[flang][driver] Add extension options and -finput-charset

Add the following options:
* -fimplicit-none and -fno-implicit-none
* -fbackslash and -fno-backslash
* -flogical-abbreviations and -fno-logical-abbreviations
* -fxor-operator and -fno-xor-operator
* -falternative-parameter-statement
* -finput-charset=<value>

Summary of changes:
- Enable extensions in CompilerInvocation#ParseFrontendArgs
- Add encoding_ to Fortran::frontend::FrontendOptions
- Add encoding to Fortran::parser::Options

Differential Revision: https://reviews.llvm.org/D96407

clang/include/clang/Driver/Options.td

@@ -1714,7 +1714,8 @@ def fexperimental_strict_floating_point : Flag<["-"], "fexperimental-strict-floa
   Group<f_clang_Group>, Flags<[CC1Option]>,
   HelpText<"Enables experimental strict floating point in LLVM.">,
   MarshallingInfoFlag<LangOpts<"ExpStrictFP">>;
-def finput_charset_EQ : Joined<["-"], "finput-charset=">, Group<f_Group>;
+def finput_charset_EQ : Joined<["-"], "finput-charset=">, Flags<[FlangOption, FC1Option]>, Group<f_Group>,
+  HelpText<"Specify the default character set for source files">;
 def fexec_charset_EQ : Joined<["-"], "fexec-charset=">, Group<f_Group>;
 def finstrument_functions : Flag<["-"], "finstrument-functions">, Group<f_Group>, Flags<[CC1Option]>,
   HelpText<"Generate calls to instrument function entry and exit">,
@@ -4170,7 +4171,6 @@ defm aggressive_function_elimination : BooleanFFlag<"aggressive-function-elimina
 defm align_commons : BooleanFFlag<"align-commons">, Group<gfortran_Group>;
 defm all_intrinsics : BooleanFFlag<"all-intrinsics">, Group<gfortran_Group>;
 defm automatic : BooleanFFlag<"automatic">, Group<gfortran_Group>;
-defm backslash : BooleanFFlag<"backslash">, Group<gfortran_Group>;
 defm backtrace : BooleanFFlag<"backtrace">, Group<gfortran_Group>;
 defm bounds_check : BooleanFFlag<"bounds-check">, Group<gfortran_Group>;
 defm check_array_temporaries : BooleanFFlag<"check-array-temporaries">, Group<gfortran_Group>;
@@ -4187,7 +4187,6 @@ defm dump_parse_tree : BooleanFFlag<"dump-parse-tree">, Group<gfortran_Group>;
 defm external_blas : BooleanFFlag<"external-blas">, Group<gfortran_Group>;
 defm f2c : BooleanFFlag<"f2c">, Group<gfortran_Group>;
 defm frontend_optimize : BooleanFFlag<"frontend-optimize">, Group<gfortran_Group>;
-defm implicit_none : BooleanFFlag<"implicit-none">, Group<gfortran_Group>;
 defm init_local_zero : BooleanFFlag<"init-local-zero">, Group<gfortran_Group>;
 defm integer_4_integer_8 : BooleanFFlag<"integer-4-integer-8">, Group<gfortran_Group>;
 defm intrinsic_modules_path : BooleanFFlag<"intrinsic-modules-path">, Group<gfortran_Group>;
@@ -4241,6 +4240,22 @@ file}]>;
 def ffixed_line_length_VALUE : Joined<["-"], "ffixed-line-length-">, Group<f_Group>, Alias<ffixed_line_length_EQ>;
 def fopenacc : Flag<["-"], "fopenacc">, Group<f_Group>,
   HelpText<"Enable OpenACC">;
+def fbackslash : Flag<["-"], "fbackslash">, Group<f_Group>,
+  HelpText<"Specify that backslash in string introduces an escape character">,
+  DocBrief<[{Change the interpretation of backslashes in string literals from
+a single backslash character to "C-style" escape characters.}]>;
+def fno_backslash : Flag<["-"], "fno-backslash">, Group<f_Group>;
+def fxor_operator : Flag<["-"], "fxor-operator">, Group<f_Group>,
+  HelpText<"Enable .XOR. as a synonym of .NEQV.">;
+def fno_xor_operator : Flag<["-"], "fno-xor-operator">, Group<f_Group>;
+def flogical_abbreviations : Flag<["-"], "flogical-abbreviations">, Group<f_Group>,
+  HelpText<"Enable logical abbreviations">;
+def fno_logical_abbreviations : Flag<["-"], "fno-logical-abbreviations">, Group<f_Group>;
+def fimplicit_none : Flag<["-"], "fimplicit-none">, Group<f_Group>,
+  HelpText<"No implicit typing allowed unless overridden by IMPLICIT statements">;
+def fno_implicit_none : Flag<["-"], "fno-implicit-none">, Group<f_Group>;
+def falternative_parameter_statement : Flag<["-"], "falternative-parameter-statement">, Group<f_Group>,
+  HelpText<"Enable the old style PARAMETER statement">;
 
