include/llvm/ExecutionEngine/Orc/OrcRemoteTargetClient.h

   1 //===---- OrcRemoteTargetClient.h - Orc Remote-target Client ----*- 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 // This file defines the OrcRemoteTargetClient class and helpers. This class
  11 // can be used to communicate over an RPCChannel with an OrcRemoteTargetServer
  12 // instance to support remote-JITing.
  13 //
  14 //===----------------------------------------------------------------------===//
  15
  16 #ifndef LLVM_EXECUTIONENGINE_ORC_ORCREMOTETARGETCLIENT_H
  17 #define LLVM_EXECUTIONENGINE_ORC_ORCREMOTETARGETCLIENT_H
  18
  19 #include "IndirectionUtils.h"
  20 #include "OrcRemoteTargetRPCAPI.h"
  21
  22 #define DEBUG_TYPE "orc-remote"
  23
  24 namespace llvm {
  25 namespace orc {
  26 namespace remote {
  27
  28 /// This class provides utilities (including memory manager, indirect stubs
  29 /// manager, and compile callback manager types) that support remote JITing
  30 /// in ORC.
  31 ///
  32 /// Each of the utility classes talks to a JIT server (an instance of the
  33 /// OrcRemoteTargetServer class) via an RPC system (see RPCUtils.h) to carry out
  34 /// its actions.
  35 template <typename ChannelT>
  36 class OrcRemoteTargetClient : public OrcRemoteTargetRPCAPI {
  37 public:
  38   /// Remote memory manager.
  39   class RCMemoryManager : public RuntimeDyld::MemoryManager {
  40   public:
  41     RCMemoryManager(OrcRemoteTargetClient &Client, ResourceIdMgr::ResourceId Id)
  42         : Client(Client), Id(Id) {
  43       DEBUG(dbgs() << "Created remote allocator " << Id << "\n");
  44     }
  45
  46     ~RCMemoryManager() {
  47       Client.destroyRemoteAllocator(Id);
  48       DEBUG(dbgs() << "Destroyed remote allocator " << Id << "\n");
  49     }
  50
  51     uint8_t *allocateCodeSection(uintptr_t Size, unsigned Alignment,
  52                                  unsigned SectionID,
  53                                  StringRef SectionName) override {
  54       Unmapped.back().CodeAllocs.emplace_back(Size, Alignment);
  55       uint8_t *Alloc = reinterpret_cast<uint8_t *>(
  56           Unmapped.back().CodeAllocs.back().getLocalAddress());
  57       DEBUG(dbgs() << "Allocator " << Id << " allocated code for "
  58                    << SectionName << ": " << Alloc << " (" << Size
  59                    << " bytes, alignment " << Alignment << ")\n");
  60       return Alloc;
  61     }
  62
  63     uint8_t *allocateDataSection(uintptr_t Size, unsigned Alignment,
  64                                  unsigned SectionID, StringRef SectionName,
  65                                  bool IsReadOnly) override {
  66       if (IsReadOnly) {
  67         Unmapped.back().RODataAllocs.emplace_back(Size, Alignment);
  68         uint8_t *Alloc = reinterpret_cast<uint8_t *>(
  69             Unmapped.back().RODataAllocs.back().getLocalAddress());
  70         DEBUG(dbgs() << "Allocator " << Id << " allocated ro-data for "
  71                      << SectionName << ": " << Alloc << " (" << Size
  72                      << " bytes, alignment " << Alignment << ")\n");
  73         return Alloc;
  74       } // else...
  75
  76       Unmapped.back().RWDataAllocs.emplace_back(Size, Alignment);
  77       uint8_t *Alloc = reinterpret_cast<uint8_t *>(
  78           Unmapped.back().RWDataAllocs.back().getLocalAddress());
  79       DEBUG(dbgs() << "Allocator " << Id << " allocated rw-data for "
  80                    << SectionName << ": " << Alloc << " (" << Size
  81                    << " bytes, alignment " << Alignment << "\n");
  82       return Alloc;
  83     }
  84
  85     void reserveAllocationSpace(uintptr_t CodeSize, uint32_t CodeAlign,
  86                                 uintptr_t RODataSize, uint32_t RODataAlign,
  87                                 uintptr_t RWDataSize,
  88                                 uint32_t RWDataAlign) override {
  89       Unmapped.push_back(ObjectAllocs());
  90
  91       DEBUG(dbgs() << "Allocator " << Id << " reserved:\n");
  92
  93       if (CodeSize != 0) {
  94         if (std::error_code EC = Client.reserveMem(
  95                 Unmapped.back().RemoteCodeAddr, Id, CodeSize, CodeAlign)) {
  96           (void)EC;
  97           // FIXME; Add error to poll.
