* [PATCH v4 1/2] kbuild: move vmlinux.a build rule to scripts/Makefile.vmlinux_a
2025-10-27 22:09 [PATCH v4 0/2] kbuild: distributed build support for Clang ThinLTO xur
@ 2025-10-27 22:09 ` xur
2025-10-27 22:09 ` [PATCH v4 2/2] kbuild: distributed build support for Clang ThinLTO xur
2025-10-28 10:43 ` [PATCH v4 0/2] " Piotr Gorski
2 siblings, 0 replies; 5+ messages in thread
From: xur @ 2025-10-27 22:09 UTC (permalink / raw)
To: Masahiro Yamada, Nathan Chancellor, Nicolas Schier,
Nick Desaulniers, Bill Wendling, Justin Stitt, Miguel Ojeda,
Thomas Gleixner, Alice Ryhl, Sami Tolvanen,
Mike Rapoport (Microsoft), Rafael Aquini, Michael Ellerman,
Stafford Horne, Christophe Leroy, Piotr Gorski, Rong Xu,
Teresa Johnson
Cc: linux-kernel, linux-kbuild, llvm
From: Rong Xu <xur@google.com>
From: Masahiro Yamada <masahiroy@kernel.org>
Move the build rule for vmlinux.a to a separate file in preparation
for supporting distributed builds with Clang ThinLTO.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Rong Xu <xur@google.com>
---
Makefile | 16 +++++--------
scripts/Makefile.vmlinux_a | 46 ++++++++++++++++++++++++++++++++++++++
2 files changed, 52 insertions(+), 10 deletions(-)
create mode 100644 scripts/Makefile.vmlinux_a
diff --git a/Makefile b/Makefile
index b34a1f4c03967..89a25bac2bbab 100644
--- a/Makefile
+++ b/Makefile
@@ -1198,7 +1198,7 @@ export ARCH_DRIVERS := $(drivers-y) $(drivers-m)
KBUILD_VMLINUX_OBJS := built-in.a $(patsubst %/, %/lib.a, $(filter %/, $(libs-y)))
KBUILD_VMLINUX_LIBS := $(filter-out %/, $(libs-y))
-export KBUILD_VMLINUX_LIBS
+export KBUILD_VMLINUX_OBJS KBUILD_VMLINUX_LIBS
export KBUILD_LDS := arch/$(SRCARCH)/kernel/vmlinux.lds
ifdef CONFIG_TRIM_UNUSED_KSYMS
@@ -1207,16 +1207,12 @@ ifdef CONFIG_TRIM_UNUSED_KSYMS
KBUILD_MODULES := y
endif
-# '$(AR) mPi' needs 'T' to workaround the bug of llvm-ar <= 14
-quiet_cmd_ar_vmlinux.a = AR $@
- cmd_ar_vmlinux.a = \
- rm -f $@; \
- $(AR) cDPrST $@ $(KBUILD_VMLINUX_OBJS); \
- $(AR) mPiT $$($(AR) t $@ | sed -n 1p) $@ $$($(AR) t $@ | grep -F -f $(srctree)/scripts/head-object-list.txt)
+PHONY += vmlinux_a
+vmlinux_a: $(KBUILD_VMLINUX_OBJS) scripts/head-object-list.txt FORCE
+ $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.vmlinux_a
-targets += vmlinux.a
-vmlinux.a: $(KBUILD_VMLINUX_OBJS) scripts/head-object-list.txt FORCE
- $(call if_changed,ar_vmlinux.a)
+vmlinux.a: vmlinux_a
+ @:
PHONY += vmlinux_o
vmlinux_o: vmlinux.a $(KBUILD_VMLINUX_LIBS)
diff --git a/scripts/Makefile.vmlinux_a b/scripts/Makefile.vmlinux_a
new file mode 100644
index 0000000000000..9774f02b43b2f
--- /dev/null
+++ b/scripts/Makefile.vmlinux_a
@@ -0,0 +1,46 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+PHONY := __default
+__default: vmlinux.a
+
+include include/config/auto.conf
+include $(srctree)/scripts/Kbuild.include
+include $(srctree)/scripts/Makefile.lib
+
+# Link of built-in-fixup.a
+# ---------------------------------------------------------------------------
+
+# '$(AR) mPi' needs --thin to workaround the bug of llvm-ar <= 14
+quiet_cmd_ar_builtin_fixup = AR $@
+ cmd_ar_builtin_fixup = \
+ rm -f $@; \
+ $(AR) cDPrS --thin $@ $(KBUILD_VMLINUX_OBJS); \
+ $(AR) mPi --thin $$($(AR) t $@ | sed -n 1p) $@ $$($(AR) t $@ | grep -F -f $(srctree)/scripts/head-object-list.txt)
+
+targets += built-in-fixup.a
+built-in-fixup.a: $(KBUILD_VMLINUX_OBJS) scripts/head-object-list.txt FORCE
+ $(call if_changed,ar_builtin_fixup)
+
+# vmlinux.a
+# ---------------------------------------------------------------------------
+
+targets += vmlinux.a
+vmlinux.a: built-in-fixup.a FORCE
+ $(call if_changed,copy)
+
+# Add FORCE to the prerequisites of a target to force it to be always rebuilt.
