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Re: libgo patch committed: Implement reflect.MakeFunc for 386

On Mon, Sep 30, 2013 at 7:07 AM, Rainer Orth
<> wrote:
> Ian Lance Taylor <> writes:
>> On Mon, Sep 30, 2013 at 6:07 AM, Rainer Orth
>> <> wrote:
>>> Ian Lance Taylor <> writes:
>>>> Following up on my earlier patch, this patch implements the
>>>> reflect.MakeFunc function for 386.
>>>> Tom Tromey pointed out to me that the libffi closure support can
>>>> probably be used for this.  I was not aware of that support.  It
>>>> supports a lot more processors, and I should probably start using it.
>>>> The approach I am using does have a couple of advantages: it's more
>>>> efficient, and it doesn't require any type of writable executable
>>>> memory.  I can get away with that because indirect calls in Go always
>>>> pass a closure value.  So even when and if I do change to using libffi,
>>>> I might still keep this code for amd64 and 386.
>>> Unfortunately, this patch (and undoubtedly the corresponding amd64 one)
>>> break Solaris/x86 libgo bootstrap with native as:
>> Unfortunately I think I'll have to somehow disable this functionality
>> on systems with assemblers that do not understand the .cfi directives,
>> as otherwise calling panic in a function created with MakeFunc will
>> not work.
> Alternatively, one could hand-craft the .eh_frame section for such
> systems along the lines of libffi/src/x86/sysv.S: ugly, but doable.

Yeah.  I'm not going to do that myself.  But I would be happy to
approve a patch for that if somebody else wants to write it.


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