2 * Copyright (C) 1995-2008 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
39 #include "iroptimize.h"
44 /** A type map for def_find_pointer_type. */
45 static pmap *type_map;
48 * Default implementation for finding a pointer type for a given element type.
49 * Simple create a new one.
51 static ir_type *def_find_pointer_type(ir_type *e_type, int alignment)
56 /* Mode and alignment are always identical in all calls to def_find_pointer_type(), so
57 we simply can use a map from the element type to the pointer type. */
58 e = pmap_find(type_map, e_type);
62 res = new_type_pointer(e_type);
63 set_type_alignment_bytes(res, alignment);
64 pmap_insert(type_map, e_type, res);
70 * Creates a new lowered type for a method type with compound
71 * arguments. The new type is associated to the old one and returned.
73 * @param lp parameter struct
74 * @param mtp the method type to lower
76 * The current implementation expects that a lowered type already
77 * includes the necessary changes ...
79 static ir_type *create_modified_mtd_type(const lower_params_t *lp, ir_type *mtp)
81 ir_type *lowered, *ptr_tp, *value_type;
82 ir_type **params, **results, *res_tp;
84 ir_mode *modes[MAX_REGISTER_RET_VAL];
85 int n_ress, n_params, nn_ress, nn_params, i, first_variadic;
86 add_hidden hidden_params;
90 if (is_lowered_type(mtp)) {
91 /* the type is already lowered. Not handled yet. */
92 assert(0 && "lowered types NYI");
95 lowered = get_associated_type(mtp);
99 n_ress = get_method_n_ress(mtp);
100 NEW_ARR_A(ir_type *, results, n_ress);
102 n_params = get_method_n_params(mtp);
103 NEW_ARR_A(ir_type *, params, n_params + n_ress);
105 NEW_ARR_A(int, param_map, n_params + n_ress);
107 first_variadic = get_method_first_variadic_param_index(mtp);
109 hidden_params = lp->hidden_params;
110 if (hidden_params == ADD_HIDDEN_SMART &&
111 get_method_variadicity(mtp) == variadicity_variadic)
112 hidden_params = ADD_HIDDEN_ALWAYS_IN_FRONT;
114 if (hidden_params == ADD_HIDDEN_ALWAYS_IN_FRONT) {
115 /* add hidden in front */
116 for (nn_ress = nn_params = i = 0; i < n_ress; ++i) {
117 res_tp = get_method_res_type(mtp, i);
119 if (is_compound_type(res_tp)) {
122 if (lp->flags & LF_SMALL_CMP_IN_REGS)
123 n_regs = lp->ret_compound_in_regs(res_tp, modes);
126 /* this compound will be returned solely in registers */
127 panic("Returning compounds in registers not yet implemented");
130 /* this compound will be allocated on callers stack and its
131 address will be transmitted as a hidden parameter. */
132 ptr_tp = lp->find_pointer_type(res_tp, lp->def_ptr_alignment);
133 params[nn_params] = ptr_tp;
134 param_map[nn_params] = -1 - i;
137 if (lp->flags & LF_RETURN_HIDDEN)
138 results[nn_ress++] = ptr_tp;
142 results[nn_ress++] = res_tp;
146 /* move the index of the first variadic parameter */
147 first_variadic += nn_params;
149 for (i = 0; i < n_params; ++i, ++nn_params) {
150 params[nn_params] = get_method_param_type(mtp, i);
151 param_map[nn_params] = i;
154 /* add hidden parameters last */
155 assert(get_method_variadicity(mtp) == variadicity_non_variadic &&
156 "Cannot add hidden parameters at end of variadic function");
158 for (nn_params = 0; nn_params < n_params; ++nn_params) {
159 params[nn_params] = get_method_param_type(mtp, nn_params);
160 param_map[nn_params] = nn_params;
163 for (nn_ress = i = 0; i < n_ress; ++i) {
164 res_tp = get_method_res_type(mtp, i);
166 if (is_compound_type(res_tp)) {
167 params[nn_params] = lp->find_pointer_type(res_tp, lp->def_ptr_alignment);
168 param_map[nn_params] = -1 - i;
171 results[nn_ress++] = res_tp;
176 /* create the new type */
177 lowered = new_d_type_method(nn_params, nn_ress, get_type_dbg_info(mtp));
