4 use rustc_ast::tokenstream::TokenStream;
5 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
6 use rustc_errors::{Applicability, DiagnosticBuilder};
7 use rustc_expand::base::{self, *};
8 use rustc_parse::parser::Parser;
9 use rustc_parse_format as parse;
10 use rustc_session::lint;
11 use rustc_span::symbol::Ident;
12 use rustc_span::symbol::{kw, sym, Symbol};
13 use rustc_span::{InnerSpan, Span};
14 use rustc_target::asm::InlineAsmArch;
15 use smallvec::smallvec;
18 templates: Vec<P<ast::Expr>>,
19 operands: Vec<(ast::InlineAsmOperand, Span)>,
20 named_args: FxHashMap<Symbol, usize>,
21 reg_args: FxHashSet<usize>,
22 clobber_abi: Option<(Symbol, Span)>,
23 options: ast::InlineAsmOptions,
24 options_spans: Vec<Span>,
28 ecx: &mut ExtCtxt<'a>,
32 ) -> Result<AsmArgs, DiagnosticBuilder<'a>> {
33 let mut p = ecx.new_parser_from_tts(tts);
35 if p.token == token::Eof {
36 return Err(ecx.struct_span_err(sp, "requires at least a template string argument"));
39 // Detect use of the legacy llvm_asm! syntax (which used to be called asm!)
40 if !is_global_asm && p.look_ahead(1, |t| *t == token::Colon || *t == token::ModSep) {
42 ecx.struct_span_err(sp, "the legacy LLVM-style asm! syntax is no longer supported");
43 err.note("consider migrating to the new asm! syntax specified in RFC 2873");
44 err.note("alternatively, switch to llvm_asm! to keep your code working as it is");
46 // Find the span of the "asm!" so that we can offer an automatic suggestion
47 let asm_span = sp.from_inner(InnerSpan::new(0, 4));
48 if let Ok(s) = ecx.source_map().span_to_snippet(asm_span) {
54 Applicability::MachineApplicable,
61 let first_template = p.parse_expr()?;
62 let mut args = AsmArgs {
63 templates: vec![first_template],
65 named_args: FxHashMap::default(),
66 reg_args: FxHashSet::default(),
68 options: ast::InlineAsmOptions::empty(),
69 options_spans: vec![],
72 let mut allow_templates = true;
73 while p.token != token::Eof {
74 if !p.eat(&token::Comma) {
76 // After a template string, we always expect *only* a comma...
77 let mut err = ecx.struct_span_err(p.token.span, "expected token: `,`");
78 err.span_label(p.token.span, "expected `,`");
79 p.maybe_annotate_with_ascription(&mut err, false);
82 // ...after that delegate to `expect` to also include the other expected tokens.
83 return Err(p.expect(&token::Comma).err().unwrap());
86 if p.token == token::Eof {
88 } // accept trailing commas
91 if p.eat_keyword(sym::clobber_abi) {
92 parse_clobber_abi(&mut p, &mut args)?;
93 allow_templates = false;
98 if p.eat_keyword(sym::options) {
99 parse_options(&mut p, &mut args, is_global_asm)?;
100 allow_templates = false;
104 let span_start = p.token.span;
106 // Parse operand names
107 let name = if p.token.is_ident() && p.look_ahead(1, |t| *t == token::Eq) {
108 let (ident, _) = p.token.ident().unwrap();
110 p.expect(&token::Eq)?;
111 allow_templates = false;
117 let mut explicit_reg = false;
118 let op = if !is_global_asm && p.eat_keyword(kw::In) {
119 let reg = parse_reg(&mut p, &mut explicit_reg)?;
120 if p.eat_keyword(kw::Underscore) {
