Testing removal of ifdef or configure checks: Difference between revisions
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=#ifdef removal is risky= |
=#ifdef removal is risky= |
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Large-scale removal of "unused" ifdef is an important, but risky task. |
Large-scale removal of "unused" ifdef or the configure checks that produce #defines is an important, but risky task. |
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It is difficult (and time consuming) to prove that the code is unused and that there is no change to the compiled output. |
It is difficult (and time consuming) to prove that the code is unused and that there is no change to the compiled output. |
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==A script to help== |
==A script to help== |
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[[File:Gcc-E.py.txt]] is a Python script that wraps gcc -E to attempt to solve this dilemma, so as to provide a result that can be reasoned with via tools like [https://www.samba.org/ftp/paulus/ dirdiff] |
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===Getting the results=== |
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git checkout origin/master |
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git clean -x -f -d |
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CC="gcc -E" ./configure.developer && make -j |
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mv bin /tmp/master-bin |
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git checkout newbranch |
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git clean -x -f -d |
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CC="gcc -E" ./configure.developer && make -j |
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===Reading the results=== |
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dirdiff /tmp/master-bin bin |
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or |
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diff -ur --ignore-matching-lines="^#" /tmp/master-bin/ bin> /tmp/diff |
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Revision as of 02:30, 27 April 2019
#ifdef removal is risky
Large-scale removal of "unused" ifdef or the configure checks that produce #defines is an important, but risky task.
It is difficult (and time consuming) to prove that the code is unused and that there is no change to the compiled output.
A script to help
File:Gcc-E.py.txt is a Python script that wraps gcc -E to attempt to solve this dilemma, so as to provide a result that can be reasoned with via tools like dirdiff
Getting the results
git checkout origin/master git clean -x -f -d CC="gcc -E" ./configure.developer && make -j mv bin /tmp/master-bin git checkout newbranch git clean -x -f -d CC="gcc -E" ./configure.developer && make -j
Reading the results
dirdiff /tmp/master-bin bin
or
diff -ur --ignore-matching-lines="^#" /tmp/master-bin/ bin> /tmp/diff