Re: [PATCH v15 7/7] perf: Add more features to supported_features list

[Aditya Gupta <adityag@linux.ibm.com>]

On 05/09/24 01:32, Arnaldo Carvalho de Melo wrote:

> On Thu, Sep 05, 2024 at 12:31:32AM +0530, Aditya Gupta wrote:
>> As suggested in [1], add more feature names and corresponding names,
>> based on the information in Makefile.config
>>
>> The entries were added after seeing the corresponding -D option which is
>> added to CFLAGS, based on the presence of a feature in Makefile.config,
>> such as:
>>
>>      ifeq ($(feature-file-handle), 1)
>>        CFLAGS += -DHAVE_FILE_HANDLE
>>      endif
>>
>> For above feature 'file-handle', corresponding entry has been added to
>> supported_features as below:
>>
>>      FEATURE_STATUS("file-handle", HAVE_FILE_HANDLE)
>>
>> [1]: https://lore.kernel.org/linux-perf-users/Zn7EvDbsnlbLXj4g@x1/
> I'll remove this now because there were some that sounds really strange,
> like:
Okay.
> acme@x1:~/git/perf-tools-next$ sudo su -
> [sudo] password for acme:
> root@x1:~# perf -vv
> perf version 6.11.rc3.g15dc9f274b8e
>                   glibc: [ OFF ]  # LIBC_SUPPORT
> libslang-include-subdir: [ OFF ]  # HAVE_SLANG_INCLUDE_SUBDIR
>
>
> The first one is the strange one, how come, no LIBC_SUPPORT? glibc?
Debugged it:


Output of `make` says glibc is there:


     Auto-detecting system features:

     ...                                   ...

     ...                                   glibc: [ on  ]

     ...                                   ...

     ...                                  libelf: [ on  ]


But, in Makefile.config, 'LIBC_SUPPORT' is only defined if libelf is NOT 
there:


     ifeq ($(feature-libelf), 0)
         ifeq ($(feature-glibc), 1)
             LIBC_SUPPORT := 1
         endif
      ifeq ($(BIONIC),1)
           LIBC_SUPPORT := 1
       endif


Hence since LIBC_SUPPORT is not defined, the check --feature command 
says glibc is OFF.

I think we can simply remove libc entry from the features array in this 
patch, as glibc is kind of obvious to be there if compilation worked.


Meanwhile I will check all feature entries added in this patch again. I 
can post this patch as an independent patch.


> The second looks irrelevant, I'll see.

Sure.


Thanks,

Aditya Gupta

>
> - Arnaldo