Add minor version to libclang.so and libclang-cpp.so SONAME

[tstellar]

Summary

This patch is for the release/11.x branch. We need to bump the SONAME, because
the ABI of the shared library is changing

[dim]

@sylvestre.ledru removed the minor version from the binary (on purpose, I think?) in rGa8b717fda42294d1c8e1f05d71280503e5839f14:

commit a8b717fda42294d1c8e1f05d71280503e5839f14
Author: Sylvestre Ledru <[e-mail]>
Date:   Thu Mar 29 10:05:46 2018 +0000

    Rename clang link from clang-X.Y to clang-X

    Summary:
    As we are only doing X.0.Z releases (not using the minor version), there is no need to keep -X.Y in the version.
    So, instead, I propose the following:
    Instead of having clang-7.0 in bin/, we will have clang-7

    Since also matches was gcc is doing.

    Reviewers: tstellar, dlj, dim, hans

    Reviewed By: dim, hans

    Subscribers: dim, mgorny, cfe-commits

    Differential Revision: https://reviews.llvm.org/D41808

    llvm-svn: 328769

But this seems to have been mainly about the clang executable that gets installed into $prefix/bin, i.e. clang-11 instead of clang-11.1.

I think this doesn't matter for the clang executable here, since nobody uses its ABI. But indeed for the shared library it looks like a good solution, if you would want to install both versions side-by-side.

[sylvestre.ledru]

I might be wrong but if the ABI is incompatible, are we not supposed to update the SONAME itself?

[tstellar]

In D94941#2509829, @sylvestre.ledru wrote:

I might be wrong but if the ABI is incompatible, are we not supposed to update the SONAME itself?

That's what this patch does, it updates the SONAME from *-11 to *-11.1.

[sylvestre.ledru]

Yeah, my question is more "is that enough for distro?"
https://www.debian.org/doc/manuals/maint-guide/advanced.en.html
https://www.gnu.org/software/libtool/manual/html_node/Updating-version-info.html

I might be wrong but if 11.1 and 11.0 aren't compatible (not just adding a new function), I was wondering if if should not be 12 (I know it is terrible).
Maybe we can expect that packagers will know that 11.1 is like a 12 in term of soname

[cuviper]

If the SONAME is different in any way, it is totally distinct to the dynamic linker. There's no semver parsing or anything like that. That's all we can do from a technical perspective, and the rest is just communication in the release.

[sylvestre.ledru]

Let's do it then :)

[sylvestre.ledru]

I guess this will be clearly mentioned in the release notes :)

[cuviper]

clang/tools/clang-shlib/CMakeLists.txt

54

I think you also need VERSION here, or else it symlinks back to .so.11.

[tstellar]

clang/tools/clang-shlib/CMakeLists.txt

54

I think add_clang_library is setting VERSION. This is what I get when I build:

lib/libclang-cpp.so -> libclang-cpp.so.11.1
lib/libclang.so -> libclang.so.11.1

[cuviper]

clang/tools/clang-shlib/CMakeLists.txt

54

I see those links, but also lib/libclang-cpp.so.11.1 -> libclang-cpp.so.11, with the latter being the real file. If I add VERSION explicitly, that goes away.
(I had to delete lib/libclang*.so* before rebuilding too.)

[tstellar]

clang/tools/clang-shlib/CMakeLists.txt

54

OK, I see it now. I can fix that.

[tstellar]

Fix shared object symlinks.

clang/CMakeLists.txt

if(CLANG_ENABLE_ARCMT)
   set(CLANG_ENABLE_OBJC_REWRITER ON)
 endif()
 
 # Clang version information
 set(CLANG_EXECUTABLE_VERSION
     "${CLANG_VERSION_MAJOR}" CACHE STRING
     "Major version number that will be appended to the clang executable name")
 set(LIBCLANG_LIBRARY_VERSION
-    "${CLANG_VERSION_MAJOR}" CACHE STRING
+    "${CLANG_VERSION_MAJOR}.${CLANG_VERSION_MINOR}" CACHE STRING
     "Major version number that will be appended to the libclang library")
 mark_as_advanced(CLANG_EXECUTABLE_VERSION LIBCLANG_LIBRARY_VERSION)
 
 option(CLANG_INCLUDE_TESTS
        "Generate build targets for the Clang unit tests."
        ${LLVM_INCLUDE_TESTS})
 
 add_subdirectory(utils/TableGen)

clang/tools/clang-shlib/CMakeLists.txt

 
 add_clang_library(clang-cpp
                   SHARED
                   ${INSTALL_WITH_TOOLCHAIN}
                   clang-shlib.cpp
                   ${_OBJECTS}
                   LINK_LIBS
                   ${_DEPS})
+
+    set_target_properties(clang-cpp
+      PROPERTIES
+      VERSION ${LIBCLANG_LIBRARY_VERSION}
+      SOVERSION ${LIBCLANG_LIBRARY_VERSION})

clang/tools/libclang/CMakeLists.txt

elseif(APPLE)
     set(LIBCLANG_LINK_FLAGS " -Wl,-compatibility_version -Wl,1")
     set(LIBCLANG_LINK_FLAGS "${LIBCLANG_LINK_FLAGS} -Wl,-current_version -Wl,${LLVM_VERSION_MAJOR}.${LLVM_VERSION_MINOR}.${LLVM_VERSION_PATCH}")
 
     set_property(TARGET libclang APPEND_STRING PROPERTY
                  LINK_FLAGS ${LIBCLANG_LINK_FLAGS})
   else()
     set_target_properties(libclang
       PROPERTIES
+      SOVERSION ${LIBCLANG_LIBRARY_VERSION}
       VERSION ${LIBCLANG_LIBRARY_VERSION}
       DEFINE_SYMBOL _CINDEX_LIB_)
     # FIXME: _CINDEX_LIB_ affects dllexport/dllimport on Win32.
     if(LLVM_ENABLE_MODULES AND NOT WIN32)
       target_compile_options(libclang PRIVATE
         "-fmodules-ignore-macro=_CINDEX_LIB_"
         )
     endif()