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    for (i = 0; i < ARRAY_SIZE(linkage->prevShader.output_map); i++) {
  54       linkage->prevShader.output_map[i] = INVALID_INDEX;
  55    }
  56
  57    /* Assign input slots for input shader inputs.
  58     * Basically, we want to use the same index for the output shader's outputs
  59     * and the input shader's inputs that should be linked together.
  60     * We'll modify the input shader's inputs to match the output shader.
  61     */
  62    assert(inshader_info->num_inputs <=
  63           ARRAY_SIZE(inshader_info->input_semantic_name));
  64
  65    /* free register index that can be used for built-in varyings */
  66    free_slot = outshader_info->num_outputs + 1;
  67
  68    for (i = 0; i < inshader_info->num_inputs; i++) {
  69       enum tgsi_semantic sem_name = inshader_info->input_semantic_name[i];
  70       unsigned sem_index = inshader_info->input_semantic_index[i];
  71       unsigned j;
  72       unsigned out_index;
  73
  74       /* search output shader outputs for same item */
  75       for (j = 0; j < outshader_info->num_outputs; j++) {
  76          assert(j < ARRAY_SIZE(outshader_info->output_semantic_name));
  77          if (outshader_info->output_semantic_name[j] == sem_name &&
  78              outshader_info->output_semantic_index[j] == sem_index) {
  79             linkage->input_map[i] = j;
  80             linkage->prevShader.output_map[j] = i;
  81             break;
  82          }
  83       }
  84
  85       /**
  86        * The clip distance inputs come from the output shader's
  87        * clip distance shadow copy, so mark the input index to match
  88        * the index of the shadow copy.
  89        */
  90       if (sem_name == TGSI_SEMANTIC_CLIPDIST) {
  91          out_index = outshader_info->num_outputs + 1 + sem_index;
  92          linkage->input_map[i] = out_index;
  93          linkage->prevShader.output_map[out_index] = i;
  94          /* make sure free_slot includes this extra output */
  95          free_slot = MAX2(free_slot, linkage->input_map[i] + 1);
  96       }
  97    }
  98
  99    /* Find the index for position */
 100    linkage->position_index = 0;
 101    for (i = 0; i < outshader_info->num_outputs; i++) {
 102       if (outshader_info->output_semantic_name[i] == TGSI_SEMANTIC_POSITION) {
 103          linkage->position_index = i;
 104          break;
 105       }
 106    }
 107
 108    linkage->num_inputs = inshader_info->num_inputs;
 109    linkage->prevShader.num_outputs = outshader_info->num_outputs;
 110
 111    /* Things like the front-face register are handled here */
 112    for (i = 0; i < inshader_info->num_inputs; i++) {
 113       if (linkage->input_map[i] == INVALID_INDEX) {
 114          unsigned j = free_slot++;
 115          linkage->input_map[i] = j;
 116          linkage->prevShader.output_map[j] = i;
 117       }
 118    }
 119    linkage->input_map_max = free_slot - 1;
 120
 121    /* Debug */
 122    if (SVGA_DEBUG & DEBUG_TGSI) {
 123       uint64_t reg = 0;
 124       uint64_t one = 1;
 125
 126       debug_printf(
 127       "### linkage info: num_inputs=%d input_map_max=%d prevShader.num_outputs=%d\n",
 128                    linkage->num_inputs, linkage->input_map_max,
 129                    linkage->prevShader.num_outputs);
 130
 131       for (i = 0; i < linkage->num_inputs; i++) {
 132
 133          assert(linkage->input_map[i] != INVALID_INDEX);
 134
 135          debug_printf("   input[%d] slot %u  %s %u %s\n",
 136                       i,
 137                       linkage->input_map[i],
 138                       tgsi_semantic_names[inshader_info->input_semantic_name[i]],
 139                       inshader_info->input_semantic_index[i],
 140                       tgsi_interpolate_names[inshader_info->input_interpolate[i]]);
 141
 142          /* make sure no repeating register index */
 143          assert((reg & (one << linkage->input_map[i])) == 0);
 144          reg |= one << linkage->input_map[i];
 145       }
 146    }
 147 }