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From 2f2028a19fd12477fcd9050ea354174f33b68b46 Mon Sep 17 00:00:00 2001
From: Elvis Pranskevichus <elvis@magic.io>
Date: Mon, 21 Aug 2017 10:16:44 -0400
Subject: [PATCH] LTO fixes
---
build/config/compiler/BUILD.gn | 35 +++++++++++++++++++++++++----------
build/config/posix/BUILD.gn | 2 +-
build/toolchain/gcc_ar_wrapper.py | 12 +++++++++++-
3 files changed, 37 insertions(+), 12 deletions(-)
diff --git a/build/config/compiler/BUILD.gn b/build/config/compiler/BUILD.gn
index d0510b8..583f186 100644
--- a/build/config/compiler/BUILD.gn
+++ b/build/config/compiler/BUILD.gn
@@ -448,20 +448,35 @@ config("compiler") {
} else {
# Note: ThinLTO does not currently have this feature implemented
# For Full LTO, it provides a measurable runtime speedup of Chrome.
- cflags += [
- "-flto",
- "-fwhole-program-vtables",
- ]
- ldflags += [
- "-flto",
- "-fwhole-program-vtables",
- ]
+ if (is_clang) {
+ cflags += [
+ "-flto",
+ "-fwhole-program-vtables"
+ ]
+ ldflags += [
+ "-flto",
+ "-fwhole-program-vtables"
+ ]
+ } else {
+ cflags += [
+ "-flto=4",
+ "-fno-fat-lto-objects",
+ "-fuse-linker-plugin",
+ "--param=lto-partitions=1",
+ ]
+ ldflags += [
+ "-flto=4",
+ "-fno-fat-lto-objects",
+ "-fuse-linker-plugin",
+ "--param=lto-partitions=1",
+ ]
+ }
# Apply a lower LTO optimization level as the default is too slow.
if (is_linux) {
if (use_lld) {
ldflags += [ "-Wl,--lto-O1" ]
- } else {
+ } else if (is_clang) {
ldflags += [ "-Wl,-plugin-opt,O1" ]
}
} else if (is_mac) {
@@ -478,7 +493,7 @@ config("compiler") {
# targeting ARM, without this flag, LTO produces a .text section that is
# larger than the maximum call displacement, preventing the linker from
# relocating calls (http://llvm.org/PR22999).
- if (is_linux) {
+ if (is_linux && is_clang) {
ldflags += [ "-Wl,-plugin-opt,-function-sections" ]
}
}
diff --git a/build/config/posix/BUILD.gn b/build/config/posix/BUILD.gn
index d7e917a..fc68864 100644
--- a/build/config/posix/BUILD.gn
+++ b/build/config/posix/BUILD.gn
@@ -21,7 +21,7 @@ config("compiler") {
if ((allow_posix_link_time_opt || is_cfi) && !is_nacl) {
arflags = [
"--plugin",
- rebase_path("$clang_base_path/lib/LLVMgold.so", root_build_dir),
+ "auto"
]
}
}
diff --git a/build/toolchain/gcc_ar_wrapper.py b/build/toolchain/gcc_ar_wrapper.py
index de53df0..39c7b56 100755
--- a/build/toolchain/gcc_ar_wrapper.py
+++ b/build/toolchain/gcc_ar_wrapper.py
@@ -47,7 +47,17 @@ def main():
command = [args.ar, args.operation]
if args.plugin is not None:
- command += ['--plugin', args.plugin]
+ if args.plugin == 'auto':
+ gcc = os.environ.get('CC', '/usr/bin/cc')
+ gcc_ver = subprocess.check_output([gcc, '-dumpversion'],
+ universal_newlines=True)
+ gcc_ver = gcc_ver.strip(' \n')
+ plugin = '/usr/libexec/gcc/x86_64-pc-linux-gnu/{}/liblto_plugin.so'. \
+ format(gcc_ver)
+ else:
+ plugin = args.plugin
+
+ command += ['--plugin', plugin]
command.append(args.output)
command += args.inputs
--
2.14.1
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