--- /dev/null
+/* Exception handling semantics and decomposition for trees.
+ Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009
+ Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3, or (at your option)
+any later version.
+
+GCC is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
+
+#include "config.h"
+#include "system.h"
+#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 "tree-flow.h"
+#include "tree-dump.h"
+#include "tree-inline.h"
+#include "tree-iterator.h"
+#include "tree-pass.h"
+#include "timevar.h"
+#include "langhooks.h"
+#include "ggc.h"
+#include "toplev.h"
+#include "gimple.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. */
+typedef union {tree *tp; tree t; gimple g;} treemple;
+
+/* Nonzero if we are using EH to handle cleanups. */
+static int using_eh_for_cleanups_p = 0;
+
+void
+using_eh_for_cleanups (void)
+{
+ using_eh_for_cleanups_p = 1;
+}
+
+/* Misc functions used in this file. */
+
+/* Compare and hash for any structure which begins with a canonical
+ pointer. Assumes all pointers are interchangeable, which is sort
+ of already assumed by gcc elsewhere IIRC. */
+
+static int
+struct_ptr_eq (const void *a, const void *b)
+{
+ const void * const * x = (const void * const *) a;
+ const void * const * y = (const void * const *) b;
+ return *x == *y;
+}
+
+static hashval_t
+struct_ptr_hash (const void *a)
+{
+ const void * const * x = (const void * const *) a;
+ return (size_t)*x >> 4;
+}
+
+
+/* Remember and lookup EH region 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:
+
+ (1) We absolutely rely on this information being kept until
+ we get to rtl. Once we're done with lowering here, if we lose
+ the information there's no way to recover it!
+
+ (2) There are many more statements that *cannot* throw as
+ 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 *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. */
+
+void
+add_stmt_to_eh_region_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);
+
+ n = GGC_NEW (struct throw_stmt_node);
+ n->stmt = t;
+ n->region_nr = num;
+
+ if (!get_eh_throw_stmt_table (ifun))
+ set_eh_throw_stmt_table (ifun, htab_create_ggc (31, struct_ptr_hash,
+ struct_ptr_eq,
+ ggc_free));
+
+ slot = htab_find_slot (get_eh_throw_stmt_table (ifun), n, INSERT);
+ gcc_assert (!*slot);
+ *slot = n;
+}
+
+
+/* Add statement T in the current function (cfun) to EH region number
+ NUM. */
+
+void
+add_stmt_to_eh_region (gimple t, int num)
+{
+ add_stmt_to_eh_region_fn (cfun, t, num);
+}
+
+
+/* Remove statement T in function IFUN from the EH region holding it. */
+
+bool
+remove_stmt_from_eh_region_fn (struct function *ifun, gimple t)
+{
+ struct throw_stmt_node dummy;
+ void **slot;
+
+ if (!get_eh_throw_stmt_table (ifun))
+ return false;
+
+ dummy.stmt = t;
+ slot = htab_find_slot (get_eh_throw_stmt_table (ifun), &dummy,
+ NO_INSERT);
+ if (slot)
+ {
+ htab_clear_slot (get_eh_throw_stmt_table (ifun), slot);
+ return true;
+ }
+ else
+ return false;
+}
+
+
+/* Remove statement T in the current function (cfun) from the EH
+ region holding it. */
+
+bool
+remove_stmt_from_eh_region (gimple t)
+{
+ return remove_stmt_from_eh_region_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. */
+
+int
+lookup_stmt_eh_region_fn (struct function *ifun, gimple t)
+{
+ struct throw_stmt_node *p, n;
+
+ if (!get_eh_throw_stmt_table (ifun))
+ return -2;
+
+ n.stmt = t;
+ p = (struct throw_stmt_node *) htab_find (get_eh_throw_stmt_table (ifun), &n);
+ return (p ? p->region_nr : -1);
+}
+
+
+/* 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. */
+
+int
+lookup_stmt_eh_region (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);
+}
+
+
+/* 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. */
+
+int
+lookup_expr_eh_region (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))
+ {
+ tree_ann_common_t ann = tree_common_ann (t);
+ if (ann)
+ return (int) ann->rn;
+ }
+
+ return -1;
+}
+
+
+/* First pass of EH node decomposition. Build up a tree of GIMPLE_TRY_FINALLY
+ nodes and LABEL_DECL nodes. We will use this during the second phase to
+ determine if a goto leaves the body of a TRY_FINALLY_EXPR node. */
+
+struct finally_tree_node
+{
+ /* When storing a GIMPLE_TRY, we have to record a gimple. However
+ 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;
+ gimple parent;
+};
+
+/* Note that this table is *not* marked GTY. It is short-lived. */
+static htab_t finally_tree;
+
+static void
+record_in_finally_tree (treemple child, gimple parent)
+{
+ struct finally_tree_node *n;
+ void **slot;
+
+ n = XNEW (struct finally_tree_node);
+ n->child = child;
+ n->parent = parent;
+
+ slot = htab_find_slot (finally_tree, n, INSERT);
+ gcc_assert (!*slot);
+ *slot = n;
+}
+
+static void
+collect_finally_tree (gimple stmt, gimple region);
+
+/* Go through the gimple sequence. Works with collect_finally_tree to
+ record all GIMPLE_LABEL and GIMPLE_TRY statements. */
+
+static void
+collect_finally_tree_1 (gimple_seq seq, gimple region)
+{
+ gimple_stmt_iterator gsi;
+
+ for (gsi = gsi_start (seq); !gsi_end_p (gsi); gsi_next (&gsi))
+ collect_finally_tree (gsi_stmt (gsi), region);
+}
+
+static void
+collect_finally_tree (gimple stmt, gimple region)
+{
+ treemple temp;
+
+ switch (gimple_code (stmt))
+ {
+ case GIMPLE_LABEL:
+ temp.t = gimple_label_label (stmt);
+ record_in_finally_tree (temp, region);
+ break;
+
+ case GIMPLE_TRY:
+ if (gimple_try_kind (stmt) == GIMPLE_TRY_FINALLY)
+ {
+ temp.g = stmt;
+ record_in_finally_tree (temp, region);
+ collect_finally_tree_1 (gimple_try_eval (stmt), stmt);
+ collect_finally_tree_1 (gimple_try_cleanup (stmt), region);
+ }
+ else if (gimple_try_kind (stmt) == GIMPLE_TRY_CATCH)
+ {
+ collect_finally_tree_1 (gimple_try_eval (stmt), region);
+ collect_finally_tree_1 (gimple_try_cleanup (stmt), region);
+ }
+ break;
+
+ case GIMPLE_CATCH:
+ collect_finally_tree_1 (gimple_catch_handler (stmt), region);
+ break;
+
+ case GIMPLE_EH_FILTER:
+ collect_finally_tree_1 (gimple_eh_filter_failure (stmt), region);
+ break;
+
+ default:
+ /* A type, a decl, or some kind of statement that we're not
+ interested in. Don't walk them. */
+ break;
+ }
+}
+
+
+/* Use the finally tree to determine if a jump from START to TARGET
+ would leave the try_finally node that START lives in. */
+
+static bool
+outside_finally_tree (treemple start, gimple target)
+{
+ struct finally_tree_node n, *p;
+
+ do
+ {
+ n.child = start;
+ p = (struct finally_tree_node *) htab_find (finally_tree, &n);
+ if (!p)
+ return true;
+ start.g = p->parent;
+ }
+ while (start.g != target);
+
+ return false;
+}
+
+/* Second pass of EH node decomposition. Actually transform the GIMPLE_TRY
+ nodes into a set of gotos, magic labels, and eh regions.
+ The eh region creation is straight-forward, but frobbing all the gotos
+ and such into shape isn't. */
+
+/* State of the world while lowering. */
+
+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 *cur_region;
+ struct eh_region *prev_try;
+
+ /* Processing of TRY_FINALLY requires a bit more state. This is
+ split out into a separate structure so that we don't have to
+ copy so much when processing other nodes. */
+ struct leh_tf_state *tf;
+};
+
+struct leh_tf_state
+{
+ /* Pointer to the GIMPLE_TRY_FINALLY node under discussion. The
+ try_finally_expr is the original GIMPLE_TRY_FINALLY. We need to retain
+ this so that outside_finally_tree can reliably reference the tree used
+ 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;
+
+ /* The state outside this try_finally node. */
+ struct leh_state *outer;
+
+ /* The exception region created for it. */
+ struct eh_region *region;
+
+ /* 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
+ the conditionals, which get their labels recorded. Since labels are of
+ type 'tree', we need this node to store both gimple and tree objects.
+ REPL_STMT is the sequence used to replace the goto/return statement.