+# ---------------------------------------------------------------------------
+
+PHONY += FORCE
+FORCE:
+
+# Read all saved command lines and dependencies for the $(targets) we
+# may be building above, using $(if_changed{,_dep}). As an
+# optimization, we don't need to read them if the target does not
+# exist, we will rebuild anyway in that case.
+
+existing-targets := $(wildcard $(sort $(targets)))
+
+-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
+
+.PHONY: $(PHONY)
--
2.51.1.838.g19442a804e-goog
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH v4 2/2] kbuild: distributed build support for Clang ThinLTO
2025-10-27 22:09 [PATCH v4 0/2] kbuild: distributed build support for Clang ThinLTO xur
2025-10-27 22:09 ` [PATCH v4 1/2] kbuild: move vmlinux.a build rule to scripts/Makefile.vmlinux_a xur
@ 2025-10-27 22:09 ` xur
2025-10-28 10:43 ` [PATCH v4 0/2] " Piotr Gorski
2 siblings, 0 replies; 5+ messages in thread
From: xur @ 2025-10-27 22:09 UTC (permalink / raw)
To: Masahiro Yamada, Nathan Chancellor, Nicolas Schier,
Nick Desaulniers, Bill Wendling, Justin Stitt, Miguel Ojeda,
Thomas Gleixner, Alice Ryhl, Sami Tolvanen,
Mike Rapoport (Microsoft), Rafael Aquini, Michael Ellerman,
Stafford Horne, Christophe Leroy, Piotr Gorski, Rong Xu,
Teresa Johnson
Cc: linux-kernel, linux-kbuild, llvm
From: Rong Xu <xur@google.com>
Add distributed ThinLTO build support for the Linux kernel.
This new mode offers several advantages: (1) Increased
flexibility in handling user-specified build options.
(2) Improved user-friendliness for developers. (3) Greater
convenience for integrating with objtool and livepatch.
Note that "distributed" in this context refers to a term
that differentiates in-process ThinLTO builds by invoking
backend compilation through the linker, not necessarily
building in distributed environments.
Distributed ThinLTO is enabled via the
`CONFIG_LTO_CLANG_THIN_DIST` Kconfig option. For example:
> make LLVM=1 defconfig
> scripts/config -e LTO_CLANG_THIN_DIST
> make LLVM=1 oldconfig
> make LLVM=1 vmlinux -j <..>
The build flow proceeds in four stages:
1. Perform FE compilation, mirroring the in-process ThinLTO mode.
2. Thin-link the generated IR files and object files.
3. Find all IR files and perform BE compilation, using the flags
stored in the .*.o.cmd files.
4. Link the BE results to generate the final vmlinux.o.
NOTE: This patch currently implements the build for the main kernel
image (vmlinux) only. Kernel module support is planned for a
subsequent patch.
Tested on the following arch: x86, arm64, loongarch, and
riscv.
