3 files changed, 34 insertions, 5 deletions
diff --git a/lib/msan/CMakeLists.txt b/lib/msan/CMakeLists.txt
index 596d040a5..de5980e56 100644
--- a/lib/msan/CMakeLists.txt
+++ b/lib/msan/CMakeLists.txt
@@ -32,9 +32,11 @@ foreach(arch ${MSAN_SUPPORTED_ARCH})
             $<TARGET_OBJECTS:RTInterception.${arch}>
             $<TARGET_OBJECTS:RTSanitizerCommon.${arch}>
             $<TARGET_OBJECTS:RTSanitizerCommonLibc.${arch}>
+            $<TARGET_OBJECTS:RTUbsan.${arch}>
     CFLAGS ${MSAN_RTL_CFLAGS})
   add_compiler_rt_runtime(clang_rt.msan_cxx-${arch} ${arch} STATIC
     SOURCES ${MSAN_RTL_CXX_SOURCES}
+            $<TARGET_OBJECTS:RTUbsan_cxx.${arch}>
     CFLAGS ${MSAN_RTL_CFLAGS})
   add_dependencies(msan clang_rt.msan-${arch}
                         clang_rt.msan_cxx-${arch})
diff --git a/lib/msan/msan.cc b/lib/msan/msan.cc
index 87a909755..8f741de11 100644
--- a/lib/msan/msan.cc
+++ b/lib/msan/msan.cc
@@ -26,6 +26,8 @@
 #include "sanitizer_common/sanitizer_stacktrace.h"
 #include "sanitizer_common/sanitizer_symbolizer.h"
 #include "sanitizer_common/sanitizer_stackdepot.h"
+#include "ubsan/ubsan_flags.h"
+#include "ubsan/ubsan_init.h"
 
 // ACHTUNG! No system header includes in this file.
 
@@ -133,11 +135,6 @@ static void RegisterMsanFlags(FlagParser *parser, Flags *f) {
 }
 
 static void InitializeFlags() {
-  Flags *f = flags();
-  FlagParser parser;
-  RegisterMsanFlags(&parser, f);
-  RegisterCommonFlags(&parser);
-
   SetCommonFlagsDefaults();
   {
     CommonFlags cf;
@@ -151,14 +148,35 @@ static void InitializeFlags() {
     OverrideCommonFlags(cf);
   }
 
+  Flags *f = flags();
   f->SetDefaults();
 
+  FlagParser parser;
+  RegisterMsanFlags(&parser, f);
+  RegisterCommonFlags(&parser);
+
+#if MSAN_CONTAINS_UBSAN
+  __ubsan::Flags *uf = __ubsan::flags();
+  uf->SetDefaults();
+
+  FlagParser ubsan_parser;
+  __ubsan::RegisterUbsanFlags(&ubsan_parser, uf);
+  RegisterCommonFlags(&ubsan_parser);
+#endif
+
   // Override from user-specified string.
   if (__msan_default_options)
     parser.ParseString(__msan_default_options());
+#if MSAN_CONTAINS_UBSAN
+  const char *ubsan_default_options = __ubsan::MaybeCallUbsanDefaultOptions();
+  ubsan_parser.ParseString(ubsan_default_options);
+#endif
 
   const char *msan_options = GetEnv("MSAN_OPTIONS");
   parser.ParseString(msan_options);
+#if MSAN_CONTAINS_UBSAN
+  ubsan_parser.ParseString(GetEnv("UBSAN_OPTIONS"));
+#endif
   VPrintf(1, "MSAN_OPTIONS: %s\n", msan_options ? msan_options : "<empty>");
 
   SetVerbosity(common_flags()->verbosity);
@@ -392,6 +410,10 @@ void __msan_init() {
   SetCurrentThread(main_thread);
   main_thread->ThreadStart();
 
+#if MSAN_CONTAINS_UBSAN
+  __ubsan::InitAsPlugin();
+#endif
+
   VPrintf(1, "MemorySanitizer init done\n");
 
   msan_init_is_running = 0;
diff --git a/lib/msan/msan.h b/lib/msan/msan.h
index f5f87dd0a..2d48e69d7 100644
--- a/lib/msan/msan.h
+++ b/lib/msan/msan.h
@@ -20,11 +20,16 @@
 #include "sanitizer_common/sanitizer_stacktrace.h"
 #include "msan_interface_internal.h"
 #include "msan_flags.h"
+#include "ubsan/ubsan_platform.h"
 
 #ifndef MSAN_REPLACE_OPERATORS_NEW_AND_DELETE
 # define MSAN_REPLACE_OPERATORS_NEW_AND_DELETE 1
 #endif
 
+#ifndef MSAN_CONTAINS_UBSAN
+# define MSAN_CONTAINS_UBSAN CAN_SANITIZE_UB
+#endif
+
 struct MappingDesc {
   uptr start;
   uptr end;