LCOV - code coverage report
Current view: top level - lib/ExecutionEngine/RuntimeDyld - RuntimeDyld.cpp (source / functions) Hit Total Coverage
Test: llvm-toolchain.info Lines: 401 464 86.4 %
Date: 2018-02-20 03:34:22 Functions: 35 50 70.0 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : //===-- RuntimeDyld.cpp - Run-time dynamic linker for MC-JIT ----*- 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             : // Implementation of the MC-JIT runtime dynamic linker.
      11             : //
      12             : //===----------------------------------------------------------------------===//
      13             : 
      14             : #include "llvm/ExecutionEngine/RuntimeDyld.h"
      15             : #include "RuntimeDyldCOFF.h"
      16             : #include "RuntimeDyldCheckerImpl.h"
      17             : #include "RuntimeDyldELF.h"
      18             : #include "RuntimeDyldImpl.h"
      19             : #include "RuntimeDyldMachO.h"
      20             : #include "llvm/Object/COFF.h"
      21             : #include "llvm/Object/ELFObjectFile.h"
      22             : #include "llvm/Support/ManagedStatic.h"
      23             : #include "llvm/Support/MathExtras.h"
      24             : #include "llvm/Support/MutexGuard.h"
      25             : 
      26             : using namespace llvm;
      27             : using namespace llvm::object;
      28             : 
      29             : #define DEBUG_TYPE "dyld"
      30             : 
      31             : namespace {
      32             : 
      33             : enum RuntimeDyldErrorCode {
      34             :   GenericRTDyldError = 1
      35             : };
      36             : 
      37             : // FIXME: This class is only here to support the transition to llvm::Error. It
      38             : // will be removed once this transition is complete. Clients should prefer to
      39             : // deal with the Error value directly, rather than converting to error_code.
      40           0 : class RuntimeDyldErrorCategory : public std::error_category {
      41             : public:
      42           0 :   const char *name() const noexcept override { return "runtimedyld"; }
      43             : 
      44           0 :   std::string message(int Condition) const override {
      45           0 :     switch (static_cast<RuntimeDyldErrorCode>(Condition)) {
      46           0 :       case GenericRTDyldError: return "Generic RuntimeDyld error";
      47             :     }
      48           0 :     llvm_unreachable("Unrecognized RuntimeDyldErrorCode");
      49             :   }
      50             : };
      51             : 
      52             : static ManagedStatic<RuntimeDyldErrorCategory> RTDyldErrorCategory;
      53             : 
      54             : }
      55             : 
      56             : char RuntimeDyldError::ID = 0;
      57             : 
      58           0 : void RuntimeDyldError::log(raw_ostream &OS) const {
      59           0 :   OS << ErrMsg << "\n";
      60           0 : }
      61             : 
      62           0 : std::error_code RuntimeDyldError::convertToErrorCode() const {
      63           0 :   return std::error_code(GenericRTDyldError, *RTDyldErrorCategory);
      64             : }
      65             : 
      66             : // Empty out-of-line virtual destructor as the key function.
      67         681 : RuntimeDyldImpl::~RuntimeDyldImpl() {}
      68             : 
      69             : // Pin LoadedObjectInfo's vtables to this file.
      70           0 : void RuntimeDyld::LoadedObjectInfo::anchor() {}
      71             : 
      72             : namespace llvm {
      73             : 
      74           0 : void RuntimeDyldImpl::registerEHFrames() {}
      75             : 
      76          64 : void RuntimeDyldImpl::deregisterEHFrames() {
      77          64 :   MemMgr.deregisterEHFrames();
      78          64 : }
      79             : 
      80             : #ifndef NDEBUG
      81             : static void dumpSectionMemory(const SectionEntry &S, StringRef State) {
      82             :   dbgs() << "----- Contents of section " << S.getName() << " " << State
      83             :          << " -----";
      84             : 
      85             :   if (S.getAddress() == nullptr) {
      86             :     dbgs() << "\n          <section not emitted>\n";
      87             :     return;
      88             :   }
      89             : 
      90             :   const unsigned ColsPerRow = 16;
      91             : 
      92             :   uint8_t *DataAddr = S.getAddress();
      93             :   uint64_t LoadAddr = S.getLoadAddress();
      94             : 
      95             :   unsigned StartPadding = LoadAddr & (ColsPerRow - 1);
      96             :   unsigned BytesRemaining = S.getSize();
      97             : 
      98             :   if (StartPadding) {
      99             :     dbgs() << "\n" << format("0x%016" PRIx64,
     100             :                              LoadAddr & ~(uint64_t)(ColsPerRow - 1)) << ":";
     101             :     while (StartPadding--)
     102             :       dbgs() << "   ";
     103             :   }
     104             : 
     105             :   while (BytesRemaining > 0) {
     106             :     if ((LoadAddr & (ColsPerRow - 1)) == 0)
     107             :       dbgs() << "\n" << format("0x%016" PRIx64, LoadAddr) << ":";
     108             : 
     109             :     dbgs() << " " << format("%02x", *DataAddr);
     110             : 
     111             :     ++DataAddr;
     112             :     ++LoadAddr;
     113             :     --BytesRemaining;
     114             :   }
     115             : 
     116             :   dbgs() << "\n";
     117             : }
     118             : #endif
     119             : 
     120             : // Resolve the relocations for all symbols we currently know about.
     121         476 : void RuntimeDyldImpl::resolveRelocations() {
     122             :   MutexGuard locked(lock);
     123             : 
     124             :   // Print out the sections prior to relocation.
     125             :   DEBUG(
     126             :     for (int i = 0, e = Sections.size(); i != e; ++i)
     127             :       dumpSectionMemory(Sections[i], "before relocations");
     128             :   );
     129             : 
     130             :   // First, resolve relocations associated with external symbols.
     131         952 :   if (auto Err = resolveExternalSymbols()) {
     132           0 :     HasError = true;
     133           0 :     ErrorStr = toString(std::move(Err));
     134             :   }
     135             : 
     136             :   // Iterate over all outstanding relocations
     137        1006 :   for (auto it = Relocations.begin(), e = Relocations.end(); it != e; ++it) {
     138             :     // The Section here (Sections[i]) refers to the section in which the
     139             :     // symbol for the relocation is located.  The SectionID in the relocation
     140             :     // entry provides the section to which the relocation will be applied.
     141         530 :     int Idx = it->first;
     142        1060 :     uint64_t Addr = Sections[Idx].getLoadAddress();
     143             :     DEBUG(dbgs() << "Resolving relocations Section #" << Idx << "\t"
     144             :                  << format("%p", (uintptr_t)Addr) << "\n");
     145         530 :     resolveRelocationList(it->second, Addr);
     146             :   }
     147             :   Relocations.clear();
     148             : 
     149             :   // Print out sections after relocation.
