3309 lines
90 KiB
C
3309 lines
90 KiB
C
/* Exception handling semantics and decomposition for trees.
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Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009
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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 3, 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 COPYING3. If not see
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<http://www.gnu.org/licenses/>. */
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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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#include "gimple.h"
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/* In some instances a tree and a gimple need to be stored in a same table,
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i.e. in hash tables. This is a structure to do this. */
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typedef union {tree *tp; tree t; gimple g;} treemple;
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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_d *region, gimple 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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/* Add statement T in function IFUN to EH region NUM. */
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void
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add_stmt_to_eh_region_fn (struct function *ifun, gimple 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 (gimple_code (t) != GIMPLE_RESX);
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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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}
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/* Add statement T in the current function (cfun) to EH region number
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NUM. */
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void
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add_stmt_to_eh_region (gimple 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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/* Remove statement T in function IFUN from the EH region holding it. */
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bool
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remove_stmt_from_eh_region_fn (struct function *ifun, gimple 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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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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/* Remove statement T in the current function (cfun) from the EH
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region holding it. */
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bool
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remove_stmt_from_eh_region (gimple 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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/* Determine if statement T is inside an EH region in function IFUN.
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Return the EH region number if found, return -2 if IFUN does not
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have an EH table and -1 if T could not be found in IFUN's EH region
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table. */
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int
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lookup_stmt_eh_region_fn (struct function *ifun, gimple 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), &n);
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return (p ? p->region_nr : -1);
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}
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/* Determine if statement T is inside an EH region in the current
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function (cfun). Return the EH region number if found, return -2
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if cfun does not have an EH table and -1 if T could not be found in
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cfun's EH region table. */
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int
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lookup_stmt_eh_region (gimple 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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/* Determine if expression T is inside an EH region in the current
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function (cfun). Return the EH region number if found, return -2
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if IFUN does not have an EH table and -1 if T could not be found in
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IFUN's EH region table. */
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int
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lookup_expr_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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if (!get_eh_throw_stmt_table (cfun))
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return -2;
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if (t && EXPR_P (t))
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{
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tree_ann_common_t ann = tree_common_ann (t);
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if (ann)
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return (int) ann->rn;
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}
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return -1;
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}
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/* First pass of EH node decomposition. Build up a tree of GIMPLE_TRY_FINALLY
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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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/* When storing a GIMPLE_TRY, we have to record a gimple. However
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when deciding whether a GOTO to a certain LABEL_DECL (which is a
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tree) leaves the TRY block, its necessary to record a tree in
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this field. Thus a treemple is used. */
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treemple child;
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gimple 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 (treemple child, gimple 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 (gimple stmt, gimple region);
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/* Go through the gimple sequence. Works with collect_finally_tree to
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record all GIMPLE_LABEL and GIMPLE_TRY statements. */
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static void
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collect_finally_tree_1 (gimple_seq seq, gimple region)
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{
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gimple_stmt_iterator gsi;
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for (gsi = gsi_start (seq); !gsi_end_p (gsi); gsi_next (&gsi))
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collect_finally_tree (gsi_stmt (gsi), region);
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}
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static void
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collect_finally_tree (gimple stmt, gimple region)
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{
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treemple temp;
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switch (gimple_code (stmt))
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{
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case GIMPLE_LABEL:
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temp.t = gimple_label_label (stmt);
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record_in_finally_tree (temp, region);
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break;
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case GIMPLE_TRY:
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if (gimple_try_kind (stmt) == GIMPLE_TRY_FINALLY)
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{
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temp.g = stmt;
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record_in_finally_tree (temp, region);
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collect_finally_tree_1 (gimple_try_eval (stmt), stmt);
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collect_finally_tree_1 (gimple_try_cleanup (stmt), region);
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}
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else if (gimple_try_kind (stmt) == GIMPLE_TRY_CATCH)
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{
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collect_finally_tree_1 (gimple_try_eval (stmt), region);
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collect_finally_tree_1 (gimple_try_cleanup (stmt), region);
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}
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break;
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case GIMPLE_CATCH:
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collect_finally_tree_1 (gimple_catch_handler (stmt), region);
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break;
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case GIMPLE_EH_FILTER:
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collect_finally_tree_1 (gimple_eh_filter_failure (stmt), region);
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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 (treemple start, gimple 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.g = p->parent;
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}
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while (start.g != target);
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return false;
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}
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/* Second pass of EH node decomposition. Actually transform the GIMPLE_TRY
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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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/* The GOTO_QUEUE is is an array of GIMPLE_GOTO and GIMPLE_RETURN
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statements that are seen to escape this GIMPLE_TRY_FINALLY node.