  98           llvm_unreachable("Failed reserving remote memory.");
  99         }
 100         DEBUG(dbgs() << "  code: "
 101                      << format("0x%016x", Unmapped.back().RemoteCodeAddr)
 102                      << " (" << CodeSize << " bytes, alignment " << CodeAlign
 103                      << ")\n");
 104       }
 105
 106       if (RODataSize != 0) {
 107         if (auto EC = Client.reserveMem(Unmapped.back().RemoteRODataAddr, Id,
 108                                         RODataSize, RODataAlign)) {
 109           // FIXME; Add error to poll.
 110           llvm_unreachable("Failed reserving remote memory.");
 111         }
 112         DEBUG(dbgs() << "  ro-data: "
 113                      << format("0x%016x", Unmapped.back().RemoteRODataAddr)
 114                      << " (" << RODataSize << " bytes, alignment "
 115                      << RODataAlign << ")\n");
 116       }
 117
 118       if (RWDataSize != 0) {
 119         if (auto EC = Client.reserveMem(Unmapped.back().RemoteRWDataAddr, Id,
 120                                         RWDataSize, RWDataAlign)) {
 121           // FIXME; Add error to poll.
 122           llvm_unreachable("Failed reserving remote memory.");
 123         }
 124         DEBUG(dbgs() << "  rw-data: "
 125                      << format("0x%016x", Unmapped.back().RemoteRWDataAddr)
 126                      << " (" << RWDataSize << " bytes, alignment "
 127                      << RWDataAlign << ")\n");
 128       }
 129     }
 130
 131     bool needsToReserveAllocationSpace() override { return true; }
 132
 133     void registerEHFrames(uint8_t *Addr, uint64_t LoadAddr,
 134                           size_t Size) override {}
 135
 136     void deregisterEHFrames(uint8_t *addr, uint64_t LoadAddr,
 137                             size_t Size) override {}
 138
 139     void notifyObjectLoaded(RuntimeDyld &Dyld,
 140                             const object::ObjectFile &Obj) override {
 141       DEBUG(dbgs() << "Allocator " << Id << " applied mappings:\n");
 142       for (auto &ObjAllocs : Unmapped) {
 143         {
 144           TargetAddress NextCodeAddr = ObjAllocs.RemoteCodeAddr;
 145           for (auto &Alloc : ObjAllocs.CodeAllocs) {
 146             NextCodeAddr = RoundUpToAlignment(NextCodeAddr, Alloc.getAlign());
 147             Dyld.mapSectionAddress(Alloc.getLocalAddress(), NextCodeAddr);
 148             DEBUG(dbgs() << "     code: "
 149                          << static_cast<void *>(Alloc.getLocalAddress())
 150                          << " -> " << format("0x%016x", NextCodeAddr) << "\n");
 151             Alloc.setRemoteAddress(NextCodeAddr);
 152             NextCodeAddr += Alloc.getSize();
 153           }
 154         }
 155         {
 156           TargetAddress NextRODataAddr = ObjAllocs.RemoteRODataAddr;
 157           for (auto &Alloc : ObjAllocs.RODataAllocs) {
 158             NextRODataAddr =
 159                 RoundUpToAlignment(NextRODataAddr, Alloc.getAlign());
 160             Dyld.mapSectionAddress(Alloc.getLocalAddress(), NextRODataAddr);
 161             DEBUG(dbgs() << "  ro-data: "
 162                          << static_cast<void *>(Alloc.getLocalAddress())
 163                          << " -> " << format("0x%016x", NextRODataAddr)
 164                          << "\n");
 165             Alloc.setRemoteAddress(NextRODataAddr);
 166             NextRODataAddr += Alloc.getSize();
 167           }
 168         }
 169         {
 170           TargetAddress NextRWDataAddr = ObjAllocs.RemoteRWDataAddr;
 171           for (auto &Alloc : ObjAllocs.RWDataAllocs) {
 172             NextRWDataAddr =
 173                 RoundUpToAlignment(NextRWDataAddr, Alloc.getAlign());
