MCJIT.h revision dce4a407a24b04eebc6a376f8e62b41aaa7b071f 
1//===-- MCJIT.h - Class definition for the MCJIT ----------------*- 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#ifndef LLVM_LIB_EXECUTIONENGINE_MCJIT_H
11#define LLVM_LIB_EXECUTIONENGINE_MCJIT_H
12
13#include "llvm/ADT/DenseMap.h"
14#include "llvm/ADT/SmallPtrSet.h"
15#include "llvm/ADT/SmallVector.h"
16#include "llvm/ExecutionEngine/ExecutionEngine.h"
17#include "llvm/ExecutionEngine/ObjectCache.h"
18#include "llvm/ExecutionEngine/ObjectImage.h"
19#include "llvm/ExecutionEngine/RuntimeDyld.h"
20#include "llvm/IR/Module.h"
21
22namespace llvm {
23class MCJIT;
24
25// This is a helper class that the MCJIT execution engine uses for linking
26// functions across modules that it owns.  It aggregates the memory manager
27// that is passed in to the MCJIT constructor and defers most functionality
28// to that object.
29class LinkingMemoryManager : public RTDyldMemoryManager {
30public:
31  LinkingMemoryManager(MCJIT *Parent, RTDyldMemoryManager *MM)
32    : ParentEngine(Parent), ClientMM(MM) {}
33
34  uint64_t getSymbolAddress(const std::string &Name) override;
35
36  // Functions deferred to client memory manager
37  uint8_t *allocateCodeSection(uintptr_t Size, unsigned Alignment,
38                               unsigned SectionID,
39                               StringRef SectionName) override {
40    return ClientMM->allocateCodeSection(Size, Alignment, SectionID, SectionName);
41  }
42
43  uint8_t *allocateDataSection(uintptr_t Size, unsigned Alignment,
44                               unsigned SectionID, StringRef SectionName,
45                               bool IsReadOnly) override {
46    return ClientMM->allocateDataSection(Size, Alignment,
47                                         SectionID, SectionName, IsReadOnly);
48  }
49
50  void reserveAllocationSpace(uintptr_t CodeSize, uintptr_t DataSizeRO,
51                              uintptr_t DataSizeRW) override {
52    return ClientMM->reserveAllocationSpace(CodeSize, DataSizeRO, DataSizeRW);
53  }
54
55  bool needsToReserveAllocationSpace() override {
56    return ClientMM->needsToReserveAllocationSpace();
57  }
58
59  void notifyObjectLoaded(ExecutionEngine *EE,
60                          const ObjectImage *Obj) override {
61    ClientMM->notifyObjectLoaded(EE, Obj);
62  }
63
64  void registerEHFrames(uint8_t *Addr, uint64_t LoadAddr,
65                        size_t Size) override {
66    ClientMM->registerEHFrames(Addr, LoadAddr, Size);
67  }
68
69  void deregisterEHFrames(uint8_t *Addr, uint64_t LoadAddr,
70                          size_t Size) override {
71    ClientMM->deregisterEHFrames(Addr, LoadAddr, Size);
72  }
73
74  bool finalizeMemory(std::string *ErrMsg = nullptr) override {
75    return ClientMM->finalizeMemory(ErrMsg);
76  }
77
78private:
79  MCJIT *ParentEngine;
80  std::unique_ptr<RTDyldMemoryManager> ClientMM;
81};
82
83// About Module states: added->loaded->finalized.
84//
85// The purpose of the "added" state is having modules in standby. (added=known
86// but not compiled). The idea is that you can add a module to provide function
87// definitions but if nothing in that module is referenced by a module in which
88// a function is executed (note the wording here because it's not exactly the
89// ideal case) then the module never gets compiled. This is sort of lazy
90// compilation.
91//
92// The purpose of the "loaded" state (loaded=compiled and required sections
93// copied into local memory but not yet ready for execution) is to have an
94// intermediate state wherein clients can remap the addresses of sections, using
95// MCJIT::mapSectionAddress, (in preparation for later copying to a new location
96// or an external process) before relocations and page permissions are applied.
97//
98// It might not be obvious at first glance, but the "remote-mcjit" case in the
99// lli tool does this.  In that case, the intermediate action is taken by the
100// RemoteMemoryManager in response to the notifyObjectLoaded function being
101// called.
