src/glsl/link_atomics.cpp

   1 /*
   2  * Copyright © 2013 Intel Corporation
   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
  21  * DEALINGS IN THE SOFTWARE.
  22  */
  23
  24 #include "glsl_parser_extras.h"
  25 #include "ir.h"
  26 #include "ir_uniform.h"
  27 #include "linker.h"
  28 #include "program/hash_table.h"
  29 #include "main/macros.h"
  30
  31 namespace {
  32    /*
  33     * Atomic counter as seen by the program.
  34     */
  35    struct active_atomic_counter {
  36       unsigned uniform_loc;
  37       ir_variable *var;
  38    };
  39
  40    /*
  41     * Atomic counter buffer referenced by the program.  There is a one
  42     * to one correspondence between these and the objects that can be
  43     * queried using glGetActiveAtomicCounterBufferiv().
  44     */
  45    struct active_atomic_buffer {
  46       active_atomic_buffer()
  47          : counters(0), num_counters(0), stage_references(), size(0)
  48       {}
  49
  50       ~active_atomic_buffer()
  51       {
  52          free(counters);
  53       }
  54
  55       void push_back(unsigned uniform_loc, ir_variable *var)
  56       {
  57          active_atomic_counter *new_counters;
  58
  59          new_counters = (active_atomic_counter *)
  60             realloc(counters, sizeof(active_atomic_counter) *
  61                     (num_counters + 1));
  62
  63          if (new_counters == NULL) {
  64             _mesa_error_no_memory(__func__);
  65             return;
  66          }
  67
  68          counters = new_counters;
  69          counters[num_counters].uniform_loc = uniform_loc;
  70          counters[num_counters].var = var;
  71          num_counters++;
  72       }
  73
  74       active_atomic_counter *counters;
  75       unsigned num_counters;
  76       unsigned stage_references[MESA_SHADER_STAGES];
  77       unsigned size;
  78    };
  79
  80    int
  81    cmp_actives(const void *a, const void *b)
  82    {
  83       const active_atomic_counter *const first = (active_atomic_counter *) a;
  84       const active_atomic_counter *const second = (active_atomic_counter *) b;
  85
  86       return int(first->var->data.atomic.offset) - int(second->var->data.atomic.offset);
  87    }
  88
  89    bool
  90    check_atomic_counters_overlap(const ir_variable *x, const ir_variable *y)
  91    {
  92       return ((x->data.atomic.offset >= y->data.atomic.offset &&
  93                x->data.atomic.offset < y->data.atomic.offset + y->type->atomic_size()) ||
  94               (y->data.atomic.offset >= x->data.atomic.offset &&
  95                y->data.atomic.offset < x->data.atomic.offset + x->type->atomic_size()));
  96    }
  97
  98    void
  99    process_atomic_variable(const glsl_type *t, struct gl_shader_program *prog,
 100                            unsigned *uniform_loc, ir_variable *var,
 101                            active_atomic_buffer *const buffers,
 102                            unsigned *num_buffers, int *offset,
 103                            const unsigned shader_stage)
 104    {
 105       /* FIXME: Arrays of arrays get counted separately. For example:
 106        * x1[3][3][2] = 9 counters
 107        * x2[3][2]    = 3 counters
 108        * x3[2]       = 1 counter
 109        *
 110        * However this code marks all the counters as active even when they
 111        * might not be used.
 112        */
 113       if (t->is_array() && t->fields.array->is_array()) {
 114          for (unsigned i = 0; i < t->length; i++) {
 115             process_atomic_variable(t->fields.array, prog, uniform_loc,
 116                                     var, buffers, num_buffers, offset,
 117                                     shader_stage);
 118          }
 119       } else {
 120          active_atomic_buffer *buf = &buffers[var->data.binding];
 121          gl_uniform_storage *const storage =
 122             &prog->UniformStorage[*uniform_loc];
 123
 124          /* If this is the first time the buffer is used, increment
 125           * the counter of buffers used.
 126           */
 127          if (buf->size == 0)
 128             (*num_buffers)++;
 129
 130          buf->push_back(*uniform_loc, var);
 131
 132          buf->stage_references[shader_stage]++;
 133          buf->size = MAX2(buf->size, *offset + t->atomic_size());
 134
 135          storage->offset = *offset;
 136          *offset += t->atomic_size();
 137
 138          (*uniform_loc)++;
 139       }
 140    }
 141
 142    active_atomic_buffer *
 143    find_active_atomic_counters(struct gl_context *ctx,
 144                                struct gl_shader_program *prog,
 145                                unsigned *num_buffers)
 146    {
 147       active_atomic_buffer *const buffers =
 148          new active_atomic_buffer[ctx->Const.MaxAtomicBufferBindings];
 149
 150       *num_buffers = 0;
 151
 152       for (unsigned i = 0; i < MESA_SHADER_STAGES; ++i) {
 153          struct gl_shader *sh = prog->_LinkedShaders[i];
 154          if (sh == NULL)
 155             continue;
 156
 157          foreach_in_list(ir_instruction, node, sh->ir) {
 158             ir_variable *var = node->as_variable();
 159
 160             if (var && var->type->contains_atomic()) {
 161                int offset = var->data.atomic.offset;
 162                unsigned uniform_loc = var->data.location;
 163                process_atomic_variable(var->type, prog, &uniform_loc,
 164                                        var, buffers, num_buffers, &offset, i);
 165             }
 166          }
 167       }
 168
 169       for (unsigned i = 0; i < ctx->Const.MaxAtomicBufferBindings; i++) {
 170          if (buffers[i].size == 0)
 171             continue;
 172
 173          qsort(buffers[i].counters, buffers[i].num_counters,
 174                sizeof(active_atomic_counter),
 175                cmp_actives);
 176
 177          for (unsigned j = 1; j < buffers[i].num_counters; j++) {
 178             /* If an overlapping counter found, it must be a reference to the
 179              * same counter from a different shader stage.
