Future/bison
1
0
Fork 0
mirror of https://git.savannah.gnu.org/git/bison.git synced 2026-03-09 20:33:03 +00:00
Code Issues Packages Projects Releases Wiki Activity

If conflict resolution makes states unreachable, remove those states,

Browse Source 
report rules that are then unused, and don't report conflicts in those
states.
* src/conflicts.c, src/conflicts.h (conflicts_update_state_numbers):
New global function.
* src/lalr.c, src/lalr.h (lalr_update_state_numbers): New global
function.
* src/main.c (main): After conflict resolution, remove the unreachable
states and update all data structures that reference states by number.
* src/state.c (state_new): Initialize each state's reachable member to
false.
(state_mark_reachable_states): New static function.
(state_remove_unreachable_states): New global function.
* src/state.h (struct state): Add member bool reachable.
(state_remove_unreachable_states): Prototype.
* tests/conflicts.at (Unreachable States After Conflict Resolution):
New test case.
* tests/existing.at (GNU pic Grammar): Update test case output now that
an unused rule is discovered.
This commit is contained in:
Joel E. Denny
2007-05-07 02:56:56 +00:00
parent b09f4f4851
commit 5967f0cf59
10 changed files with 347 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

39
src/state.c
View File

@@ -145,6 +145,7 @@ state_new (symbol_number accessing_symbol,
res->errs = NULL;
res->consistent = 0;
res->solved_conflicts = NULL;
res->reachable = false;
res->nitems = nitems;
memcpy (res->items, core, items_size);
@@ -352,6 +353,44 @@ state_hash_lookup (size_t nitems, item_number *core)
return entry;
}
/*------------------------------------------------------.
| Mark S and all states reachable from S as reachable. |
`------------------------------------------------------*/
static void
state_mark_reachable_states (state *s)
{
if (s->reachable)
return;
s->reachable = true;
for (int i = 0; i < s->transitions->num; ++i)
if (!TRANSITION_IS_DISABLED (s->transitions, i))
state_mark_reachable_states (s->transitions->states[i]);
}
void
state_remove_unreachable_states (state_number old_to_new[])
{
state_number nstates_reachable = 0;
state_mark_reachable_states (states[0]);
for (state_number i = 0; i < nstates; ++i)
{
if (states[i]->reachable)
{
states[nstates_reachable] = states[i];
states[nstates_reachable]->number = nstates_reachable;
old_to_new[i] = nstates_reachable++;
}
else
{
state_free (states[i]);
old_to_new[i] = nstates;
}
}
nstates = nstates_reachable;
}
/* All the decorated states, indexed by the state number. */
state **states = NULL;