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 set_entity_parameter_number(member, num + n_compound_ret);
85 * Creates a new lowered type for a method type with compound
86 * arguments. The new type is associated to the old one and returned.
88 static ir_type *lower_mtp(compound_call_lowering_flags flags, ir_type *mtp)
90 bool must_be_lowered = false;
100 if (!is_Method_type(mtp))
103 lowered = (ir_type*)pmap_get(lowered_mtps, mtp);
107 /* check if the type has to be lowered at all */
108 n_ress = get_method_n_ress(mtp);
109 for (i = 0; i < n_ress; ++i) {
110 ir_type *res_tp = get_method_res_type(mtp, i);
111 if (is_compound_type(res_tp)) {
112 must_be_lowered = true;
116 if (!must_be_lowered)
119 n_params = get_method_n_params(mtp);
120 results = ALLOCANZ(ir_type*, n_ress);
121 params = ALLOCANZ(ir_type*, n_params + n_ress);
125 /* add a hidden parameter in front for every compound result */
126 for (i = 0; i < n_ress; ++i) {
127 ir_type *res_tp = get_method_res_type(mtp, i);
129 if (is_compound_type(res_tp)) {
130 /* this compound will be allocated on callers stack and its
131 address will be transmitted as a hidden parameter. */
132 ir_type *ptr_tp = get_pointer_type(res_tp);
133 params[nn_params++] = ptr_tp;
134 if (flags & LF_RETURN_HIDDEN)
135 results[nn_ress++] = ptr_tp;
138 results[nn_ress++] = res_tp;
141 /* copy over parameter types */
142 for (i = 0; i < n_params; ++i) {
143 params[nn_params++] = get_method_param_type(mtp, i);
145 assert(nn_ress <= n_ress);
146 assert(nn_params <= n_params + n_ress);
148 /* create the new type */
149 lowered = new_d_type_method(nn_params, nn_ress, get_type_dbg_info(mtp));
152 for (i = 0; i < nn_params; ++i)
153 set_method_param_type(lowered, i, params[i]);
154 for (i = 0; i < nn_ress; ++i)
155 set_method_res_type(lowered, i, results[i]);
157 set_method_variadicity(lowered, get_method_variadicity(mtp));
159 /* associate the lowered type with the original one for easier access */
160 set_method_calling_convention(lowered, get_method_calling_convention(mtp) | cc_compound_ret);
161 set_method_additional_properties(lowered, get_method_additional_properties(mtp));
163 set_lowered_type(mtp, lowered);
164 pmap_insert(lowered_mtps, mtp, lowered);
172 typedef struct cl_entry cl_entry;
174 cl_entry *next; /**< Pointer to the next entry. */
175 ir_node *call; /**< Pointer to the Call node. */
176 ir_node *copyb; /**< List of all CopyB nodes. */
180 * Walker environment for fix_args_and_collect_calls().
182 typedef struct wlk_env_t {
183 size_t arg_shift; /**< The Argument index shift for parameters. */
184 struct obstack obst; /**< An obstack to allocate the data on. */
185 cl_entry *cl_list; /**< The call list. */
186 pmap *dummy_map; /**< A map for finding the dummy arguments. */
187 compound_call_lowering_flags flags;
188 ir_type *lowered_mtp; /**< The lowered method type of the current irg if any. */
189 unsigned only_local_mem:1; /**< Set if only local memory access was found. */
190 unsigned changed:1; /**< Set if the current graph was changed. */
194 * Return the call list entry of a call node.
195 * If no entry exists yet, allocate one and enter the node into
196 * the call list of the environment.
198 * @param call A Call node.
199 * @param env The environment.
201 static cl_entry *get_Call_entry(ir_node *call, wlk_env *env)
203 cl_entry *res = (cl_entry*)get_irn_link(call);
205 res = OALLOC(&env->obst, cl_entry);
206 res->next = env->cl_list;
209 set_irn_link(call, res);
216 * Finds the base address of an address by skipping Sel's and address
219 * @param adr the address
220 * @param pEnt points to the base entity if any
222 static ir_node *find_base_adr(ir_node *ptr, ir_entity **pEnt)
224 ir_entity *ent = NULL;
225 assert(mode_is_reference(get_irn_mode(ptr)));
229 ent = get_Sel_entity(ptr);
230 ptr = get_Sel_ptr(ptr);
232 else if (is_Add(ptr)) {
233 ir_node *left = get_Add_left(ptr);
234 if (mode_is_reference(get_irn_mode(left)))
237 ptr = get_Add_right(ptr);
239 } else if (is_Sub(ptr)) {
240 ptr = get_Sub_left(ptr);
250 * Check if a given pointer represents non-local memory.
