src/compiler/nir/nir_lower_clamp_color_outputs.c

   1 /*
   2  * Copyright © 2015 Red Hat
   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 FROM,
  20  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  21  * SOFTWARE.
  22  */
  23
  24
  25 #include "nir.h"
  26 #include "nir_builder.h"
  27
  28 typedef struct {
  29    nir_shader *shader;
  30    nir_builder b;
  31 } lower_state;
  32
  33 static bool
  34 is_color_output(lower_state *state, nir_variable *out)
  35 {
  36    switch (state->shader->info.stage) {
  37    case MESA_SHADER_VERTEX:
  38    case MESA_SHADER_GEOMETRY:
  39       switch (out->data.location) {
  40       case VARYING_SLOT_COL0:
  41       case VARYING_SLOT_COL1:
  42       case VARYING_SLOT_BFC0:
  43       case VARYING_SLOT_BFC1:
  44          return true;
  45       default:
  46          return false;
  47       }
  48       break;
  49    case MESA_SHADER_FRAGMENT:
  50       switch (out->data.location) {
  51       case FRAG_RESULT_COLOR:
  52          return true;
  53       default:
  54          return false;
  55       }
  56       break;
  57    default:
  58       return false;
  59    }
  60 }
  61
  62 static bool
  63 lower_intrinsic(lower_state *state, nir_intrinsic_instr *intr)
  64 {
  65    nir_variable *out = NULL;
  66    nir_builder *b = &state->b;
  67    nir_ssa_def *s;
  68
  69    switch (intr->intrinsic) {
  70    case nir_intrinsic_store_var:
  71       out = intr->variables[0]->var;
  72       break;
  73    case nir_intrinsic_store_output:
  74       /* already had i/o lowered.. lookup the matching output var: */
  75       nir_foreach_variable(var, &state->shader->outputs) {
  76          int drvloc = var->data.driver_location;
  77          if (nir_intrinsic_base(intr) == drvloc) {
  78             out = var;
  79             break;
  80          }
  81       }
  82       assume(out);
  83       break;
  84    default:
  85       return false;
  86    }
  87
  88    if (out->data.mode != nir_var_shader_out)
  89       return false;
  90
  91    if (is_color_output(state, out)) {
  92       b->cursor = nir_before_instr(&intr->instr);
  93       s = nir_ssa_for_src(b, intr->src[0], intr->num_components);
  94       s = nir_fsat(b, s);
  95       nir_instr_rewrite_src(&intr->instr, &intr->src[0], nir_src_for_ssa(s));
  96    }
  97
  98    return true;
  99 }
 100
 101 static bool
 102 lower_block(lower_state *state, nir_block *block)
 103 {
 104    bool progress = false;
 105
 106    nir_foreach_instr_safe(instr, block) {
 107       if (instr->type == nir_instr_type_intrinsic)
 108          progress |= lower_intrinsic(state, nir_instr_as_intrinsic(instr));
 109    }
 110
 111    return progress;
 112 }
 113
 114 static bool
 115 lower_impl(lower_state *state, nir_function_impl *impl)
 116 {
 117    nir_builder_init(&state->b, impl);
 118    bool progress = false;
 119
 120    nir_foreach_block(block, impl) {
 121       progress |= lower_block(state, block);
 122    }
 123    nir_metadata_preserve(impl, nir_metadata_block_index |
 124                                nir_metadata_dominance);
 125
 126    return progress;
 127 }
 128
 129 bool
 130 nir_lower_clamp_color_outputs(nir_shader *shader)
 131 {
 132    bool progress = false;
 133    lower_state state = {
 134       .shader = shader,
 135    };
 136
 137    nir_foreach_function(function, shader) {
 138       if (function->impl)
 139          progress |= lower_impl(&state, function->impl);
 140    }
 141
 142    return progress;
 143 }