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[Flang] Remove FLANG_INCLUDE_RUNTIME #124126

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Merged
merged 9 commits into from
Mar 26, 2025
Merged

[Flang] Remove FLANG_INCLUDE_RUNTIME #124126

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b14ff22
Remove FLANG_INCLUDE_RUNTIME
Meinersbur Feb 21, 2025
2bf7d33
Implicitly enable Flang-RT
Meinersbur Feb 21, 2025
85e290b
Merge branch 'main' into users/meinersbur/flang_runtime_remove-FLANG_…
Meinersbur Mar 13, 2025
cfbb2bb
Remove dead CMakeLists.txt
Meinersbur Mar 17, 2025
51dcd63
Move 'no runtime' warning to flang
Meinersbur Mar 17, 2025
15b9a82
Fix syntax error
Meinersbur Mar 17, 2025
a608a6f
Merge branch 'main' into users/meinersbur/flang_runtime_remove-FLANG_…
Meinersbur Mar 21, 2025
a207b4a
Merge branch 'main' into users/meinersbur/flang_runtime_remove-FLANG_…
Meinersbur Mar 26, 2025
efd146b
Group implicitly enabled projects/runtimes together
Meinersbur Mar 26, 2025
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Implicitly enable Flang-RT
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@Meinersbur
Meinersbur committed Feb 21, 2025
commit 2bf7d33978d965a68ed8697108e566a13fbb6340
7 changes: 6 additions & 1 deletion flang-rt/README.md
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Expand Up @@ -91,7 +91,12 @@ can be any compiler supporting the same ABI.
In addition to the compiler, the build be able to find LLVM development tools
such as `lit` and `FileCheck` that are not found in an LLVM's install
directory. Use `CMAKE_BINARY_DIR` to point to directory where LLVM has
been built. A simple build configuration might look like the following:
been built. When building Flang as part of a bootstrapping build
(`LLVM_ENABLE_PROJECTS=flang`), Flang-RT has already been automatically added
unless configured with `-DFLANG_ENABLE_FLANG_RT=OFF`. Add that option to avoid
having two conflicting versions of the same library.

A simple build configuration might look like the following:

```bash
cmake -S <path-to-llvm-project-source>/runtimes \
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13 changes: 13 additions & 0 deletions llvm/CMakeLists.txt
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Expand Up @@ -187,6 +187,19 @@ foreach(proj IN LISTS LLVM_ENABLE_RUNTIMES)
endif()
endforeach()

option(FLANG_ENABLE_FLANG_RT "Implicitly add LLVM_ENABLE_RUNTIMES=flang-rt when compiling Flang" ON)
if ("flang" IN_LIST LLVM_ENABLE_PROJECTS)
if (NOT "flang-rt" IN_LIST LLVM_ENABLE_RUNTIMES)
message(STATUS "Enabling Flang-RT as a dependency of Flang"
"Flang-RT is required for a fully working Flang toolchain."
"If you intend to compile Flang-RT separately following the instructions at"
"https://github.com/llvm/llvm-project/blob/main/flang-rt/README.md#standalone-runtimes-build"
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Directly linking to a github readme is a little weird. Do we not have a documentation page for this?

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There is no flang-rt.llvm.org . I do find several links to github.com in llvm/docs, such as

llvm-project/llvm/docs/TableGen/index.rst

Line 291 in 9387281

`README <https://github.com/llvm/llvm-project/blob/main/llvm/utils/TableGen/README.md>`_.

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@jhuber6 jhuber6 Mar 14, 2025 •
edited
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There's https://flang.llvm.org/docs/ right? it's not a blocking issue, I just feel like build configs are better shared through CMake config files or actual documentation.

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@Meinersbur Meinersbur Mar 17, 2025 •
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Is it ok to update the docs in a follow-up? Consolidating this README.md and https://flang.llvm.org/docs/GettingStarted.html#building-flang itself would be a larger patch. Also think that advanced topics like FLANG_RT_EXPERIMENTAL_OFFLOAD_SUPPORT does not belong into a GettingStarted.

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@Meinersbur Meinersbur Mar 17, 2025 •
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I moved the help message(...) to flang/ so a message is also emitted in a flang-standalone build (which is does not process LLVM_ENABLE_RUNTIMES at all). I also shortened it without the README link, may update it after consolidation.

"you should use -DFLANG_ENABLE_FLANG_RT=OFF to not build Flang-RT as part of this build."
)
list(APPEND LLVM_ENABLE_RUNTIMES "flang-rt")
endif()
endif ()

# Set a shorthand option to enable the GPU build of the 'libc' project.
option(LIBC_GPU_BUILD "Enable the 'libc' project targeting the GPU" OFF)
if(LIBC_GPU_BUILD)
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