     150             :   DEBUG(
     151             :     for (int i = 0, e = Sections.size(); i != e; ++i)
     152             :       dumpSectionMemory(Sections[i], "after relocations");
     153             :   );
     154             : 
     155         476 : }
     156             : 
     157         194 : void RuntimeDyldImpl::mapSectionAddress(const void *LocalAddress,
     158             :                                         uint64_t TargetAddress) {
     159             :   MutexGuard locked(lock);
     160         507 :   for (unsigned i = 0, e = Sections.size(); i != e; ++i) {
     161        1014 :     if (Sections[i].getAddress() == LocalAddress) {
     162         194 :       reassignSectionAddress(i, TargetAddress);
     163         194 :       return;
     164             :     }
     165             :   }
     166           0 :   llvm_unreachable("Attempting to remap address of unknown section!");
     167             : }
     168             : 
     169         824 : static Error getOffset(const SymbolRef &Sym, SectionRef Sec,
     170             :                        uint64_t &Result) {
     171             :   Expected<uint64_t> AddressOrErr = Sym.getAddress();
     172         824 :   if (!AddressOrErr)
     173             :     return AddressOrErr.takeError();
     174        1648 :   Result = *AddressOrErr - Sec.getAddress();
     175             :   return Error::success();
     176             : }
     177             : 
     178             : Expected<RuntimeDyldImpl::ObjSectionToIDMap>
     179         346 : RuntimeDyldImpl::loadObjectImpl(const object::ObjectFile &Obj) {
     180             :   MutexGuard locked(lock);
     181             : 
     182             :   // Save information about our target
     183         346 :   Arch = (Triple::ArchType)Obj.getArch();
     184         692 :   IsTargetLittleEndian = Obj.isLittleEndian();
     185         346 :   setMipsABI(Obj);
     186             : 
     187             :   // Compute the memory size required to load all sections to be loaded
     188             :   // and pass this information to the memory manager
     189         346 :   if (MemMgr.needsToReserveAllocationSpace()) {
     190          31 :     uint64_t CodeSize = 0, RODataSize = 0, RWDataSize = 0;
     191          31 :     uint32_t CodeAlign = 1, RODataAlign = 1, RWDataAlign = 1;
     192          31 :     if (auto Err = computeTotalAllocSize(Obj,
     193             :                                          CodeSize, CodeAlign,
     194             :                                          RODataSize, RODataAlign,
     195          31 :                                          RWDataSize, RWDataAlign))
     196             :       return std::move(Err);
     197          62 :     MemMgr.reserveAllocationSpace(CodeSize, CodeAlign, RODataSize, RODataAlign,
     198          31 :                                   RWDataSize, RWDataAlign);
     199             :   }
     200             : 
     201             :   // Used sections from the object file
     202             :   ObjSectionToIDMap LocalSections;
     203             : 
     204             :   // Common symbols requiring allocation, with their sizes and alignments
     205             :   CommonSymbolList CommonSymbolsToAllocate;
     206             : 
     207             :   uint64_t CommonSize = 0;
     208             :   uint32_t CommonAlign = 0;
     209             : 
     210             :   // First, collect all weak and common symbols. We need to know if stronger
     211             :   // definitions occur elsewhere.
     212             :   JITSymbolResolver::LookupFlagsResult SymbolFlags;
     213             :   {
     214             :     JITSymbolResolver::LookupSet Symbols;
     215        3558 :     for (auto &Sym : Obj.symbols()) {
     216             :       uint32_t Flags = Sym.getFlags();
     217        2174 :       if ((Flags & SymbolRef::SF_Common) || (Flags & SymbolRef::SF_Weak)) {
     218             :         // Get symbol name.
     219          56 :         if (auto NameOrErr = Sym.getName())
     220             :           Symbols.insert(*NameOrErr);
     221             :         else
     222             :           return NameOrErr.takeError();
     223             :       }
     224             :     }
     225             : 
     226        1038 :     if (auto FlagsResultOrErr = Resolver.lookupFlags(Symbols))
     227             :       SymbolFlags = std::move(*FlagsResultOrErr);
     228             :     else
     229             :       return FlagsResultOrErr.takeError();
     230             :   }
     231             : 
     232             :   // Parse symbols
     233             :   DEBUG(dbgs() << "Parse symbols:\n");
     234        2866 :   for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
     235             :        ++I) {
     236             :     uint32_t Flags = I->getFlags();
     237             : 
     238             :     // Skip undefined symbols.
     239        2174 :     if (Flags & SymbolRef::SF_Undefined)
     240        1130 :       continue;
     241             : 
     242             :     // Get the symbol type.
     243             :     object::SymbolRef::Type SymType;
     244        1633 :     if (auto SymTypeOrErr = I->getType())
     245        1633 :       SymType = *SymTypeOrErr;
     246             :     else
     247             :       return SymTypeOrErr.takeError();
     248             : 
     249             :     // Get symbol name.
     250        1633 :     StringRef Name;
     251        1633 :     if (auto NameOrErr = I->getName())
     252        1633 :       Name = *NameOrErr;
     253             :     else
     254             :       return NameOrErr.takeError();
     255             : 
     256             :     // Compute JIT symbol flags.
     257        1633 :     JITSymbolFlags JITSymFlags = getJITSymbolFlags(*I);
     258             : 
     259             :     // If this is a weak definition, check to see if there's a strong one.
     260             :     // If there is, skip this symbol (we won't be providing it: the strong
     261             :     // definition will). If there's no strong definition, make this definition
     262             :     // strong.
     263        3255 :     if (JITSymFlags.isWeak() || JITSymFlags.isCommon()) {
     264             :       // First check whether there's already a definition in this instance.
     265             :       // FIXME: Override existing weak definitions with strong ones.
     266          57 :       if (GlobalSymbolTable.count(Name))
     267           1 :         continue;
     268             : 
     269             :       // Then check whether we found flags for an existing symbol during the
     270             :       // flags lookup earlier.
     271             :       auto FlagsI = SymbolFlags.find(Name);
     272           6 :       if (FlagsI == SymbolFlags.end() ||
     273          57 :           (JITSymFlags.isWeak() && !FlagsI->second.isStrong()) ||
     274           0 :           (JITSymFlags.isCommon() && FlagsI->second.isCommon())) {
     275          53 :         if (JITSymFlags.isWeak())
     276           8 :           JITSymFlags &= ~JITSymbolFlags::Weak;
     277          53 :         if (JITSymFlags.isCommon()) {
     278          45 :           JITSymFlags &= ~JITSymbolFlags::Common;
     279             :           uint32_t Align = I->getAlignment();
     280             :           uint64_t Size = I->getCommonSize();
     281          45 :           if (!CommonAlign)
     282             :             CommonAlign = Align;
     283          90 :           CommonSize += alignTo(CommonSize, Align) + Size;
     284          45 :           CommonSymbolsToAllocate.push_back(*I);
     285             :         }
     286             :       } else
     287           2 :         continue;
     288             :     }
     289             : 
     290        1630 :     if (Flags & SymbolRef::SF_Absolute &&
     291             :         SymType != object::SymbolRef::ST_File) {
     292             :       uint64_t Addr = 0;
     293           4 :       if (auto AddrOrErr = I->getAddress())
     294           4 :         Addr = *AddrOrErr;
     295             :       else
     296             :         return AddrOrErr.takeError();
     297             : 
     298             :       unsigned SectionID = AbsoluteSymbolSection;
     299             : 
     300             :       DEBUG(dbgs() << "\tType: " << SymType << " (absolute) Name: " << Name
     301             :                    << " SID: " << SectionID
     302             :                    << " Offset: " << format("%p", (uintptr_t)Addr)
     303             :                    << " flags: " << Flags << "\n");
     304           8 :       GlobalSymbolTable[Name] = SymbolTableEntry(SectionID, Addr, JITSymFlags);
     305        3252 :     } else if (SymType == object::SymbolRef::ST_Function ||
     306        1626 :                SymType == object::SymbolRef::ST_Data ||
     307        1834 :                SymType == object::SymbolRef::ST_Unknown ||
     308         917 :                SymType == object::SymbolRef::ST_Other) {
     309             : 
     310         869 :       section_iterator SI = Obj.section_end();
     311         869 :       if (auto SIOrErr = I->getSection())
     312         869 :         SI = *SIOrErr;
     313             :       else
     314             :         return SIOrErr.takeError();
     315             : 
     316        1783 :       if (SI == Obj.section_end())
     317          45 :         continue;
     318             : 
     319             :       // Get symbol offset.
