dlist: use an union instead of allocating a 1-sized array

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11493>

diff --git a/src/mesa/main/dlist.c b/src/mesa/main/dlist.c
index d86fcbb..b43b383 100644 (file)
--- a/src/mesa/main/dlist.c
+++ b/src/mesa/main/dlist.c
@@ -800,8 +800,10 @@ vbo_destroy_vertex_list(struct gl_context *ctx, struct vbo_save_vertex_list *nod
       free(node->prim_store);
    }
 
-   free(node->merged.mode);
-   free(node->merged.start_count);
+   if (node->merged.mode) {
+      free(node->merged.mode);
+      free(node->merged.start_counts);
+   }
 
    _mesa_reference_buffer_object(ctx, &node->merged.ib.obj, NULL);
    free(node->current_data);

diff --git a/src/mesa/vbo/vbo_save.h b/src/mesa/vbo/vbo_save.h
index 0a0eaeb..ca592a3 100644 (file)
--- a/src/mesa/vbo/vbo_save.h
+++ b/src/mesa/vbo/vbo_save.h
@@ -72,7 +72,10 @@ struct vbo_save_vertex_list {
       struct _mesa_index_buffer ib;
       struct pipe_draw_info info;
       unsigned char *mode;
-      struct pipe_draw_start_count_bias *start_count;
+      union {
+         struct pipe_draw_start_count_bias *start_counts;
+         struct pipe_draw_start_count_bias start_count;
+      };
       unsigned num_draws;
    } merged;
 

diff --git a/src/mesa/vbo/vbo_save_api.c b/src/mesa/vbo/vbo_save_api.c
index e69f543..ed8d529 100644 (file)
--- a/src/mesa/vbo/vbo_save_api.c
+++ b/src/mesa/vbo/vbo_save_api.c
@@ -809,20 +809,21 @@ compile_vertex_list(struct gl_context *ctx)
    node->merged.info.index_size = 4;
    node->merged.info.instance_count = 1;
    node->merged.info.index.gl_bo = node->merged.ib.obj;
-   node->merged.start_count = malloc(merged_prim_count * sizeof(struct pipe_draw_start_count_bias));
    if (merged_prim_count == 1) {
       node->merged.info.mode = merged_prims[0].mode;
+      node->merged.start_count.start = merged_prims[0].start;
+      node->merged.start_count.count = merged_prims[0].count;
+      node->merged.start_count.index_bias = 0;
       node->merged.mode = NULL;
    } else {
       node->merged.mode = malloc(merged_prim_count * sizeof(unsigned char));
-   }
-
-   for (unsigned i = 0; i < merged_prim_count; i++) {
-      node->merged.start_count[i].start = merged_prims[i].start;
-      node->merged.start_count[i].count = merged_prims[i].count;
-      node->merged.start_count[i].index_bias = 0;
-      if (merged_prim_count > 1)
+      node->merged.start_counts = malloc(merged_prim_count * sizeof(struct pipe_draw_start_count_bias));
+      for (unsigned i = 0; i < merged_prim_count; i++) {
+         node->merged.start_counts[i].start = merged_prims[i].start;
+         node->merged.start_counts[i].count = merged_prims[i].count;
+         node->merged.start_counts[i].index_bias = 0;
          node->merged.mode[i] = merged_prims[i].mode;
+      }
    }
    node->merged.num_draws = merged_prim_count;
    if (node->merged.num_draws > 1) {

diff --git a/src/mesa/vbo/vbo_save_draw.c b/src/mesa/vbo/vbo_save_draw.c
index 330a3a8..104b0bf 100644 (file)
--- a/src/mesa/vbo/vbo_save_draw.c
+++ b/src/mesa/vbo/vbo_save_draw.c
@@ -232,14 +232,15 @@ vbo_save_playback_vertex_list(struct gl_context *ctx, void *data)
       info->vertices_per_patch = ctx->TessCtrlProgram.patch_vertices;
       void *gl_bo = info->index.gl_bo;
       if (node->merged.mode) {
+         assert(node->merged.mode);
          ctx->Driver.DrawGalliumMultiMode(ctx, info, 0,
-                                        node->merged.start_count,
-                                        node->merged.mode,
-                                        node->merged.num_draws);
+                                          node->merged.start_counts,
+                                          node->merged.mode,
+                                          node->merged.num_draws);
       } else if (node->merged.num_draws) {
-         ctx->Driver.DrawGallium(ctx, info, 0,
-                                 node->merged.start_count,
-                                 node->merged.num_draws);
+         /* If node->merged.mode is NULL then num_draws is 0 or 1 */
+         assert (node->merged.num_draws == 1);
+         ctx->Driver.DrawGallium(ctx, info, 0, &node->merged.start_count, 1);
       }
       info->index.gl_bo = gl_bo;
    }