diff --git a/CMakeLists.txt b/CMakeLists.txt
index 342f60855e32a..f8e678b9c297b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -799,6 +799,7 @@ include(SwiftConfigureSDK)
 include(SwiftComponents)
 include(SwiftList)
 include(AddPureSwift)
+include(SetRPATH)
 
 # Configure swift include, install, build components.
 swift_configure_components()
@@ -957,6 +958,12 @@ if(SWIFT_PATH_TO_EARLYSWIFTSYNTAX_BUILD_DIR)
   else()
     set(SWIFT_SWIFT_PARSER TRUE)
     include(${SWIFT_PATH_TO_EARLYSWIFTSYNTAX_TARGETS})
+
+    if(SWIFT_HOST_VARIANT_SDK MATCHES "LINUX|ANDROID|OPENBSD|FREEBSD" AND NOT BOOTSTRAPPING_MODE STREQUAL "HOSTTOOLS")
+      # Only "HOSTTOOLS" is supported in Linux when Swift parser integration is enabled.
+      message(WARNING "Force setting BOOTSTRAPPING=HOSTTOOLS because Swift parser integration is enabled")
+      set(BOOTSTRAPPING_MODE "HOSTTOOLS")
+    endif()
   endif()
 endif()
 
diff --git a/SwiftCompilerSources/CMakeLists.txt b/SwiftCompilerSources/CMakeLists.txt
index 89a78c6486078..51b575aec4b1c 100644
--- a/SwiftCompilerSources/CMakeLists.txt
+++ b/SwiftCompilerSources/CMakeLists.txt
@@ -231,7 +231,7 @@ else()
   #
   # step 1: generate a dummy source file, which just includes all headers
   # defined in include/swift/module.modulemap
-  file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/HeaderDependencies.cpp"
+  file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/HeaderDependencies.cpp.tmp"
        "
 #include \"Basic/BridgedSwiftObject.h\"
 #include \"Basic/BasicBridging.h\"
@@ -247,6 +247,12 @@ else()
 
 #include \"Parse/RegexParserBridging.h\"
 ")
+  add_custom_command(
+    OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/HeaderDependencies.cpp"
+    COMMAND ${CMAKE_COMMAND} -E copy_if_different
+      "${CMAKE_CURRENT_BINARY_DIR}/HeaderDependencies.cpp.tmp"
+      "${CMAKE_CURRENT_BINARY_DIR}/HeaderDependencies.cpp"
+  )
 
   # step 2: build a library containing that source file. This library depends on all the included header files.
   #         The swift modules can now depend on that target.
diff --git a/cmake/modules/AddPureSwift.cmake b/cmake/modules/AddPureSwift.cmake
index 80a2b32ca8a0c..17f5792339941 100644
--- a/cmake/modules/AddPureSwift.cmake
+++ b/cmake/modules/AddPureSwift.cmake
@@ -65,6 +65,25 @@ function(_add_host_swift_compile_options name)
   _add_host_variant_swift_sanitizer_flags(${name})
 endfunction()
 
+function(_set_pure_swift_link_flags name relpath_to_lib_dir)
+  if(SWIFT_HOST_VARIANT_SDK MATCHES "LINUX|ANDROID|OPENBSD|FREEBSD")
+    # Don't add builder's stdlib RPATH automatically.
+    target_compile_options(${name} PRIVATE
+      $<$<COMPILE_LANGUAGE:Swift>:-no-toolchain-stdlib-rpath>
+    )
+
+    set_property(TARGET ${name}
+      APPEND PROPERTY INSTALL_RPATH
+        # At runtime, use swiftCore in the current just-built toolchain.
+        # NOTE: This relies on the ABI being the same as the builder.
+        "$ORIGIN/${relpath_to_lib_dir}/swift/${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_LIB_SUBDIR}"
+    )
+    # NOTE: At this point we don't have any pure swift executables/shared
+    # libraries required for building runtime/stdlib. So we don't need to add
+    # RPATH to the builder's runtime.
+  endif()
+endfunction()
+
 # Add a new "pure" Swift host library.
 #
 # "Pure" Swift host libraries can only contain Swift code, and will be built
@@ -266,10 +285,17 @@ function(add_pure_swift_host_tool name)
   # Create the library.
   add_executable(${name} ${APSHT_SOURCES})
   _add_host_swift_compile_options(${name})
-
-  set_property(TARGET ${name}
-    APPEND PROPERTY INSTALL_RPATH
-      "@executable_path/../lib/swift/host")
+  _set_pure_swift_link_flags(${name} "../lib")
+
+  if(${SWIFT_HOST_VARIANT_SDK} IN_LIST SWIFT_DARWIN_PLATFORMS)
+    set_property(TARGET ${name}
+      APPEND PROPERTY INSTALL_RPATH
+        "@executable_path/../lib/swift/host")
+  elseif(SWIFT_HOST_VARIANT_SDK MATCHES "LINUX|ANDROID|OPENBSD|FREEBSD")
+    set_property(TARGET ${name}
+      APPEND PROPERTY INSTALL_RPATH
+        "$ORIGIN/../lib/swift/host")
+  endif()
 
   set_property(TARGET ${name}
     PROPERTY BUILD_WITH_INSTALL_RPATH YES)
diff --git a/cmake/modules/AddSwift.cmake b/cmake/modules/AddSwift.cmake
index 5b8365e930ce8..76702543d25dd 100644
--- a/cmake/modules/AddSwift.cmake
+++ b/cmake/modules/AddSwift.cmake
@@ -545,11 +545,11 @@ function(_add_swift_runtime_link_flags target relpath_to_lib_dir bootstrapping)
       target_link_libraries(${target} PRIVATE "swiftCore")
 
       target_link_directories(${target} PRIVATE ${host_lib_dir})
-      if(ASRLF_BOOTSTRAPPING_MODE STREQUAL "HOSTTOOLS")
-        set(swift_runtime_rpath "${host_lib_dir}")
-      else()
-        set(swift_runtime_rpath "$ORIGIN/${relpath_to_lib_dir}/swift/${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_LIB_SUBDIR}")
-      endif()
+
+      # At runtime, use swiftCore in the current toolchain.
+      # For building stdlib, LD_LIBRARY_PATH will be set to builder's stdlib
+      # FIXME: This assumes the ABI hasn't changed since the builder.
+      set(swift_runtime_rpath "$ORIGIN/${relpath_to_lib_dir}/swift/${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_LIB_SUBDIR}")
 
