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/* Iterator routines for manipulating GENERIC and GIMPLE tree statements.
Copyright (C) 2003-2019 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 3, or (at your option)
any later version.
GCC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3. If not see
<http://www.gnu.org/licenses/>. */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tree.h"
#include "tree-iterator.h"
/* This is a cache of STATEMENT_LIST nodes. We create and destroy them
fairly often during gimplification. */
static GTY ((deletable (""))) vec<tree, va_gc> *stmt_list_cache;
tree
alloc_stmt_list (void)
{
tree list;
if (!vec_safe_is_empty (stmt_list_cache))
{
list = stmt_list_cache->pop ();
memset (list, 0, sizeof (struct tree_base));
TREE_SET_CODE (list, STATEMENT_LIST);
}
else
{
list = make_node (STATEMENT_LIST);
TREE_SIDE_EFFECTS (list) = 0;
}
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));
vec_safe_push (stmt_list_cache, t);
}
/* A subroutine of append_to_statement_list{,_force}. T is not NULL. */
static void
append_to_statement_list_1 (tree t, tree *list_p)
{
tree list = *list_p;
tree_stmt_iterator i;
if (!list)
{
if (t && TREE_CODE (t) == STATEMENT_LIST)
{
*list_p = t;
return;
}
*list_p = list = alloc_stmt_list ();
}
else if (TREE_CODE (list) != STATEMENT_LIST)
{
tree first = list;
*list_p = list = alloc_stmt_list ();
i = tsi_last (list);
tsi_link_after (&i, first, TSI_CONTINUE_LINKING);
}
i = tsi_last (list);
tsi_link_after (&i, t, TSI_CONTINUE_LINKING);
}
/* Add T to the end of the list container pointed to by LIST_P.
If T is an expression with no effects, it is ignored. */
void
append_to_statement_list (tree t, tree *list_p)
{
if (t && (TREE_SIDE_EFFECTS (t) || TREE_CODE (t) == DEBUG_BEGIN_STMT))
append_to_statement_list_1 (t, list_p);
}
/* Similar, but the statement is always added, regardless of side effects. */
void
append_to_statement_list_force (tree t, tree *list_p)
{
if (t != NULL_TREE)
append_to_statement_list_1 (t, list_p);
}
/* 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<tree_statement_list_node> ();
head->prev = NULL;
head->next = NULL;
head->stmt = t;
tail = head;
}
if (TREE_CODE (t) != DEBUG_BEGIN_STMT)
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<tree_statement_list_node> ();
head->prev = NULL;
head->next = NULL;
head->stmt = t;
tail = head;
}
if (TREE_CODE (t) != DEBUG_BEGIN_STMT)
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;
}
/* Return the first expression in a sequence of COMPOUND_EXPRs, or in
a STATEMENT_LIST, disregarding DEBUG_BEGIN_STMTs, recursing into a
STATEMENT_LIST if that's the first non-DEBUG_BEGIN_STMT. */
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);
if (!n)
return NULL_TREE;
while (TREE_CODE (n->stmt) == DEBUG_BEGIN_STMT)
{
n = n->next;
if (!n)
return NULL_TREE;
}
/* If the first non-debug stmt is not a statement list, we
already know it's what we're looking for. */
if (TREE_CODE (n->stmt) != STATEMENT_LIST)
return n->stmt;
return expr_first (n->stmt);
}
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, disregarding DEBUG_BEGIN_STMTs, recursing into a
STATEMENT_LIST if that's the last non-DEBUG_BEGIN_STMT. */
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);
if (!n)
return NULL_TREE;
while (TREE_CODE (n->stmt) == DEBUG_BEGIN_STMT)
{
n = n->prev;
if (!n)
return NULL_TREE;
}
/* If the last non-debug stmt is not a statement list, we
already know it's what we're looking for. */
if (TREE_CODE (n->stmt) != STATEMENT_LIST)
return n->stmt;
return expr_last (n->stmt);
}
while (TREE_CODE (expr) == COMPOUND_EXPR)
expr = TREE_OPERAND (expr, 1);
return expr;
}
#include "gt-tree-iterator.h"