+ CONT_STMT is used to store the statement that allows the return/goto to
+ jump to the original destination. */
+ struct goto_queue_node {
+ treemple stmt;
+ gimple_seq repl_stmt;
+ gimple cont_stmt;
+ int index;
+ /* this is used when index >= 0 to indicate that stmt is a label(as
+ opposed to a goto stmt) */
+ int is_label;
+ } *goto_queue;
+ size_t goto_queue_size;
+ size_t goto_queue_active;
+
+ /* Pointer map to help in searching goto_queue when it is large. */
+ struct pointer_map_t *goto_queue_map;
+
+ /* The set of unique labels seen as entries in the goto queue. */
+ VEC(tree,heap) *dest_array;
+
+ /* A label to be added at the end of the completed transformed
+ sequence. It will be set if may_fallthru was true *at one time*,
+ 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;
+
+ /* True if any entry in goto_queue is a GIMPLE_RETURN. */
+ bool may_return;
+
+ /* True if the finally block can receive an exception edge.
+ Cleared if the exception case is handled by code duplication. */
+ bool may_throw;
+};
+
+static gimple_seq lower_eh_filter (struct leh_state *, gimple);
+
+/* Search for STMT in the goto queue. Return the replacement,
+ or null if the statement isn't in the queue. */
+
+#define LARGE_GOTO_QUEUE 20
+
+static void lower_eh_constructs_1 (struct leh_state *state, gimple_seq seq);
+
+static gimple_seq
+find_goto_replacement (struct leh_tf_state *tf, treemple stmt)
+{
+ unsigned int i;
+ void **slot;
+
+ if (tf->goto_queue_active < LARGE_GOTO_QUEUE)
+ {
+ for (i = 0; i < tf->goto_queue_active; i++)
+ if ( tf->goto_queue[i].stmt.g == stmt.g)
+ return tf->goto_queue[i].repl_stmt;
+ return NULL;
+ }
+
+ /* If we have a large number of entries in the goto_queue, create a
+ pointer map and use that for searching. */
+
+ if (!tf->goto_queue_map)
+ {
+ tf->goto_queue_map = pointer_map_create ();
+ for (i = 0; i < tf->goto_queue_active; i++)
+ {
+ slot = pointer_map_insert (tf->goto_queue_map,
+ tf->goto_queue[i].stmt.g);
+ gcc_assert (*slot == NULL);
+ *slot = &tf->goto_queue[i];
+ }
+ }
+
+ slot = pointer_map_contains (tf->goto_queue_map, stmt.g);
+ if (slot != NULL)
+ return (((struct goto_queue_node *) *slot)->repl_stmt);
+
+ return NULL;
+}
+
+/* A subroutine of replace_goto_queue_1. Handles the sub-clauses of a
+ lowered GIMPLE_COND. If, by chance, the replacement is a simple goto,
+ then we can just splat it in, otherwise we add the new stmts immediately
+ after the GIMPLE_COND and redirect. */
+
+static void
+replace_goto_queue_cond_clause (tree *tp, struct leh_tf_state *tf,
+ gimple_stmt_iterator *gsi)
+{
+ tree label;
+ gimple_seq new_seq;
+ treemple temp;
+
+ temp.tp = tp;
+ new_seq = find_goto_replacement (tf, temp);
+ if (!new_seq)
+ return;
+
+ if (gimple_seq_singleton_p (new_seq)
+ && gimple_code (gimple_seq_first_stmt (new_seq)) == GIMPLE_GOTO)
+ {
+ *tp = gimple_goto_dest (gimple_seq_first_stmt (new_seq));
+ return;
+ }
+
+ label = create_artificial_label ();
+ /* Set the new label for the GIMPLE_COND */
+ *tp = label;
+
+ gsi_insert_after (gsi, gimple_build_label (label), GSI_CONTINUE_LINKING);
+ gsi_insert_seq_after (gsi, gimple_seq_copy (new_seq), GSI_CONTINUE_LINKING);
+}
+
+/* The real work of replace_goto_queue. Returns with TSI updated to
+ point to the next statement. */
+
+static void replace_goto_queue_stmt_list (gimple_seq, struct leh_tf_state *);
+
+static void
+replace_goto_queue_1 (gimple stmt, struct leh_tf_state *tf,
+ gimple_stmt_iterator *gsi)
+{
+ gimple_seq seq;
+ treemple temp;
+ temp.g = NULL;
+
+ switch (gimple_code (stmt))
+ {
+ case GIMPLE_GOTO:
+ case GIMPLE_RETURN:
+ temp.g = stmt;
+ seq = find_goto_replacement (tf, temp);
+ if (seq)
+ {
+ gsi_insert_seq_before (gsi, gimple_seq_copy (seq), GSI_SAME_STMT);
+ gsi_remove (gsi, false);
+ return;
+ }
+ break;
+
+ case GIMPLE_COND:
+ replace_goto_queue_cond_clause (gimple_op_ptr (stmt, 2), tf, gsi);
+ replace_goto_queue_cond_clause (gimple_op_ptr (stmt, 3), tf, gsi);
+ break;
+
+ case GIMPLE_TRY:
+ replace_goto_queue_stmt_list (gimple_try_eval (stmt), tf);
+ replace_goto_queue_stmt_list (gimple_try_cleanup (stmt), tf);
+ break;
+ case GIMPLE_CATCH:
+ replace_goto_queue_stmt_list (gimple_catch_handler (stmt), tf);
+ break;
+ case GIMPLE_EH_FILTER:
+ replace_goto_queue_stmt_list (gimple_eh_filter_failure (stmt), tf);
+ break;
+
+ default:
+ /* These won't have gotos in them. */
+ break;
+ }
+
+ gsi_next (gsi);
+}
+
+/* A subroutine of replace_goto_queue. Handles GIMPLE_SEQ. */
+
+static void
+replace_goto_queue_stmt_list (gimple_seq seq, struct leh_tf_state *tf)
+{
+ gimple_stmt_iterator gsi = gsi_start (seq);
+
+ while (!gsi_end_p (gsi))
+ replace_goto_queue_1 (gsi_stmt (gsi), tf, &gsi);
+}
+
+/* Replace all goto queue members. */
+
+static void
+replace_goto_queue (struct leh_tf_state *tf)
+{
+ if (tf->goto_queue_active == 0)
+ return;
+ replace_goto_queue_stmt_list (tf->top_p_seq, tf);
+}
+
+/* Add a new record to the goto queue contained in TF. NEW_STMT is the
+ data to be added, IS_LABEL indicates whether NEW_STMT is a label or
+ a gimple return. */
+
+static void
+record_in_goto_queue (struct leh_tf_state *tf,
+ treemple new_stmt,
+ int index,
+ bool is_label)
+{
+ size_t active, size;
+ struct goto_queue_node *q;
+
+ gcc_assert (!tf->goto_queue_map);
+
+ active = tf->goto_queue_active;
+ size = tf->goto_queue_size;
+ if (active >= size)
+ {
+ size = (size ? size * 2 : 32);
+ tf->goto_queue_size = size;
+ tf->goto_queue
+ = XRESIZEVEC (struct goto_queue_node, tf->goto_queue, size);
+ }
+
+ q = &tf->goto_queue[active];
+ tf->goto_queue_active = active + 1;
+
+ memset (q, 0, sizeof (*q));
+ q->stmt = new_stmt;
+ q->index = index;
+ q->is_label = is_label;
+}
+
+/* Record the LABEL label in the goto queue contained in TF.
