[Driver] Support GNU ld on Solaris

[ro]

Summary

This patch is posted just for reference on top of D84029 and D84412.

It's a very first attempt to support GNU ld on Solaris, which is non-trivial given that
both linkers have some options not supported by the other. Currently linker selection
is done at cmake time; it probably needs to be made runtime-selectable.

[MaskRay]

Please find a suitable test file (clang/test/Driver/solaris-*.c) and add some tests there (for example, solaris-ld.c)
The challenge is that CLANG_ENABLE_GLD is not a default configuration, so leaving out tests may be fine.

clang/CMakeLists.txt

281 ↗

(On Diff #283230)

Mention SOLARIS in the variable name? Users on other OSes don't need to read the description of this variable.

It will also make the abbreviation GLD more legitimate. GLD isn't a well-recognized abbreviation for GNU ld.

clang/lib/Driver/ToolChains/Solaris.cpp

354

The hard-coded version doesn't sound great.

[ro]

In D85309#2198505, @MaskRay wrote:

Please find a suitable test file (clang/test/Driver/solaris-*.c) and add some tests there (for example, solaris-ld.c)
The challenge is that CLANG_ENABLE_GLD is not a default configuration, so leaving out tests may be fine.

On top of that, GNU ld may or may not be installed on a particular Solaris systems. So even if the configuration were dynamic instead of hardcoding GNU ld, one would still have to make the test conditional on its presence on the actual system. Same as the somewhat hacky test in D84029.

That said, I don't consider this patch even remotely ready for inclusion. It was primarily meant to show what I'd been using to test that configuration. It has been useful in pinpointing differences between Solaris ld and GNU ld testresults. However, there are quite a number of unexpected asan failures that need to be investigated first.

I'm also not happy with selecting the linker flavour at build time: maybe this can be made dynamic (e.g. parsing ld -V output) to allow for switching between Solaris ld and GNU ld at runtime.

clang/CMakeLists.txt

281 ↗

(On Diff #283230)

As I said, I've only done it this way to allow selecting GNU ld at all. This would become moot if linker flavour detection were
implemented at runtime.

clang/lib/Driver/ToolChains/Solaris.cpp

354

Certainly not: this is a site-local path used to hack around a configuration error in the current bundled GNU ld on Solaris.
That one is being fixed as we speak.

[ro]

This is a major revison of the original WIP patch that should be (close to) ready. Major differences are:

• Linker selection is dynamic now: one can switch between Solaris ld and GNU ld at runtime, with the default selectable with -DCLANG_DEFAULT_LINKER.
• Testcases have been adjusted to test both variants in case there are differences.
• The compiler-rt/cmake/config-ix.cmake and llvm/cmake/modules/AddLLVM.cmake changes to restrict the tests to Solaris ld are necessary because GNU accepts unknown -z options, but warns every time they are used, creating a lot of noise. Since there seems to be no way to check for those warnings in llvm_check_compiler_linker_flag or llvm_check_compiler_linker_flag, I restrict the cmake tests to Solaris ld in the first place.
• The changes to clang/test/Driver/hip-link-bundle-archive.hip and flang/test/Driver/linker-flags.f90 are required to handle the -DCLANG_DEFAULT_LINKER=gld case: when this is passed to cmake, the WebAssembly.cpp getLinkerPath returns /usr/bin/gld instead of the expected link.
• compiler-rt/test/asan/TestCases/global-location-nodebug.cpp needs to enforce the Solaris ld, otherwise the test would XPASS with GNU ld which has the -S semantics expected by the test.

Tested on amd64-pc-solaris2.11 and sparcv9-sun-solaris2.11 with both -DCLANG_DEFAULT_LINKER=gld and the default, and x86_64-pc-linux-gnu. No regressions in either case.

[MaskRay]

clang/lib/Driver/ToolChains/CommonArgs.cpp

306

I suppose that this should be in a Solaris specific file to indicate that it's not for other systems.

GNU ld is almost ubiquitous on Linux and is almost always available at /usr/bin/ld (with very few distributions using others linkers by default or providing an option).

Detecting linker to affect driver decisions is we Linux are very wary of. We are nervous even trying to do some stuff only related to lld.

We likely don't want this function to be in CommonArgs to lure other contributors to use.

[ro]

clang/lib/Driver/ToolChains/CommonArgs.cpp

306

I suppose that this should be in a Solaris specific file to indicate that it's not for other systems.

Indeed. I've moved it to Solaris.{h,cpp} now. In fact, initially i'd tried to assert a Solaris target in isLinkerGnuLd, but that cannot work because in some cases the function is called in common code, even though the result is only used on Solaris.

I briefly thought about generalizing both IsLinkerGnuLd and IsLinkerLLD into a common

enum LinkerFlavour getLinkerFlavor();

but doing this for all possible configs seemed like a can of worms I'd rather not open.

GNU ld is almost ubiquitous on Linux and is almost always available at /usr/bin/ld (with very few distributions using others linkers by default or providing an option).

Detecting linker to affect driver decisions is we Linux are very wary of. We are nervous even trying to do some stuff only related to lld.

I saw: that code is only used on Darwin, it seems, and I'd like to avoid touching that.

We likely don't want this function to be in CommonArgs to lure other contributors to use.

Apart from the move to Solaris.h, I've also moved it into the solaris namespace to make things completely obvious.

[ro]

Move isLinkerGnuLd to Solaris.{h,cpp} and into solaris namespace to make it unambigously clear where to use it.

[MaskRay]

clang/test/Driver/hip-link-bundle-archive.hip

59

Any idea why -fuse-ld= is now needed?

[ro]

clang/test/Driver/hip-link-bundle-archive.hip

59

I've tried to explain it in the change description, but just noticed the filename is wrong:

When LLVM is built with -DCLANG_DEFAULT_LINKER=gld on Solaris, MSVC.cpp visualstudio::Linker::ConstructJob sets Linker to gld. Ultimately, GetProgramPath(Linker) is called, resulting in a search for gld, which exists in /usr/bin/gld on Solaris. With -fuse-ld=, this doesn't happen and the expected link is returned.

