LLVM  6.0.0svn
RuntimeDyld.h
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1 //===- RuntimeDyld.h - Run-time dynamic linker 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 for the runtime dynamic linker facilities of the MC-JIT.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_EXECUTIONENGINE_RUNTIMEDYLD_H
15 #define LLVM_EXECUTIONENGINE_RUNTIMEDYLD_H
16 
17 #include "llvm/ADT/STLExtras.h"
18 #include "llvm/ADT/StringRef.h"
21 #include "llvm/Object/ObjectFile.h"
22 #include "llvm/Support/Error.h"
23 #include <algorithm>
24 #include <cassert>
25 #include <cstddef>
26 #include <cstdint>
27 #include <map>
28 #include <memory>
29 #include <string>
30 #include <system_error>
31 
32 namespace llvm {
33 
34 namespace object {
35 
36 template <typename T> class OwningBinary;
37 
38 } // end namespace object
39 
40 /// Base class for errors originating in RuntimeDyld, e.g. missing relocation
41 /// support.
42 class RuntimeDyldError : public ErrorInfo<RuntimeDyldError> {
43 public:
44  static char ID;
45 
46  RuntimeDyldError(std::string ErrMsg) : ErrMsg(std::move(ErrMsg)) {}
47 
48  void log(raw_ostream &OS) const override;
49  const std::string &getErrorMessage() const { return ErrMsg; }
50  std::error_code convertToErrorCode() const override;
51 
52 private:
53  std::string ErrMsg;
54 };
55 
57 class RuntimeDyldImpl;
58 
59 class RuntimeDyld {
60  friend class RuntimeDyldCheckerImpl;
61 
62 protected:
63  // Change the address associated with a section when resolving relocations.
64  // Any relocations already associated with the symbol will be re-resolved.
65  void reassignSectionAddress(unsigned SectionID, uint64_t Addr);
66 
67 public:
68  /// \brief Information about the loaded object.
70  friend class RuntimeDyldImpl;
71 
72  public:
73  using ObjSectionToIDMap = std::map<object::SectionRef, unsigned>;
74 
76  : RTDyld(RTDyld), ObjSecToIDMap(std::move(ObjSecToIDMap)) {}
77 
79  getObjectForDebug(const object::ObjectFile &Obj) const = 0;
80 
81  uint64_t
82  getSectionLoadAddress(const object::SectionRef &Sec) const override;
83 
84  protected:
85  virtual void anchor();
86 
89  };
90 
91  /// \brief Memory Management.
92  class MemoryManager {
93  friend class RuntimeDyld;
94 
95  public:
96  MemoryManager() = default;
97  virtual ~MemoryManager() = default;
98 
99  /// Allocate a memory block of (at least) the given size suitable for
100  /// executable code. The SectionID is a unique identifier assigned by the
101  /// RuntimeDyld instance, and optionally recorded by the memory manager to
102  /// access a loaded section.
103  virtual uint8_t *allocateCodeSection(uintptr_t Size, unsigned Alignment,
104  unsigned SectionID,
105  StringRef SectionName) = 0;
106 
107  /// Allocate a memory block of (at least) the given size suitable for data.
108  /// The SectionID is a unique identifier assigned by the JIT engine, and
109  /// optionally recorded by the memory manager to access a loaded section.
110  virtual uint8_t *allocateDataSection(uintptr_t Size, unsigned Alignment,
111  unsigned SectionID,
113  bool IsReadOnly) = 0;
114 
115  /// Inform the memory manager about the total amount of memory required to
116  /// allocate all sections to be loaded:
117  /// \p CodeSize - the total size of all code sections
118  /// \p DataSizeRO - the total size of all read-only data sections
119  /// \p DataSizeRW - the total size of all read-write data sections
120  ///
121  /// Note that by default the callback is disabled. To enable it
122  /// redefine the method needsToReserveAllocationSpace to return true.
123  virtual void reserveAllocationSpace(uintptr_t CodeSize, uint32_t CodeAlign,
124  uintptr_t RODataSize,
125  uint32_t RODataAlign,
126  uintptr_t RWDataSize,
127  uint32_t RWDataAlign) {}
128 
129  /// Override to return true to enable the reserveAllocationSpace callback.
