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));
150 lowered->attr.ma.has_compound_ret_parameter = true;
153 for (i = 0; i < nn_params; ++i)
154 set_method_param_type(lowered, i, params[i]);
155 for (i = 0; i < nn_ress; ++i)
156 set_method_res_type(lowered, i, results[i]);
158 set_method_variadicity(lowered, get_method_variadicity(mtp));
160 /* associate the lowered type with the original one for easier access */
161 set_method_calling_convention(lowered, get_method_calling_convention(mtp) | cc_compound_ret);
162 set_method_additional_properties(lowered, get_method_additional_properties(mtp));
164 set_lowered_type(mtp, lowered);
165 pmap_insert(lowered_mtps, mtp, lowered);
173 typedef struct cl_entry cl_entry;
175 cl_entry *next; /**< Pointer to the next entry. */
176 ir_node *call; /**< Pointer to the Call node. */
177 ir_node *copyb; /**< List of all CopyB nodes. */
181 * Walker environment for fix_args_and_collect_calls().
183 typedef struct wlk_env_t {
184 size_t arg_shift; /**< The Argument index shift for parameters. */
185 struct obstack obst; /**< An obstack to allocate the data on. */
186 cl_entry *cl_list; /**< The call list. */
187 pmap *dummy_map; /**< A map for finding the dummy arguments. */
188 compound_call_lowering_flags flags;
189 ir_type *lowered_mtp; /**< The lowered method type of the current irg if any. */
190 unsigned only_local_mem:1; /**< Set if only local memory access was found. */
191 unsigned changed:1; /**< Set if the current graph was changed. */
195 * Return the call list entry of a call node.
196 * If no entry exists yet, allocate one and enter the node into
197 * the call list of the environment.
199 * @param call A Call node.
200 * @param env The environment.
202 static cl_entry *get_Call_entry(ir_node *call, wlk_env *env)
204 cl_entry *res = (cl_entry*)get_irn_link(call);
206 res = OALLOC(&env->obst, cl_entry);
207 res->next = env->cl_list;
210 set_irn_link(call, res);
217 * Finds the base address of an address by skipping Sel's and address
220 * @param adr the address
221 * @param pEnt points to the base entity if any
223 static ir_node *find_base_adr(ir_node *ptr, ir_entity **pEnt)
225 ir_entity *ent = NULL;
226 assert(mode_is_reference(get_irn_mode(ptr)));
230 ent = get_Sel_entity(ptr);
231 ptr = get_Sel_ptr(ptr);
233 else if (is_Add(ptr)) {
234 ir_node *left = get_Add_left(ptr);
235 if (mode_is_reference(get_irn_mode(left)))
238 ptr = get_Add_right(ptr);
240 } else if (is_Sub(ptr)) {
241 ptr = get_Sub_left(ptr);
251 * Check if a given pointer represents non-local memory.
253 static void check_ptr(ir_node *ptr, wlk_env *env)
255 ir_storage_class_class_t sc;
258 /* still alias free */
259 ptr = find_base_adr(ptr, &ent);
260 sc = get_base_sc(classify_pointer(ptr, ent));
261 if (sc != ir_sc_localvar && sc != ir_sc_malloced) {
262 /* non-local memory access */
263 env->only_local_mem = 0;
268 * Returns non-zero if a Call is surely a self-recursive Call.
269 * Beware: if this functions returns 0, the call might be self-recursive!
271 static bool is_self_recursive_Call(const ir_node *call)
273 const ir_node *callee = get_Call_ptr(call);
275 if (is_SymConst_addr_ent(callee)) {
276 const ir_entity *ent = get_SymConst_entity(callee);
277 const ir_graph *irg = get_entity_irg(ent);
278 if (irg == get_irn_irg(call))
285 * Post walker: shift all parameter indexes
286 * and collect Calls with compound returns in the call list.
