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_span::symbol::{kw, sym, Symbol};
11 use rustc_span::{InnerSpan, Span};
14 templates: Vec<P<ast::Expr>>,
15 operands: Vec<(ast::InlineAsmOperand, Span)>,
16 named_args: FxHashMap<Symbol, usize>,
17 reg_args: FxHashSet<usize>,
18 options: ast::InlineAsmOptions,
19 options_spans: Vec<Span>,
23 ecx: &mut ExtCtxt<'a>,
26 ) -> Result<AsmArgs, DiagnosticBuilder<'a>> {
27 let mut p = ecx.new_parser_from_tts(tts);
29 if p.token == token::Eof {
30 return Err(ecx.struct_span_err(sp, "requires at least a template string argument"));
33 // Detect use of the legacy llvm_asm! syntax (which used to be called asm!)
34 if p.look_ahead(1, |t| *t == token::Colon || *t == token::ModSep) {
36 ecx.struct_span_err(sp, "the legacy LLVM-style asm! syntax is no longer supported");
37 err.note("consider migrating to the new asm! syntax specified in RFC 2873");
38 err.note("alternatively, switch to llvm_asm! to keep your code working as it is");
40 // Find the span of the "asm!" so that we can offer an automatic suggestion
41 let asm_span = sp.from_inner(InnerSpan::new(0, 4));
42 if let Ok(s) = ecx.source_map().span_to_snippet(asm_span) {
48 Applicability::MachineApplicable,
55 let first_template = p.parse_expr()?;
56 let mut args = AsmArgs {
57 templates: vec![first_template],
59 named_args: FxHashMap::default(),
60 reg_args: FxHashSet::default(),
61 options: ast::InlineAsmOptions::empty(),
62 options_spans: vec![],
65 let mut allow_templates = true;
66 while p.token != token::Eof {
67 if !p.eat(&token::Comma) {
69 // After a template string, we always expect *only* a comma...
70 let mut err = ecx.struct_span_err(p.token.span, "expected token: `,`");
71 err.span_label(p.token.span, "expected `,`");
72 p.maybe_annotate_with_ascription(&mut err, false);
75 // ...after that delegate to `expect` to also include the other expected tokens.
76 return Err(p.expect(&token::Comma).err().unwrap());
79 if p.token == token::Eof {
81 } // accept trailing commas
84 if p.eat(&token::Ident(sym::options, false)) {
85 parse_options(&mut p, &mut args)?;
86 allow_templates = false;
90 let span_start = p.token.span;
92 // Parse operand names
93 let name = if p.token.is_ident() && p.look_ahead(1, |t| *t == token::Eq) {
94 let (ident, _) = p.token.ident().unwrap();
96 p.expect(&token::Eq)?;
97 allow_templates = false;
103 let mut explicit_reg = false;
104 let op = if p.eat(&token::Ident(kw::In, false)) {
105 let reg = parse_reg(&mut p, &mut explicit_reg)?;
106 let expr = p.parse_expr()?;
107 ast::InlineAsmOperand::In { reg, expr }
108 } else if p.eat(&token::Ident(sym::out, false)) {
109 let reg = parse_reg(&mut p, &mut explicit_reg)?;
110 let expr = if p.eat_keyword(kw::Underscore) { None } else { Some(p.parse_expr()?) };
111 ast::InlineAsmOperand::Out { reg, expr, late: false }
112 } else if p.eat(&token::Ident(sym::lateout, false)) {
113 let reg = parse_reg(&mut p, &mut explicit_reg)?;
114 let expr = if p.eat_keyword(kw::Underscore) { None } else { Some(p.parse_expr()?) };
115 ast::InlineAsmOperand::Out { reg, expr, late: true }
116 } else if p.eat(&token::Ident(sym::inout, false)) {
117 let reg = parse_reg(&mut p, &mut explicit_reg)?;
118 let expr = p.parse_expr()?;
119 if p.eat(&token::FatArrow) {
121 if p.eat_keyword(kw::Underscore) { None } else { Some(p.parse_expr()?) };
122 ast::InlineAsmOperand::SplitInOut { reg, in_expr: expr, out_expr, late: false }
