include/llvm/ExecutionEngine/Orc/JITSymbol.h

   1 //===----------- JITSymbol.h - JIT symbol abstraction -----------*- C++ -*-===//
   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 // Abstraction for target process addresses.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #ifndef LLVM_EXECUTIONENGINE_ORC_JITSYMBOL_H
  15 #define LLVM_EXECUTIONENGINE_ORC_JITSYMBOL_H
  16
  17 #include "llvm/Support/Compiler.h"
  18 #include <functional>
  19
  20 namespace llvm {
  21
  22 /// @brief Represents an address in the target process's address space.
  23 typedef uint64_t TargetAddress;
  24
  25 /// @brief Represents a symbol in the JIT.
  26 class JITSymbol {
  27 public:
  28   typedef std::function<TargetAddress()> GetAddressFtor;
  29
  30   JITSymbol(std::nullptr_t) : CachedAddr(0) {}
  31
  32   JITSymbol(GetAddressFtor GetAddress)
  33       : CachedAddr(0), GetAddress(std::move(GetAddress)) {}
  34
  35   /// @brief Returns true if the symbol exists, false otherwise.
  36   LLVM_EXPLICIT operator bool() const { return CachedAddr || GetAddress; }
  37
  38   /// @brief Get the address of the symbol in the target address space. Returns
  39   ///        '0' if the symbol does not exist.
  40   TargetAddress getAddress() {
  41     if (GetAddress) {
  42       CachedAddr = GetAddress();
  43       assert(CachedAddr && "Symbol could not be materialized.");
  44       GetAddress = nullptr;
  45     }
  46     return CachedAddr;
  47   }
  48
  49 private:
  50   TargetAddress CachedAddr;
  51   GetAddressFtor GetAddress;
  52 };
  53
  54 }
  55
  56 #endif // LLVM_EXECUTIONENGINE_ORC_JITSYMBOL_H