Bump version to 0.6.1

Introduce substrate contracts support.

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "pwasm-utils"
-version = "0.1.5"
+version = "0.6.1"
 authors = ["Nikolay Volf <nikvolf@gmail.com>", "Sergey Pepyakin <s.pepyakin@gmail.com>"]
 license = "MIT/Apache-2.0"
 readme = "README.md"
@@ -8,7 +8,7 @@ description = "Collection of command-line utilities and corresponding Rust api f
 keywords = ["wasm", "webassembly", "pwasm"]
 
 [dependencies]
-parity-wasm = { version = "0.30", default-features = false }
+parity-wasm = { version = "0.31", default-features = false }
 log = { version = "0.4", default-features = false }
 byteorder = { version = "1", default-features = false }
 

README.md

@@ -2,31 +2,31 @@
 
 [![Build Status](https://travis-ci.org/paritytech/wasm-utils.svg?branch=master)](https://travis-ci.org/paritytech/wasm-utils)
 
-Collection of WASM utilities used in Parity and WASM contract devepment
+Collection of WASM utilities used in Parity and WASM contract development
 
 ## Build tools for cargo
 
 Easiest way to use is to install via `cargo install`:
 
 ```
-cargo install pwasm-utils --bin wasm-build
+cargo install pwasm-utils-cli --bin wasm-build
 ```
 
 ## Symbols pruning (wasm-prune)
 
 ```
-cargo install pwasm-utils
+cargo install pwasm-utils-cli --bin wasm-prune
 wasm-prune <input_wasm_binary.wasm> <output_wasm_binary.wasm>
 ```
 
-This will optimize WASM symbols tree to leave only those elements that are used by contract `_call` function entry.
+This will optimize WASM symbols tree to leave only those elements that are used by contract `call` function entry.
 
 ## Gas counter (wasm-gas)
 
 For development puposes, raw WASM contract can be injected with gas counters (the same way as it done by Parity runtime when running contracts)
 
 ```
-cargo install pwasm-utils
+cargo install pwasm-utils-cli --bin wasm-gas
 wasm-gas <input_wasm_binary.wasm> <output_wasm_binary.wasm>
 ```
 
@@ -42,7 +42,7 @@ Parity WASM runtime provides some library functions that can be commonly found i
 And then substitutes them with invocations of the imported ones. Should be run before `wasm-opt` for better results.
 
 ```
-cargo install pwasm-utils
+cargo install pwasm-utils-cli --bin wasm-ext
 wasm-ext <input_wasm_binary.wasm> <output_wasm_binary.wasm>
 ```
 
@@ -56,3 +56,9 @@ All executables use corresponding api methods of the root crate and can be combi
 license and the Apache License (Version 2.0), at your choice.
 
 See LICENSE-APACHE, and LICENSE-MIT for details.
+
+## Contribution
+
+Unless you explicitly state otherwise, any contribution intentionally submitted
+for inclusion in `wasm-utils` by you, as defined in the Apache-2.0 license, shall be
+dual licensed as above, without any additional terms or conditions.

cli/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "pwasm-utils-cli"
-version = "0.1.5"
+version = "0.6.0"
 authors = ["Nikolay Volf <nikvolf@gmail.com>", "Sergey Pepyakin <s.pepyakin@gmail.com>"]
 license = "MIT/Apache-2.0"
 readme = "README.md"
@@ -29,9 +29,17 @@ path = "build/main.rs"
 name = "wasm-stack-height"
 path = "stack_height/main.rs"
 
+[[bin]]
+name = "wasm-pack"
+path = "pack/main.rs"
+
+[[bin]]
+name = "wasm-check"
+path = "check/main.rs"
+
 [dependencies]
-parity-wasm = "0.30"
-pwasm-utils = { path = ".." }
+parity-wasm = "0.31"
+pwasm-utils = { path = "..", version = "0.6" }
 glob = "0.2"
 clap = "2.24"
 log = "0.4"

cli/README.md

@@ -0,0 +1,11 @@
+# pwasm-utils-cli
+
+Collection of WASM utilities used in Parity and WASM contract devepment
+
+## Install
+
+Easiest way to use is to install via `cargo install`:
+
+```
+cargo install pwasm-utils-cli
+```

cli/build/main.rs

@@ -9,13 +9,11 @@ extern crate pwasm_utils_cli as logger;
 mod source;
 
 use std::{fs, io};
-use std::io::Write;
 use std::path::PathBuf;
 
 use clap::{App, Arg};
 use parity_wasm::elements;
-
-use utils::{CREATE_SYMBOL, CALL_SYMBOL, ununderscore_funcs, externalize_mem, shrink_unknown_stack};
+use utils::{build, BuildError, SourceTarget, TargetRuntime};
 
 #[derive(Debug)]
 pub enum Error {
@@ -23,38 +21,18 @@ pub enum Error {
 	FailedToCopy(String),
 	Decoding(elements::Error, String),
 	Encoding(elements::Error),
-	Packing(utils::PackingError),
-	Optimizer,
-}
-
-impl From<io::Error> for Error {
-	fn from(err: io::Error) -> Self {
-		Error::Io(err)
-	}
-}
-
-impl From<utils::OptimizerError> for Error {
-	fn from(_err: utils::OptimizerError) -> Self {
-		Error::Optimizer
-	}
-}
-
-impl From<utils::PackingError> for Error {
-	fn from(err: utils::PackingError) -> Self {
-		Error::Packing(err)
-	}
+	Build(BuildError),
 }
 
 impl std::fmt::Display for Error {
 	fn fmt(&self, f: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
-		use Error::*;
+		use self::Error::*;
 		match *self {
 			Io(ref io) => write!(f, "Generic i/o error: {}", io),
 			FailedToCopy(ref msg) => write!(f, "{}. Have you tried to run \"cargo build\"?", msg),
 			Decoding(ref err, ref file) => write!(f, "Decoding error ({}). Must be a valid wasm file {}. Pointed wrong file?", err, file),
 			Encoding(ref err) => write!(f, "Encoding error ({}). Almost impossible to happen, no free disk space?", err),
-			Optimizer => write!(f, "Optimization error due to missing export section. Pointed wrong file?"),
-			Packing(ref e) => write!(f, "Packing failed due to module structure error: {}. Sure used correct libraries for building contracts?", e),
+			Build(ref err) => write!(f, "Build error: {}", err)
 		}
 	}
 }
@@ -70,8 +48,8 @@ pub fn process_output(input: &source::SourceInput) -> Result<(), Error> {
 	let wasm_name = input.bin_name().to_string().replace("-", "_");
 	cargo_path.push(
 		match input.target() {
-			source::SourceTarget::Emscripten => source::EMSCRIPTEN_TRIPLET,
-			source::SourceTarget::Unknown => source::UNKNOWN_TRIPLET,
+			SourceTarget::Emscripten => source::EMSCRIPTEN_TRIPLET,
+			SourceTarget::Unknown => source::UNKNOWN_TRIPLET,
 		}
 	);
 	cargo_path.push("release");
@@ -87,14 +65,6 @@ pub fn process_output(input: &source::SourceInput) -> Result<(), Error> {
 	Ok(())
 }
 
-fn has_ctor(module: &elements::Module) -> bool {
-	if let Some(ref section) = module.export_section() {
-		section.entries().iter().any(|e| CREATE_SYMBOL == e.field())
-	} else {
-		false
-	}
-}
-
 fn do_main() -> Result<(), Error> {
 	logger::init_log();
 
@@ -107,6 +77,12 @@ fn do_main() -> Result<(), Error> {
 			.index(2)
 			.required(true)
 			.help("Wasm binary name"))
+		.arg(Arg::with_name("target-runtime")
+			.help("What runtime we are compiling to")
+			.long("target-runtime")
+			.takes_value(true)
+			.default_value("pwasm")
+			.possible_values(&["substrate", "pwasm"]))
 		.arg(Arg::with_name("skip_optimization")
 			.help("Skip symbol optimization step producing final wasm")
 			.long("skip-optimization"))
@@ -137,6 +113,11 @@ fn do_main() -> Result<(), Error> {
 			.help("Shrinks the new stack size for wasm32-unknown-unknown")
 			.takes_value(true)
 			.long("shrink-stack"))
+		.arg(Arg::with_name("public_api")
+			.help("Preserves specific imports in the library")
+			.takes_value(true)
+			.long("public-api"))
+
 		.get_matches();
 
     let target_dir = matches.value_of("target").expect("is required; qed");
@@ -161,65 +142,57 @@ fn do_main() -> Result<(), Error> {
 
 	let path = wasm_path(&source_input);
 
-	let mut module = parity_wasm::deserialize_file(&path)
+	let module = parity_wasm::deserialize_file(&path)
 		.map_err(|e| Error::Decoding(e, path.to_string()))?;
 
-	if let source::SourceTarget::Emscripten = source_input.target() {
-		module = ununderscore_funcs(module);
-	}
-
-	if let source::SourceTarget::Unknown = source_input.target() {
-		// 49152 is 48kb!
-		if matches.is_present("enforce_stack_adjustment") {
-			let stack_size: u32 = matches.value_of("shrink_stack").unwrap_or_else(|| "49152").parse().expect("New stack size is not valid u32");
-			assert!(stack_size <= 1024*1024);
-			let (new_module, new_stack_top) = shrink_unknown_stack(module, 1024 * 1024 - stack_size);
-			module = new_module;
-			let mut stack_top_page = new_stack_top / 65536;
-			if new_stack_top % 65536 > 0 { stack_top_page += 1 };
-			module = externalize_mem(module, Some(stack_top_page), 16);
-		} else {
-			module = externalize_mem(module, None, 16);
-		}
-	}
-
-	if let Some(runtime_type) = matches.value_of("runtime_type") {
-		let runtime_type: &[u8] = runtime_type.as_bytes();
-		if runtime_type.len() != 4 {
+	let runtime_type_version = if let (Some(runtime_type), Some(runtime_version))
+		 = (matches.value_of("runtime_type"), matches.value_of("runtime_version")) {
+		let mut ty: [u8; 4] = Default::default();
+		let runtime_bytes = runtime_type.as_bytes();
+		if runtime_bytes.len() != 4 {
 			panic!("--runtime-type should be equal to 4 bytes");
 		}
-		let runtime_version: u32 = matches.value_of("runtime_version").unwrap_or("1").parse()
+		ty.copy_from_slice(runtime_bytes);
+		let version: u32 = runtime_version.parse()
 			.expect("--runtime-version should be a positive integer");
-		module = utils::inject_runtime_type(module, &runtime_type, runtime_version);
-	}
+		Some((ty, version))
+	} else {
+		None
+	};
 
