Refactor Luau codegen to use wasmparser

codegen/luau/Cargo.toml

@@ -3,12 +3,11 @@ name = "codegen-luau"
 version = "0.6.0"
 edition = "2021"
 
+[dependencies]
+wasmparser = "0.86.0"
+
 [dependencies.wasm-ast]
 path = "../../wasm-ast"
 
-[dependencies.parity-wasm]
-git = "https://github.com/paritytech/parity-wasm.git"
-features = ["multi_value", "sign_ext"]
-
 [[bin]]
 name = "wasm2luau"

codegen/luau/src/analyzer/localize.rs

@@ -1,10 +1,10 @@
 use std::collections::BTreeSet;
 
-use parity_wasm::elements::ValueType;
 use wasm_ast::{
 	node::{BinOp, CmpOp, FuncData, LoadAt, MemoryGrow, MemorySize, StoreAt, UnOp, Value},
 	visit::{Driver, Visitor},
 };
+use wasmparser::ValType;
 
 use super::as_symbol::AsSymbol;
 
@@ -80,11 +80,7 @@ pub fn visit(ast: &FuncData) -> (BTreeSet<(&'static str, &'static str)>, BTreeSe
 		memory_set: BTreeSet::new(),
 	};
 
-	if ast
+	if ast.local_data().iter().any(|v| v.1 == ValType::I64) {
-		.local_data()
-		.iter()
-		.any(|v| v.value_type() == ValueType::I64)
-	{
 		visit.local_set.insert(("i64", "K_ZERO"));
 	}
 

codegen/luau/src/backend/statement.rs

@@ -3,11 +3,11 @@ use std::{
 	ops::Range,
 };
 
-use parity_wasm::elements::ValueType;
 use wasm_ast::node::{
 	Backward, Br, BrIf, BrTable, Call, CallIndirect, Forward, FuncData, If, MemoryGrow, SetGlobal,
 	SetLocal, SetTemporary, Statement, StoreAt, Terminator,
 };
+use wasmparser::ValType;
 
 use crate::analyzer::br_table;
 
@@ -327,9 +327,9 @@ fn write_parameter_list(ast: &FuncData, w: &mut dyn Write) -> Result<()> {
 fn write_variable_list(ast: &FuncData, w: &mut dyn Write) -> Result<()> {
 	let mut total = 0;
 
-	for data in ast.local_data().iter().filter(|v| v.count() != 0) {
+	for data in ast.local_data().iter().filter(|v| v.0 != 0) {
-		let range = total..total + usize::try_from(data.count()).unwrap();
+		let range = total..total + usize::try_from(data.0).unwrap();
-		let zero = if data.value_type() == ValueType::I64 {
+		let zero = if data.1 == ValType::I64 {
 			"i64_K_ZERO "
 		} else {
 			"0 "

codegen/luau/src/bin/wasm2luau.rs

@@ -1,12 +1,11 @@
 use std::io::{Result, Write};
 
-use parity_wasm::{deserialize_file, elements::Module};
+use wasm_ast::module::Module;
 
-fn load_module(name: &str) -> Module {
+fn load_arg_source() -> Result<Vec<u8>> {
-	deserialize_file(name)
+	let name = std::env::args().nth(1).expect("usage: wasm2luajit <file>");
-		.expect("Failed to parse WebAssembly file")
+
-		.parse_names()
+	std::fs::read(name)
-		.unwrap_or_else(|v| v.1)
 }
 
 fn do_runtime(lock: &mut dyn Write) -> Result<()> {
@@ -22,14 +21,8 @@ fn do_runtime(lock: &mut dyn Write) -> Result<()> {
 }
 
 fn main() -> Result<()> {
-	let wasm = match std::env::args().nth(1) {
+	let data = load_arg_source()?;
-		Some(name) => load_module(&name),
+	let wasm = Module::from_data(&data);
-		None => {
-			eprintln!("usage: wasm2luau <file>");
-
-			return Ok(());
-		}
-	};
 
 	let lock = &mut std::io::stdout().lock();
 

codegen/luau/src/translator.rs

@@ -3,42 +3,41 @@ use std::{
 	io::{Result, Write},
 };
 
