WASM contracts MVP (#5679)

* lifetime issues

* refactor to new 'native env'

* descriptors and such

* wasm mvp continued

* finalized env/ext bindings

* descriptor -> call_args

* inject gas counter

* result processing and engine activation

* tabify some source files

* needs return new

* wasm tests initial

* erradicate warnings

* origin in the descriptor

* update test repo

* payload verification tests

* identity return payload test

* some test description

* dispersion test

* check length here

* suicidal contract

* engine params

* fix typo

* review fixes

* submodule update

* update - purge reserved space

* doc effort

* more review fixes

* fix error message

* fix dependency url

* reorg error handling

* update submodule

* update utils

* update to latest parity-wasm

* tabify

* fix wasm magic header

* update dependencies

* external create and tests

* update to latest tests

* extra trace info

* Update parity-wasm

* update wasm-utils also

* few traces and result handle change

* alter trace content

* fix issues with optimizer, update to latest parity with validator, etc

* static initialization

* license preamble

* update wasm crates and gas costs

* fix grumbles

* bring back lifetime

* fix compilation

.gitmodules

@@ -2,3 +2,6 @@
 	path = ethcore/res/ethereum/tests
 	url = https://github.com/ethereum/tests.git
 	branch = develop
+[submodule "ethcore/res/wasm-tests"]
+	path = ethcore/res/wasm-tests
+	url = https://github.com/paritytech/wasm-tests

Cargo.lock

@@ -57,6 +57,16 @@ dependencies = [
  "syntex_syntax 0.58.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "atty"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "base-x"
 version = "0.2.2"
@@ -119,6 +129,11 @@ name = "bitflags"
 version = "0.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "bitflags"
+version = "0.8.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "bitflags"
 version = "0.9.1"
@@ -173,6 +188,21 @@ dependencies = [
  "multihash 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "clap"
+version = "2.24.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "ansi_term 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "atty 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "bitflags 0.8.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "strsim 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "term_size 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-segmentation 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-width 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "vec_map 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "clippy"
 version = "0.0.103"
@@ -376,6 +406,7 @@ dependencies = [
  "native-contracts 0.1.0",
  "num 0.1.32 (registry+https://github.com/rust-lang/crates.io-index)",
  "num_cpus 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-wasm 0.12.1 (git+http://github.com/nikvolf/parity-wasm)",
  "rand 0.3.14 (registry+https://github.com/rust-lang/crates.io-index)",
  "rlp 0.2.0",
  "rust-crypto 0.2.36 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -385,6 +416,7 @@ dependencies = [
  "stats 0.1.0",
  "time 0.1.35 (registry+https://github.com/rust-lang/crates.io-index)",
  "transient-hashmap 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "wasm-utils 0.1.0 (git+https://github.com/paritytech/wasm-utils)",
 ]
 
 [[package]]
@@ -1848,6 +1880,16 @@ dependencies = [
  "target_info 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "parity-wasm"
+version = "0.12.1"
+source = "git+http://github.com/nikvolf/parity-wasm#98311ec7333e0d3dc9e45c9df673cc79e41acb83"
+dependencies = [
+ "byteorder 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parking_lot 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "parity-wordlist"
 version = "1.0.1"
@@ -2523,6 +2565,16 @@ dependencies = [
  "winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "term_size"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "termios"
 version = "0.2.2"
@@ -2743,6 +2795,11 @@ name = "unicode-segmentation"
 version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "unicode-width"
+version = "0.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "unicode-xid"
 version = "0.0.4"
@@ -2784,6 +2841,11 @@ name = "utf8-ranges"
 version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "vec_map"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "vecio"
 version = "0.1.0"
@@ -2807,6 +2869,18 @@ name = "void"
 version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "wasm-utils"
+version = "0.1.0"
+source = "git+https://github.com/paritytech/wasm-utils#357a5deed635938e79553227bfab976959ca3523"
+dependencies = [
+ "clap 2.24.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "env_logger 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "lazy_static 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-wasm 0.12.1 (git+http://github.com/nikvolf/parity-wasm)",
+]
+
 [[package]]
 name = "winapi"
 version = "0.2.8"
@@ -2882,6 +2956,7 @@ dependencies = [
 "checksum app_dirs 1.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "b7d1c0d48a81bbb13043847f957971f4d87c81542d80ece5e84ba3cba4058fd4"
 "checksum arrayvec 0.3.20 (registry+https://github.com/rust-lang/crates.io-index)" = "d89f1b0e242270b5b797778af0c8d182a1a2ccac5d8d6fadf414223cc0fab096"
 "checksum aster 0.41.0 (registry+https://github.com/rust-lang/crates.io-index)" = "4ccfdf7355d9db158df68f976ed030ab0f6578af811f5a7bb6dcf221ec24e0e0"
+"checksum atty 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "d912da0db7fa85514874458ca3651fe2cddace8d0b0505571dbdcd41ab490159"
 "checksum base-x 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "2f59103b47307f76e03bef1633aec7fa9e29bfb5aa6daf5a334f94233c71f6c1"
 "checksum base32 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "1b9605ba46d61df0410d8ac686b0007add8172eba90e8e909c347856fe794d8c"
 "checksum bigint 3.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "1d0673c930652d3d4d6dcd5c45b5db4fa5f8f33994d7323618c43c083b223e8c"
@@ -2891,6 +2966,7 @@ dependencies = [
 "checksum bit-vec 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)" = "5b97c2c8e8bbb4251754f559df8af22fb264853c7d009084a576cdf12565089d"
 "checksum bitflags 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "4f67931368edf3a9a51d29886d245f1c3db2f1ef0dcc9e35ff70341b78c10d23"
 "checksum bitflags 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "aad18937a628ec6abcd26d1489012cc0e18c21798210f491af69ded9b881106d"
+"checksum bitflags 0.8.2 (registry+https://github.com/rust-lang/crates.io-index)" = "1370e9fc2a6ae53aea8b7a5110edbd08836ed87c88736dfabccade1c2b44bff4"
 "checksum bitflags 0.9.1 (registry+https://github.com/rust-lang/crates.io-index)" = "4efd02e230a02e18f92fc2735f44597385ed02ad8f831e7c1c1156ee5e1ab3a5"
 "checksum blastfig 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "09640e0509d97d5cdff03a9f5daf087a8e04c735c3b113a75139634a19cfc7b2"
 "checksum bloomchain 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3f421095d2a76fc24cd3fb3f912b90df06be7689912b1bdb423caefae59c258d"
@@ -2899,6 +2975,7 @@ dependencies = [
 "checksum bytes 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)" = "8b24f16593f445422331a5eed46b72f7f171f910fead4f2ea8f17e727e9c5c14"
 "checksum cfg-if 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "de1e760d7b6535af4241fca8bd8adf68e2e7edacc6b29f5d399050c5e48cf88c"
 "checksum cid 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "34aa7da06f10541fbca6850719cdaa8fa03060a5d2fb33840f149cf8133a00c7"
+"checksum clap 2.24.2 (registry+https://github.com/rust-lang/crates.io-index)" = "6b8f69e518f967224e628896b54e41ff6acfb4dcfefc5076325c36525dac900f"
 "checksum clippy 0.0.103 (registry+https://github.com/rust-lang/crates.io-index)" = "5b4fabf979ddf6419a313c1c0ada4a5b95cfd2049c56e8418d622d27b4b6ff32"
 "checksum clippy_lints 0.0.103 (registry+https://github.com/rust-lang/crates.io-index)" = "ce96ec05bfe018a0d5d43da115e54850ea2217981ff0f2e462780ab9d594651a"
 "checksum cookie 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "d53b80dde876f47f03cda35303e368a79b91c70b0d65ecba5fd5280944a08591"
@@ -3003,6 +3080,7 @@ dependencies = [
 "checksum parity-dapps-glue 1.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "e1d06f6ee0fda786df3784a96ee3f0629f529b91cbfb7d142f6410e6bcd1ce2c"
 "checksum parity-tokio-ipc 0.1.5 (git+https://github.com/nikvolf/parity-tokio-ipc)" = "<none>"
 "checksum parity-ui-precompiled 1.4.0 (git+https://github.com/paritytech/js-precompiled.git)" = "<none>"
+"checksum parity-wasm 0.12.1 (git+http://github.com/nikvolf/parity-wasm)" = "<none>"
 "checksum parity-wordlist 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "52142d717754f7ff7ef0fc8da1bdce4f302dd576fb9bf8b727d6a5fdef33348d"
 "checksum parking_lot 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "aebb68eebde2c99f89592d925288600fde220177e46b5c9a91ca218d245aeedf"
 "checksum parking_lot_core 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "fb1b97670a2ffadce7c397fb80a3d687c4f3060140b885621ef1653d0e5d5068"
@@ -3080,6 +3158,7 @@ dependencies = [
 "checksum target_info 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "c63f48baada5c52e65a29eef93ab4f8982681b67f9e8d29c7b05abcfec2b9ffe"
 "checksum tempdir 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)" = "87974a6f5c1dfb344d733055601650059a3363de2a6104819293baff662132d6"
 "checksum term 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)" = "d168af3930b369cfe245132550579d47dfd873d69470755a19c2c6568dbbd989"
+"checksum term_size 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "e2b6b55df3198cc93372e85dd2ed817f0e38ce8cc0f22eb32391bfad9c4bf209"
 "checksum termios 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "d5d9cf598a6d7ce700a4e6a9199da127e6819a61e64b68609683cc9a01b5683a"
 "checksum thread-id 3.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "4437c97558c70d129e40629a5b385b3fb1ffac301e63941335e4d354081ec14a"
 "checksum thread_local 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "c85048c6260d17cf486ceae3282d9fb6b90be220bf5b28c400f5485ffc29f0c7"
@@ -3103,15 +3182,18 @@ dependencies = [
 "checksum unicode-bidi 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "c1f7ceb96afdfeedee42bade65a0d585a6a0106f681b6749c8ff4daa8df30b3f"
 "checksum unicode-normalization 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "26643a2f83bac55f1976fb716c10234485f9202dcd65cfbdf9da49867b271172"
 "checksum unicode-segmentation 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "18127285758f0e2c6cf325bb3f3d138a12fee27de4f23e146cd6a179f26c2cf3"
+"checksum unicode-width 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)" = "bf3a113775714a22dcb774d8ea3655c53a32debae63a063acc00a91cc586245f"
 "checksum unicode-xid 0.0.4 (registry+https://github.com/rust-lang/crates.io-index)" = "8c1f860d7d29cf02cb2f3f359fd35991af3d30bac52c57d265a3c461074cb4dc"
 "checksum unreachable 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "1f2ae5ddb18e1c92664717616dd9549dde73f539f01bd7b77c2edb2446bdff91"
 "checksum untrusted 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "6b65243989ef6aacd9c0d6bd2b822765c3361d8ed352185a6f3a41f3a718c673"
 "checksum url 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "afe9ec54bc4db14bc8744b7fed060d785ac756791450959b2248443319d5b119"
 "checksum user32-sys 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "4ef4711d107b21b410a3a974b1204d9accc8b10dad75d8324b5d755de1617d47"
 "checksum utf8-ranges 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "662fab6525a98beff2921d7f61a39e7d59e0b425ebc7d0d9e66d316e55124122"
+"checksum vec_map 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)" = "887b5b631c2ad01628bbbaa7dd4c869f80d3186688f8d0b6f58774fbe324988c"
 "checksum vecio 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "0795a11576d29ae80525a3fda315bf7b534f8feb9d34101e5fe63fb95bb2fd24"
 "checksum vergen 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "56b639f935488eb40f06d17c3e3bcc3054f6f75d264e187b1107c8d1cba8d31c"
 "checksum void 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "6a02e4885ed3bc0f2de90ea6dd45ebcbb66dacffe03547fadbb0eeae2770887d"
+"checksum wasm-utils 0.1.0 (git+https://github.com/paritytech/wasm-utils)" = "<none>"
 "checksum winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "167dc9d6949a9b857f3451275e911c3f44255842c1f7a76f33c55103a909087a"
 "checksum winapi-build 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "2d315eee3b34aca4797b2da6b13ed88266e6d612562a0c46390af8299fc699bc"
 "checksum ws 0.7.1 (git+https://github.com/tomusdrw/ws-rs)" = "<none>"

