[CMake] Fix host library builds and rpaths for testing macros

This enables running macro tests on Linux.

Author: DougGregor

cmake/modules/AddPureSwift.cmake

@@ -267,9 +267,15 @@ function(add_pure_swift_host_tool name)
   add_executable(${name} ${APSHT_SOURCES})
   _add_host_swift_compile_options(${name})
 
-  set_property(TARGET ${name}
-    APPEND PROPERTY INSTALL_RPATH
-      "@executable_path/../lib/swift/host")
+  if(${SWIFT_HOST_VARIANT_SDK} IN_LIST SWIFT_DARWIN_PLATFORMS)
+    set_property(TARGET ${name}
+      APPEND PROPERTY INSTALL_RPATH
+        "@executable_path/../lib/swift/host")
+  else()
+    set_property(TARGET ${name}
+      APPEND PROPERTY INSTALL_RPATH
+        "$ORIGIN/../lib/swift/host")
+  endif()
 
   set_property(TARGET ${name}
     PROPERTY BUILD_WITH_INSTALL_RPATH YES)

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

test/lit.cfg

@@ -544,9 +544,16 @@ else:
         "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))
 
+# Parse the host triple.
+(host_cpu, host_vendor, host_os, host_vers) = re.match('([^-]+)-([^-]+)-([^0-9-]+)(.*)', config.host_triple).groups()
+
+if platform.system() == 'Darwin':
+    host_build_extra_rpath=""
+else:
+    host_build_extra_rpath="-Xlinker -rpath -Xlinker %s" % (make_path(config.swift_lib_dir, 'swift', host_os))
+
 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)
-)
+    "%s -sdk %s -target %s -I %s -L %s %s" % (config.swiftc_driver, config.host_sdkroot, config.host_triple, config.swift_host_lib_dir, config.swift_host_lib_dir, host_build_extra_rpath))
 
 config.substitutions.append( ('%llvm_obj_root', config.llvm_obj_root) )
 config.substitutions.append( ('%swift-lib-dir', config.swift_lib_dir) )