src/SConscript

# -*- mode:python -*-

# Copyright (c) 2018, 2020 ARM Limited
#
# The license below extends only to copyright in the software and shall
# not be construed as granting a license to any other intellectual
# property including but not limited to intellectual property relating
# to a hardware implementation of the functionality of the software
# licensed hereunder.  You may use the software subject to the license
# terms below provided that you ensure that this notice is replicated
# unmodified and in its entirety in all distributions of the software,
# modified or unmodified, in source code or in binary form.
#
# Copyright (c) 2004-2005 The Regents of The University of Michigan
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met: redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer;
# redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution;
# neither the name of the copyright holders nor the names of its
# contributors may be used to endorse or promote products derived from
# this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

import collections
import distutils.spawn
import itertools
import os
import os.path
import re
import sys

import SCons

from gem5_scons import Transform, warning, error, ToValue, FromValue
from gem5_scons.sources import *

Export(SourceFilter.factories)

# This file defines how to build a particular configuration of gem5
# based on variable settings in the 'env' build environment.

Import('*')

if env['USE_EFENCE']:
    env.Append(LIBS=['efence'])

# Children need to see the environment
Export('env')

all_export_vars = set()
all_export_vars.update(export_vars)
all_export_vars.update(sticky_vars.keys())

build_env = [(opt, env[opt]) for opt in all_export_vars]

from code_formatter import code_formatter

def GdbXml(xml_id, symbol, tags=None, add_tags=None):
    cc, hh = env.Blob(symbol, xml_id)
    Source(cc, tags=tags, add_tags=add_tags)

class Source(SourceFile):
    pass

class SourceLib(SourceItem):
    pass

build_tools = Dir('#build_tools')

# Build a small helper that runs Python code using the same version of Python
# as gem5. This is in an unorthodox location to avoid building it for every
# variant.
gem5py_env = gem5py_env.Clone()
gem5py = gem5py_env.File('gem5py')
gem5py_m5 = gem5py_env.File('gem5py_m5')
gem5py_env['GEM5PY'] = gem5py
gem5py_env['GEM5PY_M5'] = gem5py_m5
gem5py_env['OBJSUFFIX'] = '.pyo'
# Inject build_tools into PYTHONPATH for when we run gem5py.
pythonpath = gem5py_env['ENV'].get('PYTHONPATH', '').split(':')
pythonpath.append(build_tools.abspath)
gem5py_env['ENV']['PYTHONPATH'] = ':'.join(pythonpath)

class PySource(SourceFile):
    '''Add a python source file to the named package'''
    def __init__(self, package, source, tags=None, add_tags=None):
        '''specify the python package, the source file, and any tags'''
        super().__init__(source, tags, add_tags)

        basename = os.path.basename(self.filename)
        modname, ext = os.path.splitext(basename)
        assert ext == '.py'

        if package:
            modpath = package.split('.')
        else:
            modpath = []

        if modname != '__init__':
            modpath += [ modname ]
        modpath = '.'.join(modpath)

        abspath = self.snode.abspath
        if not os.path.exists(abspath):
            abspath = self.tnode.abspath

        self.modpath = modpath

        cpp = File(self.filename + '.cc')

        overrides = {
            'PYSOURCE_MODPATH': modpath,
            'PYSOURCE_ABSPATH': abspath,
            'PYSOURCE': File(source),
            'MARSHAL_PY': build_tools.File('marshal.py')
        }
        gem5py_env.Command(cpp,
            [ '${PYSOURCE}', '${GEM5PY}', '${MARSHAL_PY}' ],
            MakeAction('"${GEM5PY}" "${MARSHAL_PY}" "${TARGET}" ' \
                       '"${PYSOURCE}" "${PYSOURCE_MODPATH}" ' \
                       '"${PYSOURCE_ABSPATH}"',
                       Transform("EMBED PY", max_sources=1)),
            **overrides)
        Source(cpp, tags=self.tags, add_tags=['python', 'm5_module'])