+ TF is not null. */
+
+static void
+record_in_goto_queue_label (struct leh_tf_state *tf, treemple stmt, tree label)
+{
+ int index;
+ treemple temp, new_stmt;
+
+ if (!label)
+ return;
+
+ /* Computed and non-local gotos do not get processed. Given
+ their nature we can neither tell whether we've escaped the
+ finally block nor redirect them if we knew. */
+ if (TREE_CODE (label) != LABEL_DECL)
+ return;
+
+ /* No need to record gotos that don't leave the try block. */
+ temp.t = label;
+ if (!outside_finally_tree (temp, tf->try_finally_expr))
+ return;
+
+ if (! tf->dest_array)
+ {
+ tf->dest_array = VEC_alloc (tree, heap, 10);
+ VEC_quick_push (tree, tf->dest_array, label);
+ index = 0;
+ }
+ else
+ {
+ int n = VEC_length (tree, tf->dest_array);
+ for (index = 0; index < n; ++index)
+ if (VEC_index (tree, tf->dest_array, index) == label)
+ break;
+ if (index == n)
+ VEC_safe_push (tree, heap, tf->dest_array, label);
+ }
+
+ /* In the case of a GOTO we want to record the destination label,
+ since with a GIMPLE_COND we have an easy access to the then/else
+ 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
+ node, and if so record that fact in the goto queue associated with that
+ try_finally node. */
+
+static void
+maybe_record_in_goto_queue (struct leh_state *state, gimple stmt)
+{
+ struct leh_tf_state *tf = state->tf;
+ treemple new_stmt;
+
+ if (!tf)
+ return;
+
+ switch (gimple_code (stmt))
+ {
+ case GIMPLE_COND:
+ new_stmt.tp = gimple_op_ptr (stmt, 2);
+ record_in_goto_queue_label (tf, new_stmt, gimple_cond_true_label (stmt));
+ new_stmt.tp = gimple_op_ptr (stmt, 3);
+ record_in_goto_queue_label (tf, new_stmt, gimple_cond_false_label (stmt));
+ break;
+ case GIMPLE_GOTO:
+ new_stmt.g = stmt;
+ record_in_goto_queue_label (tf, new_stmt, gimple_goto_dest (stmt));
+ break;
+
+ case GIMPLE_RETURN:
+ tf->may_return = true;
+ new_stmt.g = stmt;
+ record_in_goto_queue (tf, new_stmt, -1, false);
+ break;
+
+ default:
+ gcc_unreachable ();
+ }
+}
+
+
+#ifdef ENABLE_CHECKING
+/* We do not process GIMPLE_SWITCHes for now. As long as the original source
+ was in fact structured, and we've not yet done jump threading, then none
+ of the labels will leave outer GIMPLE_TRY_FINALLY nodes. Verify this. */
+
+static void
+verify_norecord_switch_expr (struct leh_state *state, gimple switch_expr)
+{
+ struct leh_tf_state *tf = state->tf;
+ size_t i, n;
+
+ if (!tf)
+ return;
+
+ n = gimple_switch_num_labels (switch_expr);
+
+ for (i = 0; i < n; ++i)
+ {
+ treemple temp;
+ tree lab = CASE_LABEL (gimple_switch_label (switch_expr, i));
+ temp.t = lab;
+ gcc_assert (!outside_finally_tree (temp, tf->try_finally_expr));
+ }
+}
+#else
+#define verify_norecord_switch_expr(state, switch_expr)
+#endif
+
+/* Redirect a RETURN_EXPR pointed to by STMT_P to FINLAB. Place in CONT_P
+ whatever is needed to finish the return. If MOD is non-null, insert it
+ before the new branch. RETURN_VALUE_P is a cache containing a temporary
+ variable to be used in manipulating the value returned from the function. */
+
+static void
+do_return_redirection (struct goto_queue_node *q, tree finlab, gimple_seq mod,
+ tree *return_value_p)
+{
+ tree ret_expr;
+ gimple x;
+
+ /* In the case of a return, the queue node must be a gimple statement. */
+ gcc_assert (!q->is_label);
+
+ ret_expr = gimple_return_retval (q->stmt.g);
+
+ if (ret_expr)
+ {
+ if (!*return_value_p)
+ *return_value_p = ret_expr;
+ else
+ gcc_assert (*return_value_p == ret_expr);
+ q->cont_stmt = q->stmt.g;
+ /* The nasty part about redirecting the return value is that the
+ return value itself is to be computed before the FINALLY block
+ is executed. e.g.
+
+ int x;
+ int foo (void)
+ {
+ x = 0;
+ try {
+ return x;
+ } finally {
+ x++;
+ }
+ }
+
+ should return 0, not 1. Arrange for this to happen by copying
+ computed the return value into a local temporary. This also
+ allows us to redirect multiple return statements through the
+ same destination block; whether this is a net win or not really
+ depends, I guess, but it does make generation of the switch in
+ lower_try_finally_switch easier. */
+
+ if (TREE_CODE (ret_expr) == RESULT_DECL)
+ {
+ if (!*return_value_p)
+ *return_value_p = ret_expr;
+ else
+ gcc_assert (*return_value_p == ret_expr);
+ q->cont_stmt = q->stmt.g;
+ }
+ else
+ gcc_unreachable ();
+ }
+ else
+ /* If we don't return a value, all return statements are the same. */
+ q->cont_stmt = q->stmt.g;
+
+ if (!q->repl_stmt)
+ q->repl_stmt = gimple_seq_alloc ();
+
+ if (mod)
+ gimple_seq_add_seq (&q->repl_stmt, mod);
+
+ x = gimple_build_goto (finlab);
+ gimple_seq_add_stmt (&q->repl_stmt, x);
+}
+
+/* Similar, but easier, for GIMPLE_GOTO. */
+
+static void
+do_goto_redirection (struct goto_queue_node *q, tree finlab, gimple_seq mod,
+ struct leh_tf_state *tf)
+{
+ gimple x;
+
+ gcc_assert (q->is_label);
+ if (!q->repl_stmt)
+ q->repl_stmt = gimple_seq_alloc ();
+
+ q->cont_stmt = gimple_build_goto (VEC_index (tree, tf->dest_array,q->index));
+
+ if (mod)
+ gimple_seq_add_seq (&q->repl_stmt, mod);
+
+ x = gimple_build_goto (finlab);
+ gimple_seq_add_stmt (&q->repl_stmt, x);
+}
+
+/* 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
+ 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)
+{
+ gimple x;
+ gimple_seq cleanup, result;
+
+ cleanup = gimple_try_cleanup (tp);
+ result = gimple_try_eval (tp);
+
+ if (gimple_seq_may_fallthru (result))
+ {
+ if (!over)
+ over = create_artificial_label ();
+ x = gimple_build_goto (over);
+ gimple_seq_add_stmt (&result, x);
+ }
+
+ if (lab)
+ {
+ x = gimple_build_label (lab);
+ gimple_seq_add_stmt (&result, x);
+ }
+
+ gimple_seq_add_seq (&result, cleanup);
+
+ if (over)
+ {
+ x = gimple_build_label (over);
+ gimple_seq_add_stmt (&result, x);
+ }
+ return result;
+}
+
+/* A subroutine of lower_try_finally. Duplicate the tree rooted at T.
+ Make sure to record all new labels found. */
+
+static gimple_seq
+lower_try_finally_dup_block (gimple_seq seq, struct leh_state *outer_state)
+{
+ gimple region = NULL;
+ gimple_seq new_seq;
+
+ new_seq = copy_gimple_seq_and_replace_locals (seq);
+
+ if (outer_state->tf)
+ region = outer_state->tf->try_finally_expr;
+ collect_finally_tree_1 (new_seq, region);
+
+ return new_seq;
+}
+
+/* A subroutine of lower_try_finally. Create a fallthru label for
+ the given try_finally state. The only tricky bit here is that
+ we have to make sure to record the label in our outer context. */
+
+static tree
+lower_try_finally_fallthru_label (struct leh_tf_state *tf)
+{
+ tree label = tf->fallthru_label;
+ treemple temp;
+
+ if (!label)
+ {
+ label = create_artificial_label ();
+ tf->fallthru_label = label;
+ if (tf->outer->tf)
+ {
+ temp.t = label;
+ record_in_finally_tree (temp, tf->outer->tf->try_finally_expr);
+ }
+ }
+ return label;
+}
+
+/* A subroutine of lower_try_finally. If lang_protect_cleanup_actions
+ returns non-null, then the language requires that the exception path out
+ of a try_finally be treated specially. To wit: the code within the
+ finally block may not itself throw an exception. We have two choices here.
+ First we can duplicate the finally block and wrap it in a must_not_throw
+ region. Second, we can generate code like
+
+ try {
+ finally_block;
+ } catch {
+ if (fintmp == eh_edge)
+ protect_cleanup_actions;
+ }
+
+ where "fintmp" is the temporary used in the switch statement generation
+ alternative considered below. For the nonce, we always choose the first
+ option.
