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mongodb/site_scons/site_tools/ccache.py

99 lines
3.2 KiB
Python

# Copyright 2019 MongoDB Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import math
import os
import re
import subprocess
import SCons
from pkg_resources import parse_version
# This is the oldest version of ccache that offers support for -gsplit-dwarf
_ccache_version_min = parse_version('3.2.3')
_ccache_version_found = None
def exists(env):
"""Look for a viable ccache implementation that meets our version requirements."""
# If we already generated, we definitely exist
if 'CCACHE_VERSION' in env:
return True
ccache = env.get('CCACHE', False)
if not ccache:
return False
ccache = env.WhereIs(ccache)
if not ccache:
return False
pipe = SCons.Action._subproc(env,
SCons.Util.CLVar(ccache) + ['--version'], stdin='devnull',
stderr='devnull', stdout=subprocess.PIPE)
if pipe.wait() != 0:
return False
validated = False
for line in pipe.stdout:
line = line.decode('utf-8')
if validated:
continue # consume all data
version_banner = re.search(r'^ccache version', line)
if not version_banner:
continue
ccache_version = re.split('ccache version (.+)', line)
if len(ccache_version) < 2:
continue
global _ccache_version_found
_ccache_version_found = parse_version(ccache_version[1])
if _ccache_version_found >= _ccache_version_min:
validated = True
return validated
def generate(env):
"""Add ccache support."""
# If we have already generated the tool, don't generate it again.
if 'CCACHE_VERSION' in env:
return
# If we can't find ccache, or it is too old a version, don't
# generate.
if not exists(env):
return
# Record our found CCACHE_VERSION. Other tools that need to know
# about ccache (like iecc) should query this variable to determine
# if ccache is active. Looking at the CCACHE variable in the
# environment is not sufficient, since the user may have set it,
# but it doesn't work or is out of date.
env['CCACHE_VERSION'] = _ccache_version_found
# ccache does not support response files so force scons to always
# use the full command
#
# Note: This only works for Python versions >= 3.5
env['MAXLINELENGTH'] = math.inf
# Add ccache to the relevant command lines. Wrap the reference to
# ccache in the $( $) pattern so that turning ccache on or off
# doesn't invalidate your build.
env['CCCOM'] = '$( $CCACHE $)' + env['CCCOM']
env['CXXCOM'] = '$( $CCACHE $)' + env['CXXCOM']
env['SHCCCOM'] = '$( $CCACHE $)' + env['SHCCCOM']
env['SHCXXCOM'] = '$( $CCACHE $)' + env['SHCXXCOM']