diff mbox series

[v2] Makefile: Fix GCC_TOOLCHAIN_DIR prefix for Clang cross compilation

Message ID 20200721041940.4029552-1-maskray@google.com (mailing list archive)
State New, archived
Headers show
Series [v2] Makefile: Fix GCC_TOOLCHAIN_DIR prefix for Clang cross compilation | expand

Commit Message

Fangrui Song July 21, 2020, 4:19 a.m. UTC 
When CROSS_COMPILE is set (e.g. aarch64-linux-gnu-), if
$(CROSS_COMPILE)elfedit is found at /usr/bin/aarch64-linux-gnu-elfedit,
GCC_TOOLCHAIN_DIR will be set to /usr/bin/.  --prefix= will be set to
/usr/bin/ and Clang as of 11 will search for both
$(prefix)aarch64-linux-gnu-$needle and $(prefix)$needle.

GCC searchs for $(prefix)aarch64-linux-gnu/$version/$needle,
$(prefix)aarch64-linux-gnu/$needle and $(prefix)$needle. In practice,
$(prefix)aarch64-linux-gnu/$needle rarely contains executables.

To better model how GCC's -B/--prefix takes in effect in practice, newer
Clang (since
https://github.com/llvm/llvm-project/commit/3452a0d8c17f7166f479706b293caf6ac76ffd90)
only searches for $(prefix)$needle. Currently it will find /usr/bin/as
instead of /usr/bin/aarch64-linux-gnu-as.

Set --prefix= to $(GCC_TOOLCHAIN_DIR)$(CROSS_COMPILE)
(/usr/bin/aarch64-linux-gnu-) so that newer Clang can find the
appropriate cross compiling GNU as (when -no-integrated-as is in
effect).

Reported-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Fangrui Song <maskray@google.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://github.com/ClangBuiltLinux/linux/issues/1099
---
Changes in v2:
* Updated description to add tags and the llvm-project commit link.
* Fixed a typo.
---
 Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Greg KH July 21, 2020, 10:40 a.m. UTC | #1 
On Mon, Jul 20, 2020 at 09:19:38PM -0700, Fangrui Song wrote:
> When CROSS_COMPILE is set (e.g. aarch64-linux-gnu-), if
> $(CROSS_COMPILE)elfedit is found at /usr/bin/aarch64-linux-gnu-elfedit,
> GCC_TOOLCHAIN_DIR will be set to /usr/bin/.  --prefix= will be set to
> /usr/bin/ and Clang as of 11 will search for both
> $(prefix)aarch64-linux-gnu-$needle and $(prefix)$needle.
> 
> GCC searchs for $(prefix)aarch64-linux-gnu/$version/$needle,
> $(prefix)aarch64-linux-gnu/$needle and $(prefix)$needle. In practice,
> $(prefix)aarch64-linux-gnu/$needle rarely contains executables.
> 
> To better model how GCC's -B/--prefix takes in effect in practice, newer
> Clang (since
> https://github.com/llvm/llvm-project/commit/3452a0d8c17f7166f479706b293caf6ac76ffd90)
> only searches for $(prefix)$needle. Currently it will find /usr/bin/as
> instead of /usr/bin/aarch64-linux-gnu-as.
> 
> Set --prefix= to $(GCC_TOOLCHAIN_DIR)$(CROSS_COMPILE)
> (/usr/bin/aarch64-linux-gnu-) so that newer Clang can find the
> appropriate cross compiling GNU as (when -no-integrated-as is in
> effect).
> 
> Reported-by: Nathan Chancellor <natechancellor@gmail.com>
> Signed-off-by: Fangrui Song <maskray@google.com>
> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
> Tested-by: Nathan Chancellor <natechancellor@gmail.com>
> Tested-by: Nick Desaulniers <ndesaulniers@google.com>
> Link: https://github.com/ClangBuiltLinux/linux/issues/1099
> ---
> Changes in v2:
> * Updated description to add tags and the llvm-project commit link.
> * Fixed a typo.


<formletter>

This is not the correct way to submit patches for inclusion in the
stable kernel tree.  Please read:
    https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.

