diff options
author | Akim Demaille <akim.demaille@gmail.com> | 2021-01-24 09:22:49 +0100 |
---|---|---|
committer | Akim Demaille <akim.demaille@gmail.com> | 2021-01-24 09:22:49 +0100 |
commit | c94456986d590cc58cb7f7fd151c132c13a49644 (patch) | |
tree | 85caa9ec9558879206d8d940209c9155b4b3be98 /src | |
parent | fb144c021c535c687b023601c7d3f40820074dfb (diff) | |
parent | 2fac23b9ddf13bfc7ad8326ec112a4d138774565 (diff) | |
download | bison-c94456986d590cc58cb7f7fd151c132c13a49644.tar.gz |
Merge tag 'v3.7.5'
Three new commits:
commit 8358090292e21c61a583da542bad9099ad65f355
Author: Paul Eggert <eggert@cs.ucla.edu>
Date: Wed Jan 20 18:30:16 2021 -0800
c: port to HP-UX 11.23
commit 2c294c132528ede23d8ae4959783a67e9ff05ac5
Author: Vincent Imbimbo <vmi6@cornell.edu>
Date: Sat Jan 23 13:25:18 2021 -0500
cex: fix state-item pruning
commit c22902e360e0fbbe9fd5657dcf107e03166da309
Author: Akim Demaille <akim.demaille@gmail.com>
Date: Sat Jan 23 18:40:15 2021 +0100
tables: fix handling for useless tokens
Diffstat (limited to 'src')
-rw-r--r-- | src/state-item.c | 59 | ||||
-rw-r--r-- | src/tables.c | 83 |
2 files changed, 95 insertions, 47 deletions
diff --git a/src/state-item.c b/src/state-item.c index 2fa519ed..fea56a59 100644 --- a/src/state-item.c +++ b/src/state-item.c @@ -384,11 +384,10 @@ disable_state_item (state_item *si) bitset_free (si->prods); } -/* disable all transitions and productions that can only be - * reached through this state_item. - */ +/* Disable all state_item paths that lead to/from SI and nowhere + else. */ static void -prune_forward (const state_item *si) +prune_state_item (const state_item *si) { state_item_list queue = gl_list_create (GL_LINKED_LIST, NULL, NULL, NULL, true, 1, @@ -398,8 +397,16 @@ prune_forward (const state_item *si) { state_item *dsi = (state_item *) gl_list_get_at (queue, 0); gl_list_remove_at (queue, 0); - if (dsi->trans >= 0) - gl_list_add_last (queue, &state_items[dsi->trans]); + if (SI_DISABLED (dsi - state_items)) + continue; + + if (dsi->trans >= 0 && !SI_DISABLED (dsi->trans)) + { + const state_item *trans = &state_items[dsi->trans]; + bitset_reset (trans->revs, dsi - state_items); + if (bitset_empty_p (trans->revs)) + gl_list_add_last (queue, trans); + } if (dsi->prods) { @@ -407,32 +414,15 @@ prune_forward (const state_item *si) state_item_number sin; BITSET_FOR_EACH (biter, dsi->prods, sin, 0) { + if (SI_DISABLED (sin)) + continue; const state_item *prod = &state_items[sin]; bitset_reset (prod->revs, dsi - state_items); if (bitset_empty_p (prod->revs)) gl_list_add_last (queue, prod); } } - if (dsi != si) - disable_state_item (dsi); - } - gl_list_free (queue); -} -/* disable all state_item paths that lead to - * si and nowhere else. - */ -static void -prune_backward (const state_item *si) -{ - state_item_list queue = - gl_list_create (GL_LINKED_LIST, NULL, NULL, NULL, true, 1, - (const void **) &si); - - while (gl_list_size (queue) > 0) - { - state_item *dsi = (state_item *) gl_list_get_at (queue, 0); - gl_list_remove_at (queue, 0); bitset_iterator biter; state_item_number sin; BITSET_FOR_EACH (biter, dsi->revs, sin, 0) @@ -440,7 +430,9 @@ prune_backward (const state_item *si) if (SI_DISABLED (sin)) continue; state_item *rev = &state_items[sin]; - if (rev->prods) + if (&state_items[rev->trans] == dsi) + gl_list_add_last (queue, rev); + else if (rev->prods) { bitset_reset (rev->prods, dsi - state_items); if (bitset_empty_p (rev->prods)) @@ -449,16 +441,13 @@ prune_backward (const state_item *si) else gl_list_add_last (queue, rev); } - if (dsi != si) - disable_state_item (dsi); + disable_state_item (dsi); } gl_list_free (queue); } -/* - To make searches more efficient, we can prune away paths that are - caused by disabled transitions. - */ +/* To make searches more efficient, prune away paths that are caused + by disabled transitions. */ static void prune_disabled_paths (void) { @@ -466,11 +455,7 @@ prune_disabled_paths (void) { state_item *si = &state_items[i]; if (si->trans == -1 && item_number_is_symbol_number (*si->item)) - { - prune_forward (si); - prune_backward (si); - disable_state_item (si); - } + prune_state_item (si); } } diff --git a/src/tables.c b/src/tables.c index 0c98c327..b04a496e 100644 --- a/src/tables.c +++ b/src/tables.c @@ -111,9 +111,13 @@ base_number *base = NULL; computation equals to BASE_MINIMUM, later mapped to BASE_NINF to keep parser tables small. */ base_number base_ninf = 0; + /* Bitset representing an integer set in the range - -nstates..table_size (as an upper bound) */ + POS_SET_OFFSET..(POS_SET_OFFSET + SIZE). POS_SET_OFFSET is + nonpositive. */ static bitset pos_set = NULL; +/* The integer denoted by bitno 0 in pos_set. */ +static int pos_set_base = 0; static int *conflrow; int *conflict_table; @@ -138,6 +142,71 @@ int high; state_number *yydefgoto; rule_number *yydefact; + +/*----------. +| pos_set. | +`----------*/ + +#if 0 +static void +pos_set_dump (void) +{ + fprintf (stderr, "pos_set (%ld, %d) =", bitset_size (pos_set), pos_set_base); + bitset_iterator biter; + int i; + BITSET_FOR_EACH (biter, pos_set, i, 0) + fprintf (stderr, " %d", i + pos_set_base); + putc ('\n', stderr); +} +#endif + + +/* The size and base of POS_SET are not known, we need to be able to + move the base farther "on the left", and grow "on the right". + + It would be nice to be able to predict the base accurately, but it + seems difficult (-nstates seems to work most of the time, except + when there are useless tokens). + + FIXME: The current approach is correct, but with poor performances. + Bitsets need to support 'assign' and 'shift'. And instead of + extending POS_SET just for the out-of-range new values, we need + something like doubling the size. + */ + +static void +pos_set_set (int pos) +{ + int bitno = pos - pos_set_base; + if (bitno < 0) + { + const int delta = pos_set_base - pos; + const int old_size = bitset_size (pos_set); + const int new_size = old_size + delta; + bitset_resize (pos_set, new_size); + // Shift all the bits by DELTA. + // FIXME: add bitset_assign, and bitset_shift? + for (int i = new_size - 1; delta <= i ; --i) + if (bitset_test (pos_set, i)) + bitset_set (pos_set, i + delta); + else + bitset_reset (pos_set, i + delta); + pos_set_base = pos; + bitno = 0; + } + else if (bitset_size (pos_set) <= bitno) + bitset_resize (pos_set, bitno + 1); + bitset_set (pos_set, bitno); +} + +static bool +pos_set_test (int pos) +{ + const int bitno = pos - pos_set_base; + return bitset_test (pos_set, bitno); +} + + /*-------------------------------------------------------------------. | If TABLE, CONFLICT_TABLE, and CHECK are too small to be addressed | | at DESIRED, grow them. TABLE[DESIRED] can be used, so the desired | @@ -168,8 +237,6 @@ table_grow (int desired) check = xnrealloc (check, table_size, sizeof *check); for (int i = old_size; i < table_size; ++i) check[i] = -1; - - bitset_resize (pos_set, table_size + nstates); } @@ -672,7 +739,7 @@ pack_vector (vector_number vector) ok = false; } - if (ok && bitset_test (pos_set, nstates + res)) + if (ok && pos_set_test (res)) ok = false; } @@ -732,6 +799,7 @@ pack_table (void) { base = xnmalloc (nvectors, sizeof *base); pos_set = bitset_create (table_size + nstates, BITSET_FRUGAL); + pos_set_base = -nstates; table = xcalloc (table_size, sizeof *table); conflict_table = xcalloc (table_size, sizeof *conflict_table); check = xnmalloc (table_size, sizeof *check); @@ -757,12 +825,7 @@ pack_table (void) /* Action of I were already coded for S. */ place = base[s]; - /* Store PLACE into POS_SET. PLACE might not belong to the set - of possible values for instance with useless tokens. It - would be more satisfying to eliminate the need for this - 'if'. */ - if (0 <= nstates + place) - bitset_set (pos_set, nstates + place); + pos_set_set (place); base[order[i]] = place; } |