Coverage Report

Created: 2017-09-19 22:28

/Users/buildslave/jenkins/sharedspace/clang-stage2-coverage-R@2/llvm/tools/lld/lib/ReaderWriter/MachO/CompactUnwindPass.cpp
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//===- lib/ReaderWriter/MachO/CompactUnwindPass.cpp -------------*- C++ -*-===//
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//
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//                             The LLVM Linker
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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///
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/// \file A pass to convert MachO's __compact_unwind sections into the final
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/// __unwind_info format used during runtime. See
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/// mach-o/compact_unwind_encoding.h for more details on the formats involved.
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///
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//===----------------------------------------------------------------------===//
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#include "ArchHandler.h"
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#include "File.h"
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#include "MachONormalizedFileBinaryUtils.h"
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#include "MachOPasses.h"
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#include "lld/Core/DefinedAtom.h"
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#include "lld/Core/File.h"
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#include "lld/Core/LLVM.h"
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#include "lld/Core/Reference.h"
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#include "lld/Core/Simple.h"
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/Format.h"
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#define DEBUG_TYPE "macho-compact-unwind"
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namespace lld {
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namespace mach_o {
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namespace {
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struct CompactUnwindEntry {
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  const Atom *rangeStart;
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  const Atom *personalityFunction;
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  const Atom *lsdaLocation;
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  const Atom *ehFrame;
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  uint32_t rangeLength;
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  // There are 3 types of compact unwind entry, distinguished by the encoding
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  // value: 0 indicates a function with no unwind info;
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  // _archHandler.dwarfCompactUnwindType() indicates that the entry defers to
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  // __eh_frame, and that the ehFrame entry will be valid; any other value is a
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  // real compact unwind entry -- personalityFunction will be set and
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  // lsdaLocation may be.
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  uint32_t encoding;
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  CompactUnwindEntry(const DefinedAtom *function)
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      : rangeStart(function), personalityFunction(nullptr),
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        lsdaLocation(nullptr), ehFrame(nullptr), rangeLength(function->size()),
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0
        encoding(0) {}
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56
  CompactUnwindEntry()
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      : rangeStart(nullptr), personalityFunction(nullptr),
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40
        lsdaLocation(nullptr), ehFrame(nullptr), rangeLength(0), encoding(0) {}
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};
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61
struct UnwindInfoPage {
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  ArrayRef<CompactUnwindEntry> entries;
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};
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}
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66
class UnwindInfoAtom : public SimpleDefinedAtom {
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public:
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  UnwindInfoAtom(ArchHandler &archHandler, const File &file, bool isBig,
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                 std::vector<const Atom *> &personalities,
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                 std::vector<uint32_t> &commonEncodings,
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                 std::vector<UnwindInfoPage> &pages, uint32_t numLSDAs)
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      : SimpleDefinedAtom(file), _archHandler(archHandler),
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        _commonEncodingsOffset(7 * sizeof(uint32_t)),
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        _personalityArrayOffset(_commonEncodingsOffset +
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                                commonEncodings.size() * sizeof(uint32_t)),
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        _topLevelIndexOffset(_personalityArrayOffset +
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                             personalities.size() * sizeof(uint32_t)),
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        _lsdaIndexOffset(_topLevelIndexOffset +
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                         3 * (pages.size() + 1) * sizeof(uint32_t)),
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        _firstPageOffset(_lsdaIndexOffset + 2 * numLSDAs * sizeof(uint32_t)),
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10
        _isBig(isBig) {
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10
83
10
    addHeader(commonEncodings.size(), personalities.size(), pages.size());
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10