102
103class MCJIT : public ExecutionEngine {
104  MCJIT(Module *M, TargetMachine *tm, RTDyldMemoryManager *MemMgr,
105        bool AllocateGVsWithCode);
106
107  typedef llvm::SmallPtrSet<Module *, 4> ModulePtrSet;
108
109  class OwningModuleContainer {
110  public:
111    OwningModuleContainer() {
112    }
113    ~OwningModuleContainer() {
114      freeModulePtrSet(AddedModules);
115      freeModulePtrSet(LoadedModules);
116      freeModulePtrSet(FinalizedModules);
117    }
118
119    ModulePtrSet::iterator begin_added() { return AddedModules.begin(); }
120    ModulePtrSet::iterator end_added() { return AddedModules.end(); }
121
122    ModulePtrSet::iterator begin_loaded() { return LoadedModules.begin(); }
123    ModulePtrSet::iterator end_loaded() { return LoadedModules.end(); }
124
125    ModulePtrSet::iterator begin_finalized() { return FinalizedModules.begin(); }
126    ModulePtrSet::iterator end_finalized() { return FinalizedModules.end(); }
127
128    void addModule(Module *M) {
129      AddedModules.insert(M);
130    }
131
132    bool removeModule(Module *M) {
133      return AddedModules.erase(M) || LoadedModules.erase(M) ||
134             FinalizedModules.erase(M);
135    }
136
137    bool hasModuleBeenAddedButNotLoaded(Module *M) {
138      return AddedModules.count(M) != 0;
139    }
140
141    bool hasModuleBeenLoaded(Module *M) {
142      // If the module is in either the "loaded" or "finalized" sections it
143      // has been loaded.
144      return (LoadedModules.count(M) != 0 ) || (FinalizedModules.count(M) != 0);
145    }
146
147    bool hasModuleBeenFinalized(Module *M) {
148      return FinalizedModules.count(M) != 0;
149    }
150
151    bool ownsModule(Module* M) {
152      return (AddedModules.count(M) != 0) || (LoadedModules.count(M) != 0) ||
153             (FinalizedModules.count(M) != 0);
154    }
155
156    void markModuleAsLoaded(Module *M) {
157      // This checks against logic errors in the MCJIT implementation.
158      // This function should never be called with either a Module that MCJIT
159      // does not own or a Module that has already been loaded and/or finalized.
160      assert(AddedModules.count(M) &&
161             "markModuleAsLoaded: Module not found in AddedModules");
162
163      // Remove the module from the "Added" set.
164      AddedModules.erase(M);
165
166      // Add the Module to the "Loaded" set.
167      LoadedModules.insert(M);
168    }
169
170    void markModuleAsFinalized(Module *M) {
171      // This checks against logic errors in the MCJIT implementation.
172      // This function should never be called with either a Module that MCJIT
173      // does not own, a Module that has not been loaded or a Module that has
174      // already been finalized.
175      assert(LoadedModules.count(M) &&
176             "markModuleAsFinalized: Module not found in LoadedModules");
177
178      // Remove the module from the "Loaded" section of the list.
179      LoadedModules.erase(M);
180
181      // Add the Module to the "Finalized" section of the list by inserting it
182      // before the 'end' iterator.
183      FinalizedModules.insert(M);
184    }
185
186    void markAllLoadedModulesAsFinalized() {
187      for (ModulePtrSet::iterator I = LoadedModules.begin(),
188                                  E = LoadedModules.end();
189           I != E; ++I) {
190        Module *M = *I;
191        FinalizedModules.insert(M);
192      }
193      LoadedModules.clear();
194    }
195
196  private:
197    ModulePtrSet AddedModules;
198    ModulePtrSet LoadedModules;
199    ModulePtrSet FinalizedModules;
200
201    void freeModulePtrSet(ModulePtrSet& MPS) {
202      // Go through the module set and delete everything.
203      for (ModulePtrSet::iterator I = MPS.begin(), E = MPS.end(); I != E; ++I) {
204        Module *M = *I;
205        delete M;
206      }
207      MPS.clear();
208    }
209  };
210
211  TargetMachine *TM;
212  MCContext *Ctx;
213  LinkingMemoryManager MemMgr;
214  RuntimeDyld Dyld;
215  SmallVector<JITEventListener*, 2> EventListeners;
216
217  OwningModuleContainer OwnedModules;
218
219  SmallVector<object::Archive*, 2> Archives;
220
221  typedef SmallVector<ObjectImage *, 2> LoadedObjectList;
222  LoadedObjectList  LoadedObjects;
223
224  // An optional ObjectCache to be notified of compiled objects and used to
225  // perform lookup of pre-compiled code to avoid re-compilation.
226  ObjectCache *ObjCache;
227
228  Function *FindFunctionNamedInModulePtrSet(const char *FnName,
229                                            ModulePtrSet::iterator I,
230                                            ModulePtrSet::iterator E);
231
232  void runStaticConstructorsDestructorsInModulePtrSet(bool isDtors,
233                                                      ModulePtrSet::iterator I,
234                                                      ModulePtrSet::iterator E);
235
236public:
237  ~MCJIT();
238
239  /// @name ExecutionEngine interface implementation
240  /// @{
241  void addModule(Module *M) override;
242  void addObjectFile(std::unique_ptr<object::ObjectFile> O) override;
243  void addArchive(object::Archive *O) override;
244  bool removeModule(Module *M) override;
245
246  /// FindFunctionNamed - Search all of the active modules to find the one that
247  /// defines FnName.  This is very slow operation and shouldn't be used for
248  /// general code.
