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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 
32 struct mark_used_data {
33 	unsigned char * const_used;
34 	unsigned * has_rel_addr;
35 };
36 
remap_regs(void * userdata,struct rc_instruction * inst,rc_register_file * pfile,unsigned int * pindex)37 static 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 
mark_used(void * userdata,struct rc_instruction * inst,struct rc_src_register * src)47 static 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 
rc_remove_unused_constants(struct radeon_compiler * c,void * user)61 void 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