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The idea is to record a gimple statement for everything except for
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the conditionals, which get their labels recorded. Since labels are
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of type 'tree', we need this node to store both gimple and tree
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objects. REPL_STMT is the sequence used to replace the goto/return
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statement. CONT_STMT is used to store the statement that allows
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the return/goto to jump to the original destination. */
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struct goto_queue_node
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{
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treemple stmt;
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gimple_seq repl_stmt;
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gimple cont_stmt;
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int index;
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/* This is used when index >= 0 to indicate that stmt is a label (as
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opposed to a goto stmt). */
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int is_label;
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};
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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_d *cur_region;
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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 GIMPLE_TRY_FINALLY node under discussion. The
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try_finally_expr is the original GIMPLE_TRY_FINALLY. We need to retain
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this so that outside_finally_tree can reliably reference the tree used
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in the collect_finally_tree data structures. */
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gimple try_finally_expr;
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gimple top_p;
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/* While lowering a top_p usually it is expanded into multiple statements,
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thus we need the following field to store them. */
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gimple_seq top_p_seq;
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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_d *region;
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/* The goto queue. */
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struct goto_queue_node *goto_queue;
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size_t goto_queue_size;
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size_t goto_queue_active;
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/* Pointer map to help in searching goto_queue when it is large. */
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struct pointer_map_t *goto_queue_map;
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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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||
|
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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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||
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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. */
|
||
bool may_fallthru;
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||
|
||
/* True if any entry in goto_queue is a GIMPLE_RETURN. */
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||
bool may_return;
|
||
|
||
/* True if the finally block can receive an exception edge.
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||
Cleared if the exception case is handled by code duplication. */
|
||
bool may_throw;
|
||
};
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||
|
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static gimple_seq lower_eh_filter (struct leh_state *, gimple);
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||
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/* 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;
|
||
location_t loc = gimple_location (gsi_stmt (*gsi));
|
||
|
||
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 (loc);
|
||
/* 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;
|
||
location_t loc = gimple_location (tp);
|
||
|
||
cleanup = gimple_try_cleanup (tp);
|
||
result = gimple_try_eval (tp);
|
||
|
||
if (gimple_seq_may_fallthru (result))
|
||
{
|
||
if (!over)
|
||
over = create_artificial_label (loc);
|
||
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 (gimple_location (tf->try_finally_expr));
|
||
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 (gimple_location (tf->try_finally_expr));
|
||
|
||
/* 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;
|
||
location_t loc = gimple_location (tf->try_finally_expr);
|
||
|
||
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 (loc);
|
||
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;
|
||
location_t tf_loc = gimple_location (tf->try_finally_expr);
|
||
|
||
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 (tf_loc);
|
||
|
||
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;
|
||
/* The location of the TRY_FINALLY stmt. */
|
||
location_t tf_loc = gimple_location (tf->try_finally_expr);
|
||
/* The location of the finally block. */
