Hi, Thank you all so much. But even after I read the Genode documentation, it is still very unclear to me how to support C++ in a new OS. I am confusing about the relationship among gcc, C library and OS. It seems that gcc uses some its internal libraries to implement some C++ support, for example libgcc contains the unwinder for exceptions and libsupc++. And those internal libraries depend on C library and OS support. Is my understanding of gcc is correct? If sel4 now does not fully support C++, is there any microkernels or "small" OS support C++? So I can learn some experience from it. Thanks again. Yuxin On Sat, Jun 20, 2015 at 2:26 PM, da Tyga wrote:

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Hi Yuxin,

I don't think you need to modify GCC, it is the compiler that you can use to generate required executables. Making changes to it is a massive undertaking.

Instead of trying to reinvent stuff that has already been done, you really should read the Genode documentation and download and read the source code referenced by Norman Feske's suggestions.

From my reading of the Genode documents and source code, I would expect that you would find a considerable amount of code that you could you re-purpose for your specific requirements.

Cheers, Tyga

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Message: 1 Date: Fri, 19 Jun 2015 22:46:40 +0800 From: Yuxin Ren To: Norman Feske Cc: "devel@sel4.systems" Subject: Re: [seL4] Does sel4 support c++ Message-ID: Content-Type: text/plain; charset="utf-8"

Thank you all!

If modifying the tool chain is the easiest way, I want to try it. But I definitely want to avoid creating the tool chain from "bare metal". I still prefer to reuse the existing tool chain like gcc with minimal modification.

Could you give me some guidance how to create a custom tool chain, which part I need to modify? I am not familiar with gcc. So if I have to modify gcc, where can I get more information or documentation?

Thanks a lot!! Yuxin

On Thu, Jun 18, 2015 at 9:50 PM, Norman Feske < norman.feske@genode-labs.com> wrote:

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Hello,

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The easiest approach is possibly to create a custom tool chain, and port the GCC C++ library that way. I know the people behind Genode did some of this (http://genode.org/download/tool-chain), although I'm not sure how much of the C++ standard library they actually support.

more in-depth information about Genode's tool chain are provided by Section 7.2 of the documentation [1]. In short, the tool chain is a "bare metal" tool chain that does not depend on a C library, yet it still supports C++ (including exceptions and runtime type information).

On Genode, the libc and STL (aka stdcxx) can be used optionally whereas the STL depends on the libc. The libc is based on FreeBSD's libc. The STL is GCC's version. Both libraries are available via Genode's ports mechanism.

That said, as both the libc and stdcxx are shared libraries, they cannot be used on the seL4 version of Genode as of now. Shared libraries don't work on seL4 (at least on x86_32) because the system-call bindings cannot be compiled with -fPIC.

[1] http://genode.org/documentation/genode-foundations-15-05.pdf

Best regards Norman

-- Dr.-Ing. Norman Feske Genode Labs

http://www.genode-labs.com ? http://genode.org

Genode Labs GmbH ? Amtsgericht Dresden ? HRB 28424 ? Sitz Dresden Gesch?ftsf?hrer: Dr.-Ing. Norman Feske, Christian Helmuth

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