5 files changed, 242 insertions, 0 deletions

diff --git a/src/video_core/CMakeLists.txt b/src/video_core/CMakeLists.txt
index 8c0e6663b..3dab81769 100644
--- a/src/video_core/CMakeLists.txt
+++ b/src/video_core/CMakeLists.txt
@@ -1,6 +1,8 @@
 add_library(video_core STATIC
     command_processor.cpp
     command_processor.h
+    debug_utils/debug_utils.cpp
+    debug_utils/debug_utils.h
     engines/fermi_2d.cpp
     engines/fermi_2d.h
     engines/maxwell_3d.cpp
diff --git a/src/video_core/debug_utils/debug_utils.cpp b/src/video_core/debug_utils/debug_utils.cpp
new file mode 100644
index 000000000..73fd4d7a3
--- /dev/null
+++ b/src/video_core/debug_utils/debug_utils.cpp
@@ -0,0 +1,66 @@
+// Copyright 2014 Citra Emulator Project
+// Licensed under GPLv2
+// Refer to the license.txt file included.
+
+#include <algorithm>
+#include <condition_variable>
+#include <cstdint>
+#include <cstring>
+#include <fstream>
+#include <map>
+#include <mutex>
+#include <string>
+
+#include "common/assert.h"
+#include "common/bit_field.h"
+#include "common/color.h"
+#include "common/common_types.h"
+#include "common/file_util.h"
+#include "common/logging/log.h"
+#include "common/math_util.h"
+#include "common/vector_math.h"
+#include "video_core/debug_utils/debug_utils.h"
+
+namespace Tegra {
+
+std::shared_ptr<DebugContext> g_debug_context;
+
+void DebugContext::DoOnEvent(Event event, void* data) {
+    {
+        std::unique_lock<std::mutex> lock(breakpoint_mutex);
+
+        // TODO(Subv): Commit the rasterizer's caches so framebuffers, render targets, etc. will
+        // show on debug widgets
+
+        // TODO: Should stop the CPU thread here once we multithread emulation.
+
+        active_breakpoint = event;
+        at_breakpoint = true;
+
+        // Tell all observers that we hit a breakpoint
+        for (auto& breakpoint_observer : breakpoint_observers) {
+            breakpoint_observer->OnMaxwellBreakPointHit(event, data);
+        }
+
+        // Wait until another thread tells us to Resume()
+        resume_from_breakpoint.wait(lock, [&] { return !at_breakpoint; });
+    }
+}
+
+void DebugContext::Resume() {
+    {
+        std::lock_guard<std::mutex> lock(breakpoint_mutex);
+
+        // Tell all observers that we are about to resume
+        for (auto& breakpoint_observer : breakpoint_observers) {
+            breakpoint_observer->OnMaxwellResume();
+        }
+
+        // Resume the waiting thread (i.e. OnEvent())
+        at_breakpoint = false;
+    }
+
+    resume_from_breakpoint.notify_one();
+}
+
+} // namespace Tegra
diff --git a/src/video_core/debug_utils/debug_utils.h b/src/video_core/debug_utils/debug_utils.h
new file mode 100644
index 000000000..98461d6d9
--- /dev/null
+++ b/src/video_core/debug_utils/debug_utils.h
@@ -0,0 +1,165 @@
+// Copyright 2014 Citra Emulator Project
+// Licensed under GPLv2
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <algorithm>
+#include <array>
+#include <condition_variable>
+#include <iterator>
+#include <list>
+#include <map>
+#include <memory>
+#include <mutex>
+#include <string>
+#include <utility>
+#include <vector>
+#include "common/common_types.h"
+#include "common/vector_math.h"
+
+namespace Tegra {
+
+class DebugContext {
+public:
+    enum class Event {
+        FirstEvent = 0,
+
+        MaxwellCommandLoaded = FirstEvent,
+        MaxwellCommandProcessed,
+        IncomingPrimitiveBatch,
+        FinishedPrimitiveBatch,
+
+        NumEvents
+    };
+
+    /**
+     * Inherit from this class to be notified of events registered to some debug context.
+     * Most importantly this is used for our debugger GUI.
+     *
+     * To implement event handling, override the OnMaxwellBreakPointHit and OnMaxwellResume methods.
+     * @warning All BreakPointObservers need to be on the same thread to guarantee thread-safe state
+     * access
+     * @todo Evaluate an alternative interface, in which there is only one managing observer and
+     * multiple child observers running (by design) on the same thread.
+     */
+    class BreakPointObserver {
+    public:
+        /// Constructs the object such that it observes events of the given DebugContext.
+        BreakPointObserver(std::shared_ptr<DebugContext> debug_context)
+            : context_weak(debug_context) {
+            std::unique_lock<std::mutex> lock(debug_context->breakpoint_mutex);
+            debug_context->breakpoint_observers.push_back(this);
+        }
+
+        virtual ~BreakPointObserver() {
+            auto context = context_weak.lock();
+            if (context) {
+                std::unique_lock<std::mutex> lock(context->breakpoint_mutex);
+                context->breakpoint_observers.remove(this);
+
