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