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/*
* Copyright (C) 2017 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.
*/
#include <elf.h>
#include <inttypes.h>
#include <stdint.h>
#include <sys/types.h>
#include <unistd.h>
#include <android-base/stringprintf.h>
#include <unwindstack/Elf.h>
#include <unwindstack/MapInfo.h>
#include <unwindstack/Unwinder.h>
namespace unwindstack {
void Unwinder::FillInFrame(MapInfo* map_info, uint64_t* rel_pc) {
size_t frame_num = frames_.size();
frames_.resize(frame_num + 1);
FrameData* frame = &frames_.at(frame_num);
frame->num = frame_num;
frame->pc = regs_->pc();
frame->sp = regs_->sp();
frame->rel_pc = frame->pc;
if (map_info == nullptr) {
return;
}
Elf* elf = map_info->GetElf(process_memory_, true);
*rel_pc = elf->GetRelPc(regs_->pc(), map_info);
if (frame_num != 0) {
// Don't adjust the first frame pc.
frame->rel_pc = regs_->GetAdjustedPc(*rel_pc, elf);
// Adjust the original pc.
frame->pc -= *rel_pc - frame->rel_pc;
} else {
frame->rel_pc = *rel_pc;
}
frame->map_name = map_info->name;
frame->map_offset = map_info->elf_offset;
frame->map_start = map_info->start;
frame->map_end = map_info->end;
if (!elf->GetFunctionName(frame->rel_pc, &frame->function_name, &frame->function_offset)) {
frame->function_name = "";
frame->function_offset = 0;
}
}
void Unwinder::Unwind() {
frames_.clear();
bool return_address_attempt = false;
for (; frames_.size() < max_frames_;) {
MapInfo* map_info = maps_->Find(regs_->pc());
uint64_t rel_pc;
FillInFrame(map_info, &rel_pc);
bool stepped;
if (map_info == nullptr) {
stepped = false;
} else {
bool finished;
stepped = map_info->elf->Step(rel_pc + map_info->elf_offset, regs_, process_memory_.get(),
&finished);
if (stepped && finished) {
break;
}
}
if (!stepped) {
if (return_address_attempt) {
// Remove the speculative frame.
frames_.pop_back();
break;
} else {
// Steping didn't work, try this secondary method.
if (!regs_->SetPcFromReturnAddress(process_memory_.get())) {
break;
}
return_address_attempt = true;
}
} else {
return_address_attempt = false;
}
}
}
std::string Unwinder::FormatFrame(size_t frame_num) {
if (frame_num >= frames_.size()) {
return "";
}
return FormatFrame(frames_[frame_num],
regs_->MachineType() == EM_ARM || regs_->MachineType() == EM_386);
}
std::string Unwinder::FormatFrame(const FrameData& frame, bool bits32) {
std::string data;
if (bits32) {
data += android::base::StringPrintf(" #%02zu pc %08" PRIx64, frame.num, frame.rel_pc);
} else {
data += android::base::StringPrintf(" #%02zu pc %016" PRIx64, frame.num, frame.rel_pc);
}
if (frame.map_offset != 0) {
data += android::base::StringPrintf(" (offset 0x%" PRIx64 ")", frame.map_offset);
}
if (frame.map_start == frame.map_end) {
// No valid map associated with this frame.
data += " <unknown>";
} else if (!frame.map_name.empty()) {
data += " " + frame.map_name;
} else {
data += android::base::StringPrintf(" <anonymous:%" PRIx64 ">", frame.map_start);
}
if (!frame.function_name.empty()) {
data += " (" + frame.function_name;
if (frame.function_offset != 0) {
data += android::base::StringPrintf("+%" PRId64, frame.function_offset);
}
data += ')';
}
return data;
}
} // namespace unwindstack
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