130  virtual bool needsToReserveAllocationSpace() { return false; }
131 
132  /// Register the EH frames with the runtime so that c++ exceptions work.
133  ///
134  /// \p Addr parameter provides the local address of the EH frame section
135  /// data, while \p LoadAddr provides the address of the data in the target
136  /// address space. If the section has not been remapped (which will usually
137  /// be the case for local execution) these two values will be the same.
138  virtual void registerEHFrames(uint8_t *Addr, uint64_t LoadAddr,
139  size_t Size) = 0;
140  virtual void deregisterEHFrames() = 0;
141 
142  /// This method is called when object loading is complete and section page
143  /// permissions can be applied. It is up to the memory manager implementation
144  /// to decide whether or not to act on this method. The memory manager will
145  /// typically allocate all sections as read-write and then apply specific
146  /// permissions when this method is called. Code sections cannot be executed
147  /// until this function has been called. In addition, any cache coherency
148  /// operations needed to reliably use the memory are also performed.
149  ///
150  /// Returns true if an error occurred, false otherwise.
151  virtual bool finalizeMemory(std::string *ErrMsg = nullptr) = 0;
152 
153  /// This method is called after an object has been loaded into memory but
154  /// before relocations are applied to the loaded sections.
155  ///
156  /// Memory managers which are preparing code for execution in an external
157  /// address space can use this call to remap the section addresses for the
158  /// newly loaded object.
159  ///
160  /// For clients that do not need access to an ExecutionEngine instance this
161  /// method should be preferred to its cousin
162  /// MCJITMemoryManager::notifyObjectLoaded as this method is compatible with
163  /// ORC JIT stacks.
164  virtual void notifyObjectLoaded(RuntimeDyld &RTDyld,
165  const object::ObjectFile &Obj) {}
166 
167  private:
168  virtual void anchor();
169 
170  bool FinalizationLocked = false;
171  };
172 
173  /// \brief Construct a RuntimeDyld instance.
174  RuntimeDyld(MemoryManager &MemMgr, JITSymbolResolver &Resolver);
175  RuntimeDyld(const RuntimeDyld &) = delete;
176  RuntimeDyld &operator=(const RuntimeDyld &) = delete;
177  ~RuntimeDyld();
178 
179  /// Add the referenced object file to the list of objects to be loaded and
180  /// relocated.
181  std::unique_ptr<LoadedObjectInfo> loadObject(const object::ObjectFile &O);
182 
183  /// Get the address of our local copy of the symbol. This may or may not
184  /// be the address used for relocation (clients can copy the data around
185  /// and resolve relocatons based on where they put it).
186  void *getSymbolLocalAddress(StringRef Name) const;
187 
188  /// Get the target address and flags for the named symbol.
189  /// This address is the one used for relocation.
191 
192  /// Resolve the relocations for all symbols we currently know about.
193  void resolveRelocations();
194 
195  /// Map a section to its target address space value.
196  /// Map the address of a JIT section as returned from the memory manager
197  /// to the address in the target process as the running code will see it.
198  /// This is the address which will be used for relocation resolution.
199  void mapSectionAddress(const void *LocalAddress, uint64_t TargetAddress);
200 
201  /// Register any EH frame sections that have been loaded but not previously
202  /// registered with the memory manager. Note, RuntimeDyld is responsible
203  /// for identifying the EH frame and calling the memory manager with the
204  /// EH frame section data. However, the memory manager itself will handle
205  /// the actual target-specific EH frame registration.
206  void registerEHFrames();
207 
208  void deregisterEHFrames();
209 
210  bool hasError();
211  StringRef getErrorString();
212 
213  /// By default, only sections that are "required for execution" are passed to
214  /// the RTDyldMemoryManager, and other sections are discarded. Passing 'true'
215  /// to this method will cause RuntimeDyld to pass all sections to its
216  /// memory manager regardless of whether they are "required to execute" in the
217  /// usual sense. This is useful for inspecting metadata sections that may not
218  /// contain relocations, E.g. Debug info, stackmaps.
