1 //===-- RuntimeDyld.h - Run-time dynamic linker for MC-JIT ------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // Interface for the runtime dynamic linker facilities of the MC-JIT.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_EXECUTIONENGINE_RUNTIMEDYLD_H
15 #define LLVM_EXECUTIONENGINE_RUNTIMEDYLD_H
17 #include "JITSymbolFlags.h"
18 #include "llvm/ADT/STLExtras.h"
19 #include "llvm/DebugInfo/DIContext.h"
20 #include "llvm/Object/ObjectFile.h"
21 #include "llvm/Support/Memory.h"
32 template <typename T> class OwningBinary;
35 /// Base class for errors originating in RuntimeDyld, e.g. missing relocation
37 class RuntimeDyldError : public ErrorInfo<RuntimeDyldError> {
40 RuntimeDyldError(std::string ErrMsg) : ErrMsg(std::move(ErrMsg)) {}
41 void log(raw_ostream &OS) const override;
42 const std::string &getErrorMessage() const { return ErrMsg; }
43 std::error_code convertToErrorCode() const override;
48 class RuntimeDyldImpl;
49 class RuntimeDyldCheckerImpl;
52 friend class RuntimeDyldCheckerImpl;
54 RuntimeDyld(const RuntimeDyld &) = delete;
55 void operator=(const RuntimeDyld &) = delete;
58 // Change the address associated with a section when resolving relocations.
59 // Any relocations already associated with the symbol will be re-resolved.
60 void reassignSectionAddress(unsigned SectionID, uint64_t Addr);
63 /// \brief Information about a named symbol.
64 class SymbolInfo : public JITSymbolBase {
66 SymbolInfo(std::nullptr_t) : JITSymbolBase(JITSymbolFlags::None), Address(0) {}
67 SymbolInfo(uint64_t Address, JITSymbolFlags Flags)
68 : JITSymbolBase(Flags), Address(Address) {}
69 explicit operator bool() const { return Address != 0; }
70 uint64_t getAddress() const { return Address; }
75 /// \brief Information about the loaded object.
76 class LoadedObjectInfo : public llvm::LoadedObjectInfo {
77 friend class RuntimeDyldImpl;
79 typedef std::map<object::SectionRef, unsigned> ObjSectionToIDMap;
81 LoadedObjectInfo(RuntimeDyldImpl &RTDyld, ObjSectionToIDMap ObjSecToIDMap)
82 : RTDyld(RTDyld), ObjSecToIDMap(std::move(ObjSecToIDMap)) {}
84 virtual object::OwningBinary<object::ObjectFile>
85 getObjectForDebug(const object::ObjectFile &Obj) const = 0;
88 getSectionLoadAddress(const object::SectionRef &Sec) const override;
91 virtual void anchor();
93 RuntimeDyldImpl &RTDyld;
94 ObjSectionToIDMap ObjSecToIDMap;
97 template <typename Derived> struct LoadedObjectInfoHelper : LoadedObjectInfo {
99 LoadedObjectInfoHelper(const LoadedObjectInfoHelper &) = default;
100 LoadedObjectInfoHelper() = default;
103 LoadedObjectInfoHelper(RuntimeDyldImpl &RTDyld,
104 LoadedObjectInfo::ObjSectionToIDMap ObjSecToIDMap)
105 : LoadedObjectInfo(RTDyld, std::move(ObjSecToIDMap)) {}
106 std::unique_ptr<llvm::LoadedObjectInfo> clone() const override {
107 return llvm::make_unique<Derived>(static_cast<const Derived &>(*this));
111 /// \brief Memory Management.
112 class MemoryManager {
113 friend class RuntimeDyld;
115 MemoryManager() : FinalizationLocked(false) {}
116 virtual ~MemoryManager() {}
118 /// Allocate a memory block of (at least) the given size suitable for
119 /// executable code. The SectionID is a unique identifier assigned by the
120 /// RuntimeDyld instance, and optionally recorded by the memory manager to
121 /// access a loaded section.
122 virtual uint8_t *allocateCodeSection(uintptr_t Size, unsigned Alignment,
124 StringRef SectionName) = 0;
126 /// Allocate a memory block of (at least) the given size suitable for data.
127 /// The SectionID is a unique identifier assigned by the JIT engine, and
128 /// optionally recorded by the memory manager to access a loaded section.
129 virtual uint8_t *allocateDataSection(uintptr_t Size, unsigned Alignment,
131 StringRef SectionName,
132 bool IsReadOnly) = 0;
134 /// Inform the memory manager about the total amount of memory required to
135 /// allocate all sections to be loaded:
136 /// \p CodeSize - the total size of all code sections
137 /// \p DataSizeRO - the total size of all read-only data sections
138 /// \p DataSizeRW - the total size of all read-write data sections
140 /// Note that by default the callback is disabled. To enable it
141 /// redefine the method needsToReserveAllocationSpace to return true.
142 virtual void reserveAllocationSpace(uintptr_t CodeSize, uint32_t CodeAlign,
143 uintptr_t RODataSize,
144 uint32_t RODataAlign,
145 uintptr_t RWDataSize,
146 uint32_t RWDataAlign) {}
148 /// Override to return true to enable the reserveAllocationSpace callback.
149 virtual bool needsToReserveAllocationSpace() { return false; }
151 /// Register the EH frames with the runtime so that c++ exceptions work.
153 /// \p Addr parameter provides the local address of the EH frame section
154 /// data, while \p LoadAddr provides the address of the data in the target
155 /// address space. If the section has not been remapped (which will usually
156 /// be the case for local execution) these two values will be the same.
