[PATCH] eal: add nonnull and access function attributes

[Morten Brørup]

Add "nonnull" function attribute to help the compiler detect a NULL
pointer being passed to a function not accepting NULL pointers as an
argument at build time.

Add "access" function attribute to tell the optimizer how a function
accesses its pointer arguments.

Add these attributes to the rte_memcpy() function, as the first in
hopefully many to come.

Signed-off-by: Morten Brørup <mb at smartsharesystems.com>
---
 lib/eal/arm/include/rte_memcpy_32.h  |  6 ++++++
 lib/eal/arm/include/rte_memcpy_64.h  |  6 ++++++
 lib/eal/include/generic/rte_memcpy.h |  5 +++++
 lib/eal/include/rte_common.h         | 26 ++++++++++++++++++++++++++
 lib/eal/ppc/include/rte_memcpy.h     |  3 +++
 lib/eal/x86/include/rte_memcpy.h     |  6 ++++++
 6 files changed, 52 insertions(+)

diff --git a/lib/eal/arm/include/rte_memcpy_32.h b/lib/eal/arm/include/rte_memcpy_32.h
index fb3245b59c..ba4f050a5d 100644
--- a/lib/eal/arm/include/rte_memcpy_32.h
+++ b/lib/eal/arm/include/rte_memcpy_32.h
@@ -125,6 +125,9 @@ rte_mov256(uint8_t *dst, const uint8_t *src)
 	memcpy((dst), (src), (n)) :          \
 	rte_memcpy_func((dst), (src), (n)); })
 
+__rte_nonnull(1, 2)
+__rte_access(write_only, 1, 3)
+__rte_access(read_only, 2, 3)
 static inline void *
 rte_memcpy_func(void *dst, const void *src, size_t n)
 {
@@ -290,6 +293,9 @@ rte_mov256(uint8_t *dst, const uint8_t *src)
 	memcpy(dst, src, 256);
 }
 
+__rte_nonnull(1, 2)
+__rte_access(write_only, 1, 3)
+__rte_access(read_only, 2, 3)
 static inline void *
 rte_memcpy(void *dst, const void *src, size_t n)
 {
diff --git a/lib/eal/arm/include/rte_memcpy_64.h b/lib/eal/arm/include/rte_memcpy_64.h
index 85ad587bd3..5403e30db5 100644
--- a/lib/eal/arm/include/rte_memcpy_64.h
+++ b/lib/eal/arm/include/rte_memcpy_64.h
@@ -282,6 +282,9 @@ void rte_memcpy_ge64(uint8_t *dst, const uint8_t *src, size_t n)
 }
 
 #if RTE_CACHE_LINE_SIZE >= 128
+__rte_nonnull(1, 2)
+__rte_access(write_only, 1, 3)
+__rte_access(read_only, 2, 3)
 static __rte_always_inline
 void *rte_memcpy(void *dst, const void *src, size_t n)
 {
@@ -303,6 +306,9 @@ void *rte_memcpy(void *dst, const void *src, size_t n)
 }
 
 #else
+__rte_nonnull(1, 2)
+__rte_access(write_only, 1, 3)
+__rte_access(read_only, 2, 3)
 static __rte_always_inline
 void *rte_memcpy(void *dst, const void *src, size_t n)
 {
diff --git a/lib/eal/include/generic/rte_memcpy.h b/lib/eal/include/generic/rte_memcpy.h
index e7f0f8eaa9..86fd20884c 100644
--- a/lib/eal/include/generic/rte_memcpy.h
+++ b/lib/eal/include/generic/rte_memcpy.h
@@ -11,6 +11,8 @@
  * Functions for vectorised implementation of memcpy().
  */
 
+#include <rte_common.h>
+
 /**
  * Copy 16 bytes from one location to another using optimised
  * instructions. The locations should not overlap.
@@ -108,6 +110,9 @@ rte_mov256(uint8_t *dst, const uint8_t *src);
  * @return
  *   Pointer to the destination data.
  */
+__rte_nonnull(1, 2)
+__rte_access(write_only, 1, 3)
+__rte_access(read_only, 2, 3)
 static void *
 rte_memcpy(void *dst, const void *src, size_t n);
 
diff --git a/lib/eal/include/rte_common.h b/lib/eal/include/rte_common.h
index 15765b408d..c2bd6074b1 100644
--- a/lib/eal/include/rte_common.h
+++ b/lib/eal/include/rte_common.h
@@ -149,6 +149,32 @@ typedef uint16_t unaligned_uint16_t;
 	__attribute__((format(printf, format_index, first_arg)))
 #endif
 
+/**
+ * Check pointer arguments at compile-time.
+ *
+ * @param ...
+ *    Comma separated list of parameter indexes of pointer arguments.
+ */
+#define __rte_nonnull(...) \
+	__attribute__((nonnull(__VA_ARGS__)))
+
+/**
+ * Tells compiler about the access mode of a pointer argument.
+ *
+ * @param access_mode
+ *    Access mode: read_only, read_write, write_only, or none.
+ * @param ref_index
+ *    Parameter index of pointer argument.
+ * @param size_index (optional)
+ *    Parameter index of size argument.
+ */
+#if defined(RTE_CC_IS_GNU) && (GCC_VERSION >= 100400)
+#define __rte_access(access_mode, ...) \
+	__attribute__((access(access_mode, __VA_ARGS__)))
+#else
+#define __rte_access(access_mode, ...)
+#endif
+
 /**
  * Tells compiler that the function returns a value that points to
  * memory, where the size is given by the one or two arguments.
diff --git a/lib/eal/ppc/include/rte_memcpy.h b/lib/eal/ppc/include/rte_memcpy.h
index 6f388c0234..d2c3234d5d 100644
--- a/lib/eal/ppc/include/rte_memcpy.h
+++ b/lib/eal/ppc/include/rte_memcpy.h
@@ -84,6 +84,9 @@ rte_mov256(uint8_t *dst, const uint8_t *src)
 	memcpy((dst), (src), (n)) :          \
 	rte_memcpy_func((dst), (src), (n)); })
 
+__rte_nonnull(1, 2)
+__rte_access(write_only, 1, 3)
+__rte_access(read_only, 2, 3)
 static inline void *
 rte_memcpy_func(void *dst, const void *src, size_t n)
 {
diff --git a/lib/eal/x86/include/rte_memcpy.h b/lib/eal/x86/include/rte_memcpy.h
index d4d7a5cfc8..397461115b 100644
--- a/lib/eal/x86/include/rte_memcpy.h
+++ b/lib/eal/x86/include/rte_memcpy.h
@@ -42,6 +42,9 @@ extern "C" {
  * @return
  *   Pointer to the destination data.
  */
+__rte_nonnull(1, 2)
+__rte_access(write_only, 1, 3)
+__rte_access(read_only, 2, 3)
 static __rte_always_inline void *
 rte_memcpy(void *dst, const void *src, size_t n);
 
@@ -859,6 +862,9 @@ rte_memcpy_aligned(void *dst, const void *src, size_t n)
 	return ret;
 }
 
+__rte_nonnull(1, 2)
+__rte_access(write_only, 1, 3)
+__rte_access(read_only, 2, 3)
 static __rte_always_inline void *
 rte_memcpy(void *dst, const void *src, size_t n)
 {
-- 
2.17.1