[llvm-dev] Problems with tbaa in llvm 4.0

[Sanjoy Das via llvm-dev]

Hi Erik,

(I've already replied on IRC, but echoing that here for others)

Hal Finkel wrote:
> [+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}

You need to change !0 to !{!"root"}.  Root nodes must have a single operand.

-- Sanjoy

>> !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
>