2502a60ea1
Bug: 68047085 Test: Ran new unit tests, verified new unwinder does not show an Test: extra pc zero frame for arm 32 bit processes. Change-Id: Ic6532e56fbb786a8b7d41638abae777c2d0f1d59
137 lines
3.9 KiB
C++
137 lines
3.9 KiB
C++
/*
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* Copyright (C) 2016 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <elf.h>
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#include <stdint.h>
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#include <unwindstack/Memory.h>
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#include <unwindstack/Regs.h>
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#include "ArmExidx.h"
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#include "ElfInterfaceArm.h"
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#include "Machine.h"
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namespace unwindstack {
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bool ElfInterfaceArm::FindEntry(uint32_t pc, uint64_t* entry_offset) {
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if (start_offset_ == 0 || total_entries_ == 0) {
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return false;
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}
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size_t first = 0;
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size_t last = total_entries_;
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while (first < last) {
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size_t current = (first + last) / 2;
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uint32_t addr = addrs_[current];
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if (addr == 0) {
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if (!GetPrel31Addr(start_offset_ + current * 8, &addr)) {
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return false;
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}
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addrs_[current] = addr;
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}
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if (pc == addr) {
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*entry_offset = start_offset_ + current * 8;
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return true;
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}
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if (pc < addr) {
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last = current;
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} else {
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first = current + 1;
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}
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}
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if (last != 0) {
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*entry_offset = start_offset_ + (last - 1) * 8;
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return true;
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}
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return false;
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}
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bool ElfInterfaceArm::GetPrel31Addr(uint32_t offset, uint32_t* addr) {
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uint32_t data;
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if (!memory_->Read32(offset, &data)) {
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return false;
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}
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// Sign extend the value if necessary.
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int32_t value = (static_cast<int32_t>(data) << 1) >> 1;
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*addr = offset + value;
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return true;
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}
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#if !defined(PT_ARM_EXIDX)
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#define PT_ARM_EXIDX 0x70000001
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#endif
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bool ElfInterfaceArm::HandleType(uint64_t offset, uint32_t type, uint64_t load_bias) {
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if (type != PT_ARM_EXIDX) {
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return false;
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}
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Elf32_Phdr phdr;
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if (!memory_->ReadField(offset, &phdr, &phdr.p_vaddr, sizeof(phdr.p_vaddr))) {
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return true;
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}
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if (!memory_->ReadField(offset, &phdr, &phdr.p_memsz, sizeof(phdr.p_memsz))) {
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return true;
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}
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start_offset_ = phdr.p_vaddr - load_bias;
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total_entries_ = phdr.p_memsz / 8;
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return true;
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}
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bool ElfInterfaceArm::Step(uint64_t pc, Regs* regs, Memory* process_memory, bool* finished) {
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// Dwarf unwind information is precise about whether a pc is covered or not,
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// but arm unwind information only has ranges of pc. In order to avoid
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// incorrectly doing a bad unwind using arm unwind information for a
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// different function, always try and unwind with the dwarf information first.
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return ElfInterface32::Step(pc, regs, process_memory, finished) ||
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StepExidx(pc, regs, process_memory, finished);
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}
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bool ElfInterfaceArm::StepExidx(uint64_t pc, Regs* regs, Memory* process_memory, bool* finished) {
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RegsArm* regs_arm = reinterpret_cast<RegsArm*>(regs);
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uint64_t entry_offset;
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if (!FindEntry(pc, &entry_offset)) {
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return false;
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}
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ArmExidx arm(regs_arm, memory_, process_memory);
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arm.set_cfa(regs_arm->sp());
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bool return_value = false;
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if (arm.ExtractEntryData(entry_offset) && arm.Eval()) {
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// If the pc was not set, then use the LR registers for the PC.
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if (!arm.pc_set()) {
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regs_arm->set_pc((*regs_arm)[ARM_REG_LR]);
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(*regs_arm)[ARM_REG_PC] = regs_arm->pc();
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} else {
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regs_arm->set_pc((*regs_arm)[ARM_REG_PC]);
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}
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regs_arm->set_sp(arm.cfa());
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(*regs_arm)[ARM_REG_SP] = regs_arm->sp();
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return_value = true;
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// If the pc was set to zero, consider this the final frame.
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*finished = (regs_arm->pc() == 0) ? true : false;
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}
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if (arm.status() == ARM_STATUS_NO_UNWIND) {
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*finished = true;
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return true;
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}
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return return_value;
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}
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} // namespace unwindstack
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