Rollup merge of #88196 - asquared31415:named-asm-labels-refactor, r=Amanieu

Refactor `named_asm_labels` to a HIR lint

As discussed on #88169, the `named_asm_labels` lint could be moved to a HIR lint.  That allows future lints or custom plugins or clippy lints to more easily access the `asm!` macro's data and create better error messages with the lints.

2 files changed, 159 insertions, 32 deletions

diff --git a/src/test/ui/asm/named-asm-labels.rs b/src/test/ui/asm/named-asm-labels.rs
index 803501b40b6..9f487bd8061 100644
--- a/src/test/ui/asm/named-asm-labels.rs
+++ b/src/test/ui/asm/named-asm-labels.rs
@@ -1,6 +1,14 @@
 // only-x86_64
 
-#![feature(asm, global_asm)]
+// Tests that the use of named labels in the `asm!` macro are linted against
+// except for in `#[naked]` fns.
+// Using a named label is incorrect as per the RFC because for most cases
+// the compiler cannot ensure that inline asm is emitted exactly once per
+// codegen unit (except for naked fns) and so the label could be duplicated
+// which causes less readable LLVM errors and in the worst cases causes ICEs
+// or segfaults based on system dependent behavior and codegen flags.
+
+#![feature(asm, global_asm, naked_functions)]
 
 #[no_mangle]
 pub static FOO: usize = 42;
@@ -126,5 +134,61 @@ fn main() {
     }
 }
 
