panfrost: Add a knob to disable the UBO -> push constants optimization

I'm just too lazy to implement the logic to prepare push constant
buffers in the Vulkan driver. Besides, Vulkan has explicit push
constants, which AFAIK is not handled in the compiler backends yet,
and that will probably conflict with the UBO -> push constant
promotion.

Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Alyssa Rosenzweig <alyssa@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/9517>

src/panfrost/bifrost/bi_opt_push_ubo.c

@@ -118,6 +118,9 @@ bi_pick_ubo(struct panfrost_ubo_push *push, struct bi_ubo_analysis *analysis)
 void
 bi_opt_push_ubo(bi_context *ctx)
 {
+        if (ctx->inputs->no_ubo_to_push)
+                return;
+
         /* This pass only runs once */
         assert(ctx->info->push.count == 0);
 

src/panfrost/midgard/mir_promote_uniforms.c

@@ -258,6 +258,9 @@ mir_special_indices(compiler_context *ctx)
 void
 midgard_promote_uniforms(compiler_context *ctx)
 {
+        if (ctx->inputs->no_ubo_to_push)
+                return;
+
         struct mir_ubo_analysis analysis = mir_analyze_ranges(ctx);
 
         unsigned work_count = mir_work_heuristic(ctx, &analysis);

src/panfrost/util/pan_ir.h

@@ -126,6 +126,7 @@ struct panfrost_compile_inputs {
                 uint64_t bifrost_blend_desc;
         } blend;
         bool shaderdb;
+        bool no_ubo_to_push;
 
         enum pipe_format rt_formats[8];
 };