src/compiler/glsl/lower_cs_derived.cpp

   1 /*
   2  * Copyright © 2017 Ilia Mirkin
   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 /**
  25  * \file lower_cs_derived.cpp
  26  *
  27  * For hardware that does not support the gl_GlobalInvocationID and
  28  * gl_LocalInvocationIndex system values, replace them with fresh
  29  * globals. Note that we can't rely on gl_WorkGroupSize or
  30  * gl_LocalGroupSizeARB being available, since they may only have been defined
  31  * in a non-main shader.
  32  *
  33  * [ This can happen if only a secondary shader has the layout(local_size_*)
  34  *   declaration. ]
  35  *
  36  * This is meant to be run post-linking.
  37  */
  38
  39 #include "glsl_symbol_table.h"
  40 #include "ir_hierarchical_visitor.h"
  41 #include "ir.h"
  42 #include "ir_builder.h"
  43 #include "linker.h"
  44 #include "program/prog_statevars.h"
  45 #include "builtin_functions.h"
  46 #include "main/mtypes.h"
  47
  48 using namespace ir_builder;
  49
  50 namespace {
  51
  52 class lower_cs_derived_visitor : public ir_hierarchical_visitor {
  53 public:
  54    explicit lower_cs_derived_visitor(gl_linked_shader *shader)
  55       : progress(false),
  56         shader(shader),
  57         local_size_variable(shader->Program->info.cs.local_size_variable),
  58         gl_WorkGroupSize(NULL),
  59         gl_WorkGroupID(NULL),
  60         gl_LocalInvocationID(NULL),
  61         gl_GlobalInvocationID(NULL),
  62         gl_LocalInvocationIndex(NULL)
  63    {
  64       main_sig = _mesa_get_main_function_signature(shader->symbols);
  65       assert(main_sig);
  66    }
  67
  68    virtual ir_visitor_status visit(ir_dereference_variable *);
  69
  70    ir_variable *add_system_value(
  71          int slot, const glsl_type *type, const char *name);
  72    void find_sysvals();
  73    void make_gl_GlobalInvocationID();
  74    void make_gl_LocalInvocationIndex();
  75
  76    bool progress;
  77
  78 private:
  79    gl_linked_shader *shader;
  80    bool local_size_variable;
  81    ir_function_signature *main_sig;
  82
  83    ir_rvalue *gl_WorkGroupSize;
  84    ir_variable *gl_WorkGroupID;
  85    ir_variable *gl_LocalInvocationID;
  86
  87    ir_variable *gl_GlobalInvocationID;
  88    ir_variable *gl_LocalInvocationIndex;
  89 };
  90
  91 } /* anonymous namespace */
  92
  93 ir_variable *
  94 lower_cs_derived_visitor::add_system_value(
  95       int slot, const glsl_type *type, const char *name)
  96 {
  97    ir_variable *var = new(shader) ir_variable(type, name, ir_var_system_value);
  98    var->data.how_declared = ir_var_declared_implicitly;
  99    var->data.read_only = true;
 100    var->data.location = slot;
 101    var->data.explicit_location = true;
 102    var->data.explicit_index = 0;
 103    shader->ir->push_head(var);
 104
 105    return var;
 106 }
 107
 108 void
 109 lower_cs_derived_visitor::find_sysvals()
 110 {
 111    if (gl_WorkGroupSize != NULL)
 112       return;
 113
 114    ir_variable *WorkGroupSize;
 115    if (local_size_variable)
 116       WorkGroupSize = shader->symbols->get_variable("gl_LocalGroupSizeARB");
 117    else
 118       WorkGroupSize = shader->symbols->get_variable("gl_WorkGroupSize");
 119    if (WorkGroupSize)
 120       gl_WorkGroupSize = new(shader) ir_dereference_variable(WorkGroupSize);
 121    gl_WorkGroupID = shader->symbols->get_variable("gl_WorkGroupID");
 122    gl_LocalInvocationID = shader->symbols->get_variable("gl_LocalInvocationID");
 123
 124    /*
 125     * These may be missing due to either dead code elimination, or, in the
 126     * case of the group size, due to the layout being declared in a non-main
 127     * shader. Re-create them.
