Crash/Illegal instruction with Clang on OS X

[rainman110]

In release mode, Clang creates illegal code in AdvApp2Var_ApproxF2var::mma2fnc_

This is a meta issue containing the information from

• Splinecage example crashes on OS X pythonocc-core#273
• http://tracker.dev.opencascade.org/view.php?id=26778

To reproduce:

   std::ifstream file("fillet_crash.brep");
   TopoDS_Shape shape;
    BRep_Builder b;
    BRepTools::Read(shape, file, b);
    for (TopExp_Explorer exp(shape, TopAbs_EDGE); exp.More(); exp.Next())
    {
        try
        {
            BRepFilletAPI_MakeFillet filletMaker(shape);
            filletMaker.Add(0.165405, TopoDS::Edge(exp.Current()));
            filletMaker.Build();
        }
        catch (...)
        {
        }
    }

The file fillet_crash.brep was downloaded from the occt mantis: fillet_crash.zip

Possible fixes:

• Compile src/AdvApp2Var/AdvApp2Var_ApproxF2var.cxx only with optimization level -O1
• or add __attribute__ ((noinline)) to the static functions of AdvApp2Var_ApproxF2var as suggested by Roman Lygin
• use the newest Clang (not tested yet) or a Clang older than 3.4

[ghost]

Repeat of #520, but we'll leave it open for the time being anyway. #520 was put over to OCCT due to the size of the issue.

[ghost]

This is fixed in OCCT master, closing.