3bdbf74d47
This adds support for dropping cleanups for temporary values when they are moved somewhere else. It then adds wraps most copy operations (return, put in data structure, box, etc) in a way that will fall back to a move when it is safe. This saves a lot of taking/dropping, shaving over a megabyte off the stage2/rustc binary size. In some cases, most notably function returns, we could detect that the returned value is a local variable, and can thus be safely moved even though it is not a temporary. This will require putting some more information in lvals. I did not yet handle function arguments, since the logic for passing them looked too convoluted to touch. I'll probably try that in the near future, since it's bound to be a big win.
This is a compiler and suite of associated libraries and documentation for the Rust programming language. See LICENSE.txt for terms of copyright and redistribution. See http://github.com/graydon/rust for current development page.