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/ADT/StringRef.h"
20 #include "llvm/Object/ObjectFile.h"
21 #include "llvm/Support/Memory.h"
22 #include "llvm/DebugInfo/DIContext.h"
30 template <typename T> class OwningBinary;
33 class RuntimeDyldImpl;
34 class RuntimeDyldCheckerImpl;
37 friend class RuntimeDyldCheckerImpl;
39 RuntimeDyld(const RuntimeDyld &) = delete;
40 void operator=(const RuntimeDyld &) = delete;
43 // Change the address associated with a section when resolving relocations.
44 // Any relocations already associated with the symbol will be re-resolved.
45 void reassignSectionAddress(unsigned SectionID, uint64_t Addr);
48 /// \brief Information about a named symbol.
49 class SymbolInfo : public JITSymbolBase {
51 SymbolInfo(std::nullptr_t) : JITSymbolBase(JITSymbolFlags::None), Address(0) {}
52 SymbolInfo(uint64_t Address, JITSymbolFlags Flags)
53 : JITSymbolBase(Flags), Address(Address) {}
54 explicit operator bool() const { return Address != 0; }
55 uint64_t getAddress() const { return Address; }
60 /// \brief Information about the loaded object.
61 class LoadedObjectInfo : public llvm::LoadedObjectInfo {
62 friend class RuntimeDyldImpl;
64 typedef std::map<object::SectionRef, unsigned> ObjSectionToIDMap;
66 LoadedObjectInfo(RuntimeDyldImpl &RTDyld, ObjSectionToIDMap ObjSecToIDMap)
67 : RTDyld(RTDyld), ObjSecToIDMap(ObjSecToIDMap) { }
69 virtual object::OwningBinary<object::ObjectFile>
70 getObjectForDebug(const object::ObjectFile &Obj) const = 0;
73 getSectionLoadAddress(const object::SectionRef &Sec) const override;
76 virtual void anchor();
78 RuntimeDyldImpl &RTDyld;
79 ObjSectionToIDMap ObjSecToIDMap;
82 template <typename Derived> struct LoadedObjectInfoHelper : LoadedObjectInfo {
84 LoadedObjectInfoHelper(const LoadedObjectInfoHelper &) = default;
85 LoadedObjectInfoHelper() = default;
88 LoadedObjectInfoHelper(RuntimeDyldImpl &RTDyld,
89 LoadedObjectInfo::ObjSectionToIDMap ObjSecToIDMap)
90 : LoadedObjectInfo(RTDyld, std::move(ObjSecToIDMap)) {}
91 std::unique_ptr<llvm::LoadedObjectInfo> clone() const override {
92 return llvm::make_unique<Derived>(static_cast<const Derived &>(*this));
96 /// \brief Memory Management.
99 virtual ~MemoryManager() {}
101 /// Allocate a memory block of (at least) the given size suitable for
102 /// executable code. The SectionID is a unique identifier assigned by the
103 /// RuntimeDyld instance, and optionally recorded by the memory manager to
104 /// access a loaded section.
105 virtual uint8_t *allocateCodeSection(uintptr_t Size, unsigned Alignment,
107 StringRef SectionName) = 0;
109 /// Allocate a memory block of (at least) the given size suitable for data.
110 /// The SectionID is a unique identifier assigned by the JIT engine, and
111 /// optionally recorded by the memory manager to access a loaded section.
112 virtual uint8_t *allocateDataSection(uintptr_t Size, unsigned Alignment,
114 StringRef SectionName,
115 bool IsReadOnly) = 0;
117 /// Inform the memory manager about the total amount of memory required to
118 /// allocate all sections to be loaded:
119 /// \p CodeSize - the total size of all code sections
120 /// \p DataSizeRO - the total size of all read-only data sections
121 /// \p DataSizeRW - the total size of all read-write data sections
123 /// Note that by default the callback is disabled. To enable it
124 /// redefine the method needsToReserveAllocationSpace to return true.
125 virtual void reserveAllocationSpace(uintptr_t CodeSize,
126 uintptr_t DataSizeRO,
127 uintptr_t DataSizeRW) {}
129 /// Override to return true to enable the reserveAllocationSpace callback.
130 virtual bool needsToReserveAllocationSpace() { return false; }
132 /// Register the EH frames with the runtime so that c++ exceptions work.
