diff --git a/Cargo.lock b/Cargo.lock
index 0da61066df86a..9eb942aae82bb 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -136,7 +136,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "autocfg 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "backtrace-sys 0.1.28 (registry+https://github.com/rust-lang/crates.io-index)",
- "cfg-if 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cfg-if 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.48 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-demangle 0.1.13 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -194,7 +194,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "cexpr 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "cfg-if 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cfg-if 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "clang-sys 0.26.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "clap 2.32.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "env_logger 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -330,7 +330,7 @@ dependencies = [
 
 [[package]]
 name = "cfg-if"
-version = "0.1.6"
+version = "0.1.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -453,7 +453,7 @@ name = "crossbeam"
 version = "0.6.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "cfg-if 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cfg-if 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "crossbeam-channel 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "crossbeam-deque 0.6.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "crossbeam-epoch 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -496,7 +496,7 @@ version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "arrayvec 0.4.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "cfg-if 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cfg-if 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "crossbeam-utils 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "memoffset 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -510,7 +510,7 @@ version = "0.7.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "arrayvec 0.4.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "cfg-if 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cfg-if 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "crossbeam-utils 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "memoffset 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -522,7 +522,7 @@ name = "crossbeam-utils"
 version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "cfg-if 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cfg-if 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -530,7 +530,7 @@ name = "crossbeam-utils"
 version = "0.6.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "cfg-if 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cfg-if 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -1675,7 +1675,7 @@ name = "log"
 version = "0.4.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "cfg-if 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cfg-if 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1701,7 +1701,7 @@ name = "memchr"
 version = "2.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "cfg-if 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cfg-if 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.48 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -1838,7 +1838,7 @@ name = "net2"
 version = "0.2.33"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "cfg-if 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cfg-if 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.48 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -1850,7 +1850,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "cc 1.0.26 (registry+https://github.com/rust-lang/crates.io-index)",
- "cfg-if 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cfg-if 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.48 (registry+https://github.com/rust-lang/crates.io-index)",
  "void 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -2095,7 +2095,7 @@ version = "0.10.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "cfg-if 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cfg-if 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "foreign-types 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.48 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -4176,7 +4176,7 @@ dependencies = [
 name = "substrate-test-runtime"
 version = "0.1.0"
 dependencies = [
- "cfg-if 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cfg-if 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "hex-literal 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "parity-codec 3.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -4186,6 +4186,7 @@ dependencies = [
  "sr-primitives 0.1.0",
  "sr-std 0.1.0",
  "sr-version 0.1.0",
+ "srml-executive 0.1.0",
  "srml-support 0.1.0",
  "substrate-client 0.1.0",
  "substrate-consensus-aura-primitives 0.1.0",
@@ -4282,7 +4283,7 @@ name = "sysinfo"
 version = "0.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "cfg-if 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cfg-if 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.48 (registry+https://github.com/rust-lang/crates.io-index)",
  "rayon 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -4312,7 +4313,7 @@ name = "tempfile"
 version = "3.0.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "cfg-if 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cfg-if 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.48 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "redox_syscall 0.1.51 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -5034,7 +5035,7 @@ dependencies = [
 "checksum cast 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "926013f2860c46252efceabb19f4a6b308197505082c609025aa6706c011d427"
 "checksum cc 1.0.26 (registry+https://github.com/rust-lang/crates.io-index)" = "389803e36973d242e7fecb092b2de44a3d35ac62524b3b9339e51d577d668e02"
 "checksum cexpr 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)" = "644d693ecfa91955ed32dcc7eda4914e1be97a641fb6f0645a37348e20b230da"
-"checksum cfg-if 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)" = "082bb9b28e00d3c9d39cc03e64ce4cea0f1bb9b3fde493f0cbc008472d22bdf4"
+"checksum cfg-if 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)" = "11d43355396e872eefb45ce6342e4374ed7bc2b3a502d1b28e36d6e23c05d1f4"
 "checksum chrono 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)" = "45912881121cb26fad7c38c17ba7daa18764771836b34fab7d3fbd93ed633878"
 "checksum clang-sys 0.26.4 (registry+https://github.com/rust-lang/crates.io-index)" = "6ef0c1bcf2e99c649104bd7a7012d8f8802684400e03db0ec0af48583c6fa0e4"
 "checksum clap 2.32.0 (registry+https://github.com/rust-lang/crates.io-index)" = "b957d88f4b6a63b9d70d5f454ac8011819c6efa7727858f458ab71c756ce2d3e"
diff --git a/core/executor/src/wasm_executor.rs b/core/executor/src/wasm_executor.rs
index 7e459826989d4..7e6833bb7839f 100644
--- a/core/executor/src/wasm_executor.rs
+++ b/core/executor/src/wasm_executor.rs
@@ -23,7 +23,7 @@ use secp256k1;
 use wasmi::{
 	Module, ModuleInstance, MemoryInstance, MemoryRef, TableRef, ImportsBuilder, ModuleRef,
 };
-use wasmi::RuntimeValue::{I32, I64};
+use wasmi::RuntimeValue::{I32, I64, self};
 use wasmi::memory_units::{Pages};
 use state_machine::Externalities;
 use crate::error::{Error, ErrorKind, Result};
@@ -393,10 +393,12 @@ impl_function_executor!(this: FunctionExecutor<'e, E>,
 			.map_err(|_| UserError("Invalid attempt to get parent_hash in ext_storage_changes_root"))?;
 		parent_hash.as_mut().copy_from_slice(&raw_parent_hash[..]);
 		let r = this.ext.storage_changes_root(parent_hash, parent_number);
-		if let Some(ref r) = r {
+		if let Some(r) = r {
 			this.memory.set(result, &r[..]).map_err(|_| UserError("Invalid attempt to set memory in ext_storage_changes_root"))?;
+			Ok(1)
+		} else {
+			Ok(0)
 		}
-		Ok(if r.is_some() { 1u32 } else { 0u32 })
 	},
 	ext_blake2_256_enumerated_trie_root(values_data: *const u8, lens_data: *const u32, lens_len: u32, result: *mut u8) => {
 		let values = (0..lens_len)
@@ -637,17 +639,19 @@ impl_function_executor!(this: FunctionExecutor<'e, E>,
 ///
 /// Executes the provided code in a sandboxed wasm runtime.
 #[derive(Debug, Clone)]
-pub struct WasmExecutor {
-}
+pub struct WasmExecutor;
 
 impl WasmExecutor {
 
 	/// Create a new instance.
 	pub fn new() -> Self {
-		WasmExecutor{}
+		WasmExecutor
 	}
 
 	/// Call a given method in the given code.
+	///
+	/// Signature of this method needs to be `(I32, I32) -> I64`.
+	///
 	/// This should be used for tests only.
 	pub fn call<E: Externalities<Blake2Hasher>>(
 		&self,
@@ -656,12 +660,34 @@ impl WasmExecutor {
 		code: &[u8],
 		method: &str,
 		data: &[u8],
-		) -> Result<Vec<u8>> {
+	) -> Result<Vec<u8>> {
 		let module = ::wasmi::Module::from_buffer(code)?;
 		let module = self.prepare_module(ext, heap_pages, &module)?;
 		self.call_in_wasm_module(ext, &module, method, data)
 	}
 
+	/// Call a given method with a custom signature in the given code.
+	///
+	/// This should be used for tests only.
+	pub fn call_with_custom_signature<
+		E: Externalities<Blake2Hasher>,
+		F: FnOnce(&mut FnMut(&[u8]) -> Result<u32>) -> Result<Vec<RuntimeValue>>,
+		FR: FnOnce(Option<RuntimeValue>, &MemoryRef) -> Result<Option<R>>,
+		R,
+	>(
+		&self,
+		ext: &mut E,
+		heap_pages: usize,
+		code: &[u8],
+		method: &str,
+		create_parameters: F,
+		filter_result: FR,
+	) -> Result<R> {
+		let module = wasmi::Module::from_buffer(code)?;
+		let module = self.prepare_module(ext, heap_pages, &module)?;
+		self.call_in_wasm_module_with_custom_signature(ext, &module, method, create_parameters, filter_result)
+	}
+
 	fn get_mem_instance(module: &ModuleRef) -> Result<MemoryRef> {
 		Ok(module
 			.export_by_name("memory")
@@ -679,6 +705,40 @@ impl WasmExecutor {
 		method: &str,
 		data: &[u8],
 	) -> Result<Vec<u8>> {
+		self.call_in_wasm_module_with_custom_signature(
+			ext,
+			module_instance,
+			method,
+			|alloc| {
+				let offset = alloc(data)?;
+				Ok(vec![I32(offset as i32), I32(data.len() as i32)])
+			},
+			|res, memory| {
+				if let Some(I64(r)) = res {
+					let offset = r as u32;
+					let length = (r as u64 >> 32) as usize;
+					memory.get(offset, length).map_err(|_| ErrorKind::Runtime.into()).map(Some)
+				} else {
+					Ok(None)
+				}
+			}
+		)
+	}
+
+	/// Call a given method in the given wasm-module runtime.
+	fn call_in_wasm_module_with_custom_signature<
+		E: Externalities<Blake2Hasher>,
+		F: FnOnce(&mut FnMut(&[u8]) -> Result<u32>) -> Result<Vec<RuntimeValue>>,
+		FR: FnOnce(Option<RuntimeValue>, &MemoryRef) -> Result<Option<R>>,
+		R,
+	>(
+		&self,
+		ext: &mut E,
+		module_instance: &ModuleRef,
+		method: &str,
+		create_parameters: F,
+		filter_result: FR,
+	) -> Result<R> {
 		// extract a reference to a linear memory, optional reference to a table
 		// and then initialize FunctionExecutor.
 		let memory = Self::get_mem_instance(module_instance)?;
@@ -689,26 +749,22 @@ impl WasmExecutor {
 		let low = memory.lowest_used();
 		let used_mem = memory.used_size();
 		let mut fec = FunctionExecutor::new(memory.clone(), table, ext)?;
-		let size = data.len() as u32;
-		let offset = fec.heap.allocate(size).map_err(|_| ErrorKind::Runtime)?;
-		memory.set(offset, &data)?;
+		let parameters = create_parameters(&mut |data: &[u8]| {
+			let offset = fec.heap.allocate(data.len() as u32).map_err(|_| ErrorKind::Runtime)?;
+			memory.set(offset, &data)?;
+			Ok(offset)
+		})?;
 
