clang-cl
clang-cl is the command line tool in Visual Studio capable of invoking the clang compiler with the arguments of msvc. In Visual Studio projects one can just flip the toolset and the clang compiler will be chosen. clang has the following positive aspects:
- better C++ conformance. Examples are that msvc is leniant towards missing 'typename' for dependent types and 'template' for nesting templates; clang picks them up. There are other issues.
- offers some code improvements like correct member order in constructors and virtuals which override base class
- detects some performance improvements like advising to use shared_ptr by reference in loops
- more precise compilation warnings and errors
It has also some drawbacks:
- some noisy warnings
- does not understand all msvc code. For example the msvc's #import extension is not understood
Despite using msvc's code analysis the clang compiler was still able to pick up other issues. Some clang warnings are far fetched and one can choose to disable them. This is especially needed for external libraries which one cannot easily patch. To disable warnings one can use the following:
#ifdef __clang__
#pragma clang diagnostic ignored "-Wimplicit-exception-spec-mismatch"
#pragma clang diagnostic ignored "-Wmissing-field-initializers"
#pragma clang diagnostic ignored "-W#pragma-messages"
#pragma clang diagnostic ignored "-Wunused-but-set-variable"
#pragma clang diagnostic ignored "-Wunused-local-typedef"
#endif
The first one for example is necessary to suppress warnings in MFC. 'delete' should be specified with 'noexcept' but the MFC delete lacks this.
