2 * Copyright © 2018 Intel Corporation
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
25 #include "nir_builder.h"
26 #include "nir_deref.h"
35 /* Block that has all the variable stores. All the blocks with reads
36 * should be dominated by this block.
40 /* If is_constant, hold the collected constant data for this var. */
41 uint32_t constant_data_size
;
46 var_info_cmp(const void *_a
, const void *_b
)
48 const struct var_info
*a
= _a
;
49 const struct var_info
*b
= _b
;
50 uint32_t a_size
= a
->constant_data_size
;
51 uint32_t b_size
= b
->constant_data_size
;
53 if (a_size
< b_size
) {
55 } else if (a_size
> b_size
) {
57 } else if (a_size
== 0) {
58 /* Don't call memcmp with invalid pointers. */
61 return memcmp(a
->constant_data
, b
->constant_data
, a_size
);
66 build_constant_load(nir_builder
*b
, nir_deref_instr
*deref
,
67 glsl_type_size_align_func size_align
)
69 nir_variable
*var
= nir_deref_instr_get_variable(deref
);
71 const unsigned bit_size
= glsl_get_bit_size(deref
->type
);
72 const unsigned num_components
= glsl_get_vector_elements(deref
->type
);
74 UNUSED
unsigned var_size
, var_align
;
75 size_align(var
->type
, &var_size
, &var_align
);
76 assert(var
->data
.location
% var_align
== 0);
78 nir_intrinsic_instr
*load
=
79 nir_intrinsic_instr_create(b
->shader
, nir_intrinsic_load_constant
);
80 load
->num_components
= num_components
;
81 nir_intrinsic_set_base(load
, var
->data
.location
);
82 nir_intrinsic_set_range(load
, var_size
);
83 load
->src
[0] = nir_src_for_ssa(nir_build_deref_offset(b
, deref
, size_align
));
84 nir_ssa_dest_init(&load
->instr
, &load
->dest
,
85 num_components
, bit_size
, NULL
);
86 nir_builder_instr_insert(b
, &load
->instr
);
88 if (load
->dest
.ssa
.bit_size
< 8) {
89 /* Booleans are special-cased to be 32-bit
91 * Ideally, for drivers that can handle 32-bit booleans, we wouldn't
92 * emit the i2b here. However, at this point, the driver is likely to
93 * still have 1-bit booleans so we need to at least convert bit sizes.
94 * Unfortunately, we don't have a good way to annotate the load as
95 * loading a known boolean value so the optimizer isn't going to be
96 * able to get rid of the conversion. Some day, we may solve that
97 * problem but not today.
99 assert(glsl_type_is_boolean(deref
->type
));
100 load
->dest
.ssa
.bit_size
= 32;
101 return nir_i2b(b
, &load
->dest
.ssa
);
103 return &load
->dest
.ssa
;
108 handle_constant_store(void *mem_ctx
, struct var_info
*info
,
109 nir_deref_instr
*deref
, nir_const_value
*val
,
111 glsl_type_size_align_func size_align
)
113 assert(!nir_deref_instr_has_indirect(deref
));
114 const unsigned bit_size
= glsl_get_bit_size(deref
->type
);
115 const unsigned num_components
= glsl_get_vector_elements(deref
->type
);
117 if (info
->constant_data_size
== 0) {
118 unsigned var_size
, var_align
;
119 size_align(info
->var
->type
, &var_size
, &var_align
);
120 info
->constant_data_size
= var_size
;
121 info
->constant_data
= rzalloc_size(mem_ctx
, var_size
);
124 char *dst
= (char *)info
->constant_data
+
125 nir_deref_instr_get_const_offset(deref
, size_align
);
127 for (unsigned i
= 0; i
< num_components
; i
++) {
128 if (!(writemask
& (1 << i
)))
133 /* Booleans are special-cased to be 32-bit */
134 ((int32_t *)dst
)[i
] = -(int)val
[i
].b
;
138 ((uint8_t *)dst
)[i
] = val
[i
].u8
;
142 ((uint16_t *)dst
)[i
] = val
[i
].u16
;
146 ((uint32_t *)dst
)[i
] = val
[i
].u32
;
150 ((uint64_t *)dst
)[i
] = val
[i
].u64
;
154 unreachable("Invalid bit size");
159 /** Lower large constant variables to shader constant data
161 * This pass looks for large (type_size(var->type) > threshold) variables
162 * which are statically constant and moves them into shader constant data.