    addCommonEncodings(commonEncodings);
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10
    addPersonalityFunctions(personalities);
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10
    addTopLevelIndexes(pages);
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10
    addLSDAIndexes(pages, numLSDAs);
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10
    addSecondLevelPages(pages);
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10
  }
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  ~UnwindInfoAtom() override = default;
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93
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  ContentType contentType() const override {
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    return DefinedAtom::typeProcessedUnwindInfo;
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79
  }
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97
10
  Alignment alignment() const override { return 4; }
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30
  uint64_t size() const override { return _contents.size(); }
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0
  ContentPermissions permissions() const override {
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0
    return DefinedAtom::permR__;
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0
  }
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20
  ArrayRef<uint8_t> rawContent() const override { return _contents; }
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  void addHeader(uint32_t numCommon, uint32_t numPersonalities,
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10
                 uint32_t numPages) {
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10
    using normalized::write32;
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10
111
10
    uint32_t headerSize = 7 * sizeof(uint32_t);
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10
    _contents.resize(headerSize);
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10
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10
    uint8_t *headerEntries = _contents.data();
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    // version
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10
    write32(headerEntries, 1, _isBig);
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    // commonEncodingsArraySectionOffset
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10
    write32(headerEntries + sizeof(uint32_t), _commonEncodingsOffset, _isBig);
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    // commonEncodingsArrayCount
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10
    write32(headerEntries + 2 * sizeof(uint32_t), numCommon, _isBig);
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    // personalityArraySectionOffset
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    write32(headerEntries + 3 * sizeof(uint32_t), _personalityArrayOffset,
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            _isBig);
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    // personalityArrayCount
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10
    write32(headerEntries + 4 * sizeof(uint32_t), numPersonalities, _isBig);
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10
    // indexSectionOffset
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10
    write32(headerEntries + 5 * sizeof(uint32_t), _topLevelIndexOffset, _isBig);
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    // indexCount
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    write32(headerEntries + 6 * sizeof(uint32_t), numPages + 1, _isBig);
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10
  }
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  /// Add the list of common encodings to the section; this is simply an array
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  /// of uint32_t compact values. Size has already been specified in the header.
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  void addCommonEncodings(std::vector<uint32_t> &commonEncodings) {
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10
    using normalized::write32;
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    _contents.resize(_commonEncodingsOffset +
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10
                     commonEncodings.size() * sizeof(uint32_t));
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10
    uint8_t *commonEncodingsArea =
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        reinterpret_cast<uint8_t *>(_contents.data() + _commonEncodingsOffset);
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10
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0
    for (uint32_t encoding : commonEncodings) {
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0
      write32(commonEncodingsArea, encoding, _isBig);
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0
      commonEncodingsArea += sizeof(uint32_t);
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0
    }
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  }
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  void addPersonalityFunctions(std::vector<const Atom *> personalities) {
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10
    _contents.resize(_personalityArrayOffset +
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10
                     personalities.size() * sizeof(uint32_t));
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10
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12
    for (unsigned i = 0; 
i < personalities.size()12
;
++i2
)
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2
      addImageReferenceIndirect(_personalityArrayOffset + i * sizeof(uint32_t),
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2
                                personalities[i]);
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10
  }
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10
  void addTopLevelIndexes(std::vector<UnwindInfoPage> &pages) {
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10
    using normalized::write32;
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10
160
10
    uint32_t numIndexes = pages.size() + 1;
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    _contents.resize(_topLevelIndexOffset + numIndexes * 3 * sizeof(uint32_t));
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10
    uint32_t pageLoc = _firstPageOffset;
