Remove unneeded Luau branch gadgets

Fixiee

codegen/luau/src/analyzer/br_table.rs

@@ -1,29 +0,0 @@
-use std::collections::HashMap;
-
-use wasm_ast::{
-	node::{BrTable, FuncData},
-	visit::{Driver, Visitor},
-};
-
-struct Visit {
-	id_map: HashMap<usize, usize>,
-}
-
-impl Visitor for Visit {
-	fn visit_br_table(&mut self, table: &BrTable) {
-		let id = table as *const _ as usize;
-		let len = self.id_map.len() + 1;
-
-		self.id_map.insert(id, len);
-	}
-}
-
-pub fn visit(ast: &FuncData) -> HashMap<usize, usize> {
-	let mut visit = Visit {
-		id_map: HashMap::new(),
-	};
-
-	ast.accept(&mut visit);
-
-	visit.id_map
-}

codegen/luau/src/analyzer/br_target.rs

@@ -0,0 +1,40 @@
+use std::collections::HashMap;
+
+use wasm_ast::{
+	node::{Br, BrIf, BrTable, FuncData},
+	visit::{Driver, Visitor},
+};
+
+struct Visit {
+	br_map: HashMap<usize, usize>,
+	has_branch: bool,
+}
+
+impl Visitor for Visit {
+	fn visit_br(&mut self, _: &Br) {
+		self.has_branch = true;
+	}
+
+	fn visit_br_if(&mut self, _: &BrIf) {
+		self.has_branch = true;
+	}
+
+	fn visit_br_table(&mut self, table: &BrTable) {
+		let id = table as *const _ as usize;
+		let len = self.br_map.len() + 1;
+
+		self.has_branch = true;
+		self.br_map.insert(id, len);
+	}
+}
+
+pub fn visit(ast: &FuncData) -> (HashMap<usize, usize>, bool) {
+	let mut visit = Visit {
+		br_map: HashMap::new(),
+		has_branch: false,
+	};
+
+	ast.accept(&mut visit);
+
+	(visit.br_map, visit.has_branch)
+}

codegen/luau/src/analyzer/mod.rs

@@ -1,3 +1,3 @@
 pub mod as_symbol;
-pub mod br_table;
+pub mod br_target;
 pub mod localize;

codegen/luau/src/backend/statement.rs

@@ -9,7 +9,7 @@ use wasm_ast::node::{
 };
 use wasmparser::ValType;
 
-use crate::analyzer::br_table;
+use crate::analyzer::br_target;
 
 use super::manager::{
 	write_ascending, write_condition, write_separated, write_variable, Driver, Manager,
@@ -130,7 +130,7 @@ fn write_br_gadget(
 	label: usize,
 	w: &mut dyn Write,
 ) -> Result<()> {
-	if label_list.len() == 1 {
+	if label_list.len() == 1 || label_list.iter().all(Option::is_none) {
 		return Ok(());
 	}
 
@@ -340,17 +340,20 @@ fn write_variable_list(ast: &FuncData, w: &mut dyn Write) -> Result<()> {
 
 impl Driver for FuncData {
 	fn write(&self, mng: &mut Manager, w: &mut dyn Write) -> Result<()> {
-		let br_map = br_table::visit(self);
+		let br_data = br_target::visit(self);
 
 		write_parameter_list(self, w)?;
 		write_variable_list(self, w)?;
-		write!(w, "local desired ")?;
 
-		if !br_map.is_empty() {
+		if br_data.1 {
+			write!(w, "local desired ")?;
+		}
+
+		if !br_data.0.is_empty() {
 			write!(w, "local br_map = {{}} ")?;
 		}
 
-		mng.set_table_map(br_map);
+		mng.set_table_map(br_data.0);
 		mng.set_num_param(self.num_param());
 		self.code().write(mng, w)?;