Fix segfault when managed memory is not used. (#147)

Source/Projection.cpp

@@ -1961,8 +1961,22 @@ Projection::computeRhoG(FArrayBox* rhoFab,
  {
  const auto lo = amrex::lbound(phiFab[iface].box());
  const auto hi = amrex::ubound(phiFab[iface].box());
+#ifdef AMREX_USE_GPU
+ FArrayBox h_phiFab(phiFab[iface].box(), phiFab[iface].nComp(),
+ The_Pinned_Arena());
+ FArrayBox h_rhoFab(rhoFab[iface].box(), rhoFab[iface].nComp(),
+ The_Pinned_Arena());
+ Gpu::dtoh_memcpy_async(h_phiFab.dataPtr(), phiFab[iface].dataPtr(),
+ h_phiFab.nBytes());
+ Gpu::dtoh_memcpy_async(h_rhoFab.dataPtr(), rhoFab[iface].dataPtr(),
+ h_rhoFab.nBytes());
+ Gpu::streamSynchronize();
+ const auto& phi = h_phiFab.array();
+ const auto& rho = h_rhoFab.array();
+#else
  const auto& phi = phiFab[iface].array();
  const auto& rho = rhoFab[iface].array();
+#endif
  const Real dh = geom.CellSize(AMREX_SPACEDIM-1);
 
  auto add_rhog = [gravity, dh] ( Real rho1, Real rho2,
@@ -2352,6 +2366,14 @@ Projection::computeRhoG(FArrayBox* rhoFab,
  } // endif over hi/low sides
  } // endif over directions
 #endif
+
+#ifdef AMREX_USE_GPU
+ Gpu::htod_memcpy_async(phiFab[iface].dataPtr(), h_phiFab.dataPtr(),
+ phiFab[iface].nBytes());
+ Gpu::htod_memcpy_async(rhoFab[iface].dataPtr(), h_rhoFab.dataPtr(),
+ rhoFab[iface].nBytes());
+ Gpu::streamSynchronize();
+#endif
  } // endif integrate rho*g*dh
  } // end loop over outflow faces
 }