platform_system_core/libunwindstack/DwarfEhFrameWithHdr.h
Christopher Ferris 22d8e8e12f Remove sequential search from DwarfEhFrameWithHdr.
Since there has never been a time that a sequential search has been
necessary, simply remove the sequential code and allow the DwarfEhFrame
object to be used in that case. If this does come up regularly, I'm not
sure that it wouldn't be more performant to use the DwarfEhFrame object
regardless.

Bug: 129550015

Test: libunwindstack unit tests, libbacktrace unit tests.
Change-Id: I738e81accb9bc1e182168cddc9c0c22823e3369b
2019-03-29 14:08:37 -07:00

91 lines
2.6 KiB
C++

/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef _LIBUNWINDSTACK_DWARF_EH_FRAME_WITH_HDR_H
#define _LIBUNWINDSTACK_DWARF_EH_FRAME_WITH_HDR_H
#include <stdint.h>
#include <unordered_map>
#include <unwindstack/DwarfSection.h>
namespace unwindstack {
// Forward declarations.
class Memory;
template <typename AddressType>
class DwarfEhFrameWithHdr : public DwarfSectionImpl<AddressType> {
public:
// Add these so that the protected members of DwarfSectionImpl
// can be accessed without needing a this->.
using DwarfSectionImpl<AddressType>::memory_;
using DwarfSectionImpl<AddressType>::pc_offset_;
using DwarfSectionImpl<AddressType>::entries_offset_;
using DwarfSectionImpl<AddressType>::entries_end_;
using DwarfSectionImpl<AddressType>::last_error_;
using DwarfSectionImpl<AddressType>::load_bias_;
struct FdeInfo {
AddressType pc;
uint64_t offset;
};
DwarfEhFrameWithHdr(Memory* memory) : DwarfSectionImpl<AddressType>(memory) {}
virtual ~DwarfEhFrameWithHdr() = default;
uint64_t GetCieOffsetFromFde32(uint32_t pointer) override {
return this->memory_.cur_offset() - pointer - 4;
}
uint64_t GetCieOffsetFromFde64(uint64_t pointer) override {
return this->memory_.cur_offset() - pointer - 8;
}
uint64_t AdjustPcFromFde(uint64_t pc) override {
// The eh_frame uses relative pcs.
return pc + this->memory_.cur_offset() - 4;
}
bool Init(uint64_t offset, uint64_t size, uint64_t load_bias) override;
const DwarfFde* GetFdeFromPc(uint64_t pc) override;
bool GetFdeOffsetFromPc(uint64_t pc, uint64_t* fde_offset);
const FdeInfo* GetFdeInfoFromIndex(size_t index);
void GetFdes(std::vector<const DwarfFde*>* fdes) override;
protected:
uint8_t version_;
uint8_t ptr_encoding_;
uint8_t table_encoding_;
size_t table_entry_size_;
uint64_t ptr_offset_;
uint64_t entries_data_offset_;
uint64_t cur_entries_offset_ = 0;
uint64_t fde_count_;
std::unordered_map<uint64_t, FdeInfo> fde_info_;
};
} // namespace unwindstack
#endif // _LIBUNWINDSTACK_DWARF_EH_FRAME_WITH_HDR_H