180 for (i = 0; i < nn_params; ++i)
181 set_method_param_type(lowered, i, params[i]);
182 for (i = 0; i < nn_ress; ++i)
183 set_method_res_type(lowered, i, results[i]);
185 var = get_method_variadicity(mtp);
186 set_method_variadicity(lowered, var);
187 if (var == variadicity_variadic)
188 set_method_first_variadic_param_index(lowered, first_variadic);
190 /* associate the lowered type with the original one for easier access */
192 set_method_calling_convention(lowered, get_method_calling_convention(mtp) | cc_compound_ret);
195 set_lowered_type(mtp, lowered);
197 value_type = get_method_value_param_type(mtp);
198 if (value_type != NULL) {
199 /* set new param positions */
200 for (i = 0; i < nn_params; ++i) {
201 ir_entity *ent = get_method_value_param_ent(lowered, i);
202 int pos = param_map[i];
205 set_entity_link(ent, INT_TO_PTR(pos));
207 /* formally return value, ignore for now */
211 id = get_method_param_ident(mtp, pos);
213 set_method_param_ident(lowered, i, id);
214 set_entity_ident(ent, id);
218 set_lowered_type(value_type, get_method_value_param_type(lowered));
227 typedef struct cl_entry cl_entry;
229 cl_entry *next; /**< Pointer to the next entry. */
230 ir_node *call; /**< Pointer to the Call node. */
231 ir_node *copyb; /**< List of all CopyB nodes. */
235 * Walker environment for fix_args_and_collect_calls().
237 typedef struct _wlk_env_t {
238 int arg_shift; /**< The Argument index shift for parameters. */
239 int first_hidden; /**< The index of the first hidden argument. */
240 struct obstack obst; /**< An obstack to allocate the data on. */
241 cl_entry *cl_list; /**< The call list. */
242 pmap *dummy_map; /**< A map for finding the dummy arguments. */
243 unsigned dnr; /**< The dummy index number. */
244 const lower_params_t *params; /**< Lowering parameters. */
245 ir_type *lowered_mtp; /**< The lowered method type of the current irg if any. */
246 ir_type *value_params; /**< The value params type if any. */
247 unsigned only_local_mem:1; /**< Set if only local memory access was found. */
248 unsigned changed:1; /**< Set if the current graph was changed. */
252 * Return the call list entry of a call node.
253 * If no entry exists yet, allocate one and enter the node into
254 * the call list of the environment.
256 * @param call A Call node.
257 * @param env The environment.
259 static cl_entry *get_Call_entry(ir_node *call, wlk_env *env) {
260 cl_entry *res = get_irn_link(call);
262 cl_entry *res = OALLOC(&env->obst, cl_entry);
263 res->next = env->cl_list;
266 set_irn_link(call, res);
273 * Finds the base address of an address by skipping Sel's and address
276 * @param adr the address
277 * @param pEnt points to the base entity if any
279 static ir_node *find_base_adr(ir_node *ptr, ir_entity **pEnt) {
280 ir_entity *ent = NULL;
281 assert(mode_is_reference(get_irn_mode(ptr)));
285 ent = get_Sel_entity(ptr);
286 ptr = get_Sel_ptr(ptr);
288 else if (is_Add(ptr)) {
289 ir_node *left = get_Add_left(ptr);
290 if (mode_is_reference(get_irn_mode(left)))
293 ptr = get_Add_right(ptr);
295 } else if (is_Sub(ptr)) {
296 ptr = get_Sub_left(ptr);
306 * Check if a given pointer represents non-local memory.
308 static void check_ptr(ir_node *ptr, wlk_env *env) {
309 ir_storage_class_class_t sc;
312 /* still alias free */
313 ptr = find_base_adr(ptr, &ent);
314 sc = GET_BASE_SC(classify_pointer(current_ir_graph, ptr, ent));
315 if (sc != ir_sc_localvar && sc != ir_sc_malloced) {
316 /* non-local memory access */
317 env->only_local_mem = 0;
322 * Post walker: shift all parameter indexes
323 * and collect Calls with compound returns in the call list.
