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      1 /*
      2  * Copyright  2017 Red Hat
      3  *
      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:
     10  *
     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
     13  * Software.
     14  *
     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
     21  * IN THE SOFTWARE.
     22  *
     23  * Authors:
     24  *    Rob Clark <robclark (at) freedesktop.org>
     25  */
     26 
     27 #include "nir.h"
     28 #include "nir_builder.h"
     29 
     30 #if defined(_WIN32) && !defined(snprintf)
     31 #define snprintf _snprintf
     32 #endif
     33 
     34 /*
     35  * Remap atomic counters to SSBOs.  Atomic counters get remapped to
     36  * SSBO binding points [0..ssbo_offset) and the original SSBOs are
     37  * remapped to [ssbo_offset..n) (mostly to align with what mesa/st
     38  * does.
     39  */
     40 
     41 static bool
     42 lower_instr(nir_intrinsic_instr *instr, unsigned ssbo_offset, nir_builder *b)
     43 {
     44    nir_intrinsic_op op;
     45    int idx_src;
     46 
     47    b->cursor = nir_before_instr(&instr->instr);
     48 
     49    switch (instr->intrinsic) {
     50    case nir_intrinsic_ssbo_atomic_add:
     51    case nir_intrinsic_ssbo_atomic_imin:
     52    case nir_intrinsic_ssbo_atomic_umin:
     53    case nir_intrinsic_ssbo_atomic_imax:
     54    case nir_intrinsic_ssbo_atomic_umax:
     55    case nir_intrinsic_ssbo_atomic_and:
     56    case nir_intrinsic_ssbo_atomic_or:
     57    case nir_intrinsic_ssbo_atomic_xor:
     58    case nir_intrinsic_ssbo_atomic_exchange:
     59    case nir_intrinsic_ssbo_atomic_comp_swap:
     60    case nir_intrinsic_store_ssbo:
     61    case nir_intrinsic_load_ssbo:
     62    case nir_intrinsic_get_buffer_size:
     63       /* easy case, keep same opcode and just remap SSBO buffer index: */
     64       op = instr->intrinsic;
     65       idx_src = (op == nir_intrinsic_store_ssbo) ? 1 : 0;
     66       nir_ssa_def *old_idx = nir_ssa_for_src(b, instr->src[idx_src], 1);
     67       nir_ssa_def *new_idx = nir_iadd(b, old_idx, nir_imm_int(b, ssbo_offset));
     68       nir_instr_rewrite_src(&instr->instr,
     69                             &instr->src[idx_src],
     70                             nir_src_for_ssa(new_idx));
     71       return true;
     72    case nir_intrinsic_atomic_counter_inc:
     73    case nir_intrinsic_atomic_counter_add:
     74    case nir_intrinsic_atomic_counter_dec:
     75       /* inc and dec get remapped to add: */
     76       op = nir_intrinsic_ssbo_atomic_add;
     77       break;
     78    case nir_intrinsic_atomic_counter_read:
     79       op = nir_intrinsic_load_ssbo;
     80       break;
     81    case nir_intrinsic_atomic_counter_min:
     82       op = nir_intrinsic_ssbo_atomic_umin;
     83       break;
     84    case nir_intrinsic_atomic_counter_max:
     85       op = nir_intrinsic_ssbo_atomic_umax;
     86       break;
     87    case nir_intrinsic_atomic_counter_and:
     88       op = nir_intrinsic_ssbo_atomic_and;
     89       break;
     90    case nir_intrinsic_atomic_counter_or:
     91       op = nir_intrinsic_ssbo_atomic_or;
     92       break;
     93    case nir_intrinsic_atomic_counter_xor:
     94       op = nir_intrinsic_ssbo_atomic_xor;
     95       break;
     96    case nir_intrinsic_atomic_counter_exchange:
     97       op = nir_intrinsic_ssbo_atomic_exchange;
     98       break;
     99    case nir_intrinsic_atomic_counter_comp_swap:
    100       op = nir_intrinsic_ssbo_atomic_comp_swap;
    101       break;
    102    default:
    103       return false;
    104    }
    105 
    106    nir_ssa_def *buffer = nir_imm_int(b, nir_intrinsic_base(instr));
    107    nir_ssa_def *temp = NULL;
    108    nir_intrinsic_instr *new_instr =
    109          nir_intrinsic_instr_create(ralloc_parent(instr), op);
    110 
    111    /* a couple instructions need special handling since they don't map
    112     * 1:1 with ssbo atomics
    113     */
    114    switch (instr->intrinsic) {
    115    case nir_intrinsic_atomic_counter_inc:
    116       /* remapped to ssbo_atomic_add: { buffer_idx, offset, +1 } */
    117       temp = nir_imm_int(b, +1);
    118       new_instr->src[0] = nir_src_for_ssa(buffer);
    119       nir_src_copy(&new_instr->src[1], &instr->src[0], new_instr);
    120       new_instr->src[2] = nir_src_for_ssa(temp);
    121       break;
    122    case nir_intrinsic_atomic_counter_dec:
    123       /* remapped to ssbo_atomic_add: { buffer_idx, offset, -1 } */
    124       /* NOTE semantic difference so we adjust the return value below */
    125       temp = nir_imm_int(b, -1);
    126       new_instr->src[0] = nir_src_for_ssa(buffer);