+// Trigger on naked fns too, even though they can't be inlined, reusing a
+// label or LTO can cause labels to break
+#[naked]
+pub extern "C" fn foo() -> i32 {
+    unsafe { asm!(".Lfoo: mov rax, {}; ret;", "nop", const 1, options(noreturn)) } //~ ERROR avoid using named labels
+}
+
+// Make sure that non-naked attributes *do* still let the lint happen
+#[no_mangle]
+pub extern "C" fn bar() {
+    unsafe { asm!(".Lbar: mov rax, {}; ret;", "nop", const 1, options(noreturn)) }
+    //~^ ERROR avoid using named labels
+}
+
+#[naked]
+pub extern "C" fn aaa() {
+    fn _local() {}
+
+    unsafe { asm!(".Laaa: nop; ret;", options(noreturn)) } //~ ERROR avoid using named labels
+}
+
+pub fn normal() {
+    fn _local1() {}
+
+    #[naked]
+    pub extern "C" fn bbb() {
+        fn _very_local() {}
+
+        unsafe { asm!(".Lbbb: nop; ret;", options(noreturn)) } //~ ERROR avoid using named labels
+    }
+
+    fn _local2() {}
+}
+
+// Make sure that the lint happens within closures
+fn closures() {
+    || unsafe {
+        asm!("closure1: nop"); //~ ERROR avoid using named labels
+    };
+
+    move || unsafe {
+        asm!("closure2: nop"); //~ ERROR avoid using named labels
+    };
+
+    || {
+        #[naked]
+        unsafe extern "C" fn _nested() {
+            asm!("ret;", options(noreturn));
+        }
+
+        unsafe {
+            asm!("closure3: nop"); //~ ERROR avoid using named labels
+        }
+    };
+}
+
 // Don't trigger on global asm
 global_asm!("aaaaaaaa: nop");
diff --git a/src/test/ui/asm/named-asm-labels.stderr b/src/test/ui/asm/named-asm-labels.stderr
index 3c4a4db75e0..396f0a19424 100644
--- a/src/test/ui/asm/named-asm-labels.stderr
+++ b/src/test/ui/asm/named-asm-labels.stderr
@@ -1,5 +1,5 @@
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:11:15
+  --> $DIR/named-asm-labels.rs:19:15
    |
 LL |         asm!("bar: nop");
    |               ^^^
@@ -9,7 +9,7 @@ LL |         asm!("bar: nop");
    = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:14:15
+  --> $DIR/named-asm-labels.rs:22:15
    |
 LL |         asm!("abcd:");
    |               ^^^^
@@ -18,7 +18,7 @@ LL |         asm!("abcd:");
    = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:17:15
+  --> $DIR/named-asm-labels.rs:25:15
    |
 LL |         asm!("foo: bar1: nop");
    |               ^^^  ^^^^
@@ -27,7 +27,7 @@ LL |         asm!("foo: bar1: nop");
    = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:21:15
+  --> $DIR/named-asm-labels.rs:29:15
    |
 LL |         asm!("foo1: nop", "nop");
    |               ^^^^
@@ -36,7 +36,7 @@ LL |         asm!("foo1: nop", "nop");
    = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:22:15
+  --> $DIR/named-asm-labels.rs:30:15
    |
 LL |         asm!("foo2: foo3: nop", "nop");
    |               ^^^^  ^^^^
@@ -45,7 +45,7 @@ LL |         asm!("foo2: foo3: nop", "nop");
    = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:24:22
+  --> $DIR/named-asm-labels.rs:32:22
    |
 LL |         asm!("nop", "foo4: nop");
    |                      ^^^^
@@ -54,7 +54,7 @@ LL |         asm!("nop", "foo4: nop");
    = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:25:15
+  --> $DIR/named-asm-labels.rs:33:15
    |
 LL |         asm!("foo5: nop", "foo6: nop");
    |               ^^^^
@@ -63,7 +63,7 @@ LL |         asm!("foo5: nop", "foo6: nop");
    = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:25:28
+  --> $DIR/named-asm-labels.rs:33:28
    |
 LL |         asm!("foo5: nop", "foo6: nop");
    |                            ^^^^
@@ -72,7 +72,7 @@ LL |         asm!("foo5: nop", "foo6: nop");
    = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:30:15
+  --> $DIR/named-asm-labels.rs:38:15
    |
 LL |         asm!("foo7: nop; foo8: nop");
    |               ^^^^       ^^^^
@@ -81,7 +81,7 @@ LL |         asm!("foo7: nop; foo8: nop");
    = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:32:15
+  --> $DIR/named-asm-labels.rs:40:15
    |
 LL |         asm!("foo9: nop; nop");
    |               ^^^^
@@ -90,7 +90,7 @@ LL |         asm!("foo9: nop; nop");
    = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:33:20
+  --> $DIR/named-asm-labels.rs:41:20
    |
 LL |         asm!("nop; foo10: nop");
    |                    ^^^^^
@@ -99,7 +99,7 @@ LL |         asm!("nop; foo10: nop");
    = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:36:15
+  --> $DIR/named-asm-labels.rs:44:15
    |
 LL |         asm!("bar2: nop\n bar3: nop");
    |               ^^^^        ^^^^
@@ -108,7 +108,7 @@ LL |         asm!("bar2: nop\n bar3: nop");
    = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:38:15
+  --> $DIR/named-asm-labels.rs:46:15
    |
 LL |         asm!("bar4: nop\n nop");
    |               ^^^^
@@ -117,7 +117,7 @@ LL |         asm!("bar4: nop\n nop");
    = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:39:21
+  --> $DIR/named-asm-labels.rs:47:21
    |
 LL |         asm!("nop\n bar5: nop");
    |                     ^^^^
@@ -126,7 +126,7 @@ LL |         asm!("nop\n bar5: nop");
    = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:40:21
+  --> $DIR/named-asm-labels.rs:48:21
    |
 LL |         asm!("nop\n bar6: bar7: nop");
    |                     ^^^^  ^^^^
@@ -135,7 +135,7 @@ LL |         asm!("nop\n bar6: bar7: nop");
    = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:46:13
+  --> $DIR/named-asm-labels.rs:54:13
    |
 LL |             blah2: nop
    |             ^^^^^
@@ -146,7 +146,7 @@ LL |             blah3: nop
    = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:55:19
+  --> $DIR/named-asm-labels.rs:63:19
    |
 LL |             nop ; blah4: nop
    |                   ^^^^^
@@ -155,7 +155,7 @@ LL |             nop ; blah4: nop
    = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:69:15
+  --> $DIR/named-asm-labels.rs:77:15
    |
 LL |         asm!("blah1: 2bar: nop");
    |               ^^^^^
@@ -164,7 +164,7 @@ LL |         asm!("blah1: 2bar: nop");
    = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:72:15
+  --> $DIR/named-asm-labels.rs:80:15
    |
 LL |         asm!("def: def: nop");
    |               ^^^
@@ -173,7 +173,7 @@ LL |         asm!("def: def: nop");
    = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:73:15
+  --> $DIR/named-asm-labels.rs:81:15
    |
 LL |         asm!("def: nop\ndef: nop");
    |               ^^^
@@ -182,7 +182,7 @@ LL |         asm!("def: nop\ndef: nop");
    = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:74:15
+  --> $DIR/named-asm-labels.rs:82:15
    |
 LL |         asm!("def: nop; def: nop");
    |               ^^^
@@ -191,7 +191,7 @@ LL |         asm!("def: nop; def: nop");
    = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:82:15
+  --> $DIR/named-asm-labels.rs:90:15
    |
 LL |         asm!("fooo\u{003A} nop");
    |               ^^^^^^^^^^^^^^^^
@@ -200,7 +200,7 @@ LL |         asm!("fooo\u{003A} nop");
    = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:83:15
+  --> $DIR/named-asm-labels.rs:91:15
    |
 LL |         asm!("foooo\x3A nop");
    |               ^^^^^^^^^^^^^
@@ -209,7 +209,7 @@ LL |         asm!("foooo\x3A nop");
    = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:86:15
+  --> $DIR/named-asm-labels.rs:94:15
    |
 LL |         asm!("fooooo:\u{000A} nop");
    |               ^^^^^^
@@ -218,7 +218,7 @@ LL |         asm!("fooooo:\u{000A} nop");
    = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:87:15
+  --> $DIR/named-asm-labels.rs:95:15
    |
 LL |         asm!("foooooo:\x0A nop");
    |               ^^^^^^^
@@ -227,7 +227,7 @@ LL |         asm!("foooooo:\x0A nop");
    = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:91:14
+  --> $DIR/named-asm-labels.rs:99:14
    |
 LL |         asm!("\x41\x42\x43\x3A\x20\x6E\x6F\x70");
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -236,7 +236,7 @@ LL |         asm!("\x41\x42\x43\x3A\x20\x6E\x6F\x70");
    = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:102:13
+  --> $DIR/named-asm-labels.rs:110:13
    |
 LL |             ab: nop // ab: does foo
    |             ^^
@@ -245,7 +245,7 @@ LL |             ab: nop // ab: does foo
    = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
 
