Internal changes only.

litert/c/BUILD

@@ -358,6 +358,7 @@ cc_library(
         "//litert/cc:litert_expected",
         "//litert/cc:litert_macros",
         "//litert/runtime:tensor_buffer",
+        "//litert/runtime:tensor_buffer_registry",
         "@com_google_absl//absl/types:span",
         "@opencl_headers",
     ] + gles_deps(),

litert/c/internal/litert_tensor_buffer_registry.cc

@@ -25,15 +25,16 @@ LiteRtStatus LiteRtRegisterTensorBufferHandlers(
     LiteRtEnvironment env, LiteRtTensorBufferType buffer_type,
     CreateCustomTensorBuffer create_func,
     DestroyCustomTensorBuffer destroy_func, LockCustomTensorBuffer lock_func,
-    UnlockCustomTensorBuffer unlock_func,
-    ImportCustomTensorBuffer import_func) {
+    UnlockCustomTensorBuffer unlock_func, ImportCustomTensorBuffer import_func,
+    GetCustomTensorBufferHandle get_handle_func) {
   auto& registry = env->GetTensorBufferRegistry();
   litert::internal::CustomTensorBufferHandlers handlers = {
       .create_func = create_func,
       .destroy_func = destroy_func,
       .lock_func = lock_func,
       .unlock_func = unlock_func,
       .import_func = import_func,
+      .get_handle_func = get_handle_func,
   };
   LITERT_RETURN_IF_ERROR(registry.RegisterHandlers(buffer_type, handlers));
   return kLiteRtStatusOk;

litert/c/internal/litert_tensor_buffer_registry.h

@@ -30,7 +30,9 @@ LiteRtStatus LiteRtRegisterTensorBufferHandlers(
     LiteRtEnvironment env, LiteRtTensorBufferType buffer_type,
     CreateCustomTensorBuffer create_func,
     DestroyCustomTensorBuffer destroy_func, LockCustomTensorBuffer lock_func,
-    UnlockCustomTensorBuffer unlock_func, ImportCustomTensorBuffer import_func);
+    UnlockCustomTensorBuffer unlock_func,
+    ImportCustomTensorBuffer import_func = nullptr,
+    GetCustomTensorBufferHandle get_handle_func = nullptr);
 
 // Retrieves a singleton instance of the tensor buffer registry.
 LiteRtStatus LiteRtGetTensorBufferRegistry(LiteRtEnvironment env,

litert/c/litert_custom_tensor_buffer.h

@@ -75,6 +75,10 @@ typedef LiteRtStatus (*LockCustomTensorBuffer)(LiteRtEnvironment env,
 typedef LiteRtStatus (*UnlockCustomTensorBuffer)(
     LiteRtEnvironment env, HwMemoryInfoPtr hw_memory_info);
 
+// Get the custom H/W memory buffer handle from HwMemoryInfoPtr.
+typedef LiteRtStatus (*GetCustomTensorBufferHandle)(
+    HwMemoryInfoPtr hw_memory_info, HwMemoryHandle* hw_memory_handle);
+
 #ifdef __cplusplus
 }
 #endif  // __cplusplus

litert/c/litert_tensor_buffer.cc

@@ -26,9 +26,9 @@
 #include "litert/cc/litert_macros.h"
 #include "litert/runtime/custom_buffer.h"
 #include "litert/runtime/tensor_buffer.h"
+#include "litert/runtime/tensor_buffer_registry.h"  // IWYU pragma: keep
 #include "litert/runtime/tensor_buffer_requirements.h"
 
-
 #if LITERT_HAS_OPENCL_SUPPORT
 #include <CL/cl.h>
 #endif  // LITERT_HAS_OPENCL_SUPPORT
@@ -202,8 +202,15 @@ LiteRtStatus LiteRtGetTensorBufferMetalMemory(
   LITERT_ASSIGN_OR_RETURN(litert::internal::CustomBuffer * custom_buffer,
                           tensor_buffer->GetCustomBuffer());
 
