Geometry Nodes: deterministic anonymous attribute lifetimes

Previously, the lifetimes of anonymous attributes were determined by
reference counts which were non-deterministic when multiple threads
are used. Now the lifetimes of anonymous attributes are handled
more explicitly and deterministically. This is a prerequisite for any kind
of caching, because caching the output of nodes that do things
non-deterministically and have "invisible inputs" (reference counts)
doesn't really work.

For more details for how deterministic lifetimes are achieved, see D16858.

No functional changes are expected. Small performance changes are expected
as well (within few percent, anything larger regressions should be reported as
bugs).

Differential Revision: https://developer.blender.org/D16858

source/blender/blenkernel/BKE_node_runtime.hh

@@ -7,6 +7,7 @@
 
 #include "BLI_cache_mutex.hh"
 #include "BLI_multi_value_map.hh"
+#include "BLI_resource_scope.hh"
 #include "BLI_utility_mixins.hh"
 #include "BLI_vector.hh"
 #include "BLI_vector_set.hh"
@@ -24,6 +25,10 @@ namespace blender::nodes {
 struct FieldInferencingInterface;
 class NodeDeclaration;
 struct GeometryNodesLazyFunctionGraphInfo;
+namespace anonymous_attribute_lifetime {
+struct RelationsInNode;
+}
+namespace aal = anonymous_attribute_lifetime;
 }  // namespace blender::nodes
 
 namespace blender {
@@ -106,6 +111,8 @@ class bNodeTreeRuntime : NonCopyable, NonMovable {
 
   /** Information about how inputs and outputs of the node group interact with fields. */
   std::unique_ptr<nodes::FieldInferencingInterface> field_inferencing_interface;
+  /** Information about usage of anonymous attributes within the group. */
+  std::unique_ptr<nodes::aal::RelationsInNode> anonymous_attribute_relations;
 
   /**
    * For geometry nodes, a lazy function graph with some additional info is cached. This is used to
@@ -330,7 +337,11 @@ inline bool topology_cache_is_available(const bNodeSocket &socket)
 namespace node_field_inferencing {
 bool update_field_inferencing(const bNodeTree &tree);
 }
-
+namespace anonymous_attribute_inferencing {
+Array<const nodes::aal::RelationsInNode *> get_relations_by_node(const bNodeTree &tree,
+                                                                 ResourceScope &scope);
+bool update_anonymous_attribute_relations(bNodeTree &tree);
+}  // namespace anonymous_attribute_inferencing
 }  // namespace blender::bke
 
 /* -------------------------------------------------------------------- */