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4 * This file is part of libFirm.
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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 "lower_calls.h"
46 /** A type map for def_find_pointer_type. */
47 static pmap *type_map;
50 * Default implementation for finding a pointer type for a given element type.
51 * Simple create a new one.
53 static ir_type *def_find_pointer_type(ir_type *e_type, ir_mode *mode, int alignment)
58 /* Mode and alignment are always identical in all calls to def_find_pointer_type(), so
59 we simply can use a map from the element type to the pointer type. */
60 e = pmap_find(type_map, e_type);
64 res = new_type_pointer(mangle_u(get_type_ident(e_type), new_id_from_chars("Ptr", 3)), e_type, mode);
65 set_type_alignment_bytes(res, alignment);
66 pmap_insert(type_map, e_type, res);
72 * Creates a new lowered type for a method type with compound
73 * arguments. The new type is associated to the old one and returned.
75 * @param lp parameter struct
76 * @param mtp the method type to lower
78 * The current implementation expects that a lowered type already
79 * includes the necessary changes ...
81 static ir_type *create_modified_mtd_type(const lower_params_t *lp, ir_type *mtp)
83 ir_type *lowered, *ptr_tp;
84 ir_type **params, **results, *res_tp;
85 ir_mode *modes[MAX_REGISTER_RET_VAL];
86 int n_ress, n_params, nn_ress, nn_params, i, first_variadic;
88 add_hidden hidden_params;
91 if (is_lowered_type(mtp)) {
92 /* the type is already lowered. Not handled yet. */
93 assert(0 && "lowered types NYI");
96 lowered = get_associated_type(mtp);
100 n_ress = get_method_n_ress(mtp);
101 NEW_ARR_A(ir_type *, results, n_ress);
103 n_params = get_method_n_params(mtp);
104 NEW_ARR_A(ir_type *, params, n_params + n_ress);
106 first_variadic = get_method_first_variadic_param_index(mtp);
108 hidden_params = lp->hidden_params;
109 if (hidden_params == ADD_HIDDEN_SMART &&
110 get_method_variadicity(mtp) == variadicity_variadic)
111 hidden_params = ADD_HIDDEN_ALWAYS_IN_FRONT;
113 if (hidden_params == ADD_HIDDEN_ALWAYS_IN_FRONT) {
114 /* add hidden in front */
115 for (nn_ress = nn_params = i = 0; i < n_ress; ++i) {
116 res_tp = get_method_res_type(mtp, i);
118 if (is_compound_type(res_tp)) {
121 if (lp->flags & LF_SMALL_CMP_IN_REGS)
122 n_regs = lp->ret_compound_in_regs(res_tp, modes);
125 /* this compound will be returned solely in registers */
129 /* this compound will be allocated on callers stack and its
130 address will be transmitted as a hidden parameter. */
131 ptr_tp = lp->find_pointer_type(res_tp, get_modeP_data(), lp->def_ptr_alignment);
132 params[nn_params++] = ptr_tp;
133 if (lp->flags & LF_RETURN_HIDDEN)
134 results[nn_ress++] = ptr_tp;
138 results[nn_ress++] = res_tp;
141 /* move the index of the first variadic parameter */
142 first_variadic += nn_params;
144 for (i = 0; i < n_params; ++i)
145 params[nn_params++] = get_method_param_type(mtp, i);
148 /* add hidden parameters last */
149 assert(get_method_variadicity(mtp) == variadicity_non_variadic &&
150 "Cannot add hidden parameters at end of variadic function");
152 for (nn_params = 0; nn_params < n_params; ++nn_params)
153 params[nn_params] = get_method_param_type(mtp, nn_params);
155 for (nn_ress = i = 0; i < n_ress; ++i) {
156 res_tp = get_method_res_type(mtp, i);
158 if (is_compound_type(res_tp))
159 params[nn_params++] = lp->find_pointer_type(res_tp, get_modeP_data(), lp->def_ptr_alignment);
161 results[nn_ress++] = res_tp;
165 /* create the new type */
166 id = mangle_u(new_id_from_chars("L", 1), get_type_ident(mtp));
167 lowered = new_d_type_method(id, nn_params, nn_ress, get_type_dbg_info(mtp));
170 for (i = 0; i < nn_params; ++i)
171 set_method_param_type(lowered, i, params[i]);
172 for (i = 0; i < nn_ress; ++i)
173 set_method_res_type(lowered, i, results[i]);
175 var = get_method_variadicity(mtp);
176 set_method_variadicity(lowered, var);
177 if (var == variadicity_variadic)
178 set_method_first_variadic_param_index(lowered, first_variadic);
180 /* associate the lowered type with the original one for easier access */
181 set_lowered_type(mtp, lowered);
189 typedef struct cl_entry cl_entry;
191 cl_entry *next; /**< Pointer to the next entry. */
192 ir_node *call; /**< Pointer to the Call node. */
193 ir_node *copyb; /**< List of all CopyB nodes. */
197 * Walker environment for fix_args_and_collect_calls().
