Break apart the gnu_inline attribute and use "artificial" if available.

In general it is bad practice to use the gnu_inline attribute but we
will need it in special cases like FORTIFY_SOURCE. In this specific
case it is also useful to have the "artificial" attribute:

"This attribute is useful for small inline wrappers which if possible
should appear during debugging as a unit, depending on the debug info
format it will either mean marking the function as artificial or using the
caller location for all instructions within the inlined body."

This attribute appears to be currently implemented only in GCC. Use it
only in conjuntion with gnu_inline in the cases where it is available,
which is similar in spirit in how it's used in glibc.

1 files changed, 15 insertions, 2 deletions

diff --git a/sys/sys/cdefs.h b/sys/sys/cdefs.h
index f46efcc..c7a7e4b 100644
--- a/sys/sys/cdefs.h
+++ b/sys/sys/cdefs.h
@@ -375,10 +375,8 @@
 #endif
 
 #if __GNUC_PREREQ__(4, 1)
-#define	__gnu_inline	__attribute__((__gnu_inline__))
 #define	__returns_twice	__attribute__((__returns_twice__))
 #else
-#define	__gnu_inline
 #define	__returns_twice
 #endif
 
@@ -538,6 +536,21 @@
 	    __attribute__((__format__ (__strftime__, fmtarg, firstvararg)))
 #endif
 
+/*
+ * FORTIFY_SOURCE, and perhaps other compiler-specific features, require
+ * the use of non-standard inlining.  In general we should try to avoid
+ * using these but GCC-compatible compilers tend to support the extensions
+ * well enough to use them in limited cases.
+ */ 
+#if __GNUC_PREREQ__(4, 1)
+#if __has_attribute(artificial) || __GNUC_PREREQ__(4, 3)
+#define	__gnu_inline	__attribute__((__gnu_inline__, __artificial__))
+#else
+#define	__gnu_inline	__attribute__((__gnu_inline__))
+#else
+#define	__gnu_inline
+#endif
+
 /* Compiler-dependent macros that rely on FreeBSD-specific extensions. */
 #if defined(__FreeBSD_cc_version) && __FreeBSD_cc_version >= 300001 && \
     defined(__GNUC__) && !defined(__INTEL_COMPILER)