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10
165
10
    // The most difficult job here is calculating the LSDAs; everything else
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10
    // follows fairly naturally, but we can't state where the first
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10
    uint8_t *indexData = &_contents[_topLevelIndexOffset];
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10
    uint32_t numLSDAs = 0;
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20
    for (unsigned i = 0; 
i < pages.size()20
;
++i10
) {
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10
      // functionOffset
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10
      addImageReference(_topLevelIndexOffset + 3 * i * sizeof(uint32_t),
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10
                        pages[i].entries[0].rangeStart);
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10
      // secondLevelPagesSectionOffset
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10
      write32(indexData + (3 * i + 1) * sizeof(uint32_t), pageLoc, _isBig);
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10
      write32(indexData + (3 * i + 2) * sizeof(uint32_t),
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10
              _lsdaIndexOffset + numLSDAs * 2 * sizeof(uint32_t), _isBig);
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10
178
10
      for (auto &entry : pages[i].entries)
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25
        
if (25
entry.lsdaLocation25
)
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2
          ++numLSDAs;
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10
    }
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10
183
10
    // Finally, write out the final sentinel index
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10
    auto &finalEntry = pages[pages.size() - 1].entries.back();
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10
    addImageReference(_topLevelIndexOffset +
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10
                          3 * pages.size() * sizeof(uint32_t),
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10
                      finalEntry.rangeStart, finalEntry.rangeLength);
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10
    // secondLevelPagesSectionOffset => 0
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10
    write32(indexData + (3 * pages.size() + 2) * sizeof(uint32_t),
190
10
            _lsdaIndexOffset + numLSDAs * 2 * sizeof(uint32_t), _isBig);
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10
  }
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193
10
  void addLSDAIndexes(std::vector<UnwindInfoPage> &pages, uint32_t numLSDAs) {
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10
    _contents.resize(_lsdaIndexOffset + numLSDAs * 2 * sizeof(uint32_t));
195
10
196
10
    uint32_t curOffset = _lsdaIndexOffset;
197
10
    for (auto &page : pages) {
198
25
      for (auto &entry : page.entries) {
199
25
        if (!entry.lsdaLocation)
200
23
          continue;
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2
202
2
        addImageReference(curOffset, entry.rangeStart);
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2
        addImageReference(curOffset + sizeof(uint32_t), entry.lsdaLocation);
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2
        curOffset += 2 * sizeof(uint32_t);
205
2
      }
206
10
    }
207
10
  }
208
209
10
  void addSecondLevelPages(std::vector<UnwindInfoPage> &pages) {
210
10
    for (auto &page : pages) {
211
10
      addRegularSecondLevelPage(page);
212
10
    }
213
10
  }
214
215
10
  void addRegularSecondLevelPage(const UnwindInfoPage &page) {
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10
    uint32_t curPageOffset = _contents.size();
217
10
    const int16_t headerSize = sizeof(uint32_t) + 2 * sizeof(uint16_t);
218
10
    uint32_t curPageSize =
219
10
        headerSize + 2 * page.entries.size() * sizeof(uint32_t);
220
10
    _contents.resize(curPageOffset + curPageSize);
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10
222
10
    using normalized::write32;
223
10
    using normalized::write16;
224
10
    // 2 => regular page
225
10
    write32(&_contents[curPageOffset], 2, _isBig);
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10
    // offset of 1st entry
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10
    write16(&_contents[curPageOffset + 4], headerSize, _isBig);
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10
    write16(&_contents[curPageOffset + 6], page.entries.size(), _isBig);
229
10
230
10
    uint32_t pagePos = curPageOffset + headerSize;
231
25
    for (auto &entry : page.entries) {
232
25
      addImageReference(pagePos, entry.rangeStart);
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25
234
25
      write32(_contents.data() + pagePos + sizeof(uint32_t), entry.encoding,
235
25
              _isBig);
236
25
      if ((entry.encoding & 0x0f000000U) ==
237
25
          _archHandler.dwarfCompactUnwindType())
238
3
        addEhFrameReference(pagePos + sizeof(uint32_t), entry.ehFrame);
239
25
240
25
      pagePos += 2 * sizeof(uint32_t);
241
25
    }
242
10
  }
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  void addEhFrameReference(uint32_t offset, const Atom *dest,
245
3
                           Reference::Addend addend = 0) {
246
3
    addReference(Reference::KindNamespace::mach_o, _archHandler.kindArch(),
247
3
                 _archHandler.unwindRefToEhFrameKind(), offset, dest, addend);
248
3
  }
249
250
  void addImageReference(uint32_t offset, const Atom *dest,
251
49
                         Reference::Addend addend = 0) {
252
49
    addReference(Reference::KindNamespace::mach_o, _archHandler.kindArch(),
253
49
                 _archHandler.imageOffsetKind(), offset, dest, addend);
254
49
  }
255
256
2
  void addImageReferenceIndirect(uint32_t offset, const Atom *dest) {
257
2
    addReference(Reference::KindNamespace::mach_o, _archHandler.kindArch(),
258
2
                 _archHandler.imageOffsetKindIndirect(), offset, dest, 0);
259
2
  }
260
261
private:
262
  mach_o::ArchHandler &_archHandler;
263
  std::vector<uint8_t> _contents;
264
  uint32_t _commonEncodingsOffset;
265
  uint32_t _personalityArrayOffset;
266
  uint32_t _topLevelIndexOffset;
267
  uint32_t _lsdaIndexOffset;
268
  uint32_t _firstPageOffset;
269
  bool _isBig;
270
};
271
272
/// Pass for instantiating and optimizing GOT slots.
