[lld] [ELF] Support relocatable files using CREL (PR #98115)

[Peter Smith via llvm-commits]

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@@ -470,6 +481,11 @@ void OutputSection::writeTo(uint8_t *buf, parallel::TaskGroup &tg) {
   llvm::TimeTraceScope timeScope("Write sections", name);
   if (type == SHT_NOBITS)
     return;
+  if (type == SHT_CREL && !(flags & SHF_ALLOC)) {
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smithp35 wrote:

Are we expecting to encounter SHF_ALLOC SHT_CREL? If not then we probably ought to add an assertion.

I can see `SHF_ALLOC` `SHT_CREL` could be problematic if the size of the `SHT_CREL` section is sensitive to the contents of the relocations. This might need an encoding per pass of finalizeAddressDependent content.

I can only think of dynamic relocations rela.plt and rela.dyn that are supposed to be `SHF_ALLOC` at the moment.


https://github.com/llvm/llvm-project/pull/98115