157 virtual void registerEHFrames(uint8_t *Addr, uint64_t LoadAddr,
159 virtual void deregisterEHFrames(uint8_t *addr, uint64_t LoadAddr,
162 /// This method is called when object loading is complete and section page
163 /// permissions can be applied. It is up to the memory manager implementation
164 /// to decide whether or not to act on this method. The memory manager will
165 /// typically allocate all sections as read-write and then apply specific
166 /// permissions when this method is called. Code sections cannot be executed
167 /// until this function has been called. In addition, any cache coherency
168 /// operations needed to reliably use the memory are also performed.
170 /// Returns true if an error occurred, false otherwise.
171 virtual bool finalizeMemory(std::string *ErrMsg = nullptr) = 0;
173 /// This method is called after an object has been loaded into memory but
174 /// before relocations are applied to the loaded sections.
176 /// Memory managers which are preparing code for execution in an external
177 /// address space can use this call to remap the section addresses for the
178 /// newly loaded object.
180 /// For clients that do not need access to an ExecutionEngine instance this
181 /// method should be preferred to its cousin
182 /// MCJITMemoryManager::notifyObjectLoaded as this method is compatible with
184 virtual void notifyObjectLoaded(RuntimeDyld &RTDyld,
185 const object::ObjectFile &Obj) {}
188 virtual void anchor();
189 bool FinalizationLocked;
192 /// \brief Symbol resolution.
193 class SymbolResolver {
195 virtual ~SymbolResolver() {}
197 /// This method returns the address of the specified symbol if it exists
198 /// within the logical dynamic library represented by this
199 /// RTDyldMemoryManager. Unlike findSymbol, queries through this
200 /// interface should return addresses for hidden symbols.
202 /// This is of particular importance for the Orc JIT APIs, which support lazy
203 /// compilation by breaking up modules: Each of those broken out modules
204 /// must be able to resolve hidden symbols provided by the others. Clients
205 /// writing memory managers for MCJIT can usually ignore this method.
207 /// This method will be queried by RuntimeDyld when checking for previous
208 /// definitions of common symbols.
209 virtual SymbolInfo findSymbolInLogicalDylib(const std::string &Name) = 0;
211 /// This method returns the address of the specified function or variable.
212 /// It is used to resolve symbols during module linking.
214 /// If the returned symbol's address is equal to ~0ULL then RuntimeDyld will
215 /// skip all relocations for that symbol, and the client will be responsible
216 /// for handling them manually.
217 virtual SymbolInfo findSymbol(const std::string &Name) = 0;
220 virtual void anchor();
223 /// \brief Construct a RuntimeDyld instance.
224 RuntimeDyld(MemoryManager &MemMgr, SymbolResolver &Resolver);
227 /// Add the referenced object file to the list of objects to be loaded and
229 std::unique_ptr<LoadedObjectInfo> loadObject(const object::ObjectFile &O);
231 /// Get the address of our local copy of the symbol. This may or may not
232 /// be the address used for relocation (clients can copy the data around
233 /// and resolve relocatons based on where they put it).
234 void *getSymbolLocalAddress(StringRef Name) const;
236 /// Get the target address and flags for the named symbol.
237 /// This address is the one used for relocation.
238 SymbolInfo getSymbol(StringRef Name) const;
240 /// Resolve the relocations for all symbols we currently know about.
241 void resolveRelocations();
243 /// Map a section to its target address space value.
244 /// Map the address of a JIT section as returned from the memory manager
245 /// to the address in the target process as the running code will see it.
246 /// This is the address which will be used for relocation resolution.
247 void mapSectionAddress(const void *LocalAddress, uint64_t TargetAddress);
249 /// Register any EH frame sections that have been loaded but not previously
250 /// registered with the memory manager. Note, RuntimeDyld is responsible
251 /// for identifying the EH frame and calling the memory manager with the
252 /// EH frame section data. However, the memory manager itself will handle
253 /// the actual target-specific EH frame registration.
254 void registerEHFrames();
256 void deregisterEHFrames();
259 StringRef getErrorString();
261 /// By default, only sections that are "required for execution" are passed to
262 /// the RTDyldMemoryManager, and other sections are discarded. Passing 'true'
263 /// to this method will cause RuntimeDyld to pass all sections to its
264 /// memory manager regardless of whether they are "required to execute" in the
265 /// usual sense. This is useful for inspecting metadata sections that may not
266 /// contain relocations, E.g. Debug info, stackmaps.
268 /// Must be called before the first object file is loaded.
269 void setProcessAllSections(bool ProcessAllSections) {
270 assert(!Dyld && "setProcessAllSections must be called before loadObject.");
271 this->ProcessAllSections = ProcessAllSections;
274 /// Perform all actions needed to make the code owned by this RuntimeDyld
275 /// instance executable:
277 /// 1) Apply relocations.
278 /// 2) Register EH frames.
279 /// 3) Update memory permissions*.
281 /// * Finalization is potentially recursive**, and the 3rd step will only be
282 /// applied by the outermost call to finalize. This allows different
283 /// RuntimeDyld instances to share a memory manager without the innermost
284 /// finalization locking the memory and causing relocation fixup errors in
287 /// ** Recursive finalization occurs when one RuntimeDyld instances needs the
288 /// address of a symbol owned by some other instance in order to apply
291 void finalizeWithMemoryManagerLocking();
294 // RuntimeDyldImpl is the actual class. RuntimeDyld is just the public
296 std::unique_ptr<RuntimeDyldImpl> Dyld;
297 MemoryManager &MemMgr;
298 SymbolResolver &Resolver;
299 bool ProcessAllSections;
300 RuntimeDyldCheckerImpl *Checker;
303 } // end namespace llvm
305 #endif // LLVM_EXECUTIONENGINE_RUNTIMEDYLD_H