diff options
Diffstat (limited to 'gcc/tree-eh.c')
| -rw-r--r-- | gcc/tree-eh.c | 2611 |
1 files changed, 1628 insertions, 983 deletions
diff --git a/gcc/tree-eh.c b/gcc/tree-eh.c index ac87f424dcd..a1aa4b21571 100644 --- a/gcc/tree-eh.c +++ b/gcc/tree-eh.c @@ -38,6 +38,7 @@ along with GCC; see the file COPYING3. If not see #include "ggc.h" #include "toplev.h" #include "gimple.h" +#include "target.h" /* In some instances a tree and a gimple need to be stored in a same table, i.e. in hash tables. This is a structure to do this. */ @@ -74,7 +75,7 @@ struct_ptr_hash (const void *a) } -/* Remember and lookup EH region data for arbitrary statements. +/* Remember and lookup EH landing pad data for arbitrary statements. Really this means any statement that could_throw_p. We could stuff this information into the stmt_ann data structure, but: @@ -86,30 +87,19 @@ struct_ptr_hash (const void *a) compared to those that can. We should be saving some amount of space by only allocating memory for those that can throw. */ -static void -record_stmt_eh_region (struct eh_region_d *region, gimple t) -{ - if (!region) - return; - - add_stmt_to_eh_region (t, get_eh_region_number (region)); -} - - -/* Add statement T in function IFUN to EH region NUM. */ +/* Add statement T in function IFUN to landing pad NUM. */ void -add_stmt_to_eh_region_fn (struct function *ifun, gimple t, int num) +add_stmt_to_eh_lp_fn (struct function *ifun, gimple t, int num) { struct throw_stmt_node *n; void **slot; - gcc_assert (num >= 0); - gcc_assert (gimple_code (t) != GIMPLE_RESX); + gcc_assert (num != 0); n = GGC_NEW (struct throw_stmt_node); n->stmt = t; - n->region_nr = num; + n->lp_nr = num; if (!get_eh_throw_stmt_table (ifun)) set_eh_throw_stmt_table (ifun, htab_create_ggc (31, struct_ptr_hash, @@ -121,21 +111,39 @@ add_stmt_to_eh_region_fn (struct function *ifun, gimple t, int num) *slot = n; } - -/* Add statement T in the current function (cfun) to EH region number - NUM. */ +/* Add statement T in the current function (cfun) to EH landing pad NUM. */ void -add_stmt_to_eh_region (gimple t, int num) +add_stmt_to_eh_lp (gimple t, int num) { - add_stmt_to_eh_region_fn (cfun, t, num); + add_stmt_to_eh_lp_fn (cfun, t, num); } +/* Add statement T to the single EH landing pad in REGION. */ -/* Remove statement T in function IFUN from the EH region holding it. */ +static void +record_stmt_eh_region (eh_region region, gimple t) +{ + if (region == NULL) + return; + if (region->type == ERT_MUST_NOT_THROW) + add_stmt_to_eh_lp_fn (cfun, t, -region->index); + else + { + eh_landing_pad lp = region->landing_pads; + if (lp == NULL) + lp = gen_eh_landing_pad (region); + else + gcc_assert (lp->next_lp == NULL); + add_stmt_to_eh_lp_fn (cfun, t, lp->index); + } +} + + +/* Remove statement T in function IFUN from its EH landing pad. */ bool -remove_stmt_from_eh_region_fn (struct function *ifun, gimple t) +remove_stmt_from_eh_lp_fn (struct function *ifun, gimple t) { struct throw_stmt_node dummy; void **slot; @@ -156,75 +164,57 @@ remove_stmt_from_eh_region_fn (struct function *ifun, gimple t) } -/* Remove statement T in the current function (cfun) from the EH - region holding it. */ +/* Remove statement T in the current function (cfun) from its + EH landing pad. */ bool -remove_stmt_from_eh_region (gimple t) +remove_stmt_from_eh_lp (gimple t) { - return remove_stmt_from_eh_region_fn (cfun, t); + return remove_stmt_from_eh_lp_fn (cfun, t); } /* Determine if statement T is inside an EH region in function IFUN. - Return the EH region number if found, return -2 if IFUN does not - have an EH table and -1 if T could not be found in IFUN's EH region - table. */ + Positive numbers indicate a landing pad index; negative numbers + indicate a MUST_NOT_THROW region index; zero indicates that the + statement is not recorded in the region table. */ int -lookup_stmt_eh_region_fn (struct function *ifun, gimple t) +lookup_stmt_eh_lp_fn (struct function *ifun, gimple t) { struct throw_stmt_node *p, n; - if (!get_eh_throw_stmt_table (ifun)) - return -2; + if (ifun->eh->throw_stmt_table == NULL) + return 0; n.stmt = t; - p = (struct throw_stmt_node *) htab_find (get_eh_throw_stmt_table (ifun), &n); - return (p ? p->region_nr : -1); + p = (struct throw_stmt_node *) htab_find (ifun->eh->throw_stmt_table, &n); + return p ? p->lp_nr : 0; } - -/* Determine if statement T is inside an EH region in the current - function (cfun). Return the EH region number if found, return -2 - if cfun does not have an EH table and -1 if T could not be found in - cfun's EH region table. */ +/* Likewise, but always use the current function. */ int -lookup_stmt_eh_region (gimple t) +lookup_stmt_eh_lp (gimple t) { /* We can get called from initialized data when -fnon-call-exceptions is on; prevent crash. */ if (!cfun) - return -1; - - return lookup_stmt_eh_region_fn (cfun, t); + return 0; + return lookup_stmt_eh_lp_fn (cfun, t); } - -/* Determine if expression T is inside an EH region in the current - function (cfun). Return the EH region number if found, return -2 - if IFUN does not have an EH table and -1 if T could not be found in - IFUN's EH region table. */ +/* Likewise, but reference a tree expression instead. */ int -lookup_expr_eh_region (tree t) +lookup_expr_eh_lp (tree t) { - /* We can get called from initialized data when -fnon-call-exceptions - is on; prevent crash. */ - if (!cfun) - return -1; - - if (!get_eh_throw_stmt_table (cfun)) - return -2; - - if (t && EXPR_P (t)) + if (cfun && cfun->eh->throw_stmt_table && t && EXPR_P (t)) { tree_ann_common_t ann = tree_common_ann (t); if (ann) - return (int) ann->rn; + return ann->lp_nr; } - - return -1; + return 0; } @@ -238,7 +228,7 @@ struct finally_tree_node when deciding whether a GOTO to a certain LABEL_DECL (which is a tree) leaves the TRY block, its necessary to record a tree in this field. Thus a treemple is used. */ - treemple child; + treemple child; gimple parent; }; @@ -263,7 +253,7 @@ record_in_finally_tree (treemple child, gimple parent) static void collect_finally_tree (gimple stmt, gimple region); -/* Go through the gimple sequence. Works with collect_finally_tree to +/* Go through the gimple sequence. Works with collect_finally_tree to record all GIMPLE_LABEL and GIMPLE_TRY statements. */ static void @@ -344,6 +334,14 @@ outside_finally_tree (treemple start, gimple target) The eh region creation is straight-forward, but frobbing all the gotos and such into shape isn't. */ +/* The sequence into which we record all EH stuff. This will be + placed at the end of the function when we're all done. */ +static gimple_seq eh_seq; + +/* Record whether an EH region contains something that can throw, + indexed by EH region number. */ +static bitmap eh_region_may_contain_throw; + /* The GOTO_QUEUE is is an array of GIMPLE_GOTO and GIMPLE_RETURN statements that are seen to escape this GIMPLE_TRY_FINALLY node. The idea is to record a gimple statement for everything except for @@ -371,7 +369,12 @@ struct leh_state /* What's "current" while constructing the eh region tree. These correspond to variables of the same name in cfun->eh, which we don't have easy access to. */ - struct eh_region_d *cur_region; + eh_region cur_region; + + /* What's "current" for the purposes of __builtin_eh_pointer. For + a CATCH, this is the associated TRY. For an EH_FILTER, this is + the associated ALLOWED_EXCEPTIONS, etc. */ + eh_region ehp_region; /* Processing of TRY_FINALLY requires a bit more state. This is split out into a separate structure so that we don't have to @@ -387,6 +390,7 @@ struct leh_tf_state in the collect_finally_tree data structures. */ gimple try_finally_expr; gimple top_p; + /* While lowering a top_p usually it is expanded into multiple statements, thus we need the following field to store them. */ gimple_seq top_p_seq; @@ -395,7 +399,7 @@ struct leh_tf_state struct leh_state *outer; /* The exception region created for it. */ - struct eh_region_d *region; + eh_region region; /* The goto queue. */ struct goto_queue_node *goto_queue; @@ -413,10 +417,6 @@ struct leh_tf_state though subsequent transformations may have cleared that flag. */ tree fallthru_label; - /* A label that has been registered with except.c to be the - landing pad for this try block. */ - tree eh_label; - /* True if it is possible to fall out the bottom of the try block. Cleared if the fallthru is converted to a goto. */ bool may_fallthru; @@ -429,7 +429,7 @@ struct leh_tf_state bool may_throw; }; -static gimple_seq lower_eh_filter (struct leh_state *, gimple); +static gimple_seq lower_eh_must_not_throw (struct leh_state *, gimple); /* Search for STMT in the goto queue. Return the replacement, or null if the statement isn't in the queue. */ @@ -810,7 +810,7 @@ do_goto_redirection (struct goto_queue_node *q, tree finlab, gimple_seq mod, if (!q->repl_stmt) q->repl_stmt = gimple_seq_alloc (); - q->cont_stmt = gimple_build_goto (VEC_index (tree, tf->dest_array,q->index)); + q->cont_stmt = gimple_build_goto (VEC_index (tree, tf->dest_array, q->index)); if (mod) gimple_seq_add_seq (&q->repl_stmt, mod); @@ -819,17 +819,76 @@ do_goto_redirection (struct goto_queue_node *q, tree finlab, gimple_seq mod, gimple_seq_add_stmt (&q->repl_stmt, x); } +/* Emit a standard landing pad sequence into SEQ for REGION. */ + +static void +emit_post_landing_pad (gimple_seq *seq, eh_region region) +{ + eh_landing_pad lp = region->landing_pads; + gimple x; + + if (lp == NULL) + lp = gen_eh_landing_pad (region); + + lp->post_landing_pad = create_artificial_label (UNKNOWN_LOCATION); + EH_LANDING_PAD_NR (lp->post_landing_pad) = lp->index; + + x = gimple_build_label (lp->post_landing_pad); + gimple_seq_add_stmt (seq, x); +} + +/* Emit a RESX statement into SEQ for REGION. */ + +static void +emit_resx (gimple_seq *seq, eh_region region) +{ + gimple x = gimple_build_resx (region->index); + gimple_seq_add_stmt (seq, x); + if (region->outer) + record_stmt_eh_region (region->outer, x); +} + +/* Emit an EH_DISPATCH statement into SEQ for REGION. */ + +static void +emit_eh_dispatch (gimple_seq *seq, eh_region region) +{ + gimple x = gimple_build_eh_dispatch (region->index); + gimple_seq_add_stmt (seq, x); +} + +/* Note that the current EH region may contain a throw, or a + call to a function which itself may contain a throw. */ + +static void +note_eh_region_may_contain_throw (eh_region region) +{ + while (!bitmap_bit_p (eh_region_may_contain_throw, region->index)) + { + bitmap_set_bit (eh_region_may_contain_throw, region->index); + region = region->outer; + if (region == NULL) + break; + } +} + /* We want to transform try { body; } catch { stuff; } to - body; goto over; lab: stuff; over: - - TP is a GIMPLE_TRY node. LAB is the label that + normal_seqence: + body; + over: + eh_seqence: + landing_pad: + stuff; + goto over; + + TP is a GIMPLE_TRY node. REGION is the region whose post_landing_pad should be placed before the second operand, or NULL. OVER is an existing label that should be put at the exit, or NULL. */ static gimple_seq -frob_into_branch_around (gimple tp, tree lab, tree over) +frob_into_branch_around (gimple tp, eh_region region, tree over) { gimple x; gimple_seq cleanup, result; @@ -838,21 +897,17 @@ frob_into_branch_around (gimple tp, tree lab, tree over) cleanup = gimple_try_cleanup (tp); result = gimple_try_eval (tp); - if (gimple_seq_may_fallthru (result)) + if (region) + emit_post_landing_pad (&eh_seq, region); + + if (gimple_seq_may_fallthru (cleanup)) { if (!over) over = create_artificial_label (loc); x = gimple_build_goto (over); - gimple_seq_add_stmt (&result, x); + gimple_seq_add_stmt (&cleanup, x); } - - if (lab) - { - x = gimple_build_label (lab); - gimple_seq_add_stmt (&result, x); - } - - gimple_seq_add_seq (&result, cleanup); + gimple_seq_add_seq (&eh_seq, cleanup); if (over) { @@ -928,44 +983,21 @@ honor_protect_cleanup_actions (struct leh_state *outer_state, struct leh_state *this_state, struct leh_tf_state *tf) { - gimple protect_cleanup_actions; + tree protect_cleanup_actions; gimple_stmt_iterator gsi; bool finally_may_fallthru; gimple_seq finally; gimple x; /* First check for nothing to do. */ - if (lang_protect_cleanup_actions) - protect_cleanup_actions = lang_protect_cleanup_actions (); - else - protect_cleanup_actions = NULL; + if (lang_protect_cleanup_actions == NULL) + return; + protect_cleanup_actions = lang_protect_cleanup_actions (); + if (protect_cleanup_actions == NULL) + return; finally = gimple_try_cleanup (tf->top_p); - - /* If the EH case of the finally block can fall through, this may be a - structure of the form - try { - try { - throw ...; - } cleanup { - try { - throw ...; - } catch (...) { - } - } - } catch (...) { - yyy; - } - E.g. with an inline destructor with an embedded try block. In this - case we must save the runtime EH data around the nested exception. - - This complication means that any time the previous runtime data might - be used (via fallthru from the finally) we handle the eh case here, - whether or not protect_cleanup_actions is active. */ - finally_may_fallthru = gimple_seq_may_fallthru (finally); - if (!finally_may_fallthru && !protect_cleanup_actions) - return; /* Duplicate the FINALLY block. Only need to do this for try-finally, and not for cleanups. */ @@ -981,8 +1013,7 @@ honor_protect_cleanup_actions (struct leh_state *outer_state, MUST_NOT_THROW filter. */ gsi = gsi_start (finally); x = gsi_stmt (gsi); - if (protect_cleanup_actions - && gimple_code (x) == GIMPLE_TRY + if (gimple_code (x) == GIMPLE_TRY && gimple_try_kind (x) == GIMPLE_TRY_CATCH && gimple_try_catch_is_cleanup (x)) { @@ -990,77 +1021,17 @@ honor_protect_cleanup_actions (struct leh_state *outer_state, gsi_remove (&gsi, false); } - /* Resume execution after the exception. Adding this now lets - lower_eh_filter not add unnecessary gotos, as it is clear that - we never fallthru from this copy of the finally block. */ - if (finally_may_fallthru) - { - tree save_eptr, save_filt; - tree tmp; - - save_eptr = create_tmp_var (ptr_type_node, "save_eptr"); - save_filt = create_tmp_var (integer_type_node, "save_filt"); - - gsi = gsi_start (finally); - tmp = build0 (EXC_PTR_EXPR, ptr_type_node); - x = gimple_build_assign (save_eptr, tmp); - gsi_insert_before (&gsi, x, GSI_CONTINUE_LINKING); - - tmp = build0 (FILTER_EXPR, integer_type_node); - x = gimple_build_assign (save_filt, tmp); - gsi_insert_before (&gsi, x, GSI_CONTINUE_LINKING); - - gsi = gsi_last (finally); - tmp = build0 (EXC_PTR_EXPR, ptr_type_node); - x = gimple_build_assign (tmp, save_eptr); - gsi_insert_after (&gsi, x, GSI_CONTINUE_LINKING); - - tmp = build0 (FILTER_EXPR, integer_type_node); - x = gimple_build_assign (tmp, save_filt); - gsi_insert_after (&gsi, x, GSI_CONTINUE_LINKING); - - x = gimple_build_resx (get_eh_region_number (tf->region)); - gsi_insert_after (&gsi, x, GSI_CONTINUE_LINKING); - } - /* Wrap the block with protect_cleanup_actions as the action. */ - if (protect_cleanup_actions) - { - gimple_seq seq = NULL, failure = NULL; - - gimple_seq_add_stmt (&failure, protect_cleanup_actions); - x = gimple_build_eh_filter (NULL, failure); - gimple_eh_filter_set_must_not_throw (x, 1); - - gimple_seq_add_stmt (&seq, x); - x = gimple_build_try (finally, seq, GIMPLE_TRY_CATCH); - finally = lower_eh_filter (outer_state, x); - } - else - lower_eh_constructs_1 (outer_state, finally); - - /* Hook this up to the end of the existing try block. If we - previously fell through the end, we'll have to branch around. - This means adding a new goto, and adding it to the queue. */ - - gsi = gsi_last (gimple_try_eval (tf->top_p)); - - if (tf->may_fallthru) - { - tree tmp; - tmp = lower_try_finally_fallthru_label (tf); - x = gimple_build_goto (tmp); - gsi_insert_after (&gsi, x, GSI_CONTINUE_LINKING); - - if (this_state) - maybe_record_in_goto_queue (this_state, x); - - tf->may_fallthru = false; - } - - x = gimple_build_label (tf->eh_label); - gsi_insert_after (&gsi, x, GSI_CONTINUE_LINKING); - gsi_insert_seq_after (&gsi, finally, GSI_CONTINUE_LINKING); + x = gimple_build_eh_must_not_throw (protect_cleanup_actions); + x = gimple_build_try (finally, gimple_seq_alloc_with_stmt (x), + GIMPLE_TRY_CATCH); + finally = lower_eh_must_not_throw (outer_state, x); + + /* Drop all of this into the exception sequence. */ + emit_post_landing_pad (&eh_seq, tf->region); + gimple_seq_add_seq (&eh_seq, finally); + if (finally_may_fallthru) + emit_resx (&eh_seq, tf->region); /* Having now been handled, EH isn't to be considered with the rest of the outgoing edges. */ @@ -1081,10 +1052,7 @@ lower_try_finally_nofallthru (struct leh_state *state, gimple_seq finally; struct goto_queue_node *q, *qe; - if (tf->may_throw) - lab = tf->eh_label; - else - lab = create_artificial_label (gimple_location (tf->try_finally_expr)); + lab = create_artificial_label (gimple_location (tf->try_finally_expr)); /* We expect that tf->top_p is a GIMPLE_TRY. */ finally = gimple_try_cleanup (tf->top_p); @@ -1106,6 +1074,14 @@ lower_try_finally_nofallthru (struct leh_state *state, lower_eh_constructs_1 (state, finally); gimple_seq_add_seq (&tf->top_p_seq, finally); + + if (tf->may_throw) + { + emit_post_landing_pad (&eh_seq, tf->region); + + x = gimple_build_goto (lab); + gimple_seq_add_stmt (&eh_seq, x); + } } /* A subroutine of lower_try_finally. We have determined that there is @@ -1130,16 +1106,9 @@ lower_try_finally_onedest (struct leh_state *state, struct leh_tf_state *tf) { /* Only reachable via the exception edge. Add the given label to the head of the FINALLY block. Append a RESX at the end. */ - - x = gimple_build_label (tf->eh_label); - gimple_seq_add_stmt (&tf->top_p_seq, x); - - gimple_seq_add_seq (&tf->top_p_seq, finally); - - x = gimple_build_resx (get_eh_region_number (tf->region)); - - gimple_seq_add_stmt (&tf->top_p_seq, x); - + emit_post_landing_pad (&eh_seq, tf->region); + gimple_seq_add_seq (&eh_seq, finally); + emit_resx (&eh_seq, tf->region); return; } @@ -1223,15 +1192,13 @@ lower_try_finally_copy (struct leh_state *state, struct leh_tf_state *tf) if (tf->may_throw) { - x = gimple_build_label (tf->eh_label); - gimple_seq_add_stmt (&new_stmt, x); + emit_post_landing_pad (&eh_seq, tf->region); seq = lower_try_finally_dup_block (finally, state); lower_eh_constructs_1 (state, seq); - gimple_seq_add_seq (&new_stmt, seq); + gimple_seq_add_seq (&eh_seq, seq); - x = gimple_build_resx (get_eh_region_number (tf->region)); - gimple_seq_add_stmt (&new_stmt, x); + emit_resx (&eh_seq, tf->region); } if (tf->goto_queue) @@ -1301,7 +1268,7 @@ lower_try_finally_copy (struct leh_state *state, struct leh_tf_state *tf) else do_goto_redirection (q, lab, NULL, tf); } - + replace_goto_queue (tf); free (labels); } @@ -1375,20 +1342,13 @@ lower_try_finally_switch (struct leh_state *state, struct leh_tf_state *tf) if (tf->may_fallthru) { - x = gimple_build_assign (finally_tmp, build_int_cst (integer_type_node, - fallthru_index)); + x = gimple_build_assign (finally_tmp, + build_int_cst (NULL, fallthru_index)); gimple_seq_add_stmt (&tf->top_p_seq, x); - if (tf->may_throw) - { - x = gimple_build_goto (finally_label); - gimple_seq_add_stmt (&tf->top_p_seq, x); - } - - last_case = build3 (CASE_LABEL_EXPR, void_type_node, - build_int_cst (NULL_TREE, fallthru_index), NULL, - create_artificial_label (tf_loc)); + build_int_cst (NULL, fallthru_index), + NULL, create_artificial_label (tf_loc)); VEC_quick_push (tree, case_label_vec, last_case); last_case_index++; @@ -1402,23 +1362,24 @@ lower_try_finally_switch (struct leh_state *state, struct leh_tf_state *tf) if (tf->may_throw) { - x = gimple_build_label (tf->eh_label); - gimple_seq_add_stmt (&tf->top_p_seq, x); + emit_post_landing_pad (&eh_seq, tf->region); - x = gimple_build_assign (finally_tmp, build_int_cst (integer_type_node, - eh_index)); - gimple_seq_add_stmt (&tf->top_p_seq, x); + x = gimple_build_assign (finally_tmp, + build_int_cst (NULL, eh_index)); + gimple_seq_add_stmt (&eh_seq, x); + + x = gimple_build_goto (finally_label); + gimple_seq_add_stmt (&eh_seq, x); last_case = build3 (CASE_LABEL_EXPR, void_type_node, - build_int_cst (NULL_TREE, eh_index), NULL, - create_artificial_label (tf_loc)); + build_int_cst (NULL, eh_index), + NULL, create_artificial_label (tf_loc)); VEC_quick_push (tree, case_label_vec, last_case); last_case_index++; x = gimple_build_label (CASE_LABEL (last_case)); - gimple_seq_add_stmt (&switch_body, x); - x = gimple_build_resx (get_eh_region_number (tf->region)); - gimple_seq_add_stmt (&switch_body, x); + gimple_seq_add_stmt (&eh_seq, x); + emit_resx (&eh_seq, tf->region); } x = gimple_build_label (finally_label); @@ -1443,8 +1404,7 @@ lower_try_finally_switch (struct leh_state *state, struct leh_tf_state *tf) if (q->index < 0) { x = gimple_build_assign (finally_tmp, - build_int_cst (integer_type_node, - return_index)); + build_int_cst (NULL, return_index)); gimple_seq_add_stmt (&mod, x); do_return_redirection (q, finally_label, mod, &return_val); switch_id = return_index; @@ -1452,7 +1412,7 @@ lower_try_finally_switch (struct leh_state *state, struct leh_tf_state *tf) else { x = gimple_build_assign (finally_tmp, - build_int_cst (integer_type_node, q->index)); + build_int_cst (NULL, q->index)); gimple_seq_add_stmt (&mod, x); do_goto_redirection (q, finally_label, mod, tf); switch_id = q->index; @@ -1465,11 +1425,11 @@ lower_try_finally_switch (struct leh_state *state, struct leh_tf_state *tf) tree case_lab; void **slot; case_lab = build3 (CASE_LABEL_EXPR, void_type_node, - build_int_cst (NULL_TREE, switch_id), NULL, - NULL); + build_int_cst (NULL, switch_id), + NULL, NULL); /* We store the cont_stmt in the pointer map, so that we can recover it in the loop below. We don't create the new label while - walking the goto_queue because pointers don't offer a stable + walking the goto_queue because pointers don't offer a stable order. */ if (!cont_map) cont_map = pointer_map_create (); @@ -1577,7 +1537,6 @@ lower_try_finally (struct leh_state *state, gimple tp) struct leh_tf_state this_tf; struct leh_state this_state; int ndests; - location_t tf_loc = gimple_location (tp); /* Process the try block. */ @@ -1586,12 +1545,12 @@ lower_try_finally (struct leh_state *state, gimple tp) this_tf.top_p = tp; this_tf.outer = state; if (using_eh_for_cleanups_p) - this_tf.region - = gen_eh_region_cleanup (state->cur_region); + this_tf.region = gen_eh_region_cleanup (state->cur_region); else this_tf.region = NULL; this_state.cur_region = this_tf.region; + this_state.ehp_region = state->ehp_region; this_state.tf = &this_tf; lower_eh_constructs_1 (&this_state, gimple_try_eval(tp)); @@ -1601,13 +1560,10 @@ lower_try_finally (struct leh_state *state, gimple tp) /* Determine if any exceptions are possible within the try block. */ if (using_eh_for_cleanups_p) - this_tf.may_throw = get_eh_region_may_contain_throw (this_tf.region); + this_tf.may_throw = bitmap_bit_p (eh_region_may_contain_throw, + this_tf.region->index); if (this_tf.may_throw) - { - this_tf.eh_label = create_artificial_label (tf_loc); - set_eh_region_tree_label (this_tf.region, this_tf.eh_label); - honor_protect_cleanup_actions (state, &this_state, &this_tf); - } + honor_protect_cleanup_actions (state, &this_state, &this_tf); /* Determine how many edges (still) reach the finally block. Or rather, how many destinations are reached by the finally block. Use this to @@ -1663,58 +1619,65 @@ lower_try_finally (struct leh_state *state, gimple tp) static gimple_seq lower_catch (struct leh_state *state, gimple tp) { - struct eh_region_d *try_region; + eh_region