287 * If a non-alias free memory access is found, reset the alias free
290 static void fix_args_and_collect_calls(ir_node *n, void *ctx)
292 wlk_env *env = (wlk_env*)ctx;
296 switch (get_irn_opcode(n)) {
299 if (env->only_local_mem) {
300 ptr = get_irn_n(n, 1);
305 if (env->arg_shift > 0) {
306 ir_node *pred = get_Proj_pred(n);
307 ir_graph *irg = get_irn_irg(n);
309 /* Fix the argument numbers */
310 if (pred == get_irg_args(irg)) {
311 long pnr = get_Proj_proj(n);
312 set_Proj_proj(n, pnr + env->arg_shift);
320 if (! is_self_recursive_Call(n)) {
321 /* any non self recursive call might access global memory */
322 env->only_local_mem = 0;
325 ctp = get_Call_type(n);
326 /* check for compound returns */
327 for (i = 0, n_res = get_method_n_ress(ctp); i < n_res; ++i) {
328 if (is_compound_type(get_method_res_type(ctp, i))) {
330 * This is a call with a compound return. As the result
331 * might be ignored, we must put it in the list.
333 (void)get_Call_entry(n, env);
340 ir_node *src = get_CopyB_src(n);
341 if (env->only_local_mem) {
342 check_ptr(get_CopyB_src(n), env);
343 if (env->only_local_mem)
344 check_ptr(get_CopyB_dst(n), env);
346 /* check for compound returns */
348 ir_node *proj = get_Proj_pred(src);
349 if (is_Proj(proj) && get_Proj_proj(proj) == pn_Call_T_result) {
350 ir_node *call = get_Proj_pred(proj);
352 ctp = get_Call_type(call);
353 if (is_compound_type(get_method_res_type(ctp, get_Proj_proj(src)))) {
354 /* found a CopyB from compound Call result */
355 cl_entry *e = get_Call_entry(call, env);
356 set_irn_link(n, e->copyb);
371 * Returns non-zero if a node is a compound address
372 * of a frame-type entity.
374 * @param ft the frame type
375 * @param adr the node
377 static bool is_compound_address(ir_type *ft, ir_node *adr)
383 if (get_Sel_n_indexs(adr) != 0)
385 ent = get_Sel_entity(adr);
386 return get_entity_owner(ent) == ft;
389 /** A pair for the copy-return-optimization. */
390 typedef struct cr_pair {
391 ir_entity *ent; /**< the entity than can be removed from the frame */
392 ir_node *arg; /**< the argument that replaces the entities address */
396 * Post walker: fixes all entities addresses for the copy-return
399 * Note: We expect the length of the cr_pair array (i.e. number of compound
400 * return values) to be 1 (C, C++) in almost all cases, so ignore the
401 * linear search complexity here.
403 static void do_copy_return_opt(ir_node *n, void *ctx)
406 ir_entity *ent = get_Sel_entity(n);
407 cr_pair *arr = (cr_pair*)ctx;
410 for (i = 0, l = ARR_LEN(arr); i < l; ++i) {
411 if (ent == arr[i].ent) {
412 exchange(n, arr[i].arg);
420 * Return a Sel node that selects a dummy argument of type tp.
421 * Dummy arguments are only needed once and we use a map
423 * We could even assign all dummy arguments the same offset
424 * in the frame type ...
426 * @param irg the graph
427 * @param block the block where a newly create Sel should be placed
428 * @param tp the type of the dummy entity that should be create
429 * @param env the environment
431 static ir_node *get_dummy_sel(ir_graph *irg, ir_node *block, ir_type *tp,
437 /* use a map the check if we already create such an entity */
438 e = pmap_find(env->dummy_map, tp);
440 ent = (ir_entity*)e->value;
442 ir_type *ft = get_irg_frame_type(irg);
443 ident *dummy_id = id_unique("dummy.%u");
444 ent = new_entity(ft, dummy_id, tp);
445 pmap_insert(env->dummy_map, tp, ent);
447 if (get_type_state(ft) == layout_fixed) {
448 /* Fix the layout again */
449 panic("Fixed layout not implemented");
452 return new_r_simpleSel(block, get_irg_no_mem(irg), get_irg_frame(irg), ent);
456 * Add the hidden parameter from the CopyB node to the Call node.