-	let mut ctor_module = module.clone();
+	let public_api_entries = matches.value_of("public_api")
+		.map(|val| val.split(",").collect())
+		.unwrap_or(Vec::new());
 
-	if !matches.is_present("skip_optimization") {
-		utils::optimize(
-			&mut module,
-			vec![CALL_SYMBOL]
-		)?;
-	}
+	let target_runtime = match matches.value_of("target-runtime").expect("target-runtime has a default value; qed") {
+		"pwasm" => TargetRuntime::pwasm(),
+		"substrate" => TargetRuntime::substrate(),
+		_ => unreachable!("all possible values are enumerated in clap config; qed"),
+	};
+
+	let (module, ctor_module) = build(
+		module,
+		source_input.target(),
+		runtime_type_version,
+		&public_api_entries,
+		matches.is_present("enforce_stack_adjustment"),
+		matches.value_of("shrink_stack").unwrap_or_else(|| "49152").parse()
+			.expect("New stack size is not valid u32"),
+		matches.is_present("skip_optimization"),
+		&target_runtime,
+	).map_err(Error::Build)?;
 
 	if let Some(save_raw_path) = matches.value_of("save_raw") {
 		parity_wasm::serialize_to_file(save_raw_path, module.clone()).map_err(Error::Encoding)?;
 	}
 
-	let raw_module = parity_wasm::serialize(module).map_err(Error::Encoding)?;
-
-	// If module has an exported function with name=CREATE_SYMBOL
-	// build will pack the module (raw_module) into this funciton and export as CALL_SYMBOL.
-	// Otherwise it will just save an optimised raw_module
-	if has_ctor(&ctor_module) {
-		if !matches.is_present("skip_optimization") {
-			utils::optimize(&mut ctor_module, vec![CREATE_SYMBOL])?;
-		}
-		let ctor_module = utils::pack_instance(raw_module, ctor_module)?;
-		parity_wasm::serialize_to_file(&path, ctor_module).map_err(Error::Encoding)?;
+	if let Some(ctor_module) = ctor_module {
+		parity_wasm::serialize_to_file(
+			&path,
+			ctor_module,
+		).map_err(Error::Encoding)?;
 	} else {
-		let mut file = fs::File::create(&path)?;
-		file.write_all(&raw_module)?;
+		parity_wasm::serialize_to_file(&path, module).map_err(Error::Encoding)?;
 	}
 
 	Ok(())

cli/build/source.rs

@@ -3,12 +3,7 @@
 pub const UNKNOWN_TRIPLET: &str = "wasm32-unknown-unknown";
 pub const EMSCRIPTEN_TRIPLET: &str = "wasm32-unknown-emscripten";
 
-/// Target configiration of previous build step
-#[derive(Debug, Clone, Copy)]
-pub enum SourceTarget {
-	Emscripten,
-	Unknown,
-}
+use utils::SourceTarget;
 
 /// Configuration of previous build step (cargo compilation)
 #[derive(Debug)]
@@ -59,4 +54,4 @@ impl<'a> SourceInput<'a> {
 	pub fn target(&self) -> SourceTarget {
 		self.target
 	}
-}
+}

cli/check/main.rs

@@ -0,0 +1,102 @@
+extern crate parity_wasm;
+extern crate pwasm_utils as utils;
+extern crate pwasm_utils_cli as logger;
+extern crate clap;
+
+use clap::{App, Arg};
+use parity_wasm::elements;
+
+fn fail(msg: &str) -> ! {
+    eprintln!("{}", msg);
+    std::process::exit(1)
+}
+
+const ALLOWED_IMPORTS: &'static [&'static str] = &[
+    "ret",
+    "storage_read",
+    "storage_write",
+    "balance",
+    "sender",
+    "origin",
+    "fetch_input",
+    "input_length",
+    "ccall",
+    "dcall",
+    "scall",
+    "create",
+    "balance",
+    "blockhash",
+    "blocknumber",
+    "coinbase",
+    "timestamp",
+    "difficulty",
+    "gaslimit",
+    "address",
+    "value",
+    "suicide",
+    "panic",
+    "elog",
+    "abort"
+];
+
+fn main() {
+    logger::init_log();
+
+    let matches = App::new("wasm-check")
+                        .arg(Arg::with_name("input")
+                            .index(1)
+                            .required(true)
+                            .help("Input WASM file"))
+                        .get_matches();
+
+    let input = matches.value_of("input").expect("is required; qed");
+
+    let module = parity_wasm::deserialize_file(&input).expect("Input module deserialization failed");
+
+    for section in module.sections() {
+        match *section {
+            elements::Section::Import(ref import_section) => {
+                let mut has_imported_memory_properly_named = false;
+                for entry in import_section.entries() {
+                    if entry.module() != "env" {
+                        fail("All imports should be from env");
+                    }
+                    match *entry.external() {
+                        elements::External::Function(_) => {
+                            if !ALLOWED_IMPORTS.contains(&entry.field()) {
+                                fail(&format!("'{}' is not supported by the runtime", entry.field()));
+                            }
+                        },
+                        elements::External::Memory(m) => {
+                            if entry.field() == "memory" {
+                                has_imported_memory_properly_named = true;
+                            }
+
+                            let max = if let Some(max) = m.limits().maximum() {
+                                max
+                            } else {
+                                fail("There is a limit on memory in Parity runtime, and this program does not limit memory");
+                            };
+
+                            if max > 16 {
+                                fail(&format!(
+                                    "Parity runtime has 1Mb limit (16 pages) on max contract memory, this program speicifies {}",
+                                    max
+                                ));
+                            }
+                        },
+                        elements::External::Global(_) => {
+                            fail("Parity runtime does not provide any globals")
+                        },
+                        _ => { continue; }
+                    }
+                }
+
+                if !has_imported_memory_properly_named {
+                    fail("No imported memory from env::memory in the contract");
+                }
+            }
+            _ => { continue; }
+        }
+    }
+}

cli/pack/main.rs

@@ -0,0 +1,37 @@
+extern crate parity_wasm;
+extern crate pwasm_utils as utils;
+extern crate pwasm_utils_cli as logger;
+extern crate clap;
+
+use clap::{App, Arg};
+
+fn main() {
+    logger::init_log();
+
+	let target_runtime = utils::TargetRuntime::pwasm();
+
+    let matches = App::new("wasm-pack")
+                        .arg(Arg::with_name("input")
+                            .index(1)
+                            .required(true)
+                            .help("Input WASM file"))
+                        .arg(Arg::with_name("output")
+                            .index(2)
+                            .required(true)
+                            .help("Output WASM file"))
+                        .get_matches();
+
+    let input = matches.value_of("input").expect("is required; qed");
+    let output = matches.value_of("output").expect("is required; qed");
+
+    let module = parity_wasm::deserialize_file(&input).expect("Input module deserialization failed");
+    let ctor_module = module.clone();
+	let raw_module = parity_wasm::serialize(module).expect("Serialization failed");
+
+    // Invoke packer
+    let mut result_module = utils::pack_instance(raw_module, ctor_module, &utils::TargetRuntime::pwasm()).expect("Packing failed");
+    // Optimize constructor, since it does not need everything
+    utils::optimize(&mut result_module, vec![target_runtime.call_symbol]).expect("Optimization failed");
+
+    parity_wasm::serialize_to_file(&output, result_module).expect("Serialization failed");
+}

cli/prune/main.rs

@@ -8,7 +8,9 @@ use clap::{App, Arg};
 fn main() {
     logger::init_log();
 
-    let matches = App::new("wasm-opt")
+	let target_runtime = utils::TargetRuntime::pwasm();
+
+    let matches = App::new("wasm-prune")
                         .arg(Arg::with_name("input")
                             .index(1)
                             .required(true)
@@ -22,12 +24,12 @@ fn main() {
                             .short("e")
                             .takes_value(true)
                             .value_name("functions")
-                            .help("Comma-separated list of exported functions to keep. Default: _call"))
+                            .help(&format!("Comma-separated list of exported functions to keep. Default: '{}'", target_runtime.call_symbol)))
                         .get_matches();
 
     let exports = matches
                     .value_of("exports")
-                    .unwrap_or("_call")
+                    .unwrap_or(target_runtime.call_symbol)
                     .split(',')
                     .collect();
 
@@ -39,7 +41,7 @@ fn main() {
     // Invoke optimizer
     //   Contract is supposed to have only these functions as public api
     //   All other symbols not usable by this list is optimized away
-    utils::optimize(&mut module, exports).expect("Optimizer to finish without errors");
+    utils::optimize(&mut module, exports).expect("Optimizer failed");
 
-    parity_wasm::serialize_to_file(&output, module).unwrap();
+    parity_wasm::serialize_to_file(&output, module).expect("Serialization failed");
 }