219  ///
220  /// Must be called before the first object file is loaded.
221  void setProcessAllSections(bool ProcessAllSections) {
222  assert(!Dyld && "setProcessAllSections must be called before loadObject.");
223  this->ProcessAllSections = ProcessAllSections;
224  }
225 
226  /// Perform all actions needed to make the code owned by this RuntimeDyld
227  /// instance executable:
228  ///
229  /// 1) Apply relocations.
230  /// 2) Register EH frames.
231  /// 3) Update memory permissions*.
232  ///
233  /// * Finalization is potentially recursive**, and the 3rd step will only be
234  /// applied by the outermost call to finalize. This allows different
235  /// RuntimeDyld instances to share a memory manager without the innermost
236  /// finalization locking the memory and causing relocation fixup errors in
237  /// outer instances.
238  ///
239  /// ** Recursive finalization occurs when one RuntimeDyld instances needs the
240  /// address of a symbol owned by some other instance in order to apply
241  /// relocations.
242  ///
243  void finalizeWithMemoryManagerLocking();
244 
245 private:
246  // RuntimeDyldImpl is the actual class. RuntimeDyld is just the public
247  // interface.
248  std::unique_ptr<RuntimeDyldImpl> Dyld;
249  MemoryManager &MemMgr;
250  JITSymbolResolver &Resolver;
251  bool ProcessAllSections;
252  RuntimeDyldCheckerImpl *Checker;
253 };
254 
255 } // end namespace llvm
256 
257 #endif // LLVM_EXECUTIONENGINE_RUNTIMEDYLD_H
virtual void reserveAllocationSpace(uintptr_t CodeSize, uint32_t CodeAlign, uintptr_t RODataSize, uint32_t RODataAlign, uintptr_t RWDataSize, uint32_t RWDataAlign)
Inform the memory manager about the total amount of memory required to allocate all sections to be lo...
Definition: RuntimeDyld.h:123
Information about the loaded object.
Definition: RuntimeDyld.h:69
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
This class is the base class for all object file types.
Definition: ObjectFile.h:189
Definition: BitVector.h:920
virtual bool needsToReserveAllocationSpace()
Override to return true to enable the reserveAllocationSpace callback.
Definition: RuntimeDyld.h:130
RuntimeDyldError(std::string ErrMsg)
Definition: RuntimeDyld.h:46
Expected< const typename ELFT::Sym * > getSymbol(typename ELFT::SymRange Symbols, uint32_t Index)
Definition: ELF.h:249
void setProcessAllSections(bool ProcessAllSections)
By default, only sections that are "required for execution" are passed to the RTDyldMemoryManager, and other sections are discarded.
Definition: RuntimeDyld.h:221
virtual void notifyObjectLoaded(RuntimeDyld &RTDyld, const object::ObjectFile &Obj)
This method is called after an object has been loaded into memory but before relocations are applied ...
Definition: RuntimeDyld.h:164
Symbol resolution.
Definition: JITSymbol.h:260
An inferface for inquiring the load address of a loaded object file to be used by the DIContext imple...
Definition: DIContext.h:211
Represents a symbol that has been evaluated to an address already.
Definition: JITSymbol.h:135
Base class for user error types.
Definition: Error.h:331
Base class for errors originating in RuntimeDyld, e.g.
Definition: RuntimeDyld.h:42
const std::string & getErrorMessage() const
Definition: RuntimeDyld.h:49
std::map< object::SectionRef, unsigned > ObjSectionToIDMap
Definition: RuntimeDyld.h:73
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
constexpr char Size[]
Key for Kernel::Arg::Metadata::mSize.
This class implements an extremely fast bulk output stream that can only output to a stream...
Definition: raw_ostream.h:44
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:49
LoadedObjectInfo(RuntimeDyldImpl &RTDyld, ObjSectionToIDMap ObjSecToIDMap)
Definition: RuntimeDyld.h:75
This is a value type class that represents a single section in the list of sections in the object fil...
Definition: ObjectFile.h:80