LCOV - code coverage report
Current view: top level - lib/ExecutionEngine/RuntimeDyld - RuntimeDyld.cpp (source / functions) Hit Total Coverage
Test: llvm-toolchain.info Lines: 422 476 88.7 %
Date: 2018-09-23 13:06:45 Functions: 36 49 73.5 %
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         693 : 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          46 : void RuntimeDyldImpl::deregisterEHFrames() {
      77          46 :   MemMgr.deregisterEHFrames();
      78          46 : }
      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         480 : void RuntimeDyldImpl::resolveRelocations() {
     122             :   MutexGuard locked(lock);
     123             : 
     124             :   // Print out the sections prior to relocation.
     125             :   LLVM_DEBUG(for (int i = 0, e = Sections.size(); i != e; ++i)
     126             :                  dumpSectionMemory(Sections[i], "before relocations"););
     127             : 
     128             :   // First, resolve relocations associated with external symbols.
     129         960 :   if (auto Err = resolveExternalSymbols()) {
     130           0 :     HasError = true;
     131           0 :     ErrorStr = toString(std::move(Err));
     132             :   }
     133             : 
     134             :   // Iterate over all outstanding relocations
     135         973 :   for (auto it = Relocations.begin(), e = Relocations.end(); it != e; ++it) {
     136             :     // The Section here (Sections[i]) refers to the section in which the
     137             :     // symbol for the relocation is located.  The SectionID in the relocation
     138             :     // entry provides the section to which the relocation will be applied.
     139         493 :     int Idx = it->first;
     140         493 :     uint64_t Addr = Sections[Idx].getLoadAddress();
     141             :     LLVM_DEBUG(dbgs() << "Resolving relocations Section #" << Idx << "\t"
     142             :                       << format("%p", (uintptr_t)Addr) << "\n");
     143         493 :     resolveRelocationList(it->second, Addr);
     144             :   }
     145             :   Relocations.clear();
     146             : 
     147             :   // Print out sections after relocation.
     148             :   LLVM_DEBUG(for (int i = 0, e = Sections.size(); i != e; ++i)
     149             :                  dumpSectionMemory(Sections[i], "after relocations"););
     150         480 : }
     151             : 
     152         218 : void RuntimeDyldImpl::mapSectionAddress(const void *LocalAddress,
     153             :                                         uint64_t TargetAddress) {
     154             :   MutexGuard locked(lock);
     155         577 :   for (unsigned i = 0, e = Sections.size(); i != e; ++i) {
     156         577 :     if (Sections[i].getAddress() == LocalAddress) {
     157         218 :       reassignSectionAddress(i, TargetAddress);
     158         218 :       return;
     159             :     }
     160             :   }
     161           0 :   llvm_unreachable("Attempting to remap address of unknown section!");
     162             : }
     163             : 
     164         817 : static Error getOffset(const SymbolRef &Sym, SectionRef Sec,
     165             :                        uint64_t &Result) {
     166             :   Expected<uint64_t> AddressOrErr = Sym.getAddress();
     167         817 :   if (!AddressOrErr)
     168             :     return AddressOrErr.takeError();
     169         817 :   Result = *AddressOrErr - Sec.getAddress();
     170             :   return Error::success();
     171             : }
     172             : 
     173             : Expected<RuntimeDyldImpl::ObjSectionToIDMap>
     174         353 : RuntimeDyldImpl::loadObjectImpl(const object::ObjectFile &Obj) {
     175             :   MutexGuard locked(lock);
     176             : 
     177             :   // Save information about our target
     178         353 :   Arch = (Triple::ArchType)Obj.getArch();
     179         353 :   IsTargetLittleEndian = Obj.isLittleEndian();
     180         353 :   setMipsABI(Obj);
     181             : 
     182             :   // Compute the memory size required to load all sections to be loaded
     183             :   // and pass this information to the memory manager
     184         353 :   if (MemMgr.needsToReserveAllocationSpace()) {
     185          31 :     uint64_t CodeSize = 0, RODataSize = 0, RWDataSize = 0;
     186          31 :     uint32_t CodeAlign = 1, RODataAlign = 1, RWDataAlign = 1;
     187          31 :     if (auto Err = computeTotalAllocSize(Obj,
     188             :                                          CodeSize, CodeAlign,
     189             :                                          RODataSize, RODataAlign,
     190          31 :                                          RWDataSize, RWDataAlign))
     191             :       return std::move(Err);
     192          62 :     MemMgr.reserveAllocationSpace(CodeSize, CodeAlign, RODataSize, RODataAlign,
     193          31 :                                   RWDataSize, RWDataAlign);
     194             :   }
     195             : 
     196             :   // Used sections from the object file
     197             :   ObjSectionToIDMap LocalSections;
     198             : 
     199             :   // Common symbols requiring allocation, with their sizes and alignments
     200             :   CommonSymbolList CommonSymbolsToAllocate;
     201             : 
     202             :   uint64_t CommonSize = 0;
     203             :   uint32_t CommonAlign = 0;
     204             : 
     205             :   // First, collect all weak and common symbols. We need to know if stronger
     206             :   // definitions occur elsewhere.
     207             :   JITSymbolResolver::LookupSet ResponsibilitySet;
     208             :   {
     209             :     JITSymbolResolver::LookupSet Symbols;
     210        2547 :     for (auto &Sym : Obj.symbols()) {
     211        2194 :       uint32_t Flags = Sym.getFlags();
     212        2194 :       if ((Flags & SymbolRef::SF_Common) || (Flags & SymbolRef::SF_Weak)) {
     213             :         // Get symbol name.
     214          98 :         if (auto NameOrErr = Sym.getName())
     215             :           Symbols.insert(*NameOrErr);
     216             :         else
     217             :           return NameOrErr.takeError();
     218             :       }
     219             :     }
     220             : 
     221         706 :     if (auto ResultOrErr = Resolver.getResponsibilitySet(Symbols))
     222             :       ResponsibilitySet = std::move(*ResultOrErr);
     223             :     else
     224             :       return ResultOrErr.takeError();
     225             :   }
     226             : 
     227             :   // Parse symbols
     228             :   LLVM_DEBUG(dbgs() << "Parse symbols:\n");
     229        2547 :   for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
     230             :        ++I) {
     231        2194 :     uint32_t Flags = I->getFlags();
     232             : 
     233             :     // Skip undefined symbols.
     234        2194 :     if (Flags & SymbolRef::SF_Undefined)
     235         654 :       continue;
     236             : 
     237             :     // Get the symbol type.
     238             :     object::SymbolRef::Type SymType;
     239        1629 :     if (auto SymTypeOrErr = I->getType())
     240        1629 :       SymType = *SymTypeOrErr;
     241             :     else
     242             :       return SymTypeOrErr.takeError();
     243             : 
     244             :     // Get symbol name.
     245        1629 :     StringRef Name;
     246        1629 :     if (auto NameOrErr = I->getName())
     247        1629 :       Name = *NameOrErr;
     248             :     else
     249             :       return NameOrErr.takeError();
     250             : 
     251             :     // Compute JIT symbol flags.
     252        1629 :     auto JITSymFlags = getJITSymbolFlags(*I);
     253        1629 :     if (!JITSymFlags)
     254             :       return JITSymFlags.takeError();
     255             : 
     256             :     // If this is a weak definition, check to see if there's a strong one.
