[Vm-dev] Re: Xcode no longer includes gcc

[Stefan Marr]

Hi:

Most of the things you'll find are undefined behavior in C.

I posted at least one issue to the list (I think it had to do with overflow in one of the arithmetic primitives, multiplication or so).

My strategy to fix these things for the RoarVM was to use a bytecode trace, output to a file. And you have to make sure that you got as few as possible non-determinism. For that I disabled preemptive scheduling completely.

Afterwards I had two VMs, one compiled with GCC, and one with Clang. And then fixed the issues as they popped up.

Takes a bit, but it is possible.
The trace usually points at the bytecodes that behave incorrectly.

Hope that helps.
Stefan

On 11 Jan 2012, at 02:22, John McIntosh wrote:

> At the Apple Developer conference in 2009 the nice Apple LLVM folks told me, can we have a "small" code sample that shows the problem... 
> Fails on the old interpreter from that era, you should start with that, you don't actually need to step "too much" in order to get it to die btw.
> 
> On Tue, Jan 10, 2012 at 8:16 PM, Sean P. DeNigris <sean at clipperadams.com> wrote:
> 
> 
> EstebanLM wrote
> >
> > gcc is still there...
> >
> 
> Not with a fresh install of Xcode 4.2! See
> http://ask.metafilter.com/200231/How-to-install-gcc-42-on-a-macbook-with-Xcode-42
> 
> I was able to get it and fix Xcode:
> 1) install via Mac Ports: "sudo port install apple-gcc42"
> 2) Follow http://stackoverflow.com/a/8593831/424245 to get it to appear in
> Xcode, the last two steps will probably look like:
>  a) sudo ln -s /opt/local/bin/gcc-apple-4.2 /Developer/usr/bin/gcc-4.2
>  b) sudo ln -s /opt/local/bin/g++-apple-4.2 /Developer/usr/bin/g++-4.2
> 
> --
> View this message in context: http://forum.world.st/Xcode-no-longer-includes-gcc-tp4283855p4284100.html
> Sent from the Squeak VM mailing list archive at Nabble.com.
> 
> 
> 
> -- 
> ===========================================================================
> John M. McIntosh <johnmci at smalltalkconsulting.com>
> Corporate Smalltalk Consulting Ltd.  http://www.smalltalkconsulting.com
> ===========================================================================
> 
> 
> 

-- 
Stefan Marr
Software Languages Lab
Vrije Universiteit Brussel
Pleinlaan 2 / B-1050 Brussels / Belgium
http://soft.vub.ac.be/~smarr
Phone: +32 2 629 2974
Fax:   +32 2 629 3525