2 * Copyright (C) 1995-2011 University of Karlsruhe. All right reserved.
4 * This file is part of libFirm.
6 * This file may be distributed and/or modified under the terms of the
7 * GNU General Public License version 2 as published by the Free Software
8 * Foundation and appearing in the file LICENSE.GPL included in the
9 * packaging of this file.
11 * Licensees holding valid libFirm Professional Edition licenses may use
12 * this file in accordance with the libFirm Commercial License.
13 * Agreement provided with the Software.
15 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
16 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * @brief Lowering of Calls with compound parameters and return types.
23 * @author Michael Beck
30 #include "lower_calls.h"
41 #include "iroptimize.h"
46 static pmap *pointer_types;
47 static pmap *lowered_mtps;
50 * Default implementation for finding a pointer type for a given element type.
51 * Simple create a new one.
53 static ir_type *get_pointer_type(ir_type *dest_type)
55 ir_type *res = (ir_type*)pmap_get(pointer_types, dest_type);
57 res = new_type_pointer(dest_type);
58 pmap_insert(pointer_types, dest_type, res);
63 static void fix_parameter_entities(ir_graph *irg, size_t n_compound_ret)
65 ir_type *frame_type = get_irg_frame_type(irg);
66 size_t n_compound = get_compound_n_members(frame_type);
69 if (n_compound_ret == 0)
72 for (i = 0; i < n_compound; ++i) {
73 ir_entity *member = get_compound_member(frame_type, i);
75 if (!is_parameter_entity(member))
78 /* increase parameter number since we added a new parameter in front */
79 num = get_entity_parameter_number(member);
80 if (num == IR_VA_START_PARAMETER_NUMBER)
82 set_entity_parameter_number(member, num + n_compound_ret);
87 * Creates a new lowered type for a method type with compound
88 * arguments. The new type is associated to the old one and returned.
90 static ir_type *lower_mtp(compound_call_lowering_flags flags, ir_type *mtp)
92 bool must_be_lowered = false;
102 if (!is_Method_type(mtp))
105 lowered = (ir_type*)pmap_get(lowered_mtps, mtp);
109 /* check if the type has to be lowered at all */
110 n_ress = get_method_n_ress(mtp);
111 for (i = 0; i < n_ress; ++i) {
112 ir_type *res_tp = get_method_res_type(mtp, i);
113 if (is_compound_type(res_tp)) {
114 must_be_lowered = true;
118 if (!must_be_lowered)
121 n_params = get_method_n_params(mtp);
122 results = ALLOCANZ(ir_type*, n_ress);
123 params = ALLOCANZ(ir_type*, n_params + n_ress);
127 /* add a hidden parameter in front for every compound result */
128 for (i = 0; i < n_ress; ++i) {
129 ir_type *res_tp = get_method_res_type(mtp, i);
131 if (is_compound_type(res_tp)) {
132 /* this compound will be allocated on callers stack and its
133 address will be transmitted as a hidden parameter. */
134 ir_type *ptr_tp = get_pointer_type(res_tp);
135 params[nn_params++] = ptr_tp;
136 if (flags & LF_RETURN_HIDDEN)
137 results[nn_ress++] = ptr_tp;
140 results[nn_ress++] = res_tp;
143 /* copy over parameter types */
144 for (i = 0; i < n_params; ++i) {
145 params[nn_params++] = get_method_param_type(mtp, i);
147 assert(nn_ress <= n_ress);
148 assert(nn_params <= n_params + n_ress);
150 /* create the new type */
151 lowered = new_d_type_method(nn_params, nn_ress, get_type_dbg_info(mtp));
152 lowered->attr.ma.has_compound_ret_parameter = true;
155 for (i = 0; i < nn_params; ++i)
156 set_method_param_type(lowered, i, params[i]);
157 for (i = 0; i < nn_ress; ++i)
158 set_method_res_type(lowered, i, results[i]);
160 set_method_variadicity(lowered, get_method_variadicity(mtp));
162 /* associate the lowered type with the original one for easier access */
163 set_method_calling_convention(lowered, get_method_calling_convention(mtp) | cc_compound_ret);
164 set_method_additional_properties(lowered, get_method_additional_properties(mtp));
166 set_lowered_type(mtp, lowered);
167 pmap_insert(lowered_mtps, mtp, lowered);
175 typedef struct cl_entry cl_entry;
177 cl_entry *next; /**< Pointer to the next entry. */
178 ir_node *call; /**< Pointer to the Call node. */
179 ir_node *copyb; /**< List of all CopyB nodes. */
183 * Walker environment for fix_args_and_collect_calls().
