Consolidate frame benchmarking into a frame crate (#4977)

This prs cleans up some of the frame benchmarking stuff:
- Move CLI into `frame-benchmarking-cli`. No frame related CLI should
exists in the default Substrate CLI.
- Move all traits and types related to frame benchmarking into the
`frame-benchmarking` trait. Frame types should be isolated in Frame.

substrate/frame/benchmarking/src/lib.rs

@@ -0,0 +1,141 @@
+// Copyright 2020 Parity Technologies (UK) Ltd.
+// This file is part of Substrate.
+
+// Substrate is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Substrate is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Interfaces and types for benchmarking a FRAME runtime.
+
+#![cfg_attr(not(feature = "std"), no_std)]
+
+use sp_std::vec::Vec;
+
+/// An alphabet of possible parameters to use for benchmarking.
+#[derive(codec::Encode, codec::Decode, Clone, Copy, PartialEq, Debug)]
+#[allow(missing_docs)]
+pub enum BenchmarkParameter {
+	A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z,
+}
+
+/// Results from running benchmarks on a FRAME pallet.
+/// Contains duration of the function call in nanoseconds along with the benchmark parameters
+/// used for that benchmark result.
+pub type BenchmarkResults = (Vec<(BenchmarkParameter, u32)>, u128);
+
+sp_api::decl_runtime_apis! {
+	/// Runtime api for benchmarking a FRAME runtime.
+	pub trait Benchmark {
+		/// Dispatch the given benchmark.
+		fn dispatch_benchmark(
+			module: Vec<u8>,
+			extrinsic: Vec<u8>,
+			steps: u32,
+			repeat: u32,
+		) -> Option<Vec<BenchmarkResults>>;
+	}
+}
+
+/// Interface that provides functions for benchmarking the runtime.
+#[sp_runtime_interface::runtime_interface]
+pub trait Benchmarking {
+	/// Get the number of nanoseconds passed since the UNIX epoch
+	///
+	/// WARNING! This is a non-deterministic call. Do not use this within
+	/// consensus critical logic.
+	fn current_time() -> u128 {
+		std::time::SystemTime::now().duration_since(std::time::SystemTime::UNIX_EPOCH)
+			.expect("Unix time doesn't go backwards; qed")
+			.as_nanos()
+	}
+
+	/// Reset the trie database to the genesis state.
+	fn wipe_db(&mut self) {
+		self.wipe()
+	}
+
+	/// Commit pending storage changes to the trie database and clear the database cache.
+	fn commit_db(&mut self) {
+		self.commit()
+	}
+}
+
+/// The pallet benchmarking trait.
+pub trait Benchmarking<T> {
+	/// Run the benchmarks for this pallet.
+	///
+	/// Parameters
+	/// - `extrinsic`: The name of extrinsic function you want to benchmark encoded as bytes.
+	/// - `steps`: The number of sample points you want to take across the range of parameters.
+	/// - `repeat`: The number of times you want to repeat a benchmark.
+	fn run_benchmark(extrinsic: Vec<u8>, steps: u32, repeat: u32) -> Result<Vec<T>, &'static str>;
+}
+
+/// The required setup for creating a benchmark.
+pub trait BenchmarkingSetup<T, Call, RawOrigin> {
+	/// Return the components and their ranges which should be tested in this benchmark.
+	fn components(&self) -> Vec<(BenchmarkParameter, u32, u32)>;
+
+	/// Set up the storage, and prepare a call and caller to test in a single run of the benchmark.
+	fn instance(&self, components: &[(BenchmarkParameter, u32)]) -> Result<(Call, RawOrigin), &'static str>;
+}
+
+/// Creates a `SelectedBenchmark` enum implementing `BenchmarkingSetup`.
+///
+/// Every variant must implement [`BenchmarkingSetup`].
+///
+/// ```nocompile
+///
+/// struct Transfer;
+/// impl BenchmarkingSetup for Transfer { ... }
+///
+/// struct SetBalance;
+/// impl BenchmarkingSetup for SetBalance { ... }
+///
+/// selected_benchmark!(Transfer, SetBalance);
+/// ```
+#[macro_export]
+macro_rules! selected_benchmark {
+	(
+		$( $bench:ident ),*
+	) => {
+		// The list of available benchmarks for this pallet.
+		enum SelectedBenchmark {
+			$( $bench, )*
+		}
+
+		// Allow us to select a benchmark from the list of available benchmarks.
+		impl<T: Trait> $crate::BenchmarkingSetup<T, Call<T>, RawOrigin<T::AccountId>> for SelectedBenchmark {
+			fn components(&self) -> Vec<($crate::BenchmarkParameter, u32, u32)> {
+				match self {
+					$( Self::$bench => <$bench as $crate::BenchmarkingSetup<
+						T,
+						Call<T>,
+						RawOrigin<T::AccountId>,
+					>>::components(&$bench), )*
+				}
+			}
+
+			fn instance(&self, components: &[($crate::BenchmarkParameter, u32)])
+				-> Result<(Call<T>, RawOrigin<T::AccountId>), &'static str>
+			{
+				match self {
+					$( Self::$bench => <$bench as $crate::BenchmarkingSetup<
+						T,
+						Call<T>,
+						RawOrigin<T::AccountId>,
+					>>::instance(&$bench, components), )*
+				}
+			}
+		}
+	};
+}