--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/ExecutionEngine/JITLink/EHFrameSupport.cpp	Wed Aug 14 19:46:37 2019 +0900
@@ -0,0 +1,544 @@
+//===-------- JITLink_EHFrameSupport.cpp - JITLink eh-frame utils ---------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "EHFrameSupportImpl.h"
+
+#include "llvm/BinaryFormat/Dwarf.h"
+#include "llvm/Support/DynamicLibrary.h"
+
+#define DEBUG_TYPE "jitlink"
+
+namespace llvm {
+namespace jitlink {
+
+EHFrameParser::EHFrameParser(AtomGraph &G, Section &EHFrameSection,
+                             StringRef EHFrameContent,
+                             JITTargetAddress EHFrameAddress,
+                             Edge::Kind FDEToCIERelocKind,
+                             Edge::Kind FDEToTargetRelocKind)
+    : G(G), EHFrameSection(EHFrameSection), EHFrameContent(EHFrameContent),
+      EHFrameAddress(EHFrameAddress),
+      EHFrameReader(EHFrameContent, G.getEndianness()),
+      FDEToCIERelocKind(FDEToCIERelocKind),
+      FDEToTargetRelocKind(FDEToTargetRelocKind) {}
+
+Error EHFrameParser::atomize() {
+  while (!EHFrameReader.empty()) {
+    size_t RecordOffset = EHFrameReader.getOffset();
+
+    LLVM_DEBUG({
+      dbgs() << "Processing eh-frame record at "
+             << format("0x%016" PRIx64, EHFrameAddress + RecordOffset)
+             << " (offset " << RecordOffset << ")\n";
+    });
+
+    size_t CIELength = 0;
+    uint32_t CIELengthField;
+    if (auto Err = EHFrameReader.readInteger(CIELengthField))
+      return Err;
+
+    // Process CIE length/extended-length fields to build the atom.
+    //
+    // The value of these fields describe the length of the *rest* of the CIE
+    // (not including data up to the end of the field itself) so we have to
+    // bump CIELength to include the data up to the end of the field: 4 bytes
+    // for Length, or 12 bytes (4 bytes + 8 bytes) for ExtendedLength.
+    if (CIELengthField == 0) // Length 0 means end of __eh_frame section.
+      break;
+
+    // If the regular length field's value is 0xffffffff, use extended length.
+    if (CIELengthField == 0xffffffff) {
+      uint64_t CIEExtendedLengthField;
+      if (auto Err = EHFrameReader.readInteger(CIEExtendedLengthField))
+        return Err;
+      if (CIEExtendedLengthField > EHFrameReader.bytesRemaining())
+        return make_error<JITLinkError>("CIE record extends past the end of "
+                                        "the __eh_frame section");
+      if (CIEExtendedLengthField + 12 > std::numeric_limits<size_t>::max())
+        return make_error<JITLinkError>("CIE record too large to process");
+      CIELength = CIEExtendedLengthField + 12;
+    } else {
+      if (CIELengthField > EHFrameReader.bytesRemaining())
+        return make_error<JITLinkError>("CIE record extends past the end of "
+                                        "the __eh_frame section");
+      CIELength = CIELengthField + 4;
+    }
+
+    LLVM_DEBUG(dbgs() << "  length: " << CIELength << "\n");
+
+    // Add an atom for this record.
+    CurRecordAtom = &G.addAnonymousAtom(
+        EHFrameSection, EHFrameAddress + RecordOffset, G.getPointerSize());
+    CurRecordAtom->setContent(EHFrameContent.substr(RecordOffset, CIELength));
+
+    // Read the CIE Pointer.
+    size_t CIEPointerAddress = EHFrameAddress + EHFrameReader.getOffset();
+    uint32_t CIEPointer;
+    if (auto Err = EHFrameReader.readInteger(CIEPointer))
+      return Err;
+
+    // Based on the CIE pointer value, parse this as a CIE or FDE record.
