[Reflection] Major rework for much faster compile-times

.bazelrc

@@ -1,5 +1,6 @@
 ### CXX_FLAGS
 build --per_file_copt external/.*@-g0,-O3,-fno-sanitize=all,-fexceptions
+build:clang --define=using_clang=true
 build:clang --per_file_copt external/.*@-Wno-everything,-ftrivial-auto-var-init=uninitialized
 build --copt -Werror
 build --copt -fno-exceptions

BUILD.bazel

@@ -18,6 +18,11 @@ config_setting(
     define_values = {"enable_strip_include_prefix_instead_of_includes": "true"},
 )
 
+config_setting(
+    name = "is_clang_build",
+    define_values = {"using_clang": "true"},
+)
+
 cc_library(
     name = "algorithm",
     hdrs = ["include/fixed_containers/algorithm.hpp"],
@@ -857,7 +862,8 @@ cc_library(
         ":fixed_stack",
         ":fixed_vector",
         ":in_out",
-        ":tuples",
+        ":struct_decomposition",
+        ":variadic_templates",
     ],
     copts = ["-std=c++20"],
 )
@@ -918,6 +924,22 @@ cc_library(
     copts = ["-std=c++20"],
 )
 
+cc_library(
+    name = "struct_decomposition",
+    hdrs = [
+        "include/fixed_containers/struct_decomposition.hpp",
+        "include/fixed_containers/struct_decomposition_129_to_512.hpp",
+        "include/fixed_containers/struct_decomposition_513_to_768.hpp",
+        "include/fixed_containers/struct_decomposition_769_to_1024.hpp",
+    ],
+    includes = includes_config(),
+    strip_include_prefix = strip_include_prefix_config(),
+    deps = [
+        ":concepts",
+    ],
+    copts = ["-std=c++20"],
+)
+
 cc_library(
     name = "struct_view",
     hdrs = ["include/fixed_containers/struct_view.hpp"],
@@ -947,10 +969,7 @@ cc_library(
 
 cc_library(
     name = "tuples",
-    hdrs = [
-        "include/fixed_containers/tuples.hpp",
-        "include/fixed_containers/tuples_as_tuple_view.hpp"
-    ],
+    hdrs = ["include/fixed_containers/tuples.hpp"],
     includes = includes_config(),
     strip_include_prefix = strip_include_prefix_config(),
     deps = [
@@ -979,6 +998,14 @@ cc_library(
     copts = ["-std=c++20"],
 )
 
+cc_library(
+    name = "variadic_templates",
+    hdrs = ["include/fixed_containers/variadic_templates.hpp"],
+    includes = includes_config(),
+    strip_include_prefix = strip_include_prefix_config(),
+    copts = ["-std=c++20"],
+)
+
 cc_library(
     name = "enums_test_common",
     hdrs = ["test/enums_test_common.hpp"],
@@ -1705,6 +1732,21 @@ cc_test(
     copts = ["-std=c++20"],
 )
 
+cc_test(
+    name = "reflection_big_struct_test",
+    srcs = ["test/reflection_big_struct_test.cpp"],
+    deps = [
+        ":reflection",
+        "@com_google_googletest//:gtest",
+        "@com_google_googletest//:gtest_main",
+    ],
+    copts = ["-std=c++20"] +
+        select({
+        "//conditions:default": [],
+        ":is_clang_build": ["-fbracket-depth=1024"],
+    }),
+)
+
 cc_test(
     name = "reflection_test",
     srcs = ["test/reflection_test.cpp"],
@@ -1743,6 +1785,18 @@ cc_test(
     copts = ["-std=c++20"],
 )
 
+cc_test(
+    name = "struct_decomposition_codegen",
+    srcs = ["test/struct_decomposition_codegen.cpp"],
+    deps = [
+        ":fixed_string",
+        ":fixed_vector",
+        ":int_math",
+        ":struct_decomposition",
+    ],
+    copts = ["-std=c++20"],
+)
+
 cc_test(
     name = "struct_view_test",
     srcs = ["test/struct_view_test.cpp"],

CMakeLists.txt

@@ -223,18 +223,28 @@ if(BUILD_TESTS)
     add_test_dependencies(pair_view_test)
     add_executable(queue_adapter_test test/queue_adapter_test.cpp)
     add_test_dependencies(queue_adapter_test)
+    add_executable(reflection_big_struct_test test/reflection_big_struct_test.cpp)
+    add_test_dependencies(reflection_big_struct_test)
     add_executable(reflection_test test/reflection_test.cpp)
     add_test_dependencies(reflection_test)
     add_executable(stack_adapter_test test/stack_adapter_test.cpp)
     add_test_dependencies(stack_adapter_test)
     add_executable(string_literal_test test/string_literal_test.cpp)
     add_test_dependencies(string_literal_test)
+    add_executable(struct_decomposition_codegen test/struct_decomposition_codegen.cpp)
+    add_test_dependencies(struct_decomposition_codegen)
     add_executable(struct_view_test test/struct_view_test.cpp)
     add_test_dependencies(struct_view_test)
     add_executable(tuples_test test/tuples_test.cpp)
     add_test_dependencies(tuples_test)
     add_executable(type_name_test test/type_name_test.cpp)
     add_test_dependencies(type_name_test)
+    add_executable(variadic_templates_test test/variadic_templates_test.cpp)
+    add_test_dependencies(variadic_templates_test)
+
+    if(${USING_CLANG})
+        target_compile_options(reflection_big_struct_test PRIVATE -fbracket-depth=1024)
+    endif()
 endif()
 
 option(FIXED_CONTAINERS_OPT_INSTALL "Enable install target" ${PROJECT_IS_TOP_LEVEL})

