lower_calls.c 23.3 KB
Newer Older
Christian Würdig's avatar
Christian Würdig committed
1
/*
2
 * Copyright (C) 1995-2011 University of Karlsruhe.  All right reserved.
Christian Würdig's avatar
Christian Würdig committed
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
 *
 * This file is part of libFirm.
 *
 * This file may be distributed and/or modified under the terms of the
 * GNU General Public License version 2 as published by the Free Software
 * Foundation and appearing in the file LICENSE.GPL included in the
 * packaging of this file.
 *
 * Licensees holding valid libFirm Professional Edition licenses may use
 * this file in accordance with the libFirm Commercial License.
 * Agreement provided with the Software.
 *
 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE.
 */

Michael Beck's avatar
Michael Beck committed
20
21
22
/**
 * @file
 * @brief   Lowering of Calls with compound parameters and return types.
23
 * @author  Michael Beck, Matthias Braun
24
25
26
 */
#include "config.h"

27
28
29
#include <stdbool.h>

#include "lower_calls.h"
30
#include "lowering.h"
31
32
33
34
35
36
37
#include "irprog_t.h"
#include "irnode_t.h"
#include "type_t.h"
#include "irmode_t.h"
#include "ircons.h"
#include "irgmod.h"
#include "irgwalk.h"
38
#include "irmemory.h"
39
#include "irtools.h"
40
#include "iroptimize.h"
41
#include "array_t.h"
42
#include "pmap.h"
43
#include "error.h"
44

45
46
static pmap *pointer_types;
static pmap *lowered_mtps;
47
48
49
50
51

/**
 * Default implementation for finding a pointer type for a given element type.
 * Simple create a new one.
 */
52
static ir_type *get_pointer_type(ir_type *dest_type)
53
{
54
	ir_type *res = pmap_get(ir_type, pointer_types, dest_type);
55
56
57
	if (res == NULL) {
		res = new_type_pointer(dest_type);
		pmap_insert(pointer_types, dest_type, res);
58
59
	}
	return res;
60
}
61

62
63
64
static void fix_parameter_entities(ir_graph *irg, size_t n_compound_ret)
{
	ir_type *frame_type = get_irg_frame_type(irg);
65
	size_t   n_members  = get_compound_n_members(frame_type);
66
67
	size_t   i;

68
	for (i = 0; i < n_members; ++i) {
69
70
71
72
73
74
75
		ir_entity *member = get_compound_member(frame_type, i);
		size_t     num;
		if (!is_parameter_entity(member))
			continue;

		/* increase parameter number since we added a new parameter in front */
		num = get_entity_parameter_number(member);
76
77
		if (num == IR_VA_START_PARAMETER_NUMBER)
			continue;
78
79
80
81
		set_entity_parameter_number(member, num + n_compound_ret);
	}
}

82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
static void remove_compound_param_entities(ir_graph *irg)
{
	ir_type *frame_type = get_irg_frame_type(irg);
	size_t   n_members  = get_compound_n_members(frame_type);
	size_t   i;

	for (i = n_members; i > 0; ) {
		ir_entity *member = get_compound_member(frame_type, --i);
		ir_type   *type;
		if (!is_parameter_entity(member))
			continue;

		type = get_entity_type(member);
		if (is_compound_type(type)) {
			free_entity(member);
		}
	}
}

101
102
103
104
/**
 * Creates a new lowered type for a method type with compound
 * arguments. The new type is associated to the old one and returned.
 */
105
static ir_type *lower_mtp(compound_call_lowering_flags flags, ir_type *mtp)
106
{
107
108
109
110
111
112
113
114
115
	bool      must_be_lowered = false;
	ir_type  *lowered;
	ir_type **params;
	ir_type **results;
	size_t    n_ress;
	size_t    n_params;
	size_t    nn_ress;
	size_t    nn_params;
	size_t    i;
116
	unsigned  cconv;
117
	mtp_additional_properties mtp_properties;
118
119
120
121

	if (!is_Method_type(mtp))
		return mtp;

122
	lowered = pmap_get(ir_type, lowered_mtps, mtp);
123
	if (lowered != NULL)
124
125
		return lowered;

