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Overview
Comment:Enhancements to lemon to generate more compact action tables and to avoid making array bounds tests that can never fail on action table calculations.
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SHA1:27d8e684db4651155c4bcb8bb44bf1c692b8c48b
User & Date: drh 2009-11-03 19:18:32
Context
2009-11-03
19:42
Fix compiler warnings on MSVC build. check-in: 01c4b5b8 user: shane tags: trunk
19:18
Enhancements to lemon to generate more compact action tables and to avoid making array bounds tests that can never fail on action table calculations. check-in: 27d8e684 user: drh tags: trunk
13:08
Force all qsort() calls in mkkeywordhash.c to be stable so that we get predictable results on different platforms. check-in: 3b02df27 user: drh tags: trunk
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to src/lempar.c.

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**  yy_shift_ofst[]    For each state, the offset into yy_action for
**                     shifting terminals.
**  yy_reduce_ofst[]   For each state, the offset into yy_action for
**                     shifting non-terminals after a reduce.
**  yy_default[]       Default action for each state.
*/
%%
#define YY_SZ_ACTTAB (int)(sizeof(yy_action)/sizeof(yy_action[0]))

/* The next table maps tokens into fallback tokens.  If a construct
** like the following:
** 
**      %fallback ID X Y Z.
**
** appears in the grammar, then ID becomes a fallback token for X, Y,
................................................................................
static int yy_find_shift_action(
  yyParser *pParser,        /* The parser */
  YYCODETYPE iLookAhead     /* The look-ahead token */
){
  int i;
  int stateno = pParser->yystack[pParser->yyidx].stateno;
 

  if( stateno>YY_SHIFT_MAX || (i = yy_shift_ofst[stateno])==YY_SHIFT_USE_DFLT ){
    return yy_default[stateno];
  }
  assert( iLookAhead!=YYNOCODE );
  i += iLookAhead;
  if( i<0 || i>=YY_SZ_ACTTAB || yy_lookahead[i]!=iLookAhead ){
    /* The user of ";" instead of "\000" as a statement terminator in SQLite
    ** means that we always have a look-ahead token. */
    if( iLookAhead>0 ){
#ifdef YYFALLBACK
      YYCODETYPE iFallback;            /* Fallback token */
      if( iLookAhead<sizeof(yyFallback)/sizeof(yyFallback[0])
             && (iFallback = yyFallback[iLookAhead])!=0 ){
#ifndef NDEBUG
        if( yyTraceFILE ){
................................................................................
#endif
        return yy_find_shift_action(pParser, iFallback);
      }
#endif
#ifdef YYWILDCARD
      {
        int j = i - iLookAhead + YYWILDCARD;







        if( j>=0 && j<YY_SZ_ACTTAB && yy_lookahead[j]==YYWILDCARD ){

#ifndef NDEBUG
          if( yyTraceFILE ){
            fprintf(yyTraceFILE, "%sWILDCARD %s => %s\n",
               yyTracePrompt, yyTokenName[iLookAhead], yyTokenName[YYWILDCARD]);
          }
#endif /* NDEBUG */
          return yy_action[j];
................................................................................
*/
static int yy_find_reduce_action(
  int stateno,              /* Current state number */
  YYCODETYPE iLookAhead     /* The look-ahead token */
){
  int i;
#ifdef YYERRORSYMBOL
  if( stateno>YY_REDUCE_MAX ){
    return yy_default[stateno];
  }
#else
  assert( stateno<=YY_REDUCE_MAX );
#endif
  i = yy_reduce_ofst[stateno];
  assert( i!=YY_REDUCE_USE_DFLT );
  assert( iLookAhead!=YYNOCODE );
  i += iLookAhead;
#ifdef YYERRORSYMBOL
  if( i<0 || i>=YY_SZ_ACTTAB || yy_lookahead[i]!=iLookAhead ){
    return yy_default[stateno];
  }
#else
  assert( i>=0 && i<YY_SZ_ACTTAB );
  assert( yy_lookahead[i]==iLookAhead );
#endif
  return yy_action[i];
}

/*
** The following routine is called if the stack overflows.