199 typedef struct _wlk_env_t {
200 int arg_shift; /**< The Argument index shift for parameters. */
201 int first_hidden; /**< The index of the first hidden argument. */
202 struct obstack obst; /**< An obstack to allocate the data on. */
203 cl_entry *cl_list; /**< The call list. */
204 pmap *dummy_map; /**< A map for finding the dummy arguments. */
205 unsigned dnr; /**< The dummy index number. */
206 const lower_params_t *params; /**< lowering parameters */
210 * Return the call list entry of a call node.
211 * If no entry exists yet, allocate one and enter the node into
212 * the call list of the environment.
214 * @param call A Call node.
215 * @param env The environment.
217 static cl_entry *get_Call_entry(ir_node *call, wlk_env *env) {
218 cl_entry *res = get_irn_link(call);
220 cl_entry *res = obstack_alloc(&env->obst, sizeof(*res));
221 res->next = env->cl_list;
224 set_irn_link(call, res);
231 * Post walker: shift all parameter indeces
232 * and collect Calls with compound returns in the call list.
234 static void fix_args_and_collect_calls(ir_node *n, void *ctx) {
238 ir_op *op = get_irn_op(n);
240 if (env->arg_shift > 0 && op == op_Proj) {
241 ir_node *pred = get_Proj_pred(n);
243 /* Fix the argument numbers */
244 if (pred == get_irg_args(current_ir_graph)) {
245 long pnr = get_Proj_proj(n);
246 set_Proj_proj(n, pnr + env->arg_shift);
249 else if (op == op_Call) {
250 ctp = get_Call_type(n);
251 if (env->params->flags & LF_COMPOUND_RETURN) {
252 /* check for compound returns */
253 for (i = get_method_n_ress(ctp) -1; i >= 0; --i) {
254 if (is_compound_type(get_method_res_type(ctp, i))) {
256 * This is a call with a compound return. As the result
257 * might be ignored, we must put it in the list.
259 (void)get_Call_entry(n, env);
265 else if (op == op_CopyB && env->params->flags & LF_COMPOUND_RETURN) {
266 /* check for compound returns */
267 ir_node *src = get_CopyB_src(n);
268 /* older scheme using value_res_ent */
270 ir_node *proj = get_Sel_ptr(src);
271 if (is_Proj(proj) && get_Proj_proj(proj) == pn_Call_P_value_res_base) {
272 ir_node *call = get_Proj_pred(proj);
274 /* found a CopyB from compound Call result */
275 cl_entry *e = get_Call_entry(call, env);
276 set_irn_link(n, e->copyb);
281 /* new scheme: compound results are determined by the call type only */
283 ir_node *proj = get_Proj_pred(src);
284 if (is_Proj(proj) && get_Proj_proj(proj) == pn_Call_T_result) {
285 ir_node *call = get_Proj_pred(proj);
287 ctp = get_Call_type(call);
288 if (is_compound_type(get_method_res_type(ctp, get_Proj_proj(src)))) {
289 /* found a CopyB from compound Call result */
290 cl_entry *e = get_Call_entry(call, env);
291 set_irn_link(n, e->copyb);
301 * Returns non-zero if a node is a compound address
302 * of a frame-type entity.