121 let err = ecx.struct_span_err(p.token.span, "_ cannot be used for input operands");
124 let expr = p.parse_expr()?;
125 ast::InlineAsmOperand::In { reg, expr }
126 } else if !is_global_asm && p.eat_keyword(sym::out) {
127 let reg = parse_reg(&mut p, &mut explicit_reg)?;
128 let expr = if p.eat_keyword(kw::Underscore) { None } else { Some(p.parse_expr()?) };
129 ast::InlineAsmOperand::Out { reg, expr, late: false }
130 } else if !is_global_asm && p.eat_keyword(sym::lateout) {
131 let reg = parse_reg(&mut p, &mut explicit_reg)?;
132 let expr = if p.eat_keyword(kw::Underscore) { None } else { Some(p.parse_expr()?) };
133 ast::InlineAsmOperand::Out { reg, expr, late: true }
134 } else if !is_global_asm && p.eat_keyword(sym::inout) {
135 let reg = parse_reg(&mut p, &mut explicit_reg)?;
136 if p.eat_keyword(kw::Underscore) {
137 let err = ecx.struct_span_err(p.token.span, "_ cannot be used for input operands");
140 let expr = p.parse_expr()?;
141 if p.eat(&token::FatArrow) {
143 if p.eat_keyword(kw::Underscore) { None } else { Some(p.parse_expr()?) };
144 ast::InlineAsmOperand::SplitInOut { reg, in_expr: expr, out_expr, late: false }
146 ast::InlineAsmOperand::InOut { reg, expr, late: false }
148 } else if !is_global_asm && p.eat_keyword(sym::inlateout) {
149 let reg = parse_reg(&mut p, &mut explicit_reg)?;
150 if p.eat_keyword(kw::Underscore) {
151 let err = ecx.struct_span_err(p.token.span, "_ cannot be used for input operands");
154 let expr = p.parse_expr()?;
155 if p.eat(&token::FatArrow) {
157 if p.eat_keyword(kw::Underscore) { None } else { Some(p.parse_expr()?) };
158 ast::InlineAsmOperand::SplitInOut { reg, in_expr: expr, out_expr, late: true }
160 ast::InlineAsmOperand::InOut { reg, expr, late: true }
162 } else if p.eat_keyword(kw::Const) {
163 let anon_const = p.parse_anon_const_expr()?;
164 ast::InlineAsmOperand::Const { anon_const }
165 } else if !is_global_asm && p.eat_keyword(sym::sym) {
166 let expr = p.parse_expr()?;
168 ast::ExprKind::Path(..) => {}
171 .struct_span_err(expr.span, "argument to `sym` must be a path expression");
175 ast::InlineAsmOperand::Sym { expr }
176 } else if allow_templates {
177 let template = p.parse_expr()?;
178 // If it can't possibly expand to a string, provide diagnostics here to include other
179 // things it could have been.
180 match template.kind {
181 ast::ExprKind::Lit(ast::Lit { kind: ast::LitKind::Str(..), .. }) => {}
182 ast::ExprKind::MacCall(..) => {}
184 let errstr = if is_global_asm {
185 "expected operand, options, or additional template string"
187 "expected operand, clobber_abi, options, or additional template string"
189 let mut err = ecx.struct_span_err(template.span, errstr);
190 err.span_label(template.span, errstr);
194 args.templates.push(template);
197 return p.unexpected();
200 allow_templates = false;
201 let span = span_start.to(p.prev_token.span);
202 let slot = args.operands.len();
203 args.operands.push((op, span));
205 // Validate the order of named, positional & explicit register operands and
206 // clobber_abi/options. We do this at the end once we have the full span
207 // of the argument available.
