1 //===-- ObjectLinkingLayer.h - JITLink-based jit linking layer --*- 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 // Contains the definition for an JITLink-based, in-process object linking 10 // layer. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #ifndef LLVM_EXECUTIONENGINE_ORC_OBJECTLINKINGLAYER_H 15 #define LLVM_EXECUTIONENGINE_ORC_OBJECTLINKINGLAYER_H 16 17 #include "llvm/ADT/STLExtras.h" 18 #include "llvm/ADT/StringMap.h" 19 #include "llvm/ADT/StringRef.h" 20 #include "llvm/ExecutionEngine/JITLink/JITLink.h" 21 #include "llvm/ExecutionEngine/JITSymbol.h" 22 #include "llvm/ExecutionEngine/Orc/Core.h" 23 #include "llvm/ExecutionEngine/Orc/Layer.h" 24 #include "llvm/Support/Error.h" 25 #include <algorithm> 26 #include <cassert> 27 #include <functional> 28 #include <list> 29 #include <memory> 30 #include <string> 31 #include <utility> 32 #include <vector> 33 34 namespace llvm { 35 36 namespace jitlink { 37 class EHFrameRegistrar; 38 class LinkGraph; 39 class Symbol; 40 } // namespace jitlink 41 42 namespace object { 43 class ObjectFile; 44 } // namespace object 45 46 namespace orc { 47 48 class ObjectLinkingLayerJITLinkContext; 49 50 /// An ObjectLayer implementation built on JITLink. 51 /// 52 /// Clients can use this class to add relocatable object files to an 53 /// ExecutionSession, and it typically serves as the base layer (underneath 54 /// a compiling layer like IRCompileLayer) for the rest of the JIT. 55 class ObjectLinkingLayer : public RTTIExtends<ObjectLinkingLayer, ObjectLayer>, 56 private ResourceManager { 57 friend class ObjectLinkingLayerJITLinkContext; 58 59 public: 60 static char ID; 61 62 /// Plugin instances can be added to the ObjectLinkingLayer to receive 63 /// callbacks when code is loaded or emitted, and when JITLink is being 64 /// configured. 65 class Plugin { 66 public: 67 using JITLinkSymbolVector = std::vector<const jitlink::Symbol *>; 68 using LocalDependenciesMap = DenseMap<SymbolStringPtr, JITLinkSymbolVector>; 69 70 virtual ~Plugin(); modifyPassConfig(MaterializationResponsibility & MR,jitlink::LinkGraph & G,jitlink::PassConfiguration & Config)71 virtual void modifyPassConfig(MaterializationResponsibility &MR, 72 jitlink::LinkGraph &G, 73 jitlink::PassConfiguration &Config) {} 74 75 // Deprecated. Don't use this in new code. There will be a proper mechanism 76 // for capturing object buffers. notifyMaterializing(MaterializationResponsibility & MR,jitlink::LinkGraph & G,jitlink::JITLinkContext & Ctx,MemoryBufferRef InputObject)77 virtual void notifyMaterializing(MaterializationResponsibility &MR, 78 jitlink::LinkGraph &G, 79 jitlink::JITLinkContext &Ctx, 80 MemoryBufferRef InputObject) {} 81 notifyLoaded(MaterializationResponsibility & MR)82 virtual void notifyLoaded(MaterializationResponsibility &MR) {} notifyEmitted(MaterializationResponsibility & MR)83 virtual Error notifyEmitted(MaterializationResponsibility &MR) { 84 return Error::success(); 85 } 86 virtual Error notifyFailed(MaterializationResponsibility &MR) = 0; 87 virtual Error notifyRemovingResources(ResourceKey K) = 0; 88 virtual void notifyTransferringResources(ResourceKey DstKey, 89 ResourceKey SrcKey) = 0; 90 91 /// Return any dependencies that synthetic symbols (e.g. init symbols) 92 /// have on locally scoped jitlink::Symbols. This is used by the 93 /// ObjectLinkingLayer to update the dependencies for the synthetic 94 /// symbols. 95 virtual LocalDependenciesMap getSyntheticSymbolLocalDependencies(MaterializationResponsibility & MR)96 getSyntheticSymbolLocalDependencies(MaterializationResponsibility &MR) { 97 return LocalDependenciesMap(); 98 } 99 }; 100 101 using ReturnObjectBufferFunction = 102 std::function<void(std::unique_ptr<MemoryBuffer>)>; 103 104 /// Construct an ObjectLinkingLayer. 105 ObjectLinkingLayer(ExecutionSession &ES, 106 jitlink::JITLinkMemoryManager &MemMgr); 107 108 /// Construct an ObjectLinkingLayer. Takes ownership of the given 109 /// JITLinkMemoryManager. This method is a temporary hack to simplify 110 /// co-existence with RTDyldObjectLinkingLayer (which also owns its 111 /// allocators). 112 ObjectLinkingLayer(ExecutionSession &ES, 113 std::unique_ptr<jitlink::JITLinkMemoryManager> MemMgr); 114 115 /// Destruct an ObjectLinkingLayer. 116 ~ObjectLinkingLayer(); 117 118 /// Set an object buffer return function. By default object buffers are 119 /// deleted once the JIT has linked them. If a return function is set then 120 /// it will be called to transfer ownership of the buffer instead. setReturnObjectBuffer(ReturnObjectBufferFunction ReturnObjectBuffer)121 void setReturnObjectBuffer(ReturnObjectBufferFunction ReturnObjectBuffer) { 122 this->ReturnObjectBuffer = std::move(ReturnObjectBuffer); 123 } 124 125 /// Add a pass-config modifier. addPlugin(std::unique_ptr<Plugin> P)126 ObjectLinkingLayer &addPlugin(std::unique_ptr<Plugin> P) { 127 std::lock_guard<std::mutex> Lock(LayerMutex); 128 Plugins.push_back(std::move(P)); 129 return *this; 130 } 131 132 /// Add a LinkGraph to the JITDylib targeted by the given tracker. 