class SimObject(PySource):
    '''Add a SimObject python file as a python source object and add
    it to a list of sim object modules'''

    def __init__(self, source, *, sim_objects=None, enums=None,
            tags=None, add_tags=None):
        '''Specify the source file and any tags (automatically in
        the m5.objects package)'''
        if sim_objects is None:
            if enums is None:
                error(f"SimObject({source}...) must list c++ sim_objects or "
                      "enums (set either to [] if there are none).")
            sim_objects = []
        if enums is None:
            enums = []

        super().__init__('m5.objects', source, tags, add_tags)

        build_dir = Dir(env['BUILDDIR'])
        module = self.modpath

        # Generate all of the SimObject param C++ files.
        for simobj in sim_objects:
            # Some helper functions
            srcs = [ Value(module), Value(simobj),
                    "${GEM5PY_M5}", "${PYSCRIPT}" ]
            def cmdline(*args):
                all_args = [ 'GEM5PY_M5', 'PYSCRIPT', 'MODULE' ] + list(args)
                return ' '.join(list('"${%s}"' % arg for arg in all_args))

            # Params header.
            gem5py_env.Command([ "${PARAMS_HH}" ], srcs,
                    MakeAction(cmdline('PARAMS_HH'), Transform("SO Param", 2)),
                    MODULE=module,
                    SIMOBJ=simobj,
                    PYSCRIPT=build_tools.File('sim_object_param_struct_hh.py'),
                    PARAMS_HH=build_dir.File(f'params/{simobj}.hh'))

            # Params cc.
            cc_file = build_dir.File(f'python/_m5/param_{simobj}.cc')
            gem5py_env.Command([ "${PARAMS_CC}" ], srcs,
                    MakeAction(cmdline('PARAMS_CC', 'USE_PYTHON'),
                        Transform("SO Param", 2)),
                    PYSCRIPT=build_tools.File('sim_object_param_struct_cc.py'),
                    MODULE=module,
                    SIMOBJ=simobj,
                    PARAMS_CC=cc_file,
                    USE_PYTHON=env['USE_PYTHON'])
            Source(cc_file, tags=self.tags, add_tags='python')

            # CXX config header.
            gem5py_env.Command([ "${CXXCONFIG_HH}" ], srcs,
                    MakeAction(cmdline('CXXCONFIG_HH'),
                        Transform("CXXCPRHH", 2)),
                    PYSCRIPT=build_tools.File('cxx_config_hh.py'),
                    MODULE=module,
                    CXXCONFIG_HH=build_dir.File(f'cxx_config/{simobj}.hh'))

            # CXX config cc.
            cc_file=build_dir.File(f'cxx_config/{simobj}.cc')
            gem5py_env.Command([ "${CXXCONFIG_CC}" ], srcs,
                    MakeAction(cmdline('CXXCONFIG_CC'),
                        Transform("CXXCPRCC", 2)),
                    PYSCRIPT=build_tools.File('cxx_config_cc.py'),
                    MODULE=module,
                    CXXCONFIG_CC=cc_file)
            if GetOption('with_cxx_config'):
                Source(cc_file, tags=self.tags)

        # C++ versions of enum params.
        for enum in enums:
            gem5py_env.Command([ "${ENUM_HH}" ],
                    [ Value(module), Value(enum),
                        "${GEM5PY_M5}", "${ENUMHH_PY}" ],
                    MakeAction('"${GEM5PY_M5}" "${ENUMHH_PY}" "${MODULE}" ' \
                            '"${ENUM_HH}"',
                        Transform("ENUMDECL", 2)),
                    MODULE=module,
                    ENUM=enum,
                    ENUM_HH=build_dir.File(f'enums/{enum}.hh'),
                    ENUMHH_PY=build_tools.File('enum_hh.py'))
            cc_file = build_dir.File(f'enums/{enum}.cc')
            gem5py_env.Command([ "${ENUM_CC}" ],
                    [ Value(module), Value(enum),
                        "${GEM5PY_M5}", "${ENUMCC_PY}" ],
                    MakeAction('"${GEM5PY_M5}" "${ENUMCC_PY}" "${MODULE}" ' \
                            '"${ENUM_CC}" "${USE_PYTHON}"',
                        Transform("ENUM STR", 2)),
                    MODULE=module,
                    ENUM=enum,
                    ENUM_CC=cc_file,
                    ENUMCC_PY=build_tools.File('enum_cc.py'),
                    USE_PYTHON='--use-python' if env['USE_PYTHON'] else '')
            Source(cc_file, tags=self.tags, add_tags='python')

