Add RAII safeguard: ComputeEncoder destructors call endEncoding()

Makes CommandEncoder::endEncoding() idempotent (split into a non-virtual wrapper plus a protected virtual endEncodingImpl()), then has each backend's ComputeEncoder destructor call endEncoding() so an encoder destroyed without an explicit end still flushes pending barriers and pops its debug group.

Author: MarijnS95

include/API/Encoder.h

@@ -35,6 +35,12 @@ enum class EncoderMode {
 class CommandEncoder {
   GPUAPI API;
   EncoderMode Mode;
+  bool Ended = false;
+
+protected:
+  /// Backend-specific cleanup. Called exactly once, either explicitly via
+  /// endEncoding() or implicitly from the most-derived destructor.
+  virtual void endEncodingImpl() = 0;
 
 public:
   CommandEncoder(GPUAPI API, EncoderMode Mode) : API(API), Mode(Mode) {}
@@ -45,6 +51,7 @@ class CommandEncoder {
   GPUAPI getAPI() const { return API; }
   EncoderMode getMode() const { return Mode; }
   bool isSerial() const { return Mode == EncoderMode::Serial; }
+  bool isEnded() const { return Ended; }
 
   /// Copy \p Size bytes from \p Src at \p SrcOffset to \p Dst at
   /// \p DstOffset.
@@ -68,7 +75,15 @@ class CommandEncoder {
   virtual void insertDebugSignpost(llvm::StringRef Label) {}
 
   /// Finish recording. No further commands may be recorded after this call.
-  virtual void endEncoding() = 0;
+  /// Idempotent: safe to call more than once. If not called explicitly, the
+  /// most-derived destructor invokes it as a safeguard against leaked open
+  /// encoders.
+  void endEncoding() {
+    if (Ended)
+      return;
+    endEncodingImpl();
+    Ended = true;
+  }
 };
 
 /// Encoder for recording compute dispatch commands.

lib/API/DX/Device.cpp

@@ -551,7 +551,7 @@ class DXComputeEncoder : public offloadtest::ComputeEncoder {
   DXComputeEncoder(DXCommandBuffer &CB, EncoderMode Mode)
       : ComputeEncoder(GPUAPI::DirectX, Mode), CB(CB) {}
 
-  ~DXComputeEncoder() override = default;
+  ~DXComputeEncoder() override { endEncoding(); }
 
   void pushDebugGroup(llvm::StringRef Label) override {
     CB.CmdList->BeginEvent(0, Label.data(), Label.size() + 1);
@@ -617,7 +617,7 @@ class DXComputeEncoder : public offloadtest::ComputeEncoder {
     CB.flushBarrier();
   }
 
-  void endEncoding() override { popDebugGroup(); }
+  void endEncodingImpl() override { popDebugGroup(); }
 };
 
 llvm::Expected<std::unique_ptr<offloadtest::ComputeEncoder>>

lib/API/MTL/MTLDevice.cpp

@@ -14,7 +14,6 @@
 #include "MTLResources.h"
 #include "Support/Pipeline.h"
 
-#include "llvm/ADT/ScopeExit.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/FormatVariadic.h"
@@ -264,7 +263,7 @@ class MTLComputeEncoder : public offloadtest::ComputeEncoder {
       : ComputeEncoder(GPUAPI::Metal, Mode), CmdBuffer(CmdBuffer),
         ComputeEnc(Encoder) {}
 
-  ~MTLComputeEncoder() override = default;
+  ~MTLComputeEncoder() override { endEncoding(); }
 
   MTL::ComputeCommandEncoder *getNative() const { return ComputeEnc; }
 
@@ -361,7 +360,7 @@ class MTLComputeEncoder : public offloadtest::ComputeEncoder {
     }
   }
 
-  void endEncoding() override {
+  void endEncodingImpl() override {
     if (ComputeEnc) {
       barrier();
       ComputeEnc->popDebugGroup();

lib/API/VK/Device.cpp

@@ -653,7 +653,7 @@ class VKComputeEncoder : public offloadtest::ComputeEncoder {
   VKComputeEncoder(VulkanCommandBuffer &CB, EncoderMode Mode)
       : ComputeEncoder(GPUAPI::Vulkan, Mode), CB(CB) {}
 
-  ~VKComputeEncoder() override = default;
+  ~VKComputeEncoder() override { endEncoding(); }
 
   void pushDebugGroup(llvm::StringRef Label) override {
     if (!CB.CmdBeginDebugUtilsLabel)
@@ -745,7 +745,7 @@ class VKComputeEncoder : public offloadtest::ComputeEncoder {
                     VK_ACCESS_SHADER_WRITE_BIT | VK_ACCESS_SHADER_READ_BIT);
   }
 
-  void endEncoding() override { popDebugGroup(); }
+  void endEncodingImpl() override { popDebugGroup(); }
 };
 
 llvm::Expected<std::unique_ptr<offloadtest::ComputeEncoder>>