133 Error add(ResourceTrackerSP, std::unique_ptr<jitlink::LinkGraph> G); 134 135 /// Add a LinkGraph to the given JITDylib. add(JITDylib & JD,std::unique_ptr<jitlink::LinkGraph> G)136 Error add(JITDylib &JD, std::unique_ptr<jitlink::LinkGraph> G) { 137 return add(JD.getDefaultResourceTracker(), std::move(G)); 138 } 139 140 // Un-hide ObjectLayer add methods. 141 using ObjectLayer::add; 142 143 /// Emit an object file. 144 void emit(std::unique_ptr<MaterializationResponsibility> R, 145 std::unique_ptr<MemoryBuffer> O) override; 146 147 /// Emit a LinkGraph. 148 void emit(std::unique_ptr<MaterializationResponsibility> R, 149 std::unique_ptr<jitlink::LinkGraph> G); 150 151 /// Instructs this ObjectLinkingLayer instance to override the symbol flags 152 /// found in the AtomGraph with the flags supplied by the 153 /// MaterializationResponsibility instance. This is a workaround to support 154 /// symbol visibility in COFF, which does not use the libObject's 155 /// SF_Exported flag. Use only when generating / adding COFF object files. 156 /// 157 /// FIXME: We should be able to remove this if/when COFF properly tracks 158 /// exported symbols. 159 ObjectLinkingLayer & setOverrideObjectFlagsWithResponsibilityFlags(bool OverrideObjectFlags)160 setOverrideObjectFlagsWithResponsibilityFlags(bool OverrideObjectFlags) { 161 this->OverrideObjectFlags = OverrideObjectFlags; 162 return *this; 163 } 164 165 /// If set, this ObjectLinkingLayer instance will claim responsibility 166 /// for any symbols provided by a given object file that were not already in 167 /// the MaterializationResponsibility instance. Setting this flag allows 168 /// higher-level program representations (e.g. LLVM IR) to be added based on 169 /// only a subset of the symbols they provide, without having to write 170 /// intervening layers to scan and add the additional symbols. This trades 171 /// diagnostic quality for convenience however: If all symbols are enumerated 172 /// up-front then clashes can be detected and reported early (and usually 173 /// deterministically). If this option is set, clashes for the additional 174 /// symbols may not be detected until late, and detection may depend on 175 /// the flow of control through JIT'd code. Use with care. 176 ObjectLinkingLayer & setAutoClaimResponsibilityForObjectSymbols(bool AutoClaimObjectSymbols)177 setAutoClaimResponsibilityForObjectSymbols(bool AutoClaimObjectSymbols) { 178 this->AutoClaimObjectSymbols = AutoClaimObjectSymbols; 179 return *this; 180 } 181 182 private: 183 using AllocPtr = std::unique_ptr<jitlink::JITLinkMemoryManager::Allocation>; 184 185 void modifyPassConfig(MaterializationResponsibility &MR, 186 jitlink::LinkGraph &G, 187 jitlink::PassConfiguration &PassConfig); 188 void notifyLoaded(MaterializationResponsibility &MR); 189 Error notifyEmitted(MaterializationResponsibility &MR, AllocPtr Alloc); 190 191 Error handleRemoveResources(ResourceKey K) override; 192 void handleTransferResources(ResourceKey DstKey, ResourceKey SrcKey) override; 193 194 mutable std::mutex LayerMutex; 195 jitlink::JITLinkMemoryManager &MemMgr; 196 std::unique_ptr<jitlink::JITLinkMemoryManager> MemMgrOwnership; 197 bool OverrideObjectFlags = false; 198 bool AutoClaimObjectSymbols = false; 199 ReturnObjectBufferFunction ReturnObjectBuffer; 200 DenseMap<ResourceKey, std::vector<AllocPtr>> Allocs; 201 std::vector<std::unique_ptr<Plugin>> Plugins; 202 }; 203 204 class EHFrameRegistrationPlugin : public ObjectLinkingLayer::Plugin { 205 public: 206 EHFrameRegistrationPlugin( 207 ExecutionSession &ES, 208 std::unique_ptr<jitlink::EHFrameRegistrar> Registrar); 209 void modifyPassConfig(MaterializationResponsibility &MR, 210 jitlink::LinkGraph &G, 211 jitlink::PassConfiguration &PassConfig) override; 212 Error notifyEmitted(MaterializationResponsibility &MR) override; 213 Error notifyFailed(MaterializationResponsibility &MR) override; 214 Error notifyRemovingResources(ResourceKey K) override; 215 void notifyTransferringResources(ResourceKey DstKey, 216 ResourceKey SrcKey) override; 217 218 private: 219 220 struct EHFrameRange { 221 JITTargetAddress Addr = 0; 222 size_t Size; 223 }; 224 225 std::mutex EHFramePluginMutex; 226 ExecutionSession &ES; 227 std::unique_ptr<jitlink::EHFrameRegistrar> Registrar; 228 DenseMap<MaterializationResponsibility *, EHFrameRange> InProcessLinks; 229 DenseMap<ResourceKey, std::vector<EHFrameRange>> EHFrameRanges; 230 }; 231 232 } // end namespace orc 233 } // end namespace llvm 234 235 #endif // LLVM_EXECUTIONENGINE_ORC_OBJECTLINKINGLAYER_H 236