+
+ THIS_STATE may be null if this is a try-cleanup, not a try-finally. */
+
+static void
+honor_protect_cleanup_actions (struct leh_state *outer_state,
+ struct leh_state *this_state,
+ struct leh_tf_state *tf)
+{
+ gimple 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;
+
+ 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. */
+ if (this_state)
+ finally = lower_try_finally_dup_block (finally, outer_state);
+
+ /* If this cleanup consists of a TRY_CATCH_EXPR with TRY_CATCH_IS_CLEANUP
+ set, the handler of the TRY_CATCH_EXPR is another cleanup which ought
+ to be in an enclosing scope, but needs to be implemented at this level
+ to avoid a nesting violation (see wrap_temporary_cleanups in
+ cp/decl.c). Since it's logically at an outer level, we should call
+ terminate before we get to it, so strip it away before adding the
+ MUST_NOT_THROW filter. */
+ gsi = gsi_start (finally);
+ x = gsi_stmt (gsi);
+ if (protect_cleanup_actions
+ && gimple_code (x) == GIMPLE_TRY
+ && gimple_try_kind (x) == GIMPLE_TRY_CATCH
+ && gimple_try_catch_is_cleanup (x))
+ {
+ gsi_insert_seq_before (&gsi, gimple_try_eval (x), GSI_SAME_STMT);
+ 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);
+
+ /* Having now been handled, EH isn't to be considered with
+ the rest of the outgoing edges. */
+ tf->may_throw = false;
+}
+
+/* A subroutine of lower_try_finally. We have determined that there is
+ no fallthru edge out of the finally block. This means that there is
+ no outgoing edge corresponding to any incoming edge. Restructure the
+ try_finally node for this special case. */
+
+static void
+lower_try_finally_nofallthru (struct leh_state *state,
+ struct leh_tf_state *tf)
+{
+ tree lab, return_val;
+ gimple x;
+ gimple_seq finally;
+ struct goto_queue_node *q, *qe;
+
+ if (tf->may_throw)
+ lab = tf->eh_label;
+ else
+ lab = create_artificial_label ();
+
+ /* We expect that tf->top_p is a GIMPLE_TRY. */
+ finally = gimple_try_cleanup (tf->top_p);
+ tf->top_p_seq = gimple_try_eval (tf->top_p);
+
+ x = gimple_build_label (lab);
+ gimple_seq_add_stmt (&tf->top_p_seq, x);
+
+ return_val = NULL;
+ q = tf->goto_queue;
+ qe = q + tf->goto_queue_active;
+ for (; q < qe; ++q)
+ if (q->index < 0)
+ do_return_redirection (q, lab, NULL, &return_val);
+ else
+ do_goto_redirection (q, lab, NULL, tf);
+
+ replace_goto_queue (tf);
+
+ lower_eh_constructs_1 (state, finally);
+ gimple_seq_add_seq (&tf->top_p_seq, finally);
+}
+
+/* A subroutine of lower_try_finally. We have determined that there is
+ exactly one destination of the finally block. Restructure the
+ try_finally node for this special case. */
+
+static void
+lower_try_finally_onedest (struct leh_state *state, struct leh_tf_state *tf)
+{
+ struct goto_queue_node *q, *qe;
+ gimple x;
+ gimple_seq finally;
+ tree finally_label;
+
+ finally = gimple_try_cleanup (tf->top_p);
+ tf->top_p_seq = gimple_try_eval (tf->top_p);
+
+ lower_eh_constructs_1 (state, finally);
+
+ if (tf->may_throw)
+ {
+ /* 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);
+
+ return;
+ }
+
+ if (tf->may_fallthru)
+ {
+ /* Only reachable via the fallthru edge. Do nothing but let
+ the two blocks run together; we'll fall out the bottom. */
+ gimple_seq_add_seq (&tf->top_p_seq, finally);
+ return;
+ }
+
+ finally_label = create_artificial_label ();
+ x = gimple_build_label (finally_label);
+ gimple_seq_add_stmt (&tf->top_p_seq, x);
+
+ gimple_seq_add_seq (&tf->top_p_seq, finally);
+
+ q = tf->goto_queue;
+ qe = q + tf->goto_queue_active;
+
+ if (tf->may_return)
+ {
+ /* Reachable by return expressions only. Redirect them. */
+ tree return_val = NULL;
+ for (; q < qe; ++q)
+ do_return_redirection (q, finally_label, NULL, &return_val);
+ replace_goto_queue (tf);
+ }
+ else
+ {
+ /* Reachable by goto expressions only. Redirect them. */
+ for (; q < qe; ++q)
+ do_goto_redirection (q, finally_label, NULL, tf);
+ replace_goto_queue (tf);
+
+ if (VEC_index (tree, tf->dest_array, 0) == tf->fallthru_label)
+ {
+ /* Reachable by goto to fallthru label only. Redirect it
+ to the new label (already created, sadly), and do not
+ emit the final branch out, or the fallthru label. */
+ tf->fallthru_label = NULL;
+ return;
+ }
+ }
+
+ /* Place the original return/goto to the original destination
+ immediately after the finally block. */
+ x = tf->goto_queue[0].cont_stmt;
+ gimple_seq_add_stmt (&tf->top_p_seq, x);
+ maybe_record_in_goto_queue (state, x);
+}
+
+/* A subroutine of lower_try_finally. There are multiple edges incoming
+ and outgoing from the finally block. Implement this by duplicating the
+ finally block for every destination. */
+
+static void
+lower_try_finally_copy (struct leh_state *state, struct leh_tf_state *tf)
+{
+ gimple_seq finally;
+ gimple_seq new_stmt;
+ gimple_seq seq;
+ gimple x;
+ tree tmp;
+
+ finally = gimple_try_cleanup (tf->top_p);
+ tf->top_p_seq = gimple_try_eval (tf->top_p);
+ new_stmt = NULL;
+
+ if (tf->may_fallthru)
+ {
+ seq = lower_try_finally_dup_block (finally, state);
+ lower_eh_constructs_1 (state, seq);
+ gimple_seq_add_seq (&new_stmt, seq);
+
+ tmp = lower_try_finally_fallthru_label (tf);
+ x = gimple_build_goto (tmp);
+ gimple_seq_add_stmt (&new_stmt, x);
+ }
+
+ if (tf->may_throw)
+ {
+ x = gimple_build_label (tf->eh_label);
+ gimple_seq_add_stmt (&new_stmt, x);
+
+ seq = lower_try_finally_dup_block (finally, state);
+ lower_eh_constructs_1 (state, seq);
+ gimple_seq_add_seq (&new_stmt, seq);
+
+ x = gimple_build_resx (get_eh_region_number (tf->region));
+ gimple_seq_add_stmt (&new_stmt, x);
+ }
+
+ if (tf->goto_queue)
+ {
+ struct goto_queue_node *q, *qe;
+ tree return_val = NULL;
+ int return_index, index;
+ struct labels_s
+ {
+ struct goto_queue_node *q;
+ tree label;
+ } *labels;
+
+ return_index = VEC_length (tree, tf->dest_array);
+ labels = XCNEWVEC (struct labels_s, return_index + 1);
+
+ q = tf->goto_queue;
+ qe = q + tf->goto_queue_active;
+ for (; q < qe; q++)
+ {
+ index = q->index < 0 ? return_index : q->index;
+
+ if (!labels[index].q)
+ labels[index].q = q;
+ }
+
+ for (index = 0; index < return_index + 1; index++)
+ {
+ tree lab;
+
+ q = labels[index].q;
+ if (! q)
+ continue;
+
+ lab = labels[index].label = create_artificial_label ();
+
+ if (index == return_index)
+ do_return_redirection (q, lab, NULL, &return_val);
+ else
+ do_goto_redirection (q, lab, NULL, tf);
+
+ x = gimple_build_label (lab);
+ gimple_seq_add_stmt (&new_stmt, x);
+
+ seq = lower_try_finally_dup_block (finally, state);
+ lower_eh_constructs_1 (state, seq);
+ gimple_seq_add_seq (&new_stmt, seq);
