file(GET_RUNTIME_DEPENDENCIES): Fix weak macOS libraries not detected

Starting with Clang 12, `otool -l` reports `LC_LOAD_WEAK_DYLIB` instead
of `LC_LOAD_DYLIB` for weakly linked libraries.  Update the
implementation of `file(GET_RUNTIME_DEPENDENCIES)` to recognize these.

Fixes: #21684

Source/cmBinUtilsMacOSMachOOToolGetRuntimeDependenciesTool.cxx

@@ -44,7 +44,7 @@ bool cmBinUtilsMacOSMachOOToolGetRuntimeDependenciesTool::GetFileInfo(
   std::string line;
   static const cmsys::RegularExpression rpathRegex("^ *cmd LC_RPATH$");
   static const cmsys::RegularExpression loadDylibRegex(
-    "^ *cmd LC_LOAD_DYLIB$");
+    "^ *cmd LC_LOAD(_WEAK)?_DYLIB$");
   static const cmsys::RegularExpression pathRegex(
     "^ *path (.*) \\(offset [0-9]+\\)$");
   static const cmsys::RegularExpression nameRegex(

Tests/RunCMake/file-GET_RUNTIME_DEPENDENCIES/macos-all-check.cmake

@@ -148,6 +148,27 @@ set(_check
   )
 check_contents(deps/udeps6.txt "^${_check}$")
 
+# Weak library reference should have exactly the same dependencies as a regular library reference (test 1)
+set_with_libsystem(_check
+  [[[^;]*/Tests/RunCMake/file-GET_RUNTIME_DEPENDENCIES/macos-build/root-all/executable/bin/../lib/executable_path/libexecutable_path\.dylib]]
+  [[[^;]*/Tests/RunCMake/file-GET_RUNTIME_DEPENDENCIES/macos-build/root-all/executable/bin/../lib/rpath_executable_path/librpath_executable_path\.dylib]]
+  [[[^;]*/Tests/RunCMake/file-GET_RUNTIME_DEPENDENCIES/macos-build/root-all/executable/lib/libtestlib\.dylib]]
+  [[[^;]*/Tests/RunCMake/file-GET_RUNTIME_DEPENDENCIES/macos-build/root-all/executable/lib/loader_path/libloader_path\.dylib]]
+  [[[^;]*/Tests/RunCMake/file-GET_RUNTIME_DEPENDENCIES/macos-build/root-all/executable/lib/normal/../rpath/librpath\.dylib]]
+  [[[^;]*/Tests/RunCMake/file-GET_RUNTIME_DEPENDENCIES/macos-build/root-all/executable/lib/normal/libnormal\.dylib]]
+  [[[^;]*/Tests/RunCMake/file-GET_RUNTIME_DEPENDENCIES/macos-build/root-all/executable/lib/rpath_loader_path/librpath_loader_path\.dylib]]
+  )
+check_contents(deps/deps7.txt "^${_check}$")
+
+set(_check
+  [[@executable_path/../lib/executable_path_bundle/libexecutable_path_bundle\.dylib]]
+  [[@loader_path/loader_path_unresolved/libloader_path_unresolved\.dylib]]
+  [[@rpath/librpath_executable_path_bundle\.dylib]]
+  [[@rpath/librpath_loader_path_unresolved\.dylib]]
+  [[@rpath/librpath_unresolved\.dylib]]
+  )
+check_contents(deps/udeps7.txt "^${_check}$")
+
 set(_check
   "^libconflict\\.dylib:[^;]*/Tests/RunCMake/file-GET_RUNTIME_DEPENDENCIES/macos-build/root-all/executable/lib/conflict/libconflict\\.dylib;[^;]*/Tests/RunCMake/file-GET_RUNTIME_DEPENDENCIES/macos-build/root-all/executable/lib/conflict2/libconflict\\.dylib\n$"
   )
@@ -157,3 +178,4 @@ check_contents(deps/cdeps3.txt "${_check}")
 check_contents(deps/cdeps4.txt "${_check}")
 check_contents(deps/cdeps5.txt "${_check}")
 check_contents(deps/cdeps6.txt "${_check}")
+check_contents(deps/cdeps7.txt "${_check}")

Tests/RunCMake/file-GET_RUNTIME_DEPENDENCIES/macos.cmake

@@ -128,16 +128,19 @@ endforeach()
 target_link_libraries(testlib PRIVATE ${testlib_names})
 
 add_executable(topexe macos/topexe.c)
+add_executable(topexe_weak macos/topexe.c)
 add_library(toplib SHARED macos/toplib.c)
 add_library(topmod MODULE macos/toplib.c)
 target_link_libraries(topexe PRIVATE testlib)
+target_link_libraries(topexe_weak PRIVATE "-weak_library" testlib)
 target_link_libraries(toplib PRIVATE testlib)
 target_link_libraries(topmod PRIVATE testlib)
 
 set_property(TARGET topexe toplib topmod PROPERTY INSTALL_RPATH "${CMAKE_BINARY_DIR}/root-all/executable/lib")
+set_property(TARGET topexe_weak toplib topmod PROPERTY INSTALL_RPATH "${CMAKE_BINARY_DIR}/root-all/executable/lib")
 
-install(TARGETS topexe toplib topmod testlib testlib_conflict RUNTIME DESTINATION executable/bin LIBRARY DESTINATION executable/lib)
-install(TARGETS topexe toplib topmod testlib testlib_conflict RUNTIME DESTINATION bundle_executable/bin LIBRARY DESTINATION bundle_executable/lib)
+install(TARGETS topexe topexe_weak toplib topmod testlib testlib_conflict RUNTIME DESTINATION executable/bin LIBRARY DESTINATION executable/lib)
+install(TARGETS topexe topexe_weak toplib topmod testlib testlib_conflict RUNTIME DESTINATION bundle_executable/bin LIBRARY DESTINATION bundle_executable/lib)
 
 install(CODE [[
   function(exec_get_runtime_dependencies depsfile udepsfile cdepsfile)
@@ -213,4 +216,12 @@ install(CODE [[
       "${CMAKE_INSTALL_PREFIX}/executable/lib/$<TARGET_FILE_NAME:testlib_conflict>"
     BUNDLE_EXECUTABLE "${CMAKE_INSTALL_PREFIX}/bundle_executable/bin/$<TARGET_FILE_NAME:topexe>"
     )
+
+  exec_get_runtime_dependencies(
+    deps7.txt udeps7.txt cdeps7.txt
+    EXECUTABLES
+      "${CMAKE_INSTALL_PREFIX}/executable/bin/$<TARGET_FILE_NAME:topexe_weak>"
+    LIBRARIES
+      "${CMAKE_INSTALL_PREFIX}/executable/lib/$<TARGET_FILE_NAME:testlib_conflict>"
+    )
   ]])