/* Generic routines for manipulating SSA_NAME expressions
- Copyright (C) 2003, 2004, 2005 Free Software Foundation, Inc.
-
+ Copyright (C) 2003, 2004, 2005, 2007, 2008, 2009
+ Free Software Foundation, Inc.
+
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)
+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 COPYING. If not, write to
-the Free Software Foundation, 59 Temple Place - Suite 330,
-Boston, MA 02111-1307, USA. */
+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 "tm.h"
#include "tree.h"
-#include "varray.h"
#include "ggc.h"
#include "tree-flow.h"
+#include "tree-pass.h"
/* Rewriting a function into SSA form can create a huge number of SSA_NAMEs,
many of which may be thrown away shortly after their creation if jumps
- were threaded through PHI nodes.
+ were threaded through PHI nodes.
While our garbage collection mechanisms will handle this situation, it
is extremely wasteful to create nodes and throw them away, especially
Right now we maintain our free list on a per-function basis. It may
or may not make sense to maintain the free list for the duration of
- a compilation unit.
+ a compilation unit.
External code should rely solely upon HIGHEST_SSA_VERSION and the
externally defined functions. External code should not know about
We could also use a zone allocator for these objects since they have
a very well defined lifetime. If someone wants to experiment with that
this is the place to try it. */
-
-/* Array of all SSA_NAMEs used in the function. */
-varray_type ssa_names;
-
-/* Free list of SSA_NAMEs. This list is wiped at the end of each function
- after we leave SSA form. */
-static GTY (()) tree free_ssanames;
/* Version numbers with special meanings. We start allocating new version
numbers after the special ones. */
unsigned int ssa_name_nodes_created;
#endif
-/* Initialize management of SSA_NAMEs. */
+/* Initialize management of SSA_NAMEs to default SIZE. If SIZE is
+ zero use default. */
void
-init_ssanames (void)
+init_ssanames (struct function *fn, int size)
{
- VARRAY_TREE_INIT (ssa_names, 50, "ssa_names table");
+ if (size < 50)
+ size = 50;
+
+ SSANAMES (fn) = VEC_alloc (tree, gc, size);
/* Version 0 is special, so reserve the first slot in the table. Though
currently unused, we may use version 0 in alias analysis as part of
the heuristics used to group aliases when the alias sets are too
- large. */
- VARRAY_PUSH_TREE (ssa_names, NULL_TREE);
- free_ssanames = NULL;
+ large.
+
+ We use VEC_quick_push here because we know that SSA_NAMES has at
+ least 50 elements reserved in it. */
+ VEC_quick_push (tree, SSANAMES (fn), NULL_TREE);
+ FREE_SSANAMES (fn) = NULL;
+
+ SYMS_TO_RENAME (fn) = BITMAP_GGC_ALLOC ();
}
/* Finalize management of SSA_NAMEs. */
void
fini_ssanames (void)
{
- ggc_free (ssa_names);
- ssa_names = NULL;
- free_ssanames = NULL;
+ VEC_free (tree, gc, SSANAMES (cfun));
+ FREE_SSANAMES (cfun) = NULL;
}
/* Dump some simple statistics regarding the re-use of SSA_NAME nodes. */
}
#endif
-/* Return an SSA_NAME node for variable VAR defined in statement STMT.
