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 "radeon_remove_constants.h"
29#include "radeon_dataflow.h"
30
31struct mark_used_data {
32	unsigned char * const_used;
33	unsigned * has_rel_addr;
34};
35
36static void remap_regs(void * userdata, struct rc_instruction * inst,
37			rc_register_file * pfile, unsigned int * pindex)
38{
39	unsigned *inv_remap_table = userdata;
40
41	if (*pfile == RC_FILE_CONSTANT) {
42		*pindex = inv_remap_table[*pindex];
43	}
44}
45
46static void mark_used(void * userdata, struct rc_instruction * inst,
47						struct rc_src_register * src)
48{
49	struct mark_used_data * d = userdata;
50
51	if (src->File == RC_FILE_CONSTANT) {
52		if (src->RelAddr) {
53			*d->has_rel_addr = 1;
54		} else {
55			d->const_used[src->Index] = 1;
56		}
57	}
58}
59
60void rc_remove_unused_constants(struct radeon_compiler *c, void *user)
61{
62	unsigned **out_remap_table = (unsigned**)user;
63	unsigned char *const_used;
64	unsigned *remap_table;
65	unsigned *inv_remap_table;
66	unsigned has_rel_addr = 0;
67	unsigned is_identity = 1;
68	unsigned are_externals_remapped = 0;
69	struct rc_constant *constants = c->Program.Constants.Constants;
70	struct mark_used_data d;
71	unsigned new_count;
72
73	if (!c->Program.Constants.Count) {
74		*out_remap_table = NULL;
75		return;
76	}
77
78	const_used = malloc(c->Program.Constants.Count);
79	memset(const_used, 0, c->Program.Constants.Count);
80
81	d.const_used = const_used;
82	d.has_rel_addr = &has_rel_addr;
83
84	/* Pass 1: Mark used constants. */
85	for (struct rc_instruction *inst = c->Program.Instructions.Next;
86	     inst != &c->Program.Instructions; inst = inst->Next) {
87		rc_for_all_reads_src(inst, mark_used, &d);
88	}
89
90	/* Pass 2: If there is relative addressing or dead constant elimination
91	 * is disabled, mark all externals as used. */
92	if (has_rel_addr || !c->remove_unused_constants) {
93		for (unsigned i = 0; i < c->Program.Constants.Count; i++)
94			if (constants[i].Type == RC_CONSTANT_EXTERNAL)
95				const_used[i] = 1;
96	}
97
98	/* Pass 3: Make the remapping table and remap constants.
99	 * This pass removes unused constants simply by overwriting them by other constants. */
100	remap_table = malloc(c->Program.Constants.Count * sizeof(unsigned));
101	inv_remap_table = malloc(c->Program.Constants.Count * sizeof(unsigned));
102	new_count = 0;
103
104	for (unsigned i = 0; i < c->Program.Constants.Count; i++) {
105		if (const_used[i]) {
106			remap_table[new_count] = i;
107			inv_remap_table[i] = new_count;
108
109			if (i != new_count) {
110				if (constants[i].Type == RC_CONSTANT_EXTERNAL)
111					are_externals_remapped = 1;
112
113				constants[new_count] = constants[i];
114				is_identity = 0;
115			}
116			new_count++;
117		}
118	}
119
120	/*  is_identity ==> new_count == old_count
121	 * !is_identity ==> new_count <  old_count */
122	assert( is_identity || new_count <  c->Program.Constants.Count);
123	assert(!((has_rel_addr || !c->remove_unused_constants) && are_externals_remapped));
124
125	/* Pass 4: Redirect reads of all constants to their new locations. */
126	if (!is_identity) {
127		for (struct rc_instruction *inst = c->Program.Instructions.Next;
128		     inst != &c->Program.Instructions; inst = inst->Next) {
129			rc_remap_registers(inst, remap_regs, inv_remap_table);
130		}
131	}
132
133	/* Set the new constant count. Note that new_count may be less than
134	 * Count even though the remapping function is identity. In that case,
135	 * the constants have been removed at the end of the array. */
136	c->Program.Constants.Count = new_count;
137
138	if (are_externals_remapped) {
139		*out_remap_table = remap_table;
140	} else {
141		*out_remap_table = NULL;
142		free(remap_table);
143	}
144
145	free(const_used);
146	free(inv_remap_table);
147
148	if (c->Debug & RC_DBG_LOG)
149		rc_constants_print(&c->Program.Constants);
150}
151