Mesa (staging/22.1): zink: handle max_vertices=0 in geometry shader

[GitLab Mirror]

Module: Mesa
Branch: staging/22.1
Commit: 955729649a88c6e2d5ac5aad186cd639bf359fa4
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=955729649a88c6e2d5ac5aad186cd639bf359fa4

Author: Mike Blumenkrantz <michael.blumenkrantz at gmail.com>
Date:   Mon Jul 11 12:04:22 2022 -0400

zink: handle max_vertices=0 in geometry shader

this is a weird corner case where glsl permits a zero value, so clamp to 1
and then don't emit any vertices to avoid driver hangs

affects:
dEQP-GL45-ES31.functional.geometry_shading.emit.points_emit_0_end_0

cc: mesa-stable

Reviewed-by: Dave Airlie <airlied at redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17639>
(cherry picked from commit 5b58f8df538f9bb7489486d262a6e603ddfa1f65)

---

 .pick_status.json                                    | 2 +-
 src/gallium/drivers/zink/nir_to_spirv/nir_to_spirv.c | 7 ++++---
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/.pick_status.json b/.pick_status.json
index 9c1b67d51ca..b3a73bda63e 100644
--- a/.pick_status.json
+++ b/.pick_status.json
@@ -3658,7 +3658,7 @@
         "description": "zink: handle max_vertices=0 in geometry shader",
         "nominated": true,
         "nomination_type": 0,
-        "resolution": 0,
+        "resolution": 1,
         "main_sha": null,
         "because_sha": null
     },
diff --git a/src/gallium/drivers/zink/nir_to_spirv/nir_to_spirv.c b/src/gallium/drivers/zink/nir_to_spirv/nir_to_spirv.c
index cbd1d55493e..e5d4ad10c58 100644
--- a/src/gallium/drivers/zink/nir_to_spirv/nir_to_spirv.c
+++ b/src/gallium/drivers/zink/nir_to_spirv/nir_to_spirv.c
@@ -2903,8 +2903,9 @@ emit_intrinsic(struct ntv_context *ctx, nir_intrinsic_instr *intr)
        */
       if (ctx->sinfo)
          emit_so_outputs(ctx, ctx->sinfo);
-      spirv_builder_emit_vertex(&ctx->builder, nir_intrinsic_stream_id(intr),
-                                ctx->nir->info.stage == MESA_SHADER_GEOMETRY && util_bitcount(ctx->nir->info.gs.active_stream_mask) > 1);
+      if (ctx->nir->info.gs.vertices_out) //skip vertex emission if !vertices_out
+         spirv_builder_emit_vertex(&ctx->builder, nir_intrinsic_stream_id(intr),
+                                   ctx->nir->info.stage == MESA_SHADER_GEOMETRY && util_bitcount(ctx->nir->info.gs.active_stream_mask) > 1);
       break;
 
    case nir_intrinsic_set_vertex_and_primitive_count:
@@ -4152,7 +4153,7 @@ nir_to_spirv(struct nir_shader *s, const struct zink_shader_info *sinfo, uint32_
                                            s->info.gs.invocations);
       spirv_builder_emit_exec_mode_literal(&ctx.builder, entry_point,
                                            SpvExecutionModeOutputVertices,
-                                           s->info.gs.vertices_out);
+                                           MAX2(s->info.gs.vertices_out, 1));
       break;
    case MESA_SHADER_COMPUTE:
       if (s->info.shared_size)