[MaskRay]

LGTM.

clang/lib/Driver/ToolChains/Solaris.cpp

55

-fuse-ld=<path> is deprecated by --ld-path=. So just drop this FIXME.

83

clang/lib/Driver/ToolChains/CommonArgs.cpp

 #include "Arch/RISCV.h"
 #include "Arch/Sparc.h"
 #include "Arch/SystemZ.h"
 #include "Arch/VE.h"
 #include "Arch/X86.h"
 #include "HIPAMD.h"
 #include "Hexagon.h"
 #include "MSP430.h"
+#include "Solaris.h"
 #include "clang/Basic/CharInfo.h"
 #include "clang/Basic/LangOptions.h"
 #include "clang/Basic/ObjCRuntime.h"
 #include "clang/Basic/Version.h"
 #include "clang/Config/config.h"
 #include "clang/Driver/Action.h"
 #include "clang/Driver/Compilation.h"
 #include "clang/Driver/Driver.h"
if (A.getOption().matches(options::OPT_Z_reserved_lib_stdcxx))
       TC.AddCXXStdlibLibArgs(Args, CmdArgs);
     else if (A.getOption().matches(options::OPT_Z_reserved_lib_cckext))
       TC.AddCCKextLibArgs(Args, CmdArgs);
     else
       A.renderAsInput(Args, CmdArgs);
   }
 }
 
 void tools::addLinkerCompressDebugSectionsOption(
     const ToolChain &TC, const llvm::opt::ArgList &Args,
     llvm::opt::ArgStringList &CmdArgs) {
   // GNU ld supports --compress-debug-sections=none|zlib|zlib-gnu|zlib-gabi
   // whereas zlib is an alias to zlib-gabi and zlib-gnu is obsoleted. Therefore
   // -gz=none|zlib are translated to --compress-debug-sections=none|zlib. -gz
   // is not translated since ld --compress-debug-sections option requires an
   // argument.
   if (const Arg *A = Args.getLastArg(options::OPT_gz_EQ)) {
static void addSanitizerRuntime(const ToolChain &TC, const ArgList &Args,
   }
 }
 
 // Tries to use a file with the list of dynamic symbols that need to be exported
 // from the runtime library. Returns true if the file was found.
 static bool addSanitizerDynamicList(const ToolChain &TC, const ArgList &Args,
                                     ArgStringList &CmdArgs,
                                     StringRef Sanitizer) {
+  bool LinkerIsGnuLd = solaris::isLinkerGnuLd(TC, Args);
+
   // Solaris ld defaults to --export-dynamic behaviour but doesn't support
   // the option, so don't try to pass it.
-  if (TC.getTriple().getOS() == llvm::Triple::Solaris)
+  if (TC.getTriple().getOS() == llvm::Triple::Solaris && !LinkerIsGnuLd)
     return true;
   SmallString<128> SanRT(TC.getCompilerRT(Args, Sanitizer));
   if (llvm::sys::fs::exists(SanRT + ".syms")) {
     CmdArgs.push_back(Args.MakeArgString("--dynamic-list=" + SanRT + ".syms"));
     return true;
   }
   return false;
 }
 
 void tools::addAsNeededOption(const ToolChain &TC,
                               const llvm::opt::ArgList &Args,
                               llvm::opt::ArgStringList &CmdArgs,
                               bool as_needed) {
   assert(!TC.getTriple().isOSAIX() &&
          "AIX linker does not support any form of --as-needed option yet.");
+  bool LinkerIsGnuLd = solaris::isLinkerGnuLd(TC, Args);
 
   // While the Solaris 11.2 ld added --as-needed/--no-as-needed as aliases
   // for the native forms -z ignore/-z record, they are missing in Illumos,
   // so always use the native form.
-  if (TC.getTriple().isOSSolaris()) {
+  // GNU ld doesn't support -z ignore/-z record, so don't use them even on
+  // Solaris.
+  if (TC.getTriple().isOSSolaris() && !LinkerIsGnuLd) {
     CmdArgs.push_back("-z");
     CmdArgs.push_back(as_needed ? "ignore" : "record");
   } else {
     CmdArgs.push_back(as_needed ? "--as-needed" : "--no-as-needed");
   }
 }
 
 void tools::linkSanitizerRuntimeDeps(const ToolChain &TC,

clang/lib/Driver/ToolChains/Solaris.h

public:
   bool hasIntegratedCPP() const override { return false; }
 
   void ConstructJob(Compilation &C, const JobAction &JA,
                     const InputInfo &Output, const InputInfoList &Inputs,
                     const llvm::opt::ArgList &TCArgs,
                     const char *LinkingOutput) const override;
 };
 
+bool isLinkerGnuLd(const ToolChain &TC, const llvm::opt::ArgList &Args);
+
 class LLVM_LIBRARY_VISIBILITY Linker : public Tool {
 public:
   Linker(const ToolChain &TC) : Tool("solaris::Linker", "linker", TC) {}
 
   bool hasIntegratedCPP() const override { return false; }
   bool isLinkJob() const override { return true; }
+  std::string getLinkerPath(const llvm::opt::ArgList &Args) const;
 
   void ConstructJob(Compilation &C, const JobAction &JA,
                     const InputInfo &Output, const InputInfoList &Inputs,
                     const llvm::opt::ArgList &TCArgs,
                     const char *LinkingOutput) const override;
 };
 } // end namespace solaris
 } // end namespace tools
AddClangSystemIncludeArgs(const llvm::opt::ArgList &DriverArgs,
                             llvm::opt::ArgStringList &CC1Args) const override;
 
   void
   addLibStdCxxIncludePaths(const llvm::opt::ArgList &DriverArgs,
                            llvm::opt::ArgStringList &CC1Args) const override;
 
   SanitizerMask getSupportedSanitizers() const override;
 
-  const char *getDefaultLinker() const override {
-    // clang currently uses Solaris ld-only options.
-    return "/usr/bin/ld";
-  }
+  const char *getDefaultLinker() const override;
 
 protected:
   Tool *buildAssembler() const override;
   Tool *buildLinker() const override;
 };
 
 } // end namespace toolchains
 } // end namespace driver
 } // end namespace clang
 
