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RuntimeDyld.h
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1 //===- RuntimeDyld.h - Run-time dynamic linker for MC-JIT -------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // Interface for the runtime dynamic linker facilities of the MC-JIT.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_EXECUTIONENGINE_RUNTIMEDYLD_H
14 #define LLVM_EXECUTIONENGINE_RUNTIMEDYLD_H
15 
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 
56 class RuntimeDyldImpl;
57 
58 class RuntimeDyld {
59 protected:
60  // Change the address associated with a section when resolving relocations.
61  // Any relocations already associated with the symbol will be re-resolved.
62  void reassignSectionAddress(unsigned SectionID, uint64_t Addr);
63 
64 public:
67  unsigned SectionID, uint32_t StubOffset)>;
68 
69  /// Information about the loaded object.
71  friend class RuntimeDyldImpl;
72 
73  public:
74  using ObjSectionToIDMap = std::map<object::SectionRef, unsigned>;
75 
77  : RTDyld(RTDyld), ObjSecToIDMap(std::move(ObjSecToIDMap)) {}
78 
80  getObjectForDebug(const object::ObjectFile &Obj) const = 0;
81 
82  uint64_t
83  getSectionLoadAddress(const object::SectionRef &Sec) const override;
84 
85  protected:
86  virtual void anchor();
87 
90  };
91 
92  /// Memory Management.
93  class MemoryManager {
94  friend class RuntimeDyld;
95 
96  public:
97  MemoryManager() = default;
98  virtual ~MemoryManager() = default;
99 
100  /// Allocate a memory block of (at least) the given size suitable for
101  /// executable code. The SectionID is a unique identifier assigned by the
102  /// RuntimeDyld instance, and optionally recorded by the memory manager to
103  /// access a loaded section.
104  virtual uint8_t *allocateCodeSection(uintptr_t Size, unsigned Alignment,
105  unsigned SectionID,
106  StringRef SectionName) = 0;
107 
108  /// Allocate a memory block of (at least) the given size suitable for data.
109  /// The SectionID is a unique identifier assigned by the JIT engine, and
110  /// optionally recorded by the memory manager to access a loaded section.
111  virtual uint8_t *allocateDataSection(uintptr_t Size, unsigned Alignment,
112  unsigned SectionID,
114  bool IsReadOnly) = 0;
115 
116  /// Inform the memory manager about the total amount of memory required to
117  /// allocate all sections to be loaded:
118  /// \p CodeSize - the total size of all code sections
119  /// \p DataSizeRO - the total size of all read-only data sections
120  /// \p DataSizeRW - the total size of all read-write data sections
121  ///
122  /// Note that by default the callback is disabled. To enable it
123  /// redefine the method needsToReserveAllocationSpace to return true.
124  virtual void reserveAllocationSpace(uintptr_t CodeSize, uint32_t CodeAlign,
125  uintptr_t RODataSize,
126  uint32_t RODataAlign,
127  uintptr_t RWDataSize,
128  uint32_t RWDataAlign) {}
129 
130  /// Override to return true to enable the reserveAllocationSpace callback.
131  virtual bool needsToReserveAllocationSpace() { return false; }
132 
133  /// Register the EH frames with the runtime so that c++ exceptions work.
134  ///
135  /// \p Addr parameter provides the local address of the EH frame section
136  /// data, while \p LoadAddr provides the address of the data in the target
137  /// address space. If the section has not been remapped (which will usually
138  /// be the case for local execution) these two values will be the same.
139  virtual void registerEHFrames(uint8_t *Addr, uint64_t LoadAddr,
140  size_t Size) = 0;
141  virtual void deregisterEHFrames() = 0;
142 
143  /// This method is called when object loading is complete and section page
144  /// permissions can be applied. It is up to the memory manager implementation
145  /// to decide whether or not to act on this method. The memory manager will
146  /// typically allocate all sections as read-write and then apply specific
147  /// permissions when this method is called. Code sections cannot be executed
148  /// until this function has been called. In addition, any cache coherency
149  /// operations needed to reliably use the memory are also performed.
150  ///
151  /// Returns true if an error occurred, false otherwise.
152  virtual bool finalizeMemory(std::string *ErrMsg = nullptr) = 0;
153 
154  /// This method is called after an object has been loaded into memory but
155  /// before relocations are applied to the loaded sections.
156  ///
157  /// Memory managers which are preparing code for execution in an external
158  /// address space can use this call to remap the section addresses for the
159  /// newly loaded object.
