Allocate a general purpose GPU-side debug tracing buffer

Can be used for checkpoints, etc.

app/src/main/cpp/skyline/gpu.cpp

@@ -402,7 +402,8 @@ namespace skyline::gpu {
           descriptor(*this),
           helperShaders(*this, state.os->assetFileSystem),
           renderPassCache(*this),
-          framebufferCache(*this) {}
+          framebufferCache(*this),
+          debugTracingBuffer(memory.AllocateBuffer(DebugTracingBufferSize)) {}
 
     void GPU::Initialise() {
         std::string titleId{state.loader->nacp->GetSaveDataOwnerId()};

app/src/main/cpp/skyline/gpu.h

@@ -68,6 +68,9 @@ namespace skyline::gpu {
         std::optional<interconnect::maxwell3d::PipelineManager> graphicsPipelineManager;
         interconnect::kepler_compute::PipelineManager computePipelineManager;
 
+        static constexpr size_t DebugTracingBufferSize{0x80000}; //!< 512KiB
+        memory::Buffer debugTracingBuffer; //!< General use buffer for debug tracing, first 4 bytes are allocated for checkpoints
+
         GPU(const DeviceState &state);
 
         /**