build: excise the concept of fat libraries

This was used for the swift-reflection-test tool.  Instead of using fat
binaries, use the target binary itself.  This simplifies the build logic
as well as paves the road to sub-builds for each target rather than a
monolithic build as we have today.

Originally, the swift-reflection-test was a host tool that linked
against the target libraries since it was testing the target layout.
Now that the tool has been split into a host and target component
(5ea5bb0) and we have target and host
libraries that we can link against appropriately, we do not need to link
against the FAT binary.  Since there was exactly one use of this
functionality, switching that from fat linking to regular linking allows
us to remove this functionality entirely.  Switch to regular linking and
remove the option.

Author: compnerd

cmake/modules/AddSwift.cmake

@@ -2104,15 +2104,12 @@ endfunction()
 #
 #   [ARCHITECTURE architecture]
 #     Architecture to build for.
-#
-#   [LINK_FAT_LIBRARIES lipo_target1 ...]
-#     Fat libraries to link with.
 function(_add_swift_executable_single name)
   # Parse the arguments we were given.
   cmake_parse_arguments(SWIFTEXE_SINGLE
     "EXCLUDE_FROM_ALL"
     "SDK;ARCHITECTURE"
-    "DEPENDS;LLVM_COMPONENT_DEPENDS;LINK_LIBRARIES;LINK_FAT_LIBRARIES;COMPILE_FLAGS"
+    "DEPENDS;LLVM_COMPONENT_DEPENDS;LINK_LIBRARIES;COMPILE_FLAGS"
     ${ARGN})
 
   set(SWIFTEXE_SINGLE_SOURCES ${SWIFTEXE_SINGLE_UNPARSED_ARGUMENTS})
@@ -2160,27 +2157,11 @@ function(_add_swift_executable_single name)
         "-Xlinker" "@executable_path/../lib/swift/${SWIFT_SDK_${SWIFTEXE_SINGLE_SDK}_LIB_SUBDIR}")
   endif()
 
-  # Find the names of dependency library targets.
-  #
-  # We don't add the ${ARCH} to the target suffix because we want to link
-  # against fat libraries.  This only works for the Darwin targets as MachO is
-  # the only format with the fat libraries.
-  if(${SWIFTEXE_SINGLE_SDK} IN_LIST SWIFT_APPLE_PLATFORMS)
-    _list_add_string_suffix(
-        "${SWIFTEXE_SINGLE_LINK_FAT_LIBRARIES}"
-        "-${SWIFT_SDK_${SWIFTEXE_SINGLE_SDK}_LIB_SUBDIR}"
-        SWIFTEXE_SINGLE_LINK_FAT_LIBRARIES_TARGETS)
-    _list_add_string_suffix(
-        "${SWIFTEXE_SINGLE_LINK_FAT_LIBRARIES}"
-        "-${SWIFT_SDK_${SWIFTEXE_SINGLE_SDK}_LIB_SUBDIR}-${SWIFTEXE_SINGLE_ARCHITECTURE}"
-        SWIFTEXE_SINGLE_LINK_FAT_LIBRARIES)
-  else()
-    _list_add_string_suffix(
-        "${SWIFTEXE_SINGLE_LINK_FAT_LIBRARIES}"
-        "-${SWIFT_SDK_${SWIFTEXE_SINGLE_SDK}_LIB_SUBDIR}-${SWIFTEXE_SINGLE_ARCHITECTURE}"
-        SWIFTEXE_SINGLE_LINK_FAT_LIBRARIES_TARGETS)
-    set(SWIFTEXE_SINGLE_LINK_FAT_LIBRARIES ${SWIFTEXE_SINGLE_LINK_FAT_LIBRARIES_TARGETS})
-  endif()
+  _list_add_string_suffix(
+      "${SWIFTEXE_SINGLE_LINK_LIBRARIES}"
+      "-${SWIFT_SDK_${SWIFTEXE_SINGLE_SDK}_LIB_SUBDIR}-${SWIFTEXE_SINGLE_ARCHITECTURE}"
+      SWIFTEXE_SINGLE_LINK_LIBRARIES_TARGETS)
+  set(SWIFTEXE_SINGLE_LINK_LIBRARIES ${SWIFTEXE_SINGLE_LINK_LIBRARIES_TARGETS})
 
   handle_swift_sources(
       dependency_target
@@ -2191,7 +2172,6 @@ function(_add_swift_executable_single name)
       SWIFTEXE_SINGLE_SOURCES SWIFTEXE_SINGLE_EXTERNAL_SOURCES ${name}
       DEPENDS
         ${SWIFTEXE_SINGLE_DEPENDS}
-        ${SWIFTEXE_SINGLE_LINK_FAT_LIBRARIES_TARGETS}
       MODULE_NAME ${name}
       SDK ${SWIFTEXE_SINGLE_SDK}
       ARCHITECTURE ${SWIFTEXE_SINGLE_ARCHITECTURE}
@@ -2209,8 +2189,7 @@ function(_add_swift_executable_single name)
       DEPENDS
         ${dependency_target}
         ${LLVM_COMMON_DEPENDS}
-        ${SWIFTEXE_SINGLE_DEPENDS}
-        ${SWIFTEXE_SINGLE_LINK_FAT_LIBRARIES_TARGETS})
+        ${SWIFTEXE_SINGLE_DEPENDS})
   llvm_update_compile_flags("${name}")
 
