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1 /*
2  * Copyright 2020 Advanced Micro Devices, Inc.
3  * All Rights Reserved.
4  *
5  * Permission is hereby granted, free of charge, to any person obtaining a
6  * copy of this software and associated documentation files (the "Software"),
7  * to deal in the Software without restriction, including without limitation
8  * on the rights to use, copy, modify, merge, publish, distribute, sub
9  * license, and/or sell copies of the Software, and to permit persons to whom
10  * the Software is furnished to do so, subject to the following conditions:
11  *
12  * The above copyright notice and this permission notice (including the next
13  * paragraph) shall be included in all copies or substantial portions of the
14  * Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
19  * THE AUTHOR(S) AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM,
20  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
21  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
22  * USE OR OTHER DEALINGS IN THE SOFTWARE.
23  */
24 
25 #include "si_pipe.h"
26 #include "si_shader_internal.h"
27 #include "sid.h"
28 
29 /**
30  * Return a value that is equal to the given i32 \p index if it lies in [0,num)
31  * or an undefined value in the same interval otherwise.
32  */
si_llvm_bound_index(struct si_shader_context * ctx,LLVMValueRef index,unsigned num)33 static LLVMValueRef si_llvm_bound_index(struct si_shader_context *ctx, LLVMValueRef index,
34                                         unsigned num)
35 {
36    LLVMBuilderRef builder = ctx->ac.builder;
37    LLVMValueRef c_max = LLVMConstInt(ctx->ac.i32, num - 1, 0);
38    LLVMValueRef cc;
39 
40    if (util_is_power_of_two_or_zero(num)) {
41       index = LLVMBuildAnd(builder, index, c_max, "");
42    } else {
43       /* In theory, this MAX pattern should result in code that is
44        * as good as the bit-wise AND above.
45        *
46        * In practice, LLVM generates worse code (at the time of
47        * writing), because its value tracking is not strong enough.
48        */
49       cc = LLVMBuildICmp(builder, LLVMIntULE, index, c_max, "");
50       index = LLVMBuildSelect(builder, cc, index, c_max, "");
51    }
52 
53    return index;
54 }
55 
load_const_buffer_desc_fast_path(struct si_shader_context * ctx)56 static LLVMValueRef load_const_buffer_desc_fast_path(struct si_shader_context *ctx)
57 {
58    LLVMValueRef ptr = ac_get_arg(&ctx->ac, ctx->const_and_shader_buffers);
59    struct si_shader_selector *sel = ctx->shader->selector;
60 
61    /* Do the bounds checking with a descriptor, because
62     * doing computation and manual bounds checking of 64-bit
63     * addresses generates horrible VALU code with very high
64     * VGPR usage and very low SIMD occupancy.
65     */
66    ptr = LLVMBuildPtrToInt(ctx->ac.builder, ptr, ctx->ac.intptr, "");
67 
68    LLVMValueRef desc0, desc1;
69    desc0 = ptr;
70    desc1 = LLVMConstInt(ctx->ac.i32, S_008F04_BASE_ADDRESS_HI(ctx->screen->info.address32_hi), 0);
71 
72    uint32_t rsrc3 = S_008F0C_DST_SEL_X(V_008F0C_SQ_SEL_X) | S_008F0C_DST_SEL_Y(V_008F0C_SQ_SEL_Y) |
