You can generate an Eclipse project by running:

./mach ide eclipse

See also the Eclipse CDT docs on MDN.

Visual Studio

You can run a Visual Studio project by running:

./mach ide visualstudio

CompileDB back-end / compileflags

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 VIM integration works, for example.