   # Convert variables to space-separated strings.
@@ -2230,11 +2209,10 @@ function(_add_swift_executable_single name)
       BINARY_DIR ${SWIFT_RUNTIME_OUTPUT_INTDIR}
       LIBRARY_DIR ${SWIFT_LIBRARY_OUTPUT_INTDIR})
 
-  target_link_libraries("${name}" PRIVATE ${SWIFTEXE_SINGLE_LINK_LIBRARIES} ${SWIFTEXE_SINGLE_LINK_FAT_LIBRARIES})
+  target_link_libraries("${name}" PRIVATE ${SWIFTEXE_SINGLE_LINK_LIBRARIES})
   swift_common_llvm_config("${name}" ${SWIFTEXE_SINGLE_LLVM_COMPONENT_DEPENDS})
 
-  set_target_properties(${name}
-      PROPERTIES FOLDER "Swift executables")
+  set_target_properties(${name} PROPERTIES FOLDER "Swift executables")
 endfunction()
 
 macro(add_swift_tool_subdirectory name)

stdlib/cmake/modules/AddSwiftStdlib.cmake

@@ -5,16 +5,12 @@ include(AddSwift)
 # with the variant SDK and ARCH.
 #
 # See add_swift_executable for detailed documentation.
-#
-# Additional parameters:
-#   [LINK_FAT_LIBRARIES lipo_target1 ...]
-#     Fat libraries to link with.
 function(add_swift_target_executable name)
   # Parse the arguments we were given.
   cmake_parse_arguments(SWIFTEXE_TARGET
     "EXCLUDE_FROM_ALL;;BUILD_WITH_STDLIB"
     ""
-    "DEPENDS;LLVM_COMPONENT_DEPENDS;LINK_FAT_LIBRARIES"
+    "DEPENDS;LLVM_COMPONENT_DEPENDS;LINK_LIBRARIES"
     ${ARGN})
 
   set(SWIFTEXE_TARGET_SOURCES ${SWIFTEXE_TARGET_UNPARSED_ARGUMENTS})
@@ -24,12 +20,12 @@ function(add_swift_target_executable name)
       SWIFTEXE_TARGET_EXCLUDE_FROM_ALL_FLAG)
 
   # All Swift executables depend on the standard library.
-  list(APPEND SWIFTEXE_TARGET_LINK_FAT_LIBRARIES swiftCore)
+  list(APPEND SWIFTEXE_TARGET_LINK_LIBRARIES swiftCore)
   # All Swift executables depend on the swiftSwiftOnoneSupport library.
   list(APPEND SWIFTEXE_TARGET_DEPENDS swiftSwiftOnoneSupport)
 
   if(NOT "${SWIFT_BUILD_STDLIB}")
-    list(REMOVE_ITEM SWIFTEXE_TARGET_LINK_FAT_LIBRARIES
+    list(REMOVE_ITEM SWIFTEXE_TARGET_LINK_LIBRARIES
         swiftCore)
   endif()
 
@@ -63,7 +59,7 @@ function(add_swift_target_executable name)
           LLVM_COMPONENT_DEPENDS ${SWIFTEXE_TARGET_LLVM_COMPONENT_DEPENDS}
           SDK "${sdk}"
           ARCHITECTURE "${arch}"
-          LINK_FAT_LIBRARIES ${SWIFTEXE_TARGET_LINK_FAT_LIBRARIES}
+          LINK_LIBRARIES ${SWIFTEXE_TARGET_LINK_LIBRARIES}
           ${SWIFTEXE_TARGET_EXCLUDE_FROM_ALL_FLAG_CURRENT})
 
       if(${sdk} IN_LIST SWIFT_APPLE_PLATFORMS)

stdlib/tools/swift-reflection-test/CMakeLists.txt

@@ -1,7 +1,7 @@
 add_swift_target_executable(swift-reflection-test BUILD_WITH_STDLIB
   swift-reflection-test.c
   overrides.c
-  LINK_FAT_LIBRARIES
+  LINK_LIBRARIES
     swiftRemoteMirror
     swiftReflection)
 # NOTE(compnerd) since _WINDLL has no impact on non-Windows targets,