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      1 //===- RemoteMemoryManager.h - LLI MCJIT recording memory manager ------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This memory manager allocates local storage and keeps a record of each
     11 // allocation. Iterators are provided for all data and code allocations.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 
     15 #ifndef REMOTEMEMORYMANAGER_H
     16 #define REMOTEMEMORYMANAGER_H
     17 
     18 #include "RemoteTarget.h"
     19 #include "llvm/ADT/DenseMap.h"
     20 #include "llvm/ADT/SmallVector.h"
     21 #include "llvm/ExecutionEngine/JITMemoryManager.h"
     22 #include "llvm/Support/ErrorHandling.h"
     23 #include "llvm/Support/Memory.h"
     24 #include <utility>
     25 
     26 namespace llvm {
     27 
     28 class RemoteMemoryManager : public JITMemoryManager {
     29 public:
     30   // Notice that this structure takes ownership of the memory allocated.
     31   struct Allocation {
     32     Allocation() {}
     33     Allocation(sys::MemoryBlock mb, unsigned a, bool code)
     34       : MB(mb), Alignment(a), IsCode(code) {}
     35 
     36     sys::MemoryBlock  MB;
     37     unsigned          Alignment;
     38     bool              IsCode;
     39   };
     40 
     41 private:
     42   // This vector contains Allocation objects for all sections which we have
     43   // allocated.  This vector effectively owns the memory associated with the
     44   // allocations.
     45   SmallVector<Allocation, 2>  AllocatedSections;
     46 
     47   // This vector contains pointers to Allocation objects for any sections we
     48   // have allocated locally but have not yet remapped for the remote target.
     49   // When we receive notification of a completed module load, we will map
     50   // these sections into the remote target.
     51   SmallVector<Allocation, 2>  UnmappedSections;
     52 
     53   // This map tracks the sections we have remapped for the remote target
     54   // but have not yet copied to the target.
     55   DenseMap<uint64_t, Allocation>  MappedSections;
     56 
     57   // FIXME: This is part of a work around to keep sections near one another
     58   // when MCJIT performs relocations after code emission but before
     59   // the generated code is moved to the remote target.
     60   sys::MemoryBlock Near;
     61   sys::MemoryBlock allocateSection(uintptr_t Size);
     62 
     63   RemoteTarget *Target;
     64 
     65 public:
     66   RemoteMemoryManager() : Target(nullptr) {}
     67   virtual ~RemoteMemoryManager();
     68 
     69   uint8_t *allocateCodeSection(uintptr_t Size, unsigned Alignment,
     70                                unsigned SectionID,
     71                                StringRef SectionName) override;
     72 
     73   uint8_t *allocateDataSection(uintptr_t Size, unsigned Alignment,
     74                                unsigned SectionID, StringRef SectionName,
     75                                bool IsReadOnly) override;
     76 
     77   // For now, remote symbol resolution is not support in lli.  The MCJIT
     78   // interface does support this, but clients must provide their own
     79   // mechanism for finding remote symbol addresses.  MCJIT will resolve
     80   // symbols from Modules it contains.
     81   uint64_t getSymbolAddress(const std::string &Name) override { return 0; }
     82 
     83   void notifyObjectLoaded(ExecutionEngine *EE, const ObjectImage *Obj) override;
     84 
     85   bool finalizeMemory(std::string *ErrMsg) override;
     86 
     87   // For now, remote EH frame registration isn't supported.  Remote symbol
     88   // resolution is a prerequisite to supporting remote EH frame registration.
     89   void registerEHFrames(uint8_t *Addr, uint64_t LoadAddr,
     90                         size_t Size) override {}
     91   void deregisterEHFrames(uint8_t *Addr, uint64_t LoadAddr,
     92                           size_t Size) override {}
     93 
     94   // This is a non-interface function used by lli
     95   void setRemoteTarget(RemoteTarget *T) { Target = T; }
     96 
     97   // The following obsolete JITMemoryManager calls are stubbed out for
     98   // this model.
     99   void setMemoryWritable() override;
    100   void setMemoryExecutable() override;
    101   void setPoisonMemory(bool poison) override;
    102   void AllocateGOT() override;
    103   uint8_t *getGOTBase() const override;
    104   uint8_t *startFunctionBody(const Function *F, uintptr_t &ActualSize) override;
    105   uint8_t *allocateStub(const GlobalValue* F, unsigned StubSize,
    106                         unsigned Alignment) override;
    107   void endFunctionBody(const Function *F, uint8_t *FunctionStart,
    108                        uint8_t *FunctionEnd) override;
    109   uint8_t *allocateSpace(intptr_t Size, unsigned Alignment) override;
    110   uint8_t *allocateGlobal(uintptr_t Size, unsigned Alignment) override;
    111   void deallocateFunctionBody(void *Body) override;
    112 };
    113 
    114 } // end namespace llvm
    115 
    116 #endif
    117