185 typedef struct wlk_env_t {
186 size_t arg_shift; /**< The Argument index shift for parameters. */
187 struct obstack obst; /**< An obstack to allocate the data on. */
188 cl_entry *cl_list; /**< The call list. */
189 pmap *dummy_map; /**< A map for finding the dummy arguments. */
190 compound_call_lowering_flags flags;
191 ir_type *lowered_mtp; /**< The lowered method type of the current irg if any. */
192 unsigned only_local_mem:1; /**< Set if only local memory access was found. */
193 unsigned changed:1; /**< Set if the current graph was changed. */
197 * Return the call list entry of a call node.
198 * If no entry exists yet, allocate one and enter the node into
199 * the call list of the environment.
201 * @param call A Call node.
202 * @param env The environment.
204 static cl_entry *get_Call_entry(ir_node *call, wlk_env *env)
206 cl_entry *res = (cl_entry*)get_irn_link(call);
208 res = OALLOC(&env->obst, cl_entry);
209 res->next = env->cl_list;
212 set_irn_link(call, res);
219 * Finds the base address of an address by skipping Sel's and address
222 * @param adr the address
223 * @param pEnt points to the base entity if any
225 static ir_node *find_base_adr(ir_node *ptr, ir_entity **pEnt)
227 ir_entity *ent = NULL;
228 assert(mode_is_reference(get_irn_mode(ptr)));
232 ent = get_Sel_entity(ptr);
233 ptr = get_Sel_ptr(ptr);
235 else if (is_Add(ptr)) {
236 ir_node *left = get_Add_left(ptr);
237 if (mode_is_reference(get_irn_mode(left)))
240 ptr = get_Add_right(ptr);
242 } else if (is_Sub(ptr)) {
243 ptr = get_Sub_left(ptr);
253 * Check if a given pointer represents non-local memory.
255 static void check_ptr(ir_node *ptr, wlk_env *env)
257 ir_storage_class_class_t sc;
260 /* still alias free */
261 ptr = find_base_adr(ptr, &ent);
262 sc = get_base_sc(classify_pointer(ptr, ent));
263 if (sc != ir_sc_localvar && sc != ir_sc_malloced) {
264 /* non-local memory access */
265 env->only_local_mem = 0;
270 * Returns non-zero if a Call is surely a self-recursive Call.
271 * Beware: if this functions returns 0, the call might be self-recursive!
273 static bool is_self_recursive_Call(const ir_node *call)
275 const ir_node *callee = get_Call_ptr(call);
277 if (is_SymConst_addr_ent(callee)) {
278 const ir_entity *ent = get_SymConst_entity(callee);
279 const ir_graph *irg = get_entity_irg(ent);
280 if (irg == get_irn_irg(call))
287 * Post walker: shift all parameter indexes
288 * and collect Calls with compound returns in the call list.
289 * If a non-alias free memory access is found, reset the alias free
292 static void fix_args_and_collect_calls(ir_node *n, void *ctx)
294 wlk_env *env = (wlk_env*)ctx;
298 switch (get_irn_opcode(n)) {
301 if (env->only_local_mem) {
302 ptr = get_irn_n(n, 1);
307 if (env->arg_shift > 0) {
308 ir_node *pred = get_Proj_pred(n);
309 ir_graph *irg = get_irn_irg(n);
311 /* Fix the argument numbers */
312 if (pred == get_irg_args(irg)) {
313 long pnr = get_Proj_proj(n);
314 set_Proj_proj(n, pnr + env->arg_shift);
322 if (! is_self_recursive_Call(n)) {
323 /* any non self recursive call might access global memory */
324 env->only_local_mem = 0;
327 ctp = get_Call_type(n);
328 /* check for compound returns */
329 for (i = 0, n_res = get_method_n_ress(ctp); i < n_res; ++i) {
330 if (is_compound_type(get_method_res_type(ctp, i))) {
332 * This is a call with a compound return. As the result
333 * might be ignored, we must put it in the list.
