Many modern C++ development tools in the clang/LLVM toolchain, such as clang-tidy or clangd, rely on the presence of a compilation database in JSON format. This package temporarily injects additional build flags into the R build process to generate such a compilation database.
A full package build including compilation is necessary to generate the compilation database.
This package is purely meant for platforms that support R built with clang, which essentially excludes Windows. Rtools is built around GCC and I am not aware of clang being used within the R world on Windows.
Currently, this method only works for packages utilizing the
standard R build process, i.e. the only modifications to the build
process come in the form of Makevars, or the configurable
variant Makevars.in, in the package’s src
directory. This supports a broad range of packages since it allows for
custom configure files as long as they do not create a
Makevars file from scratch but rather modify a
Makevars.in.
For packages using their own custom Makefiles,
additional effort from the package authors side may be necessary to
generate the compilation database(s).
You can install the development version of compdb like so:
remotes::install_github("cyianor/r-compdb")Using this package is simple and only requires a call to
build_compile_commands(path = ".")where path should point to the packages base path. It
will produce a file called compile_commands.json in the
package’s src/ directory.
The package at path is built as a source package to a
temporary location. If the package already contains a
Makevars file, it is modified at the temporary location to
include PKG_CPPFLAGS += -MJ \@.json which will prompt
clang to generate a compilation database for each file it
processes. If no Makevars file exists, a new one is
created. The package is then installed to a temporary location which
triggers compilation of all source files and thereby generates the
compilation databases.
Finally, the compilation databases are merged and the directory of each file in the compilation database is corrected from the temporary directory to the actual package directory.
This package is essentially a re-implementation of the bash script at ashiklom/rcpp-cmpdb with additional bells and whistles.