273
///
274
class CompactUnwindPass : public Pass {
275
public:
276
  CompactUnwindPass(const MachOLinkingContext &context)
277
      : _ctx(context), _archHandler(_ctx.archHandler()),
278
        _file(*_ctx.make_file<MachOFile>("<mach-o Compact Unwind Pass>")),
279
86
        _isBig(MachOLinkingContext::isBigEndian(_ctx.arch())) {
280
86
    _file.setOrdinal(_ctx.getNextOrdinalAndIncrement());
281
86
  }
282
283
private:
284
86
  llvm::Error perform(SimpleFile &mergedFile) override {
285
86
    DEBUG(llvm::dbgs() << "MachO Compact Unwind pass\n");
286
86
287
86
    std::map<const Atom *, CompactUnwindEntry> unwindLocs;
288
86
    std::map<const Atom *, const Atom *> dwarfFrames;
289
86
    std::vector<const Atom *> personalities;
290
86
    uint32_t numLSDAs = 0;
291
86
292
86
    // First collect all __compact_unwind and __eh_frame entries, addressable by
293
86
    // the function referred to.
294
86
    collectCompactUnwindEntries(mergedFile, unwindLocs, personalities,
295
86
                                numLSDAs);
296
86
297
86
    collectDwarfFrameEntries(mergedFile, dwarfFrames);
298
86
299
86
    // Skip rest of pass if no unwind info.
300
86
    if (
unwindLocs.empty() && 86
dwarfFrames.empty()76
)
301
76
      return llvm::Error::success();
302
10
303
10
    // FIXME: if there are more than 4 personality functions then we need to
304
10
    // defer to DWARF info for the ones we don't put in the list. They should
305
10
    // also probably be sorted by frequency.
306
86
    assert(personalities.size() <= 4);
307
10
308
10
    // TODO: Find commmon encodings for use by compressed pages.
309
10
    std::vector<uint32_t> commonEncodings;
310
10
311
10
    // Now sort the entries by final address and fixup the compact encoding to
312
10
    // its final form (i.e. set personality function bits & create DWARF
313
10
    // references where needed).
314
10
    std::vector<CompactUnwindEntry> unwindInfos = createUnwindInfoEntries(
315
10
        mergedFile, unwindLocs, personalities, dwarfFrames);
316
10
317
10
    // Remove any unused eh-frame atoms.
318
10
    pruneUnusedEHFrames(mergedFile, unwindInfos, unwindLocs, dwarfFrames);
319
10
320
10
    // Finally, we can start creating pages based on these entries.
321
10
322
10
    DEBUG(llvm::dbgs() << "  Splitting entries into pages\n");
323
10
    // FIXME: we split the entries into pages naively: lots of 4k pages followed
324
10
    // by a small one. ld64 tried to minimize space and align them to real 4k
325
10
    // boundaries. That might be worth doing, or perhaps we could perform some
326
10
    // minor balancing for expected number of lookups.
327
10
    std::vector<UnwindInfoPage> pages;
328
10
    auto remainingInfos = llvm::makeArrayRef(unwindInfos);
329
10
    do {
330
10
      pages.push_back(UnwindInfoPage());
331
10
332
10
      // FIXME: we only create regular pages at the moment. These can hold up to
333
10
      // 1021 entries according to the documentation.
