In the LEMON-generated parser, rearrange the meanings of integer action codes

so that reduce actions occur last.  This means that the most common case
(reduce actions) can be recognized with a single comparison operation, thus
speeding up the main parser loop, slightly.

FossilOrigin-Name: 7bfe7a360261ac7227840db49487c2f0fe338a2f1b868fcaada1e04a8d2b8f7a

diff --git a/manifest b/manifest
index 07c293333d7763ab094af33e0ce795669c614d74..d8e37c9644bcbe943950ddec5ebbf6687d5959df 100644 (file)
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Improved\sparser\stracing\soutput.
-D 2017-12-24T17:06:41.289
+C In\sthe\sLEMON-generated\sparser,\srearrange\sthe\smeanings\sof\sinteger\saction\scodes\nso\sthat\sreduce\sactions\soccur\slast.\s\sThis\smeans\sthat\sthe\smost\scommon\scase\n(reduce\sactions)\scan\sbe\srecognized\swith\sa\ssingle\scomparison\soperation,\sthus\nspeeding\sup\sthe\smain\sparser\sloop,\sslightly.
+D 2017-12-24T23:38:10.370
 F Makefile.in ceb40bfcb30ebba8e1202b34c56ff7e13e112f9809e2381d99be32c2726058f5
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc 6480671f7c129e61208d69492b3c71ce4310d49fceac83cfb17f1c081e242b69
@@ -1608,8 +1608,8 @@ F tool/genfkey.README cf68fddd4643bbe3ff8e31b8b6d8b0a1b85e20f4
 F tool/genfkey.test 4196a8928b78f51d54ef58e99e99401ab2f0a7e5
 F tool/getlock.c f4c39b651370156cae979501a7b156bdba50e7ce
 F tool/kvtest-speed.sh 4761a9c4b3530907562314d7757995787f7aef8f
-F tool/lemon.c e6056373044d55296d21f81467dba7632bbb81dc49af072b3f0e76338771497e
-F tool/lempar.c a427c2375df118fa52e69174ffbbf9e26878096f0a109df6b77062d6032afe18
+F tool/lemon.c 7c6919d98e459c0f8a3673be64b03425553733dba01c12939b2fadc30e4e2804
+F tool/lempar.c c8dd4dcf0bca9d7c27c62f7df12882c30db749cd9bb83d6f71796b9fabb94f6c
 F tool/libvers.c caafc3b689638a1d88d44bc5f526c2278760d9b9
 F tool/loadfts.c c3c64e4d5e90e8ba41159232c2189dba4be7b862
 F tool/logest.c 11346aa019e2e77a00902aa7d0cabd27bd2e8cca
@@ -1687,11 +1687,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 07c773148d8db185fa54991df09298b64f4fef28879e6c9395759265e8183977
-Q +c4951833c2b976223c2393d82fd2606068c71cd19612ca9df4e26debab980e32
-R 3f4f31cde41f94adafa8015552d0561b
-T *branch * lemon-improvements
-T *sym-lemon-improvements *
-T -sym-trunk *
+P 25be5750545b7b0ed9e1a1baca31611b354519688f875aa1590b21bb6ff42f1b
+R 02413a9b8686f5cb855fd9a72c28a347
 U drh
-Z 3f6d9f274761457d9d7dcc3ca6c0270c
+Z a4798d5b361261f3f5c39967bad11abf

diff --git a/manifest.uuid b/manifest.uuid
index bdf982cb8881fb8f18e639b44d0fd5571552ed04..d4db86c74456f01dfc43cca9cd45a902c522e2e6 100644 (file)
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-25be5750545b7b0ed9e1a1baca31611b354519688f875aa1590b21bb6ff42f1b
\ No newline at end of file
+7bfe7a360261ac7227840db49487c2f0fe338a2f1b868fcaada1e04a8d2b8f7a
\ No newline at end of file

diff --git a/tool/lemon.c b/tool/lemon.c
index acc5450c993d9481a387416f24bd6d43e1126a8e..33ef43d1b1ac8f63da0de895ee20f9ad5206f79c 100644 (file)
--- a/tool/lemon.c
+++ b/tool/lemon.c
@@ -384,6 +384,12 @@ struct lemon {
   int nrule;               /* Number of rules */
   int nsymbol;             /* Number of terminal and nonterminal symbols */
   int nterminal;           /* Number of terminal symbols */
+  int minShiftReduce;      /* Minimum shift-reduce action value */
+  int errAction;           /* Error action value */
+  int accAction;           /* Accept action value */
+  int noAction;            /* No-op action value */
+  int minReduce;           /* Minimum reduce action */
+  int maxAction;           /* Maximum action value of any kind */
   struct symbol **symbols; /* Sorted array of pointers to symbols */
   int errorcnt;            /* Number of errors */
   struct symbol *errsym;   /* The error symbol */
@@ -3020,6 +3026,27 @@ PRIVATE FILE *file_open(
   return fp;
 }
 
