Sami Tolvanen dc5723b02e kbuild: add support for Clang LTO ... This change adds build system support for Clang's Link Time Optimization (LTO). With -flto, instead of ELF object files, Clang produces LLVM bitcode, which is compiled into native code at link time, allowing the final binary to be optimized globally. For more details, see: https://llvm.org/docs/LinkTimeOptimization.html The Kconfig option CONFIG_LTO_CLANG is implemented as a choice, which defaults to LTO being disabled. To use LTO, the architecture must select ARCH_SUPPORTS_LTO_CLANG and support: - compiling with Clang, - compiling all assembly code with Clang's integrated assembler, - and linking with LLD. While using CONFIG_LTO_CLANG_FULL results in the best runtime performance, the compilation is not scalable in time or memory. CONFIG_LTO_CLANG_THIN enables ThinLTO, which allows parallel optimization and faster incremental builds. ThinLTO is used by default if the architecture also selects ARCH_SUPPORTS_LTO_CLANG_THIN: https://clang.llvm.org/docs/ThinLTO.html To enable LTO, LLVM tools must be used to handle bitcode files, by passing LLVM=1 and LLVM_IAS=1 options to make: $ make LLVM=1 LLVM_IAS=1 defconfig $ scripts/config -e LTO_CLANG_THIN $ make LLVM=1 LLVM_IAS=1 To prepare for LTO support with other compilers, common parts are gated behind the CONFIG_LTO option, and LTO can be disabled for specific files by filtering out CC_FLAGS_LTO. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20201211184633.3213045-3-samitolvanen@google.com		2021-01-14 08:21:08 -08:00
..
atomic	locking/atomics: Regenerate the atomics-check SHA1's	2020-11-07 13:20:41 +01:00
basic	kbuild: introduce hostprogs-always-y and userprogs-always-y	2020-08-10 01:32:59 +09:00
clang-tools	Makefile: Add clang-tidy and static analyzer support to makefile	2020-08-27 00:44:33 +09:00
coccinelle	coccinnelle: Remove ptr_ret script	2020-12-15 20:55:19 +01:00
dtc	scripts/dtc: Update to upstream version v1.6.0-31-gcbca977ea121	2020-10-12 09:58:15 -05:00
dummy-tools	kbuild: add dummy toolchains to enable all cc-option etc. in Kconfig	2020-04-09 00:13:45 +09:00
gcc-plugins	gcc-plugins: simplify GCC plugin-dev capability test	2020-12-04 14:09:55 -08:00
gdb	scripts/gdb/tasks: add headers and improve spacing format	2020-10-16 11:11:22 -07:00
genksyms	genksyms: Ignore module scoped _Static_assert()	2020-12-21 13:57:08 +09:00
kconfig	kconfig: fix return value of do_error_if()	2020-12-21 14:48:54 +09:00
ksymoops	…
mod	Kbuild updates for v5.11	2020-12-22 14:02:39 -08:00
package	builddeb: Fix rootless build in setuid/setgid directory	2020-11-02 11:31:00 +09:00
selinux	scripts/selinux,selinux: update mdp to enable policy capabilities	2020-08-17 20:42:00 -04:00
tracing	tweewide: Fix most Shebang lines	2020-12-08 23:30:04 +09:00
.gitignore	kbuild: preprocess module linker script	2020-09-25 00:36:41 +09:00
Kbuild.include	kbuild: remove leftover comment for filechk utility	2020-10-21 00:28:53 +09:00
Kconfig.include	kconfig: unify cc-option and as-option	2020-06-17 10:38:42 +09:00
Lindent	…
Makefile	kbuild: preprocess module linker script	2020-09-25 00:36:41 +09:00
Makefile.asm-generic	…
Makefile.build	kbuild: add support for Clang LTO	2021-01-14 08:21:08 -08:00
Makefile.clean	kbuild: introduce hostprogs-always-y and userprogs-always-y	2020-08-10 01:32:59 +09:00
Makefile.dtbinst	kbuild: refactor Makefile.dtbinst more	2020-03-25 10:19:43 +09:00