# This regular expression is simplistic and assumes that the import takes up
# the entire line, doesn't have the keyword "public", uses double quotes, has
# no whitespace at the end before or after the ;, and is all on one line. This
# should still cover most cases, and a completely accurate scanner would be
# MUCH more complex.
protoc_scanner = SCons.Scanner.Classic(name='ProtobufScanner',
                                       suffixes=['.proto'],
                                       path_variable='BUILDDIR',
                                       regex=r'^import\s+\"(.*\.proto)\"\;$')
env.Append(SCANNERS=protoc_scanner)

def protoc_emitter(target, source, env):
    root, ext = os.path.splitext(source[0].get_abspath())
    return [root + '.pb.cc', root + '.pb.h'], source

protoc_action = MakeAction('${PROTOC} --cpp_out ${BUILDDIR} '
        '--proto_path ${BUILDDIR} --proto_path ${SOURCE.dir} '
        '${SOURCE.get_abspath()}',
        Transform("PROTOC"))
protobuf_builder = Builder(action=protoc_action, emitter=protoc_emitter,
        src_suffix='.proto')
env.Append(BUILDERS={'ProtoBufCC' : protobuf_builder})

c_file, cxx_file = SCons.Tool.createCFileBuilders(env)
cxx_file.add_action('.proto', protoc_action)
cxx_file.add_emitter('.proto', protoc_emitter)

def ProtoBuf(source, tags=None, add_tags=None):
    '''Add a Protocol Buffer to build'''

    if not env['HAVE_PROTOC'] or not env['HAVE_PROTOBUF']:
        error('Got protobuf to build, but lacks support!')

    '''Specify the source file, and any tags'''
    Source(source, tags, add_tags, append={'CXXFLAGS': '-Wno-array-bounds'})

env['PROTOC_GRPC'] = distutils.spawn.find_executable('grpc_cpp_plugin')
if env['PROTOC_GRPC']:
    env.Append(LIBS=['grpc++'])

def protoc_grpc_emitter(target, source, env):
    root, ext = os.path.splitext(source[0].get_abspath())
    return [root + '.grpc.pb.cc', root + '.grpc.pb.h'], source

protoc_grpc_action=MakeAction('${PROTOC} --grpc_out ${BUILDDIR} '
        '--plugin=protoc-gen-grpc=${PROTOC_GRPC} --proto_path ${BUILDDIR} '
        '${SOURCE.get_abspath()}',
        Transform("PROTOC"))

env.Append(BUILDERS={'GrpcProtoBufCC' : Builder(
            action=protoc_grpc_action,
            emitter=protoc_grpc_emitter
        )})

def GrpcProtoBuf(source, tags=None, add_tags=None):
    '''Add a GRPC protocol buffer to the build'''

    if not env['PROTOC_GRPC']:
        error('No grpc_cpp_plugin found')

    Source(env.GrpcProtoBufCC(source=source)[0], tags=tags, add_tags=add_tags)
    Source(env.ProtoBufCC(source=source)[0], tags=tags, add_tags=add_tags)



date_source = File('base/date.cc')

class TopLevelMeta(type):
    '''Meta class for top level build products, ie binaries and libraries.'''
    all = []

    def __init__(cls, name, bases, d):
        TopLevelMeta.all.append(cls)
        super().__init__(name, bases, d)
        cls.all = []

class TopLevelBase(object, metaclass=TopLevelMeta):
    '''Base class for linked build products.'''