ethcore/Cargo.toml

@@ -52,6 +52,8 @@ semver = "0.6"
 stats = { path = "../util/stats" }
 time = "0.1"
 transient-hashmap = "0.4"
+parity-wasm = { git = "https://github.com/nikvolf/parity-wasm" }
+wasm-utils = { git = "https://github.com/paritytech/wasm-utils" }
 
 [dev-dependencies]
 native-contracts = { path = "native_contracts", features = ["test_contracts"] }

ethcore/res/wasm-tests

@@ -0,0 +1 @@
+Subproject commit 9ed6304313fa949ed92aa0570fb2bc759fb6dc58

ethcore/src/action_params.rs

@@ -39,6 +39,16 @@ impl ActionValue {
 			ActionValue::Transfer(x) | ActionValue::Apparent(x) => x
 		}
 	}
+
+	/// Returns the transfer action value of the U256-convertable raw value
+	pub fn transfer<T: Into<U256>>(transfer_value: T) -> ActionValue {
+		ActionValue::Transfer(transfer_value.into())
+	}
+
+	/// Returns the apparent action value of the U256-convertable raw value
+	pub fn apparent<T: Into<U256>>(apparent_value: T) -> ActionValue {
+		ActionValue::Apparent(apparent_value.into())		
+	}
 }
 
 // TODO: should be a trait, possible to avoid cloning everything from a Transaction(/View).

ethcore/src/engines/mod.rs

@@ -376,6 +376,11 @@ pub trait Engine : Sync + Send {
 		self.snapshot_components().is_some()
 	}
 
+	/// If this engine supports wasm contracts.
+	fn supports_wasm(&self) -> bool {
+		self.params().wasm
+	}
+
 	/// Returns new contract address generation scheme at given block number.
 	fn create_address_scheme(&self, number: BlockNumber) -> CreateContractAddress {
 		if number >= self.params().eip86_transition {

ethcore/src/evm/evm.rs

@@ -21,6 +21,7 @@ use util::{U128, U256, U512, trie};
 use action_params::ActionParams;
 use evm::Ext;
 use builtin;
+use super::wasm;
 
 /// Evm errors.
 #[derive(Debug, Clone, PartialEq)]
@@ -66,6 +67,8 @@ pub enum Error {
 	MutableCallInStaticContext,
 	/// Likely to cause consensus issues.
 	Internal(String),
+	/// Wasm runtime error
+	Wasm(String),
 }
 
 impl From<Box<trie::TrieError>> for Error {
@@ -80,6 +83,12 @@ impl From<builtin::Error> for Error {
 	}
 }
 
