platform_system_core/libunwindstack/ElfInterfaceArm.h
Christopher Ferris b9de87f7ed Add a new unwind method on error.
If a function crashes by jumping into unexecutable code, the old method
could not unwind through that. Add a fallback method to set the pc from
the default return address location.

In addition, add a new finished check for steps. This will provide a method
to indicate that this step is the last step. This prevents cases where
the fallback method might be triggered incorrectly.

Update the libbacktrace code to unwind using the new methodology.

Update the unwind tool to use the new unwind methodology.

Add a new option to crasher that calls through a null function.

Create a new object, Unwinder, that encapsulates the a basic unwind. For now,
libbacktrace will still use the custom code.

Added new unit tests to cover the new cases. Also add a test that
crashes calling a nullptr as a function, and then has call frames in
the signal stack.

Bug: 65842173

Test: Pass all unit tests, verify crasher dumps properly.
Change-Id: Ia18430ab107e9f7bdf0e14a9b74710b1280bd7f4
2017-09-22 16:55:12 -07:00

94 lines
2.9 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 GetPrel31Addr(uint32_t offset, uint32_t* addr);
bool FindEntry(uint32_t pc, uint64_t* entry_offset);
bool HandleType(uint64_t offset, uint32_t type) 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);
uint64_t start_offset() { return start_offset_; }
void set_start_offset(uint64_t start_offset) { start_offset_ = start_offset; }
size_t total_entries() { return total_entries_; }
void set_total_entries(size_t total_entries) { total_entries_ = total_entries; }
private:
uint64_t start_offset_ = 0;
size_t total_entries_ = 0;
std::unordered_map<size_t, uint32_t> addrs_;
};
} // namespace unwindstack
#endif // _LIBUNWINDSTACK_ELF_INTERFACE_ARM_H