    def __init__(self, target, *srcs_and_filts):
        '''Specify the target name and any sources. Sources that are
        not SourceFiles are evalued with Source().'''
        super().__init__()
        self.all.append(self)
        self.target = target

        isFilter = lambda arg: isinstance(arg, SourceFilter)
        isLib = lambda arg: isinstance(arg, SourceLib)
        # If something isn't a library or filter, assume it's a source file.
        isSourceFile = lambda arg: not isFilter(arg) and not isLib(arg)
        self.filters = list(filter(isFilter, srcs_and_filts))
        self.sourceLibs = list(filter(isLib, srcs_and_filts))
        source_files = list(filter(isSourceFile, srcs_and_filts))

        srcs = SourceList()
        for src in source_files:
            if not isinstance(src, SourceFile):
                src = Source(src, tags=[])
            srcs.append(src)
        self.srcs = srcs

        self.dir = Dir('.')

    def sources(self, env):
        srcs = self.srcs
        for f in self.filters:
            srcs += Source.all.apply_filter(env, f)
        return srcs

    def libs(self, env):
        libs = self.sourceLibs
        for f in self.filters:
            libs += SourceLib.all.apply_filter(env, f)
        return libs

    def srcs_to_objs(self, env, sources):
        return list([ s.static(env) for s in sources ])

    @classmethod
    def declare_all(cls, env):
        return list([ instance.declare(env) for instance in cls.all ])

class StaticLib(TopLevelBase):
    '''Base class for creating a static library from sources.'''

    def declare(self, env):
        objs = self.srcs_to_objs(env, self.sources(env))

        date_obj = env.StaticObject(date_source)
        env.Depends(date_obj, objs)

        return env.StaticLibrary(self.target, [date_obj, objs])[0]

class SharedLib(TopLevelBase):
    '''Base class for creating a shared library from sources.'''

    def srcs_to_objs(self, env, sources):
        return list([ s.shared(env) for s in sources ])

    def declare(self, env):
        objs = self.srcs_to_objs(env, self.sources(env))

        date_obj = env.SharedObject(date_source)
        env.Depends(date_obj, objs)

        return env.SharedLibrary(self.target, [date_obj, objs])[0]

class Executable(TopLevelBase):
    '''Base class for creating an executable from sources.'''

    def path(self, env):
        return self.dir.File(self.target + '.${ENV_LABEL}')

    def declare(self, env, objs=None):
        if objs is None:
            objs = self.srcs_to_objs(env, self.sources(env))

        env = env.Clone()
        env['BIN_RPATH_PREFIX'] = os.path.relpath(
                env['BUILDDIR'], self.path(env).dir.abspath)

        libs = self.libs(env)
        if libs:
            env.Append(LIBS=list(lib.source for lib in libs))

        executable = env.Program(self.path(env).abspath, objs)[0]

        if sys.platform == 'sunos5':
            cmd = 'cp $SOURCE $TARGET; strip $TARGET'
        else:
            cmd = 'strip $SOURCE -o $TARGET'
        stripped = env.Command(str(executable) + '.stripped',
                executable, MakeAction(cmd, Transform("STRIP")))[0]

        return [executable, stripped]

class Gem5(Executable):
    '''Base class for the main gem5 executable.'''

    def declare(self, env):
        objs = self.srcs_to_objs(env, self.sources(env))

        date_obj = env.StaticObject(date_source)
        env.Depends(date_obj, objs)
        objs.append(date_obj)

        return super().declare(env, objs)


class GTest(Executable):
    '''Create a unit test based on the google test framework.'''
    all = []
    def __init__(self, *srcs_and_filts, **kwargs):
        if not kwargs.pop('skip_lib', False):
            srcs_and_filts = srcs_and_filts + (with_tag('gtest lib'),)
        super().__init__(*srcs_and_filts)

