wasm-pack utility to pack wasm files into transactions payload

Cargo.toml

@@ -22,4 +22,8 @@ path = "ext/src/main.rs"
 
 [[bin]]
 name = "wasm-gas"
-path = "gas/src/main.rs"
+path = "gas/src/main.rs"
+
+[[bin]]
+name = "wasm-pack"
+path = "pack/src/main.rs"

pack/.gitignore

@@ -0,0 +1,2 @@
+target
+Cargo.lock

pack/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "wasm-pack"
+version = "0.1.0"
+authors = ["NikVolf <nikvolf@gmail.com>"]
+
+[dependencies]
+parity-wasm = { git="https://github.com/nikvolf/parity-wasm" }
+wasm-utils = { path = "../" }
+clap = "2.24"

pack/src/main.rs

@@ -0,0 +1,32 @@
+extern crate parity_wasm;
+extern crate wasm_utils;
+extern crate clap;
+
+use clap::{App, Arg};
+
+fn main() {
+    wasm_utils::init_log();
+
+    let matches = App::new("wasm-opt")
+                        .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");
+
+    // doing serialization roundtrip to make sure the input is a valid wasm module
+    let module = parity_wasm::deserialize_file(&input).expect("Failed to load wasm module from file");
+    let bytes = parity_wasm::serialize(module).expect("Failed to serialize wasm module");
+
+    // Wrap contract code into the wasm module that returns it
+    let packed_module = wasm_utils::pack_instance(bytes);
+
+    parity_wasm::serialize_to_file(&output, packed_module).unwrap();
+}

src/gas.rs

@@ -1,6 +1,5 @@
 use parity_wasm::{elements, builder};
 
-
 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() {

src/lib.rs

@@ -8,8 +8,10 @@ mod gas;
 mod symbols;
 mod logger;
 mod ext;
+mod pack;
 
 pub use optimizer::{optimize, Error as OptimizerError};
 pub use gas::inject_gas_counter;
 pub use logger::init_log;
-pub use ext::externalize;
+pub use ext::externalize;
+pub use pack::pack_instance;

src/pack.rs

@@ -0,0 +1,35 @@
+use parity_wasm::{elements, builder};
+
+pub fn pack_instance(raw_module: Vec<u8>) -> elements::Module {
+
+    let raw_len = raw_module.len();
+    let mem_required = (raw_len / (64 * 1024) + 1) as u32;
+
+    let module = builder::module()
+        .import()
+            .module("env")
+            .field("memory")
+            .external()
+            .memory(mem_required as u32, Some(mem_required as u32))
+            .build()
+        .data()
+            .offset(elements::Opcode::I32Const(0))
+            .value(raw_module)
+            .build()
+        .function()
+            .signature().param().i32().build()
+            .body().with_opcodes(elements::Opcodes::new(vec![
+                elements::Opcode::GetLocal(0),
+                elements::Opcode::I32Const(raw_len as i32),
+                elements::Opcode::I32Store(0, 12),
+                elements::Opcode::End,
+            ])).build()
+            .build()
+        .export()
+            .field("_call")
+            .internal().func(0)
+            .build()
+        .build();
+
+    module
+}