[flang][driver] Add standard predefinitions

[FarisRehman]

Summary

Add the following standard predefinitions that f18 supports: __flang__, __flang_major__, __flang__minor__, __flang_patchlevel__

Summary of changes:

• Populate Fortran::parser::Options#predefinitions with the default supported predefinitions

Depends on: D94422

[sameeranjoshi]

flang/lib/Frontend/CompilerInvocation.cpp

272

Why is this 1 here?
Also why only x86_64, why don't we add other architectures here?

flang/test/Flang-Driver/compiler-defined-macros.f90

25

How do you test __x86_64__ ?
I think we can add architecture specific tests in lit based test cases, does that make sense to add them here?

[awarzynski]

Thank you for working on this @FarisRehman !

@FarisRehman Re __X86_64__, in my opinion it is too early for any target-specific predefinitions and I suggest that we remove it for now. Lets revisit in the future when code-generation is supported.

@sameeranjoshi How does it sound? I totally agree with you that once we start adding such predefinitions, we should provide a solution that will support multiple architectures.

flang/lib/Frontend/CompilerInvocation.cpp

263

[nit] IMO this is fine for now, but long term the list of standard predefinitions is likely to grow significantly. Could add a TODO here? e.g.

// TODO: When expanding this list of standard predefinitions, consider creating a dedicated API for this. Also, at some point we will need to differentiate between different targets.

[sameeranjoshi]

Agreed. @awarzynski. Thank you for clarification.

[FarisRehman]

Remove target-specific predefinition

Remove a target-specific predefinition (__x86_64__), addressing review comments by @awarzynski and @sameeranjoshi

Summary of changes:

• Remove predefinition __x86_64__
• Add __flang__ to predefinitions regression test

[sameeranjoshi]

Thank you.
LGTM.

[awarzynski]

LGTM @FarisRehman , thank you!

flang/test/Flang-Driver/compiler-defined-macros.f90

1

[nit] IMHO we shouldn't be making a reference to f18 here. This test simply verifies that flang-new correctly defines macro pre-definitions for the compiler version. Perhaps the file could be renamed to reflect that?

flang/lib/Frontend/CompilerInvocation.cpp

 //===- CompilerInvocation.cpp ---------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #include "flang/Frontend/CompilerInvocation.h"
 #include "flang/Frontend/PreprocessorOptions.h"
+#include "flang/Version.inc"
 #include "clang/Basic/AllDiagnostics.h"
 #include "clang/Basic/DiagnosticDriver.h"
 #include "clang/Basic/DiagnosticOptions.h"
 #include "clang/Driver/DriverDiagnostic.h"
 #include "clang/Driver/Options.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/Option/Arg.h"

 
 void CompilerInvocation::SetDefaultFortranOpts() {
   auto &fortranOptions = fortranOpts();
 
   // These defaults are based on the defaults in f18/f18.cpp.
   std::vector<std::string> searchDirectories{"."s};
   fortranOptions.searchDirectories = searchDirectories;
   fortranOptions.isFixedForm = false;
+
+  // Populate the macro list with version numbers and other predefinitions.
+  // TODO: When expanding this list of standard predefinitions, consider
+  // creating a dedicated API for this. Also at some point we will need to
+  // differentiate between different targets.
+  fortranOptions.predefinitions.emplace_back("__flang__", "1");
+  fortranOptions.predefinitions.emplace_back(
+      "__flang_major__", FLANG_VERSION_MAJOR_STRING);
+  fortranOptions.predefinitions.emplace_back(
+      "__flang_minor__", FLANG_VERSION_MINOR_STRING);
+  fortranOptions.predefinitions.emplace_back(
+      "__flang_patchlevel__", FLANG_VERSION_PATCHLEVEL_STRING);
 }
 
 void CompilerInvocation::setFortranOpts() {
   auto &fortranOptions = fortranOpts();
   const auto &preprocessorOptions = preprocessorOpts();
 
   collectMacroDefinitions(preprocessorOptions, fortranOptions);
 
   fortranOptions.searchDirectories.insert(
       fortranOptions.searchDirectories.end(),
       preprocessorOptions.searchDirectoriesFromDashI.begin(),
       preprocessorOptions.searchDirectoriesFromDashI.end());
 }

flang/test/Flang-Driver/compiler-defined-macros.f90

+! Check that the driver supports the standard predefinitions that f18 does.
+
+! REQUIRES: new-flang-driver
+
+!--------------------------
+! FLANG DRIVER (flang-new)
+!--------------------------
+! RUN: %flang-new -E %s  2>&1 | FileCheck %s --ignore-case
+
+!-----------------------------------------
+! FRONTEND FLANG DRIVER (flang-new -fc1)
+!-----------------------------------------
+! RUN: %flang-new -fc1 -E %s  2>&1 | FileCheck %s --ignore-case
+
+!-----------------
+! EXPECTED OUTPUT
+!-----------------
+! CHECK: flang = 1
+! CHECK: flang_major = {{[1-9][0-9]*$}}
+! CHECK: flang_minor = {{[0-9]+$}}
+! CHECK: flang_patchlevel = {{[0-9]+$}}
+
+integer, parameter :: flang = __flang__
+integer, parameter :: flang_major = __flang_major__
+integer, parameter :: flang_minor = __flang_minor__
+integer, parameter :: flang_patchlevel = __flang_patchlevel__