458 * @param irg the graph
459 * @param n_com number of compound results (will be number of hidden parameters)
460 * @param ins in array to store the hidden parameters into
461 * @param entry the call list
462 * @param env the environment
464 static void add_hidden_param(ir_graph *irg, size_t n_com, ir_node **ins,
465 cl_entry *entry, wlk_env *env)
467 ir_node *p, *n, *mem, *blk;
471 for (p = entry->copyb; p; p = n) {
472 ir_node *src = get_CopyB_src(p);
473 size_t idx = get_Proj_proj(src);
474 n = (ir_node*)get_irn_link(p);
476 ins[idx] = get_CopyB_dst(p);
477 mem = get_CopyB_mem(p);
478 blk = get_nodes_block(p);
480 /* get rid of the CopyB */
481 turn_into_tuple(p, pn_CopyB_max+1);
482 set_Tuple_pred(p, pn_CopyB_M, mem);
483 set_Tuple_pred(p, pn_CopyB_X_regular, new_r_Jmp(blk));
484 set_Tuple_pred(p, pn_CopyB_X_except, new_r_Bad(irg, mode_X));
488 /* now create dummy entities for function with ignored return value */
489 if (n_args < n_com) {
490 ir_type *ctp = get_Call_type(entry->call);
494 if (is_lowered_type(ctp))
495 ctp = get_associated_type(ctp);
497 for (j = i = 0; i < get_method_n_ress(ctp); ++i) {
498 ir_type *rtp = get_method_res_type(ctp, i);
499 if (is_compound_type(rtp)) {
501 ins[j] = get_dummy_sel(irg, get_nodes_block(entry->call), rtp, env);
509 * Fix all calls on a call list by adding hidden parameters.
511 * @param irg the graph
512 * @param env the environment
514 static void fix_call_list(ir_graph *irg, wlk_env *env)
517 ir_node *call, **new_in;
518 ir_type *ctp, *lowered_mtp;
519 size_t i, n_res, n_params, n_com, pos;
521 new_in = NEW_ARR_F(ir_node *, 0);
522 for (p = env->cl_list; p; p = p->next) {
524 ctp = get_Call_type(call);
525 lowered_mtp = lower_mtp(env->flags, ctp);
526 set_Call_type(call, lowered_mtp);
528 n_params = get_Call_n_params(call);
531 for (i = 0, n_res = get_method_n_ress(ctp); i < n_res; ++i) {
532 if (is_compound_type(get_method_res_type(ctp, i)))
536 ARR_RESIZE(ir_node *, new_in, n_params + n_com + pos);
537 memset(new_in, 0, sizeof(*new_in) * (n_params + n_com + pos));
538 add_hidden_param(irg, n_com, &new_in[pos], p, env);
540 /* copy all other parameters */
541 for (i = 0; i < n_params; ++i)
542 new_in[pos++] = get_Call_param(call, i);
543 new_in[0] = get_Call_mem(call);
544 new_in[1] = get_Call_ptr(call);
546 set_irn_in(call, n_params + n_com + 2, new_in);
551 * Transform a graph. If it has compound parameter returns,
552 * remove them and use the hidden parameter instead.
553 * If it calls methods with compound parameter returns, add hidden
556 * @param irg the graph to transform
558 static void transform_irg(compound_call_lowering_flags flags, ir_graph *irg)
560 ir_entity *ent = get_irg_entity(irg);
561 ir_type *mtp, *lowered_mtp, *tp, *ft;
562 size_t i, j, k, n_ress = 0, n_ret_com = 0;
564 ir_node **new_in, *ret, *endbl, *bl, *mem, *copy;
568 mtp = get_entity_type(ent);
570 /* calculate the number of compound returns */
571 n_ress = get_method_n_ress(mtp);
572 for (n_ret_com = i = 0; i < n_ress; ++i) {
573 tp = get_method_res_type(mtp, i);
575 if (is_compound_type(tp))
579 fix_parameter_entities(irg, n_ret_com);
582 /* much easier if we have only one return */
583 normalize_one_return(irg);
585 /* This graph has a compound argument. Create a new type */
586 lowered_mtp = lower_mtp(flags, mtp);
587 set_entity_type(ent, lowered_mtp);
589 /* hidden arguments are added first */
590 env.arg_shift = n_ret_com;
592 /* we must only search for calls */
596 obstack_init(&env.obst);
598 env.dummy_map = pmap_create_ex(8);
600 env.lowered_mtp = lowered_mtp;
601 env.only_local_mem = 1;
604 /* scan the code, fix argument numbers and collect calls. */
605 irg_walk_graph(irg, firm_clear_link, fix_args_and_collect_calls, &env);
609 fix_call_list(irg, &env);
616 /* STEP 1: find the return. This is simple, we have normalized the graph. */
617 endbl = get_irg_end_block(irg);
619 for (idx = get_Block_n_cfgpreds(endbl) - 1; idx >= 0; --idx) {
620 ir_node *pred = get_Block_cfgpred(endbl, idx);
622 if (is_Return(pred)) {
628 /* in case of infinite loops, there might be no return */
631 * Now fix the Return node of the current graph.
