clang driver throws error for -mabi=elfv2 or elfv2

[long5hot]

Summary

After clang release/16.x there is a regression that -mabi=elfv1
or -mabi=elfv2 are being unused and throws warning. But clang-trunk
throws error for -mabi=elfv2 or elfv1. Intent of this patch to accept
elfv1 or elfv2 for -mabi.

PR : https://github.com/llvm/llvm-project/issues/64122
godBolt : https://godbolt.org/z/asbMY1K37

[MaskRay]

After clang release/16.x there is a regression that -mabi=elfv1 or -mabi=elfv2 are being unused and throws warning.

Please just give the full clang command line and add a test case under test/Driver. FWIW: clang --target=powerpc64le-linux-gnu -mabi=elfv1 -mabi=elfv2 -c a.c works for me without any warning.

[long5hot]

failure is only when we do not give full target triple.
for e.x. --target=ppc64 -mabi=elfv2
or even when OS option is unknown e.g. --target=powerpc64-unknown-gnu

[nemanjai]

Ah, ok. This makes sense. When we don't know anything about the ABI, it makes sense to rely on -mabi.

[MaskRay]

clang/test/Driver/ppc-abi.c

18 ↗

(On Diff #544674)

-target has been deprecated since Clang 3.4. Use --target= for new tests:_

[long5hot]

clang/test/Driver/ppc-abi.c

18 ↗

(On Diff #545359)

Did a small testCase change here, because of this #64194 bug ..

clang/lib/Driver/ToolChains/Clang.cpp

 //===-- Clang.cpp - Clang+LLVM ToolChain Implementations --------*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
if (V == "ieeelongdouble") {
       IEEELongDouble = false;
       A->claim();
     } else if (V == "vec-default") {
       VecExtabi = false;
       A->claim();
     } else if (V == "vec-extabi") {
       VecExtabi = true;
       A->claim();
+    } else if (V == "elfv1") {
+      ABIName = "elfv1";
+      A->claim();
+    } else if (V == "elfv2") {
+      ABIName = "elfv2";
+      A->claim();
     } else if (V != "altivec")
       // The ppc64 linux abis are all "altivec" abis by default. Accept and ignore
       // the option if given as we don't have backend support for any targets
       // that don't use the altivec abi.
       ABIName = A->getValue();
   }
   if (IEEELongDouble)
     CmdArgs.push_back("-mabi=ieeelongdouble");