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style: scope reduction in lalr.c

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* src/lalr.c: here.
This commit is contained in:
Akim Demaille
2018-12-05 06:46:07 +01:00
parent cfd682f46d
commit 4176584062
1 changed files with 56 additions and 82 deletions
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138
src/lalr.c
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@@ -40,10 +40,10 @@
#include "relation.h"
#include "symtab.h"
goto_number *goto_map;
goto_number ngotos;
state_number *from_state;
state_number *to_state;
goto_number *goto_map = NULL;
goto_number ngotos = 0;
state_number *from_state = NULL;
state_number *to_state = NULL;
bitsetv goto_follows = NULL;
/* Linked list of goto numbers. */
@@ -70,16 +70,14 @@ static goto_list **lookback;
void
set_goto_map (void)
{
state_number s;
goto_number *temp_map = xnmalloc (nvars + 1, sizeof *temp_map);
goto_map = xcalloc (nvars + 1, sizeof *goto_map);
ngotos = 0;
for (s = 0; s < nstates; ++s)
for (state_number s = 0; s < nstates; ++s)
{
transitions *sp = states[s]->transitions;
int i;
for (i = sp->num - 1; i >= 0 && TRANSITION_IS_GOTO (sp, i); --i)
for (int i = sp->num - 1; i >= 0 && TRANSITION_IS_GOTO (sp, i); --i)
{
ngotos++;
@@ -92,14 +90,13 @@ set_goto_map (void)
{
goto_number k = 0;
int i;
for (i = ntokens; i < nsyms; i++)
for (symbol_number i = ntokens; i < nsyms; ++i)
{
temp_map[i - ntokens] = k;
k += goto_map[i - ntokens];
}
for (i = ntokens; i < nsyms; i++)
for (symbol_number i = ntokens; i < nsyms; ++i)
goto_map[i - ntokens] = temp_map[i - ntokens];
goto_map[nsyms - ntokens] = ngotos;
@@ -109,11 +106,10 @@ set_goto_map (void)
from_state = xcalloc (ngotos, sizeof *from_state);
to_state = xcalloc (ngotos, sizeof *to_state);
for (s = 0; s < nstates; ++s)
for (state_number s = 0; s < nstates; ++s)
{
transitions *sp = states[s]->transitions;
int i;
for (i = sp->num - 1; i >= 0 && TRANSITION_IS_GOTO (sp, i); --i)
const transitions *sp = states[s]->transitions;
for (int i = sp->num - 1; i >= 0 && TRANSITION_IS_GOTO (sp, i); --i)
{
goto_number k = temp_map[TRANSITION_SYMBOL (sp, i) - ntokens]++;
from_state[k] = s;
@@ -133,11 +129,9 @@ map_goto (state_number s0, symbol_number sym)
for (;;)
{
goto_number middle;
state_number s;
aver (low <= high);
middle = (low + high) / 2;
s = from_state[middle];
goto_number middle = (low + high) / 2;
state_number s = from_state[middle];
if (s == s0)
return middle;
else if (s < s0)
@@ -155,20 +149,18 @@ initialize_F (void)
goto_number *edge = xnmalloc (ngotos + 1, sizeof *edge);
goto_number nedges = 0;
goto_number i;
goto_follows = bitsetv_create (ngotos, ntokens, BITSET_FIXED);
for (i = 0; i < ngotos; i++)
for (goto_number i = 0; i < ngotos; ++i)
{
state_number stateno = to_state[i];
transitions *sp = states[stateno]->transitions;
const transitions *sp = states[stateno]->transitions;
int j;
FOR_EACH_SHIFT (sp, j)
bitset_set (goto_follows[i], TRANSITION_SYMBOL (sp, j));
for (; j < sp->num; j++)
for (; j < sp->num; ++j)
{
symbol_number sym = TRANSITION_SYMBOL (sp, j);
if (nullable[sym - ntokens])
@@ -188,7 +180,7 @@ initialize_F (void)
relation_digraph (reads, ngotos, &goto_follows);
for (i = 0; i < ngotos; i++)
for (goto_number i = 0; i < ngotos; ++i)
free (reads[i]);
free (reads);
@@ -213,19 +205,16 @@ build_relations (void)
{
goto_number *edge = xnmalloc (ngotos + 1, sizeof *edge);
state_number *states1 = xnmalloc (ritem_longest_rhs () + 1, sizeof *states1);
goto_number i;
includes = xnmalloc (ngotos, sizeof *includes);
for (i = 0; i < ngotos; i++)
for (goto_number i = 0; i < ngotos; ++i)
{
int nedges = 0;
symbol_number symbol1 = states[to_state[i]]->accessing_symbol;
rule **rulep;
for (rulep = derives[symbol1 - ntokens]; *rulep; rulep++)
for (rule **rulep = derives[symbol1 - ntokens]; *rulep; rulep++)
{
bool done;
int length = 1;
item_number const *rp;
state *s = states[from_state[i]];
@@ -242,7 +231,7 @@ build_relations (void)
add_lookback_edge (s, *rulep, i);
length--;
done = false;
bool done = false;
while (!done)
{
done = true;
@@ -265,9 +254,8 @@ build_relations (void)
includes[i] = NULL;
else
{
int j;
includes[i] = xnmalloc (nedges + 1, sizeof includes[i][0]);
for (j = 0; j < nedges; j++)
for (int j = 0; j < nedges; ++j)
includes[i][j] = edge[j];