126
	/* check if the type has to be lowered at all */
127
128
	n_params = get_method_n_params(mtp);
	n_ress   = get_method_n_ress(mtp);
129
130
131
132
133
	for (i = 0; i < n_ress; ++i) {
		ir_type *res_tp = get_method_res_type(mtp, i);
		if (is_compound_type(res_tp)) {
			must_be_lowered = true;
			break;
134
		}
135
	}
136
137
138
139
140
141
142
143
144
	if (!must_be_lowered && !(flags & LF_DONT_LOWER_ARGUMENTS)) {
		for (i = 0; i < n_params; ++i) {
			ir_type *param_type = get_method_param_type(mtp, i);
			if (is_compound_type(param_type)) {
				must_be_lowered = true;
				break;
			}
		}
	}
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
	if (!must_be_lowered)
		return mtp;

	results   = ALLOCANZ(ir_type*, n_ress);
	params    = ALLOCANZ(ir_type*, n_params + n_ress);
	nn_ress   = 0;
	nn_params = 0;

	/* add a hidden parameter in front for every compound result */
	for (i = 0; i < n_ress; ++i) {
		ir_type *res_tp = get_method_res_type(mtp, i);

		if (is_compound_type(res_tp)) {
			/* this compound will be allocated on callers stack and its
			   address will be transmitted as a hidden parameter. */
			ir_type *ptr_tp = get_pointer_type(res_tp);
			params[nn_params++] = ptr_tp;
			if (flags & LF_RETURN_HIDDEN)
				results[nn_ress++] = ptr_tp;
		} else {
			/* scalar result */
			results[nn_ress++] = res_tp;
167
168
		}
	}
169
170
	/* copy over parameter types */
	for (i = 0; i < n_params; ++i) {
171
172
173
174
175
176
177
		ir_type *param_type = get_method_param_type(mtp, i);
		if (! (flags & LF_DONT_LOWER_ARGUMENTS)
		    && is_compound_type(param_type)) {
		    /* turn parameter into a pointer type */
		    param_type = new_type_pointer(param_type);
		}
		params[nn_params++] = param_type;
178
179
180
	}
	assert(nn_ress <= n_ress);
	assert(nn_params <= n_params + n_ress);
181
182

	/* create the new type */
183
	lowered = new_d_type_method(nn_params, nn_ress, get_type_dbg_info(mtp));
184
185
186
187
188
189
190

	/* fill it */
	for (i = 0; i < nn_params; ++i)
		set_method_param_type(lowered, i, params[i]);
	for (i = 0; i < nn_ress; ++i)
		set_method_res_type(lowered, i, results[i]);

191
	set_method_variadicity(lowered, get_method_variadicity(mtp));
192

193
194
195
196
197
198
	cconv = get_method_calling_convention(mtp);
	if (nn_params > n_params) {
		cconv |= cc_compound_ret;
	}
	set_method_calling_convention(lowered, cconv);

199
200
201
202
203
	mtp_properties = get_method_additional_properties(mtp);
	/* after lowering the call is not const anymore, since it writes to the
	 * memory for the return value passed to it */
	mtp_properties &= ~mtp_property_const;
	set_method_additional_properties(lowered, mtp_properties);
204

205
	/* associate the lowered type with the original one for easier access */
206
	set_higher_type(lowered, mtp);
207
	pmap_insert(lowered_mtps, mtp, lowered);
208
209

	return lowered;
210
211
212
}

/**
213
214
215
216
 * A call list entry.
 */
typedef struct cl_entry cl_entry;
struct cl_entry {
217
218
219
	cl_entry *next;   /**< Pointer to the next entry. */
	ir_node  *call;   /**< Pointer to the Call node. */
	ir_node  *copyb;  /**< List of all CopyB nodes. */
220
221
	bool      has_compound_ret   : 1;
	bool      has_compound_param : 1;
222
223
224
225
};

