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
  47 using namespace ir_builder;
  48
  49 namespace {
  50
  51 class lower_cs_derived_visitor : public ir_hierarchical_visitor {
  52 public:
  53    explicit lower_cs_derived_visitor(gl_linked_shader *shader)
  54       : progress(false),
  55         shader(shader),
  56         local_size_variable(shader->Program->info.cs.local_size_variable),
  57         gl_WorkGroupSize(NULL),
  58         gl_WorkGroupID(NULL),
  59         gl_LocalInvocationID(NULL),
  60         gl_GlobalInvocationID(NULL),
  61         gl_LocalInvocationIndex(NULL)
  62    {
  63       main_sig = _mesa_get_main_function_signature(shader->symbols);
  64       assert(main_sig);
  65    }
  66
  67    virtual ir_visitor_status visit(ir_dereference_variable *);
  68
  69    ir_variable *add_system_value(
  70          int slot, const glsl_type *type, const char *name);
  71    void find_sysvals();
  72    void make_gl_GlobalInvocationID();
  73    void make_gl_LocalInvocationIndex();
  74
  75    bool progress;
  76
  77 private:
  78    gl_linked_shader *shader;
  79    bool local_size_variable;
  80    ir_function_signature *main_sig;
  81
  82    ir_rvalue *gl_WorkGroupSize;
  83    ir_variable *gl_WorkGroupID;
  84    ir_variable *gl_LocalInvocationID;
  85
  86    ir_variable *gl_GlobalInvocationID;
  87    ir_variable *gl_LocalInvocationIndex;
  88 };
  89
  90 } /* anonymous namespace */
  91
  92 ir_variable *
  93 lower_cs_derived_visitor::add_system_value(
  94       int slot, const glsl_type *type, const char *name)
  95 {
  96    ir_variable *var = new(shader) ir_variable(type, name, ir_var_system_value);
  97    var->data.how_declared = ir_var_declared_implicitly;
  98    var->data.read_only = true;
  99    var->data.location = slot;
 100    var->data.explicit_location = true;
 101    var->data.explicit_index = 0;
 102    shader->ir->push_head(var);
 103
 104    return var;
 105 }
 106
 107 void
 108 lower_cs_derived_visitor::find_sysvals()
 109 {
 110    if (gl_WorkGroupSize != NULL)
 111       return;
 112
 113    ir_variable *WorkGroupSize;
 114    if (local_size_variable)
 115       WorkGroupSize = shader->symbols->get_variable("gl_LocalGroupSizeARB");
 116    else
 117       WorkGroupSize = shader->symbols->get_variable("gl_WorkGroupSize");
 118    if (WorkGroupSize)
 119       gl_WorkGroupSize = new(shader) ir_dereference_variable(WorkGroupSize);
 120    gl_WorkGroupID = shader->symbols->get_variable("gl_WorkGroupID");
 121    gl_LocalInvocationID = shader->symbols->get_variable("gl_LocalInvocationID");
 122
 123    /*
 124     * These may be missing due to either dead code elimination, or, in the
 125     * case of the group size, due to the layout being declared in a non-main
 126     * shader. Re-create them.
