OS X: Detect implicit linker framework search paths

Previously we hard-coded a list of implicit framework directories but
did not account for CMAKE_OSX_SYSROOT or for changes to the list across
OS X versions.  Instead we should automatically detect the framework
directories for the active toolchain.

The parent commit added the "-Wl,-v" option to ask "ld" to print its
implicit directories.  It displays a block such as:

 Framework search paths:
	/...

Parse this block to extract the list of framework directories.

Detection may fail on toolchains that do not list their framework
directories, such as older OS X linkers.  Always treat the paths

 <sdk>/Library/Frameworks
 <sdk>/System/Library/Frameworks
 <sdk>/Network/Library/Frameworks # Older OS X only
 /System/Library/Frameworks

as implicit.  Note that /System/Library/Frameworks should always be
considered implicit so that frameworks CMake finds there will not
override the SDK copies.

6 files changed, 50 insertions, 15 deletions

diff --git a/Modules/CMakeCCompiler.cmake.in b/Modules/CMakeCCompiler.cmake.in
index d74dcdc..c41adc9 100644
--- a/Modules/CMakeCCompiler.cmake.in
+++ b/Modules/CMakeCCompiler.cmake.in
@@ -50,6 +50,7 @@ endif()
 
 set(CMAKE_C_IMPLICIT_LINK_LIBRARIES "@CMAKE_C_IMPLICIT_LINK_LIBRARIES@")
 set(CMAKE_C_IMPLICIT_LINK_DIRECTORIES "@CMAKE_C_IMPLICIT_LINK_DIRECTORIES@")
+set(CMAKE_C_IMPLICIT_LINK_FRAMEWORK_DIRECTORIES "@CMAKE_C_IMPLICIT_LINK_FRAMEWORK_DIRECTORIES@")
 
 @SET_CMAKE_CMCLDEPS_EXECUTABLE@
 @SET_CMAKE_CL_SHOWINCLUDE_PREFIX@
diff --git a/Modules/CMakeCXXCompiler.cmake.in b/Modules/CMakeCXXCompiler.cmake.in
index 8c5d84e..9287b81 100644
--- a/Modules/CMakeCXXCompiler.cmake.in
+++ b/Modules/CMakeCXXCompiler.cmake.in
@@ -51,6 +51,7 @@ endif()
 
 set(CMAKE_CXX_IMPLICIT_LINK_LIBRARIES "@CMAKE_CXX_IMPLICIT_LINK_LIBRARIES@")
 set(CMAKE_CXX_IMPLICIT_LINK_DIRECTORIES "@CMAKE_CXX_IMPLICIT_LINK_DIRECTORIES@")
+set(CMAKE_CXX_IMPLICIT_LINK_FRAMEWORK_DIRECTORIES "@CMAKE_CXX_IMPLICIT_LINK_FRAMEWORK_DIRECTORIES@")
 
 @SET_CMAKE_CMCLDEPS_EXECUTABLE@
 @SET_CMAKE_CL_SHOWINCLUDE_PREFIX@
diff --git a/Modules/CMakeDetermineCompilerABI.cmake b/Modules/CMakeDetermineCompilerABI.cmake
index cb94aa6..25d6bbe 100644
--- a/Modules/CMakeDetermineCompilerABI.cmake
+++ b/Modules/CMakeDetermineCompilerABI.cmake
@@ -72,8 +72,9 @@ function(CMAKE_DETERMINE_COMPILER_ABI lang src)
       # Parse implicit linker information for this language, if available.
       set(implicit_dirs "")
       set(implicit_libs "")
+      set(implicit_fwks "")
       if(CMAKE_${lang}_VERBOSE_FLAG)
-        CMAKE_PARSE_IMPLICIT_LINK_INFO("${OUTPUT}" implicit_libs implicit_dirs log
+        CMAKE_PARSE_IMPLICIT_LINK_INFO("${OUTPUT}" implicit_libs implicit_dirs implicit_fwks log
           "${CMAKE_${lang}_IMPLICIT_OBJECT_REGEX}")
         file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeOutput.log
           "Parsed ${lang} implicit link information from above output:\n${log}\n\n")
@@ -111,6 +112,7 @@ function(CMAKE_DETERMINE_COMPILER_ABI lang src)
 
       set(CMAKE_${lang}_IMPLICIT_LINK_LIBRARIES "${implicit_libs}" PARENT_SCOPE)
       set(CMAKE_${lang}_IMPLICIT_LINK_DIRECTORIES "${implicit_dirs}" PARENT_SCOPE)
+      set(CMAKE_${lang}_IMPLICIT_LINK_FRAMEWORK_DIRECTORIES "${implicit_fwks}" PARENT_SCOPE)
 
       # Detect library architecture directory name.
       if(CMAKE_LIBRARY_ARCHITECTURE_REGEX)
diff --git a/Modules/CMakeFortranCompiler.cmake.in b/Modules/CMakeFortranCompiler.cmake.in
index 55f8277..d193881 100644
--- a/Modules/CMakeFortranCompiler.cmake.in
+++ b/Modules/CMakeFortranCompiler.cmake.in
@@ -52,3 +52,4 @@ endif()
 
 set(CMAKE_Fortran_IMPLICIT_LINK_LIBRARIES "@CMAKE_Fortran_IMPLICIT_LINK_LIBRARIES@")
 set(CMAKE_Fortran_IMPLICIT_LINK_DIRECTORIES "@CMAKE_Fortran_IMPLICIT_LINK_DIRECTORIES@")
+set(CMAKE_Fortran_IMPLICIT_LINK_FRAMEWORK_DIRECTORIES "@CMAKE_Fortran_IMPLICIT_LINK_FRAMEWORK_DIRECTORIES@")
diff --git a/Modules/CMakeParseImplicitLinkInfo.cmake b/Modules/CMakeParseImplicitLinkInfo.cmake
index 54e8127..234fb7f 100644
--- a/Modules/CMakeParseImplicitLinkInfo.cmake
+++ b/Modules/CMakeParseImplicitLinkInfo.cmake
@@ -16,9 +16,10 @@
 # This is used internally by CMake and should not be included by user
 # code.
 
