naked_asm: emit a label starting with `func_end`

The `cargo asm` tool pattern matches on such labels to figure out where functions end: normal functions generated by LLVM always do have such a label. We don't guarantee that naked functions emit such a label, but having `cargo asm` work is convenient

1 files changed, 6 insertions, 0 deletions

diff --git a/compiler/rustc_codegen_ssa/src/mir/naked_asm.rs b/compiler/rustc_codegen_ssa/src/mir/naked_asm.rs
index 31784cabf4a..e7239ebfecf 100644
--- a/compiler/rustc_codegen_ssa/src/mir/naked_asm.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/naked_asm.rs
@@ -228,6 +228,9 @@ fn prefix_and_suffix<'tcx>(
             writeln!(begin, "{asm_name}:").unwrap();
 
             writeln!(end).unwrap();
+            // emit a label starting with `func_end` for `cargo asm` and other tooling that might
+            // pattern match on assembly generated by LLVM.
+            writeln!(end, ".Lfunc_end_{asm_name}:").unwrap();
             writeln!(end, ".size {asm_name}, . - {asm_name}").unwrap();
             writeln!(end, ".popsection").unwrap();
             if !arch_suffix.is_empty() {
@@ -246,6 +249,7 @@ fn prefix_and_suffix<'tcx>(
             writeln!(begin, "{asm_name}:").unwrap();
 
             writeln!(end).unwrap();
+            writeln!(end, ".Lfunc_end_{asm_name}:").unwrap();
             writeln!(end, ".popsection").unwrap();
             if !arch_suffix.is_empty() {
                 writeln!(end, "{}", arch_suffix).unwrap();
@@ -263,6 +267,7 @@ fn prefix_and_suffix<'tcx>(
             writeln!(begin, "{asm_name}:").unwrap();
 
             writeln!(end).unwrap();
+            writeln!(end, ".Lfunc_end_{asm_name}:").unwrap();
             writeln!(end, ".popsection").unwrap();
             if !arch_suffix.is_empty() {
                 writeln!(end, "{}", arch_suffix).unwrap();
@@ -287,6 +292,7 @@ fn prefix_and_suffix<'tcx>(
             writeln!(end).unwrap();
             // .size is ignored for function symbols, so we can skip it
             writeln!(end, "end_function").unwrap();
+            writeln!(end, ".Lfunc_end_{asm_name}:").unwrap();
         }
         BinaryFormat::Xcoff => {
             // the LLVM XCOFFAsmParser is extremely incomplete and does not implement many of the