includes[i][nedges] = END_NODE;
}
@@ -284,11 +272,9 @@ build_relations (void)
static void
compute_FOLLOWS (void)
{
goto_number i;
relation_digraph (includes, ngotos, &goto_follows);
for (i = 0; i < ngotos; i++)
for (goto_number i = 0; i < ngotos; ++i)
free (includes[i]);
free (includes);
@@ -298,15 +284,12 @@ compute_FOLLOWS (void)
static void
compute_lookahead_tokens (void)
{
size_t i;
goto_list *sp;
for (i = 0; i < nLA; i++)
for (sp = lookback[i]; sp; sp = sp->next)
for (size_t i = 0; i < nLA; ++i)
for (goto_list *sp = lookback[i]; sp; sp = sp->next)
bitset_or (LA[i], LA[i], goto_follows[sp->value]);
/* Free LOOKBACK. */
for (i = 0; i < nLA; i++)
for (size_t i = 0; i < nLA; ++i)
LIST_FREE (goto_list, lookback[i]);
free (lookback);
@@ -359,8 +342,6 @@ state_lookahead_tokens_count (state *s, bool default_reduction_only_for_accept)
void
initialize_LA (void)
{
state_number i;
bitsetv pLA;
bool default_reduction_only_for_accept;
{
char *default_reductions =
@@ -371,7 +352,7 @@ initialize_LA (void)
/* Compute the total number of reductions requiring a lookahead. */
nLA = 0;
for (i = 0; i < nstates; i++)
for (state_number i = 0; i < nstates; ++i)
nLA +=
state_lookahead_tokens_count (states[i],
default_reduction_only_for_accept);
@@ -379,11 +360,11 @@ initialize_LA (void)
if (!nLA)
nLA = 1;
pLA = LA = bitsetv_create (nLA, ntokens, BITSET_FIXED);
bitsetv pLA = LA = bitsetv_create (nLA, ntokens, BITSET_FIXED);
/* Initialize the members LOOKAHEAD_TOKENS for each state whose reductions
require lookahead tokens. */
for (i = 0; i < nstates; i++)
for (state_number i = 0; i < nstates; ++i)
{
int count =
state_lookahead_tokens_count (states[i],
@@ -404,34 +385,30 @@ initialize_LA (void)
static void
lookahead_tokens_print (FILE *out)
{
state_number i;
fprintf (out, "Lookahead tokens: BEGIN\n");
for (i = 0; i < nstates; ++i)
for (state_number i = 0; i < nstates; ++i)
{
reductions *reds = states[i]->reductions;
bitset_iterator iter;
const reductions *reds = states[i]->reductions;
int n_lookahead_tokens = 0;
if (reds->lookahead_tokens)
{
int j;
for (j = 0; j < reds->num; ++j)
if (reds->lookahead_tokens[j])
++n_lookahead_tokens;
}
for (int j = 0; j < reds->num; ++j)
if (reds->lookahead_tokens[j])
++n_lookahead_tokens;
fprintf (out, "State %d: %d lookahead tokens\n",
i, n_lookahead_tokens);
if (reds->lookahead_tokens)
{
int j, k;
for (j = 0; j < reds->num; ++j)
for (int j = 0; j < reds->num; ++j)
{
bitset_iterator iter;
int k;
BITSET_FOR_EACH (iter, reds->lookahead_tokens[j], k, 0)
fprintf (out, " on %d (%s) -> rule %d\n",
k, symbols[k]->tag,
reds->rules[j]->number);
}
}
}
fprintf (out, "Lookahead tokens: END\n");
}
@@ -458,25 +435,23 @@ lalr_update_state_numbers (state_number old_to_new[], state_number nstates_old)
goto_number ngotos_reachable = 0;
symbol_number nonterminal = 0;
aver (nsyms == nvars + ntokens);
{
goto_number i;
for (i = 0; i < ngotos; ++i)
{
while (i == goto_map[nonterminal])
goto_map[nonterminal++] = ngotos_reachable;
/* If old_to_new[from_state[i]] = nstates_old, remove this goto
entry. */
if (old_to_new[from_state[i]] != nstates_old)
{
/* from_state[i] is not removed, so it and thus to_state[i] are
reachable, so to_state[i] != nstates_old. */
aver (old_to_new[to_state[i]] != nstates_old);
from_state[ngotos_reachable] = old_to_new[from_state[i]];
to_state[ngotos_reachable] = old_to_new[to_state[i]];
++ngotos_reachable;
}
}
}
for (goto_number i = 0; i < ngotos; ++i)
{
while (i == goto_map[nonterminal])
goto_map[nonterminal++] = ngotos_reachable;
/* If old_to_new[from_state[i]] = nstates_old, remove this goto
entry. */
if (old_to_new[from_state[i]] != nstates_old)
{
/* from_state[i] is not removed, so it and thus to_state[i] are
reachable, so to_state[i] != nstates_old. */
aver (old_to_new[to_state[i]] != nstates_old);
from_state[ngotos_reachable] = old_to_new[from_state[i]];
to_state[ngotos_reachable] = old_to_new[to_state[i]];
++ngotos_reachable;
}
}
while (nonterminal <= nvars)
{
aver (ngotos == goto_map[nonterminal]);
@@ -489,8 +464,7 @@ lalr_update_state_numbers (state_number old_to_new[], state_number nstates_old)
void
lalr_free (void)
{
state_number s;
for (s = 0; s < nstates; ++s)
for (state_number s = 0; s < nstates; ++s)
states[s]->reductions->lookahead_tokens = NULL;
bitsetv_free (LA);
}