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2107 lines
56 KiB
C
2107 lines
56 KiB
C
/* Exception handling semantics and decomposition for trees.
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Copyright (C) 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GCC is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GCC; see the file COPYING. If not, write to
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the Free Software Foundation, 51 Franklin Street, Fifth Floor,
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Boston, MA 02110-1301, USA. */
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#include "config.h"
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#include "system.h"
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#include "coretypes.h"
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#include "tm.h"
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#include "tree.h"
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#include "rtl.h"
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#include "tm_p.h"
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#include "flags.h"
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#include "function.h"
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#include "except.h"
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#include "tree-flow.h"
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#include "tree-dump.h"
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#include "tree-inline.h"
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#include "tree-iterator.h"
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#include "tree-pass.h"
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#include "timevar.h"
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#include "langhooks.h"
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#include "ggc.h"
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#include "toplev.h"
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/* Nonzero if we are using EH to handle cleanups. */
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static int using_eh_for_cleanups_p = 0;
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void
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using_eh_for_cleanups (void)
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{
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using_eh_for_cleanups_p = 1;
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}
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/* Misc functions used in this file. */
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/* Compare and hash for any structure which begins with a canonical
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pointer. Assumes all pointers are interchangeable, which is sort
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of already assumed by gcc elsewhere IIRC. */
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static int
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struct_ptr_eq (const void *a, const void *b)
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{
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const void * const * x = (const void * const *) a;
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const void * const * y = (const void * const *) b;
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return *x == *y;
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}
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static hashval_t
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struct_ptr_hash (const void *a)
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{
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const void * const * x = (const void * const *) a;
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return (size_t)*x >> 4;
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}
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/* Remember and lookup EH region data for arbitrary statements.
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Really this means any statement that could_throw_p. We could
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stuff this information into the stmt_ann data structure, but:
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(1) We absolutely rely on this information being kept until
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we get to rtl. Once we're done with lowering here, if we lose
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the information there's no way to recover it!
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(2) There are many more statements that *cannot* throw as
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compared to those that can. We should be saving some amount
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of space by only allocating memory for those that can throw. */
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static void
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record_stmt_eh_region (struct eh_region *region, tree t)
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{
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if (!region)
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return;
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add_stmt_to_eh_region (t, get_eh_region_number (region));
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}
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void
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add_stmt_to_eh_region_fn (struct function *ifun, tree t, int num)
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{
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struct throw_stmt_node *n;
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void **slot;
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gcc_assert (num >= 0);
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gcc_assert (TREE_CODE (t) != RESX_EXPR);
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n = GGC_NEW (struct throw_stmt_node);
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n->stmt = t;
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n->region_nr = num;
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if (!get_eh_throw_stmt_table (ifun))
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set_eh_throw_stmt_table (ifun, htab_create_ggc (31, struct_ptr_hash,
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struct_ptr_eq,
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ggc_free));
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slot = htab_find_slot (get_eh_throw_stmt_table (ifun), n, INSERT);
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gcc_assert (!*slot);
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*slot = n;
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/* ??? For the benefit of calls.c, converting all this to rtl,
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we need to record the call expression, not just the outer
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modify statement. */
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if (TREE_CODE (t) == MODIFY_EXPR
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&& (t = get_call_expr_in (t)))
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add_stmt_to_eh_region_fn (ifun, t, num);
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}
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void
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add_stmt_to_eh_region (tree t, int num)
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{
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add_stmt_to_eh_region_fn (cfun, t, num);
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}
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bool
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remove_stmt_from_eh_region_fn (struct function *ifun, tree t)
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{
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struct throw_stmt_node dummy;
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void **slot;
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if (!get_eh_throw_stmt_table (ifun))
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return false;
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dummy.stmt = t;
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slot = htab_find_slot (get_eh_throw_stmt_table (ifun), &dummy,
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NO_INSERT);
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if (slot)
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{
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htab_clear_slot (get_eh_throw_stmt_table (ifun), slot);
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/* ??? For the benefit of calls.c, converting all this to rtl,
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we need to record the call expression, not just the outer
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modify statement. */
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if (TREE_CODE (t) == MODIFY_EXPR
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&& (t = get_call_expr_in (t)))
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remove_stmt_from_eh_region_fn (ifun, t);
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return true;
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}
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else
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return false;
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}
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bool
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remove_stmt_from_eh_region (tree t)
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{
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return remove_stmt_from_eh_region_fn (cfun, t);
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}
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int
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lookup_stmt_eh_region_fn (struct function *ifun, tree t)
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{
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struct throw_stmt_node *p, n;
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if (!get_eh_throw_stmt_table (ifun))
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return -2;
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n.stmt = t;
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p = (struct throw_stmt_node *) htab_find (get_eh_throw_stmt_table (ifun),
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&n);
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return (p ? p->region_nr : -1);
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}
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int
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lookup_stmt_eh_region (tree t)
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{
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/* We can get called from initialized data when -fnon-call-exceptions
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is on; prevent crash. */
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if (!cfun)
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return -1;
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return lookup_stmt_eh_region_fn (cfun, t);
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}
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/* First pass of EH node decomposition. Build up a tree of TRY_FINALLY_EXPR
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nodes and LABEL_DECL nodes. We will use this during the second phase to
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determine if a goto leaves the body of a TRY_FINALLY_EXPR node. */
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struct finally_tree_node
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{
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tree child, parent;
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};
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/* Note that this table is *not* marked GTY. It is short-lived. */
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static htab_t finally_tree;
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static void
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record_in_finally_tree (tree child, tree parent)
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{
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struct finally_tree_node *n;
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void **slot;
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n = XNEW (struct finally_tree_node);
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n->child = child;
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n->parent = parent;
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slot = htab_find_slot (finally_tree, n, INSERT);
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gcc_assert (!*slot);
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*slot = n;
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}
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static void
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collect_finally_tree (tree t, tree region)
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{
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tailrecurse:
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switch (TREE_CODE (t))
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{
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case LABEL_EXPR:
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record_in_finally_tree (LABEL_EXPR_LABEL (t), region);
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break;
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case TRY_FINALLY_EXPR:
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record_in_finally_tree (t, region);
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collect_finally_tree (TREE_OPERAND (t, 0), t);
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t = TREE_OPERAND (t, 1);
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goto tailrecurse;
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case TRY_CATCH_EXPR:
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collect_finally_tree (TREE_OPERAND (t, 0), region);
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t = TREE_OPERAND (t, 1);
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goto tailrecurse;
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case CATCH_EXPR:
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t = CATCH_BODY (t);
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goto tailrecurse;
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case EH_FILTER_EXPR:
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t = EH_FILTER_FAILURE (t);
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goto tailrecurse;
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case STATEMENT_LIST:
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{
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tree_stmt_iterator i;
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for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i))
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collect_finally_tree (tsi_stmt (i), region);
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}
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break;
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default:
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/* A type, a decl, or some kind of statement that we're not
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interested in. Don't walk them. */
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break;
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}
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}
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/* Use the finally tree to determine if a jump from START to TARGET
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would leave the try_finally node that START lives in. */
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static bool
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outside_finally_tree (tree start, tree target)
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{
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struct finally_tree_node n, *p;
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do
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{
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n.child = start;
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p = (struct finally_tree_node *) htab_find (finally_tree, &n);
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if (!p)
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return true;
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start = p->parent;
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}
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while (start != target);
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return false;
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}
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/* Second pass of EH node decomposition. Actually transform the TRY_FINALLY
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and TRY_CATCH nodes into a set of gotos, magic labels, and eh regions.