The earlier implementation details can be found here:
https://discourse.llvm.org/t/rfc-distributed-thinlto-build-for-kernel/85934
Signed-off-by: Rong Xu <xur@google.com>
Co-developed-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---
.gitignore | 2 ++
Makefile | 9 +++++----
arch/Kconfig | 19 ++++++++++++++++++
scripts/Makefile.lib | 7 +++++++
scripts/Makefile.thinlto | 40 ++++++++++++++++++++++++++++++++++++++
scripts/Makefile.vmlinux_a | 37 +++++++++++++++++++++++++++++++++++
scripts/mod/modpost.c | 15 +++++++++++---
7 files changed, 122 insertions(+), 7 deletions(-)
create mode 100644 scripts/Makefile.thinlto
diff --git a/.gitignore b/.gitignore
index 86a1ba0d90353..d34f28ca55400 100644
--- a/.gitignore
+++ b/.gitignore
@@ -55,6 +55,7 @@
*.zst
Module.symvers
dtbs-list
+builtin.order
modules.order
#
@@ -66,6 +67,7 @@ modules.order
/vmlinux.32
/vmlinux.map
/vmlinux.symvers
+/vmlinux.thinlto-index
/vmlinux.unstripped
/vmlinux-gdb.py
/vmlinuz
diff --git a/Makefile b/Makefile
index 89a25bac2bbab..a608a082599d9 100644
--- a/Makefile
+++ b/Makefile
@@ -1000,10 +1000,10 @@ export CC_FLAGS_SCS
endif
ifdef CONFIG_LTO_CLANG
-ifdef CONFIG_LTO_CLANG_THIN
-CC_FLAGS_LTO := -flto=thin -fsplit-lto-unit
-else
+ifdef CONFIG_LTO_CLANG_FULL
CC_FLAGS_LTO := -flto
+else
+CC_FLAGS_LTO := -flto=thin -fsplit-lto-unit
endif
CC_FLAGS_LTO += -fvisibility=hidden
@@ -1572,6 +1572,7 @@ endif # CONFIG_MODULES
CLEAN_FILES += vmlinux.symvers modules-only.symvers \
modules.builtin modules.builtin.modinfo modules.nsdeps \
modules.builtin.ranges vmlinux.o.map vmlinux.unstripped \
+ vmlinux.thinlto-index builtin.order \
compile_commands.json rust/test \
rust-project.json .vmlinux.objs .vmlinux.export.c \
.builtin-dtbs-list .builtin-dtb.S
@@ -2014,7 +2015,7 @@ clean: $(clean-dirs)
$(call cmd,rmfiles)
@find . $(RCS_FIND_IGNORE) \
\( -name '*.[aios]' -o -name '*.rsi' -o -name '*.ko' -o -name '.*.cmd' \
- -o -name '*.ko.*' \
+ -o -name '*.ko.*' -o -name '*.o.thinlto.bc' \
-o -name '*.dtb' -o -name '*.dtbo' \
-o -name '*.dtb.S' -o -name '*.dtbo.S' \
-o -name '*.dt.yaml' -o -name 'dtbs-list' \
diff --git a/arch/Kconfig b/arch/Kconfig
index 74ff011335322..f323ff2f12f87 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -864,6 +864,25 @@ config LTO_CLANG_THIN
https://clang.llvm.org/docs/ThinLTO.html
If unsure, say Y.
+
+config LTO_CLANG_THIN_DIST
+ bool "Clang ThinLTO in distributed mode (EXPERIMENTAL)"
+ depends on HAS_LTO_CLANG && ARCH_SUPPORTS_LTO_CLANG_THIN
+ select LTO_CLANG
+ help
+ This option enables Clang's ThinLTO in distributed build mode.
+ In this mode, the linker performs the thin-link, generating
+ ThinLTO index files. Subsequently, the build system explicitly
+ invokes ThinLTO backend compilation using these index files
+ and pre-linked IR objects. The resulting native object files
+ are with the .thinlto-native.o suffix.
+
+ This build mode offers improved visibility into the ThinLTO
+ process through explicit subcommand exposure. It also makes
+ final native object files directly available, benefiting
+ tools like objtool and kpatch. Additionally, it provides
+ crucial granular control over back-end options, enabling
+ module-specific compiler options, and simplifies debugging.
endchoice
config ARCH_SUPPORTS_AUTOFDO_CLANG
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 1d581ba5df66f..65470adaa89ca 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -239,6 +239,12 @@ ifdef CONFIG_LTO_CLANG
cmd_ld_single = $(if $(objtool-enabled)$(is-single-obj-m), ; $(LD) $(ld_flags) -r -o $(tmp-target) $@; mv $(tmp-target) $@)
endif
+ifdef CONFIG_LTO_CLANG_THIN_DIST
+# Save the _c_flags, sliently.