+    if (CIEPointer == 0) {
+      if (auto Err = processCIE())
+        return Err;
+    } else {
+      if (auto Err = processFDE(CIEPointerAddress, CIEPointer))
+        return Err;
+    }
+
+    EHFrameReader.setOffset(RecordOffset + CIELength);
+  }
+
+  return Error::success();
+}
+
+Expected<EHFrameParser::AugmentationInfo>
+EHFrameParser::parseAugmentationString() {
+  AugmentationInfo AugInfo;
+  uint8_t NextChar;
+  uint8_t *NextField = &AugInfo.Fields[0];
+
+  if (auto Err = EHFrameReader.readInteger(NextChar))
+    return std::move(Err);
+
+  while (NextChar != 0) {
+    switch (NextChar) {
+    case 'z':
+      AugInfo.AugmentationDataPresent = true;
+      break;
+    case 'e':
+      if (auto Err = EHFrameReader.readInteger(NextChar))
+        return std::move(Err);
+      if (NextChar != 'h')
+        return make_error<JITLinkError>("Unrecognized substring e" +
+                                        Twine(NextChar) +
+                                        " in augmentation string");
+      AugInfo.EHDataFieldPresent = true;
+      break;
+    case 'L':
+    case 'P':
+    case 'R':
+      *NextField++ = NextChar;
+      break;
+    default:
+      return make_error<JITLinkError>("Unrecognized character " +
+                                      Twine(NextChar) +
+                                      " in augmentation string");
+    }
+
+    if (auto Err = EHFrameReader.readInteger(NextChar))
+      return std::move(Err);
+  }
+
+  return std::move(AugInfo);
+}
+
+Expected<JITTargetAddress> EHFrameParser::readAbsolutePointer() {
+  static_assert(sizeof(JITTargetAddress) == sizeof(uint64_t),
+                "Result must be able to hold a uint64_t");
+  JITTargetAddress Addr;
+  if (G.getPointerSize() == 8) {
+    if (auto Err = EHFrameReader.readInteger(Addr))
+      return std::move(Err);
+  } else if (G.getPointerSize() == 4) {
+    uint32_t Addr32;
+    if (auto Err = EHFrameReader.readInteger(Addr32))
+      return std::move(Err);
+    Addr = Addr32;
+  } else
+    llvm_unreachable("Pointer size is not 32-bit or 64-bit");
+  return Addr;
+}
+
+Error EHFrameParser::processCIE() {
+  // Use the dwarf namespace for convenient access to pointer encoding
+  // constants.
+  using namespace dwarf;
+
+  LLVM_DEBUG(dbgs() << "  Record is CIE\n");
+
+  CIEInformation CIEInfo(*CurRecordAtom);
+
+  uint8_t Version = 0;
+  if (auto Err = EHFrameReader.readInteger(Version))
+    return Err;
+
+  if (Version != 0x01)
+    return make_error<JITLinkError>("Bad CIE version " + Twine(Version) +
+                                    " (should be 0x01) in eh-frame");
+
+  auto AugInfo = parseAugmentationString();
+  if (!AugInfo)
+    return AugInfo.takeError();
+
+  // Skip the EH Data field if present.
+  if (AugInfo->EHDataFieldPresent)
+    if (auto Err = EHFrameReader.skip(G.getPointerSize()))
+      return Err;
+
+  // Read and sanity check the code alignment factor.
+  {
+    uint64_t CodeAlignmentFactor = 0;
+    if (auto Err = EHFrameReader.readULEB128(CodeAlignmentFactor))
+      return Err;
+    if (CodeAlignmentFactor != 1)
+      return make_error<JITLinkError>("Unsupported CIE code alignment factor " +
+                                      Twine(CodeAlignmentFactor) +
+                                      " (expected 1)");
+  }
+
+  // Read and sanity check the data alignment factor.
+  {
+    int64_t DataAlignmentFactor = 0;
+    if (auto Err = EHFrameReader.readSLEB128(DataAlignmentFactor))
+      return Err;
+    if (DataAlignmentFactor != -8)
+      return make_error<JITLinkError>("Unsupported CIE data alignment factor " +
+                                      Twine(DataAlignmentFactor) +
+                                      " (expected -8)");
+  }
+
+  // Skip the return address register field.