+/* Print the text of a rule
+*/
+void rule_print(FILE *out, struct rule *rp){
+  int i, j;
+  fprintf(out, "%s",rp->lhs->name);
+  /*    if( rp->lhsalias ) fprintf(out,"(%s)",rp->lhsalias); */
+  fprintf(out," ::=");
+  for(i=0; i<rp->nrhs; i++){
+    struct symbol *sp = rp->rhs[i];
+    if( sp->type==MULTITERMINAL ){
+      fprintf(out," %s", sp->subsym[0]->name);
+      for(j=1; j<sp->nsubsym; j++){
+        fprintf(out,"|%s", sp->subsym[j]->name);
+      }
+    }else{
+      fprintf(out," %s", sp->name);
+    }
+    /* if( rp->rhsalias[i] ) fprintf(out,"(%s)",rp->rhsalias[i]); */
+  }
+}
+
 /* Duplicate the input file without comments and without actions
 ** on rules */
 void Reprint(struct lemon *lemp)
@@ -3047,21 +3074,7 @@ void Reprint(struct lemon *lemp)
     printf("\n");
   }
   for(rp=lemp->rule; rp; rp=rp->next){
-    printf("%s",rp->lhs->name);
-    /*    if( rp->lhsalias ) printf("(%s)",rp->lhsalias); */
-    printf(" ::=");
-    for(i=0; i<rp->nrhs; i++){
-      sp = rp->rhs[i];
-      if( sp->type==MULTITERMINAL ){
-        printf(" %s", sp->subsym[0]->name);
-        for(j=1; j<sp->nsubsym; j++){
-          printf("|%s", sp->subsym[j]->name);
-        }
-      }else{
-        printf(" %s", sp->name);
-      }
-      /* if( rp->rhsalias[i] ) printf("(%s)",rp->rhsalias[i]); */
-    }
+    rule_print(stdout, rp);
     printf(".");
     if( rp->precsym ) printf(" [%s]",rp->precsym->name);
     /* if( rp->code ) printf("\n    %s",rp->code); */
@@ -3321,16 +3334,19 @@ PRIVATE int compute_action(struct lemon *lemp, struct action *ap)
   switch( ap->type ){
     case SHIFT:  act = ap->x.stp->statenum;                        break;
     case SHIFTREDUCE: {
-      act = ap->x.rp->iRule + lemp->nstate;
       /* Since a SHIFT is inherient after a prior REDUCE, convert any
       ** SHIFTREDUCE action with a nonterminal on the LHS into a simple
       ** REDUCE action: */
-      if( ap->sp->index>=lemp->nterminal ) act += lemp->nrule;
+      if( ap->sp->index>=lemp->nterminal ){
+        act = lemp->minReduce + ap->x.rp->iRule;
+      }else{
+        act = lemp->minShiftReduce + ap->x.rp->iRule;
+      }
       break;
     }
-    case REDUCE: act = ap->x.rp->iRule + lemp->nstate+lemp->nrule; break;
-    case ERROR:  act = lemp->nstate + lemp->nrule*2;               break;
-    case ACCEPT: act = lemp->nstate + lemp->nrule*2 + 1;           break;
+    case REDUCE: act = lemp->minReduce + ap->x.rp->iRule;          break;
+    case ERROR:  act = lemp->errAction;                            break;
+    case ACCEPT: act = lemp->accAction;                            break;
     default:     act = -1; break;
   }
   return act;
@@ -4038,6 +4054,13 @@ void ReportTable(
   int mnNtOfst, mxNtOfst;
   struct axset *ax;
 
