This is a clang/libTooling based refactoring tool meant to serve as an example of project specific, custom taylored tooling.
It finds usages of std::pow with static integer exponents and replaces them by
calls to a templated utils::pow<> that is expected to exist inside the user code.
Note: std::pow usually involves a function call, which can be a bottle-neck in
very performance critical code paths. With an inline, templated power function
made for integer potentation, this overhead can be reduced to O(log(exponent))
multiplications. On most common platforms, though, compilers support the flag
-ffast-math, which among other optimizations applies this same optimization to
std::pow directly.
In order to find all clang system headers properly, this tool needs to be installed
to the same location, as clang is. The install location is specified as a command
line argument to cmake with -DCMAKE_INSTALL_PREFIX=/path/.
cd path/to/kdab-supercede-stdpow-checker
mkdir build && cd build
cmake -GNinja -DCMAKE_INSTALL_PREFIX=/usr ..
ninja
sudo ninja install
or, if you prefer to use make
cd path/to/kdab-supercede-stdpow-checker
mkdir build && cd build
cmake -DCMAKE_INSTALL_PREFIX=/usr ..
make -j
sudo make install
The easiest way to use this tool is with a compilation database. If you use
cmake for configuring your project, you can create one by passing
-DCMAKE_EXPORT_COMPILE_COMMANDS=ON to cmake as command line argument. Then,
you can analyze a source file using
kdab-supercede-stdpow-checker -p /path/to/build/dir /path/to/sourcefile.cpp
Alternatively or additionally, you may pass compiler arguments and flags to
kdab-supercede-stdpow-checker after a double dash.
kdab-supercede-stdpow-checker /path/to/sourcefile.cpp -- -std=c++17 -I/usr/include/qt/QtCore
For additional information on how to create libtooling based custom tooling, see https://clang.llvm.org/docs/LibTooling.html https://clang.llvm.org/docs/LibASTMatchersReference.html https://clang.llvm.org/docs/InternalsManual.html