     257             :     // If there is, skip this symbol (we won't be providing it: the strong
     258             :     // definition will). If there's no strong definition, make this definition
     259             :     // strong.
     260        3258 :     if (JITSymFlags->isWeak() || JITSymFlags->isCommon()) {
     261             :       // First check whether there's already a definition in this instance.
     262         195 :       if (GlobalSymbolTable.count(Name))
     263           1 :         continue;
     264             : 
     265             :       // If we're not responsible for this symbol, skip it.
     266             :       if (!ResponsibilitySet.count(Name))
     267           3 :         continue;
     268             : 
     269             :       // Otherwise update the flags on the symbol to make this definition
     270             :       // strong.
     271         188 :       if (JITSymFlags->isWeak())
     272             :         *JITSymFlags &= ~JITSymbolFlags::Weak;
     273         188 :       if (JITSymFlags->isCommon()) {
     274             :         *JITSymFlags &= ~JITSymbolFlags::Common;
     275             :         uint32_t Align = I->getAlignment();
     276             :         uint64_t Size = I->getCommonSize();
     277          85 :         if (!CommonAlign)
     278             :           CommonAlign = Align;
     279          85 :         CommonSize = alignTo(CommonSize, Align) + Size;
     280          85 :         CommonSymbolsToAllocate.push_back(*I);
     281             :       }
     282             :     }
     283             : 
     284        1625 :     if (Flags & SymbolRef::SF_Absolute &&
     285             :         SymType != object::SymbolRef::ST_File) {
     286             :       uint64_t Addr = 0;
     287           1 :       if (auto AddrOrErr = I->getAddress())
     288           1 :         Addr = *AddrOrErr;
     289             :       else
     290             :         return AddrOrErr.takeError();
     291             : 
     292             :       unsigned SectionID = AbsoluteSymbolSection;
     293             : 
     294             :       LLVM_DEBUG(dbgs() << "\tType: " << SymType << " (absolute) Name: " << Name
     295             :                         << " SID: " << SectionID
     296             :                         << " Offset: " << format("%p", (uintptr_t)Addr)
     297             :                         << " flags: " << Flags << "\n");
     298           1 :       GlobalSymbolTable[Name] = SymbolTableEntry(SectionID, Addr, *JITSymFlags);
     299        3248 :     } else if (SymType == object::SymbolRef::ST_Function ||
     300        1624 :                SymType == object::SymbolRef::ST_Data ||
     301        1758 :                SymType == object::SymbolRef::ST_Unknown ||
     302         879 :                SymType == object::SymbolRef::ST_Other) {
     303             : 
     304         902 :       section_iterator SI = Obj.section_end();
     305         902 :       if (auto SIOrErr = I->getSection())
     306         902 :         SI = *SIOrErr;
     307             :       else
     308             :         return SIOrErr.takeError();
     309             : 
     310         902 :       if (SI == Obj.section_end())
     311          85 :         continue;
     312             : 
     313             :       // Get symbol offset.
     314             :       uint64_t SectOffset;
     315        1634 :       if (auto Err = getOffset(*I, *SI, SectOffset))
     316             :         return std::move(Err);
     317             : 
     318         817 :       bool IsCode = SI->isText();
     319             :       unsigned SectionID;
     320         817 :       if (auto SectionIDOrErr =
     321         817 :               findOrEmitSection(Obj, *SI, IsCode, LocalSections))
     322         817 :         SectionID = *SectionIDOrErr;
     323             :       else
     324             :         return SectionIDOrErr.takeError();
     325             : 
     326             :       LLVM_DEBUG(dbgs() << "\tType: " << SymType << " Name: " << Name
     327             :                         << " SID: " << SectionID
     328             :                         << " Offset: " << format("%p", (uintptr_t)SectOffset)
     329             :                         << " flags: " << Flags << "\n");
     330         817 :       GlobalSymbolTable[Name] =
     331         817 :           SymbolTableEntry(SectionID, SectOffset, *JITSymFlags);
     332             :     }
     333             :   }
     334             : 
     335             :   // Allocate common symbols
     336         353 :   if (auto Err = emitCommonSymbols(Obj, CommonSymbolsToAllocate, CommonSize,
     337         353 :                                    CommonAlign))
     338             :     return std::move(Err);
     339             : 
     340             :   // Parse and process relocations
     341             :   LLVM_DEBUG(dbgs() << "Parse relocations:\n");
     342         353 :   for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
     343        3194 :        SI != SE; ++SI) {
     344             :     StubMap Stubs;
     345        2841 :     section_iterator RelocatedSection = SI->getRelocatedSection();
     346             : 
     347        2841 :     if (RelocatedSection == SE)
     348             :       continue;
     349             : 
     350         609 :     relocation_iterator I = SI->relocation_begin();
     351         609 :     relocation_iterator E = SI->relocation_end();
     352             : 
     353         609 :     if (I == E && !ProcessAllSections)
     354             :       continue;
     355             : 
     356         579 :     bool IsCode = RelocatedSection->isText();
     357             :     unsigned SectionID = 0;
     358         579 :     if (auto SectionIDOrErr = findOrEmitSection(Obj, *RelocatedSection, IsCode,
     359         579 :                                                 LocalSections))
     360         579 :       SectionID = *SectionIDOrErr;
     361             :     else
     362             :       return SectionIDOrErr.takeError();
     363             : 
     364             :     LLVM_DEBUG(dbgs() << "\tSectionID: " << SectionID << "\n");
     365             : 
     366        1906 :     for (; I != E;)
     367        1327 :       if (auto IOrErr = processRelocationRef(SectionID, I, Obj, LocalSections, Stubs))
     368        1327 :         I = *IOrErr;
     369             :       else
     370             :         return IOrErr.takeError();
     371             : 
     372             :     // If there is an attached checker, notify it about the stubs for this
     373             :     // section so that they can be verified.
     374         579 :     if (Checker)
     375         118 :       Checker->registerStubMap(Obj.getFileName(), SectionID, Stubs);
     376             :   }
     377             : 
     378             :   // Give the subclasses a chance to tie-up any loose ends.
     379         706 :   if (auto Err = finalizeLoad(Obj, LocalSections))
     380             :     return std::move(Err);
     381             : 
     382             : //   for (auto E : LocalSections)
     383             : //     llvm::dbgs() << "Added: " << E.first.getRawDataRefImpl() << " -> " << E.second << "\n";
     384             : 
     385             :   return LocalSections;
     386             : }
     387             : 
     388             : // A helper method for computeTotalAllocSize.