     320             :       uint64_t SectOffset;
     321        1648 :       if (auto Err = getOffset(*I, *SI, SectOffset))
     322             :         return std::move(Err);
     323             : 
     324             :       bool IsCode = SI->isText();
     325             :       unsigned SectionID;
     326         824 :       if (auto SectionIDOrErr =
     327         824 :               findOrEmitSection(Obj, *SI, IsCode, LocalSections))
     328         824 :         SectionID = *SectionIDOrErr;
     329             :       else
     330             :         return SectionIDOrErr.takeError();
     331             : 
     332             :       DEBUG(dbgs() << "\tType: " << SymType << " Name: " << Name
     333             :                    << " SID: " << SectionID
     334             :                    << " Offset: " << format("%p", (uintptr_t)SectOffset)
     335             :                    << " flags: " << Flags << "\n");
     336        1648 :       GlobalSymbolTable[Name] =
     337         824 :           SymbolTableEntry(SectionID, SectOffset, JITSymFlags);
     338             :     }
     339             :   }
     340             : 
     341             :   // Allocate common symbols
     342         346 :   if (auto Err = emitCommonSymbols(Obj, CommonSymbolsToAllocate, CommonSize,
     343         346 :                                    CommonAlign))
     344             :     return std::move(Err);
     345             : 
     346             :   // Parse and process relocations
     347             :   DEBUG(dbgs() << "Parse relocations:\n");
     348         346 :   for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
     349        3305 :        SI != SE; ++SI) {
     350             :     StubMap Stubs;
     351        2959 :     section_iterator RelocatedSection = SI->getRelocatedSection();
     352             : 
     353        2959 :     if (RelocatedSection == SE)
     354        2325 :       continue;
     355             : 
     356         634 :     relocation_iterator I = SI->relocation_begin();
     357         634 :     relocation_iterator E = SI->relocation_end();
     358             : 
     359         664 :     if (I == E && !ProcessAllSections)
     360          30 :       continue;
     361             : 
     362             :     bool IsCode = RelocatedSection->isText();
     363             :     unsigned SectionID = 0;
     364         604 :     if (auto SectionIDOrErr = findOrEmitSection(Obj, *RelocatedSection, IsCode,
     365         604 :                                                 LocalSections))
     366         604 :       SectionID = *SectionIDOrErr;
     367             :     else
     368             :       return SectionIDOrErr.takeError();
     369             : 
     370             :     DEBUG(dbgs() << "\tSectionID: " << SectionID << "\n");
     371             : 
     372        2021 :     for (; I != E;)
     373        2834 :       if (auto IOrErr = processRelocationRef(SectionID, I, Obj, LocalSections, Stubs))
     374        1417 :         I = *IOrErr;
     375             :       else
     376             :         return IOrErr.takeError();
     377             : 
     378             :     // If there is an attached checker, notify it about the stubs for this
     379             :     // section so that they can be verified.
     380         604 :     if (Checker)
     381          98 :       Checker->registerStubMap(Obj.getFileName(), SectionID, Stubs);
     382             :   }
     383             : 
     384             :   // Give the subclasses a chance to tie-up any loose ends.
     385         692 :   if (auto Err = finalizeLoad(Obj, LocalSections))
     386             :     return std::move(Err);
     387             : 
     388             : //   for (auto E : LocalSections)
     389             : //     llvm::dbgs() << "Added: " << E.first.getRawDataRefImpl() << " -> " << E.second << "\n";
     390             : 
     391             :   return LocalSections;
     392             : }
     393             : 
     394             : // A helper method for computeTotalAllocSize.
     395             : // Computes the memory size required to allocate sections with the given sizes,
     396             : // assuming that all sections are allocated with the given alignment
     397             : static uint64_t
     398             : computeAllocationSizeForSections(std::vector<uint64_t> &SectionSizes,
     399             :                                  uint64_t Alignment) {
     400             :   uint64_t TotalSize = 0;
     401         320 :   for (size_t Idx = 0, Cnt = SectionSizes.size(); Idx < Cnt; Idx++) {
     402             :     uint64_t AlignedSize =
     403          67 :         (SectionSizes[Idx] + Alignment - 1) / Alignment * Alignment;
     404          67 :     TotalSize += AlignedSize;
     405             :   }
     406             :   return TotalSize;
     407             : }
     408             : 
     409        1122 : static bool isRequiredForExecution(const SectionRef Section) {
     410        1122 :   const ObjectFile *Obj = Section.getObject();
     411        1122 :   if (isa<object::ELFObjectFileBase>(Obj))
     412        1068 :     return ELFSectionRef(Section).getFlags() & ELF::SHF_ALLOC;
     413             :   if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj)) {
     414          13 :     const coff_section *CoffSection = COFFObj->getCOFFSection(Section);
     415             :     // Avoid loading zero-sized COFF sections.
     416             :     // In PE files, VirtualSize gives the section size, and SizeOfRawData
     417             :     // may be zero for sections with content. In Obj files, SizeOfRawData
     418             :     // gives the section size, and VirtualSize is always zero. Hence
     419             :     // the need to check for both cases below.
     420             :     bool HasContent =
     421          26 :         (CoffSection->VirtualSize > 0) || (CoffSection->SizeOfRawData > 0);
     422             :     bool IsDiscardable =
     423          13 :         CoffSection->Characteristics &
     424             :         (COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_LNK_INFO);
     425          13 :     return HasContent && !IsDiscardable;
     426             :   }
     427             : 
     428             :   assert(isa<MachOObjectFile>(Obj));
     429             :   return true;
     430             : }
     431             : 
     432         958 : static bool isReadOnlyData(const SectionRef Section) {
     433         958 :   const ObjectFile *Obj = Section.getObject();
     434         958 :   if (isa<object::ELFObjectFileBase>(Obj))
     435        1808 :     return !(ELFSectionRef(Section).getFlags() &
     436         904 :              (ELF::SHF_WRITE | ELF::SHF_EXECINSTR));
     437             :   if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj))
     438          26 :     return ((COFFObj->getCOFFSection(Section)->Characteristics &
     439             :              (COFF::IMAGE_SCN_CNT_INITIALIZED_DATA
     440             :              | COFF::IMAGE_SCN_MEM_READ
     441             :              | COFF::IMAGE_SCN_MEM_WRITE))
     442             :              ==
     443             :              (COFF::IMAGE_SCN_CNT_INITIALIZED_DATA
     444          13 :              | COFF::IMAGE_SCN_MEM_READ));
     445             : 
     446             :   assert(isa<MachOObjectFile>(Obj));
     447             :   return false;
     448             : }
     449             : 
     450         899 : static bool isZeroInit(const SectionRef Section) {
     451         899 :   const ObjectFile *Obj = Section.getObject();
     452         899 :   if (isa<object::ELFObjectFileBase>(Obj))
     453         845 :     return ELFSectionRef(Section).getType() == ELF::SHT_NOBITS;
     454             :   if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj))
     455          26 :     return COFFObj->getCOFFSection(Section)->Characteristics &
     456          13 :             COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA;
     457             : 
     458             :   auto *MachO = cast<MachOObjectFile>(Obj);
     459          41 :   unsigned SectionType = MachO->getSectionType(Section);
     460          41 :   return SectionType == MachO::S_ZEROFILL ||
     461          41 :          SectionType == MachO::S_GB_ZEROFILL;
     462             : }
     463             : 
     464             : // Compute an upper bound of the memory size that is required to load all
     465             : // sections
     466          31 : Error RuntimeDyldImpl::computeTotalAllocSize(const ObjectFile &Obj,
     467             :                                              uint64_t &CodeSize,
     468             :                                              uint32_t &CodeAlign,
     469             :                                              uint64_t &RODataSize,
     470             :                                              uint32_t &RODataAlign,
     471             :                                              uint64_t &RWDataSize,
     472             :                                              uint32_t &RWDataAlign) {
     473             :   // Compute the size of all sections required for execution
     474             :   std::vector<uint64_t> CodeSectionSizes;
     475             :   std::vector<uint64_t> ROSectionSizes;
     476             :   std::vector<uint64_t> RWSectionSizes;
     477             : 
     478             :   // Collect sizes of all sections to be loaded;
     479             :   // also determine the max alignment of all sections
     480          31 :   for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
     481         254 :        SI != SE; ++SI) {
     482             :     const SectionRef &Section = *SI;
     483             : 
     484         223 :     bool IsRequired = isRequiredForExecution(Section) || ProcessAllSections;
     485             : 
     486             :     // Consider only the sections that are required to be loaded for execution
     487             :     if (IsRequired) {
     488             :       uint64_t DataSize = Section.getSize();
     489             :       uint64_t Alignment64 = Section.getAlignment();
     490          59 :       unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
     491             :       bool IsCode = Section.isText();
     492          59 :       bool IsReadOnly = isReadOnlyData(Section);
     493             : 
     494          59 :       StringRef Name;
     495          59 :       if (auto EC = Section.getName(Name))
     496           0 :         return errorCodeToError(EC);
     497             : 
     498          59 :       uint64_t StubBufSize = computeSectionStubBufSize(Obj, Section);
     499          59 :       uint64_t SectionSize = DataSize + StubBufSize;
     500             : 
     501             :       // The .eh_frame section (at least on Linux) needs an extra four bytes
     502             :       // padded
     503             :       // with zeroes added at the end.  For MachO objects, this section has a
     504             :       // slightly different name, so this won't have any effect for MachO
     505             :       // objects.
