MemoryMapper.h

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//===- MemoryMapper.h - Cross-process memory mapper -------------*- 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
//
//===----------------------------------------------------------------------===//
//
// Cross-process (and in-process) memory mapping and transfer
//
//===----------------------------------------------------------------------===//
 
#ifndef LLVM_EXECUTIONENGINE_ORC_MEMORYMAPPER_H
#define LLVM_EXECUTIONENGINE_ORC_MEMORYMAPPER_H
 
#include "llvm/ExecutionEngine/Orc/Core.h"
#include "llvm/ExecutionEngine/Orc/Shared/MemoryFlags.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Process.h"
 
#include <mutex>
 
namespace llvm {
namespace orc {
 
/// Manages mapping, content transfer and protections for JIT memory
class LLVM_ABI MemoryMapper {
public:
  /// Represents a single allocation containing multiple segments and
  /// initialization and deinitialization actions
  struct AllocInfo {
    struct SegInfo {
      ExecutorAddrDiff Offset;
      const char *WorkingMem;
      size_t ContentSize;
      size_t ZeroFillSize;
      AllocGroup AG;
    };
 
    ExecutorAddr MappingBase;
    std::vector<SegInfo> Segments;
    shared::AllocActions Actions;
  };
 
  using OnReservedFunction = unique_function<void(Expected<ExecutorAddrRange>)>;
 
  // Page size of the target process
  virtual unsigned int getPageSize() = 0;
 
  /// Reserves address space in executor process
  virtual void reserve(size_t NumBytes, OnReservedFunction OnReserved) = 0;
 
  /// Provides working memory
  /// The LinkGraph parameter is included to allow implementations to allocate
  /// working memory from the LinkGraph's allocator, in which case it will be
  /// deallocated when the LinkGraph is destroyed.
  virtual char *prepare(jitlink::LinkGraph &G, ExecutorAddr Addr,
                        size_t ContentSize) = 0;
 
  using OnInitializedFunction = unique_function<void(Expected<ExecutorAddr>)>;
 
  /// Ensures executor memory is synchronized with working copy memory, sends
  /// functions to be called after initilization and before deinitialization and
  /// applies memory protections
  /// Returns a unique address identifying the allocation. This address should
  /// be passed to deinitialize to run deallocation actions (and reset
  /// permissions where possible).
  virtual void initialize(AllocInfo &AI,
                          OnInitializedFunction OnInitialized) = 0;
 
  using OnDeinitializedFunction = unique_function<void(Error)>;
 
  /// Runs previously specified deinitialization actions
  /// Executor addresses returned by initialize should be passed
  virtual void deinitialize(ArrayRef<ExecutorAddr> Allocations,
                            OnDeinitializedFunction OnDeInitialized) = 0;
 
  using OnReleasedFunction = unique_function<void(Error)>;
 
  /// Release address space acquired through reserve()
  virtual void release(ArrayRef<ExecutorAddr> Reservations,
                       OnReleasedFunction OnRelease) = 0;
 
  virtual ~MemoryMapper();
};
 
class LLVM_ABI InProcessMemoryMapper : public MemoryMapper {
public:
  InProcessMemoryMapper(size_t PageSize);
 
  static Expected<std::unique_ptr<InProcessMemoryMapper>> Create();
 
  unsigned int getPageSize() override { return PageSize; }
 
  void reserve(size_t NumBytes, OnReservedFunction OnReserved) override;
 
  void initialize(AllocInfo &AI, OnInitializedFunction OnInitialized) override;
 
  char *prepare(jitlink::LinkGraph &G, ExecutorAddr Addr,
                size_t ContentSize) override;
 
  void deinitialize(ArrayRef<ExecutorAddr> Allocations,
                    OnDeinitializedFunction OnDeInitialized) override;
 
  void release(ArrayRef<ExecutorAddr> Reservations,
               OnReleasedFunction OnRelease) override;
 
  ~InProcessMemoryMapper() override;
 
private:
  struct Allocation {
    size_t Size;
    std::vector<shared::WrapperFunctionCall> DeinitializationActions;
  };
  using AllocationMap = DenseMap<ExecutorAddr, Allocation>;
 
  struct Reservation {
    size_t Size;
    std::vector<ExecutorAddr> Allocations;
  };
  using ReservationMap = DenseMap<void *, Reservation>;
 
  std::mutex Mutex;
  ReservationMap Reservations;
  AllocationMap Allocations;
 
  size_t PageSize;
};
 
class LLVM_ABI SharedMemoryMapper final : public MemoryMapper {
public:
  struct SymbolAddrs {
    ExecutorAddr Instance;
    ExecutorAddr Reserve;
    ExecutorAddr Initialize;
    ExecutorAddr Deinitialize;
    ExecutorAddr Release;
  };
 
  SharedMemoryMapper(ExecutorProcessControl &EPC, SymbolAddrs SAs,
                     size_t PageSize);
 
  static Expected<std::unique_ptr<SharedMemoryMapper>>
  Create(ExecutorProcessControl &EPC, SymbolAddrs SAs);
 
  unsigned int getPageSize() override { return PageSize; }
 
  void reserve(size_t NumBytes, OnReservedFunction OnReserved) override;
 
  char *prepare(jitlink::LinkGraph &G, ExecutorAddr Addr,
                size_t ContentSize) override;
 
  void initialize(AllocInfo &AI, OnInitializedFunction OnInitialized) override;
 
  void deinitialize(ArrayRef<ExecutorAddr> Allocations,
                    OnDeinitializedFunction OnDeInitialized) override;
 
  void release(ArrayRef<ExecutorAddr> Reservations,
               OnReleasedFunction OnRelease) override;
 
  ~SharedMemoryMapper() override;
 
private:
  struct Reservation {
    void *LocalAddr;
    size_t Size;
    int SharedMemoryId;
  };
 
  ExecutorProcessControl &EPC;
  SymbolAddrs SAs;
 
  std::mutex Mutex;
 
  std::map<ExecutorAddr, Reservation> Reservations;
 
  size_t PageSize;
};
 
} // namespace orc
} // end namespace llvm
 
#endif // LLVM_EXECUTIONENGINE_ORC_MEMORYMAPPER_H