163 * This is especially useful when large tables are baked into the shader
164 * source code because they can be moved into a UBO by the driver to reduce
165 * register pressure and make indirect access cheaper.
168 nir_opt_large_constants(nir_shader
*shader
,
169 glsl_type_size_align_func size_align
,
172 /* Default to a natural alignment if none is provided */
173 if (size_align
== NULL
)
174 size_align
= glsl_get_natural_size_align_bytes
;
176 /* This only works with a single entrypoint */
177 nir_function_impl
*impl
= nir_shader_get_entrypoint(shader
);
179 /* This pass can only be run once */
180 assert(shader
->constant_data
== NULL
&& shader
->constant_data_size
== 0);
182 unsigned num_locals
= exec_list_length(&impl
->locals
);
183 nir_index_vars(shader
, impl
, nir_var_function_temp
);
188 struct var_info
*var_infos
= ralloc_array(NULL
, struct var_info
, num_locals
);
189 nir_foreach_variable(var
, &impl
->locals
) {
190 var_infos
[var
->index
] = (struct var_info
) {
197 nir_metadata_require(impl
, nir_metadata_dominance
);
199 /* First, walk through the shader and figure out what variables we can
200 * lower to the constant blob.
202 nir_foreach_block(block
, impl
) {
203 nir_foreach_instr(instr
, block
) {
204 if (instr
->type
!= nir_instr_type_intrinsic
)
207 nir_intrinsic_instr
*intrin
= nir_instr_as_intrinsic(instr
);
209 bool src_is_const
= false;
210 nir_deref_instr
*src_deref
= NULL
, *dst_deref
= NULL
;
211 unsigned writemask
= 0;
212 switch (intrin
->intrinsic
) {
213 case nir_intrinsic_store_deref
:
214 dst_deref
= nir_src_as_deref(intrin
->src
[0]);
215 src_is_const
= nir_src_is_const(intrin
->src
[1]);
216 writemask
= nir_intrinsic_write_mask(intrin
);
219 case nir_intrinsic_load_deref
:
220 src_deref
= nir_src_as_deref(intrin
->src
[0]);
223 case nir_intrinsic_copy_deref
:
224 assert(!"Lowering of copy_deref with large constants is prohibited");
231 if (dst_deref
&& dst_deref
->mode
== nir_var_function_temp
) {
232 nir_variable
*var
= nir_deref_instr_get_variable(dst_deref
);
233 assert(var
->data
.mode
== nir_var_function_temp
);
235 struct var_info
*info
= &var_infos
[var
->index
];
236 if (!info
->is_constant
)
242 /* We only consider variables constant if they only have constant
243 * stores, all the stores come before any reads, and all stores
244 * come from the same block. We also can't handle indirect stores.
246 if (!src_is_const
|| info
->found_read
|| block
!= info
->block
||
247 nir_deref_instr_has_indirect(dst_deref
)) {
248 info
->is_constant
= false;
250 nir_const_value
*val
= nir_src_as_const_value(intrin
->src
[1]);
251 handle_constant_store(var_infos
, info
, dst_deref
, val
, writemask
,
256 if (src_deref
&& src_deref
->mode
== nir_var_function_temp
) {
257 nir_variable
*var
= nir_deref_instr_get_variable(src_deref
);
258 assert(var
->data
.mode
== nir_var_function_temp
);
260 /* We only consider variables constant if all the reads are
261 * dominated by the block that writes to it.