     389             : // Computes the memory size required to allocate sections with the given sizes,
     390             : // assuming that all sections are allocated with the given alignment
     391             : static uint64_t
     392             : computeAllocationSizeForSections(std::vector<uint64_t> &SectionSizes,
     393             :                                  uint64_t Alignment) {
     394             :   uint64_t TotalSize = 0;
     395         160 :   for (size_t Idx = 0, Cnt = SectionSizes.size(); Idx < Cnt; Idx++) {
     396             :     uint64_t AlignedSize =
     397          67 :         (SectionSizes[Idx] + Alignment - 1) / Alignment * Alignment;
     398          67 :     TotalSize += AlignedSize;
     399             :   }
     400             :   return TotalSize;
     401             : }
     402             : 
     403        1037 : static bool isRequiredForExecution(const SectionRef Section) {
     404        1037 :   const ObjectFile *Obj = Section.getObject();
     405        1037 :   if (isa<object::ELFObjectFileBase>(Obj))
     406         980 :     return ELFSectionRef(Section).getFlags() & ELF::SHF_ALLOC;
     407             :   if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj)) {
     408          17 :     const coff_section *CoffSection = COFFObj->getCOFFSection(Section);
     409             :     // Avoid loading zero-sized COFF sections.
     410             :     // In PE files, VirtualSize gives the section size, and SizeOfRawData
     411             :     // may be zero for sections with content. In Obj files, SizeOfRawData
     412             :     // gives the section size, and VirtualSize is always zero. Hence
     413             :     // the need to check for both cases below.
     414             :     bool HasContent =
     415          17 :         (CoffSection->VirtualSize > 0) || (CoffSection->SizeOfRawData > 0);
     416             :     bool IsDiscardable =
     417          17 :         CoffSection->Characteristics &
     418             :         (COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_LNK_INFO);
     419          17 :     return HasContent && !IsDiscardable;
     420             :   }
     421             : 
     422             :   assert(isa<MachOObjectFile>(Obj));
     423             :   return true;
     424             : }
     425             : 
     426         873 : static bool isReadOnlyData(const SectionRef Section) {
     427         873 :   const ObjectFile *Obj = Section.getObject();
     428         873 :   if (isa<object::ELFObjectFileBase>(Obj))
     429        1632 :     return !(ELFSectionRef(Section).getFlags() &
     430         816 :              (ELF::SHF_WRITE | ELF::SHF_EXECINSTR));
     431             :   if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj))
     432          17 :     return ((COFFObj->getCOFFSection(Section)->Characteristics &
     433             :              (COFF::IMAGE_SCN_CNT_INITIALIZED_DATA
     434             :              | COFF::IMAGE_SCN_MEM_READ
     435             :              | COFF::IMAGE_SCN_MEM_WRITE))
     436             :              ==
     437             :              (COFF::IMAGE_SCN_CNT_INITIALIZED_DATA
     438          17 :              | COFF::IMAGE_SCN_MEM_READ));
     439             : 
     440             :   assert(isa<MachOObjectFile>(Obj));
     441             :   return false;
     442             : }
     443             : 
     444         814 : static bool isZeroInit(const SectionRef Section) {
     445         814 :   const ObjectFile *Obj = Section.getObject();
     446         814 :   if (isa<object::ELFObjectFileBase>(Obj))
     447         757 :     return ELFSectionRef(Section).getType() == ELF::SHT_NOBITS;
     448             :   if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj))
     449          17 :     return COFFObj->getCOFFSection(Section)->Characteristics &
     450          17 :             COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA;
     451             : 
     452             :   auto *MachO = cast<MachOObjectFile>(Obj);
     453          40 :   unsigned SectionType = MachO->getSectionType(Section);
     454          40 :   return SectionType == MachO::S_ZEROFILL ||
     455          40 :          SectionType == MachO::S_GB_ZEROFILL;
     456             : }
     457             : 
     458             : // Compute an upper bound of the memory size that is required to load all
     459             : // sections
     460          31 : Error RuntimeDyldImpl::computeTotalAllocSize(const ObjectFile &Obj,
     461             :                                              uint64_t &CodeSize,
     462             :                                              uint32_t &CodeAlign,
     463             :                                              uint64_t &RODataSize,
     464             :                                              uint32_t &RODataAlign,
     465             :                                              uint64_t &RWDataSize,
     466             :                                              uint32_t &RWDataAlign) {
     467             :   // Compute the size of all sections required for execution
     468             :   std::vector<uint64_t> CodeSectionSizes;
     469             :   std::vector<uint64_t> ROSectionSizes;
     470             :   std::vector<uint64_t> RWSectionSizes;
     471             : 
     472             :   // Collect sizes of all sections to be loaded;
     473             :   // also determine the max alignment of all sections
     474          31 :   for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
     475         254 :        SI != SE; ++SI) {
     476             :     const SectionRef &Section = *SI;
     477             : 
     478         223 :     bool IsRequired = isRequiredForExecution(Section) || ProcessAllSections;
     479             : 
     480             :     // Consider only the sections that are required to be loaded for execution
     481             :     if (IsRequired) {
     482          59 :       uint64_t DataSize = Section.getSize();
     483          59 :       uint64_t Alignment64 = Section.getAlignment();
     484          59 :       unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
     485          59 :       bool IsCode = Section.isText();
     486          59 :       bool IsReadOnly = isReadOnlyData(Section);
     487             : 
     488          59 :       StringRef Name;
     489          59 :       if (auto EC = Section.getName(Name))
     490           0 :         return errorCodeToError(EC);
     491             : 
     492          59 :       uint64_t StubBufSize = computeSectionStubBufSize(Obj, Section);
     493          59 :       uint64_t SectionSize = DataSize + StubBufSize;
     494             : 
     495             :       // The .eh_frame section (at least on Linux) needs an extra four bytes
     496             :       // padded
     497             :       // with zeroes added at the end.  For MachO objects, this section has a
     498             :       // slightly different name, so this won't have any effect for MachO
     499             :       // objects.
     500             :       if (Name == ".eh_frame")
     501           5 :         SectionSize += 4;
     502             : 
     503          59 :       if (!SectionSize)
     504           0 :         SectionSize = 1;
     505             : 
     506          59 :       if (IsCode) {
     507          31 :         CodeAlign = std::max(CodeAlign, Alignment);
     508          31 :         CodeSectionSizes.push_back(SectionSize);
     509          28 :       } else if (IsReadOnly) {
     510          17 :         RODataAlign = std::max(RODataAlign, Alignment);
     511          17 :         ROSectionSizes.push_back(SectionSize);
     512             :       } else {
     513          11 :         RWDataAlign = std::max(RWDataAlign, Alignment);
     514          11 :         RWSectionSizes.push_back(SectionSize);
     515             :       }
     516             :     }
     517             :   }
     518             : 
     519             :   // Compute Global Offset Table size. If it is not zero we
     520             :   // also update alignment, which is equal to a size of a
     521             :   // single GOT entry.
     522          31 :   if (unsigned GotSize = computeGOTSize(Obj)) {
     523           4 :     RWSectionSizes.push_back(GotSize);
     524           6 :     RWDataAlign = std::max<uint32_t>(RWDataAlign, getGOTEntrySize());
     525             :   }
     526             : 
     527             :   // Compute the size of all common symbols
     528          31 :   uint64_t CommonSize = 0;
     529          31 :   uint32_t CommonAlign = 1;
     530         205 :   for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
     531             :        ++I) {
     532         174 :     uint32_t Flags = I->getFlags();
     533         174 :     if (Flags & SymbolRef::SF_Common) {
     534             :       // Add the common symbols to a list.  We'll allocate them all below.
     535             :       uint64_t Size = I->getCommonSize();
     536             :       uint32_t Align = I->getAlignment();
     537             :       // If this is the first common symbol, use its alignment as the alignment
     538             :       // for the common symbols section.
