SCons: Add 'split_libmodules' option to workaround linker issue

The new 'split_libmodules=yes' option is useful to work around linker
command line size limitations when linking a huge number of objects.
We're currently over 64k chars when linking libmodules.a on Windows
with MinGW, which triggers issues as seen in #30892.

Even on Linux, we can also reach linker command line size limitations
by adding more custom modules.

We force this option to True for MinGW on Windows, which fixes #30892.

Additional changes to lib splitting:

- Fix linking of the split module libs with interdependent symbols,
  hacking our way into LINKCOM and SHLINKCOM to set the `--start-group`
  and `--end-group` flags.
- Fix Python 3 compatibility in `methods.split_lib()`.
- Drop seemingly obsolete condition for 'msys' on 'posix'.
- Drop the unnecessary 'split_drivers' as the drivers lib is no longer
  too big since we moved all thirdparty builds to modules.

Co-authored-by: Hein-Pieter van Braam-Stewart <hp@tmm.cx>
This commit is contained in:
Rémi Verschelde 2019-12-09 19:22:08 +01:00
parent cd9d513285
commit c320a82213
5 changed files with 31 additions and 19 deletions

View File

@ -68,8 +68,6 @@ env_base.AppendENVPath('PATH', os.getenv('PATH'))
env_base.AppendENVPath('PKG_CONFIG_PATH', os.getenv('PKG_CONFIG_PATH'))
env_base.disabled_modules = []
env_base.use_ptrcall = False
env_base.split_drivers = False
env_base.split_modules = False
env_base.module_version_string = ""
env_base.msvc = False
@ -129,6 +127,7 @@ opts.Add(BoolVariable('dev', "If yes, alias for verbose=yes warnings=extra werro
opts.Add('extra_suffix', "Custom extra suffix added to the base filename of all generated binary files", '')
opts.Add(BoolVariable('vsproj', "Generate a Visual Studio solution", False))
opts.Add(EnumVariable('macports_clang', "Build using Clang from MacPorts", 'no', ('no', '5.0', 'devel')))
opts.Add(BoolVariable('split_libmodules', "Split intermediate libmodules.a in smaller chunks to prevent exceeding linker command line size (forced to True when using MinGW)", False))
opts.Add(BoolVariable('disable_3d', "Disable 3D nodes for a smaller executable", False))
opts.Add(BoolVariable('disable_advanced_gui', "Disable advanced GUI nodes and behaviors", False))
opts.Add(BoolVariable('no_editor_splash', "Don't use the custom splash screen for the editor", False))

View File

@ -46,9 +46,7 @@ if env['vsproj']:
env.AddToVSProject(env.drivers_sources)
os.chdir(path)
if env.split_drivers:
env.split_lib("drivers")
else:
env.add_source_files(env.drivers_sources, "*.cpp")
lib = env.add_library("drivers", env.drivers_sources)
env.Prepend(LIBS=[lib])
env.add_source_files(env.drivers_sources, "*.cpp")
lib = env.add_library("drivers", env.drivers_sources)
env.Prepend(LIBS=[lib])

View File

@ -307,7 +307,7 @@ def split_lib(self, libname, src_list = None, env_lib = None):
else:
fname = env.File(f)[0].path
fname = fname.replace("\\", "/")
base = string.join(fname.split("/")[:2], "/")
base = "/".join(fname.split("/")[:2])
if base != cur_base and len(list) > max_src:
if num > 0:
lib = env_lib.add_library(libname + str(num), list)
@ -320,12 +320,6 @@ def split_lib(self, libname, src_list = None, env_lib = None):
lib = env_lib.add_library(libname + str(num), list)
lib_list.append(lib)
if len(lib_list) > 0:
if os.name == 'posix' and sys.platform == 'msys':
env.Replace(ARFLAGS=['rcsT'])
lib = env_lib.add_library(libname + "_collated", lib_list)
lib_list = [lib]
lib_base = []
env_lib.add_source_files(lib_base, "*.cpp")
lib = env_lib.add_library(libname, lib_base)
@ -333,6 +327,24 @@ def split_lib(self, libname, src_list = None, env_lib = None):
env.Prepend(LIBS=lib_list)
# When we split modules into arbitrary chunks, we end up with linking issues
# due to symbol dependencies split over several libs, which may not be linked
# in the required order. We use --start-group and --end-group to tell the
# linker that those archives should be searched repeatedly to resolve all
# undefined references.
# As SCons doesn't give us much control over how inserting libs in LIBS
# impacts the linker call, we need to hack our way into the linking commands
# LINKCOM and SHLINKCOM to set those flags.
if '-Wl,--start-group' in env['LINKCOM'] and '-Wl,--start-group' in env['SHLINKCOM']:
# Already added by a previous call, skip.
return
env['LINKCOM'] = str(env['LINKCOM']).replace('$_LIBFLAGS',
'-Wl,--start-group $_LIBFLAGS -Wl,--end-group')
env['SHLINKCOM'] = str(env['LINKCOM']).replace('$_LIBFLAGS',
'-Wl,--start-group $_LIBFLAGS -Wl,--end-group')
def save_active_platforms(apnames, ap):

View File

@ -16,7 +16,7 @@ for x in env.module_list:
env_modules.Append(CPPDEFINES=["MODULE_" + x.upper() + "_ENABLED"])
SConscript(x + "/SCsub")
if env.split_modules:
if env['split_libmodules']:
env.split_lib("modules", env_lib = env_modules)
else:
lib = env_modules.add_library("modules", env.modules_sources)

View File

@ -151,14 +151,14 @@ def setup_msvc_auto(env):
env['bits'] = '64'
else:
env['bits'] = '32'
print(" Found MSVC version %s, arch %s, bits=%s" % (env['MSVC_VERSION'], env['TARGET_ARCH'], env['bits']))
print("Found MSVC version %s, arch %s, bits=%s" % (env['MSVC_VERSION'], env['TARGET_ARCH'], env['bits']))
if env['TARGET_ARCH'] in ('amd64', 'x86_64'):
env["x86_libtheora_opt_vc"] = False
def setup_mingw(env):
"""Set up env for use with mingw"""
# Nothing to do here
print("Using Mingw")
print("Using MinGW")
pass
def configure_msvc(env, manual_msvc_config):
@ -294,7 +294,10 @@ def configure_mingw(env):
## Compiler configuration
if (os.name == "nt"):
env['ENV']['TMP'] = os.environ['TMP'] # way to go scons, you can be so stupid sometimes
# Force splitting libmodules.a in multiple chunks to work around
# issues reaching the linker command line size limit, which also
# seem to induce huge slowdown for 'ar' (GH-30892).
env['split_libmodules'] = True
else:
env["PROGSUFFIX"] = env["PROGSUFFIX"] + ".exe" # for linux cross-compilation