334
10
      unsigned entriesInPage = std::min(1021U, (unsigned)remainingInfos.size());
335
10
336
10
      pages.back().entries = remainingInfos.slice(0, entriesInPage);
337
10
      remainingInfos = remainingInfos.slice(entriesInPage);
338
10
339
10
      DEBUG(llvm::dbgs()
340
10
            << "    Page from " << pages.back().entries[0].rangeStart->name()
341
10
            << " to " << pages.back().entries.back().rangeStart->name() << " + "
342
10
            << llvm::format("0x%x", pages.back().entries.back().rangeLength)
343
10
            << " has " << entriesInPage << " entries\n");
344
10
    } while (!remainingInfos.empty());
345
10
346
10
    auto *unwind = new (_file.allocator())
347
10
        UnwindInfoAtom(_archHandler, _file, _isBig, personalities,
348
10
                       commonEncodings, pages, numLSDAs);
349
10
    mergedFile.addAtom(*unwind);
350
10
351
10
    // Finally, remove all __compact_unwind atoms now that we've processed them.
352
119
    mergedFile.removeDefinedAtomsIf([](const DefinedAtom *atom) {
353
119
      return atom->contentType() == DefinedAtom::typeCompactUnwindInfo;
354
119
    });
355
86
356
86
    return llvm::Error::success();
357
86
  }
358
359
  void collectCompactUnwindEntries(
360
      const SimpleFile &mergedFile,
361
      std::map<const Atom *, CompactUnwindEntry> &unwindLocs,
362
86
      std::vector<const Atom *> &personalities, uint32_t &numLSDAs) {
363
86
    DEBUG(llvm::dbgs() << "  Collecting __compact_unwind entries\n");
364
86
365
482
    for (const DefinedAtom *atom : mergedFile.defined()) {
366
482
      if (atom->contentType() != DefinedAtom::typeCompactUnwindInfo)
367
467
        continue;
368
15
369
15
      auto unwindEntry = extractCompactUnwindEntry(atom);
370
15
      unwindLocs.insert(std::make_pair(unwindEntry.rangeStart, unwindEntry));
371
15
372
15
      DEBUG(llvm::dbgs() << "    Entry for " << unwindEntry.rangeStart->name()
373
15
                         << ", encoding="
374
15
                         << llvm::format("0x%08x", unwindEntry.encoding));
375
15
      if (unwindEntry.personalityFunction)
376
15
        DEBUG(llvm::dbgs() << ", personality="
377
15
                           << unwindEntry.personalityFunction->name()
378
15
                           << ", lsdaLoc=" << unwindEntry.lsdaLocation->name());
379
15
      DEBUG(llvm::dbgs() << '\n');
380
15
381
15
      // Count number of LSDAs we see, since we need to know how big the index
382
15
      // will be while laying out the section.
383
15
      if (unwindEntry.lsdaLocation)
384
2
        ++numLSDAs;
385
15
386
15
      // Gather the personality functions now, so that they're in deterministic
387
15
      // order (derived from the DefinedAtom order).
388
15
      if (
unwindEntry.personalityFunction15
) {
389
2
        auto pFunc = std::find(personalities.begin(), personalities.end(),
390
2
                               unwindEntry.personalityFunction);
391
2
        if (pFunc == personalities.end())
392
2
          personalities.push_back(unwindEntry.personalityFunction);
393
2
      }
394
482
    }
395
86
  }
396
397
15
  CompactUnwindEntry extractCompactUnwindEntry(const DefinedAtom *atom) {
398
15
    CompactUnwindEntry entry;
399
15
400
18
    for (const Reference *ref : *atom) {
401
18
      switch (ref->offsetInAtom()) {
402
14
      case 0:
403
14
        // FIXME: there could legitimately be functions with multiple encoding
404
14
        // entries. However, nothing produces them at the moment.