|
||
location_t finally_loc;
|
||
|
||
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);
|
||
|
||
/* The location of the finally is either the last stmt in the finally
|
||
block or the location of the TRY_FINALLY itself. */
|
||
finally_loc = gimple_seq_last_stmt (tf->top_p_seq) != NULL ?
|
||
gimple_location (gimple_seq_last_stmt (tf->top_p_seq))
|
||
: tf_loc;
|
||
|
||
/* 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 (finally_loc);
|
||
|
||
/* 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 (tf_loc));
|
||
VEC_quick_push (tree, case_label_vec, last_case);
|
||
last_case_index++;
|
||
|
||
x = gimple_build_label (CASE_LABEL (last_case));
|
||
gimple_seq_add_stmt (&switch_body, x);
|
||
|
||
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 (tf_loc));
|
||
VEC_quick_push (tree, case_label_vec, last_case);
|
||
last_case_index++;
|
||
|
||
x = gimple_build_label (CASE_LABEL (last_case));
|
||
gimple_seq_add_stmt (&switch_body, x);
|
||
x = gimple_build_resx (get_eh_region_number (tf->region));
|
||
gimple_seq_add_stmt (&switch_body, x);
|
||
}
|
||
|
||
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 (tf_loc);
|
||
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);
|
||
gimple_set_location (switch_stmt, finally_loc);
|
||
|
||
/* 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;
|
||
location_t tf_loc = gimple_location (tp);
|
||
|
||
/* 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);
|
||
else
|
||
this_tf.region = NULL;
|
||
|
||
this_state.cur_region = this_tf.region;
|
||
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 (tf_loc);
|
||
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_d *try_region;
|
||
struct leh_state this_state;
|
||
gimple_stmt_iterator gsi;
|
||
tree out_label;
|
||
location_t try_catch_loc = gimple_location (tp);
|
||
|
||
try_region = gen_eh_region_try (state->cur_region);
|
||
this_state.cur_region = try_region;
|
||
this_state.tf = state->tf;
|
||
|
||
lower_eh_constructs_1 (&this_state, gimple_try_eval (tp));
|
||
|
||
if (!get_eh_region_may_contain_throw (try_region))
|
||
{
|
||
return gimple_try_eval (tp);
|
||
}
|
||
|
||
out_label = NULL;
|
||
for (gsi = gsi_start (gimple_try_cleanup (tp)); !gsi_end_p (gsi); )
|
||
{
|
||
struct eh_region_d *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;
|
||
lower_eh_constructs_1 (&this_state, gimple_catch_handler (gcatch));
|
||
|
||
eh_label = create_artificial_label (try_catch_loc);
|
||
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 (try_catch_loc);
|
||
|
||
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_d *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;
|
||
|
||
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 (gimple_location (inner));
|
||
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_d *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);
|
||
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 = fake_tf.try_finally_expr = 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 (gimple_location (tp));
|
||
set_eh_region_tree_label (this_region, fake_tf.eh_label);
|
||
|
||
honor_protect_cleanup_actions (state, NULL, &fake_tf);
|
||
|
||
if (fake_tf.may_throw)
|
||
{
|
||
/* 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:
|
||
/* If the stmt can throw use a new temporary for the assignment
|
||
to a LHS. This makes sure the old value of the LHS is
|
||
available on the EH edge. */
|
||
if (stmt_could_throw_p (stmt)
|
||
&& gimple_has_lhs (stmt)
|
||
&& !tree_could_throw_p (gimple_get_lhs (stmt))
|
||
&& is_gimple_reg_type (TREE_TYPE (gimple_get_lhs (stmt))))
|
||
{
|
||
tree lhs = gimple_get_lhs (stmt);
|
||
tree tmp = create_tmp_var (TREE_TYPE (lhs), NULL);
|
||
gimple s = gimple_build_assign (lhs, tmp);
|
||
gimple_set_location (s, gimple_location (stmt));
|
||
gimple_set_block (s, gimple_block (stmt));
|
||
gimple_set_lhs (stmt, tmp);
|
||
if (TREE_CODE (TREE_TYPE (tmp)) == COMPLEX_TYPE
|
||
|| TREE_CODE (TREE_TYPE (tmp)) == VECTOR_TYPE)
|
||
DECL_GIMPLE_REG_P (tmp) = 1;
|
||
gsi_insert_after (gsi, s, GSI_SAME_STMT);
|
||
}
|
||
/* 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 */
|
||
}
|
||
};
|
||
|
||
|
||
/* Construct EH edges for STMT. */
|
||
|
||
static void
|
||
make_eh_edge (struct eh_region_d *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_EH);
|
||
}
|
||
|
||
/* See if STMT is call that might be inlined. */
|
||
|
||
static bool
|
||
inlinable_call_p (gimple stmt)
|
||
{
|
||
tree decl;
|
||
if (gimple_code (stmt) != GIMPLE_CALL)
|
||
return false;
|
||
if (cfun->after_inlining)
|
||
return false;
|
||
/* Indirect calls can be propagated to direct call
|
||
and inlined. */
|
||
decl = gimple_call_fndecl (stmt);
|
||
if (!decl)
|
||
return true;
|
||
if (cgraph_function_flags_ready
|
||
&& cgraph_function_body_availability (cgraph_node (decl))
|
||
< AVAIL_OVERWRITABLE)
|
||
return false;
|
||
return !DECL_UNINLINABLE (decl);
|
||
}
|
||
|
||
void
|
||
make_eh_edges (gimple stmt)
|
||
{
|
||
int region_nr;
|
||
bool is_resx;
|
||
bool inlinable = false;
|
||
basic_block bb;
|
||
|
||
if (gimple_code (stmt) == GIMPLE_RESX)
|
||
{
|
||
region_nr = gimple_resx_region (stmt);
|
||
is_resx = true;
|
||
}
|
||
else
|
||
{
|
||
region_nr = lookup_stmt_eh_region (stmt);
|
||
if (region_nr < 0)
|
||
return;
|
||
is_resx = false;
|
||
inlinable = inlinable_call_p (stmt);
|
||
}
|
||
|
||
foreach_reachable_handler (region_nr, is_resx, inlinable, make_eh_edge, stmt);
|
||
|
||
/* Make CFG profile more consistent assuming that exception will resume to first
|
||
available EH handler. In practice this makes little difference, but we get
