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

asquared31415 · asquared31415 · commit 87fed9778e3d · 2023-12-21T18:02:56.000Z
diff --git a/compiler/rustc_lint/src/builtin.rs b/compiler/rustc_lint/src/builtin.rs
@@ -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;
                     }
                 }
diff --git a/tests/ui/asm/named-asm-labels.rs b/tests/ui/asm/named-asm-labels.rs
@@ -120,6 +120,27 @@ fn main() {
         // is there an example that is valid x86 for this test?
         asm!(":bbb nop");
 
+        // non-ascii characters are not allowed in labels, so should not trigger the lint
+        asm!("Ù: nop");
+        asm!("testÙ: nop");
+        asm!("_Ù_: nop");
+
+        // Format arguments should be conservatively assumed to be valid characters in labels
+        // Would emit `test_rax:` or similar
+        #[allow(asm_sub_register)]
+        {
+            asm!("test_{}: nop", in(reg) 10); //~ ERROR avoid using named labels
+        }
+        asm!("test_{}: nop", const 10); //~ ERROR avoid using named labels
+        asm!("test_{}: nop", sym main); //~ ERROR avoid using named labels
+        asm!("{}_test: nop", const 10); //~ ERROR avoid using named labels
+        asm!("test_{}_test: nop", const 10); //~ ERROR avoid using named labels
+        asm!("{}: nop", const 10); //~ ERROR avoid using named labels
+
+        asm!("{uwu}: nop", uwu = const 10); //~ ERROR avoid using named labels
+        asm!("{0}: nop", const 10); //~ ERROR avoid using named labels
+        asm!("{1}: nop", "/* {0} */", const 10, const 20); //~ ERROR avoid using named labels
+
         // Test include_str in asm
         asm!(include_str!("named-asm-labels.s")); //~ ERROR avoid using named labels
 
diff --git a/tests/ui/asm/named-asm-labels.stderr b/tests/ui/asm/named-asm-labels.stderr
@@ -245,7 +245,88 @@ LL |             ab: nop // ab: does foo
    = note: see the asm section of Rust By Example <https://doc.rust-lang.org/nightly/rust-by-example/unsafe/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:124:14
+  --> $DIR/named-asm-labels.rs:132:19
+   |
+LL |             asm!("test_{}: nop", in(reg) 10);
+   |                   ^^^^^^^
+   |
+   = help: only local labels of the form `<number>:` should be used in inline asm
+   = note: see the asm section of Rust By Example <https://doc.rust-lang.org/nightly/rust-by-example/unsafe/asm.html#labels> for more information
+
+error: avoid using named labels in inline assembly
+  --> $DIR/named-asm-labels.rs:134:15
+   |
+LL |         asm!("test_{}: nop", const 10);
+   |               ^^^^^^^
+   |
+   = help: only local labels of the form `<number>:` should be used in inline asm
+   = note: see the asm section of Rust By Example <https://doc.rust-lang.org/nightly/rust-by-example/unsafe/asm.html#labels> for more information
+
+error: avoid using named labels in inline assembly
+  --> $DIR/named-asm-labels.rs:135:15
+   |
+LL |         asm!("test_{}: nop", sym main);
+   |               ^^^^^^^
+   |
+   = help: only local labels of the form `<number>:` should be used in inline asm
+   = note: see the asm section of Rust By Example <https://doc.rust-lang.org/nightly/rust-by-example/unsafe/asm.html#labels> for more information
+
+error: avoid using named labels in inline assembly
+  --> $DIR/named-asm-labels.rs:136:15
+   |
+LL |         asm!("{}_test: nop", const 10);
+   |               ^^^^^^^
+   |
+   = help: only local labels of the form `<number>:` should be used in inline asm
+   = note: see the asm section of Rust By Example <https://doc.rust-lang.org/nightly/rust-by-example/unsafe/asm.html#labels> for more information
+
+error: avoid using named labels in inline assembly
+  --> $DIR/named-asm-labels.rs:137:15
+   |
+LL |         asm!("test_{}_test: nop", const 10);
+   |               ^^^^^^^^^^^^
+   |
+   = help: only local labels of the form `<number>:` should be used in inline asm
+   = note: see the asm section of Rust By Example <https://doc.rust-lang.org/nightly/rust-by-example/unsafe/asm.html#labels> for more information
+
+error: avoid using named labels in inline assembly
+  --> $DIR/named-asm-labels.rs:138:15
+   |
+LL |         asm!("{}: nop", const 10);
+   |               ^^
+   |
+   = help: only local labels of the form `<number>:` should be used in inline asm
+   = note: see the asm section of Rust By Example <https://doc.rust-lang.org/nightly/rust-by-example/unsafe/asm.html#labels> for more information
+
+error: avoid using named labels in inline assembly
+  --> $DIR/named-asm-labels.rs:140:15
+   |
+LL |         asm!("{uwu}: nop", uwu = const 10);
+   |               ^^^^^
+   |
+   = help: only local labels of the form `<number>:` should be used in inline asm
+   = note: see the asm section of Rust By Example <https://doc.rust-lang.org/nightly/rust-by-example/unsafe/asm.html#labels> for more information
+
+error: avoid using named labels in inline assembly
+  --> $DIR/named-asm-labels.rs:141:15
+   |
+LL |         asm!("{0}: nop", const 10);
+   |               ^^^
+   |
+   = help: only local labels of the form `<number>:` should be used in inline asm
+   = note: see the asm section of Rust By Example <https://doc.rust-lang.org/nightly/rust-by-example/unsafe/asm.html#labels> for more information
+
+error: avoid using named labels in inline assembly
+  --> $DIR/named-asm-labels.rs:142:15
+   |
+LL |         asm!("{1}: nop", "/* {0} */", const 10, const 20);
+   |               ^^^
+   |
+   = help: only local labels of the form `<number>:` should be used in inline asm
+   = note: see the asm section of Rust By Example <https://doc.rust-lang.org/nightly/rust-by-example/unsafe/asm.html#labels> for more information
+
+error: avoid using named labels in inline assembly
+  --> $DIR/named-asm-labels.rs:145:14
    |
 LL |         asm!(include_str!("named-asm-labels.s"));
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -254,21 +335,21 @@ LL |         asm!(include_str!("named-asm-labels.s"));
    = note: see the asm section of Rust By Example <https://doc.rust-lang.org/nightly/rust-by-example/unsafe/asm.html#labels> for more information
 
