[SystemZ][z/OS] Fix cityhash lit for EBCDIC

[zibi]

Summary

This will fix __murmur2_or_cityhash.pass.cpp in EBCDIC mode. The reason it fails is because of string literals are being used as input to CityHash algorithm so we need to adjust the EBCDIC expected results.

[zibi]

The above pre-merge checks failures are timeout and not related to this patch. Submitting again to get clean build status.

[philnik]

In D141623#4052417, @zibi wrote:

The above pre-merge checks failures are timeout and not related to this patch. Submitting again to get clean build status.

You don't have to get a green CI in the sense that all tests fail. If the failures are unrelated you can also consider it green. (You should be sure though)

libcxx/test/libcxx/utilities/utility/__murmur2_or_cityhash.pass.cpp

32–35

Couldn't we just change these to char arrays with numbers instead of a string that might be different between platforms? That should make the Test platform independent.

[zibi]

Addressing comments ...

[zibi]

libcxx/test/libcxx/utilities/utility/__murmur2_or_cityhash.pass.cpp

32–35

Thank you for looking at it and your comments.

Is the new patch is what you meant? I think we want the numbers to be more than just what char can hold.

[zibi]

• Fix cityhash lit for EBCDIC
• Switch to array of strings with hard coded values

[EricWF]

libcxx/test/libcxx/utilities/utility/__murmur2_or_cityhash.pass.cpp

23

Does this compile?

[zibi]

• fix typo

[zibi]

libcxx/test/libcxx/utilities/utility/__murmur2_or_cityhash.pass.cpp

23

I guess not, it should be now, thx.

[zibi]

FYI, the failure ia the timeout on Apple, unrelated to this patch, so consider CI checks as green.

[philnik]

libcxx/test/libcxx/utilities/utility/__murmur2_or_cityhash.pass.cpp

27

I thought more of just making this {43, 69, 74, 48, 61, 73, 68}. Or is there a reason not to do that?

[zibi]

Change to use an array of integers instead of strings.

[zibi]

libcxx/test/libcxx/utilities/utility/__murmur2_or_cityhash.pass.cpp

27

Yes, we can do that. I used hex values, otherwise I would need to convert them to decimal values.

[tahonermann]

libcxx/test/libcxx/utilities/utility/__murmur2_or_cityhash.pass.cpp

27

I think the numeric hex escapes in a string literal were a better solution. When char is a signed 8-bit type, use of the initializer_list will reject narrowing conversions that occur when a code point value above 0x7F is needed.

[zibi]

libcxx/test/libcxx/utilities/utility/__murmur2_or_cityhash.pass.cpp

27

Yes, you are right. At the moment we don't have anything > 0x7F so we are fine however, future expansion might introduce this issue.

I propose to reverse last commit.

[zibi]

• Revert "[SystemZ][z/OS] Fix cityhash lit for EBCDIC"

[zibi]

FYI, the failures reported are unrelated.
They are either timeouts or taking unexpectedly too long (assertion in std/thread/futures/futures.async/async.pass.cpp at line 102).

libcxx/test/libcxx/utilities/utility/__murmur2_or_cityhash.pass.cpp

 #include <utility>
 
 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
 #  define CHOOSE_BY_ENDIANESS(little, big) (little)
 #else
 #  define CHOOSE_BY_ENDIANESS(little, big) (big)
 #endif
 
 std::string CityHash[] = {
-    {/* "abcdefgh" */ "\x61\x62\x63\x64\x65\x66\x67\x68"},
-    {/* "abcDefgh" */ "\x61\x62\x63\x44\x65\x66\x67\x68"},
-    {/* "CityHash" */ "\x43\x69\x74\x79\x48\x61\x73\x68"},
-    {/* "CitYHash" */ "\x43\x69\x74\x59\x48\x61\x73\x68"},
+    {/* "abcdefgh" */ 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68},
+    {/* "abcDefgh" */ 0x61, 0x62, 0x63, 0x44, 0x65, 0x66, 0x67, 0x68},
+    {/* "CityHash" */ 0x43, 0x69, 0x74, 0x79, 0x48, 0x61, 0x73, 0x68},
+    {/* "CitYHash" */ 0x43, 0x69, 0x74, 0x59, 0x48, 0x61, 0x73, 0x68},
 };
 
 int main(int, char**) {
   const std::pair<std::string, uint64_t> TestCases[] = {
       {CityHash[0], CHOOSE_BY_ENDIANESS(0x4382a8d0fe8edb17ULL, 0xca84e809bef16fbcULL)},
       {CityHash[1], CHOOSE_BY_ENDIANESS(0xecefb080a6854061ULL, 0xd7feb824250272dcULL)},
       {CityHash[2], CHOOSE_BY_ENDIANESS(0x169ea3aebf908d6dULL, 0xea8cef3ca6f6e368ULL)},
       {CityHash[3], CHOOSE_BY_ENDIANESS(0xe18298a2760f09faULL, 0xf33a7700bb7a94a8ULL)},
   };
 
   std::__murmur2_or_cityhash<uint64_t> h64;
   for (const auto& test_case : TestCases) {
     assert(h64(test_case.first.data(), test_case.first.size()) == test_case.second);
   }
   return 0;
 }