Changes for Bug 25251

Summary:
The solution to bug 24074,rL249673 needed
to parse the function information from the Dwarf in order
to set the SymbolContext. For that, GetFunction was called
for the parent in GetTypeForDIE, which parses the
ChildParameters and in the flow, GetTypeForDIE was called
for one of the sibling die and so an infinite
loop was triggered by calling GetFunction repeatedly for the
same function.

The changes in this revision modify the GetTypeForDIE to only
resolve the function context in the Type Lookup flow and so
prevent the infinite loop.

A testcase has also been added to check for regression in the
future and a test vector had been added to the testcase of
24074.

Reviewers: jingham, tberghammer, clayborg

Differential Revision: http://reviews.llvm.org/D14202

llvm-svn: 251917

1 files changed, 151 insertions, 0 deletions

diff --git a/lldb/packages/Python/lldbsuite/test/functionalities/thread/backtrace_all/ParallelTask.cpp b/lldb/packages/Python/lldbsuite/test/functionalities/thread/backtrace_all/ParallelTask.cpp
new file mode 100755
index 00000000000..71fb8e3bb56
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/functionalities/thread/backtrace_all/ParallelTask.cpp
@@ -0,0 +1,151 @@
+#include <cstdint>
+#include <thread>
+#include <vector>
+#include <queue>
+#include <future>
+#include <iostream>
+#include <cassert>
+
+class TaskPoolImpl
+{
+public:
+    TaskPoolImpl(uint32_t num_threads) :
+        m_stop(false)
+    {
+        for (uint32_t i = 0; i < num_threads; ++i)
+            m_threads.emplace_back(Worker, this);
+    }
+
+    ~TaskPoolImpl()
+    {
+        Stop();
+    }
+
+    template<typename F, typename... Args>
+    std::future<typename std::result_of<F(Args...)>::type>
+    AddTask(F&& f, Args&&... args)
+    {
+        auto task = std::make_shared<std::packaged_task<typename std::result_of<F(Args...)>::type()>>(
+            std::bind(std::forward<F>(f), std::forward<Args>(args)...));
+
+        std::unique_lock<std::mutex> lock(m_tasks_mutex);
+        assert(!m_stop && "Can't add task to TaskPool after it is stopped");
+        m_tasks.emplace([task](){ (*task)(); });
+        lock.unlock();
+        m_tasks_cv.notify_one();
+
+        return task->get_future();
+    }
+
+    void
+    Stop()
+    {
+        std::unique_lock<std::mutex> lock(m_tasks_mutex);
+        m_stop = true;
+        m_tasks_mutex.unlock();
+        m_tasks_cv.notify_all();
+        for (auto& t : m_threads)
+            t.join();
+    }
+
+private:
+    static void
+    Worker(TaskPoolImpl* pool)
+    {
+        while (true)
+        {
+            std::unique_lock<std::mutex> lock(pool->m_tasks_mutex);
+            if (pool->m_tasks.empty())
+                pool->m_tasks_cv.wait(lock, [pool](){ return !pool->m_tasks.empty() || pool->m_stop; });
+            if (pool->m_tasks.empty())
+                break;
+
+            std::function<void()> f = pool->m_tasks.front();
+            pool->m_tasks.pop();
+            lock.unlock();
+
+            f();
+        }
+    }
+
+    std::queue<std::function<void()>> m_tasks;
+    std::mutex                        m_tasks_mutex;
+    std::condition_variable           m_tasks_cv;
+    bool                              m_stop;
+    std::vector<std::thread>          m_threads;
+};
+
+class TaskPool
+{
+public:
+    // Add a new task to the thread pool and return a std::future belongs for the newly created task.
+    // The caller of this function have to wait on the future for this task to complete.
+    template<typename F, typename... Args>
+    static std::future<typename std::result_of<F(Args...)>::type>
+    AddTask(F&& f, Args&&... args)
+    {
+        return GetImplementation().AddTask(std::forward<F>(f), std::forward<Args>(args)...);
+    }
+
+    // Run all of the specified tasks on the thread pool and wait until all of them are finished
+    // before returning
+    template<typename... T>
+    static void
+    RunTasks(T&&... t)
+    {
+        RunTaskImpl<T...>::Run(std::forward<T>(t)...);
+    }
+
+private:
+    static TaskPoolImpl&
+    GetImplementation()
+    {
+        static TaskPoolImpl g_task_pool_impl(std::thread::hardware_concurrency());
+        return g_task_pool_impl;
+    }
+
+    template<typename... T>
+    struct RunTaskImpl;
+};
+
+template<typename H, typename... T>
+struct TaskPool::RunTaskImpl<H, T...>
+{
+    static void
+    Run(H&& h, T&&... t)
+    {
+        auto f = AddTask(std::forward<H>(h));
+        RunTaskImpl<T...>::Run(std::forward<T>(t)...);
+        f.wait();
+    }
+};
+
+template<>
+struct TaskPool::RunTaskImpl<>
+{
+    static void
+    Run() {}
+};
+
+int main()
+{
+    std::vector<std::future<uint32_t>> tasks;
+    for (int i = 0; i < 100000; ++i)
+    {
+        tasks.emplace_back(TaskPool::AddTask([](int i){
+            uint32_t s = 0;
+            for (int j = 0; j <= i; ++j)
+                s += j;
+            return s;
+        },
+        i));
+    }
+
+    for (auto& it : tasks)  // Set breakpoint here
+        it.wait();
+
+    TaskPool::RunTasks(
+        []() { return 1; },
+        []() { return "aaaa"; }
+    );
+}