asavonic added a comment. In https://reviews.llvm.org/D51544#1224730, @Anastasia wrote:
> It seems generally good to partition this big header but I am trying to > understand what problem is it trying to solve now? Main motivation is to reduce memory footprint by factoring out everything that is 'common' between PCHs compiled for different targets (CL1.2/2.0 and spir/spir64). > So if we want to add these 2 devices, we now need 4*2 different PCHs, > since every combination of -cl-std and -triple must be compiled twice > with different OpenCL extensions defines. > > Size of each PCH is 2.5M, so we need ~20M of memory to store our > PCHs. If we want to add more devices or support another OpenCL C > version, the size will double. This also allows to do 'partial' pre-compilation, where 'common' part is pre-compiled into a single target independent PCH, and plain header is used for all target-specific things. In this case, you no longer need to maintain different target-specific PCHs and this greatly simplifies the whole process. > opencl-c-platform.h (5K LOC) must still be pre-compiled for each > supported combination, but since it is a lot smaller (~0.5M vs > original 2.5M), it is not that bad. Or we can sacrifice some > performance and leave this header without pre-compilation: large > portion of opencl-c-platform.h contains vendor extensions, so it will > be removed by preprocessor anyway. Repository: rC Clang https://reviews.llvm.org/D51544 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
