[libcxx-commits] [libcxx] [libcxx] [modules] Fix relative paths with absolute LIBCXX_INSTALL_MODULES_DIR (PR #85756)

[via libcxx-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-libcxx

Author: Martin Storsjö (mstorsjo)

<details>
<summary>Changes</summary>

In other contexts, install directories such as
LIBCXX_INSTALL_LIBRARY_DIR and LIBCXX_INSTALL_MODULES_DIR can be specified either as a relative path, relative to CMAKE_INSTALL_PREFIX, or as an absolute path.

When calculating the relative path between the two, account for the fact that LIBCXX_INSTALL_MODULES_DIR and LIBCXX_INSTALL_LIBRARY_DIR can be absolute paths too.

---
Full diff: https://github.com/llvm/llvm-project/pull/85756.diff


1 Files Affected:

- (modified) libcxx/modules/CMakeLists.txt (+13-2) 


``````````diff
diff --git a/libcxx/modules/CMakeLists.txt b/libcxx/modules/CMakeLists.txt
index 0dea8cfca94ac3..08deb452f5579a 100644
--- a/libcxx/modules/CMakeLists.txt
+++ b/libcxx/modules/CMakeLists.txt
@@ -203,12 +203,23 @@ add_custom_target(generate-cxx-modules
     ${_all_modules}
 )
 
+
+function(make_absolute OUT_VAR INPUT BASE)
+  if (IS_ABSOLUTE ${INPUT})
+    set(${OUT_VAR} "${INPUT}" PARENT_SCOPE)
+  else()
+    set(${OUT_VAR} "${BASE}/${INPUT}" PARENT_SCOPE)
+  endif()
+endfunction()
+
 # Configure the modules manifest.
 # Use the relative path between the installation and the module in the json
 # file. This allows moving the entire installation to a different location.
+make_absolute(ABS_LIBRARY_DIR "${LIBCXX_INSTALL_LIBRARY_DIR}" "${CMAKE_INSTALL_PREFIX}")
+make_absolute(ABS_MODULES_DIR "${LIBCXX_INSTALL_MODULES_DIR}" "${CMAKE_INSTALL_PREFIX}")
 file(RELATIVE_PATH LIBCXX_MODULE_RELATIVE_PATH
-  ${CMAKE_INSTALL_PREFIX}/${LIBCXX_INSTALL_LIBRARY_DIR}
-  ${CMAKE_INSTALL_PREFIX}/${LIBCXX_INSTALL_MODULES_DIR})
+  ${ABS_LIBRARY_DIR}
+  ${ABS_MODULES_DIR})
 configure_file(
   "modules.json.in"
   "${LIBCXX_LIBRARY_DIR}/libc++.modules.json"

``````````

</details>


https://github.com/llvm/llvm-project/pull/85756