324 * If a non-alias free memory access is found, reset the alias free
327 static void fix_args_and_collect_calls(ir_node *n, void *ctx) {
333 switch (get_irn_opcode(n)) {
335 if (env->lowered_mtp != NULL && env->value_params != NULL) {
336 ir_entity *ent = get_Sel_entity(n);
338 if (get_entity_owner(ent) == env->value_params) {
339 int pos = get_struct_member_index(env->value_params, ent) + env->arg_shift;
342 new_ent = get_method_value_param_ent(env->lowered_mtp, pos);
343 set_entity_ident(new_ent, get_entity_ident(ent));
344 set_Sel_entity(n, new_ent);
350 if (env->only_local_mem) {
351 ptr = get_irn_n(n, 1);
356 if (env->arg_shift > 0) {
357 ir_node *pred = get_Proj_pred(n);
359 /* Fix the argument numbers */
360 if (pred == get_irg_args(current_ir_graph)) {
361 long pnr = get_Proj_proj(n);
362 set_Proj_proj(n, pnr + env->arg_shift);
368 if (! is_self_recursive_Call(n)) {
369 /* any non self recursive call might access global memory */
370 env->only_local_mem = 0;
373 ctp = get_Call_type(n);
374 if (env->params->flags & LF_COMPOUND_RETURN) {
375 /* check for compound returns */
376 for (i = get_method_n_ress(ctp) -1; i >= 0; --i) {
377 if (is_compound_type(get_method_res_type(ctp, i))) {
379 * This is a call with a compound return. As the result
380 * might be ignored, we must put it in the list.
382 (void)get_Call_entry(n, env);
389 if (env->only_local_mem) {
390 check_ptr(get_CopyB_src(n), env);
391 if (env->only_local_mem)
392 check_ptr(get_CopyB_dst(n), env);
394 if (env->params->flags & LF_COMPOUND_RETURN) {
395 /* check for compound returns */
396 ir_node *src = get_CopyB_src(n);
397 /* older scheme using value_res_ent */
399 ir_node *proj = get_Sel_ptr(src);
400 if (is_Proj(proj) && get_Proj_proj(proj) == pn_Call_P_value_res_base) {
401 ir_node *call = get_Proj_pred(proj);
403 /* found a CopyB from compound Call result */
404 cl_entry *e = get_Call_entry(call, env);
405 set_irn_link(n, e->copyb);
410 /* new scheme: compound results are determined by the call type only */
412 ir_node *proj = get_Proj_pred(src);
413 if (is_Proj(proj) && get_Proj_proj(proj) == pn_Call_T_result) {
414 ir_node *call = get_Proj_pred(proj);
416 ctp = get_Call_type(call);
417 if (is_compound_type(get_method_res_type(ctp, get_Proj_proj(src)))) {
418 /* found a CopyB from compound Call result */
419 cl_entry *e = get_Call_entry(call, env);
420 set_irn_link(n, e->copyb);
436 * Returns non-zero if a node is a compound address
437 * of a frame-type entity.
439 * @param ft the frame type
440 * @param adr the node
442 static int is_compound_address(ir_type *ft, ir_node *adr)
448 if (get_Sel_n_indexs(adr) != 0)
450 ent = get_Sel_entity(adr);
451 return get_entity_owner(ent) == ft;
454 /** A pair for the copy-return-optimization. */
455 typedef struct cr_pair {
456 ir_entity *ent; /**< the entity than can be removed from the frame */
457 ir_node *arg; /**< the argument that replaces the entities address */
461 * Post walker: fixes all entities addresses for the copy-return
464 * Note: We expect the length of the cr_pair array (ie number of compound
465 * return values) to be 1 (C, C++) in almost all cases, so ignore the
466 * linear search complexity here.
468 static void do_copy_return_opt(ir_node *n, void *ctx) {
473 ir_entity *ent = get_Sel_entity(n);
475 for (i = ARR_LEN(arr) - 1; i >= 0; --i) {
476 if (ent == arr[i].ent) {
477 exchange(n, arr[i].arg);
485 * Return a Sel node that selects a dummy argument of type tp.