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,
140 virtual void deregisterEHFrames(uint8_t *addr, uint64_t LoadAddr,
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.
151 /// Returns true if an error occurred, false otherwise.
152 virtual bool finalizeMemory(std::string *ErrMsg = nullptr) = 0;
155 virtual void anchor();
158 /// \brief Symbol resolution.
159 class SymbolResolver {
161 virtual ~SymbolResolver() {}
163 /// This method returns the address of the specified function or variable.
164 /// It is used to resolve symbols during module linking.
166 /// If the returned symbol's address is equal to ~0ULL then RuntimeDyld will
167 /// skip all relocations for that symbol, and the client will be responsible
168 /// for handling them manually.
169 virtual SymbolInfo findSymbol(const std::string &Name) = 0;
171 /// This method returns the address of the specified symbol if it exists
172 /// within the logical dynamic library represented by this
173 /// RTDyldMemoryManager. Unlike getSymbolAddress, queries through this
174 /// interface should return addresses for hidden symbols.
176 /// This is of particular importance for the Orc JIT APIs, which support lazy
177 /// compilation by breaking up modules: Each of those broken out modules
178 /// must be able to resolve hidden symbols provided by the others. Clients
179 /// writing memory managers for MCJIT can usually ignore this method.
181 /// This method will be queried by RuntimeDyld when checking for previous
182 /// definitions of common symbols. It will *not* be queried by default when
183 /// resolving external symbols (this minimises the link-time overhead for
184 /// MCJIT clients who don't care about Orc features). If you are writing a
185 /// RTDyldMemoryManager for Orc and want "external" symbol resolution to
186 /// search the logical dylib, you should override your getSymbolAddress
187 /// method call this method directly.
188 virtual SymbolInfo findSymbolInLogicalDylib(const std::string &Name) = 0;
190 virtual void anchor();
193 /// \brief Construct a RuntimeDyld instance.
194 RuntimeDyld(MemoryManager &MemMgr, SymbolResolver &Resolver);
197 /// Add the referenced object file to the list of objects to be loaded and
199 std::unique_ptr<LoadedObjectInfo> loadObject(const object::ObjectFile &O);
201 /// Get the address of our local copy of the symbol. This may or may not
202 /// be the address used for relocation (clients can copy the data around
203 /// and resolve relocatons based on where they put it).
204 void *getSymbolLocalAddress(StringRef Name) const;
206 /// Get the target address and flags for the named symbol.
207 /// This address is the one used for relocation.
208 SymbolInfo getSymbol(StringRef Name) const;
210 /// Resolve the relocations for all symbols we currently know about.
211 void resolveRelocations();
213 /// Map a section to its target address space value.
214 /// Map the address of a JIT section as returned from the memory manager
215 /// to the address in the target process as the running code will see it.
216 /// This is the address which will be used for relocation resolution.
217 void mapSectionAddress(const void *LocalAddress, uint64_t TargetAddress);
219 /// Register any EH frame sections that have been loaded but not previously
220 /// registered with the memory manager. Note, RuntimeDyld is responsible
221 /// for identifying the EH frame and calling the memory manager with the
222 /// EH frame section data. However, the memory manager itself will handle
223 /// the actual target-specific EH frame registration.
224 void registerEHFrames();
226 void deregisterEHFrames();
229 StringRef getErrorString();
231 /// By default, only sections that are "required for execution" are passed to
232 /// the RTDyldMemoryManager, and other sections are discarded. Passing 'true'
233 /// to this method will cause RuntimeDyld to pass all sections to its
234 /// memory manager regardless of whether they are "required to execute" in the
235 /// usual sense. This is useful for inspecting metadata sections that may not
236 /// contain relocations, E.g. Debug info, stackmaps.
238 /// Must be called before the first object file is loaded.
239 void setProcessAllSections(bool ProcessAllSections) {
240 assert(!Dyld && "setProcessAllSections must be called before loadObject.");
241 this->ProcessAllSections = ProcessAllSections;
245 // RuntimeDyldImpl is the actual class. RuntimeDyld is just the public
247 std::unique_ptr<RuntimeDyldImpl> Dyld;
248 MemoryManager &MemMgr;
249 SymbolResolver &Resolver;
250 bool ProcessAllSections;
251 RuntimeDyldCheckerImpl *Checker;
254 } // end namespace llvm
256 #endif // LLVM_EXECUTIONENGINE_RUNTIMEDYLD_H