 #endif // LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_SOLARIS_H

clang/lib/Driver/ToolChains/Solaris.cpp

 #include "clang/Basic/LangStandard.h"
 #include "clang/Config/config.h"
 #include "clang/Driver/Compilation.h"
 #include "clang/Driver/Driver.h"
 #include "clang/Driver/DriverDiagnostic.h"
 #include "clang/Driver/Options.h"
 #include "clang/Driver/SanitizerArgs.h"
 #include "clang/Driver/ToolChain.h"
+#include "llvm/ADT/StringSwitch.h"
 #include "llvm/Option/ArgList.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Path.h"
 
 using namespace clang::driver;
 using namespace clang::driver::tools;
 using namespace clang::driver::toolchains;
 using namespace clang;
void solaris::Assembler::ConstructJob(Compilation &C, const JobAction &JA,
   for (const auto &II : Inputs)
     CmdArgs.push_back(II.getFilename());
 
   const char *Exec = Args.MakeArgString(getToolChain().GetProgramPath("as"));
   C.addCommand(std::make_unique<Command>(JA, *this, ResponseFileSupport::None(),
                                          Exec, CmdArgs, Inputs, Output));
 }
 
+bool solaris::isLinkerGnuLd(const ToolChain &TC, const ArgList &Args) {
+  // Only used if targetting Solaris.
+  const Arg *A = Args.getLastArg(options::OPT_fuse_ld_EQ);
+  StringRef UseLinker = A ? A->getValue() : CLANG_DEFAULT_LINKER;
+  return UseLinker == "bfd" || UseLinker == "gld";
+}
+
 static bool getPIE(const ArgList &Args, const ToolChain &TC) {
   if (Args.hasArg(options::OPT_shared) || Args.hasArg(options::OPT_static) ||
       Args.hasArg(options::OPT_r))
     return false;
 
   Arg *A = Args.getLastArg(options::OPT_pie, options::OPT_no_pie,
                            options::OPT_nopie);
   if (!A)
     return TC.isPIEDefault(Args);
   return A->getOption().matches(options::OPT_pie);
 }
 
+// FIXME: Need to handle CLANG_DEFAULT_LINKER here?
+std::string solaris::Linker::getLinkerPath(const ArgList &Args) const {
+  const ToolChain &ToolChain = getToolChain();
+  if (const Arg *A = Args.getLastArg(options::OPT_fuse_ld_EQ)) {
+    StringRef UseLinker = A->getValue();
+    if (!UseLinker.empty()) {
+      if (llvm::sys::path::is_absolute(UseLinker) &&
+          llvm::sys::fs::can_execute(UseLinker))
+        return std::string(UseLinker);
+
+      // Accept 'bfd' and 'gld' as aliases for the GNU linker.
+      if (UseLinker == "bfd" || UseLinker == "gld")
+        // FIXME: Could also use /usr/bin/gld here.
+        return "/usr/gnu/bin/ld";
+
+      // Accept 'ld' as alias for the default linker
+      if (UseLinker != "ld")
+        ToolChain.getDriver().Diag(diag::err_drv_invalid_linker_name)
+            << A->getAsString(Args);
+    }
+  }
+
+  // getDefaultLinker() always returns an absolute path.
+  return ToolChain.getDefaultLinker();
+}
+
 void solaris::Linker::ConstructJob(Compilation &C, const JobAction &JA,
                                    const InputInfo &Output,
                                    const InputInfoList &Inputs,
                                    const ArgList &Args,
                                    const char *LinkingOutput) const {
   const bool IsPIE = getPIE(Args, getToolChain());
   ArgStringList CmdArgs;
+  bool LinkerIsGnuLd = isLinkerGnuLd(getToolChain(), Args);
 
-  // Demangle C++ names in errors
+  // Demangle C++ names in errors.  GNU ld already defaults to --demangle.
+  if (!LinkerIsGnuLd)
     CmdArgs.push_back("-C");
 
   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_shared)) {
     CmdArgs.push_back("-e");
     CmdArgs.push_back("_start");
   }
 
   if (IsPIE) {
+    if (LinkerIsGnuLd) {
+      CmdArgs.push_back("-pie");
+    } else {
       CmdArgs.push_back("-z");
       CmdArgs.push_back("type=pie");
     }
+  }
 
   if (Args.hasArg(options::OPT_static)) {
     CmdArgs.push_back("-Bstatic");
     CmdArgs.push_back("-dn");
   } else {
     CmdArgs.push_back("-Bdynamic");
     if (Args.hasArg(options::OPT_shared)) {
       CmdArgs.push_back("-shared");
     }
 
     // libpthread has been folded into libc since Solaris 10, no need to do
     // anything for pthreads. Claim argument to avoid warning.
     Args.ClaimAllArgs(options::OPT_pthread);
     Args.ClaimAllArgs(options::OPT_pthreads);
   }
 
+  if (LinkerIsGnuLd) {
+    // Set the correct linker emulation for 32- and 64-bit Solaris.
+    const toolchains::Solaris &ToolChain =
+        static_cast<const toolchains::Solaris &>(getToolChain());
+    const llvm::Triple::ArchType Arch = ToolChain.getArch();
+
+    switch (Arch) {
+    case llvm::Triple::x86:
+      CmdArgs.push_back("-m");
+      CmdArgs.push_back("elf_i386_sol2");
+      break;
+    case llvm::Triple::x86_64:
+      CmdArgs.push_back("-m");
+      CmdArgs.push_back("elf_x86_64_sol2");
+      break;
+    case llvm::Triple::sparc:
+      CmdArgs.push_back("-m");
+      CmdArgs.push_back("elf32_sparc_sol2");
+      break;
+    case llvm::Triple::sparcv9:
+      CmdArgs.push_back("-m");
+      CmdArgs.push_back("elf64_sparc_sol2");
+      break;
+    default:
+      break;
+    }
+
+    if (Args.hasArg(options::OPT_rdynamic))
+      CmdArgs.push_back("-export-dynamic");
+
+    CmdArgs.push_back("--eh-frame-hdr");
+  } else {
+    // -rdynamic is a no-op with Solaris ld.  Claim argument to avoid warning.
+    Args.ClaimAllArgs(options::OPT_rdynamic);
+  }
+
   if (Output.isFilename()) {
     CmdArgs.push_back("-o");
     CmdArgs.push_back(Output.getFilename());
   } else {
     assert(Output.isNothing() && "Invalid output.");
   }
 