- STMT may be an empty statement for artificial references (e.g., default
- definitions created when a variable is used without a preceding
- definition). */
+/* Return an SSA_NAME node for variable VAR defined in statement STMT
+ in function FN. STMT may be an empty statement for artificial
+ references (e.g., default definitions created when a variable is
+ used without a preceding definition). */
tree
-make_ssa_name (tree var, tree stmt)
+make_ssa_name_fn (struct function *fn, tree var, gimple stmt)
{
tree t;
- ssa_imm_use_t *imm;
-
- gcc_assert (DECL_P (var)
- || TREE_CODE (var) == INDIRECT_REF);
+ use_operand_p imm;
- gcc_assert (!stmt || EXPR_P (stmt) || TREE_CODE (stmt) == PHI_NODE);
+ gcc_assert (DECL_P (var));
/* If our free list has an element, then use it. */
- if (free_ssanames)
+ if (FREE_SSANAMES (fn))
{
- t = free_ssanames;
- free_ssanames = TREE_CHAIN (free_ssanames);
+ t = FREE_SSANAMES (fn);
+ FREE_SSANAMES (fn) = TREE_CHAIN (FREE_SSANAMES (fn));
#ifdef GATHER_STATISTICS
ssa_name_nodes_reused++;
#endif
/* The node was cleared out when we put it on the free list, so
there is no need to do so again here. */
gcc_assert (ssa_name (SSA_NAME_VERSION (t)) == NULL);
- VARRAY_TREE (ssa_names, SSA_NAME_VERSION (t)) = t;
+ VEC_replace (tree, SSANAMES (fn), SSA_NAME_VERSION (t), t);
}
else
{
t = make_node (SSA_NAME);
- SSA_NAME_VERSION (t) = num_ssa_names;
- VARRAY_PUSH_TREE (ssa_names, t);
+ SSA_NAME_VERSION (t) = VEC_length (tree, SSANAMES (fn));
+ VEC_safe_push (tree, gc, SSANAMES (fn), t);
#ifdef GATHER_STATISTICS
ssa_name_nodes_created++;
#endif
SSA_NAME_DEF_STMT (t) = stmt;
SSA_NAME_PTR_INFO (t) = NULL;
SSA_NAME_IN_FREE_LIST (t) = 0;
+ SSA_NAME_IS_DEFAULT_DEF (t) = 0;
imm = &(SSA_NAME_IMM_USE_NODE (t));
imm->use = NULL;
imm->prev = imm;
imm->next = imm;
- imm->stmt = t;
+ imm->loc.ssa_name = t;
return t;
}
/* We no longer need the SSA_NAME expression VAR, release it so that
- it may be reused.
+ it may be reused.
Note it is assumed that no calls to make_ssa_name will be made
until all uses of the ssa name are released and that the only
/* Never release the default definition for a symbol. It's a
special SSA name that should always exist once it's created. */
- if (var == var_ann (SSA_NAME_VAR (var))->default_def)
+ if (SSA_NAME_IS_DEFAULT_DEF (var))
return;
/* If VAR has been registered for SSA updating, don't remove it.
/* release_ssa_name can be called multiple times on a single SSA_NAME.
However, it should only end up on our free list one time. We
keep a status bit in the SSA_NAME node itself to indicate it has
- been put on the free list.
+ been put on the free list.
Note that once on the freelist you can not reference the SSA_NAME's
defining statement. */
{
tree saved_ssa_name_var = SSA_NAME_VAR (var);
int saved_ssa_name_version = SSA_NAME_VERSION (var);
- ssa_imm_use_t *imm = &(SSA_NAME_IMM_USE_NODE (var));
+ use_operand_p imm = &(SSA_NAME_IMM_USE_NODE (var));
+
+ if (MAY_HAVE_DEBUG_STMTS)
+ insert_debug_temp_for_var_def (NULL, var);
#ifdef ENABLE_CHECKING
verify_imm_links (stderr, var);
while (imm->next != imm)
delink_imm_use (imm->next);
- VARRAY_TREE (ssa_names, SSA_NAME_VERSION (var)) = NULL;
+ VEC_replace (tree, SSANAMES (cfun),
+ SSA_NAME_VERSION (var), NULL_TREE);
memset (var, 0, tree_size (var));
imm->prev = imm;
