1 files changed, 391 insertions, 0 deletions
diff --git a/lib/DebugInfo/DWARFUnit.cpp b/lib/DebugInfo/DWARFUnit.cpp
new file mode 100644
index 0000000..c5ffb33
--- /dev/null
+++ b/lib/DebugInfo/DWARFUnit.cpp
@@ -0,0 +1,391 @@
+//===-- DWARFUnit.cpp -----------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "DWARFUnit.h"
+#include "DWARFContext.h"
+#include "llvm/DebugInfo/DWARFFormValue.h"
+#include "llvm/Support/Dwarf.h"
+#include "llvm/Support/Path.h"
+
+using namespace llvm;
+using namespace dwarf;
+
+DWARFUnit::DWARFUnit(const DWARFDebugAbbrev *DA, StringRef IS, StringRef AS,
+                     StringRef RS, StringRef SS, StringRef SOS, StringRef AOS,
+                     const RelocAddrMap *M, bool LE)
+    : Abbrev(DA), InfoSection(IS), AbbrevSection(AS), RangeSection(RS),
+      StringSection(SS), StringOffsetSection(SOS), AddrOffsetSection(AOS),
+      RelocMap(M), isLittleEndian(LE) {
+  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 abbrOffsetOK = AbbrevSection.size() > abbrOffset;
+  bool addrSizeOK = AddrSize == 4 || AddrSize == 8;
+
+  if (!lengthOK || !versionOK || !addrSizeOK || !abbrOffsetOK)
+    return false;
+
+  Abbrevs = Abbrev->getAbbreviationDeclarationSet(abbrOffset);
+  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;
+}
+
+uint32_t
+DWARFUnit::extract(uint32_t offset, DataExtractor debug_info_data,
+                          const DWARFAbbreviationDeclarationSet *abbrevs) {
+  clear();
+
+  Offset = offset;
+
+  if (debug_info_data.isValidOffset(offset)) {
+    Length = debug_info_data.getU32(&offset);
+    Version = debug_info_data.getU16(&offset);
+    bool abbrevsOK = debug_info_data.getU32(&offset) == abbrevs->getOffset();
+    Abbrevs = abbrevs;
+    AddrSize = debug_info_data.getU8(&offset);
+
+    bool versionOK = DWARFContext::isSupportedVersion(Version);
+    bool addrSizeOK = AddrSize == 4 || AddrSize == 8;
+
+    if (versionOK && addrSizeOK && abbrevsOK &&
+        debug_info_data.isValidOffset(offset))
+      return offset;
+  }
+  return 0;
+}
+
+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 = 0;
+  AddrSize = 0;
+  BaseAddr = 0;
+  RangeSectionBase = 0;
+  AddrOffsetSectionBase = 0;
+  clearDIEs(false);
+  DWO.reset();
+}
+
+const char *DWARFUnit::getCompilationDir() {
+  extractDIEsIfNeeded(true);
+  if (DieArray.empty())
+    return 0;
+  return DieArray[0].getAttributeValueAsString(this, DW_AT_comp_dir, 0);
+}
+
+uint64_t DWARFUnit::getDWOId() {
+  extractDIEsIfNeeded(true);
+  const uint64_t FailValue = -1ULL;
+  if (DieArray.empty())
+    return FailValue;
+  return DieArray[0]
+      .getAttributeValueAsUnsigned(this, DW_AT_GNU_dwo_id, FailValue);
+}
+
+void DWARFUnit::setDIERelations() {
+  if (DieArray.empty())
+    return;
+  DWARFDebugInfoEntryMinimal *die_array_begin = &DieArray.front();
+  DWARFDebugInfoEntryMinimal *die_array_end = &DieArray.back();
+  DWARFDebugInfoEntryMinimal *curr_die;
+  // We purposely are skipping the last element in the array in the loop below
+  // so that we can always have a valid next item
+  for (curr_die = die_array_begin; curr_die < die_array_end; ++curr_die) {
+    // Since our loop doesn't include the last element, we can always
+    // safely access the next die in the array.
+    DWARFDebugInfoEntryMinimal *next_die = curr_die + 1;
+
+    const DWARFAbbreviationDeclaration *curr_die_abbrev =
+      curr_die->getAbbreviationDeclarationPtr();
+
+    if (curr_die_abbrev) {
+      // Normal DIE
+      if (curr_die_abbrev->hasChildren())
+        next_die->setParent(curr_die);
+      else
+        curr_die->setSibling(next_die);
+    } else {
+      // NULL DIE that terminates a sibling chain
+      DWARFDebugInfoEntryMinimal *parent = curr_die->getParent();
+      if (parent)
+        parent->setSibling(next_die);
+    }
+  }
+
+  // Since we skipped the last element, we need to fix it up!