src/build.rs

@@ -0,0 +1,118 @@
+use std;
+use super::{
+	optimize,
+	pack_instance,
+	ununderscore_funcs,
+	externalize_mem,
+	shrink_unknown_stack,
+	inject_runtime_type,
+	PackingError,
+	OptimizerError,
+	TargetRuntime,
+};
+use parity_wasm;
+use parity_wasm::elements;
+
+#[derive(Debug)]
+pub enum Error {
+	Encoding(elements::Error),
+	Packing(PackingError),
+	Optimizer,
+}
+
+impl From<OptimizerError> for Error {
+	fn from(_err: OptimizerError) -> Self {
+		Error::Optimizer
+	}
+}
+
+impl From<PackingError> for Error {
+	fn from(err: PackingError) -> Self {
+		Error::Packing(err)
+	}
+}
+
+#[derive(Debug, Clone, Copy)]
+pub enum SourceTarget {
+	Emscripten,
+	Unknown,
+}
+
+impl std::fmt::Display for Error {
+	fn fmt(&self, f: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
+		use self::Error::*;
+		match *self {
+			Encoding(ref err) => write!(f, "Encoding error ({})", err),
+			Optimizer => write!(f, "Optimization error due to missing export section. Pointed wrong file?"),
+			Packing(ref e) => write!(f, "Packing failed due to module structure error: {}. Sure used correct libraries for building contracts?", e),
+		}
+	}
+}
+
+fn has_ctor(module: &elements::Module, target_runtime: &TargetRuntime) -> bool {
+	if let Some(ref section) = module.export_section() {
+		section.entries().iter().any(|e| target_runtime.create_symbol == e.field())
+	} else {
+		false
+	}
+}
+
+pub fn build(
+	mut module: elements::Module,
+	source_target: SourceTarget,
+	runtime_type_version: Option<([u8; 4], u32)>,
+	public_api_entries: &[&str],
+	enforce_stack_adjustment: bool,
+	stack_size: u32,
+	skip_optimization: bool,
+	target_runtime: &TargetRuntime,
+) -> Result<(elements::Module, Option<elements::Module>), Error> {
+
+	if let SourceTarget::Emscripten = source_target {
+		module = ununderscore_funcs(module);
+	}
+
+	if let SourceTarget::Unknown = source_target {
+		// 49152 is 48kb!
+		if enforce_stack_adjustment {
+			assert!(stack_size <= 1024*1024);
+			let (new_module, new_stack_top) = shrink_unknown_stack(module, 1024 * 1024 - stack_size);
+			module = new_module;
+			let mut stack_top_page = new_stack_top / 65536;
+			if new_stack_top % 65536 > 0 { stack_top_page += 1 };
+			module = externalize_mem(module, Some(stack_top_page), 16);
+		} else {
+			module = externalize_mem(module, None, 16);
+		}
+	}
+
+	if let Some(runtime_type_version) = runtime_type_version {
+		let (runtime_type, runtime_version) = runtime_type_version;
+		module = inject_runtime_type(module, runtime_type, runtime_version);
+	}
+
+	let mut ctor_module = module.clone();
+
+	let mut public_api_entries = public_api_entries.to_vec();
+	public_api_entries.push(target_runtime.call_symbol);
+	if !skip_optimization {
+		optimize(
+			&mut module,
+			public_api_entries,
+		)?;
+	}
+
+	if has_ctor(&ctor_module, target_runtime) {
+		if !skip_optimization {
+			optimize(&mut ctor_module, vec![target_runtime.create_symbol])?;
+		}
+		let ctor_module = pack_instance(
+			parity_wasm::serialize(module.clone()).map_err(Error::Encoding)?,
+			ctor_module.clone(),
+			target_runtime,
+		)?;
+		Ok((module, Some(ctor_module)))
+	} else {
+		Ok((module, None))
+	}
+}

src/ext.rs

@@ -8,29 +8,23 @@ use byteorder::{LittleEndian, ByteOrder};
 
 type Insertion = (usize, u32, u32, String);
 
-pub fn update_call_index(opcodes: &mut elements::Opcodes, original_imports: usize, inserts: &[Insertion]) {
-	use parity_wasm::elements::Opcode::*;
-	for opcode in opcodes.elements_mut().iter_mut() {
-		match opcode {
-			&mut Call(ref mut call_index) => {
-				if let Some(pos) = inserts.iter().position(|x| x.1 == *call_index) {
-					*call_index = (original_imports + pos) as u32;
-				} else if *call_index as usize > original_imports {
-					*call_index += inserts.len() as u32;
-				}
-			},
-			_ => { }
+pub fn update_call_index(instructions: &mut elements::Instructions, original_imports: usize, inserts: &[Insertion]) {
+	use parity_wasm::elements::Instruction::*;
+	for instruction in instructions.elements_mut().iter_mut() {
+		if let &mut Call(ref mut call_index) = instruction {
+			if let Some(pos) = inserts.iter().position(|x| x.1 == *call_index) {
+				*call_index = (original_imports + pos) as u32;
+			} else if *call_index as usize > original_imports {
+				*call_index += inserts.len() as u32;
+			}
 		}
 	}
 }
 
 pub fn memory_section<'a>(module: &'a mut elements::Module) -> Option<&'a mut elements::MemorySection> {
-   for section in module.sections_mut() {
-		match section {
-			&mut elements::Section::Memory(ref mut sect) => {
-				return Some(sect);
-			},
-			_ => { }
+	for section in module.sections_mut() {
+	   if let &mut elements::Section::Memory(ref mut sect) = section {
+		   return Some(sect);
 		}
 	}
 	None
@@ -104,7 +98,7 @@ pub fn shrink_unknown_stack(
 		match section {
 			&mut elements::Section::Data(ref mut data_section) => {
 				for ref mut data_segment in data_section.entries_mut() {
-					if data_segment.offset().code() == &[elements::Opcode::I32Const(4), elements::Opcode::End] {
+					if data_segment.offset().code() == &[elements::Instruction::I32Const(4), elements::Instruction::End] {
 						assert_eq!(data_segment.value().len(), 4);
 						let current_val = LittleEndian::read_u32(data_segment.value());
 						let new_val = current_val - shrink_amount;
@@ -182,11 +176,8 @@ pub fn externalize(
 			},
 			&mut elements::Section::Export(ref mut export_section) => {
 				for ref mut export in export_section.entries_mut() {
-					match export.internal_mut() {
-						&mut elements::Internal::Function(ref mut func_index) => {
-							if *func_index >= import_funcs_total as u32 { *func_index += replaces.len() as u32; }
-						},
-						_ => {}
+					if let &mut elements::Internal::Function(ref mut func_index) = export.internal_mut() {
+						if *func_index >= import_funcs_total as u32 { *func_index += replaces.len() as u32; }
 					}
 				}
 			},

src/gas.rs

@@ -3,14 +3,11 @@ use std::vec::Vec;
 use parity_wasm::{elements, builder};
 use rules;
 
-pub fn update_call_index(opcodes: &mut elements::Opcodes, inserted_index: u32) {
-	use parity_wasm::elements::Opcode::*;
-	for opcode in opcodes.elements_mut().iter_mut() {
-		match opcode {
-			&mut Call(ref mut call_index) => {
-				if *call_index >= inserted_index { *call_index += 1}
-			},
-			_ => { },
+pub fn update_call_index(instructions: &mut elements::Instructions, inserted_index: u32) {
+	use parity_wasm::elements::Instruction::*;
+	for instruction in instructions.elements_mut().iter_mut() {
+		if let &mut Call(ref mut call_index) = instruction {
+			if *call_index >= inserted_index { *call_index += 1}
 		}
 	}
 }
@@ -86,30 +83,27 @@ impl Counter {
 	}
 }
 
-fn inject_grow_counter(opcodes: &mut elements::Opcodes, grow_counter_func: u32) -> usize {
-	use parity_wasm::elements::Opcode::*;
+fn inject_grow_counter(instructions: &mut elements::Instructions, grow_counter_func: u32) -> usize {
+	use parity_wasm::elements::Instruction::*;
 	let mut counter = 0;
-	for opcode in opcodes.elements_mut() {
-		match *opcode {
-			GrowMemory(_) => {
-				*opcode = Call(grow_counter_func);
-				counter += 1;
-			},
-			_ => {}
+	for instruction in instructions.elements_mut() {
+		if let GrowMemory(_) = *instruction {
+			*instruction = Call(grow_counter_func);
+			counter += 1;
 		}
 	}
 	counter
 }
 
 fn add_grow_counter(module: elements::Module, rules: &rules::Set, gas_func: u32) -> elements::Module {
-	use parity_wasm::elements::Opcode::*;
+	use parity_wasm::elements::Instruction::*;
 
 	let mut b = builder::from_module(module);
 	b.push_function(
 		builder::function()
 			.signature().params().i32().build().with_return_type(Some(elements::ValueType::I32)).build()
 			.body()
-				.with_opcodes(elements::Opcodes::new(vec![
+				.with_instructions(elements::Instructions::new(vec![
 					GetLocal(0),
 					GetLocal(0),
 					I32Const(rules.grow_cost() as i32),
@@ -127,24 +121,24 @@ fn add_grow_counter(module: elements::Module, rules: &rules::Set, gas_func: u32)
 }
 
 pub fn inject_counter(
-	opcodes: &mut elements::Opcodes,
+	instructions: &mut elements::Instructions,
 	rules: &rules::Set,
 	gas_func: u32,
 ) -> Result<(), ()> {
-	use parity_wasm::elements::Opcode::*;
+	use parity_wasm::elements::Instruction::*;
 
 	let mut counter = Counter::new();
 
 	// Begin an implicit function (i.e. `func...end`) block.
 	counter.begin(0);
 
-	for cursor in 0..opcodes.elements().len() {
-		let opcode = &opcodes.elements()[cursor];
-		match *opcode {
+	for cursor in 0..instructions.elements().len() {
+		let instruction = &instructions.elements()[cursor];
+		match *instruction {
 			Block(_) | If(_) | Loop(_) => {
 				// Increment previous block with the cost of the current opcode.
-				let opcode_cost = rules.process(opcode)?;
-				counter.increment(opcode_cost)?;
+				let instruction_cost = rules.process(instruction)?;
+				counter.increment(instruction_cost)?;
 
 				// Begin new block. The cost of the following opcodes until `End` or `Else` will
 				// be included into this block.
@@ -170,8 +164,8 @@ pub fn inject_counter(
 			}
 			_ => {
 				// An ordinal non control flow instruction. Just increment the cost of the current block.
-				let opcode_cost = rules.process(opcode)?;
-				counter.increment(opcode_cost)?;
+				let instruction_cost = rules.process(instruction)?;
+				counter.increment(instruction_cost)?;
 			}
 		}
 	}
@@ -181,8 +175,8 @@ pub fn inject_counter(
 	for block in counter.blocks {
 		let effective_pos = block.start_pos + cumulative_offset;
 
-		opcodes.elements_mut().insert(effective_pos, I32Const(block.cost as i32));
-		opcodes.elements_mut().insert(effective_pos+1, Call(gas_func));
+		instructions.elements_mut().insert(effective_pos, I32Const(block.cost as i32));
+		instructions.elements_mut().insert(effective_pos+1, Call(gas_func));
 
 		// Take into account these two inserted instructions.
 		cumulative_offset += 2;
@@ -244,11 +238,8 @@ pub fn inject_gas_counter(module: elements::Module, rules: &rules::Set)
 			},
 			&mut elements::Section::Export(ref mut export_section) => {
 				for ref mut export in export_section.entries_mut() {
-					match export.internal_mut() {
-						&mut elements::Internal::Function(ref mut func_index) => {
-							if *func_index >= gas_func { *func_index += 1}
-						},
-						_ => {}
+					if let &mut elements::Internal::Function(ref mut func_index) = export.internal_mut() {
+						if *func_index >= gas_func { *func_index += 1}
 					}
 				}
 			},
@@ -260,6 +251,9 @@ pub fn inject_gas_counter(module: elements::Module, rules: &rules::Set)
 					}
 				}
 			},
+			&mut elements::Section::Start(ref mut start_idx) => {
+				if *start_idx >= gas_func { *start_idx += 1}
+			},
 			_ => { }
 		}
 	}
@@ -280,7 +274,7 @@ mod tests {
 