208 if !args.options_spans.is_empty() {
209 ecx.struct_span_err(span, "arguments are not allowed after options")
210 .span_labels(args.options_spans.clone(), "previous options")
211 .span_label(span, "argument")
213 } else if let Some((_, abi_span)) = args.clobber_abi {
214 ecx.struct_span_err(span, "arguments are not allowed after clobber_abi")
215 .span_label(abi_span, "clobber_abi")
216 .span_label(span, "argument")
221 ecx.struct_span_err(span, "explicit register arguments cannot have names").emit();
223 args.reg_args.insert(slot);
224 } else if let Some(name) = name {
225 if let Some(&prev) = args.named_args.get(&name) {
226 ecx.struct_span_err(span, &format!("duplicate argument named `{}`", name))
227 .span_label(args.operands[prev].1, "previously here")
228 .span_label(span, "duplicate argument")
232 if !args.reg_args.is_empty() {
233 let mut err = ecx.struct_span_err(
235 "named arguments cannot follow explicit register arguments",
237 err.span_label(span, "named argument");
238 for pos in &args.reg_args {
239 err.span_label(args.operands[*pos].1, "explicit register argument");
243 args.named_args.insert(name, slot);
245 if !args.named_args.is_empty() || !args.reg_args.is_empty() {
246 let mut err = ecx.struct_span_err(
248 "positional arguments cannot follow named arguments \
249 or explicit register arguments",
251 err.span_label(span, "positional argument");
252 for pos in args.named_args.values() {
253 err.span_label(args.operands[*pos].1, "named argument");
255 for pos in &args.reg_args {
256 err.span_label(args.operands[*pos].1, "explicit register argument");
263 if args.options.contains(ast::InlineAsmOptions::NOMEM)
264 && args.options.contains(ast::InlineAsmOptions::READONLY)
266 let spans = args.options_spans.clone();
267 ecx.struct_span_err(spans, "the `nomem` and `readonly` options are mutually exclusive")
270 if args.options.contains(ast::InlineAsmOptions::PURE)
271 && args.options.contains(ast::InlineAsmOptions::NORETURN)
273 let spans = args.options_spans.clone();
274 ecx.struct_span_err(spans, "the `pure` and `noreturn` options are mutually exclusive")
277 if args.options.contains(ast::InlineAsmOptions::PURE)
278 && !args.options.intersects(ast::InlineAsmOptions::NOMEM | ast::InlineAsmOptions::READONLY)
280 let spans = args.options_spans.clone();
283 "the `pure` option must be combined with either `nomem` or `readonly`",
288 let mut have_real_output = false;
289 let mut outputs_sp = vec![];
290 let mut regclass_outputs = vec![];
291 for (op, op_sp) in &args.operands {
293 ast::InlineAsmOperand::Out { reg, expr, .. }
294 | ast::InlineAsmOperand::SplitInOut { reg, out_expr: expr, .. } => {
295 outputs_sp.push(*op_sp);
296 have_real_output |= expr.is_some();
297 if let ast::InlineAsmRegOrRegClass::RegClass(_) = reg {
298 regclass_outputs.push(*op_sp);
301 ast::InlineAsmOperand::InOut { reg, .. } => {
302 outputs_sp.push(*op_sp);
303 have_real_output = true;
304 if let ast::InlineAsmRegOrRegClass::RegClass(_) = reg {
305 regclass_outputs.push(*op_sp);
311 if args.options.contains(ast::InlineAsmOptions::PURE) && !have_real_output {
313 args.options_spans.clone(),
314 "asm with the `pure` option must have at least one output",
318 if args.options.contains(ast::InlineAsmOptions::NORETURN) && !outputs_sp.is_empty() {
320 .struct_span_err(outputs_sp, "asm outputs are not allowed with the `noreturn` option");
322 // Bail out now since this is likely to confuse MIR
325 if let Some((_, abi_span)) = args.clobber_abi {
328 ecx.struct_span_err(abi_span, "`clobber_abi` cannot be used with `global_asm!`");
330 // Bail out now since this is likely to confuse later stages
333 if !regclass_outputs.is_empty() {
335 regclass_outputs.clone(),
336 "asm with `clobber_abi` must specify explicit registers for outputs",
338 .span_label(abi_span, "clobber_abi")
339 .span_labels(regclass_outputs, "generic outputs")
347 /// Report a duplicate option error.
349 /// This function must be called immediately after the option token is parsed.
350 /// Otherwise, the suggestion will be incorrect.
351 fn err_duplicate_option<'a>(p: &mut Parser<'a>, symbol: Symbol, span: Span) {
355 .struct_span_err(span, &format!("the `{}` option was already provided", symbol));
356 err.span_label(span, "this option was already provided");
359 let mut full_span = span;
360 if p.token.kind == token::Comma {
361 full_span = full_span.to(p.token.span);
363 err.tool_only_span_suggestion(
365 "remove this option",
367 Applicability::MachineApplicable,
373 /// Try to set the provided option in the provided `AsmArgs`.
374 /// If it is already set, report a duplicate option error.
376 /// This function must be called immediately after the option token is parsed.
377 /// Otherwise, the error will not point to the correct spot.
