wip(workgraph): use node name in function signature

Author: buggy213

include/luisa/dsl/work_graph/work_graph.h

@@ -92,6 +92,7 @@ class WorkGraphNode {
 
         // yoink the function builder, make sure type of input record matches what we were declared with
         inner()->fn_builder = kernel.function_builder();
+        inner()->fn_builder->set_name(inner()->name);
         inner()->defined = true;
     }
 

src/backends/common/hlsl/codegen_utils/work_graph_codegen.cpp

@@ -294,6 +294,8 @@ void CodegenUtility::CodegenWorkGraphNode(const WorkGraph &work_graph, size_t no
     GenerateNodeShaderAttributes(is_entry_point, node.name, result);
 
     // Generate node function signature
+    // use actual name from frontend here, rather than custom_<i>, since node names are meaningful
+    LUISA_ASSERT(!node_func.name().empty(), "work graph node's FunctionBuilder has invalid name");
     result << "void "sv << node_func.name() << "(\n"sv;
 
     // Generate node function parameters using helper

src/dsl/work_graph/work_graph.cpp

@@ -59,6 +59,7 @@ LUISA_DSL_API WorkGraph WorkGraphBuilder::build() noexcept {
     luisa::unordered_set<luisa::string_view> node_names;
     for (auto const& node : _nodes) {
         auto [_, name_unique] = node_names.insert(node.name);
+        LUISA_ASSERT(!node.name.empty(), "names of work graph nodes cannot be empty");
         LUISA_ASSERT(name_unique, "names of work graph nodes must be unique");
     }