86 lines
4.4 KiB
Rust
86 lines
4.4 KiB
Rust
extern crate parity_wasm;
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extern crate wasmi;
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use std::env::args;
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use parity_wasm::elements::{Internal, External, Type, FunctionType, ValueType};
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use wasmi::{RuntimeValue, ModuleInstance, NopExternals, ImportsBuilder};
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fn main() {
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let args: Vec<_> = args().collect();
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if args.len() < 3 {
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println!("Usage: {} <wasm file> <exported func> [<arg>...]", args[0]);
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return;
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}
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let func_name = &args[2];
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let (_, program_args) = args.split_at(3);
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let module = parity_wasm::deserialize_file(&args[1]).expect("File to be deserialized");
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// Extracts call arguments from command-line arguments
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let args = {
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// Export section has an entry with a func_name with an index inside a module
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let export_section = module.export_section().expect("No export section found");
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// It's a section with function declarations (which are references to the type section entries)
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let function_section = module.function_section().expect("No function section found");
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// Type section stores function types which are referenced by function_section entries
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let type_section = module.type_section().expect("No type section found");
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// Given function name used to find export section entry which contains
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// an `internal` field which points to the index in the function index space
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let found_entry = export_section.entries().iter()
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.find(|entry| func_name == entry.field()).expect(&format!("No export with name {} found", func_name));
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// Function index in the function index space (internally-defined + imported)
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let function_index: usize = match found_entry.internal() {
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&Internal::Function(index) => index as usize,
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_ => panic!("Founded export is not a function"),
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};
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// We need to count import section entries (functions only!) to subtract it from function_index
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// and obtain the index within the function section
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let import_section_len: usize = match module.import_section() {
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Some(import) =>
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import.entries().iter().filter(|entry| match entry.external() {
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&External::Function(_) => true,
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_ => false,
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}).count(),
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None => 0,
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};
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// Calculates a function index within module's function section
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let function_index_in_section = function_index - import_section_len;
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// Getting a type reference from a function section entry
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let func_type_ref: usize = function_section.entries()[function_index_in_section].type_ref() as usize;
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// Use the reference to get an actual function type
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let function_type: &FunctionType = match &type_section.types()[func_type_ref] {
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&Type::Function(ref func_type) => func_type,
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};
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// Parses arguments and constructs runtime values in correspondence of their types
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function_type.params().iter().enumerate().map(|(i, value)| match value {
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&ValueType::I32 => RuntimeValue::I32(program_args[i].parse::<i32>().expect(&format!("Can't parse arg #{} as i32", program_args[i]))),
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&ValueType::I64 => RuntimeValue::I64(program_args[i].parse::<i64>().expect(&format!("Can't parse arg #{} as i64", program_args[i]))),
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&ValueType::F32 => RuntimeValue::F32(program_args[i].parse::<f32>().expect(&format!("Can't parse arg #{} as f32", program_args[i]))),
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&ValueType::F64 => RuntimeValue::F64(program_args[i].parse::<f64>().expect(&format!("Can't parse arg #{} as f64", program_args[i]))),
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}).collect::<Vec<RuntimeValue>>()
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};
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let loaded_module = wasmi::Module::from_module(module).expect("Module to be valid");
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// Intialize deserialized module. It adds module into It expects 3 parameters:
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// - a name for the module
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// - a module declaration
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// - "main" module doesn't import native module(s) this is why we don't need to provide external native modules here
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// This test shows how to implement native module https://github.com/NikVolf/parity-wasm/blob/master/src/interpreter/tests/basics.rs#L197
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let main = ModuleInstance::new(&loaded_module, &ImportsBuilder::default())
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.expect("Failed to instantiate module")
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.run_start(&mut NopExternals)
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.expect("Failed to run start function in module");
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println!("Result: {:?}", main.invoke_export(func_name, &args, &mut NopExternals).expect(""));
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}
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