/* Exception handling semantics and decomposition for trees.
- Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009
+ Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
Free Software Foundation, Inc.
This file is part of GCC.
#include "coretypes.h"
#include "tm.h"
#include "tree.h"
-#include "rtl.h"
-#include "tm_p.h"
#include "flags.h"
#include "function.h"
#include "except.h"
+#include "pointer-set.h"
#include "tree-flow.h"
#include "tree-dump.h"
#include "tree-inline.h"
if (tf->goto_queue_active == 0)
return;
replace_goto_queue_stmt_list (tf->top_p_seq, tf);
+ replace_goto_queue_stmt_list (eh_seq, tf);
}
/* Add a new record to the goto queue contained in TF. NEW_STMT is the
labels. */
new_stmt = stmt;
record_in_goto_queue (tf, new_stmt, index, true);
-
}
/* For any GIMPLE_GOTO or GIMPLE_RETURN, decide whether it leaves a try_finally
return f_estimate < 40 || f_estimate * 2 < sw_estimate * 3;
}
+/* REG is the enclosing region for a possible cleanup region, or the region
+ itself. Returns TRUE if such a region would be unreachable.
+
+ Cleanup regions within a must-not-throw region aren't actually reachable
+ even if there are throwing stmts within them, because the personality
+ routine will call terminate before unwinding. */
+
+static bool
+cleanup_is_dead_in (eh_region reg)
+{
+ while (reg && reg->type == ERT_CLEANUP)
+ reg = reg->outer;
+ return (reg && reg->type == ERT_MUST_NOT_THROW);
+}
/* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_FINALLY nodes
to a sequence of labels and blocks, plus the exception region trees
struct leh_tf_state this_tf;
struct leh_state this_state;
int ndests;
+ gimple_seq old_eh_seq;
/* Process the try block. */
this_tf.try_finally_expr = 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);
+ if (using_eh_for_cleanups_p && !cleanup_is_dead_in (state->cur_region))
+ {
+ this_tf.region = gen_eh_region_cleanup (state->cur_region);
+ this_state.cur_region = this_tf.region;
+ }
else
- this_tf.region = NULL;
+ {
+ this_tf.region = NULL;
+ this_state.cur_region = state->cur_region;
+ }
- this_state.cur_region = this_tf.region;
this_state.ehp_region = state->ehp_region;
this_state.tf = &this_tf;
+ old_eh_seq = eh_seq;
+ eh_seq = NULL;
+
lower_eh_constructs_1 (&this_state, gimple_try_eval(tp));
/* Determine if the try block is escaped through the bottom. */
this_tf.may_fallthru = gimple_seq_may_fallthru (gimple_try_eval (tp));
/* Determine if any exceptions are possible within the try block. */
- if (using_eh_for_cleanups_p)
+ if (this_tf.region)
this_tf.may_throw = eh_region_may_contain_throw (this_tf.region);
if (this_tf.may_throw)
honor_protect_cleanup_actions (state, &this_state, &this_tf);
if (this_tf.goto_queue_map)
pointer_map_destroy (this_tf.goto_queue_map);
+ /* If there was an old (aka outer) eh_seq, append the current eh_seq.