335 (void)get_Call_entry(n, env);
342 ir_node *src = get_CopyB_src(n);
343 if (env->only_local_mem) {
344 check_ptr(get_CopyB_src(n), env);
345 if (env->only_local_mem)
346 check_ptr(get_CopyB_dst(n), env);
348 /* check for compound returns */
350 ir_node *proj = get_Proj_pred(src);
351 if (is_Proj(proj) && get_Proj_proj(proj) == pn_Call_T_result) {
352 ir_node *call = get_Proj_pred(proj);
354 ctp = get_Call_type(call);
355 if (is_compound_type(get_method_res_type(ctp, get_Proj_proj(src)))) {
356 /* found a CopyB from compound Call result */
357 cl_entry *e = get_Call_entry(call, env);
358 set_irn_link(n, e->copyb);
373 * Returns non-zero if a node is a compound address
374 * of a frame-type entity.
376 * @param ft the frame type
377 * @param adr the node
379 static bool is_compound_address(ir_type *ft, ir_node *adr)
385 if (get_Sel_n_indexs(adr) != 0)
387 ent = get_Sel_entity(adr);
388 return get_entity_owner(ent) == ft;
391 /** A pair for the copy-return-optimization. */
392 typedef struct cr_pair {
393 ir_entity *ent; /**< the entity than can be removed from the frame */
394 ir_node *arg; /**< the argument that replaces the entities address */
398 * Post walker: fixes all entities addresses for the copy-return
401 * Note: We expect the length of the cr_pair array (i.e. number of compound
402 * return values) to be 1 (C, C++) in almost all cases, so ignore the
403 * linear search complexity here.
405 static void do_copy_return_opt(ir_node *n, void *ctx)
408 ir_entity *ent = get_Sel_entity(n);
409 cr_pair *arr = (cr_pair*)ctx;
412 for (i = 0, l = ARR_LEN(arr); i < l; ++i) {
413 if (ent == arr[i].ent) {
414 exchange(n, arr[i].arg);
422 * Return a Sel node that selects a dummy argument of type tp.
423 * Dummy arguments are only needed once and we use a map
425 * We could even assign all dummy arguments the same offset
426 * in the frame type ...
428 * @param irg the graph
429 * @param block the block where a newly create Sel should be placed
430 * @param tp the type of the dummy entity that should be create
431 * @param env the environment
433 static ir_node *get_dummy_sel(ir_graph *irg, ir_node *block, ir_type *tp,
439 /* use a map the check if we already create such an entity */
440 e = pmap_find(env->dummy_map, tp);
442 ent = (ir_entity*)e->value;
444 ir_type *ft = get_irg_frame_type(irg);
445 ident *dummy_id = id_unique("dummy.%u");
446 ent = new_entity(ft, dummy_id, tp);
447 pmap_insert(env->dummy_map, tp, ent);
449 if (get_type_state(ft) == layout_fixed) {
450 /* Fix the layout again */
451 panic("Fixed layout not implemented");
454 return new_r_simpleSel(block, get_irg_no_mem(irg), get_irg_frame(irg), ent);
458 * Add the hidden parameter from the CopyB node to the Call node.
