracePrompt);
   }
#endif
   while( yypParser->yytos>yypParser->yystack ) yy_pop_parser_stack(yypParser);
   /* Here code is inserted which will execute if the parser
   ** stack every overflows */
/******** Begin %stack_overflow code ******************************************/
%%
/******** End %stack_overflow code ********************************************/
   ParseARG_STORE; /* Suppress warning about unused %extra_argument var */
}
︙︙
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706

){
  ParseARG_FETCH;
#ifndef NDEBUG
  if( yyTraceFILE ){
    fprintf(yyTraceFILE,"%sFail!\n",yyTracePrompt);
  }
#endif
  while( yypParser->yytos>=yypParser->yystack ) yy_pop_parser_stack(yypParser);
  yypParser->yytos = 0;
  /* Here code is inserted which will be executed whenever the
  ** parser fails */
/************ Begin %parse_failure code ***************************************/
%%
/************ End %parse_failure code *****************************************/
  ParseARG_STORE; /* Suppress warning about unused %extra_argument variable */
}








|
<








697
698
699
700
701
702
703
704

705
706
707
708
709
710
711

){
  ParseARG_FETCH;
#ifndef NDEBUG
  if( yyTraceFILE ){
    fprintf(yyTraceFILE,"%sFail!\n",yyTracePrompt);
  }
#endif
  while( yypParser->yytos>yypParser->yystack ) yy_pop_parser_stack(yypParser);

  /* Here code is inserted which will be executed whenever the
  ** parser fails */
/************ Begin %parse_failure code ***************************************/
%%
/************ End %parse_failure code *****************************************/
  ParseARG_STORE; /* Suppress warning about unused %extra_argument variable */
}
︙︙
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745

){
  ParseARG_FETCH;
#ifndef NDEBUG
  if( yyTraceFILE ){
    fprintf(yyTraceFILE,"%sAccept!\n",yyTracePrompt);
  }
#endif
  while( yypParser->yytos>=yypParser->yystack ) yy_pop_parser_stack(yypParser);
  yypParser->yytos = 0;
  /* Here code is inserted which will be executed whenever the
  ** parser accepts */
/*********** Begin %parse_accept code *****************************************/
%%
/*********** End %parse_accept code *******************************************/
  ParseARG_STORE; /* Suppress warning about unused %extra_argument variable */
}








|
<








735
736
737
738
739
740
741
742

743
744
745
746
747
748
749

){
  ParseARG_FETCH;
#ifndef NDEBUG
  if( yyTraceFILE ){
    fprintf(yyTraceFILE,"%sAccept!\n",yyTracePrompt);
  }
#endif
  while( yypParser->yytos>yypParser->yystack ) yy_pop_parser_stack(yypParser);

  /* Here code is inserted which will be executed whenever the
  ** parser accepts */
/*********** Begin %parse_accept code *****************************************/
%%
/*********** End %parse_accept code *******************************************/
  ParseARG_STORE; /* Suppress warning about unused %extra_argument variable */
}
︙︙
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

#ifdef YYERRORSYMBOL
  int yyerrorhit = 0;   /* True if yymajor has invoked an error */
#endif
  yyParser *yypParser;  /* The parser */

  /* (re)initialize the parser, if necessary */
  yypParser = (yyParser*)yyp;
  if( yypParser->yytos==0 ){
#if YYSTACKDEPTH<=0
    if( yypParser->yystksz <=0 ){
      yyStackOverflow(yypParser);
      return;
    }
#endif
    yypParser->yytos = yypParser->yystack;
#ifndef YYNOERRORRECOVERY
    yypParser->yyerrcnt = -1;
#endif
    yypParser->yystack[0].stateno = 0;
    yypParser->yystack[0].major = 0;
#ifndef NDEBUG
    if( yyTraceFILE ){
      fprintf(yyTraceFILE,"%sInitialize. Empty stack. State 0\n",
              yyTracePrompt);
    }
#endif
  }
#if !defined(YYERRORSYMBOL) && !defined(YYNOERRORRECOVERY)
  yyendofinput = (yymajor==0);
#endif
  ParseARG_STORE;

#ifndef NDEBUG
  if( yyTraceFILE ){








|
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<








781
782
783
784
785
786
787
788



















789
790
791
792
793
794
795

#ifdef YYERRORSYMBOL
  int yyerrorhit = 0;   /* True if yymajor has invoked an error */
#endif
  yyParser *yypParser;  /* The parser */

  /* (re)initialize the parser, if necessary */
  yypParser = (yyParser*)yyp;
  assert( yypParser->yytos!=0 );



















#if !defined(YYERRORSYMBOL) && !defined(YYNOERRORRECOVERY)
  yyendofinput = (yymajor==0);
#endif
  ParseARG_STORE;

#ifndef NDEBUG
  if( yyTraceFILE ){
︙︙
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931

      yy_destructor(yypParser,(YYCODETYPE)yymajor,&yyminorunion);
      if( yyendofinput ){
        yy_parse_failed(yypParser);
      }
      yymajor = YYNOCODE;
#endif
    }
  }while( yymajor!=YYNOCODE && yypParser->yytos>=yypParser->yystack );
#ifndef NDEBUG
  if( yyTraceFILE ){
    yyStackEntry *i;
    char cDiv = '[';
    fprintf(yyTraceFILE,"%sReturn. Stack=",yyTracePrompt);
    for(i=&yypParser->yystack[1]; i<=yypParser->yytos; i++){
      fprintf(yyTraceFILE,"%c%s", cDiv, yyTokenName[i->major]);








|








902
903
904
905
906
907
908
909
910
911
912
913
914
915
916

      yy_destructor(yypParser,(YYCODETYPE)yymajor,&yyminorunion);
      if( yyendofinput ){
        yy_parse_failed(yypParser);
      }
      yymajor = YYNOCODE;
#endif
    }
  }while( yymajor!=YYNOCODE && yypParser->yytos>yypParser->yystack );
#ifndef NDEBUG
  if( yyTraceFILE ){
    yyStackEntry *i;
    char cDiv = '[';
    fprintf(yyTraceFILE,"%sReturn. Stack=",yyTracePrompt);
    for(i=&yypParser->yystack[1]; i<=yypParser->yytos; i++){
      fprintf(yyTraceFILE,"%c%s", cDiv, yyTokenName[i->major]);
︙︙