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 
WriteBytes(const void * Data,size_t Size)34   bool WriteBytes(const void *Data, size_t Size) {
35     return RPC.WriteBytes(Data, Size);
36   }
37 
ReadBytes(void * Data,size_t Size)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.
getPageAlignment()88   unsigned getPageAlignment() override { return 4096; }
89 
create()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 
RemoteTargetExternal(std::string & Name)108   RemoteTargetExternal(std::string &Name) : RemoteTarget(), ChildName(Name) {}
~RemoteTargetExternal()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