486 * Dummy arguments are only needed once and we use a map
488 * We could even assign all dummy arguments the same offset
489 * in the frame type ...
491 * @param irg the graph
492 * @param block the block where a newly create Sel should be placed
493 * @param tp the type of the dummy entity that should be create
494 * @param env the environment
496 static ir_node *get_dummy_sel(ir_graph *irg, ir_node *block, ir_type *tp, wlk_env *env)
501 /* use a map the check if we already create such an entity */
502 e = pmap_find(env->dummy_map, tp);
506 ir_type *ft = get_irg_frame_type(irg);
509 snprintf(buf, sizeof(buf), "dummy.%u", env->dnr++);
510 ent = new_entity(ft, new_id_from_str(buf), tp);
511 pmap_insert(env->dummy_map, tp, ent);
513 if (get_type_state(ft) == layout_fixed) {
514 /* Fix the layout again */
515 assert(0 && "Fixed layout not implemented");
518 return new_r_simpleSel(
526 * Add the hidden parameter from the CopyB node to the Call node.
528 * @param irg the graph
529 * @param n_com number of compound results (will be number of hidden parameters)
530 * @param ins in array to store the hidden parameters into
531 * @param entry the call list
532 * @param env the environment
534 static void add_hidden_param(ir_graph *irg, int n_com, ir_node **ins, cl_entry *entry, wlk_env *env)
536 ir_node *p, *n, *src, *mem, *blk;
542 for (p = entry->copyb; p; p = n) {
544 src = get_CopyB_src(p);
546 /* old scheme using value_res_ent */
548 ent = get_Sel_entity(src);
549 owner = get_entity_owner(ent);
551 /* find the hidden parameter index */
552 for (idx = 0; idx < get_struct_n_members(owner); ++idx)
553 if (get_struct_member(owner, idx) == ent)
555 assert(idx < get_struct_n_members(owner));
557 /* new scheme: compound returns are determined by the call type and are Proj's */
558 idx = get_Proj_proj(src);
561 ins[idx] = get_CopyB_dst(p);
562 mem = get_CopyB_mem(p);
563 blk = get_nodes_block(p);
565 /* get rid of the CopyB */
566 turn_into_tuple(p, pn_CopyB_max);
567 set_Tuple_pred(p, pn_CopyB_M, mem);
568 set_Tuple_pred(p, pn_CopyB_X_regular, new_r_Jmp(blk));
569 set_Tuple_pred(p, pn_CopyB_X_except, get_irg_bad(irg));
573 /* now create dummy entities for function with ignored return value */
574 if (n_args < n_com) {
575 ir_type *ctp = get_Call_type(entry->call);
578 if (is_lowered_type(ctp))
579 ctp = get_associated_type(ctp);
581 for (j = i = 0; i < get_method_n_ress(ctp); ++i) {
582 ir_type *rtp = get_method_res_type(ctp, i);
583 if (is_compound_type(rtp)) {
585 ins[j] = get_dummy_sel(irg, get_nodes_block(entry->call), rtp, env);
593 * Fix all calls on a call list by adding hidden parameters.
595 * @param irg the graph
596 * @param env the environment
598 static void fix_call_list(ir_graph *irg, wlk_env *env) {
599 const lower_params_t *lp = env->params;
601 ir_node *call, **new_in;
602 ir_type *ctp, *lowered_mtp;
603 add_hidden hidden_params;
604 int i, n_params, n_com, pos;
606 new_in = NEW_ARR_F(ir_node *, 0);
607 for (p = env->cl_list; p; p = p->next) {
609 ctp = get_Call_type(call);
610 lowered_mtp = create_modified_mtd_type(lp, ctp);
611 set_Call_type(call, lowered_mtp);
613 hidden_params = lp->hidden_params;
614 if (hidden_params == ADD_HIDDEN_SMART &&
615 get_method_variadicity(ctp) == variadicity_variadic)
616 hidden_params = ADD_HIDDEN_ALWAYS_IN_FRONT;
618 n_params = get_Call_n_params(call);
621 for (i = get_method_n_ress(ctp) - 1; i >= 0; --i) {
622 if (is_compound_type(get_method_res_type(ctp, i)))
626 ARR_RESIZE(ir_node *, new_in, n_params + n_com + pos);
627 memset(new_in, 0, sizeof(*new_in) * (n_params + n_com + pos));
628 if (hidden_params == ADD_HIDDEN_ALWAYS_IN_FRONT) {
629 add_hidden_param(irg, n_com, &new_in[pos], p, env);
632 /* copy all other parameters */
633 for (i = 0; i < n_params; ++i)
634 new_in[pos++] = get_Call_param(call, i);
635 if (hidden_params == ADD_HIDDEN_ALWAYS_LAST) {
636 add_hidden_param(irg, n_com, &new_in[pos], p, env);
639 new_in[0] = get_Call_mem(call);
640 new_in[1] = get_Call_ptr(call);
642 set_irn_in(call, n_params + n_com + 2, new_in);
647 * Transform a graph. If it has compound parameter returns,
648 * remove them and use the hidden parameter instead.