     539           8 :       if (CommonSize == 0)
     540           4 :         CommonAlign = Align;
     541          16 :       CommonSize = alignTo(CommonSize, Align) + Size;
     542             :     }
     543             :   }
     544          31 :   if (CommonSize != 0) {
     545           4 :     RWSectionSizes.push_back(CommonSize);
     546           4 :     RWDataAlign = std::max(RWDataAlign, CommonAlign);
     547             :   }
     548             : 
     549             :   // Compute the required allocation space for each different type of sections
     550             :   // (code, read-only data, read-write data) assuming that all sections are
     551             :   // allocated with the max alignment. Note that we cannot compute with the
     552             :   // individual alignments of the sections, because then the required size
     553             :   // depends on the order, in which the sections are allocated.
     554          31 :   CodeSize = computeAllocationSizeForSections(CodeSectionSizes, CodeAlign);
     555          31 :   RODataSize = computeAllocationSizeForSections(ROSectionSizes, RODataAlign);
     556          62 :   RWDataSize = computeAllocationSizeForSections(RWSectionSizes, RWDataAlign);
     557             : 
     558             :   return Error::success();
     559             : }
     560             : 
     561             : // compute GOT size
     562          31 : unsigned RuntimeDyldImpl::computeGOTSize(const ObjectFile &Obj) {
     563          31 :   size_t GotEntrySize = getGOTEntrySize();
     564          31 :   if (!GotEntrySize)
     565             :     return 0;
     566             : 
     567             :   size_t GotSize = 0;
     568          31 :   for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
     569         254 :        SI != SE; ++SI) {
     570             : 
     571         321 :     for (const RelocationRef &Reloc : SI->relocations())
     572          98 :       if (relocationNeedsGot(Reloc))
     573           6 :         GotSize += GotEntrySize;
     574             :   }
     575             : 
     576          31 :   return GotSize;
     577             : }
     578             : 
     579             : // compute stub buffer size for the given section
     580         873 : unsigned RuntimeDyldImpl::computeSectionStubBufSize(const ObjectFile &Obj,
     581             :                                                     const SectionRef &Section) {
     582         873 :   unsigned StubSize = getMaxStubSize();
     583         873 :   if (StubSize == 0) {
     584             :     return 0;
     585             :   }
     586             :   // FIXME: this is an inefficient way to handle this. We should computed the
     587             :   // necessary section allocation size in loadObject by walking all the sections
     588             :   // once.
     589             :   unsigned StubBufSize = 0;
     590         864 :   for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
     591        8773 :        SI != SE; ++SI) {
     592        7909 :     section_iterator RelSecI = SI->getRelocatedSection();
     593       15818 :     if (!(RelSecI == Section))
     594        7292 :       continue;
     595             : 
     596        2043 :     for (const RelocationRef &Reloc : SI->relocations())
     597        1426 :       if (relocationNeedsStub(Reloc))
     598         421 :         StubBufSize += StubSize;
     599             :   }
     600             : 
     601             :   // Get section data size and alignment
     602         864 :   uint64_t DataSize = Section.getSize();
     603         864 :   uint64_t Alignment64 = Section.getAlignment();
     604             : 
     605             :   // Add stubbuf size alignment
     606         864 :   unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
     607         864 :   unsigned StubAlignment = getStubAlignment();
     608         864 :   unsigned EndAlignment = (DataSize | Alignment) & -(DataSize | Alignment);
     609         864 :   if (StubAlignment > EndAlignment)
     610           4 :     StubBufSize += StubAlignment - EndAlignment;
     611             :   return StubBufSize;
     612             : }
     613             : 
     614         393 : uint64_t RuntimeDyldImpl::readBytesUnaligned(uint8_t *Src,
     615             :                                              unsigned Size) const {
     616             :   uint64_t Result = 0;
     617         393 :   if (IsTargetLittleEndian) {
     618         282 :     Src += Size - 1;
     619        1600 :     while (Size--)
     620        1318 :       Result = (Result << 8) | *Src--;
     621             :   } else
     622         587 :     while (Size--)
     623         476 :       Result = (Result << 8) | *Src++;
     624             : 
     625         393 :   return Result;
     626             : }
     627             : 
     628         259 : void RuntimeDyldImpl::writeBytesUnaligned(uint64_t Value, uint8_t *Dst,
     629             :                                           unsigned Size) const {
     630         259 :   if (IsTargetLittleEndian) {
     631        1012 :     while (Size--) {
     632         836 :       *Dst++ = Value & 0xFF;
     633         836 :       Value >>= 8;
     634             :     }
     635             :   } else {
     636          83 :     Dst += Size - 1;
     637         439 :     while (Size--) {
     638         356 :       *Dst-- = Value & 0xFF;
     639         356 :       Value >>= 8;
     640             :     }
     641             :   }
     642         259 : }
     643             : 
     644             : Expected<JITSymbolFlags>
     645        1714 : RuntimeDyldImpl::getJITSymbolFlags(const SymbolRef &SR) {
     646        1714 :   return JITSymbolFlags::fromObjectSymbol(SR);
     647             : }
     648             : 
     649         353 : Error RuntimeDyldImpl::emitCommonSymbols(const ObjectFile &Obj,
     650             :                                          CommonSymbolList &SymbolsToAllocate,
     651             :                                          uint64_t CommonSize,
     652             :                                          uint32_t CommonAlign) {
     653         353 :   if (SymbolsToAllocate.empty())
     654             :     return Error::success();
     655             : 
     656             :   // Allocate memory for the section
     657          25 :   unsigned SectionID = Sections.size();
     658          25 :   uint8_t *Addr = MemMgr.allocateDataSection(CommonSize, CommonAlign, SectionID,
     659          25 :                                              "<common symbols>", false);
     660          25 :   if (!Addr)
     661           0 :     report_fatal_error("Unable to allocate memory for common symbols!");
     662             :   uint64_t Offset = 0;
     663          25 :   Sections.push_back(
     664          25 :       SectionEntry("<common symbols>", Addr, CommonSize, CommonSize, 0));
     665          25 :   memset(Addr, 0, CommonSize);
     666             : 
     667             :   LLVM_DEBUG(dbgs() << "emitCommonSection SectionID: " << SectionID
     668             :                     << " new addr: " << format("%p", Addr)
     669             :                     << " DataSize: " << CommonSize << "\n");
     670             : 
     671             :   // Assign the address of each symbol
     672         110 :   for (auto &Sym : SymbolsToAllocate) {
     673             :     uint32_t Align = Sym.getAlignment();
     674             :     uint64_t Size = Sym.getCommonSize();
     675             :     StringRef Name;
     676          85 :     if (auto NameOrErr = Sym.getName())
     677          85 :       Name = *NameOrErr;
     678             :     else
     679             :       return NameOrErr.takeError();
     680          85 :     if (Align) {
     681             :       // This symbol has an alignment requirement.