try_region; struct leh_state this_state; gimple_stmt_iterator gsi; tree out_label; + gimple_seq new_seq; + gimple x; location_t try_catch_loc = gimple_location (tp); try_region = gen_eh_region_try (state->cur_region); + + this_state = *state; this_state.cur_region = try_region; - this_state.tf = state->tf; lower_eh_constructs_1 (&this_state, gimple_try_eval (tp)); - if (!get_eh_region_may_contain_throw (try_region)) - { - return gimple_try_eval (tp); - } + if (!bitmap_bit_p (eh_region_may_contain_throw, try_region->index)) + return gimple_try_eval (tp); + + new_seq = NULL; + emit_eh_dispatch (&new_seq, try_region); + emit_resx (&new_seq, try_region); + + this_state.cur_region = state->cur_region; + this_state.ehp_region = try_region; out_label = NULL; - for (gsi = gsi_start (gimple_try_cleanup (tp)); !gsi_end_p (gsi); ) + for (gsi = gsi_start (gimple_try_cleanup (tp)); + !gsi_end_p (gsi); + gsi_next (&gsi)) { - struct eh_region_d *catch_region; - tree eh_label; - gimple x, gcatch; + eh_catch c; + gimple gcatch; + gimple_seq handler; gcatch = gsi_stmt (gsi); - catch_region = gen_eh_region_catch (try_region, - gimple_catch_types (gcatch)); + c = gen_eh_region_catch (try_region, gimple_catch_types (gcatch)); - this_state.cur_region = catch_region; - lower_eh_constructs_1 (&this_state, gimple_catch_handler (gcatch)); + handler = gimple_catch_handler (gcatch); + lower_eh_constructs_1 (&this_state, handler); - eh_label = create_artificial_label (try_catch_loc); - set_eh_region_tree_label (catch_region, eh_label); + c->label = create_artificial_label (UNKNOWN_LOCATION); + x = gimple_build_label (c->label); + gimple_seq_add_stmt (&new_seq, x); - x = gimple_build_label (eh_label); - gsi_insert_before (&gsi, x, GSI_SAME_STMT); + gimple_seq_add_seq (&new_seq, handler); - if (gimple_seq_may_fallthru (gimple_catch_handler (gcatch))) + if (gimple_seq_may_fallthru (new_seq)) { if (!out_label) out_label = create_artificial_label (try_catch_loc); x = gimple_build_goto (out_label); - gimple_seq_add_stmt (gimple_catch_handler_ptr (gcatch), x); + gimple_seq_add_stmt (&new_seq, x); } - - gsi_insert_seq_before (&gsi, gimple_catch_handler (gcatch), - GSI_SAME_STMT); - gsi_remove (&gsi, false); } - return frob_into_branch_around (tp, NULL, out_label); + gimple_try_set_cleanup (tp, new_seq); + + return frob_into_branch_around (tp, try_region, out_label); } /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with a @@ -1725,34 +1688,70 @@ static gimple_seq lower_eh_filter (struct leh_state *state, gimple tp) { struct leh_state this_state; - struct eh_region_d *this_region; - gimple inner; - tree eh_label; + eh_region this_region; + gimple inner, x; + gimple_seq new_seq; inner = gimple_seq_first_stmt (gimple_try_cleanup (tp)); - if (gimple_eh_filter_must_not_throw (inner)) - this_region = gen_eh_region_must_not_throw (state->cur_region); - else - this_region = gen_eh_region_allowed (state->cur_region, - gimple_eh_filter_types (inner)); + this_region = gen_eh_region_allowed (state->cur_region, + gimple_eh_filter_types (inner)); this_state = *state; this_state.cur_region = this_region; lower_eh_constructs_1 (&this_state, gimple_try_eval (tp)); - if (!get_eh_region_may_contain_throw (this_region)) - { - return gimple_try_eval (tp); - } + if (!bitmap_bit_p (eh_region_may_contain_throw, this_region->index)) + return gimple_try_eval (tp); + + new_seq = NULL; + this_state.cur_region = state->cur_region; + this_state.ehp_region = this_region; + + emit_eh_dispatch (&new_seq, this_region); + emit_resx (&new_seq, this_region); + + this_region->u.allowed.label = create_artificial_label (UNKNOWN_LOCATION); + x = gimple_build_label (this_region->u.allowed.label); + gimple_seq_add_stmt (&new_seq, x); + + lower_eh_constructs_1 (&this_state, gimple_eh_filter_failure (inner)); + gimple_seq_add_seq (&new_seq, gimple_eh_filter_failure (inner)); + + gimple_try_set_cleanup (tp, new_seq); + + return frob_into_branch_around (tp, this_region, NULL); +} - lower_eh_constructs_1 (state, gimple_eh_filter_failure (inner)); - gimple_try_set_cleanup (tp, gimple_eh_filter_failure (inner)); +/* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with + an GIMPLE_EH_MUST_NOT_THROW to a sequence of labels and blocks, + plus the exception region trees that record all the magic. */ - eh_label = create_artificial_label (gimple_location (inner)); - set_eh_region_tree_label (this_region, eh_label); +static gimple_seq +lower_eh_must_not_throw (struct leh_state *state, gimple tp) +{ + struct leh_state this_state; + eh_region this_region; + gimple inner; + + inner = gimple_seq_first_stmt (gimple_try_cleanup (tp)); + + this_region = gen_eh_region_must_not_throw (state->cur_region); + this_region->u.must_not_throw.failure_decl + = gimple_eh_must_not_throw_fndecl (inner); + this_region->u.must_not_throw.failure_loc = gimple_location (tp); - return frob_into_branch_around (tp, eh_label, NULL); + /* In order to get mangling applied to this decl, we must mark it + used now. Otherwise, pass_ipa_free_lang_data won't think it + needs to happen. */ + TREE_USED (this_region->u.must_not_throw.failure_decl) = 1; + + this_state = *state; + this_state.cur_region = this_region; + + lower_eh_constructs_1 (&this_state, gimple_try_eval (tp)); + + return gimple_try_eval (tp); } /* Implement a cleanup expression. This is similar to try-finally, @@ -1762,7 +1761,7 @@ static gimple_seq lower_cleanup (struct leh_state *state, gimple tp) { struct leh_state this_state; - struct eh_region_d *this_region; + eh_region this_region; struct leh_tf_state fake_tf; gimple_seq result; @@ -1780,10 +1779,8 @@ lower_cleanup (struct leh_state *state, gimple tp) lower_eh_constructs_1 (&this_state, gimple_try_eval (tp)); - if (!get_eh_region_may_contain_throw (this_region)) - { - return gimple_try_eval (tp); - } + if (!bitmap_bit_p (eh_region_may_contain_throw, this_region->index)) + return gimple_try_eval (tp); /* Build enough of a try-finally state so that we can reuse honor_protect_cleanup_actions. */ @@ -1794,9 +1791,6 @@ lower_cleanup (struct leh_state *state, gimple tp) fake_tf.may_fallthru = gimple_seq_may_fallthru (gimple_try_eval (tp)); fake_tf.may_throw = true; - fake_tf.eh_label = create_artificial_label (gimple_location (tp)); - set_eh_region_tree_label (this_region, fake_tf.eh_label); - honor_protect_cleanup_actions (state, NULL, &fake_tf); if (fake_tf.may_throw) @@ -1804,8 +1798,8 @@ lower_cleanup (struct leh_state *state, gimple tp) /* In this case honor_protect_cleanup_actions had nothing to do, and we should process this normally. */ lower_eh_constructs_1 (state, gimple_try_cleanup (tp)); - result = frob_into_branch_around (tp, fake_tf.eh_label, - fake_tf.fallthru_label); + result = frob_into_branch_around (tp, this_region, + fake_tf.fallthru_label); } else { @@ -1822,9 +1816,7 @@ lower_cleanup (struct leh_state *state, gimple tp) return result; } - - -/* Main loop for lowering eh constructs. Also moves gsi to the next +/* Main loop for lowering eh constructs. Also moves gsi to the next statement. */ static void @@ -1837,6 +1829,52 @@ lower_eh_constructs_2 (struct leh_state *state, gimple_stmt_iterator *gsi) switch (gimple_code (stmt)) { case GIMPLE_CALL: + { + tree fndecl = gimple_call_fndecl (stmt); + tree rhs, lhs; + + if (fndecl && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL) + switch (DECL_FUNCTION_CODE (fndecl)) + { + case BUILT_IN_EH_POINTER: + /* The front end may have generated a call to + __builtin_eh_pointer (0) within a catch region. Replace + this zero argument with the current catch region number. */ + if (state->ehp_region) + { + tree nr = build_int_cst (NULL, state->ehp_region->index); + gimple_call_set_arg (stmt, 0, nr); + } + else + { + /* The user has dome something silly. Remove it. */ + rhs = build_int_cst (ptr_type_node, 0); + goto do_replace; + } + break; + + case BUILT_IN_EH_FILTER: + /* ??? This should never appear, but since it's a builtin it + is accessible to abuse by users. Just remove it and + replace the use with the arbitrary value zero. */ + rhs = build_int_cst (TREE_TYPE (TREE_TYPE (fndecl)), 0); + do_replace: + lhs = gimple_call_lhs (stmt); + x = gimple_build_assign (lhs, rhs); + gsi_insert_before (gsi, x, GSI_SAME_STMT); + /* FALLTHRU */ + + case BUILT_IN_EH_COPY_VALUES: + /* Likewise this should not appear. Remove it. */ + gsi_remove (gsi, true); + return; + + default: + break; + } + } + /* FALLTHRU */ + case GIMPLE_ASSIGN: /* If the stmt can throw use a new temporary for the assignment to a LHS. This makes sure the old value of the LHS is @@ -1889,6 +1927,9 @@ lower_eh_constructs_2 (struct leh_state *state, gimple_stmt_iterator *gsi) case GIMPLE_EH_FILTER: replace = lower_eh_filter (state, stmt); break; + case GIMPLE_EH_MUST_NOT_THROW: + replace = lower_eh_must_not_throw (state, stmt); + break; default: replace = lower_cleanup (state, stmt); break; @@ -1926,19 +1967,32 @@ static unsigned int lower_eh_constructs (void) { struct leh_state null_state; + gimple_seq bodyp; - gimple_seq bodyp = gimple_body (current_function_decl); + bodyp = gimple_body (current_function_decl); + if (bodyp == NULL) + return 0; finally_tree = htab_create (31, struct_ptr_hash, struct_ptr_eq, free); + eh_region_may_contain_throw = BITMAP_ALLOC (NULL); + memset (&null_state, 0, sizeof (null_state)); collect_finally_tree_1 (bodyp, NULL); - - memset (&null_state, 0, sizeof (null_state)); lower_eh_constructs_1 (&null_state, bodyp); - htab_delete (finally_tree); + /* We assume there's a return statement, or something, at the end of + the function, and thus ploping the EH sequence afterward won't + change anything. */ + gcc_assert (!gimple_seq_may_fallthru (bodyp)); + gimple_seq_add_seq (&bodyp, eh_seq); + + /* We assume that since BODYP already existed, adding EH_SEQ to it + didn't change its value, and we don't have to re-set the function. */ + gcc_assert (bodyp == gimple_body (current_function_decl)); - collect_eh_region_array (); + htab_delete (finally_tree); + BITMAP_FREE (eh_region_may_contain_throw); + eh_seq = NULL; /* If this function needs a language specific EH personality routine and the frontend didn't already set one do so now. */ @@ -1968,222 +2022,206 @@ struct gimple_opt_pass pass_lower_eh = TODO_dump_func /* todo_flags_finish */ } }; - -/* Construct EH edges for STMT. */ +/* Create the multiple edges from an EH_DISPATCH statement to all of + the possible handlers for its EH region. Return true if there's + no fallthru edge; false if there is. */ -static void -make_eh_edge (struct eh_region_d *region, void *data) +bool +make_eh_dispatch_edges (gimple stmt) { - gimple stmt; - tree lab; + eh_region r; + eh_catch c; basic_block src, dst; - stmt = (gimple) data; - lab = get_eh_region_tree_label (region); - + r = get_eh_region_from_number (gimple_eh_dispatch_region (stmt)); src = gimple_bb (stmt); - dst = label_to_block (lab); - make_edge (src, dst, EDGE_EH); -} - -/* See if STMT is call that might be inlined. */ + switch (r->type) + { + case ERT_TRY: + for (c = r->u.eh_try.first_catch; c ; c = c->next_catch) + { + dst = label_to_block (c->label); + make_edge (src, dst, 0); -static bool -inlinable_call_p (gimple stmt) -{ - tree decl; - if (gimple_code (stmt) != GIMPLE_CALL) - return false; - if (cfun->after_inlining) - return false; - /* Indirect calls can be propagated to direct call - and inlined. */ - decl = gimple_call_fndecl (stmt); - if (!decl) - return true; - if (cgraph_function_flags_ready - && cgraph_function_body_availability (cgraph_node (decl)) - < AVAIL_OVERWRITABLE) - return false; - return !DECL_UNINLINABLE (decl); -} + /* A catch-all handler doesn't have a fallthru. */ + if (c->type_list == NULL) + return false; + } + break; -void -make_eh_edges (gimple stmt) -{ - int