252 static void check_ptr(ir_node *ptr, wlk_env *env)
254 ir_storage_class_class_t sc;
257 /* still alias free */
258 ptr = find_base_adr(ptr, &ent);
259 sc = get_base_sc(classify_pointer(ptr, ent));
260 if (sc != ir_sc_localvar && sc != ir_sc_malloced) {
261 /* non-local memory access */
262 env->only_local_mem = 0;
267 * Returns non-zero if a Call is surely a self-recursive Call.
268 * Beware: if this functions returns 0, the call might be self-recursive!
270 static bool is_self_recursive_Call(const ir_node *call)
272 const ir_node *callee = get_Call_ptr(call);
274 if (is_SymConst_addr_ent(callee)) {
275 const ir_entity *ent = get_SymConst_entity(callee);
276 const ir_graph *irg = get_entity_irg(ent);
277 if (irg == get_irn_irg(call))
284 * Post walker: shift all parameter indexes
285 * and collect Calls with compound returns in the call list.
286 * If a non-alias free memory access is found, reset the alias free
289 static void fix_args_and_collect_calls(ir_node *n, void *ctx)
291 wlk_env *env = (wlk_env*)ctx;
295 switch (get_irn_opcode(n)) {
298 if (env->only_local_mem) {
299 ptr = get_irn_n(n, 1);
304 if (env->arg_shift > 0) {
305 ir_node *pred = get_Proj_pred(n);
306 ir_graph *irg = get_irn_irg(n);
308 /* Fix the argument numbers */
309 if (pred == get_irg_args(irg)) {
310 long pnr = get_Proj_proj(n);
311 set_Proj_proj(n, pnr + env->arg_shift);
319 if (! is_self_recursive_Call(n)) {
320 /* any non self recursive call might access global memory */
321 env->only_local_mem = 0;
324 ctp = get_Call_type(n);
325 /* check for compound returns */
326 for (i = 0, n_res = get_method_n_ress(ctp); i < n_res; ++i) {
327 if (is_compound_type(get_method_res_type(ctp, i))) {
329 * This is a call with a compound return. As the result
330 * might be ignored, we must put it in the list.
332 (void)get_Call_entry(n, env);
339 ir_node *src = get_CopyB_src(n);
340 if (env->only_local_mem) {
341 check_ptr(get_CopyB_src(n), env);
342 if (env->only_local_mem)
343 check_ptr(get_CopyB_dst(n), env);
345 /* check for compound returns */
347 ir_node *proj = get_Proj_pred(src);
348 if (is_Proj(proj) && get_Proj_proj(proj) == pn_Call_T_result) {
349 ir_node *call = get_Proj_pred(proj);
351 ctp = get_Call_type(call);
352 if (is_compound_type(get_method_res_type(ctp, get_Proj_proj(src)))) {
353 /* found a CopyB from compound Call result */
354 cl_entry *e = get_Call_entry(call, env);
355 set_irn_link(n, e->copyb);
370 * Returns non-zero if a node is a compound address
371 * of a frame-type entity.
373 * @param ft the frame type
374 * @param adr the node
376 static bool is_compound_address(ir_type *ft, ir_node *adr)
382 if (get_Sel_n_indexs(adr) != 0)
384 ent = get_Sel_entity(adr);
385 return get_entity_owner(ent) == ft;
388 /** A pair for the copy-return-optimization. */
389 typedef struct cr_pair {
390 ir_entity *ent; /**< the entity than can be removed from the frame */
391 ir_node *arg; /**< the argument that replaces the entities address */
395 * Post walker: fixes all entities addresses for the copy-return
398 * Note: We expect the length of the cr_pair array (i.e. number of compound
399 * return values) to be 1 (C, C++) in almost all cases, so ignore the
400 * linear search complexity here.
402 static void do_copy_return_opt(ir_node *n, void *ctx)
405 ir_entity *ent = get_Sel_entity(n);
406 cr_pair *arr = (cr_pair*)ctx;
409 for (i = 0, l = ARR_LEN(arr); i < l; ++i) {
410 if (ent == arr[i].ent) {
411 exchange(n, arr[i].arg);
419 * Return a Sel node that selects a dummy argument of type tp.
420 * Dummy arguments are only needed once and we use a map
422 * We could even assign all dummy arguments the same offset
423 * in the frame type ...
