It was a common pattern to have "GCC diagnostic ignored" pragmas
sprinkled over the code and only activate these pragmas for certain
compilers (gcc and clang). Clang supports GCC's pragma for
compatibility with existing source code, so #pragma GCC diagnostic
and #pragma clang diagnostic are synonyms for Clang
(https://clang.llvm.org/docs/UsersManual.html).
Now that effort is being made to make the code compatible with MSVC
these expressions would become more complex. It makes sense to hide
this complexity behind macros. This makes maintenance easier as these
macros are defined in a single place. As a plus the code becomes
more readable as well.
Signed-off-by: Andre Muezerie <andre...@linux.microsoft.com>
---
lib/eal/include/rte_common.h | 46 ++++++++++++++++++++++++++++++++++++
1 file changed, 46 insertions(+)
diff --git a/lib/eal/include/rte_common.h b/lib/eal/include/rte_common.h
index 40592f71b1..4b87a0a352 100644
--- a/lib/eal/include/rte_common.h
+++ b/lib/eal/include/rte_common.h
@@ -156,6 +156,52 @@ typedef uint16_t unaligned_uint16_t;
#define RTE_DEPRECATED(x)
#endif
+/**
+ * Macros to cause the compiler to remember the state of the diagnostics as of
+ * each push, and restore to that point at each pop.
+ */
+#if !defined(__INTEL_COMPILER) && !defined(RTE_TOOLCHAIN_MSVC)
+#define __rte_diagnostic_push _Pragma("GCC diagnostic push")
+#define __rte_diagnostic_pop _Pragma("GCC diagnostic pop")
+#else
+#define __rte_diagnostic_push
+#define __rte_diagnostic_pop
+#endif
+
+/**
+ * Macro to disable compiler warnings about removing a type
+ * qualifier from the target type.
+ */
+#if !defined(__INTEL_COMPILER) && !defined(RTE_TOOLCHAIN_MSVC)
+#define __rte_diagnostic_ignored_wcast_qual \
+ _Pragma("GCC diagnostic ignored \"-Wcast-qual\"")
+#else
+#define __rte_diagnostic_ignored_wcast_qual
+#endif
+
+/**
+ * Workaround to discard qualifiers (such as const, volatile, restrict) from a
pointer,
+ * without the compiler emitting a warning.
+ */
+#define RTE_PTR_UNQUAL(X) ((void *)(uintptr_t)(X))
+
+/**
+ * Workaround to discard qualifiers (such as const, volatile, restrict) from a
pointer
+ * and cast it to a specific type, without the compiler emitting a warning.
+ *
+ * @warning
+ * Although this macro can be abused for casting a pointer to point to a
different type,
+ * alignment may be incorrect when casting to point to a larger type. E.g.:
+ * struct s {
+ * uint16_t a;
+ * uint8_t b;
+ * uint8_t c;
+ * uint8_t d;
+ * } v;
+ * uint16_t * p = RTE_CAST_PTR(uint16_t *, &v.c); // "p" is not 16 bit
aligned!
+ */
+#define RTE_CAST_PTR(type, ptr) ((type)(uintptr_t)(ptr))
+
/**
* Mark a function or variable to a weak reference.
*/
--
2.47.2.vfs.0.1
