mongodb/site_scons/site_tools/incremental_link.py

# Copyright 2017 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 SCons


def _tag_as_precious(target, source, env):
    env.Precious(target)
    return target, source


def generate(env):
    builders = env["BUILDERS"]
    for builder in ("Program", "SharedLibrary", "LoadableModule"):
        emitter = builders[builder].emitter
        builders[builder].emitter = SCons.Builder.ListEmitter(
            [emitter, _tag_as_precious,]
        )


def exists(env):
    # By default, the windows linker is incremental, so unless
    # overridden in the environment with /INCREMENTAL:NO, the tool is
    # in play.
    if env.TargetOSIs("windows") and not "/INCREMENTAL:NO" in env["LINKFLAGS"]:
        return True

    # On posix platforms, excluding darwin, we may have enabled
    # incremental linking. Check for the relevant flags.
    if (
        env.TargetOSIs("posix")
        and not env.TargetOSIs("darwin")
        and "-fuse-ld=gold" in env["LINKFLAGS"]
        and "-Wl,--incremental" in env["LINKFLAGS"]
    ):
        return True

    return False