From 1b4f0bf32aa5215325ca33f81898a7eeef9da2f8 Mon Sep 17 00:00:00 2001
From: Sergey Sharybin <sergey@blender.org>
Date: Mon, 3 May 2021 15:07:14 +0200
Subject: Fix T87989: Crash using OpenCL in compositor

Initial report was mentioning the Classroom demo scene, but this is
probably because the scene was pre-configured to be used with OpenCL.
Would expect any OpenCL compositing to be failing prior to this fix.

The reason why crash was happening is due to OpenCL queue being
released from OpenCLDevice destructor. Is not that obvious, but
when Vector (including std::vector) is holding elements by value
a destructor will be called on "old" memory when vector capacitance
changes.

Solved by making forbidding copy semantic for compositor devices and
forcing move semantic to be used.

Also use emplace semantic in the devices vector initialization.
---
 source/blender/compositor/intern/COM_Device.h         |  8 ++++++++
 source/blender/compositor/intern/COM_OpenCLDevice.cc  | 10 ++++++++++
 source/blender/compositor/intern/COM_OpenCLDevice.h   |  3 +++
 source/blender/compositor/intern/COM_WorkScheduler.cc | 10 +++++-----
 4 files changed, 26 insertions(+), 5 deletions(-)

(limited to 'source/blender/compositor/intern')

diff --git a/source/blender/compositor/intern/COM_Device.h b/source/blender/compositor/intern/COM_Device.h
index 2a43c1be2b4..c848672a405 100644
--- a/source/blender/compositor/intern/COM_Device.h
+++ b/source/blender/compositor/intern/COM_Device.h
@@ -30,6 +30,14 @@ namespace blender::compositor {
 class Device {
 
  public:
+  Device() = default;
+
+  Device(const Device &other) = delete;
+  Device(Device &&other) noexcept = default;
+
+  Device &operator=(const Device &other) = delete;
+  Device &operator=(Device &&other) = delete;
+
   /**
    * \brief Declaration of the virtual destructor
    * \note resolve warning gcc 4.7
diff --git a/source/blender/compositor/intern/COM_OpenCLDevice.cc b/source/blender/compositor/intern/COM_OpenCLDevice.cc
index b96dbe91434..0f6ed0dbd2b 100644
--- a/source/blender/compositor/intern/COM_OpenCLDevice.cc
+++ b/source/blender/compositor/intern/COM_OpenCLDevice.cc
@@ -50,6 +50,16 @@ OpenCLDevice::OpenCLDevice(cl_context context,
   this->m_queue = clCreateCommandQueue(this->m_context, this->m_device, 0, &error);
 }
 
+OpenCLDevice::OpenCLDevice(OpenCLDevice &&other) noexcept
+    : m_context(other.m_context),
+      m_device(other.m_device),
+      m_program(other.m_program),
+      m_queue(other.m_queue),
+      m_vendorID(other.m_vendorID)
+{
+  other.m_queue = nullptr;
+}
+
 OpenCLDevice::~OpenCLDevice()
 {
   if (this->m_queue) {
diff --git a/source/blender/compositor/intern/COM_OpenCLDevice.h b/source/blender/compositor/intern/COM_OpenCLDevice.h
index 355451cef68..826b0457a49 100644
--- a/source/blender/compositor/intern/COM_OpenCLDevice.h
+++ b/source/blender/compositor/intern/COM_OpenCLDevice.h
@@ -67,6 +67,9 @@ class OpenCLDevice : public Device {
    * \param vendorID:
    */
   OpenCLDevice(cl_context context, cl_device_id device, cl_program program, cl_int vendorId);
+
+  OpenCLDevice(OpenCLDevice &&other) noexcept;
+
   ~OpenCLDevice();
 
   /**
diff --git a/source/blender/compositor/intern/COM_WorkScheduler.cc b/source/blender/compositor/intern/COM_WorkScheduler.cc
index ee3a6dedd44..d578ac24a4a 100644
--- a/source/blender/compositor/intern/COM_WorkScheduler.cc
+++ b/source/blender/compositor/intern/COM_WorkScheduler.cc
@@ -263,10 +263,10 @@ static void opencl_initialize(const bool use_opencl)
             if (error2 != CL_SUCCESS) {
               printf("CLERROR[%d]: %s\n", error2, clewErrorString(error2));
             }
-            g_work_scheduler.opencl.devices.append(OpenCLDevice(g_work_scheduler.opencl.context,
-                                                                device,
-                                                                g_work_scheduler.opencl.program,
-                                                                vendorID));
+            g_work_scheduler.opencl.devices.append_as(g_work_scheduler.opencl.context,
+                                                      device,
+                                                      g_work_scheduler.opencl.program,
+                                                      vendorID);
           }
         }
         MEM_freeN(cldevices);
@@ -368,7 +368,7 @@ static void threading_model_queue_initialize(const int num_cpu_threads)
   /* Initialize CPU threads. */
   if (!g_work_scheduler.queue.initialized) {
     for (int index = 0; index < num_cpu_threads; index++) {
-      g_work_scheduler.queue.devices.append(CPUDevice(index));
+      g_work_scheduler.queue.devices.append_as(index);
     }
     BLI_thread_local_create(g_thread_device);
     g_work_scheduler.queue.initialized = true;
-- 
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