src/intel/compiler/brw_nir_attribute_workarounds.c

   1 /*
   2  * Copyright © 2016 Intel Corporation
   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 "compiler/nir/nir_builder.h"
  25 #include "brw_nir.h"
  26
  27 /**
  28  * Prior to Haswell, the hardware can't natively support GL_FIXED or
  29  * 2_10_10_10_REV vertex formats.  This pass inserts extra shader code
  30  * to produce the correct values.
  31  */
  32
  33 struct attr_wa_state {
  34    nir_builder builder;
  35    bool impl_progress;
  36    const uint8_t *wa_flags;
  37 };
  38
  39 static bool
  40 apply_attr_wa_block(nir_block *block, struct attr_wa_state *state)
  41 {
  42    nir_builder *b = &state->builder;
  43
  44    nir_foreach_instr_safe(instr, block) {
  45       if (instr->type != nir_instr_type_intrinsic)
  46          continue;
  47
  48       nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
  49       if (intrin->intrinsic != nir_intrinsic_load_input)
  50          continue;
  51
  52       uint8_t wa_flags = state->wa_flags[intrin->const_index[0]];
  53       if (wa_flags == 0)
  54          continue;
  55
  56       b->cursor = nir_after_instr(instr);
  57
  58       nir_ssa_def *val = &intrin->dest.ssa;
  59
  60       /* Do GL_FIXED rescaling for GLES2.0.  Our GL_FIXED attributes
  61        * come in as floating point conversions of the integer values.
  62        */
  63       if (wa_flags & BRW_ATTRIB_WA_COMPONENT_MASK) {
  64          nir_ssa_def *scaled =
  65             nir_fmul(b, val, nir_imm_float(b, 1.0f / 65536.0f));
  66          nir_ssa_def *comps[4];
  67          for (int i = 0; i < val->num_components; i++) {
  68             bool rescale = i < (wa_flags & BRW_ATTRIB_WA_COMPONENT_MASK);
  69             comps[i] = nir_channel(b, rescale ? scaled : val, i);
  70          }
  71          val = nir_vec(b, comps, val->num_components);
  72       }
  73
  74       /* Do sign recovery for 2101010 formats if required. */
  75       if (wa_flags & BRW_ATTRIB_WA_SIGN) {
  76          /* sign recovery shift: <22, 22, 22, 30> */
  77          nir_ssa_def *shift = nir_imm_ivec4(b, 22, 22, 22, 30);
  78          val = nir_ishr(b, nir_ishl(b, val, shift), shift);
  79       }
  80
  81       /* Apply BGRA swizzle if required. */
  82       if (wa_flags & BRW_ATTRIB_WA_BGRA) {
  83          val = nir_swizzle(b, val, (unsigned[4]){2,1,0,3}, 4);
  84       }
  85
  86       if (wa_flags & BRW_ATTRIB_WA_NORMALIZE) {
  87          /* ES 3.0 has different rules for converting signed normalized
  88           * fixed-point numbers than desktop GL.
  89           */
  90          if (wa_flags & BRW_ATTRIB_WA_SIGN) {
  91             /* According to equation 2.2 of the ES 3.0 specification,
  92              * signed normalization conversion is done by:
  93              *
  94              * f = c / (2^(b-1)-1)
  95              *
  96              * OpenGL 4.2+ uses this equation as well.  Since most contexts
  97              * promote to the new higher version, and this is what Haswell+
  98              * hardware does anyway, we just always use this formula.
  99              */
 100             nir_ssa_def *es3_normalize_factor =
 101                nir_imm_vec4(b, 1.0f / ((1 << 9) - 1), 1.0f / ((1 << 9) - 1),
 102                                1.0f / ((1 << 9) - 1), 1.0f / ((1 << 1) - 1));
 103             val = nir_fmax(b,
 104                            nir_fmul(b, nir_i2f32(b, val), es3_normalize_factor),
 105                            nir_imm_float(b, -1.0f));
 106          } else {
 107             /* The following equation is from the OpenGL 3.2 specification:
 108              *
 109              * 2.1 unsigned normalization
 110              * f = c/(2^n-1)
 111              */
 112             nir_ssa_def *normalize_factor =
 113                nir_imm_vec4(b, 1.0f / ((1 << 10) - 1), 1.0f / ((1 << 10) - 1),
 114                                1.0f / ((1 << 10) - 1), 1.0f / ((1 << 2)  - 1));
 115
 116             val = nir_fmul(b, nir_u2f32(b, val), normalize_factor);
 117          }
 118       }
 119
 120       if (wa_flags & BRW_ATTRIB_WA_SCALE) {
 121          val = (wa_flags & BRW_ATTRIB_WA_SIGN) ? nir_i2f32(b, val)
 122                                                : nir_u2f32(b, val);
 123       }
 124
 125       nir_ssa_def_rewrite_uses_after(&intrin->dest.ssa, nir_src_for_ssa(val),
 126                                      val->parent_instr);
 127       state->impl_progress = true;
 128    }
 129
 130    return true;
 131 }
 132
 133 bool
 134 brw_nir_apply_attribute_workarounds(nir_shader *shader,
 135                                     const uint8_t *attrib_wa_flags)
 136 {
 137    bool progress = false;
 138    struct attr_wa_state state = {
 139       .wa_flags = attrib_wa_flags,
 140    };
 141
 142    nir_foreach_function(func, shader) {
 143       if (!func->impl)
 144          continue;
 145
 146       nir_builder_init(&state.builder, func->impl);
 147       state.impl_progress = false;
 148
 149       nir_foreach_block(block, func->impl) {
 150          apply_attr_wa_block(block, &state);
 151       }
 152
 153       if (state.impl_progress) {
 154          nir_metadata_preserve(func->impl, nir_metadata_block_index |
 155                                            nir_metadata_dominance);
 156          progress = true;
 157       }
 158    }
 159
 160    return progress;
 161 }