[a5b4d9d9a] Uninit vals in SightCheck::PTR_SightTraverse

[Blzut3]

Trying to clean up the warning output on GCC since it has been left to get out of hand. This warning appears to be a potentially real issue, but I don't have the time to construct test cases to properly solve it.

Code: Select all

/home/blzut3/Code/GZDoom/src/p_sight.cpp: In member function ‘bool SightCheck::PTR_SightTraverse(intercept_t*)’:
/home/blzut3/Code/GZDoom/src/p_sight.cpp:241:24: warning: ‘open.SightOpening::top’ may be used uninitialized in this function [-Wmaybe-uninitialized]
   slope = (open.bottom - sightstart.Z) / in->frac;
           ~~~~~~~~~~~~~^~~~~~~~~~~~~~~

In English the issue is that P_SightOpening may not initialize open.bottom/open.top. GCC's static analysis is able to determine that as a result LineBlocksSight must return true in that case and thus open.bottom has the same uninitialized value as open.top.

As open.portalflags can be non zero, these bogus values are used to calculate slopes which may in turn be passed through the portal code before the function finally returns.

[Graf Zahl]

I hope I got it fixed but I do not have a good test case at my disposal.