[flang][driver] Move isFixedFormSuffix and isFreeFormSuffix to flangFrontend

isFixedFormSuffix and isFreeFormSuffix should be defined in
flangFrontend rather than flangFrontendTool library. That's for 2
reasons:
  * these methods are used in flangFrontend rather than flangFrontendTool
  * flangFrontendTool depends on flangFrontend

As mentioned in the post-commit review for D94228, without this change
shared library builds fail.

Differential Revision: https://reviews.llvm.org/D94968

flang/include/flang/Frontend/FrontendOptions.h

@@ -35,6 +35,14 @@ enum ActionKind {
   /// EmitCodeGenOnly, EmitAssembly, (...)
 };
 
+/// \param suffix The file extension
+/// \return True if the file extension should be processed as fixed form
+bool isFixedFormSuffix(llvm::StringRef suffix);
+
+/// \param suffix The file extension
+/// \return True if the file extension should be processed as free form
+bool isFreeFormSuffix(llvm::StringRef suffix);
+
 inline const char *GetActionKindName(const ActionKind ak) {
   switch (ak) {
   case InputOutputTest:

flang/include/flang/FrontendTool/Utils.h

@@ -14,8 +14,6 @@
 #ifndef LLVM_FLANG_FRONTENDTOOL_UTILS_H
 #define LLVM_FLANG_FRONTENDTOOL_UTILS_H
 
-#include "llvm/ADT/StringRef.h"
-
 namespace Fortran::frontend {
 
 class CompilerInstance;
@@ -33,14 +31,6 @@ std::unique_ptr<FrontendAction> CreateFrontendAction(CompilerInstance &ci);
 /// \return - True on success.
 bool ExecuteCompilerInvocation(CompilerInstance *flang);
 
-/// \param suffix The file extension
-/// \return True if the file extension should be processed as fixed form
-bool isFixedFormSuffix(llvm::StringRef suffix);
-
-/// \param suffix The file extension
-/// \return True if the file extension should be processed as free form
-bool isFreeFormSuffix(llvm::StringRef suffix);
-
 } // end namespace Fortran::frontend
 
 #endif // LLVM_FLANG_FRONTENDTOOL_UTILS_H

flang/lib/Frontend/FrontendAction.cpp

@@ -9,6 +9,7 @@
 #include "flang/Frontend/FrontendAction.h"
 #include "flang/Frontend/CompilerInstance.h"
 #include "flang/Frontend/FrontendActions.h"
+#include "flang/Frontend/FrontendOptions.h"
 #include "flang/FrontendTool/Utils.h"
 #include "llvm/Support/Errc.h"
 

flang/lib/Frontend/FrontendOptions.cpp

@@ -7,10 +7,24 @@
 //===----------------------------------------------------------------------===//
 
 #include "flang/Frontend/FrontendOptions.h"
-#include "flang/FrontendTool/Utils.h"
 
 using namespace Fortran::frontend;
 
+bool Fortran::frontend::isFixedFormSuffix(llvm::StringRef suffix) {
+  // Note: Keep this list in-sync with flang/test/lit.cfg.py
+  return suffix == "f" || suffix == "F" || suffix == "ff" || suffix == "for" ||
+      suffix == "FOR" || suffix == "fpp" || suffix == "FPP";
+}
+
+bool Fortran::frontend::isFreeFormSuffix(llvm::StringRef suffix) {
+  // Note: Keep this list in-sync with flang/test/lit.cfg.py
+  // TODO: Add Cuda Fortan files (i.e. `*.cuf` and `*.CUF`).
+  return suffix == "f77" || suffix == "f90" || suffix == "F90" ||
+      suffix == "ff90" || suffix == "f95" || suffix == "F95" ||
+      suffix == "ff95" || suffix == "f03" || suffix == "F03" ||
+      suffix == "f08" || suffix == "F08" || suffix == "f18" || suffix == "F18";
+}
+
 InputKind FrontendOptions::GetInputKindForExtension(llvm::StringRef extension) {
   if (isFixedFormSuffix(extension) || isFreeFormSuffix(extension)) {
     return Language::Fortran;

flang/lib/FrontendTool/ExecuteCompilerInvocation.cpp

@@ -84,19 +84,4 @@ bool ExecuteCompilerInvocation(CompilerInstance *flang) {
   return success;
 }
 
-bool isFixedFormSuffix(llvm::StringRef suffix) {
-  // Note: Keep this list in-sync with flang/test/lit.cfg.py
-  return suffix == "f" || suffix == "F" || suffix == "ff" || suffix == "for" ||
-      suffix == "FOR" || suffix == "fpp" || suffix == "FPP";
-}
-
-bool isFreeFormSuffix(llvm::StringRef suffix) {
-  // Note: Keep this list in-sync with flang/test/lit.cfg.py
-  // TODO: Add Cuda Fortan files (i.e. `*.cuf` and `*.CUF`).
-  return suffix == "f77" || suffix == "f90" || suffix == "F90" ||
-      suffix == "ff90" || suffix == "f95" || suffix == "F95" ||
-      suffix == "ff95" || suffix == "f03" || suffix == "F03" ||
-      suffix == "f08" || suffix == "F08" || suffix == "f18" || suffix == "F18";
-}
-
 } // namespace Fortran::frontend