636 * STEP 2: fix it. For all compound return values add a CopyB,
637 * all others are copied.
639 NEW_ARR_A(ir_node *, new_in, n_ress + 1);
641 bl = get_nodes_block(ret);
642 mem = get_Return_mem(ret);
644 ft = get_irg_frame_type(irg);
645 NEW_ARR_A(cr_pair, cr_opt, n_ret_com);
647 for (j = 1, i = k = 0; i < n_ress; ++i) {
648 ir_node *pred = get_Return_res(ret, i);
649 tp = get_method_res_type(mtp, i);
651 if (is_compound_type(tp)) {
652 ir_node *arg = get_irg_args(irg);
653 arg = new_r_Proj(arg, mode_P_data, k);
656 if (is_Unknown(pred)) {
657 /* The Return(Unknown) is the Firm construct for a
658 * missing return. Do nothing. */
661 * Sorrily detecting that copy-return is possible isn't
662 * that simple. We must check, that the hidden address
663 * is alias free during the whole function.
664 * A simple heuristic: all Loads/Stores inside
665 * the function access only local frame.
667 if (env.only_local_mem && is_compound_address(ft, pred)) {
668 /* we can do the copy-return optimization here */
669 cr_opt[n_cr_opt].ent = get_Sel_entity(pred);
670 cr_opt[n_cr_opt].arg = arg;
672 } else { /* copy-return optimization is impossible, do the copy. */
680 mem = new_r_Proj(copy, mode_M, pn_CopyB_M);
683 if (flags & LF_RETURN_HIDDEN) {
687 } else { /* scalar return value */
692 /* replace the in of the Return */
694 set_irn_in(ret, j, new_in);
700 irg_walk_graph(irg, NULL, do_copy_return_opt, cr_opt);
702 for (c = 0, n = ARR_LEN(cr_opt); c < n; ++c) {
703 free_entity(cr_opt[c].ent);
709 pmap_destroy(env.dummy_map);
710 obstack_free(&env.obst, NULL);
713 static void lower_method_types(type_or_ent tore, void *env)
715 const compound_call_lowering_flags *flags
716 = (const compound_call_lowering_flags*)env;
718 /* fix method entities */
719 if (is_entity(tore.ent)) {
720 ir_entity *ent = tore.ent;
721 ir_type *tp = get_entity_type(ent);
722 ir_type *lowered = lower_mtp(*flags, tp);
723 set_entity_type(ent, lowered);
725 ir_type *tp = tore.typ;
727 /* fix pointer to methods */
728 if (is_Pointer_type(tp)) {
729 ir_type *points_to = get_pointer_points_to_type(tp);
730 ir_type *lowered_points_to = lower_mtp(*flags, points_to);
731 set_pointer_points_to_type(tp, lowered_points_to);
736 void lower_calls_with_compounds(compound_call_lowering_flags flags)
740 pointer_types = pmap_create();
741 lowered_mtps = pmap_create();
743 /* first step: Transform all graphs */
744 for (i = 0, n = get_irp_n_irgs(); i < n; ++i) {
745 ir_graph *irg = get_irp_irg(i);
746 transform_irg(flags, irg);
749 /* second step: Lower all method types of visible entities */
750 type_walk(NULL, lower_method_types, &flags);
752 pmap_destroy(lowered_mtps);
753 pmap_destroy(pointer_types);