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The eh region creation is straight-forward, but frobbing all the gotos
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and such into shape isn't. */
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/* State of the world while lowering. */
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struct leh_state
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{
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/* What's "current" while constructing the eh region tree. These
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correspond to variables of the same name in cfun->eh, which we
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don't have easy access to. */
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struct eh_region *cur_region;
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struct eh_region *prev_try;
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/* Processing of TRY_FINALLY requires a bit more state. This is
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split out into a separate structure so that we don't have to
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copy so much when processing other nodes. */
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struct leh_tf_state *tf;
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};
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struct leh_tf_state
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{
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/* Pointer to the TRY_FINALLY node under discussion. The try_finally_expr
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is the original TRY_FINALLY_EXPR. We need to retain this so that
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outside_finally_tree can reliably reference the tree used in the
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collect_finally_tree data structures. */
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tree try_finally_expr;
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tree *top_p;
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/* The state outside this try_finally node. */
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struct leh_state *outer;
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/* The exception region created for it. */
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struct eh_region *region;
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/* The GOTO_QUEUE is is an array of GOTO_EXPR and RETURN_EXPR statements
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that are seen to escape this TRY_FINALLY_EXPR node. */
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struct goto_queue_node {
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tree stmt;
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tree repl_stmt;
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tree cont_stmt;
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int index;
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} *goto_queue;
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size_t goto_queue_size;
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size_t goto_queue_active;
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/* The set of unique labels seen as entries in the goto queue. */
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VEC(tree,heap) *dest_array;
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/* A label to be added at the end of the completed transformed
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sequence. It will be set if may_fallthru was true *at one time*,
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though subsequent transformations may have cleared that flag. */
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tree fallthru_label;
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/* A label that has been registered with except.c to be the
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landing pad for this try block. */
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tree eh_label;
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/* True if it is possible to fall out the bottom of the try block.
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Cleared if the fallthru is converted to a goto. */
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bool may_fallthru;
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/* True if any entry in goto_queue is a RETURN_EXPR. */
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bool may_return;
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/* True if the finally block can receive an exception edge.
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Cleared if the exception case is handled by code duplication. */
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bool may_throw;
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};
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static void lower_eh_filter (struct leh_state *, tree *);
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static void lower_eh_constructs_1 (struct leh_state *, tree *);
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/* Comparison function for qsort/bsearch. We're interested in
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searching goto queue elements for source statements. */
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static int
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goto_queue_cmp (const void *x, const void *y)
