llvm-svn: 77903

Generate code for the Blackfin family of DSPs from Analog Devices:

  http://www.analog.com/en/embedded-processing-dsp/blackfin/processors/index.html
  
We aim to be compatible with the exsisting GNU toolchain found at:

  http://blackfin.uclinux.org/gf/project/toolchain
  
The back-end is experimental.

llvm-svn: 77897