/* Iterator routines for manipulating GENERIC and GIMPLE tree statements.
Copyright (C) 2003, 2004 Free Software Foundation, Inc.
Contributed by Andrew MacLeod <amacleod@redhat.com>
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
GCC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING. If not, write to
the Free Software Foundation, 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA. */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tree.h"
#include "tree-gimple.h"
#include "tree-iterator.h"
#include "ggc.h"
/* This is a cache of STATEMENT_LIST nodes. We create and destroy them
fairly often during gimplification. */
static GTY ((deletable (""))) tree stmt_list_cache;
tree
alloc_stmt_list (void)
{
tree list = stmt_list_cache;
if (list)
{
stmt_list_cache = TREE_CHAIN (list);
gcc_assert (stmt_list_cache != list);
memset (list, 0, sizeof(struct tree_common));
TREE_SET_CODE (list, STATEMENT_LIST);
}
else
list = make_node (STATEMENT_LIST);
TREE_TYPE (list) = void_type_node;
return list;
}
void
free_stmt_list (tree t)
{
gcc_assert (!STATEMENT_LIST_HEAD (t));
gcc_assert (!STATEMENT_LIST_TAIL (t));
/* If this triggers, it's a sign that the same list is being freed
twice. */
gcc_assert (t != stmt_list_cache || stmt_list_cache == NULL);
TREE_CHAIN (t) = stmt_list_cache;
stmt_list_cache = t;
}
/* Links a statement, or a chain of statements, before the current stmt. */
void
tsi_link_before (tree_stmt_iterator *i, tree t, enum tsi_iterator_update mode)
{
struct tree_statement_list_node *head, *tail, *cur;
/* Die on looping. */
gcc_assert (t != i->container);
if (TREE_CODE (t) == STATEMENT_LIST)
{
head = STATEMENT_LIST_HEAD (t);
tail = STATEMENT_LIST_TAIL (t);
STATEMENT_LIST_HEAD (t) = NULL;
STATEMENT_LIST_TAIL (t) = NULL;
free_stmt_list (t);
/* Empty statement lists need no work. */
if (!head || !tail)
{
gcc_assert (head == tail);
return;
}
}
else
{
head = ggc_alloc (sizeof (*head));
head->prev = NULL;
head->next = NULL;
head->stmt = t;
tail = head;
}
TREE_SIDE_EFFECTS (i->container) = 1;
cur = i->ptr;
/* Link it into the list. */
if (cur)
{
head->prev = cur->prev;
if (head->prev)
head->prev->next = head;
else
STATEMENT_LIST_HEAD (i->container) = head;
tail->next = cur;
cur->prev = tail;
}
else
{
head->prev = STATEMENT_LIST_TAIL (i->container);
if (head->prev)
head->prev->next = head;
else
STATEMENT_LIST_HEAD (i->container) = head;
STATEMENT_LIST_TAIL (i->container) = tail;
}
/* Update the iterator, if requested. */
switch (mode)
{
case TSI_NEW_STMT:
case TSI_CONTINUE_LINKING:
case TSI_CHAIN_START:
i->ptr = head;
break;
case TSI_CHAIN_END:
i->ptr = tail;
break;
case TSI_SAME_STMT:
break;
}
}
/* Links a statement, or a chain of statements, after the current stmt. */
void
tsi_link_after (tree_stmt_iterator *i, tree t, enum tsi_iterator_update mode)
{
struct tree_statement_list_node *head, *tail, *cur;
/* Die on looping. */
gcc_assert (t != i->container);
if (TREE_CODE (t) == STATEMENT_LIST)
{
head = STATEMENT_LIST_HEAD (t);
tail = STATEMENT_LIST_TAIL (t);
STATEMENT_LIST_HEAD (t) = NULL;
STATEMENT_LIST_TAIL (t) = NULL;
free_stmt_list (t);
/* Empty statement lists need no work. */
if (!head || !tail)
{
gcc_assert (head == tail);
return;
}
}
else
{
head = ggc_alloc (sizeof (*head));
head->prev = NULL;
head->next = NULL;
head->stmt = t;
tail = head;
}
TREE_SIDE_EFFECTS (i->container) = 1;
cur = i->ptr;
/* Link it into the list. */
if (cur)
{
tail->next = cur->next;
if (tail->next)
tail->next->prev = tail;
else
