Added Berkeley Yacc sources

util/byacc/mkpar.c

@@ -0,0 +1,371 @@
+#include "defs.h"
+
+action **parser;
+int SRtotal;
+int RRtotal;
+short *SRconflicts;
+short *RRconflicts;
+short *defred;
+short *rules_used;
+short nunused;
+short final_state;
+
+static int SRcount;
+static int RRcount;
+
+extern action *parse_actions();
+extern action *get_shifts();
+extern action *add_reductions();
+extern action *add_reduce();
+
+
+make_parser()
+{
+    register int i;
+
+    parser = NEW2(nstates, action *);
+    for (i = 0; i < nstates; i++)
+	parser[i] = parse_actions(i);
+
+    find_final_state();
+    remove_conflicts();
+    unused_rules();
+    if (SRtotal + RRtotal > 0) total_conflicts();
+    defreds();
+}
+
+
+action *
+parse_actions(stateno)
+register int stateno;
+{
+    register action *actions;
+
+    actions = get_shifts(stateno);
+    actions = add_reductions(stateno, actions);
+    return (actions);
+}
+
+
+action *
+get_shifts(stateno)
+int stateno;
+{
+    register action *actions, *temp;
+    register shifts *sp;
+    register short *to_state;
+    register int i, k;
+    register int symbol;
+
+    actions = 0;
+    sp = shift_table[stateno];
+    if (sp)
+    {
+	to_state = sp->shift;
+	for (i = sp->nshifts - 1; i >= 0; i--)
+	{
+	    k = to_state[i];
+	    symbol = accessing_symbol[k];
+	    if (ISTOKEN(symbol))
+	    {
+		temp = NEW(action);
+		temp->next = actions;
+		temp->symbol = symbol;
+		temp->number = k;
+		temp->prec = symbol_prec[symbol];
+		temp->action_code = SHIFT;
+		temp->assoc = symbol_assoc[symbol];
+		actions = temp;
+	    }
+	}
+    }
+    return (actions);
+}
+
+action *
+add_reductions(stateno, actions)
+int stateno;
+register action *actions;
+{
+    register int i, j, m, n;
+    register int ruleno, tokensetsize;
+    register unsigned *rowp;
+
+    tokensetsize = WORDSIZE(ntokens);
+    m = lookaheads[stateno];
+    n = lookaheads[stateno + 1];
+    for (i = m; i < n; i++)
+    {
+	ruleno = LAruleno[i];
+	rowp = LA + i * tokensetsize;
+	for (j = ntokens - 1; j >= 0; j--)
+	{
+	    if (BIT(rowp, j))
+		actions = add_reduce(actions, ruleno, j);
+	}
+    }
+    return (actions);
+}
+
+
+action *
+add_reduce(actions, ruleno, symbol)
+register action *actions;
+register int ruleno, symbol;
+{
+    register action *temp, *prev, *next;
+
+    prev = 0;
+    for (next = actions; next && next->symbol < symbol; next = next->next)
+	prev = next;
+
+    while (next && next->symbol == symbol && next->action_code == SHIFT)
+    {
+	prev = next;
+	next = next->next;
+    }
+
+    while (next && next->symbol == symbol &&
+	    next->action_code == REDUCE && next->number < ruleno)
+    {
+	prev = next;
+	next = next->next;
+    }
+
+    temp = NEW(action);
+    temp->next = next;
+    temp->symbol = symbol;
+    temp->number = ruleno;
+    temp->prec = rprec[ruleno];
+    temp->action_code = REDUCE;
+    temp->assoc = rassoc[ruleno];
+
+    if (prev)
+	prev->next = temp;
+    else
+	actions = temp;
+
+    return (actions);
+}
+
+
+find_final_state()
+{
+    register int goal, i;
+    register short *to_state;
+    register shifts *p;
+
+    p = shift_table[0];
+    to_state = p->shift;
+    goal = ritem[1];
+    for (i = p->nshifts - 1; i >= 0; --i)
+    {
+	final_state = to_state[i];
+	if (accessing_symbol[final_state] == goal) break;
+    }
+}
+
+
+unused_rules()
+{
+    register int i;
+    register action *p;
+
+    rules_used = (short *) MALLOC(nrules*sizeof(short));
+    if (rules_used == 0) no_space();
+
+    for (i = 0; i < nrules; ++i)
+	rules_used[i] = 0;
+
+    for (i = 0; i < nstates; ++i)
+    {
