1 //===-- ELFNixPlatform.h -- Utilities for executing ELF in Orc --*- 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 // Linux/BSD support for executing JIT'd ELF in Orc. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #ifndef LLVM_EXECUTIONENGINE_ORC_ELFNIXPLATFORM_H 14 #define LLVM_EXECUTIONENGINE_ORC_ELFNIXPLATFORM_H 15 16 #include "llvm/ADT/StringRef.h" 17 #include "llvm/ExecutionEngine/Orc/Core.h" 18 #include "llvm/ExecutionEngine/Orc/ExecutorProcessControl.h" 19 #include "llvm/ExecutionEngine/Orc/ObjectLinkingLayer.h" 20 #include "llvm/ExecutionEngine/Orc/Shared/ExecutorAddress.h" 21 22 #include <future> 23 #include <thread> 24 #include <vector> 25 26 namespace llvm { 27 namespace orc { 28 29 struct ELFPerObjectSectionsToRegister { 30 ExecutorAddrRange EHFrameSection; 31 ExecutorAddrRange ThreadDataSection; 32 }; 33 34 struct ELFNixJITDylibInitializers { 35 using SectionList = std::vector<ExecutorAddrRange>; 36 37 ELFNixJITDylibInitializers(std::string Name, ExecutorAddr DSOHandleAddress) 38 : Name(std::move(Name)), DSOHandleAddress(std::move(DSOHandleAddress)) {} 39 40 std::string Name; 41 ExecutorAddr DSOHandleAddress; 42 43 StringMap<SectionList> InitSections; 44 }; 45 46 class ELFNixJITDylibDeinitializers {}; 47 48 using ELFNixJITDylibInitializerSequence = 49 std::vector<ELFNixJITDylibInitializers>; 50 51 using ELFNixJITDylibDeinitializerSequence = 52 std::vector<ELFNixJITDylibDeinitializers>; 53 54 /// Mediates between ELFNix initialization and ExecutionSession state. 55 class ELFNixPlatform : public Platform { 56 public: 57 /// Try to create a ELFNixPlatform instance, adding the ORC runtime to the 58 /// given JITDylib. 59 /// 60 /// The ORC runtime requires access to a number of symbols in 61 /// libc++. It is up to the caller to ensure that the requried 62 /// symbols can be referenced by code added to PlatformJD. The 63 /// standard way to achieve this is to first attach dynamic library 64 /// search generators for either the given process, or for the 65 /// specific required libraries, to PlatformJD, then to create the 66 /// platform instance: 67 /// 68 /// \code{.cpp} 69 /// auto &PlatformJD = ES.createBareJITDylib("stdlib"); 70 /// PlatformJD.addGenerator( 71 /// ExitOnErr(EPCDynamicLibrarySearchGenerator 72 /// ::GetForTargetProcess(EPC))); 73 /// ES.setPlatform( 74 /// ExitOnErr(ELFNixPlatform::Create(ES, ObjLayer, EPC, PlatformJD, 75 /// "/path/to/orc/runtime"))); 76 /// \endcode 77 /// 78 /// Alternatively, these symbols could be added to another JITDylib that 79 /// PlatformJD links against. 80 /// 81 /// Clients are also responsible for ensuring that any JIT'd code that 82 /// depends on runtime functions (including any code using TLV or static 83 /// destructors) can reference the runtime symbols. This is usually achieved 84 /// by linking any JITDylibs containing regular code against 85 /// PlatformJD. 86 /// 87 /// By default, ELFNixPlatform will add the set of aliases returned by the 88 /// standardPlatformAliases function. This includes both required aliases 89 /// (e.g. __cxa_atexit -> __orc_rt_elf_cxa_atexit for static destructor 90 /// support), and optional aliases that provide JIT versions of common 91 /// functions (e.g. dlopen -> __orc_rt_elf_jit_dlopen). Clients can 92 /// override these defaults by passing a non-None value for the 93 /// RuntimeAliases function, in which case the client is responsible for 94 /// setting up all aliases (including the required ones). 95 static Expected<std::unique_ptr<ELFNixPlatform>> 96 Create(ExecutionSession &ES, ObjectLinkingLayer &ObjLinkingLayer, 97 JITDylib &PlatformJD, const char *OrcRuntimePath, 98 std::optional<SymbolAliasMap> RuntimeAliases = std::nullopt); 99 100 ExecutionSession &getExecutionSession() const { return ES; } 101 ObjectLinkingLayer &getObjectLinkingLayer() const { return ObjLinkingLayer; } 102 103 Error setupJITDylib(JITDylib &JD) override; 104 Error teardownJITDylib(JITDylib &JD) override; 105 Error notifyAdding(ResourceTracker &RT, 106 const MaterializationUnit &MU) override; 107 Error notifyRemoving(ResourceTracker &RT) override; 108 109 /// Returns an AliasMap containing the default aliases for the ELFNixPlatform. 