Clang tidy lints for Lix
This is a skeleton of a clang-tidy lints library for Lix.
Currently there is one check (which is already obsolete as it has served its
goal and is there as an example), HasPrefixSuffixCheck.
Running fixes/checks
One file:
ninja -C build && clang-tidy --checks='-*,lix-*' --load=build/liblix-clang-tidy.so -p ../../build -header-filter '\.\./lix/.*\.h' --fix ../../lix/libcmd/installables.cc
Several files, in parallel:
ninja -C build && run-clang-tidy -checks='-*,lix-*' -load=build/liblix-clang-tidy.so -p ../../build -header-filter '\.\./lix/.*\.h' -fix ../../lix | tee -a clang-tidy-result
Resources
- https://firefox-source-docs.mozilla.org/code-quality/static-analysis/writing-new/clang-query.html
- https://clang.llvm.org/docs/LibASTMatchersReference.html
- https://devblogs.microsoft.com/cppblog/exploring-clang-tooling-part-3-rewriting-code-with-clang-tidy/
Developing new checks
Put something like so in myquery.txt:
set traversal IgnoreUnlessSpelledInSource
# ^ Ignore implicit AST nodes. May need to use AsIs depending on how you are
# working.
set bind-root true
# ^ true unless you use any .bind("foo") commands
set print-matcher true
enable output dump
match callExpr(callee(functionDecl(hasName("hasPrefix"))), optionally(hasArgument( 0, cxxConstructExpr(hasDeclaration(functionDecl(hasParameter(0, parmVarDecl(hasType(asString("const char *"))).bind("meow2"))))))))
Then run, e.g. clang-query --preload hasprefix.query -p compile_commands.json lix/libcmd/installables.cc.
With this you can iterate a query before writing it in C++ and suffering from C++.
Tips and tricks for the C++
There is a function dump() on many things that will dump to stderr. Also
llvm::errs() lets you print to stderr.
When I wrote HasPrefixSuffixCheck, I was not really able to figure out how
the structured replacement system was supposed to work. In principle you can
describe the replacement with a nice DSL. Look up the Stencil system in Clang
for details.