Commit Graph

3 Commits

Author SHA1 Message Date
evgeny 1ae8e8d25f Don't add -fsplit-lto-unit for thin LTO builds with PS4 and Darwin toolchains
These toolchains use legacy thin LTO API, which is not capable of unit splitting
Differential revision: https://reviews.llvm.org/D69173
2019-10-24 14:10:03 +03:00
Teresa Johnson dca5b94e79 [ThinLTO] Enable index-only WPD from clang
Summary:
To trigger the index-only Whole Program Devirt support added to LLVM, we
need to be able to specify -fno-split-lto-unit in conjunction with
-fwhole-program-vtables. Keep the default for -fwhole-program-vtables as
-fsplit-lto-unit, but don't error on that option combination.

Reviewers: pcc

Subscribers: mehdi_amini, inglorion, steven_wu, dexonsmith, arphaman, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D68029

llvm-svn: 373370
2019-10-01 18:08:29 +00:00
Teresa Johnson 84cecfcb3d [LTO] Add option to enable LTOUnit splitting, and disable unless needed
Summary:
Adds a new -f[no]split-lto-unit flag that is disabled by default to
control module splitting during ThinLTO. It is automatically enabled
for -fsanitize=cfi and -fwhole-program-vtables.

The new EnableSplitLTOUnit codegen flag is passed down to llvm
via a new module flag of the same name.

Depends on D53890.

Reviewers: pcc

Subscribers: ormris, mehdi_amini, inglorion, eraman, steven_wu, dexonsmith, cfe-commits, llvm-commits

Differential Revision: https://reviews.llvm.org/D53891

llvm-svn: 350949
2019-01-11 18:32:07 +00:00