    @classmethod
    def declare_all(cls, env):
        env = env.Clone()
        env['OBJSUFFIX'] = '.t' + env['OBJSUFFIX'][1:]
        env['SHOBJSUFFIX'] = '.t' + env['SHOBJSUFFIX'][1:]
        env.Append(LIBS=env['GTEST_LIBS'])
        env.Append(CPPFLAGS=env['GTEST_CPPFLAGS'])
        env['GTEST_OUT_DIR'] = \
            Dir(env['BUILDDIR']).Dir('unittests.${ENV_LABEL}')
        return super().declare_all(env)

    def declare(self, env):
        binary, stripped = super().declare(env)

        out_dir = env['GTEST_OUT_DIR']
        xml_file = out_dir.Dir(str(self.dir)).File(self.target + '.xml')
        AlwaysBuild(env.Command(xml_file.abspath, binary,
            "${SOURCES[0]} --gtest_output=xml:${TARGETS[0]}"))

        return binary


# Children should have access
Export('GdbXml')
Export('Source')
Export('SourceLib')
Export('PySource')
Export('SimObject')
Export('ProtoBuf')
Export('GrpcProtoBuf')
Export('Executable')
Export('GTest')

########################################################################
#
# Debug Flags
#

debug_flags = set()
def DebugFlagCommon(name, flags, desc, fmt, tags, add_tags):
    if name == "All":
        raise AttributeError('The "All" flag name is reserved')
    if name in debug_flags:
        raise AttributeError(f'Flag {name} already specified')

    debug_flags.add(name)

    hh_file = Dir(env['BUILDDIR']).Dir('debug').File(f'{name}.hh')
    gem5py_env.Command(hh_file,
        [ '${GEM5PY}', '${DEBUGFLAGHH_PY}' ],
        MakeAction('"${GEM5PY}" "${DEBUGFLAGHH_PY}" "${TARGET}" "${NAME}" ' \
                   '"${DESC}" "${FMT}" "${COMPONENTS}"',
        Transform("TRACING", 0)),
        DEBUGFLAGHH_PY=build_tools.File('debugflaghh.py'),
        NAME=name, DESC=desc, FMT=('True' if fmt else 'False'),
        COMPONENTS=':'.join(flags))
    cc_file = Dir(env['BUILDDIR']).Dir('debug').File('%s.cc' % name)
    gem5py_env.Command(cc_file,
            [ "${GEM5PY}", "${DEBUGFLAGCC_PY}" ],
            MakeAction('"${GEM5PY}" "${DEBUGFLAGCC_PY}" "${TARGET}" "${NAME}"',
                Transform("TRACING", 0)),
            DEBUGFLAGCC_PY=build_tools.File('debugflagcc.py'), NAME=name)
    if not add_tags:
        add_tags = set()
    if isinstance(add_tags, str):
        add_tags = { add_tags }
    if not isinstance(add_tags, set):
        add_tags = set(add_tags)
    add_tags.add('gem5 trace')
    Source(cc_file, tags=tags, add_tags=add_tags)

def DebugFlag(name, desc=None, fmt=False, tags=None, add_tags=None):
    DebugFlagCommon(name, (), desc, fmt, tags=tags, add_tags=add_tags)
def CompoundFlag(name, flags, desc=None, tags=None, add_tags=None):
    DebugFlagCommon(name, flags, desc, False, tags=tags, add_tags=add_tags)
def DebugFormatFlag(name, desc=None, tags=None, add_tags=None):
    DebugFlag(name, desc, True, tags=tags, add_tags=add_tags)

Export('DebugFlag')
Export('CompoundFlag')
Export('DebugFormatFlag')

########################################################################
#
# Set some compiler variables
#

# Include file paths are rooted in this directory.  SCons will
# automatically expand '.' to refer to both the source directory and
# the corresponding build directory to pick up generated include
# files.
env.Append(CPPPATH=Dir('.'))

