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/Support/Memory.h"
21 #include "llvm/DebugInfo/DIContext.h"
28 template <typename T> class OwningBinary;
31 class RuntimeDyldImpl;
32 class RuntimeDyldCheckerImpl;
35 friend class RuntimeDyldCheckerImpl;
37 RuntimeDyld(const RuntimeDyld &) = delete;
38 void operator=(const RuntimeDyld &) = delete;
41 // Change the address associated with a section when resolving relocations.
42 // Any relocations already associated with the symbol will be re-resolved.
43 void reassignSectionAddress(unsigned SectionID, uint64_t Addr);
46 /// \brief Information about a named symbol.
47 class SymbolInfo : public JITSymbolBase {
49 SymbolInfo(std::nullptr_t) : JITSymbolBase(JITSymbolFlags::None), Address(0) {}
50 SymbolInfo(uint64_t Address, JITSymbolFlags Flags)
51 : JITSymbolBase(Flags), Address(Address) {}
52 explicit operator bool() const { return Address != 0; }
53 uint64_t getAddress() const { return Address; }
58 /// \brief Information about the loaded object.
59 class LoadedObjectInfo : public llvm::LoadedObjectInfo {
60 friend class RuntimeDyldImpl;
62 LoadedObjectInfo(RuntimeDyldImpl &RTDyld, unsigned BeginIdx,
64 : RTDyld(RTDyld), BeginIdx(BeginIdx), EndIdx(EndIdx) { }
66 virtual object::OwningBinary<object::ObjectFile>
67 getObjectForDebug(const object::ObjectFile &Obj) const = 0;
69 uint64_t getSectionLoadAddress(StringRef Name) const;
72 virtual void anchor();
74 RuntimeDyldImpl &RTDyld;
75 unsigned BeginIdx, EndIdx;
78 template <typename Derived> struct LoadedObjectInfoHelper : LoadedObjectInfo {
79 LoadedObjectInfoHelper(RuntimeDyldImpl &RTDyld, unsigned BeginIdx,
81 : LoadedObjectInfo(RTDyld, BeginIdx, EndIdx) {}
82 std::unique_ptr<llvm::LoadedObjectInfo> clone() const override {
83 return llvm::make_unique<Derived>(static_cast<const Derived &>(*this));
87 /// \brief Memory Management.
90 virtual ~MemoryManager() {}
92 /// Allocate a memory block of (at least) the given size suitable for
93 /// executable code. The SectionID is a unique identifier assigned by the
94 /// RuntimeDyld instance, and optionally recorded by the memory manager to
95 /// access a loaded section.
96 virtual uint8_t *allocateCodeSection(uintptr_t Size, unsigned Alignment,
98 StringRef SectionName) = 0;
100 /// Allocate a memory block of (at least) the given size suitable for data.
101 /// The SectionID is a unique identifier assigned by the JIT engine, and
102 /// optionally recorded by the memory manager to access a loaded section.
103 virtual uint8_t *allocateDataSection(uintptr_t Size, unsigned Alignment,
105 StringRef SectionName,
106 bool IsReadOnly) = 0;
108 /// Inform the memory manager about the total amount of memory required to
109 /// allocate all sections to be loaded:
110 /// \p CodeSize - the total size of all code sections
111 /// \p DataSizeRO - the total size of all read-only data sections
112 /// \p DataSizeRW - the total size of all read-write data sections
114 /// Note that by default the callback is disabled. To enable it
115 /// redefine the method needsToReserveAllocationSpace to return true.
116 virtual void reserveAllocationSpace(uintptr_t CodeSize,
117 uintptr_t DataSizeRO,
118 uintptr_t DataSizeRW) {}
120 /// Override to return true to enable the reserveAllocationSpace callback.
121 virtual bool needsToReserveAllocationSpace() { return false; }
123 /// Register the EH frames with the runtime so that c++ exceptions work.
125 /// \p Addr parameter provides the local address of the EH frame section
126 /// data, while \p LoadAddr provides the address of the data in the target
127 /// address space. If the section has not been remapped (which will usually
128 /// be the case for local execution) these two values will be the same.
129 virtual void registerEHFrames(uint8_t *Addr, uint64_t LoadAddr,
131 virtual void deregisterEHFrames(uint8_t *addr, uint64_t LoadAddr,
134 /// This method is called when object loading is complete and section page
135 /// permissions can be applied. It is up to the memory manager implementation
136 /// to decide whether or not to act on this method. The memory manager will
137 /// typically allocate all sections as read-write and then apply specific
138 /// permissions when this method is called. Code sections cannot be executed
139 /// until this function has been called. In addition, any cache coherency
140 /// operations needed to reliably use the memory are also performed.
