src/gallium/drivers/svga/svga_link.c

   1 /*/
   2  * Copyright 2013 VMware, Inc.  All rights reserved.
   3  *
   4  * Permission is hereby granted, free of charge, to any person
   5  * obtaining a copy of this software and associated documentation
   6  * files (the "Software"), to deal in the Software without
   7  * restriction, including without limitation the rights to use, copy,
   8  * modify, merge, publish, distribute, sublicense, and/or sell copies
   9  * of the Software, and to permit persons to whom the Software is
  10  * furnished to do so, subject to the following conditions:
  11  *
  12  * The above copyright notice and this permission notice shall be
  13  * included in all copies or substantial portions of the Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  16  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  17  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  18  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  19  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  20  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  21  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  22  * SOFTWARE.
  23  */
  24
  25
  26 #include "svga_context.h"
  27 #include "svga_link.h"
  28
  29 #include "tgsi/tgsi_strings.h"
  30
  31
  32 #define INVALID_INDEX 255
  33
  34
  35 /**
  36  * Examine input and output shaders info to link outputs from the
  37  * output shader to inputs from the input shader.
  38  * Basically, we'll remap input shader's input slots to new numbers
  39  * based on semantic name/index of the outputs from the output shader.
  40  */
  41 void
  42 svga_link_shaders(const struct tgsi_shader_info *outshader_info,
  43                   const struct tgsi_shader_info *inshader_info,
  44                   struct shader_linkage *linkage)
  45 {
  46    unsigned i, free_slot;
  47
  48    for (i = 0; i < ARRAY_SIZE(linkage->input_map); i++) {
  49       linkage->input_map[i] = INVALID_INDEX;
  50    }
  51
  52    /* Assign input slots for input shader inputs.
  53     * Basically, we want to use the same index for the output shader's outputs
  54     * and the input shader's inputs that should be linked together.
  55     * We'll modify the input shader's inputs to match the output shader.
  56     */
  57    assert(inshader_info->num_inputs <=
  58           ARRAY_SIZE(inshader_info->input_semantic_name));
  59
  60    /* free register index that can be used for built-in varyings */
  61    free_slot = outshader_info->num_outputs + 1;
  62
  63    for (i = 0; i < inshader_info->num_inputs; i++) {
  64       unsigned sem_name = inshader_info->input_semantic_name[i];
  65       unsigned sem_index = inshader_info->input_semantic_index[i];
  66       unsigned j;
  67       /**
  68        * Get the clip distance inputs from the output shader's
  69        * clip distance shadow copy.
  70        */
  71       if (sem_name == TGSI_SEMANTIC_CLIPDIST) {
  72          linkage->input_map[i] = outshader_info->num_outputs + 1 + sem_index;
  73          /* make sure free_slot includes this extra output */
  74          free_slot = MAX2(free_slot, linkage->input_map[i] + 1);
  75       }
  76       else {
  77          /* search output shader outputs for same item */
  78          for (j = 0; j < outshader_info->num_outputs; j++) {
  79             assert(j < ARRAY_SIZE(outshader_info->output_semantic_name));
  80             if (outshader_info->output_semantic_name[j] == sem_name &&
  81                 outshader_info->output_semantic_index[j] == sem_index) {
  82                linkage->input_map[i] = j;
  83                break;
  84             }
  85          }
  86       }
  87    }
  88
  89    linkage->num_inputs = inshader_info->num_inputs;
  90
  91    /* Things like the front-face register are handled here */
  92    for (i = 0; i < inshader_info->num_inputs; i++) {
  93       if (linkage->input_map[i] == INVALID_INDEX) {
  94          unsigned j = free_slot++;
  95          linkage->input_map[i] = j;
  96       }
  97    }
  98
  99    /* Debug */
 100    if (0) {
 101       unsigned reg = 0;
 102       for (i = 0; i < linkage->num_inputs; i++) {
 103
 104          assert(linkage->input_map[i] != INVALID_INDEX);
 105
 106          debug_printf("input shader input[%d] slot %u  %s %u %s\n",
 107                       i,
 108                       linkage->input_map[i],
 109                       tgsi_semantic_names[inshader_info->input_semantic_name[i]],
 110                       inshader_info->input_semantic_index[i],
 111                       tgsi_interpolate_names[inshader_info->input_interpolate[i]]);
 112
 113          /* make sure no repeating register index */
 114          if (reg & 1 << linkage->input_map[i]) {
 115             assert(0);
 116          }
 117          reg |= 1 << linkage->input_map[i];
 118       }
 119    }
 120 }