 	#[test]
 	fn simple_grow() {
-		use parity_wasm::elements::Opcode::*;
+		use parity_wasm::elements::Instruction::*;
 
 		let module = builder::module()
 			.global()
@@ -289,7 +283,7 @@ mod tests {
 			.function()
 				.signature().param().i32().build()
 				.body()
-					.with_opcodes(elements::Opcodes::new(
+					.with_instructions(elements::Instructions::new(
 						vec![
 							GetGlobal(0),
 							GrowMemory(0),
@@ -335,7 +329,7 @@ mod tests {
 
 	#[test]
 	fn grow_no_gas_no_track() {
-		use parity_wasm::elements::Opcode::*;
+		use parity_wasm::elements::Instruction::*;
 
 		let module = builder::module()
 			.global()
@@ -344,7 +338,7 @@ mod tests {
 			.function()
 				.signature().param().i32().build()
 				.body()
-					.with_opcodes(elements::Opcodes::new(
+					.with_instructions(elements::Instructions::new(
 						vec![
 							GetGlobal(0),
 							GrowMemory(0),
@@ -378,7 +372,7 @@ mod tests {
 
 	#[test]
 	fn simple() {
-		use parity_wasm::elements::Opcode::*;
+		use parity_wasm::elements::Instruction::*;
 
 		let module = builder::module()
 			.global()
@@ -387,7 +381,7 @@ mod tests {
 			.function()
 				.signature().param().i32().build()
 				.body()
-					.with_opcodes(elements::Opcodes::new(
+					.with_instructions(elements::Instructions::new(
 						vec![
 							GetGlobal(0),
 							End
@@ -414,7 +408,7 @@ mod tests {
 
 	#[test]
 	fn nested() {
-		use parity_wasm::elements::Opcode::*;
+		use parity_wasm::elements::Instruction::*;
 
 		let module = builder::module()
 			.global()
@@ -423,7 +417,7 @@ mod tests {
 			.function()
 				.signature().param().i32().build()
 				.body()
-					.with_opcodes(elements::Opcodes::new(
+					.with_instructions(elements::Instructions::new(
 						vec![
 							GetGlobal(0),
 							Block(elements::BlockType::NoResult),
@@ -464,7 +458,7 @@ mod tests {
 
 	#[test]
 	fn ifelse() {
-		use parity_wasm::elements::Opcode::*;
+		use parity_wasm::elements::Instruction::*;
 
 		let module = builder::module()
 			.global()
@@ -473,7 +467,7 @@ mod tests {
 			.function()
 				.signature().param().i32().build()
 				.body()
-					.with_opcodes(elements::Opcodes::new(
+					.with_instructions(elements::Instructions::new(
 						vec![
 							GetGlobal(0),
 							If(elements::BlockType::NoResult),
@@ -522,7 +516,7 @@ mod tests {
 
 	#[test]
 	fn call_index() {
-		use parity_wasm::elements::Opcode::*;
+		use parity_wasm::elements::Instruction::*;
 
 		let module = builder::module()
 			.global()
@@ -535,7 +529,7 @@ mod tests {
 			.function()
 				.signature().param().i32().build()
 				.body()
-					.with_opcodes(elements::Opcodes::new(
+					.with_instructions(elements::Instructions::new(
 						vec![
 							Call(0),
 							If(elements::BlockType::NoResult),
@@ -585,7 +579,7 @@ mod tests {
 
 	#[test]
 	fn forbidden() {
-		use parity_wasm::elements::Opcode::*;
+		use parity_wasm::elements::Instruction::*;
 
 		let module = builder::module()
 			.global()
@@ -594,7 +588,7 @@ mod tests {
 			.function()
 				.signature().param().i32().build()
 				.body()
-					.with_opcodes(elements::Opcodes::new(
+					.with_instructions(elements::Instructions::new(
 						vec![
 							F32Const(555555),
 							End

src/lib.rs

@@ -9,12 +9,9 @@ extern crate parity_wasm;
 extern crate byteorder;
 #[macro_use] extern crate log;
 
-pub static CREATE_SYMBOL: &'static str = "deploy";
-pub static CALL_SYMBOL: &'static str = "call";
-pub static RET_SYMBOL: &'static str = "ret";
-
 pub mod rules;
 
+mod build;
 mod optimizer;
 mod gas;
 mod symbols;
@@ -24,18 +21,43 @@ mod runtime_type;
 
 pub mod stack_height;
 
+pub use build::{build, SourceTarget, Error as BuildError};
 pub use optimizer::{optimize, Error as OptimizerError};
 pub use gas::inject_gas_counter;
 pub use ext::{externalize, externalize_mem, underscore_funcs, ununderscore_funcs, shrink_unknown_stack};
 pub use pack::{pack_instance, Error as PackingError};
 pub use runtime_type::inject_runtime_type;
 
+pub struct TargetRuntime {
+	pub create_symbol: &'static str,
+	pub call_symbol: &'static str,
+	pub return_symbol: &'static str,
+}
+
+impl TargetRuntime {
+	pub fn substrate() -> TargetRuntime {
+		TargetRuntime {
+			create_symbol: "deploy",
+			call_symbol: "call",
+			return_symbol: "ext_return",
+		}
+	}
+
+	pub fn pwasm() -> TargetRuntime {
+		TargetRuntime {
+			create_symbol: "deploy",
+			call_symbol: "call",
+			return_symbol: "ret",
+		}
+	}
+}
+
 #[cfg(not(feature = "std"))]
 mod std {
 	pub use core::*;
 	pub use alloc::{vec, string, boxed, borrow};
 
 	pub mod collections {
-		pub use alloc::{BTreeMap, BTreeSet};
+		pub use alloc::collections::{BTreeMap, BTreeSet};
 	}
 }

src/optimizer.rs

@@ -270,25 +270,22 @@ pub fn optimize(
 }
 
 
-pub fn update_call_index(opcodes: &mut elements::Opcodes, eliminated_indices: &[usize]) {
-	use parity_wasm::elements::Opcode::*;
-	for opcode in opcodes.elements_mut().iter_mut() {
-		match opcode {
-			&mut Call(ref mut call_index) => {
-				let totalle = eliminated_indices.iter().take_while(|i| (**i as u32) < *call_index).count();
-				trace!("rewired call {} -> call {}", *call_index, *call_index - totalle as u32);
-				*call_index -= totalle as u32;
-			},
-			_ => { },
+pub fn update_call_index(instructions: &mut elements::Instructions, eliminated_indices: &[usize]) {
+	use parity_wasm::elements::Instruction::*;
+	for instruction in instructions.elements_mut().iter_mut() {
+		if let &mut Call(ref mut call_index) = instruction {
+			let totalle = eliminated_indices.iter().take_while(|i| (**i as u32) < *call_index).count();
+			trace!("rewired call {} -> call {}", *call_index, *call_index - totalle as u32);
+			*call_index -= totalle as u32;
 		}
 	}
 }
 
 /// Updates global references considering the _ordered_ list of eliminated indices
-pub fn update_global_index(opcodes: &mut Vec<elements::Opcode>, eliminated_indices: &[usize]) {
-	use parity_wasm::elements::Opcode::*;
-	for opcode in opcodes.iter_mut() {
-		match opcode {
+pub fn update_global_index(instructions: &mut Vec<elements::Instruction>, eliminated_indices: &[usize]) {
+	use parity_wasm::elements::Instruction::*;
+	for instruction in instructions.iter_mut() {
+		match instruction {
 			&mut GetGlobal(ref mut index) | &mut SetGlobal(ref mut index) => {
 				let totalle = eliminated_indices.iter().take_while(|i| (**i as u32) < *index).count();
 				trace!("rewired global {} -> global {}", *index, *index - totalle as u32);
@@ -300,27 +297,21 @@ pub fn update_global_index(opcodes: &mut Vec<elements::Opcode>, eliminated_indic
 }
 
 /// Updates global references considering the _ordered_ list of eliminated indices
-pub fn update_type_index(opcodes: &mut elements::Opcodes, eliminated_indices: &[usize]) {
-	use parity_wasm::elements::Opcode::*;
-	for opcode in opcodes.elements_mut().iter_mut() {
-		match opcode {
-			&mut CallIndirect(ref mut call_index, _) => {
-				let totalle = eliminated_indices.iter().take_while(|i| (**i as u32) < *call_index).count();
-				trace!("rewired call_indrect {} -> call_indirect {}", *call_index, *call_index - totalle as u32);
-				*call_index -= totalle as u32;
-			},
-			_ => { },
+pub fn update_type_index(instructions: &mut elements::Instructions, eliminated_indices: &[usize]) {
+	use parity_wasm::elements::Instruction::*;
+	for instruction in instructions.elements_mut().iter_mut() {
+		if let &mut CallIndirect(ref mut call_index, _) = instruction {
+			let totalle = eliminated_indices.iter().take_while(|i| (**i as u32) < *call_index).count();
+			trace!("rewired call_indrect {} -> call_indirect {}", *call_index, *call_index - totalle as u32);
+			*call_index -= totalle as u32;
 		}
 	}
 }
 
 pub fn import_section<'a>(module: &'a mut elements::Module) -> Option<&'a mut elements::ImportSection> {
    for section in module.sections_mut() {
-		match section {
-			&mut elements::Section::Import(ref mut sect) => {
-				return Some(sect);
-			},
-			_ => { }
+		if let &mut elements::Section::Import(ref mut sect) = section {
+			return Some(sect);
 		}
 	}
 	None
@@ -328,11 +319,8 @@ pub fn import_section<'a>(module: &'a mut elements::Module) -> Option<&'a mut el
 
 pub fn global_section<'a>(module: &'a mut elements::Module) -> Option<&'a mut elements::GlobalSection> {
    for section in module.sections_mut() {
-		match section {
-			&mut elements::Section::Global(ref mut sect) => {
-				return Some(sect);
-			},
-			_ => { }
+		if let &mut elements::Section::Global(ref mut sect) = section {
+			return Some(sect);
 		}
 	}
 	None
@@ -340,11 +328,8 @@ pub fn global_section<'a>(module: &'a mut elements::Module) -> Option<&'a mut el
 
 pub fn function_section<'a>(module: &'a mut elements::Module) -> Option<&'a mut elements::FunctionSection> {
    for section in module.sections_mut() {
-		match section {
-			&mut elements::Section::Function(ref mut sect) => {
-				return Some(sect);
-			},
-			_ => { }
+		if let &mut elements::Section::Function(ref mut sect) = section {
+			return Some(sect);
 		}
 	}
 	None
@@ -352,11 +337,8 @@ pub fn function_section<'a>(module: &'a mut elements::Module) -> Option<&'a mut
 