     682          85 :       uint64_t AlignOffset = OffsetToAlignment((uint64_t)Addr, Align);
     683          85 :       Addr += AlignOffset;
     684          85 :       Offset += AlignOffset;
     685             :     }
     686          85 :     auto JITSymFlags = getJITSymbolFlags(Sym);
     687             : 
     688          85 :     if (!JITSymFlags)
     689             :       return JITSymFlags.takeError();
     690             : 
     691             :     LLVM_DEBUG(dbgs() << "Allocating common symbol " << Name << " address "
     692             :                       << format("%p", Addr) << "\n");
     693          85 :     GlobalSymbolTable[Name] =
     694             :         SymbolTableEntry(SectionID, Offset, std::move(*JITSymFlags));
     695          85 :     Offset += Size;
     696          85 :     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         814 : RuntimeDyldImpl::emitSection(const ObjectFile &Obj,
     707             :                              const SectionRef &Section,
     708             :                              bool IsCode) {
     709         814 :   StringRef data;
     710         814 :   uint64_t Alignment64 = Section.getAlignment();
     711             : 
     712         814 :   unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
     713             :   unsigned PaddingSize = 0;
     714             :   unsigned StubBufSize = 0;
     715         814 :   bool IsRequired = isRequiredForExecution(Section);
     716         814 :   bool IsVirtual = Section.isVirtual();
     717         814 :   bool IsZeroInit = isZeroInit(Section);
     718         814 :   bool IsReadOnly = isReadOnlyData(Section);
     719         814 :   uint64_t DataSize = Section.getSize();
     720             : 
     721         814 :   StringRef Name;
     722         814 :   if (auto EC = Section.getName(Name))
     723           0 :     return errorCodeToError(EC);
     724             : 
     725         814 :   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         814 :   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         814 :   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         789 :     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         814 :   if (IsCode) {
     752         344 :     Alignment = std::max(Alignment, getStubAlignment());
     753         344 :     if (StubBufSize > 0)
     754          43 :       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         814 :   if (IsRequired || ProcessAllSections) {
     760         796 :     Allocate = DataSize + PaddingSize + StubBufSize;
     761         796 :     if (!Allocate)
     762             :       Allocate = 1;
     763         796 :     Addr = IsCode ? MemMgr.allocateCodeSection(Allocate, Alignment, SectionID,
     764         344 :                                                Name)
     765         904 :                   : MemMgr.allocateDataSection(Allocate, Alignment, SectionID,
     766         452 :                                                Name, IsReadOnly);
     767         796 :     if (!Addr)
     768           0 :       report_fatal_error("Unable to allocate section memory!");
     769             : 
     770             :     // Zero-initialize or copy the data from the image
     771         796 :     if (IsZeroInit || IsVirtual)
     772          25 :       memset(Addr, 0, DataSize);
     773             :     else
     774         771 :       memcpy(Addr, pData, DataSize);
     775             : 
     776             :     // Fill in any extra bytes we allocated for padding
     777         796 :     if (PaddingSize != 0) {
     778         253 :       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         253 :       if (StubBufSize > 0)
     785          19 :         DataSize &= ~(getStubAlignment() - 1);
     786             :     }
     787             : 
     788             :     LLVM_DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: "
     789             :                       << Name << " obj addr: " << format("%p", pData)
     790             :                       << " new addr: " << format("%p", Addr) << " DataSize: "
     791             :                       << 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             :     LLVM_DEBUG(
     800             :         dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
     801             :                << " obj addr: " << format("%p", data.data()) << " new addr: 0"
     802             :                << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
     803             :                << " Allocate: " << Allocate << "\n");
     804             :   }
     805             : 
     806         814 :   Sections.push_back(
     807         814 :       SectionEntry(Name, Addr, DataSize, Allocate, (uintptr_t)pData));
     808             : 
     809             :   // Debug info sections are linked as if their load address was zero
     810         814 :   if (!IsRequired)
     811             :     Sections.back().setLoadAddress(0);
     812             : 
     813         814 :   if (Checker)
     814         152 :     Checker->registerSection(Obj.getFileName(), SectionID);
     815             : 
     816             :   return SectionID;
     817             : }
     818             : 
     819             : Expected<unsigned>
     820        2173 : RuntimeDyldImpl::findOrEmitSection(const ObjectFile &Obj,
     821             :                                    const SectionRef &Section,
     822             :                                    bool IsCode,
     823             :                                    ObjSectionToIDMap &LocalSections) {
     824             : 
     825             :   unsigned SectionID = 0;
     826             :   ObjSectionToIDMap::iterator i = LocalSections.find(Section);
     827        2173 :   if (i != LocalSections.end())
     828        1359 :     SectionID = i->second;
     829             :   else {
     830         814 :     if (auto SectionIDOrErr = emitSection(Obj, Section, IsCode))
     831         814 :       SectionID = *SectionIDOrErr;
     832             :     else
     833             :       return SectionIDOrErr.takeError();
     834         814 :     LocalSections[Section] = SectionID;
     835             :   }
     836             :   return SectionID;
     837             : }
     838             : 
     839        1094 : void RuntimeDyldImpl::addRelocationForSection(const RelocationEntry &RE,
     840             :                                               unsigned SectionID) {
     841        1094 :   Relocations[SectionID].push_back(RE);
     842        1094 : }
     843             : 
     844         294 : void RuntimeDyldImpl::addRelocationForSymbol(const RelocationEntry &RE,
     845             :                                              StringRef SymbolName) {
     846             :   // Relocation by symbol.  If the symbol is found in the global symbol table,
     847             :   // create an appropriate section relocation.  Otherwise, add it to
     848             :   // ExternalSymbolRelocations.
     849         294 :   RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(SymbolName);
     850         588 :   if (Loc == GlobalSymbolTable.end()) {
     851         291 :     ExternalSymbolRelocations[SymbolName].push_back(RE);
     852             :   } else {
     853             :     // Copy the RE since we want to modify its addend.
     854           3 :     RelocationEntry RECopy = RE;
     855             :     const auto &SymInfo = Loc->second;
     856           3 :     RECopy.Addend += SymInfo.getOffset();
     857           3 :     Relocations[SymInfo.getSectionID()].push_back(RECopy);
     858             :   }
     859         294 : }
     860             : 
     861          21 : uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr,
     862             :                                              unsigned AbiVariant) {
     863          21 :   if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be) {
     864             :     // This stub has to be able to access the full address space,
     865             :     // since symbol lookup won't necessarily find a handy, in-range,
     866             :     // PLT stub for functions which could be anywhere.
     867             :     // Stub can use ip0 (== x16) to calculate address
     868           0 :     writeBytesUnaligned(0xd2e00010, Addr,    4); // movz ip0, #:abs_g3:<addr>
     869           0 :     writeBytesUnaligned(0xf2c00010, Addr+4,  4); // movk ip0, #:abs_g2_nc:<addr>
     870           0 :     writeBytesUnaligned(0xf2a00010, Addr+8,  4); // movk ip0, #:abs_g1_nc:<addr>
     871           0 :     writeBytesUnaligned(0xf2800010, Addr+12, 4); // movk ip0, #:abs_g0_nc:<addr>
     872           0 :     writeBytesUnaligned(0xd61f0200, Addr+16, 4); // br ip0
     873             : 
     874           0 :     return Addr;
     875          21 :   } else if (Arch == Triple::arm || Arch == Triple::armeb) {
     876             :     // TODO: There is only ARM far stub now. We should add the Thumb stub,
     877             :     // and stubs for branches Thumb - ARM and ARM - Thumb.