-function(CMAKE_PARSE_IMPLICIT_LINK_INFO text lib_var dir_var log_var obj_regex)
+function(CMAKE_PARSE_IMPLICIT_LINK_INFO text lib_var dir_var fwk_var log_var obj_regex)
   set(implicit_libs_tmp "")
   set(implicit_dirs_tmp)
+  set(implicit_fwks_tmp)
   set(log "")
 
   # Parse implicit linker arguments.
@@ -113,6 +114,11 @@ function(CMAKE_PARSE_IMPLICIT_LINK_INFO text lib_var dir_var log_var obj_regex)
     set(log "${log}  Library search paths: [${implicit_dirs_match}]\n")
     list(APPEND implicit_dirs_tmp ${implicit_dirs_match})
   endif()
+  if("${output_lines}" MATCHES ";Framework search paths:((;\t[^;]+)+)")
+    string(REPLACE ";\t" ";" implicit_fwks_match "${CMAKE_MATCH_1}")
+    set(log "${log}  Framework search paths: [${implicit_fwks_match}]\n")
+    list(APPEND implicit_fwks_tmp ${implicit_fwks_match})
+  endif()
 
   # Cleanup list of libraries and flags.
   # We remove items that are not language-specific.
@@ -125,27 +131,33 @@ function(CMAKE_PARSE_IMPLICIT_LINK_INFO text lib_var dir_var log_var obj_regex)
     endif()
   endforeach()
 
-  # Cleanup list of library directories.
-  set(implicit_dirs "")
-  foreach(d IN LISTS implicit_dirs_tmp)
-    get_filename_component(dir "${d}" ABSOLUTE)
-    string(FIND "${dir}" "${CMAKE_FILES_DIRECTORY}/" pos)
-    if(NOT pos LESS 0)
-      set(msg ", skipping non-system directory")
-    else()
-      set(msg "")
-      list(APPEND implicit_dirs "${dir}")
-    endif()
-    set(log "${log}  collapse library dir [${d}] ==> [${dir}]${msg}\n")
+  # Cleanup list of library and framework directories.
+  set(desc_dirs "library")
+  set(desc_fwks "framework")
+  foreach(t dirs fwks)
+    set(implicit_${t} "")
+    foreach(d IN LISTS implicit_${t}_tmp)
+      get_filename_component(dir "${d}" ABSOLUTE)
+      string(FIND "${dir}" "${CMAKE_FILES_DIRECTORY}/" pos)
+      if(NOT pos LESS 0)
+        set(msg ", skipping non-system directory")
+      else()
+        set(msg "")
+        list(APPEND implicit_${t} "${dir}")
+      endif()
+      set(log "${log}  collapse ${desc_${t}} dir [${d}] ==> [${dir}]${msg}\n")
+    endforeach()
+    list(REMOVE_DUPLICATES implicit_${t})
   endforeach()
-  list(REMOVE_DUPLICATES implicit_dirs)
 
   # Log results.
   set(log "${log}  implicit libs: [${implicit_libs}]\n")
   set(log "${log}  implicit dirs: [${implicit_dirs}]\n")
+  set(log "${log}  implicit fwks: [${implicit_fwks}]\n")
 
   # Return results.
   set(${lib_var} "${implicit_libs}" PARENT_SCOPE)
   set(${dir_var} "${implicit_dirs}" PARENT_SCOPE)
+  set(${fwk_var} "${implicit_fwks}" PARENT_SCOPE)
   set(${log_var} "${log}" PARENT_SCOPE)
 endfunction()
diff --git a/Modules/Platform/Darwin.cmake b/Modules/Platform/Darwin.cmake
index ed0b8af..2e6b71e 100644
--- a/Modules/Platform/Darwin.cmake
+++ b/Modules/Platform/Darwin.cmake
@@ -256,6 +256,24 @@ set(CMAKE_CXX_CREATE_MACOSX_FRAMEWORK
 if(NOT DEFINED CMAKE_FIND_FRAMEWORK)
   set(CMAKE_FIND_FRAMEWORK FIRST)
 endif()
+
+# Older OS X linkers do not report their framework search path
+# with -v but "man ld" documents the following locations.
+set(CMAKE_PLATFORM_IMPLICIT_LINK_FRAMEWORK_DIRECTORIES
+  ${_CMAKE_OSX_SYSROOT_PATH}/Library/Frameworks
+  ${_CMAKE_OSX_SYSROOT_PATH}/System/Library/Frameworks
+  )
+if(_CMAKE_OSX_SYSROOT_PATH)
+  # Treat some paths as implicit so we do not override the SDK versions.
+  list(APPEND CMAKE_PLATFORM_IMPLICIT_LINK_FRAMEWORK_DIRECTORIES
+    /System/Library/Frameworks)
+endif()
+if("${_CURRENT_OSX_VERSION}" VERSION_LESS "10.5")
+  # Older OS X tools had more implicit paths.
+  list(APPEND CMAKE_PLATFORM_IMPLICIT_LINK_FRAMEWORK_DIRECTORIES
+    ${_CMAKE_OSX_SYSROOT_PATH}/Network/Library/Frameworks)
+endif()
+
 # set up the default search directories for frameworks
 set(CMAKE_SYSTEM_FRAMEWORK_PATH
   ~/Library/Frameworks