+
+ gimple_seq_add_stmt (&new_stmt, q->cont_stmt);
+ maybe_record_in_goto_queue (state, q->cont_stmt);
+ }
+
+ for (q = tf->goto_queue; q < qe; q++)
+ {
+ tree lab;
+
+ index = q->index < 0 ? return_index : q->index;
+
+ if (labels[index].q == q)
+ continue;
+
+ lab = labels[index].label;
+
+ if (index == return_index)
+ do_return_redirection (q, lab, NULL, &return_val);
+ else
+ do_goto_redirection (q, lab, NULL, tf);
+ }
+
+ replace_goto_queue (tf);
+ free (labels);
+ }
+
+ /* Need to link new stmts after running replace_goto_queue due
+ to not wanting to process the same goto stmts twice. */
+ gimple_seq_add_seq (&tf->top_p_seq, new_stmt);
+}
+
+/* A subroutine of lower_try_finally. There are multiple edges incoming
+ and outgoing from the finally block. Implement this by instrumenting
+ each incoming edge and creating a switch statement at the end of the
+ finally block that branches to the appropriate destination. */
+
+static void
+lower_try_finally_switch (struct leh_state *state, struct leh_tf_state *tf)
+{
+ struct goto_queue_node *q, *qe;
+ tree return_val = NULL;
+ tree finally_tmp, finally_label;
+ int return_index, eh_index, fallthru_index;
+ int nlabels, ndests, j, last_case_index;
+ tree last_case;
+ VEC (tree,heap) *case_label_vec;
+ gimple_seq switch_body;
+ gimple x;
+ tree tmp;
+ gimple switch_stmt;
+ gimple_seq finally;
+ struct pointer_map_t *cont_map = NULL;
+
+ switch_body = gimple_seq_alloc ();
+
+ /* Mash the TRY block to the head of the chain. */
+ finally = gimple_try_cleanup (tf->top_p);
+ tf->top_p_seq = gimple_try_eval (tf->top_p);
+
+ /* Lower the finally block itself. */
+ lower_eh_constructs_1 (state, finally);
+
+ /* Prepare for switch statement generation. */
+ nlabels = VEC_length (tree, tf->dest_array);
+ return_index = nlabels;
+ eh_index = return_index + tf->may_return;
+ fallthru_index = eh_index + tf->may_throw;
+ ndests = fallthru_index + tf->may_fallthru;
+
+ finally_tmp = create_tmp_var (integer_type_node, "finally_tmp");
+ finally_label = create_artificial_label ();
+
+ /* We use VEC_quick_push on case_label_vec throughout this function,
+ since we know the size in advance and allocate precisely as muce
+ space as needed. */
+ case_label_vec = VEC_alloc (tree, heap, ndests);
+ last_case = NULL;
+ last_case_index = 0;
+
+ /* Begin inserting code for getting to the finally block. Things
+ are done in this order to correspond to the sequence the code is
+ layed out. */
+
+ if (tf->may_fallthru)
+ {
+ x = gimple_build_assign (finally_tmp, build_int_cst (integer_type_node,
+ 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 ());
+ 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);
+
+ tmp = lower_try_finally_fallthru_label (tf);
+ x = gimple_build_goto (tmp);
+ gimple_seq_add_stmt (&switch_body, x);
+ }
+
+ if (tf->may_throw)
+ {
+ x = gimple_build_label (tf->eh_label);
+ gimple_seq_add_stmt (&tf->top_p_seq, x);
+
+ x = gimple_build_assign (finally_tmp, build_int_cst (integer_type_node,
+ eh_index));
+ gimple_seq_add_stmt (&tf->top_p_seq, x);
+
+ last_case = build3 (CASE_LABEL_EXPR, void_type_node,
+ build_int_cst (NULL_TREE, eh_index), NULL,
+ create_artificial_label ());
+ 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);
+ }
+
+ x = gimple_build_label (finally_label);
+ gimple_seq_add_stmt (&tf->top_p_seq, x);
+
+ gimple_seq_add_seq (&tf->top_p_seq, finally);
+
+ /* Redirect each incoming goto edge. */
+ q = tf->goto_queue;
+ qe = q + tf->goto_queue_active;
+ j = last_case_index + tf->may_return;
+ /* Prepare the assignments to finally_tmp that are executed upon the
+ entrance through a particular edge. */
+ for (; q < qe; ++q)
+ {
+ gimple_seq mod;
+ int switch_id;
+ unsigned int case_index;
+
+ mod = gimple_seq_alloc ();
+
+ if (q->index < 0)
+ {
+ x = gimple_build_assign (finally_tmp,
+ build_int_cst (integer_type_node,
+ return_index));
+ gimple_seq_add_stmt (&mod, x);
+ do_return_redirection (q, finally_label, mod, &return_val);
+ switch_id = return_index;
+ }
+ else
+ {
+ x = gimple_build_assign (finally_tmp,
+ build_int_cst (integer_type_node, q->index));
+ gimple_seq_add_stmt (&mod, x);
+ do_goto_redirection (q, finally_label, mod, tf);
+ switch_id = q->index;
+ }
+
+ case_index = j + q->index;
+ if (VEC_length (tree, case_label_vec) <= case_index
+ || !VEC_index (tree, case_label_vec, case_index))
+ {
+ tree case_lab;
+ void **slot;
+ case_lab = build3 (CASE_LABEL_EXPR, void_type_node,
+ build_int_cst (NULL_TREE, 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
+ order. */
+ if (!cont_map)
+ cont_map = pointer_map_create ();
+ slot = pointer_map_insert (cont_map, case_lab);
+ *slot = q->cont_stmt;
+ VEC_quick_push (tree, case_label_vec, case_lab);
+ }
+ }
+ for (j = last_case_index; j < last_case_index + nlabels; j++)
+ {
+ tree label;
+ gimple cont_stmt;
+ void **slot;
+
+ last_case = VEC_index (tree, case_label_vec, j);
+
+ gcc_assert (last_case);
+ gcc_assert (cont_map);
+
+ slot = pointer_map_contains (cont_map, last_case);
+ /* As the comment above suggests, CASE_LABEL (last_case) was just a
+ placeholder, it does not store an actual label, yet. */
+ gcc_assert (slot);
+ cont_stmt = *(gimple *) slot;
+
+ label = create_artificial_label ();
+ CASE_LABEL (last_case) = label;
+
+ x = gimple_build_label (label);
+ gimple_seq_add_stmt (&switch_body, x);
+ gimple_seq_add_stmt (&switch_body, cont_stmt);
+ maybe_record_in_goto_queue (state, cont_stmt);
+ }
+ if (cont_map)
+ pointer_map_destroy (cont_map);
+
+ replace_goto_queue (tf);
+
+ /* Make sure that the last case is the default label, as one is required.
+ Then sort the labels, which is also required in GIMPLE. */
+ CASE_LOW (last_case) = NULL;
+ sort_case_labels (case_label_vec);
+
+ /* Build the switch statement, setting last_case to be the default
+ label. */
+ switch_stmt = gimple_build_switch_vec (finally_tmp, last_case,
+ case_label_vec);
+
+ /* Need to link SWITCH_STMT after running replace_goto_queue
+ due to not wanting to process the same goto stmts twice. */
+ gimple_seq_add_stmt (&tf->top_p_seq, switch_stmt);
+ gimple_seq_add_seq (&tf->top_p_seq, switch_body);
+}
+
+/* Decide whether or not we are going to duplicate the finally block.
+ There are several considerations.
+
+ First, if this is Java, then the finally block contains code
+ written by the user. It has line numbers associated with it,
+ so duplicating the block means it's difficult to set a breakpoint.
+ Since controlling code generation via -g is verboten, we simply
+ never duplicate code without optimization.
