[Driver] Support macOS

Author: isuruf

clang/lib/Driver/ToolChain.cpp

@@ -1454,7 +1454,9 @@ void ToolChain::AddFortranStdlibLibArgs(const ArgList &Args,
     CmdArgs.push_back("-Bdynamic");
 
   CmdArgs.push_back("-lm");
-  CmdArgs.push_back("-lrt");
+
+  if (!Triple.isOSDarwin())
+    CmdArgs.push_back("-lrt");
 
   // Allways link Fortran executables with Pthreads
   CmdArgs.push_back("-lpthread");

clang/lib/Driver/ToolChains/Darwin.cpp

@@ -759,6 +759,18 @@ void darwin::Linker::ConstructJob(Compilation &C, const JobAction &JA,
   if (getToolChain().ShouldLinkCXXStdlib(Args))
     getToolChain().AddCXXStdlibLibArgs(Args, CmdArgs);
 
+#ifdef ENABLE_CLASSIC_FLANG
+  // Add Fortran runtime libraries
+  if (needFortranLibs(getToolChain().getDriver(), Args)) {
+    getToolChain().AddFortranStdlibLibArgs(Args, CmdArgs);
+  } else {
+    // Claim "no Flang libraries" arguments if any
+    for (auto Arg : Args.filtered(options::OPT_noFlangLibs)) {
+      Arg->claim();
+    }
+  }
+#endif
+
   bool NoStdOrDefaultLibs =
       Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs);
   bool ForceLinkBuiltins = Args.hasArg(options::OPT_fapple_link_rtlib);

clang/lib/Driver/ToolChains/Gnu.cpp

@@ -553,7 +553,7 @@ void tools::gnutools::Linker::ConstructJob(Compilation &C, const JobAction &JA,
   if (needFortranLibs(D, Args)) {
     ToolChain.AddFortranStdlibLibArgs(Args, CmdArgs);
   } else {
-  // Claim "no Flang libraries" arguments if any
+    // Claim "no Flang libraries" arguments if any
     for (auto Arg : Args.filtered(options::OPT_noFlangLibs)) {
       Arg->claim();
     }