+  if (auto Err = EHFrameReader.skip(1))
+    return Err;
+
+  uint64_t AugmentationDataLength = 0;
+  if (auto Err = EHFrameReader.readULEB128(AugmentationDataLength))
+    return Err;
+
+  uint32_t AugmentationDataStartOffset = EHFrameReader.getOffset();
+
+  uint8_t *NextField = &AugInfo->Fields[0];
+  while (uint8_t Field = *NextField++) {
+    switch (Field) {
+    case 'L': {
+      CIEInfo.FDEsHaveLSDAField = true;
+      uint8_t LSDAPointerEncoding;
+      if (auto Err = EHFrameReader.readInteger(LSDAPointerEncoding))
+        return Err;
+      if (LSDAPointerEncoding != (DW_EH_PE_pcrel | DW_EH_PE_absptr))
+        return make_error<JITLinkError>(
+            "Unsupported LSDA pointer encoding " +
+            formatv("{0:x2}", LSDAPointerEncoding) + " in CIE at " +
+            formatv("{0:x16}", CurRecordAtom->getAddress()));
+      break;
+    }
+    case 'P': {
+      uint8_t PersonalityPointerEncoding = 0;
+      if (auto Err = EHFrameReader.readInteger(PersonalityPointerEncoding))
+        return Err;
+      if (PersonalityPointerEncoding !=
+          (DW_EH_PE_indirect | DW_EH_PE_pcrel | DW_EH_PE_sdata4))
+        return make_error<JITLinkError>(
+            "Unspported personality pointer "
+            "encoding " +
+            formatv("{0:x2}", PersonalityPointerEncoding) + " in CIE at " +
+            formatv("{0:x16}", CurRecordAtom->getAddress()));
+      uint32_t PersonalityPointerAddress;
+      if (auto Err = EHFrameReader.readInteger(PersonalityPointerAddress))
+        return Err;
+      break;
+    }
+    case 'R': {
+      uint8_t FDEPointerEncoding;
+      if (auto Err = EHFrameReader.readInteger(FDEPointerEncoding))
+        return Err;
+      if (FDEPointerEncoding != (DW_EH_PE_pcrel | DW_EH_PE_absptr))
+        return make_error<JITLinkError>(
+            "Unsupported FDE address pointer "
+            "encoding " +
+            formatv("{0:x2}", FDEPointerEncoding) + " in CIE at " +
+            formatv("{0:x16}", CurRecordAtom->getAddress()));
+      break;
+    }
+    default:
+      llvm_unreachable("Invalid augmentation string field");
+    }
+  }
+
+  if (EHFrameReader.getOffset() - AugmentationDataStartOffset >
+      AugmentationDataLength)
+    return make_error<JITLinkError>("Read past the end of the augmentation "
+                                    "data while parsing fields");
+
+  assert(!CIEInfos.count(CurRecordAtom->getAddress()) &&
+         "Multiple CIEs recorded at the same address?");
+  CIEInfos[CurRecordAtom->getAddress()] = std::move(CIEInfo);
+
+  return Error::success();
+}
+
+Error EHFrameParser::processFDE(JITTargetAddress CIEPointerAddress,
+                                uint32_t CIEPointer) {
+  LLVM_DEBUG(dbgs() << "  Record is FDE\n");
+
+  LLVM_DEBUG({
+    dbgs() << "  CIE pointer: "
+           << format("0x%016" PRIx64, CIEPointerAddress - CIEPointer) << "\n";
+  });
+
+  auto CIEInfoItr = CIEInfos.find(CIEPointerAddress - CIEPointer);
+  if (CIEInfoItr == CIEInfos.end())
+    return make_error<JITLinkError>(
+        "FDE at " + formatv("{0:x16}", CurRecordAtom->getAddress()) +
+        " points to non-existant CIE at " +
+        formatv("{0:x16}", CIEPointerAddress - CIEPointer));
+  auto &CIEInfo = CIEInfoItr->second;
+
+  // The CIEPointer looks good. Add a relocation.
+  CurRecordAtom->addEdge(FDEToCIERelocKind,
+                         CIEPointerAddress - CurRecordAtom->getAddress(),
+                         *CIEInfo.CIEAtom, 0);
+
+  // Read and sanity check the PC-start pointer and size.
+  JITTargetAddress PCBeginAddress = EHFrameAddress + EHFrameReader.getOffset();
+
+  auto PCBeginDelta = readAbsolutePointer();
+  if (!PCBeginDelta)
+    return PCBeginDelta.takeError();
+
+  JITTargetAddress PCBegin = PCBeginAddress + *PCBeginDelta;
+  LLVM_DEBUG({
+    dbgs() << "  PC begin: " << format("0x%016" PRIx64, PCBegin) << "\n";
+  });
+
+  auto *TargetAtom = G.getAtomByAddress(PCBegin);
+
+  if (!TargetAtom)
+    return make_error<JITLinkError>("FDE PC-begin " +
+                                    formatv("{0:x16}", PCBegin) +
+                                    " does not point at atom");
+
+  if (TargetAtom->getAddress() != PCBegin)
+    return make_error<JITLinkError>(
+        "FDE PC-begin " + formatv("{0:x16}", PCBegin) +
+        " does not point to start of atom at " +
+        formatv("{0:x16}", TargetAtom->getAddress()));
+
+  LLVM_DEBUG(dbgs() << "  FDE target: " << *TargetAtom << "\n");
+
+  // The PC-start pointer and size look good. Add relocations.
