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- // Copyright 2017 The Chromium Authors. All rights reserved.
- // Use of this source code is governed by a BSD-style license that can be
- // found in the LICENSE file.
- #include "components/zucchini/rel32_utils.h"
- #include <algorithm>
- #include "base/check_op.h"
- #include "components/zucchini/io_utils.h"
- namespace zucchini {
- /******** Rel32ReaderX86 ********/
- Rel32ReaderX86::Rel32ReaderX86(ConstBufferView image,
- offset_t lo,
- offset_t hi,
- const std::deque<offset_t>* locations,
- const AddressTranslator& translator)
- : image_(image),
- target_rva_to_offset_(translator),
- location_offset_to_rva_(translator),
- hi_(hi),
- last_(locations->end()) {
- DCHECK_LE(lo, image.size());
- DCHECK_LE(hi, image.size());
- current_ = std::lower_bound(locations->begin(), locations->end(), lo);
- }
- Rel32ReaderX86::~Rel32ReaderX86() = default;
- absl::optional<Reference> Rel32ReaderX86::GetNext() {
- while (current_ < last_ && *current_ < hi_) {
- offset_t loc_offset = *(current_++);
- DCHECK_LE(loc_offset + 4, image_.size()); // Sanity check.
- rva_t loc_rva = location_offset_to_rva_.Convert(loc_offset);
- rva_t target_rva = loc_rva + 4 + image_.read<int32_t>(loc_offset);
- offset_t target_offset = target_rva_to_offset_.Convert(target_rva);
- // |locations| is valid by assumption (see class description).
- DCHECK_NE(kInvalidOffset, target_offset);
- return Reference{loc_offset, target_offset};
- }
- return absl::nullopt;
- }
- /******** Rel32ReceptorX86 ********/
- Rel32WriterX86::Rel32WriterX86(MutableBufferView image,
- const AddressTranslator& translator)
- : image_(image),
- target_offset_to_rva_(translator),
- location_offset_to_rva_(translator) {}
- Rel32WriterX86::~Rel32WriterX86() = default;
- void Rel32WriterX86::PutNext(Reference ref) {
- rva_t target_rva = target_offset_to_rva_.Convert(ref.target);
- rva_t loc_rva = location_offset_to_rva_.Convert(ref.location);
- // Subtraction underflow is okay
- uint32_t code =
- static_cast<uint32_t>(target_rva) - (static_cast<uint32_t>(loc_rva) + 4);
- image_.write<uint32_t>(ref.location, code);
- }
- void OutputArmCopyDispFailure(uint32_t addr_type) {
- // Failed to mix old payload bits with new operation bits. The main cause of
- // this rare failure is when BL (encoding T1) with payload bits representing
- // disp % 4 == 2 transforms into BLX (encoding T2). Error arises because BLX
- // requires payload bits to have disp == 0 (mod 4). Mixing failures are not
- // fatal to patching; we simply fall back to direct copy and forgo benefits
- // from mixing for these cases. TODO(huangs, etiennep): Ongoing discussion on
- // whether we should just nullify all payload disp so we won't have to deal
- // with this case, but at the cost of having Zucchini-apply do more work.
- static int output_quota = 10;
- if (output_quota > 0) {
- LOG(WARNING) << "Reference byte mix failed with type = " << addr_type << "."
- << std::endl;
- --output_quota;
- if (!output_quota)
- LOG(WARNING) << "(Additional output suppressed)";
- }
- }
- } // namespace zucchini
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