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);
64 * Creates a new lowered type for a method type with compound
65 * arguments. The new type is associated to the old one and returned.
67 static ir_type *lower_mtp(compound_call_lowering_flags flags, ir_type *mtp)
69 bool must_be_lowered = false;
79 if (!is_Method_type(mtp))
82 lowered = (ir_type*)pmap_get(lowered_mtps, mtp);
86 /* check if the type has to be lowered at all */
87 n_ress = get_method_n_ress(mtp);
88 for (i = 0; i < n_ress; ++i) {
89 ir_type *res_tp = get_method_res_type(mtp, i);
90 if (is_compound_type(res_tp)) {
91 must_be_lowered = true;
98 n_params = get_method_n_params(mtp);
99 results = ALLOCANZ(ir_type*, n_ress);
100 params = ALLOCANZ(ir_type*, n_params + n_ress);
104 /* add a hidden parameter in front for every compound result */
105 for (i = 0; i < n_ress; ++i) {
106 ir_type *res_tp = get_method_res_type(mtp, i);
108 if (is_compound_type(res_tp)) {
109 /* this compound will be allocated on callers stack and its
110 address will be transmitted as a hidden parameter. */
111 ir_type *ptr_tp = get_pointer_type(res_tp);
112 params[nn_params++] = ptr_tp;
113 if (flags & LF_RETURN_HIDDEN)
114 results[nn_ress++] = ptr_tp;
117 results[nn_ress++] = res_tp;
120 /* copy over parameter types */
121 for (i = 0; i < n_params; ++i) {
122 params[nn_params++] = get_method_param_type(mtp, i);
124 assert(nn_ress <= n_ress);
125 assert(nn_params <= n_params + n_ress);
127 /* create the new type */
128 lowered = new_d_type_method(nn_params, nn_ress, get_type_dbg_info(mtp));
131 for (i = 0; i < nn_params; ++i)
132 set_method_param_type(lowered, i, params[i]);
133 for (i = 0; i < nn_ress; ++i)
134 set_method_res_type(lowered, i, results[i]);
136 set_method_variadicity(lowered, get_method_variadicity(mtp));
138 /* associate the lowered type with the original one for easier access */
139 set_method_calling_convention(lowered, get_method_calling_convention(mtp) | cc_compound_ret);
141 set_lowered_type(mtp, lowered);
142 pmap_insert(lowered_mtps, mtp, lowered);
150 typedef struct cl_entry cl_entry;
152 cl_entry *next; /**< Pointer to the next entry. */
153 ir_node *call; /**< Pointer to the Call node. */
154 ir_node *copyb; /**< List of all CopyB nodes. */
158 * Walker environment for fix_args_and_collect_calls().
160 typedef struct wlk_env_t {
161 size_t arg_shift; /**< The Argument index shift for parameters. */
162 struct obstack obst; /**< An obstack to allocate the data on. */
163 cl_entry *cl_list; /**< The call list. */
164 pmap *dummy_map; /**< A map for finding the dummy arguments. */
165 compound_call_lowering_flags flags;
166 ir_type *lowered_mtp; /**< The lowered method type of the current irg if any. */
167 ir_type *value_params; /**< The value params type if any. */
168 unsigned only_local_mem:1; /**< Set if only local memory access was found. */
169 unsigned changed:1; /**< Set if the current graph was changed. */
173 * Return the call list entry of a call node.
174 * If no entry exists yet, allocate one and enter the node into
175 * the call list of the environment.
177 * @param call A Call node.
178 * @param env The environment.
180 static cl_entry *get_Call_entry(ir_node *call, wlk_env *env)
182 cl_entry *res = (cl_entry*)get_irn_link(call);
184 res = OALLOC(&env->obst, cl_entry);
185 res->next = env->cl_list;
188 set_irn_link(call, res);
195 * Finds the base address of an address by skipping Sel's and address
198 * @param adr the address
199 * @param pEnt points to the base entity if any
201 static ir_node *find_base_adr(ir_node *ptr, ir_entity **pEnt)
203 ir_entity *ent = NULL;
204 assert(mode_is_reference(get_irn_mode(ptr)));
208 ent = get_Sel_entity(ptr);
209 ptr = get_Sel_ptr(ptr);
211 else if (is_Add(ptr)) {
212 ir_node *left = get_Add_left(ptr);
213 if (mode_is_reference(get_irn_mode(left)))
216 ptr = get_Add_right(ptr);
218 } else if (is_Sub(ptr)) {
219 ptr = get_Sub_left(ptr);
229 * Check if a given pointer represents non-local memory.