 127     */
 128
 129    if (!gl_WorkGroupID)
 130       gl_WorkGroupID = add_system_value(
 131             SYSTEM_VALUE_WORK_GROUP_ID, glsl_type::uvec3_type, "gl_WorkGroupID");
 132    if (!gl_LocalInvocationID)
 133       gl_LocalInvocationID = add_system_value(
 134             SYSTEM_VALUE_LOCAL_INVOCATION_ID, glsl_type::uvec3_type,
 135             "gl_LocalInvocationID");
 136    if (!WorkGroupSize) {
 137       if (local_size_variable) {
 138          gl_WorkGroupSize = new(shader) ir_dereference_variable(
 139                add_system_value(
 140                      SYSTEM_VALUE_LOCAL_GROUP_SIZE, glsl_type::uvec3_type,
 141                      "gl_LocalGroupSizeARB"));
 142       } else {
 143          ir_constant_data data;
 144          memset(&data, 0, sizeof(data));
 145          for (int i = 0; i < 3; i++)
 146             data.u[i] = shader->Program->info.cs.local_size[i];
 147          gl_WorkGroupSize = new(shader) ir_constant(glsl_type::uvec3_type, &data);
 148       }
 149    }
 150 }
 151
 152 void
 153 lower_cs_derived_visitor::make_gl_GlobalInvocationID()
 154 {
 155    if (gl_GlobalInvocationID != NULL)
 156       return;
 157
 158    find_sysvals();
 159
 160    /* gl_GlobalInvocationID =
 161     *    gl_WorkGroupID * gl_WorkGroupSize + gl_LocalInvocationID
 162     */
 163    gl_GlobalInvocationID = new(shader) ir_variable(
 164          glsl_type::uvec3_type, "__GlobalInvocationID", ir_var_temporary);
 165    shader->ir->push_head(gl_GlobalInvocationID);
 166
 167    ir_instruction *inst =
 168       assign(gl_GlobalInvocationID,
 169              add(mul(gl_WorkGroupID, gl_WorkGroupSize->clone(shader, NULL)),
 170                  gl_LocalInvocationID));
 171    main_sig->body.push_head(inst);
 172 }
 173
 174 void
 175 lower_cs_derived_visitor::make_gl_LocalInvocationIndex()
 176 {
 177    if (gl_LocalInvocationIndex != NULL)
 178       return;
 179
 180    find_sysvals();
 181
 182    /* gl_LocalInvocationIndex =
 183     *    gl_LocalInvocationID.z * gl_WorkGroupSize.x * gl_WorkGroupSize.y +
 184     *    gl_LocalInvocationID.y * gl_WorkGroupSize.x +
 185     *    gl_LocalInvocationID.x;
 186     */
 187    gl_LocalInvocationIndex = new(shader)
 188       ir_variable(glsl_type::uint_type, "__LocalInvocationIndex", ir_var_temporary);
 189    shader->ir->push_head(gl_LocalInvocationIndex);
 190
 191    ir_expression *index_z =
 192       mul(mul(swizzle_z(gl_LocalInvocationID), swizzle_x(gl_WorkGroupSize->clone(shader, NULL))),
 193           swizzle_y(gl_WorkGroupSize->clone(shader, NULL)));
 194    ir_expression *index_y =
 195       mul(swizzle_y(gl_LocalInvocationID), swizzle_x(gl_WorkGroupSize->clone(shader, NULL)));
 196    ir_expression *index_y_plus_z = add(index_y, index_z);
 197    operand index_x(swizzle_x(gl_LocalInvocationID));
 198    ir_expression *index_x_plus_y_plus_z = add(index_y_plus_z, index_x);
 199    ir_instruction *inst =
 200       assign(gl_LocalInvocationIndex, index_x_plus_y_plus_z);
 201    main_sig->body.push_head(inst);
 202 }
 203
 204 ir_visitor_status
 205 lower_cs_derived_visitor::visit(ir_dereference_variable *ir)
 206 {
 207    if (ir->var->data.mode == ir_var_system_value &&
 208        ir->var->data.location == SYSTEM_VALUE_GLOBAL_INVOCATION_ID) {
 209       make_gl_GlobalInvocationID();
 210       ir->var = gl_GlobalInvocationID;
 211       progress = true;
 212    }
 213
 214    if (ir->var->data.mode == ir_var_system_value &&
 215        ir->var->data.location == SYSTEM_VALUE_LOCAL_INVOCATION_INDEX) {
 216       make_gl_LocalInvocationIndex();
 217       ir->var = gl_LocalInvocationIndex;
 218       progress = true;
 219    }
 220
 221    return visit_continue;
 222 }
 223
 224 bool
 225 lower_cs_derived(gl_linked_shader *shader)
 226 {
 227    if (shader->Stage != MESA_SHADER_COMPUTE)
 228       return false;
 229
 230    lower_cs_derived_visitor v(shader);
 231    v.run(shader->ir);
 232
 233    return v.progress;
 234 }