[LLVMdev] unwind's permanent residence

[Nick Kledzik]

On Feb 3, 2015, at 4:07 AM, Renato Golin <renato.golin at linaro.org> wrote:

> On 30 January 2015 at 20:43, Jonathan Roelofs <jonathan at codesourcery.com> wrote:
>> Last time we brought this up, there was only partial consensus, and then
>> someone arbitrarily declared total consensus (without compelling arguments
>> in any particular direction) that we were going to move it to compiler_rt.
>> Then the discussion fell on the floor because no-one had time to actually do
>> the move. Please, let's not let that happen again this time.
> 
> So, do we have a consensus?
> 
> AFAICS, the most agree solution (with optionals to be defined):
> 
> 1. Move Unwinder to its own repository in the LLVM server
This is fine with me.  But I thought when I first submitted the source there was push back because we “already have too many repositories”.

> 2. Make the CMake connections from libc++abi and compiler-rt
>  2.1 OPTIONAL 1: err if libunwinder is not there, clang errs if rtlib=RT
>  2.2 OPTIONAL 2: warns if libunwind is not there, clang errs if rtlib=RT
>  2.3 OPTIONAL 3: nothing, make clang smarter to pick existing unwinder
> 3. Change clang to assume -lunwind when --rtlib=compiler-rt
>  3.1 OPTIONAL 4: allow linker error if no -lunwind / -lgcc_s
>  3.2 OPTIONAL 5: Add option to change unwinder library by not adding
> -lunwind/-lgcc_s, but whatever comes as argument
I assume these are all just about ELF platforms.  Darwin does not need any of this logic.

-Nick 


> 
> 1, 2, and 3 must be changed.
> 
> I vote for adding { 2.2, 3.1 } for now, { 2.2, 3.1, 3.2 } for later.
> 
> My idea for 3.2 is something like --unwinder=libgcc_s / libunwind, or
> something like that.
> 
> I personally don't think the front-end scanning existing libraries is
> a good thing to do, but I'm not against the idea, if anyone feels
> strongly about it.
> 
> If all of us could agree to a common solution, and make sure all
> interested parties are in, we should do the move before 3.7.
> 
> Please, cast your votes.
> 
> cheers,
> --renato