[flang][driver] Add support for `-module-suffix`

[awarzynski]

Summary

This option is required in order to call flang-new from the flang
bash script.

[awarzynski]

Minor tweaks (different suffix in test, updated help text)

[PeteSteinfeld]

All builds, tests, and looks good.

clang/include/clang/Driver/Options.td

def fdebug_measure_parse_tree : Flag<["-"], "fdebug-measure-parse-tree">, Group<Action_Group>,
   HelpText<"Measure the parse tree">;
 def fdebug_pre_fir_tree : Flag<["-"], "fdebug-pre-fir-tree">, Group<Action_Group>,
   HelpText<"Dump the pre-FIR tree">;
 def fdebug_module_writer : Flag<["-"],"fdebug-module-writer">, 
   HelpText<"Enable debug messages while writing module files">;
 def fget_symbols_sources : Flag<["-"], "fget-symbols-sources">, Group<Action_Group>,
   HelpText<"Dump symbols and their source code locations">;
 
+def module_suffix : Separate<["-"], "module-suffix">,  Group<f_Group>, MetaVarName<"<suffix>">,
+  HelpText<"Use <suffix> as the suffix for module files (the default value is `.mod`)">;
+
 }
 
 //===----------------------------------------------------------------------===//
 // CC1 Options
 //===----------------------------------------------------------------------===//
 
 let Flags = [CC1Option, NoDriverOption] in {
 

flang/include/flang/Frontend/CompilerInvocation.h

class CompilerInvocation : public CompilerInvocationBase {
   // Semantics context
   std::unique_ptr<Fortran::semantics::SemanticsContext> semanticsContext_;
 
   /// Semantic options
   // TODO: Merge with or translate to frontendOpts_. We shouldn't need two sets
   // of options.
   std::string moduleDir_ = ".";
 
+  std::string moduleFileSuffix_ = ".mod";
+
   bool debugModuleDir_ = false;
 
   bool warnAsErr_ = false;
 
   // Fortran Dialect options
   Fortran::common::IntrinsicTypeDefaultKinds defaultKinds_;
 
   bool EnableConformanceChecks_ = false;
public:
   }
   const Fortran::semantics::SemanticsContext &semanticsContext() const {
     return *semanticsContext_;
   }
 
   std::string &moduleDir() { return moduleDir_; }
   const std::string &moduleDir() const { return moduleDir_; }
 
+  std::string &moduleFileSuffix() { return moduleFileSuffix_; }
+  const std::string &moduleFileSuffix() const { return moduleFileSuffix_; }
+
   bool &debugModuleDir() { return debugModuleDir_; }
   const bool &debugModuleDir() const { return debugModuleDir_; }
 
   bool &warnAsErr() { return warnAsErr_; }
   const bool &warnAsErr() const { return warnAsErr_; }
 
   bool &enableConformanceChecks() { return EnableConformanceChecks_; }
   const bool &enableConformanceChecks() const {
static bool CreateFromArgs(CompilerInvocation &res,
       clang::DiagnosticsEngine &diags);
 
   // Enables the std=f2018 conformance check
   void set_EnableConformanceChecks() { EnableConformanceChecks_ = true; }
 
   /// Useful setters
   void SetModuleDir(std::string &moduleDir) { moduleDir_ = moduleDir; }
 
+  void SetModuleFileSuffix(const char *moduleFileSuffix) {
+    moduleFileSuffix_ = std::string(moduleFileSuffix);
+  }
+
   void SetDebugModuleDir(bool flag) { debugModuleDir_ = flag; }
 
   void SetWarnAsErr(bool flag) { warnAsErr_ = flag; }
 
   /// Set the Fortran options to predifined defaults. These defaults are
   /// consistend with f18/f18.cpp.
   // TODO: We should map frontendOpts_ to parserOpts_ instead. For that, we
   // need to extend frontendOpts_ first. Next, we need to add the corresponding

flang/lib/Frontend/CompilerInvocation.cpp

static bool parseSemaArgs(CompilerInvocation &res, llvm::opt::ArgList &args,
   if (moduleDirList.size() == 1)
     res.SetModuleDir(moduleDirList[0]);
 
