Add Enzyme (#24830)

Co-authored-by: Harmen Stoppels <harmenstoppels@gmail.com>

var/spack/repos/builtin/packages/enzyme/package.py

@@ -0,0 +1,69 @@
+
+# Copyright 2013-2020 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
+from spack import *
+
+
+class Enzyme(CMakePackage):
+    """
+    The Enzyme project is a tool for performing reverse-mode automatic
+    differentiation (AD) of statically-analyzable LLVM IR.
+    This allows developers to use Enzyme to automatically create gradients
+    of their source code without much additional work.
+    """
+
+    homepage = "https://enzyme.mit.edu"
+    url      = "https://github.com/wsmoses/Enzyme/archive/v0.0.15.tar.gz"
+    list_url = "https://github.com/wsmoses/Enzyme/releases"
+    git      = "https://github.com/wsmoses/Enzyme"
+
+    maintainers = ['wsmoses', 'vchuravy', 'tgymnich']
+
+    root_cmakelists_dir = 'enzyme'
+
+    version('main', branch='main')
+    version('0.0.15',
+            sha256='1ec27db0d790c4507b2256d851b256bf7e074eec933040e9e375d6e352a3c159')
+    version('0.0.14',
+            sha256='740641eeeeadaf47942ac88cc52e62ddc0e8c25767a501bed36ec241cf258b8d')
+    version('0.0.13',
+            sha256='d4a53964ec1f763772db2c56e6734269b7656c8b2ecd41fa7a41315bcd896b5a')
+
+    variant(
+        'build_type',
+        default='Release',
+        description='CMake build type',
+        values=('Debug', 'Release', 'RelWithDebInfo', 'MinSizeRel')
+    )
+
+    depends_on('llvm@7:12')
+    depends_on('cmake@3.9:', type='build')
+
+    def cmake_args(self):
+        spec = self.spec
+        args = [
+            "-DLLVM_DIR=" + spec["llvm"].prefix.lib + "/cmake/llvm"
+        ]
+        return args
+
+    @property
+    def libs(self):
+        ver = self.spec['llvm'].version.up_to(1)
+        libs = [
+            'LLVMEnzyme-{0}'.format(ver),
+            'ClangEnzyme-{0}'.format(ver)
+        ]
+        return find_libraries(libs, root=self.prefix, recursive=True)
+
+    def setup_dependent_build_environment(self, env, dependent_spec):
+        # Get the LLVMEnzyme and ClangEnzyme lib paths
+        llvm, clang = self.libs
+
+        if "LLVMEnzyme-" in clang:
+            llvm, clang = clang, llvm
+
+        env.set('LLVMENZYME', llvm)
+        env.set('CLANGENZYME', clang)