Makefile.extrawarn	Makefile.extrawarn: remove -Wnested-externs warning	2020-12-08 23:30:05 +09:00
Makefile.gcc-plugins	gcc-plugins/stackleak: Use asm instrumentation to avoid useless register saving	2020-06-24 07:48:28 -07:00
Makefile.headersinst	kbuild: move headers_check rule to usr/include/Makefile	2019-11-15 00:23:10 +09:00
Makefile.host	kbuild: sort hostprogs before passing it to ifneq	2020-08-10 01:32:59 +09:00
Makefile.kasan	kbuild: move CFLAGS_{KASAN,UBSAN,KCSAN} exports to relevant Makefiles	2020-09-25 00:36:50 +09:00
Makefile.kcov	kbuild: include scripts/Makefile.* only when relevant CONFIG is enabled	2020-08-10 01:32:59 +09:00
Makefile.kcsan	Kbuild updates for v5.10	2020-10-22 13:13:57 -07:00
Makefile.lib	kasan, arm64: expand CONFIG_KASAN checks	2020-12-22 12:55:08 -08:00
Makefile.modfinal	kbuild: add support for Clang LTO	2021-01-14 08:21:08 -08:00
Makefile.modinst	…
Makefile.modpost	kbuild: add support for Clang LTO	2021-01-14 08:21:08 -08:00
Makefile.modsign	…
Makefile.package	kbuild: fix broken builds because of GZIP,BZIP2,LZOP variables	2020-06-11 20:14:41 +09:00
Makefile.ubsan	ubsan: move cc-option tests into Kconfig	2020-12-15 22:46:18 -08:00
Makefile.userprogs	kbuild: add infrastructure to build userspace programs	2020-05-17 18:52:01 +09:00
adjust_autoksyms.sh	kbuild: split adjust_autoksyms.sh in two parts	2020-03-03 20:49:21 +09:00
asn1_compiler.c	…
bin2c.c	…
bloat-o-meter	tweewide: Fix most Shebang lines	2020-12-08 23:30:04 +09:00
bootgraph.pl	…
bpf_helpers_doc.py	bpf: Add a bpf_sock_from_file helper	2020-12-04 22:32:40 +01:00
cc-can-link.sh	…
check-sysctl-docs	docs: add a script to check sysctl docs	2020-02-25 03:35:16 -07:00
check_extable.sh	…
checkincludes.pl	…
checkkconfigsymbols.py	kconfig: remove '---help---' support	2020-08-14 13:30:03 +09:00
checkpatch.pl	checkpatch: prefer strscpy to strlcpy	2020-12-29 15:36:49 -08:00
checkstack.pl	scripts/checkstack.pl: fix arm sp regex	2020-05-26 00:03:16 +09:00
checksyscalls.sh	…
checkversion.pl	…
clang-version.sh	…
cleanfile	…
cleanpatch	…
coccicheck	scripts: coccicheck: Correct usage of make coccicheck	2020-12-24 12:59:43 +01:00
config	tweewide: Fix most Shebang lines	2020-12-08 23:30:04 +09:00
const_structs.checkpatch	const_structs.checkpatch: add pinctrl_ops and pinmux_ops	2020-10-16 11:11:21 -07:00
decode_stacktrace.sh	scripts/decode_stacktrace.sh: guess path to vmlinux by release name	2020-08-07 11:33:21 -07:00
decodecode	scripts/decodecode: add the capability to supply the program counter	2020-10-13 18:38:26 -07:00
depmod.sh	depmod: handle the case of /sbin/depmod without /sbin in PATH	2021-01-01 12:26:39 -08:00
dev-needs.sh	scripts/dev-needs: Add script to list device dependencies	2020-09-04 18:19:37 +02:00
diffconfig	tweewide: Fix most Shebang lines	2020-12-08 23:30:04 +09:00
documentation-file-ref-check	scripts: documentation-file-ref-check: Add line break before exit	2020-04-15 15:13:13 -06:00
export_report.pl	modpost: move the namespace field in Module.symvers last	2020-03-17 08:59:03 +09:00
extract-cert.c	extract-cert: add static to local data	2020-08-18 20:16:46 +09:00
extract-ikconfig	…
extract-module-sig.pl	…
extract-sys-certs.pl	…
extract-vmlinux	…
extract_xc3028.pl	…
faddr2line	…
file-size.sh	…
find-unused-docs.sh	scripts/find-unused-docs: Fix massive false positives	2020-01-27 14:25:06 -07:00
gcc-goto.sh	…
gcc-ld	…
gcc-version.sh	…
gcc-x86_32-has-stack-protector.sh	…