378 fn try_set_option<'a>(
382 option: ast::InlineAsmOptions,
384 if !args.options.contains(option) {
385 args.options |= option;
387 err_duplicate_option(p, symbol, p.prev_token.span);
391 fn parse_options<'a>(
395 ) -> Result<(), DiagnosticBuilder<'a>> {
396 let span_start = p.prev_token.span;
398 p.expect(&token::OpenDelim(token::DelimToken::Paren))?;
400 while !p.eat(&token::CloseDelim(token::DelimToken::Paren)) {
401 if !is_global_asm && p.eat_keyword(sym::pure) {
402 try_set_option(p, args, sym::pure, ast::InlineAsmOptions::PURE);
403 } else if !is_global_asm && p.eat_keyword(sym::nomem) {
404 try_set_option(p, args, sym::nomem, ast::InlineAsmOptions::NOMEM);
405 } else if !is_global_asm && p.eat_keyword(sym::readonly) {
406 try_set_option(p, args, sym::readonly, ast::InlineAsmOptions::READONLY);
407 } else if !is_global_asm && p.eat_keyword(sym::preserves_flags) {
408 try_set_option(p, args, sym::preserves_flags, ast::InlineAsmOptions::PRESERVES_FLAGS);
409 } else if !is_global_asm && p.eat_keyword(sym::noreturn) {
410 try_set_option(p, args, sym::noreturn, ast::InlineAsmOptions::NORETURN);
411 } else if !is_global_asm && p.eat_keyword(sym::nostack) {
412 try_set_option(p, args, sym::nostack, ast::InlineAsmOptions::NOSTACK);
413 } else if p.eat_keyword(sym::att_syntax) {
414 try_set_option(p, args, sym::att_syntax, ast::InlineAsmOptions::ATT_SYNTAX);
415 } else if p.eat_keyword(kw::Raw) {
416 try_set_option(p, args, kw::Raw, ast::InlineAsmOptions::RAW);
418 return p.unexpected();
421 // Allow trailing commas
422 if p.eat(&token::CloseDelim(token::DelimToken::Paren)) {
425 p.expect(&token::Comma)?;
428 let new_span = span_start.to(p.prev_token.span);
429 args.options_spans.push(new_span);
434 fn parse_clobber_abi<'a>(
437 ) -> Result<(), DiagnosticBuilder<'a>> {
438 let span_start = p.prev_token.span;
440 p.expect(&token::OpenDelim(token::DelimToken::Paren))?;
442 let clobber_abi = match p.parse_str_lit() {
443 Ok(str_lit) => str_lit.symbol_unescaped,
445 let span = opt_lit.map_or(p.token.span, |lit| lit.span);
446 let mut err = p.sess.span_diagnostic.struct_span_err(span, "expected string literal");
447 err.span_label(span, "not a string literal");
452 p.expect(&token::CloseDelim(token::DelimToken::Paren))?;
454 let new_span = span_start.to(p.prev_token.span);
456 if let Some((_, prev_span)) = args.clobber_abi {
460 .struct_span_err(new_span, "clobber_abi specified multiple times");
461 err.span_label(prev_span, "clobber_abi previously specified here");
463 } else if !args.options_spans.is_empty() {
467 .struct_span_err(new_span, "clobber_abi is not allowed after options");
468 err.span_labels(args.options_spans.clone(), "options");
472 args.clobber_abi = Some((clobber_abi, new_span));
479 explicit_reg: &mut bool,
480 ) -> Result<ast::InlineAsmRegOrRegClass, DiagnosticBuilder<'a>> {
481 p.expect(&token::OpenDelim(token::DelimToken::Paren))?;
482 let result = match p.token.uninterpolate().kind {
483 token::Ident(name, false) => ast::InlineAsmRegOrRegClass::RegClass(name),
484 token::Literal(token::Lit { kind: token::LitKind::Str, symbol, suffix: _ }) => {
485 *explicit_reg = true;
486 ast::InlineAsmRegOrRegClass::Reg(symbol)
490 p.struct_span_err(p.token.span, "expected register class or explicit register")
495 p.expect(&token::CloseDelim(token::DelimToken::Paren))?;
499 fn expand_preparsed_asm(ecx: &mut ExtCtxt<'_>, args: AsmArgs) -> Option<ast::InlineAsm> {
500 let mut template = vec![];
501 // Register operands are implicitly used since they are not allowed to be
502 // referenced in the template string.
