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       return (out->data.location == FRAG_RESULT_COLOR ||
  51               out->data.location >= FRAG_RESULT_DATA0);
  52    default:
  53       return false;
  54    }
  55 }
  56
  57 static bool
  58 lower_intrinsic(lower_state *state, nir_intrinsic_instr *intr)
  59 {
  60    nir_variable *out = NULL;
  61    nir_builder *b = &state->b;
  62    nir_ssa_def *s;
  63
  64    switch (intr->intrinsic) {
  65    case nir_intrinsic_store_deref:
  66       out = nir_deref_instr_get_variable(nir_src_as_deref(intr->src[0]));
  67       break;
  68    case nir_intrinsic_store_output:
  69       /* already had i/o lowered.. lookup the matching output var: */
  70       nir_foreach_variable(var, &state->shader->outputs) {
  71          int drvloc = var->data.driver_location;
  72          if (nir_intrinsic_base(intr) == drvloc) {
  73             out = var;
  74             break;
  75          }
  76       }
  77       assume(out);
  78       break;
  79    default:
  80       return false;
  81    }
  82
  83    if (out->data.mode != nir_var_shader_out)
  84       return false;
  85
  86    if (is_color_output(state, out)) {
  87       b->cursor = nir_before_instr(&intr->instr);
  88       int src = intr->intrinsic == nir_intrinsic_store_deref ? 1 : 0;
  89       s = nir_ssa_for_src(b, intr->src[src], intr->num_components);
  90       s = nir_fsat(b, s);
  91       nir_instr_rewrite_src(&intr->instr, &intr->src[src], nir_src_for_ssa(s));
  92    }
  93
  94    return true;
  95 }
  96
  97 static bool
  98 lower_block(lower_state *state, nir_block *block)
  99 {
 100    bool progress = false;
 101
 102    nir_foreach_instr_safe(instr, block) {
 103       if (instr->type == nir_instr_type_intrinsic)
 104          progress |= lower_intrinsic(state, nir_instr_as_intrinsic(instr));
 105    }
 106
 107    return progress;
 108 }
 109
 110 static bool
 111 lower_impl(lower_state *state, nir_function_impl *impl)
 112 {
 113    nir_builder_init(&state->b, impl);
 114    bool progress = false;
 115
 116    nir_foreach_block(block, impl) {
 117       progress |= lower_block(state, block);
 118    }
 119    nir_metadata_preserve(impl, nir_metadata_block_index |
 120                                nir_metadata_dominance);
 121
 122    return progress;
 123 }
 124
 125 bool
 126 nir_lower_clamp_color_outputs(nir_shader *shader)
 127 {
 128    bool progress = false;
 129    lower_state state = {
 130       .shader = shader,
 131    };
 132
 133    nir_foreach_function(function, shader) {
 134       if (function->impl)
 135          progress |= lower_impl(&state, function->impl);
 136    }
 137
 138    return progress;
 139 }