read/wasm: Ignore errors when loading name subsection (#408)

The version of `wasmparser` currently in use does not
support extended name sections and will return an error
when such an unknown subsection is encountered.
This commit is a quick work-around until `wasmparser`
is updated to the most recent version - which is a
rather big undertaking unfortunately.

One downside of this work-around is that ill-formed
name subsections (e.g. for function names) are
silently ignored.

src/read/wasm.rs

@@ -254,25 +254,30 @@ impl<'data, R: ReadRef<'data>> WasmFile<'data, R> {
                         .get_name_section_reader()
                         .read_error("Couldn't read header of the name section")?
                     {
-                        let name =
-                            match name.read_error("Couldn't read header of a name subsection")? {
-                                wp::Name::Function(name) => name,
-                                _ => continue,
-                            };
-                        let mut name_map = name
-                            .get_map()
-                            .read_error("Couldn't read header of the function name subsection")?;
-                        for _ in 0..name_map.get_count() {
-                            let naming = name_map
-                                .read()
-                                .read_error("Couldn't read a function name")?;
-                            if let Some(local_index) =
-                                naming.index.checked_sub(imported_funcs_count)
-                            {
-                                if let LocalFunctionKind::Local { symbol_id } =
-                                    local_func_kinds[local_index as usize]
+                        // TODO: Right now, ill-formed name subsections
+                        // are silently ignored in order to maintain
+                        // compatibility with extended name sections, which
+                        // are not yet supported by the version of
+                        // `wasmparser` currently used.
+                        // A better fix would be to update `wasmparser` to
+                        // the newest version, but this requires
+                        // a major rewrite of this file.
+                        if let Ok(wp::Name::Function(name)) = name {
+                            let mut name_map = name.get_map().read_error(
+                                "Couldn't read header of the function name subsection",
+                            )?;
+                            for _ in 0..name_map.get_count() {
+                                let naming = name_map
+                                    .read()
+                                    .read_error("Couldn't read a function name")?;
+                                if let Some(local_index) =
+                                    naming.index.checked_sub(imported_funcs_count)
                                 {
-                                    file.symbols[symbol_id as usize].name = naming.name;
+                                    if let LocalFunctionKind::Local { symbol_id } =
+                                        local_func_kinds[local_index as usize]
+                                    {
+                                        file.symbols[symbol_id as usize].name = naming.name;
+                                    }
                                 }
                             }
                         }