Mark hooked functions as visibility(("protected")).

[coloredstderr/coloredstderr.git] / src / compiler.h

diff --git a/src/compiler.h b/src/compiler.h
index 3d92f2fac5f1e05eef2a93f4191e1dd489465df7..d1c12dc05719262b64443366e0fb817138d7da42 100644 (file)
--- a/src/compiler.h
+++ b/src/compiler.h
@@ -20,6 +20,27 @@
 #ifndef COMPILER_H
 #define COMPILER_H 1
 
+#ifdef HAVE___ATTRIBUTE__
+/* Prevent/force inlining. Used to improve performance. */
+# define noinline      __attribute__((noinline))
+# define always_inline __attribute__((always_inline))
+/* Unused parameter. */
+# define unused        __attribute__((unused))
+/* Mark the function protected, which means it can't be overwritten by other
+ * modules (libraries), e.g. with LD_PRELOAD); otherwise same as the default
+ * visibility. This causes the compiler not use the PLT (and no relocations)
+ * for local calls from inside this module; but the symbols are still
+ * exported. This is faster and in this case prevents useless lookups as we
+ * hook those functions and nobody else should modify them. Not strictly
+ * necessary, but nice to have. */
+# define visibility_protected __attribute__((visibility("protected")))
+#else
+# define noinline
+# define always_inline
+# define unused
+# define visibility_protected
+#endif
+
 /* Branch prediction information for the compiler. */
 #ifdef HAVE___BUILTIN_EXPECT
 # define likely(x)   __builtin_expect(!!(x), 1)