     elseif(ASRLF_BOOTSTRAPPING_MODE STREQUAL "BOOTSTRAPPING")
       # At build time link against the built swift libraries from the
@@ -573,10 +573,7 @@ function(_add_swift_runtime_link_flags target relpath_to_lib_dir bootstrapping)
   endif()
 
   if(SWIFT_SWIFT_PARSER)
-    # Make sure we can find the early SwiftSyntax libraries.
-    target_link_directories(${target} PRIVATE "${SWIFT_PATH_TO_EARLYSWIFTSYNTAX_BUILD_DIR}/lib/swift/host")
-
-    # For the "end step" of bootstrapping configurations on Darwin, need to be
+    # For the "end step" of bootstrapping configurations, we need to be
     # able to fall back to the SDK directory for libswiftCore et al.
     if (BOOTSTRAPPING_MODE MATCHES "BOOTSTRAPPING.*")
       if (NOT "${bootstrapping}" STREQUAL "1")
@@ -590,6 +587,13 @@ function(_add_swift_runtime_link_flags target relpath_to_lib_dir bootstrapping)
           get_filename_component(TOOLCHAIN_BIN_DIR ${SWIFT_EXEC_FOR_SWIFT_MODULES} DIRECTORY)
           get_filename_component(TOOLCHAIN_LIB_DIR "${TOOLCHAIN_BIN_DIR}/../lib/swift/${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_LIB_SUBDIR}" ABSOLUTE)
           target_link_directories(${target} PUBLIC ${TOOLCHAIN_LIB_DIR})
+        else()
+          get_filename_component(swift_bin_dir ${SWIFT_EXEC_FOR_SWIFT_MODULES} DIRECTORY)
+          get_filename_component(swift_dir ${swift_bin_dir} DIRECTORY)
+          set(host_lib_dir "${swift_dir}/lib/swift/${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_LIB_SUBDIR}")
+          target_link_directories(${target} PRIVATE ${host_lib_dir})
+
+          set(swift_runtime_rpath "${host_lib_dir}")
         endif()
       endif()
     endif()
@@ -822,8 +826,43 @@ macro(add_swift_lib_subdirectory name)
   add_llvm_subdirectory(SWIFT LIB ${name})
 endmacro()
 
+# Add a new Swift host executable.
+#
+# Usage:
+#   add_swift_host_tool(name
+#     [HAS_SWIFT_MODULES | DOES_NOT_USE_SWIFT]
+#     [THINLTO_LD64_ADD_FLTO_CODEGEN_ONLY]
+#
+#     [BOOTSTRAPPING 0|1]
+#     [SWIFT_COMPONENT component]
+#     [LLVM_LINK_COMPONENTS comp1 ...]
+#     source1 [source2 source3 ...])
+#
+# name
+#   Name of the executable (e.g., swift-frontend).
+#
+# HAS_SWIFT_MODULES
+#   Whether to link with SwiftCompilerSources library
+#
+# DOES_NOT_USE_SWIFT
+#   Do not link with swift runtime
+#
+# THINLTO_LD64_ADD_FLTO_CODEGEN_ONLY
+#   Opt-out of LLVM IR optimizations when linking ThinLTO with ld64
+#
+# BOOTSTRAPPING
+#   Bootstrapping stage.
+#
+# SWIFT_COMPONENT
+#   Installation component where this tool belongs to.
+#
+# LLVM_LINK_COMPONENTS
+#   LLVM components this library depends on.
+#
+# source1 ...
+#   Sources to add into this executable.
 function(add_swift_host_tool executable)
-  set(options HAS_SWIFT_MODULES THINLTO_LD64_ADD_FLTO_CODEGEN_ONLY)
+  set(options HAS_SWIFT_MODULES DOES_NOT_USE_SWIFT THINLTO_LD64_ADD_FLTO_CODEGEN_ONLY)
   set(single_parameter_options SWIFT_COMPONENT BOOTSTRAPPING)
   set(multiple_parameter_options LLVM_LINK_COMPONENTS)
 
@@ -879,12 +918,12 @@ function(add_swift_host_tool executable)
   endif()
 
   # Once the new Swift parser is linked in, every host tool has Swift modules.
-  if (SWIFT_SWIFT_PARSER)
+  if (SWIFT_SWIFT_PARSER AND NOT ASHT_DOES_NOT_USE_SWIFT)
     set(ASHT_HAS_SWIFT_MODULES ON)
   endif()
 
   if (ASHT_HAS_SWIFT_MODULES)
-      _add_swift_runtime_link_flags(${executable} "../lib" "${ASHT_BOOTSTRAPPING}")
+    _add_swift_runtime_link_flags(${executable} "../lib" "${ASHT_BOOTSTRAPPING}")
   endif()
 
   llvm_update_compile_flags(${executable})
@@ -926,10 +965,17 @@ function(add_swift_host_tool executable)
       endif()
     endif()
 
-    set_property(
-      TARGET ${executable}
-      APPEND PROPERTY INSTALL_RPATH
-        "@executable_path/../${extra_relative_rpath}lib/swift/host")
+    if(${SWIFT_HOST_VARIANT_SDK} IN_LIST SWIFT_DARWIN_PLATFORMS)
+      set_property(
+        TARGET ${executable}
+        APPEND PROPERTY INSTALL_RPATH
+          "@executable_path/../${extra_relative_rpath}lib/swift/host")
+    else()
+      set_property(
+        TARGET ${executable}
+        APPEND PROPERTY INSTALL_RPATH
+          "$ORIGIN/../${extra_relative_rpath}lib/swift/host")
+    endif()
   endif()
 
   if(ASHT_THINLTO_LD64_ADD_FLTO_CODEGEN_ONLY)
@@ -950,7 +996,8 @@ function(add_swift_host_tool executable)
     swift_install_in_component(TARGETS ${executable}
                                RUNTIME
                                  DESTINATION bin
-                                 COMPONENT ${ASHT_SWIFT_COMPONENT})
+                                 COMPONENT ${ASHT_SWIFT_COMPONENT}
+    )
 
     swift_is_installing_component(${ASHT_SWIFT_COMPONENT} is_installing)
   endif()
diff --git a/cmake/modules/AddSwiftUnittests.cmake b/cmake/modules/AddSwiftUnittests.cmake
index a4573981c225c..45acb9bf10698 100644
--- a/cmake/modules/AddSwiftUnittests.cmake
+++ b/cmake/modules/AddSwiftUnittests.cmake
@@ -5,10 +5,32 @@ add_custom_target(SwiftUnitTests)
 
 set_target_properties(SwiftUnitTests PROPERTIES FOLDER "Tests")
 
