summaryrefslogtreecommitdiffhomepage
path: root/ir/ana/analyze_irg_args.c
blob: bbd8fb193a0c0ab50b8141d99459f64650b54d3c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
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
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
/*
 * This file is part of libFirm.
 * Copyright (C) 2012 University of Karlsruhe.
 */

/**
 * @file
 * @brief      read/write analyze of graph argument, which have mode reference.
 * @author     Beyhan Veliev
 */
#include "analyze_irg_args.h"

#include "array.h"
#include "cgana.h"
#include "entity_t.h"
#include "irmode_t.h"
#include "irnode_t.h"
#include "irouts_t.h"
#include "irprog.h"
#include "util.h"
#include <stdlib.h>

/**
 * Walk recursive the successors of a graph argument
 * with mode reference and mark if it will be read,
 * written or stored.
 *
 * @param arg   The graph argument with mode reference,
 *             that must be checked.
 */
static ptr_access_kind analyze_arg(ir_node *arg, ptr_access_kind bits)
{
	/* We must visit a node once to avoid endless recursion.*/
	mark_irn_visited(arg);

	foreach_irn_out_r(arg, i, succ) {
		if (irn_visited(succ))
			continue;

		/* We should not walk over the memory edge.*/
		if (get_irn_mode(succ) == mode_M)
			continue;

		/* If we reach with the recursion a Call node and our reference
		   isn't the address of this Call we accept that the reference will
		   be read and written if the graph of the method represented by
		   "Call" isn't computed else we analyze that graph. If our
		   reference is the address of this
		   Call node that mean the reference will be read.*/
		switch (get_irn_opcode(succ)) {

		case iro_Call: {
			ir_node *ptr = get_Call_ptr(succ);

			if (ptr == arg) {
				/* Hmm: not sure what this is, most likely a read */
				bits |= ptr_access_read;
			} else {
				ir_entity *callee = get_Call_callee(succ);

				if (callee != NULL) {
					for (int p = get_Call_n_params(succ); p-- > 0; ) {
						if (get_Call_param(succ, p) == arg) {
							/* an arg can be used more than once ! */
							bits |= get_method_param_access(callee, p);
						}
					}
				} else if (is_Member(ptr) && get_irp_callee_info_state() == irg_callee_info_consistent) {
					/* is be a polymorphic call but callee information is available */
					size_t n_params = get_Call_n_params(succ);

					/* simply look into ALL possible callees */
					for (int c = cg_get_call_n_callees(succ); c-- > 0; ) {
						ir_entity *meth_ent = cg_get_call_callee(succ, c);

						/* unknown_entity is used to signal that we don't know what is called */
						if (is_unknown_entity(meth_ent)) {
							bits |= ptr_access_all;
							break;
						}

						for (size_t p = n_params; p-- > 0; ) {
							if (get_Call_param(succ, p) == arg) {
								/* an arg can be used more than once ! */
								bits |= get_method_param_access(meth_ent, p);
							}
						}
					}
				} else /* can do anything */
					bits |= ptr_access_all;
			}

			/* search stops here anyway */
			continue;
		}
		case iro_Store:
			/* We have reached a Store node => the reference is written or stored. */
			if (get_Store_ptr(succ) == arg) {
				/* written to */
				bits |= ptr_access_write;
			} else {
				/* stored itself */
				bits |= ptr_access_store;
			}

			/* search stops here anyway */
			continue;

		case iro_Load:
			/* We have reached a Load node => the reference is read. */
			bits |= ptr_access_read;

			/* search stops here anyway */
			continue;

		case iro_Conv:
			/* our address is casted into something unknown. Break our search. */
			bits = ptr_access_all;
			break;

		default:
			break;
		}

		/* If we know that, the argument will be read, write and stored, we
		   can break the recursion.*/
		if (bits == ptr_access_all) {
			bits = ptr_access_all;
			break;
		}

		/*
		 * A calculation that do not lead to a reference mode ends our search.
		 * This is dangerous: It would allow to cast into integer and that cast back ...
		 * so, when we detect a Conv we go mad, see the Conv case above.
		 */
		if (!mode_is_reference(get_irn_mode(succ)))
			continue;