-  *hw_memory_handle = custom_buffer->hw_buffer_handle();
-  return kLiteRtStatusOk;
+  auto* registry = reinterpret_cast<litert::internal::TensorBufferRegistry*>(
+      tensor_buffer->GetTensorBufferRegistry());
+  LITERT_ASSIGN_OR_RETURN(
+      auto handlers, registry->GetCustomHandlers(tensor_buffer->buffer_type()));
+  if (handlers.get_handle_func) {
+    return handlers.get_handle_func(custom_buffer->hw_memory_info(),
+                                    hw_memory_handle);
+  }
+  return kLiteRtStatusErrorUnsupported;
 }
 
 #endif  // LITERT_HAS_METAL_SUPPORT

litert/cc/BUILD

@@ -1052,6 +1052,7 @@ cc_library(
 #         ":litert_macros",
 #         ":litert_model",
 #         ":litert_tensor_buffer",
+#         "@com_google_absl//absl/log:absl_log",
 #         "//third_party/apple_frameworks:XCTest",
 #         "//litert/c:litert_common",
 #         "//litert/c:litert_environment",

litert/cc/litert_tensor_buffer_test.mm

@@ -15,6 +15,7 @@
 #import "third_party/odml/litert/litert/cc/litert_tensor_buffer.h"
 #import <XCTest/XCTest.h>
 #import <XCTest/XCTestAssertions.h>
+#include "absl/log/absl_log.h"  // from @com_google_absl
 #include "litert/c/litert_common.h"
 #include "litert/c/litert_environment.h"
 #include "litert/c/litert_model_types.h"
@@ -127,6 +128,7 @@ - (void)testTensorBufferCreateFromMetalMemory {
   XCTAssertTrue(metal_buffer);
 
   // Create a tensor buffer from the existing metal buffer.
+  ABSL_LOG(INFO) << "Before create from metal buffer";
   auto metal_buffer_created = litert::TensorBuffer::CreateFromMetalBuffer(
       *env, kTensorType, kTensorBufferType, *metal_buffer, sizeof(kTensorData));
   XCTAssertTrue(metal_buffer_created);

litert/runtime/custom_buffer.h

@@ -46,6 +46,7 @@ class CustomBuffer {
   ~CustomBuffer();
 
   HwMemoryHandle hw_buffer_handle() { return hw_memory_info_->memory_handle; }
+  HwMemoryInfoPtr hw_memory_info() { return hw_memory_info_; }
   // Allocates a CPU memory and conducts a copy from the Custom buffer to the
   // CPU memory.
   Expected<void*> Lock(LiteRtTensorBufferLockMode mode);

litert/runtime/tensor_buffer.cc

@@ -27,6 +27,7 @@
 #include "absl/strings/str_format.h"  // from @com_google_absl
 #include "absl/types/span.h"  // from @com_google_absl
 #include "litert/c/internal/litert_logging.h"
+#include "litert/c/internal/litert_tensor_buffer_registry.h"
 #include "litert/c/litert_common.h"
 #include "litert/c/litert_model_types.h"
 #include "litert/c/litert_tensor_buffer_types.h"
@@ -1003,6 +1004,12 @@ Expected<void*> LiteRtTensorBufferT::Lock(LiteRtTensorBufferLockMode mode) {
   }
 }
 
+void* LiteRtTensorBufferT::GetTensorBufferRegistry() {
+  void* registry = nullptr;
+  LiteRtGetTensorBufferRegistry(env_, &registry);
+  return registry;
+}
+
 Expected<void> LiteRtTensorBufferT::Unlock() {
   LITERT_RETURN_IF_ERROR(is_locked_ == true,
                          Unexpected(kLiteRtStatusErrorRuntimeFailure,

litert/runtime/tensor_buffer.h

@@ -187,6 +187,8 @@ class LiteRtTensorBufferT {
   // Gets the current reference count.
   int RefCount() const { return ref_.load(std::memory_order_relaxed); }
 
+  void* GetTensorBufferRegistry();
+
  private:
   struct HostBuffer {
     void* addr;

litert/runtime/tensor_buffer_registry.h

@@ -32,6 +32,7 @@ struct CustomTensorBufferHandlers {
   // Optional function to import an existing buffer.
   // TODO(b/446717438): Merge this with the create function.
   ::ImportCustomTensorBuffer import_func;
+  ::GetCustomTensorBufferHandle get_handle_func;
 };
 
 class TensorBufferRegistry {