Le Mon, 07 Apr 2014 13:48:54 +0200, Jean-Pierre Flori a écrit : > Dear all, > > While preparing a new release of MPIR (mpir.org) we encountered issues > on Cygwin64. > A detailed discussion of the issue is already available on Cygwin > mailing list: > http://cygwin.com/ml/cygwin/2014-04/msg00005.html and follow-ups. > > Quickly it seems the problem seem to be that calling assembly defined > functions (assembled with yasm) without the __declspec(dllimport) > magic leads to a "callq" instruction with a chopped off address instead > of a correct magic trampoline code. > This seems to be the case with both gcc 4.7.3 and 4.8.2 but the culprit > might be elsewhere. > Our current solution is to use the _declspec(dllimport) magic, but as it > should not be necessary anymore, it would be nice to understand what is > going wrong here. > > Looking a little bit at the import lib produced by gcc, it seems that > problematic symbols have the __nm_ prefix, whereas non-problematic one > don't. > Any clue on how this is decided? > In particular, when tryng to compile a minimal lib with dummy function I > don't get __nm_ prefixes. > > Best, Ok, it seems we got the problem: assembly files in MPIR don't add the yasm export directive (.def for gas), whereas gcc/gas add it by default ; whence the discrepancies in symbol produced in the import library.