460 * @param irg the graph
461 * @param n_com number of compound results (will be number of hidden parameters)
462 * @param ins in array to store the hidden parameters into
463 * @param entry the call list
464 * @param env the environment
466 static void add_hidden_param(ir_graph *irg, size_t n_com, ir_node **ins,
467 cl_entry *entry, wlk_env *env)
469 ir_node *p, *n, *mem, *blk;
473 for (p = entry->copyb; p; p = n) {
474 ir_node *src = get_CopyB_src(p);
475 size_t idx = get_Proj_proj(src);
476 n = (ir_node*)get_irn_link(p);
478 ins[idx] = get_CopyB_dst(p);
479 mem = get_CopyB_mem(p);
480 blk = get_nodes_block(p);
482 /* get rid of the CopyB */
483 turn_into_tuple(p, pn_CopyB_max+1);
484 set_Tuple_pred(p, pn_CopyB_M, mem);
485 set_Tuple_pred(p, pn_CopyB_X_regular, new_r_Jmp(blk));
486 set_Tuple_pred(p, pn_CopyB_X_except, new_r_Bad(irg, mode_X));
490 /* now create dummy entities for function with ignored return value */
491 if (n_args < n_com) {
492 ir_type *ctp = get_Call_type(entry->call);
496 if (is_lowered_type(ctp))
497 ctp = get_associated_type(ctp);
499 for (j = i = 0; i < get_method_n_ress(ctp); ++i) {
500 ir_type *rtp = get_method_res_type(ctp, i);
501 if (is_compound_type(rtp)) {
503 ins[j] = get_dummy_sel(irg, get_nodes_block(entry->call), rtp, env);
511 * Fix all calls on a call list by adding hidden parameters.
513 * @param irg the graph
514 * @param env the environment
516 static void fix_call_list(ir_graph *irg, wlk_env *env)
519 ir_node *call, **new_in;
520 ir_type *ctp, *lowered_mtp;
521 size_t i, n_res, n_params, n_com, pos;
523 new_in = NEW_ARR_F(ir_node *, 0);
524 for (p = env->cl_list; p; p = p->next) {
526 ctp = get_Call_type(call);
527 lowered_mtp = lower_mtp(env->flags, ctp);
528 set_Call_type(call, lowered_mtp);
530 n_params = get_Call_n_params(call);
533 for (i = 0, n_res = get_method_n_ress(ctp); i < n_res; ++i) {
534 if (is_compound_type(get_method_res_type(ctp, i)))
538 ARR_RESIZE(ir_node *, new_in, n_params + n_com + pos);
539 memset(new_in, 0, sizeof(*new_in) * (n_params + n_com + pos));
540 add_hidden_param(irg, n_com, &new_in[pos], p, env);
542 /* copy all other parameters */
543 for (i = 0; i < n_params; ++i)
544 new_in[pos++] = get_Call_param(call, i);
545 new_in[0] = get_Call_mem(call);
546 new_in[1] = get_Call_ptr(call);
548 set_irn_in(call, n_params + n_com + 2, new_in);
553 * Transform a graph. If it has compound parameter returns,
554 * remove them and use the hidden parameter instead.
555 * If it calls methods with compound parameter returns, add hidden
558 * @param irg the graph to transform
560 static void transform_irg(compound_call_lowering_flags flags, ir_graph *irg)
562 ir_entity *ent = get_irg_entity(irg);
563 ir_type *mtp, *lowered_mtp, *tp, *ft;
564 size_t i, j, k, n_ress = 0, n_ret_com = 0;
566 ir_node **new_in, *ret, *endbl, *bl, *mem, *copy;
570 mtp = get_entity_type(ent);
572 /* calculate the number of compound returns */
573 n_ress = get_method_n_ress(mtp);
574 for (n_ret_com = i = 0; i < n_ress; ++i) {
575 tp = get_method_res_type(mtp, i);
577 if (is_compound_type(tp))
581 fix_parameter_entities(irg, n_ret_com);
584 /* much easier if we have only one return */
585 normalize_one_return(irg);
587 /* This graph has a compound argument. Create a new type */
588 lowered_mtp = lower_mtp(flags, mtp);
589 set_entity_type(ent, lowered_mtp);
591 /* hidden arguments are added first */
592 env.arg_shift = n_ret_com;
594 /* we must only search for calls */
598 obstack_init(&env.obst);
600 env.dummy_map = pmap_create_ex(8);
602 env.lowered_mtp = lowered_mtp;
603 env.only_local_mem = 1;
606 /* scan the code, fix argument numbers and collect calls. */
607 irg_walk_graph(irg, firm_clear_link, fix_args_and_collect_calls, &env);
611 fix_call_list(irg, &env);
618 /* STEP 1: find the return. This is simple, we have normalized the graph. */
619 endbl = get_irg_end_block(irg);
621 for (idx = get_Block_n_cfgpreds(endbl) - 1; idx >= 0; --idx) {
622 ir_node *pred = get_Block_cfgpred(endbl, idx);
624 if (is_Return(pred)) {
630 /* in case of infinite loops, there might be no return */
633 * Now fix the Return node of the current graph.
