Linking with MSVC toolchain

lib/Driver/ToolChains/CommonArgs.cpp

@@ -67,7 +67,7 @@ bool tools::needFortranLibs(const Driver &D, const ArgList &Args) {
 }
 
 /// \brief Determine if Fortran "main" object is needed
-static bool needFortranMain(const Driver &D, const ArgList &Args) {
+bool tools::needFortranMain(const Driver &D, const ArgList &Args) {
   return (needFortranLibs(D, Args)
        && (!Args.hasArg(options::OPT_Mnomain) ||
            !Args.hasArg(options::OPT_no_fortran_main)));

lib/Driver/ToolChains/CommonArgs.h

@@ -22,6 +22,8 @@ namespace tools {
 
 bool needFortranLibs(const Driver &D, const llvm::opt::ArgList &Args);
 
+bool needFortranMain(const Driver &D, const llvm::opt::ArgList &Args);
+
 void addPathIfExists(const Driver &D, const Twine &Path,
                      ToolChain::path_list &Paths);
 

lib/Driver/ToolChains/Flang.cpp

@@ -1050,6 +1050,14 @@ if(Args.getAllArgValues(options::OPT_fopenmp_targets_EQ).size() > 0) {
     LowerCmdArgs.push_back(Args.MakeArgString(OutFile));
   }
 
+  bool IsWindowsMSVC = getToolChain().getTriple().isWindowsMSVCEnvironment();
+  if (IsWindowsMSVC && !Args.hasArg(options::OPT_noFlangLibs)) {
+    getToolChain().AddFortranStdlibLibArgs(Args, LowerCmdArgs);
+    for (auto Arg : Args.filtered(options::OPT_noFlangLibs)) {
+      Arg->claim();
+    }
+  }
+
   C.addCommand(llvm::make_unique<Command>(JA, *this, LowerExec, LowerCmdArgs, Inputs));
 }
 

lib/Driver/ToolChains/MSVC.cpp

@@ -326,7 +326,7 @@ void visualstudio::Linker::ConstructJob(Compilation &C, const JobAction &JA,
         Args.MakeArgString(std::string("-out:") + Output.getFilename()));
 
   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles) &&
-      !C.getDriver().IsCLMode())
+      !C.getDriver().IsCLMode() && !C.getDriver().IsFortranMode())
     CmdArgs.push_back("-defaultlib:libcmt");
 
   if (!llvm::sys::Process::GetEnv("LIB")) {
@@ -426,6 +426,11 @@ void visualstudio::Linker::ConstructJob(Compilation &C, const JobAction &JA,
     }
   }
 
+  if (C.getDriver().IsFortranMode()) {
+    CmdArgs.push_back(Args.MakeArgString(std::string("-libpath:") +
+                                         TC.getDriver().Dir + "/../lib"));
+  }
+
   // Add compiler-rt lib in case if it was explicitly
   // specified as an argument for --rtlib option.
   if (!Args.hasArg(options::OPT_nostdlib)) {
@@ -736,6 +741,85 @@ void MSVCToolChain::AddCudaIncludeArgs(const ArgList &DriverArgs,
   CudaInstallation.AddCudaIncludeArgs(DriverArgs, CC1Args);
 }
 
+
+void MSVCToolChain::AddFortranStdlibLibArgs(const ArgList &Args,
+                                    ArgStringList &CmdArgs) const {
+ bool staticFlangLibs = false;
+ bool useOpenMP = false;
+
+  if (Args.hasArg(options::OPT_staticFlangLibs)) {
+    for (auto *A: Args.filtered(options::OPT_staticFlangLibs)) {
+      A->claim();
+      staticFlangLibs = true;
+    }
+  }
+
+  Arg *A = Args.getLastArg(options::OPT_mp, options::OPT_nomp,
+                           options::OPT_fopenmp, options::OPT_fno_openmp);
+  if (A &&
+      (A->getOption().matches(options::OPT_mp) ||
+       A->getOption().matches(options::OPT_fopenmp))) {
+      useOpenMP = true;
+  }
+
+  if (needFortranMain(getDriver(), Args)) {
+    // flangmain is always static
+    CmdArgs.push_back("-linker");
+    CmdArgs.push_back("/subsystem:console");
+    CmdArgs.push_back("-linker");
+    CmdArgs.push_back("/defaultlib:flangmain.lib");
+  }
+
+  if (staticFlangLibs) {
+    CmdArgs.push_back("-linker");
+    CmdArgs.push_back("/defaultlib:libflang.lib");
+    CmdArgs.push_back("-linker");
+    CmdArgs.push_back("/defaultlib:libflangrti.lib");
+    CmdArgs.push_back("-linker");
+    CmdArgs.push_back("/defaultlib:libpgmath.lib");
+  } else {
+    CmdArgs.push_back("-linker");
+    CmdArgs.push_back("/defaultlib:flang.lib");
+    CmdArgs.push_back("-linker");
+    CmdArgs.push_back("/defaultlib:flangrti.lib");
+    CmdArgs.push_back("-linker");
+    CmdArgs.push_back("/defaultlib:pgmath.lib");
+  }
+  if (useOpenMP) {
+    CmdArgs.push_back("-linker");
+    CmdArgs.push_back("/nodefaultlib:vcomp.lib");
+    CmdArgs.push_back("-linker");
+    CmdArgs.push_back("/nodefaultlib:vcompd.lib");
+    CmdArgs.push_back("-linker");
+    CmdArgs.push_back("/defaultlib:libomp.lib");
+  }
+  else {
+    if (staticFlangLibs) {
+      CmdArgs.push_back("-linker");
+      CmdArgs.push_back("/defaultlib:libompstub.lib");
+    } else {
+      CmdArgs.push_back("-linker");
+      CmdArgs.push_back("/defaultlib:ompstub.lib");
+    }
+  }
+
+  // Allways link Fortran executables with Pthreads
+  // CmdArgs.push_back("-lpthread");
+
+  // These options are added clang-cl in Clang.cpp for C/C++
+  // In clang-cl.exe -MD and -MT control these options, but in
+  // flang.exe like clang.exe these are different options for
+  // dependency tracking. Let's assume that if somebody needs
+  // static flang libs, they need static runtime libs as well.
+  if (staticFlangLibs) {
+    CmdArgs.push_back("-linker");
+    CmdArgs.push_back("/defaultlib:libcmt.lib");
+  } else {
+    CmdArgs.push_back("-linker");
+    CmdArgs.push_back("/defaultlib:msvcrt.lib");
+  }
+}
+
 void MSVCToolChain::printVerboseInfo(raw_ostream &OS) const {
   CudaInstallation.print(OS);
 }

lib/Driver/ToolChains/MSVC.h

@@ -109,6 +109,9 @@ class LLVM_LIBRARY_VISIBILITY MSVCToolChain : public ToolChain {
   void AddCudaIncludeArgs(const llvm::opt::ArgList &DriverArgs,
                           llvm::opt::ArgStringList &CC1Args) const override;
 
+  void AddFortranStdlibLibArgs(const llvm::opt::ArgList &Args,
+                               llvm::opt::ArgStringList &CmdArgs) const override;
+
   bool getWindowsSDKLibraryPath(std::string &path) const;
   /// \brief Check if Universal CRT should be used if available
   bool getUniversalCRTLibraryPath(std::string &path) const;