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{
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tree a = ((const struct goto_queue_node *)x)->stmt;
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tree b = ((const struct goto_queue_node *)y)->stmt;
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return (a == b ? 0 : a < b ? -1 : 1);
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}
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/* Search for STMT in the goto queue. Return the replacement,
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or null if the statement isn't in the queue. */
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static tree
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find_goto_replacement (struct leh_tf_state *tf, tree stmt)
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{
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struct goto_queue_node tmp, *ret;
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tmp.stmt = stmt;
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ret = (struct goto_queue_node *)
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bsearch (&tmp, tf->goto_queue, tf->goto_queue_active,
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sizeof (struct goto_queue_node), goto_queue_cmp);
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return (ret ? ret->repl_stmt : NULL);
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}
|
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|
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/* A subroutine of replace_goto_queue_1. Handles the sub-clauses of a
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lowered COND_EXPR. If, by chance, the replacement is a simple goto,
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then we can just splat it in, otherwise we add the new stmts immediately
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||
after the COND_EXPR and redirect. */
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static void
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replace_goto_queue_cond_clause (tree *tp, struct leh_tf_state *tf,
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tree_stmt_iterator *tsi)
|
||
{
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||
tree new, one, label;
|
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|
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new = find_goto_replacement (tf, *tp);
|
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if (!new)
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return;
|
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|
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one = expr_only (new);
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if (one && TREE_CODE (one) == GOTO_EXPR)
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{
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*tp = one;
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return;
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}
|
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label = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
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*tp = build_and_jump (&LABEL_EXPR_LABEL (label));
|
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tsi_link_after (tsi, label, TSI_CONTINUE_LINKING);
|
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tsi_link_after (tsi, new, TSI_CONTINUE_LINKING);
|
||
}
|
||
|
||
/* The real work of replace_goto_queue. Returns with TSI updated to
|
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point to the next statement. */
|
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|
||
static void replace_goto_queue_stmt_list (tree, struct leh_tf_state *);
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||
|
||
static void
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replace_goto_queue_1 (tree t, struct leh_tf_state *tf, tree_stmt_iterator *tsi)
|
||
{
|
||
switch (TREE_CODE (t))
|
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{
|
||
case GOTO_EXPR:
|
||
case RETURN_EXPR:
|
||
t = find_goto_replacement (tf, t);
|
||
if (t)
|
||
{
|
||
tsi_link_before (tsi, t, TSI_SAME_STMT);
|
||
tsi_delink (tsi);
|
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return;
|
||
}
|
||
break;
|
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|
||
case COND_EXPR:
|
||
replace_goto_queue_cond_clause (&COND_EXPR_THEN (t), tf, tsi);
|
||
replace_goto_queue_cond_clause (&COND_EXPR_ELSE (t), tf, tsi);
|
||
break;
|
||
|
||
case TRY_FINALLY_EXPR:
|
||
case TRY_CATCH_EXPR:
|
||
replace_goto_queue_stmt_list (TREE_OPERAND (t, 0), tf);
|
||
replace_goto_queue_stmt_list (TREE_OPERAND (t, 1), tf);
|
||
break;
|
||
case CATCH_EXPR:
|
||
replace_goto_queue_stmt_list (CATCH_BODY (t), tf);
|
||
break;
|
||
case EH_FILTER_EXPR:
|
||
replace_goto_queue_stmt_list (EH_FILTER_FAILURE (t), tf);
|
||
break;
|
||
|
||
case STATEMENT_LIST:
|
||
gcc_unreachable ();
|
||
|
||
default:
|
||
/* These won't have gotos in them. */
|
||
break;
|
||
}
|
||
|
||
tsi_next (tsi);
|
||
}
|
||
|
||
/* A subroutine of replace_goto_queue. Handles STATEMENT_LISTs. */
|
||
|
||
static void
|
||
replace_goto_queue_stmt_list (tree t, struct leh_tf_state *tf)
|
||
{
|
||
tree_stmt_iterator i = tsi_start (t);
|
||
while (!tsi_end_p (i))
|
||
replace_goto_queue_1 (tsi_stmt (i), tf, &i);
|
||
}
|
||
|
||
/* 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, tf);
|
||
}
|
||
|
||
/* For any GOTO_EXPR or RETURN_EXPR, 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, tree stmt)
|
||
{
|
||