    127       nir_src_copy(&new_instr->src[1], &instr->src[0], new_instr);
    128       new_instr->src[2] = nir_src_for_ssa(temp);
    129       break;
    130    case nir_intrinsic_atomic_counter_read:
    131       /* remapped to load_ssbo: { buffer_idx, offset } */
    132       new_instr->src[0] = nir_src_for_ssa(buffer);
    133       nir_src_copy(&new_instr->src[1], &instr->src[0], new_instr);
    134       break;
    135    default:
    136       /* remapped to ssbo_atomic_x: { buffer_idx, offset, data, (compare)? } */
    137       new_instr->src[0] = nir_src_for_ssa(buffer);
    138       nir_src_copy(&new_instr->src[1], &instr->src[0], new_instr);
    139       nir_src_copy(&new_instr->src[2], &instr->src[1], new_instr);
    140       if (op == nir_intrinsic_ssbo_atomic_comp_swap)
    141          nir_src_copy(&new_instr->src[3], &instr->src[2], new_instr);
    142       break;
    143    }
    144 
    145    nir_ssa_dest_init(&new_instr->instr, &new_instr->dest,
    146                      instr->dest.ssa.num_components,
    147                      instr->dest.ssa.bit_size, NULL);
    148    nir_instr_insert_before(&instr->instr, &new_instr->instr);
    149    nir_instr_remove(&instr->instr);
    150 
    151    if (instr->intrinsic == nir_intrinsic_atomic_counter_dec) {
    152       b->cursor = nir_after_instr(&new_instr->instr);
    153       nir_ssa_def *result = nir_iadd(b, &new_instr->dest.ssa, temp);
    154       nir_ssa_def_rewrite_uses(&instr->dest.ssa, nir_src_for_ssa(result));
    155    } else {
    156       nir_ssa_def_rewrite_uses(&instr->dest.ssa, nir_src_for_ssa(&new_instr->dest.ssa));
    157    }
    158 
    159    /* we could be replacing an intrinsic with fixed # of dest num_components
    160     * with one that has variable number.  So best to take this from the dest:
    161     */
    162    new_instr->num_components = instr->dest.ssa.num_components;
    163 
    164    return true;
    165 }
    166 
    167 static bool
    168 is_atomic_uint(const struct glsl_type *type)
    169 {
    170    if (glsl_get_base_type(type) == GLSL_TYPE_ARRAY)
    171       return is_atomic_uint(glsl_get_array_element(type));
    172    return glsl_get_base_type(type) == GLSL_TYPE_ATOMIC_UINT;
    173 }
    174 
    175 bool
    176 nir_lower_atomics_to_ssbo(nir_shader *shader, unsigned ssbo_offset)
    177 {
    178    bool progress = false;
    179 
    180    nir_foreach_function(function, shader) {
    181       if (function->impl) {
    182          nir_builder builder;
    183          nir_builder_init(&builder, function->impl);
    184          nir_foreach_block(block, function->impl) {
    185             nir_foreach_instr_safe(instr, block) {
    186                if (instr->type == nir_instr_type_intrinsic)
    187                   progress |= lower_instr(nir_instr_as_intrinsic(instr),
    188                                           ssbo_offset, &builder);
    189             }
    190          }
    191 
    192          nir_metadata_preserve(function->impl, nir_metadata_block_index |
    193                                                nir_metadata_dominance);
    194       }
    195    }
    196 
    197    if (progress) {
    198       /* replace atomic_uint uniforms with ssbo's: */
    199       unsigned replaced = 0;
    200       nir_foreach_variable_safe(var, &shader->uniforms) {
    201          if (is_atomic_uint(var->type)) {
    202             exec_node_remove(&var->node);
    203 
    204             if (replaced & (1 << var->data.binding))
    205                continue;
    206 
    207             nir_variable *ssbo;
    208             char name[16];
    209 
    210             /* A length of 0 is used to denote unsized arrays */
    211             const struct glsl_type *type = glsl_array_type(glsl_uint_type(), 0);
    212 
    213             snprintf(name, sizeof(name), "counter%d", var->data.binding);
    214 
    215             ssbo = nir_variable_create(shader, nir_var_shader_storage,
    216                                        type, name);
    217             ssbo->data.binding = var->data.binding;
    218 
    219             struct glsl_struct_field field = {
    220                   .type = type,
    221                   .name = "counters",
    222                   .location = -1,
    223             };
    224 
    225             ssbo->interface_type =
    226                   glsl_interface_type(&field, 1, GLSL_INTERFACE_PACKING_STD430,
    227                                       false, "counters");
    228 
    229             replaced |= (1 << var->data.binding);
    230          }
    231       }
    232    }
    233 
    234    return progress;
    235 }
    236 
    237