1 files changed, 377 insertions, 0 deletions
diff --git a/lib/DebugInfo/DWARF/DWARFUnit.cpp b/lib/DebugInfo/DWARF/DWARFUnit.cpp
new file mode 100644
index 0000000..d4ecd69
--- /dev/null
+++ b/lib/DebugInfo/DWARF/DWARFUnit.cpp
@@ -0,0 +1,377 @@
+//===-- DWARFUnit.cpp -----------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/DebugInfo/DWARF/DWARFUnit.h"
+#include "llvm/DebugInfo/DWARF/DWARFContext.h"
+#include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
+#include "llvm/Support/Dwarf.h"
+#include "llvm/Support/Path.h"
+#include <cstdio>
+
+using namespace llvm;
+using namespace dwarf;
+
+void DWARFUnitSectionBase::parse(DWARFContext &C, const DWARFSection &Section) {
+  parseImpl(C, Section, C.getDebugAbbrev(), C.getRangeSection(),
+            C.getStringSection(), StringRef(), C.getAddrSection(),
+            C.isLittleEndian());
+}
+
+void DWARFUnitSectionBase::parseDWO(DWARFContext &C,
+                                    const DWARFSection &DWOSection) {
+  parseImpl(C, DWOSection, C.getDebugAbbrevDWO(), C.getRangeDWOSection(),
+            C.getStringDWOSection(), C.getStringOffsetDWOSection(),
+            C.getAddrSection(), C.isLittleEndian());
+}
+
+DWARFUnit::DWARFUnit(DWARFContext &DC, const DWARFSection &Section,
+                     const DWARFDebugAbbrev *DA, StringRef RS, StringRef SS,
+                     StringRef SOS, StringRef AOS, bool LE,
+                     const DWARFUnitSectionBase &UnitSection)
+    : Context(DC), InfoSection(Section), Abbrev(DA), RangeSection(RS),
+      StringSection(SS), StringOffsetSection(SOS), AddrOffsetSection(AOS),
+      isLittleEndian(LE), UnitSection(UnitSection) {
+  clear();
+}
+
+DWARFUnit::~DWARFUnit() {
+}
+
+bool DWARFUnit::getAddrOffsetSectionItem(uint32_t Index,
+                                                uint64_t &Result) const {
+  uint32_t Offset = AddrOffsetSectionBase + Index * AddrSize;
+  if (AddrOffsetSection.size() < Offset + AddrSize)
+    return false;
+  DataExtractor DA(AddrOffsetSection, isLittleEndian, AddrSize);
+  Result = DA.getAddress(&Offset);
+  return true;
+}
+
+bool DWARFUnit::getStringOffsetSectionItem(uint32_t Index,
+                                                  uint32_t &Result) const {
+  // FIXME: string offset section entries are 8-byte for DWARF64.
+  const uint32_t ItemSize = 4;
+  uint32_t Offset = Index * ItemSize;
+  if (StringOffsetSection.size() < Offset + ItemSize)
+    return false;
+  DataExtractor DA(StringOffsetSection, isLittleEndian, 0);
+  Result = DA.getU32(&Offset);
+  return true;
+}
+
+bool DWARFUnit::extractImpl(DataExtractor debug_info, uint32_t *offset_ptr) {
+  Length = debug_info.getU32(offset_ptr);
+  Version = debug_info.getU16(offset_ptr);
+  uint64_t AbbrOffset = debug_info.getU32(offset_ptr);
+  AddrSize = debug_info.getU8(offset_ptr);
+
+  bool LengthOK = debug_info.isValidOffset(getNextUnitOffset() - 1);
+  bool VersionOK = DWARFContext::isSupportedVersion(Version);
+  bool AddrSizeOK = AddrSize == 4 || AddrSize == 8;
+
+  if (!LengthOK || !VersionOK || !AddrSizeOK)
+    return false;
+
+  Abbrevs = Abbrev->getAbbreviationDeclarationSet(AbbrOffset);
+  if (Abbrevs == nullptr)
+    return false;
+
+  return true;
+}
+
+bool DWARFUnit::extract(DataExtractor debug_info, uint32_t *offset_ptr) {
+  clear();
+
+  Offset = *offset_ptr;
+
+  if (debug_info.isValidOffset(*offset_ptr)) {
+    if (extractImpl(debug_info, offset_ptr))
+      return true;
+
+    // reset the offset to where we tried to parse from if anything went wrong
+    *offset_ptr = Offset;
+  }
+
+  return false;
+}
+
+bool DWARFUnit::extractRangeList(uint32_t RangeListOffset,
+                                        DWARFDebugRangeList &RangeList) const {
+  // Require that compile unit is extracted.