   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles,
if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs,
     if (NeedsSanitizerDeps) {
       linkSanitizerRuntimeDeps(getToolChain(), Args, CmdArgs);
 
       // Work around Solaris/amd64 ld bug when calling __tls_get_addr directly.
       // However, ld -z relax=transtls is available since Solaris 11.2, but not
       // in Illumos.
       if (getToolChain().getTriple().getArch() == llvm::Triple::x86_64 &&
           (SA.needsAsanRt() || SA.needsStatsRt() ||
-           (SA.needsUbsanRt() && !SA.requiresMinimalRuntime()))) {
+           (SA.needsUbsanRt() && !SA.requiresMinimalRuntime())) &&
+          !LinkerIsGnuLd) {
         CmdArgs.push_back("-z");
         CmdArgs.push_back("relax=transtls");
       }
     }
     // Avoid AsanInitInternal cycle, Issue #64126.
     if (getToolChain().getTriple().isX86() && SA.needsSharedRt() &&
         SA.needsAsanRt()) {
       CmdArgs.push_back("-z");
else
       CmdArgs.push_back(
           Args.MakeArgString(getToolChain().GetFilePath("crtend.o")));
     CmdArgs.push_back(
         Args.MakeArgString(getToolChain().GetFilePath("crtn.o")));
   }
 
   getToolChain().addProfileRTLibs(Args, CmdArgs);
 
-  const char *Exec = Args.MakeArgString(getToolChain().GetLinkerPath());
+  const char *Exec = Args.MakeArgString(getLinkerPath(Args));
   C.addCommand(std::make_unique<Command>(JA, *this, ResponseFileSupport::None(),
                                          Exec, CmdArgs, Inputs, Output));
 }
 
 static StringRef getSolarisLibSuffix(const llvm::Triple &Triple) {
   switch (Triple.getArch()) {
   case llvm::Triple::x86:
   case llvm::Triple::sparc:
if (IsX86) {
     Res |= SanitizerKind::Address;
     Res |= SanitizerKind::PointerCompare;
     Res |= SanitizerKind::PointerSubtract;
   }
   Res |= SanitizerKind::Vptr;
   return Res;
 }
 
+const char *Solaris::getDefaultLinker() const {
+  // FIXME: Only handle Solaris ld and GNU ld here.
+  return llvm::StringSwitch<const char *>(CLANG_DEFAULT_LINKER)
+      .Cases("bfd", "gld", "/usr/gnu/bin/ld")
+      .Default("/usr/bin/ld");
+}
+
 Tool *Solaris::buildAssembler() const {
   return new tools::solaris::Assembler(*this);
 }
 
 Tool *Solaris::buildLinker() const { return new tools::solaris::Linker(*this); }
 
 void Solaris::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
                                         ArgStringList &CC1Args) const {

clang/test/Driver/hip-link-bundle-archive.hip

 // RUN:   --target=x86_64-unknown-linux-gnu \
 // RUN:   -nogpuinc -nogpulib %s -fgpu-rdc %t/NoneExist.a \
 // RUN:   2>&1 | FileCheck -check-prefixes=NONE %s
 
 // Check unbundling archive for MSVC.
 
 // RUN: llvm-ar cr %t/hipBundled2.lib %t/dummy.bc
 // RUN: %clang -### --offload-arch=gfx906 --offload-arch=gfx1030 \
-// RUN:   --target=x86_64-pc-windows-msvc \
+// RUN:   --target=x86_64-pc-windows-msvc -fuse-ld= \
 // RUN:   -nogpuinc -nogpulib %s -fgpu-rdc -L%t -lhipBundled2 \
 // RUN:   2>&1 | FileCheck -check-prefix=MSVC %s
 
 // RUN: %clang -### --offload-arch=gfx906 --offload-arch=gfx1030 \
-// RUN:   --target=x86_64-pc-windows-msvc \
+// RUN:   --target=x86_64-pc-windows-msvc -fuse-ld= \
 // RUN:   -nogpuinc -nogpulib %s -fgpu-rdc -L%t -l:hipBundled2.lib \
 // RUN:   2>&1 | FileCheck -check-prefix=MSVC %s
 
 // RUN: %clang -### --offload-arch=gfx906 --offload-arch=gfx1030 \
-// RUN:   --target=x86_64-pc-windows-msvc \
+// RUN:   --target=x86_64-pc-windows-msvc -fuse-ld= \
 // RUN:   -nogpuinc -nogpulib %s -fgpu-rdc %t/hipBundled2.lib \
 // RUN:   2>&1 | FileCheck -check-prefix=MSVC %s
 
 // GNU1: "{{.*}}clang-offload-bundler" "-unbundle" "-type=a" "-input={{.*}}[[LIB:libhipBundled\.a]]" "-targets=hip-amdgcn-amd-amdhsa-gfx1030" "-output=[[A1030:.*\.a]]" "-allow-missing-bundles"
 // GNU2: "{{.*}}clang-offload-bundler" "-unbundle" "-type=a" "-input={{.*}}[[LIB:libhipBundled\.a\.5\.2]]" "-targets=hip-amdgcn-amd-amdhsa-gfx1030" "-output=[[A1030:.*\.a]]" "-allow-missing-bundles"
 // GNU: "{{.*}}lld{{.*}}" {{.*}}"-plugin-opt=mcpu=gfx1030" {{.*}} "[[A1030]]"
 // GNU: "{{.*}}clang-offload-bundler" "-unbundle" "-type=a" "-input={{.*}}[[LIB]]" "-targets=hip-amdgcn-amd-amdhsa-gfx906" "-output=[[A906:.*\.a]]" "-allow-missing-bundles"
 // GNU: "{{.*}}lld{{.*}}" {{.*}}"-plugin-opt=mcpu=gfx906" {{.*}} "[[A906]]"

clang/test/Driver/solaris-ld-sanitizer.c

 /// General tests that the ld -z relax=transtls workaround is only applied
 /// on Solaris/amd64. Note that we use sysroot to make these tests
 /// independent of the host system.
 
