VisionFive2 Linux kernel

author: Sami Tolvanen <samitolvanen@google.com> 2020-12-11 10:46:19 -0800 committer: Kees Cook <keescook@chromium.org> 2021-01-14 08:21:08 -0800 commit: dc5723b02e523b2c4a68667f7e28c65018f7202f parent: 3b15cdc15956673ba1551d79bceae471436ac6a9

Commit Summary:

kbuild: add support for Clang LTO

Diffstat:

1 file changed, 16 insertions, 2 deletions

diff --git a/Makefile b/Makefile
index b434c342080b..2b9bcecd6ea1 100644
--- a/Makefile
+++ b/Makefile
@@ -893,6 +893,21 @@ KBUILD_CFLAGS	+= $(CC_FLAGS_SCS)
 export CC_FLAGS_SCS
 endif
 
+ifdef CONFIG_LTO_CLANG
+ifdef CONFIG_LTO_CLANG_THIN
+CC_FLAGS_LTO	+= -flto=thin -fsplit-lto-unit
+KBUILD_LDFLAGS	+= --thinlto-cache-dir=$(extmod-prefix).thinlto-cache
+else
+CC_FLAGS_LTO	+= -flto
+endif
+CC_FLAGS_LTO	+= -fvisibility=hidden
+endif
+
+ifdef CONFIG_LTO
+KBUILD_CFLAGS	+= $(CC_FLAGS_LTO)
+export CC_FLAGS_LTO
+endif
+
 ifdef CONFIG_DEBUG_FORCE_FUNCTION_ALIGN_32B
 KBUILD_CFLAGS += -falign-functions=32
 endif
@@ -1479,7 +1494,7 @@ MRPROPER_FILES += include/config include/generated          \
 		  *.spec
 
 # Directories & files removed with 'make distclean'
-DISTCLEAN_FILES += tags TAGS cscope* GPATH GTAGS GRTAGS GSYMS
+DISTCLEAN_FILES += tags TAGS cscope* GPATH GTAGS GRTAGS GSYMS .thinlto-cache
 
 # clean - Delete most, but leave enough to build external modules
 #
@@ -1725,7 +1740,7 @@ PHONY += compile_commands.json
 
 clean-dirs := $(KBUILD_EXTMOD)
 clean: rm-files := $(KBUILD_EXTMOD)/Module.symvers $(KBUILD_EXTMOD)/modules.nsdeps \
-	$(KBUILD_EXTMOD)/compile_commands.json
+	$(KBUILD_EXTMOD)/compile_commands.json $(KBUILD_EXTMOD)/.thinlto-cache
 
 PHONY += help
 help: