Comments on: Valgrind + Mac OS X update (Feb 17, 2009)

By: Jens Alfke

Jens Alfke — Thu, 19 Mar 2009 21:02:06 +0000

For the record, Jason Oster’s comment above is wrong. OS X 10.5 definitely supports 64-bit apps, even at the GUI level. (Xcode itself runs 64-bit.) I can vouch for this, as I helped fix a number of 64-bit compatibility bugs in 10.5 back when I still worked at Apple =)

Unlike Windows, there is no separate 32 or 64 bit mode for the OS. If the CPU is 64-bit-capable, the kernel supports both 32 and 64 bit apps running at the same time. If the executable contains a 64-bit binary, it will use that preferentially to a 32-bit one.

By: Nicholas Nethercote

Nicholas Nethercote — Mon, 02 Mar 2009 05:02:24 +0000

Andy: best place to report problems is Bugzilla: http://www.valgrind.org/support/bug_reports.html. If you could report this there so it doesn’t get lost that would be great. Thanks.

By: Andy

Andy — Mon, 02 Mar 2009 04:30:54 +0000

Do you have a place where we can report issues or ask questions?

I’m getting this:

–51712– WARNING: unhandled syscall: 33554700
–51712– a.k.a.: 268
==51712== at 0xB6DDE2: sem_open (in /usr/lib/libSystem.B.dylib)
…

Looking at the syswrap and vki stuff, it is listed, just don’t know what else needs to be done to make it work…

BTW: Big thanks for your work on this! I’ve really missed valgrind since I moved away from developing on Linux.

By: Nicholas Nethercote

Nicholas Nethercote — Sat, 21 Feb 2009 23:21:57 +0000

Jesse: that’s good to know. It seems that __sigaction(), __disable_threadsignal() and wait4_nocancel() (syscall 400) are the only unhandled things, and that the current strategy of ignoring them works! Getting signals working under Valgrind on Mac still would seem like a good idea

And it seems a bit dodgy that NSPR asserts that sigaction() doesn’t return -1.

By: Jesse Ruderman

Jesse Ruderman — Sat, 21 Feb 2009 23:06:42 +0000

Firefox actually runs just fine if you comment out the assertion in NSPR.

Patch to comment out the assertion: http://pastebin.mozilla.org/627682

Output from running Firefox, loading Tinderbox, and quitting: http://pastebin.mozilla.org/627688

I imagine using an opt-with-symbols build rather than a debug build would make the experience even more pleasant and not require commenting out the assertion. But all I had handy was a debug build.

By: Nicholas Nethercote

Nicholas Nethercote — Tue, 17 Feb 2009 21:51:11 +0000

Thanks for the suggestions. I should have given some more info about the 64-bit issue.

Mac OS X 10.5 is clearly claiming to be a 32-bit OS — ‘uname -m’ gives “i386″, and normal compilation produces 32-bit executables. However, using ‘gcc -m64′ or ‘gcc -arch x86_64′ produces 64-bit executables, with 8-byte pointers, and the OS happily runs them. So it’s 64-bit capable.

In general, on 64-bit platforms, Valgrind builds itself twice, once as 64-bit and once as 32-bit; the 64-bit version handles 64-bit executables, and the 32-bit version handles 32-bit executables. The build machinery uses -m32 and -m64 as required to make this happen. This assumes that configure detects that the machine is 64-bit in the first place.

So if configure detected that the machine is 64-bit capable, both versions would build without problem. However, the $host_cpu variable which is set by AC_CANONICAL_HOST gets the value “i386″. I just tried hacking the configure script to force $host_cpu to “x86_64″ and both versions were successfully built, and they both work. And using –host=x86_64-darwin also works and is a cleaner way to do it.

So, problem solved! At least, with a workaround. Presumably in 10.6 the OS will claim to be 64-bit, as per Jason’s comment, and so configure will set $host_cpu to x86_64.

By: Jason Oster

Jason Oster — Tue, 17 Feb 2009 18:19:47 +0000

If it’s any help, Mac OS X 10.5 is still a 32-bit only OS. (Even in Cocoa.) 10.6 is currently scheduled to support 64-bit.

By: Josh Aas

Josh Aas — Tue, 17 Feb 2009 15:34:47 +0000

There is a mozconfig file for Mozilla’s build system that will get Mozilla building 64-bit on Mac OS X 10.5 on Mozilla bug 468509 (the build won’t finish but the compiler setup is fine afaict). Building 64-bit on Mac OS X 10.5 is considered cross compiling in our system though, I’m not sure how Xcode’s UI does it. I realize that file isn’t directly applicable to valgrind but you might be able to deduce the information you need from it.

By: Ian M

Ian M — Tue, 17 Feb 2009 09:41:52 +0000

Dumb suggestion – are you sure the OS is running as 64-bit?