110 /// This can be modified by clients when constructing the platform to add 111 /// or remove aliases. 112 static Expected<SymbolAliasMap> standardPlatformAliases(ExecutionSession &ES, 113 JITDylib &PlatformJD); 114 115 /// Returns the array of required CXX aliases. 116 static ArrayRef<std::pair<const char *, const char *>> requiredCXXAliases(); 117 118 /// Returns the array of standard runtime utility aliases for ELF. 119 static ArrayRef<std::pair<const char *, const char *>> 120 standardRuntimeUtilityAliases(); 121 122 /// Returns true if the given section name is an initializer section. 123 static bool isInitializerSection(StringRef SecName); 124 125 private: 126 // The ELFNixPlatformPlugin scans/modifies LinkGraphs to support ELF 127 // platform features including initializers, exceptions, TLV, and language 128 // runtime registration. 129 class ELFNixPlatformPlugin : public ObjectLinkingLayer::Plugin { 130 public: 131 ELFNixPlatformPlugin(ELFNixPlatform &MP) : MP(MP) {} 132 133 void modifyPassConfig(MaterializationResponsibility &MR, 134 jitlink::LinkGraph &G, 135 jitlink::PassConfiguration &Config) override; 136 137 SyntheticSymbolDependenciesMap 138 getSyntheticSymbolDependencies(MaterializationResponsibility &MR) override; 139 140 // FIXME: We should be tentatively tracking scraped sections and discarding 141 // if the MR fails. 142 Error notifyFailed(MaterializationResponsibility &MR) override { 143 return Error::success(); 144 } 145 146 Error notifyRemovingResources(JITDylib &JD, ResourceKey K) override { 147 return Error::success(); 148 } 149 150 void notifyTransferringResources(JITDylib &JD, ResourceKey DstKey, 151 ResourceKey SrcKey) override {} 152 153 private: 154 using InitSymbolDepMap = 155 DenseMap<MaterializationResponsibility *, JITLinkSymbolSet>; 156 157 void addInitializerSupportPasses(MaterializationResponsibility &MR, 158 jitlink::PassConfiguration &Config); 159 160 void addDSOHandleSupportPasses(MaterializationResponsibility &MR, 161 jitlink::PassConfiguration &Config); 162 163 void addEHAndTLVSupportPasses(MaterializationResponsibility &MR, 164 jitlink::PassConfiguration &Config); 165 166 Error preserveInitSections(jitlink::LinkGraph &G, 167 MaterializationResponsibility &MR); 168 169 Error registerInitSections(jitlink::LinkGraph &G, JITDylib &JD); 170 171 Error fixTLVSectionsAndEdges(jitlink::LinkGraph &G, JITDylib &JD); 172 173 std::mutex PluginMutex; 174 ELFNixPlatform &MP; 175 InitSymbolDepMap InitSymbolDeps; 176 }; 177 178 using SendInitializerSequenceFn = 179 unique_function<void(Expected<ELFNixJITDylibInitializerSequence>)>; 180 181 using SendDeinitializerSequenceFn = 182 unique_function<void(Expected<ELFNixJITDylibDeinitializerSequence>)>; 183 184 using SendSymbolAddressFn = unique_function<void(Expected<ExecutorAddr>)>; 185 186 static bool supportedTarget(const Triple &TT); 187 188 ELFNixPlatform(ExecutionSession &ES, ObjectLinkingLayer &ObjLinkingLayer, 189 JITDylib &PlatformJD, 190 std::unique_ptr<DefinitionGenerator> OrcRuntimeGenerator, 191 Error &Err); 192 193 // Associate ELFNixPlatform JIT-side runtime support functions with handlers. 194 Error associateRuntimeSupportFunctions(JITDylib &PlatformJD); 195 196 void getInitializersBuildSequencePhase(SendInitializerSequenceFn SendResult, 197 JITDylib &JD, 198 std::vector<JITDylibSP> DFSLinkOrder); 199 200 void getInitializersLookupPhase(SendInitializerSequenceFn SendResult, 201 JITDylib &JD); 202 203 void rt_getInitializers(SendInitializerSequenceFn SendResult, 204 StringRef JDName); 205 206 void rt_getDeinitializers(SendDeinitializerSequenceFn SendResult, 207 ExecutorAddr Handle); 208 209 void rt_lookupSymbol(SendSymbolAddressFn SendResult, ExecutorAddr Handle, 210 StringRef SymbolName); 211 212 // Records the addresses of runtime symbols used by the platform. 