 /// Check sparc-sun-solaris2.11, 32bit
-// RUN: %clang --target=sparc-sun-solaris2.11 %s -### 2>&1 \
-// RUN:     --gcc-toolchain="" --sysroot=%S/Inputs/solaris_sparc_tree \
-// RUN:   | FileCheck --check-prefix=CHECK-LD-SPARC32 %s
-// CHECK-LD-SPARC32-NOT: "-z" "relax=transtls"
+// RUN: %clang --target=sparc-sun-solaris2.11 %s -### -fuse-ld= \
+// RUN:     --gcc-toolchain="" --sysroot=%S/Inputs/solaris_sparc_tree 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-LD %s
 
 /// Check sparc-sun-solaris2.11, 32bit
-// RUN: %clang -fsanitize=undefined --target=sparc-sun-solaris2.11 %s -### 2>&1 \
-// RUN:     --gcc-toolchain="" --sysroot=%S/Inputs/solaris_sparc_tree \
-// RUN:   | FileCheck --check-prefix=CHECK-LD-SPARC32 %s
-// CHECK-LD-SPARC32-NOT: "-z" "relax=transtls"
+// RUN: %clang -fsanitize=undefined --target=sparc-sun-solaris2.11 %s -### -fuse-ld= \
+// RUN:     --gcc-toolchain="" --sysroot=%S/Inputs/solaris_sparc_tree 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-LD %s
 
 /// Check sparc-sun-solaris2.11, 64bit
-// RUN: %clang -m64 --target=sparc-sun-solaris2.11 %s -### 2>&1 \
-// RUN:     --gcc-toolchain="" --sysroot=%S/Inputs/solaris_sparc_tree \
-// RUN:   | FileCheck --check-prefix=CHECK-LD-SPARC64 %s
-// CHECK-LD-SPARC64-NOT: "-z" "relax=transtls"
+// RUN: %clang -m64 --target=sparc-sun-solaris2.11 %s -### -fuse-ld= \
+// RUN:     --gcc-toolchain="" --sysroot=%S/Inputs/solaris_sparc_tree 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-LD %s
 
 /// Check sparc-sun-solaris2.11, 64bit
-// RUN: %clang -m64 -fsanitize=undefined --target=sparc-sun-solaris2.11 %s -### 2>&1 \
-// RUN:     --gcc-toolchain="" --sysroot=%S/Inputs/solaris_sparc_tree \
-// RUN:   | FileCheck --check-prefix=CHECK-LD-SPARC64 %s
-// CHECK-LD-SPARC64-NOT: "-z" "relax=transtls"
+// RUN: %clang -m64 -fsanitize=undefined --target=sparc-sun-solaris2.11 %s -### -fuse-ld= \
+// RUN:     --gcc-toolchain="" --sysroot=%S/Inputs/solaris_sparc_tree 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-LD %s
 
 /// Check i386-pc-solaris2.11, 32bit
-// RUN: %clang --target=i386-pc-solaris2.11 %s -### 2>&1 \
-// RUN:     --gcc-toolchain="" --sysroot=%S/Inputs/solaris_x86_tree \
-// RUN:   | FileCheck --check-prefix=CHECK-LD-X32 %s
-// CHECK-LD-X32-NOT: "-z" "relax=transtls"
+// RUN: %clang --target=i386-pc-solaris2.11 %s -### -fuse-ld= \
+// RUN:     --gcc-toolchain="" --sysroot=%S/Inputs/solaris_x86_tree 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-LD %s
 
 /// Check i386-pc-solaris2.11, 32bit
-// RUN: %clang -fsanitize=undefined --target=i386-pc-solaris2.11 %s -### 2>&1 \
-// RUN:     --gcc-toolchain="" --sysroot=%S/Inputs/solaris_x86_tree \
-// RUN:   | FileCheck --check-prefix=CHECK-LD-X32 %s
-// CHECK-LD-X32-NOT: "-z" "relax=transtls"
+// RUN: %clang -fsanitize=undefined --target=i386-pc-solaris2.11 %s -### -fuse-ld= \
+// RUN:     --gcc-toolchain="" --sysroot=%S/Inputs/solaris_x86_tree 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-LD %s
 
 /// Check i386-pc-solaris2.11, 64bit
-// RUN: %clang -m64 --target=i386-pc-solaris2.11 %s -### 2>&1 \
-// RUN:     --gcc-toolchain="" --sysroot=%S/Inputs/solaris_x86_tree \
-// RUN:   | FileCheck --check-prefix=CHECK-LD-X64 %s
-// CHECK-LD-X64-NOT: "-z" "relax=transtls"
+// RUN: %clang -m64 --target=i386-pc-solaris2.11 %s -### -fuse-ld= \
+// RUN:     --gcc-toolchain="" --sysroot=%S/Inputs/solaris_x86_tree 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-LD %s
+
+// CHECK-LD-NOT: "-z" "relax=transtls"
 
 /// Check i386-pc-solaris2.11, 64bit
-// RUN: %clang -m64 -fsanitize=undefined --target=i386-pc-solaris2.11 %s -### 2>&1 \
-// RUN:     --gcc-toolchain="" --sysroot=%S/Inputs/solaris_x86_tree \
+// RUN: %clang -m64 -fsanitize=undefined --target=i386-pc-solaris2.11 %s -### -fuse-ld= \
+// RUN:     --gcc-toolchain="" --sysroot=%S/Inputs/solaris_x86_tree 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-LD-X64-UBSAN %s
+// RUN: %clang -m64 -fsanitize=undefined --target=i386-pc-solaris2.11 %s -### -fuse-ld=gld \
+// RUN:     --gcc-toolchain="" --sysroot=%S/Inputs/solaris_x86_tree 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-GLD-X64-UBSAN %s
+
 // CHECK-LD-X64-UBSAN: "-z" "relax=transtls"
+// CHECK-GLD-X64-UBSAN-NOT: "-z" "relax=transtls"
 
 /// General tests that the ld -z now workaround is only applied on
-/// Solaris/i386 with shared libclang_rt.asan.. Note that we use sysroot to
+/// Solaris/i386 with shared libclang_rt.asan. Note that we use sysroot to
 /// make these tests independent of the host system.
 