425 * @param irg the graph
426 * @param block the block where a newly create Sel should be placed
427 * @param tp the type of the dummy entity that should be create
428 * @param env the environment
430 static ir_node *get_dummy_sel(ir_graph *irg, ir_node *block, ir_type *tp,
436 /* use a map the check if we already create such an entity */
437 e = pmap_find(env->dummy_map, tp);
439 ent = (ir_entity*)e->value;
441 ir_type *ft = get_irg_frame_type(irg);
442 ident *dummy_id = id_unique("dummy.%u");
443 ent = new_entity(ft, dummy_id, tp);
444 pmap_insert(env->dummy_map, tp, ent);
446 if (get_type_state(ft) == layout_fixed) {
447 /* Fix the layout again */
448 panic("Fixed layout not implemented");
451 return new_r_simpleSel(block, get_irg_no_mem(irg), get_irg_frame(irg), ent);
455 * Add the hidden parameter from the CopyB node to the Call node.
457 * @param irg the graph
458 * @param n_com number of compound results (will be number of hidden parameters)
459 * @param ins in array to store the hidden parameters into
460 * @param entry the call list
461 * @param env the environment
463 static void add_hidden_param(ir_graph *irg, size_t n_com, ir_node **ins,
464 cl_entry *entry, wlk_env *env)
466 ir_node *p, *n, *mem, *blk;
470 for (p = entry->copyb; p; p = n) {
471 ir_node *src = get_CopyB_src(p);
472 size_t idx = get_Proj_proj(src);
473 n = (ir_node*)get_irn_link(p);
475 ins[idx] = get_CopyB_dst(p);
476 mem = get_CopyB_mem(p);
477 blk = get_nodes_block(p);
479 /* get rid of the CopyB */
480 turn_into_tuple(p, pn_CopyB_max+1);
481 set_Tuple_pred(p, pn_CopyB_M, mem);
482 set_Tuple_pred(p, pn_CopyB_X_regular, new_r_Jmp(blk));
483 set_Tuple_pred(p, pn_CopyB_X_except, new_r_Bad(irg, mode_X));
487 /* now create dummy entities for function with ignored return value */
488 if (n_args < n_com) {
489 ir_type *ctp = get_Call_type(entry->call);
493 if (is_lowered_type(ctp))
494 ctp = get_associated_type(ctp);
496 for (j = i = 0; i < get_method_n_ress(ctp); ++i) {
497 ir_type *rtp = get_method_res_type(ctp, i);
498 if (is_compound_type(rtp)) {
500 ins[j] = get_dummy_sel(irg, get_nodes_block(entry->call), rtp, env);
508 * Fix all calls on a call list by adding hidden parameters.
510 * @param irg the graph
511 * @param env the environment
513 static void fix_call_list(ir_graph *irg, wlk_env *env)
516 ir_node *call, **new_in;
517 ir_type *ctp, *lowered_mtp;
518 size_t i, n_res, n_params, n_com, pos;
520 new_in = NEW_ARR_F(ir_node *, 0);
521 for (p = env->cl_list; p; p = p->next) {
523 ctp = get_Call_type(call);
524 lowered_mtp = lower_mtp(env->flags, ctp);
525 set_Call_type(call, lowered_mtp);
527 n_params = get_Call_n_params(call);
530 for (i = 0, n_res = get_method_n_ress(ctp); i < n_res; ++i) {
531 if (is_compound_type(get_method_res_type(ctp, i)))
535 ARR_RESIZE(ir_node *, new_in, n_params + n_com + pos);
536 memset(new_in, 0, sizeof(*new_in) * (n_params + n_com + pos));
537 add_hidden_param(irg, n_com, &new_in[pos], p, env);
539 /* copy all other parameters */
540 for (i = 0; i < n_params; ++i)
541 new_in[pos++] = get_Call_param(call, i);
542 new_in[0] = get_Call_mem(call);
543 new_in[1] = get_Call_ptr(call);
545 set_irn_in(call, n_params + n_com + 2, new_in);
550 * Transform a graph. If it has compound parameter returns,
551 * remove them and use the hidden parameter instead.