+# Add a new Swift unit test executable.
+#
+# Usage:
+#   add_swift_unittest(name
+#     [IS_TARGET_TEST]
+#     source1 [source2 source3 ...])
+#
+# name
+#   Name of the test (e.g., SwiftASTTest).
+#
+# IS_TARGET_TEST
+#   Indicates this is a test for target libraries. Not host library.
+#   This avoids linking with toolchains stdlib.
+#
+# source1 ...
+#   Sources to add into this executable.
 function(add_swift_unittest test_dirname)
+  cmake_parse_arguments(ASU
+                        "IS_TARGET_TEST"
+                        ""
+                        ""
+                        ${ARGN})
+
   # *NOTE* Even though "add_unittest" does not have llvm in its name, it is a
   # function defined by AddLLVM.cmake.
-  add_unittest(SwiftUnitTests ${test_dirname} ${ARGN})
+  add_unittest(SwiftUnitTests ${test_dirname} ${ASU_UNPARSED_ARGUMENTS})
 
   set_target_properties(${test_dirname} PROPERTIES LINKER_LANGUAGE CXX)
 
@@ -89,7 +111,8 @@ function(add_swift_unittest test_dirname)
     endif()
   endif()
 
-  if (SWIFT_SWIFT_PARSER)
+  if (SWIFT_SWIFT_PARSER AND NOT ASU_IS_TARGET_TEST)
+    # Link to stdlib the compiler uses.
     _add_swift_runtime_link_flags(${test_dirname} "../../lib" "")
     set_property(TARGET ${test_dirname} PROPERTY BUILD_WITH_INSTALL_RPATH OFF)
   endif()
diff --git a/cmake/modules/SetRPATH.cmake b/cmake/modules/SetRPATH.cmake
new file mode 100644
index 0000000000000..76b8b4644e59a
--- /dev/null
+++ b/cmake/modules/SetRPATH.cmake
@@ -0,0 +1,24 @@
+set(SWIFT_SET_RPATH_SCRIPT_FILE "${CMAKE_CURRENT_LIST_FILE}")
+
+function(swift_get_set_rpath_script_file out_var)
+  set(${out_var} "${SWIFT_SET_RPATH_SCRIPT_FILE}" PARENT_SCOPE)
+endfunction()
+
+# Actual RPATH_CHANGE operation to the file.
+function(_swift_set_rpath_impl file new_rpath)
+  # FIXME: Handle non-ELF files. We can't use RPATH_SET because it's only available CMake 3.21.0
+  execute_process(
+    COMMAND readelf -Wd "${file}"
+    COMMAND grep -Po "R(UN)?PATH.*\\[\\K[^\\]]*"
+    OUTPUT_VARIABLE current_rpath
+  )
+  string(STRIP "${current_rpath}" current_rpath)
+
+  # NOTE: RPATH_CHANGE is not documented, and works only for ELF and XCOFF.
+  file(RPATH_CHANGE FILE "${file}" OLD_RPATH "${current_rpath}" NEW_RPATH "${new_rpath}")
+endfunction()
+
+# For 'cmake -P <scirpt>'.
+if (SWIFT_SET_RPATH_FILE AND SWIFT_SET_RPATH_NEW_RPATH)
+  _swift_set_rpath_impl("${SWIFT_SET_RPATH_FILE}" "${SWIFT_SET_RPATH_NEW_RPATH}")
+endif()
diff --git a/cmake/modules/SwiftImplicitImport.cmake b/cmake/modules/SwiftImplicitImport.cmake
index 50c5e5415ff81..3c79357f01883 100644
--- a/cmake/modules/SwiftImplicitImport.cmake
+++ b/cmake/modules/SwiftImplicitImport.cmake
@@ -6,7 +6,7 @@ function(swift_supports_implicit_module module_name out_var)
       "${CMAKE_Swift_COMPILER}"
       -Xfrontend -disable-implicit-${module_name}-module-import
       -Xfrontend -parse-stdlib
-      -c - -o /dev/null
+      -parse -
     INPUT_FILE
       "${CMAKE_BINARY_DIR}/tmp/empty-check-${module_name}.swift"
     OUTPUT_QUIET ERROR_QUIET
diff --git a/cmake/modules/SwiftUtils.cmake b/cmake/modules/SwiftUtils.cmake
index 9d6b2ce73af94..7e682f7f6471e 100644
--- a/cmake/modules/SwiftUtils.cmake
+++ b/cmake/modules/SwiftUtils.cmake
@@ -107,6 +107,16 @@ function(get_bootstrapping_swift_lib_dir bs_lib_dir bootstrapping)
     elseif("${bootstrapping}" STREQUAL "")
       get_bootstrapping_path(bs_lib_dir ${lib_dir} "1")
     endif()
+  elseif(BOOTSTRAPPING_MODE STREQUAL "HOSTTOOLS")
+    if(SWIFT_HOST_VARIANT_SDK MATCHES "LINUX|ANDROID|OPENBSD|FREEBSD")
+      # Compiler's INSTALL_RPATH is set to libs in the build directory
+      # For building stdlib, use stdlib in the builder's resource directory
+      # because the runtime may not be built yet.
+      # FIXME: This assumes the ABI hasn't changed since the builder.
+      get_filename_component(swift_bin_dir ${CMAKE_Swift_COMPILER} DIRECTORY)
+      get_filename_component(swift_dir ${swift_bin_dir} DIRECTORY)
+      set(bs_lib_dir "${swift_dir}/lib/swift/${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_LIB_SUBDIR}")
+    endif()
   endif()
   set(bs_lib_dir ${bs_lib_dir} PARENT_SCOPE)
 endfunction()
diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt
index 55e8d7dc73ae2..846d165345b56 100644
--- a/lib/CMakeLists.txt
+++ b/lib/CMakeLists.txt
@@ -36,7 +36,7 @@ if (SWIFT_SWIFT_PARSER)
   list(TRANSFORM SWIFT_SYNTAX_MODULES PREPEND "SwiftSyntax::"
        OUTPUT_VARIABLE SWIFT_SYNTAX_TARGETS)
 