		/* follow further the address calculation */
		bits = analyze_arg(succ, bits);
	}
	return bits;
}

/**
 * Check if a argument of the ir graph with mode
 * reference is read, write or both.
 *
 * @param irg   The ir graph to analyze.
 */
static void analyze_ent_args(ir_entity *ent)
{
	ir_type *mtp     = get_entity_type(ent);
	size_t   nparams = get_method_n_params(mtp);

	ent->attr.mtd_attr.param_access = NEW_ARR_F(ptr_access_kind, nparams);

	/* If the method haven't parameters we have
	 * nothing to do.
	 */
	if (nparams <= 0)
		return;

  /* we have not yet analyzed the graph, set ALL access for pointer args */
	for (size_t i = nparams; i-- > 0; ) {
		ir_type *type = get_method_param_type(mtp, i);
		ent->attr.mtd_attr.param_access[i] = is_Pointer_type(type) ? ptr_access_all : ptr_access_none;
	}

	ir_graph *irg = get_entity_irg(ent);
	if (irg == NULL) {
		/* no graph, no better info */
		return;
	}

	assure_irg_outs(irg);
	ir_node *irg_args = get_irg_args(irg);

	/* A array to save the information for each argument with
	   mode reference.*/
	ptr_access_kind *rw_info = ALLOCAN(ptr_access_kind, nparams);

	/* We initialize the element with none state. */
	for (size_t i = nparams; i-- > 0; )
		rw_info[i] = ptr_access_none;

	/* search for arguments with mode reference
	   to analyze them.*/
	foreach_irn_out_r(irg_args, i, arg) {
		ir_mode *arg_mode = get_irn_mode(arg);
		unsigned proj_nr  = get_Proj_num(arg);

		if (mode_is_reference(arg_mode))
			rw_info[proj_nr] |= analyze_arg(arg, rw_info[proj_nr]);
	}

	/* copy the temporary info */
	MEMCPY(ent->attr.mtd_attr.param_access, rw_info, nparams);
}

void analyze_irg_args(ir_graph *irg)
{
	if (irg == get_const_code_irg())
		return;

	ir_entity *entity = get_irg_entity(irg);
	if (entity == NULL)
		return;

	if (!entity->attr.mtd_attr.param_access)
		analyze_ent_args(entity);
}

ptr_access_kind get_method_param_access(ir_entity *ent, size_t pos)
{
#ifndef NDEBUG
	ir_type *mtp = get_entity_type(ent);
	assert(is_method_variadic(mtp) || pos < get_method_n_params(mtp));
#endif

	if (ent->attr.mtd_attr.param_access) {
		if (pos < ARR_LEN(ent->attr.mtd_attr.param_access))
			return ent->attr.mtd_attr.param_access[pos];
		else
			return ptr_access_all;
	}

	analyze_ent_args(ent);

	if (pos < ARR_LEN(ent->attr.mtd_attr.param_access))
		return ent->attr.mtd_attr.param_access[pos];
	else
		return ptr_access_all;
}

/* Weights for parameters */
enum args_weight {
	null_weight          = 0,   /**< If can't be anything optimized. */
	binop_weight         = 1,   /**< If the argument have mode_weight and take part in binop. */
	const_binop_weight   = 1,   /**< If the argument have mode_weight and take part in binop with a constant.*/
	cmp_weight           = 4,   /**< If the argument take part in cmp. */
	const_cmp_weight     = 10,  /**< If the argument take part in cmp with a constant. */
	indirect_call_weight = 125, /**< If the argument is the address of an indirect Call. */
};

/**
 * Computes the weight of a method parameter
 *
 * @param arg  The parameter whose weight is to be computed.
 */
static unsigned calc_method_param_weight(ir_node *arg)
{
	/* We mark the nodes to avoid endless recursion */
	mark_irn_visited(arg);

	unsigned weight = null_weight;
	foreach_irn_out_r(arg, i, succ) {
		if (irn_visited(succ))
			continue;