 128     */
 129
 130    if (!gl_WorkGroupID)
 131       gl_WorkGroupID = add_system_value(
 132             SYSTEM_VALUE_WORK_GROUP_ID, glsl_type::uvec3_type, "gl_WorkGroupID");
 133    if (!gl_LocalInvocationID)
 134       gl_LocalInvocationID = add_system_value(
 135             SYSTEM_VALUE_LOCAL_INVOCATION_ID, glsl_type::uvec3_type,
 136             "gl_LocalInvocationID");
 137    if (!WorkGroupSize) {
 138       if (local_size_variable) {
 139          gl_WorkGroupSize = new(shader) ir_dereference_variable(
 140                add_system_value(
 141                      SYSTEM_VALUE_LOCAL_GROUP_SIZE, glsl_type::uvec3_type,
 142                      "gl_LocalGroupSizeARB"));
 143       } else {
 144          ir_constant_data data;
 145          memset(&data, 0, sizeof(data));
 146          for (int i = 0; i < 3; i++)
 147             data.u[i] = shader->Program->info.cs.local_size[i];
 148          gl_WorkGroupSize = new(shader) ir_constant(glsl_type::uvec3_type, &data);
 149       }
 150    }
 151 }
 152
 153 void
 154 lower_cs_derived_visitor::make_gl_GlobalInvocationID()
 155 {
 156    if (gl_GlobalInvocationID != NULL)
 157       return;
 158
 159    find_sysvals();
 160
 161    /* gl_GlobalInvocationID =
 162     *    gl_WorkGroupID * gl_WorkGroupSize + gl_LocalInvocationID
 163     */
 164    gl_GlobalInvocationID = new(shader) ir_variable(
 165          glsl_type::uvec3_type, "__GlobalInvocationID", ir_var_temporary);
 166    shader->ir->push_head(gl_GlobalInvocationID);
 167
 168    ir_instruction *inst =
 169       assign(gl_GlobalInvocationID,
 170              add(mul(gl_WorkGroupID, gl_WorkGroupSize->clone(shader, NULL)),
 171                  gl_LocalInvocationID));
 172    main_sig->body.push_head(inst);
 173 }
 174
 175 void
 176 lower_cs_derived_visitor::make_gl_LocalInvocationIndex()
 177 {
 178    if (gl_LocalInvocationIndex != NULL)
 179       return;
 180
 181    find_sysvals();
 182
 183    /* gl_LocalInvocationIndex =
 184     *    gl_LocalInvocationID.z * gl_WorkGroupSize.x * gl_WorkGroupSize.y +
 185     *    gl_LocalInvocationID.y * gl_WorkGroupSize.x +
 186     *    gl_LocalInvocationID.x;
 187     */
 188    gl_LocalInvocationIndex = new(shader)
 189       ir_variable(glsl_type::uint_type, "__LocalInvocationIndex", ir_var_temporary);
 190    shader->ir->push_head(gl_LocalInvocationIndex);
 191
 192    ir_expression *index_z =
 193       mul(mul(swizzle_z(gl_LocalInvocationID), swizzle_x(gl_WorkGroupSize->clone(shader, NULL))),
 194           swizzle_y(gl_WorkGroupSize->clone(shader, NULL)));
 195    ir_expression *index_y =
 196       mul(swizzle_y(gl_LocalInvocationID), swizzle_x(gl_WorkGroupSize->clone(shader, NULL)));
 197    ir_expression *index_y_plus_z = add(index_y, index_z);
 198    operand index_x(swizzle_x(gl_LocalInvocationID));
 199    ir_expression *index_x_plus_y_plus_z = add(index_y_plus_z, index_x);
 200    ir_instruction *inst =
 201       assign(gl_LocalInvocationIndex, index_x_plus_y_plus_z);
 202    main_sig->body.push_head(inst);
 203 }
 204
 205 ir_visitor_status
 206 lower_cs_derived_visitor::visit(ir_dereference_variable *ir)
 207 {
 208    if (ir->var->data.mode == ir_var_system_value &&
 209        ir->var->data.location == SYSTEM_VALUE_GLOBAL_INVOCATION_ID) {
 210       make_gl_GlobalInvocationID();
 211       ir->var = gl_GlobalInvocationID;
 212       progress = true;
 213    }
 214
 215    if (ir->var->data.mode == ir_var_system_value &&
 216        ir->var->data.location == SYSTEM_VALUE_LOCAL_INVOCATION_INDEX) {
 217       make_gl_LocalInvocationIndex();
 218       ir->var = gl_LocalInvocationIndex;
 219       progress = true;
 220    }
 221
 222    return visit_continue;
 223 }
 224
 225 bool
 226 lower_cs_derived(gl_linked_shader *shader)
 227 {
 228    if (shader->Stage != MESA_SHADER_COMPUTE)
 229       return false;
 230
 231    lower_cs_derived_visitor v(shader);
 232    v.run(shader->ir);
 233
 234    return v.progress;
 235 }