SEC: Add LM3S backend for entropy pulling.

[bertos.git] / bertos / cfg / compiler.h

diff --git a/bertos/cfg/compiler.h b/bertos/cfg/compiler.h
index 907b23e6d1749cf496a675937e580898d1ee0f73..843af838c502621f473713c8dff6a945357b28e6 100644 (file)
--- a/bertos/cfg/compiler.h
+++ b/bertos/cfg/compiler.h
@@ -531,7 +531,22 @@ typedef unsigned char sigmask_t; /**< Type for signal masks. */
         *
         * \note This macro is non-standard, but implements a very common idiom
         */
-       #define countof(a)  (sizeof(a) / sizeof(*(a)))
+       #if defined(__GNUC__) && !defined(__cplusplus)
+               /*
+                * Perform a compile time type checking: countof() can only
+                * work with static arrays, so throw a compile time error if a
+                * pointer is passed as argument.
+                *
+                * NOTE: the construct __builtin_types_compatible_p() is only
+                * available for C.
+                */
+               #define countof(a) (sizeof(a) / sizeof(*(a)) +          \
+                               STATIC_ASSERT_EXPR(                     \
+                                       !__builtin_types_compatible_p(  \
+                                               typeof(a), typeof(&a[0]))))
+       #else
+               #define countof(a)  (sizeof(a) / sizeof(*(a)))
+       #endif
 #endif
 #ifndef alignof
        /**
@@ -565,6 +580,13 @@ typedef unsigned char sigmask_t; /**< Type for signal masks. */
 #define STATIC_ASSERT(condition)  \
        UNUSED_VAR(extern char, STATIC_ASSERTION_FAILED__[(condition) ? 1 : -1])
 
+/**
+ * Issue a compilation error if \a __cond is false (this can be used inside an
+ * expression).
+ */
+#define STATIC_ASSERT_EXPR(__cond) \
+       (sizeof(struct { int STATIC_ASSERTION_FAILED__:!!(__cond); }) * 0)
+
 #ifndef ASSERT_TYPE_EQUAL
        /** Ensure two variables have the same type. */
        #define ASSERT_TYPE_EQUAL(var1, var2)  \