From 5af1828440fac8215952903bd9e8bbc8b50ec7b8 Mon Sep 17 00:00:00 2001
From: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Date: Thu, 9 May 2024 10:24:23 -0400
Subject: [PATCH] asahi: mv vertex_id_for_topology_class into GS lowering

not used with tess.

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29179>
---
 src/asahi/lib/agx_nir_lower_gs.c | 37 +++++++++++++++++++++++++++++-
 src/asahi/lib/agx_nir_lower_gs.h |  4 ----
 src/asahi/lib/agx_nir_lower_ia.c | 39 +++-----------------------------
 3 files changed, 39 insertions(+), 41 deletions(-)

diff --git a/src/asahi/lib/agx_nir_lower_gs.c b/src/asahi/lib/agx_nir_lower_gs.c
index daf46db4330..2308da298af 100644
--- a/src/asahi/lib/agx_nir_lower_gs.c
+++ b/src/asahi/lib/agx_nir_lower_gs.c
@@ -167,6 +167,41 @@ load_instance_id(nir_builder *b)
    return nir_channel(b, nir_load_global_invocation_id(b, 32), 1);
 }
 
+/* Geometry shaders use software input assembly. The software vertex shader
+ * is invoked for each index, and the geometry shader applies the topology. This
+ * helper applies the topology.
+ */
+static nir_def *
+vertex_id_for_topology_class(nir_builder *b, nir_def *vert, enum mesa_prim cls)
+{
+   nir_def *prim = nir_load_primitive_id(b);
+   nir_def *flatshade_first = nir_ieq_imm(b, nir_load_provoking_last(b), 0);
+   nir_def *nr = nir_load_num_vertices(b);
+   nir_def *topology = nir_load_input_topology_agx(b);
+
+   switch (cls) {
+   case MESA_PRIM_POINTS:
+      return prim;
+
+   case MESA_PRIM_LINES:
+      return libagx_vertex_id_for_line_class(b, topology, prim, vert, nr);
+
+   case MESA_PRIM_TRIANGLES:
+      return libagx_vertex_id_for_tri_class(b, topology, prim, vert,
+                                            flatshade_first);
+
+   case MESA_PRIM_LINES_ADJACENCY:
+      return libagx_vertex_id_for_line_adj_class(b, topology, prim, vert);
+
+   case MESA_PRIM_TRIANGLES_ADJACENCY:
+      return libagx_vertex_id_for_tri_adj_class(b, topology, prim, vert, nr,
+                                                flatshade_first);
+
+   default:
+      unreachable("invalid topology class");
+   }
+}
+
 nir_def *
 agx_load_per_vertex_input(nir_builder *b, nir_intrinsic_instr *intr,
                           nir_def *vertex)
@@ -193,7 +228,7 @@ lower_gs_inputs(nir_builder *b, nir_intrinsic_instr *intr, void *_)
 
    /* Calculate the vertex ID we're pulling, based on the topology class */
    nir_def *vert_in_prim = intr->src[0].ssa;
-   nir_def *vertex = agx_vertex_id_for_topology_class(
+   nir_def *vertex = vertex_id_for_topology_class(
       b, vert_in_prim, b->shader->info.gs.input_primitive);
 
    /* The unrolled vertex ID uses the input_vertices, which differs from what
diff --git a/src/asahi/lib/agx_nir_lower_gs.h b/src/asahi/lib/agx_nir_lower_gs.h
index a5f2a76651a..f73084552f0 100644
--- a/src/asahi/lib/agx_nir_lower_gs.h
+++ b/src/asahi/lib/agx_nir_lower_gs.h
@@ -23,10 +23,6 @@ struct nir_def *agx_load_per_vertex_input(struct nir_builder *b,
                                           nir_intrinsic_instr *intr,
                                           struct nir_def *vertex);
 
-struct nir_def *agx_vertex_id_for_topology_class(struct nir_builder *b,
-                                                 struct nir_def *vert,
-                                                 enum mesa_prim clas);
-
 bool agx_nir_lower_index_buffer(struct nir_shader *s, unsigned index_size_B,
                                 bool patches);
 
diff --git a/src/asahi/lib/agx_nir_lower_ia.c b/src/asahi/lib/agx_nir_lower_ia.c
index 0a0a20f971b..0d846a55006 100644
--- a/src/asahi/lib/agx_nir_lower_ia.c
+++ b/src/asahi/lib/agx_nir_lower_ia.c
@@ -15,43 +15,10 @@
 #include "shader_enums.h"
 
 /*
- * This file implements input assembly in software for geometry/tessellation
- * shaders. load_vertex_id is lowered based on the topology. Most of the logic
- * lives in CL library routines.
+ * This file implements basic input assembly in software. It runs on software
+ * vertex shaders, as part of geometry/tessellation lowering. It does not apply
+ * the topology, which happens in the geometry shader.
  */
-
-nir_def *
-agx_vertex_id_for_topology_class(nir_builder *b, nir_def *vert,
-                                 enum mesa_prim cls)
-{
-   nir_def *prim = nir_load_primitive_id(b);
-   nir_def *flatshade_first = nir_ieq_imm(b, nir_load_provoking_last(b), 0);
-   nir_def *nr = nir_load_num_vertices(b);
-   nir_def *topology = nir_load_input_topology_agx(b);
-
-   switch (cls) {
-   case MESA_PRIM_POINTS:
-      return prim;
-
-   case MESA_PRIM_LINES:
-      return libagx_vertex_id_for_line_class(b, topology, prim, vert, nr);
-
-   case MESA_PRIM_TRIANGLES:
-      return libagx_vertex_id_for_tri_class(b, topology, prim, vert,
-                                            flatshade_first);
-
-   case MESA_PRIM_LINES_ADJACENCY:
-      return libagx_vertex_id_for_line_adj_class(b, topology, prim, vert);
-
-   case MESA_PRIM_TRIANGLES_ADJACENCY:
-      return libagx_vertex_id_for_tri_adj_class(b, topology, prim, vert, nr,
-                                                flatshade_first);
-
-   default:
-      unreachable("invalid topology class");
-   }
-}
-
 struct state {
    unsigned index_size;
    bool patches;