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      1 //===----- RemoteTargetExternal.h - LLVM out-of-process JIT execution -----===//
      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 // Definition of the RemoteTargetExternal class which executes JITed code in a
     11 // separate process from where it was built.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 
     15 #ifndef LLVM_TOOLS_LLI_REMOTETARGETEXTERNAL_H
     16 #define LLVM_TOOLS_LLI_REMOTETARGETEXTERNAL_H
     17 
     18 #include "RPCChannel.h"
     19 #include "RemoteTarget.h"
     20 #include "RemoteTargetMessage.h"
     21 #include "llvm/ADT/SmallVector.h"
     22 #include "llvm/ADT/StringRef.h"
     23 #include "llvm/Config/config.h"
     24 #include "llvm/Support/DataTypes.h"
     25 #include "llvm/Support/Memory.h"
     26 #include <stdlib.h>
     27 #include <string>
     28 
     29 namespace llvm {
     30 
     31 class RemoteTargetExternal : public RemoteTarget {
     32   RPCChannel RPC;
     33 
     34   bool WriteBytes(const void *Data, size_t Size) {
     35     return RPC.WriteBytes(Data, Size);
     36   }
     37 
     38   bool ReadBytes(void *Data, size_t Size) { return RPC.ReadBytes(Data, Size); }
     39 
     40 public:
     41   /// Allocate space in the remote target address space.
     42   ///
     43   /// @param      Size      Amount of space, in bytes, to allocate.
     44   /// @param      Alignment Required minimum alignment for allocated space.
     45   /// @param[out] Address   Remote address of the allocated memory.
     46   ///
     47   /// @returns True on success. On failure, ErrorMsg is updated with
     48   ///          descriptive text of the encountered error.
     49   bool allocateSpace(size_t Size, unsigned Alignment,
     50                      uint64_t &Address) override;
     51 
     52   /// Load data into the target address space.
     53   ///
     54   /// @param      Address   Destination address in the target process.
     55   /// @param      Data      Source address in the host process.
     56   /// @param      Size      Number of bytes to copy.
     57   ///
     58   /// @returns True on success. On failure, ErrorMsg is updated with
     59   ///          descriptive text of the encountered error.
     60   bool loadData(uint64_t Address, const void *Data, size_t Size) override;
     61 
     62   /// Load code into the target address space and prepare it for execution.
     63   ///
     64   /// @param      Address   Destination address in the target process.
     65   /// @param      Data      Source address in the host process.
     66   /// @param      Size      Number of bytes to copy.
     67   ///
     68   /// @returns True on success. On failure, ErrorMsg is updated with
     69   ///          descriptive text of the encountered error.
     70   bool loadCode(uint64_t Address, const void *Data, size_t Size) override;
     71 
     72   /// Execute code in the target process. The called function is required
     73   /// to be of signature int "(*)(void)".
     74   ///
     75   /// @param      Address   Address of the loaded function in the target
     76   ///                       process.
     77   /// @param[out] RetVal    The integer return value of the called function.
     78   ///
     79   /// @returns True on success. On failure, ErrorMsg is updated with
     80   ///          descriptive text of the encountered error.
     81   bool executeCode(uint64_t Address, int &RetVal) override;
     82 
     83   /// Minimum alignment for memory permissions. Used to separate code and
     84   /// data regions to make sure data doesn't get marked as code or vice
     85   /// versa.
     86   ///
     87   /// @returns Page alignment return value. Default of 4k.
     88   unsigned getPageAlignment() override { return 4096; }
     89 
     90   bool create() override {
     91     RPC.ChildName = ChildName;
     92     if (!RPC.createServer())
     93       return true;
     94 
     95     // We must get Ack from the client (blocking read)
     96     if (!Receive(LLI_ChildActive)) {
     97       ErrorMsg += ", (RPCChannel::create) - Stopping process!";
     98       stop();
     99       return false;
    100     }
    101 
    102     return true;
    103   }
    104 
    105   /// Terminate the remote process.
    106   void stop() override;
    107 
    108   RemoteTargetExternal(std::string &Name) : RemoteTarget(), ChildName(Name) {}
    109   ~RemoteTargetExternal() override {}
    110 
    111 private:
    112   std::string ChildName;
    113 
    114   bool SendAllocateSpace(uint32_t Alignment, uint32_t Size);
    115   bool SendLoadSection(uint64_t Addr,
    116                        const void *Data,
    117                        uint32_t Size,
    118                        bool IsCode);
    119   bool SendExecute(uint64_t Addr);
    120   bool SendTerminate();
    121 
    122   // High-level wrappers for receiving data
    123   bool Receive(LLIMessageType Msg);
    124   bool Receive(LLIMessageType Msg, int32_t &Data);
    125   bool Receive(LLIMessageType Msg, uint64_t &Data);
    126 
    127   // Lower level target-independent read/write to deal with errors
    128   bool ReceiveHeader(LLIMessageType Msg);
    129   bool ReceivePayload();
    130   bool SendHeader(LLIMessageType Msg);
    131   bool SendPayload();
    132 
    133   // Functions to append/retrieve data from the payload
    134   SmallVector<const void *, 2> SendData;
    135   SmallVector<void *, 1> ReceiveData; // Future proof
    136   SmallVector<int, 2> Sizes;
    137   void AppendWrite(const void *Data, uint32_t Size);
    138   void AppendRead(void *Data, uint32_t Size);
    139 };
    140 
    141 } // end namespace llvm
    142 
    143 #endif
    144