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