+impl From<wasm::RuntimeError> for Error {
+	fn from(err: wasm::RuntimeError) -> Self {
+		Error::Wasm(format!("Runtime error: {:?}", err))
+	}
+}
+
 impl fmt::Display for Error {
 	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 		use self::Error::*;
@@ -92,6 +101,7 @@ impl fmt::Display for Error {
 			BuiltIn(name) => write!(f, "Built-in failed: {}", name),
 			Internal(ref msg) => write!(f, "Internal error: {}", msg),
 			MutableCallInStaticContext => write!(f, "Mutable call in static context"),
+			Wasm(ref msg) => write!(f, "Internal error: {}", msg),
 		}
 	}
 }

ethcore/src/evm/mod.rs

@@ -22,6 +22,7 @@ pub mod interpreter;
 #[macro_use]
 pub mod factory;
 pub mod schedule;
+pub mod wasm;
 
 mod vmtype;
 mod instructions;

ethcore/src/evm/tests.rs

@@ -39,13 +39,13 @@ pub enum FakeCallType {
 
 #[derive(PartialEq, Eq, Hash, Debug)]
 pub struct FakeCall {
-	call_type: FakeCallType,
+	pub call_type: FakeCallType,
-	gas: U256,
+	pub gas: U256,
-	sender_address: Option<Address>,
+	pub sender_address: Option<Address>,
-	receive_address: Option<Address>,
+	pub receive_address: Option<Address>,
-	value: Option<U256>,
+	pub value: Option<U256>,
-	data: Bytes,
+	pub data: Bytes,
-	code_address: Option<Address>,
+	pub code_address: Option<Address>,
 }
 
 /// Fake externalities test structure.
@@ -53,17 +53,17 @@ pub struct FakeCall {
 /// Can't do recursive calls.
 #[derive(Default)]
 pub struct FakeExt {
+	pub store: HashMap<H256, H256>,
+	pub suicides: HashSet<Address>,
+	pub calls: HashSet<FakeCall>,
 	sstore_clears: usize,
 	depth: usize,
-	store: HashMap<H256, H256>,
 	blockhashes: HashMap<U256, H256>,
 	codes: HashMap<Address, Arc<Bytes>>,
 	logs: Vec<FakeLogEntry>,
-	_suicides: HashSet<Address>,
 	info: EnvInfo,
 	schedule: Schedule,
 	balances: HashMap<Address, U256>,
-	calls: HashSet<FakeCall>,
 }
 
 // similar to the normal `finalize` function, but ignoring NeedsReturn.
@@ -173,8 +173,9 @@ impl Ext for FakeExt {
 		unimplemented!();
 	}
 
-	fn suicide(&mut self, _refund_address: &Address) -> evm::Result<()> {
+	fn suicide(&mut self, refund_address: &Address) -> evm::Result<()> {
-		unimplemented!();
+		self.suicides.insert(refund_address.clone());
+		Ok(())
 	}
 
 	fn schedule(&self) -> &Schedule {

ethcore/src/evm/wasm/call_args.rs

@@ -0,0 +1,62 @@
+// Copyright 2015-2017 Parity Technologies (UK) Ltd.
+// This file is part of Parity.
+
+// Parity 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.
+
+// Parity 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 Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Wasm evm call arguments helper
+
+use util::{U256, H160};
+
+/// Input part of the wasm call descriptor
+pub struct CallArgs {
+	/// Receiver of the transaction
+	pub address: [u8; 20],
+
+	/// Sender of the transaction
+	pub sender: [u8; 20],
+
+	/// Original transaction initiator
+	pub origin: [u8; 20],
+
+	/// Transfer value
+	pub value: [u8; 32],
+
+	/// call/create params
+	pub data: Vec<u8>,
+}
+
+impl CallArgs {
+	/// New contract call payload with known parameters
+	pub fn new(address: H160, sender: H160, origin: H160, value: U256, data: Vec<u8>) -> Self {
+		let mut descriptor = CallArgs {
+			address: [0u8; 20],
+			sender: [0u8; 20],
+			origin: [0u8; 20],
+			value: [0u8; 32],
+			data: data,
+		};
+
+		descriptor.address.copy_from_slice(&*address);
+		descriptor.sender.copy_from_slice(&*sender);
+		descriptor.origin.copy_from_slice(&*origin);
+		value.to_big_endian(&mut descriptor.value);
+
+		descriptor
+	}
+
+	/// Total call payload length in linear memory
+	pub fn len(&self) -> u32 {
+		self.data.len() as u32 + 92
+	}
+}

ethcore/src/evm/wasm/env.rs

@@ -0,0 +1,119 @@
+// Copyright 2015-2017 Parity Technologies (UK) Ltd.
+// This file is part of Parity.
+
+// Parity 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.
+
+// Parity 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 Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Wasm env module bindings 
+
+use parity_wasm::elements::ValueType::*;
+use parity_wasm::interpreter::UserFunctionDescriptor;
+use parity_wasm::interpreter::UserFunctionDescriptor::*;
+
+pub const SIGNATURES: &'static [UserFunctionDescriptor] = &[
+	Static(
+		"_storage_read",
+		&[I32; 2],
+		Some(I32),
+	),
+	Static(
+		"_storage_write",
+		&[I32; 2],
+		Some(I32),
+	),
+	Static(
+		"_malloc",
+		&[I32],
+		Some(I32),
+	),
+	Static(
+		"_free",
+		&[I32],
+		None,
+	),
+	Static(
+		"gas",
+		&[I32],
+		None,
+	),
+	Static(
+		"_debug",
+		&[I32; 2],
+		None,
+	),
+	Static(
+		"_suicide",
+		&[I32],
+		None,
+	),
+	Static(
+		"_create",
+		&[I32; 4],
+		Some(I32),
+	),
+	Static(
+		"abort",
+		&[I32],
+		None,
+	),
+	Static(
+		"_abort",
+		&[],
+		None,
+	),
+	Static(
+		"invoke_vii",
+		&[I32; 3],
+		None,
+	),
+	Static(
+		"invoke_vi",
+		&[I32; 2],
+		None,
+	),
+	Static(
+		"invoke_v",
+		&[I32],
+		None,
+	),
+	Static(
+		"invoke_iii",
+		&[I32; 3],
+		Some(I32),
+	),
+	Static(
+		"___resumeException",
+		&[I32],
+		None,
+	),
+	Static(
+		"_rust_begin_unwind",
+		&[I32; 4],
+		None,
+	),
+	Static(
+		"___cxa_find_matching_catch_2",
+		&[],
+		Some(I32),
+	),
+	Static(
+		"___gxx_personality_v0",
+		&[I32; 6],
+		Some(I32),
+	),
+	Static(
+		"_emscripten_memcpy_big",
+		&[I32; 3],
+		Some(I32),
+	)
+];

