Create Fortran bindings module

enzyme/CMakeLists.txt

@@ -34,10 +34,12 @@ set(CMAKE_CXX_STANDARD_REQUIRED ON)
 option(ENZYME_ENABLE_PLUGINS "Enable Clang/LLD/Opt plugins" ON)
 option(ENZYME_ENABLE_BENCHMARKS "Enable benchmarks" OFF)
 option(ENZYME_BC_LOADER "Enable bitcode loader" ON)
+option(ENZYME_FORTRAN "Build Enzyme Fortran bindings" OFF)
 option(ENZYME_CLANG "Build enzyme clang plugin" ON)
 option(ENZYME_FLANG "Build enzyme flang symlink" OFF)
 option(ENZYME_MLIR "Build enzyme mlir plugin" OFF)
 option(ENZYME_IFX "Enable enzyme support for the Intel Fortran compiler IFX" OFF)
+option(ENZYME_IFX "Enable enzyme support for the Intel Fortran compiler IFX" OFF)
 option(ENZYME_EXTERNAL_SHARED_LIB "Build external shared library" OFF)
 option(ENZYME_APPLE_DYNAMIC_LOOKUP
   "On Apple, link Enzyme shared library with -flat_namespace/-undefined,dynamic_lookup instead of linking LLVM"
@@ -299,6 +301,9 @@ endif()
 if (ENZYME_ENABLE_PLUGINS)
     add_subdirectory(test)
 endif()
+if (ENZYME_FORTRAN)
+    add_subdirectory(Fortran)
+endif()
 
 # The benchmarks data are not in git-exported source archives to minimize size.
 # Only add the benchmarks if the directory exists.

enzyme/Fortran/CMakeLists.txt

@@ -0,0 +1,26 @@
+enable_language(Fortran)
+include(FortranCInterface)
+FortranCInterface_VERIFY(QUIET)
+
+add_library(EnzymeFortran enzyme.f90)
+
+# Install library, create target file
+install(
+  TARGETS EnzymeFortran
+  EXPORT EnzymeFortranTargets
+  LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}"
+  PUBLIC_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
+  PRIVATE_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
+  INCLUDES
+  DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/EnzymeFortran)
+
+# Install Fortran module file
+if(NOT DEFINED CMAKE_INSTALL_MODULEDIR)
+  set(
+    CMAKE_INSTALL_MODULEDIR
+    "${CMAKE_INSTALL_INCLUDEDIR}/EnzymeFortran"
+    CACHE STRING "Directory in prefix to install generated module files"
+  )
+endif()
+install(FILES "${CMAKE_Fortran_MODULE_DIRECTORY}/enzyme.mod"
+        DESTINATION "${CMAKE_INSTALL_MODULEDIR}")

enzyme/Fortran/enzyme.f90

@@ -0,0 +1,36 @@
+! ===- enzyme.f90 - Fortran bindings for Enzyme ---------------------------=== !
+!
+!                              Enzyme Project
+!
+!  Part of the Enzyme 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
+!
+!  If using this code in an academic setting, please cite the following:
+!  @misc{enzymeGithub,
+!   author = {William S. Moses and Valentin Churavy},
+!   title = {Enzyme: High Performance Automatic Differentiation of LLVM},
+!   year = {2020},
+!   howpublished = {\url{https://github.com/wsmoses/Enzyme}},
+!   note = {commit xxxxxxx}
+!  }
+!
+! ===----------------------------------------------------------------------=== !
+!
+!  This file provides Fortran bindings for Enzyme.
+!
+! ===----------------------------------------------------------------------=== !
+module enzyme
+  use iso_c_binding, only: c_int
+  implicit none
+  private
+
+  ! Bindings for activity descriptors
+  integer(c_int), public, bind(C, name="enzyme_const")     :: enzyme_const
+  integer(c_int), public, bind(C, name="enzyme_dup")       :: enzyme_dup
+  integer(c_int), public, bind(C, name="enzyme_dupnoneed") :: enzyme_dupnoneed
+  integer(c_int), public, bind(C, name="enzyme_out")       :: enzyme_out
+  integer(c_int), public, bind(C, name="enzyme_scalar")    :: enzyme_scalar
+  integer(c_int), public, bind(C, name="enzyme_width")     :: enzyme_width
+  integer(c_int), public, bind(C, name="enzyme_vector")    :: enzyme_vector
+end module enzyme