Commit `6fcd72355c`

Luuk de Gram <luuk@degram.dev>

2022-10-15 18:56:58

wasm: correctly get the type of a local for free

When determining the type of a local (read: register), we would previously subtract the stack locals also. However, this locals are also within the same `locals` list, meaning the type of the local we were retrieving was off by 2. This could create a validation error when we re-use a local of a different type.

master

1 parent e62bb1d

Changed files (1)

src

arch

wasm

CodeGen.zig

@@ -106,8 +106,8 @@ const WValue = union(enum) {
     fn free(value: *WValue, gen: *Self) void {
         if (value.* != .local) return;
         const local_value = value.local.value;
-        const reserved = gen.args.len + @boolToInt(gen.return_value != .none) + 2; // 2 for stack locals
-        if (local_value < reserved) return; // reserved locals may never be re-used.
+        const reserved = gen.args.len + @boolToInt(gen.return_value != .none);
+        if (local_value < reserved + 2) return; // reserved locals may never be re-used. Also accounts for 2 stack locals.
 
         const index = local_value - reserved;
         const valtype = @intToEnum(wasm.Valtype, gen.locals.items[index]);

Commit 6fcd72355c

Commit `6fcd72355c`