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_span: Option<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(),
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 let Some(options_span) = args.options_span {
178 ecx.struct_span_err(span, "arguments are not allowed after options")
179 .span_label(options_span, "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 span = args.options_span.unwrap();
231 ecx.struct_span_err(span, "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 span = args.options_span.unwrap();
238 ecx.struct_span_err(span, "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 span = args.options_span.unwrap();
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_span.unwrap(),
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 fn parse_options<'a>(p: &mut Parser<'a>, args: &mut AsmArgs) -> Result<(), DiagnosticBuilder<'a>> {
287 let span_start = p.prev_token.span;
289 p.expect(&token::OpenDelim(token::DelimToken::Paren))?;
291 while !p.eat(&token::CloseDelim(token::DelimToken::Paren)) {
292 if p.eat(&token::Ident(sym::pure, false)) {
293 args.options |= ast::InlineAsmOptions::PURE;
294 } else if p.eat(&token::Ident(sym::nomem, false)) {
295 args.options |= ast::InlineAsmOptions::NOMEM;
296 } else if p.eat(&token::Ident(sym::readonly, false)) {
297 args.options |= ast::InlineAsmOptions::READONLY;
298 } else if p.eat(&token::Ident(sym::preserves_flags, false)) {
299 args.options |= ast::InlineAsmOptions::PRESERVES_FLAGS;
300 } else if p.eat(&token::Ident(sym::noreturn, false)) {
301 args.options |= ast::InlineAsmOptions::NORETURN;
302 } else if p.eat(&token::Ident(sym::nostack, false)) {
303 args.options |= ast::InlineAsmOptions::NOSTACK;
305 p.expect(&token::Ident(sym::att_syntax, false))?;
306 args.options |= ast::InlineAsmOptions::ATT_SYNTAX;
309 // Allow trailing commas
310 if p.eat(&token::CloseDelim(token::DelimToken::Paren)) {
313 p.expect(&token::Comma)?;
316 let new_span = span_start.to(p.prev_token.span);
317 if let Some(options_span) = args.options_span {
318 p.struct_span_err(new_span, "asm options cannot be specified multiple times")
319 .span_label(options_span, "previously here")
320 .span_label(new_span, "duplicate options")
323 args.options_span = Some(new_span);
331 explicit_reg: &mut bool,
332 ) -> Result<ast::InlineAsmRegOrRegClass, DiagnosticBuilder<'a>> {
333 p.expect(&token::OpenDelim(token::DelimToken::Paren))?;
334 let result = match p.token.kind {
335 token::Ident(name, false) => ast::InlineAsmRegOrRegClass::RegClass(name),
336 token::Literal(token::Lit { kind: token::LitKind::Str, symbol, suffix: _ }) => {
337 *explicit_reg = true;
338 ast::InlineAsmRegOrRegClass::Reg(symbol)
342 p.struct_span_err(p.token.span, "expected register class or explicit register")
347 p.expect(&token::CloseDelim(token::DelimToken::Paren))?;
351 fn expand_preparsed_asm(ecx: &mut ExtCtxt<'_>, sp: Span, args: AsmArgs) -> P<ast::Expr> {
352 let mut template = vec![];
353 // Register operands are implicitly used since they are not allowed to be
354 // referenced in the template string.
355 let mut used = vec![false; args.operands.len()];
356 for pos in &args.reg_args {
359 let named_pos: FxHashMap<usize, Symbol> =
360 args.named_args.iter().map(|(&sym, &idx)| (idx, sym)).collect();
361 let mut line_spans = Vec::with_capacity(args.templates.len());
364 for template_expr in args.templates.into_iter() {
365 if !template.is_empty() {
366 template.push(ast::InlineAsmTemplatePiece::String("\n".to_string()));
369 let msg = "asm template must be a string literal";
370 let template_sp = template_expr.span;
371 let (template_str, template_style, template_span) =
372 match expr_to_spanned_string(ecx, template_expr, msg) {
373 Ok(template_part) => template_part,
375 if let Some(mut err) = err {
378 return DummyResult::raw_expr(sp, true);
382 let str_style = match template_style {
383 ast::StrStyle::Cooked => None,
384 ast::StrStyle::Raw(raw) => Some(raw as usize),
387 let template_str = &template_str.as_str();
388 let template_snippet = ecx.source_map().span_to_snippet(template_sp).ok();
389 let mut parser = parse::Parser::new(
394 parse::ParseMode::InlineAsm,
396 parser.curarg = curarg;
398 let mut unverified_pieces = Vec::new();
399 while let Some(piece) = parser.next() {
400 if !parser.errors.is_empty() {
