[PATCH v3 3/5] eal: make unaligned really unaligned

[Stephen Hemminger]

The common tests that expected unaligned to really have no
guaranteed alignment would fail with UBSAN. The root cause
was the definition of unaligned still implied alignment on x86.

Signed-off-by: Stephen Hemminger <stephen at networkplumber.org>
---
 doc/guides/rel_notes/release_26_11.rst |  6 ++++++
 lib/eal/include/rte_common.h           | 13 ++++++++-----
 2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/doc/guides/rel_notes/release_26_11.rst b/doc/guides/rel_notes/release_26_11.rst
index 4cadfc1918..4b219cbc97 100644
--- a/doc/guides/rel_notes/release_26_11.rst
+++ b/doc/guides/rel_notes/release_26_11.rst
@@ -109,6 +109,12 @@ API Changes
     compile with an integer argument, but this is deprecated usage: existing code
     should use ``RTE_ALIGN``, ``RTE_ALIGN_CEIL`` or ``RTE_ALIGN_FLOOR`` instead.
 
+* **eal: Unaligned integer types are now really unaligned.**
+
+  ``unaligned_uint16_t``, ``unaligned_uint32_t`` and ``unaligned_uint64_t``
+  are now declared with an alignment of 1 on all architectures.
+  The compiler may generate narrower loads and stores than before.
+
 
 ABI Changes
 -----------
diff --git a/lib/eal/include/rte_common.h b/lib/eal/include/rte_common.h
index ed037be399..bb7dfb8ba5 100644
--- a/lib/eal/include/rte_common.h
+++ b/lib/eal/include/rte_common.h
@@ -149,14 +149,17 @@ extern "C" {
 #define __rte_aligned(a) __attribute__((__aligned__(a)))
 #endif
 
-#ifdef RTE_ARCH_STRICT_ALIGN
+/**
+ * Integer types with no alignment requirement.
+ */
+#ifdef RTE_TOOLCHAIN_MSVC
+typedef __unaligned uint64_t unaligned_uint64_t;
+typedef __unaligned uint32_t unaligned_uint32_t;
+typedef __unaligned uint16_t unaligned_uint16_t;
+#else
 typedef uint64_t unaligned_uint64_t __rte_aligned(1);
 typedef uint32_t unaligned_uint32_t __rte_aligned(1);
 typedef uint16_t unaligned_uint16_t __rte_aligned(1);
-#else
-typedef uint64_t unaligned_uint64_t;
-typedef uint32_t unaligned_uint32_t;
-typedef uint16_t unaligned_uint16_t;
 #endif
 
 /**
-- 
2.53.0