 174             Dyld.mapSectionAddress(Alloc.getLocalAddress(), NextRWDataAddr);
 175             DEBUG(dbgs() << "  rw-data: "
 176                          << static_cast<void *>(Alloc.getLocalAddress())
 177                          << " -> " << format("0x%016x", NextRWDataAddr)
 178                          << "\n");
 179             Alloc.setRemoteAddress(NextRWDataAddr);
 180             NextRWDataAddr += Alloc.getSize();
 181           }
 182         }
 183         Unfinalized.push_back(std::move(ObjAllocs));
 184       }
 185       Unmapped.clear();
 186     }
 187
 188     bool finalizeMemory(std::string *ErrMsg = nullptr) override {
 189       DEBUG(dbgs() << "Allocator " << Id << " finalizing:\n");
 190
 191       for (auto &ObjAllocs : Unfinalized) {
 192
 193         for (auto &Alloc : ObjAllocs.CodeAllocs) {
 194           DEBUG(dbgs() << "  copying code: "
 195                        << static_cast<void *>(Alloc.getLocalAddress()) << " -> "
 196                        << format("0x%016x", Alloc.getRemoteAddress()) << " ("
 197                        << Alloc.getSize() << " bytes)\n");
 198           Client.writeMem(Alloc.getRemoteAddress(), Alloc.getLocalAddress(),
 199                           Alloc.getSize());
 200         }
 201
 202         if (ObjAllocs.RemoteCodeAddr) {
 203           DEBUG(dbgs() << "  setting R-X permissions on code block: "
 204                        << format("0x%016x", ObjAllocs.RemoteCodeAddr) << "\n");
 205           Client.setProtections(Id, ObjAllocs.RemoteCodeAddr,
 206                                 sys::Memory::MF_READ | sys::Memory::MF_EXEC);
 207         }
 208
 209         for (auto &Alloc : ObjAllocs.RODataAllocs) {
 210           DEBUG(dbgs() << "  copying ro-data: "
 211                        << static_cast<void *>(Alloc.getLocalAddress()) << " -> "
 212                        << format("0x%016x", Alloc.getRemoteAddress()) << " ("
 213                        << Alloc.getSize() << " bytes)\n");
 214           Client.writeMem(Alloc.getRemoteAddress(), Alloc.getLocalAddress(),
 215                           Alloc.getSize());
 216         }
 217
 218         if (ObjAllocs.RemoteRODataAddr) {
 219           DEBUG(dbgs() << "  setting R-- permissions on ro-data block: "
 220                        << format("0x%016x", ObjAllocs.RemoteRODataAddr)
 221                        << "\n");
 222           Client.setProtections(Id, ObjAllocs.RemoteRODataAddr,
 223                                 sys::Memory::MF_READ);
 224         }
 225
 226         for (auto &Alloc : ObjAllocs.RWDataAllocs) {
 227           DEBUG(dbgs() << "  copying rw-data: "
 228                        << static_cast<void *>(Alloc.getLocalAddress()) << " -> "
 229                        << format("0x%016x", Alloc.getRemoteAddress()) << " ("
 230                        << Alloc.getSize() << " bytes)\n");
 231           Client.writeMem(Alloc.getRemoteAddress(), Alloc.getLocalAddress(),
 232                           Alloc.getSize());
 233         }
 234
 235         if (ObjAllocs.RemoteRWDataAddr) {
 236           DEBUG(dbgs() << "  setting RW- permissions on rw-data block: "
 237                        << format("0x%016x", ObjAllocs.RemoteRWDataAddr)
 238                        << "\n");
 239           Client.setProtections(Id, ObjAllocs.RemoteRWDataAddr,
 240                                 sys::Memory::MF_READ | sys::Memory::MF_WRITE);
 241         }
 242       }
 243       Unfinalized.clear();
 244
 245       return false;
 246     }
 247
 248   private:
 249     class Alloc {
 250     public:
 251       Alloc(uint64_t Size, unsigned Align)
 252           : Size(Size), Align(Align), Contents(new char[Size + Align - 1]),
