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    case MESA_SHADER_TESS_EVAL:
  40       switch (out->data.location) {
  41       case VARYING_SLOT_COL0:
  42       case VARYING_SLOT_COL1:
  43       case VARYING_SLOT_BFC0:
  44       case VARYING_SLOT_BFC1:
  45          return true;
  46       default:
  47          return false;
  48       }
  49       break;
  50    case MESA_SHADER_FRAGMENT:
  51       return (out->data.location == FRAG_RESULT_COLOR ||
  52               out->data.location >= FRAG_RESULT_DATA0);
  53    default:
  54       return false;
  55    }
  56 }
  57
  58 static bool
  59 lower_intrinsic(lower_state *state, nir_intrinsic_instr *intr)
  60 {
  61    nir_variable *out = NULL;
  62    nir_builder *b = &state->b;
  63    nir_ssa_def *s;
  64
  65    switch (intr->intrinsic) {
  66    case nir_intrinsic_store_deref:
  67       out = nir_deref_instr_get_variable(nir_src_as_deref(intr->src[0]));
  68       break;
  69    case nir_intrinsic_store_output:
  70       /* already had i/o lowered.. lookup the matching output var: */
  71       nir_foreach_shader_out_variable(var, state->shader) {
  72          int drvloc = var->data.driver_location;
  73          if (nir_intrinsic_base(intr) == drvloc) {
  74             out = var;
  75             break;
  76          }
  77       }
  78       assume(out);
  79       break;
  80    default:
  81       return false;
  82    }
  83
  84    if (out->data.mode != nir_var_shader_out)
  85       return false;
  86
  87    if (is_color_output(state, out)) {
  88       b->cursor = nir_before_instr(&intr->instr);
  89       int src = intr->intrinsic == nir_intrinsic_store_deref ? 1 : 0;
  90       s = nir_ssa_for_src(b, intr->src[src], intr->num_components);
  91       s = nir_fsat(b, s);
  92       nir_instr_rewrite_src(&intr->instr, &intr->src[src], nir_src_for_ssa(s));
  93    }
  94
  95    return true;
  96 }
  97
  98 static bool
  99 lower_block(lower_state *state, nir_block *block)
 100 {
 101    bool progress = false;
 102
 103    nir_foreach_instr_safe(instr, block) {
 104       if (instr->type == nir_instr_type_intrinsic)
 105          progress |= lower_intrinsic(state, nir_instr_as_intrinsic(instr));
 106    }
 107
 108    return progress;
 109 }
 110
 111 static bool
 112 lower_impl(lower_state *state, nir_function_impl *impl)
 113 {
 114    nir_builder_init(&state->b, impl);
 115    bool progress = false;
 116
 117    nir_foreach_block(block, impl) {
 118       progress |= lower_block(state, block);
 119    }
 120    nir_metadata_preserve(impl, nir_metadata_block_index |
 121                                nir_metadata_dominance);
 122
 123    return progress;
 124 }
 125
 126 bool
 127 nir_lower_clamp_color_outputs(nir_shader *shader)
 128 {
 129    bool progress = false;
 130    lower_state state = {
 131       .shader = shader,
 132    };
 133
 134    nir_foreach_function(function, shader) {
 135       if (function->impl)
 136          progress |= lower_impl(&state, function->impl);
 137    }
 138
 139    return progress;
 140 }