ethcore/src/evm/wasm/mod.rs

@@ -0,0 +1,159 @@
+// Copyright 2015-2017 Parity Technologies (UK) Ltd.
+// This file is part of Parity.
+
+// Parity 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.
+
+// Parity 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 Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Wasm Interpreter
+
+mod runtime;
+mod ptr;
+mod call_args;
+mod result;
+#[cfg(test)]
+mod tests;
+mod env;
+
+use std::sync::Arc;
+
+const DEFAULT_STACK_SPACE: u32 = 5 * 1024 * 1024;
+
+use parity_wasm::{interpreter, elements};
+use parity_wasm::interpreter::ModuleInstanceInterface;
+use wasm_utils;
+
+use evm::{self, GasLeft, ReturnData};
+use action_params::ActionParams;
+use self::runtime::Runtime;
+
+pub use self::runtime::Error as RuntimeError;
+
+const DEFAULT_RESULT_BUFFER: usize = 1024;
+
+/// Wasm interpreter instance
+pub struct WasmInterpreter {
+	program: interpreter::ProgramInstance,
+	result: Vec<u8>,
+}
+
+impl WasmInterpreter {
+	/// New wasm interpreter instance
+	pub fn new() -> Result<WasmInterpreter, RuntimeError> {
+		Ok(WasmInterpreter {
+			program: interpreter::ProgramInstance::new()?,
+			result: Vec::with_capacity(DEFAULT_RESULT_BUFFER),
+		})
+	}
+}
+
+impl evm::Evm for WasmInterpreter {
+
+	fn exec(&mut self, params: ActionParams, ext: &mut evm::Ext) -> evm::Result<GasLeft> {
+		use parity_wasm::elements::Deserialize;
+
+		let code = params.code.expect("exec is only called on contract with code; qed");
+
+		trace!(target: "wasm", "Started wasm interpreter with code.len={:?}", code.len());
+
+		let env_instance = self.program.module("env")
+			// prefer explicit panic here
+			.expect("Wasm program to contain env module");
+
+		let env_memory = env_instance.memory(interpreter::ItemIndex::Internal(0))
+			// prefer explicit panic here
+			.expect("Linear memory to exist in wasm runtime");
+
+		if params.gas > ::std::u64::MAX.into() {
+			return Err(evm::Error::Wasm("Wasm interpreter cannot run contracts with gas >= 2^64".to_owned()));
+		}
+		
+		let mut runtime = Runtime::with_params(
+			ext,
+			env_memory,
+			DEFAULT_STACK_SPACE,
+			params.gas.low_u64(),
+		);
+
+		let mut cursor = ::std::io::Cursor::new(&*code);
+
+		let contract_module = wasm_utils::inject_gas_counter(
+			elements::Module::deserialize(
+				&mut cursor
+			).map_err(|err| {
+				evm::Error::Wasm(format!("Error deserializing contract code ({:?})", err))
+			})?
+		);
+
+		let d_ptr = runtime.write_descriptor(
+			call_args::CallArgs::new(
+				params.address,
+				params.sender,
+				params.origin,
+				params.value.value(),
+				params.data.unwrap_or(Vec::with_capacity(0)),
+			)
+		)?;
+
+		{
+			let execution_params = interpreter::ExecutionParams::with_external(
+				"env".into(), 
+				Arc::new(
+					interpreter::env_native_module(env_instance, native_bindings(&mut runtime))
+						.map_err(|err| {
+							// todo: prefer explicit panic here also?
+							evm::Error::Wasm(format!("Error instantiating native bindings: {:?}", err))
+						})?
+				)
+			).add_argument(interpreter::RuntimeValue::I32(d_ptr.as_raw() as i32));
+		
+			let module_instance = self.program.add_module("contract", contract_module, Some(&execution_params.externals))
+				.map_err(|err| {
+					trace!(target: "wasm", "Error adding contract module: {:?}", err);
+					evm::Error::from(RuntimeError::Interpreter(err))
+				})?;
+
+			module_instance.execute_export("_call", execution_params)
+				.map_err(|err| {
+					trace!(target: "wasm", "Error executing contract: {:?}", err);
+					evm::Error::from(RuntimeError::Interpreter(err))
+				})?;
+		}
+
+		let result = result::WasmResult::new(d_ptr);
+		if result.peek_empty(&*runtime.memory())? {
+			trace!(target: "wasm", "Contract execution result is empty.");
+			Ok(GasLeft::Known(runtime.gas_left()?.into()))
+		} else {
+			self.result.clear();
+			// todo: use memory views to avoid copy
+			self.result.extend(result.pop(&*runtime.memory())?);
+			let len = self.result.len();
+			Ok(GasLeft::NeedsReturn { 
+				gas_left: runtime.gas_left()?.into(), 
+				data: ReturnData::new(
+					::std::mem::replace(&mut self.result, Vec::with_capacity(DEFAULT_RESULT_BUFFER)), 
+					0, 
+					len,
+				),
+				apply_state: true,
+			})
+		}
+	}
+}
+
+fn native_bindings<'a>(runtime: &'a mut Runtime) -> interpreter::UserFunctions<'a> {
+	interpreter::UserFunctions {
+		executor: runtime,
+		functions: ::std::borrow::Cow::from(env::SIGNATURES),
+	}
+}

ethcore/src/evm/wasm/ptr.rs

@@ -0,0 +1,52 @@
+// Copyright 2015-2017 Parity Technologies (UK) Ltd.
+// This file is part of Parity.
+
+// Parity 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.
+
+// Parity 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 Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Wasm bound-checked ptr
+
+use parity_wasm::interpreter;
+
+/// Bound-checked wrapper for webassembly memory 
+pub struct WasmPtr(u32);
+
+/// Error in bound check
+#[derive(Debug)]
+pub enum Error {
+	AccessViolation,
+}
+
+impl From<u32> for WasmPtr {
+	fn from(raw: u32) -> Self { 
+		WasmPtr(raw)
+	}
+}
+
+impl WasmPtr {
+	// todo: use memory view when they are on
+	/// Check memory range and return data with given length starting from the current pointer value
+	pub fn slice(&self, len: u32, mem: &interpreter::MemoryInstance) -> Result<Vec<u8>, Error> {
+		mem.get(self.0, len as usize).map_err(|_| Error::AccessViolation)
+	}
+
+	// todo: maybe 2gb limit can be enhanced
+	/// Convert i32 from wasm stack to the wrapped pointer
+	pub fn from_i32(raw_ptr: i32) -> Result<Self, Error> {
+		if raw_ptr < 0 { return Err(Error::AccessViolation); }
+		Ok(WasmPtr(raw_ptr as u32))
+	}
+
+	/// Return pointer raw value
+	pub fn as_raw(&self) -> u32 { self.0 }
+}

ethcore/src/evm/wasm/result.rs

@@ -0,0 +1,51 @@
+// Copyright 2015-2017 Parity Technologies (UK) Ltd.
+// This file is part of Parity.
+
+// Parity 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.
+
+// Parity 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 Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Wasm evm results helper
+
+use byteorder::{LittleEndian, ByteOrder};
+
+use parity_wasm::interpreter;
+
+use super::ptr::WasmPtr;
+use super::runtime::Error as RuntimeError;
+
+/// Wrapper for wasm contract call result
+pub struct WasmResult {
+	ptr: WasmPtr,
+}
+
+impl WasmResult {
+	/// New call result from given ptr
+	pub fn new(descriptor_ptr: WasmPtr) -> WasmResult {
+		WasmResult { ptr: descriptor_ptr }
+	}
+
+	/// Check if the result contains any data
+	pub fn peek_empty(&self, mem: &interpreter::MemoryInstance) -> Result<bool, RuntimeError> {
+		let result_len = LittleEndian::read_u32(&self.ptr.slice(16, mem)?[12..16]);
+		Ok(result_len == 0)
+	}
+
+	/// Consume the result ptr and return the actual data from wasm linear memory
+	pub fn pop(self, mem: &interpreter::MemoryInstance) -> Result<Vec<u8>, RuntimeError> {
+		let result_ptr = LittleEndian::read_u32(&self.ptr.slice(16, mem)?[8..12]);
+		let result_len = LittleEndian::read_u32(&self.ptr.slice(16, mem)?[12..16]);
+		trace!(target: "wasm", "contract result: {} bytes at @{}", result_len, result_ptr);
+
+		Ok(mem.get(result_ptr, result_len as usize)?)
+	}
+}

