Method parse_external_name

cranelift/reader/src/parser.rs:1319–1374

Parse an external name. For example, in a function reference decl, the parser would be in this state: fn0 = * name signature

(&mut self)

    // fn0 = * name signature
    //
    fn parse_external_name(&mut self) -> ParseResult<ExternalName> {
        match self.token() {
            Some(Token::Name(s)) => {
                self.consume();
                s.parse()
                    .map_err(|_| self.error("invalid test case or libcall name"))
            }

            Some(Token::UserNameRef(name_ref)) => {
                self.consume();
                Ok(ExternalName::user(UserExternalNameRef::new(
                    name_ref as usize,
                )))
            }

            Some(Token::UserRef(namespace)) => {
                self.consume();
                if let Some(Token::Colon) = self.token() {
                    self.consume();
                    match self.token() {
                        Some(Token::Integer(index_str)) => {
                            let index: u32 = u32::from_str_radix(index_str, 10).map_err(|_| {
                                self.error("the integer given overflows the u32 type")
                            })?;
                            self.consume();

                            // Deduplicate the reference (O(n), but should be fine for tests),
                            // to follow `FunctionParameters::declare_imported_user_function`,
                            // otherwise this will cause ref mismatches when asserted below.
                            let name_ref = self
                                .predeclared_external_names
                                .iter()
                                .find_map(|(reff, name)| {
                                    if name.index == index && name.namespace == namespace {
                                        Some(reff)
                                    } else {
                                        None
                                    }
                                })
                                .unwrap_or_else(|| {
                                    self.predeclared_external_names
                                        .push(ir::UserExternalName { namespace, index })
                                });

                            Ok(ExternalName::user(name_ref))
                        }
                        _ => err!(self.loc, "expected integer"),
                    }
                } else {
                    err!(self.loc, "expected colon")
                }
            }

            _ => err!(self.loc, "expected external name"),
        }
    }

    // Parse a function signature.