249  Function *FindFunctionNamed(const char *FnName) override;
250
251  /// Sets the object manager that MCJIT should use to avoid compilation.
252  void setObjectCache(ObjectCache *manager) override;
253
254  void setProcessAllSections(bool ProcessAllSections) override {
255    Dyld.setProcessAllSections(ProcessAllSections);
256  }
257
258  void generateCodeForModule(Module *M) override;
259
260  /// finalizeObject - ensure the module is fully processed and is usable.
261  ///
262  /// It is the user-level function for completing the process of making the
263  /// object usable for execution. It should be called after sections within an
264  /// object have been relocated using mapSectionAddress.  When this method is
265  /// called the MCJIT execution engine will reapply relocations for a loaded
266  /// object.
267  /// Is it OK to finalize a set of modules, add modules and finalize again.
268  // FIXME: Do we really need both of these?
269  void finalizeObject() override;
270  virtual void finalizeModule(Module *);
271  void finalizeLoadedModules();
272
273  /// runStaticConstructorsDestructors - This method is used to execute all of
274  /// the static constructors or destructors for a program.
275  ///
276  /// \param isDtors - Run the destructors instead of constructors.
277  void runStaticConstructorsDestructors(bool isDtors) override;
278
279  void *getPointerToBasicBlock(BasicBlock *BB) override;
280
281  void *getPointerToFunction(Function *F) override;
282
283  void *recompileAndRelinkFunction(Function *F) override;
284
285  void freeMachineCodeForFunction(Function *F) override;
286
287  GenericValue runFunction(Function *F,
288                           const std::vector<GenericValue> &ArgValues) override;
289
290  /// getPointerToNamedFunction - This method returns the address of the
291  /// specified function by using the dlsym function call.  As such it is only
292  /// useful for resolving library symbols, not code generated symbols.
293  ///
294  /// If AbortOnFailure is false and no function with the given name is
295  /// found, this function silently returns a null pointer. Otherwise,
296  /// it prints a message to stderr and aborts.
297  ///
298  void *getPointerToNamedFunction(const std::string &Name,
299                                  bool AbortOnFailure = true) override;
300
301  /// mapSectionAddress - map a section to its target address space value.
302  /// Map the address of a JIT section as returned from the memory manager
303  /// to the address in the target process as the running code will see it.
304  /// This is the address which will be used for relocation resolution.
305  void mapSectionAddress(const void *LocalAddress,
306                         uint64_t TargetAddress) override {
307    Dyld.mapSectionAddress(LocalAddress, TargetAddress);
308  }
309  void RegisterJITEventListener(JITEventListener *L) override;
310  void UnregisterJITEventListener(JITEventListener *L) override;
311
312  // If successful, these function will implicitly finalize all loaded objects.
313  // To get a function address within MCJIT without causing a finalize, use
314  // getSymbolAddress.
315  uint64_t getGlobalValueAddress(const std::string &Name) override;
316  uint64_t getFunctionAddress(const std::string &Name) override;
317
318  TargetMachine *getTargetMachine() override { return TM; }
319
320  /// @}
321  /// @name (Private) Registration Interfaces
322  /// @{
323
324  static void Register() {
325    MCJITCtor = createJIT;
326  }
327
328  static ExecutionEngine *createJIT(Module *M,
329                                    std::string *ErrorStr,
330                                    RTDyldMemoryManager *MemMgr,
331                                    bool GVsWithCode,
332                                    TargetMachine *TM);
333
334  // @}
335
336  // This is not directly exposed via the ExecutionEngine API, but it is
337  // used by the LinkingMemoryManager.
338  uint64_t getSymbolAddress(const std::string &Name,
339                          bool CheckFunctionsOnly);
340
341protected:
342  /// emitObject -- Generate a JITed object in memory from the specified module
343  /// Currently, MCJIT only supports a single module and the module passed to
344  /// this function call is expected to be the contained module.  The module
345  /// is passed as a parameter here to prepare for multiple module support in
346  /// the future.
347  ObjectBufferStream* emitObject(Module *M);
348
349  void NotifyObjectEmitted(const ObjectImage& Obj);
350  void NotifyFreeingObject(const ObjectImage& Obj);
351
352  uint64_t getExistingSymbolAddress(const std::string &Name);
353  Module *findModuleForSymbol(const std::string &Name,
354                              bool CheckFunctionsOnly);
355};
356
357} // End llvm namespace
358
359#endif
360