| Issue |
154411
|
| Summary |
[doc] install target fails if ocaml_doc not built (missing ocamldoc/html directory)
|
| Labels |
new issue
|
| Assignees |
|
| Reporter |
Acture
|
### Description
When building with -DLLVM_BUILD_DOCS=ON -DLLVM_ENABLE_OCAMLDOC=ON -DLLVM_INSTALL_DOCS=ON, running
`cmake --build . --target install`
fails with:
```
CMake Error at docs/cmake_install.cmake:41 (file):
file INSTALL cannot find
"$HOME/llvm-project/build/docs/ocamldoc/html/.": No such file
or directory.
Call Stack (most recent call first):
cmake_install.cmake:162 (include)
```
### Steps to reproduce
Such error does not provoke with no OCAML.
```
mkdir build
cd build
cmake -G "Unix Makefiles" -DLLVM_TARGETS_TO_BUILD=AArch64 -DLLVM_DEFAULT_TARGET_TRIPLE=arm64-apple-darwin24.5.0 -DCMAKE_BUILD_TYPE="Release" -DLLVM_USE_LINKER=lld -DCMAKE_INSTALL_PREFIX="$HOME/repos/jeandle-llvm-install" -DLLVM_BUILD_DOCS=ON \
-DLLVM_ENABLE_OCAMLDOC=ON \
-DLLVM_INSTALL_DOCS=ON -DLLVM_BUILD_LLVM_DYLIB=On -DLLVM_DYLIB_COMPONENTS=all ../llvm
cmake --build . --target install
```
### Actual Behavior
install unconditionally tries to copy ${CMAKE_CURRENT_BINARY_DIR}/ocamldoc/html/. but that directory may not exist yet (the OCaml doc target has not been built), causing the install step to fail.
### Expected Behavior
Either:
- install should build the OCaml docs before installing them, or
- the OCaml docs should only be installed if they were generated (i.e., guarded by feature checks / target existence).
### Root Cause (CMake logic)
In llvm/docs/CMakeLists.txt the OCaml docs are generated by a custom target, but the install rule copies the output directory unconditionally:
```
install(DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/ocamldoc/html/.
COMPONENT ocamldoc-html
DESTINATION "${LLVM_INSTALL_OCAMLDOC_HTML_DIR}")
```
Unlike the Doxygen path (where doxygen-xxx targets are wired into a top-level doxygen target that participates in ALL), the OCaml docs target (ocaml_doc) is not on the build path that runs before install. As a result, cmake --build . --target install may execute before ${CMAKE_CURRENT_BINARY_DIR}/ocamldoc/html/ exists, and the copy fails.
### Workarounds
- Explicitly build the doc target before install:
```
cmake --build . --target ocaml_doc
cmake --build . --target install
```
- Or temporarily create the directory to unblock installation (not recommended):
```
mkdir -p build/docs/ocamldoc/html
cmake --build . --target install
```
### Environment
- OS: macOS (arm64-apple-darwin24.5.0)
- Toolchain: Apple Clang / lld
- OCaml tooling: ocamlc/ocamldoc/ocamlfind available and detected
- LLVM version/branch: (please fill in, e.g., 20.1.6 / commit SHA)
- Generator: Unix Makefiles
Same as shown in #125437 and #108742
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