+  CurRecordAtom->addEdge(FDEToTargetRelocKind,
+                         PCBeginAddress - CurRecordAtom->getAddress(),
+                         *TargetAtom, 0);
+
+  // Add a keep-alive relocation from the function to the FDE to ensure it is
+  // not dead stripped.
+  TargetAtom->addEdge(Edge::KeepAlive, 0, *CurRecordAtom, 0);
+
+  // Skip over the PC range size field.
+  if (auto Err = EHFrameReader.skip(G.getPointerSize()))
+    return Err;
+
+  if (CIEInfo.FDEsHaveLSDAField) {
+    uint64_t AugmentationDataSize;
+    if (auto Err = EHFrameReader.readULEB128(AugmentationDataSize))
+      return Err;
+    if (AugmentationDataSize != G.getPointerSize())
+      return make_error<JITLinkError>(
+          "Unexpected FDE augmentation data size (expected " +
+          Twine(G.getPointerSize()) + ", got " + Twine(AugmentationDataSize) +
+          ") for FDE at " + formatv("{0:x16}", CurRecordAtom->getAddress()));
+    JITTargetAddress LSDAAddress = EHFrameAddress + EHFrameReader.getOffset();
+    auto LSDADelta = readAbsolutePointer();
+    if (!LSDADelta)
+      return LSDADelta.takeError();
+
+    JITTargetAddress LSDA = LSDAAddress + *LSDADelta;
+
+    auto *LSDAAtom = G.getAtomByAddress(LSDA);
+
+    if (!LSDAAtom)
+      return make_error<JITLinkError>("FDE LSDA " + formatv("{0:x16}", LSDA) +
+                                      " does not point at atom");
+
+    if (LSDAAtom->getAddress() != LSDA)
+      return make_error<JITLinkError>(
+          "FDE LSDA " + formatv("{0:x16}", LSDA) +
+          " does not point to start of atom at " +
+          formatv("{0:x16}", LSDAAtom->getAddress()));
+
+    LLVM_DEBUG(dbgs() << "  FDE LSDA: " << *LSDAAtom << "\n");
+
+    // LSDA looks good. Add relocations.
+    CurRecordAtom->addEdge(FDEToTargetRelocKind,
+                           LSDAAddress - CurRecordAtom->getAddress(), *LSDAAtom,
+                           0);
+  }
+
+  return Error::success();
+}
+
+Error addEHFrame(AtomGraph &G, Section &EHFrameSection,
+                 StringRef EHFrameContent, JITTargetAddress EHFrameAddress,
+                 Edge::Kind FDEToCIERelocKind,
+                 Edge::Kind FDEToTargetRelocKind) {
+  return EHFrameParser(G, EHFrameSection, EHFrameContent, EHFrameAddress,
+                       FDEToCIERelocKind, FDEToTargetRelocKind)
+      .atomize();
+}
+
+// Determine whether we can register EH tables.
+#if (defined(__GNUC__) && !defined(__ARM_EABI__) && !defined(__ia64__) &&      \
+     !(defined(_AIX) && defined(__ibmxl__)) && !defined(__SEH__) &&            \
+     !defined(__USING_SJLJ_EXCEPTIONS__))
+#define HAVE_EHTABLE_SUPPORT 1
+#else
+#define HAVE_EHTABLE_SUPPORT 0
+#endif
+
+#if HAVE_EHTABLE_SUPPORT
+extern "C" void __register_frame(const void *);
+extern "C" void __deregister_frame(const void *);
+
+Error registerFrameWrapper(const void *P) {
+  __register_frame(P);
+  return Error::success();
+}
+
+Error deregisterFrameWrapper(const void *P) {
+  __deregister_frame(P);
+  return Error::success();
+}
+
+#else
+
+// The building compiler does not have __(de)register_frame but
+// it may be found at runtime in a dynamically-loaded library.
+// For example, this happens when building LLVM with Visual C++
+// but using the MingW runtime.
