Benchmarking: Add pov_mode to V2 syntax (#3616)

Changes:
- Port the `pov_mode` attribute from the V1 syntax to V2
- Update `pallet-whitelist` and `frame-benchmarking-pallet-pov`

Follow up: also allow this attribute on top-level benchmark modules.

---------

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
Co-authored-by: command-bot <>

substrate/frame/support/test/tests/benchmark_ui/pass/valid_attr_pov_mode.rs

@@ -0,0 +1,74 @@
+// This file is part of Substrate.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use frame_benchmarking::v2::*;
+use frame_support_test::Config;
+
+#[benchmarks]
+mod benches {
+	use super::*;
+
+	#[benchmark(skip_meta, extra, pov_mode = Measured)]
+	fn bench1() {
+		#[block]
+		{}
+	}
+
+	#[benchmark(pov_mode = Measured, extra, skip_meta)]
+	fn bench2() {
+		#[block]
+		{}
+	}
+
+	#[benchmark(extra, pov_mode = Measured {
+		Pallet: Measured,
+		Pallet::Storage: MaxEncodedLen,
+	}, skip_meta)]
+	fn bench3() {
+		#[block]
+		{}
+	}
+
+	#[benchmark(skip_meta, extra, pov_mode = Measured {
+		Pallet::Storage: MaxEncodedLen,
+		Pallet::StorageSubKey: Measured,
+	})]
+	fn bench4() {
+		#[block]
+		{}
+	}
+
+	#[benchmark(pov_mode = MaxEncodedLen {
+		Pallet::Storage: Measured,
+		Pallet::StorageSubKey: Measured
+	}, extra, skip_meta)]
+	fn bench5() {
+		#[block]
+		{}
+	}
+
+	#[benchmark(pov_mode = MaxEncodedLen {
+		Pallet::Storage: Measured,
+		Pallet::Storage::Nested: Ignored
+	}, extra, skip_meta)]
+	fn bench6() {
+		#[block]
+		{}
+	}
+}
+
+fn main() {}

substrate/frame/support/test/tests/benchmark_ui/pass/valid_basic.rs

@@ -22,7 +22,7 @@ use frame_support_test::Config;
 mod benches {
 	use super::*;
 
-	#[benchmark(skip_meta, extra)]
+	#[benchmark(skip_meta, pov_mode = Measured, extra)]
 	fn bench() {
 		let a = 2 + 2;
 		#[block]