[PATCH] D45181: [RISCV] Add diff relocation support for RISC-V

[Hsiangkai Wang via Phabricator via llvm-commits]

HsiangKai added a comment.

In D45181#1470189 <https://reviews.llvm.org/D45181#1470189>, @jrtc27 wrote:

> The problem is that `Length` is the length of the CIE, i.e. the data structure itself; this means it isn't subject to relaxations and so the difference expression can be folded. I don't see much merit in teaching all the tools out there to check relocations for `Length` when we can instead just emit the "right" thing. I think the fix is to make sure we only return true from `requiresDiffExpressionRelocations` if a target is in a code section? `MCSection::UseCodeAlign` will tell you this (or you can use `MCSectionELF::getFlags() & ELF::SHF_EXECINSTR` to be less general), though perhaps it should be renamed to `isCodeSection` to match `isVirtualSection`.


Use SHF_EXECINSTR flag may be not enough. Several debug information sections also need relocations. For example, although it has no need to generate relocations for `Length` in FDE, it needs relocations for `Address Range` in FDE. These two attributes are located in the same section and the section has no SHF_EXECINSTR flag.


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  rL LLVM

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  https://reviews.llvm.org/D45181/new/

https://reviews.llvm.org/D45181