include/llvm/ExecutionEngine/Orc/ObjectLinkingLayer.h

   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 } // namespace jitlink
  39
  40 namespace object {
  41 class ObjectFile;
  42 } // namespace object
  43
  44 namespace orc {
  45
  46 class ObjectLinkingLayerJITLinkContext;
  47
  48 /// An ObjectLayer implementation built on JITLink.
  49 ///
  50 /// Clients can use this class to add relocatable object files to an
  51 /// ExecutionSession, and it typically serves as the base layer (underneath
  52 /// a compiling layer like IRCompileLayer) for the rest of the JIT.
  53 class ObjectLinkingLayer : public ObjectLayer {
  54   friend class ObjectLinkingLayerJITLinkContext;
  55
  56 public:
  57   /// Plugin instances can be added to the ObjectLinkingLayer to receive
  58   /// callbacks when code is loaded or emitted, and when JITLink is being
  59   /// configured.
  60   class Plugin {
  61   public:
  62     virtual ~Plugin();
  63     virtual void modifyPassConfig(MaterializationResponsibility &MR,
  64                                   const Triple &TT,
  65                                   jitlink::PassConfiguration &Config) {}
  66     virtual void notifyLoaded(MaterializationResponsibility &MR) {}
  67     virtual Error notifyEmitted(MaterializationResponsibility &MR) {
  68       return Error::success();
  69     }
  70     virtual Error notifyRemovingModule(VModuleKey K) {
  71       return Error::success();
  72     }
  73     virtual Error notifyRemovingAllModules() { return Error::success(); }
  74   };
  75
  76   using ReturnObjectBufferFunction =
  77       std::function<void(std::unique_ptr<MemoryBuffer>)>;
  78
  79   /// Construct an ObjectLinkingLayer with the given NotifyLoaded,
  80   /// and NotifyEmitted functors.
  81   ObjectLinkingLayer(ExecutionSession &ES,
  82                      jitlink::JITLinkMemoryManager &MemMgr);
  83
  84   /// Destruct an ObjectLinkingLayer.
  85   ~ObjectLinkingLayer();
  86
  87   /// Set an object buffer return function. By default object buffers are
  88   /// deleted once the JIT has linked them. If a return function is set then
  89   /// it will be called to transfer ownership of the buffer instead.
  90   void setReturnObjectBuffer(ReturnObjectBufferFunction ReturnObjectBuffer) {
  91     this->ReturnObjectBuffer = std::move(ReturnObjectBuffer);
  92   }
  93
  94   /// Add a pass-config modifier.
  95   ObjectLinkingLayer &addPlugin(std::unique_ptr<Plugin> P) {
  96     std::lock_guard<std::mutex> Lock(LayerMutex);
  97     Plugins.push_back(std::move(P));
  98     return *this;
  99   }
 100
 101   /// Emit the object.
 102   void emit(MaterializationResponsibility R,
 103             std::unique_ptr<MemoryBuffer> O) override;
 104
 105   /// Instructs this ObjectLinkingLayer instance to override the symbol flags
 106   /// found in the AtomGraph with the flags supplied by the
 107   /// MaterializationResponsibility instance. This is a workaround to support
 108   /// symbol visibility in COFF, which does not use the libObject's
 109   /// SF_Exported flag. Use only when generating / adding COFF object files.
 110   ///
 111   /// FIXME: We should be able to remove this if/when COFF properly tracks
 112   /// exported symbols.
 113   ObjectLinkingLayer &
 114   setOverrideObjectFlagsWithResponsibilityFlags(bool OverrideObjectFlags) {
 115     this->OverrideObjectFlags = OverrideObjectFlags;
 116     return *this;
 117   }
 118
 119   /// If set, this ObjectLinkingLayer instance will claim responsibility
 120   /// for any symbols provided by a given object file that were not already in
 121   /// the MaterializationResponsibility instance. Setting this flag allows
 122   /// higher-level program representations (e.g. LLVM IR) to be added based on
 123   /// only a subset of the symbols they provide, without having to write
 124   /// intervening layers to scan and add the additional symbols. This trades
 125   /// diagnostic quality for convenience however: If all symbols are enumerated
 126   /// up-front then clashes can be detected and reported early (and usually
 127   /// deterministically). If this option is set, clashes for the additional
 128   /// symbols may not be detected until late, and detection may depend on
 129   /// the flow of control through JIT'd code. Use with care.
 130   ObjectLinkingLayer &
 131   setAutoClaimResponsibilityForObjectSymbols(bool AutoClaimObjectSymbols) {
 132     this->AutoClaimObjectSymbols = AutoClaimObjectSymbols;
 133     return *this;
 134   }
 135
 136 private:
 137   using AllocPtr = std::unique_ptr<jitlink::JITLinkMemoryManager::Allocation>;
 138
 139   void modifyPassConfig(MaterializationResponsibility &MR, const Triple &TT,
 140                         jitlink::PassConfiguration &PassConfig);
 141   void notifyLoaded(MaterializationResponsibility &MR);
 142   Error notifyEmitted(MaterializationResponsibility &MR, AllocPtr Alloc);
 143
 144   Error removeModule(VModuleKey K);
 145   Error removeAllModules();
 146
 147   mutable std::mutex LayerMutex;
 148   jitlink::JITLinkMemoryManager &MemMgr;
 149   bool OverrideObjectFlags = false;
 150   bool AutoClaimObjectSymbols = false;
 151   ReturnObjectBufferFunction ReturnObjectBuffer;
 152   DenseMap<VModuleKey, AllocPtr> TrackedAllocs;
 153   std::vector<AllocPtr> UntrackedAllocs;
 154   std::vector<std::unique_ptr<Plugin>> Plugins;
 155 };
 156
 157 class EHFrameRegistrationPlugin : public ObjectLinkingLayer::Plugin {
 158 public:
 159   EHFrameRegistrationPlugin(jitlink::EHFrameRegistrar &Registrar);
 160   Error notifyEmitted(MaterializationResponsibility &MR) override;
 161   void modifyPassConfig(MaterializationResponsibility &MR, const Triple &TT,
 162                         jitlink::PassConfiguration &PassConfig) override;
 163   Error notifyRemovingModule(VModuleKey K) override;
 164   Error notifyRemovingAllModules() override;
 165
 166 private:
 167
 168   struct EHFrameRange {
 169     JITTargetAddress Addr = 0;
 170     size_t Size;
 171   };
 172
 173   jitlink::EHFrameRegistrar &Registrar;
 174   DenseMap<MaterializationResponsibility *, EHFrameRange> InProcessLinks;
 175   DenseMap<VModuleKey, EHFrameRange> TrackedEHFrameRanges;
 176   std::vector<EHFrameRange> UntrackedEHFrameRanges;
 177 };
 178
 179 } // end namespace orc
 180 } // end namespace llvm
 181
 182 #endif // LLVM_EXECUTIONENGINE_ORC_OBJECTLINKINGLAYER_H