 		let result = module_instance.invoke_export(
 			method,
-			&[
-				I32(offset as i32),
-				I32(size as i32)
-			],
+			&parameters,
 			&mut fec
 		);
 		let result = match result {
-			Ok(Some(I64(r))) => {
-				let offset = r as u32;
-				let length = (r >> 32) as u32 as usize;
-				memory.get(offset, length)
-					.map_err(|_| ErrorKind::Runtime.into())
+			Ok(val) => match filter_result(val, &memory)? {
+				Some(val) => Ok(val),
+				None => Err(ErrorKind::InvalidReturn.into()),
 			},
-			Ok(_) => Err(ErrorKind::InvalidReturn.into()),
 			Err(e) => {
 				trace!(target: "wasm-executor", "Failed to execute code with {} pages", memory.current_size().0);
 				Err(e.into())
@@ -738,7 +794,7 @@ impl WasmExecutor {
 			module,
 			&ImportsBuilder::new()
 			.with_resolver("env", FunctionExecutor::<E>::resolver())
-			)?;
+		)?;
 
 		// extract a reference to a linear memory, optional reference to a table
 		// and then initialize FunctionExecutor.
@@ -759,7 +815,7 @@ impl WasmExecutor {
 #[cfg(test)]
 mod tests {
 	use super::*;
-	
+
 	use parity_codec::Encode;
 
 	use state_machine::TestExternalities;
diff --git a/core/sr-api-macros/benches/bench.rs b/core/sr-api-macros/benches/bench.rs
index 85ea3d6f88dd3..f467721789792 100644
--- a/core/sr-api-macros/benches/bench.rs
+++ b/core/sr-api-macros/benches/bench.rs
@@ -14,9 +14,10 @@
 // You should have received a copy of the GNU General Public License
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
 
-use criterion::Criterion;
+use criterion::{Criterion, criterion_group, criterion_main};
 use test_client::runtime::TestAPI;
 use runtime_primitives::{generic::BlockId, traits::ProvideRuntimeApi};
+use state_machine::ExecutionStrategy;
 
 fn sr_api_benchmark(c: &mut Criterion) {
 	c.bench_function("add one with same runtime api", |b| {
@@ -50,6 +51,18 @@ fn sr_api_benchmark(c: &mut Criterion) {
 
 		b.iter_with_large_drop(|| client.runtime_api().benchmark_vector_add_one(&block_id, &data))
 	});
+
+	c.bench_function("calling function by function pointer in wasm", |b| {
+		let client = test_client::new_with_execution_strategy(ExecutionStrategy::AlwaysWasm);
+		let block_id = BlockId::Number(client.info().unwrap().chain.best_number);
+		b.iter(|| client.runtime_api().benchmark_indirect_call(&block_id).unwrap())
+	});
+
+	c.bench_function("calling function in wasm", |b| {
+		let client = test_client::new_with_execution_strategy(ExecutionStrategy::AlwaysWasm);
+		let block_id = BlockId::Number(client.info().unwrap().chain.best_number);
+		b.iter(|| client.runtime_api().benchmark_direct_call(&block_id).unwrap())
+	});
 }
 
 criterion_group!(benches, sr_api_benchmark);
diff --git a/core/sr-io/Cargo.toml b/core/sr-io/Cargo.toml
index 01907832f8a25..fa04c17e3fd9a 100644
--- a/core/sr-io/Cargo.toml
+++ b/core/sr-io/Cargo.toml
@@ -35,3 +35,4 @@ std = [
 ]
 nightly = []
 strict = []
+wasm-nice-panic-message = []
\ No newline at end of file
diff --git a/core/sr-io/without_std.rs b/core/sr-io/without_std.rs
index 7763ddf04a1ac..41dc530d5694a 100644
--- a/core/sr-io/without_std.rs
+++ b/core/sr-io/without_std.rs
@@ -20,19 +20,27 @@ pub use parity_codec as codec;
 pub use rstd;
 pub use rstd::{mem, slice};
 
-use core::intrinsics;
-use rstd::vec::Vec;
+use core::{intrinsics, panic::PanicInfo};
+use rstd::{vec::Vec, cell::Cell};
 use hash_db::Hasher;
 use primitives::Blake2Hasher;
 
 #[panic_handler]
 #[no_mangle]
-pub fn panic(info: &::core::panic::PanicInfo) -> ! {
+pub fn panic(info: &PanicInfo) -> ! {
 	unsafe {
-		if let Some(loc) = info.location() {
-			ext_print_utf8(loc.file().as_ptr() as *const u8, loc.file().len() as u32);
-			ext_print_num(loc.line() as u64);
-			ext_print_num(loc.column() as u64);
+		#[cfg(feature = "wasm-nice-panic-message")]
+		{
+			let message = rstd::alloc::format!("{}", info);
+			extern_functions_host_impl::ext_print_utf8(message.as_ptr() as *const u8, message.len() as u32);
+		}
+		#[cfg(not(feature = "wasm-nice-panic-message"))]
+		{
+			if let Some(loc) = info.location() {
+				extern_functions_host_impl::ext_print_utf8(loc.file().as_ptr() as *const u8, loc.file().len() as u32);
+				extern_functions_host_impl::ext_print_num(loc.line() as u64);
+				extern_functions_host_impl::ext_print_num(loc.column() as u64);
+			}
 		}
 		intrinsics::abort()
 	}
@@ -43,41 +51,223 @@ pub extern fn oom(_: ::core::alloc::Layout) -> ! {
 	static OOM_MSG: &str = "Runtime memory exhausted. Aborting";
 
 	unsafe {
-		ext_print_utf8(OOM_MSG.as_ptr(), OOM_MSG.len() as u32);
+		extern_functions_host_impl::ext_print_utf8(OOM_MSG.as_ptr(), OOM_MSG.len() as u32);
 		intrinsics::abort();
 	}
 }
 
