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/*
* Copyright (C) 2020 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 "src/profiling/common/callstack_trie.h"
#include <vector>
#include "perfetto/ext/base/string_splitter.h"
#include "src/profiling/common/interner.h"
#include "src/profiling/common/unwind_support.h"
namespace perfetto {
namespace profiling {
GlobalCallstackTrie::Node* GlobalCallstackTrie::GetOrCreateChild(
Node* self,
const Interned<Frame>& loc) {
Node* child = self->GetChild(loc);
if (!child)
child = self->AddChild(loc, ++next_callstack_id_, self);
return child;
}
std::vector<Interned<Frame>> GlobalCallstackTrie::BuildInverseCallstack(
const Node* node) const {
std::vector<Interned<Frame>> res;
while (node != &root_) {
res.emplace_back(node->location_);
node = node->parent_;
}
return res;
}
GlobalCallstackTrie::Node* GlobalCallstackTrie::CreateCallsite(
const std::vector<unwindstack::FrameData>& callstack,
const std::vector<std::string>& build_ids) {
PERFETTO_CHECK(callstack.size() == build_ids.size());
Node* node = &root_;
// libunwindstack gives the frames top-first, but we want to bookkeep and
// emit as bottom first.
auto callstack_it = callstack.crbegin();
auto build_id_it = build_ids.crbegin();
for (; callstack_it != callstack.crend() && build_id_it != build_ids.crend();
++callstack_it, ++build_id_it) {
const unwindstack::FrameData& loc = *callstack_it;
const std::string& build_id = *build_id_it;
node = GetOrCreateChild(node, InternCodeLocation(loc, build_id));
}
return node;
}
GlobalCallstackTrie::Node* GlobalCallstackTrie::CreateCallsite(
const std::vector<Interned<Frame>>& callstack) {
Node* node = &root_;
// libunwindstack gives the frames top-first, but we want to bookkeep and
// emit as bottom first.
for (auto it = callstack.crbegin(); it != callstack.crend(); ++it) {
const Interned<Frame>& loc = *it;
node = GetOrCreateChild(node, loc);
}
return node;
}
void GlobalCallstackTrie::IncrementNode(Node* node) {
while (node != nullptr) {
node->ref_count_ += 1;
node = node->parent_;
}
}
void GlobalCallstackTrie::DecrementNode(Node* node) {
PERFETTO_DCHECK(node->ref_count_ >= 1);
bool delete_prev = false;
Node* prev = nullptr;
while (node != nullptr) {
if (delete_prev)
node->RemoveChild(prev);
node->ref_count_ -= 1;
delete_prev = node->ref_count_ == 0;
prev = node;
node = node->parent_;
}
}
Interned<Frame> GlobalCallstackTrie::InternCodeLocation(
const unwindstack::FrameData& loc,
const std::string& build_id) {
Mapping map(string_interner_.Intern(build_id));
map.exact_offset = loc.map_exact_offset;
map.start_offset = loc.map_elf_start_offset;
map.start = loc.map_start;
map.end = loc.map_end;
map.load_bias = loc.map_load_bias;
base::StringSplitter sp(loc.map_name, '/');
while (sp.Next())
map.path_components.emplace_back(string_interner_.Intern(sp.cur_token()));
Frame frame(mapping_interner_.Intern(std::move(map)),
string_interner_.Intern(loc.function_name), loc.rel_pc);
return frame_interner_.Intern(frame);
}
Interned<Frame> GlobalCallstackTrie::MakeRootFrame() {
Mapping map(string_interner_.Intern(""));
Frame frame(mapping_interner_.Intern(std::move(map)),
string_interner_.Intern(""), 0);
return frame_interner_.Intern(frame);
}
GlobalCallstackTrie::Node* GlobalCallstackTrie::Node::AddChild(
const Interned<Frame>& loc,
uint64_t callstack_id,
Node* parent) {
auto it = children_.emplace(loc, callstack_id, parent);
return const_cast<Node*>(&(*it.first));
}
void GlobalCallstackTrie::Node::RemoveChild(Node* node) {
children_.erase(*node);
}
GlobalCallstackTrie::Node* GlobalCallstackTrie::Node::GetChild(
const Interned<Frame>& loc) {
// This will be nicer with C++14 transparent comparators.
// Then we will be able to look up by just the key using a sutiable
// comparator.
//
// For now we need to allow to construct Node from the key.
Node node(loc);
auto it = children_.find(node);
if (it == children_.end())
return nullptr;
return const_cast<Node*>(&(*it));
}
} // namespace profiling
} // namespace perfetto
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