| /// Module-level assembly support. |
| /// |
| /// The macro defined here allows you to specify "top-level", |
| /// "file-scoped", or "module-level" assembly. These synonyms |
| /// all correspond to LLVM's module-level inline assembly instruction. |
| /// |
| /// For example, `global_asm!("some assembly here")` codegens to |
| /// LLVM's `module asm "some assembly here"`. All of LLVM's caveats |
| /// therefore apply. |
| |
| use errors::DiagnosticBuilder; |
| |
| use syntax::ast; |
| use syntax::source_map::respan; |
| use syntax::ext::base::{self, *}; |
| use syntax::parse::token; |
| use syntax::ptr::P; |
| use syntax_pos::Span; |
| use syntax::tokenstream::TokenStream; |
| use smallvec::smallvec; |
| |
| pub fn expand_global_asm<'cx>(cx: &'cx mut ExtCtxt<'_>, |
| sp: Span, |
| tts: TokenStream) -> Box<dyn base::MacResult + 'cx> { |
| match parse_global_asm(cx, sp, tts) { |
| Ok(Some(global_asm)) => { |
| MacEager::items(smallvec![P(ast::Item { |
| ident: ast::Ident::invalid(), |
| attrs: Vec::new(), |
| id: ast::DUMMY_NODE_ID, |
| node: ast::ItemKind::GlobalAsm(P(global_asm)), |
| vis: respan(sp.shrink_to_lo(), ast::VisibilityKind::Inherited), |
| span: cx.with_def_site_ctxt(sp), |
| tokens: None, |
| })]) |
| } |
| Ok(None) => DummyResult::any(sp), |
| Err(mut err) => { |
| err.emit(); |
| DummyResult::any(sp) |
| } |
| } |
| } |
| |
| fn parse_global_asm<'a>( |
| cx: &mut ExtCtxt<'a>, |
| sp: Span, |
| tts: TokenStream |
| ) -> Result<Option<ast::GlobalAsm>, DiagnosticBuilder<'a>> { |
| let mut p = cx.new_parser_from_tts(tts); |
| |
| if p.token == token::Eof { |
| let mut err = cx.struct_span_err(sp, "macro requires a string literal as an argument"); |
| err.span_label(sp, "string literal required"); |
| return Err(err); |
| } |
| |
| let expr = p.parse_expr()?; |
| let (asm, _) = match expr_to_string(cx, expr, "inline assembly must be a string literal") { |
| Some((s, st)) => (s, st), |
| None => return Ok(None), |
| }; |
| |
| Ok(Some(ast::GlobalAsm { asm })) |
| } |