 /// Check i386-pc-solaris2.11, 32bit, shared libclang_rt.asan
 // RUN: %clang -fsanitize=address -shared-libasan --target=i386-pc-solaris2.11 %s -### 2>&1 \
 // RUN:     --gcc-toolchain="" --sysroot=%S/Inputs/solaris_x86_tree \
 // RUN:   | FileCheck --check-prefix=CHECK-LD-X32-ASAN-SHARED %s
 // CHECK-LD-X32-ASAN-SHARED: "-z" "now"
 
 /// Check i386-pc-solaris2.11, 32bit, static libclang_rt.asan
 // RUN: %clang -fsanitize=address --target=i386-pc-solaris2.11 %s -### 2>&1 \
 // RUN:     --gcc-toolchain="" --sysroot=%S/Inputs/solaris_x86_tree \
 // RUN:   | FileCheck --check-prefix=CHECK-LD-X32-ASAN %s
 // CHECK-LD-X32-ASAN-NOT: "-z" "now"

clang/test/Driver/solaris-ld.c

 // General tests that ld invocations on Solaris targets sane. Note that we use
 // sysroot to make these tests independent of the host system.
 
 // Check sparc-sun-solaris2.11, 32bit
-// RUN: %clang -### %s 2>&1 --target=sparc-sun-solaris2.11 \
+// RUN: %clang -### %s --target=sparc-sun-solaris2.11 -fuse-ld= \
 // RUN:     --gcc-toolchain="" \
-// RUN:     --sysroot=%S/Inputs/solaris_sparc_tree \
-// RUN:   | FileCheck --check-prefix=CHECK-LD-SPARC32 %s
+// RUN:     --sysroot=%S/Inputs/solaris_sparc_tree 2>&1 \
+// RUN:   | FileCheck --check-prefixes=CHECK-LD-SPARC32,CHECK-LD %s
+// RUN: %clang -### %s --target=sparc-sun-solaris2.11 -fuse-ld=gld \
+// RUN:     --gcc-toolchain="" \
+// RUN:     --sysroot=%S/Inputs/solaris_sparc_tree 2>&1 \
+// RUN:   | FileCheck --check-prefixes=CHECK-LD-SPARC32,CHECK-GLD %s
 // CHECK-LD-SPARC32-NOT: warning:
 // CHECK-LD-SPARC32: "-cc1" "-triple" "sparc-sun-solaris2.11"
 // CHECK-LD-SPARC32-SAME: "-isysroot" "[[SYSROOT:[^"]+]]"
 // CHECK-LD-SPARC32: "{{.*}}ld{{(.exe)?}}"
 // CHECK-LD-SPARC32-SAME: "[[SYSROOT]]/usr/gcc/4.8/lib/gcc/sparc-sun-solaris2.11/4.8.2{{/|\\\\}}crt1.o"
 // CHECK-LD-SPARC32-SAME: "[[SYSROOT]]/usr/lib{{/|\\\\}}crti.o"
 // CHECK-LD-SPARC32-SAME: "[[SYSROOT]]/usr/gcc/4.8/lib/gcc/sparc-sun-solaris2.11/4.8.2{{/|\\\\}}crtbegin.o"
 // CHECK-LD-SPARC32-SAME: "-L[[SYSROOT]]/usr/gcc/4.8/lib/gcc/sparc-sun-solaris2.11/4.8.2"
 // CHECK-LD-SPARC32-SAME: "-L[[SYSROOT]]/usr/gcc/4.8/lib/gcc/sparc-sun-solaris2.11/4.8.2/../../.."
 // CHECK-LD-SPARC32-SAME: "-L[[SYSROOT]]/usr/lib"
-// CHECK-LD-SPARC32-SAME: "-z" "ignore" "-latomic" "-z" "record"
+// CHECK-LD: "-z" "ignore" "-latomic" "-z" "record"
+// CHECK-GLD: "--as-needed" "-latomic" "--no-as-needed"
 // CHECK-LD-SPARC32-SAME: "-lgcc_s"
 // CHECK-LD-SPARC32-SAME: "-lc"
 // CHECK-LD-SPARC32-SAME: "-lgcc"
 // CHECK-LD-SPARC32-SAME: "-lm"
 // CHECK-LD-SPARC32-SAME: "[[SYSROOT]]/usr/gcc/4.8/lib/gcc/sparc-sun-solaris2.11/4.8.2{{/|\\\\}}crtend.o"
 // CHECK-LD-SPARC32-SAME: "[[SYSROOT]]/usr/lib{{/|\\\\}}crtn.o"
 
 // Check sparc-sun-solaris2.11, 64bit

 // RUN:   | FileCheck --check-prefix=CHECK-SPARC32-SHARED %s
 // CHECK-SPARC32-SHARED: "{{.*}}ld{{(.exe)?}}"
 // CHECK-SPARC32-SHARED-SAME: "-lgcc_s"
 // CHECK-SPARC32-SHARED-SAME: "-lc"
 // CHECK-SPARC32-SHARED-NOT: "-lgcc"
 // CHECK-SPARC32-SHARED-NOT: "-lm"
 
 // Check the right ld flags are present with -pie.
-// RUN: %clang --target=sparc-sun-solaris2.11 -### %s -pie \
+// RUN: %clang --target=sparc-sun-solaris2.11 -### %s -pie -fuse-ld= \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/solaris_sparc_tree 2>&1 \
-// RUN:   | FileCheck --check-prefix=CHECK-PIE %s
-// RUN: %clang --target=sparc-sun-solaris2.11 -### %s -nopie \
+// RUN:   | FileCheck --check-prefix=CHECK-PIE-LD %s
+// RUN: %clang --target=sparc-sun-solaris2.11 -### %s -pie -fuse-ld=gld \
+// RUN:     --gcc-toolchain="" \
+// RUN:     --sysroot=%S/Inputs/solaris_sparc_tree 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-PIE-GLD %s
+// RUN: %clang --target=sparc-sun-solaris2.11 -### %s -nopie -fuse-ld= \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/solaris_sparc_tree 2>&1 \
-// RUN:   | FileCheck --check-prefix=CHECK-NOPIE %s
+// RUN:   | FileCheck --check-prefix=CHECK-NOPIE-LD %s
+// RUN: %clang --target=sparc-sun-solaris2.11 -### %s -nopie -fuse-ld=gld \
+// RUN:     --gcc-toolchain="" \
+// RUN:     --sysroot=%S/Inputs/solaris_sparc_tree 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-NOPIE-GLD %s
 
