that "machine" classes are used to represent the current state of
the code being compiled.  Given this expanded name, we can start 
moving other stuff into it.  For now, move the UsedPhysRegs and
LiveIn/LoveOuts vectors from MachineFunction into it.

Update all the clients to match.

This also reduces some needless #includes, such as MachineModuleInfo
from MachineFunction.

llvm-svn: 45467

llvm-svn: 45418

fixes a bug with indirect calls. (Test case will be included with
ocaml collector patch.)

llvm-svn: 45316

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

llvm-svn: 44827

This version enhances the previous patch to add root initialization
as discussed here:

http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20070910/053455.html

Collector gives its subclasses control over generic algorithms:

  unsigned NeededSafePoints; //< Bitmask of required safe points.
  bool CustomReadBarriers;   //< Default is to insert loads.
  bool CustomWriteBarriers;  //< Default is to insert stores.
  bool CustomRoots;          //< Default is to pass through to backend.
  bool InitRoots;            //< If set, roots are nulled during lowering.

It also has callbacks which collectors can hook:

  /// If any of the actions are set to Custom, this is expected to
  /// be overriden to create a transform to lower those actions to
  /// LLVM IR.
  virtual Pass *createCustomLoweringPass() const;

  /// beginAssembly/finishAssembly - Emit module metadata as
  /// assembly code.
  virtual void beginAssembly(Module &M, std::ostream &OS,
                             AsmPrinter &AP,
                             const TargetAsmInfo &TAI) const;
  virtual void finishAssembly(Module &M,
                              CollectorModuleMetadata &CMM,
                              std::ostream &OS, AsmPrinter &AP,
                              const TargetAsmInfo &TAI) const;  

Various other independent algorithms could be implemented, but were
not necessary for the initial two collectors. Some examples are
listed here:

http://llvm.org/docs/GarbageCollection.html#collector-algos

llvm-svn: 42466