[PowerPC] Correctly use ELFv2 ABI on FreeBSD/powerpc64

[pkubaj]

Summary

Currently ELFv2 is mostly set, but some places still default to ELFv1.
While this mostly works, it breaks in particular when lld is used with LTO,
as reported in https://github.com/llvm/llvm-project/issues/46697.

[pkubaj]

Fix indenting according to clang-format suggestions.

[adalava]

Nice catch!
I'm not a LLVM maintainer but from FreeBSD PowerPC side I agree with the changes, only added two suggestions that could improve code readability

clang/lib/Basic/Targets/PPC.h

428

The comparison Triple.getOSMajorVersion() == 0 works, but I think Triple.getOSVersion().empty() would better describe the intent

llvm/lib/Target/PowerPC/PPCTargetMachine.cpp

237

Same here, it could be TT.getOSVersion().empty() instead of TT.getOSMajorVersion() == 0

[pkubaj]

Addres adalava's review.

[brad]

I noticed this review. I have provided a more complete diff for review at D144321.

[dim]

In D144232#4136787, @brad wrote:

I noticed this review. I have provided a more complete diff for review at D144321.

Yeah I think that is probably the better option, hope @pkubaj and @adalava agree with that?

As Brad's version covers both FreeBSD and OpenBSD, and also updates a bunch of unit tests, which this review appears to break (see the Unit Tests https://reviews.llvm.org/harbormaster/unit/214420/).

[adalava]

In D144232#4137367, @dim wrote:

In D144232#4136787, @brad wrote:

I noticed this review. I have provided a more complete diff for review at D144321.

Yeah I think that is probably the better option, hope @pkubaj and @adalava agree with that?

As Brad's version covers both FreeBSD and OpenBSD, and also updates a bunch of unit tests, which this review appears to break (see the Unit Tests https://reviews.llvm.org/harbormaster/unit/214420/).

I agree with D144321, sorry for the late reply. @pkubaj and @brad , thanks for pushing it. I think D144232 can be abandoned, right?

[brad]

In D144232#4155966, @adalava wrote:

I agree with D144321, sorry for the late reply. @pkubaj and @brad , thanks for pushing it. I think D144232 can be abandoned, right?

Correct.

clang/lib/Basic/Targets/PPC.h

 //===--- PPC.h - Declare PPC target feature support -------------*- 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 (Triple.isOSAIX()) {
       // TODO: Set appropriate ABI for AIX platform.
       DataLayout = "E-m:a-i64:64-n32:64";
       LongDoubleWidth = 64;
       LongDoubleAlign = DoubleAlign = 32;
       LongDoubleFormat = &llvm::APFloat::IEEEdouble();
     } else if ((Triple.getArch() == llvm::Triple::ppc64le)) {
       DataLayout = "e-m:e-i64:64-n32:64";
       ABI = "elfv2";
+    } else if (Triple.isOSFreeBSD() && (Triple.getOSVersion().empty() ||
+                                        Triple.getOSMajorVersion() >= 13)) {
+      DataLayout = "E-m:e-i64:64-n32:64";
+      ABI = "elfv2";
     } else {
       DataLayout = "E-m:e-i64:64-n32:64";
       ABI = "elfv1";
     }
 
     if (Triple.isOSFreeBSD() || Triple.isOSOpenBSD() || Triple.isMusl()) {
       LongDoubleWidth = LongDoubleAlign = 64;
       LongDoubleFormat = &llvm::APFloat::IEEEdouble();

llvm/lib/Target/PowerPC/PPCTargetMachine.cpp

 //===-- PPCTargetMachine.cpp - Define TargetMachine for PowerPC -----------===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 //
static PPCTargetMachine::PPCABI computeTargetABI(const Triple &TT,
   if (Options.MCOptions.getABIName().startswith("elfv1"))
     return PPCTargetMachine::PPC_ABI_ELFv1;
   else if (Options.MCOptions.getABIName().startswith("elfv2"))
     return PPCTargetMachine::PPC_ABI_ELFv2;
 
   assert(Options.MCOptions.getABIName().empty() &&
          "Unknown target-abi option!");
 
+  if (TT.isOSFreeBSD() && TT.getArch() == Triple::ppc64 &&
+      (TT.getOSVersion().empty() || TT.getOSMajorVersion() >= 13)) {
+    return PPCTargetMachine::PPC_ABI_ELFv2;
+  }
+
   switch (TT.getArch()) {
   case Triple::ppc64le:
     return PPCTargetMachine::PPC_ABI_ELFv2;
   case Triple::ppc64:
     return PPCTargetMachine::PPC_ABI_ELFv1;
   default:
     return PPCTargetMachine::PPC_ABI_UNKNOWN;
   }