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