+static Error registerFrameWrapper(const void *P) {
+  static void((*RegisterFrame)(const void *)) = 0;
+
+  if (!RegisterFrame)
+    *(void **)&RegisterFrame =
+        llvm::sys::DynamicLibrary::SearchForAddressOfSymbol("__register_frame");
+
+  if (RegisterFrame) {
+    RegisterFrame(P);
+    return Error::success();
+  }
+
+  return make_error<JITLinkError>("could not register eh-frame: "
+                                  "__register_frame function not found");
+}
+
+static Error deregisterFrameWrapper(const void *P) {
+  static void((*DeregisterFrame)(const void *)) = 0;
+
+  if (!DeregisterFrame)
+    *(void **)&DeregisterFrame =
+        llvm::sys::DynamicLibrary::SearchForAddressOfSymbol(
+            "__deregister_frame");
+
+  if (DeregisterFrame) {
+    DeregisterFrame(P);
+    return Error::success();
+  }
+
+  return make_error<JITLinkError>("could not deregister eh-frame: "
+                                  "__deregister_frame function not found");
+}
+#endif
+
+#ifdef __APPLE__
+
+template <typename HandleFDEFn>
+Error walkAppleEHFrameSection(const char *const SectionStart,
+                              HandleFDEFn HandleFDE) {
+  const char *CurCFIRecord = SectionStart;
+  uint64_t Size = *reinterpret_cast<const uint32_t *>(CurCFIRecord);
+
+  while (Size != 0) {
+    const char *OffsetField = CurCFIRecord + (Size == 0xffffffff ? 12 : 4);
+    if (Size == 0xffffffff)
+      Size = *reinterpret_cast<const uint64_t *>(CurCFIRecord + 4) + 12;
+    else
+      Size += 4;
+    uint32_t Offset = *reinterpret_cast<const uint32_t *>(OffsetField);
+    if (Offset != 0)
+      if (auto Err = HandleFDE(CurCFIRecord))
+        return Err;
+
+    LLVM_DEBUG({
+      dbgs() << "Registering eh-frame section:\n";
+      dbgs() << "Processing " << (Offset ? "FDE" : "CIE") << " @"
+             << (void *)CurCFIRecord << ": [";
+      for (unsigned I = 0; I < Size; ++I)
+        dbgs() << format(" 0x%02" PRIx8, *(CurCFIRecord + I));
+      dbgs() << " ]\n";
+    });
+    CurCFIRecord += Size;
+
+    Size = *reinterpret_cast<const uint32_t *>(CurCFIRecord);
+  }
+
+  return Error::success();
+}
+
+#endif // __APPLE__
+
+Error registerEHFrameSection(const void *EHFrameSectionAddr) {
+#ifdef __APPLE__
+  // On Darwin __register_frame has to be called for each FDE entry.
+  return walkAppleEHFrameSection(static_cast<const char *>(EHFrameSectionAddr),
+                                 registerFrameWrapper);
+#else
+  // On Linux __register_frame takes a single argument:
+  // a pointer to the start of the .eh_frame section.
+
+  // How can it find the end? Because crtendS.o is linked
+  // in and it has an .eh_frame section with four zero chars.
+  return registerFrameWrapper(EHFrameSectionAddr);
+#endif
+}
+
+Error deregisterEHFrameSection(const void *EHFrameSectionAddr) {
+#ifdef __APPLE__
+  return walkAppleEHFrameSection(static_cast<const char *>(EHFrameSectionAddr),
+                                 deregisterFrameWrapper);
+#else
+  return deregisterFrameWrapper(EHFrameSectionAddr);
+#endif
+}
+
+EHFrameRegistrar::~EHFrameRegistrar() {}
+
+InProcessEHFrameRegistrar &InProcessEHFrameRegistrar::getInstance() {
+  static InProcessEHFrameRegistrar Instance;
+  return Instance;
+}
+
+InProcessEHFrameRegistrar::InProcessEHFrameRegistrar() {}
+
+AtomGraphPassFunction
+createEHFrameRecorderPass(const Triple &TT,
+                          StoreFrameAddressFunction StoreFrameAddress) {
+  const char *EHFrameSectionName = nullptr;
+  if (TT.getObjectFormat() == Triple::MachO)
+    EHFrameSectionName = "__eh_frame";
+  else
+    EHFrameSectionName = ".eh_frame";
+
+  auto RecordEHFrame = [EHFrameSectionName,
+                        StoreFrameAddress](AtomGraph &G) -> Error {
+    // Search for a non-empty eh-frame and record the address of the first atom
+    // in it.
+    JITTargetAddress Addr = 0;
+    if (auto *S = G.findSectionByName(EHFrameSectionName))
+      Addr = S->getRange().getStart();
+    StoreFrameAddress(Addr);
+    return Error::success();
+  };
+
+  return RecordEHFrame;
+}
+
+} // end namespace jitlink
+} // end namespace llvm