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**  yy_shift_ofst[]    For each state, the offset into yy_action for
**                     shifting terminals.
**  yy_reduce_ofst[]   For each state, the offset into yy_action for
**                     shifting non-terminals after a reduce.
**  yy_default[]       Default action for each state.
*/
%%


/* The next table maps tokens into fallback tokens.  If a construct
** like the following:
** 
**      %fallback ID X Y Z.
**
** appears in the grammar, then ID becomes a fallback token for X, Y,
................................................................................
static int yy_find_shift_action(
  yyParser *pParser,        /* The parser */
  YYCODETYPE iLookAhead     /* The look-ahead token */
){
  int i;
  int stateno = pParser->yystack[pParser->yyidx].stateno;
 
  if( stateno>YY_SHIFT_COUNT
   || (i = yy_shift_ofst[stateno])==YY_SHIFT_USE_DFLT ){
    return yy_default[stateno];
  }
  assert( iLookAhead!=YYNOCODE );
  i += iLookAhead;
  if( i<0 || i>=YY_ACTTAB_COUNT || yy_lookahead[i]!=iLookAhead ){


    if( iLookAhead>0 ){
#ifdef YYFALLBACK
      YYCODETYPE iFallback;            /* Fallback token */
      if( iLookAhead<sizeof(yyFallback)/sizeof(yyFallback[0])
             && (iFallback = yyFallback[iLookAhead])!=0 ){
#ifndef NDEBUG
        if( yyTraceFILE ){
................................................................................
#endif
        return yy_find_shift_action(pParser, iFallback);
      }
#endif
#ifdef YYWILDCARD
      {
        int j = i - iLookAhead + YYWILDCARD;
        if( 
#if YY_SHIFT_MIN+YYWILDCARD<0
          j>=0 &&
#endif
#if YY_SHIFT_MAX+YYWILDCARD>=YY_ACTTAB_COUNT
          j<YY_ACTTAB_COUNT &&
#endif
          yy_lookahead[j]==YYWILDCARD
        ){
#ifndef NDEBUG
          if( yyTraceFILE ){
            fprintf(yyTraceFILE, "%sWILDCARD %s => %s\n",
               yyTracePrompt, yyTokenName[iLookAhead], yyTokenName[YYWILDCARD]);
          }
#endif /* NDEBUG */
          return yy_action[j];
................................................................................
*/
static int yy_find_reduce_action(
  int stateno,              /* Current state number */
  YYCODETYPE iLookAhead     /* The look-ahead token */
){
  int i;
#ifdef YYERRORSYMBOL
  if( stateno>YY_REDUCE_COUNT ){
    return yy_default[stateno];
  }
#else
  assert( stateno<=YY_REDUCE_COUNT );
#endif
  i = yy_reduce_ofst[stateno];
  assert( i!=YY_REDUCE_USE_DFLT );
  assert( iLookAhead!=YYNOCODE );
  i += iLookAhead;
#ifdef YYERRORSYMBOL
  if( i<0 || i>=YY_ACTTAB_COUNT || yy_lookahead[i]!=iLookAhead ){
    return yy_default[stateno];
  }
#else
  assert( i>=0 && i<YY_ACTTAB_COUNT );
  assert( yy_lookahead[i]==iLookAhead );
#endif
  return yy_action[i];
}

/*
** The following routine is called if the stack overflows.

Changes to tool/lemon.c.

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  /* Scan the existing action table looking for an offset where we can
  ** insert the current transaction set.  Fall out of the loop when that
  ** offset is found.  In the worst case, we fall out of the loop when
  ** i reaches p->nAction, which means we append the new transaction set.
  **
  ** i is the index in p->aAction[] where p->mnLookahead is inserted.
  */
  for(i=0; i<p->nAction+p->mnLookahead; i++){
    if( p->aAction[i].lookahead<0 ){
      for(j=0; j<p->nLookahead; j++){
        k = p->aLookahead[j].lookahead - p->mnLookahead + i;
        if( k<0 ) break;
        if( p->aAction[k].lookahead>=0 ) break;
      }
      if( j<p->nLookahead ) continue;
      for(j=0; j<p->nAction; j++){
        if( p->aAction[j].lookahead==j+p->mnLookahead-i ) break;
      }
      if( j==p->nAction ){
        break;  /* Fits in empty slots */
      }