struct leh_tf_state *tf = state->tf;
|
||
struct goto_queue_node *q;
|
||
size_t active, size;
|
||
int index;
|
||
|
||
if (!tf)
|
||
return;
|
||
|
||
switch (TREE_CODE (stmt))
|
||
{
|
||
case GOTO_EXPR:
|
||
{
|
||
tree lab = GOTO_DESTINATION (stmt);
|
||
|
||
/* 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 (lab) != LABEL_DECL)
|
||
return;
|
||
|
||
/* No need to record gotos that don't leave the try block. */
|
||
if (! outside_finally_tree (lab, tf->try_finally_expr))
|
||
return;
|
||
|
||
if (! tf->dest_array)
|
||
{
|
||
tf->dest_array = VEC_alloc (tree, heap, 10);
|
||
VEC_quick_push (tree, tf->dest_array, lab);
|
||
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) == lab)
|
||
break;
|
||
if (index == n)
|
||
VEC_safe_push (tree, heap, tf->dest_array, lab);
|
||
}
|
||
}
|
||
break;
|
||
|
||
case RETURN_EXPR:
|
||
tf->may_return = true;
|
||
index = -1;
|
||
break;
|
||
|
||
default:
|
||
gcc_unreachable ();
|
||
}
|
||
|
||
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 = stmt;
|
||
q->index = index;
|
||
}
|
||
|
||
#ifdef ENABLE_CHECKING
|
||
/* We do not process SWITCH_EXPRs 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 TRY_FINALLY_EXPRs. Verify this. */
|
||
|
||
static void
|
||
verify_norecord_switch_expr (struct leh_state *state, tree switch_expr)
|
||
{
|
||
struct leh_tf_state *tf = state->tf;
|
||
size_t i, n;
|
||
tree vec;
|
||
|
||
if (!tf)
|
||
return;
|
||
|
||
vec = SWITCH_LABELS (switch_expr);
|
||
n = TREE_VEC_LENGTH (vec);
|
||
|
||
for (i = 0; i < n; ++i)
|
||
{
|
||
tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
|
||
gcc_assert (!outside_finally_tree (lab, 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, tree mod,
|
||
tree *return_value_p)
|
||
{
|
||
tree ret_expr = TREE_OPERAND (q->stmt, 0);
|
||
tree x;
|
||
|
||
if (ret_expr)
|
||
{
|
||
/* 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. */
|
||
|
||
switch (TREE_CODE (ret_expr))
|
||
{
|
||
case RESULT_DECL:
|
||
if (!*return_value_p)
|
||
*return_value_p = ret_expr;
|
||
else
|
||
gcc_assert (*return_value_p == ret_expr);
|
||
q->cont_stmt = q->stmt;
|
||
break;
|
||
|
||
case MODIFY_EXPR:
|
||
{
|
||
tree result = TREE_OPERAND (ret_expr, 0);
|
||
tree new, old = TREE_OPERAND (ret_expr, 1);
|
||
|
||
if (!*return_value_p)
|
||
{
|
||
if (aggregate_value_p (TREE_TYPE (result),
|
||
TREE_TYPE (current_function_decl)))
|
||
/* If this function returns in memory, copy the argument
|
||
into the return slot now. Otherwise, we might need to
|
||
worry about magic return semantics, so we need to use a
|
||
temporary to hold the value until we're actually ready
|
||
to return. */
|
||
new = result;
|
||
else
|
||
new = create_tmp_var (TREE_TYPE (old), "rettmp");
|
||
*return_value_p = new;
|
||
}
|
||
else
|
||
new = *return_value_p;
|
||
|
||
x = build2 (MODIFY_EXPR, TREE_TYPE (new), new, old);
|
||
append_to_statement_list (x, &q->repl_stmt);
|
||
|
||
if (new == result)
|
||
x = result;
|
||
else
|
||
x = build2 (MODIFY_EXPR, TREE_TYPE (result), result, new);
|
||
q->cont_stmt = build1 (RETURN_EXPR, void_type_node, x);
|
||
}
|
||
|
||
default:
|
||
gcc_unreachable ();
|
||
}
|
||
}
|
||
else
|
||
{
|
||
/* If we don't return a value, all return statements are the same. */
|
||
q->cont_stmt = q->stmt;
|
||
}
|
||
|
||
if (mod)
|
||
append_to_statement_list (mod, &q->repl_stmt);
|
||
|
||
x = build1 (GOTO_EXPR, void_type_node, finlab);
|
||
append_to_statement_list (x, &q->repl_stmt);
|
||
}
|
||
|
||
/* Similar, but easier, for GOTO_EXPR. */
|
||
|
||
static void
|
||
do_goto_redirection (struct goto_queue_node *q, tree finlab, tree mod)
|
||
{
|
||
tree x;
|
||
|
||
q->cont_stmt = q->stmt;
|
||
if (mod)
|
||
append_to_statement_list (mod, &q->repl_stmt);
|
||
|
||
x = build1 (GOTO_EXPR, void_type_node, finlab);
|
||
append_to_statement_list (x, &q->repl_stmt);
|
||
}
|
||
|
||
/* We want to transform
|
||
try { body; } catch { stuff; }
|
||
to
|
||
body; goto over; lab: stuff; over:
|
||
|
||
T is a TRY_FINALLY or TRY_CATCH 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 void
|
||
frob_into_branch_around (tree *tp, tree lab, tree over)
|
||
{
|
||
tree x, op1;
|
||
|
||
op1 = TREE_OPERAND (*tp, 1);
|
||
*tp = TREE_OPERAND (*tp, 0);
|
||
|
||
if (block_may_fallthru (*tp))
|
||
{
|
||
if (!over)
|
||
over = create_artificial_label ();
|
||
x = build1 (GOTO_EXPR, void_type_node, over);
|
||
append_to_statement_list (x, tp);
|
||
}
|
||
|
||
if (lab)
|
||
{
|
||
x = build1 (LABEL_EXPR, void_type_node, lab);
|
||
append_to_statement_list (x, tp);
|
||
}
|
||
|
||
append_to_statement_list (op1, tp);
|
||
|
||
if (over)
|
||
{
|
||
x = build1 (LABEL_EXPR, void_type_node, over);
|
||
append_to_statement_list (x, tp);
|
||
}
|
||
}
|
||
|
||
/* A subroutine of lower_try_finally. Duplicate the tree rooted at T.
|
||
Make sure to record all new labels found. */
|
||
|
||
static tree
|
||
lower_try_finally_dup_block (tree t, struct leh_state *outer_state)
|
||
{
|
||
tree region = NULL;
|
||
|
||
t = unsave_expr_now (t);
|
||
|
||
if (outer_state->tf)
|
||
region = outer_state->tf->try_finally_expr;
|
||
collect_finally_tree (t, region);
|
||
|
||
return t;
|
||
}
|
||
|
||
/* 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;
|
||
if (!label)
|
||
{
|
||
label = create_artificial_label ();
|
||
tf->fallthru_label = label;
|
||
if (tf->outer->tf)
|
||
record_in_finally_tree (label, 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)
|
||
{
|
||
tree protect_cleanup_actions, finally, x;
|
||
tree_stmt_iterator i;
|
||
bool finally_may_fallthru;
|
||
|
||