 180              */
 181             if (check_atomic_counters_overlap(buffers[i].counters[j-1].var,
 182                                               buffers[i].counters[j].var)
 183                 && strcmp(buffers[i].counters[j-1].var->name,
 184                           buffers[i].counters[j].var->name) != 0) {
 185                linker_error(prog, "Atomic counter %s declared at offset %d "
 186                             "which is already in use.",
 187                             buffers[i].counters[j].var->name,
 188                             buffers[i].counters[j].var->data.atomic.offset);
 189             }
 190          }
 191       }
 192       return buffers;
 193    }
 194 }
 195
 196 void
 197 link_assign_atomic_counter_resources(struct gl_context *ctx,
 198                                      struct gl_shader_program *prog)
 199 {
 200    unsigned num_buffers;
 201    active_atomic_buffer *abs =
 202       find_active_atomic_counters(ctx, prog, &num_buffers);
 203
 204    prog->AtomicBuffers = rzalloc_array(prog, gl_active_atomic_buffer,
 205                                        num_buffers);
 206    prog->NumAtomicBuffers = num_buffers;
 207
 208    unsigned i = 0;
 209    for (unsigned binding = 0;
 210         binding < ctx->Const.MaxAtomicBufferBindings;
 211         binding++) {
 212
 213       /* If the binding was not used, skip.
 214        */
 215       if (abs[binding].size == 0)
 216          continue;
 217
 218       active_atomic_buffer &ab = abs[binding];
 219       gl_active_atomic_buffer &mab = prog->AtomicBuffers[i];
 220
 221       /* Assign buffer-specific fields. */
 222       mab.Binding = binding;
 223       mab.MinimumSize = ab.size;
 224       mab.Uniforms = rzalloc_array(prog->AtomicBuffers, GLuint,
 225                                    ab.num_counters);
 226       mab.NumUniforms = ab.num_counters;
 227
 228       /* Assign counter-specific fields. */
 229       for (unsigned j = 0; j < ab.num_counters; j++) {
 230          ir_variable *const var = ab.counters[j].var;
 231          gl_uniform_storage *const storage =
 232             &prog->UniformStorage[ab.counters[j].uniform_loc];
 233
 234          mab.Uniforms[j] = ab.counters[j].uniform_loc;
 235          if (!var->data.explicit_binding)
 236             var->data.binding = i;
 237
 238          storage->atomic_buffer_index = i;
 239          storage->offset = var->data.atomic.offset;
 240          storage->array_stride = (var->type->is_array() ?
 241                                   var->type->without_array()->atomic_size() : 0);
 242       }
 243
 244       /* Assign stage-specific fields. */
 245       for (unsigned j = 0; j < MESA_SHADER_STAGES; ++j)
 246          mab.StageReferences[j] =
 247             (ab.stage_references[j] ? GL_TRUE : GL_FALSE);
 248
 249       i++;
 250    }
 251
 252    delete [] abs;
 253    assert(i == num_buffers);
 254 }
 255
 256 void
 257 link_check_atomic_counter_resources(struct gl_context *ctx,
 258                                     struct gl_shader_program *prog)
 259 {
 260    unsigned num_buffers;
 261    active_atomic_buffer *const abs =
 262       find_active_atomic_counters(ctx, prog, &num_buffers);
 263    unsigned atomic_counters[MESA_SHADER_STAGES] = {};
 264    unsigned atomic_buffers[MESA_SHADER_STAGES] = {};
 265    unsigned total_atomic_counters = 0;
 266    unsigned total_atomic_buffers = 0;
 267
 268    /* Sum the required resources.  Note that this counts buffers and
 269     * counters referenced by several shader stages multiple times
 270     * against the combined limit -- That's the behavior the spec
 271     * requires.
 272     */
 273    for (unsigned i = 0; i < ctx->Const.MaxAtomicBufferBindings; i++) {
 274       if (abs[i].size == 0)
 275          continue;
 276
 277       for (unsigned j = 0; j < MESA_SHADER_STAGES; ++j) {
 278          const unsigned n = abs[i].stage_references[j];
 279
 280          if (n) {
 281             atomic_counters[j] += n;
 282             total_atomic_counters += n;
 283             atomic_buffers[j]++;
 284             total_atomic_buffers++;
 285          }
 286       }
 287    }
 288
 289    /* Check that they are within the supported limits. */
 290    for (unsigned i = 0; i < MESA_SHADER_STAGES; i++) {
 291       if (atomic_counters[i] > ctx->Const.Program[i].MaxAtomicCounters)
 292          linker_error(prog, "Too many %s shader atomic counters",
 293                       _mesa_shader_stage_to_string(i));
 294
 295       if (atomic_buffers[i] > ctx->Const.Program[i].MaxAtomicBuffers)
 296          linker_error(prog, "Too many %s shader atomic counter buffers",
 297                       _mesa_shader_stage_to_string(i));
 298    }
 299
 300    if (total_atomic_counters > ctx->Const.MaxCombinedAtomicCounters)
 301       linker_error(prog, "Too many combined atomic counters");
 302
 303    if (total_atomic_buffers > ctx->Const.MaxCombinedAtomicBuffers)
 304       linker_error(prog, "Too many combined atomic buffers");
 305
 306    delete [] abs;
 307 }