bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Rollup merge of #119195 - asquared31415:named_asm_labels_fix, r=Amanieu

Browse source 
Make named_asm_labels lint not trigger on unicode and trigger on format args

Someone showed me some cursed code that used format args to create named labels, and rustc wasn't linting on that.  Additionally while fixing that, I noticed that Unicode alphabetic characters were being used as part of labels, when they are not actually permitted in labels.

r? ```@Amanieu```
This commit is contained in:
Matthias Krüger 2024-01-04 08:33:22 +01:00 • committed by GitHub
commit 13840b3b1d
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
3 changed files with 162 additions and 24 deletions
Download patch file Download diff file Expand all files Collapse all files

62
compiler/rustc_lint/src/builtin.rs
View file

@ -2734,10 +2734,13 @@ impl<'tcx> LateLintPass<'tcx> for NamedAsmLabels {
#[allow(rustc::diagnostic_outside_of_impl)]
fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'tcx>) {
if let hir::Expr {
kind: hir::ExprKind::InlineAsm(hir::InlineAsm { template_strs, .. }),
kind: hir::ExprKind::InlineAsm(hir::InlineAsm { template_strs, options, .. }),
..
} = expr
{
// asm with `options(raw)` does not do replacement with `{` and `}`.
let raw = options.contains(InlineAsmOptions::RAW);
for (template_sym, template_snippet, template_span) in template_strs.iter() {
let template_str = template_sym.as_str();
let find_label_span = |needle: &str| -> Option<Span> {
@ -2763,24 +2766,57 @@ impl<'tcx> LateLintPass<'tcx> for NamedAsmLabels {
for statement in statements {
// If there's a comment, trim it from the statement
let statement = statement.find("//").map_or(statement, |idx| &statement[..idx]);
// In this loop, if there is ever a non-label, no labels can come after it.
let mut start_idx = 0;
for (idx, _) in statement.match_indices(':') {
'label_loop: for (idx, _) in statement.match_indices(':') {
let possible_label = statement[start_idx..idx].trim();
let mut chars = possible_label.chars();
let Some(c) = chars.next() else {
// Empty string means a leading ':' in this section, which is not a label
break;
let Some(start) = chars.next() else {
// Empty string means a leading ':' in this section, which is not a label.
break 'label_loop;
};
// A label starts with an alphabetic character or . or _ and continues with alphanumeric characters, _, or $
if (c.is_alphabetic() || matches!(c, '.' | '_'))
&& chars.all(|c| c.is_alphanumeric() || matches!(c, '_' | '$'))
{
found_labels.push(possible_label);
} else {
// If we encounter a non-label, there cannot be any further labels, so stop checking
break;
// Whether a { bracket has been seen and its } hasn't been found yet.
let mut in_bracket = false;
// A label starts with an ASCII alphabetic character or . or _
// A label can also start with a format arg, if it's not a raw asm block.
if !raw && start == '{' {
in_bracket = true;
} else if !(start.is_ascii_alphabetic() || matches!(start, '.' | '_')) {
break 'label_loop;
}
// Labels continue with ASCII alphanumeric characters, _, or $
for c in chars {
// Inside a template format arg, any character is permitted for the puproses of label detection
// because we assume that it can be replaced with some other valid label string later.
// `options(raw)` asm blocks cannot have format args, so they are excluded from this special case.
if !raw && in_bracket {
if c == '{' {
// Nested brackets are not allowed in format args, this cannot be a label.
break 'label_loop;
}
if c == '}' {
// The end of the format arg.
in_bracket = false;
}
} else if !raw && c == '{' {
// Start of a format arg.
in_bracket = true;
} else {
if !(c.is_ascii_alphanumeric() || matches!(c, '_' | '$')) {
// The potential label had an invalid character inside it, it cannot be a label.
break 'label_loop;
}
}
}
// If all characters passed the label checks, this is likely a label.
found_labels.push(possible_label);
start_idx = idx + 1;
}
}