region_nr; - bool is_resx; - bool inlinable = false; - basic_block bb; + case ERT_ALLOWED_EXCEPTIONS: + dst = label_to_block (r->u.allowed.label); + make_edge (src, dst, 0); + break; - if (gimple_code (stmt) == GIMPLE_RESX) - { - region_nr = gimple_resx_region (stmt); - is_resx = true; - } - else - { - region_nr = lookup_stmt_eh_region (stmt); - if (region_nr < 0) - return; - is_resx = false; - inlinable = inlinable_call_p (stmt); + default: + gcc_unreachable (); } - foreach_reachable_handler (region_nr, is_resx, inlinable, make_eh_edge, stmt); - - /* Make CFG profile more consistent assuming that exception will resume to first - available EH handler. In practice this makes little difference, but we get - fewer consistency errors in the dumps. */ - bb = gimple_bb (stmt); - if (is_resx && EDGE_COUNT (bb->succs)) - EDGE_SUCC (bb, 0)->probability = REG_BR_PROB_BASE; + return true; } -/* Redirect EH edge E to NEW_BB. */ +/* Create the single EH edge from STMT to its nearest landing pad, + if there is such a landing pad within the current function. */ -edge -redirect_eh_edge (edge e, basic_block new_bb) +void +make_eh_edges (gimple stmt) { - gimple stmt = gsi_stmt (gsi_last_bb (e->src)); - int region_nr, new_region_nr; - bool is_resx; - bool inlinable = false; - tree label = gimple_block_label (new_bb); - struct eh_region_d *r; + basic_block src, dst; + eh_landing_pad lp; + int lp_nr; - if (gimple_code (stmt) == GIMPLE_RESX) - { - region_nr = gimple_resx_region (stmt); - is_resx = true; - } - else - { - region_nr = lookup_stmt_eh_region (stmt); - gcc_assert (region_nr >= 0); - is_resx = false; - inlinable = inlinable_call_p (stmt); - } + lp_nr = lookup_stmt_eh_lp (stmt); + if (lp_nr <= 0) + return; - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, "Redirecting EH edge %i->%i to %i, region %i, resx %i\n", - e->src->index, e->dest->index, new_bb->index, region_nr, is_resx); - r = redirect_eh_edge_to_label (e, label, is_resx, inlinable, region_nr); - new_region_nr = get_eh_region_number (r); - if (new_region_nr != region_nr) - { - if (is_resx) - gimple_resx_set_region (stmt, new_region_nr); - else - { - remove_stmt_from_eh_region (stmt); - add_stmt_to_eh_region (stmt, new_region_nr); - } - } - e = ssa_redirect_edge (e, new_bb); - return e; + lp = get_eh_landing_pad_from_number (lp_nr); + gcc_assert (lp != NULL); + + src = gimple_bb (stmt); + dst = label_to_block (lp->post_landing_pad); + make_edge (src, dst, EDGE_EH); } -static bool mark_eh_edge_found_error; +/* Do the work in redirecting EDGE_IN to NEW_BB within the EH region tree; + do not actually perform the final edge redirection. -/* Mark edge make_eh_edge would create for given region by setting it aux - field, output error if something goes wrong. */ + CHANGE_REGION is true when we're being called from cleanup_empty_eh and + we intend to change the destination EH region as well; this means + EH_LANDING_PAD_NR must already be set on the destination block label. + If false, we're being called from generic cfg manipulation code and we + should preserve our place within the region tree. */ static void -mark_eh_edge (struct eh_region_d *region, void *data) +redirect_eh_edge_1 (edge edge_in, basic_block new_bb, bool change_region) { - gimple stmt; - tree lab; - basic_block src, dst; + eh_landing_pad old_lp, new_lp; + basic_block old_bb; + gimple throw_stmt; + int old_lp_nr, new_lp_nr; + tree old_label, new_label; + edge_iterator ei; edge e; - stmt = (gimple) data; - lab = get_eh_region_tree_label (region); + old_bb = edge_in->dest; + old_label = gimple_block_label (old_bb); + old_lp_nr = EH_LANDING_PAD_NR (old_label); + gcc_assert (old_lp_nr > 0); + old_lp = get_eh_landing_pad_from_number (old_lp_nr); - src = gimple_bb (stmt); - dst = label_to_block (lab); + throw_stmt = last_stmt (edge_in->src); + gcc_assert (lookup_stmt_eh_lp (throw_stmt) == old_lp_nr); - e = find_edge (src, dst); - if (!e) - { - error ("EH edge %i->%i is missing", src->index, dst->index); - mark_eh_edge_found_error = true; - } - else if (!(e->flags & EDGE_EH)) + new_label = gimple_block_label (new_bb); + + /* Look for an existing region that might be using NEW_BB already. */ + new_lp_nr = EH_LANDING_PAD_NR (new_label); + if (new_lp_nr) { - error ("EH edge %i->%i miss EH flag", src->index, dst->index); - mark_eh_edge_found_error = true; + new_lp = get_eh_landing_pad_from_number (new_lp_nr); + gcc_assert (new_lp); + + /* Unless CHANGE_REGION is true, the new and old landing pad + had better be associated with the same EH region. */ + gcc_assert (change_region || new_lp->region == old_lp->region); } - else if (e->aux) + else { - /* ??? might not be mistake. */ - error ("EH edge %i->%i has duplicated regions", src->index, dst->index); - mark_eh_edge_found_error = true; + new_lp = NULL; + gcc_assert (!change_region); } - else - e->aux = (void *)1; -} - -/* Verify that BB containing STMT as the last statement, has precisely the - edges that make_eh_edges would create. */ -bool -verify_eh_edges (gimple stmt) -{ - int region_nr; - bool is_resx; - basic_block bb = gimple_bb (stmt); - edge_iterator ei; - edge e; - bool inlinable = false; + /* Notice when we redirect the last EH edge away from OLD_BB. */ + FOR_EACH_EDGE (e, ei, old_bb->preds) + if (e != edge_in && (e->flags & EDGE_EH)) + break; - FOR_EACH_EDGE (e, ei, bb->succs) - gcc_assert (!e->aux); - mark_eh_edge_found_error = false; - if (gimple_code (stmt) == GIMPLE_RESX) + if (new_lp) { - region_nr = gimple_resx_region (stmt); - is_resx = true; + /* NEW_LP already exists. If there are still edges into OLD_LP, + there's nothing to do with the EH tree. If there are no more + edges into OLD_LP, then we want to remove OLD_LP as it is unused. + If CHANGE_REGION is true, then our caller is expecting to remove + the landing pad. */ + if (e == NULL && !change_region) + remove_eh_landing_pad (old_lp); } else { - region_nr = lookup_stmt_eh_region (stmt); - if (region_nr < 0) - { - FOR_EACH_EDGE (e, ei, bb->succs) - if (e->flags & EDGE_EH) - { - error ("BB %i can not throw but has EH edges", bb->index); - return true; - } - return false; - } - if (!stmt_could_throw_p (stmt)) + /* No correct landing pad exists. If there are no more edges + into OLD_LP, then we can simply re-use the existing landing pad. + Otherwise, we have to create a new landing pad. */ + if (e == NULL) { - error ("BB %i last statement has incorrectly set region", bb->index); - return true; + EH_LANDING_PAD_NR (old_lp->post_landing_pad) = 0; + new_lp = old_lp; } - inlinable = inlinable_call_p (stmt); - is_resx = false; + else + new_lp = gen_eh_landing_pad (old_lp->region); + new_lp->post_landing_pad = new_label; + EH_LANDING_PAD_NR (new_label) = new_lp->index; } - foreach_reachable_handler (region_nr, is_resx, inlinable, mark_eh_edge, stmt); - FOR_EACH_EDGE (e, ei, bb->succs) + /* Maybe move the throwing statement to the new region. */ + if (old_lp != new_lp) + { + remove_stmt_from_eh_lp (throw_stmt); + add_stmt_to_eh_lp (throw_stmt, new_lp->index); + } +} + +/* Redirect EH edge E to NEW_BB. */ + +edge +redirect_eh_edge (edge edge_in, basic_block new_bb) +{ + redirect_eh_edge_1 (edge_in, new_bb, false); + return ssa_redirect_edge (edge_in, new_bb); +} + +/* This is a subroutine of gimple_redirect_edge_and_branch. Update the + labels for redirecting a non-fallthru EH_DISPATCH edge E to NEW_BB. + The actual edge update will happen in the caller. */ + +void +redirect_eh_dispatch_edge (gimple stmt, edge e, basic_block new_bb) +{ + tree new_lab = gimple_block_label (new_bb); + bool any_changed = false; + basic_block old_bb; + eh_region r; + eh_catch c; + + r = get_eh_region_from_number (gimple_eh_dispatch_region (stmt)); + switch (r->type) { - if ((e->flags & EDGE_EH) && !e->aux) + case ERT_TRY: + for (c = r->u.eh_try.first_catch; c ; c = c->next_catch) { - error ("unnecessary EH edge %i->%i", bb->index, e->dest->index); - mark_eh_edge_found_error = true; - return true; + old_bb = label_to_block (c->label); + if (old_bb == e->dest) + { + c->label = new_lab; + any_changed = true; + } } - e->aux = NULL; + break; + + case ERT_ALLOWED_EXCEPTIONS: + old_bb = label_to_block (r->u.allowed.label); + gcc_assert (old_bb == e->dest); + r->u.allowed.label = new_lab; + any_changed = true; + break; + + default: + gcc_unreachable (); } - return mark_eh_edge_found_error; + gcc_assert (any_changed); } - /* Helper function for operation_could_trap_p and stmt_could_throw_p. */ @@ -2307,7 +2345,7 @@ tree_could_trap_p (tree expr) if (!expr) return false; - + code = TREE_CODE (expr); t = TREE_TYPE (expr); @@ -2349,20 +2387,16 @@ tree_could_trap_p (tree expr) base = TREE_OPERAND (expr, 0); if (tree_could_trap_p (base)) return true; - if (TREE_THIS_NOTRAP (expr)) return false; - return !range_in_array_bounds_p (expr); case ARRAY_REF: base = TREE_OPERAND (expr, 0); if (tree_could_trap_p (base)) return true; - if (TREE_THIS_NOTRAP (expr)) return false; - return !in_array_bounds_p (expr); case INDIRECT_REF: @@ -2373,7 +2407,6 @@ tree_could_trap_p (tree expr) case ASM_EXPR: return TREE_THIS_VOLATILE (expr); - case CALL_EXPR: t = get_callee_fndecl (expr); /* Assume that calls to weak functions may trap. */ @@ -2440,35 +2473,33 @@ stmt_could_throw_1_p (gimple stmt) bool stmt_could_throw_p (gimple stmt) { - enum gimple_code code; - if (!flag_exceptions) return false; /* The only statements that can throw an exception are assignments, - conditionals, calls and asms. */ - code = gimple_code (stmt); - if (code != GIMPLE_ASSIGN - && code != GIMPLE_COND - && code != GIMPLE_CALL - && code != GIMPLE_ASM) - return false; + conditionals, calls, resx, and asms. */ + switch (gimple_code (stmt)) + { + case GIMPLE_RESX: + return true; - /* If exceptions can only be thrown by function calls and STMT is not a - GIMPLE_CALL, the statement cannot throw. */ - if (!flag_non_call_exceptions && code != GIMPLE_CALL) - return false; + case GIMPLE_CALL: + return !gimple_call_nothrow_p (stmt); - if (code == GIMPLE_ASSIGN || code == GIMPLE_COND) - return stmt_could_throw_1_p (stmt); - else if (is_gimple_call (stmt)) - return (gimple_call_flags (stmt) & ECF_NOTHROW) == 0; - else if (gimple_code (stmt) == GIMPLE_ASM) - return (gimple_asm_volatile_p (stmt)); - else - gcc_unreachable (); + case GIMPLE_ASSIGN: + case GIMPLE_COND: + if (!flag_non_call_exceptions) + return false; + return stmt_could_throw_1_p (stmt); - return false; + case GIMPLE_ASM: + if (!flag_non_call_exceptions) + return false; + return gimple_asm_volatile_p (stmt); + + default: + return false; + } } @@ -2482,8 +2513,8 @@ tree_could_throw_p (tree t) if (TREE_CODE (t) == MODIFY_EXPR) { if (flag_non_call_exceptions - && tree_could_trap_p (TREE_OPERAND (t, 0))) - return true; + && tree_could_trap_p (TREE_OPERAND (t, 0))) + return true; t = TREE_OPERAND (t, 1); } @@ -2502,25 +2533,13 @@ tree_could_throw_p (tree t) bool stmt_can_throw_external (gimple stmt) { - int region_nr; - bool is_resx = false; - bool inlinable_call = false; + int lp_nr; if (!stmt_could_throw_p (stmt)) return false; - if (gimple_code (stmt) == GIMPLE_RESX) - { - region_nr = gimple_resx_region (stmt); - is_resx = true; - } - else - region_nr = lookup_stmt_eh_region (stmt); - - if (region_nr < 0) - return true; - - return can_throw_external_1 (region_nr, is_resx, inlinable_call); + lp_nr = lookup_stmt_eh_lp (stmt); + return lp_nr == 0; } /* Return true if STMT can throw an exception that is caught within @@ -2529,49 +2548,56 @@ stmt_can_throw_external (gimple stmt) bool stmt_can_throw_internal (gimple stmt) { - int region_nr; - bool is_resx = false; - bool inlinable_call = false; + int lp_nr; - if (gimple_code (stmt) == GIMPLE_RESX) - { - region_nr = gimple_resx_region (stmt); - is_resx = true; - } - else - { - region_nr = lookup_stmt_eh_region (stmt); - inlinable_call = inlinable_call_p (stmt); - } - - if (region_nr < 0) + if (!stmt_could_throw_p (stmt)) return false; - return can_throw_internal_1 (region_nr, is_resx, inlinable_call); + lp_nr = lookup_stmt_eh_lp (stmt); + return lp_nr > 0; +} + +/* Given a statement STMT in IFUN, if STMT can no longer throw, then + remove any entry it might have from the EH table. Return true if + any change was made. */ + +bool +maybe_clean_eh_stmt_fn (struct function *ifun, gimple stmt) +{ + if (stmt_could_throw_p (stmt)) + return false; + return remove_stmt_from_eh_lp_fn (ifun, stmt); } +/* Likewise, but always use the current function. */ + +bool +maybe_clean_eh_stmt (gimple stmt) +{ + return maybe_clean_eh_stmt_fn (cfun, stmt); +} /* Given a statement OLD_STMT and a new statement NEW_STMT that has replaced OLD_STMT in the function, remove OLD_STMT from the EH table and put NEW_STMT in the table if it should be in there. Return TRUE if a replacement was done that my require an EH edge purge. */ -bool -maybe_clean_or_replace_eh_stmt (gimple old_stmt, gimple new_stmt) +bool +maybe_clean_or_replace_eh_stmt (gimple old_stmt, gimple new_stmt) { - int region_nr = lookup_stmt_eh_region (old_stmt); + int lp_nr = lookup_stmt_eh_lp (old_stmt); - if (region_nr >= 0) + if (lp_nr != 0) { bool new_stmt_could_throw = stmt_could_throw_p (new_stmt); if (new_stmt == old_stmt && new_stmt_could_throw) return false; - remove_stmt_from_eh_region (old_stmt); + remove_stmt_from_eh_lp (old_stmt); if (new_stmt_could_throw) { - add_stmt_to_eh_region (new_stmt, region_nr); + add_stmt_to_eh_lp (new_stmt, lp_nr); return false; } else @@ -2580,6 +2606,70 @@ maybe_clean_or_replace_eh_stmt (gimple old_stmt, gimple new_stmt) return false; } + +/* Given a statement OLD_STMT in OLD_FUN and a duplicate statment NEW_STMT + in NEW_FUN, copy the EH table data from OLD_STMT to NEW_STMT. The MAP + operand is the return value of duplicate_eh_regions. */ + +bool +maybe_duplicate_eh_stmt_fn (struct function *new_fun, gimple new_stmt, + struct function *old_fun, gimple old_stmt, + struct pointer_map_t *map, int default_lp_nr) +{ + int old_lp_nr, new_lp_nr; + void **slot; + + if (!stmt_could_throw_p (new_stmt)) + return false; + + old_lp_nr = lookup_stmt_eh_lp_fn (old_fun, old_stmt); + if (old_lp_nr == 0) + { + if (default_lp_nr == 0) + return false; + new_lp_nr = default_lp_nr; + } + else if (old_lp_nr > 0) + { + eh_landing_pad old_lp, new_lp; + + old_lp = VEC_index (eh_landing_pad, old_fun->eh->lp_array, old_lp_nr); + slot = pointer_map_contains (map, old_lp); + new_lp = (eh_landing_pad) *slot; + new_lp_nr = new_lp->index; + } + else + { + eh_region old_r, new_r; + + old_r = VEC_index (eh_region, old_fun->eh->region_array, -old_lp_nr); + slot = pointer_map_contains (map, old_r); + new_r = (eh_region) *slot; + new_lp_nr = -new_r->index; + } + + add_stmt_to_eh_lp_fn (new_fun, new_stmt, new_lp_nr); + return true; +} + +/* Similar, but both OLD_STMT and NEW_STMT are within the current function, + and thus no remapping is required. */ + +bool +maybe_duplicate_eh_stmt (gimple new_stmt, gimple old_stmt) +{ + int lp_nr; + + if (!stmt_could_throw_p (new_stmt)) + return false; + + lp_nr = lookup_stmt_eh_lp (old_stmt); + if (lp_nr == 0) + return false; + + add_stmt_to_eh_lp (new_stmt, lp_nr); + return true; +} /* Returns TRUE if oneh and twoh are exception handlers (gimple_try_cleanup of GIMPLE_TRY) that are similar enough to be considered the same. Currently @@ -2616,7 +2706,7 @@ same_handler_p (gimple_seq oneh, gimple_seq twoh) for (ai = 0; ai < gimple_call_num_args (ones); ++ai) if (!operand_equal_p (gimple_call_arg (ones, ai), - gimple_call_arg (twos, ai), 0)) + gimple_call_arg (twos, ai), 0)) return false; return true; @@ -2715,12 +2805,18 @@ refactor_eh (void) return 0; } +static bool +gate_refactor_eh (void) +{ + return flag_exceptions != 0; +} + struct gimple_opt_pass pass_refactor_eh = { { GIMPLE_PASS, "ehopt", /* name */ - NULL, /* gate */ + gate_refactor_eh, /* gate */ refactor_eh, /* execute */ NULL, /* sub */ NULL, /* next */ @@ -2733,512 +2829,919 @@ struct gimple_opt_pass pass_refactor_eh = TODO_dump_func /* todo_flags_finish */ } }; + +/* At the end of gimple optimization, we can lower RESX. */ -/* Walk statements, see what regions are really references and remove unreachable ones. */ +static bool +lower_resx (basic_block bb, gimple stmt, struct pointer_map_t *mnt_map) +{ + int lp_nr; + eh_region src_r, dst_r; + gimple_stmt_iterator gsi; + gimple x; + tree fn, src_nr; + bool ret = false; -static void -tree_remove_unreachable_handlers (void) + lp_nr = lookup_stmt_eh_lp (stmt); + if (lp_nr != 0) + dst_r = get_eh_region_from_lp_number (lp_nr); + else + dst_r = NULL; + + src_r = get_eh_region_from_number (gimple_resx_region (stmt)); + src_nr = build_int_cst (NULL, src_r->index); + gsi = gsi_last_bb (bb); + + if (dst_r) + { + /* When we have a destination region, we resolve this by copying + the excptr and filter values into place, and changing the edge + to immediately after the landing pad. */ + edge e; + + if (lp_nr < 0) + { + basic_block new_bb; + void **slot; + tree lab; + + /* We are resuming into a MUST_NOT_CALL region. Expand a call to + the failure decl into a new block, if needed. */ + gcc_assert (dst_r->type == ERT_MUST_NOT_THROW); + + slot = pointer_map_contains (mnt_map, dst_r); + if (slot == NULL) + { + gimple_stmt_iterator gsi2; + + new_bb = create_empty_bb (bb); + lab = gimple_block_label (new_bb); + gsi2 = gsi_start_bb (new_bb); + + fn = dst_r->u.must_not_throw.failure_decl; + x = gimple_build_call (fn, 0); + gimple_set_location (x, dst_r->u.must_not_throw.failure_loc); + gsi_insert_after (&gsi2, x, GSI_CONTINUE_LINKING); + + slot = pointer_map_insert (mnt_map, dst_r); + *slot = lab; + } + else + { + lab = (tree) *slot; + new_bb = label_to_block (lab); + } + + gcc_assert (EDGE_COUNT (bb->succs) == 0); + e = make_edge (bb, new_bb, EDGE_FALLTHRU); + e->count = bb->count; + e->probability = REG_BR_PROB_BASE; + } + else + { + edge_iterator ei; + tree dst_nr = build_int_cst (NULL, dst_r->index); + + fn = implicit_built_in_decls[BUILT_IN_EH_COPY_VALUES]; + x = gimple_build_call (fn, 2, dst_nr, src_nr); + gsi_insert_before (&gsi, x, GSI_SAME_STMT); + + /* Update the flags for the outgoing edge. */ + e = single_succ_edge (bb); + gcc_assert (e->flags & EDGE_EH); + e->flags = (e->flags & ~EDGE_EH) | EDGE_FALLTHRU; + + /* If there are no more EH users of the landing pad, delete it. */ + FOR_EACH_EDGE (e, ei, e->dest->preds) + if (e->flags & EDGE_EH) + break; + if (e == NULL) + { + eh_landing_pad lp = get_eh_landing_pad_from_number (lp_nr); + remove_eh_landing_pad (lp); + } + } + + ret = true; + } + else + { + tree var; + + /* When we don't have a destination region, this exception escapes + up the call chain. We resolve this by generating a call to the + _Unwind_Resume library function. */ + + /* ??? The ARM EABI redefines _Unwind_Resume as __cxa_end_cleanup + with no arguments for C++ and Java. Check for that. */ + switch (targetm.arm_eabi_unwinder) + { + default: + fn = implicit_built_in_decls[BUILT_IN_UNWIND_RESUME]; + if (TYPE_ARG_TYPES (TREE_TYPE (fn)) == void_list_node) + { + x = gimple_build_call (fn, 0); + gsi_insert_before (&gsi, x, GSI_SAME_STMT); + break; + } + /* FALLTHRU */ + + case 0: + fn = implicit_built_in_decls[BUILT_IN_EH_POINTER]; + x = gimple_build_call (fn, 1, src_nr); + var = create_tmp_var (ptr_type_node, NULL); + var = make_ssa_name (var, x); + gimple_call_set_lhs (x, var); + gsi_insert_before (&gsi, x, GSI_SAME_STMT); + + fn = implicit_built_in_decls[BUILT_IN_UNWIND_RESUME]; + x = gimple_build_call (fn, 1, var); + gsi_insert_before (&gsi, x, GSI_SAME_STMT); + break; + } + + gcc_assert (EDGE_COUNT (bb->succs) == 0); + } + + gsi_remove (&gsi, true); + + return ret; +} + +static unsigned +execute_lower_resx (void) { - sbitmap reachable, contains_stmt; - VEC(int,heap) * label_to_region; basic_block bb; + struct pointer_map_t *mnt_map; + bool dominance_invalidated = false; + bool any_rewritten = false; - label_to_region = label_to_region_map (); - reachable = sbitmap_alloc (num_eh_regions ()); - sbitmap_zero (reachable); - contains_stmt = sbitmap_alloc (num_eh_regions ()); - sbitmap_zero (contains_stmt); + mnt_map = pointer_map_create (); FOR_EACH_BB (bb) - { - gimple_stmt_iterator gsi; - int region; - bool has_eh_preds = bb_has_eh_pred (bb); + { + gimple last = last_stmt (bb); + if (last && is_gimple_resx (last)) + { + dominance_invalidated |= lower_resx (bb, last, mnt_map); + any_rewritten = true; + } + } + + pointer_map_destroy (mnt_map); + + if (dominance_invalidated) + { + free_dominance_info (CDI_DOMINATORS); + free_dominance_info (CDI_POST_DOMINATORS); + } + + return any_rewritten ? TODO_update_ssa_only_virtuals : 0; +} + +static bool +gate_lower_ehcontrol (void) +{ + return cfun->eh->region_tree != NULL; +} + +struct gimple_opt_pass pass_lower_resx = +{ + { + GIMPLE_PASS, + "resx", /* name */ + gate_lower_ehcontrol, /* gate */ + execute_lower_resx, /* execute */ + NULL, /* sub */ + NULL, /* next */ + 0, /* static_pass_number */ + TV_TREE_EH, /* tv_id */ + PROP_gimple_lcf, /* properties_required */ + 0, /* properties_provided */ + 0, /* properties_destroyed */ + 0, /* todo_flags_start */ + TODO_dump_func | TODO_verify_flow /* todo_flags_finish */ + } +}; + + +/* At the end of inlining, we can lower EH_DISPATCH. */ + +static void +lower_eh_dispatch (basic_block src, gimple stmt) +{ + gimple_stmt_iterator gsi; + int region_nr; + eh_region r; + tree filter, fn; + gimple x; - for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) + region_nr = gimple_eh_dispatch_region (stmt); + r = get_eh_region_from_number (region_nr); + + gsi = gsi_last_bb (src); + + switch (r->type) + { + case ERT_TRY: { - gimple stmt = gsi_stmt (gsi); + VEC (tree, heap) *labels = NULL; + tree default_label = NULL; + eh_catch c; + edge_iterator ei; + edge e; + + /* Collect the labels for a switch. Zero the post_landing_pad + field becase we'll no longer have anything keeping these labels + in existance and the optimizer will be free to merge these + blocks at will. */ + for (c = r->u.eh_try.first_catch; c ; c = c->next_catch) + { + tree tp_node, flt_node, lab = c->label; + + c->label = NULL; + tp_node = c->type_list; + flt_node = c->filter_list; - if (gimple_code (stmt) == GIMPLE_LABEL && has_eh_preds) + if (tp_node == NULL) + { + default_label = lab; + break; + } + do + { + tree t = build3 (CASE_LABEL_EXPR, void_type_node, + TREE_VALUE (flt_node), NULL, lab); + VEC_safe_push (tree, heap, labels, t); + + tp_node = TREE_CHAIN (tp_node); + flt_node = TREE_CHAIN (flt_node); + } + while (tp_node); + } + + /* Clean up the edge flags. */ + FOR_EACH_EDGE (e, ei, src->succs) { - int uid = LABEL_DECL_UID (gimple_label_label (stmt)); - int region; + if (e->flags & EDGE_FALLTHRU) + { + /* If there was no catch-all, use the fallthru edge. */ + if (default_label == NULL) + default_label = gimple_block_label (e->dest); + e->flags &= ~EDGE_FALLTHRU; + } + } + gcc_assert (default_label != NULL); - for (region = VEC_index (int, label_to_region, uid); - region; region = get_next_region_sharing_label (region)) - SET_BIT (reachable, region); + /* Don't generate a switch if there's only a default case. + This is common in the form of try { A; } catch (...) { B; }. */ + if (labels == NULL) + { + e = single_succ_edge (src); + e->flags |= EDGE_FALLTHRU; } - if (gimple_code (stmt) == GIMPLE_RESX) - SET_BIT (reachable, - VEC_index (eh_region, cfun->eh->region_array, - gimple_resx_region (stmt))->region_number); - if ((region = lookup_stmt_eh_region (stmt)) >= 0) - SET_BIT (contains_stmt, region); + else + { + fn = implicit_built_in_decls[BUILT_IN_EH_FILTER]; + x = gimple_build_call (fn, 1, build_int_cst (NULL, region_nr)); + filter = create_tmp_var (TREE_TYPE (TREE_TYPE (fn)), NULL); + filter = make_ssa_name (filter, x); + gimple_call_set_lhs (x, filter); + gsi_insert_before (&gsi, x, GSI_SAME_STMT); + + /* Turn the default label into a default case. */ + default_label = build3 (CASE_LABEL_EXPR, void_type_node, + NULL, NULL, default_label); + sort_case_labels (labels); + + x = gimple_build_switch_vec (filter, default_label, labels); + gsi_insert_before (&gsi, x, GSI_SAME_STMT); + + VEC_free (tree, heap, labels); + } + } + break; + + case ERT_ALLOWED_EXCEPTIONS: + { + edge b_e = BRANCH_EDGE (src); + edge f_e = FALLTHRU_EDGE (src); + + fn = implicit_built_in_decls[BUILT_IN_EH_FILTER]; + x = gimple_build_call (fn, 1, build_int_cst (NULL, region_nr)); + filter = create_tmp_var (TREE_TYPE (TREE_TYPE (fn)), NULL); + filter = make_ssa_name (filter, x); + gimple_call_set_lhs (x, filter); + gsi_insert_before (&gsi, x, GSI_SAME_STMT); + + r->u.allowed.label = NULL; + x = gimple_build_cond (EQ_EXPR, filter, + build_int_cst (TREE_TYPE (filter), + r->u.allowed.filter), + NULL_TREE, NULL_TREE); + gsi_insert_before (&gsi, x, GSI_SAME_STMT); + + b_e->flags = b_e->flags | EDGE_TRUE_VALUE; + f_e->flags = (f_e->flags & ~EDGE_FALLTHRU) | EDGE_FALSE_VALUE; } - } + break; + + default: + gcc_unreachable (); + } + + /* Replace the EH_DISPATCH with the SWITCH or COND generated above. */ + gsi_remove (&gsi, true); +} + +static unsigned +execute_lower_eh_dispatch (void) +{ + basic_block bb; + bool any_rewritten = false; + + assign_filter_values (); + + FOR_EACH_BB (bb) + { + gimple last = last_stmt (bb); + if (last && gimple_code (last) == GIMPLE_EH_DISPATCH) + { + lower_eh_dispatch (bb, last); + any_rewritten = true; + } + } + + return any_rewritten ? TODO_update_ssa_only_virtuals : 0; +} + +struct gimple_opt_pass pass_lower_eh_dispatch = +{ + { + GIMPLE_PASS, + "ehdisp", /* name */ + gate_lower_ehcontrol, /* gate */ + execute_lower_eh_dispatch, /* execute */ + NULL, /* sub */ + NULL, /* next */ + 0, /* static_pass_number */ + TV_TREE_EH, /* tv_id */ + PROP_gimple_lcf, /* properties_required */ + 0, /* properties_provided */ + 0, /* properties_destroyed */ + 0, /* todo_flags_start */ + TODO_dump_func | TODO_verify_flow /* todo_flags_finish */ + } +}; + +/* Walk statements, see what regions are really referenced and remove + those that are unused. */ + +static void +remove_unreachable_handlers (void) +{ + sbitmap r_reachable, lp_reachable; + eh_region region; + eh_landing_pad lp; + basic_block bb; + int lp_nr, r_nr; + + r_reachable = sbitmap_alloc (VEC_length (eh_region, cfun->eh->region_array)); + lp_reachable + = sbitmap_alloc (VEC_length (eh_landing_pad, cfun->eh->lp_array)); + sbitmap_zero (r_reachable); + sbitmap_zero (lp_reachable); + + FOR_EACH_BB (bb) + { + gimple_stmt_iterator gsi = gsi_start_bb (bb); + + for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) + { + gimple stmt = gsi_stmt (gsi); + lp_nr = lookup_stmt_eh_lp (stmt); + + /* Negative LP numbers are MUST_NOT_THROW regions which + are not considered BB enders. */ + if (lp_nr < 0) + SET_BIT (r_reachable, -lp_nr); + + /* Positive LP numbers are real landing pads, are are BB enders. */ + else if (lp_nr > 0) + { + gcc_assert (gsi_one_before_end_p (gsi)); + region = get_eh_region_from_lp_number (lp_nr); + SET_BIT (r_reachable, region->index); + SET_BIT (lp_reachable, lp_nr); + } + } + } if (dump_file) { fprintf (dump_file, "Before removal of unreachable regions:\n"); dump_eh_tree (dump_file, cfun); fprintf (dump_file, "Reachable regions: "); - dump_sbitmap_file (dump_file, reachable); - fprintf (dump_file, "Regions containing insns: "); - dump_sbitmap_file (dump_file, contains_stmt); + dump_sbitmap_file (dump_file, r_reachable); + fprintf (dump_file, "Reachable landing pads: "); + dump_sbitmap_file (dump_file, lp_reachable); } - remove_unreachable_regions (reachable, contains_stmt); - sbitmap_free (reachable); - sbitmap_free (contains_stmt); - VEC_free (int, heap, label_to_region); + for (r_nr = 1; + VEC_iterate (eh_region, cfun->eh->region_array, r_nr, region); ++r_nr) + if (region && !TEST_BIT (r_reachable, r_nr)) + { + if (dump_file) + fprintf (dump_file, "Removing unreachable region %d\n", r_nr); + remove_eh_handler (region); + } + + for (lp_nr = 1; + VEC_iterate (eh_landing_pad, cfun->eh->lp_array, lp_nr, lp); ++lp_nr) + if (lp && !TEST_BIT (lp_reachable, lp_nr)) + { + if (dump_file) + fprintf (dump_file, "Removing unreachable landing pad %d\n", lp_nr); + remove_eh_landing_pad (lp); + } + if (dump_file) { fprintf (dump_file, "\n\nAfter removal of unreachable regions:\n"); dump_eh_tree (dump_file, cfun); fprintf (dump_file, "\n\n"); } + + sbitmap_free (r_reachable); + sbitmap_free (lp_reachable); + +#ifdef ENABLE_CHECKING + verify_eh_tree (cfun); +#endif } -/* Pattern match emtpy EH receiver looking like: - - save_filt.6352_662 = [filter_expr] <<<filter object>>>; - save_eptr.6351_663 = [exc_ptr_expr] <<<exception object>>>; - <<<exception object>>> = save_eptr.6351_663; - <<<filter object>>> = save_filt.6352_662; - resx 1 +/* Remove regions that do not have landing pads. This assumes + that remove_unreachable_handlers has already been run, and + that we've just manipulated the landing pads since then. */ - And various minor variants after DCE or copy propagation. - */ +static void +remove_unreachable_handlers_no_lp (void) +{ + eh_region r; + int i; -static int -tree_empty_eh_handler_p (basic_block bb) + for (i = 1; VEC_iterate (eh_region, cfun->eh->region_array, i, r); ++i) + if (r && r->landing_pads == NULL && r->type != ERT_MUST_NOT_THROW) + { + if (dump_file) + fprintf (dump_file, "Removing unreachable region %d\n", i); + remove_eh_handler (r); + } +} + +/* Undo critical edge splitting on an EH landing pad. Earlier, we + optimisticaly split all sorts of edges, including EH edges. The + optimization passes in between may not have needed them; if not, + we should undo the split. + + Recognize this case by having one EH edge incoming to the BB and + one normal edge outgoing; BB should be empty apart from the + post_landing_pad label. + + Note that this is slightly different from the empty handler case + handled by cleanup_empty_eh, in that the actual handler may yet + have actual code but the landing pad has been separated from the + handler. As such, cleanup_empty_eh relies on this transformation + having been done first. */ + +static bool +unsplit_eh (eh_landing_pad lp) { + basic_block bb = label_to_block (lp->post_landing_pad); gimple_stmt_iterator gsi; - int region; + edge e_in, e_out; + + /* Quickly check the edge counts on BB for singularity. */ + if (EDGE_COUNT (bb->preds) != 1 || EDGE_COUNT (bb->succs) != 1) + return false; + e_in = EDGE_PRED (bb, 0); + e_out = EDGE_SUCC (bb, 0); + + /* Input edge must be EH and output edge must be normal. */ + if ((e_in->flags & EDGE_EH) == 0 || (e_out->flags & EDGE_EH) != 0) + return false; + + /* The block must be empty except for the labels. */ + if (!gsi_end_p (gsi_after_labels (bb))) + return false; + + /* The destination block must not already have a landing pad + for a different region. */ + for (gsi = gsi_start_bb (e_out->dest); !gsi_end_p (gsi); gsi_next (&gsi)) + { + gimple stmt = gsi_stmt (gsi); + tree lab; + int lp_nr; + + if (gimple_code (stmt) != GIMPLE_LABEL) + break; + lab = gimple_label_label (stmt); + lp_nr = EH_LANDING_PAD_NR (lab); + if (lp_nr && get_eh_region_from_lp_number (lp_nr) != lp->region) + return false; + } + + /* ??? I can't imagine there would be PHI nodes, since by nature + of critical edge splitting this block should never have been + a dominance frontier. If cfg cleanups somehow confuse this, + due to single edges in and out we ought to have degenerate PHIs + and can easily propagate the PHI arguments. */ + gcc_assert (gimple_seq_empty_p (phi_nodes (bb))); + + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "Unsplit EH landing pad %d to block %i.\n", + lp->index, e_out->dest->index); + + /* Redirect the edge. Since redirect_eh_edge_1 expects to be moving + a successor edge, humor it. But do the real CFG change with the + predecessor of E_OUT in order to preserve the ordering of arguments + to the PHI nodes in E_OUT->DEST. */ + redirect_eh_edge_1 (e_in, e_out->dest, false); + redirect_edge_pred (e_out, e_in->src); + e_out->flags = e_in->flags; + e_out->probability = e_in->probability; + e_out->count = e_in->count; + remove_edge (e_in); + + return true; +} + +/* Examine each landing pad block and see if it matches unsplit_eh. */ + +static bool +unsplit_all_eh (void) +{ + bool changed = false; + eh_landing_pad lp; + int i; + + for (i = 1; VEC_iterate (eh_landing_pad, cfun->eh->lp_array, i, lp); ++i) + if (lp) + changed |= unsplit_eh (lp); + + return changed; +} + +/* A subroutine of cleanup_empty_eh. Redirect all EH edges incoming + to OLD_BB to NEW_BB; return true on success, false on failure. + + OLD_BB_OUT is the edge into NEW_BB from OLD_BB, so if we miss any + PHI variables from OLD_BB we can pick them up from OLD_BB_OUT. + Virtual PHIs may be deleted and marked for renaming. */ + +static bool +cleanup_empty_eh_merge_phis (basic_block new_bb, basic_block old_bb, + edge old_bb_out) +{ + gimple_stmt_iterator ngsi, ogsi; edge_iterator ei; edge e; - use_operand_p imm_use; - gimple use_stmt; - bool found = false; + bitmap rename_virts; + bitmap ophi_handled; - gsi = gsi_last_bb (bb); + FOR_EACH_EDGE (e, ei, old_bb->preds) + redirect_edge_var_map_clear (e); - /* RESX */ - if (gsi_end_p (gsi)) - return 0; - if (gimple_code (gsi_stmt (gsi)) != GIMPLE_RESX) - return 0; - region = gimple_resx_region (gsi_stmt (gsi)); + ophi_handled = BITMAP_ALLOC (NULL); + rename_virts = BITMAP_ALLOC (NULL); - /* filter_object set. */ - gsi_prev_nondebug (&gsi); - if (gsi_end_p (gsi)) - return 0; - if (gimple_code (gsi_stmt (gsi)) == GIMPLE_ASSIGN) + /* First, iterate through the PHIs on NEW_BB and set up the edge_var_map + for the edges we're going to move. */ + for (ngsi = gsi_start_phis (new_bb); !gsi_end_p (ngsi); gsi_next (&ngsi)) { - tree filter_tmp; - tree exc_ptr_tmp; + gimple ophi, nphi = gsi_stmt (ngsi); + tree nresult, nop; - if (TREE_CODE (gimple_assign_lhs (gsi_stmt (gsi))) != FILTER_EXPR) - return 0; - filter_tmp = gimple_assign_rhs1 (gsi_stmt (gsi)); + nresult = gimple_phi_result (nphi); + nop = gimple_phi_arg_def (nphi, old_bb_out->dest_idx); - /* filter_object set. */ - gsi_prev_nondebug (&gsi); - if (gsi_end_p (gsi)) - return 0; - if (gimple_code (gsi_stmt (gsi)) != GIMPLE_ASSIGN) - return 0; - if (TREE_CODE (gimple_assign_lhs (gsi_stmt (gsi))) != EXC_PTR_EXPR) - return 0; - exc_ptr_tmp = gimple_assign_rhs1 (gsi_stmt (gsi)); - - /* exc_ptr get. */ - if (TREE_CODE (exc_ptr_tmp) != EXC_PTR_EXPR) + /* Find the corresponding PHI in OLD_BB so we can forward-propagate + the source ssa_name. */ + ophi = NULL; + for (ogsi = gsi_start_phis (old_bb); !gsi_end_p (ogsi); gsi_next (&ogsi)) { - gsi_prev_nondebug (&gsi); - if (gsi_end_p (gsi)) - return 0; - if (gimple_code (gsi_stmt (gsi)) != GIMPLE_ASSIGN) - return 0; - if (TREE_CODE (gimple_assign_rhs1 (gsi_stmt (gsi))) != EXC_PTR_EXPR) - return 0; - if (exc_ptr_tmp != gimple_assign_lhs (gsi_stmt (gsi))) - return 0; - if (!single_imm_use (exc_ptr_tmp, &imm_use, &use_stmt)) - return 0; + ophi = gsi_stmt (ogsi); + if (gimple_phi_result (ophi) == nop) + break; + ophi = NULL; } - /* filter_object get. */ - if (TREE_CODE (filter_tmp) != FILTER_EXPR) + /* If we did find the corresponding PHI, copy those inputs. */ + if (ophi) + { + bitmap_set_bit (ophi_handled, SSA_NAME_VERSION (nop)); + FOR_EACH_EDGE (e, ei, old_bb->preds) + { + location_t oloc; + tree oop; + + if ((e->flags & EDGE_EH) == 0) + continue; + oop = gimple_phi_arg_def (ophi, e->dest_idx); + oloc = gimple_phi_arg_location (ophi, e->dest_idx); + redirect_edge_var_map_add (e, nresult, oop, oloc); + } + } + /* If we didn't find the PHI, but it's a VOP, remember to rename + it later, assuming all other tests succeed. */ + else if (!is_gimple_reg (nresult)) + bitmap_set_bit (rename_virts, SSA_NAME_VERSION (nresult)); + /* If we didn't find the PHI, and it's a real variable, we know + from the fact that OLD_BB is tree_empty_eh_handler_p that the + variable is unchanged from input to the block and we can simply + re-use the input to NEW_BB from the OLD_BB_OUT edge. */ + else { - gsi_prev_nondebug (&gsi); - if (gsi_end_p (gsi)) - return 0; - if (gimple_code (gsi_stmt (gsi)) != GIMPLE_ASSIGN) - return 0; - if (TREE_CODE (gimple_assign_rhs1 (gsi_stmt (gsi))) != FILTER_EXPR) - return 0; - if (filter_tmp != gimple_assign_lhs (gsi_stmt (gsi))) - return 0; - if (!single_imm_use (filter_tmp, &imm_use, &use_stmt)) - return 0; + location_t nloc + = gimple_phi_arg_location (nphi, old_bb_out->dest_idx); + FOR_EACH_EDGE (e, ei, old_bb->preds) + redirect_edge_var_map_add (e, nresult, nop, nloc); } - - /* label. */ - gsi_prev_nondebug (&gsi); - if (gsi_end_p (gsi)) - return 0; } - if (gimple_code (gsi_stmt (gsi)) != GIMPLE_LABEL) - return 0; - /* Be sure that there is at least on EH region reaching the block directly. - After EH edge redirection, it is possible that block is reached by one handler - but resumed by different. */ - FOR_EACH_EDGE (e, ei, bb->preds) - if ((e->flags & EDGE_EH)) - found = true; - if (found) - return region; - return 0; -} - -/* Return true if it is possible to remove basic block BB and propagate - through PHIs. - - This means that every PHI in BB has all uses such that they are PHIs - of basic blocks reachable througt BB and they appears only in use - reachable by the edge from BB to the block contianing the use. - - This is same as in merge-phi code, but in slightly more general setting - because BB can have multiple successors. */ + /* Second, verify that all PHIs from OLD_BB have been handled. If not, + we don't know what values from the other edges into NEW_BB to use. */ + for (ogsi = gsi_start_phis (old_bb); !gsi_end_p (ogsi); gsi_next (&ogsi)) + { + gimple ophi = gsi_stmt (ogsi); + tree oresult = gimple_phi_result (ophi); + if (!bitmap_bit_p (ophi_handled, SSA_NAME_VERSION (oresult))) + goto fail; + } -static bool -all_phis_safe_to_merge (basic_block bb) -{ - gimple_stmt_iterator si; - bool ok = true; - - for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si)) - { - gimple phi = gsi_stmt (si); - tree result = gimple_phi_result (phi); - gimple stmt; - use_operand_p imm_use; - imm_use_iterator imm_iter; - - /* If the PHI's result is never used, then we can just - ignore it. */ - if (has_zero_uses (result)) - continue; - /* We can always rebuild virtuals if needed. */ - if (!is_gimple_reg (result)) - continue; - FOR_EACH_IMM_USE_STMT (stmt, imm_iter, result) - { - if (gimple_code (stmt) != GIMPLE_PHI) + /* At this point we know that the merge will succeed. Remove the PHI + nodes for the virtuals that we want to rename. */ + if (!bitmap_empty_p (rename_virts)) + { + for (ngsi = gsi_start_phis (new_bb); !gsi_end_p (ngsi); ) + { + gimple nphi = gsi_stmt (ngsi); + tree nresult = gimple_phi_result (nphi); + if (bitmap_bit_p (rename_virts, SSA_NAME_VERSION (nresult))) { - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, - "PHI result has use in non-PHI statement.\n"); - ok = false; - BREAK_FROM_IMM_USE_STMT (imm_iter); + mark_virtual_phi_result_for_renaming (nphi); + remove_phi_node (&ngsi, true); } else - FOR_EACH_IMM_USE_ON_STMT (imm_use, imm_iter) - { - edge e; - e = gimple_phi_arg_edge (stmt, PHI_ARG_INDEX_FROM_USE (imm_use)); - if (e->src != bb) - { - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, "PHI has use in PHI not reached from" - "empty cleanup itself.\n"); - ok = false; - break; - } - } - if (!ok) - BREAK_FROM_IMM_USE_STMT (imm_iter); - } - if (!ok) - return false; + gsi_next (&ngsi); + } } - return ok; -} -static bool dominance_info_invalidated; + /* Finally, move the edges and update the PHIs. */ + for (ei = ei_start (old_bb->preds); (e = ei_safe_edge (ei)); ) + if (e->flags & EDGE_EH) + { + redirect_eh_edge_1 (e, new_bb, true); + redirect_edge_succ (e, new_bb); + flush_pending_stmts (e); + } + else + ei_next (&ei); -/* Information to pass into make_eh_edge_and_update_phi. */ + BITMAP_FREE (ophi_handled); + BITMAP_FREE (rename_virts); + return true; -struct update_info -{ - basic_block bb_to_remove, bb; - edge edge_to_remove; -}; + fail: + FOR_EACH_EDGE (e, ei, old_bb->preds) + redirect_edge_var_map_clear (e); + BITMAP_FREE (ophi_handled); + BITMAP_FREE (rename_virts); + return false; +} -/* DATA points to update-info structure. - Like make_eh_edge create EH edge from DATA->bb to basic block containing - handler of REGION. In addition also update PHI operands by copying - operands from DATA->bb_to_remove. */ +/* A subroutine of cleanup_empty_eh. Move a landing pad LP from its + old region to NEW_REGION at BB. */ static void -make_eh_edge_and_update_phi (struct eh_region_d *region, void *data) +cleanup_empty_eh_move_lp (basic_block bb, edge e_out, + eh_landing_pad lp, eh_region new_region) { - struct update_info *info = (struct update_info *) data; - edge e, e2; - tree lab; - basic_block src, dst; - gimple_stmt_iterator si; + gimple_stmt_iterator gsi; + eh_landing_pad *pp; - lab = get_eh_region_tree_label (region); + for (pp = &lp->region->landing_pads; *pp != lp; pp = &(*pp)->next_lp) + continue; + *pp = lp->next_lp; - src = info->bb; - dst = label_to_block (lab); + lp->region = new_region; + lp->next_lp = new_region->landing_pads; + new_region->landing_pads = lp; - e = find_edge (src, dst); - if (e) - { - gcc_assert (e->flags & EDGE_EH); - e->aux = e; - return; - } - dominance_info_invalidated = true; - e2 = find_edge (info->bb_to_remove, dst); - e = make_edge (src, dst, EDGE_EH); - e->aux = e; - gcc_assert (e2); - for (si = gsi_start_phis (dst); !gsi_end_p (si); gsi_next (&si)) - { - gimple phi = gsi_stmt (si); - tree use = USE_FROM_PTR (PHI_ARG_DEF_PTR_FROM_EDGE (phi, e2)); - gimple def = (TREE_CODE (use) == SSA_NAME - ? SSA_NAME_DEF_STMT (use) : NULL); + /* Delete the RESX that was matched within the empty handler block. */ + gsi = gsi_last_bb (bb); + mark_virtual_ops_for_renaming (gsi_stmt (gsi)); + gsi_remove (&gsi, true); - if (def && gimple_bb (def) == info->bb_to_remove) - { - use = USE_FROM_PTR (PHI_ARG_DEF_PTR_FROM_EDGE (def, - info->edge_to_remove)); - gcc_assert (info->bb_to_remove == info->edge_to_remove->dest); - def = TREE_CODE (use) == SSA_NAME ? SSA_NAME_DEF_STMT (use) : NULL; - gcc_assert (!def - || gimple_bb (def) != info->bb_to_remove - || !is_gimple_reg (use)); - } - SET_USE (PHI_ARG_DEF_PTR_FROM_EDGE (phi, e), use); - } + /* Clean up E_OUT for the fallthru. */ + e_out->flags = (e_out->flags & ~EDGE_EH) | EDGE_FALLTHRU; + e_out->probability = REG_BR_PROB_BASE; } -/* Make EH edges corresponding to STMT while updating PHI nodes after removal - empty cleanup BB_TO_REMOVE joined to BB containing STMT - by EDGE_TO_REMOVE. - - Return if EDGE_TO_REMOVE was really removed. It might stay reachable when - not all EH regions are cleaned up. */ +/* A subroutine of cleanup_empty_eh. Handle more complex cases of + unsplitting than unsplit_eh was prepared to handle, e.g. when + multiple incoming edges and phis are involved. */ static bool -update_eh_edges (gimple stmt, basic_block bb_to_remove, edge edge_to_remove) +cleanup_empty_eh_unsplit (basic_block bb, edge e_out, eh_landing_pad olp) { - int region_nr; - bool is_resx; - bool inlinable = false; - struct update_info info; - edge_iterator ei; - edge e; - int probability_sum = 0; - bool removed = false; + gimple_stmt_iterator gsi; + eh_landing_pad nlp; + tree lab; - info.bb_to_remove = bb_to_remove; - info.bb = gimple_bb (stmt); - info.edge_to_remove = edge_to_remove; + /* We really ought not have totally lost everything following + a landing pad label. Given that BB is empty, there had better + be a successor. */ + gcc_assert (e_out != NULL); - if (gimple_code (stmt) == GIMPLE_RESX) - { - region_nr = gimple_resx_region (stmt); - is_resx = true; - } - else + /* Look for an EH label in the successor block. */ + lab = NULL; + for (gsi = gsi_start_bb (e_out->dest); !gsi_end_p (gsi); gsi_next (&gsi)) { - region_nr = lookup_stmt_eh_region (stmt); - is_resx = false; - inlinable = inlinable_call_p (stmt); + gimple stmt = gsi_stmt (gsi); + if (gimple_code (stmt) != GIMPLE_LABEL) + break; + lab = gimple_label_label (stmt); + if (EH_LANDING_PAD_NR (lab)) + goto found; } + return false; + found: - /* First add new edges as neccesary. */ - foreach_reachable_handler (region_nr, is_resx, inlinable, - make_eh_edge_and_update_phi, &info); + /* The other label had better be part of the same EH region. Given that + we've not lowered RESX, there should be no way to have a totally empty + landing pad that crosses to another EH region. */ + nlp = get_eh_landing_pad_from_number (EH_LANDING_PAD_NR (lab)); + gcc_assert (nlp->region == olp->region); - /* And remove edges we didn't marked. */ - for (ei = ei_start (info.bb->succs); (e = ei_safe_edge (ei)); ) + /* Attempt to move the PHIs into the successor block. */ + if (cleanup_empty_eh_merge_phis (e_out->dest, bb, e_out)) { - if ((e->flags & EDGE_EH) && !e->aux) - { - dominance_info_invalidated = true; - if (e == edge_to_remove) - removed = true; - remove_edge (e); - } - else - { - e->aux = NULL; - probability_sum += e->probability; - ei_next (&ei); - } + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, + "Unsplit EH landing pad %d to block %d via lp %d.\n", + olp->index, e_out->dest->index, nlp->index); + + remove_eh_landing_pad (olp); + return true; } - /* Make CFG profile more consistent assuming that exception will resume to - first available EH handler. In practice this makes little difference, but - we get fewer consistency errors in the dumps. */ - if (is_resx && EDGE_COUNT (info.bb->succs) && !probability_sum) - EDGE_SUCC (info.bb, 0)->probability = REG_BR_PROB_BASE; - return removed; + return false; } -/* Look for basic blocks containing empty exception handler and remove them. - This is similar to jump forwarding, just across EH edges. */ +/* Examine the block associated with LP to determine if it's an empty + handler for its EH region. If so, attempt to redirect EH edges to + an outer region. Return true the CFG was updated in any way. This + is similar to jump forwarding, just across EH edges. */ static bool -cleanup_empty_eh (basic_block bb, VEC(int,heap) * label_to_region) +cleanup_empty_eh (eh_landing_pad lp) { - int region; - gimple_stmt_iterator si; + basic_block bb = label_to_block (lp->post_landing_pad); + gimple_stmt_iterator gsi; + gimple resx; + eh_region new_region; edge_iterator ei; + edge e, e_out; + bool has_non_eh_pred; + int new_lp_nr; - /* When handler of EH region winds up to be empty, we can safely - remove it. This leads to inner EH regions to be redirected - to outer one, if present in function. So we need to rebuild - EH edges in all sources. */ - if ((region = tree_empty_eh_handler_p (bb)) - && all_phis_safe_to_merge (bb)) + /* There can be zero or one edges out of BB. This is the quickest test. */ + switch (EDGE_COUNT (bb->succs)) { - edge e; - bool found = false, removed_some = false, has_non_eh_preds = false; - gimple_stmt_iterator gsi; - - /* Look for all EH regions sharing label of this block. - If they are not same as REGION, remove them and replace them - by outer region of REGION. Also note if REGION itself is one - of them. */ - - for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) - if (gimple_code (gsi_stmt (gsi)) == GIMPLE_LABEL) - { - int uid = LABEL_DECL_UID (gimple_label_label (gsi_stmt (gsi))); - int r = VEC_index (int, label_to_region, uid); - int next; + case 0: + e_out = NULL; + break; + case 1: + e_out = EDGE_SUCC (bb, 0); + break; + default: + return false; + } + gsi = gsi_after_labels (bb); - while (r) - { - next = get_next_region_sharing_label (r); - if (r == region) - found = true; - else - { - removed_some = true; - remove_eh_region_and_replace_by_outer_of (r, region); - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, "Empty EH handler %i removed and " - "replaced by %i\n", r, region); - } - r = next; - } - } - else - break; + /* Make sure to skip debug statements. */ + if (!gsi_end_p (gsi) && is_gimple_debug (gsi_stmt (gsi))) + gsi_next_nondebug (&gsi); - gcc_assert (found || removed_some); - FOR_EACH_EDGE (e, ei, bb->preds) - if (!