igl | vulkan | Implement VulkanImmediateCommands::nextSubmitHandle()

Summary:
Implemented `VulkanImmediateCommands::nextSubmitHandle()`.

This way there's no need to store a pointer or reference to the current command buffer wrapper. This is a much cleaner approach.

Backported corporateshark@5ceaf6c.

Reviewed By: EricGriffith, pixelperfect3, mmaurer

Differential Revision: D62999820

fbshipit-source-id: 6205f6f1c1d72b73316af3e5176feafa54d1d195

src/igl/vulkan/VulkanContext.cpp

@@ -1677,8 +1677,7 @@ void VulkanContext::updateBindingsBuffers(VkCommandBuffer IGL_NONNULL cmdBuf,
 
 void VulkanContext::deferredTask(std::packaged_task<void()>&& task, SubmitHandle handle) const {
   if (handle.empty()) {
-    handle = immediate_->currentCmdBufWrapper_ ? immediate_->currentCmdBufWrapper_->handle_
-                                               : immediate_->getLastSubmitHandle();
+    handle = immediate_->getNextSubmitHandle();
   }
   deferredTasks_.emplace_back(std::move(task), handle);
   deferredTasks_.back().frameId_ = this->getFrameNumber();

src/igl/vulkan/VulkanImmediateCommands.cpp

@@ -76,11 +76,11 @@ void VulkanImmediateCommands::purge() {
 
 const VulkanImmediateCommands::CommandBufferWrapper& VulkanImmediateCommands::acquire() {
   IGL_PROFILER_FUNCTION();
-  IGL_ASSERT_MSG(!currentCmdBufWrapper_,
+  IGL_ASSERT_MSG(nextSubmitHandle_.empty(),
                  "VulkanImmediateCommands::acquire() is not reentrant. You should submit() the "
                  "previous buffer before calling acquire() again.");
 
-  if (IGL_UNEXPECTED(currentCmdBufWrapper_)) {
+  if (IGL_UNEXPECTED(!nextSubmitHandle_.empty())) {
     IGL_LOG_ERROR(
         "VulkanImmediateCommands::acquire() is not reentrant. You should submit() the "
         "previous buffer before calling acquire() again.");
@@ -121,7 +121,7 @@ const VulkanImmediateCommands::CommandBufferWrapper& VulkanImmediateCommands::ac
   current->isEncoding_ = true;
   VK_ASSERT(ivkBeginCommandBuffer(&vf_, current->cmdBuf_));
 
-  currentCmdBufWrapper_ = current;
+  nextSubmitHandle_ = current->handle_;
   return *current;
 }
 
@@ -212,8 +212,6 @@ bool VulkanImmediateCommands::isReady(const SubmitHandle handle) const {
 VulkanImmediateCommands::SubmitHandle VulkanImmediateCommands::submit(
     const CommandBufferWrapper& wrapper) {
   IGL_PROFILER_FUNCTION_COLOR(IGL_PROFILER_COLOR_SUBMIT);
-  IGL_ASSERT(wrapper.cmdBuf_ == currentCmdBufWrapper_->cmdBuf_ &&
-             wrapper.handle_.handle() == currentCmdBufWrapper_->handle_.handle());
   IGL_ASSERT(wrapper.isEncoding_);
   VK_ASSERT(ivkEndCommandBuffer(&vf_, wrapper.cmdBuf_));
 
@@ -257,7 +255,7 @@ VulkanImmediateCommands::SubmitHandle VulkanImmediateCommands::submit(
     submitCounter_++;
   }
 
-  currentCmdBufWrapper_ = nullptr;
+  nextSubmitHandle_ = {};
 
   return lastSubmitHandle_;
 }
@@ -276,6 +274,10 @@ VulkanImmediateCommands::SubmitHandle VulkanImmediateCommands::getLastSubmitHand
   return lastSubmitHandle_;
 }
 
+VulkanImmediateCommands::SubmitHandle VulkanImmediateCommands::getNextSubmitHandle() const {
+  return nextSubmitHandle_.empty() ? lastSubmitHandle_ : nextSubmitHandle_;
+}
+
 VkFence VulkanImmediateCommands::getVkFenceFromSubmitHandle(SubmitHandle handle) {
   IGL_ASSERT(handle.bufferIndex_ < buffers_.size());
 

src/igl/vulkan/VulkanImmediateCommands.h

@@ -134,6 +134,7 @@ class VulkanImmediateCommands final {
 
   /// @brief Returns the last SubmitHandle, which was submitted when `submit()` was last called
   [[nodiscard]] SubmitHandle getLastSubmitHandle() const;
+  [[nodiscard]] SubmitHandle getNextSubmitHandle() const;
 
   /** @brief Checks whether a SubmitHandle is ready. A SubmitHandle is ready if it is recycled or
    * empty. If it has not been recycled and is not empty, a SubmitHandle is ready if the fence
@@ -156,8 +157,6 @@ class VulkanImmediateCommands final {
   /// Returns `VK_NULL_HANDLE` otherwise.
   VkFence getVkFenceFromSubmitHandle(SubmitHandle handle);
 
-  VulkanImmediateCommands::CommandBufferWrapper* currentCmdBufWrapper_ = nullptr;
-
  private:
   /// @brief Resets all commands buffers and their associated fences that are valid, are not being
   /// encoded, and have completed execution by the GPU (their fences have been signaled). Resets the
@@ -178,6 +177,7 @@ class VulkanImmediateCommands final {
 
   /// @brief The last submitted handle. Updated on `submit()`
   SubmitHandle lastSubmitHandle_ = SubmitHandle();
+  SubmitHandle nextSubmitHandle_ = SubmitHandle();
 
   /// @brief The semaphore submitted with the last command buffer. Updated on `submit()`
   VkSemaphore lastSubmitSemaphore_ = VK_NULL_HANDLE;