43b026f3f9
The GEM5_DEPRECATED_NAMESPACE macro temporarily declares a namespace with the deprecated name that prints a warning message when used. It also make sure that when the old namespace name is used the new name is referenced. The GEM5_DEPRECATED_CLASS macro deprecates classes that were renamed, or moved to different namespaces. Attributes in namespaces are an issue, though. - Clang only allows from version 6 on, and only when using C++17. - GCC has a bug before version 10 where the deprecated attribute was not properly recognized in namespaces: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79817 Possible solutions for GCC < 10: 1) \#define GEM5_DEPRECATED_NAMESPACE() \ namespace gem5 { namespace deprecated { \ auto namespace_##old_namespace = [](){ \ GEM5_DEPRECATED("Please use the new namespace: '" \ \#new_namespace "'") \ int old_namespace; \ return old_namespace; \ }; \ }} \ namespace new_namespace {} \ namespace old_namespace { \ using namespace new_namespace; \ } Add the above macro to all headers that previously declared the deprecated namespace to trigger a warning. This is extremely inconvenient because every file that includes that header will trigger the deprecation warning, so the compilation output gets VERY clogged. 2) Similar to 1), but do not use the temporary variable on declaration. This would require using the variable somewhere else, like a respective .c file. This is not always possible, so we could resort to adding a special file (e.g., base/deprecated_elements.cc) containing all uses of the deprecated temporary variables. 3) \#define GEM5_DEPRECATED_NAMESPACE(old_ns, new_ns) \ namespace old_ns = new_ns; Similar to 3), but simply declare an alias in the header files (see above macro) to maintain backwards compatibility. Then use the special file to declare all deprecation messages. 4) Rely on release notes / e-mail to the mailing list to inform that those are deprecated. We have selected option 4 for these problematic instances. Checking if namespace deprecation is possible is done through scons. Jira issues: https://gem5.atlassian.net/browse/GEM5-975 https://gem5.atlassian.net/browse/GEM5-991 Change-Id: Ide234f6a8707d88a869fa843bf8c61ca7714e4f3 Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br> Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/45246 Reviewed-by: Jason Lowe-Power <power.jg@gmail.com> Maintainer: Jason Lowe-Power <power.jg@gmail.com> Tested-by: kokoro <noreply+kokoro@google.com>
76 lines
3.3 KiB
Plaintext
76 lines
3.3 KiB
Plaintext
# Copyright 2020 Google, Inc.
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#
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# Redistribution and use in source and binary forms, with or without
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# modification, are permitted provided that the following conditions are
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# met: redistributions of source code must retain the above copyright
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# notice, this list of conditions and the following disclaimer;
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# redistributions in binary form must reproduce the above copyright
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# notice, this list of conditions and the following disclaimer in the
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# documentation and/or other materials provided with the distribution;
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# neither the name of the copyright holders nor the names of its
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# contributors may be used to endorse or promote products derived from
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# this software without specific prior written permission.
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#
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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Import('*')
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from gem5_scons import warning
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import gem5_scons
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with gem5_scons.Configure(main) as conf:
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# Check for <fenv.h> (C99 FP environment control)
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conf.env['HAVE_FENV'] = conf.CheckHeader('fenv.h', '<>')
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if not conf.env['HAVE_FENV']:
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warning("Header file <fenv.h> not found.\n"
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"This host has no IEEE FP rounding mode control.")
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# Check for <png.h> (libpng library needed if wanting to dump
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# frame buffer image in png format)
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conf.env['HAVE_PNG'] = conf.CheckHeader('png.h', '<>')
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if not conf.env['HAVE_PNG']:
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warning("Header file <png.h> not found.\n"
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"This host has no libpng library.\n"
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"Disabling support for PNG framebuffers.")
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have_posix_clock = \
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conf.CheckLibWithHeader([None, 'rt'], 'time.h', 'C',
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'clock_nanosleep(0,0,NULL,NULL);')
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if not have_posix_clock:
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warning("Can't find library for POSIX clocks.")
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# Valgrind gets much less confused if you tell it when you're using
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# alternative stacks.
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conf.env['HAVE_VALGRIND'] = conf.CheckCHeader('valgrind/valgrind.h')
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conf.env['HAVE_DEPRECATED_NAMESPACE'] = conf.TryCompile('''
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int main() {return 0;}
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namespace [[gnu::deprecated("Test namespace deprecation")]]
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test_deprecated_namespace {}
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''', '.cc')
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if not conf.env['HAVE_DEPRECATED_NAMESPACE']:
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warning("Deprecated namespaces are not supported by this compiler.\n"
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"Please make sure to check the mailing list for deprecation "
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"announcements.")
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sticky_vars.Add(BoolVariable('USE_POSIX_CLOCK', 'Use POSIX Clocks',
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have_posix_clock))
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export_vars.extend([
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'HAVE_FENV', 'HAVE_PNG', 'USE_POSIX_CLOCK', 'HAVE_VALGRIND',
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'HAVE_DEPRECATED_NAMESPACE'])
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