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/Maps.cpp b/libunwindstack/Maps.cpp
index bb682ea..e676a5a 100644
--- a/libunwindstack/Maps.cpp
+++ b/libunwindstack/Maps.cpp
@@ -105,4 +105,83 @@
return "/proc/" + std::to_string(pid_) + "/maps";
}
+const std::string LocalUpdatableMaps::GetMapsFile() const {
+ return "/proc/self/maps";
+}
+
+bool LocalUpdatableMaps::Reparse() {
+ // New maps will be added at the end without deleting the old ones.
+ size_t last_map_idx = maps_.size();
+ if (!Parse()) {
+ // Delete any maps added by the Parse call.
+ for (size_t i = last_map_idx; i < maps_.size(); i++) {
+ delete maps_[i];
+ }
+ maps_.resize(last_map_idx);
+ return false;
+ }
+
+ size_t total_entries = maps_.size();
+ size_t search_map_idx = 0;
+ for (size_t new_map_idx = last_map_idx; new_map_idx < maps_.size(); new_map_idx++) {
+ MapInfo* new_map_info = maps_[new_map_idx];
+ uint64_t start = new_map_info->start;
+ uint64_t end = new_map_info->end;
+ uint64_t flags = new_map_info->flags;
+ std::string* name = &new_map_info->name;
+ for (size_t old_map_idx = search_map_idx; old_map_idx < last_map_idx; old_map_idx++) {
+ MapInfo* info = maps_[old_map_idx];
+ if (start == info->start && end == info->end && flags == info->flags && *name == info->name) {
+ // No need to check
+ search_map_idx = old_map_idx + 1;
+ delete new_map_info;
+ maps_[new_map_idx] = nullptr;
+ total_entries--;
+ break;
+ } else if (info->start > start) {
+ // Stop, there isn't going to be a match.
+ search_map_idx = old_map_idx;
+ break;
+ }
+
+ // Never delete these maps, they may be in use. The assumption is
+ // that there will only every be a handfull of these so waiting
+ // to destroy them is not too expensive.
+ saved_maps_.push_back(info);
+ maps_[old_map_idx] = nullptr;
+ total_entries--;
+ }
+ if (search_map_idx >= last_map_idx) {
+ break;
+ }
+ }
+
+ // Now move out any of the maps that never were found.
+ for (size_t i = search_map_idx; i < last_map_idx; i++) {
+ saved_maps_.push_back(maps_[i]);
+ maps_[i] = nullptr;
+ total_entries--;
+ }
+
+ // Sort all of the values such that the nullptrs wind up at the end, then
+ // resize them away.
+ std::sort(maps_.begin(), maps_.end(), [](const auto* a, const auto* b) {
+ if (a == nullptr) {
+ return false;
+ } else if (b == nullptr) {
+ return true;
+ }
+ return a->start < b->start;
+ });
+ maps_.resize(total_entries);
+
+ return true;
+}
+
+LocalUpdatableMaps::~LocalUpdatableMaps() {
+ for (auto map_info : saved_maps_) {
+ delete map_info;
+ }
+}
+
} // namespace unwindstack