* [PATCH 1/2] kbuild: test --build-id linker flag by ld-option instead of cc-ldoption
@ 2018-02-23 4:56 Masahiro Yamada
2018-02-23 4:56 ` [PATCH 2/2] kbuild: simplify ld-option implementation Masahiro Yamada
0 siblings, 1 reply; 3+ messages in thread
From: Masahiro Yamada @ 2018-02-23 4:56 UTC (permalink / raw)
To: linux-kbuild
Cc: Arnd Bergmann, Sam Ravnborg, Nick Desaulniers, Matthias Kaehlcke,
Masahiro Yamada, Michal Marek, linux-kernel
'--build-id' is passed to $(LD), so it should be tested by 'ld-option'.
This seems a kind of misconversion when ld-option was renamed to
cc-ldoption.
Commit f86fd3066052 ("kbuild: rename ld-option to cc-ldoption") renamed
all instances of 'ld-option' to 'cc-ldoption'.
Then, commit 691ef3e7fdc1 ("kbuild: introduce ld-option") re-added
'ld-option' as a new implementation.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
---
Makefile | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/Makefile b/Makefile
index 4f295a2..1ed2a15 100644
--- a/Makefile
+++ b/Makefile
@@ -866,8 +866,7 @@ KBUILD_AFLAGS += $(ARCH_AFLAGS) $(KAFLAGS)
KBUILD_CFLAGS += $(ARCH_CFLAGS) $(KCFLAGS)
# Use --build-id when available.
-LDFLAGS_BUILD_ID := $(patsubst -Wl$(comma)%,%,\
- $(call cc-ldoption, -Wl$(comma)--build-id,))
+LDFLAGS_BUILD_ID := $(call ld-option, --build-id)
KBUILD_LDFLAGS_MODULE += $(LDFLAGS_BUILD_ID)
LDFLAGS_vmlinux += $(LDFLAGS_BUILD_ID)
--
2.7.4
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [PATCH 2/2] kbuild: simplify ld-option implementation
2018-02-23 4:56 [PATCH 1/2] kbuild: test --build-id linker flag by ld-option instead of cc-ldoption Masahiro Yamada
@ 2018-02-23 4:56 ` Masahiro Yamada
2018-02-26 23:22 ` Nick Desaulniers
0 siblings, 1 reply; 3+ messages in thread
From: Masahiro Yamada @ 2018-02-23 4:56 UTC (permalink / raw)
To: linux-kbuild
Cc: Arnd Bergmann, Sam Ravnborg, Nick Desaulniers, Matthias Kaehlcke,
Masahiro Yamada, Cao jin, Mark Charlebois, Michael Forney,
linux-kernel, Douglas Anderson, Josh Poimboeuf, Ingo Molnar
Currently, linker options are tested by the coordination of $(CC) and
$(LD) because LD needs some object to link.
As commit 86a9df597cdd ("kbuild: fix linker feature test macros when
cross compiling with Clang") addressed, we need to make sure $(CC)
and $(LD) agree the underlying architecture of the passed object.
This could be a bit complex when we combine tools from different groups.
For example, we can use clang for $(CC), but we still need to rely on
GCC toolchain for $(LD).
So, I was searching a way for standalone testing of linker options.
A trick I found is to use '-v'. This prints the version string, but
also tests if the given option is recognized.
If a given option is supported,
$ aarch64-linux-gnu-ld -v --fix-cortex-a53-843419
GNU ld (Linaro_Binutils-2017.11) 2.28.2.20170706
$ echo $?
0
If unsupported,
$ aarch64-linux-gnu-ld -v --fix-cortex-a53-843419
GNU ld (crosstool-NG linaro-1.13.1-4.7-2013.04-20130415 - Linaro GCC 2013.04) 2.23.1
aarch64-linux-gnu-ld: unrecognized option '--fix-cortex-a53-843419'
aarch64-linux-gnu-ld: use the --help option for usage information
$ echo $?
1
Gold works likewise.
$ aarch64-linux-gnu-ld.gold -v --fix-cortex-a53-843419
GNU gold (Linaro_Binutils-2017.11 2.28.2.20170706) 1.14
masahiro@pug:~/ref/linux$ echo $?
0
$ aarch64-linux-gnu-ld.gold -v --fix-cortex-a53-999999
GNU gold (Linaro_Binutils-2017.11 2.28.2.20170706) 1.14
aarch64-linux-gnu-ld.gold: --fix-cortex-a53-999999: unknown option
aarch64-linux-gnu-ld.gold: use the --help option for usage information
$ echo $?
1
LLD too.
$ ld.lld -v --gc-sections
LLD 7.0.0 (http://llvm.org/git/lld.git 4a0e4190e74cea19f8a8dc625ccaebdf8b5d1585) (compatible with GNU linkers)
$ echo $?
0
$ ld.lld -v --fix-cortex-a53-843419
LLD 7.0.0 (http://llvm.org/git/lld.git 4a0e4190e74cea19f8a8dc625ccaebdf8b5d1585) (compatible with GNU linkers)
$ echo $?
0
$ ld.lld -v --fix-cortex-a53-999999
ld.lld: error: unknown argument: --fix-cortex-a53-999999
LLD 7.0.0 (http://llvm.org/git/lld.git 4a0e4190e74cea19f8a8dc625ccaebdf8b5d1585) (compatible with GNU linkers)
$ echo $?
