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