-  set(SWIFT_SYNTAX_LIBRARIES_SOURCE_DIR
+  set(SWIFT_SYNTAX_LIBRARIES_BUILD_DIR
       "${SWIFT_PATH_TO_EARLYSWIFTSYNTAX_BUILD_DIR}/lib/swift/host")
   set(SWIFT_HOST_LIBRARIES_DEST_DIR
       "${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/swift/host")
@@ -56,10 +56,22 @@ if (SWIFT_SWIFT_PARSER)
   # Copy over all of the shared libraries from earlyswiftsyntax so they can
   # be found via RPATH.
   foreach (sharedlib ${SWIFT_SYNTAX_SHARED_LIBRARIES})
+    set(add_origin_rpath)
+    if(SWIFT_HOST_VARIANT_SDK MATCHES "LINUX|ANDROID|OPENBSD|FREEBSD")
+      # At runtime, use swiftCore in the current toolchain.
+      swift_get_set_rpath_script_file(setrpath_command)
+      set(add_origin_rpath COMMAND ${CMAKE_COMMAND}
+        "-DSWIFT_SET_RPATH_FILE=${SWIFT_HOST_LIBRARIES_DEST_DIR}/${sharedlib}"
+        "-DSWIFT_SET_RPATH_NEW_RPATH='$$ORIGIN:$$ORIGIN/../${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_LIB_SUBDIR}'"
+        -P "${setrpath_command}"
+      )
+    endif()
+
     add_custom_command(
       OUTPUT "${SWIFT_HOST_LIBRARIES_DEST_DIR}/${sharedlib}"
-      DEPENDS "${SWIFT_SYNTAX_LIBRARIES_SOURCE_DIR}/${sharedlib}"
-      COMMAND ${CMAKE_COMMAND} -E copy_if_different ${SWIFT_SYNTAX_LIBRARIES_SOURCE_DIR}/${sharedlib} ${SWIFT_HOST_LIBRARIES_DEST_DIR}/${sharedlib}
+      DEPENDS "${SWIFT_SYNTAX_LIBRARIES_BUILD_DIR}/${sharedlib}"
+      COMMAND ${CMAKE_COMMAND} -E copy_if_different ${SWIFT_SYNTAX_LIBRARIES_BUILD_DIR}/${sharedlib} ${SWIFT_HOST_LIBRARIES_DEST_DIR}/${sharedlib}
+      ${add_origin_rpath}
     )
 
     add_custom_target(copy_swiftSyntaxLibrary_${sharedlib}
@@ -67,6 +79,12 @@ if (SWIFT_SWIFT_PARSER)
       COMMENT "Copying ${sharedlib}"
     )
 
+    swift_install_in_component(
+      PROGRAMS "${SWIFT_HOST_LIBRARIES_DEST_DIR}/${sharedlib}"
+      DESTINATION "lib${LLVM_LIBDIR_SUFFIX}/swift/host"
+      COMPONENT compiler
+    )
+
     add_dependencies(swiftSyntaxLibraries copy_swiftSyntaxLibrary_${sharedlib})
   endforeach()
 
@@ -79,7 +97,7 @@ if (SWIFT_SWIFT_PARSER)
   foreach(module_dir ${SWIFT_SYNTAX_MODULE_DIRS})
     # Find all of the source module files.
     file(GLOB module_files
-         "${SWIFT_SYNTAX_LIBRARIES_SOURCE_DIR}/${module_dir}/*.swiftinterface")
+      "${SWIFT_SYNTAX_LIBRARIES_BUILD_DIR}/${module_dir}/*.swiftinterface")
 
     # Determine the destination module files.
     set(dest_module_files)
@@ -101,6 +119,12 @@ if (SWIFT_SWIFT_PARSER)
       COMMENT "Copying ${module_dir}"
     )
 
+    swift_install_in_component(
+      FILES ${dest_module_files}
+      DESTINATION "lib${LLVM_LIBDIR_SUFFIX}/swift/host/${module_dir}"
+      COMPONENT compiler
+    )
+
     add_dependencies(swiftSyntaxLibraries copy_swiftSyntaxModule_${module_dir})
   endforeach()
 
diff --git a/lib/Macros/CMakeLists.txt b/lib/Macros/CMakeLists.txt
index ed98b3d9f5789..3598a4e917557 100644
--- a/lib/Macros/CMakeLists.txt
+++ b/lib/Macros/CMakeLists.txt
@@ -37,6 +37,19 @@ function(add_swift_macro_library name)
     return()
   endif()
 
+  # Add rpath to 'lib/{platform}'
+  file(RELATIVE_PATH relpath_to_lib
+    "${SWIFT_HOST_PLUGINS_DEST_DIR}"
+    "${CMAKE_LIBRARY_OUTPUT_DIRECTORY}"
+  )
+  _set_pure_swift_link_flags(${name} "${relpath_to_lib}")
+
+  # Add rpath to 'lib/host'
+  if(SWIFT_HOST_VARIANT_SDK MATCHES "LINUX|ANDROID|OPENBSD|FREEBSD")
+    set_property(TARGET ${name}
+      APPEND PROPERTY INSTALL_RPATH "$ORIGIN/..")
+  endif()
+
   # Install into the plugin directory.
   set_target_properties(${name}
     PROPERTIES
@@ -44,12 +57,14 @@ function(add_swift_macro_library name)
       LIBRARY_OUTPUT_DIRECTORY "${SWIFT_HOST_PLUGINS_DEST_DIR}"
   )
 
+  set(destination_dir "lib${LLVM_LIBDIR_SUFFIX}/swift/host/plugins")
+
   swift_install_in_component(TARGETS ${name}
     LIBRARY
-      DESTINATION "lib${LLVM_LIBDIR_SUFFIX}/swift/host/plugins"
+      DESTINATION "${destination_dir}"
       COMPONENT compiler
     ARCHIVE
-      DESTINATION "lib${LLVM_LIBDIR_SUFFIX}/swift/host/plugins"
+      DESTINATION "${destination_dir}"
       COMPONENT compiler)
 