+/// The state of an exchangeable function.
+#[derive(Clone, Copy)]
+enum ExchangeableFunctionState {
+	Original,
+	Replaced,
+}
+
+/// A function which implementation can be exchanged.
+///
+/// Internally this works by swapping function pointers.
+pub struct ExchangeableFunction<T>(Cell<(T, ExchangeableFunctionState)>);
+
+impl<T> ExchangeableFunction<T> {
+	/// Create a new instance of `ExchangeableFunction`.
+	pub const fn new(impl_: T) -> Self {
+		Self(Cell::new((impl_, ExchangeableFunctionState::Original)))
+	}
+}
+
+impl<T: Copy> ExchangeableFunction<T> {
+	/// Replace the implementation with `new_impl`.
+	///
+	/// # Panics
+	///
+	/// Panics when trying to replace an already replaced implementation.
+	///
+	/// # Returns
+	///
+	/// Returns the original implementation wrapped in [`RestoreImplementation`].
+	pub fn replace_implementation(&'static self, new_impl: T)  -> RestoreImplementation<T> {
+		if let ExchangeableFunctionState::Replaced = self.0.get().1 {
+			panic!("Trying to replace an already replaced implementation!")
+		}
+
+		let old = self.0.replace((new_impl, ExchangeableFunctionState::Replaced));
+
+		RestoreImplementation(self, Some(old.0))
+	}
+
+	/// Restore the original implementation.
+	fn restore_orig_implementation(&self, orig: T) {
+		self.0.set((orig, ExchangeableFunctionState::Original));
+	}
+
+	/// Returns the internal function pointer.
+	pub fn get(&self) -> T {
+		self.0.get().0
+	}
+}
+
+// WASM does not support threads, so this is safe; qed.
+unsafe impl<T> Sync for ExchangeableFunction<T> {}
+
+/// Restores a function implementation on drop.
+///
+/// Stores a static reference to the function object and the original implementation.
+pub struct RestoreImplementation<T: 'static + Copy>(&'static ExchangeableFunction<T>, Option<T>);
+
+impl<T: Copy> Drop for RestoreImplementation<T> {
+	fn drop(&mut self) {
+		self.0.restore_orig_implementation(self.1.take().expect("Value is only taken on drop; qed"));
+	}
+}
+
+/// Declare extern functions
+macro_rules! extern_functions {
+	(
+		$(
+			$( #[$attr:meta] )*
+			fn $name:ident ( $( $arg:ident : $arg_ty:ty ),* ) $( -> $ret:ty )?;
+		)*
+	) => {
+		$(
+			$( #[$attr] )*
+			#[allow(non_upper_case_globals)]
+			pub static $name: ExchangeableFunction<unsafe fn ( $( $arg_ty ),* ) $( -> $ret )?> =
+				ExchangeableFunction::new(extern_functions_host_impl::$name);
+		)*
+
+		/// The exchangeable extern functions host implementations.
+		mod extern_functions_host_impl {
+			$(
+				pub unsafe fn $name ( $( $arg : $arg_ty ),* ) $( -> $ret )? {
+					implementation::$name ( $( $arg ),* )
+				}
+			)*
+
+			mod implementation {
+				extern "C" {
+					$(
+						pub fn $name ( $( $arg : $arg_ty ),* ) $( -> $ret )?;
+					)*
+				}
+			}
+		}
+	};
+}
+
 /// Host functions, provided by the executor.
 /// A WebAssembly runtime module would "import" these to access the execution environment
 /// (most importantly, storage) or perform heavy hash calculations.
 /// See also "ext_" functions in sr-sandbox and sr-std
-extern "C" {
-	/// Printing, useful for debugging
+extern_functions! {
+	/// Host functions for printing, useful for debugging.
 	fn ext_print_utf8(utf8_data: *const u8, utf8_len: u32);
 	fn ext_print_hex(data: *const u8, len: u32);
 	fn ext_print_num(value: u64);
 
-	/// Host storage access and verification
+	/// Set value for key in storage.
 	fn ext_set_storage(key_data: *const u8, key_len: u32, value_data: *const u8, value_len: u32);
-	fn ext_set_child_storage(storage_key_data: *const u8, storage_key_len: u32, key_data: *const u8, key_len: u32, value_data: *const u8, value_len: u32);
+	/// Remove key and value from storage.
 	fn ext_clear_storage(key_data: *const u8, key_len: u32);
-	fn ext_clear_child_storage(storage_key_data: *const u8, storage_key_len: u32, key_data: *const u8, key_len: u32);
+	/// Checks if the given key exists in the storage.
+	///
+	/// # Returns
+	///
+	/// - `1` if the value exists.
+	/// - `0` if the value does not exists.
 	fn ext_exists_storage(key_data: *const u8, key_len: u32) -> u32;
-	fn ext_exists_child_storage(storage_key_data: *const u8, storage_key_len: u32, key_data: *const u8, key_len: u32) -> u32;
+	/// Remove storage entries which key starts with given prefix.
 	fn ext_clear_prefix(prefix_data: *const u8, prefix_len: u32);
-	fn ext_kill_child_storage(storage_key_data: *const u8, storage_key_len: u32);
-	/// Host-side result allocation
+	/// Gets the value of the given key from storage.
+	///
+	/// The host allocates the memory for storing the value.
+	///
+	/// # Returns
+	///
+	/// - `0` if no value exists to the given key. `written_out` is set to `u32::max_value()`.
+	///
+	/// - Otherwise, pointer to the value in memory. `written_out` contains the length of the value.
 	fn ext_get_allocated_storage(key_data: *const u8, key_len: u32, written_out: *mut u32) -> *mut u8;
-	/// Host-side result allocation
-	fn ext_get_allocated_child_storage(storage_key_data: *const u8, storage_key_len: u32, key_data: *const u8, key_len: u32, written_out: *mut u32) -> *mut u8;
+	/// Gets the value of the given key from storage.
+	///
+	/// The value is written into `value` starting at `value_offset`.
+	///
+	/// If the value length is greater than `value_len - value_offset`, the value is written partially.
+	///
+	/// # Returns
+	///
+	/// - `u32::max_value()` if the value does not exists.
+	///
+	/// - Otherwise, the number of bytes written for value.
 	fn ext_get_storage_into(key_data: *const u8, key_len: u32, value_data: *mut u8, value_len: u32, value_offset: u32) -> u32;
-	fn ext_get_child_storage_into(storage_key_data: *const u8, storage_key_len: u32, key_data: *const u8, key_len: u32, value_data: *mut u8, value_len: u32, value_offset: u32) -> u32;
+	/// Gets the trie root of the storage.
 	fn ext_storage_root(result: *mut u8);
-	/// Host-side result allocation
-	fn ext_child_storage_root(storage_key_data: *const u8, storage_key_len: u32, written_out: *mut u32) -> *mut u8;
+	/// Get the change trie root of the current storage overlay at a block with given parent.
+	///
+	/// # Returns
+	///
+	/// - `1` if the change trie root was found.
+	/// - `0` if the change trie root was not found.
 	fn ext_storage_changes_root(parent_hash_data: *const u8, parent_hash_len: u32, parent_num: u64, result: *mut u8) -> u32;
 
+	/// A child storage function.
+	///
+	/// See [`ext_set_storage`] for details.
+	///
+	/// A child storage is used e.g. by a contract.
+	fn ext_set_child_storage(storage_key_data: *const u8, storage_key_len: u32, key_data: *const u8, key_len: u32, value_data: *const u8, value_len: u32);
+	/// A child storage function.
+	///
+	/// See [`ext_clear_storage`] for details.
+	///
+	/// A child storage is used e.g. by a contract.
+	fn ext_clear_child_storage(storage_key_data: *const u8, storage_key_len: u32, key_data: *const u8, key_len: u32);
+	/// A child storage function.
+	///
+	/// See [`ext_exists_storage`] for details.
+	///
+	/// A child storage is used e.g. by a contract.
+	fn ext_exists_child_storage(storage_key_data: *const u8, storage_key_len: u32, key_data: *const u8, key_len: u32) -> u32;
+	/// A child storage function.
+	///
+	/// See [`ext_kill_storage`] for details.
+	///
+	/// A child storage is used e.g. by a contract.
+	fn ext_kill_child_storage(storage_key_data: *const u8, storage_key_len: u32);
+	/// A child storage function.
+	///
+	/// See [`ext_get_allocated_storage`] for details.
+	///
+	/// A child storage is used e.g. by a contract.
+	fn ext_get_allocated_child_storage(
+		storage_key_data: *const u8,
+		storage_key_len: u32,
+		key_data: *const u8,
+		key_len: u32,
+		written_out: *mut u32
+	) -> *mut u8;
+	/// A child storage function.
+	///
+	/// See [`ext_get_storage_into`] for details.
+	///
+	/// A child storage is used e.g. by a contract.
+	fn ext_get_child_storage_into(
+		storage_key_data: *const u8,
+		storage_key_len: u32,
+		key_data: *const u8,
+		key_len: u32,
+		value_data: *mut u8,
+		value_len: u32,
+		value_offset: u32
+	) -> u32;
+	/// Commits all changes and calculates the child-storage root.
+	///
+	/// A child storage is used e.g. by a contract.
+	///
+	/// # Returns
+	///
+	/// - The pointer to the result vector and `written_out` contains its length.
+	fn ext_child_storage_root(storage_key_data: *const u8, storage_key_len: u32, written_out: *mut u32) -> *mut u8;
+
 	/// The current relay chain identifier.
 	fn ext_chain_id() -> u64;
 
