[llvm] r181466 - Pull up AssemblyWriter interface into header to allow subclassing

[Chris Lattner]

On May 8, 2013, at 1:38 PM, Daniel Malea <daniel.malea at intel.com> wrote:

> Author: dmalea
> Date: Wed May  8 15:38:31 2013
> New Revision: 181466
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=181466&view=rev
> Log:
> Pull up AssemblyWriter interface into header to allow subclassing
> - made all functions virtual so that subclasses can specialize them
> - add printInstructionLine so that subclasses can choose whether or not to
>  print the newline character (without having to implement printBasicBlock()
> - added a second constructor to AssemblyWriter that does not require a
>  SlotTracker, as required in order to keep the SlotTracker helper class outside
>  AsmWriter.h and buried in the implementation.

This is another *really* unfortunate change required by DebugIR.  Why is this functionality important, and why is this the right way to implement it?

-Chris