   # Export this macro plugin target.
diff --git a/lib/SILOptimizer/Utils/BasicBlockOptUtils.cpp b/lib/SILOptimizer/Utils/BasicBlockOptUtils.cpp
index 5cf2c81fb6d6b..1db6a8879cb1d 100644
--- a/lib/SILOptimizer/Utils/BasicBlockOptUtils.cpp
+++ b/lib/SILOptimizer/Utils/BasicBlockOptUtils.cpp
@@ -367,3 +367,12 @@ StaticInitCloner::clone(SingleValueInstruction *initVal) {
   }
   return cast<SingleValueInstruction>(getMappedValue(initVal));
 }
+
+// START: Workaround for C++ interop
+#include <tuple>
+template std::pair<SILInstruction *, SILInstruction *> std::make_pair<>(SILInstruction *&&, SILInstruction *&&);
+template std::pair<SILValue, SILInstruction *> std::make_pair<>(SILValue &&, SILInstruction *&&);
+template std::pair<SILType, SILType> std::make_pair<>(SILType &&, SILType &&);
+template llvm::DomTreeNodeBase<SILBasicBlock> *&std::get<0>(std::tuple<llvm::DomTreeNodeBase<SILBasicBlock> *, std::default_delete<llvm::DomTreeNodeBase<SILBasicBlock>>> &);
+template std::default_delete<llvm::DomTreeNodeBase<SILBasicBlock>> &std::get<1>(std::tuple<llvm::DomTreeNodeBase<SILBasicBlock> *, std::default_delete<llvm::DomTreeNodeBase<SILBasicBlock>>> &);
+// END: Workaround for C++ interop
diff --git a/stdlib/cmake/modules/SwiftSource.cmake b/stdlib/cmake/modules/SwiftSource.cmake
index 3ea29705af520..e91471aeffff7 100644
--- a/stdlib/cmake/modules/SwiftSource.cmake
+++ b/stdlib/cmake/modules/SwiftSource.cmake
@@ -799,20 +799,24 @@ function(_compile_swift_files
     set(swift_compiler_tool "${SWIFT_SOURCE_DIR}/utils/check-incremental" "${swift_compiler_tool}")
   endif()
 
-  if(SWIFTFILE_IS_STDLIB)
+  set(custom_env "PYTHONIOENCODING=UTF8")
+  if(SWIFTFILE_IS_STDLIB OR
+     # Linux "hosttools" build require builder's runtime before building the runtime.
+     (BOOTSTRAPPING_MODE STREQUAL "HOSTTOOLS" AND SWIFT_HOST_VARIANT_SDK MATCHES "LINUX|ANDROID|OPENBSD|FREEBSD")
+  )
     get_bootstrapping_swift_lib_dir(bs_lib_dir "${SWIFTFILE_BOOTSTRAPPING}")
     if(bs_lib_dir)
       # When building the stdlib with bootstrapping, the compiler needs
       # to pick up the stdlib from the previous bootstrapping stage, because the
       # stdlib in the current stage is not built yet.
-      if(${SWIFT_HOST_VARIANT_SDK} IN_LIST SWIFT_APPLE_PLATFORMS)
-        set(set_environment_args "${CMAKE_COMMAND}" "-E" "env" "DYLD_LIBRARY_PATH=${bs_lib_dir}")
+      if(SWIFT_HOST_VARIANT_SDK IN_LIST SWIFT_APPLE_PLATFORMS)
+        list(APPEND custom_env "DYLD_LIBRARY_PATH=${bs_lib_dir}")
       elseif(SWIFT_HOST_VARIANT_SDK MATCHES "LINUX|ANDROID|OPENBSD|FREEBSD")
-        set(set_environment_args "${CMAKE_COMMAND}" "-E" "env" "LD_LIBRARY_PATH=${bs_lib_dir}")
+        list(APPEND custom_env "LD_LIBRARY_PATH=${bs_lib_dir}")
       endif()
     endif()
-
   endif()
+  set(set_environment_args "${CMAKE_COMMAND}" "-E" "env" "${custom_env}")
 
   if (SWIFT_REPORT_STATISTICS)
     list(GET dirs_to_create 0 first_obj_dir)
diff --git a/test/Macros/macro_swiftdeps.swift b/test/Macros/macro_swiftdeps.swift
index dd969f3d6e9a9..2b6438e7ffada 100644
--- a/test/Macros/macro_swiftdeps.swift
+++ b/test/Macros/macro_swiftdeps.swift
@@ -7,7 +7,7 @@
 
 // RUN: split-file %s %t/src
 
-//#-- Prepare the macro dylib plugin.
+//#-- Prepare the macro shared library plugin.
 // RUN: %host-build-swift \
 // RUN:   -swift-version 5 \
 // RUN:   -emit-library -o %t/plugin/%target-library-name(MacroDefinition) \
@@ -76,7 +76,7 @@
 // RUN: %FileCheck --check-prefix WITHOUT_PLUGIN %s < %t/with_macro_nonprimary.swiftdeps.processed
 
 // WITH_PLUGIN: externalDepend interface '' 'BUILD_DIR{{.*}}mock-plugin' false
-// WITH_PLUGIN: externalDepend interface '' 'BUILD_DIR{{.*}}libMacroDefinition.dylib' false
+// WITH_PLUGIN: externalDepend interface '' 'BUILD_DIR{{.*}}libMacroDefinition.{{(dylib|so|dll)}}' false
 
 // WITHOUT_PLUGIN-NOT:  MacroDefinition
 // WITHOUT_PLUGIN-NOT:  mock-plugin
diff --git a/test/lit.cfg b/test/lit.cfg
index d74963fc49c0c..76d61f614b7dd 100644
--- a/test/lit.cfg
+++ b/test/lit.cfg
@@ -526,27 +526,31 @@ lit_config.note("Using code completion cache: " + completion_cache_path)
 
 config.swift_host_lib_dir = make_path(config.swift_lib_dir, 'swift', 'host')
 
