Index: llvm/utils/gn/secondary/compiler-rt/lib/BUILD.gn
===================================================================
--- llvm/utils/gn/secondary/compiler-rt/lib/BUILD.gn
+++ llvm/utils/gn/secondary/compiler-rt/lib/BUILD.gn
@@ -1,5 +1,6 @@
 group("lib") {
   deps = [
+    "//compiler-rt/lib/asan",
     "//compiler-rt/lib/builtins",
     "//compiler-rt/lib/profile",
   ]
Index: llvm/utils/gn/secondary/compiler-rt/lib/asan/BUILD.gn
===================================================================
--- /dev/null
+++ llvm/utils/gn/secondary/compiler-rt/lib/asan/BUILD.gn
@@ -0,0 +1,203 @@
+import("//compiler-rt/target.gni")
+
+source_set("cxx_sources") {
+  configs -= [ "//llvm/utils/gn/build:llvm_code" ]
+  configs += [ "//llvm/utils/gn/build:crt_code" ]
+  sources = [
+    # Make `gn format` not collapse this, for sync_source_lists_from_cmake.py.
+    "asan_new_delete.cpp",
+  ]
+}
+
+if (current_os == "mac") {
+  asan_target_type = "shared_library"
+} else {
+  asan_target_type = "static_library"
+}
+
+target(asan_target_type, "asan") {
+  configs -= [ "//llvm/utils/gn/build:llvm_code" ]
+  configs += [ "//llvm/utils/gn/build:crt_code" ]
+
+  output_dir = crt_current_out_dir
+  if (current_os == "mac") {
+    output_name = "clang_rt.asan_osx_dynamic"
+  } else {
+    assert(current_os != "win", "FIXME")
+    output_name = "clang_rt.asan$crt_current_target_suffix"
+  }
+
+  deps = [
+    ":asan_cxx",
+    "//compiler-rt/lib/interception:sources",
+    "//compiler-rt/lib/lsan:common_sources",
+    "//compiler-rt/lib/sanitizer_common:sources",
+    "//compiler-rt/lib/ubsan:cxx_sources",
+    "//compiler-rt/lib/ubsan:sources",
+  ]
+
+  if (asan_target_type == "static_library") {
+    complete_static_lib = true
+    configs -= [ "//llvm/utils/gn/build:thin_archive" ]
+  } else {
+    deps += [ ":cxx_sources" ]
+    defines = [ "ASAN_DYNAMIC" ]
+  }
+
+  sources = [
+    "asan_activation.cpp",
+    "asan_activation.h",
+    "asan_activation_flags.inc",
+    "asan_allocator.cpp",
+    "asan_allocator.h",
+    "asan_debugging.cpp",
+    "asan_descriptions.cpp",
+    "asan_descriptions.h",
+    "asan_errors.cpp",
+    "asan_errors.h",
+    "asan_fake_stack.cpp",
+    "asan_fake_stack.h",
+    "asan_flags.cpp",
+    "asan_flags.h",
+    "asan_flags.inc",
+    "asan_fuchsia.cpp",
+    "asan_globals.cpp",
+    "asan_globals_win.cpp",
+    "asan_init_version.h",
+    "asan_interceptors.cpp",
+    "asan_interceptors.h",
+    "asan_interceptors_memintrinsics.cpp",
+    "asan_interceptors_memintrinsics.h",
+    "asan_interface.inc",
+    "asan_interface_internal.h",
+    "asan_internal.h",
+    "asan_linux.cpp",
+    "asan_lock.h",
+    "asan_mac.cpp",
+    "asan_malloc_linux.cpp",
+    "asan_malloc_local.h",
+    "asan_malloc_mac.cpp",
+    "asan_malloc_win.cpp",
+    "asan_mapping.h",
+    "asan_mapping_myriad.h",
+    "asan_memory_profile.cpp",
+    "asan_poisoning.cpp",
+    "asan_poisoning.h",
+    "asan_posix.cpp",
+    "asan_premap_shadow.cpp",
+    "asan_premap_shadow.h",
+    "asan_report.cpp",
+    "asan_report.h",
+    "asan_rtems.cpp",
+    "asan_rtl.cpp",
+    "asan_scariness_score.h",
+    "asan_shadow_setup.cpp",
+    "asan_stack.cpp",
+    "asan_stack.h",
+    "asan_stats.cpp",
+    "asan_stats.h",
+    "asan_suppressions.cpp",
+    "asan_suppressions.h",
+    "asan_thread.cpp",
+    "asan_thread.h",
+    "asan_win.cpp",
+  ]
+  if (target_os != "mac" && target_os != "win") {
+    sources += [
+      # Make `gn format` not collapse this, for sync_source_lists_from_cmake.py.
+      "asan_interceptors_vfork.S",
+    ]
+  }
+
+  # To be able to include sanitizer_common.
+  include_dirs = [ ".." ]
+
+  # FIXME: have SANITIZER_COMMON_CFLAGS thingy? should fno-builtin be in
+  # crt_code?
+  cflags = [ "-fno-builtin" ]
+  if (target_os != "win") {
+    cflags += [ "-ftls-model=initial-exec" ]
+  }
+
+  # FIXME: link rt dl m pthread log
+  # FIXME: dep on libcxx-headers?