503 let mut used = vec![false; args.operands.len()];
504 for pos in &args.reg_args {
507 let named_pos: FxHashMap<usize, Symbol> =
508 args.named_args.iter().map(|(&sym, &idx)| (idx, sym)).collect();
509 let mut line_spans = Vec::with_capacity(args.templates.len());
512 let mut template_strs = Vec::with_capacity(args.templates.len());
514 for template_expr in args.templates.into_iter() {
515 if !template.is_empty() {
516 template.push(ast::InlineAsmTemplatePiece::String("\n".to_string()));
519 let msg = "asm template must be a string literal";
520 let template_sp = template_expr.span;
521 let (template_str, template_style, template_span) =
522 match expr_to_spanned_string(ecx, template_expr, msg) {
523 Ok(template_part) => template_part,
525 if let Some((mut err, _)) = err {
532 let str_style = match template_style {
533 ast::StrStyle::Cooked => None,
534 ast::StrStyle::Raw(raw) => Some(raw as usize),
537 let template_snippet = ecx.source_map().span_to_snippet(template_sp).ok();
540 template_snippet.as_ref().map(|s| Symbol::intern(s)),
543 let template_str = &template_str.as_str();
545 if let Some(InlineAsmArch::X86 | InlineAsmArch::X86_64) = ecx.sess.asm_arch {
546 let find_span = |needle: &str| -> Span {
547 if let Some(snippet) = &template_snippet {
548 if let Some(pos) = snippet.find(needle) {
551 .find(|c| matches!(c, '\n' | ';' | '\\' | '"'))
552 .unwrap_or(snippet[pos..].len() - 1);
553 let inner = InnerSpan::new(pos, end);
554 return template_sp.from_inner(inner);
560 if template_str.contains(".intel_syntax") {
561 ecx.parse_sess().buffer_lint(
562 lint::builtin::BAD_ASM_STYLE,
563 find_span(".intel_syntax"),
564 ecx.current_expansion.lint_node_id,
565 "avoid using `.intel_syntax`, Intel syntax is the default",
568 if template_str.contains(".att_syntax") {
569 ecx.parse_sess().buffer_lint(
570 lint::builtin::BAD_ASM_STYLE,
571 find_span(".att_syntax"),
572 ecx.current_expansion.lint_node_id,
573 "avoid using `.att_syntax`, prefer using `options(att_syntax)` instead",
578 // Don't treat raw asm as a format string.
579 if args.options.contains(ast::InlineAsmOptions::RAW) {
580 template.push(ast::InlineAsmTemplatePiece::String(template_str.to_string()));
581 let template_num_lines = 1 + template_str.matches('\n').count();
582 line_spans.extend(std::iter::repeat(template_sp).take(template_num_lines));
586 let mut parser = parse::Parser::new(
591 parse::ParseMode::InlineAsm,
593 parser.curarg = curarg;
595 let mut unverified_pieces = Vec::new();
596 while let Some(piece) = parser.next() {
597 if !parser.errors.is_empty() {
600 unverified_pieces.push(piece);
604 if !parser.errors.is_empty() {
605 let err = parser.errors.remove(0);
606 let err_sp = template_span.from_inner(err.span);
607 let msg = &format!("invalid asm template string: {}", err.description);
608 let mut e = ecx.struct_span_err(err_sp, msg);
609 e.span_label(err_sp, err.label + " in asm template string");
610 if let Some(note) = err.note {
613 if let Some((label, span)) = err.secondary_label {
614 let err_sp = template_span.from_inner(span);
615 e.span_label(err_sp, label);
621 curarg = parser.curarg;
623 let mut arg_spans = parser.arg_places.iter().map(|span| template_span.from_inner(*span));
624 for piece in unverified_pieces {
626 parse::Piece::String(s) => {
627 template.push(ast::InlineAsmTemplatePiece::String(s.to_string()))
629 parse::Piece::NextArgument(arg) => {
630 let span = arg_spans.next().unwrap_or(template_sp);
632 let operand_idx = match arg.position {
633 parse::ArgumentIs(idx) | parse::ArgumentImplicitlyIs(idx) => {
634 if idx >= args.operands.len()
635 || named_pos.contains_key(&idx)
636 || args.reg_args.contains(&idx)
638 let msg = format!("invalid reference to argument at index {}", idx);