 253             RemoteAddr(0) {}
 254
 255       uint64_t getSize() const { return Size; }
 256
 257       unsigned getAlign() const { return Align; }
 258
 259       char *getLocalAddress() const {
 260         uintptr_t LocalAddr = reinterpret_cast<uintptr_t>(Contents.get());
 261         LocalAddr = RoundUpToAlignment(LocalAddr, Align);
 262         return reinterpret_cast<char *>(LocalAddr);
 263       }
 264
 265       void setRemoteAddress(TargetAddress RemoteAddr) {
 266         this->RemoteAddr = RemoteAddr;
 267       }
 268
 269       TargetAddress getRemoteAddress() const { return RemoteAddr; }
 270
 271     private:
 272       uint64_t Size;
 273       unsigned Align;
 274       std::unique_ptr<char[]> Contents;
 275       TargetAddress RemoteAddr;
 276     };
 277
 278     struct ObjectAllocs {
 279       ObjectAllocs()
 280           : RemoteCodeAddr(0), RemoteRODataAddr(0), RemoteRWDataAddr(0) {}
 281       TargetAddress RemoteCodeAddr;
 282       TargetAddress RemoteRODataAddr;
 283       TargetAddress RemoteRWDataAddr;
 284       std::vector<Alloc> CodeAllocs, RODataAllocs, RWDataAllocs;
 285     };
 286
 287     OrcRemoteTargetClient &Client;
 288     ResourceIdMgr::ResourceId Id;
 289     std::vector<ObjectAllocs> Unmapped;
 290     std::vector<ObjectAllocs> Unfinalized;
 291   };
 292
 293   /// Remote indirect stubs manager.
 294   class RCIndirectStubsManager : public IndirectStubsManager {
 295   public:
 296     RCIndirectStubsManager(OrcRemoteTargetClient &Remote,
 297                            ResourceIdMgr::ResourceId Id)
 298         : Remote(Remote), Id(Id) {}
 299
 300     ~RCIndirectStubsManager() { Remote.destroyIndirectStubsManager(Id); }
 301
 302     std::error_code createStub(StringRef StubName, TargetAddress StubAddr,
 303                                JITSymbolFlags StubFlags) override {
 304       if (auto EC = reserveStubs(1))
 305         return EC;
 306
 307       return createStubInternal(StubName, StubAddr, StubFlags);
 308     }
 309
 310     std::error_code createStubs(const StubInitsMap &StubInits) override {
 311       if (auto EC = reserveStubs(StubInits.size()))
 312         return EC;
 313
 314       for (auto &Entry : StubInits)
 315         if (auto EC = createStubInternal(Entry.first(), Entry.second.first,
 316                                          Entry.second.second))
 317           return EC;
 318
 319       return std::error_code();
 320     }
 321
 322     JITSymbol findStub(StringRef Name, bool ExportedStubsOnly) override {
 323       auto I = StubIndexes.find(Name);
 324       if (I == StubIndexes.end())
 325         return nullptr;
 326       auto Key = I->second.first;
 327       auto Flags = I->second.second;
 328       auto StubSymbol = JITSymbol(getStubAddr(Key), Flags);
 329       if (ExportedStubsOnly && !StubSymbol.isExported())
 330         return nullptr;
 331       return StubSymbol;
 332     }
 333
 334     JITSymbol findPointer(StringRef Name) override {
 335       auto I = StubIndexes.find(Name);
 336       if (I == StubIndexes.end())
 337         return nullptr;
 338       auto Key = I->second.first;
 339       auto Flags = I->second.second;
 340       return JITSymbol(getPtrAddr(Key), Flags);
 341     }
 342
 343     std::error_code updatePointer(StringRef Name,
 344                                   TargetAddress NewAddr) override {
 345       auto I = StubIndexes.find(Name);
 346       assert(I != StubIndexes.end() && "No stub pointer for symbol");
 347       auto Key = I->second.first;
 348       return Remote.writePointer(getPtrAddr(Key), NewAddr);
 349     }
 350
 351   private:
 352     struct RemoteIndirectStubsInfo {