+ If there was no old eh_seq, then the append is trivially already done. */
+ if (old_eh_seq)
+ {
+ if (eh_seq == NULL)
+ eh_seq = old_eh_seq;
+ else
+ {
+ gimple_seq new_eh_seq = eh_seq;
+ eh_seq = old_eh_seq;
+ gimple_seq_add_seq(&eh_seq, new_eh_seq);
+ }
+ }
+
return this_tf.top_p_seq;
}
x = gimple_build_goto (out_label);
gimple_seq_add_stmt (&new_seq, x);
}
+ if (!c->type_list)
+ break;
}
gimple_try_set_cleanup (tp, new_seq);
eh_region this_region = NULL;
struct leh_tf_state fake_tf;
gimple_seq result;
+ bool cleanup_dead = cleanup_is_dead_in (state->cur_region);
- if (flag_exceptions)
+ if (flag_exceptions && !cleanup_dead)
{
this_region = gen_eh_region_cleanup (state->cur_region);
this_state.cur_region = this_region;
lower_eh_constructs_1 (&this_state, gimple_try_eval (tp));
- if (!eh_region_may_contain_throw (this_region))
+ if (cleanup_dead || !eh_region_may_contain_throw (this_region))
return gimple_try_eval (tp);
/* Build enough of a try-finally state so that we can reuse
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
- available on the EH edge. */
+ available on the EH edge. Only do so for statements that
+ potentially fall thru (no noreturn calls e.g.), otherwise
+ this new assignment might create fake fallthru regions. */
if (stmt_could_throw_p (stmt)
&& gimple_has_lhs (stmt)
+ && gimple_stmt_may_fallthru (stmt)
&& !tree_could_throw_p (gimple_get_lhs (stmt))
&& is_gimple_reg_type (TREE_TYPE (gimple_get_lhs (stmt))))
{
};
-/* At the end of inlining, we can lower EH_DISPATCH. */
+/* At the end of inlining, we can lower EH_DISPATCH. Return true when
+ we have found some duplicate labels and removed some edges. */
-static void
+static bool
lower_eh_dispatch (basic_block src, gimple stmt)
{
gimple_stmt_iterator gsi;
eh_region r;
tree filter, fn;
gimple x;
+ bool redirected = false;
region_nr = gimple_eh_dispatch_region (stmt);
r = get_eh_region_from_number (region_nr);
eh_catch c;
edge_iterator ei;
edge e;
+ struct pointer_set_t *seen_values = pointer_set_create ();
/* Collect the labels for a switch. Zero the post_landing_pad
field becase we'll no longer have anything keeping these labels
for (c = r->u.eh_try.first_catch; c ; c = c->next_catch)
{
tree tp_node, flt_node, lab = c->label;
+ bool have_label = false;
c->label = NULL;
tp_node = c->type_list;
}
do
{
- tree t = build3 (CASE_LABEL_EXPR, void_type_node,
- TREE_VALUE (flt_node), NULL, lab);
- VEC_safe_push (tree, heap, labels, t);
+ /* Filter out duplicate labels that arise when this handler
+ is shadowed by an earlier one. When no labels are
+ attached to the handler anymore, we remove
+ the corresponding edge and then we delete unreachable
+ blocks at the end of this pass. */
+ if (! pointer_set_contains (seen_values, TREE_VALUE (flt_node)))
+ {
+ tree t = build3 (CASE_LABEL_EXPR, void_type_node,
+ TREE_VALUE (flt_node), NULL, lab);
+ VEC_safe_push (tree, heap, labels, t);
+ pointer_set_insert (seen_values, TREE_VALUE (flt_node));
+ have_label = true;
+ }
tp_node = TREE_CHAIN (tp_node);
flt_node = TREE_CHAIN (flt_node);
}
while (tp_node);
+ if (! have_label)
+ {
+ remove_edge (find_edge (src, label_to_block (lab)));
+ redirected = true;
+ }
}
/* Clean up the edge flags. */
VEC_free (tree, heap, labels);
}
+ pointer_set_destroy (seen_values);
}
break;
/* Replace the EH_DISPATCH with the SWITCH or COND generated above. */
gsi_remove (&gsi, true);
+ return redirected;
}
static unsigned
{
basic_block bb;
bool any_rewritten = false;
+ bool redirected = false;
assign_filter_values ();
gimple last = last_stmt (bb);
if (last && gimple_code (last) == GIMPLE_EH_DISPATCH)
{
- lower_eh_dispatch (bb, last);
+ redirected |= lower_eh_dispatch (bb, last);
any_rewritten = true;
}
}
+ if (redirected)
+ delete_unreachable_blocks ();
return any_rewritten ? TODO_update_ssa_only_virtuals : 0;
}
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)))
+ /* The block must be empty except for the labels and debug insns. */
+ gsi = gsi_after_labels (bb);
+ if (!gsi_end_p (gsi) && is_gimple_debug (gsi_stmt (gsi)))
+ gsi_next_nondebug (&gsi);
+ if (!gsi_end_p (gsi))
return false;
/* The destination block must not already have a landing pad
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