You can generate an Eclipse project by running:
./mach ide eclipse
See also the Eclipse CDT docs on MDN.
You can run a Visual Studio project by running:
./mach ide visualstudio
You can generate a compile_commands.json in your object directory by
running:
./mach build-backend --backend=CompileDB
This file, the compilation database, is understood by a variety of C++ editors / IDEs to provide auto-completion capabilities. You can also get an individual compile command by running:
./mach compileflags path/to/file
This is how the :ref:`VIM <VIM>` integration works, for example.