asahi: Add GS lowering pass

The big monster.

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/26056>

src/asahi/lib/agx_nir_lower_gs.h

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2023 Alyssa Rosenzweig
+ * SPDX-License-Identifier: MIT
+ */
+
+#ifndef __AGX_NIR_LOWER_GS_H
+#define __AGX_NIR_LOWER_GS_H
+
+#include <stdbool.h>
+
+struct nir_shader;
+struct agx_ia_key;
+enum mesa_prim;
+
+void agx_nir_lower_gs(struct nir_shader *gs, struct nir_shader *vs,
+                      const struct nir_shader *libagx, struct agx_ia_key *ia,
+                      bool rasterizer_discard, struct nir_shader **gs_count,
+                      struct nir_shader **gs_copy, struct nir_shader **pre_gs,
+                      enum mesa_prim *out_mode, unsigned *out_count_words);
+
+struct nir_shader *agx_nir_prefix_sum_gs(const struct nir_shader *libagx,
+                                         unsigned words);
+
+struct nir_shader *agx_nir_gs_setup_indirect(const struct nir_shader *libagx,
+                                             enum mesa_prim prim);
+
+#endif