     506             :       if (Name == ".eh_frame")
     507           5 :         SectionSize += 4;
     508             : 
     509          59 :       if (!SectionSize)
     510           0 :         SectionSize = 1;
     511             : 
     512          59 :       if (IsCode) {
     513          31 :         CodeAlign = std::max(CodeAlign, Alignment);
     514          31 :         CodeSectionSizes.push_back(SectionSize);
     515          28 :       } else if (IsReadOnly) {
     516          17 :         RODataAlign = std::max(RODataAlign, Alignment);
     517          17 :         ROSectionSizes.push_back(SectionSize);
     518             :       } else {
     519          11 :         RWDataAlign = std::max(RWDataAlign, Alignment);
     520          11 :         RWSectionSizes.push_back(SectionSize);
     521             :       }
     522             :     }
     523             :   }
     524             : 
     525             :   // Compute Global Offset Table size. If it is not zero we
     526             :   // also update alignment, which is equal to a size of a
     527             :   // single GOT entry.
     528          31 :   if (unsigned GotSize = computeGOTSize(Obj)) {
     529           8 :     RWSectionSizes.push_back(GotSize);
     530           8 :     RWDataAlign = std::max<uint32_t>(RWDataAlign, getGOTEntrySize());
     531             :   }
     532             : 
     533             :   // Compute the size of all common symbols
     534          31 :   uint64_t CommonSize = 0;
     535          31 :   uint32_t CommonAlign = 1;
     536         236 :   for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
     537             :        ++I) {
     538             :     uint32_t Flags = I->getFlags();
     539         174 :     if (Flags & SymbolRef::SF_Common) {
     540             :       // Add the common symbols to a list.  We'll allocate them all below.
     541             :       uint64_t Size = I->getCommonSize();
     542             :       uint32_t Align = I->getAlignment();
     543             :       // If this is the first common symbol, use its alignment as the alignment
     544             :       // for the common symbols section.
     545           8 :       if (CommonSize == 0)
     546           4 :         CommonAlign = Align;
     547          16 :       CommonSize = alignTo(CommonSize, Align) + Size;
     548             :     }
     549             :   }
     550          31 :   if (CommonSize != 0) {
     551           4 :     RWSectionSizes.push_back(CommonSize);
     552           4 :     RWDataAlign = std::max(RWDataAlign, CommonAlign);
     553             :   }
     554             : 
     555             :   // Compute the required allocation space for each different type of sections
     556             :   // (code, read-only data, read-write data) assuming that all sections are
     557             :   // allocated with the max alignment. Note that we cannot compute with the
     558             :   // individual alignments of the sections, because then the required size
     559             :   // depends on the order, in which the sections are allocated.
     560          62 :   CodeSize = computeAllocationSizeForSections(CodeSectionSizes, CodeAlign);
     561          62 :   RODataSize = computeAllocationSizeForSections(ROSectionSizes, RODataAlign);
     562          62 :   RWDataSize = computeAllocationSizeForSections(RWSectionSizes, RWDataAlign);
     563             : 
     564             :   return Error::success();
     565             : }
     566             : 
     567             : // compute GOT size
     568          31 : unsigned RuntimeDyldImpl::computeGOTSize(const ObjectFile &Obj) {
     569          31 :   size_t GotEntrySize = getGOTEntrySize();
     570          31 :   if (!GotEntrySize)
     571             :     return 0;
     572             : 
     573             :   size_t GotSize = 0;
     574          31 :   for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
     575         254 :        SI != SE; ++SI) {
     576             : 
     577         990 :     for (const RelocationRef &Reloc : SI->relocations())
     578          98 :       if (relocationNeedsGot(Reloc))
     579           6 :         GotSize += GotEntrySize;
     580             :   }
     581             : 
     582          31 :   return GotSize;
     583             : }
     584             : 
     585             : // compute stub buffer size for the given section
     586         958 : unsigned RuntimeDyldImpl::computeSectionStubBufSize(const ObjectFile &Obj,
     587             :                                                     const SectionRef &Section) {
     588         958 :   unsigned StubSize = getMaxStubSize();
     589         958 :   if (StubSize == 0) {
     590             :     return 0;
     591             :   }
     592             :   // FIXME: this is an inefficient way to handle this. We should computed the
     593             :   // necessary section allocation size in loadObject by walking all the sections
     594             :   // once.
     595             :   unsigned StubBufSize = 0;
     596         949 :   for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
     597       10856 :        SI != SE; ++SI) {
     598        9907 :     section_iterator RelSecI = SI->getRelocatedSection();
     599        9907 :     if (!(RelSecI == Section))
     600        9265 :       continue;
     601             : 
     602        4086 :     for (const RelocationRef &Reloc : SI->relocations())
     603        1518 :       if (relocationNeedsStub(Reloc))
     604         498 :         StubBufSize += StubSize;
     605             :   }
     606             : 
     607             :   // Get section data size and alignment
     608             :   uint64_t DataSize = Section.getSize();
     609             :   uint64_t Alignment64 = Section.getAlignment();
     610             : 
     611             :   // Add stubbuf size alignment
     612         949 :   unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
     613         949 :   unsigned StubAlignment = getStubAlignment();
     614         949 :   unsigned EndAlignment = (DataSize | Alignment) & -(DataSize | Alignment);
     615         949 :   if (StubAlignment > EndAlignment)
     616           4 :     StubBufSize += StubAlignment - EndAlignment;
     617             :   return StubBufSize;
     618             : }
     619             : 
     620         374 : uint64_t RuntimeDyldImpl::readBytesUnaligned(uint8_t *Src,
     621             :                                              unsigned Size) const {
     622             :   uint64_t Result = 0;
     623         374 :   if (IsTargetLittleEndian) {
     624         267 :     Src += Size - 1;
     625        2775 :     while (Size--)
     626        1254 :       Result = (Result << 8) | *Src--;
     627             :   } else
     628        1027 :     while (Size--)
     629         460 :       Result = (Result << 8) | *Src++;
     630             : 
     631         374 :   return Result;
     632             : }
     633             : 
     634         255 : void RuntimeDyldImpl::writeBytesUnaligned(uint64_t Value, uint8_t *Dst,
     635             :                                           unsigned Size) const {
     636         255 :   if (IsTargetLittleEndian) {
     637        1812 :     while (Size--) {
     638         820 :       *Dst++ = Value & 0xFF;
     639         820 :       Value >>= 8;
     640             :     }
     641             :   } else {
     642          83 :     Dst += Size - 1;
     643         795 :     while (Size--) {
     644         356 :       *Dst-- = Value & 0xFF;
     645         356 :       Value >>= 8;
     646             :     }
     647             :   }
     648         255 : }
     649             : 
     650        1678 : JITSymbolFlags RuntimeDyldImpl::getJITSymbolFlags(const BasicSymbolRef &SR) {
     651        1678 :   return JITSymbolFlags::fromObjectSymbol(SR);
     652             : }
     653             : 
     654         346 : Error RuntimeDyldImpl::emitCommonSymbols(const ObjectFile &Obj,
     655             :                                          CommonSymbolList &SymbolsToAllocate,
     656             :                                          uint64_t CommonSize,
     657             :                                          uint32_t CommonAlign) {
     658         346 :   if (SymbolsToAllocate.empty())
     659             :     return Error::success();
     660             : 
     661             :   // Allocate memory for the section
     662          25 :   unsigned SectionID = Sections.size();
     663          50 :   uint8_t *Addr = MemMgr.allocateDataSection(CommonSize, CommonAlign, SectionID,
     664          50 :                                              "<common symbols>", false);
     665          25 :   if (!Addr)
     666           0 :     report_fatal_error("Unable to allocate memory for common symbols!");
     667             :   uint64_t Offset = 0;
     668          50 :   Sections.push_back(
     669          25 :       SectionEntry("<common symbols>", Addr, CommonSize, CommonSize, 0));
     670          25 :   memset(Addr, 0, CommonSize);
     671             : 
     672             :   DEBUG(dbgs() << "emitCommonSection SectionID: " << SectionID << " new addr: "
     673             :                << format("%p", Addr) << " DataSize: " << CommonSize << "\n");
     674             : 
     675             :   // Assign the address of each symbol
     676          70 :   for (auto &Sym : SymbolsToAllocate) {
     677             :     uint32_t Align = Sym.getAlignment();
     678             :     uint64_t Size = Sym.getCommonSize();
     679             :     StringRef Name;
     680          45 :     if (auto NameOrErr = Sym.getName())
     681          45 :       Name = *NameOrErr;
     682             :     else
     683             :       return NameOrErr.takeError();
     684          45 :     if (Align) {
     685             :       // This symbol has an alignment requirement.