|
||
fewer consistency errors in the dumps. */
|
||
bb = gimple_bb (stmt);
|
||
if (is_resx && EDGE_COUNT (bb->succs))
|
||
EDGE_SUCC (bb, 0)->probability = REG_BR_PROB_BASE;
|
||
}
|
||
|
||
/* Redirect EH edge E to NEW_BB. */
|
||
|
||
edge
|
||
redirect_eh_edge (edge e, basic_block new_bb)
|
||
{
|
||
gimple stmt = gsi_stmt (gsi_last_bb (e->src));
|
||
int region_nr, new_region_nr;
|
||
bool is_resx;
|
||
bool inlinable = false;
|
||
tree label = gimple_block_label (new_bb);
|
||
struct eh_region_d *r;
|
||
|
||
if (gimple_code (stmt) == GIMPLE_RESX)
|
||
{
|
||
region_nr = gimple_resx_region (stmt);
|
||
is_resx = true;
|
||
}
|
||
else
|
||
{
|
||
region_nr = lookup_stmt_eh_region (stmt);
|
||
gcc_assert (region_nr >= 0);
|
||
is_resx = false;
|
||
inlinable = inlinable_call_p (stmt);
|
||
}
|
||
|
||
if (dump_file && (dump_flags & TDF_DETAILS))
|
||
fprintf (dump_file, "Redirecting EH edge %i->%i to %i, region %i, resx %i\n",
|
||
e->src->index, e->dest->index, new_bb->index, region_nr, is_resx);
|
||
r = redirect_eh_edge_to_label (e, label, is_resx, inlinable, region_nr);
|
||
new_region_nr = get_eh_region_number (r);
|
||
if (new_region_nr != region_nr)
|
||
{
|
||
if (is_resx)
|
||
gimple_resx_set_region (stmt, new_region_nr);
|
||
else
|
||
{
|
||
remove_stmt_from_eh_region (stmt);
|
||
add_stmt_to_eh_region (stmt, new_region_nr);
|
||
}
|
||
}
|
||
e = ssa_redirect_edge (e, new_bb);
|
||
return e;
|
||
}
|
||
|
||
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_d *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;
|
||
bool inlinable = false;
|
||
|
||
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;
|
||
}
|
||
inlinable = inlinable_call_p (stmt);
|
||
is_resx = false;
|
||
}
|
||
|
||
foreach_reachable_handler (region_nr, is_resx, inlinable, 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;
|
||
}
|
||
|
||
|
||
/* 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))
|
||
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 not caught within
|
||
the current function (CFUN). */
|
||
|
||
bool
|
||
stmt_can_throw_external (gimple stmt)
|
||
{
|
||
int region_nr;
|
||
bool is_resx = false;
|
||
bool inlinable_call = false;
|
||
|
||
if (!stmt_could_throw_p (stmt))
|
||
return false;
|
||
|
||
if (gimple_code (stmt) == GIMPLE_RESX)
|
||
{
|
||
region_nr = gimple_resx_region (stmt);
|
||
is_resx = true;
|
||
}
|
||
else
|
||
region_nr = lookup_stmt_eh_region (stmt);
|
||
|
||
if (region_nr < 0)
|
||
return true;
|
||
|
||
return can_throw_external_1 (region_nr, is_resx, inlinable_call);
|
||
}
|
||
|
||
/* 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;
|
||
bool inlinable_call = false;
|
||
|
||
if (gimple_code (stmt) == GIMPLE_RESX)
|
||
{
|
||
region_nr = gimple_resx_region (stmt);
|
||
is_resx = true;
|
||
}
|
||
else
|
||
{
|
||
region_nr = lookup_stmt_eh_region (stmt);
|
||
inlinable_call = inlinable_call_p (stmt);
|
||
}
|
||
|
||
if (region_nr < 0)
|
||
return false;
|
||
|
||
return can_throw_internal_1 (region_nr, is_resx, inlinable_call);
|
||
}
|
||
|
||
|
||
/* 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;
|
||
}
|
||
|
||
/* 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 */
|
||
}
|
||
};
|
||
|
||
/* Walk statements, see what regions are really references and remove unreachable ones. */
|
||
|
||
static void
|
||
tree_remove_unreachable_handlers (void)
|
||
{
|
||
sbitmap reachable, contains_stmt;
|
||
VEC(int,heap) * label_to_region;
|
||
basic_block bb;
|
||
|
||
label_to_region = label_to_region_map ();
|
||
reachable = sbitmap_alloc (num_eh_regions ());
|
||
sbitmap_zero (reachable);
|
||
contains_stmt = sbitmap_alloc (num_eh_regions ());
|
||
sbitmap_zero (contains_stmt);
|
||
|
||
FOR_EACH_BB (bb)
|
||
{
|
||
gimple_stmt_iterator gsi;
|
||
int region;
|
||
bool has_eh_preds = bb_has_eh_pred (bb);
|
||
|
||
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
|
||
{
|
||
gimple stmt = gsi_stmt (gsi);
|
||
|
||
if (gimple_code (stmt) == GIMPLE_LABEL && has_eh_preds)
|
||
{
|
||
int uid = LABEL_DECL_UID (gimple_label_label (stmt));
|
||
int region;
|
||
|
||
for (region = VEC_index (int, label_to_region, uid);
|
||
region; region = get_next_region_sharing_label (region))
|
||
SET_BIT (reachable, region);
|
||
}
|
||
if (gimple_code (stmt) == GIMPLE_RESX)
|
||
SET_BIT (reachable,
|
||
VEC_index (eh_region, cfun->eh->region_array,
|
||
gimple_resx_region (stmt))->region_number);
|
||
if ((region = lookup_stmt_eh_region (stmt)) >= 0)
|
||
SET_BIT (contains_stmt, region);
|
||
}
|
||
}
|
||
|
||
if (dump_file)
|
||
{
|
||
fprintf (dump_file, "Before removal of unreachable regions:\n");
|
||
dump_eh_tree (dump_file, cfun);
|
||
fprintf (dump_file, "Reachable regions: ");
|
||
dump_sbitmap_file (dump_file, reachable);
|
||
fprintf (dump_file, "Regions containing insns: ");
|
||
dump_sbitmap_file (dump_file, contains_stmt);
|
||
}
|
||
|
||
remove_unreachable_regions (reachable, contains_stmt);
|
||
sbitmap_free (reachable);
|
||
sbitmap_free (contains_stmt);
|
||
VEC_free (int, heap, label_to_region);
|
||
if (dump_file)
|
||
{
|
||
fprintf (dump_file, "\n\nAfter removal of unreachable regions:\n");
|
||
dump_eh_tree (dump_file, cfun);
|
||
fprintf (dump_file, "\n\n");
|
||
}
|
||
}
|
||
|
||
/* Pattern match emtpy EH receiver looking like:
|
||
|
||
save_filt.6352_662 = [filter_expr] <<<filter object>>>;
|
||
save_eptr.6351_663 = [exc_ptr_expr] <<<exception object>>>;
|
||
<<<exception object>>> = save_eptr.6351_663;
|
||
<<<filter object>>> = save_filt.6352_662;
|
||
resx 1
|
||
|
||
And various minor variants after DCE or copy propagation.