+quiet_cmd_save_c_flags =
+ cmd_save_c_flags = printf '\n%s\n' 'saved_c_flags_$@ := $(_c_flags)' >> $(dot-target).cmd
+endif
+
quiet_cmd_cc_o_c = CC $(quiet_modtag) $@
cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $< \
$(cmd_ld_single) \
@@ -246,6 +252,7 @@ quiet_cmd_cc_o_c = CC $(quiet_modtag) $@
define rule_cc_o_c
$(call cmd_and_fixdep,cc_o_c)
+ $(call cmd,save_c_flags)
$(call cmd,checksrc)
$(call cmd,checkdoc)
$(call cmd,gen_objtooldep)
diff --git a/scripts/Makefile.thinlto b/scripts/Makefile.thinlto
new file mode 100644
index 0000000000000..03349ac69de5f
--- /dev/null
+++ b/scripts/Makefile.thinlto
@@ -0,0 +1,40 @@
+PHONY := __default
+__default:
+
+include include/config/auto.conf
+include $(srctree)/scripts/Kbuild.include
+include $(srctree)/scripts/Makefile.lib
+
+native-objs := $(patsubst %.o,%.thinlto-native.o,$(call read-file, vmlinux.thinlto-index))
+
+__default: $(native-objs)
+
+# Generate .thinlto-native.o (obj) from .o (bitcode) and .thinlto.bc (summary) files
+# ---------------------------------------------------------------------------
+quiet_cmd_cc_o_bc = CC $(quiet_modtag) $@
+ be_flags = $(shell sed -n '/saved_c_flags_/s/.*:= //p' \
+ $(dir $(<)).$(notdir $(<)).cmd)
+ cmd_cc_o_bc = \
+ $(CC) $(be_flags) -x ir -fno-lto -Wno-unused-command-line-argument \
+ -fthinlto-index=$(word 2, $^) -c -o $@ $<
+
+targets += $(native-objs)
+$(native-objs): %.thinlto-native.o: %.o %.o.thinlto.bc FORCE
+ $(call if_changed,cc_o_bc)
+
+# Add FORCE to the prerequisites of a target to force it to be always rebuilt.
+# ---------------------------------------------------------------------------
+
+PHONY += FORCE
+FORCE:
+
+# Read all saved command lines and dependencies for the $(targets) we
+# may be building above, using $(if_changed{,_dep}). As an
+# optimization, we don't need to read them if the target does not
+# exist, we will rebuild anyway in that case.
+
+existing-targets := $(wildcard $(sort $(targets)))
+
+-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
+
+.PHONY: $(PHONY)
diff --git a/scripts/Makefile.vmlinux_a b/scripts/Makefile.vmlinux_a
index 9774f02b43b2f..382cebe1ee571 100644
--- a/scripts/Makefile.vmlinux_a
+++ b/scripts/Makefile.vmlinux_a
@@ -21,6 +21,41 @@ targets += built-in-fixup.a
built-in-fixup.a: $(KBUILD_VMLINUX_OBJS) scripts/head-object-list.txt FORCE
$(call if_changed,ar_builtin_fixup)
+ifdef CONFIG_LTO_CLANG_THIN_DIST
+
+quiet_cmd_builtin.order = GEN $@
+ cmd_builtin.order = $(AR) t $< > $@
+
+targets += builtin.order
+builtin.order: built-in-fixup.a FORCE
+ $(call if_changed,builtin.order)
+
+quiet_cmd_ld_thinlto_index = LD $@
+ cmd_ld_thinlto_index = \
+ $(LD) $(KBUILD_LDFLAGS) -r --thinlto-index-only=$@ @$<
+
+targets += vmlinux.thinlto-index
+vmlinux.thinlto-index: builtin.order FORCE
+ $(call if_changed,ld_thinlto_index)
+
+quiet_cmd_ar_vmlinux.a = GEN $@
+ cmd_ar_vmlinux.a = \
+ rm -f $@; \
+ while read -r obj; do \
+ if grep -q $${obj} $(word 2, $^); then \
+ echo $${obj%.o}.thinlto-native.o; \
+ else \
+ echo $${obj}; \
+ fi; \
+ done < $< | xargs $(AR) cDPrS --thin $@
+
+targets += vmlinux.a
+vmlinux.a: builtin.order vmlinux.thinlto-index FORCE
+ $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.thinlto
+ $(call if_changed,ar_vmlinux.a)
+
+else
+
# vmlinux.a
# ---------------------------------------------------------------------------
@@ -28,6 +63,8 @@ targets += vmlinux.a
vmlinux.a: built-in-fixup.a FORCE
$(call if_changed,copy)
