I have a code base that compiles fine with Visual Studio. I keep on getting error 139 when I compile them with gcc for Cygwin.

It always happens for specific files. I.e., I can spend a lot of time and track down that if I disable say some assignment operator and that file would compile.

Now that all individual .cpp files compile to .o files, the linker step gives me the same 139 error.

Officially, error 139 is supposed to be a gcc memory corruption/bad installation error of some sort:
http://stason.org/TULARC/os/linux-faq/141-Make-Says-Error-139.html

But I reinstalled Cygwin and gcc to different folder/drive and still get same result.

I don't know how to debug this.