124 ast::InlineAsmOperand::InOut { reg, expr, late: false }
126 } else if p.eat(&token::Ident(sym::inlateout, false)) {
127 let reg = parse_reg(&mut p, &mut explicit_reg)?;
128 let expr = p.parse_expr()?;
129 if p.eat(&token::FatArrow) {
131 if p.eat_keyword(kw::Underscore) { None } else { Some(p.parse_expr()?) };
132 ast::InlineAsmOperand::SplitInOut { reg, in_expr: expr, out_expr, late: true }
134 ast::InlineAsmOperand::InOut { reg, expr, late: true }
136 } else if p.eat(&token::Ident(kw::Const, false)) {
137 let expr = p.parse_expr()?;
138 ast::InlineAsmOperand::Const { expr }
139 } else if p.eat(&token::Ident(sym::sym, false)) {
140 let expr = p.parse_expr()?;
142 ast::ExprKind::Path(..) => {}
145 .struct_span_err(expr.span, "argument to `sym` must be a path expression");
149 ast::InlineAsmOperand::Sym { expr }
150 } else if allow_templates {
151 let template = p.parse_expr()?;
152 // If it can't possibly expand to a string, provide diagnostics here to include other
153 // things it could have been.
154 match template.kind {
155 ast::ExprKind::Lit(ast::Lit { kind: ast::LitKind::Str(..), .. }) => {}
156 ast::ExprKind::MacCall(..) => {}
158 let errstr = "expected operand, options, or additional template string";
159 let mut err = ecx.struct_span_err(template.span, errstr);
160 err.span_label(template.span, errstr);
164 args.templates.push(template);
167 return Err(p.expect_one_of(&[], &[]).unwrap_err());
170 allow_templates = false;
171 let span = span_start.to(p.prev_token.span);
172 let slot = args.operands.len();
173 args.operands.push((op, span));
175 // Validate the order of named, positional & explicit register operands and options. We do
176 // this at the end once we have the full span of the argument available.
177 if !args.options_spans.is_empty() {
178 ecx.struct_span_err(span, "arguments are not allowed after options")
179 .span_labels(args.options_spans.clone(), "previous options")
180 .span_label(span, "argument")
185 ecx.struct_span_err(span, "explicit register arguments cannot have names").emit();
187 args.reg_args.insert(slot);
188 } else if let Some(name) = name {
189 if let Some(&prev) = args.named_args.get(&name) {
190 ecx.struct_span_err(span, &format!("duplicate argument named `{}`", name))
191 .span_label(args.operands[prev].1, "previously here")
192 .span_label(span, "duplicate argument")
196 if !args.reg_args.is_empty() {
197 let mut err = ecx.struct_span_err(
199 "named arguments cannot follow explicit register arguments",
201 err.span_label(span, "named argument");
202 for pos in &args.reg_args {
203 err.span_label(args.operands[*pos].1, "explicit register argument");
207 args.named_args.insert(name, slot);
209 if !args.named_args.is_empty() || !args.reg_args.is_empty() {
210 let mut err = ecx.struct_span_err(
212 "positional arguments cannot follow named arguments \
213 or explicit register arguments",
215 err.span_label(span, "positional argument");
216 for pos in args.named_args.values() {
217 err.span_label(args.operands[*pos].1, "named argument");
219 for pos in &args.reg_args {
220 err.span_label(args.operands[*pos].1, "explicit register argument");
227 if args.options.contains(ast::InlineAsmOptions::NOMEM)
228 && args.options.contains(ast::InlineAsmOptions::READONLY)
230 let spans = args.options_spans.clone();
231 ecx.struct_span_err(spans, "the `nomem` and `readonly` options are mutually exclusive")
