[llvm-dev] Problems with tbaa in llvm 4.0

[Hal Finkel via llvm-dev]

[+Sanjoy]


On 01/13/2017 06:57 PM, Erik de Castro Lopo via llvm-dev wrote:
> Hi all,
>
> I do a little work on the GHC haskell compiler. One of the things I
> do is compile current GHC git HEAD against the next release of LLVM
> to find issues and adapt the GHC code as early as possible.
>
> A recent modification to LLVM is now rejecting GHC generated LLVM
> IR that was previously accepted. I discussed this on IRC with
> sanjoyd who explained what had changed and gave me some hints about
> trying to fix it. Basically the issue (as I understood it) was that
> no statements should reference the root tbaa node directly.
>
> With that in mind, I came up with a fix to GHC llvm codegen so the
> the tbaa metadata is now:
>
>      !0 = !{!"root", null}
>      !1 = !{!"top", !0}
>      !2 = !{!"stack", !1}
>      !3 = !{!"heap", !1}
>      !4 = !{!"rx", !3}
>      !5 = !{!"base", !1}
>
> However, with this fix I get basically the same set of error messages
> A couple of the errors are:
>
>      Access type node must be a valid scalar type
>        %ln59 = load i64, i64* %ln58, !tbaa !6
>      !6 = !{!2, !2, i64 0}
>      !2 = !{!"top", !3}
>
>      Access type node must be a valid scalar type
>        %ln5d = load i64, i64* %ln5c, !tbaa !4
>      !4 = !{!5, !5, i64 0}
>      !5 = !{!"base", !2}
>
>      Access type node must be a valid scalar type
>        %ln5i = load i64, i64* %ln5h, !tbaa !0
>      !0 = !{!1, !1, i64 0}
>      !1 = !{!"stack", !2}
>
> I would appreciate any clues that might help me solve this.
>
> Cheers,
> Erik

-- 
Hal Finkel
Lead, Compiler Technology and Programming Languages
Leadership Computing Facility
Argonne National Laboratory