Enable -E, -P flags (Fortran preprocessing)

Author: vjayathirtha-nv

lib/Driver/Driver.cpp

@@ -218,22 +218,31 @@ phases::ID Driver::getFinalPhase(const DerivedArgList &DAL,
 
   // -{E,EP,P,M,MM} only run the preprocessor.
   if (CCCIsCPP() || (PhaseArg = DAL.getLastArg(options::OPT_E)) ||
+      (PhaseArg = DAL.getLastArg(options::OPT_fsyntax_only)) ||
       (PhaseArg = DAL.getLastArg(options::OPT__SLASH_EP)) ||
       (PhaseArg = DAL.getLastArg(options::OPT_M, options::OPT_MM)) ||
       (PhaseArg = DAL.getLastArg(options::OPT__SLASH_P))) {
-    FinalPhase = phases::Preprocess;
 
-    // -fsyntax-only stops Fortran compilation after FortranFrontend
-  } else if (IsFortranMode() && (PhaseArg = DAL.getLastArg(options::OPT_fsyntax_only))) {
-    FinalPhase = phases::FortranFrontend;
+    // -fsyntax-only or -E stops Fortran compilation after FortranFrontend
+    if (IsFortranMode() && (DAL.getLastArg(options::OPT_E) ||
+      DAL.getLastArg(options::OPT_fsyntax_only))) {
+      FinalPhase = phases::FortranFrontend;
+
+      // if not Fortran, fsyntax_only implies 'Compile' is the FinalPhase
+    } else if (DAL.getLastArg(options::OPT_fsyntax_only)) {
+      FinalPhase = phases::Compile;
+
+      // everything else has 'Preprocess' as its FinalPhase
+    } else {
+      FinalPhase = phases::Preprocess;
+    }
 
     // --precompile only runs up to precompilation.
   } else if ((PhaseArg = DAL.getLastArg(options::OPT__precompile))) {
     FinalPhase = phases::Precompile;
 
-    // -{fsyntax-only,-analyze,emit-ast} only run up to the compiler.
-  } else if ((PhaseArg = DAL.getLastArg(options::OPT_fsyntax_only)) ||
-             (PhaseArg = DAL.getLastArg(options::OPT_module_file_info)) ||
+    // -{analyze,emit-ast} only run up to the compiler.
+  } else if ((PhaseArg = DAL.getLastArg(options::OPT_module_file_info)) ||
              (PhaseArg = DAL.getLastArg(options::OPT_verify_pch)) ||
              (PhaseArg = DAL.getLastArg(options::OPT_rewrite_objc)) ||
              (PhaseArg = DAL.getLastArg(options::OPT_rewrite_legacy_objc)) ||

lib/Driver/ToolChains/Flang.cpp

@@ -613,11 +613,25 @@ void FlangFrontend::ConstructJob(Compilation &C, const JobAction &JA,
   // Enable preprocessor
   if (Args.hasArg(options::OPT_Mpreprocess) ||
       Args.hasArg(options::OPT_cpp) ||
+      Args.hasArg(options::OPT_E) ||
       types::getPreprocessedType(InputType) != types::TY_INVALID) {
     UpperCmdArgs.push_back("-preprocess");
-    for (auto Arg : Args.filtered(options::OPT_Mpreprocess, options::OPT_cpp)) {
+    for (auto Arg : Args.filtered(options::OPT_Mpreprocess, options::OPT_cpp, options::OPT_E)) {
       Arg->claim();
     }
+
+    // When -E option is provided, run only the fortran preprocessor.
+    // Only in -E mode, consume -P if it exists
+    if (Args.hasArg(options::OPT_E)) {
+      UpperCmdArgs.push_back("-es");
+      // Line marker mode is disabled
+      if (Args.hasArg(options::OPT_P)) {
+        Args.ClaimAllArgs(options::OPT_P);
+      } else {
+        // -pp enables line marker mode in fortran preprocessor
+        UpperCmdArgs.push_back("-pp");
+      }
+    }
   }
 
   // Enable standards checking
@@ -760,8 +774,9 @@ void FlangFrontend::ConstructJob(Compilation &C, const JobAction &JA,
 
   C.addCommand(llvm::make_unique<Command>(JA, *this, UpperExec, UpperCmdArgs, Inputs));
 
-  // For -fsyntax-only that is it
-  if (Args.hasArg(options::OPT_fsyntax_only)) return;
+  // For -fsyntax-only or -E that is it
+  if (Args.hasArg(options::OPT_fsyntax_only) ||
+      Args.hasArg(options::OPT_E)) return;
 
   /***** Lower part of Fortran frontend *****/