[cfe-dev] Support a new C-like language by libclang?

[Jovi Zhangwei]

Yes, I just need C, completely don‘t need any C++ and other extension,
clang internal looks have more complexity than I need.

Do you have any guide on how to write C frontend based on LLVM? any project
can take reference other than clang? I looked into tcc before, but it seems
it's not fully C completely. actually I'm totally new to compiler, but I
really want to build that tracing tool based on bpf.

Thank you.

Jovi
 On Jan 7, 2015 5:58 PM, "Reid Kleckner" <rnk at google.com> wrote:

> If you just want C and not C++ or other language extensions, then I think
> writing your own C frontend IR is probably easier than reusing Clang's. All
> the complexity in Clang comes from C++, really, and the frontend isn't
> designed to be pluggable like the optimizer is.
>
> On Wed, Jan 7, 2015 at 5:36 PM, Jovi Zhangwei <jovi.zhangwei at gmail.com>
> wrote:
>
>> Hi,
>>
>> On Wed, Jan 7, 2015 at 4:55 PM, mats petersson <mats at planetcatfish.com>
>> wrote:
>> > And you want to DO what, exactly with it, after you have parsed it?
>> >
>> > And does your script use ALL of C's functionality?
>> >
>>
>> Some functions will be compiled to bpf bytecode and inject into
>> kernel(run in kernel), some functions
>> in one script will be compiled to x86_64 instruction which run in
>> userspace.
>>
>> (There have one project called ktap, www.ktap.org, mainly purpose for
>> kernel dynamic tracing, probably you knows systemtap,
>>  ktap is similar like systemtap. There will have a bpf backend for
>> llvm, now I'm just think how to integrating ktap and bpf)
>>
>> Some basic requirement of this new frontend is:
>> 1). support new keywords, like trace, trace_end, argstr.
>> 2). support table syntax, also multiple key table. C language don't
>> support table syntax at all.
>> 3). data structure info retrieve from debuginfo(like vmlinux), not
>> defined in script or header file.
>>
>> Do you think my design can achieve by change some part of clang(lex,
>> etc) and reuse rest library of clang? or have better solution?
>>
>> Thank you.
>>
>> > --
>> > Mats
>> >
>> > On 7 January 2015 at 23:58, Jovi Zhangwei <jovi.zhangwei at gmail.com>
>> wrote:
>> >> Hi,
>> >>
>> >> On Tue, Jan 6, 2015 at 4:16 PM, Nikola Smiljanic <popizdeh at gmail.com>
>> wrote:
>> >>> Yes, you'd have to modify clang to lex/parse/sema your
>> >>> keywords/extensions/whatever.
>> >>>
>> >>
>> >> Is there have a simple solution without change to much on clang?
>> >>
>> >> In my case, I want to parse script which have custom language based on
>> >> C. The script just like below:
>> >>
>> >> trace syscalls:*
>> >> {
>> >>     print(argstr);
>> >> }
>> >>
>> >> Actually there just have few new keywords(like trace, trace_end) in
>> >> this new language, all others in C.
>> >>
>> >> Any guide on this?
>> >>
>> >> Thank you.
>> >>
>> >>> On Wed, Jan 7, 2015 at 10:15 AM, Jovi Zhangwei <
>> jovi.zhangwei at gmail.com>
>> >>> wrote:
>> >>>>
>> >>>> Hi,
>> >>>>
>> >>>> I'm new to clang world, here I have one question about libclang or
>> >>>> libtooling, I would be very appreciate if anyone can help me.
>> >>>>
>> >>>> Currently I want to develop a new language, which is C like, just
>> some new
>> >>>> syntax sugars on top of C language, I can modify clang lexer code to
>> make
>> >>>> that, or I can use translator, but if this requirement can be done by
>> >>>> libclang or libtooling, that's perfect simple for me.
>> >>>>
>> >>>> My direct impression is there have no way to change language syntax
>> by
>> >>>> libclang/libtooling, libclang/libtooling only can parse and analysis
>> on C
>> >>>> family language, no chance to support other language by library, is
>> this
>> >>>> correct?
>> >>>>
>> >>>> Thank you.
>> >>>>
>> >>>> Jovi
>> >>>>
>> >>>> _______________________________________________
>> >>>> cfe-dev mailing list
>> >>>> cfe-dev at cs.uiuc.edu
>> >>>> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev
>> >>>>
>> >>>
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