+  lemp->minShiftReduce = lemp->nstate;
+  lemp->errAction = lemp->minShiftReduce + lemp->nrule;
+  lemp->accAction = lemp->errAction + 1;
+  lemp->noAction = lemp->accAction + 1;
+  lemp->minReduce = lemp->noAction + 1;
+  lemp->maxAction = lemp->minReduce + lemp->nrule;
+
   in = tplt_open(lemp);
   if( in==0 ) return;
   out = file_open(lemp,".c","wb");
@@ -4076,7 +4099,7 @@ void ReportTable(
     minimum_size_type(0, lemp->nsymbol+1, &szCodeType)); lineno++;
   fprintf(out,"#define YYNOCODE %d\n",lemp->nsymbol+1);  lineno++;
   fprintf(out,"#define YYACTIONTYPE %s\n",
-    minimum_size_type(0,lemp->nstate+lemp->nrule*2+5,&szActionType)); lineno++;
+    minimum_size_type(0,lemp->maxAction,&szActionType)); lineno++;
   if( lemp->wildcard ){
     fprintf(out,"#define YYWILDCARD %d\n",
        lemp->wildcard->index); lineno++;
@@ -4201,15 +4224,16 @@ void ReportTable(
   fprintf(out,"#define YYNSTATE             %d\n",lemp->nxstate);  lineno++;
   fprintf(out,"#define YYNRULE              %d\n",lemp->nrule);  lineno++;
   fprintf(out,"#define YY_MAX_SHIFT         %d\n",lemp->nxstate-1); lineno++;
-  fprintf(out,"#define YY_MIN_SHIFTREDUCE   %d\n",lemp->nstate); lineno++;
-  i = lemp->nstate + lemp->nrule;
+  i = lemp->minShiftReduce;
+  fprintf(out,"#define YY_MIN_SHIFTREDUCE   %d\n",i); lineno++;
+  i += lemp->nrule;
   fprintf(out,"#define YY_MAX_SHIFTREDUCE   %d\n", i-1); lineno++;
-  fprintf(out,"#define YY_MIN_REDUCE        %d\n", i); lineno++;
-  i = lemp->nstate + lemp->nrule*2;
+  fprintf(out,"#define YY_ERROR_ACTION      %d\n", lemp->errAction); lineno++;
+  fprintf(out,"#define YY_ACCEPT_ACTION     %d\n", lemp->accAction); lineno++;
+  fprintf(out,"#define YY_NO_ACTION         %d\n", lemp->noAction); lineno++;
+  fprintf(out,"#define YY_MIN_REDUCE        %d\n", lemp->minReduce); lineno++;
+  i = lemp->minReduce + lemp->nrule;
   fprintf(out,"#define YY_MAX_REDUCE        %d\n", i-1); lineno++;
-  fprintf(out,"#define YY_ERROR_ACTION      %d\n", i); lineno++;
-  fprintf(out,"#define YY_ACCEPT_ACTION     %d\n", i+1); lineno++;
-  fprintf(out,"#define YY_NO_ACTION         %d\n", i+2); lineno++;
   tplt_xfer(lemp->name,in,out,&lineno);
 
   /* Now output the action table and its associates:
@@ -4231,7 +4255,7 @@ void ReportTable(
   fprintf(out,"static const YYACTIONTYPE yy_action[] = {\n"); lineno++;
   for(i=j=0; i<n; i++){
     int action = acttab_yyaction(pActtab, i);
-    if( action<0 ) action = lemp->nstate + lemp->nrule + 2;
+    if( action<0 ) action = lemp->noAction;
     if( j==0 ) fprintf(out," /* %5d */ ", i);
     fprintf(out, " %4d,", action);
     if( j==9 || i==n-1 ){
@@ -4320,7 +4344,11 @@ void ReportTable(
   for(i=j=0; i<n; i++){
     stp = lemp->sorted[i];
     if( j==0 ) fprintf(out," /* %5d */ ", i);
-    fprintf(out, " %4d,", stp->iDfltReduce+lemp->nstate+lemp->nrule);
+    if( stp->iDfltReduce<0 ){
+      fprintf(out, " %4d,", lemp->errAction);
+    }else{
+      fprintf(out, " %4d,", stp->iDfltReduce + lemp->minReduce);
+    }
     if( j==9 || i==n-1 ){
       fprintf(out, "\n"); lineno++;
       j = 0;
@@ -4401,7 +4429,7 @@ void ReportTable(
       if( sp==0 || sp->type==TERMINAL ||
           sp->index<=0 || sp->destructor!=0 ) continue;
       if( once ){
-        fprintf(out, "      /* Default NON-TERMINAL Destructor */\n"); lineno++;
+        fprintf(out, "      /* Default NON-TERMINAL Destructor */\n");lineno++;
         once = 0;
       }
       fprintf(out,"    case %d: /* %s */\n", sp->index, sp->name); lineno++;
@@ -4444,8 +4472,10 @@ void ReportTable(
   ** Note: This code depends on the fact that rules are number
   ** sequentually beginning with 0.
   */
-  for(rp=lemp->rule; rp; rp=rp->next){
-    fprintf(out,"  { %d, %d },\n",rp->lhs->index,-rp->nrhs); lineno++;
+  for(i=0, rp=lemp->rule; rp; rp=rp->next, i++){
+    fprintf(out,"  { %4d, %4d }, /* (%d) ",rp->lhs->index,-rp->nrhs,i);
+    rule_print(out, rp);
+    fprintf(out," */\n"); lineno++;
   }
   tplt_xfer(lemp->name,in,out,&lineno);
 
