mesa/st: add 'base_serialized_nir'

this is the pre-finalize nir which has (ideally) not been mangled
by driver-specific lowering passes

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/28189>

src/mesa/main/shader_types.h

@@ -504,6 +504,8 @@ struct gl_program
    GLboolean _Used;        /**< Ever used for drawing? Used for debugging */
 
    struct nir_shader *nir;
+   void *base_serialized_nir;
+   size_t base_serialized_nir_size;
 
    /* Saved and restored with metadata. Freed with ralloc. */
    void *driver_cache_blob;

src/mesa/program/program.c

@@ -251,6 +251,7 @@ _mesa_delete_program(struct gl_context *ctx, struct gl_program *prog)
    st_release_variants(st, prog);
 
    free(prog->serialized_nir);
+   free(prog->base_serialized_nir);
 
    if (prog == &_mesa_DummyProgram)
       return;

src/mesa/state_tracker/st_glsl_to_nir.cpp

@@ -385,8 +385,10 @@ st_glsl_to_nir_post_opts(struct st_context *st, struct gl_program *prog,
    st_finalize_nir_before_variants(nir);
 
    char *msg = NULL;
-   if (st->allow_st_finalize_nir_twice)
+   if (st->allow_st_finalize_nir_twice) {
+      st_serialize_base_nir(prog, nir);
       msg = st_finalize_nir(st, prog, shader_program, nir, true, true);
+   }
 
    if (st->ctx->_Shader->Flags & GLSL_DUMP) {
       _mesa_log("\n");

src/mesa/state_tracker/st_program.c

@@ -390,6 +390,8 @@ st_prog_to_nir_postprocess(struct st_context *st, nir_shader *nir,
    st_finalize_nir_before_variants(nir);
 
    if (st->allow_st_finalize_nir_twice) {
+      st_serialize_base_nir(prog, nir);
+
       char *msg = st_finalize_nir(st, prog, NULL, nir, true, true);
       free(msg);
    }
@@ -560,6 +562,7 @@ st_translate_vertex_program(struct st_context *st,
       free(prog->serialized_nir);
       prog->serialized_nir = NULL;
    }
+   free(prog->base_serialized_nir);
 
    prog->state.type = PIPE_SHADER_IR_NIR;
    if (prog->arb.Instructions)
@@ -1301,6 +1304,20 @@ st_serialize_nir(struct gl_program *prog)
    }
 }
 
+void
+st_serialize_base_nir(struct gl_program *prog, nir_shader *nir)
+{
+   if (!prog->base_serialized_nir && nir->info.stage == MESA_SHADER_VERTEX) {
+      struct blob blob;
+      size_t size;
+
+      blob_init(&blob);
+      nir_serialize(&blob, nir, false);
+      blob_finish_get_buffer(&blob, &prog->base_serialized_nir, &size);
+      prog->base_serialized_nir_size = size;
+   }
+}
+
 void
 st_finalize_program(struct st_context *st, struct gl_program *prog)
 {
@@ -1338,6 +1355,7 @@ st_finalize_program(struct st_context *st, struct gl_program *prog)
        * is disabled. If the disk cache is enabled, GLSL programs are
        * serialized in write_nir_to_cache.
        */
+      st_serialize_base_nir(prog, prog->nir);
       st_serialize_nir(prog);
    }
 

src/mesa/state_tracker/st_program.h

@@ -352,6 +352,8 @@ st_translate_stream_output_info(struct gl_program *prog);
 
 extern void
 st_serialize_nir(struct gl_program *stp);
+void
+st_serialize_base_nir(struct gl_program *prog, struct nir_shader *nir);
 
 extern void
 st_finalize_program(struct st_context *st, struct gl_program *prog);