649 * If it calls methods with compound parameter returns, add hidden
652 * @param lp parameter struct
653 * @param irg the graph to transform
655 static void transform_irg(const lower_params_t *lp, ir_graph *irg)
657 ir_graph * rem = current_ir_graph;
658 ir_entity *ent = get_irg_entity(irg);
659 ir_type *mtp, *lowered_mtp, *tp, *ft;
660 int i, j, k, n_ress = 0, n_ret_com = 0, n_cr_opt;
661 ir_node **new_in, *ret, *endbl, *bl, *mem, *copy;
664 add_hidden hidden_params;
666 current_ir_graph = irg;
668 assert(ent && "Cannot transform graph without an entity");
669 assert(get_irg_phase_state(irg) == phase_high && "call lowering must be done in phase high");
671 mtp = get_entity_type(ent);
673 if (lp->flags & LF_COMPOUND_RETURN) {
674 /* calculate the number of compound returns */
675 n_ress = get_method_n_ress(mtp);
676 for (n_ret_com = i = 0; i < n_ress; ++i) {
677 tp = get_method_res_type(mtp, i);
679 if (is_compound_type(tp))
685 /* much easier if we have only one return */
686 normalize_one_return(irg);
688 /* This graph has a compound argument. Create a new type */
689 lowered_mtp = create_modified_mtd_type(lp, mtp);
690 set_entity_type(ent, lowered_mtp);
692 hidden_params = lp->hidden_params;
693 if (hidden_params == ADD_HIDDEN_SMART &&
694 get_method_variadicity(mtp) == variadicity_variadic)
695 hidden_params = ADD_HIDDEN_ALWAYS_IN_FRONT;
697 if (hidden_params == ADD_HIDDEN_ALWAYS_IN_FRONT) {
698 /* hidden arguments are added first */
699 env.arg_shift = n_ret_com;
700 env.first_hidden = 0;
702 /* hidden arguments are added last */
704 env.first_hidden = get_method_n_params(mtp);
707 /* we must only search for calls */
711 obstack_init(&env.obst);
713 env.dummy_map = pmap_create_ex(8);
716 env.lowered_mtp = lowered_mtp;
717 env.value_params = get_method_value_param_type(mtp);
718 env.only_local_mem = 1;
721 /* scan the code, fix argument numbers and collect calls. */
722 irg_walk_graph(irg, firm_clear_link, fix_args_and_collect_calls, &env);
726 fix_call_list(irg, &env);
732 * Now fix the Return node of the current graph.
736 /* STEP 1: find the return. This is simple, we have normalized the graph. */
737 endbl = get_irg_end_block(irg);
739 for (i = get_Block_n_cfgpreds(endbl) - 1; i >= 0; --i) {
740 ir_node *pred = get_Block_cfgpred(endbl, i);
742 if (is_Return(pred)) {
747 /* there should always be a return */
751 * STEP 2: fix it. For all compound return values add a CopyB,
752 * all others are copied.