+  if (die_array_begin < die_array_end)
+    curr_die->setParent(die_array_begin);
+}
+
+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 Offset = getFirstDIEOffset();
+  uint32_t NextCUOffset = getNextUnitOffset();
+  DWARFDebugInfoEntryMinimal DIE;
+  uint32_t Depth = 0;
+  const uint8_t *FixedFormSizes =
+    DWARFFormValue::getFixedFormSizes(getAddressByteSize(), getVersion());
+  bool IsCUDie = true;
+
+  while (Offset < NextCUOffset &&
+         DIE.extractFast(this, FixedFormSizes, &Offset)) {
+    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);
+    }
+
+    const DWARFAbbreviationDeclaration *AbbrDecl =
+      DIE.getAbbreviationDeclarationPtr();
+    if (AbbrDecl) {
+      // 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 (Offset > NextCUOffset)
+    fprintf(stderr, "warning: DWARF compile unit extends beyond its "
+                    "bounds cu 0x%8.8x at 0x%8.8x'\n", getOffset(), Offset);
+}
+
+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].getAttributeValueAsUnsigned(this, DW_AT_low_pc, -1U);
+    if (BaseAddr == -1U)
+      BaseAddr = DieArray[0].getAttributeValueAsUnsigned(this, DW_AT_entry_pc, 0);
+    setBaseAddress(BaseAddr);
+    AddrOffsetSectionBase =
+        DieArray[0].getAttributeValueAsReference(this, DW_AT_GNU_addr_base, 0);
+    RangeSectionBase =
+        DieArray[0].getAttributeValueAsReference(this, DW_AT_GNU_ranges_base, 0);
+  }
+
+  setDIERelations();
+  return DieArray.size();
+}
+
+DWARFUnit::DWOHolder::DWOHolder(object::ObjectFile *DWOFile)
+    : DWOFile(DWOFile),
+      DWOContext(cast<DWARFContext>(DIContext::getDWARFContext(DWOFile))),
+      DWOU(0) {
+  if (DWOContext->getNumDWOCompileUnits() > 0)
+    DWOU = DWOContext->getDWOCompileUnitAtIndex(0);
+}
+
+bool DWARFUnit::parseDWO() {
+  if (DWO.get() != 0)
+    return false;
+  extractDIEsIfNeeded(true);
+  if (DieArray.empty())
+    return false;
+  const char *DWOFileName =
+      DieArray[0].getAttributeValueAsString(this, DW_AT_GNU_dwo_name, 0);
+  if (DWOFileName == 0)
+    return false;
+  const char *CompilationDir =
+      DieArray[0].getAttributeValueAsString(this, DW_AT_comp_dir, 0);
+  SmallString<16> AbsolutePath;
+  if (sys::path::is_relative(DWOFileName) && CompilationDir != 0) {
+    sys::path::append(AbsolutePath, CompilationDir);
+  }
+  sys::path::append(AbsolutePath, DWOFileName);
+  object::ObjectFile *DWOFile =
+      object::ObjectFile::createObjectFile(AbsolutePath);
+  if (!DWOFile)
+    return false;
+  // Reset DWOHolder.
+  DWO.reset(new DWOHolder(DWOFile));
+  DWARFUnit *DWOCU = DWO->getUnit();
+  // Verify that compile unit in .dwo file is valid.
+  if (DWOCU == 0 || DWOCU->getDWOId() != getDWOId()) {
+    DWO.reset();
+    return false;
+  }
+  // Share .debug_addr and .debug_ranges section with compile unit in .dwo
+  DWOCU->setAddrOffsetSection(AddrOffsetSection, AddrOffsetSectionBase);
+  DWOCU->setRangesSection(RangeSection, RangeSectionBase);
+  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::buildAddressRangeTable(DWARFDebugAranges *debug_aranges,
+                                         bool clear_dies_if_already_not_parsed,
+                                         uint32_t CUOffsetInAranges) {
+  // 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 clear_dies = extractDIEsIfNeeded(false) > 1 &&
+                          clear_dies_if_already_not_parsed;
+  DieArray[0].buildAddressRangeTable(this, debug_aranges, CUOffsetInAranges);
+  bool DWOCreated = parseDWO();
+  if (DWO.get()) {
+    // If there is a .dwo file for this compile unit, then skeleton CU DIE
+    // doesn't have children, and we should instead build address range table
+    // from DIEs in the .debug_info.dwo section of .dwo file.
+    DWO->getUnit()->buildAddressRangeTable(
+        debug_aranges, clear_dies_if_already_not_parsed, CUOffsetInAranges);
+  }
+  if (DWOCreated && clear_dies_if_already_not_parsed)
+    DWO.reset();
+
+  // Keep memory down by clearing DIEs if this generate function
+  // caused them to be parsed.
+  if (clear_dies)
+    clearDIEs(true);
+}
+
+const DWARFDebugInfoEntryMinimal *
+DWARFUnit::getSubprogramForAddress(uint64_t Address) {
+  extractDIEsIfNeeded(false);
+  for (size_t i = 0, n = DieArray.size(); i != n; i++)
+    if (DieArray[i].isSubprogramDIE() &&
+        DieArray[i].addressRangeContainsAddress(this, Address)) {
+      return &DieArray[i];
+    }
+  return 0;
+}
+
+DWARFDebugInfoEntryInlinedChain
+DWARFUnit::getInlinedChainForAddress(uint64_t Address) {
+  // First, find a subprogram that contains the given address (the root
+  // of inlined chain).
+  const DWARFUnit *ChainCU = 0;
+  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);
+}