gcov: use no-op functions if not enabled

Instead of wrapping every gcov function call in an ifdef.

Note: The usage of `((void)0)` is based on section 7.2 of the C99
standard (N1256)[1] [2]:

> 7.2 Diagnostics <assert.h>
>
> 1 The header <assert.h> defines the assert macro and refers to another
> macro,
>
>     NDEBUG
>
> which is not defined by <assert.h>. If NDEBUG is defined as a macro
> name at the point in the source file where <assert.h> is included, the
> assert macro is defined simply as
>
>     #define assert(ignore) ((void)0)

See also assert.h(0p) from POSIX.1-2017[3].

Note: This is a continuation of commit b408b20c7 ("gcov: fix build
failure with gcc 11.1.0") / PR #4373.

[1] http://www.open-std.org/JTC1/SC22/WG14/www/docs/n1256.pdf
[2] https://port70.net/~nsz/c/c99/n1256.html#7.2
[3] https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/assert.h.html

1 files changed, 6 insertions, 0 deletions

diff --git a/src/include/gcov_wrapper.h b/src/include/gcov_wrapper.h
index 2f409309d..4aafb8e18 100644
--- a/src/include/gcov_wrapper.h
+++ b/src/include/gcov_wrapper.h
@@ -21,6 +21,7 @@
 #ifndef GCOV_WRAPPER_H
 #define GCOV_WRAPPER_H
 
+#ifdef HAS_GCOV
 #include <gcov.h>
 
 /*
@@ -36,5 +37,10 @@ static void __gcov_flush(void) {
        __gcov_reset();
 }
 #endif
+#else
+#define __gcov_dump() ((void)0)
+#define __gcov_reset() ((void)0)
+#define __gcov_flush() ((void)0)
+#endif /* HAS_GCOV */
 
 #endif /* GCOV_WRAPPER_H */