206 lines
7.2 KiB
C++
206 lines
7.2 KiB
C++
//===- GCMetadata.h - Garbage collector metadata ----------------*- C++ -*-===//
|
|
//
|
|
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
|
|
// See https://llvm.org/LICENSE.txt for license information.
|
|
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file declares the GCFunctionInfo and GCModuleInfo classes, which are
|
|
// used as a communication channel from the target code generator to the target
|
|
// garbage collectors. This interface allows code generators and garbage
|
|
// collectors to be developed independently.
|
|
//
|
|
// The GCFunctionInfo class logs the data necessary to build a type accurate
|
|
// stack map. The code generator outputs:
|
|
//
|
|
// - Safe points as specified by the GCStrategy's NeededSafePoints.
|
|
// - Stack offsets for GC roots, as specified by calls to llvm.gcroot
|
|
//
|
|
// As a refinement, liveness analysis calculates the set of live roots at each
|
|
// safe point. Liveness analysis is not presently performed by the code
|
|
// generator, so all roots are assumed live.
|
|
//
|
|
// GCModuleInfo simply collects GCFunctionInfo instances for each Function as
|
|
// they are compiled. This accretion is necessary for collectors which must emit
|
|
// a stack map for the compilation unit as a whole. Therefore, GCFunctionInfo
|
|
// outlives the MachineFunction from which it is derived and must not refer to
|
|
// any code generator data structures.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#ifndef LLVM_CODEGEN_GCMETADATA_H
|
|
#define LLVM_CODEGEN_GCMETADATA_H
|
|
|
|
#include "llvm/ADT/DenseMap.h"
|
|
#include "llvm/ADT/SmallVector.h"
|
|
#include "llvm/ADT/StringMap.h"
|
|
#include "llvm/ADT/StringRef.h"
|
|
#include "llvm/CodeGen/GCStrategy.h"
|
|
#include "llvm/IR/DebugLoc.h"
|
|
#include "llvm/Pass.h"
|
|
#include <algorithm>
|
|
#include <cstddef>
|
|
#include <cstdint>
|
|
#include <memory>
|
|
#include <vector>
|
|
|
|
namespace llvm {
|
|
|
|
class Constant;
|
|
class Function;
|
|
class MCSymbol;
|
|
|
|
/// GCPoint - Metadata for a collector-safe point in machine code.
|
|
///
|
|
struct GCPoint {
|
|
MCSymbol *Label; ///< A label.
|
|
DebugLoc Loc;
|
|
|
|
GCPoint(MCSymbol *L, DebugLoc DL)
|
|
: Label(L), Loc(std::move(DL)) {}
|
|
};
|
|
|
|
/// GCRoot - Metadata for a pointer to an object managed by the garbage
|
|
/// collector.
|
|
struct GCRoot {
|
|
int Num; ///< Usually a frame index.
|
|
int StackOffset = -1; ///< Offset from the stack pointer.
|
|
const Constant *Metadata; ///< Metadata straight from the call
|
|
///< to llvm.gcroot.
|
|
|
|
GCRoot(int N, const Constant *MD) : Num(N), Metadata(MD) {}
|
|
};
|
|
|
|
/// Garbage collection metadata for a single function. Currently, this
|
|
/// information only applies to GCStrategies which use GCRoot.
|
|
class GCFunctionInfo {
|
|
public:
|
|
using iterator = std::vector<GCPoint>::iterator;
|
|
using roots_iterator = std::vector<GCRoot>::iterator;
|
|
using live_iterator = std::vector<GCRoot>::const_iterator;
|
|
|
|
private:
|
|
const Function &F;
|
|
GCStrategy &S;
|
|
uint64_t FrameSize;
|
|
std::vector<GCRoot> Roots;
|
|
std::vector<GCPoint> SafePoints;
|
|
|
|
// FIXME: Liveness. A 2D BitVector, perhaps?
|
|
//
|
|
// BitVector Liveness;
|
|
//
|
|
// bool islive(int point, int root) =
|
|
// Liveness[point * SafePoints.size() + root]
|
|
//
|
|
// The bit vector is the more compact representation where >3.2% of roots
|
|
// are live per safe point (1.5% on 64-bit hosts).
|
|
|
|
public:
|
|
GCFunctionInfo(const Function &F, GCStrategy &S);
|
|
~GCFunctionInfo();
|
|
|
|
/// getFunction - Return the function to which this metadata applies.
|
|
const Function &getFunction() const { return F; }
|
|
|
|
/// getStrategy - Return the GC strategy for the function.
