[glibc] nptl: __libc_cleanup_push/__libc_cleanup_pop require -fexceptions

[glibc] nptl: __libc_cleanup_push/__libc_cleanup_pop require -fexceptions

[Florian Weimer]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=e81402f246f53072aa799bfee101bf02d561a8c1

commit e81402f246f53072aa799bfee101bf02d561a8c1
Author: Florian Weimer <fweimer@redhat.com>
Date:   Tue Mar 2 10:49:03 2021 +0100

    nptl: __libc_cleanup_push/__libc_cleanup_pop require -fexceptions
    
    Do not define these macros if they do nothing in a particular
    compilation, otherwise they can easily be used accidentally, while
    not actually achieving anything.

Diff:
---
 sysdeps/nptl/libc-lockP.h | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/sysdeps/nptl/libc-lockP.h b/sysdeps/nptl/libc-lockP.h
index 0f74d783fe..4a0b96e6d9 100644
--- a/sysdeps/nptl/libc-lockP.h
+++ b/sysdeps/nptl/libc-lockP.h
@@ -271,6 +271,9 @@ extern void _pthread_cleanup_pop_restore (struct _pthread_cleanup_buffer *buffer
     } else if (DOIT)							      \
       _buffer.__routine (_buffer.__arg)
 
+/* __libc_cleanup_push and __libc_cleanup_pop depend on exception
+   handling and stack unwinding.  */
+#ifdef __EXCEPTIONS
 
 /* Normal cleanup handling, based on C cleanup attribute.  */
 __extern_inline void
@@ -280,17 +283,17 @@ __libc_cleanup_routine (struct __pthread_cleanup_frame *f)
     f->__cancel_routine (f->__cancel_arg);
 }
 
-#define __libc_cleanup_push(fct, arg) \
+# define __libc_cleanup_push(fct, arg) \
   do {									      \
     struct __pthread_cleanup_frame __clframe				      \
       __attribute__ ((__cleanup__ (__libc_cleanup_routine)))		      \
       = { .__cancel_routine = (fct), .__cancel_arg = (arg),		      \
 	  .__do_it = 1 };
 
-#define __libc_cleanup_pop(execute) \
+# define __libc_cleanup_pop(execute) \
     __clframe.__do_it = (execute);					      \
   } while (0)
-
+#endif /* __EXCEPTIONS */
 
 /* Create thread-specific key.  */
 #define __libc_key_create(KEY, DESTRUCTOR) \