+
+ Second, we'd like to prevent egregious code growth. One way to
+ do this is to estimate the size of the finally block, multiply
+ that by the number of copies we'd need to make, and compare against
+ the estimate of the size of the switch machinery we'd have to add. */
+
+static bool
+decide_copy_try_finally (int ndests, gimple_seq finally)
+{
+ int f_estimate, sw_estimate;
+
+ if (!optimize)
+ return false;
+
+ /* Finally estimate N times, plus N gotos. */
+ f_estimate = count_insns_seq (finally, &eni_size_weights);
+ f_estimate = (f_estimate + 1) * ndests;
+
+ /* Switch statement (cost 10), N variable assignments, N gotos. */
+ sw_estimate = 10 + 2 * ndests;
+
+ /* Optimize for size clearly wants our best guess. */
+ if (optimize_function_for_size_p (cfun))
+ return f_estimate < sw_estimate;
+
+ /* ??? These numbers are completely made up so far. */
+ if (optimize > 1)
+ return f_estimate < 100 || f_estimate < sw_estimate * 2;
+ else
+ return f_estimate < 40 || f_estimate * 2 < sw_estimate * 3;
+}
+
+
+/* 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
+ that record all the magic. This is complicated by the need to
+ arrange for the FINALLY block to be executed on all exits. */
+
+static gimple_seq
+lower_try_finally (struct leh_state *state, gimple tp)
+{
+ struct leh_tf_state this_tf;
+ struct leh_state this_state;
+ int ndests;
+
+ /* Process the try block. */
+
+ memset (&this_tf, 0, sizeof (this_tf));
+ 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, state->prev_try);
+ else
+ this_tf.region = NULL;
+
+ this_state.cur_region = this_tf.region;
+ this_state.prev_try = state->prev_try;
+ this_state.tf = &this_tf;
+
+ 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)
+ this_tf.may_throw = get_eh_region_may_contain_throw (this_tf.region);
+ if (this_tf.may_throw)
+ {
+ this_tf.eh_label = create_artificial_label ();
+ set_eh_region_tree_label (this_tf.region, this_tf.eh_label);
+ 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
+ determine how we process the finally block itself. */
+
+ ndests = VEC_length (tree, this_tf.dest_array);
+ ndests += this_tf.may_fallthru;
+ ndests += this_tf.may_return;
+ ndests += this_tf.may_throw;
+
+ /* If the FINALLY block is not reachable, dike it out. */
+ if (ndests == 0)
+ {
+ gimple_seq_add_seq (&this_tf.top_p_seq, gimple_try_eval (tp));
+ gimple_try_set_cleanup (tp, NULL);
+ }
+ /* If the finally block doesn't fall through, then any destination
+ we might try to impose there isn't reached either. There may be
+ some minor amount of cleanup and redirection still needed. */
+ else if (!gimple_seq_may_fallthru (gimple_try_cleanup (tp)))
+ lower_try_finally_nofallthru (state, &this_tf);
+
+ /* We can easily special-case redirection to a single destination. */
+ else if (ndests == 1)
+ lower_try_finally_onedest (state, &this_tf);
+ else if (decide_copy_try_finally (ndests, gimple_try_cleanup (tp)))
+ lower_try_finally_copy (state, &this_tf);
+ else
+ lower_try_finally_switch (state, &this_tf);
+
+ /* If someone requested we add a label at the end of the transformed
+ block, do so. */
+ if (this_tf.fallthru_label)
+ {
+ /* This must be reached only if ndests == 0. */
+ gimple x = gimple_build_label (this_tf.fallthru_label);
+ gimple_seq_add_stmt (&this_tf.top_p_seq, x);
+ }
+
+ VEC_free (tree, heap, this_tf.dest_array);
+ if (this_tf.goto_queue)
+ free (this_tf.goto_queue);
+ if (this_tf.goto_queue_map)
+ pointer_map_destroy (this_tf.goto_queue_map);
+
+ return this_tf.top_p_seq;
+}
+
+/* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_CATCH with a
+ list of GIMPLE_CATCH to a sequence of labels and blocks, plus the
+ exception region trees that records all the magic. */
+
+static gimple_seq
+lower_catch (struct leh_state *state, gimple tp)
+{
+ struct eh_region *try_region;
+ struct leh_state this_state;
+ gimple_stmt_iterator gsi;
+ tree out_label;
+
+ try_region = gen_eh_region_try (state->cur_region);
+ this_state.cur_region = try_region;
+ this_state.prev_try = 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);
+ }
+
+ out_label = NULL;
+ for (gsi = gsi_start (gimple_try_cleanup (tp)); !gsi_end_p (gsi); )
+ {
+ struct eh_region *catch_region;
+ tree eh_label;
+ gimple x, gcatch;
+
+ gcatch = gsi_stmt (gsi);
+ catch_region = gen_eh_region_catch (try_region,
+ gimple_catch_types (gcatch));
+
+ this_state.cur_region = catch_region;
+ this_state.prev_try = state->prev_try;
+ lower_eh_constructs_1 (&this_state, gimple_catch_handler (gcatch));
+
+ eh_label = create_artificial_label ();
+ set_eh_region_tree_label (catch_region, eh_label);
+
+ x = gimple_build_label (eh_label);
+ gsi_insert_before (&gsi, x, GSI_SAME_STMT);
+
+ if (gimple_seq_may_fallthru (gimple_catch_handler (gcatch)))
+ {
+ if (!out_label)
+ out_label = create_artificial_label ();
+
+ x = gimple_build_goto (out_label);
+ gimple_seq_add_stmt (gimple_catch_handler_ptr (gcatch), 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);
+}
+
+/* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with a
+ GIMPLE_EH_FILTER to a sequence of labels and blocks, plus the exception
+ region trees that record all the magic. */
+
+static gimple_seq
+lower_eh_filter (struct leh_state *state, gimple tp)
+{
+ struct leh_state this_state;
+ struct eh_region *this_region;
+ gimple inner;
+ tree eh_label;
+
+ 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_state = *state;
+ this_state.cur_region = this_region;
+ /* For must not throw regions any cleanup regions inside it
+ can't reach outer catch regions. */
+ if (gimple_eh_filter_must_not_throw (inner))
+ this_state.prev_try = NULL;
+
+ lower_eh_constructs_1 (&this_state, gimple_try_eval (tp));
+
+ if (!get_eh_region_may_contain_throw (this_region))
+ {
+ return gimple_try_eval (tp);
+ }
+
+ lower_eh_constructs_1 (state, gimple_eh_filter_failure (inner));
+ gimple_try_set_cleanup (tp, gimple_eh_filter_failure (inner));
+
+ eh_label = create_artificial_label ();
+ set_eh_region_tree_label (this_region, eh_label);
+
+ return frob_into_branch_around (tp, eh_label, NULL);
+}
+
+/* Implement a cleanup expression. This is similar to try-finally,
+ except that we only execute the cleanup block for exception edges. */
+
+static gimple_seq
+lower_cleanup (struct leh_state *state, gimple tp)
+{
+ struct leh_state this_state;
+ struct eh_region *this_region;
+ struct leh_tf_state fake_tf;
+ gimple_seq result;
+
+ /* If not using eh, then exception-only cleanups are no-ops. */
+ if (!flag_exceptions)
+ {
+ result = gimple_try_eval (tp);
+ lower_eh_constructs_1 (state, result);
+ return result;
+ }
+
+ this_region = gen_eh_region_cleanup (state->cur_region, state->prev_try);
+ 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);
+ }
+
+ /* Build enough of a try-finally state so that we can reuse
+ honor_protect_cleanup_actions. */
+ memset (&fake_tf, 0, sizeof (fake_tf));
+ fake_tf.top_p = tp;
+ fake_tf.outer = state;
+ fake_tf.region = this_region;
+ fake_tf.may_fallthru = gimple_seq_may_fallthru (gimple_try_eval (tp));
+ fake_tf.may_throw = true;
+
+ fake_tf.eh_label = create_artificial_label ();
+ set_eh_region_tree_label (this_region, fake_tf.eh_label);
+
+ honor_protect_cleanup_actions (state, NULL, &fake_tf);
+
+ if (fake_tf.may_throw)
+ {
+ /* 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);
+ }
+ else
+ {
+ /* In this case honor_protect_cleanup_actions did nearly all of
+ the work. All we have left is to append the fallthru_label. */
+
+ result = gimple_try_eval (tp);
+ if (fake_tf.fallthru_label)
