# Copyright (c) 2013, 2015-2017 ARM Limited
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# Copyright (c) 2011 Advanced Micro Devices, Inc.
# Copyright (c) 2009 The Hewlett-Packard Development Company
# Copyright (c) 2004-2005 The Regents of The University of Michigan
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# modification, are permitted provided that the following conditions are
# met: redistributions of source code must retain the above copyright
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import os

from gem5_python_paths import extra_python_paths

def EnvDefaults(env):
    # export TERM so that clang reports errors in color
    use_vars = set([ 'AS', 'AR', 'CC', 'CXX', 'HOME', 'LD_LIBRARY_PATH',
                     'LIBRARY_PATH', 'PATH', 'PKG_CONFIG_PATH', 'PROTOC',
                     'PYTHONPATH', 'RANLIB', 'TERM', 'PYTHON_CONFIG',
                     'CCFLAGS_EXTRA', 'GEM5PY_CCFLAGS_EXTRA',
                     'GEM5PY_LINKFLAGS_EXTRA', 'LINKFLAGS_EXTRA', 'LANG'])

    use_prefixes = [
        "ASAN_",           # address sanitizer symbolizer path and settings
        "CCACHE_",         # ccache (caching compiler wrapper) configuration
        "CCC_",            # clang static analyzer configuration
        "DISTCC_",         # distcc (distributed compiler wrapper) config
        "INCLUDE_SERVER_", # distcc pump server settings
        "M5",              # M5 configuration (e.g., path to kernels)
        "NIX_",            # wrapped binaries if using nix package manager
        ]

    for key,val in sorted(os.environ.items()):
        if key in use_vars or \
                any([key.startswith(prefix) for prefix in use_prefixes]):
            env['ENV'][key] = val

    # These variables from the environment override/become SCons variables,
    # with a default if they weren't in the host environment.
    var_overrides = {
        'CC': env['CC'],
        'CXX': env['CXX'],
        'PROTOC': 'protoc',
        'PYTHON_CONFIG': [ 'python3-config', 'python-config' ],
        'CCFLAGS_EXTRA': '',
        'GEM5PY_CCFLAGS_EXTRA': '',
        'GEM5PY_LINKFLAGS_EXTRA': '',
        'LINKFLAGS_EXTRA': '',
    }
    for key,default in var_overrides.items():
        env[key] = env['ENV'].get(key, default)

    # Tell scons to avoid implicit command dependencies to avoid issues
    # with the param wrappes being compiled twice (see
    # https://github.com/SCons/scons/issues/2811
    env['IMPLICIT_COMMAND_DEPENDENCIES'] = 0
    env.Decider('MD5-timestamp')

    # add useful python code PYTHONPATH so it can be used by subprocesses
    # as well
    env.AppendENVPath('PYTHONPATH', extra_python_paths)

    # Default duplicate option is to use hard links, but this messes up
    # when you use emacs to edit a file in the target dir, as emacs moves
    # file to file~ then copies to file, breaking the link.  Symbolic
    # (soft) links work better.
    env.SetOption('duplicate', 'soft-copy')