[lld] [LLD][COFF] Redirect __imp_ Symbols to __imp_aux_ on ARM64EC for x64 sections (PR #108608)

[Jacek Caban via llvm-commits]

cjacek wrote:

I’ve pushed a new version that modifies symbols in `ObjFile` instead, following the same approach as `wrapSymbols()`.

I should also mention an alternative approach that I considered—basing it on the symbol name rather than the resolved symbol type. I tested by defining both `__imp_func` and `__imp_aux_func` in an object file and referencing `__imp_func` from an x64 object file. MSVC linker does not replace the symbol in this case, suggesting that symbol handling should not be based solely on the name. This makes sense, as we need to distinguish between function and data symbols. It also adds another reason to avoid using long import libraries on ARM64EC.

https://github.com/llvm/llvm-project/pull/108608