 }
 

clang/lib/Driver/ToolChains/Flang.cpp

@@ -21,9 +21,16 @@ using namespace llvm::opt;
 
 void Flang::AddFortranDialectOptions(const ArgList &Args,
                                      ArgStringList &CmdArgs) const {
-  Args.AddAllArgs(CmdArgs, {options::OPT_ffixed_form, options::OPT_ffree_form,
-                            options::OPT_ffixed_line_length_EQ,
-                            options::OPT_fopenmp, options::OPT_fopenacc});
+  Args.AddAllArgs(CmdArgs,
+                  {options::OPT_ffixed_form, options::OPT_ffree_form,
+                   options::OPT_ffixed_line_length_EQ, options::OPT_fopenmp,
+                   options::OPT_fopenacc, options::OPT_finput_charset_EQ,
+                   options::OPT_fimplicit_none, options::OPT_fno_implicit_none,
+                   options::OPT_fbackslash, options::OPT_fno_backslash,
+                   options::OPT_flogical_abbreviations,
+                   options::OPT_fno_logical_abbreviations,
+                   options::OPT_fxor_operator, options::OPT_fno_xor_operator,
+                   options::OPT_falternative_parameter_statement});
 }
 
 void Flang::AddPreprocessingOptions(const ArgList &Args,

flang/include/flang/Frontend/FrontendOptions.h

@@ -9,6 +9,7 @@
 #define LLVM_FLANG_FRONTEND_FRONTENDOPTIONS_H
 
 #include "flang/Common/Fortran-features.h"
+#include "flang/Parser/characters.h"
 #include "flang/Parser/unparse.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/MemoryBuffer.h"
@@ -174,6 +175,9 @@ class FrontendOptions {
   // Language features
   common::LanguageFeatureControl features_;
 
+  // Source file encoding
+  Fortran::parser::Encoding encoding_{Fortran::parser::Encoding::UTF_8};
+
 public:
   FrontendOptions() : showHelp_(false), showVersion_(false) {}
 

flang/include/flang/Parser/parsing.h

@@ -36,6 +36,7 @@ struct Options {
   bool instrumentedParse{false};
   bool isModuleFile{false};
   bool needProvenanceRangeToCharBlockMappings{false};
+  Fortran::parser::Encoding encoding{Fortran::parser::Encoding::UTF_8};
 };
 
 class Parsing {

flang/lib/Frontend/CompilerInstance.cpp

@@ -145,6 +145,8 @@ bool CompilerInstance::ExecuteAction(FrontendAction &act) {
   invoc.setDefaultPredefinitions();
   // Update the fortran options based on user-based input.
   invoc.setFortranOpts();
+  // Set the encoding to read all input files in based on user input.
+  allSources_->set_encoding(invoc.fortranOpts().encoding);
   // Create the semantics context and set semantic options.
   invoc.setSemanticsOpts(*this->allCookedSources_);
 