</formletter>
Sedat Dilek July 21, 2020, 2:52 p.m. UTC | #2 
On Tue, Jul 21, 2020 at 12:40 PM Greg KH <gregkh@linuxfoundation.org> wrote:
>
> On Mon, Jul 20, 2020 at 09:19:38PM -0700, Fangrui Song wrote:
> > When CROSS_COMPILE is set (e.g. aarch64-linux-gnu-), if
> > $(CROSS_COMPILE)elfedit is found at /usr/bin/aarch64-linux-gnu-elfedit,
> > GCC_TOOLCHAIN_DIR will be set to /usr/bin/.  --prefix= will be set to
> > /usr/bin/ and Clang as of 11 will search for both
> > $(prefix)aarch64-linux-gnu-$needle and $(prefix)$needle.
> >
> > GCC searchs for $(prefix)aarch64-linux-gnu/$version/$needle,
> > $(prefix)aarch64-linux-gnu/$needle and $(prefix)$needle. In practice,
> > $(prefix)aarch64-linux-gnu/$needle rarely contains executables.
> >
> > To better model how GCC's -B/--prefix takes in effect in practice, newer
> > Clang (since
> > https://github.com/llvm/llvm-project/commit/3452a0d8c17f7166f479706b293caf6ac76ffd90)
> > only searches for $(prefix)$needle. Currently it will find /usr/bin/as
> > instead of /usr/bin/aarch64-linux-gnu-as.
> >
> > Set --prefix= to $(GCC_TOOLCHAIN_DIR)$(CROSS_COMPILE)
> > (/usr/bin/aarch64-linux-gnu-) so that newer Clang can find the
> > appropriate cross compiling GNU as (when -no-integrated-as is in
> > effect).
> >
> > Reported-by: Nathan Chancellor <natechancellor@gmail.com>
> > Signed-off-by: Fangrui Song <maskray@google.com>
> > Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
> > Tested-by: Nathan Chancellor <natechancellor@gmail.com>
> > Tested-by: Nick Desaulniers <ndesaulniers@google.com>
> > Link: https://github.com/ClangBuiltLinux/linux/issues/1099
> > ---
> > Changes in v2:
> > * Updated description to add tags and the llvm-project commit link.
> > * Fixed a typo.
>
>
> <formletter>
>
> This is not the correct way to submit patches for inclusion in the
> stable kernel tree.  Please read:
>     https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
> for how to do this properly.
>
> </formletter>
>

Hi Fangrui,

your patch needs to be accepted first in Linus tree - among other
things to have a unique commit-id for inclusion into any affected
Linux-stable trees.

Regards,
- Sedat -
Nathan Chancellor July 21, 2020, 5:13 p.m. UTC | #3 
On Tue, Jul 21, 2020 at 04:52:56PM +0200, Sedat Dilek wrote:
> On Tue, Jul 21, 2020 at 12:40 PM Greg KH <gregkh@linuxfoundation.org> wrote:
> >
> > On Mon, Jul 20, 2020 at 09:19:38PM -0700, Fangrui Song wrote:
> > > When CROSS_COMPILE is set (e.g. aarch64-linux-gnu-), if
> > > $(CROSS_COMPILE)elfedit is found at /usr/bin/aarch64-linux-gnu-elfedit,
> > > GCC_TOOLCHAIN_DIR will be set to /usr/bin/.  --prefix= will be set to
> > > /usr/bin/ and Clang as of 11 will search for both
> > > $(prefix)aarch64-linux-gnu-$needle and $(prefix)$needle.
> > >
> > > GCC searchs for $(prefix)aarch64-linux-gnu/$version/$needle,
> > > $(prefix)aarch64-linux-gnu/$needle and $(prefix)$needle. In practice,
> > > $(prefix)aarch64-linux-gnu/$needle rarely contains executables.
> > >
> > > To better model how GCC's -B/--prefix takes in effect in practice, newer
> > > Clang (since
> > > https://github.com/llvm/llvm-project/commit/3452a0d8c17f7166f479706b293caf6ac76ffd90)
> > > only searches for $(prefix)$needle. Currently it will find /usr/bin/as
> > > instead of /usr/bin/aarch64-linux-gnu-as.
> > >
> > > Set --prefix= to $(GCC_TOOLCHAIN_DIR)$(CROSS_COMPILE)
> > > (/usr/bin/aarch64-linux-gnu-) so that newer Clang can find the
> > > appropriate cross compiling GNU as (when -no-integrated-as is in
> > > effect).
> > >
> > > Reported-by: Nathan Chancellor <natechancellor@gmail.com>
> > > Signed-off-by: Fangrui Song <maskray@google.com>
> > > Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
> > > Tested-by: Nathan Chancellor <natechancellor@gmail.com>
> > > Tested-by: Nick Desaulniers <ndesaulniers@google.com>
> > > Link: https://github.com/ClangBuiltLinux/linux/issues/1099
> > > ---
> > > Changes in v2:
> > > * Updated description to add tags and the llvm-project commit link.
> > > * Fixed a typo.
> >
> >
> > <formletter>
> >
> > This is not the correct way to submit patches for inclusion in the
> > stable kernel tree.  Please read:
> >     https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
> > for how to do this properly.
> >
> > </formletter>
> >
> 
> Hi Fangrui,
> 
> your patch needs to be accepted first in Linus tree - among other
> things to have a unique commit-id for inclusion into any affected
> Linux-stable trees.
> 
> Regards,
> - Sedat -

You are not wrong but that is not what Greg's auto response is complaining
about. It is that stable@vger.kernel.org was cc'd but there was no

Cc: stable@vger.kernel.org

in the commit message, which is how patches get automatically picked up
by Greg and Sasha once they hit Linus's tree.

