Index: llvm/utils/gn/secondary/llvm/unittests/BUILD.gn
===================================================================
--- llvm/utils/gn/secondary/llvm/unittests/BUILD.gn
+++ llvm/utils/gn/secondary/llvm/unittests/BUILD.gn
@@ -12,9 +12,7 @@
     "DebugInfo/CodeView:DebugInfoCodeViewTests",
     "DebugInfo/DWARF:DebugInfoDWARFTests",
     "DebugInfo/MSF:DebugInfoMSFTests",
-
-    # FIXME: Add.
-    #"DebugInfo/PDB:DebugInfoPDBTests",
+    "DebugInfo/PDB:DebugInfoPDBTests",
     "Demangle:DemangleTests",
 
     # FIXME: Add.
@@ -31,8 +29,6 @@
     "ObjectYAML:ObjectYAMLTests",
     "OptRemarks:OptRemarksTests",
     "Option:OptionTests",
-    "OptRemarks:OptRemarksTests",
-    "Option:OptionTests",
 
     # FIXME: Add.
     #"Passes:PluginsTests",
@@ -51,7 +47,7 @@
     "tools/llvm-exegesis:LLVMExegesisTests",
   ]
 
-  # Target-dependend unit tests.
+  # Target-dependent unit tests.
   # FIXME: This matches how they are set up in the cmake build,
   # but if we disable an arch after building with it on, this
   # setup leaves behind stale executables.
Index: llvm/utils/gn/secondary/llvm/unittests/DebugInfo/PDB/BUILD.gn
===================================================================
--- /dev/null
+++ llvm/utils/gn/secondary/llvm/unittests/DebugInfo/PDB/BUILD.gn
@@ -0,0 +1,16 @@
+import("//llvm/utils/unittest/unittest.gni")
+
+unittest_with_input_files("DebugInfoPDBTests") {
+  deps = [
+    "//llvm/lib/DebugInfo/CodeView",
+    "//llvm/lib/DebugInfo/MSF",
+    "//llvm/lib/DebugInfo/PDB",
+    "//llvm/lib/Testing/Support",
+  ]
+  sources = [
+    "HashTableTest.cpp",
+    "NativeSymbolReuseTest.cpp",
+    "PDBApiTest.cpp",
+    "StringTableBuilderTest.cpp",
+  ]
+}
Index: llvm/utils/gn/secondary/llvm/utils/unittest/unittest.gni
===================================================================
--- llvm/utils/gn/secondary/llvm/utils/unittest/unittest.gni
+++ llvm/utils/gn/secondary/llvm/utils/unittest/unittest.gni
@@ -64,3 +64,35 @@
 set_defaults("unittest_with_custom_main") {
   configs = shared_binary_target_configs
 }
+
+# Like unittest(), but for tests that call llvm::getInputFileDirectory().
+# Doing that (and hence using this template) is discouraged.
+# Corresponds to add_unittest_with_input_files() in CMake.
+template("unittest_with_input_files") {
+  executable(target_name) {
+    forward_variables_from(invoker, "*")
+    assert(!defined(invoker.output_dir), "cannot set unittest output_dir")
+    assert(!defined(invoker.testonly), "cannot set unittest testonly")
+    output_dir = target_out_dir
+    deps += [ "//llvm/utils/unittest/UnitTestMain" ]
+    testonly = true
+
+    # DebugInfoPDBTests uses llvm::getInputFileDirectory(), which expects
+    # a file called llvm.srcdir.txt next to the test executable that contains
+    # the path of the source directory (which contains this file).
+    # lit doesn't change the cwd while running googletests, so the cwd isn't
+    # well-defined. This means this has to be an absolute path.
+    # FIXME: This doesn't work with swarming. This should really be a data
+    # dependency, and the cwd while tests requiring input files run should
+    # be required to be some fixed directory.
+    # FIXME: Also, the GN way is to write this file at build time. But since
+    # there's only one use of this, and since this is a pattern that hopefully
+    # will disappear again, and since it doesn't have any measurable performance
+    # hit, write the file at GN time.
+    write_file("$output_dir/llvm.srcdir.txt", rebase_path("."))
+  }
+}
+
+set_defaults("unittest_with_input_files") {
+  configs = shared_binary_target_configs
+}