Line data Source code
1 : //===- RuntimeDyld.h - Run-time dynamic linker for MC-JIT -------*- 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 : // Interface for the runtime dynamic linker facilities of the MC-JIT.
11 : //
12 : //===----------------------------------------------------------------------===//
13 :
14 : #ifndef LLVM_EXECUTIONENGINE_RUNTIMEDYLD_H
15 : #define LLVM_EXECUTIONENGINE_RUNTIMEDYLD_H
16 :
17 : #include "llvm/ADT/STLExtras.h"
18 : #include "llvm/ADT/StringRef.h"
19 : #include "llvm/DebugInfo/DIContext.h"
20 : #include "llvm/ExecutionEngine/JITSymbol.h"
21 : #include "llvm/Object/ObjectFile.h"
22 : #include "llvm/Support/Error.h"
23 : #include <algorithm>
24 : #include <cassert>
25 : #include <cstddef>
26 : #include <cstdint>
27 : #include <map>
28 : #include <memory>
29 : #include <string>
30 : #include <system_error>
31 :
32 : namespace llvm {
33 :
34 : namespace object {
35 :
36 : template <typename T> class OwningBinary;
37 :
38 : } // end namespace object
39 :
40 : /// Base class for errors originating in RuntimeDyld, e.g. missing relocation
41 : /// support.
42 : class RuntimeDyldError : public ErrorInfo<RuntimeDyldError> {
43 : public:
44 : static char ID;
45 :
46 0 : RuntimeDyldError(std::string ErrMsg) : ErrMsg(std::move(ErrMsg)) {}
47 :
48 : void log(raw_ostream &OS) const override;
49 : const std::string &getErrorMessage() const { return ErrMsg; }
50 : std::error_code convertToErrorCode() const override;
51 :
52 : private:
53 : std::string ErrMsg;
54 : };
55 :
56 : class RuntimeDyldCheckerImpl;
57 : class RuntimeDyldImpl;
58 :
59 : class RuntimeDyld {
60 : friend class RuntimeDyldCheckerImpl;
61 :
62 : protected:
63 : // Change the address associated with a section when resolving relocations.
64 : // Any relocations already associated with the symbol will be re-resolved.
65 : void reassignSectionAddress(unsigned SectionID, uint64_t Addr);
66 :
67 : public:
68 : /// Information about the loaded object.
69 0 : class LoadedObjectInfo : public llvm::LoadedObjectInfo {
70 : friend class RuntimeDyldImpl;
71 :
72 : public:
73 : using ObjSectionToIDMap = std::map<object::SectionRef, unsigned>;
74 :
75 : LoadedObjectInfo(RuntimeDyldImpl &RTDyld, ObjSectionToIDMap ObjSecToIDMap)
76 350 : : RTDyld(RTDyld), ObjSecToIDMap(std::move(ObjSecToIDMap)) {}
77 :
78 : virtual object::OwningBinary<object::ObjectFile>
79 : getObjectForDebug(const object::ObjectFile &Obj) const = 0;
80 :
81 : uint64_t
82 : getSectionLoadAddress(const object::SectionRef &Sec) const override;
83 :
84 : protected:
85 : virtual void anchor();
86 :
87 : RuntimeDyldImpl &RTDyld;
88 : ObjSectionToIDMap ObjSecToIDMap;
89 : };
90 :
91 : /// Memory Management.
92 : class MemoryManager {
93 : friend class RuntimeDyld;
94 :
95 : public:
96 402 : MemoryManager() = default;
97 0 : virtual ~MemoryManager() = default;
98 :
99 : /// Allocate a memory block of (at least) the given size suitable for
100 : /// executable code. The SectionID is a unique identifier assigned by the
101 : /// RuntimeDyld instance, and optionally recorded by the memory manager to
102 : /// access a loaded section.
103 : virtual uint8_t *allocateCodeSection(uintptr_t Size, unsigned Alignment,
104 : unsigned SectionID,
105 : StringRef SectionName) = 0;
106 :
107 : /// Allocate a memory block of (at least) the given size suitable for data.
108 : /// The SectionID is a unique identifier assigned by the JIT engine, and
109 : /// optionally recorded by the memory manager to access a loaded section.