+  assert(DieArray.size() > 0);
+  DataExtractor RangesData(RangeSection, isLittleEndian, AddrSize);
+  uint32_t ActualRangeListOffset = RangeSectionBase + RangeListOffset;
+  return RangeList.extract(RangesData, &ActualRangeListOffset);
+}
+
+void DWARFUnit::clear() {
+  Offset = 0;
+  Length = 0;
+  Version = 0;
+  Abbrevs = nullptr;
+  AddrSize = 0;
+  BaseAddr = 0;
+  RangeSectionBase = 0;
+  AddrOffsetSectionBase = 0;
+  clearDIEs(false);
+  DWO.reset();
+}
+
+const char *DWARFUnit::getCompilationDir() {
+  extractDIEsIfNeeded(true);
+  if (DieArray.empty())
+    return nullptr;
+  return DieArray[0].getAttributeValueAsString(this, DW_AT_comp_dir, nullptr);
+}
+
+uint64_t DWARFUnit::getDWOId() {
+  extractDIEsIfNeeded(true);
+  const uint64_t FailValue = -1ULL;
+  if (DieArray.empty())
+    return FailValue;
+  return DieArray[0]
+      .getAttributeValueAsUnsignedConstant(this, DW_AT_GNU_dwo_id, FailValue);
+}
+
+void DWARFUnit::setDIERelations() {
+  if (DieArray.size() <= 1)
+    return;
+
+  std::vector<DWARFDebugInfoEntryMinimal *> ParentChain;
+  DWARFDebugInfoEntryMinimal *SiblingChain = nullptr;
+  for (auto &DIE : DieArray) {
+    if (SiblingChain) {
+      SiblingChain->setSibling(&DIE);
+    }
+    if (const DWARFAbbreviationDeclaration *AbbrDecl =
+            DIE.getAbbreviationDeclarationPtr()) {
+      // Normal DIE.
+      if (AbbrDecl->hasChildren()) {
+        ParentChain.push_back(&DIE);
+        SiblingChain = nullptr;
+      } else {
+        SiblingChain = &DIE;
+      }
+    } else {
+      // NULL entry terminates the sibling chain.
+      SiblingChain = ParentChain.back();
+      ParentChain.pop_back();
+    }
+  }
+  assert(SiblingChain == nullptr || SiblingChain == &DieArray[0]);
+  assert(ParentChain.empty());
+}
+
+void DWARFUnit::extractDIEsToVector(
+    bool AppendCUDie, bool AppendNonCUDies,
+    std::vector<DWARFDebugInfoEntryMinimal> &Dies) const {
+  if (!AppendCUDie && !AppendNonCUDies)
+    return;
+
+  // Set the offset to that of the first DIE and calculate the start of the
+  // next compilation unit header.
+  uint32_t DIEOffset = Offset + getHeaderSize();
+  uint32_t NextCUOffset = getNextUnitOffset();
+  DWARFDebugInfoEntryMinimal DIE;
+  uint32_t Depth = 0;
+  bool IsCUDie = true;
+
+  while (DIEOffset < NextCUOffset && DIE.extractFast(this, &DIEOffset)) {
+    if (IsCUDie) {
+      if (AppendCUDie)
+        Dies.push_back(DIE);
+      if (!AppendNonCUDies)
+        break;
+      // The average bytes per DIE entry has been seen to be
+      // around 14-20 so let's pre-reserve the needed memory for
+      // our DIE entries accordingly.
