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
5 #include "components/zucchini/image_index.h"
6
7 #include <algorithm>
8 #include <utility>
9
10 #include "components/zucchini/algorithm.h"
11 #include "components/zucchini/disassembler.h"
12
13 namespace zucchini {
14
ImageIndex(ConstBufferView image)15 ImageIndex::ImageIndex(ConstBufferView image)
16 : image_(image), type_tags_(image.size(), kNoTypeTag) {}
17
18 ImageIndex::ImageIndex(ImageIndex&&) = default;
19
20 ImageIndex::~ImageIndex() = default;
21
Initialize(Disassembler * disasm)22 bool ImageIndex::Initialize(Disassembler* disasm) {
23 std::vector<ReferenceGroup> ref_groups = disasm->MakeReferenceGroups();
24 for (const auto& group : ref_groups) {
25 // Build pool-to-type mapping.
26 DCHECK_NE(kNoPoolTag, group.pool_tag());
27 TargetPool& target_pool = target_pools_[group.pool_tag()];
28 target_pool.AddType(group.type_tag());
29 target_pool.InsertTargets(std::move(*group.GetReader(disasm)));
30 }
31 for (const auto& group : ref_groups) {
32 // Find and store all references for each type, returns false on finding
33 // any overlap, to signal error.
34 if (!InsertReferences(group.traits(),
35 std::move(*group.GetReader(disasm)))) {
36 return false;
37 }
38 }
39 return true;
40 }
41
IsToken(offset_t location) const42 bool ImageIndex::IsToken(offset_t location) const {
43 TypeTag type = LookupType(location);
44
45 // |location| points into raw data.
46 if (type == kNoTypeTag)
47 return true;
48
49 // |location| points into a Reference.
50 Reference reference = refs(type).at(location);
51 // Only the first byte of a reference is a token.
52 return location == reference.location;
53 }
54
InsertReferences(const ReferenceTypeTraits & traits,ReferenceReader && ref_reader)55 bool ImageIndex::InsertReferences(const ReferenceTypeTraits& traits,
56 ReferenceReader&& ref_reader) {
57 // Store ReferenceSet for current type (of |group|).
58 DCHECK_NE(kNoTypeTag, traits.type_tag);
59 auto result = reference_sets_.emplace(
60 traits.type_tag, ReferenceSet(traits, pool(traits.pool_tag)));
61 DCHECK(result.second);
62
63 result.first->second.InitReferences(std::move(ref_reader));
64 for (auto ref : reference_sets_.at(traits.type_tag)) {
65 DCHECK(RangeIsBounded(ref.location, traits.width, size()));
66 auto cur_type_tag = type_tags_.begin() + ref.location;
67
68 // Check for overlap with existing reference. If found, then invalidate.
69 if (std::any_of(cur_type_tag, cur_type_tag + traits.width,
70 [](TypeTag type) { return type != kNoTypeTag; })) {
71 return false;
72 }
73 std::fill(cur_type_tag, cur_type_tag + traits.width, traits.type_tag);
74 }
75 return true;
76 }
77
78 } // namespace zucchini
79