    }else if( p->aAction[i].lookahead==p->mnLookahead ){
      if( p->aAction[i].action!=p->mnAction ) continue;
      for(j=0; j<p->nLookahead; j++){
        k = p->aLookahead[j].lookahead - p->mnLookahead + i;
        if( k<0 || k>=p->nAction ) break;
        if( p->aLookahead[j].lookahead!=p->aAction[k].lookahead ) break;
        if( p->aLookahead[j].action!=p->aAction[k].action ) break;
      }
................................................................................
        if( p->aAction[j].lookahead<0 ) continue;
        if( p->aAction[j].lookahead==j+p->mnLookahead-i ) n++;
      }
      if( n==p->nLookahead ){
        break;  /* Same as a prior transaction set */
      }
    }



















  }
  /* Insert transaction set at index i. */
  for(j=0; j<p->nLookahead; j++){
    k = p->aLookahead[j].lookahead - p->mnLookahead + i;
    p->aAction[k] = p->aLookahead[j];
    if( k>=p->nAction ) p->nAction = k+1;
  }
................................................................................
  FILE *out, *in;
  char line[LINESIZE];
  int  lineno;
  struct state *stp;
  struct action *ap;
  struct rule *rp;
  struct acttab *pActtab;
  int i, j, n;
  char *name;
  int mnTknOfst, mxTknOfst;
  int mnNtOfst, mxNtOfst;
  struct axset *ax;

  in = tplt_open(lemp);
  if( in==0 ) return;
................................................................................
      if( stp->iNtOfst<mnNtOfst ) mnNtOfst = stp->iNtOfst;
      if( stp->iNtOfst>mxNtOfst ) mxNtOfst = stp->iNtOfst;
    }
  }
  free(ax);

  /* Output the yy_action table */
  fprintf(out,"static const YYACTIONTYPE yy_action[] = {\n"); lineno++;
  n = acttab_size(pActtab);


  for(i=j=0; i<n; i++){
    int action = acttab_yyaction(pActtab, i);
    if( action<0 ) action = lemp->nstate + lemp->nrule + 2;
    if( j==0 ) fprintf(out," /* %5d */ ", i);
    fprintf(out, " %4d,", action);
    if( j==9 || i==n-1 ){
      fprintf(out, "\n"); lineno++;
................................................................................
  }
  fprintf(out, "};\n"); lineno++;

  /* Output the yy_shift_ofst[] table */
  fprintf(out, "#define YY_SHIFT_USE_DFLT (%d)\n", mnTknOfst-1); lineno++;
  n = lemp->nstate;
  while( n>0 && lemp->sorted[n-1]->iTknOfst==NO_OFFSET ) n--;


  fprintf(out, "#define YY_SHIFT_MAX %d\n", n-1); lineno++;
  fprintf(out, "static const %s yy_shift_ofst[] = {\n", 
          minimum_size_type(mnTknOfst-1, mxTknOfst)); lineno++;
  for(i=j=0; i<n; i++){
    int ofst;
    stp = lemp->sorted[i];
    ofst = stp->iTknOfst;
    if( ofst==NO_OFFSET ) ofst = mnTknOfst - 1;
................................................................................
  }
  fprintf(out, "};\n"); lineno++;

  /* Output the yy_reduce_ofst[] table */
  fprintf(out, "#define YY_REDUCE_USE_DFLT (%d)\n", mnNtOfst-1); lineno++;
  n = lemp->nstate;
  while( n>0 && lemp->sorted[n-1]->iNtOfst==NO_OFFSET ) n--;


  fprintf(out, "#define YY_REDUCE_MAX %d\n", n-1); lineno++;
  fprintf(out, "static const %s yy_reduce_ofst[] = {\n", 
          minimum_size_type(mnNtOfst-1, mxNtOfst)); lineno++;
  for(i=j=0; i<n; i++){
    int ofst;
    stp = lemp->sorted[i];
    ofst = stp->iNtOfst;
    if( ofst==NO_OFFSET ) ofst = mnNtOfst - 1;







