{
return new pass_ipa_cdtor_merge (ctxt);
}
+
+/* Invalid pointer representing BOTTOM for single user dataflow. */
+#define BOTTOM ((cgraph_node *)(size_t) 2)
+
+/* Meet operation for single user dataflow.
+ Here we want to associate variables with sigle function that may access it.
+
+ FUNCTION is current single user of a variable, VAR is variable that uses it.
+ Latttice is stored in SINGLE_USER_MAP.
+
+ We represent:
+ - TOP by no entry in SIGNLE_USER_MAP
+ - BOTTOM by BOTTOM in AUX pointer (to save lookups)
+ - known single user by cgraph pointer in SINGLE_USER_MAP. */
+
+cgraph_node *
+meet (cgraph_node *function, varpool_node *var,
+ pointer_map<cgraph_node *> &single_user_map)
+{
+ struct cgraph_node *user, **f;
+
+ if (var->aux == BOTTOM)
+ return BOTTOM;
+
+ f = single_user_map.contains (var);
+ if (!f)
+ return function;
+ user = *f;
+ if (!function)
+ return user;
+ else if (function != user)
+ return BOTTOM;
+ else
+ return function;
+}
+
+/* Propagation step of single-use dataflow.
+
+ Check all uses of VNODE and see if they are used by single function FUNCTION.
+ SINGLE_USER_MAP represents the dataflow lattice. */
+
+cgraph_node *
+propagate_single_user (varpool_node *vnode, cgraph_node *function,
+ pointer_map<cgraph_node *> &single_user_map)
+{
+ int i;
+ struct ipa_ref *ref;
+
+ gcc_assert (!vnode->externally_visible);
+
+ /* If node is an alias, first meet with its target. */
+ if (vnode->alias)
+ function = meet (function, varpool_alias_target (vnode), single_user_map);
+
+ /* Check all users and see if they correspond to a single function. */
+ for (i = 0;
+ ipa_ref_list_referring_iterate (&vnode->ref_list, i, ref)
+ && function != BOTTOM; i++)
+ {
+ struct cgraph_node *cnode = dyn_cast <cgraph_node *> (ref->referring);
+ if (cnode)
+ {
+ if (cnode->global.inlined_to)
+ cnode = cnode->global.inlined_to;
+ if (!function)
+ function = cnode;
+ else if (function != cnode)
+ function = BOTTOM;
+ }
+ else
+ function = meet (function, dyn_cast <varpool_node *> (ref->referring), single_user_map);
+ }
+ return function;
+}
+
+/* Pass setting used_by_single_function flag.
+ This flag is set on variable when there is only one function that may possibly
+ referr to it. */
+
+static unsigned int
+ipa_single_use (void)
+{
+ varpool_node *first = (varpool_node *) (void *) 1;
+ varpool_node *var;
+ pointer_map<cgraph_node *> single_user_map;
+
+ FOR_EACH_DEFINED_VARIABLE (var)
+ if (!varpool_all_refs_explicit_p (var))
+ var->aux = BOTTOM;
+ else
+ {
+ /* Enqueue symbol for dataflow. */
+ var->aux = first;
+ first = var;
+ }
+
+ /* The actual dataflow. */
+
+ while (first != (void *) 1)
+ {
+ cgraph_node *user, *orig_user, **f;
+
+ var = first;
+ first = (varpool_node *)first->aux;
+
+ f = single_user_map.contains (var);
+ if (f)
+ orig_user = *f;
+ else
+ orig_user = NULL;
+ user = propagate_single_user (var, orig_user, single_user_map);
+
+ gcc_checking_assert (var->aux != BOTTOM);
+
+ /* If user differs, enqueue all references. */
+ if (user != orig_user)
+ {
+ unsigned int i;
+ ipa_ref *ref;
+
+ *single_user_map.insert (var) = user;
+
+ /* Enqueue all aliases for re-processing. */
+ for (i = 0;
+ ipa_ref_list_referring_iterate (&var->ref_list, i, ref); i++)
+ if (ref->use == IPA_REF_ALIAS
+ && !ref->referring->aux)
+ {
+ ref->referring->aux = first;
+ first = dyn_cast <varpool_node *> (ref->referring);
+ }
+ /* Enqueue all users for re-processing. */
+ for (i = 0;
+ ipa_ref_list_reference_iterate (&var->ref_list, i, ref); i++)
+ if (!ref->referred->aux
+ && ref->referred->definition
+ && is_a <varpool_node *> (ref->referred))
+ {
+ ref->referred->aux = first;
+ first = dyn_cast <varpool_node *> (ref->referred);
+ }
+
+ /* If user is BOTTOM, just punt on this var. */
+ if (user == BOTTOM)
+ var->aux = BOTTOM;
+ else
+ var->aux = NULL;
+ }
+ else
+ var->aux = NULL;
+ }
+
+ FOR_EACH_DEFINED_VARIABLE (var)
+ {
+ if (var->aux != BOTTOM)
+ {
+#ifdef ENABLE_CHECKING
+ if (!single_user_map.contains (var))
+ gcc_assert (single_user_map.contains (var));
+#endif
+ if (dump_file)
+ {
+ fprintf (dump_file, "Variable %s/%i is used by single function\n",
+ var->name (), var->order);
+ }
+ var->used_by_single_function = true;
+ }
+ var->aux = NULL;
+ }
+ return 0;
+}
+
+namespace {
+
+const pass_data pass_data_ipa_single_use =
+{
+ IPA_PASS, /* type */
+ "single-use", /* name */
+ OPTGROUP_NONE, /* optinfo_flags */
+ true, /* has_execute */
+ TV_CGRAPHOPT, /* tv_id */
+ 0, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ 0, /* todo_flags_finish */
+};
+
+class pass_ipa_single_use : public ipa_opt_pass_d
+{
+public:
+ pass_ipa_single_use (gcc::context *ctxt)
+ : ipa_opt_pass_d (pass_data_ipa_single_use, ctxt,
+ NULL, /* generate_summary */
+ NULL, /* write_summary */
+ NULL, /* read_summary */
+ NULL, /* write_optimization_summary */
+ NULL, /* read_optimization_summary */
+ NULL, /* stmt_fixup */
+ 0, /* function_transform_todo_flags_start */
+ NULL, /* function_transform */
+ NULL) /* variable_transform */
+ {}
+
+ /* opt_pass methods: */
+ virtual bool gate (function *);
+ virtual unsigned int execute (function *) { return ipa_single_use (); }
+
+}; // class pass_ipa_single_use
+
+bool
+pass_ipa_single_use::gate (function *)
+{
+ return optimize;
+}
+
+} // anon namespace
+
+ipa_opt_pass_d *
+make_pass_ipa_single_use (gcc::context *ctxt)
+{
+ return new pass_ipa_single_use (ctxt);
+}
projects / thirdparty / gcc.git / commitdiff
