[llvm] b29573b - [gn build] Support building with ThinLTO
Arthur Eubanks via llvm-commits
llvm-commits at lists.llvm.org
Thu Oct 1 13:49:05 PDT 2020
Author: Arthur Eubanks
Date: 2020-10-01T13:48:31-07:00
New Revision: b29573b672d795dfc58aaf70c70511229584e3c3
URL: https://github.com/llvm/llvm-project/commit/b29573b672d795dfc58aaf70c70511229584e3c3
DIFF: https://github.com/llvm/llvm-project/commit/b29573b672d795dfc58aaf70c70511229584e3c3.diff
LOG: [gn build] Support building with ThinLTO
Differential Revision: https://reviews.llvm.org/D88584
Added:
Modified:
llvm/utils/gn/build/BUILD.gn
llvm/utils/gn/build/buildflags.gni
Removed:
################################################################################
diff --git a/llvm/utils/gn/build/BUILD.gn b/llvm/utils/gn/build/BUILD.gn
index 373d371f017b..f88f4bcc4b6b 100644
--- a/llvm/utils/gn/build/BUILD.gn
+++ b/llvm/utils/gn/build/BUILD.gn
@@ -256,6 +256,27 @@ config("compiler_defaults") {
cflags += [ "-fsanitize=thread" ]
ldflags += [ "-fsanitize=thread" ]
}
+
+ if (use_thinlto) {
+ assert(is_clang, "ThinLTO only supported on Clang")
+
+ lto_opt_level = 2
+
+ cflags += [ "-flto=thin" ]
+
+ if (host_os == "win") {
+ ldflags += [
+ "/opt:lldlto=" + lto_opt_level,
+ "/opt:lldltojobs=" + max_jobs_per_lto_link,
+ ]
+ } else {
+ ldflags += [
+ "-flto=thin",
+ "-Wl,--thinlto-jobs=" + max_jobs_per_lto_link,
+ "-Wl,--lto-O" + lto_opt_level,
+ ]
+ }
+ }
}
config("no_exceptions") {
diff --git a/llvm/utils/gn/build/buildflags.gni b/llvm/utils/gn/build/buildflags.gni
index b04eae19a784..9ad494a3c1e9 100644
--- a/llvm/utils/gn/build/buildflags.gni
+++ b/llvm/utils/gn/build/buildflags.gni
@@ -10,16 +10,22 @@ declare_args() {
# Whether to build with asan.
use_asan = false
-}
-
-# args that depend on other args must live in a later declare_args() block.
-declare_args() {
- # Whether to build with optimizations.
- is_optimized = !is_debug
# Whether to enable assertions.
llvm_enable_assertions = true
# Whether to enable expensive checks.
llvm_enable_expensive_checks = false
+
+ # Whether to build with ThinLTO.
+ use_thinlto = false
+
+ # Max jobs per ThinLTO link.
+ max_jobs_per_lto_link = 8
+}
+
+# args that depend on other args must live in a later declare_args() block.
+declare_args() {
+ # Whether to build with optimizations.
+ is_optimized = !is_debug
}
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