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

[Andy Kaylor via cfe-commits]

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@@ -876,6 +915,27 @@ const CGFunctionInfo &CodeGenTypes::arrangeLLVMFunctionInfo(
     computeSPIRKernelABIInfo(CGM, *FI);
   } else if (info.getCC() == CC_Swift || info.getCC() == CC_SwiftAsync) {
     swiftcall::computeABIInfo(CGM, *FI);
+  } else if (CGM.shouldUseLLVMABILowering()) {
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andykaylor wrote:

Maybe move the code below into a function like `CodeGenModule::computeABIInfoUsingLib`?

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