@@ -107,7 +297,7 @@ impl ExternTrieCrypto for Blake2Hasher {
 		let values = values.iter().fold(Vec::new(), |mut acc, sl| { acc.extend_from_slice(sl); acc });
 		let mut result: [u8; 32] = Default::default();
 		unsafe {
-			ext_blake2_256_enumerated_trie_root(
+			ext_blake2_256_enumerated_trie_root.get()(
 				values.as_ptr(),
 				lengths.as_ptr(),
 				lengths.len() as u32,
@@ -122,7 +312,7 @@ impl ExternTrieCrypto for Blake2Hasher {
 pub fn storage(key: &[u8]) -> Option<Vec<u8>> {
 	let mut length: u32 = 0;
 	unsafe {
-		let ptr = ext_get_allocated_storage(key.as_ptr(), key.len() as u32, &mut length);
+		let ptr = ext_get_allocated_storage.get()(key.as_ptr(), key.len() as u32, &mut length);
 		if length == u32::max_value() {
 			None
 		} else {
@@ -138,7 +328,13 @@ pub fn storage(key: &[u8]) -> Option<Vec<u8>> {
 pub fn child_storage(storage_key: &[u8], key: &[u8]) -> Option<Vec<u8>> {
 	let mut length: u32 = 0;
 	unsafe {
-		let ptr = ext_get_allocated_child_storage(storage_key.as_ptr(), storage_key.len() as u32, key.as_ptr(), key.len() as u32, &mut length);
+		let ptr = ext_get_allocated_child_storage.get()(
+			storage_key.as_ptr(),
+			storage_key.len() as u32,
+			key.as_ptr(),
+			key.len() as u32,
+			&mut length
+		);
 		if length == u32::max_value() {
 			None
 		} else {
@@ -153,7 +349,7 @@ pub fn child_storage(storage_key: &[u8], key: &[u8]) -> Option<Vec<u8>> {
 /// Set the storage of some particular key to Some value.
 pub fn set_storage(key: &[u8], value: &[u8]) {
 	unsafe {
-		ext_set_storage(
+		ext_set_storage.get()(
 			key.as_ptr(), key.len() as u32,
 			value.as_ptr(), value.len() as u32
 		);
@@ -163,7 +359,7 @@ pub fn set_storage(key: &[u8], value: &[u8]) {
 /// Set the child storage of some particular key to Some value.
 pub fn set_child_storage(storage_key: &[u8], key: &[u8], value: &[u8]) {
 	unsafe {
-		ext_set_child_storage(
+		ext_set_child_storage.get()(
 			storage_key.as_ptr(), key.len() as u32,
 			key.as_ptr(), key.len() as u32,
 			value.as_ptr(), value.len() as u32
@@ -174,7 +370,7 @@ pub fn set_child_storage(storage_key: &[u8], key: &[u8], value: &[u8]) {
 /// Clear the storage of some particular key.
 pub fn clear_storage(key: &[u8]) {
 	unsafe {
-		ext_clear_storage(
+		ext_clear_storage.get()(
 			key.as_ptr(), key.len() as u32
 		);
 	}
@@ -183,7 +379,7 @@ pub fn clear_storage(key: &[u8]) {
 /// Clear the storage of some particular key.
 pub fn clear_child_storage(storage_key: &[u8], key: &[u8]) {
 	unsafe {
-		ext_clear_child_storage(
+		ext_clear_child_storage.get()(
 			storage_key.as_ptr(), storage_key.len() as u32,
 			key.as_ptr(), key.len() as u32
 		);
@@ -193,7 +389,7 @@ pub fn clear_child_storage(storage_key: &[u8], key: &[u8]) {
 /// Determine whether a particular key exists in storage.
 pub fn exists_storage(key: &[u8]) -> bool {
 	unsafe {
-		ext_exists_storage(
+		ext_exists_storage.get()(
 			key.as_ptr(), key.len() as u32
 		) != 0
 	}
@@ -202,7 +398,7 @@ pub fn exists_storage(key: &[u8]) -> bool {
 /// Determine whether a particular key exists in storage.
 pub fn exists_child_storage(storage_key: &[u8], key: &[u8]) -> bool {
 	unsafe {
-		ext_exists_child_storage(
+		ext_exists_child_storage.get()(
 			storage_key.as_ptr(), storage_key.len() as u32,
 			key.as_ptr(), key.len() as u32
 		) != 0
@@ -212,7 +408,7 @@ pub fn exists_child_storage(storage_key: &[u8], key: &[u8]) -> bool {
 /// Clear the storage entries key of which starts with the given prefix.
 pub fn clear_prefix(prefix: &[u8]) {
 	unsafe {
-		ext_clear_prefix(
+		ext_clear_prefix.get()(
 			prefix.as_ptr(),
 			prefix.len() as u32
 		);
@@ -222,7 +418,7 @@ pub fn clear_prefix(prefix: &[u8]) {
 /// Clear an entire child storage.
 pub fn kill_child_storage(storage_key: &[u8]) {
 	unsafe {
-		ext_kill_child_storage(
+		ext_kill_child_storage.get()(
 			storage_key.as_ptr(),
 			storage_key.len() as u32
 		);
@@ -233,10 +429,12 @@ pub fn kill_child_storage(storage_key: &[u8]) {
 /// the number of bytes that the key in storage was beyond the offset.
 pub fn read_storage(key: &[u8], value_out: &mut [u8], value_offset: usize) -> Option<usize> {
 	unsafe {
-		match ext_get_storage_into(
-			key.as_ptr(), key.len() as u32,
-			value_out.as_mut_ptr(), value_out.len() as u32,
-			value_offset as u32
+		match ext_get_storage_into.get()(
+			key.as_ptr(),
+			key.len() as u32,
+			value_out.as_mut_ptr(),
+			value_out.len() as u32,
+			value_offset as u32,
 		) {
 			none if none == u32::max_value() => None,
 			length => Some(length as usize),
@@ -248,7 +446,7 @@ pub fn read_storage(key: &[u8], value_out: &mut [u8], value_offset: usize) -> Op
 /// the number of bytes that the key in storage was beyond the offset.
 pub fn read_child_storage(storage_key: &[u8], key: &[u8], value_out: &mut [u8], value_offset: usize) -> Option<usize> {
 	unsafe {
-		match ext_get_child_storage_into(
+		match ext_get_child_storage_into.get()(
 			storage_key.as_ptr(), storage_key.len() as u32,
 			key.as_ptr(), key.len() as u32,
 			value_out.as_mut_ptr(), value_out.len() as u32,
@@ -264,7 +462,7 @@ pub fn read_child_storage(storage_key: &[u8], key: &[u8], value_out: &mut [u8],
 pub fn storage_root() -> [u8; 32] {
 	let mut result: [u8; 32] = Default::default();
 	unsafe {
-		ext_storage_root(result.as_mut_ptr());
+		ext_storage_root.get()(result.as_mut_ptr());
 	}
 	result
 }
@@ -273,7 +471,7 @@ pub fn storage_root() -> [u8; 32] {
 pub fn child_storage_root(storage_key: &[u8]) -> Option<Vec<u8>> {
 	let mut length: u32 = 0;
 	unsafe {
-		let ptr = ext_child_storage_root(storage_key.as_ptr(), storage_key.len() as u32, &mut length);
+		let ptr = ext_child_storage_root.get()(storage_key.as_ptr(), storage_key.len() as u32, &mut length);
 		if length == u32::max_value() {
 			None
 		} else {
@@ -289,7 +487,7 @@ pub fn child_storage_root(storage_key: &[u8]) -> Option<Vec<u8>> {
 pub fn storage_changes_root(parent_hash: [u8; 32], parent_num: u64) -> Option<[u8; 32]> {
 	let mut result: [u8; 32] = Default::default();
 	let is_set = unsafe {
-		ext_storage_changes_root(parent_hash.as_ptr(), parent_hash.len() as u32, parent_num, result.as_mut_ptr())
+		ext_storage_changes_root.get()(parent_hash.as_ptr(), parent_hash.len() as u32, parent_num, result.as_mut_ptr())
 	};
 
 	if is_set != 0 {
@@ -326,7 +524,7 @@ pub fn ordered_trie_root<
 /// The current relay chain identifier.
 pub fn chain_id() -> u64 {
 	unsafe {
-		ext_chain_id()
+		ext_chain_id.get()()
 	}
 }
 
@@ -334,7 +532,7 @@ pub fn chain_id() -> u64 {
 pub fn blake2_256(data: &[u8]) -> [u8; 32] {
 	let mut result: [u8; 32] = Default::default();
 	unsafe {
-		ext_blake2_256(data.as_ptr(), data.len() as u32, result.as_mut_ptr());
+		ext_blake2_256.get()(data.as_ptr(), data.len() as u32, result.as_mut_ptr());
 	}
 	result
 }
@@ -343,7 +541,7 @@ pub fn blake2_256(data: &[u8]) -> [u8; 32] {
 pub fn keccak_256(data: &[u8]) -> [u8; 32] {
 	let mut result: [u8; 32] = Default::default();
 	unsafe {
-		ext_keccak_256(data.as_ptr(), data.len() as u32, result.as_mut_ptr());
+		ext_keccak_256.get()(data.as_ptr(), data.len() as u32, result.as_mut_ptr());
 	}
 	result
 }
@@ -352,7 +550,7 @@ pub fn keccak_256(data: &[u8]) -> [u8; 32] {
 pub fn twox_256(data: &[u8]) -> [u8; 32] {
 	let mut result: [u8; 32] = Default::default();
 	unsafe {
-		ext_twox_256(data.as_ptr(), data.len() as u32, result.as_mut_ptr());
+		ext_twox_256.get()(data.as_ptr(), data.len() as u32, result.as_mut_ptr());
 	}
 	result
 }
@@ -361,7 +559,7 @@ pub fn twox_256(data: &[u8]) -> [u8; 32] {
 pub fn twox_128(data: &[u8]) -> [u8; 16] {
 	let mut result: [u8; 16] = Default::default();
 	unsafe {
-		ext_twox_128(data.as_ptr(), data.len() as u32, result.as_mut_ptr());
+		ext_twox_128.get()(data.as_ptr(), data.len() as u32, result.as_mut_ptr());
 	}
 	result
 }
@@ -369,14 +567,14 @@ pub fn twox_128(data: &[u8]) -> [u8; 16] {
 /// Verify a ed25519 signature.
 pub fn ed25519_verify<P: AsRef<[u8]>>(sig: &[u8; 64], msg: &[u8], pubkey: P) -> bool {
 	unsafe {
-		ext_ed25519_verify(msg.as_ptr(), msg.len() as u32, sig.as_ptr(), pubkey.as_ref().as_ptr()) == 0
+		ext_ed25519_verify.get()(msg.as_ptr(), msg.len() as u32, sig.as_ptr(), pubkey.as_ref().as_ptr()) == 0
 	}
 }
 