gcc-x86_64-has-stack-protector.sh	…
gen_autoksyms.sh	kbuild: generate autoksyms.h early	2020-03-03 20:49:21 +09:00
gen_ksymdeps.sh	…
get_abi.pl	tweewide: Fix most Shebang lines	2020-12-08 23:30:04 +09:00
get_dvb_firmware	…
get_feat.pl	scripts: get_feat.pl: reduce table width for all features output	2020-12-04 14:34:27 -07:00
get_maintainer.pl	get_maintainer: exclude MAINTAINERS file(s) from --git-fallback	2020-10-16 11:11:19 -07:00
gfp-translate	…
headerdep.pl	…
headers_check.pl	…
headers_install.sh	Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2020-08-07 13:29:39 -07:00
insert-sys-cert.c	…
jobserver-exec	docs, parallelism: Rearrange how jobserver reservations are made	2019-11-22 10:35:18 -07:00
kallsyms.c	scripts/kallsyms: skip ppc compiler stub *.long_branch.* / *.plt_branch.*	2020-09-25 00:41:54 +09:00
kernel-doc	scripts: kernel-doc: fix parsing function-like typedefs	2020-12-03 15:56:14 -07:00
ld-version.sh	…
leaking_addresses.pl	…
link-vmlinux.sh	kbuild: add support for Clang LTO	2021-01-14 08:21:08 -08:00
lld-version.sh	kbuild: Disable CONFIG_LD_ORPHAN_WARN for ld.lld 10.0.1	2020-12-01 22:46:06 +09:00
makelst	…
markup_oops.pl	…
mkcompile_h	kbuild: Use uname for LINUX_COMPILE_HOST detection	2020-10-21 00:46:04 +09:00
mkmakefile	kbuild: get rid of $(realpath ...) from scripts/mkmakefile	2019-08-29 23:54:29 +09:00
mksysmap	mksysmap: Fix the mismatch of '.L' symbols in System.map	2020-06-06 23:39:20 +09:00
mkuboot.sh	…
module.lds.S	kbuild: preprocess module linker script	2020-09-25 00:36:41 +09:00
modules-check.sh	kbuild: make module name conflict fatal error	2020-05-26 00:03:16 +09:00
nsdeps	kbuild: do not use scripts/ld-version.sh for checking spatch version	2020-12-12 18:31:29 +01:00
objdiff	…
parse-maintainers.pl	parse-maintainers: Do not sort section content by default	2020-03-26 15:08:27 -07:00
patch-kernel	…
profile2linkerlist.pl	…
prune-kernel	…
recordmcount.c	recordmcount: Fix build failure on non arm64	2020-08-10 15:22:06 +01:00
recordmcount.h	recordmcount: support >64k sections	2020-06-16 21:21:00 -04:00
recordmcount.pl	s390/ftrace: assume -mhotpatch or -mrecord-mcount always available	2020-11-20 19:19:11 +01:00
setlocalversion	scripts/setlocalversion: make git describe output more reliable	2020-09-25 02:28:12 +09:00
show_delta	tweewide: Fix most Shebang lines	2020-12-08 23:30:04 +09:00
sign-file.c	…
sorttable.c	s390/kernel: expand exception table logic to allow new handling options	2020-07-20 10:55:50 +02:00
sorttable.h	scripts/sorttable: Implement build-time ORC unwind table sorting	2019-12-13 10:47:58 +01:00
spdxcheck-test.sh	…
spdxcheck.py	scripts/spdxcheck.py: handle license identifiers in XML comments	2020-10-02 11:31:26 +02:00
spelling.txt	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2020-10-15 15:11:56 -07:00
sphinx-pre-install	tweewide: Fix most Shebang lines	2020-12-08 23:30:04 +09:00
split-man.pl	tweewide: Fix most Shebang lines	2020-12-08 23:30:04 +09:00
stackdelta	…
stackusage	…
subarch.include	…
tags.sh	Merge branch 'locking/urgent' into locking/core, to pick up fixes	2020-10-09 08:55:17 +02:00
tools-support-relr.sh	scripts/tools-support-relr.sh: un-quote variables	2019-11-13 10:52:05 +00:00
unifdef.c	…
ver_linux	ver_linux: Query ld cache for versions of libc/libcpp run-time	2020-02-10 13:35:15 -08:00
xen-hypercalls.sh	…
xz_wrap.sh	kbuild: add variables for compression tools	2020-06-06 23:42:01 +09:00