 353       RemoteIndirectStubsInfo(TargetAddress StubBase, TargetAddress PtrBase,
 354                               unsigned NumStubs)
 355           : StubBase(StubBase), PtrBase(PtrBase), NumStubs(NumStubs) {}
 356       TargetAddress StubBase;
 357       TargetAddress PtrBase;
 358       unsigned NumStubs;
 359     };
 360
 361     OrcRemoteTargetClient &Remote;
 362     ResourceIdMgr::ResourceId Id;
 363     std::vector<RemoteIndirectStubsInfo> RemoteIndirectStubsInfos;
 364     typedef std::pair<uint16_t, uint16_t> StubKey;
 365     std::vector<StubKey> FreeStubs;
 366     StringMap<std::pair<StubKey, JITSymbolFlags>> StubIndexes;
 367
 368     std::error_code reserveStubs(unsigned NumStubs) {
 369       if (NumStubs <= FreeStubs.size())
 370         return std::error_code();
 371
 372       unsigned NewStubsRequired = NumStubs - FreeStubs.size();
 373       TargetAddress StubBase;
 374       TargetAddress PtrBase;
 375       unsigned NumStubsEmitted;
 376
 377       Remote.emitIndirectStubs(StubBase, PtrBase, NumStubsEmitted, Id,
 378                                NewStubsRequired);
 379
 380       unsigned NewBlockId = RemoteIndirectStubsInfos.size();
 381       RemoteIndirectStubsInfos.push_back(
 382           RemoteIndirectStubsInfo(StubBase, PtrBase, NumStubsEmitted));
 383
 384       for (unsigned I = 0; I < NumStubsEmitted; ++I)
 385         FreeStubs.push_back(std::make_pair(NewBlockId, I));
 386
 387       return std::error_code();
 388     }
 389
 390     std::error_code createStubInternal(StringRef StubName,
 391                                        TargetAddress InitAddr,
 392                                        JITSymbolFlags StubFlags) {
 393       auto Key = FreeStubs.back();
 394       FreeStubs.pop_back();
 395       StubIndexes[StubName] = std::make_pair(Key, StubFlags);
 396       return Remote.writePointer(getPtrAddr(Key), InitAddr);
 397     }
 398
 399     TargetAddress getStubAddr(StubKey K) {
 400       assert(RemoteIndirectStubsInfos[K.first].StubBase != 0 &&
 401              "Missing stub address");
 402       return RemoteIndirectStubsInfos[K.first].StubBase +
 403              K.second * Remote.getIndirectStubSize();
 404     }
 405
 406     TargetAddress getPtrAddr(StubKey K) {
 407       assert(RemoteIndirectStubsInfos[K.first].PtrBase != 0 &&
 408              "Missing pointer address");
 409       return RemoteIndirectStubsInfos[K.first].PtrBase +
 410              K.second * Remote.getPointerSize();
 411     }
 412   };
 413
 414   /// Remote compile callback manager.
 415   class RCCompileCallbackManager : public JITCompileCallbackManager {
 416   public:
 417     RCCompileCallbackManager(TargetAddress ErrorHandlerAddress,
 418                              OrcRemoteTargetClient &Remote)
 419         : JITCompileCallbackManager(ErrorHandlerAddress), Remote(Remote) {
 420       assert(!Remote.CompileCallback && "Compile callback already set");
 421       Remote.CompileCallback = [this](TargetAddress TrampolineAddr) {
 422         return executeCompileCallback(TrampolineAddr);
 423       };
 424       Remote.emitResolverBlock();
 425     }
 426
 427   private:
 428     void grow() {
 429       TargetAddress BlockAddr = 0;
 430       uint32_t NumTrampolines = 0;
 431       auto EC = Remote.emitTrampolineBlock(BlockAddr, NumTrampolines);
 432       assert(!EC && "Failed to create trampolines");
 433
 434       uint32_t TrampolineSize = Remote.getTrampolineSize();
 435       for (unsigned I = 0; I < NumTrampolines; ++I)
 436         this->AvailableTrampolines.push_back(BlockAddr + (I * TrampolineSize));
 437     }
 438
 439     OrcRemoteTargetClient &Remote;
 440   };
 441
 442   /// Create an OrcRemoteTargetClient.