+endif
+
# Add FORCE to the prerequisites of a target to force it to be always rebuilt.
# ---------------------------------------------------------------------------
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 47c8aa2a69392..38f62eb4bd8ba 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -1473,13 +1473,22 @@ static void extract_crcs_for_object(const char *object, struct module *mod)
char cmd_file[PATH_MAX];
char *buf, *p;
const char *base;
- int dirlen, ret;
+ int dirlen, baselen_without_suffix, ret;
base = get_basename(object);
dirlen = base - object;
- ret = snprintf(cmd_file, sizeof(cmd_file), "%.*s.%s.cmd",
- dirlen, object, base);
+ baselen_without_suffix = strlen(object) - dirlen - strlen(".o");
+
+ /*
+ * When CONFIG_LTO_CLANG_THIN_DIST=y, the ELF is *.thinlto-native.o
+ * but the symbol CRCs are recorded in *.o.cmd file.
+ */
+ if (strends(object, ".thinlto-native.o"))
+ baselen_without_suffix -= strlen(".thinlto-native");
+
+ ret = snprintf(cmd_file, sizeof(cmd_file), "%.*s.%.*s.o.cmd",
+ dirlen, object, baselen_without_suffix, base);
if (ret >= sizeof(cmd_file)) {
error("%s: too long path was truncated\n", cmd_file);
return;
--
2.51.1.838.g19442a804e-goog
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH v4 0/2] kbuild: distributed build support for Clang ThinLTO
2025-10-27 22:09 [PATCH v4 0/2] kbuild: distributed build support for Clang ThinLTO xur
2025-10-27 22:09 ` [PATCH v4 1/2] kbuild: move vmlinux.a build rule to scripts/Makefile.vmlinux_a xur
2025-10-27 22:09 ` [PATCH v4 2/2] kbuild: distributed build support for Clang ThinLTO xur
@ 2025-10-28 10:43 ` Piotr Gorski
2025-10-28 17:07 ` Rong Xu
2 siblings, 1 reply; 5+ messages in thread
From: Piotr Gorski @ 2025-10-28 10:43 UTC (permalink / raw)
To: xur, Masahiro Yamada, Nathan Chancellor, Nicolas Schier,
Nick Desaulniers, Bill Wendling, Justin Stitt, Miguel Ojeda,
Thomas Gleixner, Alice Ryhl, Sami Tolvanen,
Mike Rapoport (Microsoft), Rafael Aquini, Michael Ellerman,
Stafford Horne, Christophe Leroy, Teresa Johnson
Cc: linux-kernel, linux-kbuild, llvm
I tried using this on kernel 6.17.5, but unfortunately I get this error.
I previously tested the version in CachyOS:
https://github.com/CachyOS/linux/commit/68984063b5e27854272241549e47cb2930ef9710
and https://github.com/CachyOS/linux/
commit/00a3ff73a566b7e27b4ced46af4ce27177d9fc37 and everything works fine.
