From ddd97dc19a62a3be9495aecc5cd93c94d89237fe Mon Sep 17 00:00:00 2001
From: Trevor Gross <tmgross@umich.edu>
Date: Thu, 18 Jul 2024 03:25:03 -0500
Subject: [PATCH] Fix missing `extern "C"` for unsafe functions

`unsafe` functions were being matched in a different block that did not
include `extern $abi`. This means that some intrinsics were getting
generated with the Rust ABI rather than C.

Combine the last two blocks using an optional token matcher, which fixes
this problem and is cleaner.
---
 library/compiler-builtins/src/macros.rs | 33 +++----------------------
 1 file changed, 3 insertions(+), 30 deletions(-)

diff --git a/library/compiler-builtins/src/macros.rs b/library/compiler-builtins/src/macros.rs
index f537c1a968f0..fb14660af987 100644
--- a/library/compiler-builtins/src/macros.rs
+++ b/library/compiler-builtins/src/macros.rs
@@ -449,14 +449,14 @@ macro_rules! intrinsics {
     // input we were given.
     (
         $(#[$($attr:tt)*])*
-        pub extern $abi:tt fn $name:ident( $($argname:ident:  $ty:ty),* ) $(-> $ret:ty)? {
+        pub $(unsafe $(@ $empty:tt)?)? extern $abi:tt fn $name:ident( $($argname:ident:  $ty:ty),* ) $(-> $ret:ty)? {
             $($body:tt)*
         }
 
         $($rest:tt)*
     ) => (
         $(#[$($attr)*])*
-        pub extern $abi fn $name( $($argname: $ty),* ) $(-> $ret)? {
+        pub $(unsafe $($empty)?)? extern $abi fn $name( $($argname: $ty),* ) $(-> $ret)? {
             $($body)*
         }
 
@@ -465,34 +465,7 @@ macro_rules! intrinsics {
             $(#[$($attr)*])*
             #[no_mangle]
             #[cfg_attr(all(not(windows), not(target_vendor = "apple")), linkage = "weak")]
-            extern $abi fn $name( $($argname: $ty),* ) $(-> $ret)? {
-                super::$name($($argname),*)
-            }
-        }
-
-        intrinsics!($($rest)*);
-    );
-
-    // Same as the above for unsafe functions.
-    (
-        $(#[$($attr:tt)*])*
-        pub unsafe extern $abi:tt fn $name:ident( $($argname:ident:  $ty:ty),* ) $(-> $ret:ty)? {
-            $($body:tt)*
-        }
-
-        $($rest:tt)*
-    ) => (
-        $(#[$($attr)*])*
-        pub unsafe extern $abi fn $name( $($argname: $ty),* ) $(-> $ret)? {
-            $($body)*
-        }
-
-        #[cfg(not(feature = "mangled-names"))]
-        mod $name {
-            $(#[$($attr)*])*
-            #[no_mangle]
-            #[cfg_attr(all(not(windows), not(target_vendor = "apple")), linkage = "weak")]
-            unsafe fn $name( $($argname: $ty),* ) $(-> $ret)? {
+            $(unsafe $($empty)?)? extern $abi fn $name( $($argname: $ty),* ) $(-> $ret)? {
                 super::$name($($argname),*)
             }
         }