[PATCH] btrfs-progs: fix cross-compile build

[PATCH] btrfs-progs: fix cross-compile build

[Eric Sandeen]

The mktables binary needs to be build with the host
compiler at built time, not the target compiler, because
it runs at build time to generate the raid tables.

Copy auto-fu from xfsprogs and modify Makefile to
accomodate this.

Reported-by: Hallo32 <Hallo32@gmx.net>
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
---

diff --git a/Makefile b/Makefile
index b3e2b63..2647b95 100644
--- a/Makefile
+++ b/Makefile
@@ -323,7 +323,7 @@ version.h: version.sh version.h.in configure.ac
 
 mktables: kernel-lib/mktables.c
 	@echo "    [CC]     $@"
-	$(Q)$(CC) $(CFLAGS) $< -o $@
+	$(Q)$(BUILD_CC) $(BUILD_CFLAGS) $< -o $@
 
 kernel-lib/tables.c: mktables
 	@echo "    [TABLE]  $@"
diff --git a/Makefile.inc.in b/Makefile.inc.in
index 4e1b68c..0570bf8 100644
--- a/Makefile.inc.in
+++ b/Makefile.inc.in
@@ -4,6 +4,8 @@
 export
 
 CC = @CC@
+BUILD_CC = @BUILD_CC@
+BUILD_CFLAGS = @BUILD_CFLAGS@
 LN_S = @LN_S@
 AR = @AR@
 RM = @RM@
diff --git a/configure.ac b/configure.ac
index 30055f8..bc590cc 100644
--- a/configure.ac
+++ b/configure.ac
@@ -26,6 +26,23 @@ AC_CONFIG_SRCDIR([btrfs.c])
 AC_PREFIX_DEFAULT([/usr/local])
 
 AC_PROG_CC
+AC_ARG_VAR(BUILD_CC, [C compiler for build tools])
+if test "${BUILD_CC+set}" != "set"; then
+  if test $cross_compiling = no; then
+    BUILD_CC="$CC"
+  else
+    AC_CHECK_PROGS(BUILD_CC, gcc cc)
+  fi
+fi
+AC_ARG_VAR(BUILD_CFLAGS, [C compiler flags for build tools])
+if test "${BUILD_CFLAGS+set}" != "set"; then
+  if test $cross_compiling = no; then
+    BUILD_CFLAGS="$CFLAGS"
+  else
+    BUILD_CFLAGS="-g -O2"
+  fi
+fi
+
 AC_CANONICAL_HOST
 AC_C_CONST
 AC_C_VOLATILE

Re: [PATCH] btrfs-progs: fix cross-compile build

[Qu Wenruo]

On 2017年08月16日 02:11, Eric Sandeen wrote:
> The mktables binary needs to be build with the host
> compiler at built time, not the target compiler, because
> it runs at build time to generate the raid tables.
> 
> Copy auto-fu from xfsprogs and modify Makefile to
> accomodate this.
> 
> Reported-by: Hallo32 <Hallo32@gmx.net>
> Signed-off-by: Eric Sandeen <sandeen@redhat.com>

Looks better than my previous patch.
With @BUILD_CLFAGS support and better BUILD_CC/CLFAGS detection for 
native build environment.

