Forbid asm unwind to work with labels

Author: nbdd0121

compiler/rustc_builtin_macros/messages.ftl

@@ -19,6 +19,8 @@ builtin_macros_asm_expected_other = expected operand, {$is_global_asm ->
 
 builtin_macros_asm_explicit_register_name = explicit register arguments cannot have names
 
+builtin_macros_asm_mayunwind = asm labels are not allowed with the `may_unwind` option
+
 builtin_macros_asm_modifier_invalid = asm template modifier must be a single character
 
 builtin_macros_asm_mutually_exclusive = the `{$opt1}` and `{$opt2}` options are mutually exclusive

compiler/rustc_builtin_macros/src/asm.rs

@@ -245,6 +245,7 @@ pub fn parse_asm_args<'a>(
  let mut have_real_output = false;
  let mut outputs_sp = vec![];
  let mut regclass_outputs = vec![];
+ let mut labels_sp = vec![];
  for (op, op_sp) in &args.operands {
  match op {
  ast::InlineAsmOperand::Out { reg, expr, .. }
@@ -262,6 +263,9 @@ pub fn parse_asm_args<'a>(
  regclass_outputs.push(*op_sp);
  }
  }
+ ast::InlineAsmOperand::Label { .. } => {
+ labels_sp.push(*op_sp);
+ }
  _ => {}
  }
  }
@@ -273,6 +277,9 @@ pub fn parse_asm_args<'a>(
  // Bail out now since this is likely to confuse MIR
  return Err(err);
  }
+ if args.options.contains(ast::InlineAsmOptions::MAY_UNWIND) && !labels_sp.is_empty() {
+ dcx.emit_err(errors::AsmMayUnwind { labels_sp });
+ }
 
  if args.clobber_abis.len() > 0 {
  if is_global_asm {

compiler/rustc_builtin_macros/src/errors.rs

@@ -787,6 +787,13 @@ pub(crate) struct AsmNoReturn {
  pub(crate) outputs_sp: Vec<Span>,
 }
 
+#[derive(Diagnostic)]
+#[diag(builtin_macros_asm_mayunwind)]
+pub(crate) struct AsmMayUnwind {
+ #[primary_span]
+ pub(crate) labels_sp: Vec<Span>,
+}
+
 #[derive(Diagnostic)]
 #[diag(builtin_macros_global_asm_clobber_abi)]
 pub(crate) struct GlobalAsmClobberAbi {