-if kIsWindows:
-    config.swift_driver = (
-        "%r %s %s %s -libc %s" % (config.swift, mcp_opt,
-                                  config.swift_test_options,
-                                  config.swift_driver_test_options,
-                                  config.swift_stdlib_msvc_runtime))
-    config.swiftc_driver = (
-        "%r -toolchain-stdlib-rpath %s %s %s" % (config.swiftc, mcp_opt,
-                                                 config.swift_test_options,
-                                                 config.swift_driver_test_options))
-else:
+if platform.system() == 'Darwin':
     config.swift_driver = (
         "env SDKROOT=%s %r %s %s %s"
         % (shell_quote(config.host_sdkroot), config.swift, mcp_opt, config.swift_test_options, config.swift_driver_test_options))
     config.swiftc_driver = (
         "env SDKROOT=%s %r -toolchain-stdlib-rpath -Xlinker -rpath -Xlinker /usr/lib/swift %s %s %s"
         % (shell_quote(config.host_sdkroot), config.swiftc, mcp_opt, config.swift_test_options, config.swift_driver_test_options))
-
-config.host_build_swift = (
-    "%s -sdk %s -target %s -I %s -L %s" % (config.swiftc_driver, config.host_sdkroot, config.host_triple, config.swift_host_lib_dir, config.swift_host_lib_dir)
-)
+    config.host_build_swift = (
+        "%s -sdk %s -target %s -I %s -L %s"
+        % (config.swiftc_driver, config.host_sdkroot, config.host_triple, config.swift_host_lib_dir, config.swift_host_lib_dir))
+else:
+    config.swift_driver = (
+        "%r %s %s %s"
+        % (config.swift, mcp_opt, config.swift_test_options, config.swift_driver_test_options))
+    if kIsWindows:
+        config.swift_driver += " -libc " + config.swift_stdlib_msvc_runtime
+    config.swiftc_driver = (
+        "%r -toolchain-stdlib-rpath %s %s %s"
+        % (config.swiftc, mcp_opt, config.swift_test_options, config.swift_driver_test_options))
+    # Parse the host triple.
+    (host_cpu, host_vendor, host_os, host_vers) = re.match('([^-]+)-([^-]+)-([^0-9-]+)(.*)', config.host_triple).groups()
+    toolchain_lib_dir = make_path(config.swift_lib_dir, 'swift', host_os)
+    config.host_build_swift = (
+        "%s -target %s -I %s -L %s -Xlinker -rpath -Xlinker %s"
+        % (config.swiftc_driver, config.host_triple, config.swift_host_lib_dir, config.swift_host_lib_dir, toolchain_lib_dir))
 
 config.substitutions.append( ('%llvm_obj_root', config.llvm_obj_root) )
 config.substitutions.append( ('%swift-lib-dir', config.swift_lib_dir) )
diff --git a/tools/SourceKit/cmake/modules/AddSwiftSourceKit.cmake b/tools/SourceKit/cmake/modules/AddSwiftSourceKit.cmake
index 5c480dcd4a0ba..09f7c437c2f49 100644
--- a/tools/SourceKit/cmake/modules/AddSwiftSourceKit.cmake
+++ b/tools/SourceKit/cmake/modules/AddSwiftSourceKit.cmake
@@ -116,6 +116,11 @@ function(add_sourcekit_swift_runtime_link_flags target path HAS_SWIFT_MODULES)
 
     endif() # HAS_SWIFT_MODULES AND ASKD_BOOTSTRAPPING_MODE
 
+    if(SWIFT_SWIFT_PARSER)
+      # Add rpath to the host Swift libraries.
+      file(RELATIVE_PATH relative_hostlib_path "${path}" "${SWIFTLIB_DIR}/host")
+      list(APPEND RPATH_LIST "@loader_path/${relative_hostlib_path}")
+    endif()
   elseif(SWIFT_HOST_VARIANT_SDK MATCHES "LINUX|ANDROID|OPENBSD" AND HAS_SWIFT_MODULES AND ASKD_BOOTSTRAPPING_MODE)
     set(swiftrt "swiftImageRegistrationObject${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_OBJECT_FORMAT}-${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_LIB_SUBDIR}-${SWIFT_HOST_VARIANT_ARCH}")
     if(${ASKD_BOOTSTRAPPING_MODE} MATCHES "HOSTTOOLS|CROSSCOMPILE")
@@ -129,12 +134,11 @@ function(add_sourcekit_swift_runtime_link_flags target path HAS_SWIFT_MODULES)
       target_link_libraries(${target} PRIVATE "swiftCore")
 
       target_link_directories(${target} PRIVATE ${host_lib_dir})
-      if(ASKD_BOOTSTRAPPING_MODE STREQUAL "HOSTTOOLS")
-        list(APPEND RPATH_LIST "${host_lib_dir}")
-      else()
-        file(RELATIVE_PATH relative_rtlib_path "${path}" "${SWIFTLIB_DIR}/${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_LIB_SUBDIR}")
-        list(APPEND RPATH_LIST "$ORIGIN/${relative_rtlib_path}")
-      endif()
+
+      file(RELATIVE_PATH relative_rtlib_path "${path}" "${SWIFTLIB_DIR}/${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_LIB_SUBDIR}")
+      list(APPEND RPATH_LIST "$ORIGIN/${relative_rtlib_path}")
+      # NOTE: SourceKit components are NOT executed before stdlib is built.
+      # So there's no need to add RUNPATH to builder's runtime libraries.
 
     elseif(ASKD_BOOTSTRAPPING_MODE STREQUAL "BOOTSTRAPPING")
       get_bootstrapping_swift_lib_dir(bs_lib_dir "")
@@ -152,31 +156,33 @@ function(add_sourcekit_swift_runtime_link_flags target path HAS_SWIFT_MODULES)
     else()
       message(FATAL_ERROR "Unknown ASKD_BOOTSTRAPPING_MODE '${ASKD_BOOTSTRAPPING_MODE}'")
     endif()
+
+    if(SWIFT_SWIFT_PARSER)
+      # Add rpath to the host Swift libraries.
+      file(RELATIVE_PATH relative_hostlib_path "${path}" "${SWIFTLIB_DIR}/host")
+      list(APPEND RPATH_LIST "$ORIGIN/${relative_hostlib_path}")
+    endif()
   endif()
-  set(RPATH_LIST ${RPATH_LIST} PARENT_SCOPE)
 