     878           0 :     writeBytesUnaligned(0xe51ff004, Addr, 4); // ldr pc, [pc, #-4]
     879           0 :     return Addr + 4;
     880          21 :   } else if (IsMipsO32ABI || IsMipsN32ABI) {
     881             :     // 0:   3c190000        lui     t9,%hi(addr).
     882             :     // 4:   27390000        addiu   t9,t9,%lo(addr).
     883             :     // 8:   03200008        jr      t9.
     884             :     // c:   00000000        nop.
     885             :     const unsigned LuiT9Instr = 0x3c190000, AdduiT9Instr = 0x27390000;
     886             :     const unsigned NopInstr = 0x0;
     887             :     unsigned JrT9Instr = 0x03200008;
     888           4 :     if ((AbiVariant & ELF::EF_MIPS_ARCH) == ELF::EF_MIPS_ARCH_32R6 ||
     889             :         (AbiVariant & ELF::EF_MIPS_ARCH) == ELF::EF_MIPS_ARCH_64R6)
     890             :       JrT9Instr = 0x03200009;
     891             : 
     892           4 :     writeBytesUnaligned(LuiT9Instr, Addr, 4);
     893           4 :     writeBytesUnaligned(AdduiT9Instr, Addr + 4, 4);
     894           4 :     writeBytesUnaligned(JrT9Instr, Addr + 8, 4);
     895           4 :     writeBytesUnaligned(NopInstr, Addr + 12, 4);
     896           4 :     return Addr;
     897          17 :   } else if (IsMipsN64ABI) {
     898             :     // 0:   3c190000        lui     t9,%highest(addr).
     899             :     // 4:   67390000        daddiu  t9,t9,%higher(addr).
     900             :     // 8:   0019CC38        dsll    t9,t9,16.
     901             :     // c:   67390000        daddiu  t9,t9,%hi(addr).
     902             :     // 10:  0019CC38        dsll    t9,t9,16.
     903             :     // 14:  67390000        daddiu  t9,t9,%lo(addr).
     904             :     // 18:  03200008        jr      t9.
     905             :     // 1c:  00000000        nop.
     906             :     const unsigned LuiT9Instr = 0x3c190000, DaddiuT9Instr = 0x67390000,
     907             :                    DsllT9Instr = 0x19CC38;
     908             :     const unsigned NopInstr = 0x0;
     909             :     unsigned JrT9Instr = 0x03200008;
     910           2 :     if ((AbiVariant & ELF::EF_MIPS_ARCH) == ELF::EF_MIPS_ARCH_64R6)
     911             :       JrT9Instr = 0x03200009;
     912             : 
     913           2 :     writeBytesUnaligned(LuiT9Instr, Addr, 4);
     914           2 :     writeBytesUnaligned(DaddiuT9Instr, Addr + 4, 4);
     915           2 :     writeBytesUnaligned(DsllT9Instr, Addr + 8, 4);
     916           2 :     writeBytesUnaligned(DaddiuT9Instr, Addr + 12, 4);
     917           2 :     writeBytesUnaligned(DsllT9Instr, Addr + 16, 4);
     918           2 :     writeBytesUnaligned(DaddiuT9Instr, Addr + 20, 4);
     919           2 :     writeBytesUnaligned(JrT9Instr, Addr + 24, 4);
     920           2 :     writeBytesUnaligned(NopInstr, Addr + 28, 4);
     921           2 :     return Addr;
     922          15 :   } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
     923             :     // Depending on which version of the ELF ABI is in use, we need to
     924             :     // generate one of two variants of the stub.  They both start with
     925             :     // the same sequence to load the target address into r12.
     926           3 :     writeInt32BE(Addr,    0x3D800000); // lis   r12, highest(addr)
     927           3 :     writeInt32BE(Addr+4,  0x618C0000); // ori   r12, higher(addr)
     928           3 :     writeInt32BE(Addr+8,  0x798C07C6); // sldi  r12, r12, 32
     929           3 :     writeInt32BE(Addr+12, 0x658C0000); // oris  r12, r12, h(addr)
     930           3 :     writeInt32BE(Addr+16, 0x618C0000); // ori   r12, r12, l(addr)
     931           3 :     if (AbiVariant == 2) {
     932             :       // PowerPC64 stub ELFv2 ABI: The address points to the function itself.
     933             :       // The address is already in r12 as required by the ABI.  Branch to it.
     934           3 :       writeInt32BE(Addr+20, 0xF8410018); // std   r2,  24(r1)
     935           3 :       writeInt32BE(Addr+24, 0x7D8903A6); // mtctr r12
     936           3 :       writeInt32BE(Addr+28, 0x4E800420); // bctr
     937             :     } else {
     938             :       // PowerPC64 stub ELFv1 ABI: The address points to a function descriptor.
     939             :       // Load the function address on r11 and sets it to control register. Also
     940             :       // loads the function TOC in r2 and environment pointer to r11.
     941           0 :       writeInt32BE(Addr+20, 0xF8410028); // std   r2,  40(r1)
     942           0 :       writeInt32BE(Addr+24, 0xE96C0000); // ld    r11, 0(r12)
     943           0 :       writeInt32BE(Addr+28, 0xE84C0008); // ld    r2,  0(r12)
     944           0 :       writeInt32BE(Addr+32, 0x7D6903A6); // mtctr r11
     945           0 :       writeInt32BE(Addr+36, 0xE96C0010); // ld    r11, 16(r2)
     946           0 :       writeInt32BE(Addr+40, 0x4E800420); // bctr
     947             :     }
     948           3 :     return Addr;
     949          12 :   } else if (Arch == Triple::systemz) {
     950             :     writeInt16BE(Addr,    0xC418);     // lgrl %r1,.+8
     951             :     writeInt16BE(Addr+2,  0x0000);
     952             :     writeInt16BE(Addr+4,  0x0004);
     953             :     writeInt16BE(Addr+6,  0x07F1);     // brc 15,%r1
     954             :     // 8-byte address stored at Addr + 8
     955           0 :     return Addr;
     956          12 :   } else if (Arch == Triple::x86_64) {
     957          11 :     *Addr      = 0xFF; // jmp
     958          11 :     *(Addr+1)  = 0x25; // rip
     959             :     // 32-bit PC-relative address of the GOT entry will be stored at Addr+2
     960           1 :   } else if (Arch == Triple::x86) {
     961           1 :     *Addr      = 0xE9; // 32-bit pc-relative jump.
     962             :   }
     963             :   return Addr;
     964             : }
     965             : 
     966             : // Assign an address to a symbol name and resolve all the relocations
     967             : // associated with it.
     968         218 : void RuntimeDyldImpl::reassignSectionAddress(unsigned SectionID,
     969             :                                              uint64_t Addr) {
     970             :   // The address to use for relocation resolution is not
     971             :   // the address of the local section buffer. We must be doing
     972             :   // a remote execution environment of some sort. Relocations can't
     973             :   // be applied until all the sections have been moved.  The client must
     974             :   // trigger this with a call to MCJIT::finalize() or
     975             :   // RuntimeDyld::resolveRelocations().
     976             :   //
     977             :   // Addr is a uint64_t because we can't assume the pointer width
     978             :   // of the target is the same as that of the host. Just use a generic
     979             :   // "big enough" type.
