[dpdk-dev] [PATCH v2] hash: fix breaking strict-aliasing rules

[Yerden Zhumabekov]

Fix rte_hash_crc() function by making use of uintptr_t variable
to hold a pointer to data being hashed. In this way, casting uint64_t
pointer to uint32_t avoided.

Signed-off-by: Yerden Zhumabekov <e_zhumabekov at sts.kz>
---
 lib/librte_hash/rte_hash_crc.h |   21 +++++++++++----------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/lib/librte_hash/rte_hash_crc.h b/lib/librte_hash/rte_hash_crc.h
index 1cd626c..abdbd9a 100644
--- a/lib/librte_hash/rte_hash_crc.h
+++ b/lib/librte_hash/rte_hash_crc.h
@@ -513,35 +513,36 @@ rte_hash_crc(const void *data, uint32_t data_len, 
uint32_t init_val)
 {
        unsigned i;
        uint64_t temp = 0;
-       const uint64_t *p64 = (const uint64_t *)data;
+       uintptr_t pd = (uintptr_t) data;

        for (i = 0; i < data_len / 8; i++) {
-               init_val = rte_hash_crc_8byte(*p64++, init_val);
+               init_val = rte_hash_crc_8byte(*(const uint64_t *)pd, init_val);
+               pd += 8;
        }

        switch (7 - (data_len & 0x07)) {
        case 0:
-               temp |= (uint64_t) *((const uint8_t *)p64 + 6) << 48;
+               temp |= (uint64_t) *((const uint8_t *)pd + 6) << 48;
                /* Fallthrough */
        case 1:
-               temp |= (uint64_t) *((const uint8_t *)p64 + 5) << 40;
+               temp |= (uint64_t) *((const uint8_t *)pd + 5) << 40;
                /* Fallthrough */
        case 2:
-               temp |= (uint64_t) *((const uint8_t *)p64 + 4) << 32;
-               temp |= *((const uint32_t *)p64);
+               temp |= (uint64_t) *((const uint8_t *)pd + 4) << 32;
+               temp |= *(const uint32_t *)pd;
                init_val = rte_hash_crc_8byte(temp, init_val);
                break;
        case 3:
-               init_val = rte_hash_crc_4byte(*(const uint32_t *)p64, init_val);
+               init_val = rte_hash_crc_4byte(*(const uint32_t *)pd, init_val);
                break;
        case 4:
-               temp |= *((const uint8_t *)p64 + 2) << 16;
+               temp |= *((const uint8_t *)pd + 2) << 16;
                /* Fallthrough */
        case 5:
-               temp |= *((const uint8_t *)p64 + 1) << 8;
+               temp |= *((const uint8_t *)pd + 1) << 8;
                /* Fallthrough */
        case 6:
-               temp |= *((const uint8_t *)p64);
+               temp |= *(const uint8_t *)pd;
                init_val = rte_hash_crc_4byte(temp, init_val);
                /* Fallthrough */
        default:
-- 
1.7.9.5