That line should be added above my Reported-by tag. Fangrui, sorry for
not being clear in my initial response :(

Cheers,
Nathan
Sedat Dilek July 21, 2020, 7:54 p.m. UTC | #4 
On Tue, Jul 21, 2020 at 6:20 AM 'Fangrui Song' via Clang Built Linux
<clang-built-linux@googlegroups.com> wrote:
>
> When CROSS_COMPILE is set (e.g. aarch64-linux-gnu-), if
> $(CROSS_COMPILE)elfedit is found at /usr/bin/aarch64-linux-gnu-elfedit,
> GCC_TOOLCHAIN_DIR will be set to /usr/bin/.  --prefix= will be set to
> /usr/bin/ and Clang as of 11 will search for both
> $(prefix)aarch64-linux-gnu-$needle and $(prefix)$needle.
>
> GCC searchs for $(prefix)aarch64-linux-gnu/$version/$needle,
> $(prefix)aarch64-linux-gnu/$needle and $(prefix)$needle. In practice,
> $(prefix)aarch64-linux-gnu/$needle rarely contains executables.
>
> To better model how GCC's -B/--prefix takes in effect in practice, newer
> Clang (since
> https://github.com/llvm/llvm-project/commit/3452a0d8c17f7166f479706b293caf6ac76ffd90)
> only searches for $(prefix)$needle. Currently it will find /usr/bin/as
> instead of /usr/bin/aarch64-linux-gnu-as.
>
> Set --prefix= to $(GCC_TOOLCHAIN_DIR)$(CROSS_COMPILE)
> (/usr/bin/aarch64-linux-gnu-) so that newer Clang can find the
> appropriate cross compiling GNU as (when -no-integrated-as is in
> effect).
>
> Reported-by: Nathan Chancellor <natechancellor@gmail.com>
> Signed-off-by: Fangrui Song <maskray@google.com>
> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
> Tested-by: Nathan Chancellor <natechancellor@gmail.com>
> Tested-by: Nick Desaulniers <ndesaulniers@google.com>
> Link: https://github.com/ClangBuiltLinux/linux/issues/1099
> ---
> Changes in v2:
> * Updated description to add tags and the llvm-project commit link.
> * Fixed a typo.

Tested-by: Sedat Dilek <sedat.dilek@gmail,com>

- Sedat -

> ---
>  Makefile | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/Makefile b/Makefile
> index 0b5f8538bde5..3ac83e375b61 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -567,7 +567,7 @@ ifneq ($(shell $(CC) --version 2>&1 | head -n 1 | grep clang),)
>  ifneq ($(CROSS_COMPILE),)
>  CLANG_FLAGS    += --target=$(notdir $(CROSS_COMPILE:%-=%))
>  GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE)elfedit))
> -CLANG_FLAGS    += --prefix=$(GCC_TOOLCHAIN_DIR)
> +CLANG_FLAGS    += --prefix=$(GCC_TOOLCHAIN_DIR)$(CROSS_COMPILE)
>  GCC_TOOLCHAIN  := $(realpath $(GCC_TOOLCHAIN_DIR)/..)
>  endif
>  ifneq ($(GCC_TOOLCHAIN),)
> --
> 2.28.0.rc0.105.gf9edc3c819-goog
>
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diff mbox series

Patch

diff --git a/Makefile b/Makefile
index 0b5f8538bde5..3ac83e375b61 100644
--- a/Makefile
+++ b/Makefile
@@ -567,7 +567,7 @@  ifneq ($(shell $(CC) --version 2>&1 | head -n 1 | grep clang),)
 ifneq ($(CROSS_COMPILE),)
 CLANG_FLAGS	+= --target=$(notdir $(CROSS_COMPILE:%-=%))
 GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE)elfedit))
-CLANG_FLAGS	+= --prefix=$(GCC_TOOLCHAIN_DIR)
+CLANG_FLAGS	+= --prefix=$(GCC_TOOLCHAIN_DIR)$(CROSS_COMPILE)
 GCC_TOOLCHAIN	:= $(realpath $(GCC_TOOLCHAIN_DIR)/..)
 endif
 ifneq ($(GCC_TOOLCHAIN),)