 warning: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:134:19
+  --> $DIR/named-asm-labels.rs:155:19
    |
 LL |             asm!("warned: nop");
    |                   ^^^^^^
    |
    = help: only local labels of the form `<number>:` should be used in inline asm
    = note: see the asm section of Rust By Example <https://doc.rust-lang.org/nightly/rust-by-example/unsafe/asm.html#labels> for more information
 note: the lint level is defined here
-  --> $DIR/named-asm-labels.rs:132:16
+  --> $DIR/named-asm-labels.rs:153:16
    |
 LL |         #[warn(named_asm_labels)]
    |                ^^^^^^^^^^^^^^^^
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:143:20
+  --> $DIR/named-asm-labels.rs:164:20
    |
 LL |     unsafe { asm!(".Lfoo: mov rax, {}; ret;", "nop", const 1, options(noreturn)) }
    |                    ^^^^^
@@ -277,7 +358,7 @@ LL |     unsafe { asm!(".Lfoo: mov rax, {}; ret;", "nop", const 1, options(noret
    = note: see the asm section of Rust By Example <https://doc.rust-lang.org/nightly/rust-by-example/unsafe/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:149:20
+  --> $DIR/named-asm-labels.rs:170:20
    |
 LL |     unsafe { asm!(".Lbar: mov rax, {}; ret;", "nop", const 1, options(noreturn)) }
    |                    ^^^^^
@@ -286,7 +367,7 @@ LL |     unsafe { asm!(".Lbar: mov rax, {}; ret;", "nop", const 1, options(noret
    = note: see the asm section of Rust By Example <https://doc.rust-lang.org/nightly/rust-by-example/unsafe/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:157:20
+  --> $DIR/named-asm-labels.rs:178:20
    |
 LL |     unsafe { asm!(".Laaa: nop; ret;", options(noreturn)) }
    |                    ^^^^^
@@ -295,7 +376,7 @@ LL |     unsafe { asm!(".Laaa: nop; ret;", options(noreturn)) }
    = note: see the asm section of Rust By Example <https://doc.rust-lang.org/nightly/rust-by-example/unsafe/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:167:24
+  --> $DIR/named-asm-labels.rs:188:24
    |
 LL |         unsafe { asm!(".Lbbb: nop; ret;", options(noreturn)) }
    |                        ^^^^^
@@ -304,7 +385,7 @@ LL |         unsafe { asm!(".Lbbb: nop; ret;", options(noreturn)) }
    = note: see the asm section of Rust By Example <https://doc.rust-lang.org/nightly/rust-by-example/unsafe/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:176:15
+  --> $DIR/named-asm-labels.rs:197:15
    |
 LL |         asm!("closure1: nop");
    |               ^^^^^^^^
@@ -313,7 +394,7 @@ LL |         asm!("closure1: nop");
    = note: see the asm section of Rust By Example <https://doc.rust-lang.org/nightly/rust-by-example/unsafe/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:180:15
+  --> $DIR/named-asm-labels.rs:201:15
    |
 LL |         asm!("closure2: nop");
    |               ^^^^^^^^
@@ -322,13 +403,13 @@ LL |         asm!("closure2: nop");
    = note: see the asm section of Rust By Example <https://doc.rust-lang.org/nightly/rust-by-example/unsafe/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:190:19
+  --> $DIR/named-asm-labels.rs:211:19
    |
 LL |             asm!("closure3: nop");
    |                   ^^^^^^^^
    |
    = help: only local labels of the form `<number>:` should be used in inline asm
    = note: see the asm section of Rust By Example <https://doc.rust-lang.org/nightly/rust-by-example/unsafe/asm.html#labels> for more information
 
-error: aborting due to 35 previous errors; 1 warning emitted
+error: aborting due to 44 previous errors; 1 warning emitted
 