304 * @param ft the frame type
305 * @param adr the node
307 static int is_compound_address(ir_type *ft, ir_node *adr)
313 if (get_Sel_n_indexs(adr) != 0)
315 ent = get_Sel_entity(adr);
316 return get_entity_owner(ent) == ft;
319 /** A pair for the copy-return-optimization. */
320 typedef struct cr_pair {
321 ir_entity *ent; /**< the entity than can be removed from the frame */
322 ir_node *arg; /**< the argument that replaces the entities address */
326 * Post walker: fixes all entities addresses for the copy-return
329 * Note: We expect the length of the cr_pair array (ie number of compound
330 * return values) to be 1 (C, C++) in almost all cases, so ignore the
331 * linear search complexity here.
333 static void do_copy_return_opt(ir_node *n, void *ctx) {
338 ir_entity *ent = get_Sel_entity(n);
340 for (i = ARR_LEN(arr) - 1; i >= 0; --i) {
341 if (ent == arr[i].ent) {
342 exchange(n, arr[i].arg);
350 * Return a Sel node that selects a dummy argument of type tp.
351 * Dummy arguments are only needed once and we use a map
353 * We could even assign all dummy arguments the same offset
354 * in the frame type ...
356 * @param irg the graph
357 * @param block the block where a newly create Sel should be placed
358 * @param tp the type of the dummy entity that should be create
359 * @param env the environment
361 static ir_node *get_dummy_sel(ir_graph *irg, ir_node *block, ir_type *tp, wlk_env *env)
366 /* use a map the check if we already create such an entity */
367 e = pmap_find(env->dummy_map, tp);
371 ir_type *ft = get_irg_frame_type(irg);
374 snprintf(buf, sizeof(buf), "dummy.%u", env->dnr++);
375 ent = new_entity(ft, new_id_from_str(buf), tp);
376 pmap_insert(env->dummy_map, tp, ent);
378 if (get_type_state(ft) == layout_fixed) {
379 /* Fix the layout again */
380 assert(0 && "Fixed layout not implemented");
383 return new_r_simpleSel(
392 * Add the hidden parameter from the CopyB node to the Call node.
394 * @param irg the graph
395 * @param n_com number of compound results (will be number of hidden parameters)
396 * @param ins in array to store the hidden parameters into
397 * @param entry the call list
398 * @param env the environment
400 static void add_hidden_param(ir_graph *irg, int n_com, ir_node **ins, cl_entry *entry, wlk_env *env)
402 ir_node *p, *n, *src, *mem;
408 for (p = entry->copyb; p; p = n) {
410 src = get_CopyB_src(p);
412 /* old scheme using value_res_ent */
414 ent = get_Sel_entity(src);
415 owner = get_entity_owner(ent);
417 /* find the hidden parameter index */
418 for (idx = 0; idx < get_struct_n_members(owner); ++idx)
419 if (get_struct_member(owner, idx) == ent)
421 assert(idx < get_struct_n_members(owner));
425 /* new scheme: compound returns are determined by the call type and are Proj's */
426 idx = get_Proj_proj(src);
428 ins[idx] = get_CopyB_dst(p);
429 mem = get_CopyB_mem(p);
431 /* get rid of the CopyB */
432 turn_into_tuple(p, pn_CopyB_max);
433 set_Tuple_pred(p, pn_CopyB_M_regular, mem);
434 set_Tuple_pred(p, pn_CopyB_M_except, get_irg_bad(irg));
435 set_Tuple_pred(p, pn_CopyB_X_except, get_irg_bad(irg));
439 /* now create dummy entities for function with ignored return value */
440 if (n_args < n_com) {
441 ir_type *ctp = get_Call_type(entry->call);
444 if (is_lowered_type(ctp))
445 ctp = get_associated_type(ctp);
447 for (j = i = 0; i < get_method_n_ress(ctp); ++i) {
448 ir_type *rtp = get_method_res_type(ctp, i);
449 if (is_compound_type(rtp)) {
451 ins[j] = get_dummy_sel(irg, get_nodes_block(entry->call), rtp, env);
459 * Fix all calls on a call list by adding hidden parameters.
