void EliminateUnitReductions( void )
/**********************************/
{
unsigned sum;
a_word *reduce_set;
int i;
sum = 0;
do {
changeOccurred = 0;
for( i = 0; i < nstate; ++i ) {
tossSingleReduceStates( statetab[i] );
}
sum += changeOccurred;
} while( changeOccurred );
reduce_set = AllocSet( 1 );
do {
changeOccurred = 0;
for( i = 0; i < nstate; ++i ) {
tryElimination( statetab[i], reduce_set );
}
sum += changeOccurred;
} while( changeOccurred );
FREE( reduce_set );
dumpstatistic( "unit reduction states removed", deadStates );
dumpstatistic( "unit reduction optimizations", sum );
}
int main( int argc, char **argv )
{
int i;
FILE *skeleton, *temp, *tokout, *actout;
int ch;
char tempfname[10];
char *fileprefix = "y";
size_t size;
param_requested = 0;
for( i = 1; i < argc; ++i ) {
ch = argv[i][0];
switch( param_requested ) {
case 'b':
if( ch != '-' ) {
if( ch != '\0' )
fileprefix = argv[i];
++i;
}
break;
case 'p':
if( ch != '-' ) {
if( ch != '\0' )
symprefix = argv[i];
++i;
}
break;
default:
break;
}
param_requested = 0;
if( argv[i][0] != '-' )
break;
setoptions( &argv[i][1] );
}
if( i != argc - 1 && i != argc - 2 ) {
puts( "usage: yacc [-dlv] [-d[bcdfhpstuw]] [-b <file_prefix>] [-p <sym_prefix>]" );
puts( " <grammar> [<driver>]" );
puts( "options:" );
puts( " -b <file_prefix> file prefix used in place of default 'y' prefix" );
puts( " -d output header file" );
puts( " -db output bigger (less optimal) tables" );
puts( " -dc output compact tables (slower to execute)" );
puts( " -dd use dense tokens (no '+' style tokens allowed)" );
puts( " -de dump all symbols to header file as enum items, no macros" );
puts( " -df output fast tables (larger size)" );
puts( " -dh use 'default shift' optimization" );
puts( " -dp dump all productions" );
puts( " -ds dump full state tables" );
puts( " -dt translate 'keyword' to Y_KEYWORD, '++' to Y_PLUS_PLUS, etc." );
puts( " -du eliminate useless unit production reduction" );
puts( " -dw disable default action type checking" );
puts( " -l output #line directives" );
puts( " -p <sym_prefix> symbol prefix used in place of default 'yy' prefix" );
puts( " -v write description and report into file" );
exit( 1 );
}
skeleton = NULL;
if( i == argc - 2 ) {
skeleton = openr( argv[argc - 1] );
if( skeleton == NULL ) {
msg( "could not open driver source code '%s'\n", argv[argc - 1] );
}
}
loadpath = argv[0];
*getname( loadpath ) = '\0';
srcname = argv[i];
if( !strrchr( srcname, '.' ) ) {
srcname = alloca( strlen( argv[i] )+3 );
srcname = strcat( strcpy( srcname, argv[i] ), ".y" );
}
yaccin = openr( srcname );
size = strlen( fileprefix);
codefilename = MALLOC( size + 6, char );
strcat( strcpy( codefilename, fileprefix), "tab.c" );
headerfilename = MALLOC( size + 6, char );
strcat( strcpy( headerfilename, fileprefix), "tab.h" );
descfilename = MALLOC( size + 5, char );
strcat( strcpy( descfilename, fileprefix), ".out" );
actout = openw( codefilename );
defs( actout );
tokout = openw( headerfilename );
dump_header( tokout );
temp = NULL;
for( i = 0; i < 1000 && temp == NULL; ++i ) {
sprintf( tempfname, "ytab.%3d", i );
temp = fopen( tempfname, "w+" );
}
if( temp == NULL ) {
msg( "Cannot create temporary file\n" );
}
rules( temp );
buildpro();
CalcMinSentence();
if( proflag || showflag ) {
showpro();
}
lr0();
lalr1();
SetupStateTable();
/* apply state filters */
FindUnused();
if( eliminateunitflag ) {
EliminateUnitReductions();
}
if( default_shiftflag ) {
if( keyword_id_low == 0 ) {
msg( "No %%keyword_id <low> <high> specified." );
} else {
MarkDefaultShifts();
}
}
MarkNoUnitRuleOptimizationStates();
RemoveDeadStates();
