[PATCH] readelf: objdump: sframe: fix dumping with section name

[Indu Bhagat]

On 7/20/25 10:46 PM, Jan Beulich wrote:
> On 20.07.2025 07:34, Indu Bhagat via Binutils wrote:
>> Fix PR binutils/33186 - No SFrame dump if section name is not .sframe
>>
>> When no section name is given, ensure that the dumping routines are able
>> to dump a section of type SHT_GNU_SFRAME and not fail if the SFrame
>> section name is not ".sframe".
>>
>> For objdump, in dump_dwarf_section (), use the match string of ".sframe"
>> to find the corresponding debug_displays[] item for SFrame section.
>> Doing this ensures that any call to dump_dwarf_section () with the
>> section pointing to the SFrame section (with name possibly different
>> from ".sframe") will successfully dump the SFrame section.
>>
>> If the SFrame section is named anything but ".sframe", the desirable
>> behaviour is:
>>
>> $ readelf -S sort | grep sframe
>>    [NN] .sframe2          GNU_SFRAME       0000000000NNNNNN  0000NNNN
>> $ objdump --sframe sort
>>
>> sort:     file format elf64-x86-64
>>
>> No .sframe section present
>>
>> So, set dump_sframe_section_name to ".sframe" if user specifies no
>> section name.  In the error checking done in dump_sframe_section, add
>> the case when user specifies a valid section name but one that does not
>> contain SFrame section data.
>>
>> Similar changes in readelf.
>>
>> Add a test each for objdump and readelf to dump a renamed section.  Use
>> gas_sframe_check to limit the execution of these tests only when a gas
>> supporting SFrame format is present.
>>
>> binutils/
>> 	PR binutils/33186
>> 	* objdump.c (dump_dwarf_section): Set match to ".sframe" which
>> 	corresponds to the name in the debug_displays[] entry for
>> 	SFrame section.
>> 	(dump_sframe_section): Check if the user specified section name
>> 	contains SFrame data.
>> 	(main): Set default section name to ".sframe".
>> 	* readelf.c (display_debug_section): Adjust checks to find the
>> 	debug_diplay[] item for the input SFrame section in the arg.
>> binutils/testsuite/
>> 	PR binutils/33186
>> 	* binutils-all/x86-64/objdump-sframe-01.d: New test.
>> 	* binutils-all/x86-64/readelf-sframe-01.d: New test.
>> 	* binutils-all/x86-64/sframe-func.s: New test.
>>
>> ----
>>
>> After the patch:
>>
>> $ objcopy --rename-section .sframe=.sframe2 sort
>> $ $ readelf -S sort | grep sframe
>>    [NN] .sframe2          GNU_SFRAME       0000000000NNNNNN  0000NNNN
>>
>> $ readelf  --sframe=.sframe sort
>> readelf: Warning: Section '.sframe' was not dumped because it does not exist
>> $ readelf  --sframe sort
>> readelf: Warning: Section '.sframe' was not dumped because it does not exist
> 
> Is this and ...
> 
>> $ readelf  --sframe=.sframe2 sort
>> Contents of the SFrame section .sframe2:
>>    Header :
>>
>>      Version: SFRAME_VERSION_2
>>     ...
>> $ readelf  --sframe=.ctf sort
>> Unrecognized debug section: .ctf
>>
>> $ objdump  --sframe=.sframe sort
>> No .sframe section present
>> $ objdump  --sframe sort
>> No .sframe section present
> 
> ... this really what is wanted? Shouldn't plain --sframe dump any GNU_SFRAME
> sections, no matter what their names? (IOW there may want to be further test
> cases covering the situation with more than one GNU_SFRAME section in an
> object file.)
> 

This is, for now, in alignment with the intention.  The options text 
communicated so far:

$ objdump --help | grep sframe
       --sframe[=SECTION]   Display SFrame info from SECTION, (default 
'.sframe')

$ readelf --help | grep sframe
   --sframe[=NAME]        Display SFrame info from section NAME, 
(default '.sframe')

At this time, I dont see a usecase for multiple GNU_SFRAME sections 
(further, for ET_DYN, ET_EXEC, there will be just one GNU_SFRAME section).