agx: Remap varyings to match AGX ABI

It's not clear if this is software or hardware defined, but until we
know more about linkage, let's match the blob. Fixes dEQP issues with
gl_PointSize.

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Acked-by: Jason Ekstrand <jason@jlekstrand.net>
Acked-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/10582>

diff --git a/src/asahi/compiler/agx_compile.c b/src/asahi/compiler/agx_compile.c
index 7150d7a..aabfc50 100644 (file)
--- a/src/asahi/compiler/agx_compile.c
+++ b/src/asahi/compiler/agx_compile.c
@@ -133,6 +133,36 @@ agx_optimize_nir(nir_shader *nir)
    NIR_PASS_V(nir, nir_opt_move, move_all);
 }
 
+/* ABI: position first, then user, then psiz */
+static void
+agx_remap_varyings(nir_shader *nir)
+{
+   unsigned base = 0;
+
+   nir_variable *pos = nir_find_variable_with_location(nir, nir_var_shader_out, VARYING_SLOT_POS);
+   if (pos) {
+      pos->data.driver_location = base;
+      base += 4;
+   }
+
+   nir_foreach_shader_out_variable(var, nir) {
+      unsigned loc = var->data.location;
+
+      if(loc == VARYING_SLOT_POS || loc == VARYING_SLOT_PSIZ) {
+         continue;
+      }
+
+      var->data.driver_location = base;
+      base += 4;
+   }
+
+   nir_variable *psiz = nir_find_variable_with_location(nir, nir_var_shader_out, VARYING_SLOT_PSIZ);
+   if (psiz) {
+      psiz->data.driver_location = base;
+      base += 1;
+   }
+}
+
 void
 agx_compile_shader_nir(nir_shader *nir,
       struct agx_shader_key *key,
@@ -155,6 +185,9 @@ agx_compile_shader_nir(nir_shader *nir,
          glsl_get_natural_size_align_bytes);
    NIR_PASS_V(nir, nir_lower_indirect_derefs, nir_var_function_temp, ~0);
 
+   if (ctx->stage == MESA_SHADER_VERTEX)
+      agx_remap_varyings(nir);
+
    NIR_PASS_V(nir, nir_split_var_copies);
    NIR_PASS_V(nir, nir_lower_global_vars_to_local);
    NIR_PASS_V(nir, nir_lower_var_copies);