[llvm-dev] RFC: Move parts of llvm-symbolizer tool implementation to LLVMSymbolize library

[Alexey Samsonov via llvm-dev]

We have out-of-tree implementation of llvm-symbolizer-as-a-library, and I
still hope to upstream it one day (unfortunately, its build process is
really complicated).

Mike can probably comment on his plans for using symbolization in
coverage-related tools.

On Wed, Oct 21, 2015 at 11:34 AM, Eric Christopher <echristo at gmail.com>
wrote:

> To create unit tests is a pretty good reason IMO :)
>
> That said, I'd be a fan of trying to encapsulate all of this behind an
> interface. I like that most of the tools are exceptionally light weight and
> it makes it much more obvious what's "wrapper" versus "functionality" in
> something like llvm-symbolize. That said, I'll be interested to see the
> library design :)
>

Do you suggest to design it upfront, or you're fine with moving the
existing code first, and gradually updating the interface afterwards?


>
> -eric
>
> On Wed, Oct 21, 2015 at 7:35 AM Rafael Espíndola <llvm-dev at lists.llvm.org>
> wrote:
>
>> I would say it is worth it if someone is actually planning on using
>> the library in something else.
>>
>> Moving the code "just in case" or to create unit tests is not a good
>> reason IMHO.
>>
>> On 20 October 2015 at 16:54, Alexey Samsonov <vonosmas at gmail.com> wrote:
>> > Hi,
>> >
>> > We have a lot of non-trivial logic accumulated in the
>> > implementation of llvm-symbolizer tool
>> > (tools/llvm-symbolizer/LLVMSymbolize.{h,cpp}), for instance:
>> >
>> > * dynamic dispatch between DWARF and PDB debug info;
>> > * building address->symbol_name mapping from object file (with special
>> cases
>> > for PowerPC function descriptor section, and COFF export tables);
>> > * finding debug info stored in separate files (.dSYM files on Darwin,
>> ELF
>> > .gnu_debuglink section, etc.);
>> > * demangling (with platform-specific implementations for Windows and
>> Unix).
>> >
>> > I propose to move this code into a separate library LLVMSymbolize
>> (stored
>> > under lib/DebugInfo/Symbolize), and make llvm-symbolizer a short and
>> simple
>> > tool using it. This would allow to:
>> >
>> > * implement in-process symbolized stack trace printers (for the cases
>> when
>> > it's possible to link in a bunch of LLVM libraries into the executable).
>> > * easily write more tools that can make use of symbolized code
>> locations,
>> > such as coverage data visualizers.
>> > * (at least sometimes) write unit tests instead of testing
>> functionality by
>> > running "llvm-symbolizer" executable on pre-built executables checked in
>> > repository.
>> >
>> > Any comments/objections?
>> >
>> > --
>> > Alexey Samsonov
>> > vonosmas at gmail.com
>> _______________________________________________
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org
>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>
>


-- 
Alexey Samsonov
vonosmas at gmail.com
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