(+cc: Marc Stevens) Ævar Arnfjörð Bjarmason wrote: > On Wed, May 09 2018, jens persson wrote: >> Hello, first patch. I'm having trouble compiling on AIX using IBMs >> compiler, leading to >> unusable binaries. The following patch solved the problem for 2.17.0. >> The patch below is cut&pasted via gmail to allow for firewalls, but >> exists in an unmolested form on github: >> https://github.com/MrShark/git/commit/44bfcaca6637e24548ec06f46fb6035a846b14af >> >> Best regards >> /jp Thanks for the patch. >> Building on AIX using XLC every checkout gives an error: >> fatal: pack is corrupted (SHA1 mismatch) >> fatal: index-pack failed >> >> Back tracking it was introduced in 2.13.2, most likely in [1] >> >> Add a #ifdef guard based on macros defined at [2] and [3]. >> >> Should perhaps __xlc__ should should be changed to or combined with _AIX >> based on the behavour of GCC on AIX or XL C on Linux. >> >> 1. https://github.com/git/git/commit/6b851e536b05e0c8c61f77b9e4c3e7cedea39ff8 >> 2. https://www.ibm.com/support/knowledgecenter/SSGH2K_13.1.3/com.ibm.xlc1313.aix.doc/compiler_ref/macros_platform.html >> 3. https://www.ibm.com/support/knowledgecenter/SSGH2K_13.1.3/com.ibm.xlc1313.aix.doc/compiler_ref/xlmacros.html >> >> Signed-off-by: jens persson <jens@xxxxxxxxxx> >> --- >> sha1dc/sha1.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/sha1dc/sha1.c b/sha1dc/sha1.c >> index 25eded139..68a8a0180 100644 >> --- a/sha1dc/sha1.c >> +++ b/sha1dc/sha1.c >> @@ -84,7 +84,7 @@ >> /* Not under GCC-alike or glibc or *BSD or newlib */ >> #elif (defined(__ARMEB__) || defined(__THUMBEB__) || defined(__AARCH64EB__) || \ >> defined(__MIPSEB__) || defined(__MIPSEB) || defined(_MIPSEB) || \ >> - defined(__sparc)) >> + defined(__sparc) || (defined(__powerpc) && defined(__xlc__))) I wonder if there's a simpler way to detect this. __powerpc seems orthogonal to the goal, since there are little-endian powerpc machines. It appears that XLC defines _BIG_ENDIAN on big-endian machines. I wonder if we should do #elif defined(_BYTE_ORDER) && defined(_BIG_ENDIAN) && defined(_LITTLE_ENDIAN) ... as today ... #elif !defined(_BYTE_ORDER) && defined(_BIG_ENDIAN) && !defined(_LITTLE_ENDIAN) # define SHA1DC_BIGENDIAN #elif !defined(_BYTE_ORDER) && !defined(_BIG_ENDIAN) && defined(_LITTLE_ENDIAN) /* little endian. */ #else ... It also seems to me that Git should enable the #error in the fallthrough case. The test suite would catch this kind of problem but it does not seem that everyone runs the test suite, so a compiler error is more robust. Is there a #define we can set to enable that? >> /* >> * Should define Big Endian for a whitelist of known processors. See >> * https://sourceforge.net/p/predef/wiki/Endianness/ and > > This patch looks sane to me, but we don't manage this software but > instead try to pull it as-is from upstream at > https://github.com/cr-marcstevens/sha1collisiondetection > > Which we could apply this, it would be much better if you could submit a > pull request with this to upstream, and then we can update our copy as I > did in e.g. 9936c1b52a ("sha1dc: update from upstream", 2017-07-01). Thanks, Jonathan