/**
 * Walker environment for fix_args_and_collect_calls().
226
 */
227
typedef struct wlk_env_t {
Michael Beck's avatar
Michael Beck committed
228
	size_t               arg_shift;        /**< The Argument index shift for parameters. */
229
230
	struct obstack       obst;             /**< An obstack to allocate the data on. */
	cl_entry             *cl_list;         /**< The call list. */
231
	compound_call_lowering_flags flags;
232
	ir_type              *lowered_mtp;     /**< The lowered method type of the current irg if any. */
233
234
	bool                  only_local_mem:1;/**< Set if only local memory access was found. */
	bool                  changed:1;       /**< Set if the current graph was changed. */
235
236
237
} wlk_env;

/**
238
239
240
241
242
243
244
 * Return the call list entry of a call node.
 * If no entry exists yet, allocate one and enter the node into
 * the call list of the environment.
 *
 * @param call   A Call node.
 * @param env    The environment.
 */
245
static cl_entry *get_call_entry(ir_node *call, wlk_env *env)
246
{
247
	cl_entry *res = (cl_entry*)get_irn_link(call);
248
	if (res == NULL) {
249
		res = OALLOC(&env->obst, cl_entry);
250
251
252
253
254
255
256
		res->next  = env->cl_list;
		res->call  = call;
		res->copyb = NULL;
		set_irn_link(call, res);
		env->cl_list = res;
	}
	return res;
257
258
259
}

/**
260
261
262
263
264
265
 * Finds the base address of an address by skipping Sel's and address
 * calculation.
 *
 * @param adr   the address
 * @param pEnt  points to the base entity if any
 */
266
267
static ir_node *find_base_adr(ir_node *ptr, ir_entity **pEnt)
{
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
	ir_entity *ent = NULL;
	assert(mode_is_reference(get_irn_mode(ptr)));

	for (;;) {
		if (is_Sel(ptr)) {
			ent = get_Sel_entity(ptr);
			ptr = get_Sel_ptr(ptr);
		}
		else if (is_Add(ptr)) {
			ir_node *left = get_Add_left(ptr);
			if (mode_is_reference(get_irn_mode(left)))
				ptr = left;
			else
				ptr = get_Add_right(ptr);
			ent = NULL;
		} else if (is_Sub(ptr)) {
			ptr = get_Sub_left(ptr);
			ent = NULL;
		} else {
			*pEnt = ent;
			return ptr;
		}
	}
}

/**
 * Check if a given pointer represents non-local memory.
 */
296
297
static void check_ptr(ir_node *ptr, wlk_env *env)
{
298
299
300
301
302
	ir_storage_class_class_t sc;
	ir_entity                *ent;

	/* still alias free */
	ptr = find_base_adr(ptr, &ent);
303
	sc  = get_base_sc(classify_pointer(ptr, ent));
304
305
	if (sc != ir_sc_localvar && sc != ir_sc_malloced) {
		/* non-local memory access */
306
		env->only_local_mem = false;
307
308
309
	}
}

310
311
312
313
314
315
316
317
318
319
320
321
/*
 * Returns non-zero if a Call is surely a self-recursive Call.
 * Beware: if this functions returns 0, the call might be self-recursive!
 */
static bool is_self_recursive_Call(const ir_node *call)
{
	const ir_node *callee = get_Call_ptr(call);

	if (is_SymConst_addr_ent(callee)) {
		const ir_entity *ent = get_SymConst_entity(callee);
		const ir_graph  *irg = get_entity_irg(ent);
		if (irg == get_irn_irg(call))
322
			return true;
323
	}
324
	return false;
325
326
}

327
328
/**
 * Post walker: shift all parameter indexes
329
 * and collect Calls with compound returns in the call list.
330
331
 * If a non-alias free memory access is found, reset the alias free
 * flag.
332
 */
333
334
static void fix_args_and_collect_calls(ir_node *n, void *ctx)
{
335
	wlk_env *env = (wlk_env*)ctx;
336
337
338
339
340
341
342
343
344
345
346
347
348
	ir_node *ptr;

	switch (get_irn_opcode(n)) {
	case iro_Load:
	case iro_Store:
		if (env->only_local_mem) {
			ptr = get_irn_n(n, 1);
			check_ptr(ptr, env);
		}
		break;
	case iro_Proj:
		if (env->arg_shift > 0) {
			ir_node *pred = get_Proj_pred(n);
349
			ir_graph *irg = get_irn_irg(n);
350
351