73                     S_008F0C_DST_SEL_Z(V_008F0C_SQ_SEL_Z) | S_008F0C_DST_SEL_W(V_008F0C_SQ_SEL_W);
74 
75    if (ctx->screen->info.chip_class >= GFX10)
76       rsrc3 |= S_008F0C_FORMAT(V_008F0C_IMG_FORMAT_32_FLOAT) |
77                S_008F0C_OOB_SELECT(V_008F0C_OOB_SELECT_RAW) | S_008F0C_RESOURCE_LEVEL(1);
78    else
79       rsrc3 |= S_008F0C_NUM_FORMAT(V_008F0C_BUF_NUM_FORMAT_FLOAT) |
80                S_008F0C_DATA_FORMAT(V_008F0C_BUF_DATA_FORMAT_32);
81 
82    LLVMValueRef desc_elems[] = {desc0, desc1,
83                                 LLVMConstInt(ctx->ac.i32, sel->info.constbuf0_num_slots * 16, 0),
84                                 LLVMConstInt(ctx->ac.i32, rsrc3, false)};
85 
86    return ac_build_gather_values(&ctx->ac, desc_elems, 4);
87 }
88 
load_ubo(struct ac_shader_abi * abi,unsigned desc_set,unsigned binding,bool valid_binding,LLVMValueRef index)89 static LLVMValueRef load_ubo(struct ac_shader_abi *abi,
90                              unsigned desc_set, unsigned binding,
91                              bool valid_binding, LLVMValueRef index)
92 {
93    struct si_shader_context *ctx = si_shader_context_from_abi(abi);
94    struct si_shader_selector *sel = ctx->shader->selector;
95 
96    LLVMValueRef ptr = ac_get_arg(&ctx->ac, ctx->const_and_shader_buffers);
97 
98    if (sel->info.base.num_ubos == 1 && sel->info.base.num_ssbos == 0) {
99       return load_const_buffer_desc_fast_path(ctx);
100    }
101 
102    index = si_llvm_bound_index(ctx, index, ctx->num_const_buffers);
103    index =
104       LLVMBuildAdd(ctx->ac.builder, index, LLVMConstInt(ctx->ac.i32, SI_NUM_SHADER_BUFFERS, 0), "");
105 
106    return ac_build_load_to_sgpr(&ctx->ac, ptr, index);
107 }
108 
load_ssbo(struct ac_shader_abi * abi,LLVMValueRef index,bool write)109 static LLVMValueRef load_ssbo(struct ac_shader_abi *abi, LLVMValueRef index, bool write)
110 {
111    struct si_shader_context *ctx = si_shader_context_from_abi(abi);
112 
113    /* Fast path if the shader buffer is in user SGPRs. */
114    if (LLVMIsConstant(index) &&
115        LLVMConstIntGetZExtValue(index) < ctx->shader->selector->cs_num_shaderbufs_in_user_sgprs)
116       return ac_get_arg(&ctx->ac, ctx->cs_shaderbuf[LLVMConstIntGetZExtValue(index)]);
117 
118    LLVMValueRef rsrc_ptr = ac_get_arg(&ctx->ac, ctx->const_and_shader_buffers);
119 
120    index = si_llvm_bound_index(ctx, index, ctx->num_shader_buffers);
121    index = LLVMBuildSub(ctx->ac.builder, LLVMConstInt(ctx->ac.i32, SI_NUM_SHADER_BUFFERS - 1, 0),
122                         index, "");
123 
124    return ac_build_load_to_sgpr(&ctx->ac, rsrc_ptr, index);
125 }
126 
127 /**
128  * Given a 256-bit resource descriptor, force the DCC enable bit to off.
129  *
130  * At least on Tonga, executing image stores on images with DCC enabled and
131  * non-trivial can eventually lead to lockups. This can occur when an
132  * application binds an image as read-only but then uses a shader that writes
133  * to it. The OpenGL spec allows almost arbitrarily bad behavior (including
134  * program termination) in this case, but it doesn't cost much to be a bit
135  * nicer: disabling DCC in the shader still leads to undefined results but
136  * avoids the lockup.