     686          45 :       uint64_t AlignOffset = OffsetToAlignment((uint64_t)Addr, Align);
     687          45 :       Addr += AlignOffset;
     688          45 :       Offset += AlignOffset;
     689             :     }
     690          45 :     JITSymbolFlags JITSymFlags = getJITSymbolFlags(Sym);
     691             :     DEBUG(dbgs() << "Allocating common symbol " << Name << " address "
     692             :                  << format("%p", Addr) << "\n");
     693          90 :     GlobalSymbolTable[Name] =
     694             :       SymbolTableEntry(SectionID, Offset, JITSymFlags);
     695          45 :     Offset += Size;
     696          45 :     Addr += Size;
     697             :   }
     698             : 
     699          25 :   if (Checker)
     700          10 :     Checker->registerSection(Obj.getFileName(), SectionID);
     701             : 
     702             :   return Error::success();
     703             : }
     704             : 
     705             : Expected<unsigned>
     706         899 : RuntimeDyldImpl::emitSection(const ObjectFile &Obj,
     707             :                              const SectionRef &Section,
     708             :                              bool IsCode) {
     709         899 :   StringRef data;
     710             :   uint64_t Alignment64 = Section.getAlignment();
     711             : 
     712         899 :   unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
     713             :   unsigned PaddingSize = 0;
     714             :   unsigned StubBufSize = 0;
     715         899 :   bool IsRequired = isRequiredForExecution(Section);
     716             :   bool IsVirtual = Section.isVirtual();
     717         899 :   bool IsZeroInit = isZeroInit(Section);
     718         899 :   bool IsReadOnly = isReadOnlyData(Section);
     719             :   uint64_t DataSize = Section.getSize();
     720             : 
     721         899 :   StringRef Name;
     722         899 :   if (auto EC = Section.getName(Name))
     723           0 :     return errorCodeToError(EC);
     724             : 
     725         899 :   StubBufSize = computeSectionStubBufSize(Obj, Section);
     726             : 
     727             :   // The .eh_frame section (at least on Linux) needs an extra four bytes padded
     728             :   // with zeroes added at the end.  For MachO objects, this section has a
     729             :   // slightly different name, so this won't have any effect for MachO objects.
     730             :   if (Name == ".eh_frame")
     731             :     PaddingSize = 4;
     732             : 
     733             :   uintptr_t Allocate;
     734         899 :   unsigned SectionID = Sections.size();
     735             :   uint8_t *Addr;
     736             :   const char *pData = nullptr;
     737             : 
     738             :   // If this section contains any bits (i.e. isn't a virtual or bss section),
     739             :   // grab a reference to them.
     740         899 :   if (!IsVirtual && !IsZeroInit) {
     741             :     // In either case, set the location of the unrelocated section in memory,
     742             :     // since we still process relocations for it even if we're not applying them.
     743         859 :     if (auto EC = Section.getContents(data))
     744           0 :       return errorCodeToError(EC);
     745             :     pData = data.data();
     746             :   }
     747             : 
     748             :   // Code section alignment needs to be at least as high as stub alignment or
     749             :   // padding calculations may by incorrect when the section is remapped to a
     750             :   // higher alignment.
     751         899 :   if (IsCode) {
     752         694 :     Alignment = std::max(Alignment, getStubAlignment());
     753         347 :     if (StubBufSize > 0)
     754          35 :       PaddingSize += getStubAlignment() - 1;
     755             :   }
     756             : 
     757             :   // Some sections, such as debug info, don't need to be loaded for execution.
     758             :   // Process those only if explicitly requested.
     759         899 :   if (IsRequired || ProcessAllSections) {
     760         882 :     Allocate = DataSize + PaddingSize + StubBufSize;
     761         882 :     if (!Allocate)
     762             :       Allocate = 1;
     763        1764 :     Addr = IsCode ? MemMgr.allocateCodeSection(Allocate, Alignment, SectionID,
     764         347 :                                                Name)
     765        1070 :                   : MemMgr.allocateDataSection(Allocate, Alignment, SectionID,
     766         535 :                                                Name, IsReadOnly);
     767         882 :     if (!Addr)
     768           0 :       report_fatal_error("Unable to allocate section memory!");
     769             : 
     770             :     // Zero-initialize or copy the data from the image
     771         882 :     if (IsZeroInit || IsVirtual)
     772          40 :       memset(Addr, 0, DataSize);
     773             :     else
     774         842 :       memcpy(Addr, pData, DataSize);
     775             : 
     776             :     // Fill in any extra bytes we allocated for padding
     777         882 :     if (PaddingSize != 0) {
     778         241 :       memset(Addr + DataSize, 0, PaddingSize);
     779             :       // Update the DataSize variable to include padding.
     780             :       DataSize += PaddingSize;
     781             : 
     782             :       // Align DataSize to stub alignment if we have any stubs (PaddingSize will
     783             :       // have been increased above to account for this).
     784         241 :       if (StubBufSize > 0)
     785          15 :         DataSize &= ~(getStubAlignment() - 1);
     786             :     }
     787             : 
     788             :     DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
     789             :                  << " obj addr: " << format("%p", pData)
     790             :                  << " new addr: " << format("%p", Addr)
     791             :                  << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
     792             :                  << " Allocate: " << Allocate << "\n");
     793             :   } else {
     794             :     // Even if we didn't load the section, we need to record an entry for it
     795             :     // to handle later processing (and by 'handle' I mean don't do anything
     796             :     // with these sections).
     797             :     Allocate = 0;
     798             :     Addr = nullptr;
     799             :     DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
     800             :                  << " obj addr: " << format("%p", data.data()) << " new addr: 0"
     801             :                  << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
     802             :                  << " Allocate: " << Allocate << "\n");
     803             :   }
     804             : 
     805        1798 :   Sections.push_back(
     806        1798 :       SectionEntry(Name, Addr, DataSize, Allocate, (uintptr_t)pData));
     807             : 
     808             :   // Debug info sections are linked as if their load address was zero
     809         899 :   if (!IsRequired)
     810          98 :     Sections.back().setLoadAddress(0);
     811             : 
     812         899 :   if (Checker)
     813         127 :     Checker->registerSection(Obj.getFileName(), SectionID);
     814             : 
     815             :   return SectionID;
     816             : }
     817             : 
     818             : Expected<unsigned>
     819        2321 : RuntimeDyldImpl::findOrEmitSection(const ObjectFile &Obj,
     820             :                                    const SectionRef &Section,
     821             :                                    bool IsCode,
     822             :                                    ObjSectionToIDMap &LocalSections) {
     823             : 
     824             :   unsigned SectionID = 0;
     825             :   ObjSectionToIDMap::iterator i = LocalSections.find(Section);
     826        2321 :   if (i != LocalSections.end())
     827        1422 :     SectionID = i->second;
     828             :   else {
     829        1798 :     if (auto SectionIDOrErr = emitSection(Obj, Section, IsCode))
     830         899 :       SectionID = *SectionIDOrErr;
     831             :     else
     832             :       return SectionIDOrErr.takeError();
     833         899 :     LocalSections[Section] = SectionID;
     834             :   }
     835             :   return SectionID;
     836             : }
     837             : 
     838        1200 : void RuntimeDyldImpl::addRelocationForSection(const RelocationEntry &RE,
     839             :                                               unsigned SectionID) {
     840        1200 :   Relocations[SectionID].push_back(RE);
     841        1200 : }
     842             : 
     843         276 : void RuntimeDyldImpl::addRelocationForSymbol(const RelocationEntry &RE,
     844             :                                              StringRef SymbolName) {
     845             :   // Relocation by symbol.  If the symbol is found in the global symbol table,
     846             :   // create an appropriate section relocation.  Otherwise, add it to
     847             :   // ExternalSymbolRelocations.