|
||
*/
|
||
|
||
static int
|
||
tree_empty_eh_handler_p (basic_block bb)
|
||
{
|
||
gimple_stmt_iterator gsi;
|
||
int region;
|
||
edge_iterator ei;
|
||
edge e;
|
||
use_operand_p imm_use;
|
||
gimple use_stmt;
|
||
bool found = false;
|
||
|
||
gsi = gsi_last_bb (bb);
|
||
|
||
/* RESX */
|
||
if (gsi_end_p (gsi))
|
||
return 0;
|
||
if (gimple_code (gsi_stmt (gsi)) != GIMPLE_RESX)
|
||
return 0;
|
||
region = gimple_resx_region (gsi_stmt (gsi));
|
||
|
||
/* filter_object set. */
|
||
gsi_prev (&gsi);
|
||
if (gsi_end_p (gsi))
|
||
return 0;
|
||
if (gimple_code (gsi_stmt (gsi)) == GIMPLE_ASSIGN)
|
||
{
|
||
tree filter_tmp;
|
||
tree exc_ptr_tmp;
|
||
|
||
if (TREE_CODE (gimple_assign_lhs (gsi_stmt (gsi))) != FILTER_EXPR)
|
||
return 0;
|
||
filter_tmp = gimple_assign_rhs1 (gsi_stmt (gsi));
|
||
|
||
/* filter_object set. */
|
||
gsi_prev (&gsi);
|
||
if (gsi_end_p (gsi))
|
||
return 0;
|
||
if (gimple_code (gsi_stmt (gsi)) != GIMPLE_ASSIGN)
|
||
return 0;
|
||
if (TREE_CODE (gimple_assign_lhs (gsi_stmt (gsi))) != EXC_PTR_EXPR)
|
||
return 0;
|
||
exc_ptr_tmp = gimple_assign_rhs1 (gsi_stmt (gsi));
|
||
|
||
/* exc_ptr get. */
|
||
if (TREE_CODE (exc_ptr_tmp) != EXC_PTR_EXPR)
|
||
{
|
||
gsi_prev (&gsi);
|
||
if (gsi_end_p (gsi))
|
||
return 0;
|
||
if (gimple_code (gsi_stmt (gsi)) != GIMPLE_ASSIGN)
|
||
return 0;
|
||
if (TREE_CODE (gimple_assign_rhs1 (gsi_stmt (gsi))) != EXC_PTR_EXPR)
|
||
return 0;
|
||
if (exc_ptr_tmp != gimple_assign_lhs (gsi_stmt (gsi)))
|
||
return 0;
|
||
if (!single_imm_use (exc_ptr_tmp, &imm_use, &use_stmt))
|
||
return 0;
|
||
}
|
||
|
||
/* filter_object get. */
|
||
if (TREE_CODE (filter_tmp) != FILTER_EXPR)
|
||
{
|
||
gsi_prev (&gsi);
|
||
if (gsi_end_p (gsi))
|
||
return 0;
|
||
if (gimple_code (gsi_stmt (gsi)) != GIMPLE_ASSIGN)
|
||
return 0;
|
||
if (TREE_CODE (gimple_assign_rhs1 (gsi_stmt (gsi))) != FILTER_EXPR)
|
||
return 0;
|
||
if (filter_tmp != gimple_assign_lhs (gsi_stmt (gsi)))
|
||
return 0;
|
||
if (!single_imm_use (filter_tmp, &imm_use, &use_stmt))
|
||
return 0;
|
||
}
|
||
|
||
/* label. */
|
||
gsi_prev (&gsi);
|
||
if (gsi_end_p (gsi))
|
||
return 0;
|
||
}
|
||
if (gimple_code (gsi_stmt (gsi)) != GIMPLE_LABEL)
|
||
return 0;
|
||
|
||
/* Be sure that there is at least on EH region reaching the block directly.
|
||
After EH edge redirection, it is possible that block is reached by one handler
|
||
but resumed by different. */
|
||
FOR_EACH_EDGE (e, ei, bb->preds)
|
||
if ((e->flags & EDGE_EH))
|
||
found = true;
|
||
if (found)
|
||
return region;
|
||
return 0;
|
||
}
|
||
|
||
/* Return true if it is possible to remove basic block BB and propagate
|
||
through PHIs.
