[CMake] Pass symlink dependency to add_llvm_install_targets explicitly

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.

Differential Revision: https://reviews.llvm.org/D71951

llvm/cmake/modules/AddLLVM.cmake

@@ -642,7 +642,7 @@ function(llvm_add_library name)
 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()
@@ -679,6 +679,11 @@ function(add_llvm_install_targets target)
     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)
@@ -1627,8 +1632,9 @@ function(llvm_install_library_symlink name dest type)
 
   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()
 
@@ -1660,8 +1666,9 @@ function(llvm_install_symlink name dest)
 
   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()