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 #include "svga_debug.h"
  29
  30 #include "tgsi/tgsi_strings.h"
  31
  32
  33 #define INVALID_INDEX 255
  34
  35
  36 /**
  37  * Examine input and output shaders info to link outputs from the
  38  * output shader to inputs from the input shader.
  39  * Basically, we'll remap input shader's input slots to new numbers
  40  * based on semantic name/index of the outputs from the output shader.
  41  */
  42 void
  43 svga_link_shaders(const struct tgsi_shader_info *outshader_info,
  44                   const struct tgsi_shader_info *inshader_info,
  45                   struct shader_linkage *linkage)
  46 {
  47    unsigned i, free_slot;
  48
  49    for (i = 0; i < ARRAY_SIZE(linkage->input_map); i++) {
  50       linkage->input_map[i] = INVALID_INDEX;
  51    }
  52
  53    /* Assign input slots for input shader inputs.
  54     * Basically, we want to use the same index for the output shader's outputs
  55     * and the input shader's inputs that should be linked together.
  56     * We'll modify the input shader's inputs to match the output shader.
  57     */
  58    assert(inshader_info->num_inputs <=
  59           ARRAY_SIZE(inshader_info->input_semantic_name));
  60
  61    /* free register index that can be used for built-in varyings */
  62    free_slot = outshader_info->num_outputs + 1;
  63
  64    for (i = 0; i < inshader_info->num_inputs; i++) {
  65       enum tgsi_semantic sem_name = inshader_info->input_semantic_name[i];
  66       unsigned sem_index = inshader_info->input_semantic_index[i];
  67       unsigned j;
  68       /**
  69        * Get the clip distance inputs from the output shader's
  70        * clip distance shadow copy.
  71        */
  72       if (sem_name == TGSI_SEMANTIC_CLIPDIST) {
  73          linkage->input_map[i] = outshader_info->num_outputs + 1 + sem_index;
  74          /* make sure free_slot includes this extra output */
  75          free_slot = MAX2(free_slot, linkage->input_map[i] + 1);
  76       }
  77       else {
  78          /* search output shader outputs for same item */
  79          for (j = 0; j < outshader_info->num_outputs; j++) {
  80             assert(j < ARRAY_SIZE(outshader_info->output_semantic_name));
  81             if (outshader_info->output_semantic_name[j] == sem_name &&
  82                 outshader_info->output_semantic_index[j] == sem_index) {
  83                linkage->input_map[i] = j;
  84                break;
  85             }
  86          }
  87       }
  88    }
  89
  90    linkage->num_inputs = inshader_info->num_inputs;
  91
  92    /* Things like the front-face register are handled here */
  93    for (i = 0; i < inshader_info->num_inputs; i++) {
  94       if (linkage->input_map[i] == INVALID_INDEX) {
  95          unsigned j = free_slot++;
  96          linkage->input_map[i] = j;
  97       }
  98    }
  99
 100    /* Debug */
 101    if (SVGA_DEBUG & DEBUG_TGSI) {
 102       unsigned reg = 0;
 103       debug_printf("### linkage info:\n");
 104
 105       for (i = 0; i < linkage->num_inputs; i++) {
 106
 107          assert(linkage->input_map[i] != INVALID_INDEX);
 108
 109          debug_printf("   input[%d] slot %u  %s %u %s\n",
 110                       i,
 111                       linkage->input_map[i],
 112                       tgsi_semantic_names[inshader_info->input_semantic_name[i]],
 113                       inshader_info->input_semantic_index[i],
 114                       tgsi_interpolate_names[inshader_info->input_interpolate[i]]);
 115
 116          /* make sure no repeating register index */
 117          if (reg & 1 << linkage->input_map[i]) {
 118             assert(0);
 119          }
 120          reg |= 1 << linkage->input_map[i];
 121       }
 122    }
 123 }