[LLVMdev] Writing LLVM front-end

[Hayden Livingston]

I'm also a beginner, so asking on this beginner thread -- is there anything
in addition to the C ABI that one needs to worry about? I imagine a C ABI
gives lots of free libraries to integrate into your language, etc.

Also the C ABI change on platforms? I thought C Calling convention was the
same on all platforms.

On Wed, Feb 18, 2015 at 9:23 AM, David Blaikie <dblaikie at gmail.com> wrote:

>
>
> On Wed, Feb 18, 2015 at 9:15 AM, Ahmed Taj elsir <meedo456123 at gmail.com>
> wrote:
>
>> Thanks you for help , David.
>>
>> Can you briefly  explain this:
>> " Most of the architecture-specific code is in LLVM, away from
>> anything you'll have to worry about.
>
>
> Most of this is in LLVM's backends - that's where things like CPU
> instruction set, register files, etc, etc, are - so your frontend doesn't
> need to know about much of that.
>
>
>> Some stuff ends up leaking up
>> into your front-end "
>>
>
> The stuff that you end up having to worry about in the frontend mostly
> relates to the ABI things I mentioned earlier - knowing that on certain
> platforms you need to put the function parameters in a certain
> order/structure so you can interoperate with existing C code, etc.
>
> If you don't need that interoperability, you don't have to worry about
> that.
>
>
>>
>> Thanks again.
>>
>>
>> On 2/18/15, David Blaikie <dblaikie at gmail.com> wrote:
>> > On Wed, Feb 18, 2015 at 8:34 AM, Ahmed Taj elsir <meedo456123 at gmail.com
>> >
>> > wrote:
>> >
>> >> Hi,
>> >>
>> >> I'm new in LLVM project , I have to write a compiler frond-end (based
>> >> on LLVM) in C++ to support my programming language .Am I have to
>> >> implement support for each architecture or LLVM has libraries  that
>> >> can do this for me ? (btw I don't want to support architecture that
>> >> LLVM don't) .
>> >>
>> >
>> > Most of the architecture-specific code is in LLVM, away from anything
>> > you'll have to worry about. Some stuff ends up leaking up into your
>> > front-end, but not much if you're starting with a simple language and
>> don't
>> > need to interoperate with existing C libraries, for example. (if your
>> > language needs to be able to call into existing C (or, worse, C++)
>> > libraries then you'll need to worry about the ABI, and that's a fair
>> amount
>> > of work/code/knowledge that needs to reside in your frontend)
>> >
>> >
>> >> does LLVM has helper functions to create objects in heap ?
>> >
>> >
>> > In your target program? No, there's not much/any help there - you just
>> call
>> > malloc/free (or op new/delete) in your LLVM IR like you would in a
>> simple C
>> > program.
>> >
>> >
>> >> if not is it good idea to use C++11 smart pointer to do memory
>> management
>> >> operations (at least in the first versions of my language ) ?
>> >>
>> >
>> > Inside your target program? You won't, presumably, have access to the
>> C++
>> > standard library in your language so you won't be able to use its
>> > convenient smart pointers. You can make your own in your new programming
>> > language, depending on what language features you have to work with.
>> >
>> > The LLVM Kaleidoscope tutorials might give you some idea of how to get
>> > started writing a compiler using LLVM.
>> >
>> > - David
>> >
>> >
>> >>
>> >> Sorry,if some questions are silly , but I'm still beginner in
>> compiler's
>> >> world .
>> >>
>> >> Thanks.
>> >> _______________________________________________
>> >> LLVM Developers mailing list
>> >> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>> >> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>> >>
>> >
>>
>
>
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