+	for (p = parser[i]; p; p = p->next)
+	{
+	    if (p->action_code == REDUCE && p->suppressed == 0)
+		rules_used[p->number] = 1;
+	}
+    }
+
+    nunused = 0;
+    for (i = 3; i < nrules; ++i)
+	if (!rules_used[i]) ++nunused;
+
+    if (nunused)
+	if (nunused == 1)
+	    fprintf(stderr, "%s: 1 rule never reduced\n", myname);
+	else
+	    fprintf(stderr, "%s: %d rules never reduced\n", myname, nunused);
+}
+
+
+remove_conflicts()
+{
+    register int i;
+    register int symbol;
+    register action *p, *q;
+
+    SRtotal = 0;
+    RRtotal = 0;
+    SRconflicts = NEW2(nstates, short);
+    RRconflicts = NEW2(nstates, short);
+    for (i = 0; i < nstates; i++)
+    {
+	SRcount = 0;
+	RRcount = 0;
+	for (p = parser[i]; p; p = q->next)
+	{
+	    symbol = p->symbol;
+	    q = p;
+	    while (q->next && q->next->symbol == symbol)
+		q = q->next;
+	    if (i == final_state && symbol == 0)
+		end_conflicts(p, q);
+	    else if (p != q)
+		resolve_conflicts(p, q);
+	}
+	SRtotal += SRcount;
+	RRtotal += RRcount;
+	SRconflicts[i] = SRcount;
+	RRconflicts[i] = RRcount;
+    }
+}
+
+
+end_conflicts(p, q)
+register action *p, *q;
+{
+    for (;;)
+    {
+	SRcount++;
+	p->suppressed = 1;
+	if (p == q) break;
+	p = p->next;
+    }
+}
+
+
+resolve_conflicts(first, last)
+register action *first, *last;
+{
+    register action *p;
+    register int count;
+
+    count = 1;
+    for (p = first; p != last; p = p->next)
+ 	++count;
+    assert(count > 1);
+
+    if (first->action_code == SHIFT && count == 2 &&
+	    first->prec > 0 && last->prec > 0)
+    {
+	if (first->prec == last->prec)
+	{
+	    if (first->assoc == LEFT)
+		first->suppressed = 2;
+	    else if (first->assoc == RIGHT)
+		last->suppressed = 2;
+	    else
+	    {
+		first->suppressed = 2;
+		last->suppressed = 2;
+		first->action_code = ERROR;
+		last->action_code = ERROR;
+	    }
+	}
+	else if (first->prec < last->prec)
+	    first->suppressed = 2;
+	else
+	    last->suppressed = 2;
+    }
+    else
+    {
+	if (first->action_code == SHIFT)
+	    SRcount += (count - 1);
+        else
+	    RRcount += (count - 1);
+	for (p = first; p != last; p = p->next, p->suppressed = 1)
+	    continue;
+    }
+}
+
+
+total_conflicts()
+{
+    fprintf(stderr, "%s: ", myname);
+    if (SRtotal == 1)
+	fprintf(stderr, "1 shift/reduce conflict");
+    else if (SRtotal > 1)
+	fprintf(stderr, "%d shift/reduce conflicts", SRtotal);
+
+    if (SRtotal && RRtotal)
+	fprintf(stderr, ", ");
+
+    if (RRtotal == 1)
+	fprintf(stderr, "1 reduce/reduce conflict");
+    else if (RRtotal > 1)
+	fprintf(stderr, "%d reduce/reduce conflicts", RRtotal);
+
+    fprintf(stderr, ".\n");
+}
+
+
+int
+sole_reduction(stateno)
+int stateno;
+{
+    register int count, ruleno;
+    register action *p;
+
+    count = 0;
+    ruleno = 0; 
+    for (p = parser[stateno]; p; p = p->next)
+    {
+	if (p->action_code == SHIFT && p->suppressed == 0)
+	    return (0);
+	else if (p->action_code == REDUCE && p->suppressed == 0)
+	{
+	    if (ruleno > 0 && p->number != ruleno)
+		return (0);
+	    if (p->symbol != 1)
+		++count;
+	    ruleno = p->number;
+	}
+    }
+
+    if (count == 0)
+	return (0);
+    return (ruleno);
+}
+
+
+defreds()
+{
+    register int i;
+
+    defred = NEW2(nstates, short);
+    for (i = 0; i < nstates; i++)
+	defred[i] = sole_reduction(i);
+}
+ 
+free_action_row(p)
+register action *p;
+{
+  register action *q;
+
+  while (p)
+    {
+      q = p->next;
+      FREE(p);
+      p = q;
+    }
+}
+
+free_parser()
+{
+  register int i;
+
+  for (i = 0; i < nstates; i++)
+    free_action_row(parser[i]);
+
+  FREE(parser);
+}