Single Compilation Unit build.

Adds support for simple SCU build (DEV_ENABLED only).
This speeds up compilation by compiling multiple cpp files within a single translation unit.

1 files changed, 339 insertions, 0 deletions

diff --git a/scu_builders.py b/scu_builders.py
new file mode 100644
index 0000000000..98363929ae
--- /dev/null
+++ b/scu_builders.py
@@ -0,0 +1,339 @@
+"""Functions used to generate scu build source files during build time
+"""
+import glob, os
+import math
+from pathlib import Path
+from os.path import normpath, basename
+
+base_folder_path = str(Path(__file__).parent) + "/"
+base_folder_only = os.path.basename(os.path.normpath(base_folder_path))
+_verbose = False
+_is_release_build = False
+_scu_folders = set()
+
+
+def clear_out_existing_files(output_folder, extension):
+    output_folder = os.path.abspath(output_folder)
+    # print("clear_out_existing_files from folder: " + output_folder)
+
+    if not os.path.isdir(output_folder):
+        # folder does not exist or has not been created yet,
+        # no files to clearout. (this is not an error)
+        return
+
+    for file in glob.glob(output_folder + "/*." + extension):
+        # print("removed pre-existing file: " + file)
+        os.remove(file)
+
+
+def folder_not_found(folder):
+    abs_folder = base_folder_path + folder + "/"
+    return not os.path.isdir(abs_folder)
+
+
+def find_files_in_folder(folder, sub_folder, include_list, extension, sought_exceptions, found_exceptions):
+    abs_folder = base_folder_path + folder + "/" + sub_folder
+
+    if not os.path.isdir(abs_folder):
+        print("ERROR " + abs_folder + " not found.")
+        return include_list, found_exceptions
+
+    os.chdir(abs_folder)
+
+    sub_folder_slashed = ""
+    if sub_folder != "":
+        sub_folder_slashed = sub_folder + "/"
+
+    for file in glob.glob("*." + extension):
+
+        simple_name = Path(file).stem
+
+        if file.endswith(".gen.cpp"):
+            continue
+
+        li = '#include "../' + sub_folder_slashed + file + '"'
+
+        if not simple_name in sought_exceptions:
+            include_list.append(li)
+        else:
+            found_exceptions.append(li)
+
+    return include_list, found_exceptions
+
+
+def write_output_file(file_count, include_list, start_line, end_line, output_folder, output_filename_prefix, extension):
+
+    output_folder = os.path.abspath(output_folder)
+
+    if not os.path.isdir(output_folder):
+        # create
+        os.mkdir(output_folder)
+        if not os.path.isdir(output_folder):
+            print("ERROR " + output_folder + " could not be created.")
+            return
+        print("CREATING folder " + output_folder)
+
+    file_text = ""
+
+    for l in range(start_line, end_line):
+        if l < len(include_list):
+            line = include_list[l]
+            li = line + "\n"
+            file_text += li
+
+    # print(file_text)
+
+    num_string = ""
+    if file_count > 0:
+        num_string = "_" + str(file_count)
+
+    short_filename = output_filename_prefix + num_string + ".gen." + extension
+    output_filename = output_folder + "/" + short_filename
+    if _verbose:
+        print("generating: " + short_filename)
+
+    output_path = Path(output_filename)
+    output_path.write_text(file_text, encoding="utf8")
+
+
+def write_exception_output_file(file_count, exception_string, output_folder, output_filename_prefix, extension):
+    output_folder = os.path.abspath(output_folder)
+    if not os.path.isdir(output_folder):
+        print("ERROR " + output_folder + " does not exist.")