|
||
|
||
This means that every PHI in BB has all uses such that they are PHIs
|
||
of basic blocks reachable througt BB and they appears only in use
|
||
reachable by the edge from BB to the block contianing the use.
|
||
|
||
This is same as in merge-phi code, but in slightly more general setting
|
||
because BB can have multiple successors. */
|
||
|
||
static bool
|
||
all_phis_safe_to_merge (basic_block bb)
|
||
{
|
||
gimple_stmt_iterator si;
|
||
bool ok = true;
|
||
|
||
for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
|
||
{
|
||
gimple phi = gsi_stmt (si);
|
||
tree result = gimple_phi_result (phi);
|
||
gimple stmt;
|
||
use_operand_p imm_use;
|
||
imm_use_iterator imm_iter;
|
||
|
||
/* If the PHI's result is never used, then we can just
|
||
ignore it. */
|
||
if (has_zero_uses (result))
|
||
continue;
|
||
/* We can always rebuild virtuals if needed. */
|
||
if (!is_gimple_reg (result))
|
||
continue;
|
||
FOR_EACH_IMM_USE_STMT (stmt, imm_iter, result)
|
||
{
|
||
if (gimple_code (stmt) != GIMPLE_PHI)
|
||
{
|
||
if (dump_file && (dump_flags & TDF_DETAILS))
|
||
fprintf (dump_file,
|
||
"PHI result has use in non-PHI statement.\n");
|
||
ok = false;
|
||
BREAK_FROM_IMM_USE_STMT (imm_iter);
|
||
}
|
||
else
|
||
FOR_EACH_IMM_USE_ON_STMT (imm_use, imm_iter)
|
||
{
|
||
edge e;
|
||
e = gimple_phi_arg_edge (stmt, PHI_ARG_INDEX_FROM_USE (imm_use));
|
||
if (e->src != bb)
|
||
{
|
||
if (dump_file && (dump_flags & TDF_DETAILS))
|
||
fprintf (dump_file, "PHI has use in PHI not reached from"
|
||
"empty cleanup itself.\n");
|
||
ok = false;
|
||
break;
|
||
}
|
||
}
|
||
if (!ok)
|
||
BREAK_FROM_IMM_USE_STMT (imm_iter);
|
||
}
|
||
if (!ok)
|
||
return false;
|
||
}
|
||
return ok;
|
||
}
|
||
|
||
static bool dominance_info_invalidated;
|
||
|
||
/* Information to pass into make_eh_edge_and_update_phi. */
|
||
|
||
struct update_info
|
||
{
|
||
basic_block bb_to_remove, bb;
|
||
edge edge_to_remove;
|
||
};
|
||
|
||
/* DATA points to update-info structure.
|
||
Like make_eh_edge create EH edge from DATA->bb to basic block containing
|
||
handler of REGION. In addition also update PHI operands by copying
|
||
operands from DATA->bb_to_remove. */
|
||
|
||
static void
|
||
make_eh_edge_and_update_phi (struct eh_region_d *region, void *data)
|
||
{
|
||
struct update_info *info = (struct update_info *) data;
|
||
edge e, e2;
|
||
tree lab;
|
||
basic_block src, dst;
|
||
gimple_stmt_iterator si;
|
||
|
||
lab = get_eh_region_tree_label (region);
|
||
|
||
src = info->bb;
|
||
dst = label_to_block (lab);
|
||
|
||
e = find_edge (src, dst);
|
||
if (e)
|
||
{
|
||
gcc_assert (e->flags & EDGE_EH);
|
||
e->aux = e;
|
||
return;
|
||
}
|
||
dominance_info_invalidated = true;
|
||
e2 = find_edge (info->bb_to_remove, dst);
|
||
e = make_edge (src, dst, EDGE_EH);
|
||
e->aux = e;
|
||
gcc_assert (e2);
|
||
for (si = gsi_start_phis (dst); !gsi_end_p (si); gsi_next (&si))
|
||
{
|
||
gimple phi = gsi_stmt (si);
|
||
tree use = USE_FROM_PTR (PHI_ARG_DEF_PTR_FROM_EDGE (phi, e2));
|
||
gimple def = (TREE_CODE (use) == SSA_NAME
|
||
? SSA_NAME_DEF_STMT (use) : NULL);
|
||
|
||
if (def && gimple_bb (def) == info->bb_to_remove)
|
||
{
|
||
use = USE_FROM_PTR (PHI_ARG_DEF_PTR_FROM_EDGE (def,
|
||
info->edge_to_remove));
|
||
gcc_assert (info->bb_to_remove == info->edge_to_remove->dest);
|
||
def = TREE_CODE (use) == SSA_NAME ? SSA_NAME_DEF_STMT (use) : NULL;
|
||
gcc_assert (!def
|
||
|| gimple_bb (def) != info->bb_to_remove
|
||
|| !is_gimple_reg (use));
|
||
}
|
||
SET_USE (PHI_ARG_DEF_PTR_FROM_EDGE (phi, e), use);
|
||
}
|
||
}
|
||
|
||
/* Make EH edges corresponding to STMT while updating PHI nodes after removal
|
||
empty cleanup BB_TO_REMOVE joined to BB containing STMT
|
||
by EDGE_TO_REMOVE.
