add emsdk package

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

@@ -0,0 +1,58 @@
+# Copyright 2013-2022 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)
+
+import re
+import sys
+
+from spack import *
+
+
+class Emsdk(Package):
+    """Emscripten SDK"""
+
+    homepage = "https://emscripten.org"
+    git      = "https://github.com/emscripten-core/emsdk.git"
+
+    version('main')
+    version('3.1.8',  tag='3.1.8')
+    version('2.0.34', tag='2.0.34')
+    version('1.40.1', tag='1.40.1')
+
+    depends_on('python@3')
+    depends_on('cmake', type='test')
+
+    # TODO: use our own llvm and node instead by overriding NODE_JS and LLVM_ROOT in the
+    # generated .emscripten file? See
+    # https://emscripten.org/docs/getting_started/downloads.html#linux
+
+    phases = ['install']
+
+    def install(self, spec, prefix):
+        # See https://emscripten.org/docs/getting_started/downloads.html#emsdk-install-targets.
+        if str(self.version) == 'main':
+            version_arg = 'latest'
+        else:
+            version_arg = str(self.version)
+
+        emsdk_script = Executable('./emsdk')
+        emsdk_script('install', version_arg)
+        emsdk_script('activate', version_arg)
+
+        install_tree('.', prefix)
+
+    def setup_run_environment(self, env):
+        """Parse the output of the environment setup script from the emscripten SDK."""
+        sh = which('sh')
+        with working_dir(self.prefix):
+            sh_output = sh('./emsdk_env.sh', output=str, error=str)
+
+        env_pairs_yet = False
+        for line in sh_output.splitlines():
+            if not env_pairs_yet:
+                if line == 'Setting environment variables:':
+                    env_pairs_yet = True
+                continue
+            (env_var, var_value) = re.match(r'^([A-Z_]+) = (.*)$', line).groups()
+            env.set(env_var, var_value)