/* Generic routines for manipulating SSA_NAME expressions
- Copyright (C) 2003 Free Software Foundation, Inc.
+ Copyright (C) 2003, 2004, 2005 Free Software Foundation, Inc.
This file is part of GCC.
#include "tree.h"
#include "varray.h"
#include "ggc.h"
+#include "tree-flow.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
a very well defined lifetime. If someone wants to experiment with that
this is the place to try it. */
-/* Next SSA version number to be allocated. */
-unsigned int highest_ssa_version;
-
+/* Array of all SSA_NAMEs used in the function. */
+varray_type ssa_names;
+
+/* Bitmap of ssa names marked for rewriting. */
+static bitmap ssa_names_to_rewrite;
+
/* 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;
unsigned int ssa_name_nodes_created;
#endif
+/* Returns true if ssa name VAR is marked for rewrite. */
+
+bool
+marked_for_rewrite_p (tree var)
+{
+ return bitmap_bit_p (ssa_names_to_rewrite, SSA_NAME_VERSION (var));
+}
+
+/* Returns true if any ssa name is marked for rewrite. */
+
+bool
+any_marked_for_rewrite_p (void)
+{
+ if (!ssa_names_to_rewrite)
+ return false;
+
+ return !bitmap_empty_p (ssa_names_to_rewrite);
+}
+
+/* Mark ssa name VAR for rewriting. */
+
+void
+mark_for_rewrite (tree var)
+{
+ bitmap_set_bit (ssa_names_to_rewrite, SSA_NAME_VERSION (var));
+}
+
+/* Unmark all ssa names marked for rewrite. */
+
+void
+unmark_all_for_rewrite (void)
+{
+ bitmap_clear (ssa_names_to_rewrite);
+}
+
+/* Return the bitmap of ssa names to rewrite. Copy the bitmap,
+ so that the optimizers cannot access internals directly */
+
+bitmap
+marked_ssa_names (void)
+{
+ bitmap ret = BITMAP_ALLOC (NULL);
+
+ bitmap_copy (ret, ssa_names_to_rewrite);
+
+ return ret;
+}
+
/* Initialize management of SSA_NAMEs. */
void
init_ssanames (void)
{
- highest_ssa_version = UNUSED_NAME_VERSION + 1;
+ VARRAY_TREE_INIT (ssa_names, 50, "ssa_names table");
+
+ /* 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;
+ ssa_names_to_rewrite = BITMAP_ALLOC (NULL);
}
/* Finalize management of SSA_NAMEs. */
void
fini_ssanames (void)
{
+ BITMAP_FREE (ssa_names_to_rewrite);
+ ggc_free (ssa_names);
+ ssa_names = NULL;
free_ssanames = NULL;
}
{
tree t;
-#if defined ENABLE_CHECKING
- if ((!DECL_P (var)
- && TREE_CODE (var) != INDIRECT_REF)
- || (!IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (TREE_CODE (stmt)))
- && TREE_CODE (stmt) != PHI_NODE))
- abort ();
-#endif
+ gcc_assert (DECL_P (var)
+ || TREE_CODE (var) == INDIRECT_REF);
+
+ gcc_assert (!stmt || EXPR_P (stmt) || TREE_CODE (stmt) == PHI_NODE);
- /* If our free list has an element, then use it. Also reuse the
- SSA version number of the element on the free list which helps
- keep sbitmaps and arrays sized HIGHEST_SSA_VERSION smaller. */
+ /* If our free list has an element, then use it. */
if (free_ssanames)
{
- unsigned int save_version;
-
t = free_ssanames;
free_ssanames = TREE_CHAIN (free_ssanames);
#ifdef GATHER_STATISTICS
ssa_name_nodes_reused++;
#endif
- /* Clear the node so that it looks just like one we would have
- received from make_node. */
- save_version = SSA_NAME_VERSION (t);
- memset (t, 0, tree_size (t));
- TREE_SET_CODE (t, SSA_NAME);
- SSA_NAME_VERSION (t) = save_version;
+ /* 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;
}
else
{
t = make_node (SSA_NAME);
- SSA_NAME_VERSION (t) = highest_ssa_version++;
+ SSA_NAME_VERSION (t) = num_ssa_names;
+ VARRAY_PUSH_TREE (ssa_names, t);
#ifdef GATHER_STATISTICS
ssa_name_nodes_created++;
#endif
TREE_TYPE (t) = TREE_TYPE (var);
SSA_NAME_VAR (t) = var;
SSA_NAME_DEF_STMT (t) = stmt;
+ SSA_NAME_PTR_INFO (t) = NULL;
+ SSA_NAME_IN_FREE_LIST (t) = 0;
return t;
}
+
/* We no longer need the SSA_NAME expression VAR, release it so that
it may be reused.