README.md

@@ -423,6 +423,13 @@ CC=g++-11 bazel build --config=gcc ...
 CC=g++-11 bazel test --config=gcc :all_tests
 ```
 
+### clang-tidy
+Run with:
+```
+run-clang-tidy -p . -extra-arg-before="-DFIXED_CONTAINERS_CLANG_TIDY_RUNNING"
+```
+The macro is needed to avoid analysis on some particularly slow places.
+
 ## Tested Compilers
 
 - Clang  13

include/fixed_containers/fixed_map_raw_view.hpp

@@ -21,11 +21,10 @@ class FixedMapRawView
     class Iterator
     {
     public:
-
         // I use Entry so we can match UnorderedMapRawView's API where,
         // *it returns an object with .key() and .value() methods.
-        class Entry {
-
+        class Entry
+        {
         private:
             FixedRedBlackTreeRawView::Iterator base_iterator_;
             std::size_t value_offset_;
@@ -38,24 +37,25 @@ class FixedMapRawView
                   std::size_t max_size_bytes,
                   Compactness compactness,
                   StorageType storage_type,
-                  bool end = false) noexcept:
-                    base_iterator_(ptr,
-                            element_size_bytes,
-                            max_size_bytes,
-                            compactness,
-                            storage_type,
-                            end),
-                    value_offset_(value_offset_bytes) {}
+                  bool end = false) noexcept
+              : base_iterator_(
+                    ptr, element_size_bytes, max_size_bytes, compactness, storage_type, end)
+              , value_offset_(value_offset_bytes)
+            {
+            }
 
-            Entry(): base_iterator_(), value_offset_(0) {}
+            Entry()
+              : base_iterator_()
+              , value_offset_(0)
+            {
+            }
 
             [[nodiscard]] const std::byte* key() const { return *base_iterator_; }
 
             [[nodiscard]] const std::byte* value() const
             {
                 return std::next(*base_iterator_, static_cast<std::ptrdiff_t>(value_offset_));
             }
-
         };
 
     private:
@@ -82,15 +82,19 @@ class FixedMapRawView
                  bool end = false) noexcept
           : entry_(ptr,
                    align_up(key_size_bytes, value_align_bytes),
-                   align_up(align_up(key_size_bytes, value_align_bytes) + value_size_bytes, key_align_bytes),
+                   align_up(align_up(key_size_bytes, value_align_bytes) + value_size_bytes,
+                            key_align_bytes),
                    max_size_bytes,
                    compactness,
                    storage_type,
                    end)
         {
         }
 
-        Iterator() noexcept: entry_() {}
+        Iterator() noexcept
+          : entry_()
+        {
+        }
         Iterator(const Iterator&) noexcept = default;
         Iterator(Iterator&&) noexcept = default;
         Iterator& operator=(const Iterator&) noexcept = default;

include/fixed_containers/fixed_string.hpp

@@ -306,6 +306,13 @@ class FixedString
         null_terminate(loc);
     }
 
+    template <class InputIt>
+    constexpr FixedString& append(
+        const CharT* char_ptr,
+        const std_transition::source_location& loc = std_transition::source_location::current())
+    {
+        return append(std::string_view{char_ptr}, loc);
+    }
     template <class InputIt>
     constexpr FixedString& append(
         InputIt first,
@@ -339,7 +346,7 @@ class FixedString
     }
     constexpr FixedString& operator+=(const CharT* char_ptr)
     {
-        return append(std::string_view{char_ptr}, std_transition::source_location::current());
+        return append(char_ptr, std_transition::source_location::current());
     }
     constexpr FixedString& operator+=(std::initializer_list<CharT> ilist)
     {

include/fixed_containers/reflection.hpp

@@ -5,7 +5,8 @@
 #include "fixed_containers/fixed_stack.hpp"
 #include "fixed_containers/fixed_vector.hpp"
 #include "fixed_containers/in_out.hpp"
-#include "fixed_containers/tuples.hpp"
+#include "fixed_containers/struct_decomposition.hpp"
+#include "fixed_containers/variadic_templates.hpp"
 
 #include <concepts>
 #include <memory>
@@ -240,10 +241,16 @@ template <typename T, typename Func>
 constexpr void for_each_field(T&& instance, Func&& func)
 {
     constexpr const auto& FIELD_NAMES = field_names_of<T>();
-    auto tuple_view = tuples::as_tuple_view<FIELD_NAMES.size()>(instance);
-    tuples::for_each_entry(tuple_view,
-                           [&func]<typename Field>(std::size_t index, Field&& field)
-                           { func(FIELD_NAMES.at(index), std::forward<Field>(field)); });
+    struct_decomposition::to_parameter_pack<FIELD_NAMES.size()>(
+        instance,
+        [&func]<typename... Args>(Args&&... args) -> bool
+        {
+            variadic_templates::for_each_entry(
+                [&]<typename Field>(std::size_t index, Field&& field)
+                { func(FIELD_NAMES.at(index), std::forward<Field>(field)); },
+                std::forward<Args>(args)...);
+            return true;
+        });
 }
 
 }  // namespace fixed_containers::reflection