|
||
|
||
Return if EDGE_TO_REMOVE was really removed. It might stay reachable when
|
||
not all EH regions are cleaned up. */
|
||
|
||
static bool
|
||
update_eh_edges (gimple stmt, basic_block bb_to_remove, edge edge_to_remove)
|
||
{
|
||
int region_nr;
|
||
bool is_resx;
|
||
bool inlinable = false;
|
||
struct update_info info;
|
||
edge_iterator ei;
|
||
edge e;
|
||
int probability_sum = 0;
|
||
bool removed = false;
|
||
|
||
info.bb_to_remove = bb_to_remove;
|
||
info.bb = gimple_bb (stmt);
|
||
info.edge_to_remove = edge_to_remove;
|
||
|
||
if (gimple_code (stmt) == GIMPLE_RESX)
|
||
{
|
||
region_nr = gimple_resx_region (stmt);
|
||
is_resx = true;
|
||
}
|
||
else
|
||
{
|
||
region_nr = lookup_stmt_eh_region (stmt);
|
||
is_resx = false;
|
||
inlinable = inlinable_call_p (stmt);
|
||
}
|
||
|
||
/* First add new edges as neccesary. */
|
||
foreach_reachable_handler (region_nr, is_resx, inlinable,
|
||
make_eh_edge_and_update_phi, &info);
|
||
|
||
/* And remove edges we didn't marked. */
|
||
for (ei = ei_start (info.bb->succs); (e = ei_safe_edge (ei)); )
|
||
{
|
||
if ((e->flags & EDGE_EH) && !e->aux)
|
||
{
|
||
dominance_info_invalidated = true;
|
||
if (e == edge_to_remove)
|
||
removed = true;
|
||
remove_edge (e);
|
||
}
|
||
else
|
||
{
|
||
e->aux = NULL;
|
||
probability_sum += e->probability;
|
||
ei_next (&ei);
|
||
}
|
||
}
|
||
|
||
/* Make CFG profile more consistent assuming that exception will resume to
|
||
first available EH handler. In practice this makes little difference, but
|
||
we get fewer consistency errors in the dumps. */
|
||
if (is_resx && EDGE_COUNT (info.bb->succs) && !probability_sum)
|
||
EDGE_SUCC (info.bb, 0)->probability = REG_BR_PROB_BASE;
|
||
return removed;
|
||
}
|
||
|
||
/* Look for basic blocks containing empty exception handler and remove them.
|
||
This is similar to jump forwarding, just across EH edges. */
|
||
|
||
static bool
|
||
cleanup_empty_eh (basic_block bb, VEC(int,heap) * label_to_region)
|
||
{
|
||
int region;
|
||
gimple_stmt_iterator si;
|
||
edge_iterator ei;
|
||
|
||
/* When handler of EH region winds up to be empty, we can safely
|
||
remove it. This leads to inner EH regions to be redirected
|
||
to outer one, if present in function. So we need to rebuild
|
||
EH edges in all sources. */
|
||
if ((region = tree_empty_eh_handler_p (bb))
|
||
&& all_phis_safe_to_merge (bb))
|
||
{
|
||
edge e;
|
||
bool found = false, removed_some = false, has_non_eh_preds = false;
|
||
gimple_stmt_iterator gsi;
|
||
|
||
/* Look for all EH regions sharing label of this block.
|
||
If they are not same as REGION, remove them and replace them
|
||
by outer region of REGION. Also note if REGION itself is one
|
||
of them. */
|
||
|
||
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
|
||
if (gimple_code (gsi_stmt (gsi)) == GIMPLE_LABEL)
|
||
{
|
||
int uid = LABEL_DECL_UID (gimple_label_label (gsi_stmt (gsi)));
|
||
int r = VEC_index (int, label_to_region, uid);
|
||
int next;
|
||
|
||
while (r)
|
||
{
|
||
next = get_next_region_sharing_label (r);
|
||
if (r == region)
|
||
found = true;
|
||
else
|
||
{
|
||
removed_some = true;
|
||
remove_eh_region_and_replace_by_outer_of (r, region);
|
||
if (dump_file && (dump_flags & TDF_DETAILS))
|
||
fprintf (dump_file, "Empty EH handler %i removed and "
|
||
"replaced by %i\n", r, region);
|
||
}
|
||
r = next;
|
||
}
|
||
}
|
||
else
|
||
break;
|
||
|
||
gcc_assert (found || removed_some);
|
||
FOR_EACH_EDGE (e, ei, bb->preds)
|
||
if (!(e->flags & EDGE_EH))
|
||
has_non_eh_preds = true;
|
||
|
||
/* When block is empty EH cleanup, but it is reachable via non-EH code too,
|
||
we can not remove the region it is resumed via, because doing so will
|
||
lead to redirection of its RESX edges.