for extra_dir in extras_dir_list:
    env.Append(CPPPATH=Dir(extra_dir))

########################################################################
#
# Walk the tree and execute all SConscripts in subdirectories
#

here = Dir('.').srcnode().abspath
for root, dirs, files in os.walk(base_dir, topdown=True):
    if root == here:
        # we don't want to recurse back into this SConscript
        continue

    if 'SConscript' in files:
        build_dir = os.path.join(env['BUILDDIR'], root[len(base_dir) + 1:])
        SConscript(os.path.join(root, 'SConscript'), variant_dir=build_dir)

for extra_dir in extras_dir_list:
    prefix_len = len(os.path.dirname(extra_dir)) + 1

    # Also add the corresponding build directory to pick up generated
    # include files.
    env.Append(CPPPATH=Dir(env['BUILDDIR']).Dir(extra_dir[prefix_len:]))

    for root, dirs, files in os.walk(extra_dir, topdown=True):
        # if build lives in the extras directory, don't walk down it
        if 'build' in dirs:
            dirs.remove('build')

        if 'SConscript' in files:
            build_dir = os.path.join(env['BUILDDIR'], root[prefix_len:])
            SConscript(os.path.join(root, 'SConscript'), variant_dir=build_dir)

for opt in all_export_vars:
    env.ConfigFile(opt)

def makeTheISA(source, target, env):
    isas = sorted(set(env.Split('${ALL_ISAS}')))
    target_isa = env['TARGET_ISA']
    is_null_isa = '1' if (target_isa.lower() == 'null') else '0'

    def namespace(isa):
        return isa[0].upper() + isa[1:].lower() + 'ISA'


    code = code_formatter()
    code('''\
#ifndef __CONFIG_THE_ISA_HH__
#define __CONFIG_THE_ISA_HH__

#define IS_NULL_ISA ${{is_null_isa}}
#define TheISA ${{namespace(target_isa)}}

#endif // __CONFIG_THE_ISA_HH__''')

    code.write(str(target[0]))

env.Command('config/the_isa.hh', [],
            MakeAction(makeTheISA, Transform("CFG ISA", 0)))

def makeTheGPUISA(source, target, env):
    gpu_isa = env['TARGET_GPU_ISA']

    if gpu_isa:
        namespace = gpu_isa[0].upper() + gpu_isa[1:].lower() + 'ISA'
    else:
        namespace = 'None'

    code = code_formatter()
    code('''\
#ifndef TheGpuISA
#define TheGpuISA ${namespace}
#endif // TheGpuISA''')

    code.write(str(target[0]))

env.Command('config/the_gpu_isa.hh', [],
            MakeAction(makeTheGPUISA, Transform("CFG ISA", 0)))


########################################################################
#
# Commands for the basic automatically generated python files
#

# Generate Python file containing a dict specifying the current
# buildEnv flags.
def makeDefinesPyFile(target, source, env):
    code = code_formatter()
    code("buildEnv = $0", FromValue(source[0]))
    code.write(target[0].abspath)

# Generate a file with all of the compile options in it
env.Command('python/m5/defines.py', ToValue(dict(build_env)),
            MakeAction(makeDefinesPyFile, Transform("DEFINES", 0)))
PySource('m5', 'python/m5/defines.py')

# Generate a file that wraps the basic top level files
gem5py_env.Command('python/m5/info.py',
            [ File('#/COPYING'), File('#/LICENSE'), File('#/README'),
                "${GEM5PY}", "${INFOPY_PY}" ],
            MakeAction('"${GEM5PY}" "${INFOPY_PY}" "${TARGET}" '
                       '${SOURCES[:-2]}',
                Transform("INFO", 3)),
            INFOPY_PY=build_tools.File('infopy.py'))
PySource('m5', 'python/m5/info.py')

gem5py_m5_env = gem5py_env.Clone()
gem5py_env.Append(CPPPATH=env['CPPPATH'])
gem5py_env.Append(LIBS='z')
gem5py_env.Program(gem5py, 'python/gem5py.cc')[0]
m5_module_source = \
        Source.all.with_all_tags(env, 'm5_module', 'gem5 lib')
m5_module_static = list(map(lambda s: s.static(gem5py_env), m5_module_source))
gem5py_env.Program(gem5py_m5, [ 'python/gem5py.cc' ] + m5_module_static)