/* First check for nothing to do. */
|
||
if (lang_protect_cleanup_actions)
|
||
protect_cleanup_actions = lang_protect_cleanup_actions ();
|
||
else
|
||
protect_cleanup_actions = NULL;
|
||
|
||
finally = TREE_OPERAND (*tf->top_p, 1);
|
||
|
||
/* 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 = block_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);
|
||
|
||
/* 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;
|
||
|
||
save_eptr = create_tmp_var (ptr_type_node, "save_eptr");
|
||
save_filt = create_tmp_var (integer_type_node, "save_filt");
|
||
|
||
i = tsi_start (finally);
|
||
x = build0 (EXC_PTR_EXPR, ptr_type_node);
|
||
x = build2 (MODIFY_EXPR, void_type_node, save_eptr, x);
|
||
tsi_link_before (&i, x, TSI_CONTINUE_LINKING);
|
||
|
||
x = build0 (FILTER_EXPR, integer_type_node);
|
||
x = build2 (MODIFY_EXPR, void_type_node, save_filt, x);
|
||
tsi_link_before (&i, x, TSI_CONTINUE_LINKING);
|
||
|
||
i = tsi_last (finally);
|
||
x = build0 (EXC_PTR_EXPR, ptr_type_node);
|
||
x = build2 (MODIFY_EXPR, void_type_node, x, save_eptr);
|
||
tsi_link_after (&i, x, TSI_CONTINUE_LINKING);
|
||
|
||
x = build0 (FILTER_EXPR, integer_type_node);
|
||
x = build2 (MODIFY_EXPR, void_type_node, x, save_filt);
|
||
tsi_link_after (&i, x, TSI_CONTINUE_LINKING);
|
||
|
||
x = build_resx (get_eh_region_number (tf->region));
|
||
tsi_link_after (&i, x, TSI_CONTINUE_LINKING);
|
||
}
|
||
|
||
/* Wrap the block with protect_cleanup_actions as the action. */
|
||
if (protect_cleanup_actions)
|
||
{
|
||
x = build2 (EH_FILTER_EXPR, void_type_node, NULL, NULL);
|
||
append_to_statement_list (protect_cleanup_actions, &EH_FILTER_FAILURE (x));
|
||
EH_FILTER_MUST_NOT_THROW (x) = 1;
|
||
finally = build2 (TRY_CATCH_EXPR, void_type_node, finally, x);
|
||
lower_eh_filter (outer_state, &finally);
|
||
}
|
||
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. */
|
||
|
||
i = tsi_last (TREE_OPERAND (*tf->top_p, 0));
|
||
|
||
if (tf->may_fallthru)
|
||
{
|
||
x = lower_try_finally_fallthru_label (tf);
|
||
x = build1 (GOTO_EXPR, void_type_node, x);
|
||
tsi_link_after (&i, x, TSI_CONTINUE_LINKING);
|
||
|
||
if (this_state)
|
||
maybe_record_in_goto_queue (this_state, x);
|
||
|
||
tf->may_fallthru = false;
|
||
}
|
||
|
||
x = build1 (LABEL_EXPR, void_type_node, tf->eh_label);
|
||
tsi_link_after (&i, x, TSI_CONTINUE_LINKING);
|
||
tsi_link_after (&i, finally, TSI_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 x, finally, lab, return_val;
|
||
struct goto_queue_node *q, *qe;
|
||
|
||
if (tf->may_throw)
|
||
lab = tf->eh_label;
|
||
else
|
||
lab = create_artificial_label ();
|
||
|
||
finally = TREE_OPERAND (*tf->top_p, 1);
|
||
*tf->top_p = TREE_OPERAND (*tf->top_p, 0);
|
||
|
||
x = build1 (LABEL_EXPR, void_type_node, lab);
|
||
append_to_statement_list (x, tf->top_p);
|
||
|
||
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);
|
||
|
||
replace_goto_queue (tf);
|
||
|
||
lower_eh_constructs_1 (state, &finally);
|
||
append_to_statement_list (finally, tf->top_p);
|
||
}
|
||
|
||
/* 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;
|
||
tree x, finally, finally_label;
|
||
|
||
finally = TREE_OPERAND (*tf->top_p, 1);
|
||
*tf->top_p = TREE_OPERAND (*tf->top_p, 0);
|
||
|
||
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 = build1 (LABEL_EXPR, void_type_node, tf->eh_label);
|
||
append_to_statement_list (x, tf->top_p);
|
||
|
||
append_to_statement_list (finally, tf->top_p);
|
||
|
||
x = build_resx (get_eh_region_number (tf->region));
|
||
|
||
append_to_statement_list (x, tf->top_p);
|
||
|
||
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. */
|
||
append_to_statement_list (finally, tf->top_p);
|
||
return;
|
||
}
|
||
|
||
finally_label = create_artificial_label ();
|
||
x = build1 (LABEL_EXPR, void_type_node, finally_label);
|
||
append_to_statement_list (x, tf->top_p);
|
||
|
||
append_to_statement_list (finally, tf->top_p);
|
||
|
||
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);
|
||
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;
|
||
}
|
||
}
|
||
|
||
append_to_statement_list (tf->goto_queue[0].cont_stmt, tf->top_p);
|
||
maybe_record_in_goto_queue (state, tf->goto_queue[0].cont_stmt);
|
||
}
|
||
|
||
/* 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)
|
||
{
|
||
tree finally, new_stmt;
|
||
tree x;
|
||
|
||
finally = TREE_OPERAND (*tf->top_p, 1);
|
||
*tf->top_p = TREE_OPERAND (*tf->top_p, 0);
|
||
|
||
new_stmt = NULL_TREE;
|
||
|
||
if (tf->may_fallthru)
|
||
{
|
||
x = lower_try_finally_dup_block (finally, state);
|
||
lower_eh_constructs_1 (state, &x);
|
||
append_to_statement_list (x, &new_stmt);
|
||
|
||
x = lower_try_finally_fallthru_label (tf);
|
||
x = build1 (GOTO_EXPR, void_type_node, x);
|
||
append_to_statement_list (x, &new_stmt);
|
||
}
|
||
|
||
if (tf->may_throw)
|
||
{
|
||
x = build1 (LABEL_EXPR, void_type_node, tf->eh_label);
|
||
append_to_statement_list (x, &new_stmt);
|
||
|
||
x = lower_try_finally_dup_block (finally, state);
|
||
lower_eh_constructs_1 (state, &x);
|
||
append_to_statement_list (x, &new_stmt);
|
||
|
||
x = build_resx (get_eh_region_number (tf->region));
|
||
append_to_statement_list (x, &new_stmt);
|
||
}
|
||
|
||
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);
|
||
|
||
x = build1 (LABEL_EXPR, void_type_node, lab);
|
||
append_to_statement_list (x, &new_stmt);
|
||
|
||
x = lower_try_finally_dup_block (finally, state);
|
||
lower_eh_constructs_1 (state, &x);
|
||
append_to_statement_list (x, &new_stmt);
|
||
|
||
append_to_statement_list (q->cont_stmt, &new_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);