			/* Fix the argument numbers */
352
			if (pred == get_irg_args(irg)) {
353
354
				long pnr = get_Proj_proj(n);
				set_Proj_proj(n, pnr + env->arg_shift);
355
				env->changed = true;
356
357
358
			}
		}
		break;
359
	case iro_Call: {
360
361
362
363
		ir_type *ctp      = get_Call_type(n);
		size_t   n_ress   = get_method_n_ress(ctp);
		size_t   n_params = get_method_n_params(ctp);
		size_t   i;
364
365
		if (! is_self_recursive_Call(n)) {
			/* any non self recursive call might access global memory */
366
			env->only_local_mem = false;
367
		}
368

369
		/* check for compound returns */
370
371
372
		for (i = 0; i < n_ress; ++i) {
			ir_type *type = get_method_res_type(ctp, i);
			if (is_compound_type(type)) {
373
374
375
376
				/*
				 * This is a call with a compound return. As the result
				 * might be ignored, we must put it in the list.
				 */
377
378
379
380
381
382
383
384
385
386
				cl_entry *entry = get_call_entry(n, env);
				entry->has_compound_ret = true;
				break;
			}
		}
		for (i = 0; i < n_params; ++i) {
			ir_type *type = get_method_param_type(ctp, i);
			if (is_compound_type(type)) {
				cl_entry *entry = get_call_entry(n, env);
				entry->has_compound_param = true;
387
				break;
388
389
			}
		}
390
		break;
391
392
393
	}
	case iro_CopyB: {
		ir_node *src = get_CopyB_src(n);
394
395
396
397
398
		if (env->only_local_mem) {
			check_ptr(get_CopyB_src(n), env);
			if (env->only_local_mem)
				check_ptr(get_CopyB_dst(n), env);
		}
399
400
401
402
403
404
		/* check for compound returns */
		if (is_Proj(src)) {
			ir_node *proj = get_Proj_pred(src);
			if (is_Proj(proj) && get_Proj_proj(proj) == pn_Call_T_result) {
				ir_node *call = get_Proj_pred(proj);
				if (is_Call(call)) {
405
					ir_type *ctp = get_Call_type(call);
406
407
					if (is_compound_type(get_method_res_type(ctp, get_Proj_proj(src)))) {
						/* found a CopyB from compound Call result */
408
						cl_entry *e = get_call_entry(call, env);
409
410
						set_irn_link(n, e->copyb);
						e->copyb = n;
411
412
413
					}
				}
			}
414
		}
415
		break;
416
	}
417
	case iro_Sel: {
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
		ir_entity *entity = get_Sel_entity(n);
		ir_type   *type   = get_entity_type(entity);

		if (is_parameter_entity(entity) && is_compound_type(type)) {
			if (! (env->flags & LF_DONT_LOWER_ARGUMENTS)) {
				/* note that num was already modified by fix_parameter_entities
				 * so no need to add env->arg_shift again */
				size_t num = get_entity_parameter_number(entity);
				ir_graph *irg  = get_irn_irg(n);
				ir_node  *args = get_irg_args(irg);
				ir_node  *ptr  = new_r_Proj(args, mode_P, num);
				exchange(n, ptr);
				/* hack to avoid us visiting the proj again */
				mark_irn_visited(ptr);
			}
433

434
435
			/* we need to copy compound parameters */
			env->only_local_mem = false;
436
437
438
		}
		break;
	}
439
440
441
	default:
		/* do nothing */
		break;
442
	}
443
444
445
}

/**
446
447
 * Returns non-zero if a node is a compound address
 * of a frame-type entity.
448
449
450
451
 *
 * @param ft   the frame type
 * @param adr  the node
 */
452
static bool is_compound_address(ir_type *ft, ir_node *adr)
453
{
454
455
456
	ir_entity *ent;

	if (! is_Sel(adr))
457
		return false;
458
	if (get_Sel_n_indexs(adr) != 0)
459
		return false;
460
461
	ent = get_Sel_entity(adr);
	return get_entity_owner(ent) == ft;
462
463
}