# version tags
tags = \
env.Command('sim/tags.cc', None,
            MakeAction('util/cpt_upgrader.py --get-cc-file > $TARGET',
                       Transform("VER TAGS")))
env.AlwaysBuild(tags)

########################################################################
#
# Define binaries.  Each different build type (debug, opt, etc.) gets
# a slightly different build environment.
#

env['SHOBJSUFFIX'] = '${OBJSUFFIX}s'

envs = {
    'debug': env.Clone(ENV_LABEL='debug', OBJSUFFIX='.do'),
    'opt': env.Clone(ENV_LABEL='opt', OBJSUFFIX='.o'),
    'fast': env.Clone(ENV_LABEL='fast', OBJSUFFIX='.fo'),
}

envs['debug'].Append(CPPDEFINES=['DEBUG', 'TRACING_ON=1'])
envs['opt'].Append(CCFLAGS=['-g'], CPPDEFINES=['TRACING_ON=1'])
envs['fast'].Append(CPPDEFINES=['NDEBUG', 'TRACING_ON=0'])

# For Link Time Optimization, the optimisation flags used to compile
# individual files are decoupled from those used at link time
# (i.e. you can compile with -O3 and perform LTO with -O0), so we need
# to also update the linker flags based on the target.
if env['GCC']:
    if sys.platform == 'sunos5':
        envs['debug'].Append(CCFLAGS=['-gstabs+'])
    else:
        envs['debug'].Append(CCFLAGS=['-ggdb3'])
    envs['debug'].Append(LINKFLAGS=['-O0'])
    # opt and fast share the same cc flags, also add the optimization to the
    # linkflags as LTO defers the optimization to link time
    for target in ['opt', 'fast']:
        envs[target].Append(CCFLAGS=['-O3', '${LTO_CCFLAGS}'])
        envs[target].Append(LINKFLAGS=['-O3', '${LTO_LINKFLAGS}'])

elif env['CLANG']:
    envs['debug'].Append(CCFLAGS=['-g', '-O0'])
    # opt and fast share the same cc flags
    for target in ['opt', 'fast']:
        envs[target].Append(CCFLAGS=['-O3'])
else:
    error('Unknown compiler, please fix compiler options')


# To speed things up, we only instantiate the build environments we need. We
# try to identify the needed environment for each target; if we can't, we fall
# back on instantiating all the environments just to be safe.

# A set of all the extensions on targets.
target_exts = set({ os.path.splitext(t)[1] for t in BUILD_TARGETS })
needed_envs = set()
for ext in target_exts:
    match = next((e for e in envs.values() if ext in (
                    '.' + e['ENV_LABEL'], e['OBJSUFFIX'])), None)
    if match:
        needed_envs.add(match['ENV_LABEL'])
    else:
        needed_envs |= set(envs.keys())
        break


# SCons doesn't know to append a library suffix when there is a '.' in the
# name. Use '_' instead.
lib_name = 'gem5_${ENV_LABEL}'

lib_filter = with_tag('gem5 lib')

# Without Python, leave out all Python content from the library builds. The
# option doesn't affect gem5 built as a program.
if GetOption('without_python'):
    lib_filter = lib_filter & without_tag('python')

StaticLib(lib_name, lib_filter)
SharedLib(lib_name, lib_filter)

Gem5('gem5', with_any_tags('gem5 lib', 'main'))


# Function to create a new build environment as clone of current
# environment 'env' with modified object suffix and optional stripped
# binary.
for env in (envs[e] for e in needed_envs):
    for cls in TopLevelMeta.all:
        cls.declare_all(env)