+ {
+ gimple x = gimple_build_label (fake_tf.fallthru_label);
+ gimple_seq_add_stmt (&result, x);
+ }
+ }
+ return result;
+}
+
+
+
+/* Main loop for lowering eh constructs. Also moves gsi to the next
+ statement. */
+
+static void
+lower_eh_constructs_2 (struct leh_state *state, gimple_stmt_iterator *gsi)
+{
+ gimple_seq replace;
+ gimple x;
+ gimple stmt = gsi_stmt (*gsi);
+
+ switch (gimple_code (stmt))
+ {
+ case GIMPLE_CALL:
+ case GIMPLE_ASSIGN:
+ /* Look for things that can throw exceptions, and record them. */
+ if (state->cur_region && stmt_could_throw_p (stmt))
+ {
+ record_stmt_eh_region (state->cur_region, stmt);
+ note_eh_region_may_contain_throw (state->cur_region);
+ }
+ break;
+
+ case GIMPLE_COND:
+ case GIMPLE_GOTO:
+ case GIMPLE_RETURN:
+ maybe_record_in_goto_queue (state, stmt);
+ break;
+
+ case GIMPLE_SWITCH:
+ verify_norecord_switch_expr (state, stmt);
+ break;
+
+ case GIMPLE_TRY:
+ if (gimple_try_kind (stmt) == GIMPLE_TRY_FINALLY)
+ replace = lower_try_finally (state, stmt);
+ else
+ {
+ x = gimple_seq_first_stmt (gimple_try_cleanup (stmt));
+ switch (gimple_code (x))
+ {
+ case GIMPLE_CATCH:
+ replace = lower_catch (state, stmt);
+ break;
+ case GIMPLE_EH_FILTER:
+ replace = lower_eh_filter (state, stmt);
+ break;
+ default:
+ replace = lower_cleanup (state, stmt);
+ break;
+ }
+ }
+
+ /* Remove the old stmt and insert the transformed sequence
+ instead. */
+ gsi_insert_seq_before (gsi, replace, GSI_SAME_STMT);
+ gsi_remove (gsi, true);
+
+ /* Return since we don't want gsi_next () */
+ return;
+
+ default:
+ /* A type, a decl, or some kind of statement that we're not
+ interested in. Don't walk them. */
+ break;
+ }
+
+ gsi_next (gsi);
+}
+
+/* A helper to unwrap a gimple_seq and feed stmts to lower_eh_constructs_2. */
+
+static void
+lower_eh_constructs_1 (struct leh_state *state, gimple_seq seq)
+{
+ gimple_stmt_iterator gsi;
+ for (gsi = gsi_start (seq); !gsi_end_p (gsi);)
+ lower_eh_constructs_2 (state, &gsi);
+}
+
+static unsigned int
+lower_eh_constructs (void)
+{
+ struct leh_state null_state;
+
+ gimple_seq bodyp = gimple_body (current_function_decl);
+
+ finally_tree = htab_create (31, struct_ptr_hash, struct_ptr_eq, free);
+
+ collect_finally_tree_1 (bodyp, NULL);
+
+ memset (&null_state, 0, sizeof (null_state));
+ lower_eh_constructs_1 (&null_state, bodyp);
+
+ htab_delete (finally_tree);
+
+ collect_eh_region_array ();
+ return 0;
+}
+
+struct gimple_opt_pass pass_lower_eh =
+{
+ {
+ GIMPLE_PASS,
+ "eh", /* name */
+ NULL, /* gate */
+ lower_eh_constructs, /* execute */
+ NULL, /* sub */
+ NULL, /* next */
+ 0, /* static_pass_number */
+ TV_TREE_EH, /* tv_id */
+ PROP_gimple_lcf, /* properties_required */
+ PROP_gimple_leh, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ TODO_dump_func /* todo_flags_finish */
+ }
+};
+
+\f
+/* Construct EH edges for STMT. */
+
+static void
+make_eh_edge (struct eh_region *region, void *data)
+{
+ gimple stmt;
+ tree lab;
+ basic_block src, dst;
+
+ stmt = (gimple) data;
+ lab = get_eh_region_tree_label (region);
+
+ src = gimple_bb (stmt);
+ dst = label_to_block (lab);
+
+ make_edge (src, dst, EDGE_ABNORMAL | EDGE_EH);
+}
+
+void
+make_eh_edges (gimple stmt)
+{
+ int region_nr;
+ bool is_resx;
+
+ 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;
+ }
+
+ foreach_reachable_handler (region_nr, is_resx, make_eh_edge, stmt);
+}
+
+static bool mark_eh_edge_found_error;
+
+/* Mark edge make_eh_edge would create for given region by setting it aux
+ field, output error if something goes wrong. */
+
+static void
+mark_eh_edge (struct eh_region *region, void *data)
+{
+ gimple stmt;
+ tree lab;
+ basic_block src, dst;
+ edge e;
+
+ stmt = (gimple) data;
+ lab = get_eh_region_tree_label (region);
+
+ src = gimple_bb (stmt);
+ dst = label_to_block (lab);
+
+ 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))
+ {
+ error ("EH edge %i->%i miss EH flag", src->index, dst->index);
+ mark_eh_edge_found_error = true;
+ }
+ else if (e->aux)
+ {
+ /* ??? might not be mistake. */
+ error ("EH edge %i->%i has duplicated regions", src->index, dst->index);
+ mark_eh_edge_found_error = true;
+ }
+ 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;
+
+ FOR_EACH_EDGE (e, ei, bb->succs)
+ gcc_assert (!e->aux);
+ mark_eh_edge_found_error = 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)
+ {
+ 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))
+ {
+ error ("BB %i last statement has incorrectly set region", bb->index);
+ return true;
+ }
+ is_resx = false;
+ }
+
+ foreach_reachable_handler (region_nr, is_resx, mark_eh_edge, stmt);
+ FOR_EACH_EDGE (e, ei, bb->succs)
+ {
+ if ((e->flags & EDGE_EH) && !e->aux)
+ {
+ error ("unnecessary EH edge %i->%i", bb->index, e->dest->index);
+ mark_eh_edge_found_error = true;
+ return true;
+ }
+ e->aux = NULL;
+ }
+
+ return mark_eh_edge_found_error;
+}
+
+\f
+/* Helper function for operation_could_trap_p and stmt_could_throw_p. */
+
+bool
+operation_could_trap_helper_p (enum tree_code op,
+ bool fp_operation,
+ bool honor_trapv,
+ bool honor_nans,
+ bool honor_snans,
+ tree divisor,
+ bool *handled)
+{
+ *handled = true;
+ switch (op)
+ {
+ case TRUNC_DIV_EXPR:
+ case CEIL_DIV_EXPR:
+ case FLOOR_DIV_EXPR:
+ case ROUND_DIV_EXPR:
+ case EXACT_DIV_EXPR:
+ case CEIL_MOD_EXPR:
+ case FLOOR_MOD_EXPR:
+ case ROUND_MOD_EXPR:
+ case TRUNC_MOD_EXPR:
+ case RDIV_EXPR:
+ if (honor_snans || honor_trapv)
+ return true;
+ if (fp_operation)
+ return flag_trapping_math;
+ if (!TREE_CONSTANT (divisor) || integer_zerop (divisor))
+ return true;
+ return false;
+
+ case LT_EXPR:
+ case LE_EXPR:
+ case GT_EXPR:
+ case GE_EXPR:
+ case LTGT_EXPR:
+ /* Some floating point comparisons may trap. */
+ return honor_nans;
+
+ case EQ_EXPR:
+ case NE_EXPR:
+ case UNORDERED_EXPR:
+ case ORDERED_EXPR:
+ case UNLT_EXPR:
+ case UNLE_EXPR:
+ case UNGT_EXPR:
+ case UNGE_EXPR:
+ case UNEQ_EXPR:
+ return honor_snans;
+
+ case CONVERT_EXPR:
+ case FIX_TRUNC_EXPR:
+ /* Conversion of floating point might trap. */
+ return honor_nans;
+
+ case NEGATE_EXPR:
+ case ABS_EXPR:
+ case CONJ_EXPR:
+ /* These operations don't trap with floating point. */
+ if (honor_trapv)
+ return true;
+ return false;
+
+ case PLUS_EXPR:
+ case MINUS_EXPR:
+ case MULT_EXPR:
+ /* Any floating arithmetic may trap. */
+ if (fp_operation && flag_trapping_math)
+ return true;
+ if (honor_trapv)
+ return true;
+ return false;
+
+ default:
+ /* Any floating arithmetic may trap. */
+ if (fp_operation && flag_trapping_math)
+ return true;
+
+ *handled = false;
+ return false;
+ }
+}
+
+/* Return true if operation OP may trap. FP_OPERATION is true if OP is applied
+ on floating-point values. HONOR_TRAPV is true if OP is applied on integer
+ type operands that may trap. If OP is a division operator, DIVISOR contains
+ the value of the divisor. */
+
+bool
+operation_could_trap_p (enum tree_code op, bool fp_operation, bool honor_trapv,
+ tree divisor)
+{
+ bool honor_nans = (fp_operation && flag_trapping_math
+ && !flag_finite_math_only);
+ bool honor_snans = fp_operation && flag_signaling_nans != 0;
+ bool handled;
+
+ if (TREE_CODE_CLASS (op) != tcc_comparison
+ && TREE_CODE_CLASS (op) != tcc_unary
+ && TREE_CODE_CLASS (op) != tcc_binary)
+ return false;
+
+ return operation_could_trap_helper_p (op, fp_operation, honor_trapv,
+ honor_nans, honor_snans, divisor,
+ &handled);
+}
+
+/* Return true if EXPR can trap, as in dereferencing an invalid pointer
+ location or floating point arithmetic. C.f. the rtl version, may_trap_p.