 pub fn code_section<'a>(module: &'a mut elements::Module) -> Option<&'a mut elements::CodeSection> {
    for section in module.sections_mut() {
-		match section {
-			&mut elements::Section::Code(ref mut sect) => {
-				return Some(sect);
-			},
-			_ => { }
+		if let &mut elements::Section::Code(ref mut sect) = section {
+			return Some(sect);
 		}
 	}
 	None
@@ -364,11 +346,8 @@ pub fn code_section<'a>(module: &'a mut elements::Module) -> Option<&'a mut elem
 
 pub fn export_section<'a>(module: &'a mut elements::Module) -> Option<&'a mut elements::ExportSection> {
    for section in module.sections_mut() {
-		match section {
-			&mut elements::Section::Export(ref mut sect) => {
-				return Some(sect);
-			},
-			_ => { }
+		if let &mut elements::Section::Export(ref mut sect) = section {
+			return Some(sect);
 		}
 	}
 	None
@@ -376,11 +355,8 @@ pub fn export_section<'a>(module: &'a mut elements::Module) -> Option<&'a mut el
 
 pub fn type_section<'a>(module: &'a mut elements::Module) -> Option<&'a mut elements::TypeSection> {
    for section in module.sections_mut() {
-		match section {
-			&mut elements::Section::Type(ref mut sect) => {
-				return Some(sect);
-			},
-			_ => { }
+		if let &mut elements::Section::Type(ref mut sect) = section {
+			return Some(sect);
 		}
 	}
 	None
@@ -459,10 +435,10 @@ mod tests {
 			.function()
 				.signature().param().i32().build()
 				.body()
-					.with_opcodes(elements::Opcodes::new(
+					.with_instructions(elements::Instructions::new(
 						vec![
-							elements::Opcode::GetGlobal(0),
-							elements::Opcode::End
+							elements::Instruction::GetGlobal(0),
+							elements::Instruction::End
 						]
 					))
 					.build()
@@ -501,10 +477,10 @@ mod tests {
 			.function()
 				.signature().param().i32().build()
 				.body()
-					.with_opcodes(elements::Opcodes::new(
+					.with_instructions(elements::Instructions::new(
 						vec![
-							elements::Opcode::GetGlobal(1),
-							elements::Opcode::End
+							elements::Instruction::GetGlobal(1),
+							elements::Instruction::End
 						]
 					))
 					.build()
@@ -534,10 +510,10 @@ mod tests {
 			.function()
 				.signature().param().i32().build()
 				.body()
-					.with_opcodes(elements::Opcodes::new(
+					.with_instructions(elements::Instructions::new(
 						vec![
-							elements::Opcode::Call(1),
-							elements::Opcode::End
+							elements::Instruction::Call(1),
+							elements::Instruction::End
 						]
 					))
 					.build()
@@ -582,15 +558,15 @@ mod tests {
 				.signature().param().i32().param().i32().build()
 				.build()
 			.function()
-				.signature().param().i32().param().i32().build()
+				.signature().param().i32().param().i32().param().i32().build()
 				.build()
 			.function()
 				.signature().param().i32().build()
 				.body()
-					.with_opcodes(elements::Opcodes::new(
+					.with_instructions(elements::Instructions::new(
 						vec![
-							elements::Opcode::CallIndirect(1, 0),
-							elements::Opcode::End
+							elements::Instruction::CallIndirect(1, 0),
+							elements::Instruction::End
 						]
 					))
 					.build()
@@ -610,7 +586,7 @@ mod tests {
 
 		let indirect_opcode = &module.code_section().expect("code section to be generated").bodies()[0].code().elements()[0];
 		match *indirect_opcode {
-			elements::Opcode::CallIndirect(0, 0) => {},
+			elements::Instruction::CallIndirect(0, 0) => {},
 			_ => {
 				panic!(
 					"Expected call_indirect to use index 0 after optimization, since previois 0th was eliminated, but got {:?}",

src/pack.rs

@@ -3,11 +3,11 @@ use std::vec::Vec;
 use std::borrow::ToOwned;
 
 use parity_wasm::elements::{
-    self, Section, DataSection, Opcode, DataSegment, InitExpr, Internal, External,
+    self, Section, DataSection, Instruction, DataSegment, InitExpr, Internal, External,
     ImportCountType,
 };
 use parity_wasm::builder;
-use super::{CREATE_SYMBOL, CALL_SYMBOL, RET_SYMBOL};
+use super::TargetRuntime;
 use super::gas::update_call_index;
 
 /// Pack error.
@@ -20,9 +20,9 @@ pub enum Error {
     NoTypeSection,
     NoExportSection,
     NoCodeSection,
-    InvalidCreateSignature,
-    NoCreateSymbol,
-    InvalidCreateMember,
+    InvalidCreateSignature(&'static str),
+    NoCreateSymbol(&'static str),
+    InvalidCreateMember(&'static str),
     NoImportSection,
 }
 
@@ -33,37 +33,37 @@ impl fmt::Display for Error {
             Error::NoTypeSection => write!(f, "No type section in the module"),
             Error::NoExportSection => write!(f, "No export section in the module"),
             Error::NoCodeSection => write!(f, "No code section inthe module"),
-            Error::InvalidCreateSignature => write!(f, "Exported symbol `deploy` has invalid signature, should be () -> ()"),
-            Error::InvalidCreateMember => write!(f, "Exported symbol `deploy` should be a function"),
-            Error::NoCreateSymbol => write!(f, "No exported `deploy` symbol"),
+            Error::InvalidCreateSignature(sym) => write!(f, "Exported symbol `{}` has invalid signature, should be () -> ()", sym),
+            Error::InvalidCreateMember(sym) => write!(f, "Exported symbol `{}` should be a function", sym),
+            Error::NoCreateSymbol(sym) => write!(f, "No exported `{}` symbol", sym),
             Error::NoImportSection => write!(f, "No import section in the module"),
         }
     }
 }
 
-/// If module has an exported "_create" function we want to pack it into "constructor".
+/// If module has an exported "CREATE_SYMBOL" function we want to pack it into "constructor".
 /// `raw_module` is the actual contract code
 /// `ctor_module` is the constructor which should return `raw_module`
-pub fn pack_instance(raw_module: Vec<u8>, mut ctor_module: elements::Module) -> Result<elements::Module, Error> {
+pub fn pack_instance(raw_module: Vec<u8>, mut ctor_module: elements::Module, target: &TargetRuntime) -> Result<elements::Module, Error> {
 
     // Total number of constructor module import functions
     let ctor_import_functions = ctor_module.import_section().map(|x| x.functions()).unwrap_or(0);
 
-    // We need to find an internal ID of function witch is exported as "_create"
+    // We need to find an internal ID of function witch is exported as "CREATE_SYMBOL"
     // in order to find it in the Code section of the module
     let mut create_func_id = {
         let found_entry = ctor_module.export_section().ok_or(Error::NoExportSection)?.entries().iter()
-            .find(|entry| CREATE_SYMBOL == entry.field()).ok_or(Error::NoCreateSymbol)?;
+            .find(|entry| target.create_symbol == entry.field()).ok_or_else(|| Error::NoCreateSymbol(target.create_symbol))?;
 
         let function_index: usize = match found_entry.internal() {
             &Internal::Function(index) => index as usize,
-            _ => { return Err(Error::InvalidCreateMember) },
+            _ => { return Err(Error::InvalidCreateMember(target.create_symbol)) },
         };
 
         // Calculates a function index within module's function section
         let function_internal_index = function_index - ctor_import_functions;
 
-        // Constructor should be of signature `func(i32)` (void), fail otherwise
+        // Constructor should be of signature `func()` (void), fail otherwise
         let type_id = ctor_module.function_section().ok_or(Error::NoCodeSection)?
             .entries().get(function_index - ctor_import_functions).ok_or(Error::MalformedModule)?
             .type_ref();
@@ -73,10 +73,10 @@ pub fn pack_instance(raw_module: Vec<u8>, mut ctor_module: elements::Module) ->
 
         // Deploy should have no arguments and also should return nothing
         if !func.params().is_empty() {
-            return Err(Error::InvalidCreateSignature);
+            return Err(Error::InvalidCreateSignature(target.create_symbol));
         }
         if func.return_type().is_some() {
-            return Err(Error::InvalidCreateSignature);
+            return Err(Error::InvalidCreateSignature(target.create_symbol));
         }
 
         function_internal_index
@@ -87,7 +87,7 @@ pub fn pack_instance(raw_module: Vec<u8>, mut ctor_module: elements::Module) ->
         let mut found = false;
         for entry in ctor_module.import_section().ok_or(Error::NoImportSection)?.entries().iter() {
             if let External::Function(_) = *entry.external() {
-                if entry.field() == RET_SYMBOL { found = true; break; }
+                if entry.field() == target.return_symbol { found = true; break; }
                 else { id += 1; }
             }
         }
@@ -102,7 +102,7 @@ pub fn pack_instance(raw_module: Vec<u8>, mut ctor_module: elements::Module) ->
             mbuilder.push_import(
                 builder::import()
                     .module("env")
-                    .field("ret")
+                    .field(&target.return_symbol)
                     .external().func(import_sig)
                     .build()
                 );
@@ -120,11 +120,8 @@ pub fn pack_instance(raw_module: Vec<u8>, mut ctor_module: elements::Module) ->
                     },
                     elements::Section::Export(ref mut export_section) => {
                         for ref mut export in export_section.entries_mut() {
-                            match export.internal_mut() {
-                                &mut elements::Internal::Function(ref mut func_index) => {
-                                    if *func_index >= ret_func { *func_index += 1}
-                                },
-                                _ => {}
+                            if let &mut elements::Internal::Function(ref mut func_index) = export.internal_mut() {
+                                if *func_index >= ret_func { *func_index += 1}
                             }
                         }
                     },
@@ -163,57 +160,51 @@ pub fn pack_instance(raw_module: Vec<u8>, mut ctor_module: elements::Module) ->
     let mut code_data_address = 0i32;
 
