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IABSD.fr/xenocara/lib/mesa/src/intel/compiler/brw_vue_map.c

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  • Author : jsg
    Date : 2025-06-05 14:17:56
    Hash : 452696b8
    Message : Merge Mesa 25.0.7

  • lib/mesa/src/intel/compiler/brw_vue_map.c
  • /*
     * Copyright © 2011 Intel Corporation
     *
     * Permission is hereby granted, free of charge, to any person obtaining a
     * copy of this software and associated documentation files (the "Software"),
     * to deal in the Software without restriction, including without limitation
     * the rights to use, copy, modify, merge, publish, distribute, sublicense,
     * and/or sell copies of the Software, and to permit persons to whom the
     * Software is furnished to do so, subject to the following conditions:
     *
     * The above copyright notice and this permission notice (including the next
     * paragraph) shall be included in all copies or substantial portions of the
     * Software.
     *
     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
     * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
     * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
     * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
     * IN THE SOFTWARE.
     */
    
    /**
     * @file
     *
     * This file computes the "VUE map" for a (non-fragment) shader stage, which
     * describes the layout of its output varyings.  The VUE map is used to match
     * outputs from one stage with the inputs of the next.
     *
     * Largely, varyings can be placed however we like - producers/consumers simply
     * have to agree on the layout.  However, there is also a "VUE Header" that
     * prescribes a fixed-layout for items that interact with fixed function
     * hardware, such as the clipper and rasterizer.
     *
     * Authors:
     *   Paul Berry <stereotype441@gmail.com>
     *   Chris Forbes <chrisf@ijw.co.nz>
     *   Eric Anholt <eric@anholt.net>
     */
    
    
    #include "brw_compiler.h"
    #include "dev/intel_debug.h"
    
    static inline void
    assign_vue_slot(struct intel_vue_map *vue_map, int varying, int slot)
    {
       /* Make sure this varying hasn't been assigned a slot already */
       assert (vue_map->varying_to_slot[varying] == -1);
    
       vue_map->varying_to_slot[varying] = slot;
       vue_map->slot_to_varying[slot] = varying;
    }
    
    /**
     * Compute the VUE map for a shader stage.
     */
    void
    brw_compute_vue_map(const struct intel_device_info *devinfo,
                        struct intel_vue_map *vue_map,
                        uint64_t slots_valid,
                        bool separate,
                        uint32_t pos_slots)
    {
       if (separate) {
          /* In SSO mode, we don't know whether the adjacent stage will
           * read/write gl_ClipDistance, which has a fixed slot location.
           * We have to assume the worst and reserve a slot for it, or else
           * the rest of our varyings will be off by a slot.
           *
           * Note that we don't have to worry about COL/BFC, as those built-in
           * variables only exist in legacy GL, which only supports VS and FS.
           */
          slots_valid |= BITFIELD64_BIT(VARYING_SLOT_CLIP_DIST0);
          slots_valid |= BITFIELD64_BIT(VARYING_SLOT_CLIP_DIST1);
       }
    
       vue_map->slots_valid = slots_valid;
       vue_map->separate = separate;
    
       /* gl_Layer, gl_ViewportIndex & gl_PrimitiveShadingRateEXT don't get their
        * own varying slots -- they are stored in the first VUE slot
        * (VARYING_SLOT_PSIZ).
        */
       slots_valid &= ~(VARYING_BIT_LAYER | VARYING_BIT_VIEWPORT | VARYING_BIT_PRIMITIVE_SHADING_RATE);
    
       /* Make sure that the values we store in vue_map->varying_to_slot and
        * vue_map->slot_to_varying won't overflow the signed chars that are used
        * to store them.  Note that since vue_map->slot_to_varying sometimes holds
        * values equal to BRW_VARYING_SLOT_COUNT, we need to ensure that
        * BRW_VARYING_SLOT_COUNT is <= 127, not 128.
        */
       STATIC_ASSERT(BRW_VARYING_SLOT_COUNT <= 127);
    
       for (int i = 0; i < BRW_VARYING_SLOT_COUNT; ++i) {
          vue_map->varying_to_slot[i] = -1;
          vue_map->slot_to_varying[i] = BRW_VARYING_SLOT_PAD;
       }
    
       int slot = 0;
    