110 : virtual uint8_t *allocateDataSection(uintptr_t Size, unsigned Alignment,
111 : unsigned SectionID,
112 : StringRef SectionName,
113 : bool IsReadOnly) = 0;
114 :
115 : /// Inform the memory manager about the total amount of memory required to
116 : /// allocate all sections to be loaded:
117 : /// \p CodeSize - the total size of all code sections
118 : /// \p DataSizeRO - the total size of all read-only data sections
119 : /// \p DataSizeRW - the total size of all read-write data sections
120 : ///
121 : /// Note that by default the callback is disabled. To enable it
122 : /// redefine the method needsToReserveAllocationSpace to return true.
123 0 : virtual void reserveAllocationSpace(uintptr_t CodeSize, uint32_t CodeAlign,
124 : uintptr_t RODataSize,
125 : uint32_t RODataAlign,
126 : uintptr_t RWDataSize,
127 0 : uint32_t RWDataAlign) {}
128 :
129 : /// Override to return true to enable the reserveAllocationSpace callback.
130 316 : virtual bool needsToReserveAllocationSpace() { return false; }
131 :
132 : /// Register the EH frames with the runtime so that c++ exceptions work.
133 : ///
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,
139 : size_t Size) = 0;
140 : virtual void deregisterEHFrames() = 0;
141 :
142 : /// This method is called when object loading is complete and section page
143 : /// permissions can be applied. It is up to the memory manager implementation
144 : /// to decide whether or not to act on this method. The memory manager will
145 : /// typically allocate all sections as read-write and then apply specific
146 : /// permissions when this method is called. Code sections cannot be executed
147 : /// until this function has been called. In addition, any cache coherency
148 : /// operations needed to reliably use the memory are also performed.
149 : ///
150 : /// Returns true if an error occurred, false otherwise.
151 : virtual bool finalizeMemory(std::string *ErrMsg = nullptr) = 0;
152 :
153 : /// This method is called after an object has been loaded into memory but
154 : /// before relocations are applied to the loaded sections.
155 : ///
156 : /// Memory managers which are preparing code for execution in an external
157 : /// address space can use this call to remap the section addresses for the
158 : /// newly loaded object.
159 : ///
160 : /// For clients that do not need access to an ExecutionEngine instance this
161 : /// method should be preferred to its cousin
162 : /// MCJITMemoryManager::notifyObjectLoaded as this method is compatible with
163 : /// ORC JIT stacks.
164 320 : virtual void notifyObjectLoaded(RuntimeDyld &RTDyld,
165 320 : const object::ObjectFile &Obj) {}
166 :
167 : private:
168 : virtual void anchor();
169 :
170 : bool FinalizationLocked = false;
171 : };
172 :
173 : /// Construct a RuntimeDyld instance.
174 : RuntimeDyld(MemoryManager &MemMgr, JITSymbolResolver &Resolver);
175 : RuntimeDyld(const RuntimeDyld &) = delete;
176 : RuntimeDyld &operator=(const RuntimeDyld &) = delete;
177 : ~RuntimeDyld();
178 :
179 : /// Add the referenced object file to the list of objects to be loaded and
180 : /// relocated.
181 : std::unique_ptr<LoadedObjectInfo> loadObject(const object::ObjectFile &O);
182 :
183 : /// Get the address of our local copy of the symbol. This may or may not
184 : /// be the address used for relocation (clients can copy the data around
185 : /// and resolve relocatons based on where they put it).
186 : void *getSymbolLocalAddress(StringRef Name) const;
187 :
188 : /// Get the target address and flags for the named symbol.
189 : /// This address is the one used for relocation.
190 : JITEvaluatedSymbol getSymbol(StringRef Name) const;
191 :
192 : /// Returns a copy of the symbol table. This can be used by on-finalized
193 : /// callbacks to extract the symbol table before throwing away the
194 : /// RuntimeDyld instance. Because the map keys (StringRefs) are backed by
195 : /// strings inside the RuntimeDyld instance, the map should be processed
196 : /// before the RuntimeDyld instance is discarded.
197 : std::map<StringRef, JITEvaluatedSymbol> getSymbolTable() const;
198 :
199 : /// Resolve the relocations for all symbols we currently know about.
200 : void resolveRelocations();
201 :
202 : /// Map a section to its target address space value.
