[llvm] Add symbol version support to llvm-ifs (PR #163030)

[via llvm-commits]

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@@ -81,12 +91,20 @@ A minimum ELF file that can be used by linker should have following sections pro
 
 * ELF header.
 
+* Program headers. (optional)
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ur4t wrote:

AFAIK, some linkers check program headers too, but they do not complain about missing. So program headers are indeed unnecessary when linking, and the documentation states this optionality.

`llvm-ifs` in this PR emits program headers to better cooperate with other tools. Size cost (around 120 bytes for ELF64) is bearable, there are already lots of padding zeros in generated stubs after all. 

https://github.com/llvm/llvm-project/pull/163030