		/* We should not walk over the memory edge.*/
		if (get_irn_mode(succ) == mode_M)
			continue;

		switch (get_irn_opcode(succ)) {
		case iro_Call:
			if (get_Call_ptr(succ) == arg) {
				/* the arguments is used as an pointer input for a call,
				   we can probably change an indirect Call into a direct one. */
				weight += indirect_call_weight;
			}
			break;
		case iro_Cmp: {
			/* We have reached a cmp and we must increase the
			   weight with the cmp_weight. */
			ir_node *op;
			if (get_Cmp_left(succ) == arg)
				op = get_Cmp_right(succ);
			else
				op = get_Cmp_left(succ);

			if (is_irn_constlike(op)) {
				weight += const_cmp_weight;
			} else
				weight += cmp_weight;
			break;
		}
		case iro_Cond:
			/* the argument is used for a SwitchCond, a big win */
			weight += const_cmp_weight * get_irn_n_outs(succ);
			break;
		case iro_Id:
			/* when looking backward we might find Id nodes */
			weight += calc_method_param_weight(succ);
			break;
		case iro_Tuple:
			/* unoptimized tuple */
			for (unsigned j = get_Tuple_n_preds(succ); j-- > 0; ) {
				ir_node *pred = get_Tuple_pred(succ, j);
				if (pred == arg) {
					/* look for Proj(j) */
					foreach_irn_out_r(succ, k, succ_succ) {
						if (get_Proj_num(succ_succ) == j) {
							/* found */
							weight += calc_method_param_weight(succ_succ);
						}
					}
				}
			}
			break;
		default:
			if (is_binop(succ)) {
				/* We have reached a BinOp and we must increase the
				   weight with the binop_weight. If the other operand of the
				   BinOp is a constant we increase the weight with const_binop_weight
				   and call the function recursive.
				 */
				ir_node *op;
				if (get_binop_left(succ) == arg)
					op = get_binop_right(succ);
				else
					op = get_binop_left(succ);

				if (is_irn_constlike(op)) {
					weight += const_binop_weight;
					weight += calc_method_param_weight(succ);
				} else
					weight += binop_weight;
			} else if (get_irn_arity(succ) == 1) {
				/* We have reached a binop and we must increase the
				   weight with the const_binop_weight and call the function
				   recursive.*/
				weight += const_binop_weight;
				weight += calc_method_param_weight(succ);
			}
			break;
		}
	}
	return weight;
}

/**
 * Calculate a weight for each argument of an entity.
 *
 * @param ent  The entity of the ir_graph.
 */
static void analyze_method_params_weight(ir_entity *ent)
{
	/* allocate a new array. currently used as 'analysed' flag */
	ir_type *mtp      = get_entity_type(ent);
	size_t   nparams  = get_method_n_params(mtp);
	ent->attr.mtd_attr.param_weight = NEW_ARR_F(unsigned, nparams);

	/* If the method has no parameters, we have nothing to do */
	if (nparams <= 0)
	  return;

	/* First we initialize the parameter weights with 0. */
	for (size_t i = nparams; i-- > 0; )
		ent->attr.mtd_attr.param_weight[i] = null_weight;

	ir_graph *irg = get_entity_irg(ent);
	if (irg == NULL) {
		/* no graph, no better info */
		return;
	}

	/* Call algorithm that computes the out edges */
	assure_irg_outs(irg);

	ir_node *irg_args = get_irg_args(irg);
	foreach_irn_out_r(irg_args, i, arg) {
		unsigned const proj_nr = get_Proj_num(arg);
		ent->attr.mtd_attr.param_weight[proj_nr] += calc_method_param_weight(arg);
	}
}

unsigned get_method_param_weight(ir_entity *ent, size_t pos)
{
	if (!ent->attr.mtd_attr.param_weight)
		analyze_method_params_weight(ent);

	if (pos < ARR_LEN(ent->attr.mtd_attr.param_weight))
		return ent->attr.mtd_attr.param_weight[pos];
	else
		return null_weight;
}

void analyze_irg_args_weight(ir_graph *irg)
{
	ir_entity *entity = get_irg_entity(irg);
	if (entity == NULL)
		return;

	assert(is_method_entity(entity));
	if (entity->attr.mtd_attr.param_weight != NULL)
		return;

	ir_reserve_resources(irg, IR_RESOURCE_IRN_VISITED);
	inc_irg_visited(irg);
	analyze_method_params_weight(entity);
	ir_free_resources(irg, IR_RESOURCE_IRN_VISITED);
}