image_index.cc 2.6 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778
  1. // Copyright 2017 The Chromium Authors. All rights reserved.
  2. // Use of this source code is governed by a BSD-style license that can be
  3. // found in the LICENSE file.
  4. #include "components/zucchini/image_index.h"
  5. #include <algorithm>
  6. #include <utility>
  7. #include "components/zucchini/algorithm.h"
  8. #include "components/zucchini/disassembler.h"
  9. namespace zucchini {
  10. ImageIndex::ImageIndex(ConstBufferView image)
  11. : image_(image), type_tags_(image.size(), kNoTypeTag) {}
  12. ImageIndex::ImageIndex(ImageIndex&&) = default;
  13. ImageIndex::~ImageIndex() = default;
  14. bool ImageIndex::Initialize(Disassembler* disasm) {
  15. std::vector<ReferenceGroup> ref_groups = disasm->MakeReferenceGroups();
  16. for (const auto& group : ref_groups) {
  17. // Build pool-to-type mapping.
  18. DCHECK_NE(kNoPoolTag, group.pool_tag());
  19. TargetPool& target_pool = target_pools_[group.pool_tag()];
  20. target_pool.AddType(group.type_tag());
  21. target_pool.InsertTargets(std::move(*group.GetReader(disasm)));
  22. }
  23. for (const auto& group : ref_groups) {
  24. // Find and store all references for each type, returns false on finding
  25. // any overlap, to signal error.
  26. if (!InsertReferences(group.traits(),
  27. std::move(*group.GetReader(disasm)))) {
  28. return false;
  29. }
  30. }
  31. return true;
  32. }
  33. bool ImageIndex::IsToken(offset_t location) const {
  34. TypeTag type = LookupType(location);
  35. // |location| points into raw data.
  36. if (type == kNoTypeTag)
  37. return true;
  38. // |location| points into a Reference.
  39. Reference reference = refs(type).at(location);
  40. // Only the first byte of a reference is a token.
  41. return location == reference.location;
  42. }
  43. bool ImageIndex::InsertReferences(const ReferenceTypeTraits& traits,
  44. ReferenceReader&& ref_reader) {
  45. // Store ReferenceSet for current type (of |group|).
  46. DCHECK_NE(kNoTypeTag, traits.type_tag);
  47. auto result = reference_sets_.emplace(
  48. traits.type_tag, ReferenceSet(traits, pool(traits.pool_tag)));
  49. DCHECK(result.second);
  50. result.first->second.InitReferences(std::move(ref_reader));
  51. for (auto ref : reference_sets_.at(traits.type_tag)) {
  52. DCHECK(RangeIsBounded(ref.location, traits.width, size()));
  53. auto cur_type_tag = type_tags_.begin() + ref.location;
  54. // Check for overlap with existing reference. If found, then invalidate.
  55. if (std::any_of(cur_type_tag, cur_type_tag + traits.width,
  56. [](TypeTag type) { return type != kNoTypeTag; })) {
  57. return false;
  58. }
  59. std::fill(cur_type_tag, cur_type_tag + traits.width, traits.type_tag);
  60. }
  61. return true;
  62. }
  63. } // namespace zucchini