[CMake] Bug 25059 - CMake libllvm.so.$MAJOR.$MINOR shared object name not compatible with ldconfig

[beanz]

Summary

This change makes the CMake build system generate libraries for Linux and Darwin matching the makefile build system.

Linux libraries follow the pattern lib${name}.${MAJOR}.${MINOR}.so so that ldconfig won't pick it up incorrectly.

Darwin libraries are not versioned.

Note: On linux the non-versioned symlink is generated at install-time not build time. I plan to fix that eventually, but I expect that is good enough for the purposes of fixing this bug.

[• tstellarAMD]

This change makes the CMake build system generate libraries for Linux and Darwin matching the makefile build system.

The shared object name for cmake with this patch is still a little different from autoconf:

autoconf: libLLVM-3.8svn.so
cmake: libLLVM.3.8.so

autoconf also creates a symlink with the stable release number: libLLVM-3.8.0svn -> libLLVM.3.8svn.so

[beanz]

Updates based on feedback from Tom and a bug fix for installing the symlinks. Turns out I need to add the symlink install actions after the library is installed otherwise the cmake commands to make the links fails.

With this change the output lib directory has these files:
-rwxr-xr-x 1 cbieneman staff 40585176 Oct 19 13:22 libLLVM-3.8.0svn.dylib
lrwxr-xr-x 1 cbieneman staff 16 Oct 19 13:37 libLLVM.dylib -> libLLVM3.8.dylib
lrwxr-xr-x 1 cbieneman staff 22 Oct 19 13:37 libLLVM3.8.dylib -> libLLVM-3.8.0svn.dylib

[• tstellarAMD]

I've tested this and it resolves my issues. Thanks.

[axw]

cmake/modules/AddLLVM.cmake

555–557

Setting NO_SONAME means SONAME isn't set *at all*, which doesn't seem desirable.

$ objdump -p lib/libLLVM-3.8.0svn.so  | grep -c SONAME
0

That doesn't seem desirable. I would expect to see the SONAME set to the same as the output name. I think you just want to not set SOVERSION/VERSION instead? Did you mean to set NO_SONAME only for Apple?

[beanz]

• Fixed setting the SONAME in the binary on Linux
• Make SONAME goop optional, in autoconf we only apply it to libLLVM, not any of the other libraries

It is my belief that this patch makes our output on Linux and Darwin match autoconf.

[axw]

In an autoconf build I get:

libLLVM-3.8.0svn.so -> libLLVM-3.8svn.so
libLLVM-3.8svn.so
(SONAME: libLLVM-3.8svn.so)

With this patch, in a CMake build I get:

libLLVM-3.8.0svn.so
libLLVM3.8.so -> libLLVM-3.8.0svn.so
libLLVM.so -> libLLVM3.8.so
(SONAME: libLLVM-3.8.0svn.so)

I think what you should do is

• change api_name to: set(api_name ${name}-${LLVM_VERSION_MAJOR}.${LLVM_VERSION_MINOR}${LLVM_VERSION_SUFFIX})
• set OUTPUT_NAME to ${api_name}
• use ${api_name} in the -Wl,--soname flag
• switch the order of ${api_name} and ${library_name} in the first llvm_install_library_symlink

Making these changes locally, I get:

libLLVM-3.8.0svn.so -> libLLVM-3.8svn.so
libLLVM-3.8svn.so
libLLVM.so -> libLLVM-3.8svn.so
(SONAME: libLLVM-3.8svn.so)

which is exactly the same as autoconf, but with the extra libLLVM.so symlink.

Do we still need to set SOVERSION/VERSION in llvm_add_library?

cmake/modules/AddLLVM.cmake

563

setting LINK_FLAGS needs a separate set_target_properties with APPEND_STRING

[beanz]

Feedback and fixes based on feedback from axw.

• Properly setting LINK_FLAGS
• Not setting VERSION or SOVERSION, this also means I don't need to set NO_SONAME
• Re-structuring the symlink magic to actually match autoconf this time

[axw]

cmake/modules/AddLLVM.cmake

559

Sorry, I actually meant to delete the comment about APPEND_STRING. I think set_target_properties' LINK_FLAGS is a special case.

Anyway, it turns out you can just delete this. If you don't specify SOVERSION, VERSION or NO_SONAME, CMake automatically set SONAME to the same as the output name.

LGTM with this last change. Thank you.