 error: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:114:14
+  --> $DIR/named-asm-labels.rs:122:14
    |
 LL |         asm!(include_str!("named-asm-labels.s"));
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -254,18 +254,81 @@ LL |         asm!(include_str!("named-asm-labels.s"));
    = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
 
 warning: avoid using named labels in inline assembly
-  --> $DIR/named-asm-labels.rs:124:19
+  --> $DIR/named-asm-labels.rs:132:19
    |
 LL |             asm!("warned: nop");
    |                   ^^^^^^
    |
 note: the lint level is defined here
-  --> $DIR/named-asm-labels.rs:122:16
+  --> $DIR/named-asm-labels.rs:130:16
    |
 LL |         #[warn(named_asm_labels)]
    |                ^^^^^^^^^^^^^^^^
    = help: only local labels of the form `<number>:` should be used in inline asm
    = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
 
-error: aborting due to 28 previous errors; 1 warning emitted
+error: avoid using named labels in inline assembly
+  --> $DIR/named-asm-labels.rs:141:20
+   |
+LL |     unsafe { asm!(".Lfoo: mov rax, {}; ret;", "nop", const 1, options(noreturn)) }
+   |                    ^^^^^
+   |
+   = help: only local labels of the form `<number>:` should be used in inline asm
+   = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
+
+error: avoid using named labels in inline assembly
+  --> $DIR/named-asm-labels.rs:147:20
+   |
+LL |     unsafe { asm!(".Lbar: mov rax, {}; ret;", "nop", const 1, options(noreturn)) }
+   |                    ^^^^^
+   |
+   = help: only local labels of the form `<number>:` should be used in inline asm
+   = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
+
+error: avoid using named labels in inline assembly
+  --> $DIR/named-asm-labels.rs:155:20
+   |
+LL |     unsafe { asm!(".Laaa: nop; ret;", options(noreturn)) }
+   |                    ^^^^^
+   |
+   = help: only local labels of the form `<number>:` should be used in inline asm
+   = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
+
+error: avoid using named labels in inline assembly
+  --> $DIR/named-asm-labels.rs:165:24
+   |
+LL |         unsafe { asm!(".Lbbb: nop; ret;", options(noreturn)) }
+   |                        ^^^^^
+   |
+   = help: only local labels of the form `<number>:` should be used in inline asm
+   = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
+
+error: avoid using named labels in inline assembly
+  --> $DIR/named-asm-labels.rs:174:15
+   |
+LL |         asm!("closure1: nop");
+   |               ^^^^^^^^
+   |
+   = help: only local labels of the form `<number>:` should be used in inline asm
+   = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
+
+error: avoid using named labels in inline assembly
+  --> $DIR/named-asm-labels.rs:178:15
+   |
+LL |         asm!("closure2: nop");
+   |               ^^^^^^^^
+   |
+   = help: only local labels of the form `<number>:` should be used in inline asm
+   = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
+
+error: avoid using named labels in inline assembly
+  --> $DIR/named-asm-labels.rs:188:19
+   |
+LL |             asm!("closure3: nop");
+   |                   ^^^^^^^^
+   |
+   = help: only local labels of the form `<number>:` should be used in inline asm
+   = note: see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information
+
+error: aborting due to 35 previous errors; 1 warning emitted