ethcore/src/evm/wasm/runtime.rs

@@ -0,0 +1,356 @@
+// Copyright 2015-2017 Parity Technologies (UK) Ltd.
+// This file is part of Parity.
+
+// Parity 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.
+
+// Parity 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 Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Wasm evm program runtime intstance
+
+use std::sync::Arc;
+
+use byteorder::{LittleEndian, ByteOrder};
+
+use evm;
+
+use parity_wasm::interpreter;
+use util::{Address, H256, U256};
+
+use super::ptr::{WasmPtr, Error as PtrError};
+use super::call_args::CallArgs;
+
+/// Wasm runtime error
+#[derive(Debug)]
+pub enum Error {
+	/// Storage error
+	Storage,
+	/// Allocator error
+	Allocator,
+	/// Invalid gas state during the call
+	InvalidGasState,
+	/// Memory access violation
+	AccessViolation,
+	/// Interpreter runtime error
+	Interpreter(interpreter::Error),
+}
+
+impl From<interpreter::Error> for Error {
+	fn from(err: interpreter::Error) -> Self {
+		Error::Interpreter(err)
+	}
+}
+
+impl From<PtrError> for Error {
+	fn from(err: PtrError) -> Self {
+		match err {
+			PtrError::AccessViolation => Error::AccessViolation,
+		}
+	}
+}
+
+/// Runtime enviroment data for wasm contract execution
+pub struct Runtime<'a> {
+	gas_counter: u64,
+	gas_limit: u64,
+	dynamic_top: u32,
+	ext: &'a mut evm::Ext,
+	memory: Arc<interpreter::MemoryInstance>,
+}
+
+impl<'a> Runtime<'a> {
+	/// New runtime for wasm contract with specified params
+	pub fn with_params<'b>(
+		ext: &'b mut evm::Ext,
+		memory: Arc<interpreter::MemoryInstance>, 
+		stack_space: u32, 
+		gas_limit: u64,
+	) -> Runtime<'b> {
+		Runtime {
+			gas_counter: 0,
+			gas_limit: gas_limit,
+			dynamic_top: stack_space,
+			memory: memory,
+			ext: ext,
+		}
+	}
+
+	/// Write to the storage from wasm memory
+	pub fn storage_write(&mut self, context: interpreter::CallerContext) 
+		-> Result<Option<interpreter::RuntimeValue>, interpreter::Error>
+	{
+		let mut context = context;
+		let val = self.pop_h256(&mut context)?;
+		let key = self.pop_h256(&mut context)?;
+		trace!(target: "wasm", "storage_write: value {} at @{}", &val, &key);
+
+		self.ext.set_storage(key, val)
+			.map_err(|_| interpreter::Error::Trap("Storage update error".to_owned()))?;
+
+		Ok(Some(0i32.into()))
+	}
+
+	/// Read from the storage to wasm memory
+	pub fn storage_read(&mut self, context: interpreter::CallerContext) 
+		-> Result<Option<interpreter::RuntimeValue>, interpreter::Error>
+	{
+		let mut context = context;
+		let val_ptr = context.value_stack.pop_as::<i32>()?;
+		let key = self.pop_h256(&mut context)?;		
+
+		let val = self.ext.storage_at(&key)
+			.map_err(|_| interpreter::Error::Trap("Storage read error".to_owned()))?;
+
+		self.memory.set(val_ptr as u32, &*val)?;
+
+		Ok(Some(0.into()))
+	}
+
+	/// Pass suicide to state runtime
+	pub fn suicide(&mut self, context: interpreter::CallerContext) 
+		-> Result<Option<interpreter::RuntimeValue>, interpreter::Error>
+	{
+		let mut context = context;
+		let refund_address = self.pop_address(&mut context)?;	
+
+		self.ext.suicide(&refund_address)
+			.map_err(|_| interpreter::Error::Trap("Suicide error".to_owned()))?;
+
+		Ok(None)
+	}
+
+	/// Invoke create in the state runtime
+	pub fn create(&mut self, context: interpreter::CallerContext) 
+		-> Result<Option<interpreter::RuntimeValue>, interpreter::Error>
+	{
+		//
+		// method signature:
+		//   fn create(endowment: *const u8, code_ptr: *const u8, code_len: u32, result_ptr: *mut u8) -> i32;
+		//
+
+		trace!(target: "wasm", "runtime: create contract");
+		let mut context = context;
+		let result_ptr = context.value_stack.pop_as::<i32>()? as u32;
+		trace!(target: "wasm", "    result_ptr: {:?}", result_ptr);		
+		let code_len = context.value_stack.pop_as::<i32>()? as u32;
+		trace!(target: "wasm", "    code_len: {:?}", code_len);		
+		let code_ptr = context.value_stack.pop_as::<i32>()? as u32;
+		trace!(target: "wasm", "    code_ptr: {:?}", code_ptr);		
+		let endowment = self.pop_u256(&mut context)?;
+		trace!(target: "wasm", "    val: {:?}", endowment);
+
+		let code = self.memory.get(code_ptr, code_len as usize)?;
+
+		let gas_left = self.gas_left()
+			.map_err(|_| interpreter::Error::Trap("Gas state error".to_owned()))?
+			.into();
+		
+		match self.ext.create(&gas_left, &endowment, &code, evm::CreateContractAddress::FromSenderAndCodeHash) {
+			evm::ContractCreateResult::Created(address, gas_left) => {
+				self.memory.set(result_ptr, &*address)?;
+				self.gas_counter = self.gas_limit - gas_left.low_u64();
+				trace!(target: "wasm", "runtime: create contract success (@{:?})", address);
+				Ok(Some(0i32.into()))
+			},
+			evm::ContractCreateResult::Failed => {
+				trace!(target: "wasm", "runtime: create contract fail");
+				Ok(Some((-1i32).into()))
+			}
+		}
+	}
+
+	/// Allocate memory using the wasm stack params
+	pub fn malloc(&mut self, context: interpreter::CallerContext) 
+		-> Result<Option<interpreter::RuntimeValue>, interpreter::Error>
+	{
+		let amount = context.value_stack.pop_as::<i32>()? as u32;
+		let previous_top = self.dynamic_top;
+		self.dynamic_top = previous_top + amount;
+		Ok(Some((previous_top as i32).into()))
+	}
+
+	/// Allocate memory in wasm memory instance
+	pub fn alloc(&mut self, amount: u32) -> Result<u32, Error> {
+		let previous_top = self.dynamic_top;
+		self.dynamic_top = previous_top + amount;
+		Ok(previous_top.into())
