[Driver] Don't add -lresolv on FreeBSD

[andrew]

Summary

There is no libresolv on FreeBSD. This fixes the sanitizers on
FreeBSD after https://reviews.llvm.org/D127145

[kda]

clang/lib/Driver/ToolChains/CommonArgs.cpp

840–841

Perhaps expand comment?

[MaskRay]

Perhaps change to isOSLinux() && isGNUEnvironment() now. I suspect other *BSD don't need this, either. musl definitely doesn't need this.

[brad]

I was just looking at the same diff for OpenBSD.

[andrew]

Update the comment

[andrew]

I'll leave it to someone else to get non-FreeBSD working as it's unlikely I'll have time to fix them in the hear future.

[MaskRay]

I pushed 0ba43f4c2b263268f6fbc56bb3f6d43936781957 with an elaborated comment. This patch is not needed now.

clang/lib/Driver/ToolChains/CommonArgs.cpp

 //===--- CommonArgs.cpp - Args handling for multiple toolchains -*- 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
 //
 //===----------------------------------------------------------------------===//
 
void tools::linkSanitizerRuntimeDeps(const ToolChain &TC,
   if (!TC.getTriple().isOSFreeBSD() && !TC.getTriple().isOSNetBSD() &&
       !TC.getTriple().isOSOpenBSD() &&
       TC.getTriple().getOS() != llvm::Triple::RTEMS)
     CmdArgs.push_back("-ldl");
   // Required for backtrace on some OSes
   if (TC.getTriple().isOSFreeBSD() ||
       TC.getTriple().isOSNetBSD() ||
       TC.getTriple().isOSOpenBSD())
     CmdArgs.push_back("-lexecinfo");
-  // There is no libresolv on Android.
-  if (!TC.getTriple().isAndroid())
+  // There is no libresolv on Android or FreeBSD.
+  if (!TC.getTriple().isAndroid() && !TC.getTriple().isOSFreeBSD())
     CmdArgs.push_back("-lresolv");
 }
 
 static void
 collectSanitizerRuntimes(const ToolChain &TC, const ArgList &Args,
                          SmallVectorImpl<StringRef> &SharedRuntimes,
                          SmallVectorImpl<StringRef> &StaticRuntimes,
                          SmallVectorImpl<StringRef> &NonWholeStaticRuntimes,

clang/test/Driver/sanitizer-ld.c

 // CHECK-ASAN-FREEBSD-NOT: "-lc"
 // CHECK-ASAN-FREEBSD-NOT: libclang_rt.asan_cxx
 // CHECK-ASAN-FREEBSD: freebsd{{/|\\+}}libclang_rt.asan-i386.a"
 // CHECK-ASAN-FREEBSD-NOT: libclang_rt.asan_cxx
 // CHECK-ASAN-FREEBSD-NOT: "--dynamic-list"
 // CHECK-ASAN-FREEBSD: "--export-dynamic"
 // CHECK-ASAN-FREEBSD: "-lpthread"
 // CHECK-ASAN-FREEBSD: "-lrt"
-// CHECK-ASAN-FREEBSD: "-lresolv"
 
 // RUN: %clang -### %s 2>&1 \
 // RUN:     --target=i386-unknown-freebsd -fuse-ld=ld -fsanitize=address \
 // RUN:     -resource-dir=%S/Inputs/resource_dir \
 // RUN:     --sysroot=%S/Inputs/basic_freebsd_tree \
 // RUN:   | FileCheck --check-prefix=CHECK-ASAN-FREEBSD-LDL %s
 //
 // CHECK-ASAN-FREEBSD-LDL: "{{(.*[^-.0-9A-Z_a-z])?}}ld{{(.exe)?}}"