MarkDefaultReductions();
if( showflag ) {
showstates();
}
if( warnings ) {
if( warnings == 1 ) {
printf( "%s: 1 warning\n", srcname );
} else {
printf( "%s: %d warnings\n", srcname, warnings );
}
exit( 1 );
}
parsestats();
dumpstatistic( "parser states", nstate );
dumpstatistic( "# states (1 reduce only)", nstate_1_reduce );
dumpstatistic( "reduce/reduce conflicts", RR_conflicts );
dumpstatistic( "shift/reduce conflicts", SR_conflicts );
show_unused();
if( skeleton == NULL ) {
skeleton = fpopen( loadpath, "yydriver.c" );
if( skeleton == NULL ) {
warn( "Can't find yacc skeleton yydriver.c\n" );
}
}
/* copy first part of skeleton */
if( skeleton != NULL )
copy_part( skeleton, actout );
rewind( tokout );
/* copy tokens */
copy_rest( tokout, actout );
close_header( tokout );
genobj( actout );
/* copy middle part of skeleton */
if( skeleton != NULL )
copy_part( skeleton, actout );
rewind( temp );
copy_rest( temp, actout );
fclose( temp );
remove( tempfname );
/* copy last part of skeleton */
if( skeleton != NULL ) {
copy_rest( skeleton, actout );
fclose( skeleton );
}
tail( actout );
fclose( actout );
FREE( codefilename );
FREE( headerfilename );
FREE( descfilename );
return( 0 );
}
void genobj( void )
{
value_size token_size;
action_n *actions, *parent, *other;
base_n *base;
token_n *p, *q, *r, *s;
token_n *tokens, *same, *diff, *test, *best;
set_size *mp;
token_n tokval, dtoken, ptoken, ntoken;
action_n actval, error, redun, new_action;
a_sym *sym;
a_pro *pro;
an_item *item;
a_state *x;
a_shift_action *tx;
a_reduce_action *rx;
index_n i, j;
set_size savings, min, *size;
set_size shift;
token_n parent_base;
unsigned num_default, num_parent;
if( fastflag ) {
GenFastTables();
return;
}
if( bigflag || compactflag ) {
token_size = FITS_A_WORD;
} else {
token_size = FITS_A_BYTE;
}
num_default = 0;
num_parent = 0;
ntoken = FirstNonTerminalTokenValue();
dtoken = ntoken++;
ptoken = ntoken++;
for( i = nterm; i < nsym; ++i ) {
symtab[i]->token = ntoken++;
}
actions = CALLOC( ntoken, action_n );
error = nstate + npro;
for( i = 0; i < ntoken; ++i ) {
actions[i] = error;
}
tokens = CALLOC( ntoken, token_n );
test = CALLOC( ntoken, token_n );
best = CALLOC( ntoken, token_n );
other = CALLOC( nstate, action_n );
parent = CALLOC( nstate, action_n );
size = CALLOC( nstate, set_size );
base = CALLOC( nstate, base_n );
same = NULL;
r = NULL;
diff = NULL;
used = 0;
avail = 0;
table = NULL;
shift = 0;
parent_base = 0;
for( i = nstate; i > 0; ) {
--i;
x = statetab[i];
q = tokens;
for( tx = x->trans; (sym = tx->sym) != NULL; ++tx ) {
*q++ = sym->token;
actions[sym->token] = tx->state->sidx;
}
savings = 0;
for( rx = x->redun; (pro = rx->pro) != NULL; ++rx ) {
redun = pro->pidx + nstate;
mp = Members( rx->follow );
if( (set_size)( mp - setmembers ) > savings ) {
savings = (set_size)( mp - setmembers );
r = q;
}
while( mp != setmembers ) {
--mp;
tokval = symtab[*mp]->token;
*q++ = tokval;
actions[tokval] = redun;
}
}
if( savings ) {
actval = actions[*r];
other[i] = actval;
*q++ = dtoken;
actions[dtoken] = actval;
p = r;
while( savings-- > 0 )
actions[*p++] = error;
while( p < q )
*r++ = *p++;
q = r;
++num_default;
} else {
other[i] = error;
}
r = q;
min = (set_size)( q - tokens );
size[i] = min;
parent[i] = nstate;
for( j = nstate; --j > i; ) {
if( abs( size[j] - size[i] ) < min ) {
x = statetab[j];
p = test;
q = test + ntoken;
for( tx = x->trans; (sym = tx->sym) != NULL; ++tx ) {
if( actions[sym->token] == tx->state->sidx ) {
*p++ = sym->token;
} else {
*--q = sym->token;
}
}
for( rx = x->redun; (pro = rx->pro) != NULL; ++rx ) {
redun = pro->pidx + nstate;
if( redun == other[j] )
