[tor-dev] building from source in a 64-bit windows environment..

[Blibbet]

In addition to Tor codebase, you also need to get external dependent 
libraries working with Win64. LibEvent got some MinGW64 patches last 
year, I believe. The OpenSSL binary distributions come in both Win32 and 
Win64 versions. I'm not sure if base zlib has a working Win64 port, but 
there's also the zlib-Win64.GoogleCode that appears to be working on 
this problem.

Yes, it's a combo of API and OS subsystem simplification, not just 
subsystem. As for more information on perf, I seem to recall some MSFT 
VC++ white paper back when Win64 porting was a new thing, with some more 
details. And some commercial VS addon that helps migrate code from Win32 
to Win64 also to have some case studies. Sorry, can't find URLs to 
either. It will be really interesting to see some perf data with your 
Win64 version of Tor!

For packaging, alternately, keep the normal number of packages, but make 
each one 2* the size, and update the installer to install the right 
version, and force all uses to download an unneeded version of Tor binary.

Long term, for the Tor codebase on Windows, besides 32- and 64-bit 
versions for Intel/AMD, also look into 32-bit ARM release. For Win8, for 
Win32-based OEM netbooks/tablets, perhaps even the MSFT Surface tablets 
(one is x86, one is ARM). WinPhone7 was too restricted to run Tor (or 
any Win32 app) on it. WinPhone8 can apparently run native Win32 C ARM 
code, but is still based on WinCE/WinMobile, no security, weird 
WinCE/WinMobile OS/libC hacks required. There's hope that NT will 
finally kill off CE, and that Windows Phone 9 or 10 will be based on NT 
not CE/WinMobile, likely 32-bit ARM-based. An ARM port is needed for any 
of these non-x86 platforms.