 /// Verify a sr25519 signature.
 pub fn sr25519_verify<P: AsRef<[u8]>>(sig: &[u8; 64], msg: &[u8], pubkey: P) -> bool {
 	unsafe {
-		ext_sr25519_verify(msg.as_ptr(), msg.len() as u32, sig.as_ptr(), pubkey.as_ref().as_ptr()) == 0
+		ext_sr25519_verify.get()(msg.as_ptr(), msg.len() as u32, sig.as_ptr(), pubkey.as_ref().as_ptr()) == 0
 	}
 }
 
@@ -386,7 +584,7 @@ pub fn sr25519_verify<P: AsRef<[u8]>>(sig: &[u8; 64], msg: &[u8], pubkey: P) ->
 pub fn secp256k1_ecdsa_recover(sig: &[u8; 65], msg: &[u8; 32]) -> Result<[u8; 64], EcdsaVerifyError> {
 	let mut pubkey = [0u8; 64];
 	match unsafe {
-		ext_secp256k1_ecdsa_recover(msg.as_ptr(), sig.as_ptr(), pubkey.as_mut_ptr())
+		ext_secp256k1_ecdsa_recover.get()(msg.as_ptr(), sig.as_ptr(), pubkey.as_mut_ptr())
 	} {
 		0 => Ok(pubkey),
 		1 => Err(EcdsaVerifyError::BadRS),
@@ -404,7 +602,7 @@ pub trait Printable {
 impl<'a> Printable for &'a [u8] {
 	fn print(self) {
 		unsafe {
-			ext_print_hex(self.as_ptr(), self.len() as u32);
+			ext_print_hex.get()(self.as_ptr(), self.len() as u32);
 		}
 	}
 }
@@ -412,14 +610,14 @@ impl<'a> Printable for &'a [u8] {
 impl<'a> Printable for &'a str {
 	fn print(self) {
 		unsafe {
-			ext_print_utf8(self.as_ptr() as *const u8, self.len() as u32);
+			ext_print_utf8.get()(self.as_ptr() as *const u8, self.len() as u32);
 		}
 	}
 }
 
 impl Printable for u64 {
 	fn print(self) {
-		unsafe { ext_print_num(self); }
+		unsafe { ext_print_num.get()(self); }
 	}
 }
 
diff --git a/core/state-machine/src/lib.rs b/core/state-machine/src/lib.rs
index ede2bf40b0f67..135c1dfc6be66 100644
--- a/core/state-machine/src/lib.rs
+++ b/core/state-machine/src/lib.rs
@@ -151,7 +151,7 @@ pub trait Externalities<H: Hasher> {
 	/// Returns None if key provided is not a storage key. This can due to not being started with CHILD_STORAGE_KEY_PREFIX, or the trie implementation regards the key as invalid.
 	fn child_storage_root(&mut self, storage_key: &[u8]) -> Option<Vec<u8>>;
 
-	/// Get the change trie root of the current storage overlay at a block wth given parent.
+	/// Get the change trie root of the current storage overlay at a block with given parent.
 	fn storage_changes_root(&mut self, parent: H::Out, parent_num: u64) -> Option<H::Out> where H::Out: Ord;
 }
 
diff --git a/core/test-runtime/Cargo.toml b/core/test-runtime/Cargo.toml
index e4dda6a397f88..bddabbe928c96 100644
--- a/core/test-runtime/Cargo.toml
+++ b/core/test-runtime/Cargo.toml
@@ -20,6 +20,7 @@ runtime_io = { package = "sr-io", path = "../sr-io", default-features = false }
 runtime_primitives = { package = "sr-primitives", path = "../sr-primitives", default-features = false }
 runtime_version = { package = "sr-version", path = "../sr-version", default-features = false }
 runtime_support = { package = "srml-support", path = "../../srml/support", default-features = false }
+executive = { package = "srml-executive", path = "../../srml/executive", default-features = false }
 cfg-if = "0.1.6"
 
 [dev-dependencies]
@@ -44,4 +45,5 @@ std = [
 	"runtime_primitives/std",
 	"runtime_version/std",
 	"consensus_aura/std",
+	"executive/std",
 ]
diff --git a/core/test-runtime/src/lib.rs b/core/test-runtime/src/lib.rs
index b345c06e6cb4e..9c6f26e4a0455 100644
--- a/core/test-runtime/src/lib.rs
+++ b/core/test-runtime/src/lib.rs
@@ -18,7 +18,8 @@
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
-#[cfg(feature = "std")] pub mod genesismap;
+#[cfg(feature = "std")]
+pub mod genesismap;
 pub mod system;
 
 use rstd::{prelude::*, marker::PhantomData};
@@ -77,6 +78,16 @@ pub struct Transfer {
 	pub nonce: u64,
 }
 
+impl Transfer {
+	/// Convert into a signed extrinsic.
+	#[cfg(feature = "std")]
+	pub fn into_signed_tx(self) -> Extrinsic {
+		let signature = keyring::AccountKeyring::from_public(&self.from)
+			.expect("Creates keyring from public key.").sign(&self.encode()).into();
+		Extrinsic::Transfer(self, signature)
+	}
+}
+
 /// Extrinsic for test-runtime.
 #[derive(Clone, PartialEq, Eq, Encode, Decode)]
 #[cfg_attr(feature = "std", derive(Debug))]
@@ -219,6 +230,8 @@ cfg_if! {
 				fn function_signature_changed() -> u64;
 				fn fail_on_native() -> u64;
 				fn fail_on_wasm() -> u64;
+				fn benchmark_indirect_call() -> u64;
+				fn benchmark_direct_call() -> u64;
 			}
 		}
 	} else {
@@ -239,6 +252,8 @@ cfg_if! {
 				fn function_signature_changed() -> Vec<u64>;
 				fn fail_on_native() -> u64;
 				fn fail_on_wasm() -> u64;
+				fn benchmark_indirect_call() -> u64;
+				fn benchmark_direct_call() -> u64;
 			}
 		}
 	}
@@ -254,6 +269,16 @@ impl GetRuntimeBlockType for Runtime {
 	type RuntimeBlock = Block;
 }
 
+/// Adds one to the given input and returns the final result.
+#[inline(never)]
+fn benchmark_add_one(i: u64) -> u64 {
+	i + 1
+}
+
+/// The `benchmark_add_one` function as function pointer.
+#[cfg(not(feature = "std"))]
+static BENCHMARK_ADD_ONE: runtime_io::ExchangeableFunction<fn(u64) -> u64> = runtime_io::ExchangeableFunction::new(benchmark_add_one);
+
 cfg_if! {
 	if #[cfg(feature = "std")] {
 		impl_runtime_apis! {
@@ -340,6 +365,13 @@ cfg_if! {
 				fn fail_on_wasm() -> u64 {
 					1
 				}
+				fn benchmark_indirect_call() -> u64 {
+					let function = benchmark_add_one;
+					(0..1000).fold(0, |p, i| p + function(i))
+				}
+				fn benchmark_direct_call() -> u64 {
+					(0..1000).fold(0, |p, i| p + benchmark_add_one(i))
+				}
 			}
 
 			impl consensus_aura::AuraApi<Block> for Runtime {
@@ -435,6 +467,14 @@ cfg_if! {
 				fn fail_on_wasm() -> u64 {
 					panic!("Failing because we are on wasm")
 				}
+
+				fn benchmark_indirect_call() -> u64 {
+					(0..10000).fold(0, |p, i| p + BENCHMARK_ADD_ONE.get()(i))
+				}
+
+				fn benchmark_direct_call() -> u64 {
+					(0..10000).fold(0, |p, i| p + benchmark_add_one(i))
+				}
 			}
 