+	}
+
+	/// Report gas cost with the params passed in wasm stack
+	fn gas(&mut self, context: interpreter::CallerContext) 
+		-> Result<Option<interpreter::RuntimeValue>, interpreter::Error> 
+	{
+		let amount = context.value_stack.pop_as::<i32>()? as u64;
+		if self.charge_gas(amount) {
+			Ok(None)
+		} else {
+			Err(interpreter::Error::Trap(format!("Gas exceeds limits of {}", self.gas_limit)))			
+		}
+	}
+
+	fn charge_gas(&mut self, amount: u64) -> bool {
+		let prev = self.gas_counter;
+		if prev + amount > self.gas_limit {
+			// exceeds gas
+			false
+		} else {
+			self.gas_counter = prev + amount;
+			true
+		}		
+	}
+
+	fn h256_at(&self, ptr: WasmPtr) -> Result<H256, interpreter::Error> {
+		Ok(H256::from_slice(&ptr.slice(32, &*self.memory)
+			.map_err(|_| interpreter::Error::Trap("Memory access violation".to_owned()))?
+		))	
+	}
+
+	fn pop_h256(&self, context: &mut interpreter::CallerContext) -> Result<H256, interpreter::Error> {
+		let ptr = WasmPtr::from_i32(context.value_stack.pop_as::<i32>()?)
+			.map_err(|_| interpreter::Error::Trap("Memory access violation".to_owned()))?;
+		self.h256_at(ptr)
+	}
+
+	fn pop_u256(&self, context: &mut interpreter::CallerContext) -> Result<U256, interpreter::Error> {
+		let ptr = WasmPtr::from_i32(context.value_stack.pop_as::<i32>()?)
+			.map_err(|_| interpreter::Error::Trap("Memory access violation".to_owned()))?;
+		self.h256_at(ptr).map(Into::into)
+	}
+
+	fn address_at(&self, ptr: WasmPtr) -> Result<Address, interpreter::Error> {
+		Ok(Address::from_slice(&ptr.slice(20, &*self.memory)
+			.map_err(|_| interpreter::Error::Trap("Memory access violation".to_owned()))?
+		))	
+	}
+
+	fn pop_address(&self, context: &mut interpreter::CallerContext) -> Result<Address, interpreter::Error> {
+		let ptr = WasmPtr::from_i32(context.value_stack.pop_as::<i32>()?)
+			.map_err(|_| interpreter::Error::Trap("Memory access violation".to_owned()))?;
+		self.address_at(ptr)
+	}
+
+	fn user_trap(&mut self, _context: interpreter::CallerContext) 
+		-> Result<Option<interpreter::RuntimeValue>, interpreter::Error> 
+	{
+		Err(interpreter::Error::Trap("unknown trap".to_owned()))
+	}
+
+	fn user_noop(&mut self, 
+		_context: interpreter::CallerContext
+	) -> Result<Option<interpreter::RuntimeValue>, interpreter::Error> {
+		Ok(None)
+	}
+
+	/// Write call descriptor to wasm memory
+	pub fn write_descriptor(&mut self, call_args: CallArgs) -> Result<WasmPtr, Error> {
+		let d_ptr = self.alloc(16)?;
+
+		let args_len = call_args.len();
+		let args_ptr = self.alloc(args_len)?;
+
+		// write call descriptor
+		// call descriptor is [args_ptr, args_len, return_ptr, return_len]
+		//   all are 4 byte length, last 2 are zeroed
+		let mut d_buf = [0u8; 16];
+		LittleEndian::write_u32(&mut d_buf[0..4], args_ptr);
+		LittleEndian::write_u32(&mut d_buf[4..8], args_len);
+		self.memory.set(d_ptr, &d_buf)?;
+
+		// write call args to memory
+		self.memory.set(args_ptr, &call_args.address)?;
+		self.memory.set(args_ptr+20, &call_args.sender)?;
+		self.memory.set(args_ptr+40, &call_args.origin)?;
+		self.memory.set(args_ptr+60, &call_args.value)?;
+		self.memory.set(args_ptr+92, &call_args.data)?;
+		
+		Ok(d_ptr.into())
+	}
+
+	fn debug_log(&mut self, context: interpreter::CallerContext) 
+			-> Result<Option<interpreter::RuntimeValue>, interpreter::Error> 
+	{
+		let msg_len = context.value_stack.pop_as::<i32>()? as u32;
+		let msg_ptr = context.value_stack.pop_as::<i32>()? as u32;
+		
+		let msg = String::from_utf8(self.memory.get(msg_ptr, msg_len as usize)?)
+			.map_err(|_| interpreter::Error::Trap("Debug log utf-8 decoding error".to_owned()))?;
+
+		trace!(target: "wasm", "Contract debug message: {}", msg);
+
+		Ok(None)
+	}
+
+	/// Query current gas left for execution
+	pub fn gas_left(&self) -> Result<u64, Error> {
+		if self.gas_counter > self.gas_limit { return Err(Error::InvalidGasState); }
+		Ok(self.gas_limit - self.gas_counter)
+	}
+
+	/// Shared memory reference
+	pub fn memory(&self) -> &interpreter::MemoryInstance {
+		&*self.memory
+	}
+
+	fn mem_copy(&self, context: interpreter::CallerContext) 
+		-> Result<Option<interpreter::RuntimeValue>, interpreter::Error> 
+	{
+		let len = context.value_stack.pop_as::<i32>()? as u32;
+		let dst = context.value_stack.pop_as::<i32>()? as u32;
+		let src = context.value_stack.pop_as::<i32>()? as u32;
+
+		let mem = self.memory().get(src, len as usize)?;
+		self.memory().set(dst, &mem)?;
+
+		Ok(Some(0i32.into()))
+	}
+}
+
+impl<'a> interpreter::UserFunctionExecutor for Runtime<'a> {
+	fn execute(&mut self, name: &str, context: interpreter::CallerContext) 
+		-> Result<Option<interpreter::RuntimeValue>, interpreter::Error>
+	{
+		match name {
+			"_malloc" => {
+				self.malloc(context)
+			},
+			"_free" => {
+				// Since it is arena allocator, free does nothing
+				// todo: update if changed
+				self.user_noop(context)
+			},
+			"_storage_read" => {
+				self.storage_read(context)
+			},
+			"_storage_write" => {
+				self.storage_write(context)
+			},
+			"_suicide" => {
+				self.suicide(context)
+			},
+			"_create" => {
+				self.create(context)
+			},
+			"_debug" => {
+				self.debug_log(context)
+			},
+			"gas" => {
+				self.gas(context)
+			},
+			"_emscripten_memcpy_big" => {
+				self.mem_copy(context)
+			},
+			_ => {
+				trace!("Unknown env func: '{}'", name);
+				self.user_trap(context)
+			}
+		}
+	}
+}