+        return
+
+    file_text = exception_string + "\n"
+
+    num_string = ""
+    if file_count > 0:
+        num_string = "_" + str(file_count)
+
+    short_filename = output_filename_prefix + "_exception" + num_string + ".gen." + extension
+    output_filename = output_folder + "/" + short_filename
+
+    if _verbose:
+        print("generating: " + short_filename)
+
+    # print("text: " + file_text)
+    # return
+    output_path = Path(output_filename)
+    output_path.write_text(file_text, encoding="utf8")
+
+
+def find_section_name(sub_folder):
+    # Construct a useful name for the section from the path for debug logging
+    section_path = os.path.abspath(base_folder_path + sub_folder) + "/"
+
+    folders = []
+    folder = ""
+
+    for i in range(8):
+        folder = os.path.dirname(section_path)
+        folder = os.path.basename(folder)
+        if folder == base_folder_only:
+            break
+        folders.append(folder)
+        section_path += "../"
+        section_path = os.path.abspath(section_path) + "/"
+
+    section_name = ""
+    for n in range(len(folders)):
+        section_name += folders[len(folders) - n - 1]
+        if n != (len(folders) - 1):
+            section_name += "_"
+
+    return section_name
+
+
+# "folders" is a list of folders to add all the files from to add to the SCU
+# "section (like a module)". The name of the scu file will be derived from the first folder
+# (thus e.g. scene/3d becomes scu_scene_3d.gen.cpp)
+
+# "includes_per_scu" limits the number of includes in a single scu file.
+# This allows the module to be built in several translation units instead of just 1.
+# This will usually be slower to compile but will use less memory per compiler instance, which
+# is most relevant in release builds.
+
+# "sought_exceptions" are a list of files (without extension) that contain
+# e.g. naming conflicts, and are therefore not suitable for the scu build.
+# These will automatically be placed in their own separate scu file,
+# which is slow like a normal build, but prevents the naming conflicts.
+# Ideally in these situations, the source code should be changed to prevent naming conflicts.
+
+# "extension" will usually be cpp, but can also be set to c (for e.g. third party libraries that use c)
+def process_folder(folders, sought_exceptions=[], includes_per_scu=0, extension="cpp"):
+    if len(folders) == 0:
+        return
+
+    # Construct the filename prefix from the FIRST folder name
+    # e.g. "scene_3d"
+    out_filename = find_section_name(folders[0])
+
+    found_includes = []
+    found_exceptions = []
+
+    main_folder = folders[0]
+    abs_main_folder = base_folder_path + main_folder
+
+    # Keep a record of all folders that have been processed for SCU,
+    # this enables deciding what to do when we call "add_source_files()"
+    global _scu_folders
+    _scu_folders.add(main_folder)
+
+    # main folder (first)
+    found_includes, found_exceptions = find_files_in_folder(
+        main_folder, "", found_includes, extension, sought_exceptions, found_exceptions
+    )
+
+    # sub folders
+    for d in range(1, len(folders)):
+        found_includes, found_exceptions = find_files_in_folder(
+            main_folder, folders[d], found_includes, extension, sought_exceptions, found_exceptions
+        )
+
+    found_includes = sorted(found_includes)
+
+    # calculate how many lines to write in each file
+    total_lines = len(found_includes)
+
+    # adjust number of output files according to whether DEV or release
+    num_output_files = 1
+    if _is_release_build:
+        # always have a maximum in release
+        includes_per_scu = 8
+        num_output_files = max(math.ceil(total_lines / float(includes_per_scu)), 1)
+    else:
+        if includes_per_scu > 0:
+            num_output_files = max(math.ceil(total_lines / float(includes_per_scu)), 1)
+
+    lines_per_file = math.ceil(total_lines / float(num_output_files))
+    lines_per_file = max(lines_per_file, 1)
+
+    start_line = 0
+    file_number = 0
+
+    # These do not vary throughout the loop
+    output_folder = abs_main_folder + "/scu/"
+    output_filename_prefix = "scu_" + out_filename
+
+    # Clear out any existing files (usually we will be overwriting,
+    # but we want to remove any that are pre-existing that will not be
+    # overwritten, so as to not compile anything stale)
+    clear_out_existing_files(output_folder, extension)
+
+    for file_count in range(0, num_output_files):
+        end_line = start_line + lines_per_file
+
+        # special case to cover rounding error in final file
+        if file_count == (num_output_files - 1):
+            end_line = len(found_includes)
+
+        write_output_file(
+            file_count, found_includes, start_line, end_line, output_folder, output_filename_prefix, extension
+        )
+
+        start_line = end_line
+
+    # Write the exceptions each in their own scu gen file,
+    # so they can effectively compile in "old style / normal build".
