build: CMake caching failing PIE check #32323

1. 
   fanquake commented at 10:43 am on April 22, 2025: member

   Similar to #31942 (comment), CMake caches the check failure, which leaves the user in a broken state (unless they nuke the build dir):

    0cmake -B build -DAPPEND_CXXFLAGS="-ftrivial-auto-var-init"
    1-- The CXX compiler identification is GNU 14.2.0
    2-- Detecting CXX compiler ABI info
    3-- Detecting CXX compiler ABI info - done
    4-- Check for working CXX compiler: /usr/bin/c++ - skipped
    5-- Detecting CXX compile features
    6-- Detecting CXX compile features - done
    7-- Setting build type to "RelWithDebInfo" as none was specified
    8-- Performing Test CXX_SUPPORTS__WERROR
    9-- Performing Test CXX_SUPPORTS__WERROR - Success
   10-- Performing Test CXX_SUPPORTS__G3
   11-- Performing Test CXX_SUPPORTS__G3 - Success
   12-- Performing Test LINKER_SUPPORTS__G3
   13-- Performing Test LINKER_SUPPORTS__G3 - Success
   14-- Performing Test CXX_SUPPORTS__FTRAPV
   15-- Performing Test CXX_SUPPORTS__FTRAPV - Success
   16-- Performing Test LINKER_SUPPORTS__FTRAPV
   17-- Performing Test LINKER_SUPPORTS__FTRAPV - Success
   18-- Found SQLite3: /usr/include (found suitable version "3.45.1", minimum required is "3.7.17") 
   19CMake Warning at cmake/module/CheckLinkerSupportsPIE.cmake:24 (message):
   20  PIE is not supported at link time.  See the configure log for details.
   21Call Stack (most recent call first):
   22  CMakeLists.txt:203 (check_linker_supports_pie)
   23
   24
   25-- Performing Test LINKER_SUPPORTS__WL___FATAL_WARNINGS
   26-- Performing Test LINKER_SUPPORTS__WL___FATAL_WARNINGS - Failed
   27-- Performing Test CMAKE_HAVE_LIBC_PTHREAD
   28-- Performing Test CMAKE_HAVE_LIBC_PTHREAD - Failed
   29-- Check if compiler accepts -pthread
   30-- Check if compiler accepts -pthread - no
   31-- Looking for pthread_create in pthreads
   32-- Looking for pthread_create in pthreads - not found
   33-- Looking for pthread_create in pthread
   34-- Looking for pthread_create in pthread - not found
   35CMake Error at /usr/share/cmake-3.28/Modules/FindPackageHandleStandardArgs.cmake:230 (message):
   36  Could NOT find Threads (missing: Threads_FOUND)
   37Call Stack (most recent call first):
   38  /usr/share/cmake-3.28/Modules/FindPackageHandleStandardArgs.cmake:600 (_FPHSA_FAILURE_MESSAGE)
   39  /usr/share/cmake-3.28/Modules/FindThreads.cmake:226 (FIND_PACKAGE_HANDLE_STANDARD_ARGS)
   40  CMakeLists.txt:345 (find_package)
   41
   42
   43-- Configuring incomplete, errors occurred!
   

   Fix the compiler flag (forgot the =zero), and reconfigure:

    0 cmake -B build -DAPPEND_CXXFLAGS="-ftrivial-auto-var-init=zero"
    1CMake Warning at cmake/module/CheckLinkerSupportsPIE.cmake:24 (message):
    2  PIE is not supported at link time.  See the configure log for details.
    3Call Stack (most recent call first):
    4  CMakeLists.txt:203 (check_linker_supports_pie)
    5
    6
    7CMake Error at /usr/share/cmake-3.28/Modules/FindPackageHandleStandardArgs.cmake:230 (message):
    8  Could NOT find Threads (missing: Threads_FOUND)
    9Call Stack (most recent call first):
   10  /usr/share/cmake-3.28/Modules/FindPackageHandleStandardArgs.cmake:600 (_FPHSA_FAILURE_MESSAGE)
   11  /usr/share/cmake-3.28/Modules/FindThreads.cmake:226 (FIND_PACKAGE_HANDLE_STANDARD_ARGS)
   12  CMakeLists.txt:345 (find_package)
   13
   14
   15-- Configuring incomplete, errors occurred!
   

2. hebasto added the label Build system on Apr 22, 2025
3. 
   hebasto commented at 8:18 pm on April 26, 2025: member

   Quoting from #31942 (comment):

   … a recommended debugging step is to discard any cached results from an existing build directory…

   And in this particular case, I don’t think that the CMake cache is worth reusing.

4. 
   fanquake commented at 9:07 am on April 28, 2025: member

   Not sure I understand your suggestion; are you saying we don’t fix this? Are you saying we should add a recommendation to the build docs to always delete the build dir before running CMake? Something else? Note that this is a generic issue, and the PIE check is just the first check that fails in this way, if you remove the PIE check the threads check will fail the same.
5. 
   hebasto commented at 9:38 am on April 28, 2025: member

   are you saying we don’t fix this?

   Correct. UPD.: #32323 (comment)

   Are you saying we should add a recommendation to the build docs to always delete the build dir before running CMake? Something else?

   Not “always” — only when configuration fails. Similar to #31942 (comment).

6. 
   hebasto commented at 4:37 pm on April 28, 2025: member

   After further consideration, I believe this issue exposes a bug that is fixed in #32367.

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