     848         552 :   RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(SymbolName);
     849         552 :   if (Loc == GlobalSymbolTable.end()) {
     850         546 :     ExternalSymbolRelocations[SymbolName].push_back(RE);
     851             :   } else {
     852             :     // Copy the RE since we want to modify its addend.
     853           3 :     RelocationEntry RECopy = RE;
     854             :     const auto &SymInfo = Loc->second;
     855           3 :     RECopy.Addend += SymInfo.getOffset();
     856           6 :     Relocations[SymInfo.getSectionID()].push_back(RECopy);
     857             :   }
     858         276 : }
     859             : 
     860          18 : uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr,
     861             :                                              unsigned AbiVariant) {
     862          18 :   if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be) {
     863             :     // This stub has to be able to access the full address space,
     864             :     // since symbol lookup won't necessarily find a handy, in-range,
     865             :     // PLT stub for functions which could be anywhere.
     866             :     // Stub can use ip0 (== x16) to calculate address
     867           0 :     writeBytesUnaligned(0xd2e00010, Addr,    4); // movz ip0, #:abs_g3:<addr>
     868           0 :     writeBytesUnaligned(0xf2c00010, Addr+4,  4); // movk ip0, #:abs_g2_nc:<addr>
     869           0 :     writeBytesUnaligned(0xf2a00010, Addr+8,  4); // movk ip0, #:abs_g1_nc:<addr>
     870           0 :     writeBytesUnaligned(0xf2800010, Addr+12, 4); // movk ip0, #:abs_g0_nc:<addr>
     871           0 :     writeBytesUnaligned(0xd61f0200, Addr+16, 4); // br ip0
     872             : 
     873           0 :     return Addr;
     874          18 :   } else if (Arch == Triple::arm || Arch == Triple::armeb) {
     875             :     // TODO: There is only ARM far stub now. We should add the Thumb stub,
     876             :     // and stubs for branches Thumb - ARM and ARM - Thumb.
     877           0 :     writeBytesUnaligned(0xe51ff004, Addr, 4); // ldr pc, [pc, #-4]
     878           0 :     return Addr + 4;
     879          18 :   } else if (IsMipsO32ABI || IsMipsN32ABI) {
     880             :     // 0:   3c190000        lui     t9,%hi(addr).
     881             :     // 4:   27390000        addiu   t9,t9,%lo(addr).
     882             :     // 8:   03200008        jr      t9.
     883             :     // c:   00000000        nop.
     884             :     const unsigned LuiT9Instr = 0x3c190000, AdduiT9Instr = 0x27390000;
     885             :     const unsigned NopInstr = 0x0;
     886             :     unsigned JrT9Instr = 0x03200008;
     887           4 :     if ((AbiVariant & ELF::EF_MIPS_ARCH) == ELF::EF_MIPS_ARCH_32R6 ||
     888             :         (AbiVariant & ELF::EF_MIPS_ARCH) == ELF::EF_MIPS_ARCH_64R6)
     889             :       JrT9Instr = 0x03200009;
     890             : 
     891           4 :     writeBytesUnaligned(LuiT9Instr, Addr, 4);
     892           4 :     writeBytesUnaligned(AdduiT9Instr, Addr + 4, 4);
     893           4 :     writeBytesUnaligned(JrT9Instr, Addr + 8, 4);
     894           4 :     writeBytesUnaligned(NopInstr, Addr + 12, 4);
     895           4 :     return Addr;
     896          14 :   } else if (IsMipsN64ABI) {
     897             :     // 0:   3c190000        lui     t9,%highest(addr).
     898             :     // 4:   67390000        daddiu  t9,t9,%higher(addr).
     899             :     // 8:   0019CC38        dsll    t9,t9,16.
     900             :     // c:   67390000        daddiu  t9,t9,%hi(addr).
     901             :     // 10:  0019CC38        dsll    t9,t9,16.
     902             :     // 14:  67390000        daddiu  t9,t9,%lo(addr).
     903             :     // 18:  03200008        jr      t9.
     904             :     // 1c:  00000000        nop.
     905             :     const unsigned LuiT9Instr = 0x3c190000, DaddiuT9Instr = 0x67390000,
     906             :                    DsllT9Instr = 0x19CC38;
     907             :     const unsigned NopInstr = 0x0;
     908             :     unsigned JrT9Instr = 0x03200008;
     909           2 :     if ((AbiVariant & ELF::EF_MIPS_ARCH) == ELF::EF_MIPS_ARCH_64R6)
     910             :       JrT9Instr = 0x03200009;
     911             : 
     912           2 :     writeBytesUnaligned(LuiT9Instr, Addr, 4);
     913           2 :     writeBytesUnaligned(DaddiuT9Instr, Addr + 4, 4);
     914           2 :     writeBytesUnaligned(DsllT9Instr, Addr + 8, 4);
     915           2 :     writeBytesUnaligned(DaddiuT9Instr, Addr + 12, 4);
     916           2 :     writeBytesUnaligned(DsllT9Instr, Addr + 16, 4);
     917           2 :     writeBytesUnaligned(DaddiuT9Instr, Addr + 20, 4);
     918           2 :     writeBytesUnaligned(JrT9Instr, Addr + 24, 4);
     919           2 :     writeBytesUnaligned(NopInstr, Addr + 28, 4);
     920           2 :     return Addr;
     921          12 :   } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
     922             :     // Depending on which version of the ELF ABI is in use, we need to
     923             :     // generate one of two variants of the stub.  They both start with
     924             :     // the same sequence to load the target address into r12.
     925           0 :     writeInt32BE(Addr,    0x3D800000); // lis   r12, highest(addr)
     926           0 :     writeInt32BE(Addr+4,  0x618C0000); // ori   r12, higher(addr)
     927           0 :     writeInt32BE(Addr+8,  0x798C07C6); // sldi  r12, r12, 32
     928           0 :     writeInt32BE(Addr+12, 0x658C0000); // oris  r12, r12, h(addr)
     929           0 :     writeInt32BE(Addr+16, 0x618C0000); // ori   r12, r12, l(addr)
     930           0 :     if (AbiVariant == 2) {
     931             :       // PowerPC64 stub ELFv2 ABI: The address points to the function itself.
     932             :       // The address is already in r12 as required by the ABI.  Branch to it.
     933           0 :       writeInt32BE(Addr+20, 0xF8410018); // std   r2,  24(r1)
     934           0 :       writeInt32BE(Addr+24, 0x7D8903A6); // mtctr r12
     935           0 :       writeInt32BE(Addr+28, 0x4E800420); // bctr
     936             :     } else {
     937             :       // PowerPC64 stub ELFv1 ABI: The address points to a function descriptor.
     938             :       // Load the function address on r11 and sets it to control register. Also
     939             :       // loads the function TOC in r2 and environment pointer to r11.