Reviewed-by: Qu Wenruo <quwenruo.btrfs@gmx.com>

Thanks,
Qu
> ---
> 
> diff --git a/Makefile b/Makefile
> index b3e2b63..2647b95 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -323,7 +323,7 @@ version.h: version.sh version.h.in configure.ac
>   
>   mktables: kernel-lib/mktables.c
>   	@echo "    [CC]     $@"
> -	$(Q)$(CC) $(CFLAGS) $< -o $@
> +	$(Q)$(BUILD_CC) $(BUILD_CFLAGS) $< -o $@
>   
>   kernel-lib/tables.c: mktables
>   	@echo "    [TABLE]  $@"
> diff --git a/Makefile.inc.in b/Makefile.inc.in
> index 4e1b68c..0570bf8 100644
> --- a/Makefile.inc.in
> +++ b/Makefile.inc.in
> @@ -4,6 +4,8 @@
>   export
>   
>   CC = @CC@
> +BUILD_CC = @BUILD_CC@
> +BUILD_CFLAGS = @BUILD_CFLAGS@
>   LN_S = @LN_S@
>   AR = @AR@
>   RM = @RM@
> diff --git a/configure.ac b/configure.ac
> index 30055f8..bc590cc 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -26,6 +26,23 @@ AC_CONFIG_SRCDIR([btrfs.c])
>   AC_PREFIX_DEFAULT([/usr/local])
>   
>   AC_PROG_CC
> +AC_ARG_VAR(BUILD_CC, [C compiler for build tools])
> +if test "${BUILD_CC+set}" != "set"; then
> +  if test $cross_compiling = no; then
> +    BUILD_CC="$CC"
> +  else
> +    AC_CHECK_PROGS(BUILD_CC, gcc cc) > +  fi
> +fi
> +AC_ARG_VAR(BUILD_CFLAGS, [C compiler flags for build tools])
> +if test "${BUILD_CFLAGS+set}" != "set"; then
> +  if test $cross_compiling = no; then
> +    BUILD_CFLAGS="$CFLAGS"
> +  else
> +    BUILD_CFLAGS="-g -O2"
> +  fi
> +fi
> +
>   AC_CANONICAL_HOST
>   AC_C_CONST
>   AC_C_VOLATILE
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 

Re: [PATCH] btrfs-progs: fix cross-compile build

[Eric Sandeen]

On 8/15/17 7:17 PM, Qu Wenruo wrote:
> 
> 
> On 2017年08月16日 02:11, Eric Sandeen wrote:
>> The mktables binary needs to be build with the host
>> compiler at built time, not the target compiler, because
>> it runs at build time to generate the raid tables.
>>
>> Copy auto-fu from xfsprogs and modify Makefile to
>> accomodate this.
>>
>> Reported-by: Hallo32 <Hallo32@gmx.net>
>> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
> 
> Looks better than my previous patch.
> With @BUILD_CLFAGS support and better BUILD_CC/CLFAGS detection for native build environment.
> 
> Reviewed-by: Qu Wenruo <quwenruo.btrfs@gmx.com>

Thanks - and sorry for missing your earlier patch, I didn't mean to
ignore it.  :)  I just missed it.

-Eric

Re: [PATCH] btrfs-progs: fix cross-compile build

[David Sterba]

On Wed, Aug 16, 2017 at 08:17:00AM +0800, Qu Wenruo wrote:
> 
> 
> On 2017年08月16日 02:11, Eric Sandeen wrote:
> > The mktables binary needs to be build with the host
> > compiler at built time, not the target compiler, because
> > it runs at build time to generate the raid tables.
> > 
> > Copy auto-fu from xfsprogs and modify Makefile to
> > accomodate this.
> > 
> > Reported-by: Hallo32 <Hallo32@gmx.net>
> > Signed-off-by: Eric Sandeen <sandeen@redhat.com>
> 
> Looks better than my previous patch.
> With @BUILD_CLFAGS support and better BUILD_CC/CLFAGS detection for 
> native build environment.

The contents of tables.c has practially not changed since its
introduction in 2000s. I see no sense in regenerating it each time
during build and I don't want to introduce host CC build just for
this one file, standard practice or not.