203 : /// Map the address of a JIT section as returned from the memory manager
204 : /// to the address in the target process as the running code will see it.
205 : /// This is the address which will be used for relocation resolution.
206 : void mapSectionAddress(const void *LocalAddress, uint64_t TargetAddress);
207 :
208 : /// Register any EH frame sections that have been loaded but not previously
209 : /// registered with the memory manager. Note, RuntimeDyld is responsible
210 : /// for identifying the EH frame and calling the memory manager with the
211 : /// EH frame section data. However, the memory manager itself will handle
212 : /// the actual target-specific EH frame registration.
213 : void registerEHFrames();
214 :
215 : void deregisterEHFrames();
216 :
217 : bool hasError();
218 : StringRef getErrorString();
219 :
220 : /// By default, only sections that are "required for execution" are passed to
221 : /// the RTDyldMemoryManager, and other sections are discarded. Passing 'true'
222 : /// to this method will cause RuntimeDyld to pass all sections to its
223 : /// memory manager regardless of whether they are "required to execute" in the
224 : /// usual sense. This is useful for inspecting metadata sections that may not
225 : /// contain relocations, E.g. Debug info, stackmaps.
226 : ///
227 : /// Must be called before the first object file is loaded.
228 : void setProcessAllSections(bool ProcessAllSections) {
229 : assert(!Dyld && "setProcessAllSections must be called before loadObject.");
230 175 : this->ProcessAllSections = ProcessAllSections;
231 : }
232 :
233 : /// Perform all actions needed to make the code owned by this RuntimeDyld
234 : /// instance executable:
235 : ///
236 : /// 1) Apply relocations.
237 : /// 2) Register EH frames.
238 : /// 3) Update memory permissions*.
239 : ///
240 : /// * Finalization is potentially recursive**, and the 3rd step will only be
241 : /// applied by the outermost call to finalize. This allows different
242 : /// RuntimeDyld instances to share a memory manager without the innermost
243 : /// finalization locking the memory and causing relocation fixup errors in
244 : /// outer instances.
245 : ///
246 : /// ** Recursive finalization occurs when one RuntimeDyld instances needs the
247 : /// address of a symbol owned by some other instance in order to apply
248 : /// relocations.
249 : ///
250 : void finalizeWithMemoryManagerLocking();
251 :
252 : private:
253 : friend void
254 : jitLinkForORC(object::ObjectFile &Obj,
255 : std::unique_ptr<MemoryBuffer> UnderlyingBuffer,
256 : RuntimeDyld::MemoryManager &MemMgr, JITSymbolResolver &Resolver,
257 : bool ProcessAllSections,
258 : std::function<Error(std::unique_ptr<LoadedObjectInfo>,
259 : std::map<StringRef, JITEvaluatedSymbol>)>
260 : OnLoaded,
261 : std::function<void(Error)> OnEmitted);
262 :
263 : // RuntimeDyldImpl is the actual class. RuntimeDyld is just the public
264 : // interface.
265 : std::unique_ptr<RuntimeDyldImpl> Dyld;
266 : MemoryManager &MemMgr;
267 : JITSymbolResolver &Resolver;
268 : bool ProcessAllSections;
269 : RuntimeDyldCheckerImpl *Checker;
270 : };
271 :
272 : // Asynchronous JIT link for ORC.
273 : //
274 : // Warning: This API is experimental and probably should not be used by anyone
275 : // but ORC's RTDyldObjectLinkingLayer2. Internally it constructs a RuntimeDyld
276 : // instance and uses continuation passing to perform the fix-up and finalize
277 : // steps asynchronously.
278 : void jitLinkForORC(object::ObjectFile &Obj,
279 : std::unique_ptr<MemoryBuffer> UnderlyingBuffer,
280 : RuntimeDyld::MemoryManager &MemMgr,
281 : JITSymbolResolver &Resolver, bool ProcessAllSections,
282 : std::function<Error(std::unique_ptr<LoadedObjectInfo>,
283 : std::map<StringRef, JITEvaluatedSymbol>)>
284 : OnLoaded,
285 : std::function<void(Error)> OnEmitted);
286 :
287 : } // end namespace llvm
288 :
289 : #endif // LLVM_EXECUTIONENGINE_RUNTIMEDYLD_H
|