     980             :   LLVM_DEBUG(
     981             :       dbgs() << "Reassigning address for section " << SectionID << " ("
     982             :              << Sections[SectionID].getName() << "): "
     983             :              << format("0x%016" PRIx64, Sections[SectionID].getLoadAddress())
     984             :              << " -> " << format("0x%016" PRIx64, Addr) << "\n");
     985         218 :   Sections[SectionID].setLoadAddress(Addr);
     986         218 : }
     987             : 
     988         685 : void RuntimeDyldImpl::resolveRelocationList(const RelocationList &Relocs,
     989             :                                             uint64_t Value) {
     990        2069 :   for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
     991        1384 :     const RelocationEntry &RE = Relocs[i];
     992             :     // Ignore relocations for sections that were not loaded
     993        2768 :     if (Sections[RE.SectionID].getAddress() == nullptr)
     994             :       continue;
     995        1194 :     resolveRelocation(RE, Value);
     996             :   }
     997         685 : }
     998             : 
     999         480 : Error RuntimeDyldImpl::resolveExternalSymbols() {
    1000         480 :   StringMap<JITEvaluatedSymbol> ExternalSymbolMap;
    1001             : 
    1002             :   // Resolution can trigger emission of more symbols, so iterate until
    1003             :   // we've resolved *everything*.
    1004             :   {
    1005             :     JITSymbolResolver::LookupSet ResolvedSymbols;
    1006             : 
    1007             :     while (true) {
    1008             :       JITSymbolResolver::LookupSet NewSymbols;
    1009             : 
    1010        1517 :       for (auto &RelocKV : ExternalSymbolRelocations) {
    1011         369 :         StringRef Name = RelocKV.first();
    1012         738 :         if (!Name.empty() && !GlobalSymbolTable.count(Name) &&
    1013             :             !ResolvedSymbols.count(Name))
    1014             :           NewSymbols.insert(Name);
    1015             :       }
    1016             : 
    1017         574 :       if (NewSymbols.empty())
    1018             :         break;
    1019             : 
    1020         188 :       auto NewResolverResults = Resolver.lookup(NewSymbols);
    1021          94 :       if (!NewResolverResults)
    1022           0 :         return NewResolverResults.takeError();
    1023             : 
    1024             :       assert(NewResolverResults->size() == NewSymbols.size() &&
    1025             :              "Should have errored on unresolved symbols");
    1026             : 
    1027         263 :       for (auto &RRKV : *NewResolverResults) {
    1028             :         assert(!ResolvedSymbols.count(RRKV.first) && "Redundant resolution?");
    1029         169 :         ExternalSymbolMap.insert(RRKV);
    1030         169 :         ResolvedSymbols.insert(RRKV.first);
    1031             :       }
    1032             :     }
    1033             :   }
    1034             : 
    1035         676 :   while (!ExternalSymbolRelocations.empty()) {
    1036             : 
    1037         196 :     StringMap<RelocationList>::iterator i = ExternalSymbolRelocations.begin();
    1038             : 
    1039         196 :     StringRef Name = i->first();
    1040         196 :     if (Name.size() == 0) {
    1041             :       // This is an absolute symbol, use an address of zero.
    1042             :       LLVM_DEBUG(dbgs() << "Resolving absolute relocations."
    1043             :                         << "\n");
    1044           0 :       RelocationList &Relocs = i->second;
    1045           0 :       resolveRelocationList(Relocs, 0);
    1046             :     } else {
    1047             :       uint64_t Addr = 0;
    1048         196 :       JITSymbolFlags Flags;
    1049         196 :       RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(Name);
    1050         392 :       if (Loc == GlobalSymbolTable.end()) {
    1051         157 :         auto RRI = ExternalSymbolMap.find(Name);
    1052             :         assert(RRI != ExternalSymbolMap.end() && "No result for symbol");
    1053         157 :         Addr = RRI->second.getAddress();
    1054         157 :         Flags = RRI->second.getFlags();
    1055             :         // The call to getSymbolAddress may have caused additional modules to
    1056             :         // be loaded, which may have added new entries to the
    1057             :         // ExternalSymbolRelocations map.  Consquently, we need to update our
    1058             :         // iterator.  This is also why retrieval of the relocation list
    1059             :         // associated with this symbol is deferred until below this point.
    1060             :         // New entries may have been added to the relocation list.
    1061         157 :         i = ExternalSymbolRelocations.find(Name);
    1062             :       } else {
    1063             :         // We found the symbol in our global table.  It was probably in a
    1064             :         // Module that we loaded previously.
    1065             :         const auto &SymInfo = Loc->second;
    1066          39 :         Addr = getSectionLoadAddress(SymInfo.getSectionID()) +
    1067          39 :                SymInfo.getOffset();
    1068          39 :         Flags = SymInfo.getFlags();
    1069             :       }
    1070             : 
    1071             :       // FIXME: Implement error handling that doesn't kill the host program!
    1072         196 :       if (!Addr)
    1073           0 :         report_fatal_error("Program used external function '" + Name +
    1074             :                            "' which could not be resolved!");
    1075             : 
    1076             :       // If Resolver returned UINT64_MAX, the client wants to handle this symbol
    1077             :       // manually and we shouldn't resolve its relocations.
    1078         196 :       if (Addr != UINT64_MAX) {
    1079             : 
    1080             :         // Tweak the address based on the symbol flags if necessary.
    1081             :         // For example, this is used by RuntimeDyldMachOARM to toggle the low bit
    1082             :         // if the target symbol is Thumb.
    1083         192 :         Addr = modifyAddressBasedOnFlags(Addr, Flags);
    1084             : 
    1085             :         LLVM_DEBUG(dbgs() << "Resolving relocations Name: " << Name << "\t"
    1086             :                           << format("0x%lx", Addr) << "\n");
    1087             :         // This list may have been updated when we called getSymbolAddress, so
    1088             :         // don't change this code to get the list earlier.
    1089         192 :         RelocationList &Relocs = i->second;
    1090         192 :         resolveRelocationList(Relocs, Addr);
    1091             :       }
    1092             :     }
    1093             : 
    1094             :     ExternalSymbolRelocations.erase(i);
    1095             :   }
    1096             : 
    1097             :   return Error::success();
    1098             : }
    1099             : 
    1100             : //===----------------------------------------------------------------------===//
    1101             : // RuntimeDyld class implementation
    1102             : 
    1103        1102 : uint64_t RuntimeDyld::LoadedObjectInfo::getSectionLoadAddress(
    1104             :                                           const object::SectionRef &Sec) const {
    1105             : 
    1106             :   auto I = ObjSecToIDMap.find(Sec);
    1107        1102 :   if (I != ObjSecToIDMap.end())
    1108         780 :     return RTDyld.Sections[I->second].getLoadAddress();
    1109             : 
    1110             :   return 0;
    1111             : }
    1112             : 
    1113           0 : void RuntimeDyld::MemoryManager::anchor() {}
    1114           0 : void JITSymbolResolver::anchor() {}
    1115           0 : void LegacyJITSymbolResolver::anchor() {}
    1116             : 
    1117         309 : RuntimeDyld::RuntimeDyld(RuntimeDyld::MemoryManager &MemMgr,
    1118         309 :                          JITSymbolResolver &Resolver)
    1119         309 :     : MemMgr(MemMgr), Resolver(Resolver) {
    1120             :   // FIXME: There's a potential issue lurking here if a single instance of
    1121             :   // RuntimeDyld is used to load multiple objects.  The current implementation
    1122             :   // associates a single memory manager with a RuntimeDyld instance.  Even
    1123             :   // though the public class spawns a new 'impl' instance for each load,
    1124             :   // they share a single memory manager.  This can become a problem when page
    1125             :   // permissions are applied.