STATEMENT_LIST_TAIL (i->container) = tail;
head->prev = cur;
cur->next = head;
}
else
{
gcc_assert (!STATEMENT_LIST_TAIL (i->container));
STATEMENT_LIST_HEAD (i->container) = head;
STATEMENT_LIST_TAIL (i->container) = tail;
}
/* Update the iterator, if requested. */
switch (mode)
{
case TSI_NEW_STMT:
case TSI_CHAIN_START:
i->ptr = head;
break;
case TSI_CONTINUE_LINKING:
case TSI_CHAIN_END:
i->ptr = tail;
break;
case TSI_SAME_STMT:
gcc_assert (cur);
break;
}
}
/* Remove a stmt from the tree list. The iterator is updated to point to
the next stmt. */
void
tsi_delink (tree_stmt_iterator *i)
{
struct tree_statement_list_node *cur, *next, *prev;
cur = i->ptr;
next = cur->next;
prev = cur->prev;
if (prev)
prev->next = next;
else
STATEMENT_LIST_HEAD (i->container) = next;
if (next)
next->prev = prev;
else
STATEMENT_LIST_TAIL (i->container) = prev;
if (!next && !prev)
TREE_SIDE_EFFECTS (i->container) = 0;
i->ptr = next;
}
/* Move all statements in the statement list after I to a new
statement list. I itself is unchanged. */
tree
tsi_split_statement_list_after (const tree_stmt_iterator *i)
{
struct tree_statement_list_node *cur, *next;
tree old_sl, new_sl;
cur = i->ptr;
/* How can we possibly split after the end, or before the beginning? */
gcc_assert (cur);
next = cur->next;
old_sl = i->container;
new_sl = alloc_stmt_list ();
TREE_SIDE_EFFECTS (new_sl) = 1;
STATEMENT_LIST_HEAD (new_sl) = next;
STATEMENT_LIST_TAIL (new_sl) = STATEMENT_LIST_TAIL (old_sl);
STATEMENT_LIST_TAIL (old_sl) = cur;
cur->next = NULL;
next->prev = NULL;
return new_sl;
}
/* Move all statements in the statement list before I to a new
statement list. I is set to the head of the new list. */
tree
tsi_split_statement_list_before (tree_stmt_iterator *i)
{
struct tree_statement_list_node *cur, *prev;
tree old_sl, new_sl;
cur = i->ptr;
/* How can we possibly split after the end, or before the beginning? */
gcc_assert (cur);
prev = cur->prev;
old_sl = i->container;
new_sl = alloc_stmt_list ();
TREE_SIDE_EFFECTS (new_sl) = 1;
i->container = new_sl;
STATEMENT_LIST_HEAD (new_sl) = cur;
STATEMENT_LIST_TAIL (new_sl) = STATEMENT_LIST_TAIL (old_sl);
STATEMENT_LIST_TAIL (old_sl) = prev;
cur->prev = NULL;
if (prev)
prev->next = NULL;
return new_sl;
}
/* Return the first expression in a sequence of COMPOUND_EXPRs,
or in a STATEMENT_LIST. */
tree
expr_first (tree expr)
{
if (expr == NULL_TREE)
return expr;
if (TREE_CODE (expr) == STATEMENT_LIST)
{
struct tree_statement_list_node *n = STATEMENT_LIST_HEAD (expr);
return n ? n->stmt : NULL_TREE;
}
while (TREE_CODE (expr) == COMPOUND_EXPR)
expr = TREE_OPERAND (expr, 0);
return expr;
}
/* Return the last expression in a sequence of COMPOUND_EXPRs,
or in a STATEMENT_LIST. */
tree
expr_last (tree expr)
{
if (expr == NULL_TREE)
return expr;
if (TREE_CODE (expr) == STATEMENT_LIST)
{
struct tree_statement_list_node *n = STATEMENT_LIST_TAIL (expr);
return n ? n->stmt : NULL_TREE;
}
while (TREE_CODE (expr) == COMPOUND_EXPR)
expr = TREE_OPERAND (expr, 1);
return expr;
}
/* If EXPR is a single statement return it. If EXPR is a
STATEMENT_LIST containing exactly one statement S, return S.
Otherwise, return NULL. */
tree
expr_only (tree expr)
{
if (expr == NULL_TREE)
return NULL_TREE;
if (TREE_CODE (expr) == STATEMENT_LIST)
{
struct tree_statement_list_node *n = STATEMENT_LIST_TAIL (expr);
if (n && STATEMENT_LIST_HEAD (expr) == n)
return n->stmt;
else
return NULL_TREE;
}
if (TREE_CODE (expr) == COMPOUND_EXPR)
return NULL_TREE;
return expr;
}
#include "gt-tree-iterator.h"