+      Dies.reserve(Dies.size() + getDebugInfoSize() / 14);
+      IsCUDie = false;
+    } else {
+      Dies.push_back(DIE);
+    }
+
+    if (const DWARFAbbreviationDeclaration *AbbrDecl =
+            DIE.getAbbreviationDeclarationPtr()) {
+      // Normal DIE
+      if (AbbrDecl->hasChildren())
+        ++Depth;
+    } else {
+      // NULL DIE.
+      if (Depth > 0)
+        --Depth;
+      if (Depth == 0)
+        break;  // We are done with this compile unit!
+    }
+  }
+
+  // Give a little bit of info if we encounter corrupt DWARF (our offset
+  // should always terminate at or before the start of the next compilation
+  // unit header).
+  if (DIEOffset > NextCUOffset)
+    fprintf(stderr, "warning: DWARF compile unit extends beyond its "
+                    "bounds cu 0x%8.8x at 0x%8.8x'\n", getOffset(), DIEOffset);
+}
+
+size_t DWARFUnit::extractDIEsIfNeeded(bool CUDieOnly) {
+  if ((CUDieOnly && DieArray.size() > 0) ||
+      DieArray.size() > 1)
+    return 0; // Already parsed.
+
+  bool HasCUDie = DieArray.size() > 0;
+  extractDIEsToVector(!HasCUDie, !CUDieOnly, DieArray);
+
+  if (DieArray.empty())
+    return 0;
+
+  // If CU DIE was just parsed, copy several attribute values from it.
+  if (!HasCUDie) {
+    uint64_t BaseAddr =
+        DieArray[0].getAttributeValueAsAddress(this, DW_AT_low_pc, -1ULL);
+    if (BaseAddr == -1ULL)
+      BaseAddr = DieArray[0].getAttributeValueAsAddress(this, DW_AT_entry_pc, 0);
+    setBaseAddress(BaseAddr);
+    AddrOffsetSectionBase = DieArray[0].getAttributeValueAsSectionOffset(
+        this, DW_AT_GNU_addr_base, 0);
+    RangeSectionBase = DieArray[0].getAttributeValueAsSectionOffset(
+        this, DW_AT_ranges_base, 0);
+    // Don't fall back to DW_AT_GNU_ranges_base: it should be ignored for
+    // skeleton CU DIE, so that DWARF users not aware of it are not broken.
+  }
+
+  setDIERelations();
+  return DieArray.size();
+}
+
+DWARFUnit::DWOHolder::DWOHolder(StringRef DWOPath)
+    : DWOFile(), DWOContext(), DWOU(nullptr) {
+  auto Obj = object::ObjectFile::createObjectFile(DWOPath);
+  if (!Obj)
+    return;
+  DWOFile = std::move(Obj.get());
+  DWOContext.reset(
+      cast<DWARFContext>(DIContext::getDWARFContext(*DWOFile.getBinary())));
+  if (DWOContext->getNumDWOCompileUnits() > 0)
+    DWOU = DWOContext->getDWOCompileUnitAtIndex(0);
+}
+
+bool DWARFUnit::parseDWO() {
+  if (DWO.get())
+    return false;
+  extractDIEsIfNeeded(true);
+  if (DieArray.empty())
+    return false;
+  const char *DWOFileName =
+      DieArray[0].getAttributeValueAsString(this, DW_AT_GNU_dwo_name, nullptr);
+  if (!DWOFileName)
+    return false;
+  const char *CompilationDir =
+      DieArray[0].getAttributeValueAsString(this, DW_AT_comp_dir, nullptr);
+  SmallString<16> AbsolutePath;
+  if (sys::path::is_relative(DWOFileName) && CompilationDir != nullptr) {
+    sys::path::append(AbsolutePath, CompilationDir);
+  }
+  sys::path::append(AbsolutePath, DWOFileName);
+  DWO = llvm::make_unique<DWOHolder>(AbsolutePath);
+  DWARFUnit *DWOCU = DWO->getUnit();
+  // Verify that compile unit in .dwo file is valid.