    1126             :   Dyld = nullptr;
    1127         309 :   ProcessAllSections = false;
    1128         309 :   Checker = nullptr;
    1129         309 : }
    1130             : 
    1131         237 : RuntimeDyld::~RuntimeDyld() {}
    1132             : 
    1133             : static std::unique_ptr<RuntimeDyldCOFF>
    1134             : createRuntimeDyldCOFF(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM,
    1135             :                       JITSymbolResolver &Resolver, bool ProcessAllSections,
    1136             :                       RuntimeDyldCheckerImpl *Checker) {
    1137             :   std::unique_ptr<RuntimeDyldCOFF> Dyld =
    1138           4 :     RuntimeDyldCOFF::create(Arch, MM, Resolver);
    1139             :   Dyld->setProcessAllSections(ProcessAllSections);
    1140             :   Dyld->setRuntimeDyldChecker(Checker);
    1141             :   return Dyld;
    1142             : }
    1143             : 
    1144             : static std::unique_ptr<RuntimeDyldELF>
    1145             : createRuntimeDyldELF(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM,
    1146             :                      JITSymbolResolver &Resolver, bool ProcessAllSections,
    1147             :                      RuntimeDyldCheckerImpl *Checker) {
    1148             :   std::unique_ptr<RuntimeDyldELF> Dyld =
    1149         287 :       RuntimeDyldELF::create(Arch, MM, Resolver);
    1150             :   Dyld->setProcessAllSections(ProcessAllSections);
    1151             :   Dyld->setRuntimeDyldChecker(Checker);
    1152             :   return Dyld;
    1153             : }
    1154             : 
    1155             : static std::unique_ptr<RuntimeDyldMachO>
    1156             : createRuntimeDyldMachO(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM,
    1157             :                        JITSymbolResolver &Resolver,
    1158             :                        bool ProcessAllSections,
    1159             :                        RuntimeDyldCheckerImpl *Checker) {
    1160             :   std::unique_ptr<RuntimeDyldMachO> Dyld =
    1161          11 :     RuntimeDyldMachO::create(Arch, MM, Resolver);
    1162             :   Dyld->setProcessAllSections(ProcessAllSections);
    1163             :   Dyld->setRuntimeDyldChecker(Checker);
    1164             :   return Dyld;
    1165             : }
    1166             : 
    1167             : std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
    1168         353 : RuntimeDyld::loadObject(const ObjectFile &Obj) {
    1169         353 :   if (!Dyld) {
    1170         604 :     if (Obj.isELF())
    1171             :       Dyld =
    1172         287 :           createRuntimeDyldELF(static_cast<Triple::ArchType>(Obj.getArch()),
    1173         287 :                                MemMgr, Resolver, ProcessAllSections, Checker);
    1174          15 :     else if (Obj.isMachO())
    1175          11 :       Dyld = createRuntimeDyldMachO(
    1176          11 :                static_cast<Triple::ArchType>(Obj.getArch()), MemMgr, Resolver,
    1177          11 :                ProcessAllSections, Checker);
    1178           4 :     else if (Obj.isCOFF())
    1179           4 :       Dyld = createRuntimeDyldCOFF(
    1180           4 :                static_cast<Triple::ArchType>(Obj.getArch()), MemMgr, Resolver,
    1181           4 :                ProcessAllSections, Checker);
    1182             :     else
    1183           0 :       report_fatal_error("Incompatible object format!");
    1184             :   }
    1185             : 
    1186         353 :   if (!Dyld->isCompatibleFile(Obj))
    1187           0 :     report_fatal_error("Incompatible object format!");
    1188             : 
    1189         353 :   auto LoadedObjInfo = Dyld->loadObject(Obj);
    1190         353 :   MemMgr.notifyObjectLoaded(*this, Obj);
    1191         353 :   return LoadedObjInfo;
    1192             : }
    1193             : 
    1194           0 : void *RuntimeDyld::getSymbolLocalAddress(StringRef Name) const {
    1195           0 :   if (!Dyld)
    1196             :     return nullptr;
    1197           0 :   return Dyld->getSymbolLocalAddress(Name);
    1198             : }
    1199             : 
    1200         386 : JITEvaluatedSymbol RuntimeDyld::getSymbol(StringRef Name) const {
    1201         386 :   if (!Dyld)
    1202             :     return nullptr;
    1203         352 :   return Dyld->getSymbol(Name);
    1204             : }
    1205             : 
    1206         136 : std::map<StringRef, JITEvaluatedSymbol> RuntimeDyld::getSymbolTable() const {
    1207         136 :   if (!Dyld)
    1208           0 :     return std::map<StringRef, JITEvaluatedSymbol>();
    1209         136 :   return Dyld->getSymbolTable();
    1210             : }
    1211             : 
    1212         960 : void RuntimeDyld::resolveRelocations() { Dyld->resolveRelocations(); }
    1213             : 
    1214           0 : void RuntimeDyld::reassignSectionAddress(unsigned SectionID, uint64_t Addr) {
    1215           0 :   Dyld->reassignSectionAddress(SectionID, Addr);
    1216           0 : }
    1217             : 
    1218         218 : void RuntimeDyld::mapSectionAddress(const void *LocalAddress,
    1219             :                                     uint64_t TargetAddress) {
    1220         218 :   Dyld->mapSectionAddress(LocalAddress, TargetAddress);
    1221         218 : }
    1222             : 
    1223         790 : bool RuntimeDyld::hasError() { return Dyld->hasError(); }
    1224             : 
    1225           0 : StringRef RuntimeDyld::getErrorString() { return Dyld->getErrorString(); }
    1226             : 
    1227         136 : void RuntimeDyld::finalizeWithMemoryManagerLocking() {
    1228         136 :   bool MemoryFinalizationLocked = MemMgr.FinalizationLocked;
    1229         136 :   MemMgr.FinalizationLocked = true;
    1230         136 :   resolveRelocations();
    1231         136 :   registerEHFrames();
    1232         136 :   if (!MemoryFinalizationLocked) {
    1233         118 :     MemMgr.finalizeMemory();
    1234         118 :     MemMgr.FinalizationLocked = false;
    1235             :   }
    1236         136 : }
    1237             : 
    1238         473 : void RuntimeDyld::registerEHFrames() {
    1239         473 :   if (Dyld)
    1240         473 :     Dyld->registerEHFrames();
    1241         473 : }
    1242             : 
    1243          49 : void RuntimeDyld::deregisterEHFrames() {
    1244          49 :   if (Dyld)
    1245          46 :     Dyld->deregisterEHFrames();
    1246          49 : }
    1247             : 
    1248             : } // end namespace llvm

Generated by: LCOV version 1.13