+ * Adds Projs to keep nodes for each register class, which eats the
+ * caller saved registers.
+ * Note: The caller has to make sure, that call is a Call
+ *
+ * @param call The Call node
+ * @param walk_env The walker environment
+ */
+static void lower_call_node(ir_node *call, const void *walk_env) {
+ const arch_env_t *arch_env = walk_env;
+ const arch_register_class_t *reg_class;
+ int i, j, set_size = 0, pn, keep_arity;
+ arch_isa_t *isa = arch_env_get_isa(arch_env);
+ const ir_node *proj_T = NULL;
+ ir_node **in_keep, *block = get_nodes_block(call);
+ bitset_t *proj_set;
+ const ir_edge_t *edge;
+ const arch_register_t *reg;
+
+ /* Prepare the bitset where we store the projnums which are already in use*/
+ for (i = 0; i < arch_isa_get_n_reg_class(isa); i++) {
+ reg_class = arch_isa_get_reg_class(isa, i);
+ set_size += arch_register_class_n_regs(reg_class);
+ }
+
+ in_keep = malloc(set_size * sizeof(ir_node *));
+
+ proj_set = bitset_malloc(set_size);
+ bitset_clear_all(proj_set);
+
+ /* check if there is a ProjT node and which arguments are used */
+ foreach_out_edge(call, edge) {
+ if (get_irn_mode(get_edge_src_irn(edge)) == mode_T)
+ proj_T = get_edge_src_irn(edge);
+ }
+
+ /* set all used arguments */
+ if (proj_T) {
+ foreach_out_edge(proj_T, edge) {
+ ir_node *proj = get_edge_src_irn(edge);
+
+ assert(is_Proj(proj));
+ bitset_set(proj_set, get_Proj_proj(proj));
+ }
+ }
+ else {
+ proj_T = new_r_Proj(current_ir_graph, block, call, mode_T, pn_Call_T_result);
+ last_proj = call;
+ }
+
+ /* Create for each caller save register a proj (keep node argument) */
+ /* if this proj is not already present */
+ for (i = 0; i < arch_isa_get_n_reg_class(isa); i++) {
+
+ /* reset the keep input, as we need one keep for each register class */
+ memset(in_keep, 0, set_size * sizeof(ir_node *));
+ keep_arity = 0;
+ reg_class = arch_isa_get_reg_class(isa, i);
+
+ for (j = 0; j < arch_register_class_n_regs(reg_class); j++) {
+ reg = arch_register_for_index(reg_class, j);
+
+ /* only check caller save registers */
+ if (arch_register_type_is(reg, caller_saved)) {
+ pn = isa->impl->get_projnum_for_register(isa, reg);
+ if (!bitset_is_set(proj_set, pn)) {
+ ir_node *proj = new_r_Proj(current_ir_graph, block, (ir_node *)proj_T, mode_Is, pn);
+
+ in_keep[keep_arity++] = proj;
+ }
+ }
+ }
+
+ /* ok, we found some caller save register which are not in use but must be saved */
+ if (keep_arity) {
+ be_new_Keep(reg_class, current_ir_graph, block, keep_arity, in_keep);
+ }
+ }
+
+ bitset_free(proj_set);
+ return;
+}
+
+
+
+/**
+ * Calls the backend code generator functions to lower Spill and
+ * Reload nodes into Store and Load. The backend is fully responsible
+ * for creating the new nodes and setting their input correct.
+ * Note: The caller of this has to make sure that irn is a Spill
+ * or Reload!
+ *
+ * @param irn The Spill/Reload node
+ * @param walk_env The walker environment
+ */
+static void lower_spill_reload(ir_node *irn, void *walk_env) {
+ lower_env_t *env = walk_env;
+ arch_code_generator_t *cg = env->chord_env->main_env->cg;
+ const arch_env_t *aenv = env->chord_env->main_env->arch_env;
+ ir_node *res = NULL;
+ ir_node *sched_point;
+
+ if (be_is_Spill(irn) && cg->impl->lower_spill) {
+ res = cg->impl->lower_spill(cg, irn);
+ }
+ else if (be_is_Reload(irn) && cg->impl->lower_reload) {
+ res = cg->impl->lower_reload(cg, irn);
+ if (res && res != irn) {
+ /* copy the result register from the reload to the load */
+ arch_set_irn_register(aenv, res, arch_get_irn_register(aenv, irn));
+ }
+ }
+
+ if (res && res != irn) {
+ sched_point = sched_prev(irn);
+ sched_remove(irn);
+ exchange(irn, res);
+ sched_add_after(sched_point, res);
+ }
+ else {
+ DBG((env->dbg_module, LEVEL_1, "node %+F not lowered\n", irn));
+ }
+
+ return;
+}
+
+
+/**
+ * Calls the corresponding lowering function for the node.
+ *
+ * @param irn The node to be checked for lowering
+ * @param walk_env The walker environment
+ */
+static void lower_nodes_before_sched_walker(ir_node *irn, const void *walk_env) {
+ const arch_env_t *arch_env = walk_env;
+
+ if (!is_Block(irn) && !is_Proj(irn)) {
+ if (is_Call(arch_env, irn)) {
+ lower_call_node(irn, walk_env);
+ }
+ }
+
+ return;
+}
+
+
+/**
+ * Calls the corresponding lowering function for the node.
+ *
+ * @param irn The node to be checked for lowering
+ * @param walk_env The walker environment
+ */
+static void lower_nodes_after_ra_walker(ir_node *irn, void *walk_env) {
+ lower_env_t *env = walk_env;
+ const arch_env_t *arch_env = env->chord_env->main_env->arch_env;
+
+ if (!is_Block(irn) && !is_Proj(irn)) {
+ if (is_Perm(arch_env, irn)) {
+ lower_perm_node(irn, walk_env);
+ }
+ else if (be_is_Spill(irn) || be_is_Reload(irn)) {
+ lower_spill_reload(irn, walk_env);
+ }
+ }
+
+ return;
+}
+
+
+
+/**
+ * Walks over all blocks in an irg and performs lowering need
+ * to be done before scheduling (e.g. call lowering).
+ *
+ * @param chord_env The chordal environment containing the irg
+ * @param do_copy 1 == resolve cycles with a free reg if available
+ */
+void lower_nodes_before_sched(ir_graph *irg, const void *env) {
+ irg_walk_blkwise_graph(irg, NULL, lower_nodes_before_sched_walker, env);
+}
+
+
+
+/**
+ * Walks over all blocks in an irg and performs lowering need to be
+ * done after register allocation (e.g. perm and spill/reload lowering).