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Date:   Wed, 24 Aug 2022 14:15:36 -0300
From:   Arnaldo Carvalho de Melo <acme@kernel.org>
To:     Nathan Chancellor <nathan@kernel.org>
Cc:     dwarves@vger.kernel.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Alibek Omarov <a1ba.omarov@gmail.com>,
        Kornilios Kourtis <kornilios@isovalent.com>,
        Kui-Feng Lee <kuifeng@fb.com>, Yonghong Song <yhs@fb.com>,
        bpf@vger.kernel.org, Jiri Olsa <jolsa@kernel.org>
Subject: Re: ANNOUNCE: pahole v1.24 (Faster BTF encoding, 64-bit BTF enum
 entries)
Message-ID: <YwZcuCj49wMkr18W@kernel.org>
References: <YwQRKkmWqsf/Du6A@kernel.org>
 <YwZQ0UkLsoa+6VyY@dev-arch.thelio-3990X>
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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