fix: Revert "Makefile: Enable -Wimplicit-fallthrough for Clang" (v5.15)

[lttng-modules.git] / wrapper / compiler_attributes.h

diff --git a/wrapper/compiler_attributes.h b/wrapper/compiler_attributes.h
new file mode 100644 (file)
index 0000000..ae44903
--- /dev/null
+++ b/wrapper/compiler_attributes.h
@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
+ *
+ * wrapper/compiler_attributes.h
+ *
+ * Copyright (C) 2021 Michael Jeanson <mjeanson@efficios.com>
+ */
+
+#ifndef _LTTNG_WRAPPER_COMPILER_ATTRIBUTES_H
+#define _LTTNG_WRAPPER_COMPILER_ATTRIBUTES_H
+
+#include <lttng-kernel-version.h>
+
+#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,20,0))
+#include <linux/compiler_attributes.h>
+#endif
+
+#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,4,0))
+
+/*
+ * Use the kernel provided fallthrough attribute macro.
+ */
+#define lttng_fallthrough fallthrough
+
+#else /* LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,4,0) */
+
+/*
+ * Fallback to the comment for kernels pre 5.15 that don't build with
+ * '-Wimplicit-fallthrough=5'.
+ */
+#define lttng_fallthrough do {} while (0)  /* fallthrough */
+
+#endif /* LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,4,0) */
+
+#endif /* _LTTNG_WRAPPER_COMPILER_ATTRIBUTES_H */