263 struct var_info
*info
= &var_infos
[var
->index
];
264 if (!info
->is_constant
)
267 if (!info
->block
|| !nir_block_dominates(info
->block
, block
))
268 info
->is_constant
= false;
270 info
->found_read
= true;
275 /* Allocate constant data space for each variable that just has constant
276 * data. We sort them by size and content so we can easily find
279 shader
->constant_data_size
= 0;
280 qsort(var_infos
, num_locals
, sizeof(struct var_info
), var_info_cmp
);
281 for (int i
= 0; i
< num_locals
; i
++) {
282 struct var_info
*info
= &var_infos
[i
];
284 /* Fix up indices after we sorted. */
285 info
->var
->index
= i
;
287 if (!info
->is_constant
)
290 unsigned var_size
, var_align
;
291 size_align(info
->var
->type
, &var_size
, &var_align
);
292 if (var_size
<= threshold
|| !info
->found_read
) {
293 /* Don't bother lowering small stuff or data that's never read */
294 info
->is_constant
= false;
298 if (i
> 0 && var_info_cmp(info
, &var_infos
[i
- 1]) == 0) {
299 info
->var
->data
.location
= var_infos
[i
- 1].var
->data
.location
;
300 info
->duplicate
= true;
302 info
->var
->data
.location
= ALIGN_POT(shader
->constant_data_size
, var_align
);
303 shader
->constant_data_size
= info
->var
->data
.location
+ var_size
;
307 if (shader
->constant_data_size
== 0) {
308 ralloc_free(var_infos
);
312 shader
->constant_data
= rzalloc_size(shader
, shader
->constant_data_size
);
313 for (int i
= 0; i
< num_locals
; i
++) {
314 struct var_info
*info
= &var_infos
[i
];
315 if (!info
->duplicate
&& info
->is_constant
) {
316 memcpy((char *)shader
->constant_data
+ info
->var
->data
.location
,
317 info
->constant_data
, info
->constant_data_size
);
322 nir_builder_init(&b
, impl
);
324 nir_foreach_block(block
, impl
) {
325 nir_foreach_instr_safe(instr
, block
) {
326 if (instr
->type
!= nir_instr_type_intrinsic
)
329 nir_intrinsic_instr
*intrin
= nir_instr_as_intrinsic(instr
);
331 switch (intrin
->intrinsic
) {
332 case nir_intrinsic_load_deref
: {
333 nir_deref_instr
*deref
= nir_src_as_deref(intrin
->src
[0]);
334 if (deref
->mode
!= nir_var_function_temp
)
337 nir_variable
*var
= nir_deref_instr_get_variable(deref
);
338 struct var_info
*info
= &var_infos
[var
->index
];
339 if (info
->is_constant
) {
340 b
.cursor
= nir_after_instr(&intrin
->instr
);
341 nir_ssa_def
*val
= build_constant_load(&b
, deref
, size_align
);
342 nir_ssa_def_rewrite_uses(&intrin
->dest
.ssa
,
343 nir_src_for_ssa(val
));
344 nir_instr_remove(&intrin
->instr
);
345 nir_deref_instr_remove_if_unused(deref
);
350 case nir_intrinsic_store_deref
: {
351 nir_deref_instr
*deref
= nir_src_as_deref(intrin
->src
[0]);
352 if (deref
->mode
!= nir_var_function_temp
)
355 nir_variable
*var
= nir_deref_instr_get_variable(deref
);
356 struct var_info
*info
= &var_infos
[var
->index
];
357 if (info
->is_constant
) {
358 nir_instr_remove(&intrin
->instr
);
359 nir_deref_instr_remove_if_unused(deref
);
363 case nir_intrinsic_copy_deref
:
370 /* Clean up the now unused variables */
371 for (int i
= 0; i
< num_locals
; i
++) {
372 struct var_info
*info
= &var_infos
[i
];
373 if (info
->is_constant
)
374 exec_node_remove(&info
->var
->node
);
377 ralloc_free(var_infos
);
379 nir_metadata_preserve(impl
, nir_metadata_block_index
|
380 nir_metadata_dominance
);