231 static void check_ptr(ir_node *ptr, wlk_env *env)
233 ir_storage_class_class_t sc;
236 /* still alias free */
237 ptr = find_base_adr(ptr, &ent);
238 sc = get_base_sc(classify_pointer(ptr, ent));
239 if (sc != ir_sc_localvar && sc != ir_sc_malloced) {
240 /* non-local memory access */
241 env->only_local_mem = 0;
246 * Returns non-zero if a Call is surely a self-recursive Call.
247 * Beware: if this functions returns 0, the call might be self-recursive!
249 static bool is_self_recursive_Call(const ir_node *call)
251 const ir_node *callee = get_Call_ptr(call);
253 if (is_SymConst_addr_ent(callee)) {
254 const ir_entity *ent = get_SymConst_entity(callee);
255 const ir_graph *irg = get_entity_irg(ent);
256 if (irg == get_irn_irg(call))
263 * Post walker: shift all parameter indexes
264 * and collect Calls with compound returns in the call list.
265 * If a non-alias free memory access is found, reset the alias free
268 static void fix_args_and_collect_calls(ir_node *n, void *ctx)
270 wlk_env *env = (wlk_env*)ctx;
274 switch (get_irn_opcode(n)) {
276 if (env->lowered_mtp != NULL && env->value_params != NULL) {
277 ir_entity *ent = get_Sel_entity(n);
279 if (get_entity_owner(ent) == env->value_params) {
280 size_t pos = get_struct_member_index(env->value_params, ent) + env->arg_shift;
283 new_ent = get_method_value_param_ent(env->lowered_mtp, pos);
284 set_entity_ident(new_ent, get_entity_ident(ent));
285 set_Sel_entity(n, new_ent);
291 if (env->only_local_mem) {
292 ptr = get_irn_n(n, 1);
297 if (env->arg_shift > 0) {
298 ir_node *pred = get_Proj_pred(n);
299 ir_graph *irg = get_irn_irg(n);
301 /* Fix the argument numbers */
302 if (pred == get_irg_args(irg)) {
303 long pnr = get_Proj_proj(n);
304 set_Proj_proj(n, pnr + env->arg_shift);
312 if (! is_self_recursive_Call(n)) {
313 /* any non self recursive call might access global memory */
314 env->only_local_mem = 0;
317 ctp = get_Call_type(n);
318 /* check for compound returns */
319 for (i = 0, n_res = get_method_n_ress(ctp); i < n_res; ++i) {
320 if (is_compound_type(get_method_res_type(ctp, i))) {
322 * This is a call with a compound return. As the result
323 * might be ignored, we must put it in the list.
325 (void)get_Call_entry(n, env);
332 ir_node *src = get_CopyB_src(n);
333 if (env->only_local_mem) {
334 check_ptr(get_CopyB_src(n), env);
335 if (env->only_local_mem)
336 check_ptr(get_CopyB_dst(n), env);
338 /* check for compound returns */
340 ir_node *proj = get_Proj_pred(src);
341 if (is_Proj(proj) && get_Proj_proj(proj) == pn_Call_T_result) {
342 ir_node *call = get_Proj_pred(proj);
344 ctp = get_Call_type(call);
345 if (is_compound_type(get_method_res_type(ctp, get_Proj_proj(src)))) {
346 /* found a CopyB from compound Call result */
347 cl_entry *e = get_Call_entry(call, env);
348 set_irn_link(n, e->copyb);
363 * Returns non-zero if a node is a compound address
364 * of a frame-type entity.
366 * @param ft the frame type
367 * @param adr the node
369 static bool is_compound_address(ir_type *ft, ir_node *adr)
375 if (get_Sel_n_indexs(adr) != 0)
377 ent = get_Sel_entity(adr);
378 return get_entity_owner(ent) == ft;
381 /** A pair for the copy-return-optimization. */
382 typedef struct cr_pair {
383 ir_entity *ent; /**< the entity than can be removed from the frame */
384 ir_node *arg; /**< the argument that replaces the entities address */
388 * Post walker: fixes all entities addresses for the copy-return
391 * Note: We expect the length of the cr_pair array (i.e. number of compound
392 * return values) to be 1 (C, C++) in almost all cases, so ignore the
393 * linear search complexity here.
395 static void do_copy_return_opt(ir_node *n, void *ctx)
398 ir_entity *ent = get_Sel_entity(n);
399 cr_pair *arr = (cr_pair*)ctx;
402 for (i = 0, l = ARR_LEN(arr); i < l; ++i) {
403 if (ent == arr[i].ent) {
404 exchange(n, arr[i].arg);
412 * Return a Sel node that selects a dummy argument of type tp.
413 * Dummy arguments are only needed once and we use a map
415 * We could even assign all dummy arguments the same offset
416 * in the frame type ...
