[Driver][FreeBSD] -r: imply -nostdlib like GCC

[MaskRay]

Summary

Similar to D116843.

[dim]

LGTM, thanks!

clang/lib/Driver/ToolChains/FreeBSD.cpp

void freebsd::Linker::ConstructJob(Compilation &C, const JobAction &JA,
 
   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_nostartfiles,
+                   options::OPT_r)) {
     const char *crt1 = nullptr;
     if (!Args.hasArg(options::OPT_shared)) {
       if (Args.hasArg(options::OPT_pg))
         crt1 = "gcrt1.o";
       else if (IsPIE)
         crt1 = "Scrt1.o";
       else
         crt1 = "crt1.o";
void freebsd::Linker::ConstructJob(Compilation &C, const JobAction &JA,
 
   bool NeedsSanitizerDeps = addSanitizerRuntimes(ToolChain, Args, CmdArgs);
   bool NeedsXRayDeps = addXRayRuntime(ToolChain, Args, CmdArgs);
   addLinkerCompressDebugSectionsOption(ToolChain, Args, CmdArgs);
   AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs, JA);
 
   unsigned Major = ToolChain.getTriple().getOSMajorVersion();
   bool Profiling = Args.hasArg(options::OPT_pg) && Major != 0 && Major < 14;
-  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
+  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs,
+                   options::OPT_r)) {
     // Use the static OpenMP runtime with -static-openmp
     bool StaticOpenMP = Args.hasArg(options::OPT_static_openmp) &&
                         !Args.hasArg(options::OPT_static);
     addOpenMPRuntime(CmdArgs, ToolChain, Args, StaticOpenMP);
 
     if (D.CCCIsCXX()) {
       if (ToolChain.ShouldLinkCXXStdlib(Args))
         ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
if (Args.hasArg(options::OPT_static)) {
       CmdArgs.push_back("-lgcc_eh_p");
     } else {
       CmdArgs.push_back("--as-needed");
       CmdArgs.push_back("-lgcc_s");
       CmdArgs.push_back("--no-as-needed");
     }
   }
 
-  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles)) {
+  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles,
+                   options::OPT_r)) {
     if (Args.hasArg(options::OPT_shared) || IsPIE)
       CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crtendS.o")));
     else
       CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crtend.o")));
     CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crtn.o")));
   }
 
   ToolChain.addProfileRTLibs(Args, CmdArgs);

clang/test/Driver/freebsd.c

 // Check that the integrated assembler is enabled for SPARC64
 // RUN: %clang -target sparc64-unknown-freebsd -### -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-IAS %s
 // CHECK-IAS-NOT: "-no-integrated-as"
 
 // RUN: %clang -target ppc64-unknown-freebsd13.0 -### -S %s 2>&1 | \
 // RUN: FileCheck -check-prefix=PPC64-MUNWIND %s
 // PPC64-MUNWIND: "-funwind-tables=2"
+
+/// -r suppresses default -l and crt*.o like -nostdlib.
+// RUN: %clang -### %s --target=aarch64-pc-freebsd11 -r \
+// RUN:   --sysroot=%S/Inputs/basic_freebsd64_tree 2>&1 | FileCheck %s --check-prefix=RELOCATABLE
+// RELOCATABLE:     "-r"
+// RELOCATABLE-NOT: "-l
+// RELOCATABLE-NOT: crt{{[^.]+}}.o