[llvm-dev] question about xray tls data initialization

[comic fans via llvm-dev]

I wonder if I can build xray with clang/llvm-as on windows, seems that
is a little easier and requires less changes. but I've not tried yet.

On Fri, Nov 24, 2017 at 8:22 AM, Dean Michael Berris
<dean.berris at gmail.com> wrote:
>
> On 23 Nov 2017, at 23:34, comic fans <comicfans44 at gmail.com> wrote:
>
> On Wed, Nov 22, 2017 at 10:37 AM, Dean Michael Berris
> <dean.berris at gmail.com> wrote:
>
>
> On 22 Nov 2017, at 02:32, comic fans <comicfans44 at gmail.com> wrote:
>
> with some dirty hack , I've made xray runtime  'built' on windows ,
>
>
> \o/
>
>
> with more test, I've found that trampoline didn't got built for windows :/
> currently cmake didn't generate build rule for asm so its silently
> ignored(with msvc ide, but not ninja).
> we must have enable_language(ASM_MASM) to use masm, and trampoline
> also need ports.
>
>
> Right -- this is similar to issues we've run into trying to make XRay work /
> get built for Darwin too.
>
>
> If you're alright with it, maybe you can send some patches to review,
> preferably through the LLVM Phabricator instance? You can have me or Reid
> (who knows more about COFF and the Windows stuff) as reviewers.
>
> in AsmPrinter, copy/paster xray for coff target
>
> InstMap = OutContext.getCOFFSection("xray_instr_map", 0,
> SectionKind::getReadOnlyWithRel());
> FnSledIndex = OutContext.getCOFFSection("xray_fn_idx",
> 0,SectionKind::getReadOnlyWithRel());
>
> in XRayArgs , allow windows platform to use xray args. with this,
> generated code seems have sled and xray parts.
>
>
> Nice, I suspect we can make this change with tests as well, which we can
> build on incrementally.
>
>
> where can I find some examples to test this xray part in llvm ?
>
>
> Those are in the llvm/test/CodeGen/X86/... -- in particular, searching for
> 'xray_' in the files there will be the best way of finding examples of what
> we're looking for to verify.
>
>
> in xray runtime,
> bool atomic_compare_exchange_strong(volatile atomic_sint32_t *a,
>                                          s32 *cmp,
>                                          s32 xchg,
>                                          memory_order mo)
> is missed for MSVC , I take atomic_uint32_t implementation
>
>
> This is in compiler-rt/lib/sanitizer_common/... right?
>
>
> yes, sanitizer_atomic_msvc.h didn't provide this override. according
> to msdn of interlockedcompareexchange,  implementation for
> atomic_uint32_t should also works for atomic_sint32_t. this is a
> copy/paste but I think its short enough. any better suggestion ?
>
>
> I'm sure adding an implementation for atomic_sint32_t will be nice to have
> across platforms. :)
>
>
> FunctionRecord pack , __attribute__((packed)) =>  #pragma
> pack(push,1),  msvc also requires bitfields to be same type to pack
> them together( all types => uint32_t)
>
>
> Are you able to test this on other platforms?
>
>
> I've tested this on linux64 (with clang) and it pass check-xray , but
> I don't have mac to test. if changing all attribute to pragma is
> desirable , I can submit a patch for that .
>
>
> We're still working on getting XRay to build right and work on macOS so that
> shouldn't be a barrier. :)
>
> A patch would be good there too.
>
> Thanks again!
>
> -- Dean
>