+    for exception_count in range(len(found_exceptions)):
+        write_exception_output_file(
+            exception_count, found_exceptions[exception_count], output_folder, output_filename_prefix, extension
+        )
+
+
+def generate_scu_files(verbose, is_release_build):
+
+    print("=============================")
+    print("Single Compilation Unit Build")
+    print("=============================")
+    print("Generating SCU build files")
+    global _verbose
+    _verbose = verbose
+    global _is_release_build
+    _is_release_build = is_release_build
+
+    curr_folder = os.path.abspath("./")
+
+    # check we are running from the correct folder
+    if folder_not_found("core") or folder_not_found("platform") or folder_not_found("scene"):
+        raise RuntimeError("scu_builders.py must be run from the godot folder.")
+        return
+
+    process_folder(["core"])
+    process_folder(["core/crypto"])
+    process_folder(["core/debugger"])
+    process_folder(["core/extension"])
+    process_folder(["core/input"])
+    process_folder(["core/io"])
+    process_folder(["core/math"])
+    process_folder(["core/object"])
+    process_folder(["core/os"])
+    process_folder(["core/string"])
+    process_folder(["core/variant"], ["variant_utility"])
+
+    process_folder(["drivers/unix"])
+    process_folder(["drivers/png"])
+
+    process_folder(["editor"], ["file_system_dock", "editor_resource_preview"], 32)
+    process_folder(["editor/debugger"])
+    process_folder(["editor/debugger/debug_adapter"])
+    process_folder(["editor/export"])
+    process_folder(["editor/gui"])
+    process_folder(["editor/import"])
+    process_folder(["editor/plugins"])
+    process_folder(["editor/plugins/gizmos"])
+    process_folder(["editor/plugins/tiles"])
+
+    process_folder(["platform/android/export"])
+    process_folder(["platform/ios/export"])
+    process_folder(["platform/linuxbsd/export"])
+    process_folder(["platform/macos/export"])
+    process_folder(["platform/uwp/export"])
+    process_folder(["platform/web/export"])
+    process_folder(["platform/windows/export"])
+
+    process_folder(["modules/gltf"])
+    process_folder(["modules/gltf/structures"])
+    process_folder(["modules/gltf/editor"])
+    process_folder(["modules/gltf/extensions"])
+    process_folder(["modules/gltf/extensions/physics"])
+    process_folder(["modules/navigation"])
+    process_folder(["modules/webrtc"])
+    process_folder(["modules/websocket"])
+    process_folder(["modules/gridmap"])
+    process_folder(["modules/multiplayer"])
+    process_folder(["modules/multiplayer/editor"])
+    process_folder(["modules/openxr"], ["register_types"])
+    process_folder(["modules/openxr/action_map"])
+    process_folder(["modules/openxr/editor"])
+
+    process_folder(["modules/csg"])
+    process_folder(["modules/gdscript"])
+    process_folder(["modules/gdscript/editor"])
+    process_folder(["modules/gdscript/language_server"])
+
+    process_folder(["scene/2d"])
+    process_folder(["scene/3d"])
+    process_folder(["scene/animation"])
+    process_folder(["scene/gui"])
+    process_folder(["scene/main"])
+    process_folder(["scene/resources"])
+
+    process_folder(["servers"])
+    process_folder(["servers/rendering"])
+    process_folder(["servers/rendering/storage"])
+    process_folder(["servers/rendering/renderer_rd"])
+    process_folder(["servers/rendering/renderer_rd/effects"])
+    process_folder(["servers/rendering/renderer_rd/environment"])
+    process_folder(["servers/rendering/renderer_rd/storage_rd"])
+    process_folder(["servers/physics_2d"])
+    process_folder(["servers/physics_3d"])
+    process_folder(["servers/physics_3d/joints"])
+    process_folder(["servers/audio"])
+    process_folder(["servers/audio/effects"])
+
+    # Finally change back the path to the calling folder
+    os.chdir(curr_folder)
+
+    return _scu_folders