+ This routine expects only GIMPLE lhs or rhs input. */
+
+bool
+tree_could_trap_p (tree expr)
+{
+ enum tree_code code;
+ bool fp_operation = false;
+ bool honor_trapv = false;
+ tree t, base, div = NULL_TREE;
+
+ if (!expr)
+ return false;
+
+ code = TREE_CODE (expr);
+ t = TREE_TYPE (expr);
+
+ if (t)
+ {
+ if (COMPARISON_CLASS_P (expr))
+ fp_operation = FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (expr, 0)));
+ else
+ fp_operation = FLOAT_TYPE_P (t);
+ honor_trapv = INTEGRAL_TYPE_P (t) && TYPE_OVERFLOW_TRAPS (t);
+ }
+
+ if (TREE_CODE_CLASS (code) == tcc_binary)
+ div = TREE_OPERAND (expr, 1);
+ if (operation_could_trap_p (code, fp_operation, honor_trapv, div))
+ return true;
+
+ restart:
+ switch (code)
+ {
+ case TARGET_MEM_REF:
+ /* For TARGET_MEM_REFs use the information based on the original
+ reference. */
+ expr = TMR_ORIGINAL (expr);
+ code = TREE_CODE (expr);
+ goto restart;
+
+ case COMPONENT_REF:
+ case REALPART_EXPR:
+ case IMAGPART_EXPR:
+ case BIT_FIELD_REF:
+ case VIEW_CONVERT_EXPR:
+ case WITH_SIZE_EXPR:
+ expr = TREE_OPERAND (expr, 0);
+ code = TREE_CODE (expr);
+ goto restart;
+
+ case ARRAY_RANGE_REF:
+ 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:
+ case ALIGN_INDIRECT_REF:
+ case MISALIGNED_INDIRECT_REF:
+ return !TREE_THIS_NOTRAP (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. */
+ if (!t || !DECL_P (t) || DECL_WEAK (t))
+ return true;
+ return false;
+
+ default:
+ return false;
+ }
+}
+
+
+/* Helper for stmt_could_throw_p. Return true if STMT (assumed to be a
+ an assignment or a conditional) may throw. */
+
+static bool
+stmt_could_throw_1_p (gimple stmt)
+{
+ enum tree_code code = gimple_expr_code (stmt);
+ bool honor_nans = false;
+ bool honor_snans = false;
+ bool fp_operation = false;
+ bool honor_trapv = false;
+ tree t;
+ size_t i;
+ bool handled, ret;
+
+ if (TREE_CODE_CLASS (code) == tcc_comparison
+ || TREE_CODE_CLASS (code) == tcc_unary
+ || TREE_CODE_CLASS (code) == tcc_binary)
+ {
+ t = gimple_expr_type (stmt);
+ fp_operation = FLOAT_TYPE_P (t);
+ if (fp_operation)
+ {
+ honor_nans = flag_trapping_math && !flag_finite_math_only;
+ honor_snans = flag_signaling_nans != 0;
+ }
+ else if (INTEGRAL_TYPE_P (t) && TYPE_OVERFLOW_TRAPS (t))
+ honor_trapv = true;
+ }
+
+ /* Check if the main expression may trap. */
+ t = is_gimple_assign (stmt) ? gimple_assign_rhs2 (stmt) : NULL;
+ ret = operation_could_trap_helper_p (code, fp_operation, honor_trapv,
+ honor_nans, honor_snans, t,
+ &handled);
+ if (handled)
+ return ret;
+
+ /* If the expression does not trap, see if any of the individual operands may
+ trap. */
+ for (i = 0; i < gimple_num_ops (stmt); i++)
+ if (tree_could_trap_p (gimple_op (stmt, i)))
+ return true;
+
+ return false;
+}
+
+
+/* Return true if statement STMT could throw an exception. */
+
+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;
+
+ /* 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;
+
+ if (code == GIMPLE_ASSIGN || code == GIMPLE_COND)
+ return stmt_could_throw_1_p (stmt);
+ else if (is_gimple_call (stmt))
+ {
+ tree t = gimple_call_fndecl (stmt);
+
+ /* Assume that calls to weak functions may trap. */
+ if (!t || !DECL_P (t) || DECL_WEAK (t))
+ return true;
+
+ return (gimple_call_flags (stmt) & ECF_NOTHROW) == 0;
+ }
+ else if (gimple_code (stmt) == GIMPLE_ASM)
+ return (gimple_asm_volatile_p (stmt));
+ else
+ gcc_unreachable ();
+
+ return false;
+}
+
+
+/* Return true if expression T could throw an exception. */
+
+bool
+tree_could_throw_p (tree t)
+{
+ if (!flag_exceptions)
+ return false;
+ if (TREE_CODE (t) == MODIFY_EXPR)
+ {
+ if (flag_non_call_exceptions
+ && tree_could_trap_p (TREE_OPERAND (t, 0)))
+ return true;
+ t = TREE_OPERAND (t, 1);
+ }
+
+ if (TREE_CODE (t) == WITH_SIZE_EXPR)
+ t = TREE_OPERAND (t, 0);
+ if (TREE_CODE (t) == CALL_EXPR)
+ return (call_expr_flags (t) & ECF_NOTHROW) == 0;
+ if (flag_non_call_exceptions)
+ return tree_could_trap_p (t);
+ return false;
+}
+
+
+/* Return true if STMT can throw an exception that is caught within
+ the current function (CFUN). */
+
+bool
+stmt_can_throw_internal (gimple stmt)
+{
+ int region_nr;
+ bool is_resx = 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 false;
+
+ return can_throw_internal_1 (region_nr, is_resx);
+}
+
+
+/* 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)
+{
+ int region_nr = lookup_stmt_eh_region (old_stmt);
+
+ if (region_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);
+ if (new_stmt_could_throw)
+ {
+ add_stmt_to_eh_region (new_stmt, region_nr);
+ return false;
+ }
+ else
+ return true;
+ }
+
+ return false;
+}
+\f
+/* 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
+ this only handles handlers consisting of a single call, as that's the
+ important case for C++: a destructor call for a particular object showing
+ up in multiple handlers. */
+
+static bool
+same_handler_p (gimple_seq oneh, gimple_seq twoh)
+{
+ gimple_stmt_iterator gsi;
+ gimple ones, twos;
+ unsigned int ai;
+
+ gsi = gsi_start (oneh);
+ if (!gsi_one_before_end_p (gsi))
+ return false;
+ ones = gsi_stmt (gsi);
+
+ gsi = gsi_start (twoh);
+ if (!gsi_one_before_end_p (gsi))
+ return false;
+ twos = gsi_stmt (gsi);
+
+ if (!is_gimple_call (ones)
+ || !is_gimple_call (twos)
+ || gimple_call_lhs (ones)
+ || gimple_call_lhs (twos)
+ || gimple_call_chain (ones)
+ || gimple_call_chain (twos)
+ || !operand_equal_p (gimple_call_fn (ones), gimple_call_fn (twos), 0)
+ || gimple_call_num_args (ones) != gimple_call_num_args (twos))
+ return false;
+
+ 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))
+ return false;
+
+ return true;
+}
+
+/* Optimize
+ try { A() } finally { try { ~B() } catch { ~A() } }
+ try { ... } finally { ~A() }
+ into
+ try { A() } catch { ~B() }
+ try { ~B() ... } finally { ~A() }
+
+ This occurs frequently in C++, where A is a local variable and B is a
+ temporary used in the initializer for A. */
+
+static void
+optimize_double_finally (gimple one, gimple two)
+{
+ gimple oneh;
+ gimple_stmt_iterator gsi;
+
+ gsi = gsi_start (gimple_try_cleanup (one));
+ if (!gsi_one_before_end_p (gsi))
+ return;
+
+ oneh = gsi_stmt (gsi);
+ if (gimple_code (oneh) != GIMPLE_TRY
+ || gimple_try_kind (oneh) != GIMPLE_TRY_CATCH)
+ return;
+
+ if (same_handler_p (gimple_try_cleanup (oneh), gimple_try_cleanup (two)))
+ {
+ gimple_seq seq = gimple_try_eval (oneh);
+
+ gimple_try_set_cleanup (one, seq);
+ gimple_try_set_kind (one, GIMPLE_TRY_CATCH);
+ seq = copy_gimple_seq_and_replace_locals (seq);
+ gimple_seq_add_seq (&seq, gimple_try_eval (two));
+ gimple_try_set_eval (two, seq);
+ }
+}
+
+/* Perform EH refactoring optimizations that are simpler to do when code
+ flow has been lowered but EH structures haven't. */
+
+static void
+refactor_eh_r (gimple_seq seq)
+{
+ gimple_stmt_iterator gsi;
+ gimple one, two;
+
+ one = NULL;
+ two = NULL;
+ gsi = gsi_start (seq);
+ while (1)
+ {
+ one = two;
+ if (gsi_end_p (gsi))
+ two = NULL;
+ else
+ two = gsi_stmt (gsi);
+ if (one
+ && two
+ && gimple_code (one) == GIMPLE_TRY
+ && gimple_code (two) == GIMPLE_TRY
+ && gimple_try_kind (one) == GIMPLE_TRY_FINALLY
+ && gimple_try_kind (two) == GIMPLE_TRY_FINALLY)
+ optimize_double_finally (one, two);
+ if (one)
+ switch (gimple_code (one))
+ {
+ case GIMPLE_TRY:
+ refactor_eh_r (gimple_try_eval (one));
+ refactor_eh_r (gimple_try_cleanup (one));
+ break;
+ case GIMPLE_CATCH:
+ refactor_eh_r (gimple_catch_handler (one));
+ break;
+ case GIMPLE_EH_FILTER:
+ refactor_eh_r (gimple_eh_filter_failure (one));
+ break;
+ default:
+ break;
+ }
+ if (two)
+ gsi_next (&gsi);
+ else
+ break;
+ }
+}
+
+static unsigned
+refactor_eh (void)
+{
+ refactor_eh_r (gimple_body (current_function_decl));
+ return 0;
+}
+
+struct gimple_opt_pass pass_refactor_eh =
+{
+ {
+ GIMPLE_PASS,
+ "ehopt", /* name */
+ NULL, /* gate */
+ refactor_eh, /* 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_flags_finish */
+ }
+};