[loladiro]

I realize I may have missed my window of opportunity here, but do the Mac shared lib names no longer include the version? When I build a recent LLVM, I only get libLLVM.dylib, without any version numbers or even symlinks. Was that intentional?

cmake/modules/AddLLVM.cmake

if(ARG_SHARED AND ARG_STATIC)
     set(ARG_STATIC)
   endif()
 
   if(ARG_MODULE)
     add_library(${name} MODULE ${ALL_FILES})
   elseif(ARG_SHARED)
     add_windows_version_resource_file(ALL_FILES ${ALL_FILES})
     add_library(${name} SHARED ${ALL_FILES})
+    if(UNIX)
+      # Disable CMake's builtin SO versioning. Historically LLVM hasn't used so
+      # versioning on Darwin, and linux so versioning is hand-rolled.
+      set_target_properties(${name} PROPERTIES NO_SONAME On)
+      if(NOT APPLE)
+        set(library_name ${name}.${LLVM_VERSION_MAJOR}.${LLVM_VERSION_MINOR})
+        set_target_properties(${name} PROPERTIES OUTPUT_NAME ${library_name})
+        llvm_install_library_symlink(${name} ${library_name} SHARED ALWAYS_GENERATE)
+      endif()
+    endif()
   else()
     add_library(${name} STATIC ${ALL_FILES})
   endif()
 
   if(DEFINED windows_resource_file)
     set_windows_version_resource_properties(${name} ${windows_resource_file})
     set(windows_resource_file ${windows_resource_file} PARENT_SCOPE)
   endif()
if(ARG_SHARED)
     if(WIN32)
       set_target_properties(${name} PROPERTIES
         PREFIX ""
         )
     endif()
 
     set_target_properties(${name}
       PROPERTIES
-      SOVERSION ${LLVM_VERSION_MAJOR}.${LLVM_VERSION_MINOR}
       VERSION ${LLVM_VERSION_MAJOR}.${LLVM_VERSION_MINOR}.${LLVM_VERSION_PATCH}${LLVM_VERSION_SUFFIX})
   endif()
 
   if(ARG_MODULE OR ARG_SHARED)
     # Do not add -Dname_EXPORTS to the command-line when building files in this
     # target. Doing so is actively harmful for the modules build because it
     # creates extra module variants, and not useful because we don't use these
     # macros.
if (NOT LLVM_INSTALL_TOOLCHAIN_ONLY OR ${name} STREQUAL "LTO")
       if (NOT CMAKE_CONFIGURATION_TYPES)
         add_custom_target(install-${name}
                           DEPENDS ${name}
                           COMMAND "${CMAKE_COMMAND}"
                                   -DCMAKE_INSTALL_COMPONENT=${name}
                                   -P "${CMAKE_BINARY_DIR}/cmake_install.cmake")
       endif()
     endif()
     set_property(GLOBAL APPEND PROPERTY LLVM_EXPORTS ${name})
   endif()
   set_target_properties(${name} PROPERTIES FOLDER "Libraries")
 endmacro(add_llvm_library name)
 
 macro(add_llvm_loadable_module name)
   llvm_add_library(${name} MODULE ${ARGN})
   if(NOT TARGET ${name})
     # Add empty "phony" target
     add_custom_target(${name})
   else()
     if( EXCLUDE_FROM_ALL )
       set_target_properties( ${name} PROPERTIES EXCLUDE_FROM_ALL ON)
     else()
       if (NOT LLVM_INSTALL_TOOLCHAIN_ONLY)
         if(WIN32 OR CYGWIN)
           # DLL platform
foreach(dir ${lit_suites})
           DEPENDS ${ARG_DEPENDS}
           ARGS ${ARG_ARGS}
         )
       endif()
     endforeach()
   endif()
 endfunction()
 
+function(llvm_install_library_symlink name dest type)
+  cmake_parse_arguments(ARG "ALWAYS_GENERATE" "" "" ${ARGN})
+  foreach(path ${CMAKE_MODULE_PATH})
+    if(EXISTS ${path}/LLVMInstallSymlink.cmake)
+      set(INSTALL_SYMLINK ${path}/LLVMInstallSymlink.cmake)
+      break()
+    endif()
+  endforeach()
+  
+  set(component ${name})
+
+  set(full_name ${CMAKE_${type}_LIBRARY_PREFIX}${name}${CMAKE_${type}_LIBRARY_SUFFIX})
+  set(full_dest ${CMAKE_${type}_LIBRARY_PREFIX}${dest}${CMAKE_${type}_LIBRARY_SUFFIX})
+
+  set(output_dir lib)
+  if(WIN32 AND "${type}" STREQUAL "SHARED")
+    set(output_dir bin)
+  endif()
+
+  install(SCRIPT ${INSTALL_SYMLINK}
+          CODE "install_symlink(${full_name} ${full_dest} ${output_dir})"
+          COMPONENT ${component})
+
+  if (NOT CMAKE_CONFIGURATION_TYPES AND NOT ARG_ALWAYS_GENERATE)
+    add_custom_target(install-${name}
+                      DEPENDS ${name} ${dest} install-${dest}
+                      COMMAND "${CMAKE_COMMAND}"
+                              -DCMAKE_INSTALL_COMPONENT=${name}
+                              -P "${CMAKE_BINARY_DIR}/cmake_install.cmake")
+  endif()
+endfunction()
+
 function(llvm_install_symlink name dest)
   cmake_parse_arguments(ARG "ALWAYS_GENERATE" "" "" ${ARGN})
   foreach(path ${CMAKE_MODULE_PATH})
     if(EXISTS ${path}/LLVMInstallSymlink.cmake)
       set(INSTALL_SYMLINK ${path}/LLVMInstallSymlink.cmake)
       break()
     endif()
   endforeach()