Does xcode 7compiles all files upon build action

Question

1. Do xcode 7 compiles all files upon build action while only few files are modified?
2. If YES, does XcodeBuild provides any support to customize building process by compiling only modified files ?

Thanks

Answer 1

1. No. Xcode, by default, will not recompile unchanged files.
2. You can force a recompile of all files in the target, by first issuing a "clean" command.
3. Also note that Xcode will only compile files which are members of the current target.

Answer 2

No, Xcode tracks dependencies and only compiles those files that need to be recompiled. If you're working in Objective-C it's a good idea to put your #import statements in your .m files where possible, since it prevents your project from becoming dependent on every single header file. (I don't know as much about how dependencies are determined in Swift.)