142 /// Returns true if an error occurred, false otherwise.
143 virtual bool finalizeMemory(std::string *ErrMsg = nullptr) = 0;
146 virtual void anchor();
149 /// \brief Symbol resolution.
150 class SymbolResolver {
152 virtual ~SymbolResolver() {}
154 /// This method returns the address of the specified function or variable.
155 /// It is used to resolve symbols during module linking.
157 /// If the returned symbol's address is equal to ~0ULL then RuntimeDyld will
158 /// skip all relocations for that symbol, and the client will be responsible
159 /// for handling them manually.
160 virtual SymbolInfo findSymbol(const std::string &Name) = 0;
162 /// This method returns the address of the specified symbol if it exists
163 /// within the logical dynamic library represented by this
164 /// RTDyldMemoryManager. Unlike getSymbolAddress, queries through this
165 /// interface should return addresses for hidden symbols.
167 /// This is of particular importance for the Orc JIT APIs, which support lazy
168 /// compilation by breaking up modules: Each of those broken out modules
169 /// must be able to resolve hidden symbols provided by the others. Clients
170 /// writing memory managers for MCJIT can usually ignore this method.
172 /// This method will be queried by RuntimeDyld when checking for previous
173 /// definitions of common symbols. It will *not* be queried by default when
174 /// resolving external symbols (this minimises the link-time overhead for
175 /// MCJIT clients who don't care about Orc features). If you are writing a
176 /// RTDyldMemoryManager for Orc and want "external" symbol resolution to
177 /// search the logical dylib, you should override your getSymbolAddress
178 /// method call this method directly.
179 virtual SymbolInfo findSymbolInLogicalDylib(const std::string &Name) = 0;
181 virtual void anchor();
184 /// \brief Construct a RuntimeDyld instance.
185 RuntimeDyld(MemoryManager &MemMgr, SymbolResolver &Resolver);
188 /// Add the referenced object file to the list of objects to be loaded and
190 std::unique_ptr<LoadedObjectInfo> loadObject(const object::ObjectFile &O);
192 /// Get the address of our local copy of the symbol. This may or may not
193 /// be the address used for relocation (clients can copy the data around
194 /// and resolve relocatons based on where they put it).
195 void *getSymbolLocalAddress(StringRef Name) const;
197 /// Get the target address and flags for the named symbol.
198 /// This address is the one used for relocation.
199 SymbolInfo getSymbol(StringRef Name) const;
201 /// Resolve the relocations for all symbols we currently know about.
202 void resolveRelocations();
204 /// Map a section to its target address space value.
205 /// Map the address of a JIT section as returned from the memory manager
206 /// to the address in the target process as the running code will see it.
207 /// This is the address which will be used for relocation resolution.
208 void mapSectionAddress(const void *LocalAddress, uint64_t TargetAddress);
210 /// Register any EH frame sections that have been loaded but not previously
211 /// registered with the memory manager. Note, RuntimeDyld is responsible
212 /// for identifying the EH frame and calling the memory manager with the
213 /// EH frame section data. However, the memory manager itself will handle
214 /// the actual target-specific EH frame registration.
215 void registerEHFrames();
217 void deregisterEHFrames();
220 StringRef getErrorString();
222 /// By default, only sections that are "required for execution" are passed to
223 /// the RTDyldMemoryManager, and other sections are discarded. Passing 'true'
224 /// to this method will cause RuntimeDyld to pass all sections to its
225 /// memory manager regardless of whether they are "required to execute" in the
226 /// usual sense. This is useful for inspecting metadata sections that may not
227 /// contain relocations, E.g. Debug info, stackmaps.
229 /// Must be called before the first object file is loaded.
230 void setProcessAllSections(bool ProcessAllSections) {
231 assert(!Dyld && "setProcessAllSections must be called before loadObject.");
232 this->ProcessAllSections = ProcessAllSections;
236 // RuntimeDyldImpl is the actual class. RuntimeDyld is just the public
238 std::unique_ptr<RuntimeDyldImpl> Dyld;
239 MemoryManager &MemMgr;
240 SymbolResolver &Resolver;
241 bool ProcessAllSections;
242 RuntimeDyldCheckerImpl *Checker;
245 } // end namespace llvm