461 * @param irg the graph
462 * @param env the environment
464 static void fix_call_list(ir_graph *irg, wlk_env *env) {
465 const lower_params_t *lp = env->params;
467 ir_node *call, **new_in;
468 ir_type *ctp, *lowered_mtp;
469 add_hidden hidden_params;
470 int i, n_params, n_com, pos;
472 new_in = NEW_ARR_F(ir_node *, 0);
473 for (p = env->cl_list; p; p = p->next) {
475 ctp = get_Call_type(call);
476 lowered_mtp = create_modified_mtd_type(lp, ctp);
477 set_Call_type(call, lowered_mtp);
479 hidden_params = lp->hidden_params;
480 if (hidden_params == ADD_HIDDEN_SMART &&
481 get_method_variadicity(ctp) == variadicity_variadic)
482 hidden_params = ADD_HIDDEN_ALWAYS_IN_FRONT;
484 n_params = get_Call_n_params(call);
487 for (i = get_method_n_ress(ctp) - 1; i >= 0; --i) {
488 if (is_compound_type(get_method_res_type(ctp, i)))
492 ARR_RESIZE(ir_node *, new_in, n_params + n_com + pos);
493 memset(new_in, 0, sizeof(*new_in) * (n_params + n_com + pos));
494 if (hidden_params == ADD_HIDDEN_ALWAYS_IN_FRONT) {
495 add_hidden_param(irg, n_com, &new_in[pos], p, env);
498 /* copy all other parameters */
499 for (i = 0; i < n_params; ++i)
500 new_in[pos++] = get_Call_param(call, i);
501 if (hidden_params == ADD_HIDDEN_ALWAYS_LAST) {
502 add_hidden_param(irg, n_com, &new_in[pos], p, env);
505 new_in[0] = get_Call_mem(call);
506 new_in[1] = get_Call_ptr(call);
508 set_irn_in(call, n_params + n_com + 2, new_in);
513 * Transform a graph. If it has compound parameter returns,
514 * remove them and use the hidden parameter instead.
515 * If it calls methods with compound parameter returns, add hidden
518 * @param lp parameter struct
519 * @param irg the graph to transform
521 static void transform_irg(const lower_params_t *lp, ir_graph *irg)
523 ir_entity *ent = get_irg_entity(irg);
524 ir_type *mtp, *lowered_mtp, *tp, *ft;
525 int i, j, k, n_ress = 0, n_ret_com = 0, n_cr_opt;
526 ir_node **new_in, *ret, *endbl, *bl, *mem, *copy;
529 add_hidden hidden_params;
531 assert(ent && "Cannot tranform graph without an entity");
532 assert(get_irg_phase_state(irg) == phase_high && "call lowering must be done in phase high");
534 mtp = get_entity_type(ent);
536 if (lp->flags & LF_COMPOUND_RETURN) {
537 /* calculate the number of compound returns */
538 n_ress = get_method_n_ress(mtp);
539 for (n_ret_com = i = 0; i < n_ress; ++i) {
540 tp = get_method_res_type(mtp, i);
542 if (is_compound_type(tp))
548 /* much easier if we have only one return */
549 normalize_one_return(irg);
551 /* This graph has a compound argument. Create a new type */
552 lowered_mtp = create_modified_mtd_type(lp, mtp);
553 set_entity_type(ent, lowered_mtp);
555 hidden_params = lp->hidden_params;
556 if (hidden_params == ADD_HIDDEN_SMART &&
557 get_method_variadicity(mtp) == variadicity_variadic)
558 hidden_params = ADD_HIDDEN_ALWAYS_IN_FRONT;
560 if (hidden_params == ADD_HIDDEN_ALWAYS_IN_FRONT) {
561 /* hidden arguments are added first */
562 env.arg_shift = n_ret_com;
563 env.first_hidden = 0;
566 /* hidden arguments are added last */
568 env.first_hidden = get_method_n_params(mtp);
572 /* we must only search for calls */
575 obstack_init(&env.obst);
577 env.dummy_map = pmap_create_ex(8);
581 /* scan the code, fix argument numbers and collect calls. */
582 irg_walk_graph(irg, firm_clear_link, fix_args_and_collect_calls, &env);
586 fix_call_list(irg, &env);
590 * Now fix the Return node of the current graph.
593 /* STEP 1: find the return. This is simple, we have normalized the graph. */
594 endbl = get_irg_end_block(irg);
596 for (i = get_Block_n_cfgpreds(endbl) - 1; i >= 0; --i) {
597 ir_node *pred = get_Block_cfgpred(endbl, i);
599 if (is_Return(pred)) {
604 /* there should always be a return */
608 * STEP 2: fix it. For all compound return values add a CopyB,
609 * all others are copied.