void
release_ssa_name (tree var)
{
+ if (!var)
+ return;
+
+ /* 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)
+ return;
+
+ /* If the ssa name is marked for rewriting, it may have multiple definitions,
+ but we may happen to remove just one of them. So do not remove the
+ ssa name now. */
+ if (marked_for_rewrite_p (var))
+ return;
+
/* 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
defining statement. */
if (! SSA_NAME_IN_FREE_LIST (var))
{
+ tree saved_ssa_name_var = SSA_NAME_VAR (var);
+ int saved_ssa_name_version = SSA_NAME_VERSION (var);
+
+ VARRAY_TREE (ssa_names, SSA_NAME_VERSION (var)) = NULL;
+ memset (var, 0, tree_size (var));
+
+ /* First put back the right tree node so that the tree checking
+ macros do not complain. */
+ TREE_SET_CODE (var, SSA_NAME);
+
+ /* Restore the version number. */
+ SSA_NAME_VERSION (var) = saved_ssa_name_version;
+
+ /* Hopefully this can go away once we have the new incremental
+ SSA updating code installed. */
+ SSA_NAME_VAR (var) = saved_ssa_name_var;
+
+ /* Note this SSA_NAME is now in the first list. */
SSA_NAME_IN_FREE_LIST (var) = 1;
+
+ /* And finally link it into the free list. */
TREE_CHAIN (var) = free_ssanames;
free_ssanames = var;
}
}
+/* Creates a duplicate of a ssa name NAME defined in statement STMT. */
+
+tree
+duplicate_ssa_name (tree name, tree stmt)
+{
+ tree new_name = make_ssa_name (SSA_NAME_VAR (name), stmt);
+ struct ptr_info_def *old_ptr_info = SSA_NAME_PTR_INFO (name);
+ struct ptr_info_def *new_ptr_info;
+
+ if (!old_ptr_info)
+ return new_name;
+
+ new_ptr_info = ggc_alloc (sizeof (struct ptr_info_def));
+ *new_ptr_info = *old_ptr_info;
+
+ if (old_ptr_info->pt_vars)
+ {
+ new_ptr_info->pt_vars = BITMAP_GGC_ALLOC ();
+ bitmap_copy (new_ptr_info->pt_vars, old_ptr_info->pt_vars);
+ }
+
+ SSA_NAME_PTR_INFO (new_name) = new_ptr_info;
+ return new_name;
+}
+
+
+/* Release all the SSA_NAMEs created by STMT. */
+
+void
+release_defs (tree stmt)
+{
+ tree def;
+ ssa_op_iter iter;
+
+ FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS)
+ if (TREE_CODE (def) == SSA_NAME)
+ release_ssa_name (def);
+}
+
+
+/* Replace the symbol associated with SSA_NAME with SYM. */
+
+void
+replace_ssa_name_symbol (tree ssa_name, tree sym)
+{
+ SSA_NAME_VAR (ssa_name) = sym;
+ TREE_TYPE (ssa_name) = TREE_TYPE (sym);
+}
+
#include "gt-tree-ssanames.h"
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