[llvm-dev] A libc in LLVM

Wed Sep 18 23:49:37 PDT 2019

Hi,

What happened since you committed the doc? Is this now graduated from a
"proposal to start a project" to a project?
Is there any update to be made to the doc:
http://llvm.org/docs//Proposals/LLVMLibC.html ?

Thanks,

-- 
Mehdi

On Mon, Sep 16, 2019 at 3:05 PM Siva Chandra via llvm-dev <
llvm-dev at lists.llvm.org> wrote:

> Hello again,
>
> I would like to announce that we now have dedicated mailing lists for the
> llvm-libc project:
>
> 1. libc-dev - https://lists.llvm.org/cgi-bin/mailman/listinfo/libc-dev
> 2. libc-commits -
> https://lists.llvm.org/cgi-bin/mailman/listinfo/libc-commits
>
> A brief README.txt and LICENSE.txt have been added:
> https://github.com/llvm/llvm-project/tree/master/libc
>
> I will soon share or put out design docs and code for review, as suitable.
>
> Thanks,
> Siva Chandra
>
> On Thu, Aug 15, 2019 at 11:23 AM Siva Chandra <sivachandra at google.com>
> wrote:
>
>> Hello again,
>>
>> I have now committed a proposal for this new libc:
>> https://reviews.llvm.org/D64939. This proposal is based on the charter
>> I shared previously (see below).
>>
>> Though it is now committed, if there are any concerns still, I am open
>> to iterating until the community in general is satisfied with the
>> proposal.
>>
>> Thanks,
>> Siva Chandra
>>
>> On Fri, Jul 12, 2019 at 8:15 AM Siva Chandra <sivachandra at google.com>
>> wrote:
>> > "llvm-libc" C Standard Library
>> > ========================
>> >
>> > llvm-libc is an implementation of the C standard library targeting C11
>> > and above. It also provides platform specific extensions as relevant.
>> > For example, on Linux it also provides pthreads, librt and other POSIX
>> > extension libraries.
>> >
>> > Documentation
>> > ============
>> >
>> > The llvm-libc project is still in the planning phase. Stay tuned for
>> > updates soon.
>> >
>> > Features and Goals
>> > ================
>> >
>> > * C11 and upwards conformant.
>> > * A modular libc with individual pieces implemented in the "as a
>> > library" philosophy of the LLVM project.
>> > * Ability to layer this libc over the system libc.
>> > * Provide C symbols as specified by the standards, but take advantage
>> > and use C++ language facilities for the core implementation.
>> > * Provides POSIX extensions on POSIX compliant platforms.
>> > * Provides system-specific extensions as appropriate. For example,
>> > provides the Linux API on Linux.
>> > * Vendor extensions if and only if necessary.
>> > * Designed and developed from the start to work with LLVM tooling and
>> > testing like fuzz testing and sanitizer-supported testing.
>> > * ABI independent implementation as far as possible.
>> > * Use source based implementations as far possible rather than
>> > assembly. Will try to “fix” the compiler rather than use assembly
>> > language workarounds.
>> >
>> > Why a new C Standard Library?
>> > =========================
>> >
>> > Implementing a libc is no small task and is not be taken lightly. A
>> > natural question to ask is, "why a new implementation of the C
>> > standard library?" There is no single answer to this question, but
>> > some of the major reasons are as follows:
>> >
>> > * Most libc implementations are monolithic. It is a non-trivial
>> > porting task to pick and choose only the pieces relevant to one's
>> > platform. The new libc will be developed with sufficient modularity to
>> > make picking and choosing a straightforward task.
>> > * Most libc implementations break when built with sanitizer specific
>> > compiler options. The new libc will be developed from the start to
>> > work with those specialized compiler options.
>> > * The new libc will be developed to support and employ fuzz testing
>> > from the start.
>> > * Most libc implementations use a good amount of assembly language,
>> > and assume specific ABIs (may be platform dependent). With the new
>> > libc implementation, we want to use normal source code as much as
>> > possible so that compiler-based changes to the ABI are easy. Moreover,
>> > as part of the LLVM project, we want to use this opportunity to fix
>> > performance related compiler bugs rather than using assembly
>> > workarounds.
>> > * A large hole in the llvm toolchain will be plugged with this new
>> > libc. With the broad platform expertise in the LLVM community, and the
>> > strong license and project structure, we think that the new libc will
>> > be more tunable and robust, without sacrificing the simplicity and
>> > accessibility typical of the LLVM project.
>> >
>> > Platform Support
>> > ==============
>> >
>> > llvm-libc development is still in the planning phase. However, we
>> > envision that it will support a variety of platforms in the coming
>> > years. Interested parties are encouraged to participate in the design
>> > and implementation, and add support for their favorite platforms.
>> >
>> > Current Status
>> > ============
>> >
>> > llvm-libc development is still in the planning phase.
>> >
>> > Build Bots
>> > =========
>> >
>> > Coming soon.
>> >
>> > Get involved!
>> > ===========
>> >
>> > First please review our Developer's Policy. Stay tuned for llvm-libc
>> > specific information.
>> >
>> > Design Documents
>> > ===============
>> >
>> > Coming soon.
>>
> _______________________________________________
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>
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