diff --git a/llvm/utils/gn/build/BUILD.gn b/llvm/utils/gn/build/BUILD.gn
--- a/llvm/utils/gn/build/BUILD.gn
+++ b/llvm/utils/gn/build/BUILD.gn
@@ -235,6 +235,27 @@
       ]
     }
   }
+
+  if (use_ubsan) {
+    assert(is_clang && current_os == "linux",
+           "ubsan only supported on Linux/Clang")
+    cflags += [ "-fsanitize=undefined" ]
+    ldflags += [ "-fsanitize=undefined" ]
+  }
+
+  if (use_asan) {
+    assert(is_clang && current_os == "linux",
+           "asan only supported on Linux/Clang")
+    cflags += [ "-fsanitize=address" ]
+    ldflags += [ "-fsanitize=address" ]
+  }
+
+  if (use_tsan) {
+    assert(is_clang && current_os == "linux",
+           "tsan only supported on Linux/Clang")
+    cflags += [ "-fsanitize=thread" ]
+    ldflags += [ "-fsanitize=thread" ]
+  }
 }
 
 config("no_exceptions") {
diff --git a/llvm/utils/gn/build/buildflags.gni b/llvm/utils/gn/build/buildflags.gni
--- a/llvm/utils/gn/build/buildflags.gni
+++ b/llvm/utils/gn/build/buildflags.gni
@@ -1,6 +1,15 @@
 declare_args() {
   # Whether to build with debug information.
   is_debug = false
+
+  # Whether to build with tsan.
+  use_tsan = false
+
+  # Whether to build with ubsan.
+  use_ubsan = false
+
+  # Whether to build with asan.
+  use_asan = false
 }
 
 # args that depend on other args must live in a later declare_args() block.