464
/** A pair for the copy-return-optimization. */
465
typedef struct cr_pair {
466
467
	ir_entity *ent; /**< the entity than can be removed from the frame */
	ir_node *arg;   /**< the argument that replaces the entities address */
468
469
470
471
472
473
} cr_pair;

/**
 * Post walker: fixes all entities addresses for the copy-return
 * optimization.
 *
yb9976's avatar
yb9976 committed
474
 * Note: We expect the length of the cr_pair array (i.e. number of compound
475
476
 * return values) to be 1 (C, C++) in almost all cases, so ignore the
 * linear search complexity here.
477
 */
478
479
static void do_copy_return_opt(ir_node *n, void *ctx)
{
480
481
	if (is_Sel(n)) {
		ir_entity *ent = get_Sel_entity(n);
482
483
		cr_pair   *arr = (cr_pair*)ctx;
		size_t    i, l;
484

485
		for (i = 0, l = ARR_LEN(arr); i < l; ++i) {
486
487
488
489
490
491
			if (ent == arr[i].ent) {
				exchange(n, arr[i].arg);
				break;
			}
		}
	}
492
493
494
}

/**
495
496
497
498
499
500
 * Return a Sel node that selects a dummy argument of type tp.
 *
 * @param irg    the graph
 * @param block  the block where a newly create Sel should be placed
 * @param tp     the type of the dummy entity that should be create
 */
501
static ir_node *get_dummy_sel(ir_graph *irg, ir_node *block, ir_type *tp)
502
{
503
504
505
506
507
508
509
	ir_type   *ft       = get_irg_frame_type(irg);
	ident     *dummy_id = id_unique("dummy.%u");
	ir_entity *ent      = new_entity(ft, dummy_id, tp);

	if (get_type_state(ft) == layout_fixed) {
		/* Fix the layout again */
		panic("Fixed layout not implemented");
510
	}
511

512
	return new_r_simpleSel(block, get_irg_no_mem(irg), get_irg_frame(irg), ent);
513
514
515
516
517
}

/**
 * Add the hidden parameter from the CopyB node to the Call node.
 */
518
static void add_hidden_param(ir_graph *irg, size_t n_com, ir_node **ins,
519
                             cl_entry *entry, ir_type *ctp)
520
{
521
	ir_node *p, *n;
Michael Beck's avatar
Michael Beck committed
522
	size_t n_args;
523
524
525

	n_args = 0;
	for (p = entry->copyb; p; p = n) {
526
527
528
		ir_node *src = get_CopyB_src(p);
		size_t   idx = get_Proj_proj(src);
		n = (ir_node*)get_irn_link(p);
529

530
531
532
533
534
535
536
537
538
539
540
541
542
		/* consider only the first CopyB */
		if (ins[idx] == NULL) {
			ir_node *block = get_nodes_block(p);

			/* use the memory output of the call and not the input of the CopyB
			 * otherwise stuff breaks if the call was mtp_property_const, because
			 * then the copyb skips the call. But after lowering the call is not
			 * const anymore, and its memory has to be used */
			ir_node *mem = new_r_Proj(entry->call, mode_M, pn_Call_M);

			ins[idx] = get_CopyB_dst(p);

			/* get rid of the CopyB */
543
544
545
546
547
548
549
550
551
			if (ir_throws_exception(p)) {
				turn_into_tuple(p, pn_CopyB_max+1);
				set_Tuple_pred(p, pn_CopyB_M,         mem);
				set_Tuple_pred(p, pn_CopyB_X_regular, new_r_Jmp(block));
				set_Tuple_pred(p, pn_CopyB_X_except,  new_r_Bad(irg, mode_X));
			} else {
				turn_into_tuple(p, pn_CopyB_M+1);
				set_Tuple_pred(p, pn_CopyB_M, mem);
			}
552
553
			++n_args;
		}
554
555
556
557
	}

	/* now create dummy entities for function with ignored return value */
	if (n_args < n_com) {
558
559
		size_t i;
		size_t j;
560
561
562
563
564

		for (j = i = 0; i < get_method_n_ress(ctp); ++i) {
			ir_type *rtp = get_method_res_type(ctp, i);
			if (is_compound_type(rtp)) {
				if (ins[j] == NULL)
565
					ins[j] = get_dummy_sel(irg, get_nodes_block(entry->call), rtp);
566
567
568
569
				++j;
			}
		}
	}
570
571
}