+  if (!DWOCU || DWOCU->getDWOId() != getDWOId()) {
+    DWO.reset();
+    return false;
+  }
+  // Share .debug_addr and .debug_ranges section with compile unit in .dwo
+  DWOCU->setAddrOffsetSection(AddrOffsetSection, AddrOffsetSectionBase);
+  uint32_t DWORangesBase = DieArray[0].getRangesBaseAttribute(this, 0);
+  DWOCU->setRangesSection(RangeSection, DWORangesBase);
+  return true;
+}
+
+void DWARFUnit::clearDIEs(bool KeepCUDie) {
+  if (DieArray.size() > (unsigned)KeepCUDie) {
+    // std::vectors never get any smaller when resized to a smaller size,
+    // or when clear() or erase() are called, the size will report that it
+    // is smaller, but the memory allocated remains intact (call capacity()
+    // to see this). So we need to create a temporary vector and swap the
+    // contents which will cause just the internal pointers to be swapped
+    // so that when temporary vector goes out of scope, it will destroy the
+    // contents.
+    std::vector<DWARFDebugInfoEntryMinimal> TmpArray;
+    DieArray.swap(TmpArray);
+    // Save at least the compile unit DIE
+    if (KeepCUDie)
+      DieArray.push_back(TmpArray.front());
+  }
+}
+
+void DWARFUnit::collectAddressRanges(DWARFAddressRangesVector &CURanges) {
+  // First, check if CU DIE describes address ranges for the unit.
+  const auto &CUDIERanges = getCompileUnitDIE()->getAddressRanges(this);
+  if (!CUDIERanges.empty()) {
+    CURanges.insert(CURanges.end(), CUDIERanges.begin(), CUDIERanges.end());
+    return;
+  }
+
+  // This function is usually called if there in no .debug_aranges section
+  // in order to produce a compile unit level set of address ranges that
+  // is accurate. If the DIEs weren't parsed, then we don't want all dies for
+  // all compile units to stay loaded when they weren't needed. So we can end
+  // up parsing the DWARF and then throwing them all away to keep memory usage
+  // down.
+  const bool ClearDIEs = extractDIEsIfNeeded(false) > 1;
+  DieArray[0].collectChildrenAddressRanges(this, CURanges);
+
+  // Collect address ranges from DIEs in .dwo if necessary.
+  bool DWOCreated = parseDWO();
+  if (DWO.get())
+    DWO->getUnit()->collectAddressRanges(CURanges);
+  if (DWOCreated)
+    DWO.reset();
+
+  // Keep memory down by clearing DIEs if this generate function
+  // caused them to be parsed.
+  if (ClearDIEs)
+    clearDIEs(true);
+}
+
+const DWARFDebugInfoEntryMinimal *
+DWARFUnit::getSubprogramForAddress(uint64_t Address) {
+  extractDIEsIfNeeded(false);
+  for (const DWARFDebugInfoEntryMinimal &DIE : DieArray) {
+    if (DIE.isSubprogramDIE() &&
+        DIE.addressRangeContainsAddress(this, Address)) {
+      return &DIE;
+    }
+  }
+  return nullptr;
+}
+
+DWARFDebugInfoEntryInlinedChain
+DWARFUnit::getInlinedChainForAddress(uint64_t Address) {
+  // First, find a subprogram that contains the given address (the root
+  // of inlined chain).
+  const DWARFUnit *ChainCU = nullptr;
+  const DWARFDebugInfoEntryMinimal *SubprogramDIE =
+      getSubprogramForAddress(Address);
+  if (SubprogramDIE) {
+    ChainCU = this;
+  } else {
+    // Try to look for subprogram DIEs in the DWO file.
+    parseDWO();
+    if (DWO.get()) {
+      SubprogramDIE = DWO->getUnit()->getSubprogramForAddress(Address);
+      if (SubprogramDIE)
+        ChainCU = DWO->getUnit();
+    }
+  }
+
+  // Get inlined chain rooted at this subprogram DIE.
+  if (!SubprogramDIE)
+    return DWARFDebugInfoEntryInlinedChain();
+  return SubprogramDIE->getInlinedChainForAddress(ChainCU, Address);
+}