Re: [PATCH] btrfs-progs: fix cross-compile build

[Qu Wenruo]

On 2017年08月25日 01:01, David Sterba wrote:
> On Wed, Aug 16, 2017 at 08:17:00AM +0800, Qu Wenruo wrote:
>>
>>
>> On 2017年08月16日 02:11, Eric Sandeen wrote:
>>> The mktables binary needs to be build with the host
>>> compiler at built time, not the target compiler, because
>>> it runs at build time to generate the raid tables.
>>>
>>> Copy auto-fu from xfsprogs and modify Makefile to
>>> accomodate this.
>>>
>>> Reported-by: Hallo32 <Hallo32@gmx.net>
>>> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
>>
>> Looks better than my previous patch.
>> With @BUILD_CLFAGS support and better BUILD_CC/CLFAGS detection for
>> native build environment.
> 
> The contents of tables.c has practially not changed since its
> introduction in 2000s. I see no sense in regenerating it each time
> during build and I don't want to introduce host CC build just for
> this one file, standard practice or not.
> 

I understand the worry about adding host CC.
But just shown by the patch, the impact is minimal.

At least for me and already mentioned before, text file managed by git 
should be reviewable.
No matter if the file get modified in 20 years or not.
(BTW, I don't think there is much problem regenerating the RAID6 table. 
It's way faster than auto-conf/auto-header things)

And I think that's the same reason other projects doesn't manage their 
generated CRC tables using git.

Thanks,
Qu

Re: [PATCH] btrfs-progs: fix cross-compile build

[Eric Sandeen]

On 8/24/17 12:01 PM, David Sterba wrote:
> On Wed, Aug 16, 2017 at 08:17:00AM +0800, Qu Wenruo wrote:
>>
>>
>> On 2017年08月16日 02:11, Eric Sandeen wrote:
>>> The mktables binary needs to be build with the host
>>> compiler at built time, not the target compiler, because
>>> it runs at build time to generate the raid tables.
>>>
>>> Copy auto-fu from xfsprogs and modify Makefile to
>>> accomodate this.
>>>
>>> Reported-by: Hallo32 <Hallo32@gmx.net>
>>> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
>>
>> Looks better than my previous patch.
>> With @BUILD_CLFAGS support and better BUILD_CC/CLFAGS detection for 
>> native build environment.
> 
> The contents of tables.c has practially not changed since its
> introduction in 2000s. I see no sense in regenerating it each time
> during build

Make does know enough to generate it only as needed, of course.

> and I don't want to introduce host CC build just for
> this one file, standard practice or not.

*shrug* it seems like the obviously correct fix to me, but I won't
fight over it.

-Eric

Re: [PATCH] btrfs-progs: fix cross-compile build

[Goffredo Baroncelli]

On 08/24/2017 07:01 PM, David Sterba wrote:
> On Wed, Aug 16, 2017 at 08:17:00AM +0800, Qu Wenruo wrote:
>>
>>
>> On 2017年08月16日 02:11, Eric Sandeen wrote:
>>> The mktables binary needs to be build with the host
>>> compiler at built time, not the target compiler, because
>>> it runs at build time to generate the raid tables.
>>>
>>> Copy auto-fu from xfsprogs and modify Makefile to
>>> accomodate this.
>>>
>>> Reported-by: Hallo32 <Hallo32@gmx.net>
>>> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
>>
>> Looks better than my previous patch.
>> With @BUILD_CLFAGS support and better BUILD_CC/CLFAGS detection for 
>> native build environment.
> 
> The contents of tables.c has practially not changed since its
> introduction in 2000s. I see no sense in regenerating it each time
> during build and I don't want to introduce host CC build just for
> this one file, standard practice or not.

I think that is a problem to have both the table generated and the mktable.c generator int git. Only one it is sufficient. Having both generate only confusion.

As my first option, I am to have only mktable in the git with BUILD_CC/CFLAGS. 
As second choice, we could remove mktable and put a comment that the tables are the kernel ones.

BTW, I suggest to put a comment in table.c to change mktable in case of update of the table. Otherwise is not obvious.

BR
G.Baroncelli

-- 
gpg @keyserver.linux.it: Goffredo Baroncelli <kreijackATinwind.it>
Key fingerprint BBF5 1610 0B64 DAC6 5F7D  17B2 0EDA 9B37 8B82 E0B5