-use parity_wasm::elements::{
-	External, ImportCountType, Instruction, Internal, Module, NameSection, ResizableLimits,
-};
-
 use wasm_ast::{
-	builder::{Builder, TypeInfo},
+	factory::Factory,
+	module::{External, Module, TypeInfo},
 	node::{FuncData, Statement},
 };
+use wasmparser::{
+	Data, DataKind, Element, ElementItem, ElementKind, Export, FunctionBody, Import, InitExpr,
+	Operator, OperatorsReader,
+};
 
 use crate::{
 	analyzer::localize,
 	backend::manager::{Driver, Manager},
 };
 
-fn to_internal_index(internal: Internal) -> u32 {
+trait AsIEName {
-	match internal {
+	fn as_ie_name(&self) -> &str;
-		Internal::Function(v) | Internal::Table(v) | Internal::Memory(v) | Internal::Global(v) => v,
+}
+
+impl AsIEName for External {
+	fn as_ie_name(&self) -> &str {
+		match self {
+			External::Func => "func_list",
+			External::Table => "table_list",
+			External::Memory => "memory_list",
+			External::Global => "global_list",
+			External::Tag => unimplemented!(),
+		}
 	}
 }
 
-fn limit_data_of(limits: &ResizableLimits) -> (u32, u32) {
+fn reader_to_code(reader: OperatorsReader) -> Vec<Operator> {
-	let max = limits.maximum().unwrap_or(0xFFFF);
+	let parsed: std::result::Result<_, _> = reader.into_iter().collect();
 
-	(limits.initial(), max)
+	parsed.unwrap()
-}
-
-fn write_table_init(limit: &ResizableLimits, w: &mut dyn Write) -> Result<()> {
-	let (a, b) = limit_data_of(limit);
-
-	write!(w, "{{ min = {a}, max = {b}, data = {{}} }}")
-}
-
-fn write_memory_init(limit: &ResizableLimits, w: &mut dyn Write) -> Result<()> {
-	let (a, b) = limit_data_of(limit);
-
-	write!(w, "rt.allocator.new({a}, {b})")
 }
 
 fn write_named_array(name: &str, len: usize, w: &mut dyn Write) -> Result<()> {
@@ -47,8 +46,9 @@ fn write_named_array(name: &str, len: usize, w: &mut dyn Write) -> Result<()> {
 	write!(w, "local {name} = table.create({len})")
 }
 
-fn write_constant(code: &[Instruction], type_info: &TypeInfo, w: &mut dyn Write) -> Result<()> {
+fn write_constant(init: &InitExpr, type_info: &TypeInfo, w: &mut dyn Write) -> Result<()> {
-	let func = Builder::from_type_info(type_info).build_anonymous(code);
+	let code = reader_to_code(init.get_operators_reader());
+	let func = Factory::from_type_info(type_info).create_anonymous(&code);
 
 	if let Some(Statement::SetTemporary(stat)) = func.code().code().last() {
 		stat.value().write(&mut Manager::default(), w)
@@ -57,128 +57,118 @@ fn write_constant(code: &[Instruction], type_info: &TypeInfo, w: &mut dyn Write)
 	}
 }
 
-fn write_import_of<T>(wasm: &Module, lower: &str, cond: T, w: &mut dyn Write) -> Result<()>
+fn write_import_of(list: &[Import], wanted: External, w: &mut dyn Write) -> Result<()> {
-where
+	let lower = wanted.as_ie_name();
-	T: Fn(&External) -> bool,
-{
-	let import = match wasm.import_section() {
-		Some(v) => v.entries(),
-		None => return Ok(()),
-	};
 	let upper = lower.to_uppercase();
 
-	for (i, v) in import.iter().filter(|v| cond(v.external())).enumerate() {
+	for (i, Import { name, module, .. }) in list
-		let field = v.field();
+		.iter()
-		let module = v.module();
+		.filter(|v| External::from(v.ty) == wanted)
-
+		.enumerate()
-		write!(w, r#"{upper}[{i}] = wasm["{module}"].{lower}["{field}"]"#)?;
+	{
+		write!(w, r#"{upper}[{i}] = wasm["{module}"].{lower}["{name}"]"#)?;
 	}
 
 	Ok(())
 }
 
-fn write_export_of<T>(wasm: &Module, lower: &str, cond: T, w: &mut dyn Write) -> Result<()>
+fn write_export_of(list: &[Export], wanted: External, w: &mut dyn Write) -> Result<()> {
-where
+	let lower = wanted.as_ie_name();
-	T: Fn(&Internal) -> bool,
-{
-	let export = match wasm.export_section() {
-		Some(v) => v.entries(),
-		None => return Ok(()),
-	};
 	let upper = lower.to_uppercase();
 
 	write!(w, "{lower} = {{")?;
 
