On 2024-10-16 13:30, David Marchand wrote:
On Thu, Oct 10, 2024 at 10:30 AM David Marchand
<david.march...@redhat.com> wrote:
diff --git a/lib/eal/include/rte_bitset.h b/lib/eal/include/rte_bitset.h
new file mode 100644
index 0000000000..b2d71aa7c6
--- /dev/null
+++ b/lib/eal/include/rte_bitset.h

[snip]

+__rte_experimental
+static inline ssize_t
+__rte_bitset_find_nowrap(const uint64_t *bitset, size_t __rte_unused size, 
size_t start_bit,
+               size_t len, bool find_clear)
+{
+       size_t word_idx;
+       size_t offset;
+       size_t end_bit = start_bit + len;
+
+       RTE_ASSERT(end_bit <= size);
+
+       if (unlikely(len == 0))
+               return -1;
+
+       word_idx = __RTE_BITSET_WORD_IDX(start_bit);
+       offset = __RTE_BITSET_BIT_OFFSET(start_bit);
+
+       while (word_idx <= __RTE_BITSET_WORD_IDX(end_bit - 1)) {
+               uint64_t word;
+               int word_ffs;
+
+               word = bitset[word_idx];
+               if (find_clear)
+                       word = ~word;
+
+               word >>= offset;
+
+               word_ffs = __builtin_ffsll(word);
+
+               if (word_ffs != 0) {
+                       ssize_t ffs = start_bit + word_ffs - 1;
+
+                       /*
+                        * Check if set bit were among the last,
+                        * unused bits, in the last word.
+                        */
+                       if (unlikely(ffs >= (ssize_t)end_bit))
+                               return -1;
+
+                       return ffs;
+               }
+
+               start_bit += (RTE_BITSET_WORD_BITS - offset);
+               word_idx++;
+               offset = 0;
+       }
+
+       return -1;
+
+}

Now that the series is merged, we finally got one report from UNH and
this patch breaks MSVC build.

FAILED: lib/librte_eal.a.p/eal_common_rte_bitset.c.obj
"cl" "-Ilib\librte_eal.a.p" "-Ilib" "-I..\lib" "-I." "-I.." "-Iconfig"
"-I..\config" "-Ilib\eal\include" "-I..\lib\eal\include"
"-Ilib\eal\windows\include" "-I..\lib\eal\windows\include"
"-Ilib\eal\x86\include" "-I..\lib\eal\x86\include" "-Ilib\eal\common"
"-I..\lib\eal\common" "-Ilib\eal" "-I..\lib\eal" "-Ilib\log"
"-I..\lib\log" "-Ilib\kvargs" "-I..\lib\kvargs" "-IC:\Program
Files\Mellanox\MLNX_WinOF2_DevX_SDK\inc" "/MD" "/nologo"
"/showIncludes" "/W3" "/WX" "/std:c11" "/O2" "/Gw" "/wd4244" "/wd4267"
"/wd4146" "/experimental:c11atomics" "/d1experimental:typeof"
"/experimental:statementExpressions" "/FI" "rte_config.h"
"-D_GNU_SOURCE" "-D_WIN32_WINNT=0x0A00" "-DALLOW_EXPERIMENTAL_API"
"-DALLOW_INTERNAL_API" "-DABI_VERSION=\"25.0\""
"-DRTE_LOG_DEFAULT_LOGTYPE=lib.eal"
"/Fdlib\librte_eal.a.p\eal_common_rte_bitset.c.pdb"
/Folib/librte_eal.a.p/eal_common_rte_bitset.c.obj "/c"
../lib/eal/common/rte_bitset.c
..\lib\eal\include\rte_bitset.h(612): error C2220: the following
warning is treated as an error
..\lib\eal\include\rte_bitset.h(612): warning C4013: '__builtin_ffsll'
undefined; assuming extern returning int


I see two options:
- rewrite this code and use existing rte_ctz64 or rte_bsf64_safe,
- introduce an additional rte_ffs64() in rte_bitops.h and implement it
for MSVC and others,

And I would prefer we extend checkpatch, so that such issue is caught earlier.
See:
devtools/checkpatches.sh:               -v
EXPRESSIONS='\\<__builtin_(clz|clzll|ctz|ctzll|popcount|popcountll)\\>'
\

Please send a fix.



Will do.

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