[CMake] Pass symlink dependency to add_llvm_install_targets explicitly

[phosek]

Summary

The install-${name}-stripped targets don't strip when ${name} is being
symlinked, e.g. llvm-ar or llvm-objcopy. The problem is that
llvm_install_symlink passes install-${dest} as a dependency of
install-${name}, e.g. install-llvm-ar becomes a dependency of both
install-llvm-ranlib and install-llvm-ranlib-stripped. What this means is
that when installing a distribution that contains both llvm-ar and
llvm-ranlib is that first the stripped version of llvm-ar is installed
(by the install-llvm-ar-stripped target) and then it's overwritten by an
unstripped version of llvm-ar bnecause install-llvm-ranlib-stripped has
install-llvm-ranlib as a dependency as mentioned earlier. To avoid this
issue, rather than passing the install-${dest} as dependency, we
introduce a new argument to add_llvm_install_targets for symlink target
which expands it into an appropriate dependency, i.e. install-${dest}
for install-${name} target and install-${dest}-stripped for
install-${name}-stripped.

[phosek]

As an alternative, I've also considered iterating over all dependencies inside add_llvm_install_targets and see if the prefix of that target is install- and handling it specially, but that seems like a more error prone solution.

[phosek]

Ping?

[smeenai]

Sorry, was on vacation. Looks good, thanks!

llvm/cmake/modules/AddLLVM.cmake

if(ARG_STATIC AND LLVM_TOUCH_STATIC_LIBRARIES)
     add_custom_command(TARGET ${name}
       POST_BUILD
       COMMAND touch ${LLVM_LIBRARY_DIR}/${CMAKE_STATIC_LIBRARY_PREFIX}${name}${CMAKE_STATIC_LIBRARY_SUFFIX}
       )
   endif()
 endfunction()
 
 function(add_llvm_install_targets target)
-  cmake_parse_arguments(ARG "" "COMPONENT;PREFIX" "DEPENDS" ${ARGN})
+  cmake_parse_arguments(ARG "" "COMPONENT;PREFIX;SYMLINK" "DEPENDS" ${ARGN})
   if(ARG_COMPONENT)
     set(component_option -DCMAKE_INSTALL_COMPONENT="${ARG_COMPONENT}")
   endif()
   if(ARG_PREFIX)
     set(prefix_option -DCMAKE_INSTALL_PREFIX="${ARG_PREFIX}")
   endif()
 
   set(file_dependencies)
add_custom_target(${target}-stripped
                             ${prefix_option}
                             -DCMAKE_INSTALL_DO_STRIP=1
                             -P "${CMAKE_BINARY_DIR}/cmake_install.cmake"
                     USES_TERMINAL)
   if(target_dependencies)
     add_dependencies(${target} ${target_dependencies})
     add_dependencies(${target}-stripped ${target_dependencies})
   endif()
+
+  if(ARG_SYMLINK)
+    add_dependencies(${target} install-${ARG_SYMLINK})
+    add_dependencies(${target}-stripped install-${ARG_SYMLINK}-stripped)
+  endif()
 endfunction()
 
 function(add_llvm_component_library name)
   add_llvm_library(${name} COMPONENT_LIB ${ARGN})
 endfunction()
 
 macro(add_llvm_library name)
   cmake_parse_arguments(ARG
function(llvm_install_library_symlink name dest type)
   endif()
 
   install(SCRIPT ${INSTALL_SYMLINK}
           CODE "install_symlink(${full_name} ${full_dest} ${output_dir})"
           COMPONENT ${component})
 
   if (NOT LLVM_ENABLE_IDE AND NOT ARG_ALWAYS_GENERATE)
     add_llvm_install_targets(install-${name}
-                             DEPENDS ${name} ${dest} install-${dest}
-                             COMPONENT ${name})
+                             DEPENDS ${name} ${dest}
+                             COMPONENT ${name}
+                             SYMLINK ${dest})
   endif()
 endfunction()
 
 function(llvm_install_symlink name dest)
   cmake_parse_arguments(ARG "ALWAYS_GENERATE" "COMPONENT" "" ${ARGN})
   foreach(path ${CMAKE_MODULE_PATH})
     if(EXISTS ${path}/LLVMInstallSymlink.cmake)
       set(INSTALL_SYMLINK ${path}/LLVMInstallSymlink.cmake)
function(llvm_install_symlink name dest)
   set(full_dest ${dest}${CMAKE_EXECUTABLE_SUFFIX})
 
   install(SCRIPT ${INSTALL_SYMLINK}
           CODE "install_symlink(${full_name} ${full_dest} ${LLVM_TOOLS_INSTALL_DIR})"
           COMPONENT ${component})
 
   if (NOT LLVM_ENABLE_IDE AND NOT ARG_ALWAYS_GENERATE)
     add_llvm_install_targets(install-${name}
-                             DEPENDS ${name} ${dest} install-${dest}
-                             COMPONENT ${name})
+                             DEPENDS ${name} ${dest}
+                             COMPONENT ${name}
+                             SYMLINK ${dest})
   endif()
 endfunction()
 
 function(add_llvm_tool_symlink link_name target)
   cmake_parse_arguments(ARG "ALWAYS_GENERATE" "OUTPUT_DIR" "" ${ARGN})
   set(dest_binary "$<TARGET_FILE:${target}>")
 
   # This got a bit gross... For multi-configuration generators the target