Hi,
On Tue, Aug 17, 2021 at 10:43 AM Sebastian Huber <
sebastian.hu...@embedded-brains.de> wrote:
> 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.
>
This causes a build failure on arm:
In file included from /libgcc/config/arm/unwind-arm.c:144:
/libgcc/unwind-arm-common.inc:55:24: error: macro "abort" passed 1
arguments, but takes just 0
55 | extern void abort (void);
This small patch should fix it:
diff --git a/libgcc/unwind-arm-common.inc b/libgcc/unwind-arm-common.inc
index c9b70c10d4f..77ec02ec811 100644
--- a/libgcc/unwind-arm-common.inc
+++ b/libgcc/unwind-arm-common.inc
@@ -50,10 +50,6 @@
#define ARM_SIGCONTEXT_R0 0xc
#endif
-/* We add a prototype for abort here to avoid creating a dependency on
- target headers. */
-extern void abort (void);
-
/* Definitions for C++ runtime support routines. We make these weak
declarations to avoid pulling in libsupc++ unnecessarily. */
typedef unsigned char bool;
Christophe
> ---
> gcc/tsystem.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/gcc/tsystem.h b/gcc/tsystem.h
> index e1e6a96a4f48..5c72c69ff3ed 100644
> --- a/gcc/tsystem.h
> +++ b/gcc/tsystem.h
> @@ -59,7 +59,7 @@ extern int atexit (void (*)(void));
> #endif
>
> #ifndef abort
> -extern void abort (void) __attribute__ ((__noreturn__));
> +#define abort() __builtin_trap ()
> #endif
>
> #ifndef strlen
> --
> 2.26.2
>
>
