pscoro added inline comments.
================ Comment at: flang/runtime/CMakeLists.txt:251 - INSTALL_WITH_TOOLCHAIN -) +if (DEFINED LLVM_ENABLE_RUNTIMES AND "flang-rt" IN_LIST LLVM_ENABLE_RUNTIMES) + add_flang_library(FortranRuntime STATIC ---------------- efriedma wrote: > pscoro wrote: > > efriedma wrote: > > > This "if" doesn't make sense to me. If we're not building flang-rt, we > > > shouldn't be here, so I don't see why you need an "if" in the first place. > > `add_subdirectory(runtime)` is a line that still exists in > > `flang/CMakeLists.txt`. This exists because `Fortran_main` is still being > > built at the same time as the compiler, and to do so, the runtime > > subdirectory still needs to be added to flang (`flang/CMakeLists.txt` -> > > `add_subdirectory(runtime)` -> `flang/runtime/CMakeLists.txt` -> > > `add_subdirectory(FortranMain)`. The solution I had was to just add a check > > around the `FortranRuntime` library production so that it only happens for > > flang-rt. > > > > If you have a better solution let me know. Overall, I'm not sure if > > Fortran_main is currently being handled in the best way (ie, its still > > being built at the same time as the compiler, which doesn't seem ideal), > > but am not sure what course of action to take with it since it doesn't > > really belong in flang-rt either (see documentation for details) > Fortran_main should be "part of" flang-rt in the sense that building flang-rt > builds it. Most of the same reasons we want to build flang-rt.a as a runtime > apply. > > Since the output needs to be separate, building flang-rt should produce two > libraries: flang-rt.a and FortranMain.a. I agree with this idea and have been trying to make it work but in the process I discovered that my "fix" above (`if (DEFINED LLVM_ENABLE_RUNTIMES AND "flang-rt" IN_LIST LLVM_ENABLE_RUNTIMES)`) is worse than I thought. By building the llvm target with flang-rt as an enabled runtime, we are essentially saying: build the flang compiler, and then invoke cmake again to build the runtimes project (externally), which builds flang-rt. The problem is that check-all depends on check-flang which depends on the runtime. The if guard above was not actually doing what I thought it was, and the reason why configuring didnt fail with "flang-rt does not exist" is because the if guard was still evaluating to true. Basically, the guard ensured that FortranRuntime was only being built if flang-rt is built, but the add_library call was still being reached *during the configuration of the flang compiler*. I am having trouble dealing with this dependency since runtimes get built externally (and after the compiler is built, which is when the check-all custom target gets built). I will have to investigate more closely how other runtimes handle this. My initial thought was perhaps the runtime testing should be decoupled from check-flang/check-all however I don't know if that's a good idea, and I also think that only helps with flang-rt, but if Fortran_main is required to build any executable I imagine that it should be needed for check-flang? This is just an update of whats holding me back right now. If you have any tips please let me know. Thanks for bringing this to my attention. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D154869/new/ https://reviews.llvm.org/D154869 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
