[Driver] Enable kernel address and memory sanitizers on FreeBSD

[markj]

Summary

Test Plan: using kernel ASAN and MSAN implementations in FreeBSD

[markj]

Enable the memory sanitizer too.

[arichardson]

Does it also work on AArch64?

[markj]

In D98286#2647606, @arichardson wrote:

Does it also work on AArch64?

Not yet, I haven't yet ported the sanitizer runtimes (though it's on my todo list). ASAN requires that we specify the relative offset of the shadow map to the kernel map (see D98285), which will be different on arm64. But, I guess there's no harm in declaring arm64 support in this commit?

[dim]

LGTM, but this would probably need some sort of test, at least that it correctly accepts the flag(s) now?

[markj]

In D98286#2648449, @dim wrote:

LGTM, but this would probably need some sort of test, at least that it correctly accepts the flag(s) now?

Working on it, I see some examples.

[markj]

• Add a couple of regression tests.

clang/lib/Driver/ToolChains/FreeBSD.cpp

 //===--- FreeBSD.cpp - FreeBSD 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 (IsX86_64 || IsMIPS64) {
     Res |= SanitizerKind::Thread;
   }
   if (IsX86 || IsX86_64) {
     Res |= SanitizerKind::Function;
     Res |= SanitizerKind::SafeStack;
     Res |= SanitizerKind::Fuzzer;
     Res |= SanitizerKind::FuzzerNoLink;
   }
-  if (IsX86_64)
+  if (IsX86_64) {
+    Res |= SanitizerKind::KernelAddress;
     Res |= SanitizerKind::Memory;
+  }
   return Res;
 }
 
 void FreeBSD::addClangTargetOptions(const ArgList &DriverArgs,
                                     ArgStringList &CC1Args,
                                     Action::OffloadKind) const {
   if (!DriverArgs.hasFlag(options::OPT_fuse_init_array,
                           options::OPT_fno_use_init_array,
                           getTriple().getOSMajorVersion() >= 12))
     CC1Args.push_back("-fno-use-init-array");
 }