418 * @param irg the graph
419 * @param block the block where a newly create Sel should be placed
420 * @param tp the type of the dummy entity that should be create
421 * @param env the environment
423 static ir_node *get_dummy_sel(ir_graph *irg, ir_node *block, ir_type *tp,
429 /* use a map the check if we already create such an entity */
430 e = pmap_find(env->dummy_map, tp);
432 ent = (ir_entity*)e->value;
434 ir_type *ft = get_irg_frame_type(irg);
435 ident *dummy_id = id_unique("dummy.%u");
436 ent = new_entity(ft, dummy_id, tp);
437 pmap_insert(env->dummy_map, tp, ent);
439 if (get_type_state(ft) == layout_fixed) {
440 /* Fix the layout again */
441 panic("Fixed layout not implemented");
444 return new_r_simpleSel(block, get_irg_no_mem(irg), get_irg_frame(irg), ent);
448 * Add the hidden parameter from the CopyB node to the Call node.
450 * @param irg the graph
451 * @param n_com number of compound results (will be number of hidden parameters)
452 * @param ins in array to store the hidden parameters into
453 * @param entry the call list
454 * @param env the environment
456 static void add_hidden_param(ir_graph *irg, size_t n_com, ir_node **ins,
457 cl_entry *entry, wlk_env *env)
459 ir_node *p, *n, *mem, *blk;
463 for (p = entry->copyb; p; p = n) {
464 ir_node *src = get_CopyB_src(p);
465 size_t idx = get_Proj_proj(src);
466 n = (ir_node*)get_irn_link(p);
468 ins[idx] = get_CopyB_dst(p);
469 mem = get_CopyB_mem(p);
470 blk = get_nodes_block(p);
472 /* get rid of the CopyB */
473 turn_into_tuple(p, pn_CopyB_max+1);
474 set_Tuple_pred(p, pn_CopyB_M, mem);
475 set_Tuple_pred(p, pn_CopyB_X_regular, new_r_Jmp(blk));
476 set_Tuple_pred(p, pn_CopyB_X_except, new_r_Bad(irg, mode_X));
480 /* now create dummy entities for function with ignored return value */
481 if (n_args < n_com) {
482 ir_type *ctp = get_Call_type(entry->call);
486 if (is_lowered_type(ctp))
487 ctp = get_associated_type(ctp);
489 for (j = i = 0; i < get_method_n_ress(ctp); ++i) {
490 ir_type *rtp = get_method_res_type(ctp, i);
491 if (is_compound_type(rtp)) {
493 ins[j] = get_dummy_sel(irg, get_nodes_block(entry->call), rtp, env);
501 * Fix all calls on a call list by adding hidden parameters.
503 * @param irg the graph
504 * @param env the environment
506 static void fix_call_list(ir_graph *irg, wlk_env *env)
509 ir_node *call, **new_in;
510 ir_type *ctp, *lowered_mtp;
511 size_t i, n_res, n_params, n_com, pos;
513 new_in = NEW_ARR_F(ir_node *, 0);
514 for (p = env->cl_list; p; p = p->next) {
516 ctp = get_Call_type(call);
517 lowered_mtp = lower_mtp(env->flags, ctp);
518 set_Call_type(call, lowered_mtp);
520 n_params = get_Call_n_params(call);
523 for (i = 0, n_res = get_method_n_ress(ctp); i < n_res; ++i) {
524 if (is_compound_type(get_method_res_type(ctp, i)))
528 ARR_RESIZE(ir_node *, new_in, n_params + n_com + pos);
529 memset(new_in, 0, sizeof(*new_in) * (n_params + n_com + pos));
530 add_hidden_param(irg, n_com, &new_in[pos], p, env);
532 /* copy all other parameters */
533 for (i = 0; i < n_params; ++i)
534 new_in[pos++] = get_Call_param(call, i);
535 new_in[0] = get_Call_mem(call);
536 new_in[1] = get_Call_ptr(call);
538 set_irn_in(call, n_params + n_com + 2, new_in);
543 * Transform a graph. If it has compound parameter returns,
544 * remove them and use the hidden parameter instead.