137  */
force_dcc_off(struct si_shader_context * ctx,LLVMValueRef rsrc)138 static LLVMValueRef force_dcc_off(struct si_shader_context *ctx, LLVMValueRef rsrc)
139 {
140    if (ctx->screen->info.chip_class <= GFX7) {
141       return rsrc;
142    } else {
143       LLVMValueRef i32_6 = LLVMConstInt(ctx->ac.i32, 6, 0);
144       LLVMValueRef i32_C = LLVMConstInt(ctx->ac.i32, C_008F28_COMPRESSION_EN, 0);
145       LLVMValueRef tmp;
146 
147       tmp = LLVMBuildExtractElement(ctx->ac.builder, rsrc, i32_6, "");
148       tmp = LLVMBuildAnd(ctx->ac.builder, tmp, i32_C, "");
149       return LLVMBuildInsertElement(ctx->ac.builder, rsrc, tmp, i32_6, "");
150    }
151 }
152 
153 /* AC_DESC_FMASK is handled exactly like AC_DESC_IMAGE. The caller should
154  * adjust "index" to point to FMASK. */
si_load_image_desc(struct si_shader_context * ctx,LLVMValueRef list,LLVMValueRef index,enum ac_descriptor_type desc_type,bool uses_store,bool bindless)155 static LLVMValueRef si_load_image_desc(struct si_shader_context *ctx, LLVMValueRef list,
156                                        LLVMValueRef index, enum ac_descriptor_type desc_type,
157                                        bool uses_store, bool bindless)
158 {
159    LLVMBuilderRef builder = ctx->ac.builder;
160    LLVMValueRef rsrc;
161 
162    if (desc_type == AC_DESC_BUFFER) {
163       index = ac_build_imad(&ctx->ac, index, LLVMConstInt(ctx->ac.i32, 2, 0), ctx->ac.i32_1);
164       list = LLVMBuildPointerCast(builder, list, ac_array_in_const32_addr_space(ctx->ac.v4i32), "");
165    } else {
166       assert(desc_type == AC_DESC_IMAGE || desc_type == AC_DESC_FMASK);
167    }
168 
169    if (bindless)
170       rsrc = ac_build_load_to_sgpr_uint_wraparound(&ctx->ac, list, index);
171    else
172       rsrc = ac_build_load_to_sgpr(&ctx->ac, list, index);
173 
174    if (desc_type == AC_DESC_IMAGE && uses_store)
175       rsrc = force_dcc_off(ctx, rsrc);
176    return rsrc;
177 }
178 
179 /**
180  * Load an image view, fmask view. or sampler state descriptor.
181  */
si_load_sampler_desc(struct si_shader_context * ctx,LLVMValueRef list,LLVMValueRef index,enum ac_descriptor_type type)182 static LLVMValueRef si_load_sampler_desc(struct si_shader_context *ctx, LLVMValueRef list,
183                                          LLVMValueRef index, enum ac_descriptor_type type)
184 {
185    LLVMBuilderRef builder = ctx->ac.builder;
186 
187    switch (type) {
188    case AC_DESC_IMAGE:
189       /* The image is at [0:7]. */
190       index = LLVMBuildMul(builder, index, LLVMConstInt(ctx->ac.i32, 2, 0), "");
191       break;
192    case AC_DESC_BUFFER:
193       /* The buffer is in [4:7]. */
194       index = ac_build_imad(&ctx->ac, index, LLVMConstInt(ctx->ac.i32, 4, 0), ctx->ac.i32_1);
195       list = LLVMBuildPointerCast(builder, list, ac_array_in_const32_addr_space(ctx->ac.v4i32), "");
196       break;
197    case AC_DESC_FMASK:
198       /* The FMASK is at [8:15]. */
199       index = ac_build_imad(&ctx->ac, index, LLVMConstInt(ctx->ac.i32, 2, 0), ctx->ac.i32_1);
200       break;
201    case AC_DESC_SAMPLER:
202       /* The sampler state is at [12:15]. */
203       index = ac_build_imad(&ctx->ac, index, LLVMConstInt(ctx->ac.i32, 4, 0),
204                             LLVMConstInt(ctx->ac.i32, 3, 0));
205       list = LLVMBuildPointerCast(builder, list, ac_array_in_const32_addr_space(ctx->ac.v4i32), "");
206       break;
207    case AC_DESC_PLANE_0:
208    case AC_DESC_PLANE_1:
209    case AC_DESC_PLANE_2:
210       /* Only used for the multiplane image support for Vulkan. Should
211        * never be reached in radeonsi.