 			impl consensus_aura::AuraApi<Block> for Runtime {
@@ -442,4 +482,4 @@ cfg_if! {
 			}
 		}
 	}
-}
+}
\ No newline at end of file
diff --git a/core/test-runtime/src/system.rs b/core/test-runtime/src/system.rs
index f1e04473ece18..a66eb58c1f482 100644
--- a/core/test-runtime/src/system.rs
+++ b/core/test-runtime/src/system.rs
@@ -21,7 +21,7 @@ use rstd::prelude::*;
 use runtime_io::{storage_root, enumerated_trie_root, storage_changes_root, twox_128};
 use runtime_support::storage::{self, StorageValue, StorageMap};
 use runtime_support::storage_items;
-use runtime_primitives::traits::{Hash as HashT, BlakeTwo256, Digest as DigestT};
+use runtime_primitives::traits::{Hash as HashT, BlakeTwo256, Digest as DigestT, NumberFor, Block as BlockT};
 use runtime_primitives::generic;
 use runtime_primitives::{ApplyError, ApplyOutcome, ApplyResult, transaction_validity::TransactionValidity};
 use parity_codec::{KeyedVec, Encode};
@@ -70,6 +70,15 @@ pub fn initialise_block(header: &Header) {
 	storage::unhashed::put(well_known_keys::EXTRINSIC_INDEX, &0u32);
 }
 
+fn execute_extrinsics_without_checks(extrinsics: Vec<<Block as BlockT>::Extrinsic>) {
+	// execute transactions
+	extrinsics.into_iter().enumerate().for_each(|(i, e)| {
+		storage::unhashed::put(well_known_keys::EXTRINSIC_INDEX, &(i as u32));
+		execute_transaction_backend(&e).unwrap_or_else(|_| panic!("Invalid transaction"));
+		storage::unhashed::kill(well_known_keys::EXTRINSIC_INDEX);
+	});
+}
+
 /// Actually execute all transitioning for `block`.
 pub fn polish_block(block: &mut Block) {
 	let header = &mut block.header;
@@ -111,12 +120,7 @@ pub fn execute_block(block: Block) {
 	info_expect_equal_hash(&txs_root, &header.extrinsics_root);
 	assert!(txs_root == header.extrinsics_root, "Transaction trie root must be valid.");
 
-	// execute transactions
-	block.extrinsics.iter().enumerate().for_each(|(i, e)| {
-	storage::unhashed::put(well_known_keys::EXTRINSIC_INDEX, &(i as u32));
-	execute_transaction_backend(e).unwrap_or_else(|_| panic!("Invalid transaction"));
-	storage::unhashed::kill(well_known_keys::EXTRINSIC_INDEX);
-	});
+	execute_extrinsics_without_checks(block.extrinsics);
 
 	// check storage root.
 	let storage_root = storage_root().into();
@@ -134,6 +138,19 @@ pub fn execute_block(block: Block) {
 	assert!(digest == header.digest, "Header digest items must match that calculated.");
 }
 
+/// The block executor.
+pub struct BlockExecutor;
+
+impl executive::ExecuteBlock<Block> for BlockExecutor {
+	fn execute_block(block: Block) {
+		execute_block(block);
+	}
+
+	fn execute_extrinsics_without_checks(_: NumberFor<Block>, extrinsics: Vec<<Block as BlockT>::Extrinsic>) {
+		execute_extrinsics_without_checks(extrinsics);
+	}
+}
+
 /// Execute a transaction outside of the block execution function.
 /// This doesn't attempt to validate anything regarding the block.
 pub fn validate_transaction(utx: Extrinsic) -> TransactionValidity {
@@ -307,11 +324,6 @@ mod tests {
 		])
 	}
 
-	fn construct_signed_tx(tx: Transfer) -> Extrinsic {
-		let signature = AccountKeyring::from_public(&tx.from).unwrap().sign(&tx.encode()).into();
-		Extrinsic::Transfer(tx, signature)
-	}
-
 	fn block_import_works<F>(block_executor: F) where F: Fn(Block, &mut TestExternalities<Blake2Hasher>) {
 		let h = Header {
 			parent_hash: [69u8; 32].into(),
@@ -356,12 +368,12 @@ mod tests {
 				digest: Default::default(),
 			},
 			extrinsics: vec![
-				construct_signed_tx(Transfer {
+				Transfer {
 					from: AccountKeyring::Alice.into(),
 					to: AccountKeyring::Bob.into(),
 					amount: 69,
 					nonce: 0,
-				})
+				}.into_signed_tx()
 			],
 		};
 
@@ -377,18 +389,18 @@ mod tests {
 				digest: Default::default(),
 			},
 			extrinsics: vec![
-				construct_signed_tx(Transfer {
+				Transfer {
 					from: AccountKeyring::Bob.into(),
 					to: AccountKeyring::Alice.into(),
 					amount: 27,
 					nonce: 0,
-				}),
-				construct_signed_tx(Transfer {
+				}.into_signed_tx(),
+				Transfer {
 					from: AccountKeyring::Alice.into(),
 					to: AccountKeyring::Charlie.into(),
 					amount: 69,
 					nonce: 1,
-				}),
+				}.into_signed_tx(),
 			],
 		};
 
diff --git a/core/test-runtime/wasm/Cargo.lock b/core/test-runtime/wasm/Cargo.lock
index a5b87b4436956..0746e5aa81f3e 100644
--- a/core/test-runtime/wasm/Cargo.lock
+++ b/core/test-runtime/wasm/Cargo.lock
@@ -61,7 +61,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 [[package]]
 name = "bitmask"
 version = "0.5.0"
-source = "git+https://github.com/paritytech/bitmask#c2d8d196e30b018d1385be8357fdca61b978facf"
+source = "git+https://github.com/paritytech/bitmask#a84e147be602631617badd18b6b9af83391db4a9"
 
 [[package]]
 name = "blake2-rfc"
@@ -378,7 +378,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 0.4.27 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.11 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.27 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.29 (registry+https://github.com/rust-lang/crates.io-index)",
  "synstructure 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -854,7 +854,7 @@ dependencies = [
  "proc-macro-crate 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "proc-macro2 0.4.27 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.11 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.27 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.29 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -903,7 +903,7 @@ dependencies = [
  "proc-macro-hack 0.5.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "proc-macro2 0.4.27 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.11 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.27 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.29 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -960,7 +960,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 0.4.27 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.11 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.27 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.29 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1194,6 +1194,14 @@ name = "ryu"
 version = "0.2.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "safe-mix"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "schnorrkel"
 version = "0.0.0"
@@ -1241,7 +1249,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 0.4.27 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.11 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.27 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.29 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1353,7 +1361,7 @@ dependencies = [
  "proc-macro-crate 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "proc-macro2 0.4.27 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.11 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.27 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.29 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1406,6 +1414,19 @@ dependencies = [
  "sr-std 0.1.0",
 ]
 
+[[package]]
+name = "srml-executive"
+version = "0.1.0"
+dependencies = [
+ "parity-codec 3.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.89 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sr-io 0.1.0",
+ "sr-primitives 0.1.0",
+ "sr-std 0.1.0",
+ "srml-support 0.1.0",
+ "srml-system 0.1.0",
+]
+
 [[package]]
 name = "srml-metadata"
 version = "0.1.0"
@@ -1444,7 +1465,7 @@ dependencies = [
  "quote 0.6.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-api-macros 0.1.0",
  "srml-support-procedural-tools 0.1.0",
- "syn 0.15.27 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.29 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1455,7 +1476,7 @@ dependencies = [
  "proc-macro2 0.4.27 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "srml-support-procedural-tools-derive 0.1.0",
- "syn 0.15.27 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.29 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1464,7 +1485,23 @@ version = "0.1.0"
 dependencies = [
  "proc-macro2 0.4.27 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.11 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.27 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.29 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "srml-system"
+version = "0.1.0"
+dependencies = [
+ "hex-literal 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 3.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "safe-mix 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.89 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_derive 1.0.89 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sr-io 0.1.0",
+ "sr-primitives 0.1.0",
+ "sr-std 0.1.0",
+ "srml-support 0.1.0",
+ "substrate-primitives 0.1.0",
 ]
 
