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