|
|
GCStrategy &getStrategy() { return S; }
|
|
|
|
/// addStackRoot - Registers a root that lives on the stack. Num is the
|
|
/// stack object ID for the alloca (if the code generator is
|
|
// using MachineFrameInfo).
|
|
void addStackRoot(int Num, const Constant *Metadata) {
|
|
Roots.push_back(GCRoot(Num, Metadata));
|
|
}
|
|
|
|
/// removeStackRoot - Removes a root.
|
|
roots_iterator removeStackRoot(roots_iterator position) {
|
|
return Roots.erase(position);
|
|
}
|
|
|
|
/// addSafePoint - Notes the existence of a safe point. Num is the ID of the
|
|
/// label just prior to the safe point (if the code generator is using
|
|
/// MachineModuleInfo).
|
|
void addSafePoint(MCSymbol *Label, const DebugLoc &DL) {
|
|
SafePoints.emplace_back(Label, DL);
|
|
}
|
|
|
|
/// getFrameSize/setFrameSize - Records the function's frame size.
|
|
uint64_t getFrameSize() const { return FrameSize; }
|
|
void setFrameSize(uint64_t S) { FrameSize = S; }
|
|
|
|
/// begin/end - Iterators for safe points.
|
|
iterator begin() { return SafePoints.begin(); }
|
|
iterator end() { return SafePoints.end(); }
|
|
size_t size() const { return SafePoints.size(); }
|
|
|
|
/// roots_begin/roots_end - Iterators for all roots in the function.
|
|
roots_iterator roots_begin() { return Roots.begin(); }
|
|
roots_iterator roots_end() { return Roots.end(); }
|
|
size_t roots_size() const { return Roots.size(); }
|
|
|
|
/// live_begin/live_end - Iterators for live roots at a given safe point.
|
|
live_iterator live_begin(const iterator &p) { return roots_begin(); }
|
|
live_iterator live_end(const iterator &p) { return roots_end(); }
|
|
size_t live_size(const iterator &p) const { return roots_size(); }
|
|
};
|
|
|
|
/// An analysis pass which caches information about the entire Module.
|
|
/// Records both the function level information used by GCRoots and a
|
|
/// cache of the 'active' gc strategy objects for the current Module.
|
|
class GCModuleInfo : public ImmutablePass {
|
|
/// An owning list of all GCStrategies which have been created
|
|
SmallVector<std::unique_ptr<GCStrategy>, 1> GCStrategyList;
|
|
/// A helper map to speedup lookups into the above list
|
|
StringMap<GCStrategy*> GCStrategyMap;
|
|
|
|
public:
|
|
/// Lookup the GCStrategy object associated with the given gc name.
|
|
/// Objects are owned internally; No caller should attempt to delete the
|
|
/// returned objects.
|
|
GCStrategy *getGCStrategy(const StringRef Name);
|
|
|
|
/// List of per function info objects. In theory, Each of these
|
|
/// may be associated with a different GC.
|
|
using FuncInfoVec = std::vector<std::unique_ptr<GCFunctionInfo>>;
|
|
|
|
FuncInfoVec::iterator funcinfo_begin() { return Functions.begin(); }
|
|
FuncInfoVec::iterator funcinfo_end() { return Functions.end(); }
|
|
|
|
private:
|
|
/// Owning list of all GCFunctionInfos associated with this Module
|
|
FuncInfoVec Functions;
|
|
|
|
/// Non-owning map to bypass linear search when finding the GCFunctionInfo
|
|
/// associated with a particular Function.
|
|
using finfo_map_type = DenseMap<const Function *, GCFunctionInfo *>;
|
|
finfo_map_type FInfoMap;
|
|
|
|
public:
|
|
using iterator = SmallVector<std::unique_ptr<GCStrategy>, 1>::const_iterator;
|
|
|
|
static char ID;
|
|
|
|
GCModuleInfo();
|
|
|
|
/// clear - Resets the pass. Any pass, which uses GCModuleInfo, should
|
|
/// call it in doFinalization().
|
|
///
|
|
void clear();
|
|
|
|
/// begin/end - Iterators for used strategies.
|
|
///
|
|
iterator begin() const { return GCStrategyList.begin(); }
|
|
iterator end() const { return GCStrategyList.end(); }
|
|
|
|
/// get - Look up function metadata. This is currently assumed
|
|
/// have the side effect of initializing the associated GCStrategy. That
|
|
/// will soon change.
|
|
GCFunctionInfo &getFunctionInfo(const Function &F);
|
|
};
|
|
|
|
} // end namespace llvm
|
|
|
|
#endif // LLVM_CODEGEN_GCMETADATA_H
|