 [[package]]
@@ -1677,6 +1714,7 @@ dependencies = [
  "sr-primitives 0.1.0",
  "sr-std 0.1.0",
  "sr-version 0.1.0",
+ "srml-executive 0.1.0",
  "srml-support 0.1.0",
  "substrate-client 0.1.0",
  "substrate-consensus-aura-primitives 0.1.0",
@@ -1715,7 +1753,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "syn"
-version = "0.15.27"
+version = "0.15.29"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 0.4.27 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1730,7 +1768,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 0.4.27 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.11 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.27 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.29 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -2262,6 +2300,7 @@ dependencies = [
 "checksum rustc-hex 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "403bb3a286107a04825a5f82e1270acc1e14028d3d554d7a1e08914549575ab8"
 "checksum rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "138e3e0acb6c9fb258b19b67cb8abd63c00679d2851805ea151465464fe9030a"
 "checksum ryu 0.2.7 (registry+https://github.com/rust-lang/crates.io-index)" = "eb9e9b8cde282a9fe6a42dd4681319bfb63f121b8a8ee9439c6f4107e58a46f7"
+"checksum safe-mix 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "7f7bf422d23a88c16d5090d455f182bc99c60af4df6a345c63428acf5129e347"
 "checksum schnorrkel 0.0.0 (git+https://github.com/w3f/schnorrkel)" = "<none>"
 "checksum scopeguard 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "94258f53601af11e6a49f722422f6e3425c52b06245a5cf9bc09908b174f5e27"
 "checksum semver 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "1d7eb9ef2c18661902cc47e535f9bc51b78acd254da71d375c2f6720d9a40403"
@@ -2285,7 +2324,7 @@ dependencies = [
 "checksum substrate-bip39 0.2.0 (git+https://github.com/paritytech/substrate-bip39)" = "<none>"
 "checksum subtle 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "2d67a5a62ba6e01cb2192ff309324cb4875d0c451d55fe2319433abe7a05a8ee"
 "checksum subtle 2.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "702662512f3ddeb74a64ce2fbbf3707ee1b6bb663d28bb054e0779bbc720d926"
-"checksum syn 0.15.27 (registry+https://github.com/rust-lang/crates.io-index)" = "525bd55255f03c816e5d7f615587bd13030c7103354fadb104993dcee6a788ec"
+"checksum syn 0.15.29 (registry+https://github.com/rust-lang/crates.io-index)" = "1825685f977249735d510a242a6727b46efe914bb67e38d30c071b1b72b1d5c2"
 "checksum synstructure 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)" = "73687139bf99285483c96ac0add482c3776528beac1d97d444f6e91f203a2015"
 "checksum take_mut 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "f764005d11ee5f36500a149ace24e00e3da98b0158b3e2d53a7495660d3f4d60"
 "checksum thread_local 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)" = "c6b53e329000edc2b34dbe8545fd20e55a333362d0a321909685a19bd28c3f1b"
diff --git a/core/test-runtime/wasm/target/wasm32-unknown-unknown/release/substrate_test_runtime.compact.wasm b/core/test-runtime/wasm/target/wasm32-unknown-unknown/release/substrate_test_runtime.compact.wasm
index e844c0124e12a..bff5d3c6fc95a 100644
Binary files a/core/test-runtime/wasm/target/wasm32-unknown-unknown/release/substrate_test_runtime.compact.wasm and b/core/test-runtime/wasm/target/wasm32-unknown-unknown/release/substrate_test_runtime.compact.wasm differ
diff --git a/node/runtime/src/lib.rs b/node/runtime/src/lib.rs
index 55293d3e46ed2..ae24c263f7825 100644
--- a/node/runtime/src/lib.rs
+++ b/node/runtime/src/lib.rs
@@ -62,7 +62,7 @@ pub const VERSION: RuntimeVersion = RuntimeVersion {
 	impl_name: create_runtime_str!("substrate-node"),
 	authoring_version: 10,
 	spec_version: 35,
-	impl_version: 36,
+	impl_version: 37,
 	apis: RUNTIME_API_VERSIONS,
 };
 
diff --git a/node/runtime/wasm/Cargo.lock b/node/runtime/wasm/Cargo.lock
index 543020eed7a47..7c87f49874daf 100644
--- a/node/runtime/wasm/Cargo.lock
+++ b/node/runtime/wasm/Cargo.lock
@@ -61,7 +61,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 [[package]]
 name = "bitmask"
 version = "0.5.0"
-source = "git+https://github.com/paritytech/bitmask#c2d8d196e30b018d1385be8357fdca61b978facf"
+source = "git+https://github.com/paritytech/bitmask#a84e147be602631617badd18b6b9af83391db4a9"
 
 [[package]]
 name = "blake2-rfc"
@@ -117,7 +117,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "bytes"
-version = "0.4.11"
+version = "0.4.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "byteorder 1.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -378,7 +378,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 0.4.27 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.11 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.27 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.29 (registry+https://github.com/rust-lang/crates.io-index)",
  "synstructure 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -913,7 +913,7 @@ dependencies = [
  "proc-macro-crate 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "proc-macro2 0.4.27 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.11 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.27 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.29 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -962,7 +962,7 @@ dependencies = [
  "proc-macro-hack 0.5.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "proc-macro2 0.4.27 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.11 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.27 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.29 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1019,7 +1019,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 0.4.27 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.11 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.27 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.29 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1318,7 +1318,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 0.4.27 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.11 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.27 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.29 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1430,7 +1430,7 @@ dependencies = [
  "proc-macro-crate 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "proc-macro2 0.4.27 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.11 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.27 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.29 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1764,7 +1764,7 @@ dependencies = [
  "quote 0.6.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-api-macros 0.1.0",
  "srml-support-procedural-tools 0.1.0",
- "syn 0.15.27 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.29 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1775,7 +1775,7 @@ dependencies = [
  "proc-macro2 0.4.27 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "srml-support-procedural-tools-derive 0.1.0",
- "syn 0.15.27 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.29 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1784,7 +1784,7 @@ version = "0.1.0"
 dependencies = [
  "proc-macro2 0.4.27 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.11 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.27 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.29 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -2075,7 +2075,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "syn"
-version = "0.15.27"
+version = "0.15.29"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 0.4.27 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2090,7 +2090,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 0.4.27 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.11 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.27 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.29 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -2144,7 +2144,7 @@ name = "tokio"
 version = "0.1.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "bytes 0.4.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "bytes 0.4.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.1.25 (registry+https://github.com/rust-lang/crates.io-index)",
  "mio 0.6.16 (registry+https://github.com/rust-lang/crates.io-index)",
  "num_cpus 1.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2167,7 +2167,7 @@ name = "tokio-codec"
 version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "bytes 0.4.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "bytes 0.4.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.1.25 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-io 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -2205,7 +2205,7 @@ name = "tokio-io"
 version = "0.1.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "bytes 0.4.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "bytes 0.4.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.1.25 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -2242,7 +2242,7 @@ name = "tokio-tcp"
 version = "0.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "bytes 0.4.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "bytes 0.4.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.1.25 (registry+https://github.com/rust-lang/crates.io-index)",
  "iovec 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "mio 0.6.16 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2282,7 +2282,7 @@ name = "tokio-udp"
 version = "0.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "bytes 0.4.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "bytes 0.4.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.1.25 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "mio 0.6.16 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2296,7 +2296,7 @@ name = "tokio-uds"
 version = "0.2.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "bytes 0.4.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "bytes 0.4.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.1.25 (registry+https://github.com/rust-lang/crates.io-index)",
  "iovec 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.50 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2455,7 +2455,7 @@ version = "0.7.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "byteorder 1.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "bytes 0.4.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "bytes 0.4.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "httparse 1.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "mio 0.6.16 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2493,7 +2493,7 @@ dependencies = [
 "checksum byte-tools 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "560c32574a12a89ecd91f5e742165893f86e3ab98d21f8ea548658eb9eef5f40"
 "checksum byte-tools 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "e3b5ca7a04898ad4bcd41c90c5285445ff5b791899bb1b0abdd2a2aa791211d7"
 "checksum byteorder 1.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "a019b10a2a7cdeb292db131fc8113e57ea2a908f6e7894b0c3c671893b65dbeb"
-"checksum bytes 0.4.11 (registry+https://github.com/rust-lang/crates.io-index)" = "40ade3d27603c2cb345eb0912aec461a6dec7e06a4ae48589904e808335c7afa"
+"checksum bytes 0.4.12 (registry+https://github.com/rust-lang/crates.io-index)" = "206fdffcfa2df7cbe15601ef46c813fce0965eb3286db6b56c583b814b51c81c"
 "checksum cc 1.0.30 (registry+https://github.com/rust-lang/crates.io-index)" = "d01c69d08ff207f231f07196e30f84c70f1c815b04f980f8b7b01ff01f05eb92"
 "checksum cfg-if 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)" = "11d43355396e872eefb45ce6342e4374ed7bc2b3a502d1b28e36d6e23c05d1f4"
 "checksum chrono 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)" = "45912881121cb26fad7c38c17ba7daa18764771836b34fab7d3fbd93ed633878"
@@ -2647,7 +2647,7 @@ dependencies = [
 "checksum substrate-bip39 0.2.0 (git+https://github.com/paritytech/substrate-bip39)" = "<none>"
 "checksum subtle 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "2d67a5a62ba6e01cb2192ff309324cb4875d0c451d55fe2319433abe7a05a8ee"
 "checksum subtle 2.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "702662512f3ddeb74a64ce2fbbf3707ee1b6bb663d28bb054e0779bbc720d926"
-"checksum syn 0.15.27 (registry+https://github.com/rust-lang/crates.io-index)" = "525bd55255f03c816e5d7f615587bd13030c7103354fadb104993dcee6a788ec"
+"checksum syn 0.15.29 (registry+https://github.com/rust-lang/crates.io-index)" = "1825685f977249735d510a242a6727b46efe914bb67e38d30c071b1b72b1d5c2"
 "checksum synstructure 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)" = "73687139bf99285483c96ac0add482c3776528beac1d97d444f6e91f203a2015"
 "checksum take_mut 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "f764005d11ee5f36500a149ace24e00e3da98b0158b3e2d53a7495660d3f4d60"
 "checksum thread_local 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)" = "c6b53e329000edc2b34dbe8545fd20e55a333362d0a321909685a19bd28c3f1b"
diff --git a/node/runtime/wasm/target/wasm32-unknown-unknown/release/node_runtime.compact.wasm b/node/runtime/wasm/target/wasm32-unknown-unknown/release/node_runtime.compact.wasm
index f18a1fd01dd5b..b8166f59e6e47 100644
Binary files a/node/runtime/wasm/target/wasm32-unknown-unknown/release/node_runtime.compact.wasm and b/node/runtime/wasm/target/wasm32-unknown-unknown/release/node_runtime.compact.wasm differ
diff --git a/srml/executive/src/lib.rs b/srml/executive/src/lib.rs
index d00c2693ffafb..b6cc498f79dac 100644
--- a/srml/executive/src/lib.rs
+++ b/srml/executive/src/lib.rs
@@ -18,12 +18,13 @@
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
-
 use rstd::prelude::*;
 use rstd::marker::PhantomData;
 use rstd::result;
-use primitives::traits::{self, Header, Zero, One, Checkable, Applyable, CheckEqual, OnFinalise,
-	OnInitialise, Hash, As, Digest};
+use primitives::traits::{
+	self, Header, Zero, One, Checkable, Applyable, CheckEqual, OnFinalise,
+	OnInitialise, Hash, As, Digest, NumberFor, Block as BlockT
+};
 use srml_support::{Dispatchable, traits::ChargeBytesFee};
 use parity_codec::{Codec, Encode};
 use system::extrinsics_root;
@@ -47,18 +48,43 @@ mod internal {
 	}
 }
 
