[lld] [lld][MachO] Add --lto-emit-llvm command line option (PR #170355)

[Daniel Rodríguez Troitiño via llvm-commits]

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@@ -188,6 +188,8 @@ def lto_debug_pass_manager: Flag<["--"], "lto-debug-pass-manager">,
     HelpText<"Debug new pass manager">, Group<grp_lld>;
 def lto_newpm_passes: Joined<["--"], "lto-newpm-passes=">,
     HelpText<"Passes to run during LTO">, Group<grp_lld>;
+def lto_emit_llvm: Flag<["--"], "lto-emit-llvm">,
+    HelpText<"Emit LLVM-IR bitcode">;
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drodriguez wrote:

`Group<grp_lld>` since this is a LLD-only option and it is not supported by ld64?

https://github.com/llvm/llvm-project/pull/170355