Revert "[gn] port f29cfab"

This reverts commit 1995635.
f29cfab was reverted in c6c5413.

llvm/unittests/Analysis/InlineAdvisorPlugin/CMakeLists.txt

@@ -10,9 +10,7 @@ if (NOT WIN32)
   endif()
 
   unset(LLVM_LINK_COMPONENTS)
-  add_llvm_library(InlineAdvisorPlugin MODULE BUILDTREE_ONLY
-    InlineAdvisorPlugin.cpp
-    )
+  add_llvm_library(InlineAdvisorPlugin MODULE BUILDTREE_ONLY InlineAdvisorPlugin.cpp)
   # Put PLUGIN next to the unit test executable.
   set_output_directory(InlineAdvisorPlugin
       BINARY_DIR ${CMAKE_CURRENT_BINARY_DIR}/${CMAKE_CFG_INTDIR}/../

llvm/utils/gn/secondary/llvm/unittests/Analysis/BUILD.gn

@@ -1,5 +1,31 @@
 import("//third-party/unittest/unittest.gni")
 
+# Keyed off LLVM_ENABLE_PLUGINS in the CMake build, which is usually false
+# on Windows and true elsewhere.
+if (host_os != "win") {
+  foreach(plugin, [ "InlineAdvisorPlugin" ]) {
+    loadable_module(plugin) {
+      # Put plugin next to the unit test executable.
+      output_dir = target_out_dir
+
+      sources = [ "$plugin.cpp" ]
+
+      deps = [
+        # TestPlugin doesn't want to link in any LLVM code, it just needs its
+        # headers.
+        "//llvm/include/llvm/IR:public_tablegen",
+      ]
+
+      if (host_os != "mac" && host_os != "win") {
+        # The GN build currently doesn't globally pass -fPIC, but that's
+        # needed for building .so files on ELF.  Just pass it manually
+        # for loadable_modules for now.
+        cflags = [ "-fPIC" ]
+      }
+    }
+  }
+}
+
 unittest("AnalysisTests") {
   deps = [
     "//llvm/lib/Analysis",
@@ -58,7 +84,7 @@ unittest("AnalysisTests") {
   # Otherwise, reconfiguring with plugins disabled will leave behind a stale
   # executable.
   if (host_os != "win") {
-    deps += [ "InlineAdvisorPlugin" ]
+    deps += [ ":InlineAdvisorPlugin" ]
   }
 
   # Support plugins.