   if(SWIFT_SWIFT_PARSER)
-    # Make sure we can find the early SwiftSyntax libraries.
-    target_link_directories(${target} PRIVATE "${SWIFT_PATH_TO_EARLYSWIFTSYNTAX_BUILD_DIR}/lib/swift/host")
-
     # For the "end step" of bootstrapping configurations on Darwin, need to be
     # able to fall back to the SDK directory for libswiftCore et al.
     if (BOOTSTRAPPING_MODE MATCHES "BOOTSTRAPPING.*")
-      if (NOT "${bootstrapping}" STREQUAL "1")
-        if(${SWIFT_HOST_VARIANT_SDK} IN_LIST SWIFT_DARWIN_PLATFORMS)
-          target_link_directories(${target} PRIVATE "${sdk_dir}")
-
-          # Include the abi stable system stdlib in our rpath.
-          set(swift_runtime_rpath "/usr/lib/swift")
-
-          # Add in the toolchain directory so we can grab compatibility libraries
-          get_filename_component(TOOLCHAIN_BIN_DIR ${SWIFT_EXEC_FOR_SWIFT_MODULES} DIRECTORY)
-          get_filename_component(TOOLCHAIN_LIB_DIR "${TOOLCHAIN_BIN_DIR}/../lib/swift/${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_LIB_SUBDIR}" ABSOLUTE)
-          target_link_directories(${target} PUBLIC ${TOOLCHAIN_LIB_DIR})
-        endif()
+      if(SWIFT_HOST_VARIANT_SDK IN_LIST SWIFT_DARWIN_PLATFORMS)
+        target_link_directories(${target} PRIVATE "${sdk_dir}")
+
+        # Include the abi stable system stdlib in our rpath.
+        set(swift_runtime_rpath "/usr/lib/swift")
+
+        # Add in the toolchain directory so we can grab compatibility libraries
+        get_filename_component(TOOLCHAIN_BIN_DIR ${SWIFT_EXEC_FOR_SWIFT_MODULES} DIRECTORY)
+        get_filename_component(TOOLCHAIN_LIB_DIR "${TOOLCHAIN_BIN_DIR}/../lib/swift/${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_LIB_SUBDIR}" ABSOLUTE)
+        target_link_directories(${target} PUBLIC ${TOOLCHAIN_LIB_DIR})
       endif()
     endif()
   endif()
+
+  set(RPATH_LIST ${RPATH_LIST} PARENT_SCOPE)
 endfunction()
 
 # Add a new SourceKit library.
@@ -287,6 +293,7 @@ macro(add_sourcekit_library name)
     RUNTIME
       DESTINATION "bin"
       COMPONENT "${SOURCEKITLIB_INSTALL_IN_COMPONENT}")
+
   swift_install_in_component(FILES ${SOURCEKITLIB_HEADERS}
                              DESTINATION "include/SourceKit"
                              COMPONENT "${SOURCEKITLIB_INSTALL_IN_COMPONENT}")
@@ -337,16 +344,6 @@ macro(add_sourcekit_executable name)
   add_sourcekit_default_compiler_flags("${name}")
 
   set_target_properties(${name} PROPERTIES LINKER_LANGUAGE CXX)
-
-  if(SWIFT_SWIFT_PARSER)
-    set(SKEXEC_HAS_SWIFT_MODULES TRUE)
-  else()
-    set(SKEXEC_HAS_SWIFT_MODULES FALSE)
-  endif()
-
-  set(RPATH_LIST)
-  add_sourcekit_swift_runtime_link_flags(${name} ${SOURCEKIT_LIBRARY_OUTPUT_INTDIR} ${SKEXEC_HAS_SWIFT_MODULES})
-
 endmacro()
 
 # Add a new SourceKit framework.
diff --git a/tools/libSwiftScan/CMakeLists.txt b/tools/libSwiftScan/CMakeLists.txt
index 5854d77a77e5e..78a6169b224d3 100644
--- a/tools/libSwiftScan/CMakeLists.txt
+++ b/tools/libSwiftScan/CMakeLists.txt
@@ -30,14 +30,36 @@ set_target_properties(libSwiftScan
     PROPERTIES
     OUTPUT_NAME ${SWIFT_SCAN_LIB_NAME})
 
-if(SWIFT_SWIFT_PARSER)
-  # Ensure that we can find the host shared libraries.
-  set_property(
-    TARGET libSwiftScan
-    APPEND PROPERTY INSTALL_RPATH "@loader_path/swift/host")
+if(SWIFT_HOST_VARIANT_SDK MATCHES "LINUX|ANDROID|OPENBSD|FREEBSD" AND BOOTSTRAPPING_MODE STREQUAL "HOSTTOOLS")
+  # Runtime INSTALL_RPATH are set by 'add_swift_host_library', but that expects
+  # libSwiftScan be installed in 'lib'. But since it's actually installed in 'lib/swift/host',
+  # we need to have correct runtime path to 'lib/swift/{platform}'.
+  # FIXME: BUILD_RPATH and INSTALL_PATH should be different
+  # FIXME: add_swift_host_library should accept 'DESTINATION' and handle installation
+  # FIXME: Build this library into 'lib/swift/host/' instead of 'lib/'
   set_property(
     TARGET libSwiftScan
-    APPEND PROPERTY INSTALL_RPATH "@loader_path/../host")
+    APPEND PROPERTY INSTALL_RPATH "$ORIGIN/../${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_LIB_SUBDIR}"
+  )
+endif()
+
+if(SWIFT_SWIFT_PARSER)
+  if(SWIFT_HOST_VARIANT_SDK IN_LIST SWIFT_DARWIN_PLATFORMS)
+    # Ensure that we can find the host shared libraries.
+    set_property(
+      TARGET libSwiftScan
+      APPEND PROPERTY INSTALL_RPATH "@loader_path/swift/host")
+    set_property(
+      TARGET libSwiftScan
+      APPEND PROPERTY INSTALL_RPATH "@loader_path/../host")
+  elseif(SWIFT_HOST_VARIANT_SDK MATCHES "LINUX|ANDROID|OPENBSD|FREEBSD")
+    set_property(
+      TARGET libSwiftScan
+      APPEND PROPERTY INSTALL_RPATH "$ORIGIN/swift/host")
+    set_property(
+      TARGET libSwiftScan
+      APPEND PROPERTY INSTALL_RPATH "$ORIGIN/../host")
+  endif()
 endif()
 
 add_llvm_symbol_exports(libSwiftScan ${LLVM_EXPORTED_SYMBOL_FILE})
diff --git a/tools/swift-compatibility-symbols/CMakeLists.txt b/tools/swift-compatibility-symbols/CMakeLists.txt
index e28de9182cf4f..fff7ad8112af9 100644
--- a/tools/swift-compatibility-symbols/CMakeLists.txt
+++ b/tools/swift-compatibility-symbols/CMakeLists.txt
@@ -2,6 +2,7 @@ add_swift_host_tool(swift-compatibility-symbols
   swift-compatibility-symbols.cpp
   LLVM_LINK_COMPONENTS support
   SWIFT_COMPONENT tools
+  DOES_NOT_USE_SWIFT
 )
 