212        */
213       unreachable("Plane descriptor requested in radeonsi.");
214    }
215 
216    return ac_build_load_to_sgpr(&ctx->ac, list, index);
217 }
218 
si_nir_load_sampler_desc(struct ac_shader_abi * abi,unsigned descriptor_set,unsigned base_index,unsigned constant_index,LLVMValueRef dynamic_index,enum ac_descriptor_type desc_type,bool image,bool write,bool bindless)219 static LLVMValueRef si_nir_load_sampler_desc(struct ac_shader_abi *abi, unsigned descriptor_set,
220                                              unsigned base_index, unsigned constant_index,
221                                              LLVMValueRef dynamic_index,
222                                              enum ac_descriptor_type desc_type, bool image,
223                                              bool write, bool bindless)
224 {
225    struct si_shader_context *ctx = si_shader_context_from_abi(abi);
226    LLVMBuilderRef builder = ctx->ac.builder;
227    unsigned const_index = base_index + constant_index;
228 
229    assert(!descriptor_set);
230    assert(desc_type <= AC_DESC_BUFFER);
231 
232    if (bindless) {
233       LLVMValueRef list = ac_get_arg(&ctx->ac, ctx->bindless_samplers_and_images);
234 
235       /* dynamic_index is the bindless handle */
236       if (image) {
237          /* Bindless image descriptors use 16-dword slots. */
238          dynamic_index =
239             LLVMBuildMul(ctx->ac.builder, dynamic_index, LLVMConstInt(ctx->ac.i64, 2, 0), "");
240          /* FMASK is right after the image. */
241          if (desc_type == AC_DESC_FMASK) {
242             dynamic_index = LLVMBuildAdd(ctx->ac.builder, dynamic_index, ctx->ac.i32_1, "");
243          }
244 
245          return si_load_image_desc(ctx, list, dynamic_index, desc_type, write, true);
246       }
247 
248       /* Since bindless handle arithmetic can contain an unsigned integer
249        * wraparound and si_load_sampler_desc assumes there isn't any,
250        * use GEP without "inbounds" (inside ac_build_pointer_add)
251        * to prevent incorrect code generation and hangs.
252        */
253       dynamic_index =
254          LLVMBuildMul(ctx->ac.builder, dynamic_index, LLVMConstInt(ctx->ac.i64, 2, 0), "");
255       list = ac_build_pointer_add(&ctx->ac, list, dynamic_index);
256       return si_load_sampler_desc(ctx, list, ctx->ac.i32_0, desc_type);
257    }
258 
259    unsigned num_slots = image ? ctx->num_images : ctx->num_samplers;
260    assert(const_index < num_slots || dynamic_index);
261 
262    LLVMValueRef list = ac_get_arg(&ctx->ac, ctx->samplers_and_images);
263    LLVMValueRef index = LLVMConstInt(ctx->ac.i32, const_index, false);
264 
265    if (dynamic_index) {
266       index = LLVMBuildAdd(builder, index, dynamic_index, "");
267 
268       /* From the GL_ARB_shader_image_load_store extension spec:
269        *
270        *    If a shader performs an image load, store, or atomic
271        *    operation using an image variable declared as an array,
272        *    and if the index used to select an individual element is
273        *    negative or greater than or equal to the size of the
274        *    array, the results of the operation are undefined but may
275        *    not lead to termination.
276        */
277       index = si_llvm_bound_index(ctx, index, num_slots);
278    }
279 
280    if (image) {
281       /* Fast path if the image is in user SGPRs. */
282       if (!dynamic_index &&
283           const_index < ctx->shader->selector->cs_num_images_in_user_sgprs &&
284           (desc_type == AC_DESC_IMAGE || desc_type == AC_DESC_BUFFER))
285          return ac_get_arg(&ctx->ac, ctx->cs_image[const_index]);
286 
287       /* FMASKs are separate from images. */
288       if (desc_type == AC_DESC_FMASK) {
289          index =
290             LLVMBuildAdd(ctx->ac.builder, index, LLVMConstInt(ctx->ac.i32, SI_NUM_IMAGES, 0), "");
291       }
292       index = LLVMBuildSub(ctx->ac.builder, LLVMConstInt(ctx->ac.i32, SI_NUM_IMAGE_SLOTS - 1, 0),
293                            index, "");
294       return si_load_image_desc(ctx, list, index, desc_type, write, false);
295    }
296 
297    index = LLVMBuildAdd(ctx->ac.builder, index,
298                         LLVMConstInt(ctx->ac.i32, SI_NUM_IMAGE_SLOTS / 2, 0), "");
299    return si_load_sampler_desc(ctx, list, index, desc_type);
300 }
301 
si_llvm_init_resource_callbacks(struct si_shader_context * ctx)302 void si_llvm_init_resource_callbacks(struct si_shader_context *ctx)
303 {
304    ctx->abi.load_ubo = load_ubo;
305    ctx->abi.load_ssbo = load_ssbo;
306    ctx->abi.load_sampler_desc = si_nir_load_sampler_desc;
307 }
308