|
||
|
||
This case will be handled later after edge forwarding if the EH cleanup
|
||
is really dead. */
|
||
|
||
if (found && !has_non_eh_preds)
|
||
{
|
||
if (dump_file && (dump_flags & TDF_DETAILS))
|
||
fprintf (dump_file, "Empty EH handler %i removed.\n", region);
|
||
remove_eh_region (region);
|
||
}
|
||
else if (!removed_some)
|
||
return false;
|
||
|
||
for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); )
|
||
{
|
||
basic_block src = e->src;
|
||
if (!(e->flags & EDGE_EH))
|
||
{
|
||
ei_next (&ei);
|
||
continue;
|
||
}
|
||
if (stmt_can_throw_internal (last_stmt (src)))
|
||
{
|
||
if (!update_eh_edges (last_stmt (src), bb, e))
|
||
ei_next (&ei);
|
||
}
|
||
else
|
||
remove_edge (e);
|
||
}
|
||
|
||
/* Verify that we eliminated all uses of PHI we are going to remove.
|
||
If we didn't, rebuild SSA on affected variable (this is allowed only
|
||
for virtuals). */
|
||
for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
|
||
{
|
||
gimple phi = gsi_stmt (si);
|
||
tree result = gimple_phi_result (phi);
|
||
if (!has_zero_uses (result))
|
||
{
|
||
use_operand_p use_p;
|
||
imm_use_iterator iter;
|
||
gimple stmt;
|
||
|
||
FOR_EACH_IMM_USE_STMT (stmt, iter, result)
|
||
{
|
||
/* We have use, see if it won't disappear after
|
||
removing BB. */
|
||
if (gimple_bb (stmt) == bb)
|
||
continue;
|
||
if (gimple_code (stmt) == GIMPLE_PHI)
|
||
{
|
||
bool bad = false;
|
||
|
||
FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
|
||
if (gimple_phi_arg_edge (stmt,
|
||
PHI_ARG_INDEX_FROM_USE (use_p))->src != bb)
|
||
{
|
||
bad = true;
|
||
break;
|
||
}
|
||
|
||
if (!bad)
|
||
continue;
|
||
}
|
||
|
||
gcc_assert (!is_gimple_reg (result));
|
||
mark_sym_for_renaming (SSA_NAME_VAR (result));
|
||
/* As we are going to delete this block we will release all
|
||
defs which makes the immediate uses on use stmts invalid.
|
||
Avoid that by replacing all uses with the bare variable
|
||
and updating the stmts. */
|
||
FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
|
||
SET_USE (use_p, SSA_NAME_VAR (result));
|
||
update_stmt (stmt);
|
||
}
|
||
}
|
||
}
|
||
if (!ei_safe_edge (ei_start (bb->preds)))
|
||
delete_basic_block (bb);
|
||
return true;
|
||
}
|
||
return false;
|
||
}
|
||
|
||
|
||
/* Perform cleanups and lowering of exception handling
|
||
1) cleanups regions with handlers doing nothing are optimized out
|
||
2) MUST_NOT_THROW regions that became dead because of 1) are optimized out
|
||
3) Info about regions that are containing instructions, and regions
|
||
reachable via local EH edges is collected
|
||
4) Eh tree is pruned for regions no longer neccesary.
|
||
*/
|
||
|
||
static unsigned int
|
||
cleanup_eh (void)
|
||
{
|
||
bool changed = false;
|
||
basic_block bb;
|
||
VEC(int,heap) * label_to_region;
|
||
int i;
|
||
|
||
if (!cfun->eh)
|
||
return 0;
|
||
if (dump_file)
|
||
{
|
||
fprintf (dump_file, "Before cleanups:\n");
|
||
dump_eh_tree (dump_file, cfun);
|
||
}
|
||
|
||
if (optimize)
|
||
{
|
||
label_to_region = label_to_region_map ();
|
||
dominance_info_invalidated = false;
|
||
/* We cannot use FOR_EACH_BB, since the basic blocks may get removed. */
|
||
for (i = NUM_FIXED_BLOCKS; i < last_basic_block; i++)
|
||
{
|
||
bb = BASIC_BLOCK (i);
|
||
if (bb)
|
||
changed |= cleanup_empty_eh (bb, label_to_region);
|
||
}
|
||
VEC_free (int, heap, label_to_region);
|
||
if (dominance_info_invalidated)
|
||
{
|
||
free_dominance_info (CDI_DOMINATORS);
|
||
free_dominance_info (CDI_POST_DOMINATORS);
|
||
}
|
||
|
||
/* Removing contained cleanup can render MUST_NOT_THROW regions empty. */
|
||
if (changed)
|
||
delete_unreachable_blocks ();
|
||
}
|
||
|
||
tree_remove_unreachable_handlers ();
|
||
if (dump_file)
|
||
{
|
||
fprintf (dump_file, "After cleanups:\n");
|
||
dump_eh_tree (dump_file, cfun);
|
||
}
|
||
|
||
return (changed ? TODO_cleanup_cfg | TODO_update_ssa : 0);
|
||
}
|
||
|
||
struct gimple_opt_pass pass_cleanup_eh = {
|
||
{
|
||
GIMPLE_PASS,
|
||
"ehcleanup", /* name */
|
||
NULL, /* gate */
|
||
cleanup_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 */
|
||
}
|
||
};
|