639 let mut err = ecx.struct_span_err(span, &msg);
640 err.span_label(span, "from here");
642 let positional_args = args.operands.len()
643 - args.named_args.len()
644 - args.reg_args.len();
645 let positional = if positional_args != args.operands.len() {
650 let msg = match positional_args {
651 0 => format!("no {}arguments were given", positional),
652 1 => format!("there is 1 {}argument", positional),
653 x => format!("there are {} {}arguments", x, positional),
657 if named_pos.contains_key(&idx) {
658 err.span_label(args.operands[idx].1, "named argument");
660 args.operands[idx].1,
661 "named arguments cannot be referenced by position",
663 } else if args.reg_args.contains(&idx) {
665 args.operands[idx].1,
666 "explicit register argument",
669 args.operands[idx].1,
670 "explicit register arguments cannot be used in the asm template",
679 parse::ArgumentNamed(name) => match args.named_args.get(&name) {
680 Some(&idx) => Some(idx),
682 let msg = format!("there is no argument named `{}`", name);
683 ecx.struct_span_err(span, &msg[..]).emit();
689 let mut chars = arg.format.ty.chars();
690 let mut modifier = chars.next();
691 if chars.next().is_some() {
695 .map(|sp| template_sp.from_inner(sp))
696 .unwrap_or(template_sp);
699 "asm template modifier must be a single character",
705 if let Some(operand_idx) = operand_idx {
706 used[operand_idx] = true;
707 template.push(ast::InlineAsmTemplatePiece::Placeholder {
717 if parser.line_spans.is_empty() {
718 let template_num_lines = 1 + template_str.matches('\n').count();
719 line_spans.extend(std::iter::repeat(template_sp).take(template_num_lines));
721 line_spans.extend(parser.line_spans.iter().map(|span| template_span.from_inner(*span)));
725 let mut unused_operands = vec![];
726 let mut help_str = String::new();
727 for (idx, used) in used.into_iter().enumerate() {
729 let msg = if let Some(sym) = named_pos.get(&idx) {
730 help_str.push_str(&format!(" {{{}}}", sym));
731 "named argument never used"
733 help_str.push_str(&format!(" {{{}}}", idx));
734 "argument never used"
736 unused_operands.push((args.operands[idx].1, msg));
739 match unused_operands.len() {
742 let (sp, msg) = unused_operands.into_iter().next().unwrap();
743 let mut err = ecx.struct_span_err(sp, msg);
744 err.span_label(sp, msg);
746 "if this argument is intentionally unused, \
747 consider using it in an asm comment: `\"/*{} */\"`",
753 let mut err = ecx.struct_span_err(
754 unused_operands.iter().map(|&(sp, _)| sp).collect::<Vec<Span>>(),
755 "multiple unused asm arguments",
757 for (sp, msg) in unused_operands {
758 err.span_label(sp, msg);
761 "if these arguments are intentionally unused, \
762 consider using them in an asm comment: `\"/*{} */\"`",
769 Some(ast::InlineAsm {
771 template_strs: template_strs.into_boxed_slice(),
772 operands: args.operands,
773 clobber_abi: args.clobber_abi,
774 options: args.options,
779 pub fn expand_asm<'cx>(
780 ecx: &'cx mut ExtCtxt<'_>,
783 ) -> Box<dyn base::MacResult + 'cx> {
784 match parse_args(ecx, sp, tts, false) {
786 let expr = if let Some(inline_asm) = expand_preparsed_asm(ecx, args) {
788 id: ast::DUMMY_NODE_ID,
789 kind: ast::ExprKind::InlineAsm(P(inline_asm)),
791 attrs: ast::AttrVec::new(),
795 DummyResult::raw_expr(sp, true)
806 pub fn expand_global_asm<'cx>(
807 ecx: &'cx mut ExtCtxt<'_>,
810 ) -> Box<dyn base::MacResult + 'cx> {
811 match parse_args(ecx, sp, tts, true) {
813 if let Some(inline_asm) = expand_preparsed_asm(ecx, args) {
814 MacEager::items(smallvec![P(ast::Item {
815 ident: Ident::empty(),
817 id: ast::DUMMY_NODE_ID,
818 kind: ast::ItemKind::GlobalAsm(inline_asm),
819 vis: ast::Visibility {
820 span: sp.shrink_to_lo(),
821 kind: ast::VisibilityKind::Inherited,
824 span: ecx.with_def_site_ctxt(sp),