160  ///
161  /// For clients that do not need access to an ExecutionEngine instance this
162  /// method should be preferred to its cousin
163  /// MCJITMemoryManager::notifyObjectLoaded as this method is compatible with
164  /// ORC JIT stacks.
165  virtual void notifyObjectLoaded(RuntimeDyld &RTDyld,
166  const object::ObjectFile &Obj) {}
167 
168  private:
169  virtual void anchor();
170 
171  bool FinalizationLocked = false;
172  };
173 
174  /// Construct a RuntimeDyld instance.
176  RuntimeDyld(const RuntimeDyld &) = delete;
177  RuntimeDyld &operator=(const RuntimeDyld &) = delete;
178  ~RuntimeDyld();
179 
180  /// Add the referenced object file to the list of objects to be loaded and
181  /// relocated.
182  std::unique_ptr<LoadedObjectInfo> loadObject(const object::ObjectFile &O);
183 
184  /// Get the address of our local copy of the symbol. This may or may not
185  /// be the address used for relocation (clients can copy the data around
186  /// and resolve relocatons based on where they put it).
187  void *getSymbolLocalAddress(StringRef Name) const;
188 
189  /// Get the section ID for the section containing the given symbol.
190  unsigned getSymbolSectionID(StringRef Name) const;
191 
192  /// Get the target address and flags for the named symbol.
193  /// This address is the one used for relocation.
194  JITEvaluatedSymbol getSymbol(StringRef Name) const;
195 
196  /// Returns a copy of the symbol table. This can be used by on-finalized
197  /// callbacks to extract the symbol table before throwing away the
198  /// RuntimeDyld instance. Because the map keys (StringRefs) are backed by
199  /// strings inside the RuntimeDyld instance, the map should be processed
200  /// before the RuntimeDyld instance is discarded.
201  std::map<StringRef, JITEvaluatedSymbol> getSymbolTable() const;
202 
203  /// Resolve the relocations for all symbols we currently know about.
204  void resolveRelocations();
205 
206  /// Map a section to its target address space value.
207  /// Map the address of a JIT section as returned from the memory manager
208  /// to the address in the target process as the running code will see it.
209  /// This is the address which will be used for relocation resolution.
210  void mapSectionAddress(const void *LocalAddress, uint64_t TargetAddress);
211 
212  /// Returns the section's working memory.
213  StringRef getSectionContent(unsigned SectionID) const;
214 
215  /// If the section was loaded, return the section's load address,
216  /// otherwise return None.
217  uint64_t getSectionLoadAddress(unsigned SectionID) const;
218 
219  /// Set the NotifyStubEmitted callback. This is used for debugging
220  /// purposes. A callback is made for each stub that is generated.
222  this->NotifyStubEmitted = std::move(NotifyStubEmitted);
223  }
224 
225  /// Register any EH frame sections that have been loaded but not previously
226  /// registered with the memory manager. Note, RuntimeDyld is responsible
227  /// for identifying the EH frame and calling the memory manager with the
228  /// EH frame section data. However, the memory manager itself will handle
229  /// the actual target-specific EH frame registration.
230  void registerEHFrames();
231 
232  void deregisterEHFrames();
233 
234  bool hasError();
235  StringRef getErrorString();
236 
237  /// By default, only sections that are "required for execution" are passed to
238  /// the RTDyldMemoryManager, and other sections are discarded. Passing 'true'
239  /// to this method will cause RuntimeDyld to pass all sections to its
240  /// memory manager regardless of whether they are "required to execute" in the
241  /// usual sense. This is useful for inspecting metadata sections that may not
242  /// contain relocations, E.g. Debug info, stackmaps.
243  ///
244  /// Must be called before the first object file is loaded.
245  void setProcessAllSections(bool ProcessAllSections) {
246  assert(!Dyld && "setProcessAllSections must be called before loadObject.");
247  this->ProcessAllSections = ProcessAllSections;
248  }
249 
250  /// Perform all actions needed to make the code owned by this RuntimeDyld
251  /// instance executable:
252  ///
253  /// 1) Apply relocations.
254  /// 2) Register EH frames.
255  /// 3) Update memory permissions*.
256  ///
257  /// * Finalization is potentially recursive**, and the 3rd step will only be
258  /// applied by the outermost call to finalize. This allows different
259  /// RuntimeDyld instances to share a memory manager without the innermost
260  /// finalization locking the memory and causing relocation fixup errors in
261  /// outer instances.
262  ///
263  /// ** Recursive finalization occurs when one RuntimeDyld instances needs the
264  /// address of a symbol owned by some other instance in order to apply
265  /// relocations.