       /* VUE header: format depends on chip generation and whether clipping is
        * enabled.
        *
        * See the Sandybridge PRM, Volume 2 Part 1, section 1.5.1 (page 30),
        * "Vertex URB Entry (VUE) Formats" which describes the VUE header layout.
        *
        * There are 8 or 16 DWs (D0-D15) in VUE header on Sandybridge:
        * dword 0-3 of the header is shading rate, indices, point width, clip flags.
        * dword 4-7 is the 4D space position
        * dword 8-15 of the vertex header is the user clip distance if
        * enabled.
        * dword 8-11 or 16-19 is the first vertex element data we fill.
        */
       assign_vue_slot(vue_map, VARYING_SLOT_PSIZ, slot++);
       assign_vue_slot(vue_map, VARYING_SLOT_POS, slot++);
    
       /* When using Primitive Replication, multiple slots are used for storing
        * positions for each view.
        */
       assert(pos_slots >= 1);
       if (pos_slots > 1) {
          for (int i = 1; i < pos_slots; i++) {
             vue_map->slot_to_varying[slot++] = VARYING_SLOT_POS;
          }
       }
    
       if (slots_valid & BITFIELD64_BIT(VARYING_SLOT_CLIP_DIST0))
          assign_vue_slot(vue_map, VARYING_SLOT_CLIP_DIST0, slot++);
       if (slots_valid & BITFIELD64_BIT(VARYING_SLOT_CLIP_DIST1))
          assign_vue_slot(vue_map, VARYING_SLOT_CLIP_DIST1, slot++);
    
       /* Vertex URB Formats table says: "Vertex Header shall be padded at the
        * end so that the header ends on a 32-byte boundary".
        */
       slot += slot % 2;
    
       /* front and back colors need to be consecutive so that we can use
        * ATTRIBUTE_SWIZZLE_INPUTATTR_FACING to swizzle them when doing
        * two-sided color.
        */
       if (slots_valid & BITFIELD64_BIT(VARYING_SLOT_COL0))
          assign_vue_slot(vue_map, VARYING_SLOT_COL0, slot++);
       if (slots_valid & BITFIELD64_BIT(VARYING_SLOT_BFC0))
          assign_vue_slot(vue_map, VARYING_SLOT_BFC0, slot++);
       if (slots_valid & BITFIELD64_BIT(VARYING_SLOT_COL1))
          assign_vue_slot(vue_map, VARYING_SLOT_COL1, slot++);
       if (slots_valid & BITFIELD64_BIT(VARYING_SLOT_BFC1))
          assign_vue_slot(vue_map, VARYING_SLOT_BFC1, slot++);
    
       /* The hardware doesn't care about the rest of the vertex outputs, so we
        * can assign them however we like.  For normal programs, we simply assign
        * them contiguously.
        *
        * For separate shader pipelines, we first assign built-in varyings
        * contiguous slots.  This works because ARB_separate_shader_objects
        * requires that all shaders have matching built-in varying interface
        * blocks.  Next, we assign generic varyings based on their location
        * (either explicit or linker assigned).  This guarantees a fixed layout.
        *
        * We generally don't need to assign a slot for VARYING_SLOT_CLIP_VERTEX,
        * since it's encoded as the clip distances by emit_clip_distances().
        * However, it may be output by transform feedback, and we'd rather not
        * recompute state when TF changes, so we just always include it.
        */
       uint64_t builtins = slots_valid & BITFIELD64_MASK(VARYING_SLOT_VAR0);
       while (builtins != 0) {
          const int varying = ffsll(builtins) - 1;
          if (vue_map->varying_to_slot[varying] == -1) {
             assign_vue_slot(vue_map, varying, slot++);
          }
          builtins &= ~BITFIELD64_BIT(varying);
       }
    
       const int first_generic_slot = slot;
       uint64_t generics = slots_valid & ~BITFIELD64_MASK(VARYING_SLOT_VAR0);
       while (generics != 0) {
          const int varying = ffsll(generics) - 1;
          if (separate) {
             slot = first_generic_slot + varying - VARYING_SLOT_VAR0;
          }
          assign_vue_slot(vue_map, varying, slot++);
          generics &= ~BITFIELD64_BIT(varying);
       }
    
       vue_map->num_slots = slot;
       vue_map->num_pos_slots = pos_slots;
       vue_map->num_per_vertex_slots = 0;
       vue_map->num_per_patch_slots = 0;
    }
    
    /**
     * Compute the VUE map for tessellation control shader outputs and
     * tessellation evaluation shader inputs.
     */
    void
    brw_compute_tess_vue_map(struct intel_vue_map *vue_map,
                             uint64_t vertex_slots,
                             uint32_t patch_slots)
    {
       /* I don't think anything actually uses this... */
       vue_map->slots_valid = vertex_slots;
    
