platform_system_core/libunwindstack/ElfInterfaceArm.h
Christopher Ferris 5afddb0637 Remove Memory::ReadField.
In almost all cases, it is faster to read the entire structure rather
than do multiple reads using ReadField. The only case where it would be
slower is if doing a remote unwind and ptrace is the only way to read. In
all other cases, it's a single system call. In the ptrace call, it will be
multiple calls. Given that it is unusual to be forced to use ptrace,
it's better to avoid it.

It also reduces the code complexity to do a single read, and avoids
issues where the code forgets to read the field it needs.

Test: Unit tests pass on host and target.
Change-Id: I7b3875b2c85d0d88115b1776e1be28521dc0b932
2018-07-12 12:45:31 -07:00

97 lines
3 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_ELF_INTERFACE_ARM_H
#define _LIBUNWINDSTACK_ELF_INTERFACE_ARM_H
#include <elf.h>
#include <stdint.h>
#include <iterator>
#include <unordered_map>
#include <unwindstack/ElfInterface.h>
#include <unwindstack/Memory.h>
namespace unwindstack {
class ElfInterfaceArm : public ElfInterface32 {
public:
ElfInterfaceArm(Memory* memory) : ElfInterface32(memory) {}
virtual ~ElfInterfaceArm() = default;
class iterator : public std::iterator<std::bidirectional_iterator_tag, uint32_t> {
public:
iterator(ElfInterfaceArm* interface, size_t index) : interface_(interface), index_(index) { }
iterator& operator++() { index_++; return *this; }
iterator& operator++(int increment) { index_ += increment; return *this; }
iterator& operator--() { index_--; return *this; }
iterator& operator--(int decrement) { index_ -= decrement; return *this; }
bool operator==(const iterator& rhs) { return this->index_ == rhs.index_; }
bool operator!=(const iterator& rhs) { return this->index_ != rhs.index_; }
uint32_t operator*() {
uint32_t addr = interface_->addrs_[index_];
if (addr == 0) {
if (!interface_->GetPrel31Addr(interface_->start_offset_ + index_ * 8, &addr)) {
return 0;
}
interface_->addrs_[index_] = addr;
}
return addr;
}
private:
ElfInterfaceArm* interface_ = nullptr;
size_t index_ = 0;
};
iterator begin() { return iterator(this, 0); }
iterator end() { return iterator(this, total_entries_); }
bool Init(uint64_t* load_bias) override;
bool GetPrel31Addr(uint32_t offset, uint32_t* addr);
bool FindEntry(uint32_t pc, uint64_t* entry_offset);
void HandleUnknownType(uint32_t type, uint64_t ph_offset, uint64_t ph_filesz) override;
bool Step(uint64_t pc, Regs* regs, Memory* process_memory, bool* finished) override;
bool StepExidx(uint64_t pc, Regs* regs, Memory* process_memory, bool* finished);
bool GetFunctionName(uint64_t addr, std::string* name, uint64_t* offset) override;
uint64_t start_offset() { return start_offset_; }
size_t total_entries() { return total_entries_; }
void set_load_bias(uint64_t load_bias) { load_bias_ = load_bias; }
protected:
uint64_t start_offset_ = 0;
size_t total_entries_ = 0;
uint64_t load_bias_ = 0;
std::unordered_map<size_t, uint32_t> addrs_;
};
} // namespace unwindstack
#endif // _LIBUNWINDSTACK_ELF_INTERFACE_ARM_H