 // Check that -shared/-r/-static disable PIE.
-// RUN: %clang --target=sparc-sun-solaris2.11 -### %s -shared -pie \
+// RUN: %clang --target=sparc-sun-solaris2.11 -### %s -shared -pie -fuse-ld= \
+// RUN:     --gcc-toolchain="" \
+// RUN:     --sysroot=%S/Inputs/solaris_sparc_tree 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-NOPIE-LD %s
+// RUN: %clang --target=sparc-sun-solaris2.11 -### %s -shared -pie -fuse-ld=gld \
+// RUN:     --gcc-toolchain="" \
+// RUN:     --sysroot=%S/Inputs/solaris_sparc_tree 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-NOPIE-GLD %s
+// RUN: %clang --target=sparc-sun-solaris2.11 -### %s -r -pie -fuse-ld= \
+// RUN:     --gcc-toolchain="" \
+// RUN:     --sysroot=%S/Inputs/solaris_sparc_tree 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-NOPIE-LD %s
+// RUN: %clang --target=sparc-sun-solaris2.11 -### %s -r -pie -fuse-ld=gld \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/solaris_sparc_tree 2>&1 \
-// RUN:   | FileCheck --check-prefix=CHECK-NOPIE %s
-// RUN: %clang --target=sparc-sun-solaris2.11 -### %s -r -pie \
+// RUN:   | FileCheck --check-prefix=CHECK-NOPIE-GLD %s
+// RUN: %clang --target=sparc-sun-solaris2.11 -### %s -static -pie -fuse-ld= \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/solaris_sparc_tree 2>&1 \
-// RUN:   | FileCheck --check-prefix=CHECK-NOPIE %s
-// RUN: %clang --target=sparc-sun-solaris2.11 -### %s -static -pie \
+// RUN:   | FileCheck --check-prefix=CHECK-NOPIE-LD %s
+// RUN: %clang --target=sparc-sun-solaris2.11 -### %s -static -pie -fuse-ld=gld \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/solaris_sparc_tree 2>&1 \
-// RUN:   | FileCheck --check-prefix=CHECK-NOPIE %s
+// RUN:   | FileCheck --check-prefix=CHECK-NOPIE-GLD %s
 
-// CHECK-PIE: "-z" "type=pie"
-// CHECK-NOPIE-NOT: "-z" "type=pie"
+// CHECK-PIE-LD: "-z" "type=pie"
+// CHECK-PIE-GLD: "-pie"
+// CHECK-NOPIE-LD-NOT: "-z" "type=pie"
+// CHECK-NOPIE-GLD-NOT: "-pie"
 
 // -r suppresses default -l and crt*.o, values-*.o like -nostdlib.
 // RUN: %clang -### %s --target=sparc-sun-solaris2.11 -r 2>&1 \
 // RUN:   | FileCheck %s --check-prefix=CHECK-RELOCATABLE
 // CHECK-RELOCATABLE:     "-L
 // CHECK-RELOCATABLE:     "-r"
 // CHECK-RELOCATABLE-NOT: "-l
 // CHECK-RELOCATABLE-NOT: /crt{{[^.]+}}.o

compiler-rt/cmake/config-ix.cmake

 include(CMakePushCheckState)
+include(AddLLVM)
 include(LLVMCheckCompilerLinkerFlag)
 include(CheckCCompilerFlag)
 include(CheckCXXCompilerFlag)
 include(CheckIncludeFiles)
 include(CheckLibraryExists)
 include(LLVMCheckCompilerLinkerFlag)
 include(CheckSymbolExists)
 include(TestBigEndian)

 endif()
 check_library_exists(c++ __cxa_throw "" COMPILER_RT_HAS_LIBCXX)
 check_library_exists(stdc++ __cxa_throw "" COMPILER_RT_HAS_LIBSTDCXX)
 
 # Linker flags.
 llvm_check_compiler_linker_flag(C "-Wl,-z,text" COMPILER_RT_HAS_Z_TEXT)
 llvm_check_compiler_linker_flag(C "-fuse-ld=lld" COMPILER_RT_HAS_FUSE_LD_LLD_FLAG)
 
-if(${CMAKE_SYSTEM_NAME} MATCHES "SunOS")
+if(${CMAKE_SYSTEM_NAME} MATCHES "SunOS" AND LLVM_LINKER_IS_SOLARISLD)
   set(VERS_COMPAT_OPTION "-Wl,-z,gnu-version-script-compat")
   llvm_check_compiler_linker_flag(C "${VERS_COMPAT_OPTION}" COMPILER_RT_HAS_GNU_VERSION_SCRIPT_COMPAT)
 endif()
 
 set(DUMMY_VERS ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/dummy.vers)
 file(WRITE ${DUMMY_VERS} "{};")
 set(VERS_OPTION "-Wl,--version-script,${DUMMY_VERS}")
 if(COMPILER_RT_HAS_GNU_VERSION_SCRIPT_COMPAT)

compiler-rt/test/asan/TestCases/global-location-nodebug.cpp

 /// Same as global-location.cpp, but without debuginfo. In a separate file to
 /// allow this test to also run on Windows (which can't be done for the
 /// debuginfo variant).
 
