gcc_assert() and inhibit_libc

[Sebastian Huber]

On 22/07/2021 14:15, Richard Biener wrote:
> On Wed, Jul 21, 2021 at 2:45 PM Sebastian Huber
> <sebastian.huber@embedded-brains.de>  wrote:
>> Hello,
>>
>> while testing this patch
>>
>> https://www.google.com/search?client=firefox-b-e&q=gcc+enable_runtime_checking
>>
>> I noticed that __gcov_info_to_gcda() uses abort(). This is due to (from
>> tsystem.h):
>>
>> #ifdef ENABLE_RUNTIME_CHECKING
>> #define gcc_assert(EXPR) ((void)(!(EXPR) ? abort (), 0 : 0))
>> #else
>> /* Include EXPR, so that unused variable warnings do not occur.  */
>> #define gcc_assert(EXPR) ((void)(0 && (EXPR)))
>> #endif
>>
>> In tsystem.h there is this if inhibit_libc is defined:
>>
>> #ifndef abort
>> extern void abort (void) __attribute__ ((__noreturn__));
>> #endif
>>
>> Who is supposed to define abort here optionally? Can this be defined for
>> example by a target configuration header like gcc/config/rtems.h?
> I suppose for inhibit_libc we could use __builtin_trap () (but that might
> expand to abort() on some targets)

In case of RTEMS, the application and the operating system is statically 
linked into one executable. The more features an application uses the 
bigger will be the executable. The abort() function pulls in a lot of 
stuff since it uses signals and may attempt to close all open streams. 
It would be nice if the gcc_assert() could be customized by the target 
configuration. For RTEMS we could use the Newlib defined __assert_func() 
from <assert.h>:

# define assert(__e) ((__e) ? (void)0 : __assert_func (__FILE__, __LINE__, \
						       __ASSERT_FUNC, #__e))


void __assert_func (const char *, int, const char *, const char *)
	    _ATTRIBUTE ((__noreturn__));


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