Factor GC metadata table assembly generation out of Collector in preparation for splitting AsmPrinter into its own library.

llvm-svn: 54881

Solanki!

llvm-svn: 53008

several things that were neither in an anonymous namespace nor static
but not intended to be global.

llvm-svn: 51017

llvm-svn: 45418

llvm-svn: 45034

per-function collector model. Collector is now the factory for
CollectorMetadata, so the latter may be subclassed.

llvm-svn: 44827

It includes:

 - location and of each safe point in machine code (identified by a
   label)
 - location of each root within the stack frame (identified by an
   offset), including the metadata tag provided to llvm.gcroot in
   the user program
 - size of the stack frame (for collectors which want to cheat on
   stack crawling :)
 - and eventually will include liveness

It is to be populated by back-ends during code-generation.

CollectorModuleMetadata aggregates this information across the
entire module.

llvm-svn: 42418