ethcore/src/evm/wasm/tests.rs

@@ -0,0 +1,279 @@
+use std::path::PathBuf;
+use std::fs::File;
+use std::io::Read;
+use std::sync::Arc;
+
+use ethcore_logger::init_log;
+use super::super::tests::{FakeExt, FakeCall, FakeCallType};
+use super::WasmInterpreter;
+use evm::{self, Evm, GasLeft};
+use action_params::{ActionParams, ActionValue};
+use util::{U256, H256, Address};
+
+fn load_sample(name: &str) -> Vec<u8> {
+	let mut path = PathBuf::from("./res/wasm-tests/compiled");
+	path.push(name);
+	let mut file = File::open(path).expect(&format!("File {} for test to exist", name));
+	let mut data = vec![];
+	file.read_to_end(&mut data).expect(&format!("Test {} to load ok", name));
+	data
+}
+
+fn test_finalize(res: Result<GasLeft, evm::Error>) -> Result<U256, evm::Error> {
+	match res {
+		Ok(GasLeft::Known(gas)) => Ok(gas),
+		Ok(GasLeft::NeedsReturn{..}) => unimplemented!(), // since ret is unimplemented.
+		Err(e) => Err(e),
+	}
+}
+
+fn wasm_interpreter() -> WasmInterpreter {
+	WasmInterpreter::new().expect("wasm interpreter to create without errors")
+}
+
+/// Empty contract does almost nothing except producing 1 (one) local node debug log message
+#[test]
+fn empty() {
+	init_log();
+
+	let code = load_sample("empty.wasm");
+	let address: Address = "0f572e5295c57f15886f9b263e2f6d2d6c7b5ec6".parse().unwrap();
+
+	let mut params = ActionParams::default();
+	params.address = address.clone();
+	params.gas = U256::from(100_000);
+	params.code = Some(Arc::new(code));
+	let mut ext = FakeExt::new();
+
+	let gas_left = {
+		let mut interpreter = wasm_interpreter();
+		test_finalize(interpreter.exec(params, &mut ext)).unwrap()
+	};
+
+	assert_eq!(gas_left, U256::from(99_996));
+}
+
+// This test checks if the contract deserializes payload header properly.
+//   Contract is provided with receiver(address), sender, origin and transaction value
+//   logger.wasm writes all these provided fixed header fields to some arbitrary storage keys.
+#[test]
+fn logger() {
+	init_log();
+
+	let code = load_sample("logger.wasm");
+	let address: Address = "0f572e5295c57f15886f9b263e2f6d2d6c7b5ec6".parse().unwrap();
+	let sender: Address = "0d0d0d0d0d0d0d0d0d0d0d0d0d0d0d0d0d0d0d0d".parse().unwrap();
+	let origin: Address = "0102030405060708090a0b0c0d0e0f1011121314".parse().unwrap();
+
+	let mut params = ActionParams::default();
+	params.address = address.clone();
+	params.sender = sender.clone();
+	params.origin = origin.clone();
+	params.gas = U256::from(100_000);
+	params.value = ActionValue::transfer(1_000_000_000);
+	params.code = Some(Arc::new(code));
+	let mut ext = FakeExt::new();
+
+	let gas_left = {
+		let mut interpreter = wasm_interpreter();
+		test_finalize(interpreter.exec(params, &mut ext)).unwrap()
+	};
+
+	println!("ext.store: {:?}", ext.store);
+	assert_eq!(gas_left, U256::from(99581));
+	let address_val: H256 = address.into();
+	assert_eq!(
+		ext.store.get(&"0100000000000000000000000000000000000000000000000000000000000000".parse().unwrap()).expect("storage key to exist"),
+		&address_val,
+		"Logger sets 0x01 key to the provided address"
+	);
+	let sender_val: H256 = sender.into();
+	assert_eq!(
+		ext.store.get(&"0200000000000000000000000000000000000000000000000000000000000000".parse().unwrap()).expect("storage key to exist"),
+		&sender_val,
+		"Logger sets 0x02 key to the provided sender"
+	);
+	let origin_val: H256 = origin.into();
+	assert_eq!(
+		ext.store.get(&"0300000000000000000000000000000000000000000000000000000000000000".parse().unwrap()).expect("storage key to exist"),
+		&origin_val,
+		"Logger sets 0x03 key to the provided origin"
+	);
+	assert_eq!(
+		U256::from(ext.store.get(&"0400000000000000000000000000000000000000000000000000000000000000".parse().unwrap()).expect("storage key to exist")),
+		U256::from(1_000_000_000),
+		"Logger sets 0x04 key to the trasferred value"
+	);
+}
+
+// This test checks if the contract can allocate memory and pass pointer to the result stream properly.
+//   1. Contract is being provided with the call descriptor ptr
+//   2. Descriptor ptr is 16 byte length
+//   3. The last 8 bytes of call descriptor is the space for the contract to fill [result_ptr[4], result_len[4]]
+//      if it has any result.
+#[test]
+fn identity() {
+	init_log();
+
+	let code = load_sample("identity.wasm");
+	let sender: Address = "01030507090b0d0f11131517191b1d1f21232527".parse().unwrap();
+
+	let mut params = ActionParams::default();
+	params.sender = sender.clone();
+	params.gas = U256::from(100_000);
+	params.code = Some(Arc::new(code));
+	let mut ext = FakeExt::new();
+
+	let (gas_left, result) = {
+		let mut interpreter = wasm_interpreter();
+		let result = interpreter.exec(params, &mut ext).expect("Interpreter to execute without any errors");
+		match result {
+			GasLeft::Known(_) => { panic!("Identity contract should return payload"); },
+			GasLeft::NeedsReturn { gas_left: gas, data: result, apply_state: _apply } => (gas, result.to_vec()),
+		}
+	};
+
+	assert_eq!(gas_left, U256::from(99_689));
+
+	assert_eq!(
+		Address::from_slice(&result),
+		sender,
+		"Idenity test contract does not return the sender passed"
+	);
+}
+
+// Dispersion test sends byte array and expect the contract to 'disperse' the original elements with
+// their modulo 19 dopant. 
+// The result is always twice as long as the input.
+// This also tests byte-perfect memory allocation and in/out ptr lifecycle. 
+#[test]
+fn dispersion() {
+	init_log();
+
+	let code = load_sample("dispersion.wasm");
+
+	let mut params = ActionParams::default();
+	params.gas = U256::from(100_000);
+	params.code = Some(Arc::new(code));
+	params.data = Some(vec![
+		0u8, 125, 197, 255, 19
+	]);
+	let mut ext = FakeExt::new();
+
+	let (gas_left, result) = {
+		let mut interpreter = wasm_interpreter();
+		let result = interpreter.exec(params, &mut ext).expect("Interpreter to execute without any errors");
+		match result {
+			GasLeft::Known(_) => { panic!("Dispersion routine should return payload"); },
+			GasLeft::NeedsReturn { gas_left: gas, data: result, apply_state: _apply } => (gas, result.to_vec()),
+		}
+	};
+
+	assert_eq!(gas_left, U256::from(99_402));
+
+	assert_eq!(
+		result,
+		vec![0u8, 0, 125, 11, 197, 7, 255, 8, 19, 0]
+	);
+}
+
+#[test]
+fn suicide_not() {
+	init_log();
+
+	let code = load_sample("suicidal.wasm");
+
+	let mut params = ActionParams::default();
+	params.gas = U256::from(100_000);
+	params.code = Some(Arc::new(code));
+	params.data = Some(vec![
+		0u8
+	]);
+	let mut ext = FakeExt::new();
+
+	let (gas_left, result) = {
+		let mut interpreter = wasm_interpreter();
+		let result = interpreter.exec(params, &mut ext).expect("Interpreter to execute without any errors");
+		match result {
+			GasLeft::Known(_) => { panic!("Suicidal contract should return payload when had not actualy killed himself"); },
+			GasLeft::NeedsReturn { gas_left: gas, data: result, apply_state: _apply } => (gas, result.to_vec()),
+		}
+	};
+
+	assert_eq!(gas_left, U256::from(99_703));
+
+	assert_eq!(
+		result,
+		vec![0u8]
+	);	
+}
+
+#[test]
+fn suicide() {
+	init_log();
+
+	let code = load_sample("suicidal.wasm");
+
+	let refund: Address = "01030507090b0d0f11131517191b1d1f21232527".parse().unwrap();
+	let mut params = ActionParams::default();
+	params.gas = U256::from(100_000);
+	params.code = Some(Arc::new(code));
+
+	let mut args = vec![127u8];
+	args.extend(refund.to_vec());
+	params.data = Some(args);
+
+	let mut ext = FakeExt::new();
+
+	let gas_left = {
+		let mut interpreter = wasm_interpreter();
+		let result = interpreter.exec(params, &mut ext).expect("Interpreter to execute without any errors");
+		match result {
+			GasLeft::Known(gas) => gas,
+			GasLeft::NeedsReturn { .. } => {
+				panic!("Suicidal contract should not return anything when had killed itself");
+			},
+		}
+	};
+
+	assert_eq!(gas_left, U256::from(99_747));
+	assert!(ext.suicides.contains(&refund));
+}
+
+#[test]
+fn create() {
+	init_log();
+
+	let mut params = ActionParams::default();
+	params.gas = U256::from(100_000);
+	params.code = Some(Arc::new(load_sample("creator.wasm")));
+	params.data = Some(vec![0u8, 2, 4, 8, 16, 32, 64, 128]);
+	params.value = ActionValue::transfer(1_000_000_000);
+
+	let mut ext = FakeExt::new();
+
+	let gas_left = {
+		let mut interpreter = wasm_interpreter();
+		let result = interpreter.exec(params, &mut ext).expect("Interpreter to execute without any errors");
+		match result {
+			GasLeft::Known(gas) => gas,
+			GasLeft::NeedsReturn { .. } => {
+				panic!("Create contract should not return anthing because ext always fails on creation");
+			},
+		}
+	};
+
+	trace!(target: "wasm", "fake_calls: {:?}", &ext.calls);
+	assert!(ext.calls.contains(
+		&FakeCall {
+			call_type: FakeCallType::Create,
+			gas: U256::from(99_778),
+			sender_address: None,
+			receive_address: None,
+			value: Some(1_000_000_000.into()),
+			data: vec![0u8, 2, 4, 8, 16, 32, 64, 128],
+			code_address: None,
+		}
+	));
+	assert_eq!(gas_left, U256::from(99_768));
+}

