[lld] [llvm] [RISCV] Support RISCV Atomics ABI attributes (PR #84597)

[Alex Bradbury via llvm-commits]

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@@ -322,6 +331,49 @@
 #--- atomic_abi_A7.s
 .attribute atomic_abi, 3
 
+
+#      UNKNOWN_UNKNOWN: BuildAttributes {
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asb wrote:

My other two comments were minor nits, this is the one where I'm wondering if there's some missing logic.

For every other case where one of the input files has the atomic_abi attribute and we produce an output, the output file also has the attribute. In this case, although one of the inputs had the attribute we end up dropping it in the output. I think that's probably not desired, but maybe I'm missing a reason to do this?

https://github.com/llvm/llvm-project/pull/84597