[CMake] Don't pass -embed-bitcode to module generation commands.

These are the commands Pete added in 5834df3, doing slightly more work
by compiling Swift sources twice in order to start building downstream
libraries sooner.

Really, we should diagnose when -embed-bitcode is passed here, instead
of generating nonsense commands and then falling over. I filed
https://bugs.swift.org/browse/SR-3352 for that.

rdar://problem/29537164

Author: jrose-apple

cmake/modules/AddSwift.cmake

@@ -599,11 +599,12 @@ function(_add_swift_library_single target name)
       "${SWIFT_SDK_${SWIFTLIB_SINGLE_SDK}_LIB_SUBDIR}/${SWIFTLIB_SINGLE_ARCHITECTURE}")
 
   # Include LLVM Bitcode slices for iOS, Watch OS, and Apple TV OS device libraries.
-  if(SWIFT_EMBED_BITCODE_SECTION AND NOT SWIFTLIB_DONT_EMBED_BITCODE)
+  set(embed_bitcode_arg)
+  if(SWIFT_EMBED_BITCODE_SECTION AND NOT SWIFTLIB_SINGLE_DONT_EMBED_BITCODE)
     if("${SWIFTLIB_SINGLE_SDK}" STREQUAL "IOS" OR "${SWIFTLIB_SINGLE_SDK}" STREQUAL "TVOS" OR "${SWIFTLIB_SINGLE_SDK}" STREQUAL "WATCHOS")
       list(APPEND SWIFTLIB_SINGLE_C_COMPILE_FLAGS "-fembed-bitcode")
-      list(APPEND SWIFTLIB_SINGLE_SWIFT_COMPILE_FLAGS "-embed-bitcode")
       list(APPEND SWIFTLIB_SINGLE_LINK_FLAGS "-Xlinker" "-bitcode_bundle" "-Xlinker" "-bitcode_hide_symbols" "-Xlinker" "-lto_library" "-Xlinker" "${LLVM_LIBRARY_DIR}/libLTO.dylib")
+      set(embed_bitcode_arg EMBED_BITCODE)
     endif()
   endif()
 
@@ -722,6 +723,7 @@ function(_add_swift_library_single target name)
       ${SWIFTLIB_SINGLE_IS_STDLIB_keyword}
       ${SWIFTLIB_SINGLE_IS_STDLIB_CORE_keyword}
       ${SWIFTLIB_SINGLE_IS_SDK_OVERLAY_keyword}
+      ${embed_bitcode_arg}
       INSTALL_IN_COMPONENT "${SWIFTLIB_INSTALL_IN_COMPONENT}")
   add_swift_source_group("${SWIFTLIB_SINGLE_EXTERNAL_SOURCES}")
 

cmake/modules/SwiftSource.cmake

@@ -10,7 +10,7 @@ function(handle_swift_sources
     dependency_module_target_out_var_name
     sourcesvar externalvar name)
   cmake_parse_arguments(SWIFTSOURCES
-      "IS_MAIN;IS_STDLIB;IS_STDLIB_CORE;IS_SDK_OVERLAY"
+      "IS_MAIN;IS_STDLIB;IS_STDLIB_CORE;IS_SDK_OVERLAY;EMBED_BITCODE"
       "SDK;ARCHITECTURE;INSTALL_IN_COMPONENT"
       "DEPENDS;API_NOTES;COMPILE_FLAGS;MODULE_NAME"
       ${ARGN})
@@ -20,6 +20,8 @@ function(handle_swift_sources
                  IS_STDLIB_CORE_arg)
   translate_flag(${SWIFTSOURCES_IS_SDK_OVERLAY} "IS_SDK_OVERLAY"
                  IS_SDK_OVERLAY_arg)
+  translate_flag(${SWIFTSOURCES_EMBED_BITCODE} "EMBED_BITCODE"
+                 EMBED_BITCODE_arg)
 
   if(SWIFTSOURCES_IS_MAIN)
     set(SWIFTSOURCES_INSTALL_IN_COMPONENT never_install)
@@ -94,6 +96,7 @@ function(handle_swift_sources
         ${IS_STDLIB_arg}
         ${IS_STDLIB_CORE_arg}
         ${IS_SDK_OVERLAY_arg}
+        ${EMBED_BITCODE_arg}
         ${STATIC_arg}
         INSTALL_IN_COMPONENT "${SWIFTSOURCES_INSTALL_IN_COMPONENT}")
     set("${dependency_target_out_var_name}" "${dependency_target}" PARENT_SCOPE)
@@ -138,11 +141,12 @@ endfunction()
 #     [MODULE_NAME]                     # The module name.
 #     [IS_STDLIB]                       # Install produced files.
 #     [EMIT_SIB]                        # Emit the file as a sib file instead of a .o
+#     [EMBED_BITCODE]                   # Embed LLVM bitcode into the .o files
 #     )
 function(_compile_swift_files
          dependency_target_out_var_name dependency_module_target_out_var_name)
   cmake_parse_arguments(SWIFTFILE
-    "IS_MAIN;IS_STDLIB;IS_STDLIB_CORE;IS_SDK_OVERLAY;EMIT_SIB"
+    "IS_MAIN;IS_STDLIB;IS_STDLIB_CORE;IS_SDK_OVERLAY;EMIT_SIB;EMBED_BITCODE"
     "OUTPUT;MODULE_NAME;INSTALL_IN_COMPONENT"
     "SOURCES;FLAGS;DEPENDS;SDK;ARCHITECTURE;API_NOTES;OPT_FLAGS;MODULE_DIR"
     ${ARGN})
@@ -362,6 +366,11 @@ function(_compile_swift_files
     set(output_option "-o" ${first_output})
   endif()
 
+  set(embed_bitcode_option)
+  if (SWIFTFILE_EMBED_BITCODE)
+    set(embed_bitcode_option "-embed-bitcode")
+  endif()
+
   set(main_command "-c")
   if (SWIFTFILE_EMIT_SIB)
     # Change the command to emit-sib if we are asked to emit sib
@@ -429,7 +438,7 @@ function(_compile_swift_files
       COMMAND
         "${line_directive_tool}" "${source_files}" --
         "${swift_compiler_tool}" "${main_command}" ${swift_flags}
-        ${output_option} "${source_files}"
+        ${output_option} ${embed_bitcode_option} "${source_files}"
       ${command_touch_standard_outputs}
       OUTPUT ${standard_outputs}
       DEPENDS