+                // If we are the last observer to be destroyed, tell the debugger context that
+                // it is free to continue. In particular, this is required for a proper yuzu
+                // shutdown, when the emulation thread is waiting at a breakpoint.
+                if (context->breakpoint_observers.empty())
+                    context->Resume();
+            }
+        }
+
+        /**
+         * Action to perform when a breakpoint was reached.
+         * @param event Type of event which triggered the breakpoint
+         * @param data Optional data pointer (if unused, this is a nullptr)
+         * @note This function will perform nothing unless it is overridden in the child class.
+         */
+        virtual void OnMaxwellBreakPointHit(Event event, void* data) {}
+
+        /**
+         * Action to perform when emulation is resumed from a breakpoint.
+         * @note This function will perform nothing unless it is overridden in the child class.
+         */
+        virtual void OnMaxwellResume() {}
+
+    protected:
+        /**
+         * Weak context pointer. This need not be valid, so when requesting a shared_ptr via
+         * context_weak.lock(), always compare the result against nullptr.
+         */
+        std::weak_ptr<DebugContext> context_weak;
+    };
+
+    /**
+     * Simple structure defining a breakpoint state
+     */
+    struct BreakPoint {
+        bool enabled = false;
+    };
+
+    /**
+     * Static constructor used to create a shared_ptr of a DebugContext.
+     */
+    static std::shared_ptr<DebugContext> Construct() {
+        return std::shared_ptr<DebugContext>(new DebugContext);
+    }
+
+    /**
+     * Used by the emulation core when a given event has happened. If a breakpoint has been set
+     * for this event, OnEvent calls the event handlers of the registered breakpoint observers.
+     * The current thread then is halted until Resume() is called from another thread (or until
+     * emulation is stopped).
+     * @param event Event which has happened
+     * @param data Optional data pointer (pass nullptr if unused). Needs to remain valid until
+     * Resume() is called.
+     */
+    void OnEvent(Event event, void* data) {
+        // This check is left in the header to allow the compiler to inline it.
+        if (!breakpoints[(int)event].enabled)
+            return;
+        // For the rest of event handling, call a separate function.
+        DoOnEvent(event, data);
+    }
+
+    void DoOnEvent(Event event, void* data);
+
+    /**
+     * Resume from the current breakpoint.
+     * @warning Calling this from the same thread that OnEvent was called in will cause a deadlock.
+     * Calling from any other thread is safe.
+     */
+    void Resume();
+
+    /**
+     * Delete all set breakpoints and resume emulation.
+     */
+    void ClearBreakpoints() {
+        for (auto& bp : breakpoints) {
+            bp.enabled = false;
+        }
+        Resume();
+    }
+
+    // TODO: Evaluate if access to these members should be hidden behind a public interface.
+    std::array<BreakPoint, (int)Event::NumEvents> breakpoints;
+    Event active_breakpoint;
+    bool at_breakpoint = false;
+
+private:
+    /**
+     * Private default constructor to make sure people always construct this through Construct()
+     * instead.
+     */
+    DebugContext() = default;
+
+    /// Mutex protecting current breakpoint state and the observer list.
+    std::mutex breakpoint_mutex;
+
+    /// Used by OnEvent to wait for resumption.
+    std::condition_variable resume_from_breakpoint;
+
+    /// List of registered observers
+    std::list<BreakPointObserver*> breakpoint_observers;
+};
+
+extern std::shared_ptr<DebugContext> g_debug_context;
+
+} // namespace Tegra
diff --git a/src/video_core/gpu.cpp b/src/video_core/gpu.cpp
index c384d236e..9463cd5d6 100644
--- a/src/video_core/gpu.cpp
+++ b/src/video_core/gpu.cpp
@@ -18,4 +18,8 @@ GPU::GPU() {
 
 GPU::~GPU() = default;
 
+const Tegra::Engines::Maxwell3D& GPU::Get3DEngine() const {
+    return *maxwell_3d;
+}
+
 } // namespace Tegra
diff --git a/src/video_core/gpu.h b/src/video_core/gpu.h
index 206b3e05e..778b63218 100644
--- a/src/video_core/gpu.h
+++ b/src/video_core/gpu.h
@@ -13,6 +13,8 @@
 
 namespace Tegra {
 
+class DebugContext;
+
 /**
  * Struct describing framebuffer configuration
  */
@@ -66,6 +68,9 @@ public:
     /// Processes a command list stored at the specified address in GPU memory.
     void ProcessCommandList(GPUVAddr address, u32 size);
 
+    /// Returns a reference to the Maxwell3D GPU engine.
+    const Engines::Maxwell3D& Get3DEngine() const;
+
     std::unique_ptr<MemoryManager> memory_manager;
 
     Engines::Maxwell3D& Maxwell3D() {