266  ///
267  void finalizeWithMemoryManagerLocking();
268 
269 private:
270  friend void
272  std::unique_ptr<MemoryBuffer> UnderlyingBuffer,
274  bool ProcessAllSections,
275  unique_function<Error(std::unique_ptr<LoadedObjectInfo>,
276  std::map<StringRef, JITEvaluatedSymbol>)>
277  OnLoaded,
278  unique_function<void(Error)> OnEmitted);
279 
280  // RuntimeDyldImpl is the actual class. RuntimeDyld is just the public
281  // interface.
282  std::unique_ptr<RuntimeDyldImpl> Dyld;
283  MemoryManager &MemMgr;
284  JITSymbolResolver &Resolver;
285  bool ProcessAllSections;
286  NotifyStubEmittedFunction NotifyStubEmitted;
287 };
288 
289 // Asynchronous JIT link for ORC.
290 //
291 // Warning: This API is experimental and probably should not be used by anyone
292 // but ORC's RTDyldObjectLinkingLayer2. Internally it constructs a RuntimeDyld
293 // instance and uses continuation passing to perform the fix-up and finalize
294 // steps asynchronously.
295 void jitLinkForORC(
296  object::ObjectFile &Obj, std::unique_ptr<MemoryBuffer> UnderlyingBuffer,
298  bool ProcessAllSections,
299  unique_function<Error(std::unique_ptr<RuntimeDyld::LoadedObjectInfo>,
300  std::map<StringRef, JITEvaluatedSymbol>)>
301  OnLoaded,
302  unique_function<void(Error)> OnEmitted);
303 
304 } // end namespace llvm
305 
306 #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:124
Information about the loaded object.
Definition: RuntimeDyld.h:70
This class represents lattice values for constants.
Definition: AllocatorList.h:23
amdgpu Simplify well known AMD library false FunctionCallee Value const Twine & Name
void jitLinkForORC(object::ObjectFile &Obj, std::unique_ptr< MemoryBuffer > UnderlyingBuffer, RuntimeDyld::MemoryManager &MemMgr, JITSymbolResolver &Resolver, bool ProcessAllSections, unique_function< Error(std::unique_ptr< RuntimeDyld::LoadedObjectInfo >, std::map< StringRef, JITEvaluatedSymbol >)> OnLoaded, unique_function< void(Error)> OnEmitted)
This class is the base class for all object file types.
Definition: ObjectFile.h:221
static unsigned getSymbolSectionID(const ObjectFile &O, SymbolRef Sym)
Definition: SymbolSize.cpp:33
void setNotifyStubEmitted(NotifyStubEmittedFunction NotifyStubEmitted)
Set the NotifyStubEmitted callback.
Definition: RuntimeDyld.h:221
Definition: BitVector.h:937
constexpr char SymbolName[]
Key for Kernel::Metadata::mSymbolName.
virtual bool needsToReserveAllocationSpace()
Override to return true to enable the reserveAllocationSpace callback.
Definition: RuntimeDyld.h:131
std::function< void(StringRef FileName, StringRef SectionName, StringRef SymbolName, unsigned SectionID, uint32_t StubOffset)> NotifyStubEmittedFunction
Definition: RuntimeDyld.h:67
RuntimeDyldError(std::string ErrMsg)
Definition: RuntimeDyld.h:46
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:245
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:165
Interface for looking up the initializer for a variable name, used by Init::resolveReferences.
Definition: Record.h:1863
Symbol resolution interface.
Definition: JITSymbol.h:325
An inferface for inquiring the load address of a loaded object file to be used by the DIContext imple...
Definition: DIContext.h:243
Represents a symbol that has been evaluated to an address already.
Definition: JITSymbol.h:190
Base class for user error types.
Definition: Error.h:344
Base class for errors originating in RuntimeDyld, e.g.
Definition: RuntimeDyld.h:42
uint32_t Size
Definition: Profile.cpp:46
const std::string & getErrorMessage() const
Definition: RuntimeDyld.h:49
std::map< object::SectionRef, unsigned > ObjSectionToIDMap
Definition: RuntimeDyld.h:74
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
This file provides a collection of function (or more generally, callable) type erasure utilities supp...
Lightweight error class with error context and mandatory checking.
Definition: Error.h:157
This class implements an extremely fast bulk output stream that can only output to a stream...
Definition: raw_ostream.h:45
print Print MemDeps of function
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:48
LoadedObjectInfo(RuntimeDyldImpl &RTDyld, ObjSectionToIDMap ObjSecToIDMap)
Definition: RuntimeDyld.h:76
This is a value type class that represents a single section in the list of sections in the object fil...
Definition: ObjectFile.h:81