234 if args.options.contains(ast::InlineAsmOptions::PURE)
235 && args.options.contains(ast::InlineAsmOptions::NORETURN)
237 let spans = args.options_spans.clone();
238 ecx.struct_span_err(spans, "the `pure` and `noreturn` options are mutually exclusive")
241 if args.options.contains(ast::InlineAsmOptions::PURE)
242 && !args.options.intersects(ast::InlineAsmOptions::NOMEM | ast::InlineAsmOptions::READONLY)
244 let spans = args.options_spans.clone();
247 "the `pure` option must be combined with either `nomem` or `readonly`",
252 let mut have_real_output = false;
253 let mut outputs_sp = vec![];
254 for (op, op_sp) in &args.operands {
256 ast::InlineAsmOperand::Out { expr, .. }
257 | ast::InlineAsmOperand::SplitInOut { out_expr: expr, .. } => {
258 outputs_sp.push(*op_sp);
259 have_real_output |= expr.is_some();
261 ast::InlineAsmOperand::InOut { .. } => {
262 outputs_sp.push(*op_sp);
263 have_real_output = true;
268 if args.options.contains(ast::InlineAsmOptions::PURE) && !have_real_output {
270 args.options_spans.clone(),
271 "asm with `pure` option must have at least one output",
275 if args.options.contains(ast::InlineAsmOptions::NORETURN) && !outputs_sp.is_empty() {
277 .struct_span_err(outputs_sp, "asm outputs are not allowed with the `noreturn` option");
279 // Bail out now since this is likely to confuse MIR
286 /// Report a duplicate option error.
288 /// This function must be called immediately after the option token is parsed.
289 /// Otherwise, the suggestion will be incorrect.
290 fn err_duplicate_option<'a>(p: &mut Parser<'a>, symbol: Symbol, span: Span) {
294 .struct_span_err(span, &format!("the `{}` option was already provided", symbol));
295 err.span_label(span, "this option was already provided");
298 let mut full_span = span;
299 if p.token.kind == token::Comma {
300 full_span = full_span.to(p.token.span);
302 err.tool_only_span_suggestion(
304 "remove this option",
306 Applicability::MachineApplicable,
312 /// Try to set the provided option in the provided `AsmArgs`.
313 /// If it is already set, report a duplicate option error.
315 /// This function must be called immediately after the option token is parsed.
316 /// Otherwise, the error will not point to the correct spot.
317 fn try_set_option<'a>(
321 option: ast::InlineAsmOptions,
323 if !args.options.contains(option) {
324 args.options |= option;
326 err_duplicate_option(p, symbol, p.prev_token.span);
330 fn parse_options<'a>(p: &mut Parser<'a>, args: &mut AsmArgs) -> Result<(), DiagnosticBuilder<'a>> {
331 let span_start = p.prev_token.span;
333 p.expect(&token::OpenDelim(token::DelimToken::Paren))?;
335 while !p.eat(&token::CloseDelim(token::DelimToken::Paren)) {
336 if p.eat(&token::Ident(sym::pure, false)) {
337 try_set_option(p, args, sym::pure, ast::InlineAsmOptions::PURE);
338 } else if p.eat(&token::Ident(sym::nomem, false)) {
339 try_set_option(p, args, sym::nomem, ast::InlineAsmOptions::NOMEM);
340 } else if p.eat(&token::Ident(sym::readonly, false)) {
341 try_set_option(p, args, sym::readonly, ast::InlineAsmOptions::READONLY);
342 } else if p.eat(&token::Ident(sym::preserves_flags, false)) {
343 try_set_option(p, args, sym::preserves_flags, ast::InlineAsmOptions::PRESERVES_FLAGS);
344 } else if p.eat(&token::Ident(sym::noreturn, false)) {
345 try_set_option(p, args, sym::noreturn, ast::InlineAsmOptions::NORETURN);
346 } else if p.eat(&token::Ident(sym::nostack, false)) {