ethcore/src/executive.rs

@@ -22,7 +22,7 @@ use engines::Engine;
 use types::executed::CallType;
 use env_info::EnvInfo;
 use error::ExecutionError;
-use evm::{self, Ext, Finalize, CreateContractAddress, FinalizationResult, ReturnData, CleanDustMode};
+use evm::{self, wasm, Factory, Ext, Finalize, CreateContractAddress, FinalizationResult, ReturnData, CleanDustMode};
 use externalities::*;
 use trace::{FlatTrace, Tracer, NoopTracer, ExecutiveTracer, VMTrace, VMTracer, ExecutiveVMTracer, NoopVMTracer};
 use transaction::{Action, SignedTransaction};
@@ -34,6 +34,8 @@ pub use types::executed::{Executed, ExecutionResult};
 /// Maybe something like here: `https://github.com/ethereum/libethereum/blob/4db169b8504f2b87f7d5a481819cfb959fc65f6c/libethereum/ExtVM.cpp`
 const STACK_SIZE_PER_DEPTH: usize = 24*1024;
 
+const WASM_MAGIC_NUMBER: &'static [u8; 4] = b"\0asm";
+
 /// Returns new address created from address, nonce, and code hash
 pub fn contract_address(address_scheme: CreateContractAddress, sender: &Address, nonce: &U256, code: &[u8]) -> (Address, Option<H256>) {
 	use rlp::RlpStream;
@@ -72,6 +74,20 @@ pub struct TransactOptions {
 	pub check_nonce: bool,
 }
 
+pub fn executor<E>(engine: &E, vm_factory: &Factory, params: &ActionParams) 
+	-> Box<evm::Evm> where E: Engine + ?Sized
+{
+	if engine.supports_wasm() && params.code.as_ref().map_or(false, |code| code.len() > 4 && &code[0..4] == WASM_MAGIC_NUMBER) {
+		Box::new(
+			wasm::WasmInterpreter::new()
+				// prefer to fail fast
+				.expect("Failed to create wasm runtime")
+		)
+	} else {
+		vm_factory.create(params.gas)
+	}
+}
+
 /// Transaction executor.
 pub struct Executive<'a, B: 'a + StateBackend, E: 'a + Engine + ?Sized> {
 	state: &'a mut State<B>,
@@ -263,18 +279,19 @@ impl<'a, B: 'a + StateBackend, E: Engine + ?Sized> Executive<'a, B, E> {
 			let vm_factory = self.state.vm_factory();
 			let mut ext = self.as_externalities(OriginInfo::from(&params), unconfirmed_substate, output_policy, tracer, vm_tracer, static_call);
 			trace!(target: "executive", "ext.schedule.have_delegate_call: {}", ext.schedule().have_delegate_call);
-			return vm_factory.create(params.gas).exec(params, &mut ext).finalize(ext);
+			return executor(self.engine, &vm_factory, &params).exec(params, &mut ext).finalize(ext);
 		}
 
 		// Start in new thread to reset stack
 		// TODO [todr] No thread builder yet, so we need to reset once for a while
 		// https://github.com/aturon/crossbeam/issues/16
 		crossbeam::scope(|scope| {
+			let engine = self.engine;
 			let vm_factory = self.state.vm_factory();
 			let mut ext = self.as_externalities(OriginInfo::from(&params), unconfirmed_substate, output_policy, tracer, vm_tracer, static_call);
 
 			scope.spawn(move || {
-				vm_factory.create(params.gas).exec(params, &mut ext).finalize(ext)
+				executor(engine, &vm_factory, &params).exec(params, &mut ext).finalize(ext)
 			})
 		}).join()
 	}
@@ -562,6 +579,7 @@ impl<'a, B: 'a + StateBackend, E: Engine + ?Sized> Executive<'a, B, E> {
 				| Err(evm::Error::BadInstruction {.. })
 				| Err(evm::Error::StackUnderflow {..})
 				| Err(evm::Error::BuiltIn {..})
+				| Err(evm::Error::Wasm {..})
 				| Err(evm::Error::OutOfStack {..})
 				| Err(evm::Error::MutableCallInStaticContext)
 				| Ok(FinalizationResult { apply_state: false, .. }) => {

ethcore/src/lib.rs

@@ -105,6 +105,8 @@ extern crate semver;
 extern crate stats;
 extern crate time;
 extern crate transient_hashmap;
+extern crate parity_wasm;
+extern crate wasm_utils;
 
 #[macro_use]
 extern crate log;

ethcore/src/spec/spec.rs

@@ -83,6 +83,8 @@ pub struct CommonParams {
 	pub nonce_cap_increment: u64,
 	/// Enable dust cleanup for contracts.
 	pub remove_dust_contracts: bool,
+	/// Wasm support
+	pub wasm: bool,
 }
 
 impl From<ethjson::spec::Params> for CommonParams {
@@ -110,6 +112,7 @@ impl From<ethjson::spec::Params> for CommonParams {
 			dust_protection_transition: p.dust_protection_transition.map_or(BlockNumber::max_value(), Into::into),
 			nonce_cap_increment: p.nonce_cap_increment.map_or(64, Into::into),
 			remove_dust_contracts: p.remove_dust_contracts.unwrap_or(false),
+			wasm: p.wasm.unwrap_or(false),
 		}
 	}
 }

ethcore/src/types/trace_types/error.rs

@@ -42,6 +42,8 @@ pub enum Error {
 	Internal,
 	/// When execution tries to modify the state in static context
 	MutableCallInStaticContext,
+	/// Wasm error
+	Wasm,
 }
 
 impl<'a> From<&'a EvmError> for Error {
@@ -53,6 +55,7 @@ impl<'a> From<&'a EvmError> for Error {
 			EvmError::StackUnderflow { .. } => Error::StackUnderflow,
 			EvmError::OutOfStack { .. } => Error::OutOfStack,
 			EvmError::BuiltIn { .. } => Error::BuiltIn,
+			EvmError::Wasm { .. } => Error::Wasm,
 			EvmError::Internal(_) => Error::Internal,
 			EvmError::MutableCallInStaticContext => Error::MutableCallInStaticContext,
 		}
@@ -75,6 +78,7 @@ impl fmt::Display for Error {
 			StackUnderflow => "Stack underflow",
 			OutOfStack => "Out of stack",
 			BuiltIn => "Built-in failed",
+			Wasm => "Wasm runtime error",
 			Internal => "Internal error",
 			MutableCallInStaticContext => "Mutable Call In Static Context",
 		};
@@ -94,6 +98,7 @@ impl Encodable for Error {
 			Internal => 5,
 			BuiltIn => 6,
 			MutableCallInStaticContext => 7,
+			Wasm => 8,
 		};
 
 		s.append_internal(&value);
@@ -113,6 +118,7 @@ impl Decodable for Error {
 			5 => Ok(Internal),
 			6 => Ok(BuiltIn),
 			7 => Ok(MutableCallInStaticContext),
+			8 => Ok(Wasm),
 			_ => Err(DecoderError::Custom("Invalid error type")),
 		}
 	}

json/src/spec/params.rs

@@ -89,6 +89,8 @@ pub struct Params {
 	pub nonce_cap_increment: Option<Uint>,
 	/// See `CommonParams` docs.
 	pub remove_dust_contracts : Option<bool>,
+	/// Wasm support flag
+	pub wasm: Option<bool>,
 }
 
 #[cfg(test)]