|
||
}
|
||
|
||
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. */
|
||
append_to_statement_list (new_stmt, tf->top_p);
|
||
}
|
||
|
||
/* 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, finally_tmp, finally_label;
|
||
int return_index, eh_index, fallthru_index;
|
||
int nlabels, ndests, j, last_case_index;
|
||
tree case_label_vec, switch_stmt, last_case, switch_body;
|
||
tree x;
|
||
|
||
/* Mash the TRY block to the head of the chain. */
|
||
finally = TREE_OPERAND (*tf->top_p, 1);
|
||
*tf->top_p = TREE_OPERAND (*tf->top_p, 0);
|
||
|
||
/* 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 ();
|
||
|
||
case_label_vec = make_tree_vec (ndests);
|
||
switch_stmt = build3 (SWITCH_EXPR, integer_type_node, finally_tmp,
|
||
NULL_TREE, case_label_vec);
|
||
switch_body = NULL;
|
||
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 = build2 (MODIFY_EXPR, void_type_node, finally_tmp,
|
||
build_int_cst (NULL_TREE, fallthru_index));
|
||
append_to_statement_list (x, tf->top_p);
|
||
|
||
if (tf->may_throw)
|
||
{
|
||
x = build1 (GOTO_EXPR, void_type_node, finally_label);
|
||
append_to_statement_list (x, tf->top_p);
|
||
}
|
||
|
||
|
||
last_case = build3 (CASE_LABEL_EXPR, void_type_node,
|
||
build_int_cst (NULL_TREE, fallthru_index), NULL,
|
||
create_artificial_label ());
|
||
TREE_VEC_ELT (case_label_vec, last_case_index) = last_case;
|
||
last_case_index++;
|
||
|
||
x = build1 (LABEL_EXPR, void_type_node, CASE_LABEL (last_case));
|
||
append_to_statement_list (x, &switch_body);
|
||
|
||
x = lower_try_finally_fallthru_label (tf);
|
||
x = build1 (GOTO_EXPR, void_type_node, x);
|
||
append_to_statement_list (x, &switch_body);
|
||
}
|
||
|
||
if (tf->may_throw)
|
||
{
|
||
x = build1 (LABEL_EXPR, void_type_node, tf->eh_label);
|
||
append_to_statement_list (x, tf->top_p);
|
||
|
||
x = build2 (MODIFY_EXPR, void_type_node, finally_tmp,
|
||
build_int_cst (NULL_TREE, eh_index));
|
||
append_to_statement_list (x, tf->top_p);
|
||
|
||
last_case = build3 (CASE_LABEL_EXPR, void_type_node,
|
||
build_int_cst (NULL_TREE, eh_index), NULL,
|
||
create_artificial_label ());
|
||
TREE_VEC_ELT (case_label_vec, last_case_index) = last_case;
|
||
last_case_index++;
|
||
|
||
x = build1 (LABEL_EXPR, void_type_node, CASE_LABEL (last_case));
|
||
append_to_statement_list (x, &switch_body);
|
||
x = build_resx (get_eh_region_number (tf->region));
|
||
append_to_statement_list (x, &switch_body);
|
||
}
|
||
|
||
x = build1 (LABEL_EXPR, void_type_node, finally_label);
|
||
append_to_statement_list (x, tf->top_p);
|
||
|
||
append_to_statement_list (finally, tf->top_p);
|
||
|
||
/* Redirect each incoming goto edge. */
|
||
q = tf->goto_queue;
|
||
qe = q + tf->goto_queue_active;
|
||
j = last_case_index + tf->may_return;
|
||
for (; q < qe; ++q)
|
||
{
|
||
tree mod;
|
||
int switch_id, case_index;
|
||
|
||
if (q->index < 0)
|
||
{
|
||
mod = build2 (MODIFY_EXPR, void_type_node, finally_tmp,
|
||
build_int_cst (NULL_TREE, return_index));
|
||
do_return_redirection (q, finally_label, mod, &return_val);
|
||
switch_id = return_index;
|
||
}
|
||
else
|
||
{
|
||
mod = build2 (MODIFY_EXPR, void_type_node, finally_tmp,
|
||
build_int_cst (NULL_TREE, q->index));
|
||
do_goto_redirection (q, finally_label, mod);
|
||
switch_id = q->index;
|
||
}
|
||
|
||
case_index = j + q->index;
|
||
if (!TREE_VEC_ELT (case_label_vec, case_index))
|
||
TREE_VEC_ELT (case_label_vec, case_index)
|
||
= build3 (CASE_LABEL_EXPR, void_type_node,
|
||
build_int_cst (NULL_TREE, switch_id), NULL,
|
||
/* We store the cont_stmt in the
|
||
CASE_LABEL, 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. */
|
||
q->cont_stmt);
|
||
}
|
||
for (j = last_case_index; j < last_case_index + nlabels; j++)
|
||
{
|
||
tree label;
|
||
tree cont_stmt;
|
||
|
||
last_case = TREE_VEC_ELT (case_label_vec, j);
|
||
|
||
gcc_assert (last_case);
|
||
|
||
cont_stmt = CASE_LABEL (last_case);
|
||
|
||
label = create_artificial_label ();
|
||
CASE_LABEL (last_case) = label;
|
||
|
||
x = build1 (LABEL_EXPR, void_type_node, label);
|
||
append_to_statement_list (x, &switch_body);
|
||
append_to_statement_list (cont_stmt, &switch_body);
|
||
maybe_record_in_goto_queue (state, cont_stmt);
|
||
}
|
||
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);
|
||
|
||
/* Need to link switch_stmt after running replace_goto_queue due
|
||
to not wanting to process the same goto stmts twice. */
|
||
append_to_statement_list (switch_stmt, tf->top_p);
|
||
append_to_statement_list (switch_body, tf->top_p);
|
||
}
|
||
|
||
/* 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, tree finally)
|
||
{
|
||
int f_estimate, sw_estimate;
|
||
|
||
if (!optimize)
|
||
return false;
|
||
|
||
/* Finally estimate N times, plus N gotos. */
|
||
f_estimate = estimate_num_insns (finally);
|
||
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_size)
|
||
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 TRY_FINALLY_EXPR 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 void
|
||
lower_try_finally (struct leh_state *state, tree *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, &TREE_OPERAND (*tp, 0));
|
||
|
||
/* Determine if the try block is escaped through the bottom. */
|
||
this_tf.may_fallthru = block_may_fallthru (TREE_OPERAND (*tp, 0));
|
||
|
||
/* 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);
|
||
}
|
||
|
||
/* Sort the goto queue for efficient searching later. */
|
||
if (this_tf.goto_queue_active > 1)
|
||
qsort (this_tf.goto_queue, this_tf.goto_queue_active,
|
||
sizeof (struct goto_queue_node), goto_queue_cmp);
|
||