flang/lib/Frontend/CompilerInvocation.cpp

@@ -213,6 +213,49 @@ static InputKind ParseFrontendArgs(FrontendOptions &opts,
   if (args.hasArg(clang::driver::options::OPT_fopenmp)) {
     opts.features_.Enable(Fortran::common::LanguageFeature::OpenMP);
   }
+  if (const llvm::opt::Arg *arg =
+          args.getLastArg(clang::driver::options::OPT_fimplicit_none,
+              clang::driver::options::OPT_fno_implicit_none)) {
+    opts.features_.Enable(
+        Fortran::common::LanguageFeature::ImplicitNoneTypeAlways,
+        arg->getOption().matches(clang::driver::options::OPT_fimplicit_none));
+  }
+  if (const llvm::opt::Arg *arg =
+          args.getLastArg(clang::driver::options::OPT_fbackslash,
+              clang::driver::options::OPT_fno_backslash)) {
+    opts.features_.Enable(Fortran::common::LanguageFeature::BackslashEscapes,
+        arg->getOption().matches(clang::driver::options::OPT_fbackslash));
+  }
+  if (const llvm::opt::Arg *arg =
+          args.getLastArg(clang::driver::options::OPT_flogical_abbreviations,
+              clang::driver::options::OPT_fno_logical_abbreviations)) {
+    opts.features_.Enable(
+        Fortran::common::LanguageFeature::LogicalAbbreviations,
+        arg->getOption().matches(
+            clang::driver::options::OPT_flogical_abbreviations));
+  }
+  if (const llvm::opt::Arg *arg =
+          args.getLastArg(clang::driver::options::OPT_fxor_operator,
+              clang::driver::options::OPT_fno_xor_operator)) {
+    opts.features_.Enable(Fortran::common::LanguageFeature::XOROperator,
+        arg->getOption().matches(clang::driver::options::OPT_fxor_operator));
+  }
+  if (args.hasArg(
+          clang::driver::options::OPT_falternative_parameter_statement)) {
+    opts.features_.Enable(Fortran::common::LanguageFeature::OldStyleParameter);
+  }
+  if (const llvm::opt::Arg *arg =
+          args.getLastArg(clang::driver::options::OPT_finput_charset_EQ)) {
+    llvm::StringRef argValue = arg->getValue();
+    if (argValue == "utf-8") {
+      opts.encoding_ = Fortran::parser::Encoding::UTF_8;
+    } else if (argValue == "latin-1") {
+      opts.encoding_ = Fortran::parser::Encoding::LATIN_1;
+    } else {
+      diags.Report(clang::diag::err_drv_invalid_value)
+          << arg->getAsString(args) << argValue;
+    }
+  }
   return dashX;
 }
 
@@ -376,6 +419,7 @@ void CompilerInvocation::setFortranOpts() {
   fortranOptions.fixedFormColumns = frontendOptions.fixedFormColumns_;
 
   fortranOptions.features = frontendOptions.features_;
+  fortranOptions.encoding = frontendOptions.encoding_;
 
   collectMacroDefinitions(preprocessorOptions, fortranOptions);
 

flang/test/Flang-Driver/driver-help-hidden.f90

@@ -22,14 +22,21 @@
 ! CHECK-NEXT: -c        Only run preprocess, compile, and assemble steps
 ! CHECK-NEXT: -D <macro>=<value>     Define <macro> to <value> (or 1 if <value> omitted)
 ! CHECK-NEXT: -E        Only run the preprocessor
+! CHECK-NEXT: -falternative-parameter-statement
+! CHECK-NEXT: Enable the old style PARAMETER statement
+! CHECK-NEXT: -fbackslash            Specify that backslash in string introduces an escape character
 ! CHECK-NEXT: -fcolor-diagnostics    Enable colors in diagnostics
 ! CHECK-NEXT: -ffixed-form           Process source files in fixed form
 ! CHECK-NEXT: -ffixed-line-length=<value>
 ! CHECK-NEXT: Use <value> as character line width in fixed mode
 ! CHECK-NEXT: -ffree-form            Process source files in free form
+! CHECK-NEXT: -fimplicit-none        No implicit typing allowed unless overridden by IMPLICIT statements
+! CHECK-NEXT: -finput-charset=<value> Specify the default character set for source files
+! CHECK-NEXT: -flogical-abbreviations Enable logical abbreviations
 ! CHECK-NEXT: -fno-color-diagnostics Disable colors in diagnostics
 ! CHECK-NEXT: -fopenacc              Enable OpenACC
 ! CHECK-NEXT: -fopenmp               Parse OpenMP pragmas and generate parallel code.
+! CHECK-NEXT: -fxor-operator         Enable .XOR. as a synonym of .NEQV.
 ! CHECK-NEXT: -help     Display available options
 ! CHECK-NEXT: -I <dir>               Add directory to the end of the list of include search paths
 ! CHECK-NEXT: -module-dir <dir>      Put MODULE files in <dir>