(e->flags & EDGE_EH)) - has_non_eh_preds = true; + /* If the block is totally empty, look for more unsplitting cases. */ + if (gsi_end_p (gsi)) + return cleanup_empty_eh_unsplit (bb, e_out, lp); - /* When block is empty EH cleanup, but it is reachable via non-EH code too, - we can not remove the region it is resumed via, because doing so will - lead to redirection of its RESX edges. + /* The block should consist only of a single RESX statement. */ + resx = gsi_stmt (gsi); + if (!is_gimple_resx (resx)) + return false; + gcc_assert (gsi_one_before_end_p (gsi)); - This case will be handled later after edge forwarding if the EH cleanup - is really dead. */ + /* Determine if there are non-EH edges, or resx edges into the handler. */ + has_non_eh_pred = false; + FOR_EACH_EDGE (e, ei, bb->preds) + if (!(e->flags & EDGE_EH)) + has_non_eh_pred = true; - if (found && !has_non_eh_preds) - { - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, "Empty EH handler %i removed.\n", region); - remove_eh_region (region); - } - else if (!removed_some) - return false; + /* Find the handler that's outer of the empty handler by looking at + where the RESX instruction was vectored. */ + new_lp_nr = lookup_stmt_eh_lp (resx); + new_region = get_eh_region_from_lp_number (new_lp_nr); + /* If there's no destination region within the current function, + redirection is trivial via removing the throwing statements from + the EH region, removing the EH edges, and allowing the block + to go unreachable. */ + if (new_region == NULL) + { + gcc_assert (e_out == NULL); for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); ) - { - basic_block src = e->src; - if (!(e->flags & EDGE_EH)) - { - ei_next (&ei); - continue; - } - if (stmt_can_throw_internal (last_stmt (src))) - { - if (!update_eh_edges (last_stmt (src), bb, e)) - ei_next (&ei); - } - else + if (e->flags & EDGE_EH) + { + gimple stmt = last_stmt (e->src); + remove_stmt_from_eh_lp (stmt); remove_edge (e); - } - - /* Verify that we eliminated all uses of PHI we are going to remove. - If we didn't, rebuild SSA on affected variable (this is allowed only - for virtuals). */ - for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si)) - { - gimple phi = gsi_stmt (si); - tree result = gimple_phi_result (phi); - if (!has_zero_uses (result)) - { - use_operand_p use_p; - imm_use_iterator iter; - gimple stmt; + } + else + ei_next (&ei); + goto succeed; + } - FOR_EACH_IMM_USE_STMT (stmt, iter, result) - { - /* We have use, see if it won't disappear after - removing BB. */ - if (gimple_bb (stmt) == bb) - continue; - if (gimple_code (stmt) == GIMPLE_PHI) - { - bool bad = false; - - FOR_EACH_IMM_USE_ON_STMT (use_p, iter) - if (gimple_phi_arg_edge (stmt, - PHI_ARG_INDEX_FROM_USE (use_p))->src != bb) - { - bad = true; - break; - } - - if (!bad) - continue; - } - - gcc_assert (!is_gimple_reg (result)); - mark_sym_for_renaming (SSA_NAME_VAR (result)); - /* As we are going to delete this block we will release all - defs which makes the immediate uses on use stmts invalid. - Avoid that by replacing all uses with the bare variable - and updating the stmts. */ - FOR_EACH_IMM_USE_ON_STMT (use_p, iter) - SET_USE (use_p, SSA_NAME_VAR (result)); - update_stmt (stmt); - } - } - } - if (!ei_safe_edge (ei_start (bb->preds))) - delete_basic_block (bb); + /* If the destination region is a MUST_NOT_THROW, allow the runtime + to handle the abort and allow the blocks to go unreachable. */ + if (new_region->type == ERT_MUST_NOT_THROW) + { + for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); ) + if (e->flags & EDGE_EH) + { + gimple stmt = last_stmt (e->src); + remove_stmt_from_eh_lp (stmt); + add_stmt_to_eh_lp (stmt, new_lp_nr); + remove_edge (e); + } + else + ei_next (&ei); + goto succeed; + } + + /* Try to redirect the EH edges and merge the PHIs into the destination + landing pad block. If the merge succeeds, we'll already have redirected + all the EH edges. The handler itself will go unreachable if there were + no normal edges. */ + if (cleanup_empty_eh_merge_phis (e_out->dest, bb, e_out)) + goto succeed; + + /* Finally, if all input edges are EH edges, then we can (potentially) + reduce the number of transfers from the runtime by moving the landing + pad from the original region to the new region. This is a win when + we remove the last CLEANUP region along a particular exception + propagation path. Since nothing changes except for the region with + which the landing pad is associated, the PHI nodes do not need to be + adjusted at all. */ + if (!has_non_eh_pred) + { + cleanup_empty_eh_move_lp (bb, e_out, lp, new_region); + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "Empty EH handler %i moved to EH region %i.\n", + lp->index, new_region->index); + + /* ??? The CFG didn't change, but we may have rendered the + old EH region unreachable. Trigger a cleanup there. */ return true; } + return false; + + succeed: + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "Empty EH handler %i removed.\n", lp->index); + remove_eh_landing_pad (lp); + return true; } +/* Do a post-order traversal of the EH region tree. Examine each + post_landing_pad block and see if we can eliminate it as empty. */ + +static bool +cleanup_all_empty_eh (void) +{ + bool changed = false; + eh_landing_pad lp; + int i; + + for (i = 1; VEC_iterate (eh_landing_pad, cfun->eh->lp_array, i, lp); ++i) + if (lp) + changed |= cleanup_empty_eh (lp); + + return changed; +} /* Perform cleanups and lowering of exception handling 1) cleanups regions with handlers doing nothing are optimized out @@ -3246,63 +3749,58 @@ cleanup_empty_eh (basic_block bb, VEC(int,heap) * label_to_region) 3) Info about regions that are containing instructions, and regions reachable via local EH edges is collected 4) Eh tree is pruned for regions no longer neccesary. - */ + + TODO: Push MUST_NOT_THROW regions to the root of the EH tree. + Unify those that have the same failure decl and locus. +*/ static unsigned int -cleanup_eh (void) +execute_cleanup_eh (void) { - bool changed = false; - basic_block bb; - VEC(int,heap) * label_to_region; - int i; + /* Do this first: unsplit_all_eh and cleanup_all_empty_eh can die + looking up unreachable landing pads. */ + remove_unreachable_handlers (); - if (!cfun->eh) - return 0; - if (dump_file) + /* Watch out for the region tree vanishing due to all unreachable. */ + if (cfun->eh->region_tree && optimize) { - fprintf (dump_file, "Before cleanups:\n"); - dump_eh_tree (dump_file, cfun); - } + bool changed = false; - if (optimize) - { - label_to_region = label_to_region_map (); - dominance_info_invalidated = false; - /* We cannot use FOR_EACH_BB, since the basic blocks may get removed. */ - for (i = NUM_FIXED_BLOCKS; i < last_basic_block; i++) - { - bb = BASIC_BLOCK (i); - if (bb) - changed |= cleanup_empty_eh (bb, label_to_region); - } - VEC_free (int, heap, label_to_region); - if (dominance_info_invalidated) + changed |= unsplit_all_eh (); + changed |= cleanup_all_empty_eh (); + + if (changed) { free_dominance_info (CDI_DOMINATORS); free_dominance_info (CDI_POST_DOMINATORS); - } - /* Removing contained cleanup can render MUST_NOT_THROW regions empty. */ - if (changed) - delete_unreachable_blocks (); - } + /* We delayed all basic block deletion, as we may have performed + cleanups on EH edges while non-EH edges were still present. */ + delete_unreachable_blocks (); - tree_remove_unreachable_handlers (); - if (dump_file) - { - fprintf (dump_file, "After cleanups:\n"); - dump_eh_tree (dump_file, cfun); + /* We manipulated the landing pads. Remove any region that no + longer has a landing pad. */ + remove_unreachable_handlers_no_lp (); + + return TODO_cleanup_cfg | TODO_update_ssa_only_virtuals; + } } - return (changed ? TODO_cleanup_cfg | TODO_update_ssa : 0); + return 0; +} + +static bool +gate_cleanup_eh (void) +{ + return cfun->eh != NULL && cfun->eh->region_tree != NULL; } struct gimple_opt_pass pass_cleanup_eh = { { GIMPLE_PASS, "ehcleanup", /* name */ - NULL, /* gate */ - cleanup_eh, /* execute */ + gate_cleanup_eh, /* gate */ + execute_cleanup_eh, /* execute */ NULL, /* sub */ NULL, /* next */ 0, /* static_pass_number */ @@ -3314,3 +3812,150 @@ struct gimple_opt_pass pass_cleanup_eh = { TODO_dump_func /* todo_flags_finish */ } }; + +/* Verify that BB containing STMT as the last statement, has precisely the + edge that make_eh_edges would create. */ + +bool +verify_eh_edges (gimple stmt) +{ + basic_block bb = gimple_bb (stmt); + eh_landing_pad lp = NULL; + int lp_nr; + edge_iterator ei; + edge e, eh_edge; + + lp_nr = lookup_stmt_eh_lp (stmt); + if (lp_nr > 0) + lp = get_eh_landing_pad_from_number (lp_nr); + + eh_edge = NULL; + FOR_EACH_EDGE (e, ei, bb->succs) + { + if (e->flags & EDGE_EH) + { + if (eh_edge) + { + error ("BB %i has multiple EH edges", bb->index); + return true; + } + else + eh_edge = e; + } + } + + if (lp == NULL) + { + if (eh_edge) + { + error ("BB %i can not throw but has an EH edge", bb->index); + return true; + } + return false; + } + + if (!stmt_could_throw_p (stmt)) + { + error ("BB %i last statement has incorrectly set lp", bb->index); + return true; + } + + if (eh_edge == NULL) + { + error ("BB %i is missing an EH edge", bb->index); + return true; + } + + if (eh_edge->dest != label_to_block (lp->post_landing_pad)) + { + error ("Incorrect EH edge %i->%i", bb->index, eh_edge->dest->index); + return true; + } + + return false; +} + +/* Similarly, but handle GIMPLE_EH_DISPATCH specifically. */ + +bool +verify_eh_dispatch_edge (gimple stmt) +{ + eh_region r; + eh_catch c; + basic_block src, dst; + bool want_fallthru = true; + edge_iterator ei; + edge e, fall_edge; + + r = get_eh_region_from_number (gimple_eh_dispatch_region (stmt)); + src = gimple_bb (stmt); + + FOR_EACH_EDGE (e, ei, src->succs) + gcc_assert (e->aux == NULL); + + switch (r->type) + { + case ERT_TRY: + for (c = r->u.eh_try.first_catch; c ; c = c->next_catch) + { + dst = label_to_block (c->label); + e = find_edge (src, dst); + if (e == NULL) + { + error ("BB %i is missing an edge", src->index); + return true; + } + e->aux = (void *)e; + + /* A catch-all handler doesn't have a fallthru. */ + if (c->type_list == NULL) + { + want_fallthru = false; + break; + } + } + break; + + case ERT_ALLOWED_EXCEPTIONS: + dst = label_to_block (r->u.allowed.label); + e = find_edge (src, dst); + if (e == NULL) + { + error ("BB %i is missing an edge", src->index); + return true; + } + e->aux = (void *)e; + break; + + default: + gcc_unreachable (); + } + + fall_edge = NULL; + FOR_EACH_EDGE (e, ei, src->succs) + { + if (e->flags & EDGE_FALLTHRU) + { + if (fall_edge != NULL) + { + error ("BB %i too many fallthru edges", src->index); + return true; + } + fall_edge = e; + } + else if (e->aux) + e->aux = NULL; + else + { + error ("BB %i has incorrect edge", src->index); + return true; + } + } + if ((fall_edge != NULL) ^ want_fallthru) + { + error ("BB %i has incorrect fallthru edge", src->index); + return true; + } + + return false; +} |