 443   /// Channel is the ChannelT instance to communicate on. It is assumed that
 444   /// the channel is ready to be read from and written to.
 445   static ErrorOr<OrcRemoteTargetClient> Create(ChannelT &Channel) {
 446     std::error_code EC;
 447     OrcRemoteTargetClient H(Channel, EC);
 448     if (EC)
 449       return EC;
 450     return H;
 451   }
 452
 453   /// Call the int(void) function at the given address in the target and return
 454   /// its result.
 455   std::error_code callIntVoid(int &Result, TargetAddress Addr) {
 456     DEBUG(dbgs() << "Calling int(*)(void) " << format("0x%016x", Addr) << "\n");
 457
 458     if (auto EC = call<CallIntVoid>(Channel, Addr))
 459       return EC;
 460
 461     unsigned NextProcId;
 462     if (auto EC = listenForCompileRequests(NextProcId))
 463       return EC;
 464
 465     if (NextProcId != CallIntVoidResponseId)
 466       return orcError(OrcErrorCode::UnexpectedRPCCall);
 467
 468     return handle<CallIntVoidResponse>(Channel, [&](int R) {
 469       Result = R;
 470       DEBUG(dbgs() << "Result: " << R << "\n");
 471       return std::error_code();
 472     });
 473   }
 474
 475   /// Call the int(int, char*[]) function at the given address in the target and
 476   /// return its result.
 477   std::error_code callMain(int &Result, TargetAddress Addr,
 478                            const std::vector<std::string> &Args) {
 479     DEBUG(dbgs() << "Calling int(*)(int, char*[]) " << format("0x%016x", Addr)
 480                  << "\n");
 481
 482     if (auto EC = call<CallMain>(Channel, Addr, Args))
 483       return EC;
 484
 485     unsigned NextProcId;
 486     if (auto EC = listenForCompileRequests(NextProcId))
 487       return EC;
 488
 489     if (NextProcId != CallMainResponseId)
 490       return orcError(OrcErrorCode::UnexpectedRPCCall);
 491
 492     return handle<CallMainResponse>(Channel, [&](int R) {
 493       Result = R;
 494       DEBUG(dbgs() << "Result: " << R << "\n");
 495       return std::error_code();
 496     });
 497   }
 498
 499   /// Call the void() function at the given address in the target and wait for
 500   /// it to finish.
 501   std::error_code callVoidVoid(TargetAddress Addr) {
 502     DEBUG(dbgs() << "Calling void(*)(void) " << format("0x%016x", Addr)
 503                  << "\n");
 504
 505     if (auto EC = call<CallVoidVoid>(Channel, Addr))
 506       return EC;
 507
 508     unsigned NextProcId;
 509     if (auto EC = listenForCompileRequests(NextProcId))
 510       return EC;
 511
 512     if (NextProcId != CallVoidVoidResponseId)
 513       return orcError(OrcErrorCode::UnexpectedRPCCall);
 514
 515     return handle<CallVoidVoidResponse>(Channel, doNothing);
 516   }
 517
 518   /// Create an RCMemoryManager which will allocate its memory on the remote
 519   /// target.
 520   std::error_code
 521   createRemoteMemoryManager(std::unique_ptr<RCMemoryManager> &MM) {
 522     assert(!MM && "MemoryManager should be null before creation.");
 523
 524     auto Id = AllocatorIds.getNext();
 525     if (auto EC = call<CreateRemoteAllocator>(Channel, Id))
 526       return EC;
 527     MM = llvm::make_unique<RCMemoryManager>(*this, Id);
 528     return std::error_code();
 529   }
 530
 531   /// Create an RCIndirectStubsManager that will allocate stubs on the remote
 532   /// target.
 533   std::error_code
 534   createIndirectStubsManager(std::unique_ptr<RCIndirectStubsManager> &I) {
 535     assert(!I && "Indirect stubs manager should be null before creation.");
 536     auto Id = IndirectStubOwnerIds.getNext();
 537     if (auto EC = call<CreateIndirectStubsOwner>(Channel, Id))
 538       return EC;
 539     I = llvm::make_unique<RCIndirectStubsManager>(*this, Id);
 540     return std::error_code();
 541   }
 542
 543   /// Search for symbols in the remote process. Note: This should be used by
 544   /// symbol resolvers *after* they've searched the local symbol table in the
 545   /// JIT stack.
