Make LTO an option in gen.py
Previously, LTO was enabled unconditionally for all release builds
but this was causing issues and got reverted in
https://gn-review.googlesource.com/2120, but LTO still makes sense
for release builds where we control the compiler, so we make it an
option which can be enabled as needed.
Change-Id: I4650210a326aeeb00a44d853b8b2da0c90ef17a5
Reviewed-on: https://gn-review.googlesource.com/2200
Reviewed-by: Brett Wilson <brettw@chromium.org>
Commit-Queue: Brett Wilson <brettw@chromium.org>
diff --git a/build/gen.py b/build/gen.py
index 9dda914..fe16882 100755
--- a/build/gen.py
+++ b/build/gen.py
@@ -31,6 +31,8 @@
parser = optparse.OptionParser(description=sys.modules[__name__].__doc__)
parser.add_option('-d', '--debug', action='store_true',
help='Do a debug build. Defaults to release build.')
+ parser.add_option('--use-lto', action='store_true',
+ help='Enable the use of LTO')
parser.add_option('--no-sysroot', action='store_true',
help='(Linux only) Do not build with the Debian sysroot.')
parser.add_option('--no-last-commit-position', action='store_true',
@@ -291,6 +293,10 @@
cflags.append(min_mac_version_flag)
ldflags.append(min_mac_version_flag)
+ if options.use_lto:
+ cflags.extend(['-flto', '-fwhole-program-vtables'])
+ ldflags.extend(['-flto', '-fwhole-program-vtables'])
+
elif is_win:
if not options.debug:
cflags.extend(['/Ox', '/DNDEBUG', '/GL'])
