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/// 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_legacy_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 }))
}
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