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  /* Scan the existing action table looking for an offset where we can
  ** insert the current transaction set.  Fall out of the loop when that
  ** offset is found.  In the worst case, we fall out of the loop when
  ** i reaches p->nAction, which means we append the new transaction set.
  **
  ** i is the index in p->aAction[] where p->mnLookahead is inserted.
  */











  for(i=p->nAction-1; i>=0; i--){


    /* First look for an existing action table entry that can be reused */
    if( p->aAction[i].lookahead==p->mnLookahead ){
      if( p->aAction[i].action!=p->mnAction ) continue;
      for(j=0; j<p->nLookahead; j++){
        k = p->aLookahead[j].lookahead - p->mnLookahead + i;
        if( k<0 || k>=p->nAction ) break;
        if( p->aLookahead[j].lookahead!=p->aAction[k].lookahead ) break;
        if( p->aLookahead[j].action!=p->aAction[k].action ) break;
      }
................................................................................
        if( p->aAction[j].lookahead<0 ) continue;
        if( p->aAction[j].lookahead==j+p->mnLookahead-i ) n++;
      }
      if( n==p->nLookahead ){
        break;  /* Same as a prior transaction set */
      }
    }
  }
  if( i<0 ){
    /* If no reusable entry is found, look for an empty slot */
    for(i=0; i<p->nAction; i++){
      if( p->aAction[i].lookahead<0 ){
        for(j=0; j<p->nLookahead; j++){
          k = p->aLookahead[j].lookahead - p->mnLookahead + i;
          if( k<0 ) break;
          if( p->aAction[k].lookahead>=0 ) break;
        }
        if( j<p->nLookahead ) continue;
        for(j=0; j<p->nAction; j++){
          if( p->aAction[j].lookahead==j+p->mnLookahead-i ) break;
        }
        if( j==p->nAction ){
          break;  /* Fits in empty slots */
        }
      }
    }
  }
  /* Insert transaction set at index i. */
  for(j=0; j<p->nLookahead; j++){
    k = p->aLookahead[j].lookahead - p->mnLookahead + i;
    p->aAction[k] = p->aLookahead[j];
    if( k>=p->nAction ) p->nAction = k+1;
  }
................................................................................
  FILE *out, *in;
  char line[LINESIZE];
  int  lineno;
  struct state *stp;
  struct action *ap;
  struct rule *rp;
  struct acttab *pActtab;
  int i, j, k, n;
  char *name;
  int mnTknOfst, mxTknOfst;
  int mnNtOfst, mxNtOfst;
  struct axset *ax;

  in = tplt_open(lemp);
  if( in==0 ) return;
................................................................................
      if( stp->iNtOfst<mnNtOfst ) mnNtOfst = stp->iNtOfst;
      if( stp->iNtOfst>mxNtOfst ) mxNtOfst = stp->iNtOfst;
    }
  }
  free(ax);

  /* Output the yy_action table */

  n = acttab_size(pActtab);
  fprintf(out,"#define YY_ACTTAB_COUNT (%d)\n", n); lineno++;
  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( j==0 ) fprintf(out," /* %5d */ ", i);
    fprintf(out, " %4d,", action);
    if( j==9 || i==n-1 ){
      fprintf(out, "\n"); lineno++;
................................................................................
  }
  fprintf(out, "};\n"); lineno++;

  /* Output the yy_shift_ofst[] table */
  fprintf(out, "#define YY_SHIFT_USE_DFLT (%d)\n", mnTknOfst-1); lineno++;
  n = lemp->nstate;
  while( n>0 && lemp->sorted[n-1]->iTknOfst==NO_OFFSET ) n--;
  fprintf(out, "#define YY_SHIFT_COUNT (%d)\n", n-1); lineno++;
  fprintf(out, "#define YY_SHIFT_MIN   (%d)\n", mnTknOfst); lineno++;
  fprintf(out, "#define YY_SHIFT_MAX   (%d)\n", mxTknOfst); lineno++;
  fprintf(out, "static const %s yy_shift_ofst[] = {\n", 
          minimum_size_type(mnTknOfst-1, mxTknOfst)); lineno++;
  for(i=j=0; i<n; i++){
    int ofst;
    stp = lemp->sorted[i];
    ofst = stp->iTknOfst;
    if( ofst==NO_OFFSET ) ofst = mnTknOfst - 1;
................................................................................
  }
  fprintf(out, "};\n"); lineno++;