-	for v in export.iter().filter(|v| cond(v.internal())) {
+	for Export { name, index, .. } in list.iter().filter(|v| External::from(v.kind) == wanted) {
-		let field = v.field();
+		write!(w, r#"["{name}"] = {upper}[{index}],"#)?;
-		let index = to_internal_index(*v.internal());
-
-		write!(w, r#"["{field}"] = {upper}[{index}],"#)?;
 	}
 
 	write!(w, "}},")
 }
 
-fn write_import_list(wasm: &Module, w: &mut dyn Write) -> Result<()> {
+fn write_import_list(list: &[Import], w: &mut dyn Write) -> Result<()> {
-	write_import_of(wasm, "func_list", |v| matches!(v, External::Function(_)), w)?;
+	write_import_of(list, External::Func, w)?;
-	write_import_of(wasm, "table_list", |v| matches!(v, External::Table(_)), w)?;
+	write_import_of(list, External::Table, w)?;
-	write_import_of(wasm, "memory_list", |v| matches!(v, External::Memory(_)), w)?;
+	write_import_of(list, External::Memory, w)?;
-	write_import_of(wasm, "global_list", |v| matches!(v, External::Global(_)), w)
+	write_import_of(list, External::Global, w)
 }
 
-fn write_export_list(wasm: &Module, w: &mut dyn Write) -> Result<()> {
+fn write_export_list(list: &[Export], w: &mut dyn Write) -> Result<()> {
-	write_export_of(wasm, "func_list", |v| matches!(v, Internal::Function(_)), w)?;
+	write_export_of(list, External::Func, w)?;
-	write_export_of(wasm, "table_list", |v| matches!(v, Internal::Table(_)), w)?;
+	write_export_of(list, External::Table, w)?;
-	write_export_of(wasm, "memory_list", |v| matches!(v, Internal::Memory(_)), w)?;
+	write_export_of(list, External::Memory, w)?;
-	write_export_of(wasm, "global_list", |v| matches!(v, Internal::Global(_)), w)
+	write_export_of(list, External::Global, w)
 }
 
 fn write_table_list(wasm: &Module, w: &mut dyn Write) -> Result<()> {
-	let table = match wasm.table_section() {
+	let offset = wasm.import_count(External::Table);
-		Some(v) => v.entries(),
+	let table = wasm.table_section();
-		None => return Ok(()),
-	};
-	let offset = wasm.import_count(ImportCountType::Table);
 
-	for (i, v) in table.iter().enumerate() {
+	for (i, table) in table.iter().enumerate() {
-		write!(w, "TABLE_LIST[{}] =", i + offset)?;
+		let index = offset + i;
-		write_table_init(v.limits(), w)?;
+		let min = table.initial;
+		let max = table.maximum.unwrap_or(0xFFFF);
+
+		write!(
+			w,
+			"TABLE_LIST[{index}] = {{ min = {min}, max = {max}, data = {{}} }}"
+		)?;
 	}
 
 	Ok(())
 }
 
 fn write_memory_list(wasm: &Module, w: &mut dyn Write) -> Result<()> {
-	let memory = match wasm.memory_section() {
+	let offset = wasm.import_count(External::Memory);
-		Some(v) => v.entries(),
+	let memory = wasm.memory_section();
-		None => return Ok(()),
-	};
-	let offset = wasm.import_count(ImportCountType::Memory);
 
 	for (i, v) in memory.iter().enumerate() {
-		write!(w, "MEMORY_LIST[{}] =", i + offset)?;
+		let index = offset + i;
-		write_memory_init(v.limits(), w)?;
+		let min = v.initial;
+		let max = v.maximum.unwrap_or(0xFFFF);
+
+		write!(w, "MEMORY_LIST[{index}] = rt.allocator.new({min}, {max})")?;
 	}
 
 	Ok(())
 }
 
 fn write_global_list(wasm: &Module, type_info: &TypeInfo, w: &mut dyn Write) -> Result<()> {
-	let global = match wasm.global_section() {
+	let offset = wasm.import_count(External::Global);
-		Some(v) => v,
+	let global = wasm.global_section();
-		None => return Ok(()),
-	};
-	let offset = wasm.import_count(ImportCountType::Global);
 