545 * If it calls methods with compound parameter returns, add hidden
548 * @param irg the graph to transform
550 static void transform_irg(compound_call_lowering_flags flags, ir_graph *irg)
552 ir_entity *ent = get_irg_entity(irg);
553 ir_type *mtp, *lowered_mtp, *tp, *ft;
554 size_t i, j, k, n_ress = 0, n_ret_com = 0;
556 ir_node **new_in, *ret, *endbl, *bl, *mem, *copy;
560 mtp = get_entity_type(ent);
562 /* calculate the number of compound returns */
563 n_ress = get_method_n_ress(mtp);
564 for (n_ret_com = i = 0; i < n_ress; ++i) {
565 tp = get_method_res_type(mtp, i);
567 if (is_compound_type(tp))
572 /* much easier if we have only one return */
573 normalize_one_return(irg);
575 /* This graph has a compound argument. Create a new type */
576 lowered_mtp = lower_mtp(flags, mtp);
577 set_entity_type(ent, lowered_mtp);
579 /* hidden arguments are added first */
580 env.arg_shift = n_ret_com;
582 /* we must only search for calls */
586 obstack_init(&env.obst);
588 env.dummy_map = pmap_create_ex(8);
590 env.lowered_mtp = lowered_mtp;
591 env.value_params = get_method_value_param_type(mtp);
592 env.only_local_mem = 1;
595 /* scan the code, fix argument numbers and collect calls. */
596 irg_walk_graph(irg, firm_clear_link, fix_args_and_collect_calls, &env);
600 fix_call_list(irg, &env);
607 /* STEP 1: find the return. This is simple, we have normalized the graph. */
608 endbl = get_irg_end_block(irg);
610 for (idx = get_Block_n_cfgpreds(endbl) - 1; idx >= 0; --idx) {
611 ir_node *pred = get_Block_cfgpred(endbl, idx);
613 if (is_Return(pred)) {
619 /* in case of infinite loops, there might be no return */
622 * Now fix the Return node of the current graph.
627 * STEP 2: fix it. For all compound return values add a CopyB,
628 * all others are copied.
630 NEW_ARR_A(ir_node *, new_in, n_ress + 1);
632 bl = get_nodes_block(ret);
633 mem = get_Return_mem(ret);
635 ft = get_irg_frame_type(irg);
636 NEW_ARR_A(cr_pair, cr_opt, n_ret_com);
638 for (j = 1, i = k = 0; i < n_ress; ++i) {
639 ir_node *pred = get_Return_res(ret, i);
640 tp = get_method_res_type(mtp, i);
642 if (is_compound_type(tp)) {
643 ir_node *arg = get_irg_args(irg);
644 arg = new_r_Proj(arg, mode_P_data, k);
647 if (is_Unknown(pred)) {
648 /* The Return(Unknown) is the Firm construct for a
649 * missing return. Do nothing. */
652 * Sorrily detecting that copy-return is possible isn't
653 * that simple. We must check, that the hidden address
654 * is alias free during the whole function.
655 * A simple heuristic: all Loads/Stores inside
656 * the function access only local frame.
658 if (env.only_local_mem && is_compound_address(ft, pred)) {
659 /* we can do the copy-return optimization here */
660 cr_opt[n_cr_opt].ent = get_Sel_entity(pred);
661 cr_opt[n_cr_opt].arg = arg;
663 } else { /* copy-return optimization is impossible, do the copy. */
671 mem = new_r_Proj(copy, mode_M, pn_CopyB_M);
674 if (flags & LF_RETURN_HIDDEN) {
678 } else { /* scalar return value */
683 /* replace the in of the Return */
685 set_irn_in(ret, j, new_in);
691 irg_walk_graph(irg, NULL, do_copy_return_opt, cr_opt);
693 for (c = 0, n = ARR_LEN(cr_opt); c < n; ++c) {
694 free_entity(cr_opt[c].ent);
700 pmap_destroy(env.dummy_map);
701 obstack_free(&env.obst, NULL);
704 static void lower_method_types(type_or_ent tore, void *env)
706 const compound_call_lowering_flags *flags
707 = (const compound_call_lowering_flags*)env;
709 /* fix method entities */
710 if (is_entity(tore.ent)) {
711 ir_entity *ent = tore.ent;
712 ir_type *tp = get_entity_type(ent);
713 ir_type *lowered = lower_mtp(*flags, tp);
714 set_entity_type(ent, lowered);
716 ir_type *tp = tore.typ;
718 /* fix pointer to methods */
719 if (is_Pointer_type(tp)) {
720 ir_type *points_to = get_pointer_points_to_type(tp);
721 ir_type *lowered_points_to = lower_mtp(*flags, points_to);
722 set_pointer_points_to_type(tp, lowered_points_to);
727 void lower_calls_with_compounds(compound_call_lowering_flags flags)
731 pointer_types = pmap_create();
732 lowered_mtps = pmap_create();
734 /* first step: Transform all graphs */
735 for (i = 0, n = get_irp_n_irgs(); i < n; ++i) {
736 ir_graph *irg = get_irp_irg(i);
737 transform_irg(flags, irg);
740 /* second step: Lower all method types of visible entities */
741 type_walk(NULL, lower_method_types, &flags);
743 pmap_destroy(lowered_mtps);
744 pmap_destroy(pointer_types);