-// RUN: %clangxx_asan -O2 %S/global-location.cpp -o %t %if target={{.*-windows-msvc.*}} %{ -Wl,/DEBUG:NONE %} %else %{ -Wl,-S %}
+// RUN: %clangxx_asan -O2 %S/global-location.cpp -o %t %if target={{.*-windows-msvc.*}} %{ -Wl,/DEBUG:NONE %} %else %{ -Wl,-S %} %if target={{.*-solaris.*}} %{ -fuse-ld= %}
 // RUN: not %run %t g 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=GLOB-NO-G
 // RUN: not %run %t c 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=CLASS_STATIC-NO-G
 // RUN: not %run %t f 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=FUNC_STATIC-NO-G
 // RUN: not %run %t l 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=LITERAL-NO-G
 
-/// Solaris ld -S has different semantics.
+/// Solaris ld -S has different semantics, so enforce -fuse-ld= for
+/// configurations that default to GNU ld.
 // XFAIL: target={{.*solaris.*}}
 
 // CHECK: AddressSanitizer: global-buffer-overflow
 // CLASS_STATIC-NO-G: 0x{{.*}} is located 4 bytes after global variable '{{.*}}C::array{{.*}}' defined in '{{.*}}global-location.cpp' {{.*}} of size 40
 // GLOB-NO-G: 0x{{.*}} is located 4 bytes after global variable '{{.*}}global{{.*}}' defined in '{{.*}}global-location.cpp' {{.*}} of size 40
 // FUNC_STATIC-NO-G: 0x{{.*}} is located 4 bytes after global variable '{{.*}}main{{.*}}::array{{.*}}' defined in '{{.*}}global-location.cpp' {{.*}} of size 40
 // LITERAL-NO-G: 0x{{.*}} is located 0 bytes after global variable {{.*}} defined in '{{.*}}global-location.cpp' {{.*}} of size 11
 // CHECK: SUMMARY: AddressSanitizer: global-buffer-overflow

flang/test/Driver/linker-flags.f90

 ! Verify that the Fortran runtime libraries are present in the linker
 ! invocation. These libraries are added on top of other standard runtime
 ! libraries that the Clang driver will include.
 
 ! RUN: %flang -### -target ppc64le-linux-gnu %S/Inputs/hello.f90 2>&1 | FileCheck %s --check-prefixes=CHECK,GNU
 ! RUN: %flang -### -target aarch64-apple-darwin %S/Inputs/hello.f90 2>&1 | FileCheck %s --check-prefixes=CHECK,DARWIN
 ! RUN: %flang -### -target x86_64-windows-gnu %S/Inputs/hello.f90 2>&1 | FileCheck %s --check-prefixes=CHECK,MINGW
 
 ! NOTE: Clang's driver library, clangDriver, usually adds 'libcmt' and
 !       'oldnames' on Windows, but they are not needed when compiling
 !       Fortran code and they might bring in additional dependencies.
 !       Make sure they're not added.
-! RUN: %flang -### -target aarch64-windows-msvc %S/Inputs/hello.f90 2>&1 | FileCheck %s --check-prefixes=CHECK,MSVC --implicit-check-not libcmt --implicit-check-not oldnames
+! RUN: %flang -### -target aarch64-windows-msvc -fuse-ld= %S/Inputs/hello.f90 2>&1 | FileCheck %s --check-prefixes=CHECK,MSVC --implicit-check-not libcmt --implicit-check-not oldnames
 
 ! Compiler invocation to generate the object file
 ! CHECK-LABEL: {{.*}} "-emit-obj"
 ! CHECK-SAME:  "-o" "[[object_file:.*\.o]]" {{.*}}Inputs/hello.f90
 
 ! Linker invocation to generate the executable
 ! NOTE: Since we are cross-compiling, the host toolchain executables may
 !       run on any other platform, such as Windows that use a .exe

llvm/cmake/modules/AddLLVM.cmake

function(add_link_opts target_name)
   # Don't use linker optimizations in debug builds since it slows down the
   # linker in a context where the optimizations are not important.
   if (NOT uppercase_CMAKE_BUILD_TYPE STREQUAL "DEBUG")
     if(NOT LLVM_NO_DEAD_STRIP)
       if(${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
         # ld64's implementation of -dead_strip breaks tools that use plugins.
         set_property(TARGET ${target_name} APPEND_STRING PROPERTY
                      LINK_FLAGS " -Wl,-dead_strip")
-      elseif(${CMAKE_SYSTEM_NAME} MATCHES "SunOS")
+      elseif(${CMAKE_SYSTEM_NAME} MATCHES "SunOS" AND LLVM_LINKER_IS_SOLARISLD)
         # Support for ld -z discard-unused=sections was only added in
-        # Solaris 11.4.
+        # Solaris 11.4.  GNU ld ignores it, but warns every time.
         include(LLVMCheckLinkerFlag)
         llvm_check_linker_flag(CXX "-Wl,-z,discard-unused=sections" LINKER_SUPPORTS_Z_DISCARD_UNUSED)
         if (LINKER_SUPPORTS_Z_DISCARD_UNUSED)
           set_property(TARGET ${target_name} APPEND_STRING PROPERTY
                        LINK_FLAGS " -Wl,-z,discard-unused=sections")
         endif()
       elseif(NOT MSVC AND NOT CMAKE_SYSTEM_NAME MATCHES "AIX|OS390")
         # TODO Revisit this later on z/OS.
elseif (LLVM_EXPORT_SYMBOLS_FOR_PLUGINS)
     if(CYGWIN OR MINGW)
       set_target_properties(${target} PROPERTIES IMPORT_SUFFIX ".exe.a")
     endif()
   elseif(NOT (WIN32 OR CYGWIN))
     # On Windows auto-exporting everything doesn't work because of the limit on
     # the size of the exported symbol table, but on other platforms we can do
     # it without any trouble.
     set_target_properties(${target} PROPERTIES ENABLE_EXPORTS 1)
-    if (APPLE)
+    # CMake doesn't set CMAKE_EXE_EXPORTS_${lang}_FLAG on Solaris, so
+    # ENABLE_EXPORTS has no effect.  While Solaris ld defaults to -rdynamic
+    # behaviour, GNU ld needs it.
+    if (APPLE OR ${CMAKE_SYSTEM_NAME} STREQUAL "SunOS")
       set_property(TARGET ${target} APPEND_STRING PROPERTY
         LINK_FLAGS " -rdynamic")
     endif()
   endif()
 endfunction()
 
 # Export symbols if LLVM plugins are enabled.
 function(export_executable_symbols_for_plugins target)