-//===-- llvm/CodeGen/Collector.h - Garbage collection -----------*- C++ -*-===//
+//===-- llvm/CodeGen/GCStrategy.h - Garbage collection ----------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
//
//===----------------------------------------------------------------------===//
//
-// Collector records sufficient information about a machine function to enable
-// accurate garbage collectors. Specifically:
+// GCStrategy coordinates code generation algorithms and implements some itself
+// in order to generate code compatible with a target code generator as
+// specified in a function's 'gc' attribute. Algorithms are enabled by setting
+// flags in a subclass's constructor, and some virtual methods can be
+// overridden.
+//
+// When requested, the GCStrategy will be populated with data about each
+// function which uses it. Specifically:
//
// - Safe points
-// Garbage collection is only possible at certain points in code. Code
-// generators should record points:
+// Garbage collection is generally only possible at certain points in code.
+// GCStrategy can request that the collector insert such points:
//
// - At and after any call to a subroutine
// - Before returning from the current function
// When a reference to a GC-allocated object exists on the stack, it must be
// stored in an alloca registered with llvm.gcoot.
//
-// This generic information should used by ABI-specific passes to emit support
-// tables for the runtime garbage collector.
-//
-// MachineCodeAnalysis identifies the GC safe points in the machine code. (Roots
-// are identified in SelectionDAGISel.)
+// This information can used to emit the metadata tables which are required by
+// the target garbage collector runtime.
//
//===----------------------------------------------------------------------===//
-#ifndef LLVM_CODEGEN_COLLECTOR_H
-#define LLVM_CODEGEN_COLLECTOR_H
+#ifndef LLVM_CODEGEN_GCSTRATEGY_H
+#define LLVM_CODEGEN_GCSTRATEGY_H
#include "llvm/CodeGen/GCMetadata.h"
+#include "llvm/Support/Registry.h"
#include <iosfwd>
#include <string>
namespace llvm {
- /// Collector describes a garbage collector's code generation requirements,
- /// and provides overridable hooks for those needs which cannot be abstractly
- /// described.
- class Collector {
+ class GCStrategy;
+
+ /// The GC strategy registry uses all the defaults from Registry.
+ ///
+ typedef Registry<GCStrategy> GCRegistry;
+
+ /// GCStrategy describes a garbage collector algorithm's code generation
+ /// requirements, and provides overridable hooks for those needs which cannot
+ /// be abstractly described.
+ class GCStrategy {
public:
- typedef std::vector<CollectorMetadata*> list_type;
+ typedef std::vector<GCFunctionInfo*> list_type;
typedef list_type::iterator iterator;
private:
- friend class CollectorModuleMetadata;
+ friend class GCModuleInfo;
const Module *M;
std::string Name;
bool UsesMetadata; //< If set, backend must emit metadata tables.
public:
- Collector();
+ GCStrategy();
- virtual ~Collector();
+ virtual ~GCStrategy();
- /// getName - The name of the collector, for debugging.
+ /// getName - The name of the GC strategy, for debugging.
///
const std::string &getName() const { return Name; }
- /// getModule - The module upon which the collector is operating.
+ /// getModule - The module within which the GC strategy is operating.
///
const Module &getModule() const { return *M; }
- /// True if this collector requires safe points of any kind. By default,
- /// none are recorded.
+ /// needsSafePoitns - True if safe points of any kind are required. By
+ // default, none are recorded.
bool needsSafePoints() const { return NeededSafePoints != 0; }
- /// True if the collector requires the given kind of safe point. By default,
- /// none are recorded.
+ /// needsSafePoint(Kind) - True if the given kind of safe point is
+ // required. By default, none are recorded.
bool needsSafePoint(GC::PointKind Kind) const {
return (NeededSafePoints & 1 << Kind) != 0;
}
- /// By default, write barriers are replaced with simple store instructions.
- /// If true, then addPassesToCustomLowerIntrinsics must instead process
- /// them.
+ /// customWriteBarrier - By default, write barriers are replaced with simple
+ /// store instructions. If true, then
+ /// performCustomLowering must instead lower them.
bool customWriteBarrier() const { return CustomWriteBarriers; }
- /// By default, read barriers are replaced with simple load instructions.
- /// If true, then addPassesToCustomLowerIntrinsics must instead process
- /// them.
+ /// customReadBarrier - By default, read barriers are replaced with simple
+ /// load instructions. If true, then
+ /// performCustomLowering must instead lower them.
bool customReadBarrier() const { return CustomReadBarriers; }
- /// By default, roots are left for the code generator. If Custom, then
- /// addPassesToCustomLowerIntrinsics must add passes to delete them.
+ /// customRoots - By default, roots are left for the code generator so it
+ /// can generate a stack map. If true, then
+ // performCustomLowering must delete them.
bool customRoots() const { return CustomRoots; }
- /// If set, gcroot intrinsics should initialize their allocas to null. This
- /// is necessary for most collectors.
+ /// initializeRoots - If set, gcroot intrinsics should initialize their
+ // allocas to null before the first use. This is
+ // necessary for most GCs and is enabled by default.
bool initializeRoots() const { return InitRoots; }
- /// If set, appropriate metadata tables must be emitted by the back-end
- /// (assembler, JIT, or otherwise).
+ /// usesMetadata - If set, appropriate metadata tables must be emitted by
+ /// the back-end (assembler, JIT, or otherwise).
bool usesMetadata() const { return UsesMetadata; }
/// begin/end - Iterators for function metadata.
/// insertFunctionMetadata - Creates metadata for a function.
///
- CollectorMetadata *insertFunctionMetadata(const Function &F);
+ GCFunctionInfo *insertFunctionInfo(const Function &F);
/// initializeCustomLowering/performCustomLowering - If any of the actions
- /// are set to custom, performCustomLowering must be overriden to create a
- /// transform to lower those actions to LLVM IR. initializeCustomLowering
- /// is optional to override. These are the only Collector methods through
+ /// are set to custom, performCustomLowering must be overriden to transform
+ /// the corresponding actions to LLVM IR. initializeCustomLowering is
+ /// optional to override. These are the only GCStrategy methods through
/// which the LLVM IR can be modified.
virtual bool initializeCustomLowering(Module &F);
virtual bool performCustomLowering(Function &F);
};
- // GCMetadataPrinter - Emits GC metadata as assembly code.
- class GCMetadataPrinter {
- public:
- typedef Collector::list_type list_type;
- typedef Collector::iterator iterator;
-
- private:
- Collector *Coll;
-
- friend class AsmPrinter;
-
- protected:
- // May only be subclassed.
- GCMetadataPrinter();
-
- // Do not implement.
- GCMetadataPrinter(const GCMetadataPrinter &);
- GCMetadataPrinter &operator=(const GCMetadataPrinter &);
-
- public:
- Collector &getCollector() { return *Coll; }
- const Module &getModule() const { return Coll->getModule(); }
-
- iterator begin() { return Coll->begin(); }
- iterator end() { return Coll->end(); }
-
- /// beginAssembly/finishAssembly - Emit module metadata as assembly code.
- virtual void beginAssembly(std::ostream &OS, AsmPrinter &AP,
- const TargetAsmInfo &TAI);
-
- virtual void finishAssembly(std::ostream &OS, AsmPrinter &AP,
- const TargetAsmInfo &TAI);
-
- virtual ~GCMetadataPrinter();
- };
-
}
#endif
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