[cfe-dev] CMake CACHE variables heads-up for 3.4

[Alp Toker]

Hello,

You may have noticed CMake-built versions of clang with unusual
executable versions, for example a current TOT clang just got built as
clang-3.2/libclang.3.2.dylib and another machine tracking LLVM SVN head
is getting built under bin/clang-3.3 even after make clean.

This seems to have been causing confusion in LLVM.org bug reports for
some time..

It turns out this happens because CLANG_EXECUTABLE_VERSION is set as a
CACHE variable in CMakeLists.txt. So value gets cached to whatever the
version was the *first time* you built LLVM and arbitrarily persists
through version upgrades -- probably not what anyone wants. Likewise the
libclang shared objects will get installed using whatever this value is
in your cache.

I'm planning to make at least CLANG_EXECUTABLE_VERSION and
LIBCLANG_LIBRARY_VERSION ordinary CMake variables in time for the new
release. This means if you're tracking LLVM 3.4 and relying on (or
shipping!) the binary installed as clang-3.1, clang-3.2 or clang-3.3
it's now going to change to clang-3.4 in line with the configure-based
system.

You'll still be able to tweak all the variables for your custom vendor
distribution as usual using -DCLANG_EXECUTABLE_VERSION etc. or with the
CMake GUI -- this change will just remove the hidden storage, but I
wanted to give a heads up in case anyone is relying on that behaviour.

Incidentally there are various other CACHE variables in LLVM's build
system, but they seem less problematic..


CMakeLists.txt:  set(CLANG_PATH_TO_LLVM_SOURCE "" CACHE PATH
CMakeLists.txt-    "Path to LLVM source code. Not necessary if using an
installed LLVM.")
CMakeLists.txt:  set(CLANG_PATH_TO_LLVM_BUILD "" CACHE PATH
CMakeLists.txt-    "Path to the directory where LLVM was built or
installed.")
CMakeLists.txt-
--
CMakeLists.txt-    set(LIT_ARGS_DEFAULT "${LIT_ARGS_DEFAULT}
--no-progress-bar")
CMakeLists.txt-  endif()
CMakeLists.txt:  set(LLVM_LIT_ARGS "${LIT_ARGS_DEFAULT}" CACHE STRING
"Default options for lit")
CMakeLists.txt-
CMakeLists.txt-  set( CMAKE_RUNTIME_OUTPUT_DIRECTORY
${CMAKE_BINARY_DIR}/bin )
--
CMakeLists.txt-endif()
CMakeLists.txt-
CMakeLists.txt:set(CLANG_RESOURCE_DIR "" CACHE STRING
CMakeLists.txt-  "Relative directory from the Clang binary to its
resource files.")
CMakeLists.txt-
CMakeLists.txt:set(C_INCLUDE_DIRS "" CACHE STRING
CMakeLists.txt-  "Colon separated list of directories clang will search
for headers.")
CMakeLists.txt-
CMakeLists.txt:set(GCC_INSTALL_PREFIX "" CACHE PATH "Directory where gcc
is installed." )
CMakeLists.txt:set(DEFAULT_SYSROOT "" CACHE PATH
CMakeLists.txt-  "Default <path> to all compiler invocations for
--sysroot=<path>." )
CMakeLists.txt-
CMakeLists.txt:set(CLANG_VENDOR "" CACHE STRING
CMakeLists.txt-  "Vendor-specific text for showing with version
information.")
CMakeLists.txt-
--
CMakeLists.txt-endif()
CMakeLists.txt-
CMakeLists.txt:set(CLANG_REPOSITORY_STRING "" CACHE STRING
CMakeLists.txt-  "Vendor-specific text for showing the repository the
source is taken from.")
CMakeLists.txt-
--
CMakeLists.txt-endif()
CMakeLists.txt-
CMakeLists.txt:set(CLANG_VENDOR_UTI "org.llvm.clang" CACHE STRING
CMakeLists.txt-  "Vendor-specific uti.")
CMakeLists.txt-
--
CMakeLists.txt-# Clang version information
CMakeLists.txt-set(CLANG_EXECUTABLE_VERSION
CMakeLists.txt:     "${CLANG_VERSION_MAJOR}.${CLANG_VERSION_MINOR}"
CACHE STRING
CMakeLists.txt-    "Version number that will be placed into the clang
executable, in the form XX.YY")
CMakeLists.txt-set(LIBCLANG_LIBRARY_VERSION
CMakeLists.txt:     "${CLANG_VERSION_MAJOR}.${CLANG_VERSION_MINOR}"
CACHE STRING
CMakeLists.txt-    "Version number that will be placed into the libclang
library , in the form XX.YY")
CMakeLists.txt-mark_as_advanced(CLANG_EXECUTABLE_VERSION
LIBCLANG_LIBRARY_VERSION)
--
CMakeLists.txt-endif()
CMakeLists.txt-
CMakeLists.txt:set(BUG_REPORT_URL "http://llvm.org/bugs/" CACHE STRING
CMakeLists.txt-  "Default URL where bug reports are to be submitted.")
CMakeLists.txt-
CMakeLists.txt:set(CLANG_ORDER_FILE "" CACHE FILEPATH
CMakeLists.txt-  "Order file to use when compiling clang in order to
improve startup time.")


Alp.


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