638 * STEP 2: fix it. For all compound return values add a CopyB,
639 * all others are copied.
641 NEW_ARR_A(ir_node *, new_in, n_ress + 1);
643 bl = get_nodes_block(ret);
644 mem = get_Return_mem(ret);
646 ft = get_irg_frame_type(irg);
647 NEW_ARR_A(cr_pair, cr_opt, n_ret_com);
649 for (j = 1, i = k = 0; i < n_ress; ++i) {
650 ir_node *pred = get_Return_res(ret, i);
651 tp = get_method_res_type(mtp, i);
653 if (is_compound_type(tp)) {
654 ir_node *arg = get_irg_args(irg);
655 arg = new_r_Proj(arg, mode_P_data, k);
658 if (is_Unknown(pred)) {
659 /* The Return(Unknown) is the Firm construct for a
660 * missing return. Do nothing. */
663 * Sorrily detecting that copy-return is possible isn't
664 * that simple. We must check, that the hidden address
665 * is alias free during the whole function.
666 * A simple heuristic: all Loads/Stores inside
667 * the function access only local frame.
669 if (env.only_local_mem && is_compound_address(ft, pred)) {
670 /* we can do the copy-return optimization here */
671 cr_opt[n_cr_opt].ent = get_Sel_entity(pred);
672 cr_opt[n_cr_opt].arg = arg;
674 } else { /* copy-return optimization is impossible, do the copy. */
682 mem = new_r_Proj(copy, mode_M, pn_CopyB_M);
685 if (flags & LF_RETURN_HIDDEN) {
689 } else { /* scalar return value */
694 /* replace the in of the Return */
696 set_irn_in(ret, j, new_in);
702 irg_walk_graph(irg, NULL, do_copy_return_opt, cr_opt);
704 for (c = 0, n = ARR_LEN(cr_opt); c < n; ++c) {
705 free_entity(cr_opt[c].ent);
711 pmap_destroy(env.dummy_map);
712 obstack_free(&env.obst, NULL);
715 static void lower_method_types(type_or_ent tore, void *env)
717 const compound_call_lowering_flags *flags
718 = (const compound_call_lowering_flags*)env;
720 /* fix method entities */
721 if (is_entity(tore.ent)) {
722 ir_entity *ent = tore.ent;
723 ir_type *tp = get_entity_type(ent);
724 ir_type *lowered = lower_mtp(*flags, tp);
725 set_entity_type(ent, lowered);
727 ir_type *tp = tore.typ;
729 /* fix pointer to methods */
730 if (is_Pointer_type(tp)) {
731 ir_type *points_to = get_pointer_points_to_type(tp);
732 ir_type *lowered_points_to = lower_mtp(*flags, points_to);
733 set_pointer_points_to_type(tp, lowered_points_to);
738 void lower_calls_with_compounds(compound_call_lowering_flags flags)
742 pointer_types = pmap_create();
743 lowered_mtps = pmap_create();
745 /* first step: Transform all graphs */
746 for (i = 0, n = get_irp_n_irgs(); i < n; ++i) {
747 ir_graph *irg = get_irp_irg(i);
748 transform_irg(flags, irg);
751 /* second step: Lower all method types of visible entities */
752 type_walk(NULL, lower_method_types, &flags);
754 pmap_destroy(lowered_mtps);
755 pmap_destroy(pointer_types);