       /* separate isn't really meaningful, but make sure it's initialized */
       vue_map->separate = false;
    
       vertex_slots &= ~(VARYING_BIT_TESS_LEVEL_OUTER |
                         VARYING_BIT_TESS_LEVEL_INNER);
    
       /* Make sure that the values we store in vue_map->varying_to_slot and
        * vue_map->slot_to_varying won't overflow the signed chars that are used
        * to store them.  Note that since vue_map->slot_to_varying sometimes holds
        * values equal to VARYING_SLOT_TESS_MAX , we need to ensure that
        * VARYING_SLOT_TESS_MAX is <= 127, not 128.
        */
       STATIC_ASSERT(VARYING_SLOT_TESS_MAX <= 127);
    
       for (int i = 0; i < VARYING_SLOT_TESS_MAX ; ++i) {
          vue_map->varying_to_slot[i] = -1;
          vue_map->slot_to_varying[i] = BRW_VARYING_SLOT_PAD;
       }
    
       int slot = 0;
    
       /* The first 8 DWords are reserved for the "Patch Header".
        *
        * VARYING_SLOT_TESS_LEVEL_OUTER / INNER live here, but the exact layout
        * depends on the domain type.  They might not be in slots 0 and 1 as
        * described here, but pretending they're separate allows us to uniquely
        * identify them by distinct slot locations.
        */
       assign_vue_slot(vue_map, VARYING_SLOT_TESS_LEVEL_INNER, slot++);
       assign_vue_slot(vue_map, VARYING_SLOT_TESS_LEVEL_OUTER, slot++);
    
       /* first assign per-patch varyings */
       while (patch_slots != 0) {
          const int varying = ffsll(patch_slots) - 1;
          if (vue_map->varying_to_slot[varying + VARYING_SLOT_PATCH0] == -1) {
             assign_vue_slot(vue_map, varying + VARYING_SLOT_PATCH0, slot++);
          }
          patch_slots &= ~BITFIELD64_BIT(varying);
       }
    
       /* apparently, including the patch header... */
       vue_map->num_per_patch_slots = slot;
    
       /* then assign per-vertex varyings for each vertex in our patch */
       while (vertex_slots != 0) {
          const int varying = ffsll(vertex_slots) - 1;
          if (vue_map->varying_to_slot[varying] == -1) {
             assign_vue_slot(vue_map, varying, slot++);
          }
          vertex_slots &= ~BITFIELD64_BIT(varying);
       }
    
       vue_map->num_per_vertex_slots = slot - vue_map->num_per_patch_slots;
       vue_map->num_pos_slots = 0;
       vue_map->num_slots = slot;
    }
    
    static const char *
    varying_name(brw_varying_slot slot, gl_shader_stage stage)
    {
       assume(slot < BRW_VARYING_SLOT_COUNT);
    
       if (slot < VARYING_SLOT_MAX)
          return gl_varying_slot_name_for_stage((gl_varying_slot)slot, stage);
    
       static const char *brw_names[] = {
          [BRW_VARYING_SLOT_PAD - VARYING_SLOT_MAX] = "BRW_VARYING_SLOT_PAD",
       };
    
       return brw_names[slot - VARYING_SLOT_MAX];
    }
    
    void
    brw_print_vue_map(FILE *fp, const struct intel_vue_map *vue_map,
                      gl_shader_stage stage)
    {
       if (vue_map->num_per_vertex_slots > 0 || vue_map->num_per_patch_slots > 0) {
          fprintf(fp, "PUE map (%d slots, %d/patch, %d/vertex, %s)\n",
                  vue_map->num_slots,
                  vue_map->num_per_patch_slots,
                  vue_map->num_per_vertex_slots,
                  vue_map->separate ? "SSO" : "non-SSO");
          for (int i = 0; i < vue_map->num_slots; i++) {
             if (vue_map->slot_to_varying[i] >= VARYING_SLOT_PATCH0) {
                fprintf(fp, "  [%d] VARYING_SLOT_PATCH%d\n", i,
                        vue_map->slot_to_varying[i] - VARYING_SLOT_PATCH0);
             } else {
                fprintf(fp, "  [%d] %s\n", i,
                        varying_name(vue_map->slot_to_varying[i], stage));
             }
          }
       } else {
          fprintf(fp, "VUE map (%d slots, %s)\n",
                  vue_map->num_slots, vue_map->separate ? "SSO" : "non-SSO");
          for (int i = 0; i < vue_map->num_slots; i++) {
             fprintf(fp, "  [%d] %s\n", i,
                     varying_name(vue_map->slot_to_varying[i], stage));
          }
       }
       fprintf(fp, "\n");
    }