flang/test/Flang-Driver/driver-help.f90

@@ -22,14 +22,21 @@
 ! HELP-NEXT: -c                     Only run preprocess, compile, and assemble steps
 ! HELP-NEXT: -D <macro>=<value>     Define <macro> to <value> (or 1 if <value> omitted)
 ! HELP-NEXT: -E                     Only run the preprocessor
+! HELP-NEXT: -falternative-parameter-statement
+! HELP-NEXT: Enable the old style PARAMETER statement
+! HELP-NEXT: -fbackslash            Specify that backslash in string introduces an escape character
 ! HELP-NEXT: -fcolor-diagnostics    Enable colors in diagnostics
 ! HELP-NEXT: -ffixed-form           Process source files in fixed form
 ! HELP-NEXT: -ffixed-line-length=<value>
 ! HELP-NEXT: Use <value> as character line width in fixed mode
 ! HELP-NEXT: -ffree-form            Process source files in free form
+! HELP-NEXT: -fimplicit-none        No implicit typing allowed unless overridden by IMPLICIT statements
+! HELP-NEXT: -finput-charset=<value> Specify the default character set for source files
+! HELP-NEXT: -flogical-abbreviations Enable logical abbreviations
 ! HELP-NEXT: -fno-color-diagnostics Disable colors in diagnostics
 ! HELP-NEXT: -fopenacc              Enable OpenACC
 ! HELP-NEXT: -fopenmp               Parse OpenMP pragmas and generate parallel code.
+! HELP-NEXT: -fxor-operator         Enable .XOR. as a synonym of .NEQV.
 ! HELP-NEXT: -help                  Display available options
 ! HELP-NEXT: -I <dir>               Add directory to the end of the list of include search paths
 ! HELP-NEXT: -module-dir <dir>      Put MODULE files in <dir>
@@ -46,15 +53,22 @@
 ! HELP-FC1-NEXT: -D <macro>=<value>     Define <macro> to <value> (or 1 if <value> omitted)
 ! HELP-FC1-NEXT: -emit-obj Emit native object files
 ! HELP-FC1-NEXT: -E                     Only run the preprocessor
+! HELP-FC1-NEXT: -falternative-parameter-statement
+! HELP-FC1-NEXT: Enable the old style PARAMETER statement
+! HELP-FC1-NEXT: -fbackslash            Specify that backslash in string introduces an escape character
 ! HELP-FC1-NEXT: -fdebug-unparse-with-symbols
 ! HELP-FC1-NEXT:                        Unparse and stop.
 ! HELP-FC1-NEXT: -fdebug-unparse        Unparse and stop.
 ! HELP-FC1-NEXT: -ffixed-form           Process source files in fixed form
 ! HELP-FC1-NEXT: -ffixed-line-length=<value>
 ! HELP-FC1-NEXT: Use <value> as character line width in fixed mode
 ! HELP-FC1-NEXT: -ffree-form            Process source files in free form
+! HELP-FC1-NEXT: -fimplicit-none        No implicit typing allowed unless overridden by IMPLICIT statements
+! HELP-FC1-NEXT: -finput-charset=<value> Specify the default character set for source files
+! 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>