-pub struct Executive<
-	System,
-	Block,
-	Context,
-	Payment,
-	AllModules,
->(PhantomData<(System, Block, Context, Payment, AllModules)>);
+/// Something that can be used to execute a block.
+pub trait ExecuteBlock<Block: BlockT> {
+	/// Actually execute all transitioning for `block`.
+	fn execute_block(block: Block);
+	/// Execute all extrinsics like when executing a `block`, but with dropping intial and final checks.
+	fn execute_extrinsics_without_checks(block_number: NumberFor<Block>, extrinsics: Vec<Block::Extrinsic>);
+}
+
+pub struct Executive<System, Block, Context, Payment, AllModules>(
+	PhantomData<(System, Block, Context, Payment, AllModules)>
+);
 
 impl<
+	System: system::Trait,
+	Block: traits::Block<Header=System::Header, Hash=System::Hash>,
 	Context: Default,
+	Payment: ChargeBytesFee<System::AccountId>,
+	AllModules: OnInitialise<System::BlockNumber> + OnFinalise<System::BlockNumber>,
+> ExecuteBlock<Block> for Executive<System, Block, Context, Payment, AllModules> where
+	Block::Extrinsic: Checkable<Context> + Codec,
+	<Block::Extrinsic as Checkable<Context>>::Checked: Applyable<Index=System::Index, AccountId=System::AccountId>,
+	<<Block::Extrinsic as Checkable<Context>>::Checked as Applyable>::Call: Dispatchable,
+	<<<Block::Extrinsic as Checkable<Context>>::Checked as Applyable>::Call as Dispatchable>::Origin: From<Option<System::AccountId>>
+{
+	fn execute_block(block: Block) {
+		Self::execute_block(block);
+	}
+
+	fn execute_extrinsics_without_checks(block_number: NumberFor<Block>, extrinsics: Vec<Block::Extrinsic>) {
+		Self::execute_extrinsics_without_checks(block_number, extrinsics);
+	}
+}
+
+impl<
 	System: system::Trait,
 	Block: traits::Block<Header=System::Header, Hash=System::Hash>,
+	Context: Default,
 	Payment: ChargeBytesFee<System::AccountId>,
 	AllModules: OnInitialise<System::BlockNumber> + OnFinalise<System::BlockNumber>,
 > Executive<System, Block, Context, Payment, AllModules> where
@@ -69,8 +95,12 @@ impl<
 {
 	/// Start the execution of a particular block.
 	pub fn initialise_block(header: &System::Header) {
-		<system::Module<System>>::initialise(header.number(), header.parent_hash(), header.extrinsics_root());
-		<AllModules as OnInitialise<System::BlockNumber>>::on_initialise(*header.number());
+		Self::initialise_block_impl(header.number(), header.parent_hash(), header.extrinsics_root());
+	}
+
+	fn initialise_block_impl(block_number: &System::BlockNumber, parent_hash: &System::Hash, extrinsics_root: &System::Hash) {
+		<system::Module<System>>::initialise(block_number, parent_hash, extrinsics_root);
+		<AllModules as OnInitialise<System::BlockNumber>>::on_initialise(*block_number);
 	}
 
 	fn initial_checks(block: &Block) {
@@ -96,18 +126,35 @@ impl<
 		// any initial checks
 		Self::initial_checks(&block);
 
-		// execute transactions
+		// execute extrinsics
 		let (header, extrinsics) = block.deconstruct();
-		extrinsics.into_iter().for_each(Self::apply_extrinsic_no_note);
-
-		// post-transactional book-keeping.
-		<system::Module<System>>::note_finished_extrinsics();
-		<AllModules as OnFinalise<System::BlockNumber>>::on_finalise(*header.number());
+		Self::execute_extrinsics_with_book_keeping(extrinsics, *header.number());
 
 		// any final checks
 		Self::final_checks(&header);
 	}
 
+	/// Execute all extrinsics like when executing a `block`, but with dropping intial and final checks.
+	pub fn execute_extrinsics_without_checks(block_number: NumberFor<Block>, extrinsics: Vec<Block::Extrinsic>) {
+		// Make the api happy, but maybe we should not set them at all.
+		let parent_hash = <Block::Header as Header>::Hashing::hash(b"parent_hash");
+		let extrinsics_root = <Block::Header as Header>::Hashing::hash(b"extrinsics_root");
+
+		Self::initialise_block_impl(&block_number, &parent_hash, &extrinsics_root);
+
+		// execute extrinsics
+		Self::execute_extrinsics_with_book_keeping(extrinsics, block_number);
+	}
+
+	/// Execute given extrinsics and take care of post-extrinsics book-keeping
+	fn execute_extrinsics_with_book_keeping(extrinsics: Vec<Block::Extrinsic>, block_number: NumberFor<Block>) {
+		extrinsics.into_iter().for_each(Self::apply_extrinsic_no_note);
+
+		// post-extrinsics book-keeping.
+		<system::Module<System>>::note_finished_extrinsics();
+		<AllModules as OnFinalise<System::BlockNumber>>::on_finalise(block_number);
+	}
+
 	/// Finalise the block - it is up the caller to ensure that all header fields are valid
 	/// except state-root.
 	pub fn finalise_block() -> System::Header {
diff --git a/srml/support/src/storage/mod.rs b/srml/support/src/storage/mod.rs
index dec8b2fec80a8..fde0762877874 100644
--- a/srml/support/src/storage/mod.rs
+++ b/srml/support/src/storage/mod.rs
@@ -38,7 +38,7 @@ impl<'a> Input for IncrementalInput<'a> {
 	}
 }
 
- /// Return the value of the item in storage under `key`, or `None` if there is no explicit entry.
+/// Return the value of the item in storage under `key`, or `None` if there is no explicit entry.
 pub fn get<T: Decode + Sized>(key: &[u8]) -> Option<T> {
 	let key = twox_128(key);
 	runtime_io::read_storage(&key[..], &mut [0; 0][..], 0).map(|_| {
diff --git a/srml/system/src/lib.rs b/srml/system/src/lib.rs
index 384c4fb462b1e..c5397345a1e95 100644
--- a/srml/system/src/lib.rs
+++ b/srml/system/src/lib.rs
@@ -324,8 +324,7 @@ impl<T: Trait> Module<T> {
 
 		// <Events<T>> stays to be inspected by the client.
 
-		<T::Header as traits::Header>::new(number, extrinsics_root, storage_root,
-			parent_hash, digest)
+		<T::Header as traits::Header>::new(number, extrinsics_root, storage_root, parent_hash, digest)
 	}
 
 	/// Deposits a log and ensures it matches the blocks log data.