Re: ANNOUNCE: pahole v1.24 (Faster BTF encoding, 64-bit BTF enum entries)

[Luna Jernberg]

Great :)

On 8/24/22, Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> wrote:
> Em Wed, Aug 24, 2022 at 09:24:49AM -0700, Nathan Chancellor escreveu:
>> Hi Arnaldo,
>>
>> On Mon, Aug 22, 2022 at 08:28:42PM -0300, Arnaldo Carvalho de Melo wrote:
>> > Hi,
>> >
>> > 	The v1.24 release of pahole and its friends is out, with faster
>> > BTF generation by parallelizing the encoding part in addition to the
>> > previoulsy parallelized DWARF loading, support for 64-bit BTF
>> > enumeration
>> > entries, signed BTF encoding of 'char', exclude/select DWARF loading
>> > based on the language that generated the objects, etc.
>>
>> <snip>
>>
>> > - Introduce --lang and --lang_exclude to specify the language the
>> >   DWARF compile units were originated from to use or filter.
>>
>> This appears to break building pahole with older versions of libdw (?).
>> I build container images with older versions of compilers for easy
>> matrix testing and my gcc-5 and gcc-6 images (based off Ubuntu Xenial
>> and Debian Stretch respectively) fail to build.
>
> I do it for perf, should have done it for pahole :-\
>
> So I'll have to come up with a patch that checks if those are defined
> and if not, define it :-\ Ooops, its an enumeration :-\ I'll have to
> check how to fix this, thanks for the report!
>
> Will rebuild it with the containers I have to see if there are other
> cases.
>
> - Arnaldo
>
>>     $ podman run --rm -ti -v
>> $TMP_FOLDER/dwarves-1.24.tar.xz:/tmp/dwarves-1.24.tar.xz:ro
>> docker.io/ubuntu:xenial
>>     # apt update
>>     # apt install build-essential cmake libdw-dev libelf-dev xz-utils
>> zlib1g-dev
>>     # cd $(mktemp -d)
>>     # tar -xJf /tmp/dwarves-1.24.tar.xz
>>     # mkdir build
>>     # cd build
>>     # cmake -DBUILD_SHARED_LIBS=OFF -D__LIB=lib ../dwarves-1.24
>>     # make -j$(nproc)
>>     ...
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c: In function
>> 'lang__str2int':
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2093:3: error:
>> 'DW_LANG_BLISS' undeclared (first use in this function)
>>       [DW_LANG_BLISS]   = "bliss",
>>        ^
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2093:3: note: each
>> undeclared identifier is reported only once for each function it appears
>> in
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2093:3: error: array index
>> in initializer not of integer type
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2093:3: note: (near
>> initialization for 'languages')
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2100:3: error:
>> 'DW_LANG_C_plus_plus_03' undeclared (first use in this function)
>>       [DW_LANG_C_plus_plus_03] = "c++03",
>>        ^
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2100:3: error: array index
>> in initializer not of integer type
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2100:3: note: (near
>> initialization for 'languages')
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2105:3: error:
>> 'DW_LANG_Dylan' undeclared (first use in this function)
>>       [DW_LANG_Dylan]   = "dylan",
>>        ^
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2105:3: error: array index
>> in initializer not of integer type
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2105:3: note: (near
>> initialization for 'languages')
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2114:3: error:
>> 'DW_LANG_Julia' undeclared (first use in this function)
>>       [DW_LANG_Julia]   = "julia",
>>        ^
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2114:3: error: array index
>> in initializer not of integer type
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2114:3: note: (near
>> initialization for 'languages')
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2116:3: error:
>> 'DW_LANG_Modula3' undeclared (first use in this function)
>>       [DW_LANG_Modula3]  = "modula3",
>>        ^
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2116:3: error: array index
>> in initializer not of integer type
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2116:3: note: (near
>> initialization for 'languages')
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2119:3: error:
>> 'DW_LANG_OCaml' undeclared (first use in this function)
>>       [DW_LANG_OCaml]   = "ocaml",
>>        ^
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2119:3: error: array index
>> in initializer not of integer type
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2119:3: note: (near
>> initialization for 'languages')
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2120:3: error:
>> 'DW_LANG_OpenCL' undeclared (first use in this function)
>>       [DW_LANG_OpenCL]  = "opencl",
>>        ^
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2120:3: error: array index
>> in initializer not of integer type
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2120:3: note: (near
>> initialization for 'languages')
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2122:3: error:
>> 'DW_LANG_PLI' undeclared (first use in this function)
>>       [DW_LANG_PLI]   = "pli",
>>        ^
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2122:3: error: array index
>> in initializer not of integer type
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2122:3: note: (near
>> initialization for 'languages')
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2124:3: error:
>> 'DW_LANG_RenderScript' undeclared (first use in this function)
>>       [DW_LANG_RenderScript]  = "renderscript",
>>        ^
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2124:3: error: array index
>> in initializer not of integer type
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2124:3: note: (near
>> initialization for 'languages')
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2125:3: error:
>> 'DW_LANG_Rust' undeclared (first use in this function)
>>       [DW_LANG_Rust]   = "rust",
>>        ^
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2125:3: error: array index
>> in initializer not of integer type
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2125:3: note: (near
>> initialization for 'languages')
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2126:3: error:
>> 'DW_LANG_Swift' undeclared (first use in this function)
>>       [DW_LANG_Swift]   = "swift",
>>        ^
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2126:3: error: array index
>> in initializer not of integer type
>>     /tmp/tmp.pQ2GsHbGAx/dwarves-1.24/dwarves.c:2126:3: note: (near
>> initialization for 'languages')
>>     CMakeFiles/dwarves.dir/build.make:62: recipe for target
>> 'CMakeFiles/dwarves.dir/dwarves.c.o' failed
>>     ...
>>
>> If there is any additional information I can provide or patches I can
>> test, please let me know!
>>
>> Cheers,
>> Nathan
>
> --
>
> - Arnaldo
>