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 class flatten_named_interface_blocks_declarations : public ir_rvalue_visitor
  69 {
  70 public:
  71    void * const mem_ctx;
  72    hash_table *interface_namespace;
  73
  74    flatten_named_interface_blocks_declarations(void *mem_ctx)
  75       : mem_ctx(mem_ctx)
  76    {
  77    }
  78
  79    void run(exec_list *instructions);
  80
  81    virtual ir_visitor_status visit_leave(ir_assignment *);
  82    virtual void handle_rvalue(ir_rvalue **rvalue);
  83 };
  84
  85 void
  86 flatten_named_interface_blocks_declarations::run(exec_list *instructions)
  87 {
  88    interface_namespace = hash_table_ctor(0, hash_table_string_hash,
  89                                          hash_table_string_compare);
  90
  91    /* First pass: adjust instance block variables with an instance name
  92     * to not have an instance name.
  93     *
  94     * The interface block variables are stored in the interface_namespace
  95     * hash table so they can be used in the second pass.
  96     */
  97    foreach_list_safe(node, instructions) {
  98       ir_variable *var = ((ir_instruction *) node)->as_variable();
  99       if (!var || !var->is_interface_instance())
 100          continue;
 101
 102       /* It should be possible to handle uniforms during this pass,
 103        * but, this will require changes to the other uniform block
 104        * support code.
 105        */
 106       if (var->mode == ir_var_uniform)
 107          continue;
 108
 109       const glsl_type * iface_t = var->type;
 110       const glsl_type * array_t = NULL;
 111       exec_node *insert_pos = var;
 112
 113       if (iface_t->is_array()) {
 114          array_t = iface_t;
 115          iface_t = array_t->fields.array;
 116       }
 117
 118       assert (iface_t->is_interface());
 119
 120       for (unsigned i = 0; i < iface_t->length; i++) {
 121          const char * field_name = iface_t->fields.structure[i].name;
 122          char *iface_field_name =
 123             ralloc_asprintf(mem_ctx, "%s.%s",
 124                             iface_t->name, field_name);
 125
 126          ir_variable *found_var =
 127             (ir_variable *) hash_table_find(interface_namespace,
 128                                             iface_field_name);
 129          if (!found_var) {
 130             ir_variable *new_var;
 131             if (array_t == NULL) {
 132                char *var_name =
 133                   ralloc_strdup(mem_ctx, iface_t->fields.structure[i].name);
 134                new_var =
 135                   new(mem_ctx) ir_variable(iface_t->fields.structure[i].type,
 136                                            var_name,
 137                                            (ir_variable_mode) var->mode);
 138             } else {
 139                const glsl_type *new_array_type =
 140                   glsl_type::get_array_instance(
 141                      iface_t->fields.structure[i].type,
 142                      array_t->length);
 143                char *var_name =
 144                   ralloc_asprintf(mem_ctx, "%s[%d]",
 145                                   iface_t->fields.structure[i].name,
 146                                   array_t->length);
 147                new_var =
 148                   new(mem_ctx) ir_variable(new_array_type,
 149                                            var_name,
 150                                            (ir_variable_mode) var->mode);
 151             }
 152
 153             new_var->interface_type = iface_t;
 154             hash_table_insert(interface_namespace, new_var,
 155                               iface_field_name);
 156             insert_pos->insert_after(new_var);
 157             insert_pos = new_var;
 158          }
 159       }
 160       var->remove();
 161    }
 162
 163    /* Second pass: visit all ir_dereference_record instances, and if they
 164     * reference an interface block, then flatten the refererence out.
 165     */
 166    visit_list_elements(this, instructions);
 167    hash_table_dtor(interface_namespace);
 168    interface_namespace = NULL;
 169 }
 170
 171 ir_visitor_status
 172 flatten_named_interface_blocks_declarations::visit_leave(ir_assignment *ir)
 173 {
 174    ir_dereference_record *lhs_rec = ir->lhs->as_dereference_record();
 175    if (lhs_rec) {
 176       ir_rvalue *lhs_rec_tmp = lhs_rec;
 177       handle_rvalue(&lhs_rec_tmp);
 178       if (lhs_rec_tmp != lhs_rec) {
 179          ir->set_lhs(lhs_rec_tmp);
 180       }
 181    }
 182    return rvalue_visit(ir);
 183 }
 184
 185 void
 186 flatten_named_interface_blocks_declarations::handle_rvalue(ir_rvalue **rvalue)
 187 {
 188    if (*rvalue == NULL)
 189       return;
 190
 191    ir_dereference_record *ir = (*rvalue)->as_dereference_record();
 192    if (ir == NULL)
 193       return;
 194
 195    ir_variable *var = ir->variable_referenced();
 196
 197    if (!var->is_interface_instance())
 198       return;
 199
 200    /* It should be possible to handle uniforms during this pass,
 201     * but, this will require changes to the other uniform block
 202     * support code.
 203     */
 204    if (var->mode == ir_var_uniform)
 205       return;
 206
 207    if (var->interface_type != NULL) {
 208       char *iface_field_name =
 209          ralloc_asprintf(mem_ctx, "%s.%s", var->interface_type->name,
 210                          ir->field);
 211       /* Find the variable in the set of flattened interface blocks */
 212       ir_variable *found_var =
 213          (ir_variable *) hash_table_find(interface_namespace,
 214                                          iface_field_name);
 215       assert(found_var);
 216
 217       ir_dereference_variable *deref_var =
 218          new(mem_ctx) ir_dereference_variable(found_var);
 219
 220       ir_dereference_array *deref_array =
 221          ir->record->as_dereference_array();
 222       if (deref_array != NULL) {
 223          *rvalue =
 224             new(mem_ctx) ir_dereference_array(deref_var,
 225                                               deref_array->array_index);
 226       } else {
 227          *rvalue = deref_var;
 228       }
 229    }
 230 }
 231
 232 void
 233 lower_named_interface_blocks(void *mem_ctx, gl_shader *shader)
 234 {
 235    flatten_named_interface_blocks_declarations v_decl(mem_ctx);
 236    v_decl.run(shader->ir);
 237 }
 238