[3/N] Add get_option/set_option function in backend interface

runtime/backend/backend_options.h

@@ -6,88 +6,94 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-#pragma once
-#include <executorch/runtime/core/error.h>
-#include <cstddef>
-#include <cstring>
-#include <variant>
-
-namespace executorch {
-namespace runtime {
-
-// Strongly-typed option key template
-template <typename T>
-struct OptionKey {
-  const char* key;
-  constexpr explicit OptionKey(const char* k) : key(k) {}
-};
-
-// Union replaced with std::variant
-using OptionValue = std::variant<bool, int, const char*>;
-
-struct BackendOption {
-  const char* key; // key is the name of the backend option, like num_threads,
-                   // enable_profiling, etc
-  OptionValue
-      value; // value is the value of the backend option, like 4, true, etc
-};
-
-template <size_t MaxCapacity>
-class BackendOptions {
- public:
-  // Initialize with zero options
-  BackendOptions() : size_(0) {}
-
-  // Type-safe setters
-  template <typename T>
-  void set_option(OptionKey<T> key, T value) {
-    const char* k = key.key;
-    // Update existing if found
-    for (size_t i = 0; i < size_; ++i) {
-      if (strcmp(options_[i].key, k) == 0) {
-        options_[i].value = value;
-        return;
-      }
-    }
-    // Add new option if space available
-    if (size_ < MaxCapacity) {
-      options_[size_++] = BackendOption{k, value};
-    }
-  }
-
-  // Type-safe getters
-  template <typename T>
-  Error get_option(OptionKey<T> key, T& out) const {
-    const char* k = key.key;
-    for (size_t i = 0; i < size_; ++i) {
-      if (strcmp(options_[i].key, k) == 0) {
-        if (auto* val = std::get_if<T>(&options_[i].value)) {
-          out = *val;
-          return Error::Ok;
-        }
-        return Error::InvalidArgument;
-      }
-    }
-    return Error::NotFound;
-  }
-
- private:
-  BackendOption options_[MaxCapacity]{}; // Storage for backend options
-  size_t size_; // Current number of options
-};
-
-// Helper functions for creating typed option keys (unchanged)
-constexpr OptionKey<bool> BoolKey(const char* k) {
-  return OptionKey<bool>(k);
-}
-
-constexpr OptionKey<int> IntKey(const char* k) {
-  return OptionKey<int>(k);
-}
-
-constexpr OptionKey<const char*> StrKey(const char* k) {
-  return OptionKey<const char*>(k);
-}
-
-} // namespace runtime
-} // namespace executorch
+ #pragma once
+ #include <executorch/runtime/core/error.h>
+ #include <cstddef>
+ #include <cstring>
+ #include <executorch/runtime/core/array_ref.h>
+ #include <executorch/runtime/core/error.h>
+ #include <variant>
+
+ namespace executorch {
+ namespace runtime {
+
+ // Strongly-typed option key template
+ template <typename T>
+ struct OptionKey {
+   const char* key;
+   constexpr explicit OptionKey(const char* k) : key(k) {}
+ };
+
+ // Union replaced with std::variant
+ using OptionValue = std::variant<bool, int, const char*>;
+
+ struct BackendOption {
+   const char* key; // key is the name of the backend option, like num_threads,
+                    // enable_profiling, etc
+   OptionValue
+       value; // value is the value of the backend option, like 4, true, etc
+ };
+
+ template <size_t MaxCapacity>
+ class BackendOptions {
+  public:
+   // Initialize with zero options
+   BackendOptions() : size_(0) {}
+
+   // Type-safe setters
+   template <typename T>
+   void set_option(OptionKey<T> key, T value) {
+     const char* k = key.key;
+     // Update existing if found
+     for (size_t i = 0; i < size_; ++i) {
+       if (strcmp(options_[i].key, k) == 0) {
+         options_[i].value = value;
+         return;
+       }
+     }
+     // Add new option if space available
+     if (size_ < MaxCapacity) {
+       options_[size_++] = BackendOption{k, value};
+     }
+   }
+
+   // Type-safe getters
+   template <typename T>
+   Error get_option(OptionKey<T> key, T& out) const {
+     const char* k = key.key;
+     for (size_t i = 0; i < size_; ++i) {
+       if (strcmp(options_[i].key, k) == 0) {
+         if (auto* val = std::get_if<T>(&options_[i].value)) {
+           out = *val;
+           return Error::Ok;
+         }
+         return Error::InvalidArgument;
+       }
+     }
+     return Error::NotFound;
+   }
+   executorch::runtime::ArrayRef<BackendOption> view() const {
+     return executorch::runtime::ArrayRef<BackendOption>(options_, size_);
+   }
+
+  private:
+   BackendOption options_[MaxCapacity]{}; // Storage for backend options
+   size_t size_; // Current number of options
+ };
+
+ // Helper functions for creating typed option keys (unchanged)
+ constexpr OptionKey<bool> BoolKey(const char* k) {
+   return OptionKey<bool>(k);
+ }
+
+ constexpr OptionKey<int> IntKey(const char* k) {
+   return OptionKey<int>(k);
+ }
+
+ constexpr OptionKey<const char*> StrKey(const char* k) {
+   return OptionKey<const char*>(k);
+ }
+
+ } // namespace runtime
+ } // namespace executorch
+

runtime/backend/interface.h

@@ -12,6 +12,8 @@
 
 #include <executorch/runtime/backend/backend_execution_context.h>
 #include <executorch/runtime/backend/backend_init_context.h>
+#include <executorch/runtime/backend/backend_update_context.h>
+#include <executorch/runtime/backend/backend_options.h>
 #include <executorch/runtime/core/array_ref.h>
 #include <executorch/runtime/core/error.h>
 #include <executorch/runtime/core/evalue.h>
@@ -99,6 +101,20 @@ class BackendInterface {
       DelegateHandle* handle,
       EValue** args) const = 0;
 
+  /**
+   * Responsible update the backend status, if any. The backend options are passed in
+   * by users, and the backend can update its internal status based on the options.
+   *
+   * @param[in] context Runtime context if any. Currently it's not used.
+   * @param[in] args A list of BackendOptions passed in by users.
+   * @retval Error::Ok if successful.
+   */
+   ET_NODISCARD virtual Error update(
+    BackendUpdateContext& context,
+    const executorch::runtime::ArrayRef<BackendOption>& backend_options) const {
+        return Error::Ok;
+      };
+
   /**
    * Responsible for destroying a handle, if it's required for some backend.
    * It may be needed for some backends. For example, resources associated with