  /* Output the yy_reduce_ofst[] table */
  fprintf(out, "#define YY_REDUCE_USE_DFLT (%d)\n", mnNtOfst-1); lineno++;
  n = lemp->nstate;
  while( n>0 && lemp->sorted[n-1]->iNtOfst==NO_OFFSET ) n--;
  fprintf(out, "#define YY_REDUCE_COUNT (%d)\n", n-1); lineno++;
  fprintf(out, "#define YY_REDUCE_MIN   (%d)\n", mnNtOfst); lineno++;
  fprintf(out, "#define YY_REDUCE_MAX   (%d)\n", mxNtOfst); lineno++;
  fprintf(out, "static const %s yy_reduce_ofst[] = {\n", 
          minimum_size_type(mnNtOfst-1, mxNtOfst)); lineno++;
  for(i=j=0; i<n; i++){
    int ofst;
    stp = lemp->sorted[i];
    ofst = stp->iNtOfst;
    if( ofst==NO_OFFSET ) ofst = mnNtOfst - 1;

Changes to tool/lempar.c.

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**  yy_shift_ofst[]    For each state, the offset into yy_action for
**                     shifting terminals.
**  yy_reduce_ofst[]   For each state, the offset into yy_action for
**                     shifting non-terminals after a reduce.
**  yy_default[]       Default action for each state.
*/
%%
#define YY_SZ_ACTTAB (int)(sizeof(yy_action)/sizeof(yy_action[0]))

/* The next table maps tokens into fallback tokens.  If a construct
** like the following:
** 
**      %fallback ID X Y Z.
**
** appears in the grammar, then ID becomes a fallback token for X, Y,
................................................................................
static int yy_find_shift_action(
  yyParser *pParser,        /* The parser */
  YYCODETYPE iLookAhead     /* The look-ahead token */
){
  int i;
  int stateno = pParser->yystack[pParser->yyidx].stateno;
 

  if( stateno>YY_SHIFT_MAX || (i = yy_shift_ofst[stateno])==YY_SHIFT_USE_DFLT ){
    return yy_default[stateno];
  }
  assert( iLookAhead!=YYNOCODE );
  i += iLookAhead;
  if( i<0 || i>=YY_SZ_ACTTAB || yy_lookahead[i]!=iLookAhead ){
    if( iLookAhead>0 ){
#ifdef YYFALLBACK
      YYCODETYPE iFallback;            /* Fallback token */
      if( iLookAhead<sizeof(yyFallback)/sizeof(yyFallback[0])
             && (iFallback = yyFallback[iLookAhead])!=0 ){
#ifndef NDEBUG
        if( yyTraceFILE ){
................................................................................
#endif
        return yy_find_shift_action(pParser, iFallback);
      }
#endif
#ifdef YYWILDCARD
      {
        int j = i - iLookAhead + YYWILDCARD;







