Re: [PATCH v9 04/10] configure: Generate rule to calculate the base architecture of a target

[Philippe Mathieu-Daudé]

On 6/23/20 10:01 AM, Claudio Fontana wrote:
> Hi Philippe, Alex,
> 
> On 6/18/20 2:33 PM, Philippe Mathieu-Daudé wrote:
>> From: Alex Bennée <alex.bennee@linaro.org>
>>
>> As we encode the base architecture in configure.sh, we can emit
>> the base-arch() function into config-host.mak.
>>
>> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
>> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> 
> I found this change a bit strange, but maybe I am missing some context.

This is used in patch 9:
"Makefile: Allow target-specific optional Kconfig"
https://www.mail-archive.com/qemu-devel@nongnu.org/msg713823.html

> 
> Would it not be easier to read the information from the
> config-target.mak files as it is already emitted there?

So you are suggesting moving the SUBDIR_DEVICES_MAK creation code
to Makefile.target, before until now it is target-agnostic but we
are making it target-specific. Yes, it could work...

I keep respining this series since the semihosting rework. Frankly
I don't remember why it became so complicated, I need to jump into
the code again.

I guess when Paolo introduced Kconfig, the accelerator configs were
almost static, so SUBDIR_DEVICES_MAK was only dependent of host
config.

The semihosting "device" depends of accelerator and target configs.

Maybe the problem is to see minikconf generating device selectors,
as kconfig is also used for generic features (such accelerator,
not really "device").

> 
> Ciao,
> 
> Claudio
> 
> 
>> ---
>>  configure | 19 +++++++++++++++++++
>>  1 file changed, 19 insertions(+)
>>
>> diff --git a/configure b/configure
>> index ba88fd1824..c0d7fbc30e 100755
>> --- a/configure
>> +++ b/configure
>> @@ -7927,6 +7927,8 @@ if test "$linux" = "yes" ; then
>>      fi
>>  fi
>>  
>> +target_to_base_map=""
>> +
>>  for target in $target_list; do
>>  target_dir="$target"
>>  config_target_mak=$target_dir/config-target.mak
>> @@ -8155,6 +8157,7 @@ target_arch_name="$(upper $TARGET_ARCH)"
>>  echo "TARGET_$target_arch_name=y" >> $config_target_mak
>>  echo "TARGET_NAME=$target_name" >> $config_target_mak
>>  echo "TARGET_BASE_ARCH=$TARGET_BASE_ARCH" >> $config_target_mak
>> +target_to_base_map="$target_dir,$TARGET_BASE_ARCH $target_to_base_map"
>>  if [ "$TARGET_ABI_DIR" = "" ]; then
>>    TARGET_ABI_DIR=$TARGET_ARCH
>>  fi
>> @@ -8370,6 +8373,22 @@ if test "$ccache_cpp2" = "yes"; then
>>    echo "export CCACHE_CPP2=y" >> $config_host_mak
>>  fi
>>  
>> +# Export a rule for calculating base arch from target_dir for use by
>> +# the Kconfig generator
>> +echo "# Usage: \$(call base-arch, target-dir)" >> $config_host_mak
>> +echo "# Return the base architecture for a target." >> $config_host_mak
>> +echo "# e.g \$(call base-arch, aarch64-linux-user) returns 'arm'" >> 
>> $config_host_mak
>> +echo "base-arch = \$(strip \\" >> $config_host_mak
>> +close_braces=""
>> +for pairs in $target_to_base_map
>> +do
>> +    dir="${pairs%%,*}"
>> +    base="${pairs#*,}"
>> +    echo "\$(if \$(findstring $dir,\$1),$base, \\" >> $config_host_mak
>> +    close_braces="$close_braces )"
>> +done
>> +echo "$close_braces )" >> $config_host_mak
>> +
>>  # If we're using a separate build tree, set it up now.
>>  # DIRS are directories which we simply mkdir in the build tree;
>>  # LINKS are things to symlink back into the source tree
>>
>