405
14
        assert(ref->addend() == 0 && "unexpected offset into function");
406
14
        entry.rangeStart = ref->target();
407
14
        break;
408
2
      case 0x10:
409
2
        assert(ref->addend() == 0 && "unexpected offset into personality fn");
410
2
        entry.personalityFunction = ref->target();
411
2
        break;
412
2
      case 0x18:
413
2
        assert(ref->addend() == 0 && "unexpected offset into LSDA atom");
414
2
        entry.lsdaLocation = ref->target();
415
2
        break;
416
15
      }
417
15
    }
418
15
419
15
    
if (15
atom->rawContent().size() < 4 * sizeof(uint32_t)15
)
420
1
      return entry;
421
14
422
14
    using normalized::read32;
423
14
    entry.rangeLength =
424
14
        read32(atom->rawContent().data() + 2 * sizeof(uint32_t), _isBig);
425
14
    entry.encoding =
426
14
        read32(atom->rawContent().data() + 3 * sizeof(uint32_t), _isBig);
427
14
    return entry;
428
14
  }
429
430
  void
431
  collectDwarfFrameEntries(const SimpleFile &mergedFile,
432
86
                           std::map<const Atom *, const Atom *> &dwarfFrames) {
433
482
    for (const DefinedAtom *ehFrameAtom : mergedFile.defined()) {
434
482
      if (ehFrameAtom->contentType() != DefinedAtom::typeCFI)
435
460
        continue;
436
22
      
if (22
ArchHandler::isDwarfCIE(_isBig, ehFrameAtom)22
)
437
10
        continue;
438
12
439
12
      
if (const Atom *12
function12
= _archHandler.fdeTargetFunction(ehFrameAtom))
440
12
        dwarfFrames[function] = ehFrameAtom;
441
482
    }
442
86
  }
443
444
  /// Every atom defined in __TEXT,__text needs an entry in the final
445
  /// __unwind_info section (in order). These comes from two sources:
446
  ///   + Input __compact_unwind sections where possible (after adding the
447
  ///      personality function offset which is only known now).
448
  ///   + A synthesised reference to __eh_frame if there's no __compact_unwind
449
  ///     or too many personality functions to be accommodated.
450
  std::vector<CompactUnwindEntry> createUnwindInfoEntries(
451
      const SimpleFile &mergedFile,
452
      const std::map<const Atom *, CompactUnwindEntry> &unwindLocs,
453
      const std::vector<const Atom *> &personalities,
454
10
      const std::map<const Atom *, const Atom *> &dwarfFrames) {
455
10
    std::vector<CompactUnwindEntry> unwindInfos;
456
10
457
10
    DEBUG(llvm::dbgs() << "  Creating __unwind_info entries\n");
458
10
    // The final order in the __unwind_info section must be derived from the
459
10
    // order of typeCode atoms, since that's how they'll be put into the object
460
10
    // file eventually (yuck!).
461
126
    for (const DefinedAtom *atom : mergedFile.defined()) {
462
126
      if (atom->contentType() != DefinedAtom::typeCode)
463
101
        continue;
464
25
465
25
      unwindInfos.push_back(finalizeUnwindInfoEntryForAtom(
466
25
          atom, unwindLocs, personalities, dwarfFrames));
467
25
468
25
      DEBUG(llvm::dbgs() << "    Entry for " << atom->name()
469
126
                         << ", final encoding="
470
126
                         << llvm::format("0x%08x", unwindInfos.back().encoding)
471
126
                         << '\n');
472
126
    }
473
10
474
10
    return unwindInfos;
475
10
  }
476
477
  /// Remove unused EH frames.
478
  ///
479
  /// An EH frame is considered unused if there is a corresponding compact
480
  /// unwind atom that doesn't require the EH frame.
481
  void pruneUnusedEHFrames(
482
                   SimpleFile &mergedFile,
483
                   const std::vector<CompactUnwindEntry> &unwindInfos,
484
                   const std::map<const Atom *, CompactUnwindEntry> &unwindLocs,
485
10
                   const std::map<const Atom *, const Atom *> &dwarfFrames) {
486
10
487
10
    // Worklist of all 'used' FDEs.
488
10
    std::vector<const DefinedAtom *> usedDwarfWorklist;
489
10
490
10
    // We have to check two conditions when building the worklist:
491
10
    // (1) EH frames used by compact unwind entries.
492
10
    for (auto &entry : unwindInfos)
493
25
      
if (25
entry.ehFrame25
)
494
3
        usedDwarfWorklist.push_back(cast<DefinedAtom>(entry.ehFrame));
495
10
496
10
    // (2) EH frames that reference functions with no corresponding compact
497
10
    //     unwind info.
