| Message ID | m1107c$q5c$1@ger.gmane.org |
|---|---|
| State | New |
| Headers | show |
ping On 10/07/2014 05:18 PM, Stefan Liebler wrote: > Hi, > > On s390-32|64 i get the following build warning > "sysdeps/s390/s390-64/backtrace.c:133:24: warning: the comparison will > always evaluate as ‘false’ for the address of ‘_Unwind_Backtrace’ will > never be NULL [-Waddress]" for the non SHARED case. > In SHARED case, the _Unwind_Backtrace function is loaded via dlsym() and > thus needs to be NULL-checked (if (unwind_backtrace == NULL)) in order > to fallback to __backchain_backtrace() function. > > In non SHARED case, the #define unwind_backtrace _Unwind_Backtrace was > introduced with "* sysdeps/s390/s390-32/backtrace.c (init): Guard with > #ifdef SHARED." (Roland McGrath <roland@gnu.org> 2004-06-11 22:12:55) > and the NULL-check will never be false for _Unwind_Backtrace() function. > Thus this NULL-check is now only evaluated in SHARED-case. > > The __backchain_backtrace function is only used in the SHARED-case, > if the unwind-function is not found. Thus it is now only compiled in the > SHARED-case, to avoid the warning: warning: ‘__backchain_backtrace’ > defined but not used [-Wunused-function]. > > On s390-32, this function is declared as static, but not on s390-64. > These functions were introduced in the same patch > "Update." (Ulrich Drepper <drepper@redhat.com> 2003-12-06 01:20:16) > and the Changelog from Martin Schwidefsky says: > * sysdeps/s390/s390-32/backtrace.c (trace_arg): New structure. > (unwind_backtrace, unwind_getip): New variables. > (init, __backchain_backtrace, backtrace_helper): New functions. > (__backtrace): Use unwind info for backtrace instead of backchain > walking if the unwind functions can be found. > * sysdeps/s390/s390-64/backtrace.c: Likewise. > > On s390-64 it isn´t exported in the shared library, thus on s390-64 it > is now declared as static too! > > Bye Stefan > > --- > 2014-10-07 Stefan Liebler <stli@linux.vnet.ibm.com> > > * sysdeps/s390/s390-32/backtrace.c (__backtrace): > Check for unwind_backtrace == NULL only in SHARED case. > (__backchain_backtrace): Compile only in SHARED case. > * sysdeps/s390/s390-64/backtrace.c (__backtrace): > Likewise. > (__backchain_backtrace): Declare as static.
On 10/07/2014 05:18 PM, Stefan Liebler wrote: > 2014-10-07 Stefan Liebler <stli@linux.vnet.ibm.com> > > * sysdeps/s390/s390-32/backtrace.c (__backtrace): > Check for unwind_backtrace == NULL only in SHARED case. > (__backchain_backtrace): Compile only in SHARED case. > * sysdeps/s390/s390-64/backtrace.c (__backtrace): > Likewise. > (__backchain_backtrace): Declare as static. > Applied. Thanks! -Andreas-
diff --git a/sysdeps/s390/s390-32/backtrace.c b/sysdeps/s390/s390-32/backtrace.c index 3ade10c..e3122cf 100644 --- a/sysdeps/s390/s390-32/backtrace.c +++ b/sysdeps/s390/s390-32/backtrace.c @@ -77,10 +77,6 @@ init (void) if (unwind_getip == NULL) unwind_backtrace = NULL; } -#else -# define unwind_backtrace _Unwind_Backtrace -# define unwind_getip _Unwind_GetIP -#endif static int __backchain_backtrace (void **array, int size) @@ -107,6 +103,10 @@ __backchain_backtrace (void **array, int size) return cnt; } +#else +# define unwind_backtrace _Unwind_Backtrace +# define unwind_getip _Unwind_GetIP +#endif static _Unwind_Reason_Code backtrace_helper (struct _Unwind_Context *ctx, void *a) @@ -130,9 +130,10 @@ __backtrace (void **array, int size) __libc_once_define (static, once); __libc_once (once, init); -#endif + if (unwind_backtrace == NULL) return __backchain_backtrace (array, size); +#endif if (size >= 1) unwind_backtrace (backtrace_helper, &arg); diff --git a/sysdeps/s390/s390-64/backtrace.c b/sysdeps/s390/s390-64/backtrace.c index 39a15e0..74b5581 100644 --- a/sysdeps/s390/s390-64/backtrace.c +++ b/sysdeps/s390/s390-64/backtrace.c @@ -76,12 +76,8 @@ init (void) if (unwind_getip == NULL) unwind_backtrace = NULL; } -#else -# define unwind_backtrace _Unwind_Backtrace -# define unwind_getip _Unwind_GetIP -#endif -int +static int __backchain_backtrace (void **array, int size) { /* We assume that all the code is generated with frame pointers set. */ @@ -106,6 +102,10 @@ __backchain_backtrace (void **array, int size) return cnt; } +#else +# define unwind_backtrace _Unwind_Backtrace +# define unwind_getip _Unwind_GetIP +#endif static _Unwind_Reason_Code backtrace_helper (struct _Unwind_Context *ctx, void *a) @@ -129,9 +129,10 @@ __backtrace (void **array, int size) __libc_once_define (static, once); __libc_once (once, init); -#endif + if (unwind_backtrace == NULL) return __backchain_backtrace (array, size); +#endif if (size >= 1) unwind_backtrace (backtrace_helper, &arg);