1/*
2 * Copyright (C) 2010 Marek Olšák <maraeo@gmail.com>
3 *
4 * All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining
7 * a copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sublicense, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
13 *
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial
16 * portions of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
19 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
21 * IN NO EVENT SHALL THE COPYRIGHT OWNER(S) AND/OR ITS SUPPLIERS BE
22 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
23 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
24 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25 *
26 */
27
28#include <stdlib.h>
29#include "radeon_remove_constants.h"
30#include "radeon_dataflow.h"
31
32struct mark_used_data {
33	unsigned char * const_used;
34	unsigned * has_rel_addr;
35};
36
37static void remap_regs(void * userdata, struct rc_instruction * inst,
38			rc_register_file * pfile, unsigned int * pindex)
39{
40	unsigned *inv_remap_table = userdata;
41
42	if (*pfile == RC_FILE_CONSTANT) {
43		*pindex = inv_remap_table[*pindex];
44	}
45}
46
47static void mark_used(void * userdata, struct rc_instruction * inst,
48						struct rc_src_register * src)
49{
50	struct mark_used_data * d = userdata;
51
52	if (src->File == RC_FILE_CONSTANT) {
53		if (src->RelAddr) {
54			*d->has_rel_addr = 1;
55		} else {
56			d->const_used[src->Index] = 1;
57		}
58	}
59}
60
61void rc_remove_unused_constants(struct radeon_compiler *c, void *user)
62{
63	unsigned **out_remap_table = (unsigned**)user;
64	unsigned char *const_used;
65	unsigned *remap_table;
66	unsigned *inv_remap_table;
67	unsigned has_rel_addr = 0;
68	unsigned is_identity = 1;
69	unsigned are_externals_remapped = 0;
70	struct rc_constant *constants = c->Program.Constants.Constants;
71	struct mark_used_data d;
72	unsigned new_count;
73
74	if (!c->Program.Constants.Count) {
75		*out_remap_table = NULL;
76		return;
77	}
78
79	const_used = malloc(c->Program.Constants.Count);
80	memset(const_used, 0, c->Program.Constants.Count);
81
82	d.const_used = const_used;
83	d.has_rel_addr = &has_rel_addr;
84
85	/* Pass 1: Mark used constants. */
86	for (struct rc_instruction *inst = c->Program.Instructions.Next;
87	     inst != &c->Program.Instructions; inst = inst->Next) {
88		rc_for_all_reads_src(inst, mark_used, &d);
89	}
90
91	/* Pass 2: If there is relative addressing or dead constant elimination
92	 * is disabled, mark all externals as used. */
93	if (has_rel_addr || !c->remove_unused_constants) {
94		for (unsigned i = 0; i < c->Program.Constants.Count; i++)
95			if (constants[i].Type == RC_CONSTANT_EXTERNAL)
96				const_used[i] = 1;
97	}
98
99	/* Pass 3: Make the remapping table and remap constants.
100	 * This pass removes unused constants simply by overwriting them by other constants. */
101	remap_table = malloc(c->Program.Constants.Count * sizeof(unsigned));
102	inv_remap_table = malloc(c->Program.Constants.Count * sizeof(unsigned));
103	new_count = 0;
104
105	for (unsigned i = 0; i < c->Program.Constants.Count; i++) {
106		if (const_used[i]) {
107			remap_table[new_count] = i;
108			inv_remap_table[i] = new_count;
109
110			if (i != new_count) {
111				if (constants[i].Type == RC_CONSTANT_EXTERNAL)
112					are_externals_remapped = 1;
113
114				constants[new_count] = constants[i];
115				is_identity = 0;
116			}
117			new_count++;
118		}
119	}
120
121	/*  is_identity ==> new_count == old_count
122	 * !is_identity ==> new_count <  old_count */
123	assert( is_identity || new_count <  c->Program.Constants.Count);
124	assert(!((has_rel_addr || !c->remove_unused_constants) && are_externals_remapped));
125
126	/* Pass 4: Redirect reads of all constants to their new locations. */
127	if (!is_identity) {
128		for (struct rc_instruction *inst = c->Program.Instructions.Next;
129		     inst != &c->Program.Instructions; inst = inst->Next) {
130			rc_remap_registers(inst, remap_regs, inv_remap_table);
131		}
132	}
133
134	/* Set the new constant count. Note that new_count may be less than
135	 * Count even though the remapping function is identity. In that case,
136	 * the constants have been removed at the end of the array. */
137	c->Program.Constants.Count = new_count;
138
139	if (are_externals_remapped) {
140		*out_remap_table = remap_table;
141	} else {
142		*out_remap_table = NULL;
143		free(remap_table);
144	}
145
146	free(const_used);
147	free(inv_remap_table);
148
149	if (c->Debug & RC_DBG_LOG)
150		rc_constants_print(&c->Program.Constants);
151}
152