imm->next = imm;
- imm->stmt = var;
+ imm->loc.ssa_name = var;
+
/* First put back the right tree node so that the tree checking
macros do not complain. */
TREE_SET_CODE (var, SSA_NAME);
SSA_NAME_IN_FREE_LIST (var) = 1;
/* And finally link it into the free list. */
- TREE_CHAIN (var) = free_ssanames;
- free_ssanames = var;
+ TREE_CHAIN (var) = FREE_SSANAMES (cfun);
+ FREE_SSANAMES (cfun) = var;
}
}
/* Creates a duplicate of a ssa name NAME defined in statement STMT. */
tree
-duplicate_ssa_name (tree name, tree stmt)
+duplicate_ssa_name (tree name, gimple stmt)
{
tree new_name = make_ssa_name (SSA_NAME_VAR (name), stmt);
struct ptr_info_def *old_ptr_info = SSA_NAME_PTR_INFO (name);
if (!ptr_info)
return;
- new_ptr_info = ggc_alloc (sizeof (struct ptr_info_def));
+ new_ptr_info = GGC_NEW (struct ptr_info_def);
*new_ptr_info = *ptr_info;
- if (ptr_info->pt_vars)
- {
- new_ptr_info->pt_vars = BITMAP_GGC_ALLOC ();
- bitmap_copy (new_ptr_info->pt_vars, ptr_info->pt_vars);
- }
-
SSA_NAME_PTR_INFO (name) = new_ptr_info;
}
/* Release all the SSA_NAMEs created by STMT. */
void
-release_defs (tree stmt)
+release_defs (gimple stmt)
{
tree def;
ssa_op_iter iter;
+ /* Make sure that we are in SSA. Otherwise, operand cache may point
+ to garbage. */
+ gcc_assert (gimple_in_ssa_p (cfun));
+
FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS)
if (TREE_CODE (def) == SSA_NAME)
release_ssa_name (def);
TREE_TYPE (ssa_name) = TREE_TYPE (sym);
}
-#include "gt-tree-ssanames.h"
+/* Return SSA names that are unused to GGC memory. This is used to keep
+ footprint of compiler during interprocedural optimization.
+ As a side effect the SSA_NAME_VERSION number reuse is reduced
+ so this function should not be used too often. */
+static unsigned int
+release_dead_ssa_names (void)
+{
+ tree t, next;
+ int n = 0;
+ referenced_var_iterator rvi;
+
+ /* Current defs point to various dead SSA names that in turn points to dead
+ statements so bunch of dead memory is held from releasing. */
+ FOR_EACH_REFERENCED_VAR (t, rvi)
+ set_current_def (t, NULL);
+ /* Now release the freelist. */
+ for (t = FREE_SSANAMES (cfun); t; t = next)
+ {
+ next = TREE_CHAIN (t);
+ /* Dangling pointers might make GGC to still see dead SSA names, so it is
+ important to unlink the list and avoid GGC from seeing all subsequent
+ SSA names. In longer run we want to have all dangling pointers here
+ removed (since they usually go through dead statements that consume
+ considerable amounts of memory). */
+ TREE_CHAIN (t) = NULL_TREE;
+ n++;
+ }
+ FREE_SSANAMES (cfun) = NULL;
+
+ /* Cgraph edges has been invalidated and point to dead statement. We need to
+ remove them now and will rebuild it before next IPA pass. */
+ cgraph_node_remove_callees (cgraph_node (current_function_decl));
+
+ if (dump_file)
+ fprintf (dump_file, "Released %i names, %.2f%%\n", n, n * 100.0 / num_ssa_names);
+ return 0;
+}
+
+struct gimple_opt_pass pass_release_ssa_names =
+{
+ {
+ GIMPLE_PASS,
+ "release_ssa", /* name */
+ NULL, /* gate */
+ release_dead_ssa_names, /* execute */
+ NULL, /* sub */
+ NULL, /* next */
+ 0, /* static_pass_number */
+ TV_NONE, /* tv_id */
+ PROP_ssa, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ TODO_dump_func /* todo_flags_finish */
+ }
+};
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