572
static void fix_compound_ret(cl_entry *entry, ir_type *ctp)
573
{
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
	ir_node  *call     = entry->call;
	ir_graph *irg      = get_irn_irg(call);
	size_t    n_params = get_Call_n_params(call);
	size_t    n_com    = 0;
	size_t    n_res    = get_method_n_ress(ctp);
	size_t    pos      = 0;
	ir_node **new_in;
	size_t    i;

	for (i = 0; i < n_res; ++i) {
		ir_type *type = get_method_res_type(ctp, i);
		if (is_compound_type(type))
			++n_com;
	}

	new_in = ALLOCANZ(ir_node*, n_params + n_com + (n_Call_max+1));
	new_in[pos++] = get_Call_mem(call);
	new_in[pos++] = get_Call_ptr(call);
	assert(pos == n_Call_max+1);
593
	add_hidden_param(irg, n_com, &new_in[pos], entry, ctp);
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
	pos += n_com;

	/* copy all other parameters */
	for (i = 0; i < n_params; ++i) {
		ir_node *param = get_Call_param(call, i);
		new_in[pos++] = param;
	}
	assert(pos == n_params+n_com+(n_Call_max+1));
	set_irn_in(call, pos, new_in);
}

static ir_entity *create_compound_arg_entitiy(ir_graph *irg, ir_type *type)
{
	ir_type   *frame  = get_irg_frame_type(irg);
	ident     *id     = id_unique("$compound_param.%u");
	ir_entity *entity = new_entity(frame, id, type);
	/* TODO:
	 * we could do some optimisations here and create a big union type for all
	 * different call types in a function */
	return entity;
}

static void fix_compound_params(cl_entry *entry, ir_type *ctp)
{
	ir_node  *call     = entry->call;
	dbg_info *dbgi     = get_irn_dbg_info(call);
	ir_node  *mem      = get_Call_mem(call);
	ir_graph *irg      = get_irn_irg(call);
	ir_node  *nomem    = new_r_NoMem(irg);
	ir_node  *frame    = get_irg_frame(irg);
	size_t    n_params = get_method_n_params(ctp);
	size_t    i;
626

627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
	for (i = 0; i < n_params; ++i) {
		ir_type   *type = get_method_param_type(ctp, i);
		ir_node   *block;
		ir_node   *arg;
		ir_node   *sel;
		ir_node   *copyb;
		ir_entity *arg_entity;
		if (!is_compound_type(type))
			continue;

		arg        = get_Call_param(call, i);
		arg_entity = create_compound_arg_entitiy(irg, type);
		block      = get_nodes_block(call);
		sel        = new_rd_simpleSel(dbgi, block, nomem, frame, arg_entity);
		copyb      = new_rd_CopyB(dbgi, block, mem, sel, arg, type);
		mem        = new_r_Proj(copyb, mode_M, pn_CopyB_M);
		set_Call_param(call, i, sel);
	}
	set_Call_mem(call, mem);
}

static void fix_calls(wlk_env *env)
{
	cl_entry *entry;
	for (entry = env->cl_list; entry; entry = entry->next) {
		ir_node *call        = entry->call;
		ir_type *ctp         = get_Call_type(call);
		ir_type *lowered_mtp = lower_mtp(env->flags, ctp);
		set_Call_type(call, lowered_mtp);
656

657
658
659
660
		if (entry->has_compound_param) {
			fix_compound_params(entry, ctp);
		}
		if (entry->has_compound_ret) {
661
			fix_compound_ret(entry, ctp);
662
663
		}
	}
664
665
666
667
668
669
670
671
}