611 NEW_ARR_A(ir_node *, new_in, n_ress + 1);
613 bl = get_nodes_block(ret);
614 mem = get_Return_mem(ret);
616 ft = get_irg_frame_type(irg);
617 NEW_ARR_A(cr_pair, cr_opt, n_ret_com);
619 for (j = 1, i = k = 0; i < n_ress; ++i) {
620 ir_node *pred = get_Return_res(ret, i);
621 tp = get_method_res_type(mtp, i);
623 if (is_compound_type(tp)) {
624 ir_node *arg = get_irg_args(irg);
625 arg = new_r_Proj(irg, get_nodes_block(arg), arg, mode_P_data, env.first_hidden + k);
628 if (is_compound_address(ft, pred)) {
629 /* we can do the copy-return optimization here */
630 cr_opt[n_cr_opt].ent = get_Sel_entity(pred);
631 cr_opt[n_cr_opt].arg = arg;
634 else { /* copy-return optimization is impossible, do the copy. */
642 mem = new_r_Proj(irg, bl, copy, mode_M, pn_CopyB_M_regular);
644 if (lp->flags & LF_RETURN_HIDDEN) {
649 else { /* scalar return value */
654 /* replace the in of the Return */
656 set_irn_in(ret, j, new_in);
659 irg_walk_graph(irg, NULL, do_copy_return_opt, cr_opt);
661 for (i = ARR_LEN(cr_opt) - 1; i >= 0; --i) {
662 remove_class_member(ft, cr_opt[i].ent);
665 } /* if (n_ret_com) */
667 pmap_destroy(env.dummy_map);
668 obstack_free(&env.obst, NULL);
672 * Returns non-zero if the given type is a method
673 * type that must be lowered.
675 * @param lp lowering parameters
676 * @param tp The type.
678 static int must_be_lowered(const lower_params_t *lp, ir_type *tp) {
682 if (is_Method_type(tp)) {
683 if (lp->flags & LF_COMPOUND_RETURN) {
684 /* check for compound returns */
685 n_ress = get_method_n_ress(tp);
686 for (i = 0; i < n_ress; ++i) {
687 res_tp = get_method_res_type(tp, i);
689 if (is_compound_type(res_tp))
698 * type-walker: lower all method types of entities
699 * and points-to types.
701 static void lower_method_types(type_or_ent *tore, void *env)
703 const lower_params_t *lp = env;
706 /* fix method entities */
707 if (is_entity(tore)) {
708 ir_entity *ent = (ir_entity *)tore;
709 tp = get_entity_type(ent);
711 if (must_be_lowered(lp, tp)) {
712 tp = create_modified_mtd_type(lp, tp);
713 set_entity_type(ent, tp);
717 tp = (ir_type *)tore;
719 /* fix pointer to methods */
720 if (is_Pointer_type(tp)) {
721 ir_type *etp = get_pointer_points_to_type(tp);
722 if (must_be_lowered(lp, etp)) {
723 etp = create_modified_mtd_type(lp, etp);
724 set_pointer_points_to_type(tp, etp);
731 * Lower calls with compound parameters and return types.
732 * This function does the following transformations:
734 * - Adds a new (hidden) pointer parameter for
735 * any return compound type.
737 * - Use of the hidden parameters in the function code.
739 * - Change all calls to functions with compound return
740 * by providing space for the hidden parameter on the callers
743 * - Replace a possible block copy after the function call.
745 void lower_calls_with_compounds(const lower_params_t *params)
749 lower_params_t param = *params;
751 if (param.find_pointer_type == NULL) {
752 param.find_pointer_type = def_find_pointer_type;
753 type_map = pmap_create_ex(8);
758 /* first step: Transform all graphs */
759 for (i = get_irp_n_irgs() - 1; i >= 0; --i) {
760 irg = get_irp_irg(i);
762 if (irg == get_const_code_irg())
765 transform_irg(¶m, irg);
768 /* second step: Lower all method types of visible entities */
769 type_walk(NULL, lower_method_types, ¶m);
772 pmap_destroy(type_map);