[PATCH] D71208: CodeGen: Allow annotations on globals in non-zero address space

Mon Dec 9 23:21:33 PST 2019

nhaehnle added a comment.

In D71208#1776202 <https://reviews.llvm.org/D71208#1776202>, @rjmccall wrote:

> The questions I'd like to have answered before I can approve this are:
>
> - whether there are clients of `@llvm.global.annotations` that will have problems with non-0 address spaces and

Yes, that's where this patch is ultimately coming from. I have some work-in-progress code to generate IRBuilder-using C++ code from LLVM IR, which we're currently using internally (with plans to upstream later next year) for an AMDGPU frontend, where non-0 address spaces are used. Using annotations is the least-invasive way I've found to attach required additional data to LLVM IR generated from C...

> - whether this will interfere with someday having an invariant that `addrspacecast` is only used to do legal conversions.

That could potentially be a problem at some point, but this patch isn't making the situation any worse. Without this patch, Clang just unconditionally crashes (hits an assertion) when there's an annotation on a non-0 address space variable. With this patch, in the worst case the crash/assertion comes later...

Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D71208/new/

https://reviews.llvm.org/D71208