1
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
---
scripts/Kbuild.include | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
index 34cbd81..f9c2f07 100644
--- a/scripts/Kbuild.include
+++ b/scripts/Kbuild.include
@@ -237,9 +237,7 @@ cc-ldoption = $(call try-run-cached,\
# ld-option
# Usage: LDFLAGS += $(call ld-option, -X)
-ld-option = $(call try-run-cached,\
- $(CC) $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) -x c /dev/null -c -o "$$TMPO"; \
- $(LD) $(LDFLAGS) $(1) "$$TMPO" -o "$$TMP",$(1),$(2))
+ld-option = $(call try-run-cached, $(LD) $(LDFLAGS) $(1) -v,$(1),$(2))
# ar-option
# Usage: KBUILD_ARFLAGS := $(call ar-option,D)
--
2.7.4
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH 2/2] kbuild: simplify ld-option implementation
2018-02-23 4:56 ` [PATCH 2/2] kbuild: simplify ld-option implementation Masahiro Yamada
@ 2018-02-26 23:22 ` Nick Desaulniers
0 siblings, 0 replies; 3+ messages in thread
From: Nick Desaulniers @ 2018-02-26 23:22 UTC (permalink / raw)
To: Masahiro Yamada
Cc: Linux Kbuild mailing list, Arnd Bergmann, sam, Matthias Kaehlcke,
Cao jin, Mark Charlebois, forney, LKML, Doug Anderson,
Josh Poimboeuf, Ingo Molnar
Nice! Now we don't need to invoke $CC to find out info about linker support.
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
On Thu, Feb 22, 2018 at 8:57 PM Masahiro Yamada <
yamada.masahiro@socionext.com> wrote:
> Currently, linker options are tested by the coordination of $(CC) and
> $(LD) because LD needs some object to link.
> As commit 86a9df597cdd ("kbuild: fix linker feature test macros when
> cross compiling with Clang") addressed, we need to make sure $(CC)
> and $(LD) agree the underlying architecture of the passed object.
> This could be a bit complex when we combine tools from different groups.
> For example, we can use clang for $(CC), but we still need to rely on
> GCC toolchain for $(LD).
> So, I was searching a way for standalone testing of linker options.
> A trick I found is to use '-v'. This prints the version string, but
> also tests if the given option is recognized.
> If a given option is supported,
> $ aarch64-linux-gnu-ld -v --fix-cortex-a53-843419
> GNU ld (Linaro_Binutils-2017.11) 2.28.2.20170706
> $ echo $?
> 0
> If unsupported,
> $ aarch64-linux-gnu-ld -v --fix-cortex-a53-843419
> GNU ld (crosstool-NG linaro-1.13.1-4.7-2013.04-20130415 - Linaro GCC
> 2013.04) 2.23.1
> aarch64-linux-gnu-ld: unrecognized option '--fix-cortex-a53-843419'
> aarch64-linux-gnu-ld: use the --help option for usage information
> $ echo $?
> 1
> Gold works likewise.
> $ aarch64-linux-gnu-ld.gold -v --fix-cortex-a53-843419
> GNU gold (Linaro_Binutils-2017.11 2.28.2.20170706) 1.14
> masahiro@pug:~/ref/linux$ echo $?
> 0
> $ aarch64-linux-gnu-ld.gold -v --fix-cortex-a53-999999
> GNU gold (Linaro_Binutils-2017.11 2.28.2.20170706) 1.14
> aarch64-linux-gnu-ld.gold: --fix-cortex-a53-999999: unknown option
> aarch64-linux-gnu-ld.gold: use the --help option for usage information
> $ echo $?
> 1
> LLD too.
> $ ld.lld -v --gc-sections
> LLD 7.0.0 (http://llvm.org/git/lld.git
> 4a0e4190e74cea19f8a8dc625ccaebdf8b5d1585) (compatible with GNU linkers)
> $ echo $?
> 0
> $ ld.lld -v --fix-cortex-a53-843419
> LLD 7.0.0 (http://llvm.org/git/lld.git
> 4a0e4190e74cea19f8a8dc625ccaebdf8b5d1585) (compatible with GNU linkers)
> $ echo $?
> 0
> $ ld.lld -v --fix-cortex-a53-999999
> ld.lld: error: unknown argument: --fix-cortex-a53-999999
> LLD 7.0.0 (http://llvm.org/git/lld.git
> 4a0e4190e74cea19f8a8dc625ccaebdf8b5d1585) (compatible with GNU linkers)
> $ echo $?
> 1
> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
> ---
> scripts/Kbuild.include | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
> diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
> index 34cbd81..f9c2f07 100644
> --- a/scripts/Kbuild.include
> +++ b/scripts/Kbuild.include
> @@ -237,9 +237,7 @@ cc-ldoption = $(call try-run-cached,\
> # ld-option
> # Usage: LDFLAGS += $(call ld-option, -X)
> -ld-option = $(call try-run-cached,\
> - $(CC) $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) -x c /dev/null -c -o
> "$$TMPO"; \
> - $(LD) $(LDFLAGS) $(1) "$$TMPO" -o "$$TMP",$(1),$(2))
> +ld-option = $(call try-run-cached, $(LD) $(LDFLAGS) $(1) -v,$(1),$(2))
> # ar-option
> # Usage: KBUILD_ARFLAGS := $(call ar-option,D)
> --
> 2.7.4
--
Thanks,
~Nick Desaulniers
^ permalink raw reply [flat|nested] 3+ messages in thread
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