| //===-- StatepointDefaultGC.cpp - The default statepoint GC strategy ------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file contains a GCStrategy which serves as an example for the usage |
| // of a statepoint based lowering strategy. This GCStrategy is intended to |
| // suitable as a default implementation usable with any collector which can |
| // consume the standard stackmap format generated by statepoints, uses the |
| // default addrespace to distinguish between gc managed and non-gc managed |
| // pointers, and has reasonable relocation semantics. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/CodeGen/GCStrategy.h" |
| #include "llvm/IR/DerivedTypes.h" |
| #include "llvm/IR/Value.h" |
| |
| using namespace llvm; |
| |
| namespace { |
| class StatepointGC : public GCStrategy { |
| public: |
| StatepointGC() { |
| UseStatepoints = true; |
| // These options are all gc.root specific, we specify them so that the |
| // gc.root lowering code doesn't run. |
| InitRoots = false; |
| NeededSafePoints = 0; |
| UsesMetadata = false; |
| CustomRoots = false; |
| } |
| Optional<bool> isGCManagedPointer(const Type *Ty) const override { |
| // Method is only valid on pointer typed values. |
| const PointerType *PT = cast<PointerType>(Ty); |
| // For the sake of this example GC, we arbitrarily pick addrspace(1) as our |
| // GC managed heap. We know that a pointer into this heap needs to be |
| // updated and that no other pointer does. Note that addrspace(1) is used |
| // only as an example, it has no special meaning, and is not reserved for |
| // GC usage. |
| return (1 == PT->getAddressSpace()); |
| } |
| }; |
| } |
| |
| static GCRegistry::Add<StatepointGC> X("statepoint-example", |
| "an example strategy for statepoint"); |
| |
| namespace llvm { |
| void linkStatepointExampleGC() {} |
| } |