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

source code of llvm/include/llvm/ExecutionEngine/Orc/ObjectLinkingLayer.h