|
||
/* 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)
|
||
*tp = TREE_OPERAND (*tp, 0);
|
||
|
||
/* 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 (!block_may_fallthru (TREE_OPERAND (*tp, 1)))
|
||
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, TREE_OPERAND (*tp, 1)))
|
||
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)
|
||
{
|
||
tree x = build1 (LABEL_EXPR, void_type_node, this_tf.fallthru_label);
|
||
append_to_statement_list (x, tp);
|
||
}
|
||
|
||
VEC_free (tree, heap, this_tf.dest_array);
|
||
if (this_tf.goto_queue)
|
||
free (this_tf.goto_queue);
|
||
}
|
||
|
||
/* A subroutine of lower_eh_constructs_1. Lower a TRY_CATCH_EXPR with a
|
||
list of CATCH_EXPR nodes to a sequence of labels and blocks, plus the
|
||
exception region trees that record all the magic. */
|
||
|
||
static void
|
||
lower_catch (struct leh_state *state, tree *tp)
|
||
{
|
||
struct eh_region *try_region;
|
||
struct leh_state this_state;
|
||
tree_stmt_iterator i;
|
||
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, &TREE_OPERAND (*tp, 0));
|
||
|
||
if (!get_eh_region_may_contain_throw (try_region))
|
||
{
|
||
*tp = TREE_OPERAND (*tp, 0);
|
||
return;
|
||
}
|
||
|
||
out_label = NULL;
|
||
for (i = tsi_start (TREE_OPERAND (*tp, 1)); !tsi_end_p (i); )
|
||
{
|
||
struct eh_region *catch_region;
|
||
tree catch, x, eh_label;
|
||
|
||
catch = tsi_stmt (i);
|
||
catch_region = gen_eh_region_catch (try_region, CATCH_TYPES (catch));
|
||
|
||
this_state.cur_region = catch_region;
|
||
this_state.prev_try = state->prev_try;
|
||
lower_eh_constructs_1 (&this_state, &CATCH_BODY (catch));
|
||
|
||
eh_label = create_artificial_label ();
|
||
set_eh_region_tree_label (catch_region, eh_label);
|
||
|
||
x = build1 (LABEL_EXPR, void_type_node, eh_label);
|
||
tsi_link_before (&i, x, TSI_SAME_STMT);
|
||
|
||
if (block_may_fallthru (CATCH_BODY (catch)))
|
||
{
|
||
if (!out_label)
|
||
out_label = create_artificial_label ();
|
||
|
||
x = build1 (GOTO_EXPR, void_type_node, out_label);
|
||
append_to_statement_list (x, &CATCH_BODY (catch));
|
||
}
|
||
|
||
tsi_link_before (&i, CATCH_BODY (catch), TSI_SAME_STMT);
|
||
tsi_delink (&i);
|
||
}
|
||
|
||
frob_into_branch_around (tp, NULL, out_label);
|
||
}
|
||
|
||
/* A subroutine of lower_eh_constructs_1. Lower a TRY_CATCH_EXPR with a
|
||
EH_FILTER_EXPR to a sequence of labels and blocks, plus the exception
|
||
region trees that record all the magic. */
|
||
|
||
static void
|
||
lower_eh_filter (struct leh_state *state, tree *tp)
|
||
{
|
||
struct leh_state this_state;
|
||
struct eh_region *this_region;
|
||
tree inner = expr_first (TREE_OPERAND (*tp, 1));
|
||
tree eh_label;
|
||
|
||
if (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,
|
||
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 (EH_FILTER_MUST_NOT_THROW (inner))
|
||
this_state.prev_try = NULL;
|
||
|
||
lower_eh_constructs_1 (&this_state, &TREE_OPERAND (*tp, 0));
|
||
|
||
if (!get_eh_region_may_contain_throw (this_region))
|
||
{
|
||
*tp = TREE_OPERAND (*tp, 0);
|
||
return;
|
||
}
|
||
|
||
lower_eh_constructs_1 (state, &EH_FILTER_FAILURE (inner));
|
||
TREE_OPERAND (*tp, 1) = EH_FILTER_FAILURE (inner);
|
||
|
||
eh_label = create_artificial_label ();
|
||
set_eh_region_tree_label (this_region, eh_label);
|
||
|
||
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 void
|
||
lower_cleanup (struct leh_state *state, tree *tp)
|
||
{
|
||
struct leh_state this_state;
|
||
struct eh_region *this_region;
|
||
struct leh_tf_state fake_tf;
|
||
|
||
/* If not using eh, then exception-only cleanups are no-ops. */
|
||
if (!flag_exceptions)
|
||
{
|
||
*tp = TREE_OPERAND (*tp, 0);
|
||
lower_eh_constructs_1 (state, tp);
|
||
return;
|
||
}
|
||
|
||
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, &TREE_OPERAND (*tp, 0));
|
||
|
||
if (!get_eh_region_may_contain_throw (this_region))
|
||
{
|
||
*tp = TREE_OPERAND (*tp, 0);
|
||
return;
|
||
}
|
||
|
||
/* 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 = block_may_fallthru (TREE_OPERAND (*tp, 0));
|
||
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, &TREE_OPERAND (*tp, 1));
|
||
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. */
|
||
|
||
*tp = TREE_OPERAND (*tp, 0);
|
||
if (fake_tf.fallthru_label)
|
||
{
|
||
tree x = build1 (LABEL_EXPR, void_type_node, fake_tf.fallthru_label);
|
||
append_to_statement_list (x, tp);
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Main loop for lowering eh constructs. */
|
||
|
||
static void
|
||
lower_eh_constructs_1 (struct leh_state *state, tree *tp)
|
||
{
|
||
tree_stmt_iterator i;
|
||
tree t = *tp;
|
||
|
||
switch (TREE_CODE (t))
|
||
{
|
||
case COND_EXPR:
|
||
lower_eh_constructs_1 (state, &COND_EXPR_THEN (t));
|
||
lower_eh_constructs_1 (state, &COND_EXPR_ELSE (t));
|
||
break;
|
||
|
||
case CALL_EXPR:
|
||
/* Look for things that can throw exceptions, and record them. */
|
||
if (state->cur_region && tree_could_throw_p (t))
|
||
{
|
||
record_stmt_eh_region (state->cur_region, t);
|
||
note_eh_region_may_contain_throw (state->cur_region);
|
||
}
|
||
break;
|
||
|
||
case MODIFY_EXPR:
|
||
/* Look for things that can throw exceptions, and record them. */
|
||
if (state->cur_region && tree_could_throw_p (t))
|
||
{
|
||
record_stmt_eh_region (state->cur_region, t);
|
||
note_eh_region_may_contain_throw (state->cur_region);
|
||
}
|
||
break;
|
||
|
||
case GOTO_EXPR:
|
||
case RETURN_EXPR:
|
||
maybe_record_in_goto_queue (state, t);
|
||
break;
|
||
case SWITCH_EXPR:
|
||
verify_norecord_switch_expr (state, t);
|
||
break;
|
||
|
||
