panvk: fix executable properties handling for IDVS varying shaders

The previous implementation assumed that VS would have exactly two
executables, the HW variant position shader and the HW variant varying
shader, and that non-VS shaders would only have one executable per
variant. These assumptions are violated by avalon (which only has one
IDVS executable), by SW VS (which is a second VS variant, for three
total variants) and GS rast variants (which execute as a VS on the
hardware and so have two executables pre-avalon).

The new logic allows VS-staged variants to occur as a variant in any API
shader stage, and gives them either one or two executable indices
depending on whether the secondary is used.

Signed-off-by: Olivia Lee <olivia.lee@collabora.com>
Fixes: ff9907927f (panvk: Add basic infrastructure for shader variants)
Reviewed-by: Christoph Pillmayer <christoph.pillmayer@arm.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/41631>

src/panfrost/vulkan/panvk_vX_shader.c

@@ -1971,9 +1971,8 @@ panvk_shader_get_executable_properties(
                           executable_count);
 
    panvk_shader_foreach_variant(shader, variant) {
-      /* Ignore absent variants but always add vertex on IDVS */
-      if (variant->bin_size == 0 &&
-          (variant->info.stage != MESA_SHADER_VERTEX || !variant->info.vs.idvs))
+      /* Ignore absent variants */
+      if (variant->bin_size == 0)
          continue;
 
       const char *variant_name = panvk_shader_variant_name(shader, variant);
@@ -1994,14 +1993,24 @@ panvk_shader_get_executable_properties(
          }
       }
 
-      if (variant->info.stage == MESA_SHADER_VERTEX && variant->info.vs.idvs) {
+      if (variant->info.stage == MESA_SHADER_VERTEX &&
+          variant->info.vs.secondary_offset) {
          vk_outarray_append_typed(VkPipelineExecutablePropertiesKHR, &out,
                                   props)
          {
             props->stages = mesa_to_vk_shader_stage(shader->vk.stage);
             props->subgroupSize = pan_subgroup_size(PAN_ARCH);
-            VK_COPY_STR(props->name, "varying");
-            VK_COPY_STR(props->description, "varying shader");
+
+            if (variant_name != NULL) {
+               VK_PRINT_STR(props->name, "%s %s varying", variant_name,
+                            stage_name);
+               VK_PRINT_STR(props->description, "%s %s varying shader",
+                            variant_name, stage_name);
+            } else {
+               VK_PRINT_STR(props->name, "%s varying", stage_name);
+               VK_PRINT_STR(props->description, "%s varying shader",
+                            stage_name);
+            }
          }
       }
    }
@@ -2011,20 +2020,35 @@ panvk_shader_get_executable_properties(
 
 static const struct panvk_shader_variant *
 get_variant_from_executable_index(struct panvk_shader *shader,
-                                  uint32_t executable_index)
+                                  uint32_t executable_index,
+                                  bool *idvs_varying)
 {
+   *idvs_varying = false;
    uint32_t i = 0;
 
    panvk_shader_foreach_variant(shader, variant) {
-      /* Ignore absent variants but always add vertex on IDVS */
-      if (variant->bin_size == 0 &&
-          (variant->info.stage != MESA_SHADER_VERTEX || !variant->info.vs.idvs))
+      /* Ignore absent variants */
+      if (variant->bin_size == 0)
          continue;
 
       if (i == executable_index)
          return variant;
 
       i++;
+
+      /* VS variants that have a separate IDVS varying shader get two indices,
+       * the first for the position shader and the second for the varying
+       * shader
+       */
+      if (variant->info.stage == MESA_SHADER_VERTEX &&
+          variant->info.vs.secondary_offset) {
+         if (i == executable_index) {
+            *idvs_varying = true;
+            return variant;
+         }
+
+         i++;
+      }
    }
 
    return NULL;
@@ -2040,25 +2064,14 @@ panvk_shader_get_executable_statistics(
       container_of(vk_shader, struct panvk_shader, vk);
 
    bool needs_vary = false;
-   if (shader->vk.stage == MESA_SHADER_VERTEX) {
-      assert(executable_index == 0 || executable_index == 1);
 
-      needs_vary = executable_index == 1;
-
-      /* Readjust index to skip embedded varying variant */
-      if (executable_index >= 1)
-         executable_index--;
-   }
-
-   assert(executable_index < panvk_shader_num_variants(shader->vk.stage));
    const struct panvk_shader_variant *variant =
-      get_variant_from_executable_index(shader, executable_index);
+      get_variant_from_executable_index(shader, executable_index, &needs_vary);
    assert(variant != NULL);
 
    VK_OUTARRAY_MAKE_TYPED(VkPipelineExecutableStatisticKHR, out, statistics,
                           statistic_count);
 
-   assert(executable_index == 0 || executable_index == 1);
    const struct pan_stats *stats =
       needs_vary ? &variant->info.stats_idvs_varying : &variant->info.stats;
 
@@ -2101,25 +2114,15 @@ panvk_shader_get_executable_internal_representations(
                           internal_representation_count);
 
    bool needs_vary = false;
-   if (shader->vk.stage == MESA_SHADER_VERTEX) {
-      assert(executable_index == 0 || executable_index == 1);
 
-      needs_vary = executable_index == 1;
-
-      /* Readjust index to skip embedded varying variant */
-      if (executable_index >= 1)
-         executable_index--;
-   }
+   const struct panvk_shader_variant *variant =
+      get_variant_from_executable_index(shader, executable_index, &needs_vary);
+   assert(variant != NULL);
 
    /* XXX: Varying shader assembly */
    if (needs_vary)
       return vk_outarray_status(&out);
 
-   assert(executable_index < panvk_shader_num_variants(shader->vk.stage));
-   const struct panvk_shader_variant *variant =
-      get_variant_from_executable_index(shader, executable_index);
-   assert(variant != NULL);
-
    bool incomplete_text = false;
 
    if (variant->nir_str != NULL) {