     for section in ctor_module.sections_mut() {
-        match section {
-            &mut Section::Data(ref mut data_section) => {
-                let (index, offset) = if let Some(ref entry) = data_section.entries().iter().last() {
-                    if let Opcode::I32Const(offst) = entry.offset().code()[0] {
-                        let len = entry.value().len() as i32;
-                        let offst = offst as i32;
-                        (entry.index(), offst + (len + 4) - len % 4)
-                    } else {
-                        (0, 0)
-                    }
+        if let &mut Section::Data(ref mut data_section) = section {
+            let (index, offset) = if let Some(ref entry) = data_section.entries().iter().last() {
+                if let Instruction::I32Const(offst) = entry.offset().code()[0] {
+                    let len = entry.value().len() as i32;
+                    let offst = offst as i32;
+                    (entry.index(), offst + (len + 4) - len % 4)
                 } else {
                     (0, 0)
-                };
-                let code_data = DataSegment::new(
-                    index,
-                    InitExpr::new(vec![Opcode::I32Const(offset), Opcode::End]),
-                    raw_module.clone()
-                );
-                data_section.entries_mut().push(code_data);
-                code_data_address = offset;
-            },
-            _ => {;}
+                }
+            } else {
+                (0, 0)
+            };
+            let code_data = DataSegment::new(
+                index,
+                InitExpr::new(vec![Instruction::I32Const(offset), Instruction::End]),
+                raw_module.clone()
+            );
+            data_section.entries_mut().push(code_data);
+            code_data_address = offset;
         }
     }
 
     let mut new_module = builder::from_module(ctor_module)
         .function()
         .signature().build()
-        .body().with_opcodes(elements::Opcodes::new(
+        .body().with_instructions(elements::Instructions::new(
             vec![
-                Opcode::Call((create_func_id + ctor_import_functions) as u32),
-                Opcode::I32Const(code_data_address),
-                Opcode::I32Const(raw_module.len() as i32),
-                Opcode::Call(ret_function_id as u32),
-                Opcode::End,
+                Instruction::Call((create_func_id + ctor_import_functions) as u32),
+                Instruction::I32Const(code_data_address),
+                Instruction::I32Const(raw_module.len() as i32),
+                Instruction::Call(ret_function_id as u32),
+                Instruction::End,
             ])).build()
             .build()
         .build();
 
     for section in new_module.sections_mut() {
-        match section {
-            &mut Section::Export(ref mut export_section) => {
-                for entry in export_section.entries_mut().iter_mut() {
-                    if CREATE_SYMBOL == entry.field() {
-                        // change _create export name into default _call
-                        *entry.field_mut() = CALL_SYMBOL.to_owned();
-                        *entry.internal_mut() = elements::Internal::Function(last_function_index as u32);
-                    }
+        if let &mut Section::Export(ref mut export_section) = section {
+            for entry in export_section.entries_mut().iter_mut() {
+                if target.create_symbol == entry.field() {
+                    // change `create_symbol` export name into default `call_symbol`.
+                    *entry.field_mut() = target.call_symbol.to_owned();
+                    *entry.internal_mut() = elements::Internal::Function(last_function_index as u32);
                 }
-            },
-            _ => { },
+            }
         }
     };
 
@@ -228,13 +219,13 @@ mod test {
     use super::*;
     use super::super::optimize;
 
-    fn test_packer(mut module: elements::Module) {
+    fn test_packer(mut module: elements::Module, target_runtime: &TargetRuntime) {
         let mut ctor_module = module.clone();
-        optimize(&mut module, vec![CALL_SYMBOL]).expect("Optimizer to finish without errors");
-        optimize(&mut ctor_module, vec![CREATE_SYMBOL]).expect("Optimizer to finish without errors");
+        optimize(&mut module, vec![target_runtime.call_symbol]).expect("Optimizer to finish without errors");
+        optimize(&mut ctor_module, vec![target_runtime.create_symbol]).expect("Optimizer to finish without errors");
 
         let raw_module = parity_wasm::serialize(module).unwrap();
-        let ctor_module = pack_instance(raw_module.clone(), ctor_module).expect("Packing failed");
+        let ctor_module = pack_instance(raw_module.clone(), ctor_module, target_runtime).expect("Packing failed");
 
         let data_section = ctor_module.data_section().expect("Packed module has to have a data section");
         let data_segment = data_section.entries().iter().last().expect("Packed module has to have a data section with at least one entry");
@@ -243,6 +234,8 @@ mod test {
 
     #[test]
     fn no_data_section() {
+		let target_runtime = TargetRuntime::pwasm();
+
         test_packer(builder::module()
             .import()
                 .module("env")
@@ -258,9 +251,9 @@ mod test {
             .function()
                 .signature().build()
                 .body()
-                    .with_opcodes(elements::Opcodes::new(
+                    .with_instructions(elements::Instructions::new(
                         vec![
-                            elements::Opcode::End
+                            elements::Instruction::End
                         ]
                     ))
                     .build()
@@ -268,27 +261,30 @@ mod test {
             .function()
                 .signature().build()
                 .body()
-                    .with_opcodes(elements::Opcodes::new(
+                    .with_instructions(elements::Instructions::new(
                         vec![
-                            elements::Opcode::End
+                            elements::Instruction::End
                         ]
                     ))
                     .build()
             .build()
             .export()
-                .field(CALL_SYMBOL)
+                .field(target_runtime.call_symbol)
                 .internal().func(1)
             .build()
             .export()
-                .field(CREATE_SYMBOL)
+                .field(target_runtime.create_symbol)
                 .internal().func(2)
             .build()
-        .build()
+        .build(),
+			&target_runtime,
         );
     }
 
     #[test]
     fn with_data_section() {
+		let target_runtime = TargetRuntime::pwasm();
+
         test_packer(builder::module()
             .import()
                 .module("env")
@@ -296,7 +292,7 @@ mod test {
                 .external().memory(1 as u32, Some(1 as u32))
                 .build()
             .data()
-                .offset(elements::Opcode::I32Const(16)).value(vec![0u8])
+                .offset(elements::Instruction::I32Const(16)).value(vec![0u8])
                 .build()
             .function()
                 .signature()
@@ -307,9 +303,9 @@ mod test {
             .function()
                 .signature().build()
                 .body()
-                    .with_opcodes(elements::Opcodes::new(
+                    .with_instructions(elements::Instructions::new(
                         vec![
-                            elements::Opcode::End
+                            elements::Instruction::End
                         ]
                     ))
                     .build()
@@ -317,22 +313,23 @@ mod test {
             .function()
                 .signature().build()
                 .body()
-                    .with_opcodes(elements::Opcodes::new(
+                    .with_instructions(elements::Instructions::new(
                         vec![
-                            elements::Opcode::End
+                            elements::Instruction::End
                         ]
                     ))
                     .build()
             .build()
             .export()
-                .field(CALL_SYMBOL)
+                .field(target_runtime.call_symbol)
                 .internal().func(1)
             .build()
             .export()
-                .field(CREATE_SYMBOL)
+                .field(target_runtime.create_symbol)
                 .internal().func(2)
             .build()
-        .build()
+        .build(),
+			&target_runtime,
         );
     }
 }

src/rules.rs

@@ -62,7 +62,7 @@ impl ::std::str::FromStr for InstructionType {
             "reinterpret" => Ok(InstructionType::Reinterpretation),
             "unreachable" => Ok(InstructionType::Unreachable),
             "nop" => Ok(InstructionType::Nop),
-            "currrent_mem" => Ok(InstructionType::CurrentMemory),
+            "current_mem" => Ok(InstructionType::CurrentMemory),
             "grow_mem" => Ok(InstructionType::GrowMemory),
             _ => Err(UnknownInstruction),
         }
@@ -70,10 +70,10 @@ impl ::std::str::FromStr for InstructionType {
 }
 
 impl InstructionType {
-    pub fn op(opcode: &elements::Opcode) -> Self {
-        use parity_wasm::elements::Opcode::*;
+    pub fn op(instruction: &elements::Instruction) -> Self {
+        use parity_wasm::elements::Instruction::*;
 
-        match *opcode {
+        match *instruction {
             Unreachable => InstructionType::Unreachable,
             Nop => InstructionType::Nop,
             Block(_) => InstructionType::ControlFlow,
@@ -288,8 +288,8 @@ impl Set {
         Set { regular: regular, entries: entries, grow: 0 }
     }
 
-    pub fn process(&self, opcode: &elements::Opcode) -> Result<u32, ()>  {
-        match self.entries.get(&InstructionType::op(opcode)).map(|x| *x) {
+    pub fn process(&self, instruction: &elements::Instruction) -> Result<u32, ()>  {
+        match self.entries.get(&InstructionType::op(instruction)).map(|x| *x) {
             None | Some(Metering::Regular) => Ok(self.regular),
             Some(Metering::Forbidden) => Err(()),
             Some(Metering::Fixed(val)) => Ok(val),

src/runtime_type.rs

@@ -1,8 +1,8 @@
 use parity_wasm::{elements, builder};
-use self::elements::{ Module, GlobalEntry, External, ExportEntry, GlobalType, ValueType, InitExpr, Opcode, Internal };
+use self::elements::{ Module, GlobalEntry, External, ExportEntry, GlobalType, ValueType, InitExpr, Instruction, Internal };
 use byteorder::{ LittleEndian, ByteOrder };
 
-pub fn inject_runtime_type(module: Module, runtime_type: &[u8], runtime_version: u32) -> Module {
+pub fn inject_runtime_type(module: Module, runtime_type: [u8; 4], runtime_version: u32) -> Module {
 	let runtime_type: u32 = LittleEndian::read_u32(&runtime_type);
 	let globals_count: u32 = match module.global_section() {
 		Some(ref section) => section.entries().len() as u32,
@@ -18,9 +18,9 @@ pub fn inject_runtime_type(module: Module, runtime_type: &[u8], runtime_version:
 	let total_globals_count: u32 = globals_count + imported_globals_count;
 
 	builder::from_module(module)
-		.with_global(GlobalEntry::new(GlobalType::new(ValueType::I32, false), InitExpr::new(vec![Opcode::I32Const(runtime_type as i32), Opcode::End])))
+		.with_global(GlobalEntry::new(GlobalType::new(ValueType::I32, false), InitExpr::new(vec![Instruction::I32Const(runtime_type as i32), Instruction::End])))
 		.with_export(ExportEntry::new("RUNTIME_TYPE".into(), Internal::Global(total_globals_count)))
-		.with_global(GlobalEntry::new(GlobalType::new(ValueType::I32, false), InitExpr::new(vec![Opcode::I32Const(runtime_version as i32), Opcode::End])))
+		.with_global(GlobalEntry::new(GlobalType::new(ValueType::I32, false), InitExpr::new(vec![Instruction::I32Const(runtime_version as i32), Instruction::End])))
 		.with_export(ExportEntry::new("RUNTIME_VERSION".into(), Internal::Global(total_globals_count + 1)))
 	.build()
 }
@@ -31,9 +31,11 @@ mod tests {
 	#[test]
 	fn it_injects() {
 		let mut module = builder::module()
-			.with_global(GlobalEntry::new(GlobalType::new(ValueType::I32, false), InitExpr::new(vec![Opcode::I32Const(42 as i32)])))
+			.with_global(GlobalEntry::new(GlobalType::new(ValueType::I32, false), InitExpr::new(vec![Instruction::I32Const(42 as i32)])))
 		.build();
-		module = inject_runtime_type(module, b"emcc", 1);
+		let mut runtime_type: [u8; 4] = Default::default();
+		runtime_type.copy_from_slice(b"emcc");
+		module = inject_runtime_type(module, runtime_type, 1);
 		let global_section = module.global_section().expect("Global section expected");
 		assert_eq!(3, global_section.entries().len());
 		let export_section = module.export_section().expect("Export section expected");

