src/gallium/drivers/vc4/vc4_nir_lower_io.c

   1 /*
   2  * Copyright © 2015 Broadcom
   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
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  */
  23
  24 #include "vc4_qir.h"
  25 #include "tgsi/tgsi_info.h"
  26 #include "glsl/nir/nir_builder.h"
  27
  28 /**
  29  * Walks the NIR generated by TGSI-to-NIR to lower its io intrinsics into
  30  * something amenable to the VC4 architecture.
  31  *
  32  * Currently, it split outputs into scalars, and drops any non-position values
  33  * in coordinate shaders.
  34  */
  35
  36 static void
  37 vc4_nir_lower_output(struct vc4_compile *c, nir_builder *b,
  38                      nir_intrinsic_instr *intr)
  39 {
  40         nir_variable *output_var = NULL;
  41         foreach_list_typed(nir_variable, var, node, &c->s->outputs) {
  42                 if (var->data.driver_location == intr->const_index[0]) {
  43                         output_var = var;
  44                         break;
  45                 }
  46         }
  47         assert(output_var);
  48         unsigned semantic_name = output_var->data.location;
  49
  50         if (c->stage == QSTAGE_COORD &&
  51             (semantic_name != TGSI_SEMANTIC_POSITION &&
  52              semantic_name != TGSI_SEMANTIC_PSIZE)) {
  53                 nir_instr_remove(&intr->instr);
  54                 return;
  55         }
  56
  57         /* All TGSI-to-NIR outputs are VEC4. */
  58         assert(intr->num_components == 4);
  59
  60         nir_builder_insert_before_instr(b, &intr->instr);
  61
  62         for (unsigned i = 0; i < intr->num_components; i++) {
  63                 nir_intrinsic_instr *intr_comp =
  64                         nir_intrinsic_instr_create(c->s, nir_intrinsic_store_output);
  65                 intr_comp->num_components = 1;
  66                 intr_comp->const_index[0] = intr->const_index[0] * 4 + i;
  67
  68                 assert(intr->src[0].is_ssa);
  69                 intr_comp->src[0] = nir_src_for_ssa(nir_swizzle(b,
  70                                                                 intr->src[0].ssa,
  71                                                                 &i, 1, false));
  72                 nir_builder_instr_insert(b, &intr_comp->instr);
  73         }
  74
  75         nir_instr_remove(&intr->instr);
  76 }
  77
  78 static void
  79 vc4_nir_lower_io_instr(struct vc4_compile *c, nir_builder *b,
  80                        struct nir_instr *instr)
  81 {
  82         if (instr->type != nir_instr_type_intrinsic)
  83                 return;
  84         nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
  85
  86         switch (intr->intrinsic) {
  87         case nir_intrinsic_store_output:
  88                 vc4_nir_lower_output(c, b, intr);
  89                 break;
  90
  91         default:
  92                 break;
  93         }
  94 }
  95
  96 static bool
  97 vc4_nir_lower_io_block(nir_block *block, void *arg)
  98 {
  99         struct vc4_compile *c = arg;
 100         nir_function_impl *impl =
 101                 nir_cf_node_get_function(&block->cf_node);
 102
 103         nir_builder b;
 104         nir_builder_init(&b, impl);
 105
 106         nir_foreach_instr_safe(block, instr)
 107                 vc4_nir_lower_io_instr(c, &b, instr);
 108
 109         return true;
 110 }
 111
 112 static bool
 113 vc4_nir_lower_io_impl(struct vc4_compile *c, nir_function_impl *impl)
 114 {
 115         nir_foreach_block(impl, vc4_nir_lower_io_block, c);
 116
 117         nir_metadata_preserve(impl, nir_metadata_block_index |
 118                               nir_metadata_dominance);
 119
 120         return true;
 121 }
 122
 123 void
 124 vc4_nir_lower_io(struct vc4_compile *c)
 125 {
 126         nir_foreach_overload(c->s, overload) {
 127                 if (overload->impl)
 128                         vc4_nir_lower_io_impl(c, overload->impl);
 129         }
 130 }