552 * If it calls methods with compound parameter returns, add hidden
555 * @param irg the graph to transform
557 static void transform_irg(compound_call_lowering_flags flags, ir_graph *irg)
559 ir_entity *ent = get_irg_entity(irg);
560 ir_type *mtp, *lowered_mtp, *tp, *ft;
561 size_t i, j, k, n_ress = 0, n_ret_com = 0;
563 ir_node **new_in, *ret, *endbl, *bl, *mem, *copy;
567 mtp = get_entity_type(ent);
569 /* calculate the number of compound returns */
570 n_ress = get_method_n_ress(mtp);
571 for (n_ret_com = i = 0; i < n_ress; ++i) {
572 tp = get_method_res_type(mtp, i);
574 if (is_compound_type(tp))
578 fix_parameter_entities(irg, n_ret_com);
581 /* much easier if we have only one return */
582 normalize_one_return(irg);
584 /* This graph has a compound argument. Create a new type */
585 lowered_mtp = lower_mtp(flags, mtp);
586 set_entity_type(ent, lowered_mtp);
588 /* hidden arguments are added first */
589 env.arg_shift = n_ret_com;
591 /* we must only search for calls */
595 obstack_init(&env.obst);
597 env.dummy_map = pmap_create_ex(8);
599 env.lowered_mtp = lowered_mtp;
600 env.only_local_mem = 1;
603 /* scan the code, fix argument numbers and collect calls. */
604 irg_walk_graph(irg, firm_clear_link, fix_args_and_collect_calls, &env);
608 fix_call_list(irg, &env);
615 /* STEP 1: find the return. This is simple, we have normalized the graph. */
616 endbl = get_irg_end_block(irg);
618 for (idx = get_Block_n_cfgpreds(endbl) - 1; idx >= 0; --idx) {
619 ir_node *pred = get_Block_cfgpred(endbl, idx);
621 if (is_Return(pred)) {
627 /* in case of infinite loops, there might be no return */
630 * Now fix the Return node of the current graph.
635 * STEP 2: fix it. For all compound return values add a CopyB,
636 * all others are copied.
638 NEW_ARR_A(ir_node *, new_in, n_ress + 1);
640 bl = get_nodes_block(ret);
641 mem = get_Return_mem(ret);
643 ft = get_irg_frame_type(irg);
644 NEW_ARR_A(cr_pair, cr_opt, n_ret_com);
646 for (j = 1, i = k = 0; i < n_ress; ++i) {
647 ir_node *pred = get_Return_res(ret, i);
648 tp = get_method_res_type(mtp, i);
650 if (is_compound_type(tp)) {
651 ir_node *arg = get_irg_args(irg);
652 arg = new_r_Proj(arg, mode_P_data, k);
655 if (is_Unknown(pred)) {
656 /* The Return(Unknown) is the Firm construct for a
657 * missing return. Do nothing. */
660 * Sorrily detecting that copy-return is possible isn't
661 * that simple. We must check, that the hidden address
662 * is alias free during the whole function.
663 * A simple heuristic: all Loads/Stores inside
664 * the function access only local frame.
666 if (env.only_local_mem && is_compound_address(ft, pred)) {
667 /* we can do the copy-return optimization here */
668 cr_opt[n_cr_opt].ent = get_Sel_entity(pred);
669 cr_opt[n_cr_opt].arg = arg;
671 } else { /* copy-return optimization is impossible, do the copy. */
679 mem = new_r_Proj(copy, mode_M, pn_CopyB_M);
682 if (flags & LF_RETURN_HIDDEN) {
686 } else { /* scalar return value */
691 /* replace the in of the Return */
693 set_irn_in(ret, j, new_in);
699 irg_walk_graph(irg, NULL, do_copy_return_opt, cr_opt);
701 for (c = 0, n = ARR_LEN(cr_opt); c < n; ++c) {
702 free_entity(cr_opt[c].ent);
708 pmap_destroy(env.dummy_map);
709 obstack_free(&env.obst, NULL);
712 static void lower_method_types(type_or_ent tore, void *env)
714 const compound_call_lowering_flags *flags
715 = (const compound_call_lowering_flags*)env;
717 /* fix method entities */
718 if (is_entity(tore.ent)) {
719 ir_entity *ent = tore.ent;
720 ir_type *tp = get_entity_type(ent);
721 ir_type *lowered = lower_mtp(*flags, tp);
722 set_entity_type(ent, lowered);
724 ir_type *tp = tore.typ;
726 /* fix pointer to methods */
727 if (is_Pointer_type(tp)) {
728 ir_type *points_to = get_pointer_points_to_type(tp);
729 ir_type *lowered_points_to = lower_mtp(*flags, points_to);
730 set_pointer_points_to_type(tp, lowered_points_to);
735 void lower_calls_with_compounds(compound_call_lowering_flags flags)
739 pointer_types = pmap_create();
740 lowered_mtps = pmap_create();
742 /* first step: Transform all graphs */
743 for (i = 0, n = get_irp_n_irgs(); i < n; ++i) {
744 ir_graph *irg = get_irp_irg(i);
745 transform_irg(flags, irg);
748 /* second step: Lower all method types of visible entities */
749 type_walk(NULL, lower_method_types, &flags);
751 pmap_destroy(lowered_mtps);
752 pmap_destroy(pointer_types);