case TRY_FINALLY_EXPR:
|
||
lower_try_finally (state, tp);
|
||
break;
|
||
|
||
case TRY_CATCH_EXPR:
|
||
i = tsi_start (TREE_OPERAND (t, 1));
|
||
switch (TREE_CODE (tsi_stmt (i)))
|
||
{
|
||
case CATCH_EXPR:
|
||
lower_catch (state, tp);
|
||
break;
|
||
case EH_FILTER_EXPR:
|
||
lower_eh_filter (state, tp);
|
||
break;
|
||
default:
|
||
lower_cleanup (state, tp);
|
||
break;
|
||
}
|
||
break;
|
||
|
||
case STATEMENT_LIST:
|
||
for (i = tsi_start (t); !tsi_end_p (i); )
|
||
{
|
||
lower_eh_constructs_1 (state, tsi_stmt_ptr (i));
|
||
t = tsi_stmt (i);
|
||
if (TREE_CODE (t) == STATEMENT_LIST)
|
||
{
|
||
tsi_link_before (&i, t, TSI_SAME_STMT);
|
||
tsi_delink (&i);
|
||
}
|
||
else
|
||
tsi_next (&i);
|
||
}
|
||
break;
|
||
|
||
default:
|
||
/* A type, a decl, or some kind of statement that we're not
|
||
interested in. Don't walk them. */
|
||
break;
|
||
}
|
||
}
|
||
|
||
static unsigned int
|
||
lower_eh_constructs (void)
|
||
{
|
||
struct leh_state null_state;
|
||
tree *tp = &DECL_SAVED_TREE (current_function_decl);
|
||
|
||
finally_tree = htab_create (31, struct_ptr_hash, struct_ptr_eq, free);
|
||
|
||
collect_finally_tree (*tp, NULL);
|
||
|
||
memset (&null_state, 0, sizeof (null_state));
|
||
lower_eh_constructs_1 (&null_state, tp);
|
||
|
||
htab_delete (finally_tree);
|
||
|
||
collect_eh_region_array ();
|
||
return 0;
|
||
}
|
||
|
||
struct tree_opt_pass pass_lower_eh =
|
||
{
|
||
"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 */
|
||
0 /* letter */
|
||
};
|
||
|
||
|
||
/* Construct EH edges for STMT. */
|
||
|
||
static void
|
||
make_eh_edge (struct eh_region *region, void *data)
|
||
{
|
||
tree stmt, lab;
|
||
basic_block src, dst;
|
||
|
||
stmt = (tree) data;
|
||
lab = get_eh_region_tree_label (region);
|
||
|
||
src = bb_for_stmt (stmt);
|
||
dst = label_to_block (lab);
|
||
|
||
make_edge (src, dst, EDGE_ABNORMAL | EDGE_EH);
|
||
}
|
||
|
||
void
|
||
make_eh_edges (tree stmt)
|
||
{
|
||
int region_nr;
|
||
bool is_resx;
|
||
|
||
if (TREE_CODE (stmt) == RESX_EXPR)
|
||
{
|
||
region_nr = TREE_INT_CST_LOW (TREE_OPERAND (stmt, 0));
|
||
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)
|
||
{
|
||
tree stmt, lab;
|
||
basic_block src, dst;
|
||
edge e;
|
||
|
||
stmt = (tree) data;
|
||
lab = get_eh_region_tree_label (region);
|
||
|
||
src = bb_for_stmt (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 last stmt has precisely the edges
|
||
make_eh_edges would create. */
|
||
bool
|
||
verify_eh_edges (tree stmt)
|
||
{
|
||
int region_nr;
|
||
bool is_resx;
|
||
basic_block bb = bb_for_stmt (stmt);
|
||
edge_iterator ei;
|
||
edge e;
|
||
|
||
FOR_EACH_EDGE (e, ei, bb->succs)
|
||
gcc_assert (!e->aux);
|
||
mark_eh_edge_found_error = false;
|
||
if (TREE_CODE (stmt) == RESX_EXPR)
|
||
{
|
||
region_nr = TREE_INT_CST_LOW (TREE_OPERAND (stmt, 0));
|
||
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 (!tree_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;
|
||
}
|
||
|
||
|
||
/* Return true if the 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 = TREE_CODE (expr);
|
||
bool honor_nans = false;
|
||
bool honor_snans = false;
|
||
bool fp_operation = false;
|
||
bool honor_trapv = false;
|
||
tree t, base;
|
||
|
||
if (TREE_CODE_CLASS (code) == tcc_comparison
|
||
|| TREE_CODE_CLASS (code) == tcc_unary
|
||
|| TREE_CODE_CLASS (code) == tcc_binary)
|
||
{
|
||
t = TREE_TYPE (expr);
|
||
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;
|
||
}
|
||
|
||
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 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;
|
||
t = TREE_OPERAND (expr, 1);
|
||
if (!TREE_CONSTANT (t) || integer_zerop (t))
|
||
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:
|
||
case FIX_CEIL_EXPR:
|
||
case FIX_FLOOR_EXPR:
|
||
case FIX_ROUND_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;
|
||
|
||
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:
|
||
/* Any floating arithmetic may trap. */
|
||
if (fp_operation && flag_trapping_math)
|
||
return true;
|
||
return false;
|
||
}
|
||
}
|
||
|
||
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;
|
||
}
|
||
|
||
bool
|
||
tree_can_throw_internal (tree stmt)
|
||
{
|
||
int region_nr;
|
||
bool is_resx = false;
|
||
|
||
if (TREE_CODE (stmt) == RESX_EXPR)
|
||
region_nr = TREE_INT_CST_LOW (TREE_OPERAND (stmt, 0)), 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);
|
||
}
|
||
|
||
bool
|
||
tree_can_throw_external (tree stmt)
|
||
{
|
||
int region_nr;
|
||
bool is_resx = false;
|
||
|
||
if (TREE_CODE (stmt) == RESX_EXPR)
|
||
region_nr = TREE_INT_CST_LOW (TREE_OPERAND (stmt, 0)), is_resx = true;
|
||
else
|
||
region_nr = lookup_stmt_eh_region (stmt);
|
||
if (region_nr < 0)
|
||
return tree_could_throw_p (stmt);
|
||
else
|
||
return can_throw_external_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 (tree old_stmt, tree new_stmt)
|
||
{
|
||
int region_nr = lookup_stmt_eh_region (old_stmt);
|
||
|
||
if (region_nr >= 0)
|
||
{
|
||
bool new_stmt_could_throw = tree_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;
|
||
}
|
||
|
||
#ifdef ENABLE_CHECKING
|
||
static int
|
||
verify_eh_throw_stmt_node (void **slot, void *data ATTRIBUTE_UNUSED)
|
||
{
|
||
struct throw_stmt_node *node = (struct throw_stmt_node *)*slot;
|
||
|
||
gcc_assert (node->stmt->common.ann == NULL);
|
||
return 1;
|
||
}
|
||
|
||
void
|
||
verify_eh_throw_table_statements (void)
|
||
{
|
||
if (!get_eh_throw_stmt_table (cfun))
|
||
return;
|
||
htab_traverse (get_eh_throw_stmt_table (cfun),
|
||
verify_eh_throw_stmt_node,
|
||
NULL);
|
||
}
|
||
|
||
#endif
|