/**
 * Transform a graph. If it has compound parameter returns,
 * remove them and use the hidden parameter instead.
 * If it calls methods with compound parameter returns, add hidden
 * parameters.
 *
672
673
 * @param irg  the graph to transform
 */
674
static void transform_irg(compound_call_lowering_flags flags, ir_graph *irg)
675
{
676
677
678
679
680
681
682
683
684
685
686
687
688
	ir_entity *ent         = get_irg_entity(irg);
	ir_type   *mtp         = get_entity_type(ent);
	size_t     n_ress      = get_method_n_ress(mtp);
	size_t     n_params    = get_method_n_params(mtp);
	size_t     n_ret_com   = 0;
	size_t     n_param_com = 0;

	ir_type   *lowered_mtp, *tp, *ft;
	size_t    i, j, k;
	size_t    n_cr_opt;
	ir_node   **new_in, *ret, *endbl, *bl, *mem, *copy;
	cr_pair   *cr_opt;
	wlk_env   env;
689

690
691
	/* calculate the number of compound returns */
	for (n_ret_com = i = 0; i < n_ress; ++i) {
692
693
		ir_type *type = get_method_res_type(mtp, i);
		if (is_compound_type(type))
694
			++n_ret_com;
695
	}
696
697
698
699
700
	for (i = 0; i < n_params; ++i) {
		ir_type *type = get_method_param_type(mtp, i);
		if (is_compound_type(type))
			++n_param_com;
	}
701

702
703
	if (n_ret_com > 0)
		fix_parameter_entities(irg, n_ret_com);
704

705
706
707
708
709
	if (n_ret_com) {
		/* much easier if we have only one return */
		normalize_one_return(irg);

		/* This graph has a compound argument. Create a new type */
710
		lowered_mtp = lower_mtp(flags, mtp);
711
712
		set_entity_type(ent, lowered_mtp);

713
		/* hidden arguments are added first */
714
		env.arg_shift = n_ret_com;
715
716
717
	} else {
		/* we must only search for calls */
		env.arg_shift = 0;
718
		lowered_mtp   = NULL;
719
720
	}
	obstack_init(&env.obst);
721
	env.cl_list        = NULL;
722
	env.flags          = flags;
723
	env.lowered_mtp    = lowered_mtp;
724
725
	env.only_local_mem = true;
	env.changed        = false;
726
727

	/* scan the code, fix argument numbers and collect calls. */
728
729
	irg_walk_graph(irg, firm_clear_link, NULL, &env);
	irg_walk_graph(irg, fix_args_and_collect_calls, NULL, &env);
730

731
732
733
	if (n_param_com > 0 && !(flags & LF_DONT_LOWER_ARGUMENTS))
		remove_compound_param_entities(irg);

734
	/* fix all calls */
735
736
737
	if (env.cl_list != NULL) {
		fix_calls(&env);
		env.changed = true;
738
739
740
	}

	if (n_ret_com) {
Michael Beck's avatar
Michael Beck committed
741
742
		int idx;

743
744
745
		/* STEP 1: find the return. This is simple, we have normalized the graph. */
		endbl = get_irg_end_block(irg);
		ret = NULL;
Michael Beck's avatar
Michael Beck committed
746
747
		for (idx = get_Block_n_cfgpreds(endbl) - 1; idx >= 0; --idx) {
			ir_node *pred = get_Block_cfgpred(endbl, idx);
748
749
750
751
752
753

			if (is_Return(pred)) {
				ret = pred;
				break;
			}
		}
Andreas Zwinkau's avatar
Andreas Zwinkau committed
754
755

		/* in case of infinite loops, there might be no return */
Andreas Zwinkau's avatar
Andreas Zwinkau committed
756
757
758
759
		if (ret != NULL) {
			/*
			 * Now fix the Return node of the current graph.
			 */
760
			env.changed = true;
Andreas Zwinkau's avatar
Andreas Zwinkau committed
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779

			/*
			 * STEP 2: fix it. For all compound return values add a CopyB,
			 * all others are copied.
			 */
			NEW_ARR_A(ir_node *, new_in, n_ress + 1);

			bl  = get_nodes_block(ret);
			mem = get_Return_mem(ret);

			ft = get_irg_frame_type(irg);
			NEW_ARR_A(cr_pair, cr_opt, n_ret_com);
			n_cr_opt = 0;
			for (j = 1, i = k = 0; i < n_ress; ++i) {
				ir_node *pred = get_Return_res(ret, i);
				tp = get_method_res_type(mtp, i);

