bafde6fbb8
Reapplication of #137828 and #169638 Move building the .mod files from openmp/flang to openmp/flang-rt using a shared mechanism. Motivations to do so are: 1. Most modules are target-dependent and need to be re-compiled for each target separately, which is something the LLVM_ENABLE_RUNTIMES system already does. Prime example is `iso_c_binding.mod` which encodes the target's ABI. Constants such as `c_long_double` also have different values). Most other modules have `#ifdef`-enclosed code as well. For instance this caused offload targets nvptx64-nvidia-cuda/amdgpu-amd-amdhsa to use the modules files compiled for the host which may contrain uses of the types REAL(10) or REAL(16) not available for nvptx/amdgpu. 2. CMake has support for Fortran that we should use. Among other things, it automatically determines module dependencies so there is no need to hardcode them in the CMakeLists.txt. Currently the dependencies between builtin modules and `omp_lib.mod` seem to be incorrect: https://github.com/llvm/llvm-project/pull/174474#issuecomment-3880189581 3. It allows using Fortran itself to implement Flang-RT. Currently, only `iso_fortran_env_impl.f90` emits object files that are needed by Fortran applications (#89403). The workaround of #95388 could be reverted (PR #169525). If using Flang for cross-compilation or target-offloading, flang-rt must now be compiled for each target not only for the library, but also to get the target-specific module files. For instance in a bootstrapping runtime build, this can be done by adding: `-DLLVM_RUNTIME_TARGETS=default;nvptx64-nvidia-cuda;amdgpu-amd-amdhsa`. Some new dependencies come into play: * openmp depends on flang-rt for building `lib_omp.mod` and `lib_omp_kinds.mod`. Currently, if flang-rt is not found then the modules are not built. * check-flang depends on flang-rt: If not found, the majority of tests are disabled. If not building in a bootstrpping build, the location of the module files can be pointed to using `-DFLANG_INTRINSIC_MODULES_DIR=<path>`, e.g. in a flang-standalone build. Alternatively, the test needing any of the intrinsic modules could be marked with `REQUIRES: flangrt-modules`. * check-flang depends on openmp: Not a change; tests requiring `lib_omp.mod` and `lib_omp_kinds.mod` those are already marked with `openmp_runtime`. As intrinsic are now specific to the target, their location is moved from `include/flang` to `<resource-dir>/finclude/flang/<triple>`. The mechnism to compute the location have been moved from flang-rt (previously used to compute the location of `libflang_rt.*.a`) to common locations in `cmake/GetToolchainDirs.cmake` and `runtimes/CMakeLists.txt` so they can be used by both, openmp and flang-rt. Potentially the mechnism could also be shared by other libraries such as compiler-rt. `finclude` was chosen because `gfortran` uses it as well and avoids misuse such as `#include <flang/iso_c_binding.mod>`. The search location is now determined by `ToolChain` in the driver, instead of by the frontend. Another subdirectory `flang` avoids accidental inclusion of gfortran-modules which due to compression would result in user-unfriendly errors. Now the driver adds `-fintrinsic-module-path` for that location to the frontend call (Just like gfortran does). Since the driver determines the location, tests invoking `flang -fc1` and `bbc` must also be passed the location by llvm-lit. This works like llvm-lit does for finding the include dirs for Clang using `-print-file-name=...`.
30 lines
938 B
CMake
30 lines
938 B
CMake
include(CMakePushCheckState)
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include(CheckFortranSourceCompiles)
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# Check whether the Fortran compiler supports real(16)/quadmath types
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#
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# Implementation notes:
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#
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# * FORTRAN_SUPPORTS_REAL16 can be set externally in a bootstrapping-runtimes
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# build to ensure consistency of real(16) support between compiler and
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# runtime.
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#
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# * cmake_push_check_state/cmake_pop_check_state is insufficient to isolate
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# a compiler introspection environment, see
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# https://gitlab.kitware.com/cmake/cmake/-/issues/27419
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# Additionally wrap it in a function namespace.
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#
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function (check_fortran_quadmath_support)
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cmake_push_check_state(RESET)
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set(CMAKE_REQUIRED_FLAGS "-ffree-form")
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set(CMAKE_TRY_COMPILE_TARGET_TYPE "STATIC_LIBRARY") # Skip link step
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check_fortran_source_compiles([[
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subroutine test_quadmath
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real(16) :: var1
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end
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]]
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FORTRAN_SUPPORTS_REAL16
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)
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cmake_pop_check_state()
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endfunction ()
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