   // -fdebug-module-writer option
   if (args.hasArg(clang::driver::options::OPT_fdebug_module_writer)) {
     res.SetDebugModuleDir(true);
   }
 
+  // -module-suffix
+  if (const auto *moduleSuffix =
+          args.getLastArg(clang::driver::options::OPT_module_suffix)) {
+    res.SetModuleFileSuffix(moduleSuffix->getValue());
+  }
+
   return diags.getNumErrors() == numErrorsBefore;
 }
 
 /// Parses all diagnostics related arguments and populates the variables
 /// options accordingly. Returns false if new errors are generated.
 static bool parseDiagArgs(CompilerInvocation &res, llvm::opt::ArgList &args,
     clang::DiagnosticsEngine &diags) {
   unsigned numErrorsBefore = diags.getNumErrors();
void CompilerInvocation::setSemanticsOpts(
   const auto &fortranOptions = fortranOpts();
 
   semanticsContext_ = std::make_unique<semantics::SemanticsContext>(
       defaultKinds(), fortranOptions.features, allCookedSources);
 
   semanticsContext_->set_moduleDirectory(moduleDir())
       .set_searchDirectories(fortranOptions.searchDirectories)
       .set_warnOnNonstandardUsage(enableConformanceChecks())
-      .set_warningsAreErrors(warnAsErr());
+      .set_warningsAreErrors(warnAsErr())
+      .set_moduleFileSuffix(moduleFileSuffix());
 }

flang/test/Driver/driver-help.f90

 ! HELP-FC1-NEXT: -flarge-sizes          Use INTEGER(KIND=8) for the result type in size-related intrinsics
 ! HELP-FC1-NEXT: -flogical-abbreviations Enable logical abbreviations
 ! HELP-FC1-NEXT: -fopenacc              Enable OpenACC
 ! HELP-FC1-NEXT: -fopenmp               Parse OpenMP pragmas and generate parallel code.
 ! HELP-FC1-NEXT: -fxor-operator         Enable .XOR. as a synonym of .NEQV.
 ! HELP-FC1-NEXT: -help                  Display available options
 ! HELP-FC1-NEXT: -I <dir>               Add directory to the end of the list of include search paths
 ! HELP-FC1-NEXT: -module-dir <dir>      Put MODULE files in <dir>
+! HELP-FC1-NEXT: -module-suffix <suffix> Use <suffix> as the suffix for module files (the default value is `.mod`)
 ! HELP-FC1-NEXT: -nocpp                 Disable predefined and command line preprocessor macros
 ! HELP-FC1-NEXT: -o <file>              Write output to <file>
 ! HELP-FC1-NEXT: -pedantic              Warn on language extensions
 ! HELP-FC1-NEXT: -std=<value>           Language standard to compile for
 ! HELP-FC1-NEXT: -test-io               Run the InputOuputTest action. Use for development and testing only.
 ! HELP-FC1-NEXT: -U <macro>             Undefine macro <macro>
 ! HELP-FC1-NEXT: --version              Print version information
 ! HELP-FC1-NEXT: -W<warning>            Enable the specified warning
 
 !---------------
 ! EXPECTED ERROR
 !---------------
 ! ERROR: error: unknown argument '-helps'; did you mean '-help'

flang/test/Driver/module-suffix.f90

+! Tests `-module-suffix` frontend option
+
+!--------------------------
+! RUN lines
+!--------------------------
+! RUN: rm -rf %t && mkdir -p %t/dir-flang/
+! RUN: cd %t && %flang_fc1 -fsyntax-only -module-suffix .f18.mod -module-dir %t/dir-flang %s
+! RUN: ls %t/dir-flang/testmodule.f18.mod && not ls %t/dir-flang/testmodule.mod
+
+!--------------------------
+! INPUT
+!--------------------------
+module testmodule
+  type::t2
+  end type
+end