403 unverified_pieces.push(piece);
407 if !parser.errors.is_empty() {
408 let err = parser.errors.remove(0);
409 let err_sp = template_span.from_inner(err.span);
410 let msg = &format!("invalid asm template string: {}", err.description);
411 let mut e = ecx.struct_span_err(err_sp, msg);
412 e.span_label(err_sp, err.label + " in asm template string");
413 if let Some(note) = err.note {
416 if let Some((label, span)) = err.secondary_label {
417 let err_sp = template_span.from_inner(span);
418 e.span_label(err_sp, label);
421 return DummyResult::raw_expr(sp, true);
424 curarg = parser.curarg;
426 let mut arg_spans = parser.arg_places.iter().map(|span| template_span.from_inner(*span));
427 for piece in unverified_pieces {
429 parse::Piece::String(s) => {
430 template.push(ast::InlineAsmTemplatePiece::String(s.to_string()))
432 parse::Piece::NextArgument(arg) => {
433 let span = arg_spans.next().unwrap_or(template_sp);
435 let operand_idx = match arg.position {
436 parse::ArgumentIs(idx) | parse::ArgumentImplicitlyIs(idx) => {
437 if idx >= args.operands.len()
438 || named_pos.contains_key(&idx)
439 || args.reg_args.contains(&idx)
441 let msg = format!("invalid reference to argument at index {}", idx);
442 let mut err = ecx.struct_span_err(span, &msg);
443 err.span_label(span, "from here");
445 let positional_args = args.operands.len()
446 - args.named_args.len()
447 - args.reg_args.len();
448 let positional = if positional_args != args.operands.len() {
453 let msg = match positional_args {
454 0 => format!("no {}arguments were given", positional),
455 1 => format!("there is 1 {}argument", positional),
456 x => format!("there are {} {}arguments", x, positional),
460 if named_pos.contains_key(&idx) {
461 err.span_label(args.operands[idx].1, "named argument");
463 args.operands[idx].1,
464 "named arguments cannot be referenced by position",
466 } else if args.reg_args.contains(&idx) {
468 args.operands[idx].1,
469 "explicit register argument",
472 args.operands[idx].1,
473 "explicit register arguments cannot be used in the asm template",
482 parse::ArgumentNamed(name) => match args.named_args.get(&name) {
483 Some(&idx) => Some(idx),
485 let msg = format!("there is no argument named `{}`", name);
486 ecx.struct_span_err(span, &msg[..]).emit();
492 let mut chars = arg.format.ty.chars();
493 let mut modifier = chars.next();
494 if chars.next().is_some() {
498 .map(|sp| template_sp.from_inner(sp))
499 .unwrap_or(template_sp);
502 "asm template modifier must be a single character",
508 if let Some(operand_idx) = operand_idx {
509 used[operand_idx] = true;
510 template.push(ast::InlineAsmTemplatePiece::Placeholder {
520 if parser.line_spans.is_empty() {
521 let template_num_lines = 1 + template_str.matches('\n').count();
522 line_spans.extend(std::iter::repeat(template_sp).take(template_num_lines));
524 line_spans.extend(parser.line_spans.iter().map(|span| template_span.from_inner(*span)));
528 let mut unused_operands = vec![];
529 let mut help_str = String::new();
530 for (idx, used) in used.into_iter().enumerate() {
532 let msg = if let Some(sym) = named_pos.get(&idx) {
533 help_str.push_str(&format!(" {{{}}}", sym));
534 "named argument never used"
536 help_str.push_str(&format!(" {{{}}}", idx));
537 "argument never used"
539 unused_operands.push((args.operands[idx].1, msg));
542 match unused_operands.len() {
545 let (sp, msg) = unused_operands.into_iter().next().unwrap();
546 let mut err = ecx.struct_span_err(sp, msg);
547 err.span_label(sp, msg);
549 "if this argument is intentionally unused, \
550 consider using it in an asm comment: `\"/*{} */\"`",
556 let mut err = ecx.struct_span_err(
557 unused_operands.iter().map(|&(sp, _)| sp).collect::<Vec<Span>>(),
558 "multiple unused asm arguments",
560 for (sp, msg) in unused_operands {
561 err.span_label(sp, msg);
564 "if these arguments are intentionally unused, \
565 consider using them in an asm comment: `\"/*{} */\"`",
573 ast::InlineAsm { template, operands: args.operands, options: args.options, line_spans };
575 id: ast::DUMMY_NODE_ID,
576 kind: ast::ExprKind::InlineAsm(P(inline_asm)),
578 attrs: ast::AttrVec::new(),
583 pub fn expand_asm<'cx>(
584 ecx: &'cx mut ExtCtxt<'_>,
587 ) -> Box<dyn base::MacResult + 'cx> {
588 match parse_args(ecx, sp, tts) {
589 Ok(args) => MacEager::expr(expand_preparsed_asm(ecx, sp, args)),