src/stack_height/max_height.rs

@@ -136,7 +136,7 @@ impl Stack {
 
 /// This function expects the function to be validated.
 pub(crate) fn compute(func_idx: u32, module: &elements::Module) -> Result<u32, Error> {
-	use parity_wasm::elements::Opcode::*;
+	use parity_wasm::elements::Instruction::*;
 
 	let func_section = module
 		.function_section()
@@ -165,7 +165,7 @@ pub(crate) fn compute(func_idx: u32, module: &elements::Module) -> Result<u32, E
 		.bodies()
 		.get(func_idx as usize)
 		.ok_or_else(|| Error("Function body for the index isn't found".into()))?;
-	let opcodes = body.code();
+	let instructions = body.code();
 
 	let mut stack = Stack::new();
 	let mut max_height: u32 = 0;
@@ -186,7 +186,7 @@ pub(crate) fn compute(func_idx: u32, module: &elements::Module) -> Result<u32, E
 	});
 
 	loop {
-		if pc >= opcodes.elements().len() {
+		if pc >= instructions.elements().len() {
 			break;
 		}
 
@@ -197,7 +197,7 @@ pub(crate) fn compute(func_idx: u32, module: &elements::Module) -> Result<u32, E
 			max_height = stack.height();
 		}
 
-		let opcode = &opcodes.elements()[pc];
+		let opcode = &instructions.elements()[pc];
 		trace!(target: "max_height", "{:?}", opcode);
 
 		match *opcode {

src/stack_height/mod.rs

@@ -25,11 +25,12 @@
 //! Because stack height is increased prior the call few problems arises:
 //!
 //! - Stack height isn't increased upon an entry to the first function, i.e. exported function.
+//! - Start function is executed externally (similar to exported functions).
 //! - It is statically unknown what function will be invoked in an indirect call.
 //!
 //! The solution for this problems is to generate a intermediate functions, called 'thunks', which
 //! will increase before and decrease the stack height after the call to original function, and
-//! then make exported function and table entries to point to a corresponding thunks.
+//! then make exported function and table entries, start section to point to a corresponding thunks.
 //!
 //! # Stack cost
 //!
@@ -57,7 +58,7 @@ use parity_wasm::builder;
 /// Macro to generate preamble and postamble.
 macro_rules! instrument_call {
 	($callee_idx: expr, $callee_stack_cost: expr, $stack_height_global_idx: expr, $stack_limit: expr) => {{
-		use $crate::parity_wasm::elements::Opcode::*;
+		use $crate::parity_wasm::elements::Instruction::*;
 		[
 			// stack_height += stack_cost(F)
 			GetGlobal($stack_height_global_idx),
@@ -160,20 +161,17 @@ fn generate_stack_height_global(ctx: &mut Context, module: &mut elements::Module
 		.value_type()
 		.i32()
 		.mutable()
-		.init_expr(elements::Opcode::I32Const(0))
+		.init_expr(elements::Instruction::I32Const(0))
 		.build();
 
 	// Try to find an existing global section.
 	for section in module.sections_mut() {
-		match *section {
-			elements::Section::Global(ref mut gs) => {
-				gs.entries_mut().push(global_entry);
+		if let elements::Section::Global(ref mut gs) = *section {
+			gs.entries_mut().push(global_entry);
 
-				let stack_height_global_idx = (gs.entries().len() as u32) - 1;
-				ctx.stack_height_global_idx = Some(stack_height_global_idx);
-				return;
-			}
-			_ => {}
+			let stack_height_global_idx = (gs.entries().len() as u32) - 1;
+			ctx.stack_height_global_idx = Some(stack_height_global_idx);
+			return;
 		}
 	}
 
@@ -233,14 +231,11 @@ fn compute_stack_cost(func_idx: u32, module: &elements::Module) -> Result<u32, E
 
 fn instrument_functions(ctx: &mut Context, module: &mut elements::Module) -> Result<(), Error> {
 	for section in module.sections_mut() {
-		match *section {
-			elements::Section::Code(ref mut code_section) => {
-				for func_body in code_section.bodies_mut() {
-					let mut opcodes = func_body.code_mut();
-					instrument_function(ctx, opcodes)?;
-				}
+		if let elements::Section::Code(ref mut code_section) = *section {
+			for func_body in code_section.bodies_mut() {
+				let mut opcodes = func_body.code_mut();
+				instrument_function(ctx, opcodes)?;
 			}
-			_ => {}
 		}
 	}
 	Ok(())
@@ -274,13 +269,13 @@ fn instrument_functions(ctx: &mut Context, module: &mut elements::Module) -> Res
 /// ```
 fn instrument_function(
 	ctx: &mut Context,
-	opcodes: &mut elements::Opcodes,
+	instructions: &mut elements::Instructions,
 ) -> Result<(), Error> {
-	use parity_wasm::elements::Opcode::*;
+	use parity_wasm::elements::Instruction::*;
 
 	let mut cursor = 0;
 	loop {
-		if cursor >= opcodes.elements().len() {
+		if cursor >= instructions.elements().len() {
 			break;
 		}
 
@@ -293,8 +288,8 @@ fn instrument_function(
 		}
 
 		let action: Action = {
-			let opcode = &opcodes.elements()[cursor];
-			match *opcode {
+			let instruction = &instructions.elements()[cursor];
+			match *instruction {
 				Call(ref callee_idx) => {
 					let callee_stack_cost = ctx
 						.stack_cost(*callee_idx)
@@ -336,7 +331,7 @@ fn instrument_function(
 				//
 				// To splice actually take a place, we need to consume iterator
 				// splice returns. So we just `count()` it.
-				let _ = opcodes
+				let _ = instructions
 					.elements_mut()
 					.splice(cursor..(cursor + 1), new_seq.iter().cloned())
 					.count();

src/stack_height/thunk.rs

@@ -35,6 +35,8 @@ pub(crate) fn generate_thunks(
 			.elements_section()
 			.map(|es| es.entries())
 			.unwrap_or(&[]);
+		let start_func_idx = module
+			.start_section();
 
 		let exported_func_indicies = exports.iter().filter_map(|entry| match *entry.internal() {
 			Internal::Function(ref function_idx) => Some(*function_idx),
@@ -48,7 +50,7 @@ pub(crate) fn generate_thunks(
 		// Replacement map is at least export section size.
 		let mut replacement_map: Map<u32, Thunk> = Map::new();
 
-		for func_idx in exported_func_indicies.chain(table_func_indicies) {
+		for func_idx in exported_func_indicies.chain(table_func_indicies).chain(start_func_idx.into_iter()) {
 			let callee_stack_cost = ctx.stack_cost(func_idx).ok_or_else(|| {
 				Error(format!("function with idx {} isn't found", func_idx))
 			})?;
@@ -93,17 +95,17 @@ pub(crate) fn generate_thunks(
 		//  - argument pushing
 		//  - instrumented call
 		//  - end
-		let mut thunk_body: Vec<elements::Opcode> = Vec::with_capacity(
+		let mut thunk_body: Vec<elements::Instruction> = Vec::with_capacity(
 			thunk.signature.params().len() +
 			instrumented_call.len() +
 			1
 		);
 
 		for (arg_idx, _) in thunk.signature.params().iter().enumerate() {
-			thunk_body.push(elements::Opcode::GetLocal(arg_idx as u32));
+			thunk_body.push(elements::Instruction::GetLocal(arg_idx as u32));
 		}
 		thunk_body.extend(instrumented_call.iter().cloned());
-		thunk_body.push(elements::Opcode::End);
+		thunk_body.push(elements::Instruction::End);
 
 		// TODO: Don't generate a signature, but find an existing one.
 
@@ -114,7 +116,7 @@ pub(crate) fn generate_thunks(
 					.with_return_type(thunk.signature.return_type().clone())
 					.build()
 				.body()
-					.with_opcodes(elements::Opcodes::new(
+					.with_instructions(elements::Instructions::new(
 						thunk_body
 					))
 					.build()
@@ -142,9 +144,8 @@ pub(crate) fn generate_thunks(
 		match *section {
 			elements::Section::Export(ref mut export_section) => {
 				for entry in export_section.entries_mut() {
-					match *entry.internal_mut() {
-						Internal::Function(ref mut function_idx) => fixup(function_idx),
-						_ => {}
+					if let Internal::Function(ref mut function_idx) = *entry.internal_mut() {
+						fixup(function_idx)
 					}
 				}
 			}
@@ -155,6 +156,9 @@ pub(crate) fn generate_thunks(
 					}
 				}
 			}
+			elements::Section::Start(ref mut start_idx) => {
+				fixup(start_idx)
+			}
 			_ => {}
 		}
 	}

src/symbols.rs

@@ -19,14 +19,11 @@ pub fn resolve_function(module: &elements::Module, index: u32) -> Symbol {
 	let mut functions = 0;
 	if let Some(import_section) = module.import_section() {
 		for (item_index, item) in import_section.entries().iter().enumerate() {
-			match item.external() {
-				&elements::External::Function(_) => {
-					if functions == index {
-						return Symbol::Import(item_index as usize);
-					}
-					functions += 1;
-				},
-				_ => {}
+			if let &elements::External::Function(_) = item.external() {
+				if functions == index {
+					return Symbol::Import(item_index as usize);
+				}
+				functions += 1;
 			}
 		}
 	}
@@ -38,14 +35,11 @@ pub fn resolve_global(module: &elements::Module, index: u32) -> Symbol {
 	let mut globals = 0;
 	if let Some(import_section) = module.import_section() {
 		for (item_index, item) in import_section.entries().iter().enumerate() {
-			match item.external() {
-				&elements::External::Global(_) => {
-					if globals == index {
-						return Symbol::Import(item_index as usize);
-					}
-					globals += 1;
-				},
-				_ => {}
+			if let &elements::External::Global(_) = item.external() {
+				if globals == index {
+					return Symbol::Import(item_index as usize);
+				}
+				globals += 1;
 			}
 		}
 	}
@@ -53,11 +47,11 @@ pub fn resolve_global(module: &elements::Module, index: u32) -> Symbol {
 	Symbol::Global(index as usize - globals as usize)
 }
 