213 Error bootstrapELFNixRuntime(JITDylib &PlatformJD); 214 215 Error registerInitInfo(JITDylib &JD, 216 ArrayRef<jitlink::Section *> InitSections); 217 218 Error registerPerObjectSections(const ELFPerObjectSectionsToRegister &POSR); 219 220 Expected<uint64_t> createPThreadKey(); 221 222 ExecutionSession &ES; 223 ObjectLinkingLayer &ObjLinkingLayer; 224 225 SymbolStringPtr DSOHandleSymbol; 226 std::atomic<bool> RuntimeBootstrapped{false}; 227 228 ExecutorAddr orc_rt_elfnix_platform_bootstrap; 229 ExecutorAddr orc_rt_elfnix_platform_shutdown; 230 ExecutorAddr orc_rt_elfnix_register_object_sections; 231 ExecutorAddr orc_rt_elfnix_create_pthread_key; 232 233 DenseMap<JITDylib *, SymbolLookupSet> RegisteredInitSymbols; 234 235 // InitSeqs gets its own mutex to avoid locking the whole session when 236 // aggregating data from the jitlink. 237 std::mutex PlatformMutex; 238 DenseMap<JITDylib *, ELFNixJITDylibInitializers> InitSeqs; 239 std::vector<ELFPerObjectSectionsToRegister> BootstrapPOSRs; 240 241 DenseMap<ExecutorAddr, JITDylib *> HandleAddrToJITDylib; 242 DenseMap<JITDylib *, uint64_t> JITDylibToPThreadKey; 243 }; 244 245 namespace shared { 246 247 using SPSELFPerObjectSectionsToRegister = 248 SPSTuple<SPSExecutorAddrRange, SPSExecutorAddrRange>; 249 250 template <> 251 class SPSSerializationTraits<SPSELFPerObjectSectionsToRegister, 252 ELFPerObjectSectionsToRegister> { 253 254 public: 255 static size_t size(const ELFPerObjectSectionsToRegister &MOPOSR) { 256 return SPSELFPerObjectSectionsToRegister::AsArgList::size( 257 MOPOSR.EHFrameSection, MOPOSR.ThreadDataSection); 258 } 259 260 static bool serialize(SPSOutputBuffer &OB, 261 const ELFPerObjectSectionsToRegister &MOPOSR) { 262 return SPSELFPerObjectSectionsToRegister::AsArgList::serialize( 263 OB, MOPOSR.EHFrameSection, MOPOSR.ThreadDataSection); 264 } 265 266 static bool deserialize(SPSInputBuffer &IB, 267 ELFPerObjectSectionsToRegister &MOPOSR) { 268 return SPSELFPerObjectSectionsToRegister::AsArgList::deserialize( 269 IB, MOPOSR.EHFrameSection, MOPOSR.ThreadDataSection); 270 } 271 }; 272 273 using SPSNamedExecutorAddrRangeSequenceMap = 274 SPSSequence<SPSTuple<SPSString, SPSExecutorAddrRangeSequence>>; 275 276 using SPSELFNixJITDylibInitializers = 277 SPSTuple<SPSString, SPSExecutorAddr, SPSNamedExecutorAddrRangeSequenceMap>; 278 279 using SPSELFNixJITDylibInitializerSequence = 280 SPSSequence<SPSELFNixJITDylibInitializers>; 281 282 /// Serialization traits for ELFNixJITDylibInitializers. 283 template <> 284 class SPSSerializationTraits<SPSELFNixJITDylibInitializers, 285 ELFNixJITDylibInitializers> { 286 public: 287 static size_t size(const ELFNixJITDylibInitializers &MOJDIs) { 288 return SPSELFNixJITDylibInitializers::AsArgList::size( 289 MOJDIs.Name, MOJDIs.DSOHandleAddress, MOJDIs.InitSections); 290 } 291 292 static bool serialize(SPSOutputBuffer &OB, 293 const ELFNixJITDylibInitializers &MOJDIs) { 294 return SPSELFNixJITDylibInitializers::AsArgList::serialize( 295 OB, MOJDIs.Name, MOJDIs.DSOHandleAddress, MOJDIs.InitSections); 296 } 297 298 static bool deserialize(SPSInputBuffer &IB, 299 ELFNixJITDylibInitializers &MOJDIs) { 300 return SPSELFNixJITDylibInitializers::AsArgList::deserialize( 301 IB, MOJDIs.Name, MOJDIs.DSOHandleAddress, MOJDIs.InitSections); 302 } 303 }; 304 305 using SPSELFJITDylibDeinitializers = SPSEmpty; 306 307 using SPSELFJITDylibDeinitializerSequence = 308 SPSSequence<SPSELFJITDylibDeinitializers>; 309 310 template <> 311 class SPSSerializationTraits<SPSELFJITDylibDeinitializers, 312 ELFNixJITDylibDeinitializers> { 313 public: 314 static size_t size(const ELFNixJITDylibDeinitializers &MOJDDs) { return 0; } 315 316 static bool serialize(SPSOutputBuffer &OB, 317 const ELFNixJITDylibDeinitializers &MOJDDs) { 318 return true; 319 } 320 321 static bool deserialize(SPSInputBuffer &IB, 322 ELFNixJITDylibDeinitializers &MOJDDs) { 323 MOJDDs = ELFNixJITDylibDeinitializers(); 324 return true; 325 } 326 }; 327 328 } // end namespace shared 329 } // end namespace orc 330 } // end namespace llvm 331 332 #endif // LLVM_EXECUTIONENGINE_ORC_ELFNIXPLATFORM_H 333