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
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42466 91177308-0d34-0410-b5e6-96231b3b80d8