-pub fn push_code_symbols(module: &elements::Module, opcodes: &[elements::Opcode], dest: &mut Vec<Symbol>) {
-	use parity_wasm::elements::Opcode::*;
+pub fn push_code_symbols(module: &elements::Module, instructions: &[elements::Instruction], dest: &mut Vec<Symbol>) {
+	use parity_wasm::elements::Instruction::*;
 
-	for opcode in opcodes {
-		match opcode {
+	for instruction in instructions {
+		match instruction {
 			&Call(idx) => {
 				dest.push(resolve_function(module, idx));
 			},
@@ -109,15 +103,12 @@ pub fn expand_symbols(module: &elements::Module, set: &mut Set<Symbol>) {
 			},
 			Import(idx) => {
 				let entry = &module.import_section().expect("Import section to exist").entries()[idx];
-				match entry.external() {
-					&elements::External::Function(type_idx) => {
-						let type_symbol = Symbol::Type(type_idx as usize);
-						if !stop.contains(&type_symbol) {
-							fringe.push(type_symbol);
-						}
-						set.insert(type_symbol);
-					},
-					_ => {}
+				if let &elements::External::Function(type_idx) = entry.external() {
+					let type_symbol = Symbol::Type(type_idx as usize);
+					if !stop.contains(&type_symbol) {
+						fringe.push(type_symbol);
+					}
+					set.insert(type_symbol);
 				}
 			},
 			Function(idx) => {

tests/diff.rs

@@ -74,20 +74,47 @@ fn run_diff_test<F: FnOnce(&[u8]) -> Vec<u8>>(test_dir: &str, name: &str, test:
 	}
 }
 
-macro_rules! def_stack_height_test {
-	( $name:ident ) => {
-		#[test]
-		fn $name() {
-			run_diff_test("stack-height", concat!(stringify!($name), ".wat"), |input| {
-				let module = elements::deserialize_buffer(input).expect("Failed to deserialize");
-				let instrumented = utils::stack_height::inject_limiter(module, 1024).expect("Failed to instrument with stack counter");
-				elements::serialize(instrumented).expect("Failed to serialize")
-			});
-		}
-	};
+mod stack_height {
+	use super::*;
+
+	macro_rules! def_stack_height_test {
+		( $name:ident ) => {
+			#[test]
+			fn $name() {
+				run_diff_test("stack-height", concat!(stringify!($name), ".wat"), |input| {
+					let module = elements::deserialize_buffer(input).expect("Failed to deserialize");
+					let instrumented = utils::stack_height::inject_limiter(module, 1024).expect("Failed to instrument with stack counter");
+					elements::serialize(instrumented).expect("Failed to serialize")
+				});
+			}
+		};
+	}
+
+	def_stack_height_test!(simple);
+	def_stack_height_test!(start);
+	def_stack_height_test!(table);
+	def_stack_height_test!(global);
+	def_stack_height_test!(imports);
 }
 
-def_stack_height_test!(simple);
-def_stack_height_test!(table);
-def_stack_height_test!(global);
-def_stack_height_test!(imports);
+mod gas {
+	use super::*;
+
+	macro_rules! def_gas_test {
+		( $name:ident ) => {
+			#[test]
+			fn $name() {
+				run_diff_test("gas", concat!(stringify!($name), ".wat"), |input| {
+					let rules = utils::rules::Set::default();
+
+					let module = elements::deserialize_buffer(input).expect("Failed to deserialize");
+					let instrumented = utils::inject_gas_counter(module, &rules).expect("Failed to instrument with gas metering");
+					elements::serialize(instrumented).expect("Failed to serialize")
+				});
+			}
+		};
+	}
+
+	def_gas_test!(simple);
+	def_gas_test!(start);
+}

tests/expectations/gas/simple.wat

@@ -0,0 +1,26 @@
+(module
+  (type (;0;) (func))
+  (type (;1;) (func (param i32)))
+  (import "env" "gas" (func (;0;) (type 1)))
+  (func (;1;) (type 0)
+    i32.const 3
+    call 0
+    i32.const 1
+    if  ;; label = @1
+      i32.const 2
+      call 0
+      loop  ;; label = @2
+        i32.const 3
+        call 0
+        i32.const 123
+        drop
+      end
+    end)
+  (func (;2;) (type 0)
+    i32.const 2
+    call 0
+    block  ;; label = @1
+      i32.const 1
+      call 0
+    end)
+  (export "simple" (func 1)))

tests/expectations/gas/start.wat

@@ -0,0 +1,20 @@
+(module
+  (type (;0;) (func (param i32 i32)))
+  (type (;1;) (func))
+  (type (;2;) (func (param i32)))
+  (import "env" "ext_return" (func (;0;) (type 0)))
+  (import "env" "memory" (memory (;0;) 1 1))
+  (import "env" "gas" (func (;1;) (type 2)))
+  (func (;2;) (type 1)
+    i32.const 5
+    call 1
+    i32.const 8
+    i32.const 4
+    call 0
+    unreachable)
+  (func (;3;) (type 1)
+    i32.const 1
+    call 1)
+  (export "call" (func 3))
+  (start 2)
+  (data (i32.const 8) "\01\02\03\04"))

tests/expectations/stack-height/global.wat

@@ -2,7 +2,6 @@
   (type (;0;) (func))
   (type (;1;) (func (param i32 i32) (result i32)))
   (type (;2;) (func (param i32)))
-  (type (;3;) (func (param i32 i32) (result i32)))
   (import "env" "foo" (func (;0;) (type 0)))
   (func (;1;) (type 1) (param i32 i32) (result i32)
     get_local 0
@@ -33,7 +32,7 @@
     i32.sub
     set_global 1
     drop)
-  (func (;3;) (type 3) (param i32 i32) (result i32)
+  (func (;3;) (type 1) (param i32 i32) (result i32)
     get_local 0
     get_local 1
     get_global 1

tests/expectations/stack-height/imports.wat

@@ -1,7 +1,6 @@
 (module
   (type (;0;) (func))
   (type (;1;) (func (param i32 i32) (result i32)))
-  (type (;2;) (func (param i32 i32) (result i32)))
   (import "env" "foo" (func (;0;) (type 0)))
   (import "env" "boo" (func (;1;) (type 0)))
   (func (;2;) (type 1) (param i32 i32) (result i32)
@@ -10,7 +9,7 @@
     get_local 0
     get_local 1
     i32.add)
-  (func (;3;) (type 2) (param i32 i32) (result i32)
+  (func (;3;) (type 1) (param i32 i32) (result i32)
     get_local 0
     get_local 1
     get_global 0

tests/expectations/stack-height/simple.wat

@@ -1,10 +1,9 @@
 (module
   (type (;0;) (func))
-  (type (;1;) (func))
   (func (;0;) (type 0)
     i32.const 123
     drop)
-  (func (;1;) (type 1)
+  (func (;1;) (type 0)
     get_global 0
     i32.const 1
     i32.add

tests/expectations/stack-height/start.wat

@@ -0,0 +1,44 @@
+(module
+  (type (;0;) (func (param i32 i32)))
+  (type (;1;) (func))
+  (import "env" "ext_return" (func (;0;) (type 0)))
+  (import "env" "memory" (memory (;0;) 1 1))
+  (func (;1;) (type 1)
+    (local i32))
+  (func (;2;) (type 1))
+  (func (;3;) (type 1)
+    get_global 0
+    i32.const 1
+    i32.add
+    set_global 0
+    get_global 0
+    i32.const 1024
+    i32.gt_u
+    if  ;; label = @1
+      unreachable
+    end
+    call 1
+    get_global 0
+    i32.const 1
+    i32.sub
+    set_global 0)
+  (func (;4;) (type 1)
+    get_global 0
+    i32.const 1
+    i32.add
+    set_global 0
+    get_global 0
+    i32.const 1024
+    i32.gt_u
+    if  ;; label = @1
+      unreachable
+    end
+    call 1
+    get_global 0
+    i32.const 1
+    i32.sub
+    set_global 0)
+  (global (;0;) (mut i32) (i32.const 0))
+  (export "exported_start" (func 4))
+  (export "call" (func 2))
+  (start 4))

tests/expectations/stack-height/table.wat

@@ -2,9 +2,6 @@
   (type (;0;) (func))
   (type (;1;) (func (param i32)))
   (type (;2;) (func (param i32 i32) (result i32)))
-  (type (;3;) (func (param i32 i32) (result i32)))
-  (type (;4;) (func (param i32)))
-  (type (;5;) (func (param i32 i32) (result i32)))
   (import "env" "foo" (func (;0;) (type 0)))
   (func (;1;) (type 1) (param i32)
     get_local 0
@@ -29,7 +26,7 @@
     get_local 0
     get_local 1
     i32.add)
-  (func (;3;) (type 3) (param i32 i32) (result i32)
+  (func (;3;) (type 2) (param i32 i32) (result i32)
     get_local 0
     get_local 1
     get_global 0
@@ -47,7 +44,7 @@
     i32.const 2
     i32.sub
     set_global 0)
-  (func (;4;) (type 4) (param i32)
+  (func (;4;) (type 1) (param i32)
     get_local 0
     get_global 0
     i32.const 2
@@ -64,7 +61,7 @@
     i32.const 2
     i32.sub
     set_global 0)
-  (func (;5;) (type 5) (param i32 i32) (result i32)
+  (func (;5;) (type 2) (param i32 i32) (result i32)
     get_local 0
     get_local 1
     get_global 0

tests/fixtures/gas/simple.wat

@@ -0,0 +1,15 @@
+(module
+	(func (export "simple")
+		(if (i32.const 1)
+			(loop
+				i32.const 123
+				drop
+			)
+		)
+	)
+
+	(func
+		block
+		end
+	)
+)

tests/fixtures/gas/start.wat

@@ -0,0 +1,18 @@
+(module
+	(import "env" "ext_return" (func $ext_return (param i32 i32)))
+	(import "env" "memory" (memory 1 1))
+
+	(start $start)
+	(func $start
+		(call $ext_return
+			(i32.const 8)
+			(i32.const 4)
+		)
+		(unreachable)
+	)
+
+	(func (export "call")
+	)
+
+	(data (i32.const 8) "\01\02\03\04")
+)

tests/fixtures/stack-height/start.wat

@@ -0,0 +1,11 @@
+(module
+	(import "env" "ext_return" (func $ext_return (param i32 i32)))
+	(import "env" "memory" (memory 1 1))
+
+	(start $start)
+	(func $start (export "exported_start")
+		(local i32)
+	)
+	(func (export "call")
+	)
+)