/bin/sh: -c: line 1: syntax error near unexpected token `('
/bin/sh: -c: line 1: `set -e; trap 'rm -f
drivers/net/wireguard/main.o; trap - HUP; kill -s HUP $$' HUP; trap 'rm
-f drivers/net/wireguard/main.o; trap - INT; kill -s INT $$' INT; trap
'rm -f drivers/net/wireguard/main.o
; trap - QUIT; kill -s QUIT $$' QUIT; trap 'rm -f
drivers/net/wireguard/main.o; trap - TERM; kill -s TERM $$' TERM; trap
'rm -f drivers/net/wireguard/main.o; trap - PIPE; kill -s PIPE $$' PIPE;
printf '\n%s\n' 'saved_c_flag
s_drivers/net/wireguard/main.o := -D__KERNEL__ --target=x86_64-linux-gnu
-fintegrated-as -Werror=ignored-optimization-argument
-Werror=option-ignored -std=gnu11 -fshort-wchar -funsigned-char
-fno-common -fno-PIE -fno-strict-a
liasing -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx
-fcf-protection=branch -fno-jump-tables -m64 -falign-loops=1 -mno-80387
-mno-fp-ret-in-387 -mstack-alignment=8 -mskip-rax-setup -march=znver4
-mno-red-zone -mcmodel=kern
el -mstack-protector-guard-reg=gs
-mstack-protector-guard-symbol=__ref_stack_chk_guard -Wno-sign-compare
-fno-asynchronous-unwind-tables -mretpoline-external-thunk
-mindirect-branch-cs-prefix -mfunction-return=thunk-extern -m
harden-sls=all -fpatchable-function-entry=16,16
-fno-delete-null-pointer-checks -O3 -fstack-protector-strong
-ftrivial-auto-var-init=zero -fno-stack-clash-protection -pg -mfentry
-DCC_USING_NOP_MCOUNT -DCC_USING_FENTRY -fno-l
to -flto=thin -fsplit-lto-unit -fvisibility=hidden -falign-functions=16
-fstrict-flex-arrays=3 -fno-strict-overflow -fno-stack-check
-fno-builtin-wcslen -Wall -Wextra -Wundef
-Werror=implicit-function-declaration -Werror=impl
icit-int -Werror=return-type -Wno-format-security -Wno-trigraphs
-Wno-frame-address -Wno-address-of-packed-member -Wmissing-declarations
-Wmissing-prototypes -Wframe-larger-than=2048 -Wno-gnu
-Wno-format-overflow-non-kprintf
-Wno-format-truncation-non-kprintf -Wno-default-const-init-unsafe
-Wno-pointer-sign -Wcast-function-type
-Wno-unterminated-string-initialization -Wimplicit-fallthrough
-Werror=date-time -Wenum-conversion -Wunused -Wno-unused-
but-set-variable -Wno-unused-const-variable -Wno-format-overflow
-Wno-override-init -Wno-pointer-to-enum-cast
-Wno-tautological-constant-out-of-range-compare -Wno-unaligned-access
-Wno-enum-compare-conditional -Wno-missing-fi
eld-initializers -Wno-type-limits -Wno-shift-negative-value
-Wno-enum-enum-conversion -Wno-sign-compare -Wno-unused-parameter -g
-gdwarf-5 -D'pr_fmt(fmt)=KBUILD_MODNAME ": " fmt'' >>
drivers/net/wireguard/.main.o.cmd'
make[5]: *** [scripts/Makefile.build:287: drivers/net/wireguard/main.o]
Error 2
make[5]: *** Deleting file 'drivers/net/wireguard/main.o'
make[4]: *** [scripts/Makefile.build:556: drivers/net/wireguard] Error 2
LLVM/CLANG: 21.1.4
If necessary, I can send more logs.
Best regards,
Piotr
W dniu 27.10.2025 o 23:09, xur@google.com pisze:
> From: Rong Xu <xur@google.com>
>
> This V4 is based on the reimplementation provided by Masahiro Yamada
> on May 26. The difference is that this version now saves the compiler
> flags (_c_flags) from the Front-End (FE) compilation and re-uses them
> for the subsequent Back-End (BE) compilation.
>
> Rong Xu (2):
> kbuild: move vmlinux.a build rule to scripts/Makefile.vmlinux_a
> kbuild: distributed build support for Clang ThinLTO
>
> .gitignore | 2 +
> Makefile | 25 +++++-------
> arch/Kconfig | 19 +++++++++
> scripts/Makefile.lib | 7 ++++
> scripts/Makefile.thinlto | 40 ++++++++++++++++++
> scripts/Makefile.vmlinux_a | 83 ++++++++++++++++++++++++++++++++++++++
> scripts/mod/modpost.c | 15 +++++--
> 7 files changed, 174 insertions(+), 17 deletions(-)
> create mode 100644 scripts/Makefile.thinlto
> create mode 100644 scripts/Makefile.vmlinux_a
>
>
> base-commit: dcb6fa37fd7bc9c3d2b066329b0d27dedf8becaa
^ permalink raw reply [flat|nested] 5+ messages in thread