commit 91e75075aec3bacf06b9e3ed91b1de1ec9dd6a67
author Stephanos Ioannidis <root@stephanos.io> Mon Sep 09 20:59:45 2019 +0900
committer Carles Cufí <carles.cufi@nordicsemi.no> Mon Sep 09 21:40:54 2019 +0200
tree b4686b3d05a3c0d25719d93fff2a765b0f5cd21e
parent 5a53e219669210ded29438d8cd42f2c796a640d9

toolchain: Add global check for endianness preprocessor definitions.

This commit adds a global check for __BYTE_ORDER__,
__ORDER_LITTLE_ENDIAN__ and __ORDER_BIG_ENDIAN__ preprocessor
definitions that are used throughout the Zephyr codebase.

These preprocessor definitions being not defined can easily
go unnoticed and cause unexpected behaviours, as detailed in
PR #18922.

Signed-off-by: Stephanos Ioannidis <root@stephanos.io>

include/toolchain.h

diff --git a/include/toolchain.h b/include/toolchain.h
index 88cedb0..adc8c2c 100644
--- a/include/toolchain.h
+++ b/include/toolchain.h
@@ -41,4 +41,18 @@
 #include <toolchain/other.h>
 #endif
 
+/*
+ * Ensure that __BYTE_ORDER__ and related preprocessor definitions are defined,
+ * as these are often used without checking for definition and doing so can
+ * cause unexpected behaviours.
+ */
+#ifndef _LINKER
+#if !defined(__BYTE_ORDER__) || !defined(__ORDER_BIG_ENDIAN__) || \
+    !defined(__ORDER_LITTLE_ENDIAN__)
+
+#error "__BYTE_ORDER__ is not defined"
+
+#endif
+#endif /* !_LINKER */
+
 #endif /* ZEPHYR_INCLUDE_TOOLCHAIN_H_ */