Samuel Huang | 06f1ae9 | 2018-03-13 18:19:34 +0000 | [diff] [blame] | 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 | |
| 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 | |
| 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 | |
| 42 | 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. |
Etienne Pierre-doray | 8f9a9e7 | 2018-08-13 18:49:00 +0000 | [diff] [blame] | 50 | Reference reference = refs(type).at(location); |
Samuel Huang | 06f1ae9 | 2018-03-13 18:19:34 +0000 | [diff] [blame] | 51 | // Only the first byte of a reference is a token. |
| 52 | return location == reference.location; |
| 53 | } |
| 54 | |
| 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 |