abort() is used in gcc_assert() and gcc_unreachable() which is used by target
libraries such as libgcov.a. This patch changes the abort() definition under
certain conditions. If inhibit_libc is defined and abort is not already
defined, then abort() is defined to __builtin_trap().
The inhibit_libc define is usually defined if GCC is built for targets running
in embedded systems which may optionally use a C standard library. If
inhibit_libc is defined, then there may be still a full featured abort()
available. abort() is a heavy weight function which depends on signals and
file streams. For statically linked applications, this means that a dependency
on gcc_assert() pulls in the support for signals and file streams. This could
prevent using gcov to test low end targets for example. Using __builtin_trap()
avoids these dependencies if the target implements a "trap" instruction. The
application or operating system could use a trap handler to react to failed GCC
runtime checks which caused a trap.
gcc/
* tsystem.h (abort): Define abort() if inhibit_libc is defined and it
is not already defined.
#endif
#ifndef abort
-extern void abort (void) __attribute__ ((__noreturn__));
+#define abort() __builtin_trap ()
#endif
#ifndef strlen