-	for (i, v) in global.entries().iter().enumerate() {
+	for (i, v) in global.iter().enumerate() {
 		write!(w, "GLOBAL_LIST[{}] = {{ value =", i + offset)?;
-		write_constant(v.init_expr().code(), type_info, w)?;
+		write_constant(&v.init_expr, type_info, w)?;
 		write!(w, "}}")?;
 	}
 
 	Ok(())
 }
 
-fn write_element_list(wasm: &Module, type_info: &TypeInfo, w: &mut dyn Write) -> Result<()> {
+fn write_element_list(list: &[Element], type_info: &TypeInfo, w: &mut dyn Write) -> Result<()> {
-	let element = match wasm.elements_section() {
+	for v in list {
-		Some(v) => v.entries(),
+		let (index, init) = match v.kind {
-		None => return Ok(()),
+			ElementKind::Active {
+				table_index,
+				init_expr,
+			} => (table_index, init_expr),
+			_ => unimplemented!(),
 		};
 
-	for v in element {
-		let code = v.offset().as_ref().unwrap().code();
-
 		write!(w, "do ")?;
-		write!(w, "local target = TABLE_LIST[{}].data ", v.index())?;
+		write!(w, "local target = TABLE_LIST[{index}].data ")?;
 		write!(w, "local offset =")?;
 
-		write_constant(code, type_info, w)?;
+		write_constant(&init, type_info, w)?;
 
 		write!(w, "local data = {{")?;
 
-		v.members()
+		for item in v.items.get_items_reader().unwrap() {
-			.iter()
+			match item.unwrap() {
-			.try_for_each(|v| write!(w, "FUNC_LIST[{v}],"))?;
+				ElementItem::Func(index) => write!(w, "FUNC_LIST[{index}],"),
+				ElementItem::Expr(init) => write_constant(&init, type_info, w),
+			}?;
+		}
 
 		write!(w, "}}")?;
 
@@ -190,36 +180,31 @@ fn write_element_list(wasm: &Module, type_info: &TypeInfo, w: &mut dyn Write) ->
 	Ok(())
 }
 
-fn write_data_list(wasm: &Module, type_info: &TypeInfo, w: &mut dyn Write) -> Result<()> {
+fn write_data_list(list: &[Data], type_info: &TypeInfo, w: &mut dyn Write) -> Result<()> {
-	let data = match wasm.data_section() {
+	for data in list {
-		Some(v) => v.entries(),
+		let (index, init) = match data.kind {
-		None => return Ok(()),
+			DataKind::Passive => unimplemented!(),
+			DataKind::Active {
+				memory_index,
+				init_expr,
+			} => (memory_index, init_expr),
 		};
 
-	for v in data {
-		let code = v.offset().as_ref().unwrap().code();
-		let index = v.index();
-
 		write!(w, "rt.store.string(")?;
 		write!(w, "MEMORY_LIST[{index}],")?;
-		write_constant(code, type_info, w)?;
+		write_constant(&init, type_info, w)?;
-		write!(w, r#","{}")"#, v.value().escape_ascii())?;
+		write!(w, r#","{}")"#, data.data.escape_ascii())?;
 	}
 
 	Ok(())
 }
 
-fn build_func_list(wasm: &Module, type_info: &TypeInfo) -> Vec<FuncData> {
+fn build_func_list(list: &[FunctionBody], type_info: &TypeInfo) -> Vec<FuncData> {
-	let list = match wasm.code_section() {
+	let mut builder = Factory::from_type_info(type_info);
-		Some(v) => v.bodies(),
-		None => return Vec::new(),
-	};
-
-	let mut builder = Builder::from_type_info(type_info);
 
 	list.iter()
 		.enumerate()
-		.map(|f| builder.build_indexed(f.0, f.1))
+		.map(|f| builder.create_indexed(f.0, f.1))
 		.collect()
 }
 
@@ -256,28 +241,20 @@ fn write_localize_used(func_list: &[FuncData], w: &mut dyn Write) -> Result<BTre
 }
 
 fn write_func_start(wasm: &Module, index: u32, w: &mut dyn Write) -> Result<()> {
-	let opt = wasm
-		.names_section()
-		.and_then(NameSection::functions)
-		.and_then(|v| v.names().get(index));
-
 	write!(w, "FUNC_LIST")?;
 