 546   std::error_code getSymbolAddress(TargetAddress &Addr, StringRef Name) {
 547     // Check for an 'out-of-band' error, e.g. from an MM destructor.
 548     if (ExistingError)
 549       return ExistingError;
 550
 551     // Request remote symbol address.
 552     if (auto EC = call<GetSymbolAddress>(Channel, Name))
 553       return EC;
 554
 555     return expect<GetSymbolAddressResponse>(Channel, [&](TargetAddress &A) {
 556       Addr = A;
 557       DEBUG(dbgs() << "Remote address lookup " << Name << " = "
 558                    << format("0x%016x", Addr) << "\n");
 559       return std::error_code();
 560     });
 561   }
 562
 563   /// Get the triple for the remote target.
 564   const std::string &getTargetTriple() const { return RemoteTargetTriple; }
 565
 566   std::error_code terminateSession() { return call<TerminateSession>(Channel); }
 567
 568 private:
 569   OrcRemoteTargetClient(ChannelT &Channel, std::error_code &EC)
 570       : Channel(Channel), RemotePointerSize(0), RemotePageSize(0),
 571         RemoteTrampolineSize(0), RemoteIndirectStubSize(0) {
 572     if ((EC = call<GetRemoteInfo>(Channel)))
 573       return;
 574
 575     EC = expect<GetRemoteInfoResponse>(
 576         Channel, readArgs(RemoteTargetTriple, RemotePointerSize, RemotePageSize,
 577                           RemoteTrampolineSize, RemoteIndirectStubSize));
 578   }
 579
 580   void destroyRemoteAllocator(ResourceIdMgr::ResourceId Id) {
 581     if (auto EC = call<DestroyRemoteAllocator>(Channel, Id)) {
 582       // FIXME: This will be triggered by a removeModuleSet call: Propagate
 583       //        error return up through that.
 584       llvm_unreachable("Failed to destroy remote allocator.");
 585       AllocatorIds.release(Id);
 586     }
 587   }
 588
 589   std::error_code destroyIndirectStubsManager(ResourceIdMgr::ResourceId Id) {
 590     IndirectStubOwnerIds.release(Id);
 591     return call<DestroyIndirectStubsOwner>(Channel, Id);
 592   }
 593
 594   std::error_code emitIndirectStubs(TargetAddress &StubBase,
 595                                     TargetAddress &PtrBase,
 596                                     uint32_t &NumStubsEmitted,
 597                                     ResourceIdMgr::ResourceId Id,
 598                                     uint32_t NumStubsRequired) {
 599     if (auto EC = call<EmitIndirectStubs>(Channel, Id, NumStubsRequired))
 600       return EC;
 601
 602     return expect<EmitIndirectStubsResponse>(
 603         Channel, readArgs(StubBase, PtrBase, NumStubsEmitted));
 604   }
 605
 606   std::error_code emitResolverBlock() {
 607     // Check for an 'out-of-band' error, e.g. from an MM destructor.
 608     if (ExistingError)
 609       return ExistingError;
 610
 611     return call<EmitResolverBlock>(Channel);
 612   }
 613
 614   std::error_code emitTrampolineBlock(TargetAddress &BlockAddr,
 615                                       uint32_t &NumTrampolines) {
 616     // Check for an 'out-of-band' error, e.g. from an MM destructor.
 617     if (ExistingError)
 618       return ExistingError;
 619
 620     if (auto EC = call<EmitTrampolineBlock>(Channel))
 621       return EC;
 622
 623     return expect<EmitTrampolineBlockResponse>(
 624         Channel, [&](TargetAddress BAddr, uint32_t NTrampolines) {
 625           BlockAddr = BAddr;
 626           NumTrampolines = NTrampolines;
 627           return std::error_code();
 628         });
 629   }
 630
 631   uint32_t getIndirectStubSize() const { return RemoteIndirectStubSize; }
 632   uint32_t getPageSize() const { return RemotePageSize; }
 633   uint32_t getPointerSize() const { return RemotePointerSize; }
 634
 635   uint32_t getTrampolineSize() const { return RemoteTrampolineSize; }
 636
 637   std::error_code listenForCompileRequests(uint32_t &NextId) {
 638     // Check for an 'out-of-band' error, e.g. from an MM destructor.