 set(syms_file "${CMAKE_BINARY_DIR}/share/swift/compatibility-symbols")
diff --git a/tools/swift-def-to-strings-converter/CMakeLists.txt b/tools/swift-def-to-strings-converter/CMakeLists.txt
index 2bfd9145a5a30..fa81fe6ae60bc 100644
--- a/tools/swift-def-to-strings-converter/CMakeLists.txt
+++ b/tools/swift-def-to-strings-converter/CMakeLists.txt
@@ -1,6 +1,7 @@
 add_swift_host_tool(swift-def-to-strings-converter
   swift-def-to-strings-converter.cpp
   SWIFT_COMPONENT tools
+  DOES_NOT_USE_SWIFT
 )
 
 target_link_libraries(swift-def-to-strings-converter PRIVATE
diff --git a/tools/swift-serialize-diagnostics/CMakeLists.txt b/tools/swift-serialize-diagnostics/CMakeLists.txt
index 4a1ab49b59ed3..aee14abd2dd32 100644
--- a/tools/swift-serialize-diagnostics/CMakeLists.txt
+++ b/tools/swift-serialize-diagnostics/CMakeLists.txt
@@ -1,6 +1,7 @@
 add_swift_host_tool(swift-serialize-diagnostics
   swift-serialize-diagnostics.cpp
   SWIFT_COMPONENT tools
+  DOES_NOT_USE_SWIFT
 )
 target_link_libraries(swift-serialize-diagnostics PRIVATE
   swiftLocalization)
diff --git a/unittests/SwiftDemangle/CMakeLists.txt b/unittests/SwiftDemangle/CMakeLists.txt
index 9ba1aeb348d2d..d5657e511b811 100644
--- a/unittests/SwiftDemangle/CMakeLists.txt
+++ b/unittests/SwiftDemangle/CMakeLists.txt
@@ -1,5 +1,5 @@
 if(TARGET swiftDemangle)
-  add_swift_unittest(SwiftDemangleTests
+  add_swift_unittest(SwiftDemangleTests IS_TARGET_TEST
     DemangleTest.cpp
   )
   set_target_properties(SwiftDemangleTests
diff --git a/unittests/Threading/CMakeLists.txt b/unittests/Threading/CMakeLists.txt
index 5e0f27c089dc4..232f7d5b2ec34 100644
--- a/unittests/Threading/CMakeLists.txt
+++ b/unittests/Threading/CMakeLists.txt
@@ -1,6 +1,6 @@
 if(("${SWIFT_HOST_VARIANT_SDK}" STREQUAL "${SWIFT_PRIMARY_VARIANT_SDK}") AND
    ("${SWIFT_HOST_VARIANT_ARCH}" STREQUAL "${SWIFT_PRIMARY_VARIANT_ARCH}"))
-  add_swift_unittest(SwiftThreadingTests
+  add_swift_unittest(SwiftThreadingTests IS_TARGET_TEST
     Mutex.cpp
     ConditionVariable.cpp
     Once.cpp
diff --git a/unittests/runtime/CMakeLists.txt b/unittests/runtime/CMakeLists.txt
index 79df463c0edb0..4949ac516320b 100644
--- a/unittests/runtime/CMakeLists.txt
+++ b/unittests/runtime/CMakeLists.txt
@@ -100,7 +100,7 @@ if(("${SWIFT_HOST_VARIANT_SDK}" STREQUAL "${SWIFT_PRIMARY_VARIANT_SDK}") AND
     Actor.cpp
     TaskStatus.cpp)
 
-  add_swift_unittest(SwiftRuntimeTests
+  add_swift_unittest(SwiftRuntimeTests IS_TARGET_TEST
     Array.cpp
     CompatibilityOverrideRuntime.cpp
     CompatibilityOverrideConcurrency.cpp
diff --git a/unittests/runtime/LongTests/CMakeLists.txt b/unittests/runtime/LongTests/CMakeLists.txt
index 592e532f8cf53..a07db267fbcc5 100644
--- a/unittests/runtime/LongTests/CMakeLists.txt
+++ b/unittests/runtime/LongTests/CMakeLists.txt
@@ -34,7 +34,7 @@ if(("${SWIFT_HOST_VARIANT_SDK}" STREQUAL "${SWIFT_PRIMARY_VARIANT_SDK}") AND
     list(APPEND PLATFORM_TARGET_LINK_LIBRARIES DbgHelp;Synchronization)
   endif()
 
-  add_swift_unittest(SwiftRuntimeLongTests
+  add_swift_unittest(SwiftRuntimeLongTests IS_TARGET_TEST
     LongRefcounting.cpp
     ../Stdlib.cpp
     ${PLATFORM_SOURCES}
diff --git a/utils/swift_build_support/swift_build_support/products/earlyswiftsyntax.py b/utils/swift_build_support/swift_build_support/products/earlyswiftsyntax.py
index 9450eee9c9b95..e9b68b02872fc 100644
--- a/utils/swift_build_support/swift_build_support/products/earlyswiftsyntax.py
+++ b/utils/swift_build_support/swift_build_support/products/earlyswiftsyntax.py
@@ -36,7 +36,7 @@ def is_before_build_script_impl_product(cls):
     def should_build(self, host_target):
         # Temporarily disable for non-darwin since this build never works
         # outside of that case currently.
-        if sys.platform != 'darwin':
+        if sys.platform != 'darwin' and sys.platform != 'linux':
             return False
 
         if self.args.build_early_swiftsyntax:
@@ -73,18 +73,10 @@ def test(self, host_target):
         pass
 
     def should_install(self, host_target):
-        """should_install() -> Bool
-
-        Whether or not this product should be installed with the given
-        arguments.
-        """
-        return self.should_build(host_target) and self.args.install_swiftsyntax
+        # The artifacts are copied to build directory of 'swift' and are
+        # installed as a part of 'swift' product.
+        return False
 
     def install(self, host_target):
-        """
-        Perform the install phase for the product.
-
-        This phase might copy the artifacts from the previous phases into a
-        destination directory.
-        """
-        self.install_with_cmake(["install"], self.host_install_destdir(host_target))
+        # No-op.
+        pass