+  # FIXME: add_sanitizer_rt_version_list (cf hwasan)
+  # FIXME: need libclang_rt.asan*.a.syms?
+  # FIXME: windows flags (-Zl -nodefaultlibs)
+  # FIXME: asan_blacklist.txt
+
+  if (target_os == "android") {
+    ldflags = [ "-Wl,-z,global" ]
+  }
+
+  if (target_os == "mac") {
+    # The -U flags below correspond to the add_weak_symbols() calls in CMake.
+    ldflags = [
+      "-lc++",
+      "-lc++abi",
+
+      # asan
+      "-Wl,-U,___asan_default_options",
+      "-Wl,-U,___asan_default_suppressions",
+      "-Wl,-U,___asan_on_error",
+      "-Wl,-U,___asan_set_shadow_00",
+      "-Wl,-U,___asan_set_shadow_f1",
+      "-Wl,-U,___asan_set_shadow_f2",
+      "-Wl,-U,___asan_set_shadow_f3",
+      "-Wl,-U,___asan_set_shadow_f4",
+      "-Wl,-U,___asan_set_shadow_f5",
+      "-Wl,-U,___asan_set_shadow_f6",
+      "-Wl,-U,___asan_set_shadow_f7",
+      "-Wl,-U,___asan_set_shadow_f8",
+
+      # lsan
+      "-Wl,-U,___lsan_default_options",
+      "-Wl,-U,___lsan_default_suppressions",
+      "-Wl,-U,___lsan_is_turned_off",
+
+      # ubsan
+      "-Wl,-U,___ubsan_default_options",
+
+      # sanitizer_common
+      "-Wl,-U,___sanitizer_free_hook",
+      "-Wl,-U,___sanitizer_malloc_hook",
+      "-Wl,-U,___sanitizer_report_error_summary",
+      "-Wl,-U,___sanitizer_sandbox_on_notify",
+      "-Wl,-U,___sanitizer_symbolize_code",
+      "-Wl,-U,___sanitizer_symbolize_data",
+      "-Wl,-U,___sanitizer_symbolize_demangle",
+      "-Wl,-U,___sanitizer_symbolize_flush",
+
+      # xray
+      "-Wl,-U,___start_xray_fn_idx",
+      "-Wl,-U,___start_xray_instr_map",
+      "-Wl,-U,___stop_xray_fn_idx",
+      "-Wl,-U,___stop_xray_instr_map",
+
+      # FIXME: better
+      "-Wl,-install_name,@rpath/libclang_rt.asan_osx_dynamic.dylib",
+    ]
+    # FIXME: -Wl,-rpath
+    # FIXME: codesign (??)
+  }
+}
+
+if (asan_target_type == "static_library") {
+  static_library("asan_cxx") {
+    assert(current_os != "win", "FIXME")
+    output_dir = crt_current_out_dir
+    output_name = "clang_rt.asan_cxx$crt_current_target_suffix"
+    complete_static_lib = true
+    configs -= [ "//llvm/utils/gn/build:thin_archive" ]
+    deps = [ ":cxx_sources" ]
+  }
+}
+
+# FIXME: Move these to real targets.
+source_set("unused") {
+  sources = [
+    "asan_preinit.cpp",
+    "asan_win_dll_thunk.cpp",
+    "asan_win_dynamic_runtime_thunk.cpp",
+  ]
+}
Index: llvm/utils/gn/secondary/compiler-rt/lib/lsan/BUILD.gn
===================================================================
--- /dev/null
+++ llvm/utils/gn/secondary/compiler-rt/lib/lsan/BUILD.gn
@@ -0,0 +1,42 @@
+source_set("common_sources") {
+  configs -= [ "//llvm/utils/gn/build:llvm_code" ]
+  configs += [ "//llvm/utils/gn/build:crt_code" ]
+  defines = [ "UBSAN_CAN_USE_CXXABI" ]
+  deps = [
+    "//compiler-rt/lib/interception:sources",
+    "//compiler-rt/lib/sanitizer_common:sources",
+  ]
+  sources = [
+    "lsan_common.cpp",
+    "lsan_common.h",
+    "lsan_common_fuchsia.cpp",
+    "lsan_common_linux.cpp",
+    "lsan_common_mac.cpp",
+  ]
+}
+
+source_set("sources") {
+  configs -= [ "//llvm/utils/gn/build:llvm_code" ]
+  configs += [ "//llvm/utils/gn/build:crt_code" ]
+  defines = [ "UBSAN_CAN_USE_CXXABI" ]
+  deps = [
+    "//compiler-rt/lib/interception:sources",
+    "//compiler-rt/lib/sanitizer_common:sources",
+  ]
+  sources = [
+    "lsan.cpp",
+    "lsan.h",
+    "lsan_allocator.cpp",
+    "lsan_allocator.h",
+    "lsan_flags.inc",
+    "lsan_fuchsia.cpp",
+    "lsan_interceptors.cpp",
+    "lsan_linux.cpp",
+    "lsan_mac.cpp",
+    "lsan_malloc_mac.cpp",
+    "lsan_posix.cpp",
+    "lsan_preinit.cpp",
+    "lsan_thread.cpp",
+    "lsan_thread.h",
+  ]
+}