/**
* @file brw_vue_map.c
*
+ * 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>
*/
-#include "main/compiler.h"
#include "brw_context.h"
static inline void
-assign_vue_slot(struct brw_vue_map *vue_map, int varying)
+assign_vue_slot(struct brw_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] = vue_map->num_slots;
- vue_map->slot_to_varying[vue_map->num_slots++] = varying;
+ vue_map->varying_to_slot[varying] = slot;
+ vue_map->slot_to_varying[slot] = varying;
}
/**
- * Compute the VUE map for vertex shader program.
+ * Compute the VUE map for a shader stage.
*/
void
-brw_compute_vue_map(const struct brw_device_info *devinfo,
+brw_compute_vue_map(const struct gen_device_info *devinfo,
struct brw_vue_map *vue_map,
- GLbitfield64 slots_valid)
+ GLbitfield64 slots_valid,
+ bool separate)
{
+ /* Keep using the packed/contiguous layout on old hardware - we only need
+ * the SSO layout when using geometry/tessellation shaders or 32 FS input
+ * varyings, which only exist on Gen >= 6. It's also a bit more efficient.
+ */
+ if (devinfo->gen < 6)
+ separate = false;
+
vue_map->slots_valid = slots_valid;
- int i;
+ vue_map->separate = separate;
/* gl_Layer and gl_ViewportIndex don't get their own varying slots -- they
* are stored in the first VUE slot (VARYING_SLOT_PSIZ).
*/
STATIC_ASSERT(BRW_VARYING_SLOT_COUNT <= 127);
- vue_map->num_slots = 0;
- for (i = 0; i < BRW_VARYING_SLOT_COUNT; ++i) {
+ 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_COUNT;
+ 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.
*/
if (devinfo->gen < 6) {
/* There are 8 dwords in VUE header pre-Ironlake:
* On Ironlake the VUE header is nominally 20 dwords, but the hardware
* will accept the same header layout as Gen4 [and should be a bit faster]
*/
- assign_vue_slot(vue_map, VARYING_SLOT_PSIZ);
- assign_vue_slot(vue_map, BRW_VARYING_SLOT_NDC);
- assign_vue_slot(vue_map, VARYING_SLOT_POS);
+ assign_vue_slot(vue_map, VARYING_SLOT_PSIZ, slot++);
+ assign_vue_slot(vue_map, BRW_VARYING_SLOT_NDC, slot++);
+ assign_vue_slot(vue_map, VARYING_SLOT_POS, slot++);
} else {
/* There are 8 or 16 DWs (D0-D15) in VUE header on Sandybridge:
* dword 0-3 of the header is indices, point width, clip flags.
* enabled.
* dword 8-11 or 16-19 is the first vertex element data we fill.
*/
- assign_vue_slot(vue_map, VARYING_SLOT_PSIZ);
- assign_vue_slot(vue_map, VARYING_SLOT_POS);
+ assign_vue_slot(vue_map, VARYING_SLOT_PSIZ, slot++);
+ assign_vue_slot(vue_map, VARYING_SLOT_POS, slot++);
if (slots_valid & BITFIELD64_BIT(VARYING_SLOT_CLIP_DIST0))
- assign_vue_slot(vue_map, 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);
+ assign_vue_slot(vue_map, VARYING_SLOT_CLIP_DIST1, slot++);
/* 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);
+ 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);
+ 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);
+ 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);
+ assign_vue_slot(vue_map, VARYING_SLOT_BFC1, slot++);
}
- /* The hardware doesn't care about the rest of the vertex outputs, so just
- * assign them contiguously. Don't reassign outputs that already have a
- * 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.
*/
- for (int i = 0; i < VARYING_SLOT_MAX; ++i) {
- if ((slots_valid & BITFIELD64_BIT(i)) &&
- vue_map->varying_to_slot[i] == -1) {
- assign_vue_slot(vue_map, i);
+ GLbitfield64 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;
+ GLbitfield64 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);
+ } else {
+ assign_vue_slot(vue_map, varying, slot++);
+ }
+ generics &= ~BITFIELD64_BIT(varying);
+ }
+
+ vue_map->num_slots = separate ? slot + 1 : slot;
+ 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 brw_vue_map *vue_map,
+ GLbitfield64 vertex_slots,
+ GLbitfield patch_slots)
+{
+ /* I don't think anything actually uses this... */
+ vue_map->slots_valid = vertex_slots;
+
+ 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_slots = slot;
+}
+
+static const char *
+varying_name(brw_varying_slot slot)
+{
+ assume(slot < BRW_VARYING_SLOT_COUNT);
+
+ if (slot < VARYING_SLOT_MAX)
+ return gl_varying_slot_name(slot);
+
+ static const char *brw_names[] = {
+ [BRW_VARYING_SLOT_NDC - VARYING_SLOT_MAX] = "BRW_VARYING_SLOT_NDC",
+ [BRW_VARYING_SLOT_PAD - VARYING_SLOT_MAX] = "BRW_VARYING_SLOT_PAD",
+ [BRW_VARYING_SLOT_PNTC - VARYING_SLOT_MAX] = "BRW_VARYING_SLOT_PNTC",
+ };
+
+ return brw_names[slot - VARYING_SLOT_MAX];
+}
+
+void
+brw_print_vue_map(FILE *fp, const struct brw_vue_map *vue_map)
+{
+ 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]));
+ }
+ }
+ } 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]));
}
}
+ fprintf(fp, "\n");
}