1//===-- RTDyldMemoryManager.cpp - Memory manager for MC-JIT -----*- 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// Interface of the runtime dynamic memory manager base class.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_EXECUTIONENGINE_RTDYLDMEMORYMANAGER_H
15#define LLVM_EXECUTIONENGINE_RTDYLDMEMORYMANAGER_H
16
17#include "llvm-c/ExecutionEngine.h"
18#include "llvm/ExecutionEngine/JITSymbol.h"
19#include "llvm/ExecutionEngine/RuntimeDyld.h"
20#include "llvm/Support/CBindingWrapping.h"
21#include <cstddef>
22#include <cstdint>
23#include <string>
24
25namespace llvm {
26
27class ExecutionEngine;
28
29namespace object {
30  class ObjectFile;
31} // end namespace object
32
33class MCJITMemoryManager : public RuntimeDyld::MemoryManager {
34public:
35  // Don't hide the notifyObjectLoaded method from RuntimeDyld::MemoryManager.
36  using RuntimeDyld::MemoryManager::notifyObjectLoaded;
37
38  /// This method is called after an object has been loaded into memory but
39  /// before relocations are applied to the loaded sections.  The object load
40  /// may have been initiated by MCJIT to resolve an external symbol for another
41  /// object that is being finalized.  In that case, the object about which
42  /// the memory manager is being notified will be finalized immediately after
43  /// the memory manager returns from this call.
44  ///
45  /// Memory managers which are preparing code for execution in an external
46  /// address space can use this call to remap the section addresses for the
47  /// newly loaded object.
48  virtual void notifyObjectLoaded(ExecutionEngine *EE,
49                                  const object::ObjectFile &) {}
50};
51
52// RuntimeDyld clients often want to handle the memory management of
53// what gets placed where. For JIT clients, this is the subset of
54// JITMemoryManager required for dynamic loading of binaries.
55//
56// FIXME: As the RuntimeDyld fills out, additional routines will be needed
57//        for the varying types of objects to be allocated.
58class RTDyldMemoryManager : public MCJITMemoryManager,
59                            public JITSymbolResolver {
60public:
61  RTDyldMemoryManager() = default;
62  RTDyldMemoryManager(const RTDyldMemoryManager&) = delete;
63  void operator=(const RTDyldMemoryManager&) = delete;
64  ~RTDyldMemoryManager() override;
65
66  /// Register EH frames in the current process.
67  static void registerEHFramesInProcess(uint8_t *Addr, size_t Size);
68
69  /// Deregister EH frames in the current proces.
70  static void deregisterEHFramesInProcess(uint8_t *Addr, size_t Size);
71
72  void registerEHFrames(uint8_t *Addr, uint64_t LoadAddr, size_t Size) override;
73  void deregisterEHFrames() override;
74
75  /// This method returns the address of the specified function or variable in
76  /// the current process.
77  static uint64_t getSymbolAddressInProcess(const std::string &Name);
78
79  /// Legacy symbol lookup - DEPRECATED! Please override findSymbol instead.
80  ///
81  /// This method returns the address of the specified function or variable.
82  /// It is used to resolve symbols during module linking.
83  virtual uint64_t getSymbolAddress(const std::string &Name) {
84    return getSymbolAddressInProcess(Name);
85  }
86
87  /// This method returns a RuntimeDyld::SymbolInfo for the specified function
88  /// or variable. It is used to resolve symbols during module linking.
89  ///
90  /// By default this falls back on the legacy lookup method:
91  /// 'getSymbolAddress'. The address returned by getSymbolAddress is treated as
92  /// a strong, exported symbol, consistent with historical treatment by
93  /// RuntimeDyld.
94  ///
95  /// Clients writing custom RTDyldMemoryManagers are encouraged to override
96  /// this method and return a SymbolInfo with the flags set correctly. This is
97  /// necessary for RuntimeDyld to correctly handle weak and non-exported symbols.
98  JITSymbol findSymbol(const std::string &Name) override {
99    return JITSymbol(getSymbolAddress(Name), JITSymbolFlags::Exported);
100  }
101
102  /// Legacy symbol lookup -- DEPRECATED! Please override
103  /// findSymbolInLogicalDylib instead.
104  ///
105  /// Default to treating all modules as separate.
106  virtual uint64_t getSymbolAddressInLogicalDylib(const std::string &Name) {
107    return 0;
108  }
109
110  /// Default to treating all modules as separate.
111  ///
112  /// By default this falls back on the legacy lookup method:
113  /// 'getSymbolAddressInLogicalDylib'. The address returned by
114  /// getSymbolAddressInLogicalDylib is treated as a strong, exported symbol,
115  /// consistent with historical treatment by RuntimeDyld.
116  ///
117  /// Clients writing custom RTDyldMemoryManagers are encouraged to override
118  /// this method and return a SymbolInfo with the flags set correctly. This is
119  /// necessary for RuntimeDyld to correctly handle weak and non-exported symbols.
120  JITSymbol
121  findSymbolInLogicalDylib(const std::string &Name) override {
122    return JITSymbol(getSymbolAddressInLogicalDylib(Name),
123                          JITSymbolFlags::Exported);
124  }
125
126  /// This method returns the address of the specified function. As such it is
127  /// only useful for resolving library symbols, not code generated symbols.
128  ///
129  /// If \p AbortOnFailure is false and no function with the given name is
130  /// found, this function returns a null pointer. Otherwise, it prints a
131  /// message to stderr and aborts.
132  ///
133  /// This function is deprecated for memory managers to be used with
134  /// MCJIT or RuntimeDyld.  Use getSymbolAddress instead.
135  virtual void *getPointerToNamedFunction(const std::string &Name,
136                                          bool AbortOnFailure = true);
137
138private:
139  struct EHFrame {
140    uint8_t *Addr;
141    size_t Size;
142  };
143  std::vector<EHFrame> EHFrames;
144};
145
146// Create wrappers for C Binding types (see CBindingWrapping.h).
147DEFINE_SIMPLE_CONVERSION_FUNCTIONS(
148    RTDyldMemoryManager, LLVMMCJITMemoryManagerRef)
149
150} // end namespace llvm
151
152#endif // LLVM_EXECUTIONENGINE_RTDYLDMEMORYMANAGER_H
153