     940           0 :       writeInt32BE(Addr+20, 0xF8410028); // std   r2,  40(r1)
     941           0 :       writeInt32BE(Addr+24, 0xE96C0000); // ld    r11, 0(r12)
     942           0 :       writeInt32BE(Addr+28, 0xE84C0008); // ld    r2,  0(r12)
     943           0 :       writeInt32BE(Addr+32, 0x7D6903A6); // mtctr r11
     944           0 :       writeInt32BE(Addr+36, 0xE96C0010); // ld    r11, 16(r2)
     945           0 :       writeInt32BE(Addr+40, 0x4E800420); // bctr
     946             :     }
     947             :     return Addr;
     948          12 :   } else if (Arch == Triple::systemz) {
     949             :     writeInt16BE(Addr,    0xC418);     // lgrl %r1,.+8
     950             :     writeInt16BE(Addr+2,  0x0000);
     951             :     writeInt16BE(Addr+4,  0x0004);
     952             :     writeInt16BE(Addr+6,  0x07F1);     // brc 15,%r1
     953             :     // 8-byte address stored at Addr + 8
     954           0 :     return Addr;
     955          12 :   } else if (Arch == Triple::x86_64) {
     956          11 :     *Addr      = 0xFF; // jmp
     957          11 :     *(Addr+1)  = 0x25; // rip
     958             :     // 32-bit PC-relative address of the GOT entry will be stored at Addr+2
     959           1 :   } else if (Arch == Triple::x86) {
     960           1 :     *Addr      = 0xE9; // 32-bit pc-relative jump.
     961             :   }
     962             :   return Addr;
     963             : }
     964             : 
     965             : // Assign an address to a symbol name and resolve all the relocations
     966             : // associated with it.
     967         194 : void RuntimeDyldImpl::reassignSectionAddress(unsigned SectionID,
     968             :                                              uint64_t Addr) {
     969             :   // The address to use for relocation resolution is not
     970             :   // the address of the local section buffer. We must be doing
     971             :   // a remote execution environment of some sort. Relocations can't
     972             :   // be applied until all the sections have been moved.  The client must
     973             :   // trigger this with a call to MCJIT::finalize() or
     974             :   // RuntimeDyld::resolveRelocations().
     975             :   //
     976             :   // Addr is a uint64_t because we can't assume the pointer width
     977             :   // of the target is the same as that of the host. Just use a generic
     978             :   // "big enough" type.
     979             :   DEBUG(dbgs() << "Reassigning address for section " << SectionID << " ("
     980             :                << Sections[SectionID].getName() << "): "
     981             :                << format("0x%016" PRIx64, Sections[SectionID].getLoadAddress())
     982             :                << " -> " << format("0x%016" PRIx64, Addr) << "\n");
     983         194 :   Sections[SectionID].setLoadAddress(Addr);
     984         194 : }
     985             : 
     986         713 : void RuntimeDyldImpl::resolveRelocationList(const RelocationList &Relocs,
     987             :                                             uint64_t Value) {
     988        2185 :   for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
     989        1472 :     const RelocationEntry &RE = Relocs[i];
     990             :     // Ignore relocations for sections that were not loaded
     991        2944 :     if (Sections[RE.SectionID].getAddress() == nullptr)
     992         190 :       continue;
     993        1282 :     resolveRelocation(RE, Value);
     994             :   }
     995         713 : }
     996             : 
     997         476 : Error RuntimeDyldImpl::resolveExternalSymbols() {
     998         476 :   StringMap<JITEvaluatedSymbol> ExternalSymbolMap;
     999             : 
    1000             :   // Resolution can trigger emission of more symbols, so iterate until
    1001             :   // we've resolved *everything*.
    1002             :   {
    1003             :     JITSymbolResolver::LookupSet ResolvedSymbols;
    1004             : 
    1005             :     while (true) {
    1006             :       JITSymbolResolver::LookupSet NewSymbols;
    1007             : 
    1008        1484 :       for (auto &RelocKV : ExternalSymbolRelocations) {
    1009         354 :         StringRef Name = RelocKV.first();
    1010         354 :         if (!Name.empty() && !GlobalSymbolTable.count(Name) &&
    1011             :             !ResolvedSymbols.count(Name))
    1012             :           NewSymbols.insert(Name);
    1013             :       }
    1014             : 
    1015         565 :       if (NewSymbols.empty())
    1016             :         break;
    1017             : 
    1018         178 :       auto NewResolverResults = Resolver.lookup(NewSymbols);
    1019          89 :       if (!NewResolverResults)
    1020           0 :         return NewResolverResults.takeError();
    1021             : 
    1022         252 :       for (auto &RRKV : *NewResolverResults) {
    1023             :         assert(!ResolvedSymbols.count(RRKV.first) && "Redundant resolution?");
    1024             :         ExternalSymbolMap.insert(RRKV);
    1025         163 :         ResolvedSymbols.insert(RRKV.first);
    1026             :       }
    1027             :     }
    1028             :   }
    1029             : 
    1030         850 :   while (!ExternalSymbolRelocations.empty()) {
    1031             : 
    1032         187 :     StringMap<RelocationList>::iterator i = ExternalSymbolRelocations.begin();
    1033             : 
    1034         187 :     StringRef Name = i->first();
    1035         187 :     if (Name.size() == 0) {
    1036             :       // This is an absolute symbol, use an address of zero.
    1037             :       DEBUG(dbgs() << "Resolving absolute relocations."
    1038             :                    << "\n");
    1039           0 :       RelocationList &Relocs = i->second;
    1040           0 :       resolveRelocationList(Relocs, 0);
    1041             :     } else {
    1042             :       uint64_t Addr = 0;
    1043         187 :       JITSymbolFlags Flags;
    1044         374 :       RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(Name);
    1045         374 :       if (Loc == GlobalSymbolTable.end()) {
    1046         151 :         auto RRI = ExternalSymbolMap.find(Name);
    1047             :         assert(RRI != ExternalSymbolMap.end() && "No result for symbol");
    1048         151 :         Addr = RRI->second.getAddress();
    1049         151 :         Flags = RRI->second.getFlags();
    1050             :         // The call to getSymbolAddress may have caused additional modules to
    1051             :         // be loaded, which may have added new entries to the
    1052             :         // ExternalSymbolRelocations map.  Consquently, we need to update our
    1053             :         // iterator.  This is also why retrieval of the relocation list
    1054             :         // associated with this symbol is deferred until below this point.
    1055             :         // New entries may have been added to the relocation list.
    1056         151 :         i = ExternalSymbolRelocations.find(Name);
    1057             :       } else {
    1058             :         // We found the symbol in our global table.  It was probably in a
    1059             :         // Module that we loaded previously.
    1060             :         const auto &SymInfo = Loc->second;
    1061          72 :         Addr = getSectionLoadAddress(SymInfo.getSectionID()) +
    1062          36 :                SymInfo.getOffset();
    1063          36 :         Flags = SymInfo.getFlags();
    1064             :       }
    1065             : 
    1066             :       // FIXME: Implement error handling that doesn't kill the host program!
    1067         187 :       if (!Addr)
    1068           0 :         report_fatal_error("Program used external function '" + Name +
    1069             :                            "' which could not be resolved!");
    1070             : 
    1071             :       // If Resolver returned UINT64_MAX, the client wants to handle this symbol
    1072             :       // manually and we shouldn't resolve its relocations.
    1073         187 :       if (Addr != UINT64_MAX) {
    1074             : 
    1075             :         // Tweak the address based on the symbol flags if necessary.
    1076             :         // For example, this is used by RuntimeDyldMachOARM to toggle the low bit
    1077             :         // if the target symbol is Thumb.
    1078         183 :         Addr = modifyAddressBasedOnFlags(Addr, Flags);
    1079             : 
    1080             :         DEBUG(dbgs() << "Resolving relocations Name: " << Name << "\t"
    1081             :                      << format("0x%lx", Addr) << "\n");
    1082             :         // This list may have been updated when we called getSymbolAddress, so
    1083             :         // don't change this code to get the list earlier.