				if (is_compound_type(tp)) {
					ir_node *arg = get_irg_args(irg);
780
					arg = new_r_Proj(arg, mode_P_data, k);
Andreas Zwinkau's avatar
Andreas Zwinkau committed
781
782
783
					++k;

					if (is_Unknown(pred)) {
784
785
						/* The Return(Unknown) is the Firm construct for a
						 * missing return. Do nothing. */
Andreas Zwinkau's avatar
Andreas Zwinkau committed
786
787
					} else {
						/**
788
789
790
						 * Sorrily detecting that copy-return is possible isn't
						 * that simple. We must check, that the hidden address
						 * is alias free during the whole function.
Andreas Zwinkau's avatar
Andreas Zwinkau committed
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
						 * A simple heuristic: all Loads/Stores inside
						 * the function access only local frame.
						 */
						if (env.only_local_mem && is_compound_address(ft, pred)) {
							/* we can do the copy-return optimization here */
							cr_opt[n_cr_opt].ent = get_Sel_entity(pred);
							cr_opt[n_cr_opt].arg = arg;
							++n_cr_opt;
						} else { /* copy-return optimization is impossible, do the copy. */
							copy = new_r_CopyB(
									bl,
									mem,
									arg,
									pred,
									tp
									);
							mem = new_r_Proj(copy, mode_M, pn_CopyB_M);
						}
809
					}
810
					if (flags & LF_RETURN_HIDDEN) {
Andreas Zwinkau's avatar
Andreas Zwinkau committed
811
812
813
814
815
						new_in[j] = arg;
						++j;
					}
				} else { /* scalar return value */
					new_in[j] = pred;
816
817
818
					++j;
				}
			}
Andreas Zwinkau's avatar
Andreas Zwinkau committed
819
820
821
			/* replace the in of the Return */
			new_in[0] = mem;
			set_irn_in(ret, j, new_in);
822

Andreas Zwinkau's avatar
Andreas Zwinkau committed
823
			if (n_cr_opt > 0) {
824
825
				size_t c;
				size_t n;
826

Andreas Zwinkau's avatar
Andreas Zwinkau committed
827
				irg_walk_graph(irg, NULL, do_copy_return_opt, cr_opt);
828

829
830
				for (c = 0, n = ARR_LEN(cr_opt); c < n; ++c) {
					free_entity(cr_opt[c].ent);
Andreas Zwinkau's avatar
Andreas Zwinkau committed
831
				}
832
833
			}
		}
834
	}
835
836

	obstack_free(&env.obst, NULL);
837
}
838

839
static void lower_method_types(type_or_ent tore, void *env)
840
{
841
842
	const compound_call_lowering_flags *flags
		= (const compound_call_lowering_flags*)env;
843
844

	/* fix method entities */
845
	if (is_entity(tore.ent)) {
846
847
848
849
		ir_entity *ent     = tore.ent;
		ir_type   *tp      = get_entity_type(ent);
		ir_type   *lowered = lower_mtp(*flags, tp);
		set_entity_type(ent, lowered);
850
	} else {
851
		ir_type *tp = tore.typ;
852
853
854

		/* fix pointer to methods */
		if (is_Pointer_type(tp)) {
855
856
857
			ir_type *points_to         = get_pointer_points_to_type(tp);
			ir_type *lowered_points_to = lower_mtp(*flags, points_to);
			set_pointer_points_to_type(tp, lowered_points_to);
858
859
		}
	}
860
861
}

862
void lower_calls_with_compounds(compound_call_lowering_flags flags)
863
{
Michael Beck's avatar
Michael Beck committed
864
	size_t i, n;
865

866
867
	pointer_types = pmap_create();
	lowered_mtps = pmap_create();
868

869
	/* first step: Transform all graphs */
Michael Beck's avatar
Michael Beck committed
870
	for (i = 0, n = get_irp_n_irgs(); i < n; ++i) {
871
872
		ir_graph *irg = get_irp_irg(i);
		transform_irg(flags, irg);
873
	}
874

875
	/* second step: Lower all method types of visible entities */
876
	type_walk(NULL, lower_method_types, &flags);
877

878
879
	pmap_destroy(lowered_mtps);
	pmap_destroy(pointer_types);
880
}