flang/test/Flang-Driver/escaped-backslash.f90

@@ -0,0 +1,35 @@
+! Ensure argument -fbackslash works as expected.
+
+! REQUIRES: new-flang-driver
+
+!--------------------------
+! FLANG DRIVER (flang-new)
+!--------------------------
+! RUN: %flang-new -E %s  2>&1 | FileCheck %s --check-prefix=ESCAPED
+! RUN: %flang-new -E -fbackslash -fno-backslash %s  2>&1 | FileCheck %s --check-prefix=ESCAPED
+! RUN: %flang-new -E -fbackslash %s  2>&1 | FileCheck %s --check-prefix=UNESCAPED
+
+!-----------------------------------------
+! FRONTEND FLANG DRIVER (flang-new -fc1)
+!-----------------------------------------
+! RUN: %flang-new -fc1 -E %s  2>&1 | FileCheck %s --check-prefix=ESCAPED
+! RUN: %flang-new -fc1 -E -fbackslash -fno-backslash %s  2>&1 | FileCheck %s --check-prefix=ESCAPED
+! RUN: %flang-new -fc1 -E -fbackslash %s  2>&1 | FileCheck %s --check-prefix=UNESCAPED
+
+!-----------------------------------------
+! EXPECTED OUTPUT FOR ESCAPED BACKSLASHES
+!-----------------------------------------
+! ESCAPED:program backslash
+! ESCAPED-NEXT:New\\nline
+! ESCAPED-NOT:New\nline
+
+!-------------------------------------------
+! EXPECTED OUTPUT FOR UNESCAPED BACKSLASHES
+!-------------------------------------------
+! UNESCAPED:program backslash
+! UNESCAPED-NEXT:New\nline
+! UNESCAPED-NOT:New\\nline
+
+program Backslash
+    print *, 'New\nline'
+end

flang/test/Flang-Driver/frontend-forwarding.f90

@@ -0,0 +1,10 @@
+! Test that flang-new forwards Flang frontend
+! options to flang-new -fc1 as expected.
+
+! REQUIRES: new-flang-driver
+
+! RUN: %flang-new -fsyntax-only -### %s -o %t 2>&1 \
+! RUN:     -finput-charset=utf-8 \
+! RUN:   | FileCheck %s
+
+! CHECK: "-finput-charset=utf-8"

flang/test/Flang-Driver/implicit-none.f90

@@ -0,0 +1,32 @@
+! Ensure argument -fimplicit-none works as expected.
+
+! REQUIRES: new-flang-driver
+
+!--------------------------
+! FLANG DRIVER (flang-new)
+!--------------------------
+! RUN: %flang-new -fsyntax-only %s  2>&1 | FileCheck %s --allow-empty --check-prefix=DEFAULT
+! RUN: %flang-new -fsyntax-only -fimplicit-none -fno-implicit-none %s  2>&1 | FileCheck %s --allow-empty --check-prefix=DEFAULT
+! RUN: not %flang-new -fsyntax-only -fimplicit-none %s  2>&1 | FileCheck %s --check-prefix=WITH_IMPL_NONE
+
+!-----------------------------------------
+! FRONTEND FLANG DRIVER (flang-new -fc1)
+!-----------------------------------------
+! RUN: %flang-new -fc1 -fsyntax-only %s  2>&1 | FileCheck %s --allow-empty --check-prefix=DEFAULT
+! RUN: %flang-new -fc1 -fsyntax-only -fimplicit-none -fno-implicit-none %s  2>&1 | FileCheck %s --allow-empty --check-prefix=DEFAULT
+! RUN: not %flang-new -fc1 -fsyntax-only -fimplicit-none %s  2>&1 | FileCheck %s --check-prefix=WITH_IMPL_NONE
+
+!--------------------------------------
+! EXPECTED OUTPUT FOR NO IMPLICIT NONE
+!--------------------------------------
+! DEFAULT-NOT:error
+
+!------------------------------------------
+! EXPECTED OUTPUT FOR IMPLICIT NONE ALWAYS
+!------------------------------------------
+! WITH_IMPL_NONE:No explicit type declared for 'a'
+! WITH_IMPL_NONE:No explicit type declared for 'b'
+
+function a()
+  a = b
+end

flang/test/Semantics/oldparam02.f90

@@ -1,4 +1,4 @@
-! RUN: not %f18 -falternative-parameter-statement -fdebug-dump-symbols %s 2>&1 | FileCheck %s
+! RUN: not %flang -falternative-parameter-statement -fsyntax-only %s 2>&1 | FileCheck %s
 
 ! Error tests for "old style" PARAMETER statements
 subroutine subr(x1,x2,x3,x4,x5)

flang/test/Semantics/resolve64.f90

@@ -1,4 +1,4 @@
-! RUN: %S/test_errors.sh %s %t %f18 -flogical-abbreviations -fxor-operator
+! RUN: %S/test_errors.sh %s %t %flang -flogical-abbreviations -fxor-operator
 
 ! Like m4 in resolve63 but compiled with different options.
 ! Alternate operators are enabled so treat these as intrinsic.