    1084         183 :         RelocationList &Relocs = i->second;
    1085         183 :         resolveRelocationList(Relocs, Addr);
    1086             :       }
    1087             :     }
    1088             : 
    1089             :     ExternalSymbolRelocations.erase(i);
    1090             :   }
    1091             : 
    1092             :   return Error::success();
    1093             : }
    1094             : 
    1095             : //===----------------------------------------------------------------------===//
    1096             : // RuntimeDyld class implementation
    1097             : 
    1098        1372 : uint64_t RuntimeDyld::LoadedObjectInfo::getSectionLoadAddress(
    1099             :                                           const object::SectionRef &Sec) const {
    1100             : 
    1101             :   auto I = ObjSecToIDMap.find(Sec);
    1102        1372 :   if (I != ObjSecToIDMap.end())
    1103        1032 :     return RTDyld.Sections[I->second].getLoadAddress();
    1104             : 
    1105             :   return 0;
    1106             : }
    1107             : 
    1108           0 : void RuntimeDyld::MemoryManager::anchor() {}
    1109           0 : void JITSymbolResolver::anchor() {}
    1110           0 : void LegacyJITSymbolResolver::anchor() {}
    1111             : 
    1112         305 : RuntimeDyld::RuntimeDyld(RuntimeDyld::MemoryManager &MemMgr,
    1113         305 :                          JITSymbolResolver &Resolver)
    1114         305 :     : MemMgr(MemMgr), Resolver(Resolver) {
    1115             :   // FIXME: There's a potential issue lurking here if a single instance of
    1116             :   // RuntimeDyld is used to load multiple objects.  The current implementation
    1117             :   // associates a single memory manager with a RuntimeDyld instance.  Even
    1118             :   // though the public class spawns a new 'impl' instance for each load,
    1119             :   // they share a single memory manager.  This can become a problem when page
    1120             :   // permissions are applied.
    1121             :   Dyld = nullptr;
    1122         305 :   ProcessAllSections = false;
    1123         305 :   Checker = nullptr;
    1124         305 : }
    1125             : 
    1126         466 : RuntimeDyld::~RuntimeDyld() {}
    1127             : 
    1128             : static std::unique_ptr<RuntimeDyldCOFF>
    1129             : createRuntimeDyldCOFF(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM,
    1130             :                       JITSymbolResolver &Resolver, bool ProcessAllSections,
    1131             :                       RuntimeDyldCheckerImpl *Checker) {
    1132             :   std::unique_ptr<RuntimeDyldCOFF> Dyld =
    1133           3 :     RuntimeDyldCOFF::create(Arch, MM, Resolver);
    1134             :   Dyld->setProcessAllSections(ProcessAllSections);
    1135             :   Dyld->setRuntimeDyldChecker(Checker);
    1136             :   return Dyld;
    1137             : }
    1138             : 
    1139             : static std::unique_ptr<RuntimeDyldELF>
    1140             : createRuntimeDyldELF(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM,
    1141             :                      JITSymbolResolver &Resolver, bool ProcessAllSections,
    1142             :                      RuntimeDyldCheckerImpl *Checker) {
    1143             :   std::unique_ptr<RuntimeDyldELF> Dyld =
    1144         284 :       RuntimeDyldELF::create(Arch, MM, Resolver);
    1145             :   Dyld->setProcessAllSections(ProcessAllSections);
    1146             :   Dyld->setRuntimeDyldChecker(Checker);
    1147             :   return Dyld;
    1148             : }
    1149             : 
    1150             : static std::unique_ptr<RuntimeDyldMachO>
    1151             : createRuntimeDyldMachO(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM,
    1152             :                        JITSymbolResolver &Resolver,
    1153             :                        bool ProcessAllSections,
    1154             :                        RuntimeDyldCheckerImpl *Checker) {
    1155             :   std::unique_ptr<RuntimeDyldMachO> Dyld =
    1156          11 :     RuntimeDyldMachO::create(Arch, MM, Resolver);
    1157             :   Dyld->setProcessAllSections(ProcessAllSections);
    1158             :   Dyld->setRuntimeDyldChecker(Checker);
    1159             :   return Dyld;
    1160             : }
    1161             : 
    1162             : std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
    1163         346 : RuntimeDyld::loadObject(const ObjectFile &Obj) {
    1164         346 :   if (!Dyld) {
    1165         596 :     if (Obj.isELF())
    1166             :       Dyld =
    1167         852 :           createRuntimeDyldELF(static_cast<Triple::ArchType>(Obj.getArch()),
    1168         284 :                                MemMgr, Resolver, ProcessAllSections, Checker);
    1169          14 :     else if (Obj.isMachO())
    1170          44 :       Dyld = createRuntimeDyldMachO(
    1171          11 :                static_cast<Triple::ArchType>(Obj.getArch()), MemMgr, Resolver,
    1172          11 :                ProcessAllSections, Checker);
    1173           3 :     else if (Obj.isCOFF())
    1174          12 :       Dyld = createRuntimeDyldCOFF(
    1175           3 :                static_cast<Triple::ArchType>(Obj.getArch()), MemMgr, Resolver,
    1176           3 :                ProcessAllSections, Checker);
    1177             :     else
    1178           0 :       report_fatal_error("Incompatible object format!");
    1179             :   }
    1180             : 
    1181         346 :   if (!Dyld->isCompatibleFile(Obj))
    1182           0 :     report_fatal_error("Incompatible object format!");
    1183             : 
    1184         346 :   auto LoadedObjInfo = Dyld->loadObject(Obj);
    1185         346 :   MemMgr.notifyObjectLoaded(*this, Obj);
    1186         346 :   return LoadedObjInfo;
    1187             : }
    1188             : 
    1189           0 : void *RuntimeDyld::getSymbolLocalAddress(StringRef Name) const {
    1190           0 :   if (!Dyld)
    1191             :     return nullptr;
    1192           0 :   return Dyld->getSymbolLocalAddress(Name);
    1193             : }
    1194             : 
    1195         854 : JITEvaluatedSymbol RuntimeDyld::getSymbol(StringRef Name) const {
    1196         854 :   if (!Dyld)
    1197             :     return nullptr;
    1198         820 :   return Dyld->getSymbol(Name);
    1199             : }
    1200             : 
    1201         952 : void RuntimeDyld::resolveRelocations() { Dyld->resolveRelocations(); }
    1202             : 
    1203           0 : void RuntimeDyld::reassignSectionAddress(unsigned SectionID, uint64_t Addr) {
    1204           0 :   Dyld->reassignSectionAddress(SectionID, Addr);
    1205           0 : }
    1206             : 
    1207         194 : void RuntimeDyld::mapSectionAddress(const void *LocalAddress,
    1208             :                                     uint64_t TargetAddress) {
    1209         194 :   Dyld->mapSectionAddress(LocalAddress, TargetAddress);
    1210         194 : }
    1211             : 
    1212         764 : bool RuntimeDyld::hasError() { return Dyld->hasError(); }
    1213             : 
    1214           0 : StringRef RuntimeDyld::getErrorString() { return Dyld->getErrorString(); }
    1215             : 
    1216         120 : void RuntimeDyld::finalizeWithMemoryManagerLocking() {
    1217         120 :   bool MemoryFinalizationLocked = MemMgr.FinalizationLocked;
    1218         120 :   MemMgr.FinalizationLocked = true;
    1219         120 :   resolveRelocations();
    1220         120 :   registerEHFrames();
    1221         120 :   if (!MemoryFinalizationLocked) {
    1222         102 :     MemMgr.finalizeMemory();
    1223         102 :     MemMgr.FinalizationLocked = false;
    1224             :   }
    1225         120 : }
    1226             : 
    1227         469 : void RuntimeDyld::registerEHFrames() {
    1228         469 :   if (Dyld)
    1229         469 :     Dyld->registerEHFrames();
    1230         469 : }
    1231             : 
    1232          67 : void RuntimeDyld::deregisterEHFrames() {
    1233          67 :   if (Dyld)
    1234          64 :     Dyld->deregisterEHFrames();
    1235          67 : }
    1236             : 
    1237             : } // end namespace llvm

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