diff options
Diffstat (limited to 'gcc/except.c')
| -rw-r--r-- | gcc/except.c | 248 |
1 files changed, 199 insertions, 49 deletions
diff --git a/gcc/except.c b/gcc/except.c index e5079f99e0d..d4a903e597c 100644 --- a/gcc/except.c +++ b/gcc/except.c @@ -98,8 +98,15 @@ int (*lang_eh_type_covers) PARAMS ((tree a, tree b)); /* Map a type to a runtime object to match type. */ tree (*lang_eh_runtime_type) PARAMS ((tree)); -/* A list of labels used for exception handlers. */ -rtx exception_handler_labels; +/* A hash table of label to region number. */ + +struct ehl_map_entry +{ + rtx label; + struct eh_region *region; +}; + +static htab_t exception_handler_label_map; static int call_site_base; static unsigned int sjlj_funcdef_number; @@ -126,6 +133,10 @@ struct eh_region /* An identifier for this region. */ int region_number; + /* When a region is deleted, its parents inherit the REG_EH_REGION + numbers already assigned. */ + bitmap aka; + /* Each region does exactly one thing. */ enum eh_region_type { @@ -242,6 +253,10 @@ struct eh_status static void mark_eh_region PARAMS ((struct eh_region *)); +static int mark_ehl_map_entry PARAMS ((PTR *, PTR)); +static void mark_ehl_map PARAMS ((void *)); + +static void free_region PARAMS ((struct eh_region *)); static int t2r_eq PARAMS ((const PTR, const PTR)); @@ -292,8 +307,15 @@ static void sjlj_emit_dispatch_table PARAMS ((rtx, struct sjlj_lp_info *)); static void sjlj_build_landing_pads PARAMS ((void)); +static hashval_t ehl_hash PARAMS ((const PTR)); +static int ehl_eq PARAMS ((const PTR, + const PTR)); +static void ehl_free PARAMS ((PTR)); +static void add_ehl_entry PARAMS ((rtx, + struct eh_region *)); static void remove_exception_handler_label PARAMS ((rtx)); static void remove_eh_handler PARAMS ((struct eh_region *)); +static int for_each_eh_label_1 PARAMS ((PTR *, PTR)); struct reachable_info; @@ -364,7 +386,7 @@ doing_eh (do_warn) void init_eh () { - ggc_add_rtx_root (&exception_handler_labels, 1); + ggc_add_root (&exception_handler_label_map, 1, 1, mark_ehl_map); if (! flag_exceptions) return; @@ -511,6 +533,25 @@ mark_eh_region (region) ggc_mark_rtx (region->post_landing_pad); } +static int +mark_ehl_map_entry (pentry, data) + PTR *pentry; + PTR data ATTRIBUTE_UNUSED; +{ + struct ehl_map_entry *entry = *(struct ehl_map_entry **) pentry; + ggc_mark_rtx (entry->label); + return 1; +} + +static void +mark_ehl_map (pp) + void *pp; +{ + htab_t map = *(htab_t *) pp; + if (map) + htab_traverse (map, mark_ehl_map_entry, NULL); +} + void mark_eh_status (eh) struct eh_status *eh; @@ -572,6 +613,16 @@ mark_eh_status (eh) ggc_mark_rtx (eh->sjlj_exit_after); } +static inline void +free_region (r) + struct eh_region *r; +{ + /* Note that the aka bitmap is freed by regset_release_memory. But if + we ever replace with a non-obstack implementation, this would be + the place to do it. */ + free (r); +} + void free_eh_status (f) struct function *f; @@ -586,7 +637,7 @@ free_eh_status (f) struct eh_region *r = eh->region_array[i]; /* Mind we don't free a region struct more than once. */ if (r && r->region_number == i) - free (r); + free_region (r); } free (eh->region_array); } @@ -600,20 +651,20 @@ free_eh_status (f) else if (r->next_peer) { next = r->next_peer; - free (r); + free_region (r); r = next; } else { do { next = r->outer; - free (r); + free_region (r); r = next; if (r == NULL) goto tree_done; } while (r->next_peer == NULL); next = r->next_peer; - free (r); + free_region (r); r = next; } } @@ -628,7 +679,12 @@ free_eh_status (f) free (eh); f->eh = NULL; - exception_handler_labels = NULL; + + if (exception_handler_label_map) + { + htab_delete (exception_handler_label_map); + exception_handler_label_map = NULL; + } } @@ -1312,13 +1368,50 @@ convert_from_eh_region_ranges () remove_unreachable_regions (insns); } +static void +add_ehl_entry (label, region) + rtx label; + struct eh_region *region; +{ + struct ehl_map_entry **slot, *entry; + + LABEL_PRESERVE_P (label) = 1; + + entry = (struct ehl_map_entry *) xmalloc (sizeof (*entry)); + entry->label = label; + entry->region = region; + + slot = (struct ehl_map_entry **) + htab_find_slot (exception_handler_label_map, entry, INSERT); + if (*slot) + abort (); + *slot = entry; +} + +static void +ehl_free (pentry) + PTR pentry; +{ + struct ehl_map_entry *entry = (struct ehl_map_entry *)pentry; + LABEL_PRESERVE_P (entry->label) = 0; + free (entry); +} + void find_exception_handler_labels () { - rtx list = NULL_RTX; int i; - free_EXPR_LIST_list (&exception_handler_labels); + if (exception_handler_label_map) + htab_empty (exception_handler_label_map); + else + { + /* ??? The expansion factor here (3/2) must be greater than the htab + occupancy factor (4/3) to avoid unnecessary resizing. */ + exception_handler_label_map + = htab_create (cfun->eh->last_region_number * 3 / 2, + ehl_hash, ehl_eq, ehl_free); + } if (cfun->eh->region_tree == NULL) return; @@ -1336,15 +1429,13 @@ find_exception_handler_labels () lab = region->label; if (lab) - list = alloc_EXPR_LIST (0, lab, list); + add_ehl_entry (lab, region); } /* For sjlj exceptions, need the return label to remain live until after landing pad generation. */ if (USING_SJLJ_EXCEPTIONS && ! cfun->eh->built_landing_pads) - list = alloc_EXPR_LIST (0, return_label, list); - - exception_handler_labels = list; + add_ehl_entry (return_label, NULL); } bool @@ -2430,28 +2521,50 @@ finish_eh_generation () cleanup_cfg (CLEANUP_PRE_LOOP); } +static hashval_t +ehl_hash (pentry) + const PTR pentry; +{ + struct ehl_map_entry *entry = (struct ehl_map_entry *) pentry; + + /* 2^32 * ((sqrt(5) - 1) / 2) */ + const hashval_t scaled_golden_ratio = 0x9e3779b9; + return CODE_LABEL_NUMBER (entry->label) * scaled_golden_ratio; +} + +static int +ehl_eq (pentry, pdata) + const PTR pentry; + const PTR pdata; +{ + struct ehl_map_entry *entry = (struct ehl_map_entry *) pentry; + struct ehl_map_entry *data = (struct ehl_map_entry *) pdata; + + return entry->label == data->label; +} + /* This section handles removing dead code for flow. */ -/* Remove LABEL from the exception_handler_labels list. */ +/* Remove LABEL from exception_handler_label_map. */ static void remove_exception_handler_label (label) rtx label; { - rtx *pl, l; + struct ehl_map_entry **slot, tmp; - /* If exception_handler_labels was not built yet, + /* If exception_handler_label_map was not built yet, there is nothing to do. */ - if (exception_handler_labels == NULL) + if (exception_handler_label_map == NULL) return; - for (pl = &exception_handler_labels, l = *pl; - XEXP (l, 0) != label; - pl = &XEXP (l, 1), l = *pl) - continue; + tmp.label = label; + slot = (struct ehl_map_entry **) + htab_find_slot (exception_handler_label_map, &tmp, NO_INSERT); + if (! slot) + abort (); - *pl = XEXP (l, 1); - free_EXPR_LIST_node (l); + htab_clear_slot (exception_handler_label_map, (void **) slot); } /* Splice REGION from the region tree etc. */ @@ -2462,16 +2575,29 @@ remove_eh_handler (region) { struct eh_region **pp, *p; rtx lab; - int i; /* For the benefit of efficiently handling REG_EH_REGION notes, replace this region in the region array with its containing region. Note that previous region deletions may result in - multiple copies of this region in the array, so we have to - search the whole thing. */ - for (i = cfun->eh->last_region_number; i > 0; --i) - if (cfun->eh->region_array[i] == region) - cfun->eh->region_array[i] = region->outer; + multiple copies of this region in the array, so we have a + list of alternate numbers by which we are known. */ + + cfun->eh->region_array[region->region_number] = region->outer; + if (region->aka) + { + int i; + EXECUTE_IF_SET_IN_BITMAP (region->aka, 0, i, + { cfun->eh->region_array[i] = region->outer; }); + } + + if (region->outer) + { + if (!region->outer->aka) + region->outer->aka = BITMAP_XMALLOC (); + if (region->aka) + bitmap_a_or_b (region->outer->aka, region->outer->aka, region->aka); + bitmap_set_bit (region->outer->aka, region->region_number); + } if (cfun->eh->built_landing_pads) lab = region->landing_pad; @@ -2526,7 +2652,7 @@ remove_eh_handler (region) } } - free (region); + free_region (region); } /* LABEL heads a basic block that is about to be deleted. If this @@ -2537,7 +2663,8 @@ void maybe_remove_eh_handler (label) rtx label; { - int i; + struct ehl_map_entry **slot, tmp; + struct eh_region *region; /* ??? After generating landing pads, it's not so simple to determine if the region data is completely unused. One must examine the @@ -2546,27 +2673,50 @@ maybe_remove_eh_handler (label) if (cfun->eh->built_landing_pads) return; - for (i = cfun->eh->last_region_number; i > 0; --i) + tmp.label = label; + slot = (struct ehl_map_entry **) + htab_find_slot (exception_handler_label_map, &tmp, NO_INSERT); + if (! slot) + return; + region = (*slot)->region; + if (! region) + return; + + /* Flow will want to remove MUST_NOT_THROW regions as unreachable + because there is no path to the fallback call to terminate. + But the region continues to affect call-site data until there + are no more contained calls, which we don't see here. */ + if (region->type == ERT_MUST_NOT_THROW) { - struct eh_region *region = cfun->eh->region_array[i]; - if (region && region->label == label) - { - /* Flow will want to remove MUST_NOT_THROW regions as unreachable - because there is no path to the fallback call to terminate. - But the region continues to affect call-site data until there - are no more contained calls, which we don't see here. */ - if (region->type == ERT_MUST_NOT_THROW) - { - remove_exception_handler_label (region->label); - region->label = NULL_RTX; - } - else - remove_eh_handler (region); - break; - } + htab_clear_slot (exception_handler_label_map, (void **) slot); + region->label = NULL_RTX; } + else + remove_eh_handler (region); +} + +/* Invokes CALLBACK for every exception handler label. Only used by old + loop hackery; should not be used by new code. */ + +void +for_each_eh_label (callback) + void (*callback) PARAMS ((rtx)); +{ + htab_traverse (exception_handler_label_map, for_each_eh_label_1, + (void *)callback); } +static int +for_each_eh_label_1 (pentry, data) + PTR *pentry; + PTR data; +{ + struct ehl_map_entry *entry = *(struct ehl_map_entry **)pentry; + void (*callback) PARAMS ((rtx)) = (void (*) PARAMS ((rtx))) data; + + (*callback) (entry->label); + return 1; +} /* This section describes CFG exception edges for flow. */ |