        if( j>=0 && j<YY_SZ_ACTTAB && yy_lookahead[j]==YYWILDCARD ){

#ifndef NDEBUG
          if( yyTraceFILE ){
            fprintf(yyTraceFILE, "%sWILDCARD %s => %s\n",
               yyTracePrompt, yyTokenName[iLookAhead], yyTokenName[YYWILDCARD]);
          }
#endif /* NDEBUG */
          return yy_action[j];
................................................................................
*/
static int yy_find_reduce_action(
  int stateno,              /* Current state number */
  YYCODETYPE iLookAhead     /* The look-ahead token */
){
  int i;
#ifdef YYERRORSYMBOL
  if( stateno>YY_REDUCE_MAX ){
    return yy_default[stateno];
  }
#else
  assert( stateno<=YY_REDUCE_MAX );
#endif
  i = yy_reduce_ofst[stateno];
  assert( i!=YY_REDUCE_USE_DFLT );
  assert( iLookAhead!=YYNOCODE );
  i += iLookAhead;
#ifdef YYERRORSYMBOL
  if( i<0 || i>=YY_SZ_ACTTAB || yy_lookahead[i]!=iLookAhead ){
    return yy_default[stateno];
  }
#else
  assert( i>=0 && i<YY_SZ_ACTTAB );
  assert( yy_lookahead[i]==iLookAhead );
#endif
  return yy_action[i];
}

/*
** The following routine is called if the stack overflows.







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128
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...
381
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**  yy_shift_ofst[]    For each state, the offset into yy_action for
**                     shifting terminals.
**  yy_reduce_ofst[]   For each state, the offset into yy_action for
**                     shifting non-terminals after a reduce.
**  yy_default[]       Default action for each state.
*/
%%


/* The next table maps tokens into fallback tokens.  If a construct
** like the following:
** 
**      %fallback ID X Y Z.
**
** appears in the grammar, then ID becomes a fallback token for X, Y,
................................................................................
static int yy_find_shift_action(
  yyParser *pParser,        /* The parser */
  YYCODETYPE iLookAhead     /* The look-ahead token */
){
  int i;
  int stateno = pParser->yystack[pParser->yyidx].stateno;
 
  if( stateno>YY_SHIFT_COUNT
   || (i = yy_shift_ofst[stateno])==YY_SHIFT_USE_DFLT ){
    return yy_default[stateno];
  }
  assert( iLookAhead!=YYNOCODE );
  i += iLookAhead;
  if( i<0 || i>=YY_ACTTAB_COUNT || yy_lookahead[i]!=iLookAhead ){
    if( iLookAhead>0 ){
#ifdef YYFALLBACK
      YYCODETYPE iFallback;            /* Fallback token */
      if( iLookAhead<sizeof(yyFallback)/sizeof(yyFallback[0])
             && (iFallback = yyFallback[iLookAhead])!=0 ){
#ifndef NDEBUG
        if( yyTraceFILE ){
................................................................................
#endif
        return yy_find_shift_action(pParser, iFallback);
      }
#endif
#ifdef YYWILDCARD
      {
        int j = i - iLookAhead + YYWILDCARD;
        if( 
#if YY_SHIFT_MIN+YYWILDCARD<0
          j>=0 &&
#endif
#if YY_SHIFT_MAX+YYWILDCARD>=YY_ACTTAB_COUNT
          j<YY_ACTTAB_COUNT &&
#endif
          yy_lookahead[j]==YYWILDCARD
        ){
#ifndef NDEBUG
          if( yyTraceFILE ){
            fprintf(yyTraceFILE, "%sWILDCARD %s => %s\n",
               yyTracePrompt, yyTokenName[iLookAhead], yyTokenName[YYWILDCARD]);
          }
#endif /* NDEBUG */
          return yy_action[j];
................................................................................
*/
static int yy_find_reduce_action(
  int stateno,              /* Current state number */
  YYCODETYPE iLookAhead     /* The look-ahead token */
){
  int i;
#ifdef YYERRORSYMBOL
  if( stateno>YY_REDUCE_COUNT ){
    return yy_default[stateno];
  }
#else
  assert( stateno<=YY_REDUCE_COUNT );
#endif
  i = yy_reduce_ofst[stateno];
  assert( i!=YY_REDUCE_USE_DFLT );
  assert( iLookAhead!=YYNOCODE );
  i += iLookAhead;
#ifdef YYERRORSYMBOL
  if( i<0 || i>=YY_ACTTAB_COUNT || yy_lookahead[i]!=iLookAhead ){
    return yy_default[stateno];
  }
#else
  assert( i>=0 && i<YY_ACTTAB_COUNT );
  assert( yy_lookahead[i]==iLookAhead );
#endif
  return yy_action[i];
}

/*
** The following routine is called if the stack overflows.