347 try_set_option(p, args, sym::nostack, ast::InlineAsmOptions::NOSTACK);
349 p.expect(&token::Ident(sym::att_syntax, false))?;
350 try_set_option(p, args, sym::att_syntax, ast::InlineAsmOptions::ATT_SYNTAX);
353 // Allow trailing commas
354 if p.eat(&token::CloseDelim(token::DelimToken::Paren)) {
357 p.expect(&token::Comma)?;
360 let new_span = span_start.to(p.prev_token.span);
361 args.options_spans.push(new_span);
368 explicit_reg: &mut bool,
369 ) -> Result<ast::InlineAsmRegOrRegClass, DiagnosticBuilder<'a>> {
370 p.expect(&token::OpenDelim(token::DelimToken::Paren))?;
371 let result = match p.token.kind {
372 token::Ident(name, false) => ast::InlineAsmRegOrRegClass::RegClass(name),
373 token::Literal(token::Lit { kind: token::LitKind::Str, symbol, suffix: _ }) => {
374 *explicit_reg = true;
375 ast::InlineAsmRegOrRegClass::Reg(symbol)
379 p.struct_span_err(p.token.span, "expected register class or explicit register")
384 p.expect(&token::CloseDelim(token::DelimToken::Paren))?;
388 fn expand_preparsed_asm(ecx: &mut ExtCtxt<'_>, sp: Span, args: AsmArgs) -> P<ast::Expr> {
389 let mut template = vec![];
390 // Register operands are implicitly used since they are not allowed to be
391 // referenced in the template string.
392 let mut used = vec![false; args.operands.len()];
393 for pos in &args.reg_args {
396 let named_pos: FxHashMap<usize, Symbol> =
397 args.named_args.iter().map(|(&sym, &idx)| (idx, sym)).collect();
398 let mut line_spans = Vec::with_capacity(args.templates.len());
401 for template_expr in args.templates.into_iter() {
402 if !template.is_empty() {
403 template.push(ast::InlineAsmTemplatePiece::String("\n".to_string()));
406 let msg = "asm template must be a string literal";
407 let template_sp = template_expr.span;
408 let (template_str, template_style, template_span) =
409 match expr_to_spanned_string(ecx, template_expr, msg) {
410 Ok(template_part) => template_part,
412 if let Some(mut err) = err {
415 return DummyResult::raw_expr(sp, true);
419 let str_style = match template_style {
420 ast::StrStyle::Cooked => None,
421 ast::StrStyle::Raw(raw) => Some(raw as usize),
424 let template_str = &template_str.as_str();
425 let template_snippet = ecx.source_map().span_to_snippet(template_sp).ok();
426 let mut parser = parse::Parser::new(
431 parse::ParseMode::InlineAsm,
433 parser.curarg = curarg;
435 let mut unverified_pieces = Vec::new();
436 while let Some(piece) = parser.next() {
437 if !parser.errors.is_empty() {
440 unverified_pieces.push(piece);
444 if !parser.errors.is_empty() {
445 let err = parser.errors.remove(0);
446 let err_sp = template_span.from_inner(err.span);
447 let msg = &format!("invalid asm template string: {}", err.description);
448 let mut e = ecx.struct_span_err(err_sp, msg);
449 e.span_label(err_sp, err.label + " in asm template string");
450 if let Some(note) = err.note {
453 if let Some((label, span)) = err.secondary_label {
454 let err_sp = template_span.from_inner(span);
455 e.span_label(err_sp, label);
458 return DummyResult::raw_expr(sp, true);
461 curarg = parser.curarg;
463 let mut arg_spans = parser.arg_places.iter().map(|span| template_span.from_inner(*span));
464 for piece in unverified_pieces {
466 parse::Piece::String(s) => {
467 template.push(ast::InlineAsmTemplatePiece::String(s.to_string()))
469 parse::Piece::NextArgument(arg) => {
470 let span = arg_spans.next().unwrap_or(template_sp);
