# ipa.c   [plain text]

```/* Basic IPA optimizations and utilities.
Copyright (C) 2003, 2004, 2005 Free Software Foundation, Inc.

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it under
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 "tm.h"
#include "cgraph.h"

/* Fill array order with all nodes with output flag set in the reverse
topological order.  */

int
cgraph_postorder (struct cgraph_node **order)
{
struct cgraph_node *node, *node2;
int stack_size = 0;
int order_pos = 0;
struct cgraph_edge *edge, last;

struct cgraph_node **stack =
XCNEWVEC (struct cgraph_node *, cgraph_n_nodes);

/* We have to deal with cycles nicely, so use a depth first traversal
output algorithm.  Ignore the fact that some functions won't need
to be output and put them into order as well, so we get dependencies
right through intline functions.  */
for (node = cgraph_nodes; node; node = node->next)
node->aux = NULL;
for (node = cgraph_nodes; node; node = node->next)
if (!node->aux)
{
node2 = node;
if (!node->callers)
node->aux = &last;
else
node->aux = node->callers;
while (node2)
{
while (node2->aux != &last)
{
edge = node2->aux;
if (edge->next_caller)
node2->aux = edge->next_caller;
else
node2->aux = &last;
if (!edge->caller->aux)
{
if (!edge->caller->callers)
edge->caller->aux = &last;
else
edge->caller->aux = edge->caller->callers;
stack[stack_size++] = node2;
node2 = edge->caller;
break;
}
}
if (node2->aux == &last)
{
order[order_pos++] = node2;
if (stack_size)
node2 = stack[--stack_size];
else
node2 = NULL;
}
}
}
free (stack);
for (node = cgraph_nodes; node; node = node->next)
node->aux = NULL;
return order_pos;
}

/* Perform reachability analysis and reclaim all unreachable nodes.
If BEFORE_INLINING_P is true this function is called before inlining
decisions has been made.  If BEFORE_INLINING_P is false this function also
removes unneeded bodies of extern inline functions.  */

bool
cgraph_remove_unreachable_nodes (bool before_inlining_p, FILE *file)
{
struct cgraph_node *first = (void *) 1;
struct cgraph_node *node, *next;
bool changed = false;
int insns = 0;

#ifdef ENABLE_CHECKING
verify_cgraph ();
#endif
if (file)
fprintf (file, "\nReclaiming functions:");
#ifdef ENABLE_CHECKING
for (node = cgraph_nodes; node; node = node->next)
gcc_assert (!node->aux);
#endif
for (node = cgraph_nodes; node; node = node->next)
if (node->needed && !node->global.inlined_to
&& ((!DECL_EXTERNAL (node->decl))
|| !node->analyzed
|| before_inlining_p))
{
node->aux = first;
first = node;
}
else
gcc_assert (!node->aux);

/* Perform reachability analysis.  As a special case do not consider
extern inline functions not inlined as live because we won't output
them at all.  */
while (first != (void *) 1)
{
struct cgraph_edge *e;
node = first;
first = first->aux;

for (e = node->callees; e; e = e->next_callee)
if (!e->callee->aux
&& node->analyzed
&& (!e->inline_failed || !e->callee->analyzed
|| (!DECL_EXTERNAL (e->callee->decl))
|| before_inlining_p))
{
e->callee->aux = first;
first = e->callee;
}
}

/* Remove unreachable nodes.  Extern inline functions need special care;
Unreachable extern inline functions shall be removed.
Reachable extern inline functions we never inlined shall get their bodies
eliminated.
Reachable extern inline functions we sometimes inlined will be turned into
unanalyzed nodes so they look like for true extern functions to the rest
of code.  Body of such functions is released via remove_node once the
inline clones are eliminated.  */
for (node = cgraph_nodes; node; node = next)
{
next = node->next;
if (!node->aux)
{
int local_insns;
tree decl = node->decl;

node->global.inlined_to = NULL;
if (DECL_STRUCT_FUNCTION (decl))
local_insns = node->local.self_insns;
else
local_insns = 0;
if (file)
fprintf (file, " %s", cgraph_node_name (node));
if (!node->analyzed || !DECL_EXTERNAL (node->decl)
|| before_inlining_p)
cgraph_remove_node (node);
else
{
struct cgraph_edge *e;

for (e = node->callers; e; e = e->next_caller)
if (e->caller->aux)
break;
if (e || node->needed)
{
struct cgraph_node *clone;

for (clone = node->next_clone; clone;
clone = clone->next_clone)
if (clone->aux)
break;
if (!clone)
{
DECL_SAVED_TREE (node->decl) = NULL;
DECL_STRUCT_FUNCTION (node->decl) = NULL;
DECL_INITIAL (node->decl) = error_mark_node;
node->analyzed = false;
}
cgraph_node_remove_callees (node);
node->analyzed = false;
}
else
cgraph_remove_node (node);
}
if (!DECL_SAVED_TREE (decl))
insns += local_insns;
changed = true;
}
}
for (node = cgraph_nodes; node; node = node->next)
node->aux = NULL;
if (file)
fprintf (file, "\nReclaimed %i insns", insns);
return changed;
}
```