 639     if (ExistingError)
 640       return ExistingError;
 641
 642     if (auto EC = getNextProcId(Channel, NextId))
 643       return EC;
 644
 645     while (NextId == RequestCompileId) {
 646       TargetAddress TrampolineAddr = 0;
 647       if (auto EC = handle<RequestCompile>(Channel, readArgs(TrampolineAddr)))
 648         return EC;
 649
 650       TargetAddress ImplAddr = CompileCallback(TrampolineAddr);
 651       if (auto EC = call<RequestCompileResponse>(Channel, ImplAddr))
 652         return EC;
 653
 654       if (auto EC = getNextProcId(Channel, NextId))
 655         return EC;
 656     }
 657
 658     return std::error_code();
 659   }
 660
 661   std::error_code readMem(char *Dst, TargetAddress Src, uint64_t Size) {
 662     // Check for an 'out-of-band' error, e.g. from an MM destructor.
 663     if (ExistingError)
 664       return ExistingError;
 665
 666     if (auto EC = call<ReadMem>(Channel, Src, Size))
 667       return EC;
 668
 669     if (auto EC = expect<ReadMemResponse>(
 670             Channel, [&]() { return Channel.readBytes(Dst, Size); }))
 671       return EC;
 672
 673     return std::error_code();
 674   }
 675
 676   std::error_code reserveMem(TargetAddress &RemoteAddr,
 677                              ResourceIdMgr::ResourceId Id, uint64_t Size,
 678                              uint32_t Align) {
 679
 680     // Check for an 'out-of-band' error, e.g. from an MM destructor.
 681     if (ExistingError)
 682       return ExistingError;
 683
 684     if (auto EC = call<ReserveMem>(Channel, Id, Size, Align))
 685       return EC;
 686
 687     if (auto EC = expect<ReserveMemResponse>(Channel, [&](TargetAddress Addr) {
 688           RemoteAddr = Addr;
 689           return std::error_code();
 690         }))
 691       return EC;
 692
 693     return std::error_code();
 694   }
 695
 696   std::error_code setProtections(ResourceIdMgr::ResourceId Id,
 697                                  TargetAddress RemoteSegAddr,
 698                                  unsigned ProtFlags) {
 699     return call<SetProtections>(Channel, Id, RemoteSegAddr, ProtFlags);
 700   }
 701
 702   std::error_code writeMem(TargetAddress Addr, const char *Src, uint64_t Size) {
 703     // Check for an 'out-of-band' error, e.g. from an MM destructor.
 704     if (ExistingError)
 705       return ExistingError;
 706
 707     // Make the send call.
 708     if (auto EC = call<WriteMem>(Channel, Addr, Size))
 709       return EC;
 710
 711     // Follow this up with the section contents.
 712     if (auto EC = Channel.appendBytes(Src, Size))
 713       return EC;
 714
 715     return Channel.send();
 716   }
 717
 718   std::error_code writePointer(TargetAddress Addr, TargetAddress PtrVal) {
 719     // Check for an 'out-of-band' error, e.g. from an MM destructor.
 720     if (ExistingError)
 721       return ExistingError;
 722
 723     return call<WritePtr>(Channel, Addr, PtrVal);
 724   }
 725
 726   static std::error_code doNothing() { return std::error_code(); }
 727
 728   ChannelT &Channel;
 729   std::error_code ExistingError;
 730   std::string RemoteTargetTriple;
 731   uint32_t RemotePointerSize;
 732   uint32_t RemotePageSize;
 733   uint32_t RemoteTrampolineSize;
 734   uint32_t RemoteIndirectStubSize;
 735   ResourceIdMgr AllocatorIds, IndirectStubOwnerIds;
 736   std::function<TargetAddress(TargetAddress)> CompileCallback;
 737 };
 738
 739 } // end namespace remote
 740 } // end namespace orc
 741 } // end namespace llvm
 742
 743 #undef DEBUG_TYPE
 744
 745 #endif