-	if let Some(name) = opt {
+	if let Some(name) = wasm.name_section().get(&index) {
 		write!(w, "--[[ {name} ]]")?;
 	}
 
 	write!(w, "[{index}] =")
 }
 
-fn write_func_list(
+fn write_func_list(wasm: &Module, func_list: &[FuncData], w: &mut dyn Write) -> Result<()> {
-	wasm: &Module,
+	let offset = wasm.import_count(External::Func);
-	type_info: &TypeInfo,
+
-	func_list: &[FuncData],
-	w: &mut dyn Write,
-) -> Result<()> {
 	func_list.iter().enumerate().try_for_each(|(i, v)| {
-		let index = (type_info.len_ex() + i).try_into().unwrap();
+		let index = (offset + i).try_into().unwrap();
 
 		write_func_start(wasm, index, w)?;
 
@@ -295,12 +272,12 @@ fn write_module_start(
 	write_table_list(wasm, w)?;
 	write_memory_list(wasm, w)?;
 	write_global_list(wasm, type_info, w)?;
-	write_element_list(wasm, type_info, w)?;
+	write_element_list(wasm.element_section(), type_info, w)?;
-	write_data_list(wasm, type_info, w)?;
+	write_data_list(wasm.data_section(), type_info, w)?;
 	write!(w, "end ")?;
 
 	write!(w, "return function(wasm)")?;
-	write_import_list(wasm, w)?;
+	write_import_list(wasm.import_section(), w)?;
 	write!(w, "run_init_code()")?;
 
 	for mem in mem_set {
@@ -312,30 +289,30 @@ fn write_module_start(
 	}
 
 	write!(w, "return {{")?;
-	write_export_list(wasm, w)?;
+	write_export_list(wasm.export_section(), w)?;
 	write!(w, "}} end ")
 }
 
 /// # Errors
 /// Returns `Err` if writing to `Write` failed.
-pub fn from_inst_list(code: &[Instruction], type_info: &TypeInfo, w: &mut dyn Write) -> Result<()> {
+pub fn from_inst_list(code: &[Operator], type_info: &TypeInfo, w: &mut dyn Write) -> Result<()> {
-	Builder::from_type_info(type_info)
+	Factory::from_type_info(type_info)
-		.build_anonymous(code)
+		.create_anonymous(code)
 		.write(&mut Manager::default(), w)
 }
 
 /// # Errors
 /// Returns `Err` if writing to `Write` failed.
 pub fn from_module_typed(wasm: &Module, type_info: &TypeInfo, w: &mut dyn Write) -> Result<()> {
-	let func_list = build_func_list(wasm, type_info);
+	let func_list = build_func_list(wasm.code_section(), type_info);
 	let mem_set = write_localize_used(&func_list, w)?;
 
-	write_named_array("FUNC_LIST", wasm.functions_space(), w)?;
+	write_named_array("FUNC_LIST", wasm.function_space(), w)?;
 	write_named_array("TABLE_LIST", wasm.table_space(), w)?;
 	write_named_array("MEMORY_LIST", wasm.memory_space(), w)?;
-	write_named_array("GLOBAL_LIST", wasm.globals_space(), w)?;
+	write_named_array("GLOBAL_LIST", wasm.global_space(), w)?;
 
-	write_func_list(wasm, type_info, &func_list, w)?;
+	write_func_list(wasm, &func_list, w)?;
 	write_module_start(wasm, type_info, &mem_set, w)
 }
 

dev-test/fuzz_targets/luau_translate.rs

@@ -1,16 +1,14 @@
 #![no_main]
 
-use wasm_smith::Module;
+use wasm_ast::module::Module;
+use wasm_smith::Module as RngModule;
 
 // We are not interested in parity_wasm errors.
-libfuzzer_sys::fuzz_target!(|module: Module| {
+libfuzzer_sys::fuzz_target!(|module: RngModule| {
 	let data = module.to_bytes();
-	let wasm = match parity_wasm::deserialize_buffer(&data) {
+	let wasm = Module::from_data(&data);
-		Ok(v) => v,
-		Err(_) => return,
-	};
 
 	let sink = &mut std::io::sink();
 
-	codegen_luau::from_module_untyped(&wasm, sink).expect("Luau should succeed");
+	codegen_luau::from_module_untyped(&wasm, sink).expect("LuaJIT should succeed");
 });

dev-test/tests/luau_translate.rs

@@ -3,8 +3,7 @@ use std::{
 	path::PathBuf,
 };
 
-use parity_wasm::elements::Module;
+use wasm_ast::module::{Module, TypeInfo};
-use wasm_ast::builder::TypeInfo;
 use wast::{
 	core::{Expression, Instruction},
 	AssertExpression, WastExecute, WastInvoke,