Add a specialized LocalUnwinder object.
This object is for doing many local unwinds across different threads
at any point during a program's execution.
Also add LocalUpdatableMaps that will re-read the maps data under certain
circumstances.
This first version does not support jit or dex pc data.
Bug: 74361929
Test: Ran unit tests.
Change-Id: I790662366d3fed677f31b3288182950c494de9ad
diff --git a/libunwindstack/LocalUnwinder.cpp b/libunwindstack/LocalUnwinder.cpp
new file mode 100644
index 0000000..952b332
--- /dev/null
+++ b/libunwindstack/LocalUnwinder.cpp
@@ -0,0 +1,146 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <pthread.h>
+#include <stdint.h>
+
+#include <memory>
+#include <string>
+#include <vector>
+
+#include <unwindstack/Elf.h>
+#include <unwindstack/LocalUnwinder.h>
+#include <unwindstack/MapInfo.h>
+#include <unwindstack/Maps.h>
+#include <unwindstack/Memory.h>
+#include <unwindstack/Regs.h>
+#include <unwindstack/RegsGetLocal.h>
+
+namespace unwindstack {
+
+bool LocalUnwinder::Init() {
+ pthread_rwlock_init(&maps_rwlock_, nullptr);
+
+ // Create the maps.
+ maps_.reset(new unwindstack::LocalUpdatableMaps());
+ if (!maps_->Parse()) {
+ maps_.reset();
+ return false;
+ }
+
+ process_memory_ = unwindstack::Memory::CreateProcessMemory(getpid());
+
+ return true;
+}
+
+bool LocalUnwinder::ShouldSkipLibrary(const std::string& map_name) {
+ for (const std::string& skip_library : skip_libraries_) {
+ if (skip_library == map_name) {
+ return true;
+ }
+ }
+ return false;
+}
+
+MapInfo* LocalUnwinder::GetMapInfo(uint64_t pc) {
+ pthread_rwlock_rdlock(&maps_rwlock_);
+ MapInfo* map_info = maps_->Find(pc);
+ pthread_rwlock_unlock(&maps_rwlock_);
+
+ if (map_info == nullptr) {
+ pthread_rwlock_wrlock(&maps_rwlock_);
+ // This is guaranteed not to invalidate any previous MapInfo objects so
+ // we don't need to worry about any MapInfo* values already in use.
+ if (maps_->Reparse()) {
+ map_info = maps_->Find(pc);
+ }
+ pthread_rwlock_unlock(&maps_rwlock_);
+ }
+
+ return map_info;
+}
+
+bool LocalUnwinder::Unwind(std::vector<LocalFrameData>* frame_info, size_t max_frames) {
+ std::unique_ptr<unwindstack::Regs> regs(unwindstack::Regs::CreateFromLocal());
+ unwindstack::RegsGetLocal(regs.get());
+
+ size_t num_frames = 0;
+ bool adjust_pc = false;
+ while (true) {
+ uint64_t cur_pc = regs->pc();
+ uint64_t cur_sp = regs->sp();
+
+ MapInfo* map_info = GetMapInfo(cur_pc);
+ if (map_info == nullptr) {
+ break;
+ }
+
+ Elf* elf = map_info->GetElf(process_memory_, true);
+ uint64_t rel_pc = elf->GetRelPc(cur_pc, map_info);
+ uint64_t step_pc = rel_pc;
+ uint64_t pc_adjustment;
+ if (adjust_pc) {
+ pc_adjustment = regs->GetPcAdjustment(rel_pc, elf);
+ } else {
+ pc_adjustment = 0;
+ }
+ step_pc -= pc_adjustment;
+ // Skip any locations that are within this library.
+ if (num_frames != 0 || !ShouldSkipLibrary(map_info->name)) {
+ // Add frame information.
+ std::string func_name;
+ uint64_t func_offset;
+ if (elf->GetFunctionName(rel_pc, &func_name, &func_offset)) {
+ frame_info->emplace_back(map_info, cur_pc - pc_adjustment, rel_pc - pc_adjustment,
+ func_name, func_offset);
+ } else {
+ frame_info->emplace_back(map_info, cur_pc - pc_adjustment, rel_pc - pc_adjustment, "", 0);
+ }
+ num_frames++;
+ }
+ if (!elf->valid()) {
+ break;
+ }
+ if (frame_info->size() == max_frames) {
+ break;
+ }
+
+ adjust_pc = true;
+ bool finished;
+ if (!elf->Step(rel_pc, step_pc, regs.get(), process_memory_.get(), &finished) || finished) {
+ break;
+ }
+ // pc and sp are the same, terminate the unwind.
+ if (cur_pc == regs->pc() && cur_sp == regs->sp()) {
+ break;
+ }
+ }
+ return num_frames != 0;
+}
+
+} // namespace unwindstack