754 NEW_ARR_A(ir_node *, new_in, n_ress + 1);
756 bl = get_nodes_block(ret);
757 mem = get_Return_mem(ret);
759 ft = get_irg_frame_type(irg);
760 NEW_ARR_A(cr_pair, cr_opt, n_ret_com);
762 for (j = 1, i = k = 0; i < n_ress; ++i) {
763 ir_node *pred = get_Return_res(ret, i);
764 tp = get_method_res_type(mtp, i);
766 if (is_compound_type(tp)) {
767 ir_node *arg = get_irg_args(irg);
768 arg = new_r_Proj(get_nodes_block(arg), arg, mode_P_data, env.first_hidden + k);
771 if (is_Unknown(pred)) {
772 /* The Return(Unknown) is the Firm construct for a missing return.
776 * Sorrily detecting that copy-return is possible isn't that simple.
777 * We must check, that the hidden address is alias free during the whole
779 * A simple heuristic: all Loads/Stores inside
780 * the function access only local frame.
782 if (env.only_local_mem && is_compound_address(ft, pred)) {
783 /* we can do the copy-return optimization here */
784 cr_opt[n_cr_opt].ent = get_Sel_entity(pred);
785 cr_opt[n_cr_opt].arg = arg;
787 } else { /* copy-return optimization is impossible, do the copy. */
795 mem = new_r_Proj(bl, copy, mode_M, pn_CopyB_M);
798 if (lp->flags & LF_RETURN_HIDDEN) {
802 } else { /* scalar return value */
807 /* replace the in of the Return */
809 set_irn_in(ret, j, new_in);
812 irg_walk_graph(irg, NULL, do_copy_return_opt, cr_opt);
814 for (i = ARR_LEN(cr_opt) - 1; i >= 0; --i) {
815 remove_class_member(ft, cr_opt[i].ent);
818 } /* if (n_ret_com) */
820 pmap_destroy(env.dummy_map);
821 obstack_free(&env.obst, NULL);
824 /* invalidate the analysis info */
825 set_irg_outs_inconsistent(irg);
826 set_irg_loopinfo_state(irg, loopinfo_inconsistent);
828 current_ir_graph = rem;
832 * Returns non-zero if the given type is a method
833 * type that must be lowered.
835 * @param lp lowering parameters
836 * @param tp The type.
838 static int must_be_lowered(const lower_params_t *lp, ir_type *tp) {
842 if (is_Method_type(tp)) {
843 if (lp->flags & LF_COMPOUND_RETURN) {
844 /* check for compound returns */
845 n_ress = get_method_n_ress(tp);
846 for (i = 0; i < n_ress; ++i) {
847 res_tp = get_method_res_type(tp, i);
849 if (is_compound_type(res_tp))
858 * type-walker: lower all method types of entities
859 * and points-to types.
861 static void lower_method_types(type_or_ent tore, void *env)
863 const lower_params_t *lp = env;
866 /* fix method entities */
867 if (is_entity(tore.ent)) {
868 ir_entity *ent = tore.ent;
869 tp = get_entity_type(ent);
871 if (must_be_lowered(lp, tp)) {
872 tp = create_modified_mtd_type(lp, tp);
873 set_entity_type(ent, tp);
878 /* fix pointer to methods */
879 if (is_Pointer_type(tp)) {
880 ir_type *etp = get_pointer_points_to_type(tp);
881 if (must_be_lowered(lp, etp)) {
882 etp = create_modified_mtd_type(lp, etp);
883 set_pointer_points_to_type(tp, etp);
890 * Lower calls with compound parameters and return types.
891 * This function does the following transformations:
893 * - Adds a new (hidden) pointer parameter for
894 * any return compound type.
896 * - Use of the hidden parameters in the function code.
898 * - Change all calls to functions with compound return
899 * by providing space for the hidden parameter on the callers
902 * - Replace a possible block copy after the function call.
904 void lower_calls_with_compounds(const lower_params_t *params)
908 lower_params_t param = *params;
910 if (param.find_pointer_type == NULL) {
911 param.find_pointer_type = def_find_pointer_type;
912 type_map = pmap_create_ex(8);
916 /* first step: Transform all graphs */
917 for (i = get_irp_n_irgs() - 1; i >= 0; --i) {
918 irg = get_irp_irg(i);
920 transform_irg(¶m, irg);
923 /* second step: Lower all method types of visible entities */
924 type_walk(NULL, lower_method_types, ¶m);
927 pmap_destroy(type_map);