src/glsl/lower_named_interface_blocks.cpp

   1 /*
   2  * Copyright (c) 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 /**
  25  * \file lower_named_interface_blocks.cpp
  26  *
  27  * This lowering pass converts all interface blocks with instance names
  28  * into interface blocks without an instance name.
  29  *
  30  * For example, the following shader:
  31  *
  32  *   out block {
  33  *     float block_var;
  34  *   } inst_name;
  35  *
  36  *   main()
  37  *   {
  38  *     inst_name.block_var = 0.0;
  39  *   }
  40  *
  41  * Is rewritten to:
  42  *
  43  *   out block {
  44  *     float block_var;
  45  *   };
  46  *
  47  *   main()
  48  *   {
  49  *     block_var = 0.0;
  50  *   }
  51  *
  52  * This takes place after the shader code has already been verified with
  53  * the interface name in place.
  54  *
  55  * The linking phase will use the interface block name rather than the
  56  * interface's instance name when linking interfaces.
  57  *
  58  * This modification to the ir allows our currently existing dead code
  59  * elimination to work with interface blocks without changes.
  60  */
  61
  62 #include "glsl_symbol_table.h"
  63 #include "ir.h"
  64 #include "ir_optimization.h"
  65 #include "ir_rvalue_visitor.h"
  66 #include "program/hash_table.h"
  67
  68 namespace {
  69
  70 class flatten_named_interface_blocks_declarations : public ir_rvalue_visitor
  71 {
  72 public:
  73    void * const mem_ctx;
  74    hash_table *interface_namespace;
  75
  76    flatten_named_interface_blocks_declarations(void *mem_ctx)
  77       : mem_ctx(mem_ctx),
  78         interface_namespace(NULL)
  79    {
  80    }
  81
  82    void run(exec_list *instructions);
  83
  84    virtual ir_visitor_status visit_leave(ir_assignment *);
  85    virtual void handle_rvalue(ir_rvalue **rvalue);
  86 };
  87
  88 } /* anonymous namespace */
  89
  90 void
  91 flatten_named_interface_blocks_declarations::run(exec_list *instructions)
  92 {
  93    interface_namespace = hash_table_ctor(0, hash_table_string_hash,
  94                                          hash_table_string_compare);
  95
  96    /* First pass: adjust instance block variables with an instance name
  97     * to not have an instance name.
  98     *
  99     * The interface block variables are stored in the interface_namespace
 100     * hash table so they can be used in the second pass.
 101     */
 102    foreach_list_safe(node, instructions) {
 103       ir_variable *var = ((ir_instruction *) node)->as_variable();
 104       if (!var || !var->is_interface_instance())
 105          continue;
 106
 107       /* It should be possible to handle uniforms during this pass,
 108        * but, this will require changes to the other uniform block
 109        * support code.
 110        */
 111       if (var->mode == ir_var_uniform)
 112          continue;
 113
 114       const glsl_type * iface_t = var->type;
 115       const glsl_type * array_t = NULL;
 116       exec_node *insert_pos = var;
 117
 118       if (iface_t->is_array()) {
 119          array_t = iface_t;
 120          iface_t = array_t->fields.array;
 121       }
 122
 123       assert (iface_t->is_interface());
 124
 125       for (unsigned i = 0; i < iface_t->length; i++) {
 126          const char * field_name = iface_t->fields.structure[i].name;
 127          char *iface_field_name =
 128             ralloc_asprintf(mem_ctx, "%s.%s",
 129                             iface_t->name, field_name);
 130
 131          ir_variable *found_var =
 132             (ir_variable *) hash_table_find(interface_namespace,
 133                                             iface_field_name);
 134          if (!found_var) {
 135             ir_variable *new_var;
 136             char *var_name =
 137                ralloc_strdup(mem_ctx, iface_t->fields.structure[i].name);
 138             if (array_t == NULL) {
 139                new_var =
 140                   new(mem_ctx) ir_variable(iface_t->fields.structure[i].type,
 141                                            var_name,
 142                                            (ir_variable_mode) var->mode);
 143             } else {
 144                const glsl_type *new_array_type =
 145                   glsl_type::get_array_instance(
 146                      iface_t->fields.structure[i].type,
 147                      array_t->length);
 148                new_var =
 149                   new(mem_ctx) ir_variable(new_array_type,
 150                                            var_name,
 151                                            (ir_variable_mode) var->mode);
 152             }
 153             new_var->location = iface_t->fields.structure[i].location;
 154
 155             new_var->interface_type = iface_t;
 156             hash_table_insert(interface_namespace, new_var,
 157                               iface_field_name);
 158             insert_pos->insert_after(new_var);
 159             insert_pos = new_var;
 160          }
 161       }
 162       var->remove();
 163    }
 164
 165    /* Second pass: visit all ir_dereference_record instances, and if they
 166     * reference an interface block, then flatten the refererence out.
 167     */
 168    visit_list_elements(this, instructions);
 169    hash_table_dtor(interface_namespace);
 170    interface_namespace = NULL;
 171 }
 172
 173 ir_visitor_status
 174 flatten_named_interface_blocks_declarations::visit_leave(ir_assignment *ir)
 175 {
 176    ir_dereference_record *lhs_rec = ir->lhs->as_dereference_record();
 177    if (lhs_rec) {
 178       ir_rvalue *lhs_rec_tmp = lhs_rec;
 179       handle_rvalue(&lhs_rec_tmp);
 180       if (lhs_rec_tmp != lhs_rec) {
 181          ir->set_lhs(lhs_rec_tmp);
 182       }
 183    }
 184    return rvalue_visit(ir);
 185 }
 186
 187 void
 188 flatten_named_interface_blocks_declarations::handle_rvalue(ir_rvalue **rvalue)
 189 {
 190    if (*rvalue == NULL)
 191       return;
 192
 193    ir_dereference_record *ir = (*rvalue)->as_dereference_record();
 194    if (ir == NULL)
 195       return;
 196
 197    ir_variable *var = ir->variable_referenced();
 198    if (var == NULL)
 199       return;
 200
 201    if (!var->is_interface_instance())
 202       return;
 203
 204    /* It should be possible to handle uniforms during this pass,
 205     * but, this will require changes to the other uniform block
 206     * support code.
 207     */
 208    if (var->mode == ir_var_uniform)
 209       return;
 210
 211    if (var->interface_type != NULL) {
 212       char *iface_field_name =
 213          ralloc_asprintf(mem_ctx, "%s.%s", var->interface_type->name,
 214                          ir->field);
 215       /* Find the variable in the set of flattened interface blocks */
 216       ir_variable *found_var =
 217          (ir_variable *) hash_table_find(interface_namespace,
 218                                          iface_field_name);
 219       assert(found_var);
 220
 221       ir_dereference_variable *deref_var =
 222          new(mem_ctx) ir_dereference_variable(found_var);
 223
 224       ir_dereference_array *deref_array =
 225          ir->record->as_dereference_array();
 226       if (deref_array != NULL) {
 227          *rvalue =
 228             new(mem_ctx) ir_dereference_array(deref_var,
 229                                               deref_array->array_index);
 230       } else {
 231          *rvalue = deref_var;
 232       }
 233    }
 234 }
 235
 236 void
 237 lower_named_interface_blocks(void *mem_ctx, gl_shader *shader)
 238 {
 239    flatten_named_interface_blocks_declarations v_decl(mem_ctx);
 240    v_decl.run(shader->ir);
 241 }
 242