[PATCH] D64711: [LTO] Don't override relocation model stored in the module

[Petr Hosek via Phabricator via llvm-commits]

phosek added a comment.

In D64711#1586864 <https://reviews.llvm.org/D64711#1586864>, @pcc wrote:

> I guess I'd be fine with making it so that passing `-relocation-model` explicitly would override lld's decision (see e.g. how we handle function sections/data sections in the gold plugin). Then you can use `-mllvm -relocation-model=pic` for now.


I'd like to better understand the rationale behind the current implementation: eliding relocations feels qualitatively different because that's just an optimization of the linking work, whereas what's being done today in lld is effectively ignoring/overriding the (per-TU) compile-time decision which can lead to surprising results as in our case where we explicitly rely on the distinction between the compilation and linking stages. The LTO code generator should be allowed to relax when instructed to target non-PIC, but that's orthogonal to the linker's role as a linker.

Ultimately what really matters to us is that there's some combination of switches that does what we say, so if there's a strong desire to preserve the current semantics, I'm happy to implement the option to override the relocation model via `-mllvm -relocation-model=pic` as suggested.


Repository:
  rLLD LLVM Linker

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https://reviews.llvm.org/D64711