[clang] [llvm] [clang] Integrate LLVMABI for function call ABI lowering (PR #194460)

[Nikita Popov via llvm-commits]

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@@ -3588,6 +3588,13 @@ defm modules_reduced_bmi : BoolOption<"f", "modules-reduced-bmi",
 def experimental_modules_reduced_bmi : Flag<["-"], "fexperimental-modules-reduced-bmi">,
   Group<f_Group>, Visibility<[ClangOption, CC1Option]>, Alias<fmodules_reduced_bmi>;
 
+def fexperimental_abi_lowering : Flag<["-"], "fexperimental-abi-lowering">,
+  Group<f_Group>, Visibility<[ClangOption, CC1Option]>,
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nikic wrote:

I think we should make this a CC1Option only, which means you have to use it as `-Xclang -fexperimental-abi-lowering` from the frontend (but without `-Xclang` in tests, because they use clang -cc1).

After all this is a testing option that we don't intend to support long term.

https://github.com/llvm/llvm-project/pull/194460