@@ -4711,7 +4741,7 @@ void ResortStates(struct lemon *lemp)
   for(i=0; i<lemp->nstate; i++){
     stp = lemp->sorted[i];
     stp->nTknAct = stp->nNtAct = 0;
-    stp->iDfltReduce = lemp->nrule;  /* Init dflt action to "syntax error" */
+    stp->iDfltReduce = -1; /* Init dflt action to "syntax error" */
     stp->iTknOfst = NO_OFFSET;
     stp->iNtOfst = NO_OFFSET;
     for(ap=stp->ap; ap; ap=ap->next){
@@ -4723,7 +4753,7 @@ void ResortStates(struct lemon *lemp)
           stp->nNtAct++;
         }else{
           assert( stp->autoReduce==0 || stp->pDfltReduce==ap->x.rp );
-          stp->iDfltReduce = iAction - lemp->nstate - lemp->nrule;
+          stp->iDfltReduce = iAction;
         }
       }
     }

diff --git a/tool/lempar.c b/tool/lempar.c
index 89c1c80f70fdae53c7e0e84336b26142a1c3f1bd..7d25175ca7372c1b5539412e60296b3f6f3f4689 100644 (file)
--- a/tool/lempar.c
+++ b/tool/lempar.c
@@ -75,11 +75,11 @@
 **    YY_MAX_SHIFT       Maximum value for shift actions
 **    YY_MIN_SHIFTREDUCE Minimum value for shift-reduce actions
 **    YY_MAX_SHIFTREDUCE Maximum value for shift-reduce actions
-**    YY_MIN_REDUCE      Minimum value for reduce actions
-**    YY_MAX_REDUCE      Maximum value for reduce actions
 **    YY_ERROR_ACTION    The yy_action[] code for syntax error
 **    YY_ACCEPT_ACTION   The yy_action[] code for accept
 **    YY_NO_ACTION       The yy_action[] code for no-op
+**    YY_MIN_REDUCE      Minimum value for reduce actions
+**    YY_MAX_REDUCE      Maximum value for reduce actions
 */
 #ifndef INTERFACE
 # define INTERFACE 1
@@ -115,9 +115,6 @@
 **   N between YY_MIN_SHIFTREDUCE       Shift to an arbitrary state then
 **     and YY_MAX_SHIFTREDUCE           reduce by rule N-YY_MIN_SHIFTREDUCE.
 **
-**   N between YY_MIN_REDUCE            Reduce by rule N-YY_MIN_REDUCE
-**     and YY_MAX_REDUCE
-**
 **   N == YY_ERROR_ACTION               A syntax error has occurred.
 **
 **   N == YY_ACCEPT_ACTION              The parser accepts its input.
@@ -125,6 +122,9 @@
 **   N == YY_NO_ACTION                  No such action.  Denotes unused
 **                                      slots in the yy_action[] table.
 **
+**   N between YY_MIN_REDUCE            Reduce by rule N-YY_MIN_REDUCE
+**     and YY_MAX_REDUCE
+**
 ** The action table is constructed as a single large table named yy_action[].
 ** Given state S and lookahead X, the action is computed as either:
 **
@@ -868,14 +868,14 @@ void Parse(
 
   do{
     yyact = yy_find_shift_action(yypParser,(YYCODETYPE)yymajor);
-    if( yyact <= YY_MAX_SHIFTREDUCE ){
+    if( yyact >= YY_MIN_REDUCE ){
+      yy_reduce(yypParser,yyact-YY_MIN_REDUCE,yymajor,yyminor);
+    }else if( yyact <= YY_MAX_SHIFTREDUCE ){
       yy_shift(yypParser,yyact,yymajor,yyminor);
 #ifndef YYNOERRORRECOVERY
       yypParser->yyerrcnt--;
 #endif
       yymajor = YYNOCODE;
-    }else if( yyact <= YY_MAX_REDUCE ){
-      yy_reduce(yypParser,yyact-YY_MIN_REDUCE,yymajor,yyminor);
     }else{
       assert( yyact == YY_ERROR_ACTION );
       yyminorunion.yy0 = yyminor;