498
10
    for (auto &entry : dwarfFrames)
499
12
      
if (12
!unwindLocs.count(entry.first)12
)
500
2
        usedDwarfWorklist.push_back(cast<DefinedAtom>(entry.second));
501
10
502
10
    // Add all transitively referenced CFI atoms by processing the worklist.
503
10
    std::set<const Atom *> usedDwarfFrames;
504
20
    while (
!usedDwarfWorklist.empty()20
) {
505
10
      const DefinedAtom *cfiAtom = usedDwarfWorklist.back();
506
10
      usedDwarfWorklist.pop_back();
507
10
      usedDwarfFrames.insert(cfiAtom);
508
10
      for (const auto *ref : *cfiAtom) {
509
10
        const DefinedAtom *cfiTarget = dyn_cast<DefinedAtom>(ref->target());
510
10
        if (cfiTarget->contentType() == DefinedAtom::typeCFI)
511
5
          usedDwarfWorklist.push_back(cfiTarget);
512
10
      }
513
10
    }
514
10
515
10
    // Finally, delete all unreferenced CFI atoms.
516
126
    mergedFile.removeDefinedAtomsIf([&](const DefinedAtom *atom) {
517
126
      if ((atom->contentType() == DefinedAtom::typeCFI) &&
518
22
          !usedDwarfFrames.count(atom))
519
17
        return true;
520
109
      return false;
521
109
    });
522
10
  }
523
524
  CompactUnwindEntry finalizeUnwindInfoEntryForAtom(
525
      const DefinedAtom *function,
526
      const std::map<const Atom *, CompactUnwindEntry> &unwindLocs,
527
      const std::vector<const Atom *> &personalities,
528
25
      const std::map<const Atom *, const Atom *> &dwarfFrames) {
529
25
    auto unwindLoc = unwindLocs.find(function);
530
25
531
25
    CompactUnwindEntry entry;
532
25
    if (
unwindLoc == unwindLocs.end()25
) {
533
11
      // Default entry has correct encoding (0 => no unwind), but we need to
534
11
      // synthesise the function.
535
11
      entry.rangeStart = function;
536
11
      entry.rangeLength = function->size();
537
11
    } else
538
14
      entry = unwindLoc->second;
539
25
540
25
541
25
    // If there's no __compact_unwind entry, or it explicitly says to use
542
25
    // __eh_frame, we need to try and fill in the correct DWARF atom.
543
25
    if (entry.encoding == _archHandler.dwarfCompactUnwindType() ||
544
25
        
entry.encoding == 024
) {
545
12
      auto dwarfFrame = dwarfFrames.find(function);
546
12
      if (
dwarfFrame != dwarfFrames.end()12
) {
547
3
        entry.encoding = _archHandler.dwarfCompactUnwindType();
548
3
        entry.ehFrame = dwarfFrame->second;
549
3
      }
550
12
    }
551
25
552
25
    auto personality = std::find(personalities.begin(), personalities.end(),
553
25
                                 entry.personalityFunction);
554
25
    uint32_t personalityIdx = personality == personalities.end()
555
23
                                  ? 0
556
2
                                  : personality - personalities.begin() + 1;
557
25
558
25
    // FIXME: We should also use DWARF when there isn't enough room for the
559
25
    // personality function in the compact encoding.
560
25
    assert(personalityIdx < 4 && "too many personality functions");
561
25
562
25
    entry.encoding |= personalityIdx << 28;
563
25
564
25
    if (entry.lsdaLocation)
565
2
      entry.encoding |= 1U << 30;
566
25
567
25
    return entry;
568
25
  }
569
570
  const MachOLinkingContext &_ctx;
571
  mach_o::ArchHandler &_archHandler;
572
  MachOFile &_file;
573
  bool _isBig;
574
};
575
576
86
void addCompactUnwindPass(PassManager &pm, const MachOLinkingContext &ctx) {
577
86
  assert(ctx.needsCompactUnwindPass());
578
86
  pm.add(llvm::make_unique<CompactUnwindPass>(ctx));
579
86
}
580
581
} // end namesapce mach_o
582
} // end namesapce lld