This isn't supposed to be a blog about getting a LanuchPad toolset running on my Mac, so I'm not going to talk much about that adventure. At least not here. In the interest of maintaining the multi-platform spirit of Arduino, and because I do most of my work on a Mac, I will mostly be avoiding the TI provided tools (which run only under Windows.) (TI does have a compatibility matrix for running their tools under windows on a Mac using assorted virtual machines.) Arduino uses gcc (the Gnu Compiler Collection), and there already exists an MPS430 version of gcc, and I've been using gcc on other cpus for over 20 years now, so it is a natural choice.
gcc is generally an adequate (or better) compiler for CPUs that are close to its general model of how a cpu ought to behave. The MSP430 fits that description (actually, rather better than the AVR does), and so far I've been pleased with the code that gcc produces. I've heard rumours of bugs in the compiler, and I've even found some bugs in include files, but ... that's par for the course. Speaking as a hobbyist and/or non-technical user (the target audience for Arduino, remember), having a compiler supported by a large community can be better than having a compiler supported by a large company, even if the latter is likely to be more timely and aggressive about fixing bugs. Since gcc is a simple command-line based compiler, it is pretty easy to get running on any operating system...
There are frequently different behaviors in compilers when it comes to the "edges" of what is defined by the language involved. In the case of the MSP430, this means things like interrupt service routines, interfaces to assembly language, putting constants in flash memory, and stuff like that. I'll try to highlight such issues as I go along.
The other tool needed is some sort of device programmer for actually loading code onto the chips. This is actually a pretty significant problem, since programming tools tend to be low-volume proprietary hardware. Arduino uses a serial bootloader, but the LaunchPad lacks the "extra" program space for such luxuries. There seem to be a couple of Linux tools for talking to TI programmers, and I've been able to get one of them (mspdebug) working on the Mac (at least for some programmers.)
So I can write code, and I can load it onto chips. The same tools run on Mac, Linux and (probably) Windows. That should be all I'll need. mspdebug actually supports some relatively powerful debugging, so I'm theoretically in great shape.
http://mspgcc.sourceforge.net/ main page for msp430 gcc information.
http://mspgcc4.sourceforge.net/ mspgcc version 4 "daughter page." This is what I'm using.
http://mspdebug.sourceforge.net/ main page for mspdebug.