redun = error;
for( mp = Members( rx->follow ); mp != setmembers; ) {
--mp;
tokval = symtab[*mp]->token;
if( actions[tokval] == redun ) {
*p++ = tokval;
} else {
*--q = tokval;
}
}
}
if( other[j] != error ) {
if( other[j] == other[i] ) {
*p++ = dtoken;
} else {
*--q = dtoken;
}
}
savings = (set_size)( size[i] + size[j] - 2 * ( p - test ) );
if( savings < min ) {
min = savings;
same = p;
diff = q;
s = test; test = best; best = s;
parent[i] = j;
}
}
}
if( min >= size[i] ) {
s = r;
} else {
++num_parent;
s = tokens;
p = same;
while( --p >= best )
actions[*p] = error;
for( q = tokens; q < r; ++q ) {
if( actions[*q] != error ) {
*s++ = *q;
}
}
p = best + ntoken;
while( --p >= diff ) {
if( actions[*p] == error ) {
*s++ = *p;
}
}
actval = parent[i];
*s++ = ptoken;
actions[ptoken] = actval;
}
base[i] = addtotable( tokens, s, actions, dtoken, ptoken );
while( --s >= tokens ) {
actions[*s] = error;
}
}
FREE( actions );
FREE( tokens );
FREE( test );
FREE( best );
FREE( other );
FREE( size );
putambigs( base );
putnum( "YYNOACTION", error - nstate + used );
putnum( "YYEOFTOKEN", eofsym->token );
putnum( "YYERRTOKEN", errsym->token );
putnum( "YYETOKEN", errsym->token );
if( compactflag ) {
parent_base = used + npro;
putnum( "YYPARENT", parent_base );
shift = 8;
for( i = 256; i < used; i <<= 1 ) {
++shift;
}
putnum( "YYPRODSIZE", shift );
} else {
putnum( "YYPTOKEN", ptoken );
putnum( "YYDTOKEN", dtoken );
}
putnum( "YYSTART", base[startstate->sidx] );
putnum( "YYSTOP", base[eofsym->enter->sidx] );
putnum( "YYERR", base[errstate->sidx] );
putnum( "YYUSED", used );
if( compactflag ) {
begtab( "YYPACKTYPE", "yyacttab" );
j = nstate;
for( i = 0; i < used; ++i ) {
new_action = table[i].action;
if( i == base[j - 1] ) {
--j;
// First element in each state is default/parent
if( parent[j] == nstate ) {
// No parent state
tokval = used + parent_base;
} else {
tokval = base[parent[j]] + parent_base;
}
// 0 indicates no default
if( new_action != 0 ) {
if( new_action < nstate ) {
// Shift
new_action = base[new_action];
} else {
// Reduce
new_action -= nstate; // convert to 0 based
new_action += used; // now convert to 'used' base
}
}
} else {
tokval = table[i].token;
if( new_action < nstate ) {
// Shift
new_action = base[new_action];
} else {
// Reduce
new_action -= nstate; // convert to 0 based
new_action += used; // now convert to 'used' base
}
}
putcompact( tokval, new_action );
}
endtab();
// Combine lengths & lhs into a single table
begtab( "YYPRODTYPE", "yyprodtab" );
for( i = 0; i < npro; ++i ) {
j = 0;
for( item = protab[i]->items; item->p.sym != NULL; ++item ) {
++j;
}
puttab( FITS_A_WORD, (j << shift) + protab[i]->sym->token );
}
endtab();
} else {
begtab( "YYCHKTYPE", "yychktab" );
for( i = 0; i < used; ++i ) {
puttab( token_size, Token( table + i ) );
}
endtab();
begtab( "YYACTTYPE", "yyacttab" );
for( i = 0; i < used; ++i ) {
j = Action( table + i );
if( j < nstate ) {
puttab( FITS_A_WORD, base[j] );
} else {
puttab( FITS_A_WORD, j - nstate + used );
}
}
endtab();
begtab( "YYPLENTYPE", "yyplentab" );
for( i = 0; i < npro; ++i ) {
for( item = protab[i]->items; item->p.sym != NULL; ) {
++item;
}
puttab( FITS_A_BYTE, (unsigned)( item - protab[i]->items ) );
}
endtab();
begtab( "YYPLHSTYPE", "yyplhstab" );
for( i = 0; i < npro; ++i ) {
puttab( token_size, protab[i]->sym->token );
}
endtab();
}
FREE( table );
FREE( base );
FREE( parent );
dumpstatistic( "bytes used in tables", bytesused );
dumpstatistic( "states with defaults", num_default );
dumpstatistic( "states with parents", num_parent );
puttokennames( dtoken, token_size );
FREE( protab );
FREE( symtab );
}