472 let operand_idx = match arg.position {
473 parse::ArgumentIs(idx) | parse::ArgumentImplicitlyIs(idx) => {
474 if idx >= args.operands.len()
475 || named_pos.contains_key(&idx)
476 || args.reg_args.contains(&idx)
478 let msg = format!("invalid reference to argument at index {}", idx);
479 let mut err = ecx.struct_span_err(span, &msg);
480 err.span_label(span, "from here");
482 let positional_args = args.operands.len()
483 - args.named_args.len()
484 - args.reg_args.len();
485 let positional = if positional_args != args.operands.len() {
490 let msg = match positional_args {
491 0 => format!("no {}arguments were given", positional),
492 1 => format!("there is 1 {}argument", positional),
493 x => format!("there are {} {}arguments", x, positional),
497 if named_pos.contains_key(&idx) {
498 err.span_label(args.operands[idx].1, "named argument");
500 args.operands[idx].1,
501 "named arguments cannot be referenced by position",
503 } else if args.reg_args.contains(&idx) {
505 args.operands[idx].1,
506 "explicit register argument",
509 args.operands[idx].1,
510 "explicit register arguments cannot be used in the asm template",
519 parse::ArgumentNamed(name) => match args.named_args.get(&name) {
520 Some(&idx) => Some(idx),
522 let msg = format!("there is no argument named `{}`", name);
523 ecx.struct_span_err(span, &msg[..]).emit();
529 let mut chars = arg.format.ty.chars();
530 let mut modifier = chars.next();
531 if chars.next().is_some() {
535 .map(|sp| template_sp.from_inner(sp))
536 .unwrap_or(template_sp);
539 "asm template modifier must be a single character",
545 if let Some(operand_idx) = operand_idx {
546 used[operand_idx] = true;
547 template.push(ast::InlineAsmTemplatePiece::Placeholder {
557 if parser.line_spans.is_empty() {
558 let template_num_lines = 1 + template_str.matches('\n').count();
559 line_spans.extend(std::iter::repeat(template_sp).take(template_num_lines));
561 line_spans.extend(parser.line_spans.iter().map(|span| template_span.from_inner(*span)));
565 let mut unused_operands = vec![];
566 let mut help_str = String::new();
567 for (idx, used) in used.into_iter().enumerate() {
569 let msg = if let Some(sym) = named_pos.get(&idx) {
570 help_str.push_str(&format!(" {{{}}}", sym));
571 "named argument never used"
573 help_str.push_str(&format!(" {{{}}}", idx));
574 "argument never used"
576 unused_operands.push((args.operands[idx].1, msg));
579 match unused_operands.len() {
582 let (sp, msg) = unused_operands.into_iter().next().unwrap();
583 let mut err = ecx.struct_span_err(sp, msg);
584 err.span_label(sp, msg);
586 "if this argument is intentionally unused, \
587 consider using it in an asm comment: `\"/*{} */\"`",
593 let mut err = ecx.struct_span_err(
594 unused_operands.iter().map(|&(sp, _)| sp).collect::<Vec<Span>>(),
595 "multiple unused asm arguments",
597 for (sp, msg) in unused_operands {
598 err.span_label(sp, msg);
601 "if these arguments are intentionally unused, \
602 consider using them in an asm comment: `\"/*{} */\"`",
610 ast::InlineAsm { template, operands: args.operands, options: args.options, line_spans };
612 id: ast::DUMMY_NODE_ID,
613 kind: ast::ExprKind::InlineAsm(P(inline_asm)),
615 attrs: ast::AttrVec::new(),
620 pub fn expand_asm<'cx>(
621 ecx: &'cx mut ExtCtxt<'_>,
624 ) -> Box<dyn base::MacResult + 'cx> {
625 match parse_args(ecx, sp, tts) {
626 Ok(args) => MacEager::expr(expand_preparsed_asm(ecx, sp, args)),